diff --git a/ruby/ext/google/protobuf_c/defs.c b/ruby/ext/google/protobuf_c/defs.c
index 49c2ba6..044bb1e 100644
--- a/ruby/ext/google/protobuf_c/defs.c
+++ b/ruby/ext/google/protobuf_c/defs.c
@@ -28,6 +28,8 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+#include <ctype.h>
+#include <errno.h>
 #include "protobuf.h"
 
 // -----------------------------------------------------------------------------
@@ -46,29 +48,292 @@
   return rb_str_new2(s);
 }
 
-static upb_def* check_notfrozen(const upb_def* def) {
-  if (upb_def_isfrozen(def)) {
-    rb_raise(rb_eRuntimeError,
-             "Attempt to modify a frozen descriptor. Once descriptors are "
-             "added to the descriptor pool, they may not be modified.");
+static void rewrite_enum_default(const upb_symtab* symtab,
+                                 google_protobuf_FileDescriptorProto* file,
+                                 google_protobuf_FieldDescriptorProto* field) {
+  /* Look for TYPE_ENUM fields that have a default. */
+  if (google_protobuf_FieldDescriptorProto_type(field) !=
+          google_protobuf_FieldDescriptorProto_TYPE_ENUM ||
+      !google_protobuf_FieldDescriptorProto_has_default_value(field) ||
+      !google_protobuf_FieldDescriptorProto_has_type_name(field)) {
+    return;
   }
-  return (upb_def*)def;
+
+  upb_strview defaultval =
+      google_protobuf_FieldDescriptorProto_default_value(field);
+  upb_strview type_name = google_protobuf_FieldDescriptorProto_type_name(field);
+
+  if (defaultval.size == 0 || !isdigit(defaultval.data[0])) {
+    return;
+  }
+
+  if (type_name.size == 0 || type_name.data[0] != '.') {
+    return;
+  }
+
+  const char *type_name_str = type_name.data + 1;
+
+  char *end;
+  errno = 0;
+  long val = strtol(defaultval.data, &end, 10);
+
+  if (errno != 0 || *end != 0 || val < INT32_MIN || val > INT32_MAX) {
+    return;
+  }
+
+  /* Now find the corresponding enum definition. */
+  const upb_enumdef *e = upb_symtab_lookupenum(symtab, type_name_str);
+  if (e) {
+    /* Look in previously loaded files. */
+    const char *label = upb_enumdef_iton(e, val);
+    if (!label) {
+      return;
+    }
+    google_protobuf_FieldDescriptorProto_set_default_value(
+        field, upb_strview_makez(label));
+  } else {
+    /* Look in enums defined in this file. */
+    const google_protobuf_EnumDescriptorProto* matching_enum = NULL;
+    size_t i, n;
+    const google_protobuf_EnumDescriptorProto* const* enums =
+        google_protobuf_FileDescriptorProto_enum_type(file, &n);
+    for (i = 0; i < n; i++) {
+      if (upb_strview_eql(google_protobuf_EnumDescriptorProto_name(enums[i]),
+                          upb_strview_makez(type_name_str))) {
+        matching_enum = enums[i];
+        break;
+      }
+    }
+
+    if (!matching_enum) {
+      return;
+    }
+
+    const google_protobuf_EnumValueDescriptorProto* const* values =
+        google_protobuf_EnumDescriptorProto_value(matching_enum, &n);
+    for (i = 0; i < n; i++) {
+      if (google_protobuf_EnumValueDescriptorProto_number(values[i]) == val) {
+        google_protobuf_FieldDescriptorProto_set_default_value(
+            field, google_protobuf_EnumValueDescriptorProto_name(values[i]));
+        return;
+      }
+    }
+
+    /* We failed to find an enum default.  But we'll just leave the enum
+     * untouched and let the normal def-building code catch it. */
+  }
 }
 
-static upb_msgdef* check_msg_notfrozen(const upb_msgdef* def) {
-  return upb_downcast_msgdef_mutable(check_notfrozen((const upb_def*)def));
+/* Historically we allowed enum defaults to be specified as a number.  In
+ * retrospect this was a mistake as descriptors require defaults to be
+ * specified as a label. This can make a difference if multiple labels have the
+ * same number.
+ *
+ * Here we do a pass over all enum defaults and rewrite numeric defaults by
+ * looking up their labels.  This is compilcated by the fact that the enum
+ * definition can live in either the symtab or the file_proto.
+ * */
+static void rewrite_enum_defaults(
+    const upb_symtab* symtab, google_protobuf_FileDescriptorProto* file_proto) {
+  size_t i, n;
+  google_protobuf_DescriptorProto** msgs =
+      google_protobuf_FileDescriptorProto_mutable_message_type(file_proto, &n);
+
+  for (i = 0; i < n; i++) {
+    size_t j, m;
+    google_protobuf_FieldDescriptorProto** fields =
+        google_protobuf_DescriptorProto_mutable_field(msgs[i], &m);
+    for (j = 0; j < m; j++) {
+      rewrite_enum_default(symtab, file_proto, fields[j]);
+    }
+  }
 }
 
-static upb_fielddef* check_field_notfrozen(const upb_fielddef* def) {
-  return upb_downcast_fielddef_mutable(check_notfrozen((const upb_def*)def));
+static bool has_prefix(upb_strview str, upb_strview prefix) {
+  return str.size >= prefix.size &&
+         memcmp(str.data, prefix.data, prefix.size) == 0;
 }
 
-static upb_oneofdef* check_oneof_notfrozen(const upb_oneofdef* def) {
-  return (upb_oneofdef*)check_notfrozen((const upb_def*)def);
+static void remove_package(upb_strview *name, upb_strview package) {
+  size_t prefix_len = package.size + 1;
+  if (!has_prefix(*name, package) || prefix_len >= name->size ||
+      name->data[package.size] != '.') {
+    rb_raise(cTypeError,
+             "Bad package name, wasn't prefix: " UPB_STRVIEW_FORMAT
+             ", " UPB_STRVIEW_FORMAT,
+             UPB_STRVIEW_ARGS(*name), UPB_STRVIEW_ARGS(package));
+  }
+  name->data += prefix_len;
+  name->size -= prefix_len;
 }
 
-static upb_enumdef* check_enum_notfrozen(const upb_enumdef* def) {
-  return (upb_enumdef*)check_notfrozen((const upb_def*)def);
+static void remove_path(upb_strview *name) {
+  const char* last = strrchr(name->data, '.');
+  if (last) {
+    size_t remove = last - name->data + 1;
+    name->data += remove;
+    name->size -= remove;
+  }
+}
+
+static void rewrite_nesting(VALUE msg_ent, google_protobuf_DescriptorProto* msg,
+                            google_protobuf_DescriptorProto* const* msgs,
+                            google_protobuf_EnumDescriptorProto* const* enums,
+                            upb_arena *arena) {
+  VALUE submsgs = rb_hash_aref(msg_ent, ID2SYM(rb_intern("msgs")));
+  VALUE enum_pos = rb_hash_aref(msg_ent, ID2SYM(rb_intern("enums")));
+
+  Check_Type(submsgs, T_ARRAY);
+  Check_Type(enum_pos, T_ARRAY);
+
+  int submsg_count = RARRAY_LEN(submsgs);
+  int enum_count = RARRAY_LEN(enum_pos);
+
+  google_protobuf_DescriptorProto** msg_msgs =
+      google_protobuf_DescriptorProto_resize_nested_type(msg, submsg_count,
+                                                         arena);
+  google_protobuf_EnumDescriptorProto** msg_enums =
+      google_protobuf_DescriptorProto_resize_enum_type(msg, enum_count, arena);
+
+  for (int i = 0; i < submsg_count; i++) {
+    VALUE submsg_ent = RARRAY_PTR(submsgs)[i];
+    VALUE pos = rb_hash_aref(submsg_ent, ID2SYM(rb_intern("pos")));
+    msg_msgs[i] = msgs[NUM2INT(pos)];
+    upb_strview name = google_protobuf_DescriptorProto_name(msg_msgs[i]);
+    remove_path(&name);
+    google_protobuf_DescriptorProto_set_name(msg_msgs[i], name);
+    rewrite_nesting(submsg_ent, msg_msgs[i], msgs, enums, arena);
+  }
+
+  for (int i = 0; i < enum_count; i++) {
+    VALUE pos = RARRAY_PTR(enum_pos)[i];
+    msg_enums[i] = enums[NUM2INT(pos)];
+  }
+}
+
+/* We have to do some relatively complicated logic here for backward
+ * compatibility.
+ *
+ * In descriptor.proto, messages are nested inside other messages if that is
+ * what the original .proto file looks like.  For example, suppose we have this
+ * foo.proto:
+ *
+ * package foo;
+ * message Bar {
+ *   message Baz {}
+ * }
+ *
+ * The descriptor for this must look like this:
+ *
+ * file {
+ *   name: "test.proto"
+ *   package: "foo"
+ *   message_type {
+ *     name: "Bar"
+ *     nested_type {
+ *       name: "Baz"
+ *     }
+ *   }
+ * }
+ *
+ * However, the Ruby generated code has always generated messages in a flat,
+ * non-nested way:
+ *
+ * Google::Protobuf::DescriptorPool.generated_pool.build do
+ *   add_message "foo.Bar" do
+ *   end
+ *   add_message "foo.Bar.Baz" do
+ *   end
+ * end
+ *
+ * Here we need to do a translation where we turn this generated code into the
+ * above descriptor.  We need to infer that "foo" is the package name, and not
+ * a message itself.
+ *
+ * We delegate to Ruby to compute the transformation, for more concice and
+ * readable code than we can do in C */
+static void rewrite_names(VALUE _file_builder,
+                          google_protobuf_FileDescriptorProto* file_proto) {
+  FileBuilderContext* file_builder = ruby_to_FileBuilderContext(_file_builder);
+  upb_arena *arena = file_builder->arena;
+  // Build params (package, msg_names, enum_names).
+  VALUE package = Qnil;
+  VALUE msg_names = rb_ary_new();
+  VALUE enum_names = rb_ary_new();
+  size_t msg_count, enum_count, i;
+
+  if (google_protobuf_FileDescriptorProto_has_package(file_proto)) {
+    upb_strview package_str =
+        google_protobuf_FileDescriptorProto_package(file_proto);
+    package = rb_str_new(package_str.data, package_str.size);
+  }
+
+  google_protobuf_DescriptorProto** msgs =
+      google_protobuf_FileDescriptorProto_mutable_message_type(file_proto,
+                                                               &msg_count);
+  for (i = 0; i < msg_count; i++) {
+    upb_strview name = google_protobuf_DescriptorProto_name(msgs[i]);
+    rb_ary_push(msg_names, rb_str_new(name.data, name.size));
+  }
+
+  google_protobuf_EnumDescriptorProto** enums =
+      google_protobuf_FileDescriptorProto_mutable_enum_type(file_proto,
+                                                            &enum_count);
+  for (i = 0; i < enum_count; i++) {
+    upb_strview name = google_protobuf_EnumDescriptorProto_name(enums[i]);
+    rb_ary_push(enum_names, rb_str_new(name.data, name.size));
+  }
+
+  // Call Ruby code to calculate package name and nesting.
+  VALUE args[3] = { package, msg_names, enum_names };
+  VALUE internal = rb_eval_string("Google::Protobuf::Internal");
+  VALUE ret = rb_funcallv(internal, rb_intern("fixup_descriptor"), 3, args);
+  VALUE new_package = rb_ary_entry(ret, 0);
+  VALUE nesting = rb_ary_entry(ret, 1);
+
+  if (package == Qnil && new_package != Qnil) {
+    // We inferred a package name; set this package name on the file and remove
+    // the prefix from all msg/enum names.
+    upb_strview new_package_str =
+        FileBuilderContext_strdup(_file_builder, new_package);
+    google_protobuf_FileDescriptorProto_set_package(file_proto,
+                                                    new_package_str);
+
+    for (i = 0; i < msg_count; i++) {
+      upb_strview name = google_protobuf_DescriptorProto_name(msgs[i]);
+      remove_package(&name, new_package_str);
+      google_protobuf_DescriptorProto_set_name(msgs[i], name);
+    }
+
+    for (i = 0; i < enum_count; i++) {
+      upb_strview name = google_protobuf_EnumDescriptorProto_name(enums[i]);
+      remove_package(&name, new_package_str);
+      google_protobuf_EnumDescriptorProto_set_name(enums[i], name);
+    }
+  }
+
+  VALUE msg_ents = rb_hash_aref(nesting, ID2SYM(rb_intern("msgs")));
+  VALUE enum_ents = rb_hash_aref(nesting, ID2SYM(rb_intern("enums")));
+
+  Check_Type(msg_ents, T_ARRAY);
+  Check_Type(enum_ents, T_ARRAY);
+
+  for (i = 0; i < RARRAY_LEN(msg_ents); i++) {
+    VALUE msg_ent = rb_ary_entry(msg_ents, i);
+    VALUE pos = rb_hash_aref(msg_ent, ID2SYM(rb_intern("pos")));
+    msgs[i] = msgs[NUM2INT(pos)];
+    rewrite_nesting(msg_ent, msgs[i], msgs, enums, arena);
+  }
+
+  for (i = 0; i < RARRAY_LEN(enum_ents); i++) {
+    VALUE enum_pos = rb_ary_entry(enum_ents, i);
+    enums[i] = enums[NUM2INT(enum_pos)];
+  }
+
+  google_protobuf_FileDescriptorProto_resize_message_type(
+      file_proto, RARRAY_LEN(msg_ents), arena);
+  google_protobuf_FileDescriptorProto_resize_enum_type(
+      file_proto, RARRAY_LEN(enum_ents), arena);
 }
 
 // -----------------------------------------------------------------------------
@@ -97,11 +362,21 @@
 DEFINE_CLASS(DescriptorPool, "Google::Protobuf::DescriptorPool");
 
 void DescriptorPool_mark(void* _self) {
+  DescriptorPool* self = _self;
+  rb_gc_mark(self->def_to_descriptor);
 }
 
 void DescriptorPool_free(void* _self) {
   DescriptorPool* self = _self;
+
   upb_symtab_free(self->symtab);
+  upb_handlercache_free(self->fill_handler_cache);
+  upb_handlercache_free(self->pb_serialize_handler_cache);
+  upb_handlercache_free(self->json_serialize_handler_cache);
+  upb_handlercache_free(self->json_serialize_handler_preserve_cache);
+  upb_pbcodecache_free(self->fill_method_cache);
+  upb_json_codecache_free(self->json_fill_method_cache);
+
   xfree(self);
 }
 
@@ -113,15 +388,26 @@
  */
 VALUE DescriptorPool_alloc(VALUE klass) {
   DescriptorPool* self = ALLOC(DescriptorPool);
+  self->def_to_descriptor = rb_hash_new();
+  VALUE ret = TypedData_Wrap_Struct(klass, &_DescriptorPool_type, self);
+
   self->symtab = upb_symtab_new();
-  return TypedData_Wrap_Struct(klass, &_DescriptorPool_type, self);
+  self->fill_handler_cache =
+      upb_handlercache_new(add_handlers_for_message, (void*)ret);
+  self->pb_serialize_handler_cache = upb_pb_encoder_newcache();
+  self->json_serialize_handler_cache = upb_json_printer_newcache(false);
+  self->json_serialize_handler_preserve_cache =
+      upb_json_printer_newcache(true);
+  self->fill_method_cache = upb_pbcodecache_new(self->fill_handler_cache);
+  self->json_fill_method_cache = upb_json_codecache_new();
+
+  return ret;
 }
 
 void DescriptorPool_register(VALUE module) {
   VALUE klass = rb_define_class_under(
       module, "DescriptorPool", rb_cObject);
   rb_define_alloc_func(klass, DescriptorPool_alloc);
-  rb_define_method(klass, "add", DescriptorPool_add, 1);
   rb_define_method(klass, "build", DescriptorPool_build, -1);
   rb_define_method(klass, "lookup", DescriptorPool_lookup, 1);
   rb_define_singleton_method(klass, "generated_pool",
@@ -133,44 +419,6 @@
   generated_pool = rb_class_new_instance(0, NULL, klass);
 }
 
-static void add_descriptor_to_pool(DescriptorPool* self,
-                                   Descriptor* descriptor) {
-  CHECK_UPB(
-      upb_symtab_add(self->symtab, (upb_def**)&descriptor->msgdef, 1,
-                     NULL, &status),
-      "Adding Descriptor to DescriptorPool failed");
-}
-
-static void add_enumdesc_to_pool(DescriptorPool* self,
-                                 EnumDescriptor* enumdesc) {
-  CHECK_UPB(
-      upb_symtab_add(self->symtab, (upb_def**)&enumdesc->enumdef, 1,
-                     NULL, &status),
-      "Adding EnumDescriptor to DescriptorPool failed");
-}
-
-/*
- * call-seq:
- *     DescriptorPool.add(descriptor)
- *
- * Adds the given Descriptor or EnumDescriptor to this pool. All references to
- * other types in a Descriptor's fields must be resolvable within this pool or
- * an exception will be raised.
- */
-VALUE DescriptorPool_add(VALUE _self, VALUE def) {
-  DEFINE_SELF(DescriptorPool, self, _self);
-  VALUE def_klass = rb_obj_class(def);
-  if (def_klass == cDescriptor) {
-    add_descriptor_to_pool(self, ruby_to_Descriptor(def));
-  } else if (def_klass == cEnumDescriptor) {
-    add_enumdesc_to_pool(self, ruby_to_EnumDescriptor(def));
-  } else {
-    rb_raise(rb_eArgError,
-             "Second argument must be a Descriptor or EnumDescriptor.");
-  }
-  return Qnil;
-}
-
 /*
  * call-seq:
  *     DescriptorPool.build(&block)
@@ -182,10 +430,10 @@
  * idiomatic way to define new message and enum types.
  */
 VALUE DescriptorPool_build(int argc, VALUE* argv, VALUE _self) {
-  VALUE ctx = rb_class_new_instance(0, NULL, cBuilder);
+  VALUE ctx = rb_class_new_instance(1, &_self, cBuilder);
   VALUE block = rb_block_proc();
   rb_funcall_with_block(ctx, rb_intern("instance_eval"), 0, NULL, block);
-  rb_funcall(ctx, rb_intern("finalize_to_pool"), 1, _self);
+  Builder_build(ctx);
   return Qnil;
 }
 
@@ -199,11 +447,18 @@
 VALUE DescriptorPool_lookup(VALUE _self, VALUE name) {
   DEFINE_SELF(DescriptorPool, self, _self);
   const char* name_str = get_str(name);
-  const upb_def* def = upb_symtab_lookup(self->symtab, name_str);
-  if (!def) {
-    return Qnil;
+
+  const upb_msgdef* msgdef = upb_symtab_lookupmsg(self->symtab, name_str);
+  if (msgdef) {
+    return get_msgdef_obj(_self, msgdef);
   }
-  return get_def_obj(def);
+
+  const upb_enumdef* enumdef = upb_symtab_lookupenum(self->symtab, name_str);
+  if (enumdef) {
+    return get_enumdef_obj(_self, enumdef);
+  }
+
+  return Qnil;
 }
 
 /*
@@ -228,36 +483,14 @@
 void Descriptor_mark(void* _self) {
   Descriptor* self = _self;
   rb_gc_mark(self->klass);
+  rb_gc_mark(self->descriptor_pool);
 }
 
 void Descriptor_free(void* _self) {
   Descriptor* self = _self;
-  upb_msgdef_unref(self->msgdef, &self->msgdef);
   if (self->layout) {
     free_layout(self->layout);
   }
-  if (self->fill_handlers) {
-    upb_handlers_unref(self->fill_handlers, &self->fill_handlers);
-  }
-  if (self->fill_method) {
-    upb_pbdecodermethod_unref(self->fill_method, &self->fill_method);
-  }
-  if (self->json_fill_method) {
-    upb_json_parsermethod_unref(self->json_fill_method,
-                                &self->json_fill_method);
-  }
-  if (self->pb_serialize_handlers) {
-    upb_handlers_unref(self->pb_serialize_handlers,
-                       &self->pb_serialize_handlers);
-  }
-  if (self->json_serialize_handlers) {
-    upb_handlers_unref(self->json_serialize_handlers,
-                       &self->json_serialize_handlers);
-  }
-  if (self->json_serialize_handlers_preserve) {
-    upb_handlers_unref(self->json_serialize_handlers_preserve,
-                       &self->json_serialize_handlers_preserve);
-  }
   xfree(self);
 }
 
@@ -273,15 +506,10 @@
 VALUE Descriptor_alloc(VALUE klass) {
   Descriptor* self = ALLOC(Descriptor);
   VALUE ret = TypedData_Wrap_Struct(klass, &_Descriptor_type, self);
-  self->msgdef = upb_msgdef_new(&self->msgdef);
+  self->msgdef = NULL;
   self->klass = Qnil;
+  self->descriptor_pool = Qnil;
   self->layout = NULL;
-  self->fill_handlers = NULL;
-  self->fill_method = NULL;
-  self->json_fill_method = NULL;
-  self->pb_serialize_handlers = NULL;
-  self->json_serialize_handlers = NULL;
-  self->json_serialize_handlers_preserve = NULL;
   return ret;
 }
 
@@ -289,16 +517,13 @@
   VALUE klass = rb_define_class_under(
       module, "Descriptor", rb_cObject);
   rb_define_alloc_func(klass, Descriptor_alloc);
-  rb_define_method(klass, "initialize", Descriptor_initialize, 1);
+  rb_define_method(klass, "initialize", Descriptor_initialize, 3);
   rb_define_method(klass, "each", Descriptor_each, 0);
   rb_define_method(klass, "lookup", Descriptor_lookup, 1);
-  rb_define_method(klass, "add_field", Descriptor_add_field, 1);
-  rb_define_method(klass, "add_oneof", Descriptor_add_oneof, 1);
   rb_define_method(klass, "each_oneof", Descriptor_each_oneof, 0);
   rb_define_method(klass, "lookup_oneof", Descriptor_lookup_oneof, 1);
   rb_define_method(klass, "msgclass", Descriptor_msgclass, 0);
   rb_define_method(klass, "name", Descriptor_name, 0);
-  rb_define_method(klass, "name=", Descriptor_name_set, 1);
   rb_define_method(klass, "file_descriptor", Descriptor_file_descriptor, 0);
   rb_include_module(klass, rb_mEnumerable);
   rb_gc_register_address(&cDescriptor);
@@ -307,19 +532,21 @@
 
 /*
  * call-seq:
- *    Descriptor.new(file_descriptor)
+ *    Descriptor.new(c_only_cookie, ptr) => Descriptor
  *
- * Initializes a new descriptor and assigns a file descriptor to it.
+ * Creates a descriptor wrapper object.  May only be called from C.
  */
-VALUE Descriptor_initialize(VALUE _self, VALUE file_descriptor_rb) {
+VALUE Descriptor_initialize(VALUE _self, VALUE cookie,
+                            VALUE descriptor_pool, VALUE ptr) {
   DEFINE_SELF(Descriptor, self, _self);
 
-  FileDescriptor* file_descriptor = ruby_to_FileDescriptor(file_descriptor_rb);
+  if (cookie != c_only_cookie) {
+    rb_raise(rb_eRuntimeError,
+             "Descriptor objects may not be created from Ruby.");
+  }
 
-  CHECK_UPB(
-        upb_filedef_addmsg(file_descriptor->filedef, self->msgdef, NULL, &status),
-        "Failed to associate message to file descriptor.");
-  add_def_obj(file_descriptor->filedef, file_descriptor_rb);
+  self->descriptor_pool = descriptor_pool;
+  self->msgdef = (const upb_msgdef*)NUM2ULL(ptr);
 
   return Qnil;
 }
@@ -332,7 +559,7 @@
  */
 VALUE Descriptor_file_descriptor(VALUE _self) {
   DEFINE_SELF(Descriptor, self, _self);
-  return get_def_obj(upb_def_file(self->msgdef));
+  return get_filedef_obj(self->descriptor_pool, upb_msgdef_file(self->msgdef));
 }
 
 /*
@@ -349,23 +576,6 @@
 
 /*
  * call-seq:
- *    Descriptor.name = name
- *
- * Assigns a name to this message type. The descriptor must not have been added
- * to a pool yet.
- */
-VALUE Descriptor_name_set(VALUE _self, VALUE str) {
-  DEFINE_SELF(Descriptor, self, _self);
-  upb_msgdef* mut_def = check_msg_notfrozen(self->msgdef);
-  const char* name = get_str(str);
-  CHECK_UPB(
-      upb_msgdef_setfullname(mut_def, name, &status),
-      "Error setting Descriptor name");
-  return Qnil;
-}
-
-/*
- * call-seq:
  *     Descriptor.each(&block)
  *
  * Iterates over fields in this message type, yielding to the block on each one.
@@ -378,7 +588,7 @@
        !upb_msg_field_done(&it);
        upb_msg_field_next(&it)) {
     const upb_fielddef* field = upb_msg_iter_field(&it);
-    VALUE obj = get_def_obj(field);
+    VALUE obj = get_fielddef_obj(self->descriptor_pool, field);
     rb_yield(obj);
   }
   return Qnil;
@@ -398,51 +608,7 @@
   if (field == NULL) {
     return Qnil;
   }
-  return get_def_obj(field);
-}
-
-/*
- * call-seq:
- *     Descriptor.add_field(field) => nil
- *
- * Adds the given FieldDescriptor to this message type. This descriptor must not
- * have been added to a pool yet. Raises an exception if a field with the same
- * name or number already exists. Sub-type references (e.g. for fields of type
- * message) are not resolved at this point.
- */
-VALUE Descriptor_add_field(VALUE _self, VALUE obj) {
-  DEFINE_SELF(Descriptor, self, _self);
-  upb_msgdef* mut_def = check_msg_notfrozen(self->msgdef);
-  FieldDescriptor* def = ruby_to_FieldDescriptor(obj);
-  upb_fielddef* mut_field_def = check_field_notfrozen(def->fielddef);
-  CHECK_UPB(
-      upb_msgdef_addfield(mut_def, mut_field_def, NULL, &status),
-      "Adding field to Descriptor failed");
-  add_def_obj(def->fielddef, obj);
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     Descriptor.add_oneof(oneof) => nil
- *
- * Adds the given OneofDescriptor to this message type. This descriptor must not
- * have been added to a pool yet. Raises an exception if a oneof with the same
- * name already exists, or if any of the oneof's fields' names or numbers
- * conflict with an existing field in this message type. All fields in the oneof
- * are added to the message descriptor. Sub-type references (e.g. for fields of
- * type message) are not resolved at this point.
- */
-VALUE Descriptor_add_oneof(VALUE _self, VALUE obj) {
-  DEFINE_SELF(Descriptor, self, _self);
-  upb_msgdef* mut_def = check_msg_notfrozen(self->msgdef);
-  OneofDescriptor* def = ruby_to_OneofDescriptor(obj);
-  upb_oneofdef* mut_oneof_def = check_oneof_notfrozen(def->oneofdef);
-  CHECK_UPB(
-      upb_msgdef_addoneof(mut_def, mut_oneof_def, NULL, &status),
-      "Adding oneof to Descriptor failed");
-  add_def_obj(def->oneofdef, obj);
-  return Qnil;
+  return get_fielddef_obj(self->descriptor_pool, field);
 }
 
 /*
@@ -460,7 +626,7 @@
        !upb_msg_oneof_done(&it);
        upb_msg_oneof_next(&it)) {
     const upb_oneofdef* oneof = upb_msg_iter_oneof(&it);
-    VALUE obj = get_def_obj(oneof);
+    VALUE obj = get_oneofdef_obj(self->descriptor_pool, oneof);
     rb_yield(obj);
   }
   return Qnil;
@@ -480,24 +646,19 @@
   if (oneof == NULL) {
     return Qnil;
   }
-  return get_def_obj(oneof);
+  return get_oneofdef_obj(self->descriptor_pool, oneof);
 }
 
 /*
  * call-seq:
  *     Descriptor.msgclass => message_klass
  *
- * Returns the Ruby class created for this message type. Valid only once the
- * message type has been added to a pool.
+ * Returns the Ruby class created for this message type.
  */
 VALUE Descriptor_msgclass(VALUE _self) {
   DEFINE_SELF(Descriptor, self, _self);
-  if (!upb_def_isfrozen((const upb_def*)self->msgdef)) {
-    rb_raise(rb_eRuntimeError,
-             "Cannot fetch message class from a Descriptor not yet in a pool.");
-  }
   if (self->klass == Qnil) {
-    self->klass = build_class_from_descriptor(self);
+    self->klass = build_class_from_descriptor(_self);
   }
   return self->klass;
 }
@@ -509,12 +670,20 @@
 DEFINE_CLASS(FileDescriptor, "Google::Protobuf::FileDescriptor");
 
 void FileDescriptor_mark(void* _self) {
+  FileDescriptor* self = _self;
+  rb_gc_mark(self->descriptor_pool);
 }
 
 void FileDescriptor_free(void* _self) {
-  FileDescriptor* self = _self;
-  upb_filedef_unref(self->filedef, &self->filedef);
-  xfree(self);
+  xfree(_self);
+}
+
+VALUE FileDescriptor_alloc(VALUE klass) {
+  FileDescriptor* self = ALLOC(FileDescriptor);
+  VALUE ret = TypedData_Wrap_Struct(klass, &_FileDescriptor_type, self);
+  self->descriptor_pool = Qnil;
+  self->filedef = NULL;
+  return ret;
 }
 
 /*
@@ -524,66 +693,34 @@
  * Returns a new file descriptor. The syntax must be set before it's passed
  * to a builder.
  */
-VALUE FileDescriptor_alloc(VALUE klass) {
-  FileDescriptor* self = ALLOC(FileDescriptor);
-  VALUE ret = TypedData_Wrap_Struct(klass, &_FileDescriptor_type, self);
-  upb_filedef* filedef = upb_filedef_new(&self->filedef);
-  self->filedef = filedef;
-  return ret;
+VALUE FileDescriptor_initialize(VALUE _self, VALUE cookie,
+                                VALUE descriptor_pool, VALUE ptr) {
+  DEFINE_SELF(FileDescriptor, self, _self);
+
+  if (cookie != c_only_cookie) {
+    rb_raise(rb_eRuntimeError,
+             "Descriptor objects may not be created from Ruby.");
+  }
+
+  self->descriptor_pool = descriptor_pool;
+  self->filedef = (const upb_filedef*)NUM2ULL(ptr);
+
+  return Qnil;
 }
 
 void FileDescriptor_register(VALUE module) {
   VALUE klass = rb_define_class_under(
       module, "FileDescriptor", rb_cObject);
   rb_define_alloc_func(klass, FileDescriptor_alloc);
-  rb_define_method(klass, "initialize", FileDescriptor_initialize, -1);
+  rb_define_method(klass, "initialize", FileDescriptor_initialize, 3);
   rb_define_method(klass, "name", FileDescriptor_name, 0);
   rb_define_method(klass, "syntax", FileDescriptor_syntax, 0);
-  rb_define_method(klass, "syntax=", FileDescriptor_syntax_set, 1);
   rb_gc_register_address(&cFileDescriptor);
   cFileDescriptor = klass;
 }
 
 /*
  * call-seq:
- *     FileDescriptor.new(name, options = nil) => file
- *
- * Initializes a new file descriptor with the given file name.
- * Also accepts an optional "options" hash, specifying other optional
- * metadata about the file. The options hash currently accepts the following
- *   * "syntax": :proto2 or :proto3 (default: :proto3)
- */
-VALUE FileDescriptor_initialize(int argc, VALUE* argv, VALUE _self) {
-  DEFINE_SELF(FileDescriptor, self, _self);
-
-  VALUE name_rb;
-  VALUE options = Qnil;
-  rb_scan_args(argc, argv, "11", &name_rb, &options);
-
-  if (name_rb != Qnil) {
-    Check_Type(name_rb, T_STRING);
-    const char* name = get_str(name_rb);
-    CHECK_UPB(upb_filedef_setname(self->filedef, name, &status),
-	      "Error setting file name");
-  }
-
-  // Default syntax is proto3.
-  VALUE syntax = ID2SYM(rb_intern("proto3"));
-  if (options != Qnil) {
-    Check_Type(options, T_HASH);
-
-    if (rb_funcall(options, rb_intern("key?"), 1,
-		   ID2SYM(rb_intern("syntax"))) == Qtrue) {
-      syntax = rb_hash_lookup(options, ID2SYM(rb_intern("syntax")));
-    }
-  }
-  FileDescriptor_syntax_set(_self, syntax);
-
-  return Qnil;
-}
-
-/*
- * call-seq:
  *     FileDescriptor.name => name
  *
  * Returns the name of the file.
@@ -613,31 +750,6 @@
   }
 }
 
-/*
- * call-seq:
- *     FileDescriptor.syntax = version
- *
- * Sets this file descriptor's syntax, can be :proto3 or :proto2.
- */
-VALUE FileDescriptor_syntax_set(VALUE _self, VALUE syntax_rb) {
-  DEFINE_SELF(FileDescriptor, self, _self);
-  Check_Type(syntax_rb, T_SYMBOL);
-
-  upb_syntax_t syntax;
-  if (SYM2ID(syntax_rb) == rb_intern("proto3")) {
-    syntax = UPB_SYNTAX_PROTO3;
-  } else if (SYM2ID(syntax_rb) == rb_intern("proto2")) {
-    syntax = UPB_SYNTAX_PROTO2;
-  } else {
-    rb_raise(rb_eArgError, "Expected :proto3 or :proto3, received '%s'",
-	     rb_id2name(SYM2ID(syntax_rb)));
-  }
-
-  CHECK_UPB(upb_filedef_setsyntax(self->filedef, syntax, &status),
-          "Error setting file syntax for proto");
-  return Qnil;
-}
-
 // -----------------------------------------------------------------------------
 // FieldDescriptor.
 // -----------------------------------------------------------------------------
@@ -645,12 +757,12 @@
 DEFINE_CLASS(FieldDescriptor, "Google::Protobuf::FieldDescriptor");
 
 void FieldDescriptor_mark(void* _self) {
+  FieldDescriptor* self = _self;
+  rb_gc_mark(self->descriptor_pool);
 }
 
 void FieldDescriptor_free(void* _self) {
-  FieldDescriptor* self = _self;
-  upb_fielddef_unref(self->fielddef, &self->fielddef);
-  xfree(self);
+  xfree(_self);
 }
 
 /*
@@ -663,9 +775,7 @@
 VALUE FieldDescriptor_alloc(VALUE klass) {
   FieldDescriptor* self = ALLOC(FieldDescriptor);
   VALUE ret = TypedData_Wrap_Struct(klass, &_FieldDescriptor_type, self);
-  upb_fielddef* fielddef = upb_fielddef_new(&self->fielddef);
-  upb_fielddef_setpacked(fielddef, false);
-  self->fielddef = fielddef;
+  self->fielddef = NULL;
   return ret;
 }
 
@@ -673,18 +783,13 @@
   VALUE klass = rb_define_class_under(
       module, "FieldDescriptor", rb_cObject);
   rb_define_alloc_func(klass, FieldDescriptor_alloc);
+  rb_define_method(klass, "initialize", FieldDescriptor_initialize, 3);
   rb_define_method(klass, "name", FieldDescriptor_name, 0);
-  rb_define_method(klass, "name=", FieldDescriptor_name_set, 1);
   rb_define_method(klass, "type", FieldDescriptor_type, 0);
-  rb_define_method(klass, "type=", FieldDescriptor_type_set, 1);
   rb_define_method(klass, "default", FieldDescriptor_default, 0);
-  rb_define_method(klass, "default=", FieldDescriptor_default_set, 1);
   rb_define_method(klass, "label", FieldDescriptor_label, 0);
-  rb_define_method(klass, "label=", FieldDescriptor_label_set, 1);
   rb_define_method(klass, "number", FieldDescriptor_number, 0);
-  rb_define_method(klass, "number=", FieldDescriptor_number_set, 1);
   rb_define_method(klass, "submsg_name", FieldDescriptor_submsg_name, 0);
-  rb_define_method(klass, "submsg_name=", FieldDescriptor_submsg_name_set, 1);
   rb_define_method(klass, "subtype", FieldDescriptor_subtype, 0);
   rb_define_method(klass, "has?", FieldDescriptor_has, 1);
   rb_define_method(klass, "clear", FieldDescriptor_clear, 1);
@@ -696,6 +801,27 @@
 
 /*
  * call-seq:
+ *    EnumDescriptor.new(c_only_cookie, pool, ptr) => EnumDescriptor
+ *
+ * Creates a descriptor wrapper object.  May only be called from C.
+ */
+VALUE FieldDescriptor_initialize(VALUE _self, VALUE cookie,
+                                 VALUE descriptor_pool, VALUE ptr) {
+  DEFINE_SELF(FieldDescriptor, self, _self);
+
+  if (cookie != c_only_cookie) {
+    rb_raise(rb_eRuntimeError,
+             "Descriptor objects may not be created from Ruby.");
+  }
+
+  self->descriptor_pool = descriptor_pool;
+  self->fielddef = (const upb_fielddef*)NUM2ULL(ptr);
+
+  return Qnil;
+}
+
+/*
+ * call-seq:
  *     FieldDescriptor.name => name
  *
  * Returns the name of this field.
@@ -705,22 +831,6 @@
   return rb_str_maybe_null(upb_fielddef_name(self->fielddef));
 }
 
-/*
- * call-seq:
- *     FieldDescriptor.name = name
- *
- * Sets the name of this field. Cannot be called once the containing message
- * type, if any, is added to a pool.
- */
-VALUE FieldDescriptor_name_set(VALUE _self, VALUE str) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  upb_fielddef* mut_def = check_field_notfrozen(self->fielddef);
-  const char* name = get_str(str);
-  CHECK_UPB(upb_fielddef_setname(mut_def, name, &status),
-            "Error setting FieldDescriptor name");
-  return Qnil;
-}
-
 upb_fieldtype_t ruby_to_fieldtype(VALUE type) {
   if (TYPE(type) != T_SYMBOL) {
     rb_raise(rb_eArgError, "Expected symbol for field type.");
@@ -831,6 +941,29 @@
   return Qnil;
 }
 
+VALUE ruby_to_label(VALUE label) {
+  upb_label_t upb_label;
+  bool converted = false;
+
+#define CONVERT(upb, ruby)                                           \
+  if (SYM2ID(label) == rb_intern( # ruby )) {                        \
+    upb_label = UPB_LABEL_ ## upb;                                   \
+    converted = true;                                                \
+  }
+
+  CONVERT(OPTIONAL, optional);
+  CONVERT(REQUIRED, required);
+  CONVERT(REPEATED, repeated);
+
+#undef CONVERT
+
+  if (!converted) {
+    rb_raise(rb_eArgError, "Unknown field label.");
+  }
+
+  return upb_label;
+}
+
 /*
  * call-seq:
  *     FieldDescriptor.type => type
@@ -843,28 +976,11 @@
  */
 VALUE FieldDescriptor_type(VALUE _self) {
   DEFINE_SELF(FieldDescriptor, self, _self);
-  if (!upb_fielddef_typeisset(self->fielddef)) {
-    return Qnil;
-  }
   return descriptortype_to_ruby(upb_fielddef_descriptortype(self->fielddef));
 }
 
 /*
  * call-seq:
- *     FieldDescriptor.type = type
- *
- * Sets this field's type. Cannot be called if field is part of a message type
- * already in a pool.
- */
-VALUE FieldDescriptor_type_set(VALUE _self, VALUE type) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  upb_fielddef* mut_def = check_field_notfrozen(self->fielddef);
-  upb_fielddef_setdescriptortype(mut_def, ruby_to_descriptortype(type));
-  return Qnil;
-}
-
-/*
- * call-seq:
  *     FieldDescriptor.default => default
  *
  * Returns this field's default, as a Ruby object, or nil if not yet set.
@@ -876,60 +992,6 @@
 
 /*
  * call-seq:
- *     FieldDescriptor.default = default
- *
- * Sets this field's default value. Raises an exception when calling with
- * proto syntax 3.
- */
-VALUE FieldDescriptor_default_set(VALUE _self, VALUE default_value) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  upb_fielddef* mut_def = check_field_notfrozen(self->fielddef);
-
-  switch (upb_fielddef_type(mut_def)) {
-    case UPB_TYPE_FLOAT:
-      upb_fielddef_setdefaultfloat(mut_def, NUM2DBL(default_value));
-      break;
-    case UPB_TYPE_DOUBLE:
-      upb_fielddef_setdefaultdouble(mut_def, NUM2DBL(default_value));
-      break;
-    case UPB_TYPE_BOOL:
-      if (!RB_TYPE_P(default_value, T_TRUE) &&
-	  !RB_TYPE_P(default_value, T_FALSE) &&
-	  !RB_TYPE_P(default_value, T_NIL)) {
-        rb_raise(cTypeError, "Expected boolean for default value.");
-      }
-
-      upb_fielddef_setdefaultbool(mut_def, RTEST(default_value));
-      break;
-    case UPB_TYPE_ENUM:
-    case UPB_TYPE_INT32:
-      upb_fielddef_setdefaultint32(mut_def, NUM2INT(default_value));
-      break;
-    case UPB_TYPE_INT64:
-      upb_fielddef_setdefaultint64(mut_def, NUM2INT(default_value));
-      break;
-    case UPB_TYPE_UINT32:
-      upb_fielddef_setdefaultuint32(mut_def, NUM2UINT(default_value));
-      break;
-    case UPB_TYPE_UINT64:
-      upb_fielddef_setdefaultuint64(mut_def, NUM2UINT(default_value));
-      break;
-    case UPB_TYPE_STRING:
-    case UPB_TYPE_BYTES:
-      CHECK_UPB(upb_fielddef_setdefaultcstr(mut_def, StringValuePtr(default_value),
-					    &status),
-                "Error setting default string");
-      break;
-    default:
-      rb_raise(rb_eArgError, "Defaults not supported on field %s.%s",
-	       upb_fielddef_fullname(mut_def), upb_fielddef_name(mut_def));
-  }
-
-  return Qnil;
-}
-
-/*
- * call-seq:
  *     FieldDescriptor.label => label
  *
  * Returns this field's label (i.e., plurality), as a Ruby symbol.
@@ -955,44 +1017,6 @@
 
 /*
  * call-seq:
- *     FieldDescriptor.label = label
- *
- * Sets the label on this field. Cannot be called if field is part of a message
- * type already in a pool.
- */
-VALUE FieldDescriptor_label_set(VALUE _self, VALUE label) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  upb_fielddef* mut_def = check_field_notfrozen(self->fielddef);
-  upb_label_t upb_label = -1;
-  bool converted = false;
-
-  if (TYPE(label) != T_SYMBOL) {
-    rb_raise(rb_eArgError, "Expected symbol for field label.");
-  }
-
-#define CONVERT(upb, ruby)                                           \
-  if (SYM2ID(label) == rb_intern( # ruby )) {                        \
-    upb_label = UPB_LABEL_ ## upb;                                   \
-    converted = true;                                                \
-  }
-
-  CONVERT(OPTIONAL, optional);
-  CONVERT(REQUIRED, required);
-  CONVERT(REPEATED, repeated);
-
-#undef CONVERT
-
-  if (!converted) {
-    rb_raise(rb_eArgError, "Unknown field label.");
-  }
-
-  upb_fielddef_setlabel(mut_def, upb_label);
-
-  return Qnil;
-}
-
-/*
- * call-seq:
  *     FieldDescriptor.number => number
  *
  * Returns the tag number for this field.
@@ -1004,21 +1028,6 @@
 
 /*
  * call-seq:
- *     FieldDescriptor.number = number
- *
- * Sets the tag number for this field. Cannot be called if field is part of a
- * message type already in a pool.
- */
-VALUE FieldDescriptor_number_set(VALUE _self, VALUE number) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  upb_fielddef* mut_def = check_field_notfrozen(self->fielddef);
-  CHECK_UPB(upb_fielddef_setnumber(mut_def, NUM2INT(number), &status),
-            "Error setting field number");
-  return Qnil;
-}
-
-/*
- * call-seq:
  *     FieldDescriptor.submsg_name => submsg_name
  *
  * Returns the name of the message or enum type corresponding to this field, if
@@ -1028,32 +1037,16 @@
  */
 VALUE FieldDescriptor_submsg_name(VALUE _self) {
   DEFINE_SELF(FieldDescriptor, self, _self);
-  if (!upb_fielddef_hassubdef(self->fielddef)) {
-    return Qnil;
+  switch (upb_fielddef_type(self->fielddef)) {
+    case UPB_TYPE_ENUM:
+      return rb_str_new2(
+          upb_enumdef_fullname(upb_fielddef_enumsubdef(self->fielddef)));
+    case UPB_TYPE_MESSAGE:
+      return rb_str_new2(
+          upb_msgdef_fullname(upb_fielddef_msgsubdef(self->fielddef)));
+    default:
+      return Qnil;
   }
-  return rb_str_maybe_null(upb_fielddef_subdefname(self->fielddef));
-}
-
-/*
- * call-seq:
- *     FieldDescriptor.submsg_name = submsg_name
- *
- * Sets the name of the message or enum type corresponding to this field, if it
- * is a message or enum field (respectively). This type name will be resolved
- * within the context of the pool to which the containing message type is added.
- * Cannot be called on field that are not of message or enum type, or on fields
- * that are part of a message type already added to a pool.
- */
-VALUE FieldDescriptor_submsg_name_set(VALUE _self, VALUE value) {
-  DEFINE_SELF(FieldDescriptor, self, _self);
-  upb_fielddef* mut_def = check_field_notfrozen(self->fielddef);
-  const char* str = get_str(value);
-  if (!upb_fielddef_hassubdef(self->fielddef)) {
-    rb_raise(cTypeError, "FieldDescriptor does not have subdef.");
-  }
-  CHECK_UPB(upb_fielddef_setsubdefname(mut_def, str, &status),
-            "Error setting submessage name");
-  return Qnil;
 }
 
 /*
@@ -1067,16 +1060,16 @@
  */
 VALUE FieldDescriptor_subtype(VALUE _self) {
   DEFINE_SELF(FieldDescriptor, self, _self);
-  const upb_def* def;
-
-  if (!upb_fielddef_hassubdef(self->fielddef)) {
-    return Qnil;
+  switch (upb_fielddef_type(self->fielddef)) {
+    case UPB_TYPE_ENUM:
+      return get_enumdef_obj(self->descriptor_pool,
+                             upb_fielddef_enumsubdef(self->fielddef));
+    case UPB_TYPE_MESSAGE:
+      return get_msgdef_obj(self->descriptor_pool,
+                            upb_fielddef_msgsubdef(self->fielddef));
+    default:
+      return Qnil;
   }
-  def = upb_fielddef_subdef(self->fielddef);
-  if (def == NULL) {
-    return Qnil;
-  }
-  return get_def_obj(def);
 }
 
 /*
@@ -1160,12 +1153,12 @@
 DEFINE_CLASS(OneofDescriptor, "Google::Protobuf::OneofDescriptor");
 
 void OneofDescriptor_mark(void* _self) {
+  OneofDescriptor* self = _self;
+  rb_gc_mark(self->descriptor_pool);
 }
 
 void OneofDescriptor_free(void* _self) {
-  OneofDescriptor* self = _self;
-  upb_oneofdef_unref(self->oneofdef, &self->oneofdef);
-  xfree(self);
+  xfree(_self);
 }
 
 /*
@@ -1178,7 +1171,8 @@
 VALUE OneofDescriptor_alloc(VALUE klass) {
   OneofDescriptor* self = ALLOC(OneofDescriptor);
   VALUE ret = TypedData_Wrap_Struct(klass, &_OneofDescriptor_type, self);
-  self->oneofdef = upb_oneofdef_new(&self->oneofdef);
+  self->oneofdef = NULL;
+  self->descriptor_pool = Qnil;
   return ret;
 }
 
@@ -1186,9 +1180,8 @@
   VALUE klass = rb_define_class_under(
       module, "OneofDescriptor", rb_cObject);
   rb_define_alloc_func(klass, OneofDescriptor_alloc);
+  rb_define_method(klass, "initialize", OneofDescriptor_initialize, 3);
   rb_define_method(klass, "name", OneofDescriptor_name, 0);
-  rb_define_method(klass, "name=", OneofDescriptor_name_set, 1);
-  rb_define_method(klass, "add_field", OneofDescriptor_add_field, 1);
   rb_define_method(klass, "each", OneofDescriptor_each, 0);
   rb_include_module(klass, rb_mEnumerable);
   rb_gc_register_address(&cOneofDescriptor);
@@ -1197,6 +1190,27 @@
 
 /*
  * call-seq:
+ *    OneofDescriptor.new(c_only_cookie, pool, ptr) => OneofDescriptor
+ *
+ * Creates a descriptor wrapper object.  May only be called from C.
+ */
+VALUE OneofDescriptor_initialize(VALUE _self, VALUE cookie,
+                                 VALUE descriptor_pool, VALUE ptr) {
+  DEFINE_SELF(OneofDescriptor, self, _self);
+
+  if (cookie != c_only_cookie) {
+    rb_raise(rb_eRuntimeError,
+             "Descriptor objects may not be created from Ruby.");
+  }
+
+  self->descriptor_pool = descriptor_pool;
+  self->oneofdef = (const upb_oneofdef*)NUM2ULL(ptr);
+
+  return Qnil;
+}
+
+/*
+ * call-seq:
  *     OneofDescriptor.name => name
  *
  * Returns the name of this oneof.
@@ -1208,48 +1222,6 @@
 
 /*
  * call-seq:
- *     OneofDescriptor.name = name
- *
- * Sets a new name for this oneof. The oneof must not have been added to a
- * message descriptor yet.
- */
-VALUE OneofDescriptor_name_set(VALUE _self, VALUE value) {
-  DEFINE_SELF(OneofDescriptor, self, _self);
-  upb_oneofdef* mut_def = check_oneof_notfrozen(self->oneofdef);
-  const char* str = get_str(value);
-  CHECK_UPB(upb_oneofdef_setname(mut_def, str, &status),
-            "Error setting oneof name");
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     OneofDescriptor.add_field(field) => nil
- *
- * Adds a field to this oneof. The field may have been added to this oneof in
- * the past, or the message to which this oneof belongs (if any), but may not
- * have already been added to any other oneof or message. Otherwise, an
- * exception is raised.
- *
- * All fields added to the oneof via this method will be automatically added to
- * the message to which this oneof belongs, if it belongs to one currently, or
- * else will be added to any message to which the oneof is later added at the
- * time that it is added.
- */
-VALUE OneofDescriptor_add_field(VALUE _self, VALUE obj) {
-  DEFINE_SELF(OneofDescriptor, self, _self);
-  upb_oneofdef* mut_def = check_oneof_notfrozen(self->oneofdef);
-  FieldDescriptor* def = ruby_to_FieldDescriptor(obj);
-  upb_fielddef* mut_field_def = check_field_notfrozen(def->fielddef);
-  CHECK_UPB(
-      upb_oneofdef_addfield(mut_def, mut_field_def, NULL, &status),
-      "Adding field to OneofDescriptor failed");
-  add_def_obj(def->fielddef, obj);
-  return Qnil;
-}
-
-/*
- * call-seq:
  *     OneofDescriptor.each(&block) => nil
  *
  * Iterates through fields in this oneof, yielding to the block on each one.
@@ -1261,7 +1233,7 @@
        !upb_oneof_done(&it);
        upb_oneof_next(&it)) {
     const upb_fielddef* f = upb_oneof_iter_field(&it);
-    VALUE obj = get_def_obj(f);
+    VALUE obj = get_fielddef_obj(self->descriptor_pool, f);
     rb_yield(obj);
   }
   return Qnil;
@@ -1276,38 +1248,49 @@
 void EnumDescriptor_mark(void* _self) {
   EnumDescriptor* self = _self;
   rb_gc_mark(self->module);
+  rb_gc_mark(self->descriptor_pool);
 }
 
 void EnumDescriptor_free(void* _self) {
-  EnumDescriptor* self = _self;
-  upb_enumdef_unref(self->enumdef, &self->enumdef);
-  xfree(self);
+  xfree(_self);
+}
+
+VALUE EnumDescriptor_alloc(VALUE klass) {
+  EnumDescriptor* self = ALLOC(EnumDescriptor);
+  VALUE ret = TypedData_Wrap_Struct(klass, &_EnumDescriptor_type, self);
+  self->enumdef = NULL;
+  self->module = Qnil;
+  self->descriptor_pool = Qnil;
+  return ret;
 }
 
 /*
  * call-seq:
- *     EnumDescriptor.new => enum_descriptor
+ *    EnumDescriptor.new(c_only_cookie, ptr) => EnumDescriptor
  *
- * Creates a new, empty, enum descriptor. Must be added to a pool before the
- * enum type can be used. The enum type may only be modified prior to adding to
- * a pool.
+ * Creates a descriptor wrapper object.  May only be called from C.
  */
-VALUE EnumDescriptor_alloc(VALUE klass) {
-  EnumDescriptor* self = ALLOC(EnumDescriptor);
-  VALUE ret = TypedData_Wrap_Struct(klass, &_EnumDescriptor_type, self);
-  self->enumdef = upb_enumdef_new(&self->enumdef);
-  self->module = Qnil;
-  return ret;
+VALUE EnumDescriptor_initialize(VALUE _self, VALUE cookie,
+                                VALUE descriptor_pool, VALUE ptr) {
+  DEFINE_SELF(EnumDescriptor, self, _self);
+
+  if (cookie != c_only_cookie) {
+    rb_raise(rb_eRuntimeError,
+             "Descriptor objects may not be created from Ruby.");
+  }
+
+  self->descriptor_pool = descriptor_pool;
+  self->enumdef = (const upb_enumdef*)NUM2ULL(ptr);
+
+  return Qnil;
 }
 
 void EnumDescriptor_register(VALUE module) {
   VALUE klass = rb_define_class_under(
       module, "EnumDescriptor", rb_cObject);
   rb_define_alloc_func(klass, EnumDescriptor_alloc);
-  rb_define_method(klass, "initialize", EnumDescriptor_initialize, 1);
+  rb_define_method(klass, "initialize", EnumDescriptor_initialize, 3);
   rb_define_method(klass, "name", EnumDescriptor_name, 0);
-  rb_define_method(klass, "name=", EnumDescriptor_name_set, 1);
-  rb_define_method(klass, "add_value", EnumDescriptor_add_value, 2);
   rb_define_method(klass, "lookup_name", EnumDescriptor_lookup_name, 1);
   rb_define_method(klass, "lookup_value", EnumDescriptor_lookup_value, 1);
   rb_define_method(klass, "each", EnumDescriptor_each, 0);
@@ -1320,31 +1303,14 @@
 
 /*
  * call-seq:
- *    Descriptor.new(file_descriptor)
- *
- * Initializes a new descriptor and assigns a file descriptor to it.
- */
-VALUE EnumDescriptor_initialize(VALUE _self, VALUE file_descriptor_rb) {
-  DEFINE_SELF(EnumDescriptor, self, _self);
-  FileDescriptor* file_descriptor = ruby_to_FileDescriptor(file_descriptor_rb);
-  CHECK_UPB(
-        upb_filedef_addenum(file_descriptor->filedef, self->enumdef,
-			    NULL, &status),
-        "Failed to associate enum to file descriptor.");
-  add_def_obj(file_descriptor->filedef, file_descriptor_rb);
-
-  return Qnil;
-}
-
-/*
- * call-seq:
- *    Descriptor.file_descriptor
+ *    EnumDescriptor.file_descriptor
  *
  * Returns the FileDescriptor object this enum belongs to.
  */
 VALUE EnumDescriptor_file_descriptor(VALUE _self) {
   DEFINE_SELF(EnumDescriptor, self, _self);
-  return get_def_obj(upb_def_file(self->enumdef));
+  return get_filedef_obj(self->descriptor_pool,
+                         upb_enumdef_file(self->enumdef));
 }
 
 /*
@@ -1360,40 +1326,6 @@
 
 /*
  * call-seq:
- *     EnumDescriptor.name = name
- *
- * Sets the name of this enum type. Cannot be called if the enum type has
- * already been added to a pool.
- */
-VALUE EnumDescriptor_name_set(VALUE _self, VALUE str) {
-  DEFINE_SELF(EnumDescriptor, self, _self);
-  upb_enumdef* mut_def = check_enum_notfrozen(self->enumdef);
-  const char* name = get_str(str);
-  CHECK_UPB(upb_enumdef_setfullname(mut_def, name, &status),
-            "Error setting EnumDescriptor name");
-  return Qnil;
-}
-
-/*
- * call-seq:
- *     EnumDescriptor.add_value(key, value)
- *
- * Adds a new key => value mapping to this enum type. Key must be given as a
- * Ruby symbol. Cannot be called if the enum type has already been added to a
- * pool. Will raise an exception if the key or value is already in use.
- */
-VALUE EnumDescriptor_add_value(VALUE _self, VALUE name, VALUE number) {
-  DEFINE_SELF(EnumDescriptor, self, _self);
-  upb_enumdef* mut_def = check_enum_notfrozen(self->enumdef);
-  const char* name_str = rb_id2name(SYM2ID(name));
-  int32_t val = NUM2INT(number);
-  CHECK_UPB(upb_enumdef_addval(mut_def, name_str, val, &status),
-            "Error adding value to enum");
-  return Qnil;
-}
-
-/*
- * call-seq:
  *     EnumDescriptor.lookup_name(name) => value
  *
  * Returns the numeric value corresponding to the given key name (as a Ruby
@@ -1454,18 +1386,12 @@
  * call-seq:
  *     EnumDescriptor.enummodule => module
  *
- * Returns the Ruby module corresponding to this enum type. Cannot be called
- * until the enum descriptor has been added to a pool.
+ * Returns the Ruby module corresponding to this enum type.
  */
 VALUE EnumDescriptor_enummodule(VALUE _self) {
   DEFINE_SELF(EnumDescriptor, self, _self);
-  if (!upb_def_isfrozen((const upb_def*)self->enumdef)) {
-    rb_raise(rb_eRuntimeError,
-             "Cannot fetch enum module from an EnumDescriptor not yet "
-             "in a pool.");
-  }
   if (self->module == Qnil) {
-    self->module = build_module_from_enumdesc(self);
+    self->module = build_module_from_enumdesc(_self);
   }
   return self->module;
 }
@@ -1479,8 +1405,7 @@
 
 void MessageBuilderContext_mark(void* _self) {
   MessageBuilderContext* self = _self;
-  rb_gc_mark(self->descriptor);
-  rb_gc_mark(self->builder);
+  rb_gc_mark(self->file_builder);
 }
 
 void MessageBuilderContext_free(void* _self) {
@@ -1492,8 +1417,7 @@
   MessageBuilderContext* self = ALLOC(MessageBuilderContext);
   VALUE ret = TypedData_Wrap_Struct(
       klass, &_MessageBuilderContext_type, self);
-  self->descriptor = Qnil;
-  self->builder = Qnil;
+  self->file_builder = Qnil;
   return ret;
 }
 
@@ -1514,65 +1438,109 @@
 
 /*
  * call-seq:
- *     MessageBuilderContext.new(desc, builder) => context
+ *     MessageBuilderContext.new(file_builder, name) => context
  *
  * Create a new message builder context around the given message descriptor and
  * builder context. This class is intended to serve as a DSL context to be used
  * with #instance_eval.
  */
 VALUE MessageBuilderContext_initialize(VALUE _self,
-                                       VALUE msgdef,
-                                       VALUE builder) {
+                                       VALUE _file_builder,
+                                       VALUE name) {
   DEFINE_SELF(MessageBuilderContext, self, _self);
-  self->descriptor = msgdef;
-  self->builder = builder;
+  FileBuilderContext* file_builder = ruby_to_FileBuilderContext(_file_builder);
+  google_protobuf_FileDescriptorProto* file_proto = file_builder->file_proto;
+
+  self->file_builder = _file_builder;
+  self->msg_proto = google_protobuf_FileDescriptorProto_add_message_type(
+      file_proto, file_builder->arena);
+
+  google_protobuf_DescriptorProto_set_name(
+      self->msg_proto, FileBuilderContext_strdup(_file_builder, name));
+
   return Qnil;
 }
 
-static VALUE msgdef_add_field(VALUE msgdef_rb,
-                              const char* label, VALUE name,
-                              VALUE type, VALUE number,
-                              VALUE type_class,
-                              VALUE options) {
-  VALUE fielddef_rb = rb_class_new_instance(0, NULL, cFieldDescriptor);
-  VALUE name_str = rb_str_new2(rb_id2name(SYM2ID(name)));
+static void msgdef_add_field(VALUE msgbuilder_rb, upb_label_t label, VALUE name,
+                             VALUE type, VALUE number, VALUE type_class,
+                             VALUE options, int oneof_index) {
+  DEFINE_SELF(MessageBuilderContext, self, msgbuilder_rb);
+  FileBuilderContext* file_context =
+      ruby_to_FileBuilderContext(self->file_builder);
+  google_protobuf_FieldDescriptorProto* field_proto =
+      google_protobuf_DescriptorProto_add_field(self->msg_proto,
+                                                file_context->arena);
 
-  rb_funcall(fielddef_rb, rb_intern("label="), 1, ID2SYM(rb_intern(label)));
-  rb_funcall(fielddef_rb, rb_intern("name="), 1, name_str);
-  rb_funcall(fielddef_rb, rb_intern("type="), 1, type);
-  rb_funcall(fielddef_rb, rb_intern("number="), 1, number);
+
+  Check_Type(name, T_SYMBOL);
+  VALUE name_str = rb_id2str(SYM2ID(name));
+
+  google_protobuf_FieldDescriptorProto_set_name(
+      field_proto, FileBuilderContext_strdup(self->file_builder, name_str));
+  google_protobuf_FieldDescriptorProto_set_number(field_proto, NUM2INT(number));
+  google_protobuf_FieldDescriptorProto_set_label(field_proto, (int)label);
+  google_protobuf_FieldDescriptorProto_set_type(
+      field_proto, (int)ruby_to_descriptortype(type));
 
   if (type_class != Qnil) {
     Check_Type(type_class, T_STRING);
 
     // Make it an absolute type name by prepending a dot.
     type_class = rb_str_append(rb_str_new2("."), type_class);
-    rb_funcall(fielddef_rb, rb_intern("submsg_name="), 1, type_class);
+    google_protobuf_FieldDescriptorProto_set_type_name(
+        field_proto, FileBuilderContext_strdup(self->file_builder, type_class));
   }
 
   if (options != Qnil) {
     Check_Type(options, T_HASH);
 
     if (rb_funcall(options, rb_intern("key?"), 1,
-		   ID2SYM(rb_intern("default"))) == Qtrue) {
-      Descriptor* msgdef = ruby_to_Descriptor(msgdef_rb);
-      if (upb_msgdef_syntax((upb_msgdef*)msgdef->msgdef) == UPB_SYNTAX_PROTO3) {
-        rb_raise(rb_eArgError, "Cannot set :default when using proto3 syntax.");
-      }
+                   ID2SYM(rb_intern("default"))) == Qtrue) {
+      VALUE default_value =
+          rb_hash_lookup(options, ID2SYM(rb_intern("default")));
 
-      FieldDescriptor* fielddef = ruby_to_FieldDescriptor(fielddef_rb);
-      if (!upb_fielddef_haspresence((upb_fielddef*)fielddef->fielddef) ||
-	  upb_fielddef_issubmsg((upb_fielddef*)fielddef->fielddef)) {
-        rb_raise(rb_eArgError, "Cannot set :default on this kind of field.");
-      }
+      /* Call #to_s since all defaults are strings in the descriptor. */
+      default_value = rb_funcall(default_value, rb_intern("to_s"), 0);
 
-      rb_funcall(fielddef_rb, rb_intern("default="), 1,
-		 rb_hash_lookup(options, ID2SYM(rb_intern("default"))));
+      google_protobuf_FieldDescriptorProto_set_default_value(
+          field_proto,
+          FileBuilderContext_strdup(self->file_builder, default_value));
     }
   }
 
-  rb_funcall(msgdef_rb, rb_intern("add_field"), 1, fielddef_rb);
-  return fielddef_rb;
+  if (oneof_index >= 0) {
+    google_protobuf_FieldDescriptorProto_set_oneof_index(field_proto,
+                                                         oneof_index);
+  }
+}
+
+static VALUE make_mapentry(VALUE _message_builder, VALUE types, int argc,
+                           VALUE* argv) {
+  DEFINE_SELF(MessageBuilderContext, message_builder, _message_builder);
+  VALUE type_class = rb_ary_entry(types, 2);
+  FileBuilderContext* file_context =
+      ruby_to_FileBuilderContext(message_builder->file_builder);
+  google_protobuf_MessageOptions* options =
+      google_protobuf_DescriptorProto_mutable_options(
+          message_builder->msg_proto, file_context->arena);
+
+  google_protobuf_MessageOptions_set_map_entry(options, true);
+
+  // optional <type> key = 1;
+  rb_funcall(_message_builder, rb_intern("optional"), 3,
+             ID2SYM(rb_intern("key")), rb_ary_entry(types, 0), INT2NUM(1));
+
+  // optional <type> value = 2;
+  if (type_class == Qnil) {
+    rb_funcall(_message_builder, rb_intern("optional"), 3,
+               ID2SYM(rb_intern("value")), rb_ary_entry(types, 1), INT2NUM(2));
+  } else {
+    rb_funcall(_message_builder, rb_intern("optional"), 4,
+               ID2SYM(rb_intern("value")), rb_ary_entry(types, 1), INT2NUM(2),
+               type_class);
+  }
+
+  return Qnil;
 }
 
 /*
@@ -1599,8 +1567,10 @@
     type_class = Qnil;
   }
 
-  return msgdef_add_field(self->descriptor, "optional",
-                          name, type, number, type_class, options);
+  msgdef_add_field(_self, UPB_LABEL_OPTIONAL, name, type, number, type_class,
+                   options, -1);
+
+  return Qnil;
 }
 
 /*
@@ -1631,8 +1601,10 @@
     type_class = Qnil;
   }
 
-  return msgdef_add_field(self->descriptor, "required",
-                          name, type, number, type_class, options);
+  msgdef_add_field(_self, UPB_LABEL_REQUIRED, name, type, number, type_class,
+                   options, -1);
+
+  return Qnil;
 }
 
 /*
@@ -1656,8 +1628,10 @@
   number = argv[2];
   type_class = (argc > 3) ? argv[3] : Qnil;
 
-  return msgdef_add_field(self->descriptor, "repeated",
-                          name, type, number, type_class, Qnil);
+  msgdef_add_field(_self, UPB_LABEL_REPEATED, name, type, number, type_class,
+                   Qnil, -1);
+
+  return Qnil;
 }
 
 /*
@@ -1698,77 +1672,43 @@
              "type.");
   }
 
-  Descriptor* descriptor = ruby_to_Descriptor(self->descriptor);
-  if (upb_msgdef_syntax(descriptor->msgdef) == UPB_SYNTAX_PROTO2) {
+  FileBuilderContext* file_builder =
+      ruby_to_FileBuilderContext(self->file_builder);
+
+  // TODO(haberman): remove this restriction, maps are supported in proto2.
+  if (upb_strview_eql(
+          google_protobuf_FileDescriptorProto_syntax(file_builder->file_proto),
+          upb_strview_makez("proto2"))) {
     rb_raise(rb_eArgError,
-	     "Cannot add a native map field using proto2 syntax.");
+             "Cannot add a native map field using proto2 syntax.");
   }
 
   // Create a new message descriptor for the map entry message, and create a
   // repeated submessage field here with that type.
-  VALUE file_descriptor_rb =
-      rb_funcall(self->descriptor, rb_intern("file_descriptor"), 0);
-  mapentry_desc = rb_class_new_instance(1, &file_descriptor_rb, cDescriptor);
-  mapentry_desc_name = rb_funcall(self->descriptor, rb_intern("name"), 0);
+  upb_strview msg_name = google_protobuf_DescriptorProto_name(self->msg_proto);
+  mapentry_desc_name = rb_str_new(msg_name.data, msg_name.size);
   mapentry_desc_name = rb_str_cat2(mapentry_desc_name, "_MapEntry_");
-  mapentry_desc_name = rb_str_cat2(mapentry_desc_name,
-                                   rb_id2name(SYM2ID(name)));
-  Descriptor_name_set(mapentry_desc, mapentry_desc_name);
+  mapentry_desc_name =
+      rb_str_cat2(mapentry_desc_name, rb_id2name(SYM2ID(name)));
 
-  {
-    // The 'mapentry' attribute has no Ruby setter because we do not want the
-    // user attempting to DIY the setup below; we want to ensure that the fields
-    // are correct. So we reach into the msgdef here to set the bit manually.
-    Descriptor* mapentry_desc_self = ruby_to_Descriptor(mapentry_desc);
-    upb_msgdef_setmapentry((upb_msgdef*)mapentry_desc_self->msgdef, true);
+  // message <msgname>_MapEntry_ { /* ... */ }
+  VALUE args[1] = { mapentry_desc_name };
+  VALUE types = rb_ary_new3(3, key_type, value_type, type_class);
+  rb_block_call(self->file_builder, rb_intern("add_message"), 1, args,
+                make_mapentry, types);
+
+  // If this file is in a package, we need to qualify the map entry type.
+  if (google_protobuf_FileDescriptorProto_has_package(file_builder->file_proto)) {
+    upb_strview package_view =
+        google_protobuf_FileDescriptorProto_package(file_builder->file_proto);
+    VALUE package = rb_str_new(package_view.data, package_view.size);
+    package = rb_str_cat2(package, ".");
+    mapentry_desc_name = rb_str_concat(package, mapentry_desc_name);
   }
 
-  {
-    // optional <type> key = 1;
-    VALUE key_field = rb_class_new_instance(0, NULL, cFieldDescriptor);
-    FieldDescriptor_name_set(key_field, rb_str_new2("key"));
-    FieldDescriptor_label_set(key_field, ID2SYM(rb_intern("optional")));
-    FieldDescriptor_number_set(key_field, INT2NUM(1));
-    FieldDescriptor_type_set(key_field, key_type);
-    Descriptor_add_field(mapentry_desc, key_field);
-  }
-
-  {
-    // optional <type> value = 2;
-    VALUE value_field = rb_class_new_instance(0, NULL, cFieldDescriptor);
-    FieldDescriptor_name_set(value_field, rb_str_new2("value"));
-    FieldDescriptor_label_set(value_field, ID2SYM(rb_intern("optional")));
-    FieldDescriptor_number_set(value_field, INT2NUM(2));
-    FieldDescriptor_type_set(value_field, value_type);
-    if (type_class != Qnil) {
-      VALUE submsg_name = rb_str_new2("."); // prepend '.' to make absolute.
-      submsg_name = rb_str_append(submsg_name, type_class);
-      FieldDescriptor_submsg_name_set(value_field, submsg_name);
-    }
-    Descriptor_add_field(mapentry_desc, value_field);
-  }
-
-  {
-    // Add the map-entry message type to the current builder, and use the type
-    // to create the map field itself.
-    Builder* builder = ruby_to_Builder(self->builder);
-    rb_ary_push(builder->pending_list, mapentry_desc);
-  }
-
-  {
-    VALUE map_field = rb_class_new_instance(0, NULL, cFieldDescriptor);
-    VALUE name_str = rb_str_new2(rb_id2name(SYM2ID(name)));
-    VALUE submsg_name;
-
-    FieldDescriptor_name_set(map_field, name_str);
-    FieldDescriptor_number_set(map_field, number);
-    FieldDescriptor_label_set(map_field, ID2SYM(rb_intern("repeated")));
-    FieldDescriptor_type_set(map_field, ID2SYM(rb_intern("message")));
-    submsg_name = rb_str_new2("."); // prepend '.' to make name absolute.
-    submsg_name = rb_str_append(submsg_name, mapentry_desc_name);
-    FieldDescriptor_submsg_name_set(map_field, submsg_name);
-    Descriptor_add_field(self->descriptor, map_field);
-  }
+  // repeated MapEntry <name> = <number>;
+  rb_funcall(_self, rb_intern("repeated"), 4, name,
+             ID2SYM(rb_intern("message")), number, mapentry_desc_name);
 
   return Qnil;
 }
@@ -1786,14 +1726,26 @@
  */
 VALUE MessageBuilderContext_oneof(VALUE _self, VALUE name) {
   DEFINE_SELF(MessageBuilderContext, self, _self);
-  VALUE oneofdef = rb_class_new_instance(0, NULL, cOneofDescriptor);
-  VALUE args[2] = { oneofdef, self->builder };
+  size_t oneof_count;
+  FileBuilderContext* file_context =
+      ruby_to_FileBuilderContext(self->file_builder);
+
+  // Existing oneof_count becomes oneof_index.
+  google_protobuf_DescriptorProto_oneof_decl(self->msg_proto, &oneof_count);
+
+  // Create oneof_proto and set its name.
+  google_protobuf_OneofDescriptorProto* oneof_proto =
+      google_protobuf_DescriptorProto_add_oneof_decl(self->msg_proto,
+                                                     file_context->arena);
+  VALUE name_str = rb_str_new2(rb_id2name(SYM2ID(name)));
+  upb_strview name_strview = upb_strview_makez(StringValueCStr(name_str));
+  google_protobuf_OneofDescriptorProto_set_name(oneof_proto, name_strview);
+
+  // Evaluate the block with the builder as argument.
+  VALUE args[2] = { INT2NUM(oneof_count), _self };
   VALUE ctx = rb_class_new_instance(2, args, cOneofBuilderContext);
   VALUE block = rb_block_proc();
-  VALUE name_str = rb_str_new2(rb_id2name(SYM2ID(name)));
-  rb_funcall(oneofdef, rb_intern("name="), 1, name_str);
   rb_funcall_with_block(ctx, rb_intern("instance_eval"), 0, NULL, block);
-  Descriptor_add_oneof(self->descriptor, oneofdef);
 
   return Qnil;
 }
@@ -1807,21 +1759,19 @@
 
 void OneofBuilderContext_mark(void* _self) {
   OneofBuilderContext* self = _self;
-  rb_gc_mark(self->descriptor);
-  rb_gc_mark(self->builder);
+  rb_gc_mark(self->message_builder);
 }
 
 void OneofBuilderContext_free(void* _self) {
-  OneofBuilderContext* self = _self;
-  xfree(self);
+  xfree(_self);
 }
 
 VALUE OneofBuilderContext_alloc(VALUE klass) {
   OneofBuilderContext* self = ALLOC(OneofBuilderContext);
   VALUE ret = TypedData_Wrap_Struct(
       klass, &_OneofBuilderContext_type, self);
-  self->descriptor = Qnil;
-  self->builder = Qnil;
+  self->oneof_index = 0;
+  self->message_builder = Qnil;
   return ret;
 }
 
@@ -1838,18 +1788,18 @@
 
 /*
  * call-seq:
- *     OneofBuilderContext.new(desc, builder) => context
+ *     OneofBuilderContext.new(oneof_index, message_builder) => context
  *
  * Create a new oneof builder context around the given oneof descriptor and
  * builder context. This class is intended to serve as a DSL context to be used
  * with #instance_eval.
  */
 VALUE OneofBuilderContext_initialize(VALUE _self,
-                                     VALUE oneofdef,
-                                     VALUE builder) {
+                                     VALUE oneof_index,
+                                     VALUE message_builder) {
   DEFINE_SELF(OneofBuilderContext, self, _self);
-  self->descriptor = oneofdef;
-  self->builder = builder;
+  self->oneof_index = NUM2INT(oneof_index);
+  self->message_builder = message_builder;
   return Qnil;
 }
 
@@ -1870,8 +1820,10 @@
 
   rb_scan_args(argc, argv, "32", &name, &type, &number, &type_class, &options);
 
-  return msgdef_add_field(self->descriptor, "optional",
-                          name, type, number, type_class, options);
+  msgdef_add_field(self->message_builder, UPB_LABEL_OPTIONAL, name, type,
+                   number, type_class, options, self->oneof_index);
+
+  return Qnil;
 }
 
 // -----------------------------------------------------------------------------
@@ -1883,19 +1835,19 @@
 
 void EnumBuilderContext_mark(void* _self) {
   EnumBuilderContext* self = _self;
-  rb_gc_mark(self->enumdesc);
+  rb_gc_mark(self->file_builder);
 }
 
 void EnumBuilderContext_free(void* _self) {
-  EnumBuilderContext* self = _self;
-  xfree(self);
+  xfree(_self);
 }
 
 VALUE EnumBuilderContext_alloc(VALUE klass) {
   EnumBuilderContext* self = ALLOC(EnumBuilderContext);
   VALUE ret = TypedData_Wrap_Struct(
       klass, &_EnumBuilderContext_type, self);
-  self->enumdesc = Qnil;
+  self->enum_proto = NULL;
+  self->file_builder = Qnil;
   return ret;
 }
 
@@ -1903,8 +1855,7 @@
   VALUE klass = rb_define_class_under(
       module, "EnumBuilderContext", rb_cObject);
   rb_define_alloc_func(klass, EnumBuilderContext_alloc);
-  rb_define_method(klass, "initialize",
-                   EnumBuilderContext_initialize, 1);
+  rb_define_method(klass, "initialize", EnumBuilderContext_initialize, 2);
   rb_define_method(klass, "value", EnumBuilderContext_value, 2);
   rb_gc_register_address(&cEnumBuilderContext);
   cEnumBuilderContext = klass;
@@ -1912,20 +1863,24 @@
 
 /*
  * call-seq:
- *     EnumBuilderContext.new(enumdesc) => context
+ *     EnumBuilderContext.new(file_builder) => context
  *
  * Create a new builder context around the given enum descriptor. This class is
  * intended to serve as a DSL context to be used with #instance_eval.
  */
-VALUE EnumBuilderContext_initialize(VALUE _self, VALUE enumdef) {
+VALUE EnumBuilderContext_initialize(VALUE _self, VALUE _file_builder,
+                                    VALUE name) {
   DEFINE_SELF(EnumBuilderContext, self, _self);
-  self->enumdesc = enumdef;
-  return Qnil;
-}
+  FileBuilderContext* file_builder = ruby_to_FileBuilderContext(_file_builder);
+  google_protobuf_FileDescriptorProto* file_proto = file_builder->file_proto;
 
-static VALUE enumdef_add_value(VALUE enumdef,
-                               VALUE name, VALUE number) {
-  rb_funcall(enumdef, rb_intern("add_value"), 2, name, number);
+  self->file_builder = _file_builder;
+  self->enum_proto = google_protobuf_FileDescriptorProto_add_enum_type(
+      file_proto, file_builder->arena);
+
+  google_protobuf_EnumDescriptorProto_set_name(
+      self->enum_proto, FileBuilderContext_strdup(_file_builder, name));
+
   return Qnil;
 }
 
@@ -1938,7 +1893,21 @@
  */
 VALUE EnumBuilderContext_value(VALUE _self, VALUE name, VALUE number) {
   DEFINE_SELF(EnumBuilderContext, self, _self);
-  return enumdef_add_value(self->enumdesc, name, number);
+  FileBuilderContext* file_builder =
+      ruby_to_FileBuilderContext(self->file_builder);
+  Check_Type(name, T_SYMBOL);
+  VALUE name_str = rb_id2str(SYM2ID(name));
+
+  google_protobuf_EnumValueDescriptorProto* enum_value =
+      google_protobuf_EnumDescriptorProto_add_value(self->enum_proto,
+                                                    file_builder->arena);
+
+  google_protobuf_EnumValueDescriptorProto_set_name(
+      enum_value, FileBuilderContext_strdup(self->file_builder, name_str));
+  google_protobuf_EnumValueDescriptorProto_set_number(enum_value,
+                                                      NUM2INT(number));
+
+  return Qnil;
 }
 
 
@@ -1947,33 +1916,49 @@
 // -----------------------------------------------------------------------------
 
 DEFINE_CLASS(FileBuilderContext,
-	     "Google::Protobuf::Internal::FileBuilderContext");
+             "Google::Protobuf::Internal::FileBuilderContext");
 
 void FileBuilderContext_mark(void* _self) {
   FileBuilderContext* self = _self;
-  rb_gc_mark(self->pending_list);
-  rb_gc_mark(self->file_descriptor);
-  rb_gc_mark(self->builder);
+  rb_gc_mark(self->descriptor_pool);
 }
 
 void FileBuilderContext_free(void* _self) {
   FileBuilderContext* self = _self;
+  upb_arena_free(self->arena);
   xfree(self);
 }
 
+upb_strview FileBuilderContext_strdup2(VALUE _self, const char *str) {
+  DEFINE_SELF(FileBuilderContext, self, _self);
+  upb_strview ret;
+  ret.size = strlen(str);
+  char *data = upb_malloc(upb_arena_alloc(self->arena), ret.size + 1);
+  ret.data = data;
+  memcpy(data, str, ret.size);
+  /* Null-terminate required by rewrite_enum_defaults() above. */
+  data[ret.size] = '\0';
+  return ret;
+}
+
+upb_strview FileBuilderContext_strdup(VALUE _self, VALUE rb_str) {
+  const char *str = get_str(rb_str);
+  return FileBuilderContext_strdup2(_self, str);
+}
+
 VALUE FileBuilderContext_alloc(VALUE klass) {
   FileBuilderContext* self = ALLOC(FileBuilderContext);
   VALUE ret = TypedData_Wrap_Struct(klass, &_FileBuilderContext_type, self);
-  self->pending_list = Qnil;
-  self->file_descriptor = Qnil;
-  self->builder = Qnil;
+  self->arena = upb_arena_new();
+  self->file_proto = google_protobuf_FileDescriptorProto_new(self->arena);
+  self->descriptor_pool = Qnil;
   return ret;
 }
 
 void FileBuilderContext_register(VALUE module) {
   VALUE klass = rb_define_class_under(module, "FileBuilderContext", rb_cObject);
   rb_define_alloc_func(klass, FileBuilderContext_alloc);
-  rb_define_method(klass, "initialize", FileBuilderContext_initialize, 2);
+  rb_define_method(klass, "initialize", FileBuilderContext_initialize, 3);
   rb_define_method(klass, "add_message", FileBuilderContext_add_message, 1);
   rb_define_method(klass, "add_enum", FileBuilderContext_add_enum, 1);
   rb_gc_register_address(&cFileBuilderContext);
@@ -1982,18 +1967,38 @@
 
 /*
  * call-seq:
- *     FileBuilderContext.new(file_descriptor, builder) => context
+ *     FileBuilderContext.new(descriptor_pool) => context
  *
  * Create a new file builder context for the given file descriptor and
  * builder context. This class is intended to serve as a DSL context to be used
  * with #instance_eval.
  */
-VALUE FileBuilderContext_initialize(VALUE _self, VALUE file_descriptor,
-				    VALUE builder) {
+VALUE FileBuilderContext_initialize(VALUE _self, VALUE descriptor_pool,
+                                    VALUE name, VALUE options) {
   DEFINE_SELF(FileBuilderContext, self, _self);
-  self->pending_list = rb_ary_new();
-  self->file_descriptor = file_descriptor;
-  self->builder = builder;
+  self->descriptor_pool = descriptor_pool;
+
+  google_protobuf_FileDescriptorProto_set_name(
+      self->file_proto, FileBuilderContext_strdup(_self, name));
+
+  // Default syntax for Ruby is proto3.
+  google_protobuf_FileDescriptorProto_set_syntax(
+      self->file_proto,
+      FileBuilderContext_strdup(_self, rb_str_new2("proto3")));
+
+  if (options != Qnil) {
+    Check_Type(options, T_HASH);
+
+    VALUE syntax = rb_hash_lookup2(options, ID2SYM(rb_intern("syntax")), Qnil);
+
+    if (syntax != Qnil) {
+      Check_Type(syntax, T_SYMBOL);
+      VALUE syntax_str = rb_id2str(SYM2ID(syntax));
+      google_protobuf_FileDescriptorProto_set_syntax(
+          self->file_proto, FileBuilderContext_strdup(_self, syntax_str));
+    }
+  }
+
   return Qnil;
 }
 
@@ -2010,13 +2015,10 @@
  */
 VALUE FileBuilderContext_add_message(VALUE _self, VALUE name) {
   DEFINE_SELF(FileBuilderContext, self, _self);
-  VALUE msgdef = rb_class_new_instance(1, &self->file_descriptor, cDescriptor);
-  VALUE args[2] = { msgdef, self->builder };
+  VALUE args[2] = { _self, name };
   VALUE ctx = rb_class_new_instance(2, args, cMessageBuilderContext);
   VALUE block = rb_block_proc();
-  rb_funcall(msgdef, rb_intern("name="), 1, name);
   rb_funcall_with_block(ctx, rb_intern("instance_eval"), 0, NULL, block);
-  rb_ary_push(self->pending_list, msgdef);
   return Qnil;
 }
 
@@ -2032,19 +2034,26 @@
  */
 VALUE FileBuilderContext_add_enum(VALUE _self, VALUE name) {
   DEFINE_SELF(FileBuilderContext, self, _self);
-  VALUE enumdef =
-      rb_class_new_instance(1, &self->file_descriptor, cEnumDescriptor);
-  VALUE ctx = rb_class_new_instance(1, &enumdef, cEnumBuilderContext);
+  VALUE args[2] = { _self, name };
+  VALUE ctx = rb_class_new_instance(2, args, cEnumBuilderContext);
   VALUE block = rb_block_proc();
-  rb_funcall(enumdef, rb_intern("name="), 1, name);
   rb_funcall_with_block(ctx, rb_intern("instance_eval"), 0, NULL, block);
-  rb_ary_push(self->pending_list, enumdef);
   return Qnil;
 }
 
-VALUE FileBuilderContext_pending_descriptors(VALUE _self) {
+void FileBuilderContext_build(VALUE _self) {
   DEFINE_SELF(FileBuilderContext, self, _self);
-  return self->pending_list;
+  DescriptorPool* pool = ruby_to_DescriptorPool(self->descriptor_pool);
+
+  rewrite_enum_defaults(pool->symtab, self->file_proto);
+  rewrite_names(_self, self->file_proto);
+
+  upb_status status;
+  upb_status_clear(&status);
+  if (!upb_symtab_addfile(pool->symtab, self->file_proto, &status)) {
+    rb_raise(cTypeError, "Unable to add defs to DescriptorPool: %s",
+             upb_status_errmsg(&status));
+  }
 }
 
 // -----------------------------------------------------------------------------
@@ -2055,58 +2064,46 @@
 
 void Builder_mark(void* _self) {
   Builder* self = _self;
-  rb_gc_mark(self->pending_list);
-  rb_gc_mark(self->default_file_descriptor);
+  rb_gc_mark(self->descriptor_pool);
+  rb_gc_mark(self->default_file_builder);
 }
 
 void Builder_free(void* _self) {
-  Builder* self = _self;
-  xfree(self->defs);
-  xfree(self);
+  xfree(_self);
 }
 
-/*
- * call-seq:
- *     Builder.new => builder
- *
- * Creates a new Builder. A Builder can accumulate a set of new message and enum
- * descriptors and atomically register them into a pool in a way that allows for
- * (co)recursive type references.
- */
 VALUE Builder_alloc(VALUE klass) {
   Builder* self = ALLOC(Builder);
   VALUE ret = TypedData_Wrap_Struct(
       klass, &_Builder_type, self);
-  self->pending_list = Qnil;
-  self->defs = NULL;
-  self->default_file_descriptor = Qnil;
+  self->descriptor_pool = Qnil;
+  self->default_file_builder = Qnil;
   return ret;
 }
 
 void Builder_register(VALUE module) {
   VALUE klass = rb_define_class_under(module, "Builder", rb_cObject);
-  rb_define_alloc_func(klass, Builder_alloc);
-  rb_define_method(klass, "initialize", Builder_initialize, 0);
+  rb_define_alloc_func(klass, Builder_alloc); 
+  rb_define_method(klass, "initialize", Builder_initialize, 1);
   rb_define_method(klass, "add_file", Builder_add_file, -1);
   rb_define_method(klass, "add_message", Builder_add_message, 1);
   rb_define_method(klass, "add_enum", Builder_add_enum, 1);
-  rb_define_method(klass, "finalize_to_pool", Builder_finalize_to_pool, 1);
   rb_gc_register_address(&cBuilder);
   cBuilder = klass;
 }
 
 /*
  * call-seq:
- *    Builder.new
+ *     Builder.new(descriptor_pool) => builder
  *
- * Initializes a new builder.
+ * Creates a new Builder. A Builder can accumulate a set of new message and enum
+ * descriptors and atomically register them into a pool in a way that allows for
+ * (co)recursive type references.
  */
-VALUE Builder_initialize(VALUE _self) {
+VALUE Builder_initialize(VALUE _self, VALUE pool) {
   DEFINE_SELF(Builder, self, _self);
-  self->pending_list = rb_ary_new();
-  VALUE file_name = Qnil;
-  self->default_file_descriptor =
-      rb_class_new_instance(1, &file_name, cFileDescriptor);
+  self->descriptor_pool = pool;
+  self->default_file_builder = Qnil;  // Created lazily if needed.
   return Qnil;
 }
 
@@ -2123,17 +2120,34 @@
  */
 VALUE Builder_add_file(int argc, VALUE* argv, VALUE _self) {
   DEFINE_SELF(Builder, self, _self);
-  VALUE file_descriptor = rb_class_new_instance(argc, argv, cFileDescriptor);
-  VALUE args[2] = { file_descriptor, _self };
-  VALUE ctx = rb_class_new_instance(2, args, cFileBuilderContext);
+  VALUE name, options;
+
+  rb_scan_args(argc, argv, "11", &name, &options);
+
+  VALUE args[3] = { self->descriptor_pool, name, options };
+  VALUE ctx = rb_class_new_instance(3, args, cFileBuilderContext);
+
   VALUE block = rb_block_proc();
   rb_funcall_with_block(ctx, rb_intern("instance_eval"), 0, NULL, block);
+  FileBuilderContext_build(ctx);
 
-  rb_ary_concat(self->pending_list,
-      FileBuilderContext_pending_descriptors(ctx));
   return Qnil;
 }
 
+static VALUE Builder_get_default_file(VALUE _self) {
+  DEFINE_SELF(Builder, self, _self);
+
+  /* Lazily create only if legacy builder-level methods are called. */
+  if (self->default_file_builder == Qnil) {
+    VALUE name = rb_str_new2("ruby_default_file.proto");
+    VALUE args [3] = { self->descriptor_pool, name, rb_hash_new() };
+    self->default_file_builder =
+        rb_class_new_instance(3, args, cFileBuilderContext);
+  }
+
+  return self->default_file_builder;
+}
+
 /*
  * call-seq:
  *     Builder.add_message(name, &block)
@@ -2147,14 +2161,9 @@
  */
 VALUE Builder_add_message(VALUE _self, VALUE name) {
   DEFINE_SELF(Builder, self, _self);
-  VALUE msgdef =
-      rb_class_new_instance(1, &self->default_file_descriptor, cDescriptor);
-  VALUE args[2] = { msgdef, _self };
-  VALUE ctx = rb_class_new_instance(2, args, cMessageBuilderContext);
-  VALUE block = rb_block_proc();
-  rb_funcall(msgdef, rb_intern("name="), 1, name);
-  rb_funcall_with_block(ctx, rb_intern("instance_eval"), 0, NULL, block);
-  rb_ary_push(self->pending_list, msgdef);
+  VALUE file_builder = Builder_get_default_file(_self);
+  rb_funcall_with_block(file_builder, rb_intern("add_message"), 1, &name,
+                        rb_block_proc());
   return Qnil;
 }
 
@@ -2172,86 +2181,60 @@
  */
 VALUE Builder_add_enum(VALUE _self, VALUE name) {
   DEFINE_SELF(Builder, self, _self);
-  VALUE enumdef =
-      rb_class_new_instance(1, &self->default_file_descriptor, cEnumDescriptor);
-  VALUE ctx = rb_class_new_instance(1, &enumdef, cEnumBuilderContext);
-  VALUE block = rb_block_proc();
-  rb_funcall(enumdef, rb_intern("name="), 1, name);
-  rb_funcall_with_block(ctx, rb_intern("instance_eval"), 0, NULL, block);
-  rb_ary_push(self->pending_list, enumdef);
+  VALUE file_builder = Builder_get_default_file(_self);
+  rb_funcall_with_block(file_builder, rb_intern("add_enum"), 1, &name,
+                        rb_block_proc());
   return Qnil;
 }
 
-static void proto3_validate_msgdef(const upb_msgdef* msgdef) {
-  // Verify that no required fields exist. proto3 does not support these.
-  upb_msg_field_iter it;
-  for (upb_msg_field_begin(&it, msgdef);
-       !upb_msg_field_done(&it);
-       upb_msg_field_next(&it)) {
-    const upb_fielddef* field = upb_msg_iter_field(&it);
-    if (upb_fielddef_label(field) == UPB_LABEL_REQUIRED) {
-      rb_raise(cTypeError, "Required fields are unsupported in proto3.");
-    }
-  }
-}
-
-static void proto3_validate_enumdef(const upb_enumdef* enumdef) {
-  // Verify that an entry exists with integer value 0. (This is the default
-  // value.)
-  const char* lookup = upb_enumdef_iton(enumdef, 0);
-  if (lookup == NULL) {
-    rb_raise(cTypeError,
-             "Enum definition does not contain a value for '0'.");
-  }
-}
-
-/*
- * call-seq:
- *     Builder.finalize_to_pool(pool)
- *
- * Adds all accumulated message and enum descriptors created in this builder
- * context to the given pool. The operation occurs atomically, and all
- * descriptors can refer to each other (including in cycles). This is the only
- * way to build (co)recursive message definitions.
- *
- * This method is usually called automatically by DescriptorPool#build after it
- * invokes the given user block in the context of the builder. The user should
- * not normally need to call this manually because a Builder is not normally
- * created manually.
- */
-VALUE Builder_finalize_to_pool(VALUE _self, VALUE pool_rb) {
+/* This method is hidden from Ruby, and only called directly from
+ * DescriptorPool_build(). */
+VALUE Builder_build(VALUE _self) {
   DEFINE_SELF(Builder, self, _self);
 
-  DescriptorPool* pool = ruby_to_DescriptorPool(pool_rb);
-
-  REALLOC_N(self->defs, upb_def*, RARRAY_LEN(self->pending_list));
-
-  for (int i = 0; i < RARRAY_LEN(self->pending_list); i++) {
-    VALUE def_rb = rb_ary_entry(self->pending_list, i);
-    if (CLASS_OF(def_rb) == cDescriptor) {
-      self->defs[i] = (upb_def*)ruby_to_Descriptor(def_rb)->msgdef;
-
-      if (upb_filedef_syntax(upb_def_file(self->defs[i])) == UPB_SYNTAX_PROTO3) {
-        proto3_validate_msgdef((const upb_msgdef*)self->defs[i]);
-      }
-    } else if (CLASS_OF(def_rb) == cEnumDescriptor) {
-      self->defs[i] = (upb_def*)ruby_to_EnumDescriptor(def_rb)->enumdef;
-
-      if (upb_filedef_syntax(upb_def_file(self->defs[i])) == UPB_SYNTAX_PROTO3) {
-        proto3_validate_enumdef((const upb_enumdef*)self->defs[i]);
-      }
-    }
+  if (self->default_file_builder != Qnil) {
+    FileBuilderContext_build(self->default_file_builder);
+    self->default_file_builder = Qnil;
   }
 
-  CHECK_UPB(upb_symtab_add(pool->symtab, (upb_def**)self->defs,
-                           RARRAY_LEN(self->pending_list), NULL, &status),
-            "Unable to add defs to DescriptorPool");
-
-  for (int i = 0; i < RARRAY_LEN(self->pending_list); i++) {
-    VALUE def_rb = rb_ary_entry(self->pending_list, i);
-    add_def_obj(self->defs[i], def_rb);
-  }
-
-  self->pending_list = rb_ary_new();
   return Qnil;
 }
+
+static VALUE get_def_obj(VALUE _descriptor_pool, const void* ptr, VALUE klass) {
+  DEFINE_SELF(DescriptorPool, descriptor_pool, _descriptor_pool);
+  VALUE key = ULL2NUM((intptr_t)ptr);
+  VALUE def = rb_hash_aref(descriptor_pool->def_to_descriptor, key);
+
+  if (ptr == NULL) {
+    return Qnil;
+  }
+
+  if (def == Qnil) {
+    // Lazily create wrapper object.
+    VALUE args[3] = { c_only_cookie, _descriptor_pool, key };
+    def = rb_class_new_instance(3, args, klass);
+    rb_hash_aset(descriptor_pool->def_to_descriptor, key, def);
+  }
+
+  return def;
+}
+
+VALUE get_msgdef_obj(VALUE descriptor_pool, const upb_msgdef* def) {
+  return get_def_obj(descriptor_pool, def, cDescriptor);
+}
+
+VALUE get_enumdef_obj(VALUE descriptor_pool, const upb_enumdef* def) {
+  return get_def_obj(descriptor_pool, def, cEnumDescriptor);
+}
+
+VALUE get_fielddef_obj(VALUE descriptor_pool, const upb_fielddef* def) {
+  return get_def_obj(descriptor_pool, def, cFieldDescriptor);
+}
+
+VALUE get_filedef_obj(VALUE descriptor_pool, const upb_filedef* def) {
+  return get_def_obj(descriptor_pool, def, cFileDescriptor);
+}
+
+VALUE get_oneofdef_obj(VALUE descriptor_pool, const upb_oneofdef* def) {
+  return get_def_obj(descriptor_pool, def, cOneofDescriptor);
+}
diff --git a/ruby/ext/google/protobuf_c/encode_decode.c b/ruby/ext/google/protobuf_c/encode_decode.c
index 5ead9b8..fcefff3 100644
--- a/ruby/ext/google/protobuf_c/encode_decode.c
+++ b/ruby/ext/google/protobuf_c/encode_decode.c
@@ -117,18 +117,18 @@
 typedef struct {
   size_t ofs;
   int32_t hasbit;
-  const upb_msgdef *md;
+  VALUE subklass;
 } submsg_handlerdata_t;
 
 // Creates a handlerdata that contains offset and submessage type information.
 static const void *newsubmsghandlerdata(upb_handlers* h,
                                         uint32_t ofs,
                                         int32_t hasbit,
-                                        const upb_fielddef* f) {
+                                        VALUE subklass) {
   submsg_handlerdata_t *hd = ALLOC(submsg_handlerdata_t);
   hd->ofs = ofs;
   hd->hasbit = hasbit;
-  hd->md = upb_fielddef_msgsubdef(f);
+  hd->subklass = subklass;
   upb_handlers_addcleanup(h, hd, xfree);
   return hd;
 }
@@ -137,13 +137,14 @@
   size_t ofs;              // union data slot
   size_t case_ofs;         // oneof_case field
   uint32_t oneof_case_num; // oneof-case number to place in oneof_case field
-  const upb_msgdef *md;    // msgdef, for oneof submessage handler
+  VALUE subklass;
 } oneof_handlerdata_t;
 
 static const void *newoneofhandlerdata(upb_handlers *h,
                                        uint32_t ofs,
                                        uint32_t case_ofs,
-                                       const upb_fielddef *f) {
+                                       const upb_fielddef *f,
+                                       const Descriptor* desc) {
   oneof_handlerdata_t *hd = ALLOC(oneof_handlerdata_t);
   hd->ofs = ofs;
   hd->case_ofs = case_ofs;
@@ -154,11 +155,7 @@
   // create a separate ID space. In addition, using the field tag number here
   // lets us easily look up the field in the oneof accessor.
   hd->oneof_case_num = upb_fielddef_number(f);
-  if (upb_fielddef_type(f) == UPB_TYPE_MESSAGE) {
-    hd->md = upb_fielddef_msgsubdef(f);
-  } else {
-    hd->md = NULL;
-  }
+  hd->subklass = field_type_class(desc->layout, f);
   upb_handlers_addcleanup(h, hd, xfree);
   return hd;
 }
@@ -254,13 +251,13 @@
 }
 
 static bool stringdata_end_handler(void* closure, const void* hd) {
-  VALUE rb_str = closure;
+  VALUE rb_str = (VALUE)closure;
   rb_obj_freeze(rb_str);
   return true;
 }
 
 static bool appendstring_end_handler(void* closure, const void* hd) {
-  VALUE rb_str = closure;
+  VALUE rb_str = (VALUE)closure;
   rb_obj_freeze(rb_str);
   return true;
 }
@@ -269,12 +266,9 @@
 static void *appendsubmsg_handler(void *closure, const void *hd) {
   VALUE ary = (VALUE)closure;
   const submsg_handlerdata_t *submsgdata = hd;
-  VALUE subdesc =
-      get_def_obj((void*)submsgdata->md);
-  VALUE subklass = Descriptor_msgclass(subdesc);
   MessageHeader* submsg;
 
-  VALUE submsg_rb = rb_class_new_instance(0, NULL, subklass);
+  VALUE submsg_rb = rb_class_new_instance(0, NULL, submsgdata->subklass);
   RepeatedField_push(ary, submsg_rb);
 
   TypedData_Get_Struct(submsg_rb, MessageHeader, &Message_type, submsg);
@@ -285,15 +279,12 @@
 static void *submsg_handler(void *closure, const void *hd) {
   MessageHeader* msg = closure;
   const submsg_handlerdata_t* submsgdata = hd;
-  VALUE subdesc =
-      get_def_obj((void*)submsgdata->md);
-  VALUE subklass = Descriptor_msgclass(subdesc);
   VALUE submsg_rb;
   MessageHeader* submsg;
 
   if (DEREF(msg, submsgdata->ofs, VALUE) == Qnil) {
     DEREF(msg, submsgdata->ofs, VALUE) =
-        rb_class_new_instance(0, NULL, subklass);
+        rb_class_new_instance(0, NULL, submsgdata->subklass);
   }
 
   set_hasbit(closure, submsgdata->hasbit);
@@ -309,11 +300,7 @@
   size_t ofs;
   upb_fieldtype_t key_field_type;
   upb_fieldtype_t value_field_type;
-
-  // We know that we can hold this reference because the handlerdata has the
-  // same lifetime as the upb_handlers struct, and the upb_handlers struct holds
-  // a reference to the upb_msgdef, which in turn has references to its subdefs.
-  const upb_def* value_field_subdef;
+  VALUE subklass;
 } map_handlerdata_t;
 
 // Temporary frame for map parsing: at the beginning of a map entry message, a
@@ -388,7 +375,7 @@
 
   if (mapdata->value_field_type == UPB_TYPE_MESSAGE ||
       mapdata->value_field_type == UPB_TYPE_ENUM) {
-    value_field_typeclass = get_def_obj(mapdata->value_field_subdef);
+    value_field_typeclass = mapdata->subklass;
   }
 
   value = native_slot_get(
@@ -411,7 +398,7 @@
 static map_handlerdata_t* new_map_handlerdata(
     size_t ofs,
     const upb_msgdef* mapentry_def,
-    Descriptor* desc) {
+    const Descriptor* desc) {
   const upb_fielddef* key_field;
   const upb_fielddef* value_field;
   map_handlerdata_t* hd = ALLOC(map_handlerdata_t);
@@ -422,7 +409,7 @@
   value_field = upb_msgdef_itof(mapentry_def, MAP_VALUE_FIELD);
   assert(value_field != NULL);
   hd->value_field_type = upb_fielddef_type(value_field);
-  hd->value_field_subdef = upb_fielddef_subdef(value_field);
+  hd->subklass = field_type_class(desc->layout, value_field);
 
   return hd;
 }
@@ -488,16 +475,13 @@
   const oneof_handlerdata_t *oneofdata = hd;
   uint32_t oldcase = DEREF(msg, oneofdata->case_ofs, uint32_t);
 
-  VALUE subdesc =
-      get_def_obj((void*)oneofdata->md);
-  VALUE subklass = Descriptor_msgclass(subdesc);
   VALUE submsg_rb;
   MessageHeader* submsg;
 
   if (oldcase != oneofdata->oneof_case_num ||
       DEREF(msg, oneofdata->ofs, VALUE) == Qnil) {
     DEREF(msg, oneofdata->ofs, VALUE) =
-        rb_class_new_instance(0, NULL, subklass);
+        rb_class_new_instance(0, NULL, oneofdata->subklass);
   }
   // Set the oneof case *after* allocating the new class instance -- otherwise,
   // if the Ruby GC is invoked as part of a call into the VM, it might invoke
@@ -515,12 +499,12 @@
 
 // Set up handlers for a repeated field.
 static void add_handlers_for_repeated_field(upb_handlers *h,
+                                            const Descriptor* desc,
                                             const upb_fielddef *f,
                                             size_t offset) {
-  upb_handlerattr attr = UPB_HANDLERATTR_INITIALIZER;
-  upb_handlerattr_sethandlerdata(&attr, newhandlerdata(h, offset, -1));
+  upb_handlerattr attr = UPB_HANDLERATTR_INIT;
+  attr.handler_data = newhandlerdata(h, offset, -1);
   upb_handlers_setstartseq(h, f, startseq_handler, &attr);
-  upb_handlerattr_uninit(&attr);
 
   switch (upb_fielddef_type(f)) {
 
@@ -551,20 +535,20 @@
       break;
     }
     case UPB_TYPE_MESSAGE: {
-      upb_handlerattr attr = UPB_HANDLERATTR_INITIALIZER;
-      upb_handlerattr_sethandlerdata(&attr, newsubmsghandlerdata(h, 0, -1, f));
+      VALUE subklass = field_type_class(desc->layout, f);
+      upb_handlerattr attr = UPB_HANDLERATTR_INIT;
+      attr.handler_data = newsubmsghandlerdata(h, 0, -1, subklass);
       upb_handlers_setstartsubmsg(h, f, appendsubmsg_handler, &attr);
-      upb_handlerattr_uninit(&attr);
       break;
     }
   }
 }
 
 // Set up handlers for a singular field.
-static void add_handlers_for_singular_field(upb_handlers *h,
-                                            const upb_fielddef *f,
-                                            size_t offset,
-                                            size_t hasbit_off) {
+static void add_handlers_for_singular_field(const Descriptor* desc,
+                                            upb_handlers* h,
+                                            const upb_fielddef* f,
+                                            size_t offset, size_t hasbit_off) {
   // The offset we pass to UPB points to the start of the Message,
   // rather than the start of where our data is stored.
   int32_t hasbit = -1;
@@ -586,23 +570,20 @@
     case UPB_TYPE_STRING:
     case UPB_TYPE_BYTES: {
       bool is_bytes = upb_fielddef_type(f) == UPB_TYPE_BYTES;
-      upb_handlerattr attr = UPB_HANDLERATTR_INITIALIZER;
-      upb_handlerattr_sethandlerdata(&attr, newhandlerdata(h, offset, hasbit));
+      upb_handlerattr attr = UPB_HANDLERATTR_INIT;
+      attr.handler_data = newhandlerdata(h, offset, hasbit);
       upb_handlers_setstartstr(h, f,
                                is_bytes ? bytes_handler : str_handler,
                                &attr);
       upb_handlers_setstring(h, f, stringdata_handler, &attr);
       upb_handlers_setendstr(h, f, stringdata_end_handler, &attr);
-      upb_handlerattr_uninit(&attr);
       break;
     }
     case UPB_TYPE_MESSAGE: {
-      upb_handlerattr attr = UPB_HANDLERATTR_INITIALIZER;
-      upb_handlerattr_sethandlerdata(&attr,
-				     newsubmsghandlerdata(h, offset,
-							  hasbit, f));
+      upb_handlerattr attr = UPB_HANDLERATTR_INIT;
+      attr.handler_data = newsubmsghandlerdata(
+          h, offset, hasbit, field_type_class(desc->layout, f));
       upb_handlers_setstartsubmsg(h, f, submsg_handler, &attr);
-      upb_handlerattr_uninit(&attr);
       break;
     }
   }
@@ -612,36 +593,34 @@
 static void add_handlers_for_mapfield(upb_handlers* h,
                                       const upb_fielddef* fielddef,
                                       size_t offset,
-                                      Descriptor* desc) {
+                                      const Descriptor* desc) {
   const upb_msgdef* map_msgdef = upb_fielddef_msgsubdef(fielddef);
   map_handlerdata_t* hd = new_map_handlerdata(offset, map_msgdef, desc);
-  upb_handlerattr attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr attr = UPB_HANDLERATTR_INIT;
 
   upb_handlers_addcleanup(h, hd, xfree);
-  upb_handlerattr_sethandlerdata(&attr, hd);
+  attr.handler_data = hd;
   upb_handlers_setstartsubmsg(h, fielddef, startmapentry_handler, &attr);
-  upb_handlerattr_uninit(&attr);
 }
 
 // Adds handlers to a map-entry msgdef.
-static void add_handlers_for_mapentry(const upb_msgdef* msgdef,
-                                      upb_handlers* h,
-                                      Descriptor* desc) {
+static void add_handlers_for_mapentry(const upb_msgdef* msgdef, upb_handlers* h,
+                                      const Descriptor* desc) {
   const upb_fielddef* key_field = map_entry_key(msgdef);
   const upb_fielddef* value_field = map_entry_value(msgdef);
   map_handlerdata_t* hd = new_map_handlerdata(0, msgdef, desc);
-  upb_handlerattr attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr attr = UPB_HANDLERATTR_INIT;
 
   upb_handlers_addcleanup(h, hd, xfree);
-  upb_handlerattr_sethandlerdata(&attr, hd);
+  attr.handler_data = hd;
   upb_handlers_setendmsg(h, endmap_handler, &attr);
 
   add_handlers_for_singular_field(
-      h, key_field,
+      desc, h, key_field,
       offsetof(map_parse_frame_t, key_storage),
       MESSAGE_FIELD_NO_HASBIT);
   add_handlers_for_singular_field(
-      h, value_field,
+      desc, h, value_field,
       offsetof(map_parse_frame_t, value_storage),
       MESSAGE_FIELD_NO_HASBIT);
 }
@@ -650,11 +629,11 @@
 static void add_handlers_for_oneof_field(upb_handlers *h,
                                          const upb_fielddef *f,
                                          size_t offset,
-                                         size_t oneof_case_offset) {
-
-  upb_handlerattr attr = UPB_HANDLERATTR_INITIALIZER;
-  upb_handlerattr_sethandlerdata(
-      &attr, newoneofhandlerdata(h, offset, oneof_case_offset, f));
+                                         size_t oneof_case_offset,
+                                         const Descriptor* desc) {
+  upb_handlerattr attr = UPB_HANDLERATTR_INIT;
+  attr.handler_data =
+      newoneofhandlerdata(h, offset, oneof_case_offset, f, desc);
 
   switch (upb_fielddef_type(f)) {
 
@@ -689,8 +668,6 @@
       break;
     }
   }
-
-  upb_handlerattr_uninit(&attr);
 }
 
 static bool unknown_field_handler(void* closure, const void* hd,
@@ -708,11 +685,21 @@
   return true;
 }
 
-static void add_handlers_for_message(const void *closure, upb_handlers *h) {
+void add_handlers_for_message(const void *closure, upb_handlers *h) {
+  const VALUE descriptor_pool = (VALUE)closure;
   const upb_msgdef* msgdef = upb_handlers_msgdef(h);
-  Descriptor* desc = ruby_to_Descriptor(get_def_obj((void*)msgdef));
+  Descriptor* desc =
+      ruby_to_Descriptor(get_msgdef_obj(descriptor_pool, msgdef));
   upb_msg_field_iter i;
 
+  // Ensure layout exists. We may be invoked to create handlers for a given
+  // message if we are included as a submsg of another message type before our
+  // class is actually built, so to work around this, we just create the layout
+  // (and handlers, in the class-building function) on-demand.
+  if (desc->layout == NULL) {
+    desc->layout = create_layout(desc);
+  }
+
   // If this is a mapentry message type, set up a special set of handlers and
   // bail out of the normal (user-defined) message type handling.
   if (upb_msgdef_mapentry(msgdef)) {
@@ -720,15 +707,7 @@
     return;
   }
 
-  // Ensure layout exists. We may be invoked to create handlers for a given
-  // message if we are included as a submsg of another message type before our
-  // class is actually built, so to work around this, we just create the layout
-  // (and handlers, in the class-building function) on-demand.
-  if (desc->layout == NULL) {
-    desc->layout = create_layout(desc->msgdef);
-  }
-
-  upb_handlerattr attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr attr = UPB_HANDLERATTR_INIT;
   upb_handlers_setunknown(h, unknown_field_handler, &attr);
 
   for (upb_msg_field_begin(&i, desc->msgdef);
@@ -742,64 +721,51 @@
       size_t oneof_case_offset =
           desc->layout->fields[upb_fielddef_index(f)].case_offset +
           sizeof(MessageHeader);
-      add_handlers_for_oneof_field(h, f, offset, oneof_case_offset);
+      add_handlers_for_oneof_field(h, f, offset, oneof_case_offset, desc);
     } else if (is_map_field(f)) {
       add_handlers_for_mapfield(h, f, offset, desc);
     } else if (upb_fielddef_isseq(f)) {
-      add_handlers_for_repeated_field(h, f, offset);
+      add_handlers_for_repeated_field(h, desc, f, offset);
     } else {
       add_handlers_for_singular_field(
-          h, f, offset, desc->layout->fields[upb_fielddef_index(f)].hasbit);
+          desc, h, f, offset,
+          desc->layout->fields[upb_fielddef_index(f)].hasbit);
     }
   }
 }
 
-// Creates upb handlers for populating a message.
-static const upb_handlers *new_fill_handlers(Descriptor* desc,
-                                             const void* owner) {
-  // TODO(cfallin, haberman): once upb gets a caching/memoization layer for
-  // handlers, reuse subdef handlers so that e.g. if we already parse
-  // B-with-field-of-type-C, we don't have to rebuild the whole hierarchy to
-  // parse A-with-field-of-type-B-with-field-of-type-C.
-  return upb_handlers_newfrozen(desc->msgdef, owner,
-                                add_handlers_for_message, NULL);
-}
-
 // Constructs the handlers for filling a message's data into an in-memory
 // object.
 const upb_handlers* get_fill_handlers(Descriptor* desc) {
-  if (!desc->fill_handlers) {
-    desc->fill_handlers =
-        new_fill_handlers(desc, &desc->fill_handlers);
-  }
-  return desc->fill_handlers;
-}
-
-// Constructs the upb decoder method for parsing messages of this type.
-// This is called from the message class creation code.
-const upb_pbdecodermethod *new_fillmsg_decodermethod(Descriptor* desc,
-                                                     const void* owner) {
-  const upb_handlers* handlers = get_fill_handlers(desc);
-  upb_pbdecodermethodopts opts;
-  upb_pbdecodermethodopts_init(&opts, handlers);
-
-  return upb_pbdecodermethod_new(&opts, owner);
+  DescriptorPool* pool = ruby_to_DescriptorPool(desc->descriptor_pool);
+  return upb_handlercache_get(pool->fill_handler_cache, desc->msgdef);
 }
 
 static const upb_pbdecodermethod *msgdef_decodermethod(Descriptor* desc) {
-  if (desc->fill_method == NULL) {
-    desc->fill_method = new_fillmsg_decodermethod(
-        desc, &desc->fill_method);
-  }
-  return desc->fill_method;
+  DescriptorPool* pool = ruby_to_DescriptorPool(desc->descriptor_pool);
+  return upb_pbcodecache_get(pool->fill_method_cache, desc->msgdef);
 }
 
 static const upb_json_parsermethod *msgdef_jsonparsermethod(Descriptor* desc) {
-  if (desc->json_fill_method == NULL) {
-    desc->json_fill_method =
-        upb_json_parsermethod_new(desc->msgdef, &desc->json_fill_method);
+  DescriptorPool* pool = ruby_to_DescriptorPool(desc->descriptor_pool);
+  return upb_json_codecache_get(pool->json_fill_method_cache, desc->msgdef);
+}
+
+static const upb_handlers* msgdef_pb_serialize_handlers(Descriptor* desc) {
+  DescriptorPool* pool = ruby_to_DescriptorPool(desc->descriptor_pool);
+  return upb_handlercache_get(pool->pb_serialize_handler_cache, desc->msgdef);
+}
+
+static const upb_handlers* msgdef_json_serialize_handlers(
+    Descriptor* desc, bool preserve_proto_fieldnames) {
+  DescriptorPool* pool = ruby_to_DescriptorPool(desc->descriptor_pool);
+  if (preserve_proto_fieldnames) {
+    return upb_handlercache_get(pool->json_serialize_handler_preserve_cache,
+                                desc->msgdef);
+  } else {
+    return upb_handlercache_get(pool->json_serialize_handler_cache,
+                                desc->msgdef);
   }
-  return desc->json_fill_method;
 }
 
 
@@ -809,7 +775,8 @@
 // if any error occurs.
 #define STACK_ENV_STACKBYTES 4096
 typedef struct {
-  upb_env env;
+  upb_arena *arena;
+  upb_status status;
   const char* ruby_error_template;
   char allocbuf[STACK_ENV_STACKBYTES];
 } stackenv;
@@ -817,29 +784,22 @@
 static void stackenv_init(stackenv* se, const char* errmsg);
 static void stackenv_uninit(stackenv* se);
 
-// Callback invoked by upb if any error occurs during parsing or serialization.
-static bool env_error_func(void* ud, const upb_status* status) {
-  stackenv* se = ud;
-  // Free the env -- rb_raise will longjmp up the stack past the encode/decode
-  // function so it would not otherwise have been freed.
-  stackenv_uninit(se);
-
-  // TODO(haberman): have a way to verify that this is actually a parse error,
-  // instead of just throwing "parse error" unconditionally.
-  rb_raise(cParseError, se->ruby_error_template, upb_status_errmsg(status));
-  // Never reached: rb_raise() always longjmp()s up the stack, past all of our
-  // code, back to Ruby.
-  return false;
-}
-
 static void stackenv_init(stackenv* se, const char* errmsg) {
   se->ruby_error_template = errmsg;
-  upb_env_init2(&se->env, se->allocbuf, sizeof(se->allocbuf), NULL);
-  upb_env_seterrorfunc(&se->env, env_error_func, se);
+  se->arena =
+      upb_arena_init(se->allocbuf, sizeof(se->allocbuf), &upb_alloc_global);
+  upb_status_clear(&se->status);
 }
 
 static void stackenv_uninit(stackenv* se) {
-  upb_env_uninit(&se->env);
+  upb_arena_free(se->arena);
+
+  if (!upb_ok(&se->status)) {
+    // TODO(haberman): have a way to verify that this is actually a parse error,
+    // instead of just throwing "parse error" unconditionally.
+    VALUE errmsg = rb_str_new2(upb_status_errmsg(&se->status));
+    rb_raise(cParseError, se->ruby_error_template, errmsg);
+  }
 }
 
 /*
@@ -870,10 +830,10 @@
     stackenv se;
     upb_sink sink;
     upb_pbdecoder* decoder;
-    stackenv_init(&se, "Error occurred during parsing: %s");
+    stackenv_init(&se, "Error occurred during parsing: %" PRIsVALUE);
 
     upb_sink_reset(&sink, h, msg);
-    decoder = upb_pbdecoder_create(&se.env, method, &sink);
+    decoder = upb_pbdecoder_create(se.arena, method, sink, &se.status);
     upb_bufsrc_putbuf(RSTRING_PTR(data), RSTRING_LEN(data),
                       upb_pbdecoder_input(decoder));
 
@@ -891,8 +851,9 @@
  * format) under the interpretration given by this message class's definition
  * and returns a message object with the corresponding field values.
  *
- * @param options [Hash] options for the decoder
- *   ignore_unknown_fields: set true to ignore unknown fields (default is to raise an error)
+ *  @param options [Hash] options for the decoder
+ *   ignore_unknown_fields: set true to ignore unknown fields (default is to
+ *   raise an error)
  */
 VALUE Message_decode_json(int argc, VALUE* argv, VALUE klass) {
   VALUE descriptor = rb_ivar_get(klass, descriptor_instancevar_interned);
@@ -920,6 +881,7 @@
   if (TYPE(data) != T_STRING) {
     rb_raise(rb_eArgError, "Expected string for JSON data.");
   }
+
   // TODO(cfallin): Check and respect string encoding. If not UTF-8, we need to
   // convert, because string handlers pass data directly to message string
   // fields.
@@ -933,11 +895,11 @@
     upb_sink sink;
     upb_json_parser* parser;
     DescriptorPool* pool = ruby_to_DescriptorPool(generated_pool);
-    stackenv_init(&se, "Error occurred during parsing: %s");
+    stackenv_init(&se, "Error occurred during parsing: %" PRIsVALUE);
 
     upb_sink_reset(&sink, get_fill_handlers(desc), msg);
-    parser = upb_json_parser_create(&se.env, method, pool->symtab,
-                                    &sink, ignore_unknown_fields);
+    parser = upb_json_parser_create(se.arena, method, pool->symtab, sink,
+                                    &se.status, RTEST(ignore_unknown_fields));
     upb_bufsrc_putbuf(RSTRING_PTR(data), RSTRING_LEN(data),
                       upb_json_parser_input(parser));
 
@@ -953,9 +915,8 @@
 
 /* msgvisitor *****************************************************************/
 
-static void putmsg(VALUE msg, const Descriptor* desc,
-                   upb_sink *sink, int depth, bool emit_defaults,
-                   bool is_json, bool open_msg);
+static void putmsg(VALUE msg, const Descriptor* desc, upb_sink sink, int depth,
+                   bool emit_defaults, bool is_json, bool open_msg);
 
 static upb_selector_t getsel(const upb_fielddef *f, upb_handlertype_t type) {
   upb_selector_t ret;
@@ -964,7 +925,7 @@
   return ret;
 }
 
-static void putstr(VALUE str, const upb_fielddef *f, upb_sink *sink) {
+static void putstr(VALUE str, const upb_fielddef *f, upb_sink sink) {
   upb_sink subsink;
 
   if (str == Qnil) return;
@@ -981,12 +942,12 @@
 
   upb_sink_startstr(sink, getsel(f, UPB_HANDLER_STARTSTR), RSTRING_LEN(str),
                     &subsink);
-  upb_sink_putstring(&subsink, getsel(f, UPB_HANDLER_STRING), RSTRING_PTR(str),
+  upb_sink_putstring(subsink, getsel(f, UPB_HANDLER_STRING), RSTRING_PTR(str),
                      RSTRING_LEN(str), NULL);
   upb_sink_endstr(sink, getsel(f, UPB_HANDLER_ENDSTR));
 }
 
-static void putsubmsg(VALUE submsg, const upb_fielddef *f, upb_sink *sink,
+static void putsubmsg(VALUE submsg, const upb_fielddef *f, upb_sink sink,
                       int depth, bool emit_defaults, bool is_json) {
   upb_sink subsink;
   VALUE descriptor;
@@ -998,12 +959,12 @@
   subdesc = ruby_to_Descriptor(descriptor);
 
   upb_sink_startsubmsg(sink, getsel(f, UPB_HANDLER_STARTSUBMSG), &subsink);
-  putmsg(submsg, subdesc, &subsink, depth + 1, emit_defaults, is_json, true);
+  putmsg(submsg, subdesc, subsink, depth + 1, emit_defaults, is_json, true);
   upb_sink_endsubmsg(sink, getsel(f, UPB_HANDLER_ENDSUBMSG));
 }
 
-static void putary(VALUE ary, const upb_fielddef *f, upb_sink *sink,
-                   int depth, bool emit_defaults, bool is_json) {
+static void putary(VALUE ary, const upb_fielddef* f, upb_sink sink, int depth,
+                   bool emit_defaults, bool is_json) {
   upb_sink subsink;
   upb_fieldtype_t type = upb_fielddef_type(f);
   upb_selector_t sel = 0;
@@ -1024,9 +985,9 @@
   for (int i = 0; i < size; i++) {
     void* memory = RepeatedField_index_native(ary, i);
     switch (type) {
-#define T(upbtypeconst, upbtype, ctype)                         \
-  case upbtypeconst:                                            \
-    upb_sink_put##upbtype(&subsink, sel, *((ctype *)memory));   \
+#define T(upbtypeconst, upbtype, ctype)                     \
+  case upbtypeconst:                                        \
+    upb_sink_put##upbtype(subsink, sel, *((ctype*)memory)); \
     break;
 
       T(UPB_TYPE_FLOAT,  float,  float)
@@ -1040,11 +1001,10 @@
 
       case UPB_TYPE_STRING:
       case UPB_TYPE_BYTES:
-        putstr(*((VALUE *)memory), f, &subsink);
+        putstr(*((VALUE *)memory), f, subsink);
         break;
       case UPB_TYPE_MESSAGE:
-        putsubmsg(*((VALUE *)memory), f, &subsink, depth,
-                  emit_defaults, is_json);
+        putsubmsg(*((VALUE*)memory), f, subsink, depth, emit_defaults, is_json);
         break;
 
 #undef T
@@ -1054,12 +1014,8 @@
   upb_sink_endseq(sink, getsel(f, UPB_HANDLER_ENDSEQ));
 }
 
-static void put_ruby_value(VALUE value,
-                           const upb_fielddef *f,
-                           VALUE type_class,
-                           int depth,
-                           upb_sink *sink,
-                           bool emit_defaults,
+static void put_ruby_value(VALUE value, const upb_fielddef* f, VALUE type_class,
+                           int depth, upb_sink sink, bool emit_defaults,
                            bool is_json) {
   if (depth > ENCODE_MAX_NESTING) {
     rb_raise(rb_eRuntimeError,
@@ -1109,8 +1065,8 @@
   }
 }
 
-static void putmap(VALUE map, const upb_fielddef *f, upb_sink *sink,
-                   int depth, bool emit_defaults, bool is_json) {
+static void putmap(VALUE map, const upb_fielddef* f, upb_sink sink, int depth,
+                   bool emit_defaults, bool is_json) {
   Map* self;
   upb_sink subsink;
   const upb_fielddef* key_field;
@@ -1134,17 +1090,17 @@
     upb_status status;
 
     upb_sink entry_sink;
-    upb_sink_startsubmsg(&subsink, getsel(f, UPB_HANDLER_STARTSUBMSG),
+    upb_sink_startsubmsg(subsink, getsel(f, UPB_HANDLER_STARTSUBMSG),
                          &entry_sink);
-    upb_sink_startmsg(&entry_sink);
+    upb_sink_startmsg(entry_sink);
 
-    put_ruby_value(key, key_field, Qnil, depth + 1, &entry_sink,
-                   emit_defaults, is_json);
+    put_ruby_value(key, key_field, Qnil, depth + 1, entry_sink, emit_defaults,
+                   is_json);
     put_ruby_value(value, value_field, self->value_type_class, depth + 1,
-                   &entry_sink, emit_defaults, is_json);
+                   entry_sink, emit_defaults, is_json);
 
-    upb_sink_endmsg(&entry_sink, &status);
-    upb_sink_endsubmsg(&subsink, getsel(f, UPB_HANDLER_ENDSUBMSG));
+    upb_sink_endmsg(entry_sink, &status);
+    upb_sink_endsubmsg(subsink, getsel(f, UPB_HANDLER_ENDSUBMSG));
   }
 
   upb_sink_endseq(sink, getsel(f, UPB_HANDLER_ENDSEQ));
@@ -1153,8 +1109,8 @@
 static const upb_handlers* msgdef_json_serialize_handlers(
     Descriptor* desc, bool preserve_proto_fieldnames);
 
-static void putjsonany(VALUE msg_rb, const Descriptor* desc,
-                       upb_sink* sink, int depth, bool emit_defaults) {
+static void putjsonany(VALUE msg_rb, const Descriptor* desc, upb_sink sink,
+                       int depth, bool emit_defaults) {
   upb_status status;
   MessageHeader* msg = NULL;
   const upb_fielddef* type_field = upb_msgdef_itof(desc->msgdef, UPB_ANY_TYPE);
@@ -1210,7 +1166,7 @@
     value_len = RSTRING_LEN(value_str_rb);
 
     if (value_len > 0) {
-      VALUE payload_desc_rb = get_def_obj(payload_type);
+      VALUE payload_desc_rb = get_msgdef_obj(generated_pool, payload_type);
       Descriptor* payload_desc = ruby_to_Descriptor(payload_desc_rb);
       VALUE payload_class = Descriptor_msgclass(payload_desc_rb);
       upb_sink subsink;
@@ -1228,8 +1184,8 @@
 
       subsink.handlers =
           msgdef_json_serialize_handlers(payload_desc, true);
-      subsink.closure = sink->closure;
-      putmsg(payload_msg_rb, payload_desc, &subsink, depth, emit_defaults, true,
+      subsink.closure = sink.closure;
+      putmsg(payload_msg_rb, payload_desc, subsink, depth, emit_defaults, true,
              is_wellknown);
     }
   }
@@ -1237,9 +1193,8 @@
   upb_sink_endmsg(sink, &status);
 }
 
-static void putmsg(VALUE msg_rb, const Descriptor* desc,
-                   upb_sink *sink, int depth, bool emit_defaults,
-                   bool is_json, bool open_msg) {
+static void putmsg(VALUE msg_rb, const Descriptor* desc, upb_sink sink,
+                   int depth, bool emit_defaults, bool is_json, bool open_msg) {
   MessageHeader* msg;
   upb_msg_field_iter i;
   upb_status status;
@@ -1322,20 +1277,19 @@
     } else {
       upb_selector_t sel = getsel(f, upb_handlers_getprimitivehandlertype(f));
 
-#define T(upbtypeconst, upbtype, ctype, default_value)                          \
-  case upbtypeconst: {                                                          \
-      ctype value = DEREF(msg, offset, ctype);                                  \
-      bool is_default = false;                                                  \
-      if (upb_fielddef_haspresence(f)) {                                        \
-        is_default = layout_has(desc->layout, Message_data(msg), f) == Qfalse;  \
-      } else if (upb_msgdef_syntax(desc->msgdef) == UPB_SYNTAX_PROTO3) {        \
-        is_default = default_value == value;                                    \
-      }                                                                         \
-      if (is_matching_oneof || emit_defaults || !is_default) {                  \
-        upb_sink_put##upbtype(sink, sel, value);                                \
-      }                                                                         \
-    }                                                                           \
-    break;
+#define T(upbtypeconst, upbtype, ctype, default_value)                       \
+  case upbtypeconst: {                                                       \
+    ctype value = DEREF(msg, offset, ctype);                                 \
+    bool is_default = false;                                                 \
+    if (upb_fielddef_haspresence(f)) {                                       \
+      is_default = layout_has(desc->layout, Message_data(msg), f) == Qfalse; \
+    } else if (upb_msgdef_syntax(desc->msgdef) == UPB_SYNTAX_PROTO3) {       \
+      is_default = default_value == value;                                   \
+    }                                                                        \
+    if (is_matching_oneof || emit_defaults || !is_default) {                 \
+      upb_sink_put##upbtype(sink, sel, value);                               \
+    }                                                                        \
+  } break;
 
       switch (upb_fielddef_type(f)) {
         T(UPB_TYPE_FLOAT,  float,  float, 0.0)
@@ -1367,33 +1321,6 @@
   }
 }
 
-static const upb_handlers* msgdef_pb_serialize_handlers(Descriptor* desc) {
-  if (desc->pb_serialize_handlers == NULL) {
-    desc->pb_serialize_handlers =
-        upb_pb_encoder_newhandlers(desc->msgdef, &desc->pb_serialize_handlers);
-  }
-  return desc->pb_serialize_handlers;
-}
-
-static const upb_handlers* msgdef_json_serialize_handlers(
-    Descriptor* desc, bool preserve_proto_fieldnames) {
-  if (preserve_proto_fieldnames) {
-    if (desc->json_serialize_handlers == NULL) {
-      desc->json_serialize_handlers =
-          upb_json_printer_newhandlers(
-              desc->msgdef, true, &desc->json_serialize_handlers);
-    }
-    return desc->json_serialize_handlers;
-  } else {
-    if (desc->json_serialize_handlers_preserve == NULL) {
-      desc->json_serialize_handlers_preserve =
-          upb_json_printer_newhandlers(
-              desc->msgdef, false, &desc->json_serialize_handlers_preserve);
-    }
-    return desc->json_serialize_handlers_preserve;
-  }
-}
-
 /*
  * call-seq:
  *     MessageClass.encode(msg) => bytes
@@ -1416,8 +1343,8 @@
     upb_pb_encoder* encoder;
     VALUE ret;
 
-    stackenv_init(&se, "Error occurred during encoding: %s");
-    encoder = upb_pb_encoder_create(&se.env, serialize_handlers, &sink.sink);
+    stackenv_init(&se, "Error occurred during encoding: %" PRIsVALUE);
+    encoder = upb_pb_encoder_create(se.arena, serialize_handlers, sink.sink);
 
     putmsg(msg_rb, desc, upb_pb_encoder_input(encoder), 0, false, false, true);
 
@@ -1474,8 +1401,8 @@
     stackenv se;
     VALUE ret;
 
-    stackenv_init(&se, "Error occurred during encoding: %s");
-    printer = upb_json_printer_create(&se.env, serialize_handlers, &sink.sink);
+    stackenv_init(&se, "Error occurred during encoding: %" PRIsVALUE);
+    printer = upb_json_printer_create(se.arena, serialize_handlers, sink.sink);
 
     putmsg(msg_rb, desc, upb_json_printer_input(printer), 0,
            RTEST(emit_defaults), true, true);
diff --git a/ruby/ext/google/protobuf_c/message.c b/ruby/ext/google/protobuf_c/message.c
index 5537b38..51bee24 100644
--- a/ruby/ext/google/protobuf_c/message.c
+++ b/ruby/ext/google/protobuf_c/message.c
@@ -60,6 +60,11 @@
 VALUE Message_alloc(VALUE klass) {
   VALUE descriptor = rb_ivar_get(klass, descriptor_instancevar_interned);
   Descriptor* desc = ruby_to_Descriptor(descriptor);
+
+  if (desc->layout == NULL) {
+    desc->layout = create_layout(desc);
+  }
+
   MessageHeader* msg = (MessageHeader*)ALLOC_N(
       uint8_t, sizeof(MessageHeader) + desc->layout->size);
   VALUE ret;
@@ -276,7 +281,7 @@
   } else if (accessor_type == METHOD_PRESENCE) {
     return layout_has(self->descriptor->layout, Message_data(self), f);
   } else if (accessor_type == METHOD_ENUM_GETTER) {
-    VALUE enum_type = field_type_class(f);
+    VALUE enum_type = field_type_class(self->descriptor->layout, f);
     VALUE method = rb_intern("const_get");
     VALUE raw_value = layout_get(self->descriptor->layout, Message_data(self), f);
 
@@ -320,15 +325,13 @@
   }
 }
 
-VALUE create_submsg_from_hash(const upb_fielddef *f, VALUE hash) {
-  const upb_def *d = upb_fielddef_subdef(f);
+VALUE create_submsg_from_hash(const MessageLayout* layout,
+                              const upb_fielddef* f, VALUE hash) {
+  const upb_msgdef *d = upb_fielddef_msgsubdef(f);
   assert(d != NULL);
 
-  VALUE descriptor = get_def_obj(d);
-  VALUE msgclass = rb_funcall(descriptor, rb_intern("msgclass"), 0, NULL);
-
   VALUE args[1] = { hash };
-  return rb_class_new_instance(1, args, msgclass);
+  return rb_class_new_instance(1, args, field_type_class(layout, f));
 }
 
 int Message_initialize_kwarg(VALUE key, VALUE val, VALUE _self) {
@@ -378,14 +381,14 @@
     for (int i = 0; i < RARRAY_LEN(val); i++) {
       VALUE entry = rb_ary_entry(val, i);
       if (TYPE(entry) == T_HASH && upb_fielddef_issubmsg(f)) {
-        entry = create_submsg_from_hash(f, entry);
+        entry = create_submsg_from_hash(self->descriptor->layout, f, entry);
       }
 
       RepeatedField_push(ary, entry);
     }
   } else {
     if (TYPE(val) == T_HASH && upb_fielddef_issubmsg(f)) {
-      val = create_submsg_from_hash(f, val);
+      val = create_submsg_from_hash(self->descriptor->layout, f, val);
     }
 
     layout_set(self->descriptor->layout, Message_data(self), f, val);
@@ -630,17 +633,11 @@
   return rb_ivar_get(klass, descriptor_instancevar_interned);
 }
 
-VALUE build_class_from_descriptor(Descriptor* desc) {
+VALUE build_class_from_descriptor(VALUE descriptor) {
+  Descriptor* desc = ruby_to_Descriptor(descriptor);
   const char *name;
   VALUE klass;
 
-  if (desc->layout == NULL) {
-    desc->layout = create_layout(desc->msgdef);
-  }
-  if (desc->fill_method == NULL) {
-    desc->fill_method = new_fillmsg_decodermethod(desc, &desc->fill_method);
-  }
-
   name = upb_msgdef_fullname(desc->msgdef);
   if (name == NULL) {
     rb_raise(rb_eRuntimeError, "Descriptor does not have assigned name.");
@@ -651,8 +648,7 @@
       // their own toplevel constant class name.
       rb_intern("Message"),
       rb_cObject);
-  rb_ivar_set(klass, descriptor_instancevar_interned,
-              get_def_obj(desc->msgdef));
+  rb_ivar_set(klass, descriptor_instancevar_interned, descriptor);
   rb_define_alloc_func(klass, Message_alloc);
   rb_require("google/protobuf/message_exts");
   rb_include_module(klass, rb_eval_string("::Google::Protobuf::MessageExts"));
@@ -737,7 +733,8 @@
   return rb_ivar_get(self, descriptor_instancevar_interned);
 }
 
-VALUE build_module_from_enumdesc(EnumDescriptor* enumdesc) {
+VALUE build_module_from_enumdesc(VALUE _enumdesc) {
+  EnumDescriptor* enumdesc = ruby_to_EnumDescriptor(_enumdesc);
   VALUE mod = rb_define_module_id(
       rb_intern(upb_enumdef_fullname(enumdesc->enumdef)));
 
@@ -758,8 +755,7 @@
   rb_define_singleton_method(mod, "lookup", enum_lookup, 1);
   rb_define_singleton_method(mod, "resolve", enum_resolve, 1);
   rb_define_singleton_method(mod, "descriptor", enum_descriptor, 0);
-  rb_ivar_set(mod, descriptor_instancevar_interned,
-              get_def_obj(enumdesc->enumdef));
+  rb_ivar_set(mod, descriptor_instancevar_interned, _enumdesc);
 
   return mod;
 }
diff --git a/ruby/ext/google/protobuf_c/protobuf.c b/ruby/ext/google/protobuf_c/protobuf.c
index fd964c7..9ec0558 100644
--- a/ruby/ext/google/protobuf_c/protobuf.c
+++ b/ruby/ext/google/protobuf_c/protobuf.c
@@ -30,26 +30,10 @@
 
 #include "protobuf.h"
 
-// -----------------------------------------------------------------------------
-// Global map from upb {msg,enum}defs to wrapper Descriptor/EnumDescriptor
-// instances.
-// -----------------------------------------------------------------------------
-
-// This is a hash table from def objects (encoded by converting pointers to
-// Ruby integers) to MessageDef/EnumDef instances (as Ruby values).
-VALUE upb_def_to_ruby_obj_map;
-
 VALUE cError;
 VALUE cParseError;
 VALUE cTypeError;
-
-void add_def_obj(const void* def, VALUE value) {
-  rb_hash_aset(upb_def_to_ruby_obj_map, ULL2NUM((intptr_t)def), value);
-}
-
-VALUE get_def_obj(const void* def) {
-  return rb_hash_aref(upb_def_to_ruby_obj_map, ULL2NUM((intptr_t)def));
-}
+VALUE c_only_cookie;
 
 // -----------------------------------------------------------------------------
 // Utilities.
@@ -116,6 +100,6 @@
   kRubyStringASCIIEncoding = rb_usascii_encoding();
   kRubyString8bitEncoding = rb_ascii8bit_encoding();
 
-  rb_gc_register_address(&upb_def_to_ruby_obj_map);
-  upb_def_to_ruby_obj_map = rb_hash_new();
+  rb_gc_register_address(&c_only_cookie);
+  c_only_cookie = rb_class_new_instance(0, NULL, rb_cObject);
 }
diff --git a/ruby/ext/google/protobuf_c/protobuf.h b/ruby/ext/google/protobuf_c/protobuf.h
index 8731eeb..f58a2e7 100644
--- a/ruby/ext/google/protobuf_c/protobuf.h
+++ b/ruby/ext/google/protobuf_c/protobuf.h
@@ -107,62 +107,68 @@
 // -----------------------------------------------------------------------------
 
 struct DescriptorPool {
+  VALUE def_to_descriptor;  // Hash table of def* -> Ruby descriptor.
   upb_symtab* symtab;
+  upb_handlercache* fill_handler_cache;
+  upb_handlercache* pb_serialize_handler_cache;
+  upb_handlercache* json_serialize_handler_cache;
+  upb_handlercache* json_serialize_handler_preserve_cache;
+  upb_pbcodecache* fill_method_cache;
+  upb_json_codecache* json_fill_method_cache;
 };
 
 struct Descriptor {
   const upb_msgdef* msgdef;
   MessageLayout* layout;
-  VALUE klass;  // begins as nil
-  const upb_handlers* fill_handlers;
-  const upb_pbdecodermethod* fill_method;
-  const upb_json_parsermethod* json_fill_method;
-  const upb_handlers* pb_serialize_handlers;
-  const upb_handlers* json_serialize_handlers;
-  const upb_handlers* json_serialize_handlers_preserve;
+  VALUE klass;
+  VALUE descriptor_pool;
 };
 
 struct FileDescriptor {
   const upb_filedef* filedef;
+  VALUE descriptor_pool;  // Owns the upb_filedef.
 };
 
 struct FieldDescriptor {
   const upb_fielddef* fielddef;
+  VALUE descriptor_pool;  // Owns the upb_fielddef.
 };
 
 struct OneofDescriptor {
   const upb_oneofdef* oneofdef;
+  VALUE descriptor_pool;  // Owns the upb_oneofdef.
 };
 
 struct EnumDescriptor {
   const upb_enumdef* enumdef;
   VALUE module;  // begins as nil
+  VALUE descriptor_pool;  // Owns the upb_enumdef.
 };
 
 struct MessageBuilderContext {
-  VALUE descriptor;
-  VALUE builder;
+  google_protobuf_DescriptorProto* msg_proto;
+  VALUE file_builder;
 };
 
 struct OneofBuilderContext {
-  VALUE descriptor;
-  VALUE builder;
+  int oneof_index;
+  VALUE message_builder;
 };
 
 struct EnumBuilderContext {
-  VALUE enumdesc;
+  google_protobuf_EnumDescriptorProto* enum_proto;
+  VALUE file_builder;
 };
 
 struct FileBuilderContext {
-  VALUE pending_list;
-  VALUE file_descriptor;
-  VALUE builder;
+  upb_arena *arena;
+  google_protobuf_FileDescriptorProto* file_proto;
+  VALUE descriptor_pool;
 };
 
 struct Builder {
-  VALUE pending_list;
-  VALUE default_file_descriptor;
-  upb_def** defs;  // used only while finalizing
+  VALUE descriptor_pool;
+  VALUE default_file_builder;
 };
 
 extern VALUE cDescriptorPool;
@@ -191,7 +197,6 @@
 VALUE DescriptorPool_alloc(VALUE klass);
 void DescriptorPool_register(VALUE module);
 DescriptorPool* ruby_to_DescriptorPool(VALUE value);
-VALUE DescriptorPool_add(VALUE _self, VALUE def);
 VALUE DescriptorPool_build(int argc, VALUE* argv, VALUE _self);
 VALUE DescriptorPool_lookup(VALUE _self, VALUE name);
 VALUE DescriptorPool_generated_pool(VALUE _self);
@@ -203,13 +208,11 @@
 VALUE Descriptor_alloc(VALUE klass);
 void Descriptor_register(VALUE module);
 Descriptor* ruby_to_Descriptor(VALUE value);
-VALUE Descriptor_initialize(VALUE _self, VALUE file_descriptor_rb);
+VALUE Descriptor_initialize(VALUE _self, VALUE cookie, VALUE descriptor_pool,
+                            VALUE ptr);
 VALUE Descriptor_name(VALUE _self);
-VALUE Descriptor_name_set(VALUE _self, VALUE str);
 VALUE Descriptor_each(VALUE _self);
 VALUE Descriptor_lookup(VALUE _self, VALUE name);
-VALUE Descriptor_add_field(VALUE _self, VALUE obj);
-VALUE Descriptor_add_oneof(VALUE _self, VALUE obj);
 VALUE Descriptor_each_oneof(VALUE _self);
 VALUE Descriptor_lookup_oneof(VALUE _self, VALUE name);
 VALUE Descriptor_msgclass(VALUE _self);
@@ -221,28 +224,24 @@
 VALUE FileDescriptor_alloc(VALUE klass);
 void FileDescriptor_register(VALUE module);
 FileDescriptor* ruby_to_FileDescriptor(VALUE value);
-VALUE FileDescriptor_initialize(int argc, VALUE* argv, VALUE _self);
+VALUE FileDescriptor_initialize(VALUE _self, VALUE cookie,
+                                VALUE descriptor_pool, VALUE ptr);
 VALUE FileDescriptor_name(VALUE _self);
 VALUE FileDescriptor_syntax(VALUE _self);
-VALUE FileDescriptor_syntax_set(VALUE _self, VALUE syntax);
 
 void FieldDescriptor_mark(void* _self);
 void FieldDescriptor_free(void* _self);
 VALUE FieldDescriptor_alloc(VALUE klass);
 void FieldDescriptor_register(VALUE module);
 FieldDescriptor* ruby_to_FieldDescriptor(VALUE value);
+VALUE FieldDescriptor_initialize(VALUE _self, VALUE cookie,
+                                 VALUE descriptor_pool, VALUE ptr);
 VALUE FieldDescriptor_name(VALUE _self);
-VALUE FieldDescriptor_name_set(VALUE _self, VALUE str);
 VALUE FieldDescriptor_type(VALUE _self);
-VALUE FieldDescriptor_type_set(VALUE _self, VALUE type);
 VALUE FieldDescriptor_default(VALUE _self);
-VALUE FieldDescriptor_default_set(VALUE _self, VALUE default_value);
 VALUE FieldDescriptor_label(VALUE _self);
-VALUE FieldDescriptor_label_set(VALUE _self, VALUE label);
 VALUE FieldDescriptor_number(VALUE _self);
-VALUE FieldDescriptor_number_set(VALUE _self, VALUE number);
 VALUE FieldDescriptor_submsg_name(VALUE _self);
-VALUE FieldDescriptor_submsg_name_set(VALUE _self, VALUE value);
 VALUE FieldDescriptor_subtype(VALUE _self);
 VALUE FieldDescriptor_has(VALUE _self, VALUE msg_rb);
 VALUE FieldDescriptor_clear(VALUE _self, VALUE msg_rb);
@@ -256,21 +255,20 @@
 VALUE OneofDescriptor_alloc(VALUE klass);
 void OneofDescriptor_register(VALUE module);
 OneofDescriptor* ruby_to_OneofDescriptor(VALUE value);
+VALUE OneofDescriptor_initialize(VALUE _self, VALUE cookie,
+                                 VALUE descriptor_pool, VALUE ptr);
 VALUE OneofDescriptor_name(VALUE _self);
-VALUE OneofDescriptor_name_set(VALUE _self, VALUE value);
-VALUE OneofDescriptor_add_field(VALUE _self, VALUE field);
 VALUE OneofDescriptor_each(VALUE _self, VALUE field);
 
 void EnumDescriptor_mark(void* _self);
 void EnumDescriptor_free(void* _self);
 VALUE EnumDescriptor_alloc(VALUE klass);
+VALUE EnumDescriptor_initialize(VALUE _self, VALUE cookie,
+                                VALUE descriptor_pool, VALUE ptr);
 void EnumDescriptor_register(VALUE module);
 EnumDescriptor* ruby_to_EnumDescriptor(VALUE value);
-VALUE EnumDescriptor_initialize(VALUE _self, VALUE file_descriptor_rb);
 VALUE EnumDescriptor_file_descriptor(VALUE _self);
 VALUE EnumDescriptor_name(VALUE _self);
-VALUE EnumDescriptor_name_set(VALUE _self, VALUE str);
-VALUE EnumDescriptor_add_value(VALUE _self, VALUE name, VALUE number);
 VALUE EnumDescriptor_lookup_name(VALUE _self, VALUE name);
 VALUE EnumDescriptor_lookup_value(VALUE _self, VALUE number);
 VALUE EnumDescriptor_each(VALUE _self);
@@ -283,8 +281,8 @@
 void MessageBuilderContext_register(VALUE module);
 MessageBuilderContext* ruby_to_MessageBuilderContext(VALUE value);
 VALUE MessageBuilderContext_initialize(VALUE _self,
-                                       VALUE descriptor,
-                                       VALUE builder);
+                                       VALUE _file_builder,
+                                       VALUE name);
 VALUE MessageBuilderContext_optional(int argc, VALUE* argv, VALUE _self);
 VALUE MessageBuilderContext_required(int argc, VALUE* argv, VALUE _self);
 VALUE MessageBuilderContext_repeated(int argc, VALUE* argv, VALUE _self);
@@ -306,15 +304,19 @@
 VALUE EnumBuilderContext_alloc(VALUE klass);
 void EnumBuilderContext_register(VALUE module);
 EnumBuilderContext* ruby_to_EnumBuilderContext(VALUE value);
-VALUE EnumBuilderContext_initialize(VALUE _self, VALUE enumdesc);
+VALUE EnumBuilderContext_initialize(VALUE _self, VALUE _file_builder,
+                                    VALUE name);
 VALUE EnumBuilderContext_value(VALUE _self, VALUE name, VALUE number);
 
 void FileBuilderContext_mark(void* _self);
 void FileBuilderContext_free(void* _self);
 VALUE FileBuilderContext_alloc(VALUE klass);
 void FileBuilderContext_register(VALUE module);
-VALUE FileBuilderContext_initialize(VALUE _self, VALUE file_descriptor,
-				    VALUE builder);
+FileBuilderContext* ruby_to_FileBuilderContext(VALUE _self);
+upb_strview FileBuilderContext_strdup(VALUE _self, VALUE rb_str);
+upb_strview FileBuilderContext_strdup_name(VALUE _self, VALUE rb_str);
+VALUE FileBuilderContext_initialize(VALUE _self, VALUE descriptor_pool,
+                                    VALUE name, VALUE options);
 VALUE FileBuilderContext_add_message(VALUE _self, VALUE name);
 VALUE FileBuilderContext_add_enum(VALUE _self, VALUE name);
 VALUE FileBuilderContext_pending_descriptors(VALUE _self);
@@ -324,7 +326,8 @@
 VALUE Builder_alloc(VALUE klass);
 void Builder_register(VALUE module);
 Builder* ruby_to_Builder(VALUE value);
-VALUE Builder_initialize(VALUE _self);
+VALUE Builder_build(VALUE _self);
+VALUE Builder_initialize(VALUE _self, VALUE descriptor_pool);
 VALUE Builder_add_file(int argc, VALUE *argv, VALUE _self);
 VALUE Builder_add_message(VALUE _self, VALUE name);
 VALUE Builder_add_enum(VALUE _self, VALUE name);
@@ -368,7 +371,7 @@
 extern rb_encoding* kRubyStringASCIIEncoding;
 extern rb_encoding* kRubyString8bitEncoding;
 
-VALUE field_type_class(const upb_fielddef* field);
+VALUE field_type_class(const MessageLayout* layout, const upb_fielddef* field);
 
 #define MAP_KEY_FIELD 1
 #define MAP_VALUE_FIELD 2
@@ -501,13 +504,15 @@
   size_t hasbit;
 };
 
+// MessageLayout is owned by the enclosing Descriptor, which must outlive us.
 struct MessageLayout {
+  const Descriptor* desc;
   const upb_msgdef* msgdef;
   MessageField* fields;
   size_t size;
 };
 
-MessageLayout* create_layout(const upb_msgdef* msgdef);
+MessageLayout* create_layout(const Descriptor* desc);
 void free_layout(MessageLayout* layout);
 bool field_contains_hasbit(MessageLayout* layout,
                  const upb_fielddef* field);
@@ -556,7 +561,7 @@
 
 extern rb_data_type_t Message_type;
 
-VALUE build_class_from_descriptor(Descriptor* descriptor);
+VALUE build_class_from_descriptor(VALUE descriptor);
 void* Message_data(void* msg);
 void Message_mark(void* self);
 void Message_free(void* self);
@@ -580,12 +585,13 @@
 VALUE Google_Protobuf_discard_unknown(VALUE self, VALUE msg_rb);
 VALUE Google_Protobuf_deep_copy(VALUE self, VALUE obj);
 
-VALUE build_module_from_enumdesc(EnumDescriptor* enumdef);
+VALUE build_module_from_enumdesc(VALUE _enumdesc);
 VALUE enum_lookup(VALUE self, VALUE number);
 VALUE enum_resolve(VALUE self, VALUE sym);
 
 const upb_pbdecodermethod *new_fillmsg_decodermethod(
     Descriptor* descriptor, const void *owner);
+void add_handlers_for_message(const void *closure, upb_handlers *h);
 
 // Maximum depth allowed during encoding, to avoid stack overflows due to
 // cycles.
@@ -595,8 +601,11 @@
 // Global map from upb {msg,enum}defs to wrapper Descriptor/EnumDescriptor
 // instances.
 // -----------------------------------------------------------------------------
-void add_def_obj(const void* def, VALUE value);
-VALUE get_def_obj(const void* def);
+VALUE get_msgdef_obj(VALUE descriptor_pool, const upb_msgdef* def);
+VALUE get_enumdef_obj(VALUE descriptor_pool, const upb_enumdef* def);
+VALUE get_fielddef_obj(VALUE descriptor_pool, const upb_fielddef* def);
+VALUE get_filedef_obj(VALUE descriptor_pool, const upb_filedef* def);
+VALUE get_oneofdef_obj(VALUE descriptor_pool, const upb_oneofdef* def);
 
 // -----------------------------------------------------------------------------
 // Utilities.
@@ -612,4 +621,9 @@
 
 extern ID descriptor_instancevar_interned;
 
+// A distinct object that is not accessible from Ruby.  We use this as a
+// constructor argument to enforce that certain objects cannot be created from
+// Ruby.
+extern VALUE c_only_cookie;
+
 #endif  // __GOOGLE_PROTOBUF_RUBY_PROTOBUF_H__
diff --git a/ruby/ext/google/protobuf_c/storage.c b/ruby/ext/google/protobuf_c/storage.c
index e9fea23..f15d10a 100644
--- a/ruby/ext/google/protobuf_c/storage.c
+++ b/ruby/ext/google/protobuf_c/storage.c
@@ -430,8 +430,10 @@
   return (offset + granularity - 1) & ~(granularity - 1);
 }
 
-MessageLayout* create_layout(const upb_msgdef* msgdef) {
+MessageLayout* create_layout(const Descriptor* desc) {
+  const upb_msgdef *msgdef = desc->msgdef;
   MessageLayout* layout = ALLOC(MessageLayout);
+  layout->desc = desc;
   int nfields = upb_msgdef_numfields(msgdef);
   upb_msg_field_iter it;
   upb_msg_oneof_iter oit;
@@ -448,7 +450,7 @@
       layout->fields[upb_fielddef_index(field)].hasbit = hasbit++;
     } else {
       layout->fields[upb_fielddef_index(field)].hasbit =
-	  MESSAGE_FIELD_NO_HASBIT;
+          MESSAGE_FIELD_NO_HASBIT;
     }
   }
 
@@ -537,28 +539,25 @@
   }
 
   layout->size = off;
-
   layout->msgdef = msgdef;
-  upb_msgdef_ref(layout->msgdef, &layout->msgdef);
 
   return layout;
 }
 
 void free_layout(MessageLayout* layout) {
   xfree(layout->fields);
-  upb_msgdef_unref(layout->msgdef, &layout->msgdef);
   xfree(layout);
 }
 
-VALUE field_type_class(const upb_fielddef* field) {
+VALUE field_type_class(const MessageLayout* layout, const upb_fielddef* field) {
   VALUE type_class = Qnil;
   if (upb_fielddef_type(field) == UPB_TYPE_MESSAGE) {
-    VALUE submsgdesc =
-        get_def_obj(upb_fielddef_subdef(field));
+    VALUE submsgdesc = get_msgdef_obj(layout->desc->descriptor_pool,
+                                      upb_fielddef_msgsubdef(field));
     type_class = Descriptor_msgclass(submsgdesc);
   } else if (upb_fielddef_type(field) == UPB_TYPE_ENUM) {
-    VALUE subenumdesc =
-        get_def_obj(upb_fielddef_subdef(field));
+    VALUE subenumdesc = get_enumdef_obj(layout->desc->descriptor_pool,
+                                        upb_fielddef_enumsubdef(field));
     type_class = EnumDescriptor_enummodule(subenumdesc);
   }
   return type_class;
@@ -632,7 +631,7 @@
 
     const upb_fielddef* key_field = map_field_key(field);
     const upb_fielddef* value_field = map_field_value(field);
-    VALUE type_class = field_type_class(value_field);
+    VALUE type_class = field_type_class(layout, value_field);
 
     if (type_class != Qnil) {
       VALUE args[3] = {
@@ -653,7 +652,7 @@
   } else if (upb_fielddef_label(field) == UPB_LABEL_REPEATED) {
     VALUE ary = Qnil;
 
-    VALUE type_class = field_type_class(field);
+    VALUE type_class = field_type_class(layout, field);
 
     if (type_class != Qnil) {
       VALUE args[2] = {
@@ -668,9 +667,9 @@
 
     DEREF(memory, VALUE) = ary;
   } else {
-    native_slot_set(upb_fielddef_name(field),
-                    upb_fielddef_type(field), field_type_class(field),
-                    memory, layout_get_default(field));
+    native_slot_set(upb_fielddef_name(field), upb_fielddef_type(field),
+                    field_type_class(layout, field), memory,
+                    layout_get_default(field));
   }
 }
 
@@ -728,20 +727,19 @@
       return layout_get_default(field);
     }
     return native_slot_get(upb_fielddef_type(field),
-                           field_type_class(field),
-                           memory);
+                           field_type_class(layout, field), memory);
   } else if (upb_fielddef_label(field) == UPB_LABEL_REPEATED) {
     return *((VALUE *)memory);
   } else if (!field_set) {
     return layout_get_default(field);
   } else {
     return native_slot_get(upb_fielddef_type(field),
-                           field_type_class(field),
-                           memory);
+                           field_type_class(layout, field), memory);
   }
 }
 
-static void check_repeated_field_type(VALUE val, const upb_fielddef* field) {
+static void check_repeated_field_type(const MessageLayout* layout, VALUE val,
+                                      const upb_fielddef* field) {
   RepeatedField* self;
   assert(upb_fielddef_label(field) == UPB_LABEL_REPEATED);
 
@@ -755,25 +753,13 @@
     rb_raise(cTypeError, "Repeated field array has wrong element type");
   }
 
-  if (self->field_type == UPB_TYPE_MESSAGE) {
-    if (self->field_type_class !=
-        Descriptor_msgclass(get_def_obj(upb_fielddef_subdef(field)))) {
-      rb_raise(cTypeError,
-               "Repeated field array has wrong message class");
-    }
-  }
-
-
-  if (self->field_type == UPB_TYPE_ENUM) {
-    if (self->field_type_class !=
-        EnumDescriptor_enummodule(get_def_obj(upb_fielddef_subdef(field)))) {
-      rb_raise(cTypeError,
-               "Repeated field array has wrong enum class");
-    }
+  if (self->field_type_class != field_type_class(layout, field)) {
+    rb_raise(cTypeError, "Repeated field array has wrong message/enum class");
   }
 }
 
-static void check_map_field_type(VALUE val, const upb_fielddef* field) {
+static void check_map_field_type(const MessageLayout* layout, VALUE val,
+                                 const upb_fielddef* field) {
   const upb_fielddef* key_field = map_field_key(field);
   const upb_fielddef* value_field = map_field_value(field);
   Map* self;
@@ -790,17 +776,11 @@
   if (self->value_type != upb_fielddef_type(value_field)) {
     rb_raise(cTypeError, "Map value type does not match field's value type");
   }
-  if (upb_fielddef_type(value_field) == UPB_TYPE_MESSAGE ||
-      upb_fielddef_type(value_field) == UPB_TYPE_ENUM) {
-    if (self->value_type_class !=
-        get_def_obj(upb_fielddef_subdef(value_field))) {
-      rb_raise(cTypeError,
-               "Map value type has wrong message/enum class");
-    }
+  if (self->value_type_class != field_type_class(layout, value_field)) {
+    rb_raise(cTypeError, "Map value type has wrong message/enum class");
   }
 }
 
-
 void layout_set(MessageLayout* layout,
                 void* storage,
                 const upb_fielddef* field,
@@ -828,20 +808,19 @@
       // and case number are altered atomically (w.r.t. the Ruby VM).
       native_slot_set_value_and_case(
           upb_fielddef_name(field),
-          upb_fielddef_type(field), field_type_class(field),
+          upb_fielddef_type(field), field_type_class(layout, field),
           memory, val,
           oneof_case, upb_fielddef_number(field));
     }
   } else if (is_map_field(field)) {
-    check_map_field_type(val, field);
+    check_map_field_type(layout, val, field);
     DEREF(memory, VALUE) = val;
   } else if (upb_fielddef_label(field) == UPB_LABEL_REPEATED) {
-    check_repeated_field_type(val, field);
+    check_repeated_field_type(layout, val, field);
     DEREF(memory, VALUE) = val;
   } else {
-    native_slot_set(upb_fielddef_name(field),
-                    upb_fielddef_type(field), field_type_class(field),
-                    memory, val);
+    native_slot_set(upb_fielddef_name(field), upb_fielddef_type(field),
+                    field_type_class(layout, field), memory, val);
   }
 
   if (layout->fields[upb_fielddef_index(field)].hasbit !=
diff --git a/ruby/ext/google/protobuf_c/upb.c b/ruby/ext/google/protobuf_c/upb.c
index 079c28b..9385da7 100644
--- a/ruby/ext/google/protobuf_c/upb.c
+++ b/ruby/ext/google/protobuf_c/upb.c
@@ -1,6 +1,11 @@
-// Amalgamated source file
+/* Amalgamated source file */
+#define _XOPEN_SOURCE 700
 #include "upb.h"
 
+#ifndef UINTPTR_MAX
+#error must include stdint.h first
+#endif
+
 #if UINTPTR_MAX == 0xffffffff
 #define UPB_SIZE(size32, size64) size32
 #else
@@ -53,24 +58,24 @@
 };
 
 static const upb_msglayout_field google_protobuf_FileDescriptorProto__fields[12] = {
-  {1, UPB_SIZE(8, 16), 1, 0, 9, 1},
-  {2, UPB_SIZE(16, 32), 2, 0, 9, 1},
-  {3, UPB_SIZE(40, 80), 0, 0, 9, 3},
-  {4, UPB_SIZE(44, 88), 0, 0, 11, 3},
-  {5, UPB_SIZE(48, 96), 0, 1, 11, 3},
-  {6, UPB_SIZE(52, 104), 0, 4, 11, 3},
-  {7, UPB_SIZE(56, 112), 0, 2, 11, 3},
-  {8, UPB_SIZE(32, 64), 4, 3, 11, 1},
-  {9, UPB_SIZE(36, 72), 5, 5, 11, 1},
-  {10, UPB_SIZE(60, 120), 0, 0, 5, 3},
-  {11, UPB_SIZE(64, 128), 0, 0, 5, 3},
-  {12, UPB_SIZE(24, 48), 3, 0, 9, 1},
+  {1, UPB_SIZE(4, 8), 1, 0, 9, 1},
+  {2, UPB_SIZE(12, 24), 2, 0, 9, 1},
+  {3, UPB_SIZE(36, 72), 0, 0, 9, 3},
+  {4, UPB_SIZE(40, 80), 0, 0, 11, 3},
+  {5, UPB_SIZE(44, 88), 0, 1, 11, 3},
+  {6, UPB_SIZE(48, 96), 0, 4, 11, 3},
+  {7, UPB_SIZE(52, 104), 0, 2, 11, 3},
+  {8, UPB_SIZE(28, 56), 4, 3, 11, 1},
+  {9, UPB_SIZE(32, 64), 5, 5, 11, 1},
+  {10, UPB_SIZE(56, 112), 0, 0, 5, 3},
+  {11, UPB_SIZE(60, 120), 0, 0, 5, 3},
+  {12, UPB_SIZE(20, 40), 3, 0, 9, 1},
 };
 
 const upb_msglayout google_protobuf_FileDescriptorProto_msginit = {
   &google_protobuf_FileDescriptorProto_submsgs[0],
   &google_protobuf_FileDescriptorProto__fields[0],
-  UPB_SIZE(72, 144), 12, false,
+  UPB_SIZE(64, 128), 12, false,
 };
 
 static const upb_msglayout *const google_protobuf_DescriptorProto_submsgs[8] = {
@@ -84,22 +89,22 @@
 };
 
 static const upb_msglayout_field google_protobuf_DescriptorProto__fields[10] = {
-  {1, UPB_SIZE(8, 16), 1, 0, 9, 1},
-  {2, UPB_SIZE(20, 40), 0, 4, 11, 3},
-  {3, UPB_SIZE(24, 48), 0, 0, 11, 3},
-  {4, UPB_SIZE(28, 56), 0, 3, 11, 3},
-  {5, UPB_SIZE(32, 64), 0, 1, 11, 3},
-  {6, UPB_SIZE(36, 72), 0, 4, 11, 3},
-  {7, UPB_SIZE(16, 32), 2, 5, 11, 1},
-  {8, UPB_SIZE(40, 80), 0, 6, 11, 3},
-  {9, UPB_SIZE(44, 88), 0, 2, 11, 3},
-  {10, UPB_SIZE(48, 96), 0, 0, 9, 3},
+  {1, UPB_SIZE(4, 8), 1, 0, 9, 1},
+  {2, UPB_SIZE(16, 32), 0, 4, 11, 3},
+  {3, UPB_SIZE(20, 40), 0, 0, 11, 3},
+  {4, UPB_SIZE(24, 48), 0, 3, 11, 3},
+  {5, UPB_SIZE(28, 56), 0, 1, 11, 3},
+  {6, UPB_SIZE(32, 64), 0, 4, 11, 3},
+  {7, UPB_SIZE(12, 24), 2, 5, 11, 1},
+  {8, UPB_SIZE(36, 72), 0, 6, 11, 3},
+  {9, UPB_SIZE(40, 80), 0, 2, 11, 3},
+  {10, UPB_SIZE(44, 88), 0, 0, 9, 3},
 };
 
 const upb_msglayout google_protobuf_DescriptorProto_msginit = {
   &google_protobuf_DescriptorProto_submsgs[0],
   &google_protobuf_DescriptorProto__fields[0],
-  UPB_SIZE(56, 112), 10, false,
+  UPB_SIZE(48, 96), 10, false,
 };
 
 static const upb_msglayout *const google_protobuf_DescriptorProto_ExtensionRange_submsgs[1] = {
@@ -171,14 +176,14 @@
 };
 
 static const upb_msglayout_field google_protobuf_OneofDescriptorProto__fields[2] = {
-  {1, UPB_SIZE(8, 16), 1, 0, 9, 1},
-  {2, UPB_SIZE(16, 32), 2, 0, 11, 1},
+  {1, UPB_SIZE(4, 8), 1, 0, 9, 1},
+  {2, UPB_SIZE(12, 24), 2, 0, 11, 1},
 };
 
 const upb_msglayout google_protobuf_OneofDescriptorProto_msginit = {
   &google_protobuf_OneofDescriptorProto_submsgs[0],
   &google_protobuf_OneofDescriptorProto__fields[0],
-  UPB_SIZE(24, 48), 2, false,
+  UPB_SIZE(16, 32), 2, false,
 };
 
 static const upb_msglayout *const google_protobuf_EnumDescriptorProto_submsgs[3] = {
@@ -188,11 +193,11 @@
 };
 
 static const upb_msglayout_field google_protobuf_EnumDescriptorProto__fields[5] = {
-  {1, UPB_SIZE(8, 16), 1, 0, 9, 1},
-  {2, UPB_SIZE(20, 40), 0, 2, 11, 3},
-  {3, UPB_SIZE(16, 32), 2, 1, 11, 1},
-  {4, UPB_SIZE(24, 48), 0, 0, 11, 3},
-  {5, UPB_SIZE(28, 56), 0, 0, 9, 3},
+  {1, UPB_SIZE(4, 8), 1, 0, 9, 1},
+  {2, UPB_SIZE(16, 32), 0, 2, 11, 3},
+  {3, UPB_SIZE(12, 24), 2, 1, 11, 1},
+  {4, UPB_SIZE(20, 40), 0, 0, 11, 3},
+  {5, UPB_SIZE(24, 48), 0, 0, 9, 3},
 };
 
 const upb_msglayout google_protobuf_EnumDescriptorProto_msginit = {
@@ -217,15 +222,15 @@
 };
 
 static const upb_msglayout_field google_protobuf_EnumValueDescriptorProto__fields[3] = {
-  {1, UPB_SIZE(8, 16), 2, 0, 9, 1},
+  {1, UPB_SIZE(8, 8), 2, 0, 9, 1},
   {2, UPB_SIZE(4, 4), 1, 0, 5, 1},
-  {3, UPB_SIZE(16, 32), 3, 0, 11, 1},
+  {3, UPB_SIZE(16, 24), 3, 0, 11, 1},
 };
 
 const upb_msglayout google_protobuf_EnumValueDescriptorProto_msginit = {
   &google_protobuf_EnumValueDescriptorProto_submsgs[0],
   &google_protobuf_EnumValueDescriptorProto__fields[0],
-  UPB_SIZE(24, 48), 3, false,
+  UPB_SIZE(24, 32), 3, false,
 };
 
 static const upb_msglayout *const google_protobuf_ServiceDescriptorProto_submsgs[2] = {
@@ -234,9 +239,9 @@
 };
 
 static const upb_msglayout_field google_protobuf_ServiceDescriptorProto__fields[3] = {
-  {1, UPB_SIZE(8, 16), 1, 0, 9, 1},
-  {2, UPB_SIZE(20, 40), 0, 0, 11, 3},
-  {3, UPB_SIZE(16, 32), 2, 1, 11, 1},
+  {1, UPB_SIZE(4, 8), 1, 0, 9, 1},
+  {2, UPB_SIZE(16, 32), 0, 0, 11, 3},
+  {3, UPB_SIZE(12, 24), 2, 1, 11, 1},
 };
 
 const upb_msglayout google_protobuf_ServiceDescriptorProto_msginit = {
@@ -250,10 +255,10 @@
 };
 
 static const upb_msglayout_field google_protobuf_MethodDescriptorProto__fields[6] = {
-  {1, UPB_SIZE(8, 16), 3, 0, 9, 1},
-  {2, UPB_SIZE(16, 32), 4, 0, 9, 1},
-  {3, UPB_SIZE(24, 48), 5, 0, 9, 1},
-  {4, UPB_SIZE(32, 64), 6, 0, 11, 1},
+  {1, UPB_SIZE(4, 8), 3, 0, 9, 1},
+  {2, UPB_SIZE(12, 24), 4, 0, 9, 1},
+  {3, UPB_SIZE(20, 40), 5, 0, 9, 1},
+  {4, UPB_SIZE(28, 56), 6, 0, 11, 1},
   {5, UPB_SIZE(1, 1), 1, 0, 8, 1},
   {6, UPB_SIZE(2, 2), 2, 0, 8, 1},
 };
@@ -261,7 +266,7 @@
 const upb_msglayout google_protobuf_MethodDescriptorProto_msginit = {
   &google_protobuf_MethodDescriptorProto_submsgs[0],
   &google_protobuf_MethodDescriptorProto__fields[0],
-  UPB_SIZE(40, 80), 6, false,
+  UPB_SIZE(32, 64), 6, false,
 };
 
 static const upb_msglayout *const google_protobuf_FileOptions_submsgs[1] = {
@@ -269,11 +274,11 @@
 };
 
 static const upb_msglayout_field google_protobuf_FileOptions__fields[19] = {
-  {1, UPB_SIZE(32, 32), 11, 0, 9, 1},
-  {8, UPB_SIZE(40, 48), 12, 0, 9, 1},
+  {1, UPB_SIZE(28, 32), 11, 0, 9, 1},
+  {8, UPB_SIZE(36, 48), 12, 0, 9, 1},
   {9, UPB_SIZE(8, 8), 1, 0, 14, 1},
   {10, UPB_SIZE(16, 16), 2, 0, 8, 1},
-  {11, UPB_SIZE(48, 64), 13, 0, 9, 1},
+  {11, UPB_SIZE(44, 64), 13, 0, 9, 1},
   {16, UPB_SIZE(17, 17), 3, 0, 8, 1},
   {17, UPB_SIZE(18, 18), 4, 0, 8, 1},
   {18, UPB_SIZE(19, 19), 5, 0, 8, 1},
@@ -281,19 +286,19 @@
   {23, UPB_SIZE(21, 21), 7, 0, 8, 1},
   {27, UPB_SIZE(22, 22), 8, 0, 8, 1},
   {31, UPB_SIZE(23, 23), 9, 0, 8, 1},
-  {36, UPB_SIZE(56, 80), 14, 0, 9, 1},
-  {37, UPB_SIZE(64, 96), 15, 0, 9, 1},
-  {39, UPB_SIZE(72, 112), 16, 0, 9, 1},
-  {40, UPB_SIZE(80, 128), 17, 0, 9, 1},
-  {41, UPB_SIZE(88, 144), 18, 0, 9, 1},
+  {36, UPB_SIZE(52, 80), 14, 0, 9, 1},
+  {37, UPB_SIZE(60, 96), 15, 0, 9, 1},
+  {39, UPB_SIZE(68, 112), 16, 0, 9, 1},
+  {40, UPB_SIZE(76, 128), 17, 0, 9, 1},
+  {41, UPB_SIZE(84, 144), 18, 0, 9, 1},
   {42, UPB_SIZE(24, 24), 10, 0, 8, 1},
-  {999, UPB_SIZE(96, 160), 0, 0, 11, 3},
+  {999, UPB_SIZE(92, 160), 0, 0, 11, 3},
 };
 
 const upb_msglayout google_protobuf_FileOptions_msginit = {
   &google_protobuf_FileOptions_submsgs[0],
   &google_protobuf_FileOptions__fields[0],
-  UPB_SIZE(104, 176), 19, false,
+  UPB_SIZE(96, 176), 19, false,
 };
 
 static const upb_msglayout *const google_protobuf_MessageOptions_submsgs[1] = {
@@ -431,7 +436,7 @@
 };
 
 static const upb_msglayout_field google_protobuf_UninterpretedOption_NamePart__fields[2] = {
-  {1, UPB_SIZE(8, 16), 2, 0, 9, 2},
+  {1, UPB_SIZE(4, 8), 2, 0, 9, 2},
   {2, UPB_SIZE(1, 1), 1, 0, 8, 2},
 };
 
@@ -456,17 +461,17 @@
 };
 
 static const upb_msglayout_field google_protobuf_SourceCodeInfo_Location__fields[5] = {
-  {1, UPB_SIZE(24, 48), 0, 0, 5, 3},
-  {2, UPB_SIZE(28, 56), 0, 0, 5, 3},
-  {3, UPB_SIZE(8, 16), 1, 0, 9, 1},
-  {4, UPB_SIZE(16, 32), 2, 0, 9, 1},
-  {6, UPB_SIZE(32, 64), 0, 0, 9, 3},
+  {1, UPB_SIZE(20, 40), 0, 0, 5, 3},
+  {2, UPB_SIZE(24, 48), 0, 0, 5, 3},
+  {3, UPB_SIZE(4, 8), 1, 0, 9, 1},
+  {4, UPB_SIZE(12, 24), 2, 0, 9, 1},
+  {6, UPB_SIZE(28, 56), 0, 0, 9, 3},
 };
 
 const upb_msglayout google_protobuf_SourceCodeInfo_Location_msginit = {
   NULL,
   &google_protobuf_SourceCodeInfo_Location__fields[0],
-  UPB_SIZE(40, 80), 5, false,
+  UPB_SIZE(32, 64), 5, false,
 };
 
 static const upb_msglayout *const google_protobuf_GeneratedCodeInfo_submsgs[1] = {
@@ -484,8 +489,8 @@
 };
 
 static const upb_msglayout_field google_protobuf_GeneratedCodeInfo_Annotation__fields[4] = {
-  {1, UPB_SIZE(24, 32), 0, 0, 5, 3},
-  {2, UPB_SIZE(16, 16), 3, 0, 9, 1},
+  {1, UPB_SIZE(20, 32), 0, 0, 5, 3},
+  {2, UPB_SIZE(12, 16), 3, 0, 9, 1},
   {3, UPB_SIZE(4, 4), 1, 0, 5, 1},
   {4, UPB_SIZE(8, 8), 2, 0, 5, 1},
 };
@@ -493,11 +498,12 @@
 const upb_msglayout google_protobuf_GeneratedCodeInfo_Annotation_msginit = {
   NULL,
   &google_protobuf_GeneratedCodeInfo_Annotation__fields[0],
-  UPB_SIZE(32, 48), 4, false,
+  UPB_SIZE(24, 48), 4, false,
 };
 
 
 
+#include <string.h>
 
 /* Maps descriptor type -> upb field type.  */
 const uint8_t upb_desctype_to_fieldtype[] = {
@@ -608,14 +614,14 @@
 }
 
 static bool upb_decode_string(const char **ptr, const char *limit,
-                              upb_stringview *val) {
+                              upb_strview *val) {
   uint32_t len;
 
   CHK(upb_decode_varint32(ptr, limit, &len) &&
       len < INT32_MAX &&
       limit - *ptr >= (int32_t)len);
 
-  *val = upb_stringview_make(*ptr, len);
+  *val = upb_strview_make(*ptr, len);
   *ptr += len;
   return true;
 }
@@ -646,7 +652,7 @@
       return upb_decode_64bit(&d->ptr, frame->limit, &val);
     }
     case UPB_WIRE_TYPE_DELIMITED: {
-      upb_stringview val;
+      upb_strview val;
       return upb_decode_string(&d->ptr, frame->limit, &val);
     }
     case UPB_WIRE_TYPE_START_GROUP:
@@ -870,7 +876,7 @@
   return true;
 }
 
-static bool upb_decode_fixedpacked(upb_array *arr, upb_stringview data,
+static bool upb_decode_fixedpacked(upb_array *arr, upb_strview data,
                                    int elem_size) {
   int elements = data.size / elem_size;
   void *field_mem;
@@ -885,7 +891,7 @@
 static bool upb_decode_toarray(upb_decstate *d, upb_decframe *frame,
                                const char *field_start,
                                const upb_msglayout_field *field,
-                               upb_stringview val) {
+                               upb_strview val) {
   upb_array *arr = upb_getorcreatearr(frame, field);
 
 #define VARINT_CASE(ctype, decode) { \
@@ -966,7 +972,7 @@
 static bool upb_decode_delimitedfield(upb_decstate *d, upb_decframe *frame,
                                       const char *field_start,
                                       const upb_msglayout_field *field) {
-  upb_stringview val;
+  upb_strview val;
 
   CHK(upb_decode_string(&d->ptr, frame->limit, &val));
 
@@ -1080,7 +1086,7 @@
   return true;
 }
 
-bool upb_decode(upb_stringview buf, void *msg, const upb_msglayout *l) {
+bool upb_decode(upb_strview buf, void *msg, const upb_msglayout *l) {
   upb_decstate state;
   state.ptr = buf.data;
 
@@ -1091,6 +1097,7 @@
 
 
 #include <ctype.h>
+#include <errno.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -1099,8 +1106,8 @@
   char str[1];  /* Null-terminated string data follows. */
 } str_t;
 
-static str_t *newstr(const char *data, size_t len) {
-  str_t *ret = upb_gmalloc(sizeof(*ret) + len);
+static str_t *newstr(upb_alloc *alloc, const char *data, size_t len) {
+  str_t *ret = upb_malloc(alloc, sizeof(*ret) + len);
   if (!ret) return NULL;
   ret->len = len;
   memcpy(ret->str, data, len);
@@ -1108,7 +1115,113 @@
   return ret;
 }
 
-static void freestr(str_t *s) { upb_gfree(s); }
+struct upb_fielddef {
+  const upb_filedef *file;
+  const upb_msgdef *msgdef;
+  const char *full_name;
+  union {
+    int64_t sint;
+    uint64_t uint;
+    double dbl;
+    float flt;
+    bool boolean;
+    str_t *str;
+  } defaultval;
+  const upb_oneofdef *oneof;
+  union {
+    const upb_msgdef *msgdef;
+    const upb_enumdef *enumdef;
+    const google_protobuf_FieldDescriptorProto *unresolved;
+  } sub;
+  uint32_t number_;
+  uint32_t index_;
+  uint32_t selector_base;  /* Used to index into a upb::Handlers table. */
+  bool is_extension_;
+  bool lazy_;
+  bool packed_;
+  upb_descriptortype_t type_;
+  upb_label_t label_;
+};
+
+struct upb_msgdef {
+  const upb_filedef *file;
+  const char *full_name;
+  uint32_t selector_count;
+  uint32_t submsg_field_count;
+
+  /* Tables for looking up fields by number and name. */
+  upb_inttable itof;
+  upb_strtable ntof;
+
+  const upb_fielddef *fields;
+  const upb_oneofdef *oneofs;
+  int field_count;
+  int oneof_count;
+
+  /* Is this a map-entry message? */
+  bool map_entry;
+  upb_wellknowntype_t well_known_type;
+
+  /* TODO(haberman): proper extension ranges (there can be multiple). */
+};
+
+struct upb_enumdef {
+  const upb_filedef *file;
+  const char *full_name;
+  upb_strtable ntoi;
+  upb_inttable iton;
+  int32_t defaultval;
+};
+
+struct upb_oneofdef {
+  const upb_msgdef *parent;
+  const char *full_name;
+  uint32_t index;
+  upb_strtable ntof;
+  upb_inttable itof;
+};
+
+struct upb_filedef {
+  const char *name;
+  const char *package;
+  const char *phpprefix;
+  const char *phpnamespace;
+  upb_syntax_t syntax;
+
+  const upb_filedef **deps;
+  const upb_msgdef *msgs;
+  const upb_enumdef *enums;
+  const upb_fielddef *exts;
+
+  int dep_count;
+  int msg_count;
+  int enum_count;
+  int ext_count;
+};
+
+struct upb_symtab {
+  upb_arena *arena;
+  upb_strtable syms;  /* full_name -> packed def ptr */
+  upb_strtable files;  /* file_name -> upb_filedef* */
+};
+
+/* Inside a symtab we store tagged pointers to specific def types. */
+typedef enum {
+  UPB_DEFTYPE_MSG = 0,
+  UPB_DEFTYPE_ENUM = 1,
+  UPB_DEFTYPE_FIELD = 2,
+  UPB_DEFTYPE_ONEOF = 3
+} upb_deftype_t;
+
+static const void *unpack_def(upb_value v, upb_deftype_t type) {
+  uintptr_t num = (uintptr_t)upb_value_getconstptr(v);
+  return (num & 3) == type ? (const void*)(num & ~3) : NULL;
+}
+
+static upb_value pack_def(const void *ptr, upb_deftype_t type) {
+  uintptr_t num = (uintptr_t)ptr | type;
+  return upb_value_constptr((const void*)num);
+}
 
 /* isalpha() etc. from <ctype.h> are locale-dependent, which we don't want. */
 static bool upb_isbetween(char c, char low, char high) {
@@ -1123,7 +1236,9 @@
   return upb_isletter(c) || upb_isbetween(c, '0', '9');
 }
 
-static bool upb_isident(const char *str, size_t len, bool full, upb_status *s) {
+static bool upb_isident(upb_strview name, bool full, upb_status *s) {
+  const char *str = name.data;
+  size_t len = name.size;
   bool start = true;
   size_t i;
   for (i = 0; i < len; i++) {
@@ -1153,187 +1268,20 @@
   return !start;
 }
 
-static bool upb_isoneof(const upb_refcounted *def) {
-  return def->vtbl == &upb_oneofdef_vtbl;
-}
-
-static bool upb_isfield(const upb_refcounted *def) {
-  return def->vtbl == &upb_fielddef_vtbl;
-}
-
-static const upb_oneofdef *upb_trygetoneof(const upb_refcounted *def) {
-  return upb_isoneof(def) ? (const upb_oneofdef*)def : NULL;
-}
-
-static const upb_fielddef *upb_trygetfield(const upb_refcounted *def) {
-  return upb_isfield(def) ? (const upb_fielddef*)def : NULL;
-}
-
-
-/* upb_def ********************************************************************/
-
-upb_deftype_t upb_def_type(const upb_def *d) { return d->type; }
-
-const char *upb_def_fullname(const upb_def *d) { return d->fullname; }
-
-const char *upb_def_name(const upb_def *d) {
+static const char *shortdefname(const char *fullname) {
   const char *p;
 
-  if (d->fullname == NULL) {
+  if (fullname == NULL) {
     return NULL;
-  } else if ((p = strrchr(d->fullname, '.')) == NULL) {
+  } else if ((p = strrchr(fullname, '.')) == NULL) {
     /* No '.' in the name, return the full string. */
-    return d->fullname;
+    return fullname;
   } else {
     /* Return one past the last '.'. */
     return p + 1;
   }
 }
 
-bool upb_def_setfullname(upb_def *def, const char *fullname, upb_status *s) {
-  UPB_ASSERT(!upb_def_isfrozen(def));
-  if (!upb_isident(fullname, strlen(fullname), true, s)) {
-    return false;
-  }
-
-  fullname = upb_gstrdup(fullname);
-  if (!fullname) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-
-  upb_gfree((void*)def->fullname);
-  def->fullname = fullname;
-  return true;
-}
-
-const upb_filedef *upb_def_file(const upb_def *d) { return d->file; }
-
-static bool upb_def_init(upb_def *def, upb_deftype_t type,
-                         const struct upb_refcounted_vtbl *vtbl,
-                         const void *owner) {
-  if (!upb_refcounted_init(upb_def_upcast_mutable(def), vtbl, owner)) return false;
-  def->type = type;
-  def->fullname = NULL;
-  def->came_from_user = false;
-  def->file = NULL;
-  return true;
-}
-
-static void upb_def_uninit(upb_def *def) {
-  upb_gfree((void*)def->fullname);
-}
-
-static const char *msgdef_name(const upb_msgdef *m) {
-  const char *name = upb_def_fullname(upb_msgdef_upcast(m));
-  return name ? name : "(anonymous)";
-}
-
-static bool upb_validate_field(upb_fielddef *f, upb_status *s) {
-  if (upb_fielddef_name(f) == NULL || upb_fielddef_number(f) == 0) {
-    upb_status_seterrmsg(s, "fielddef must have name and number set");
-    return false;
-  }
-
-  if (!f->type_is_set_) {
-    upb_status_seterrmsg(s, "fielddef type was not initialized");
-    return false;
-  }
-
-  if (upb_fielddef_lazy(f) &&
-      upb_fielddef_descriptortype(f) != UPB_DESCRIPTOR_TYPE_MESSAGE) {
-    upb_status_seterrmsg(s,
-                         "only length-delimited submessage fields may be lazy");
-    return false;
-  }
-
-  if (upb_fielddef_hassubdef(f)) {
-    const upb_def *subdef;
-
-    if (f->subdef_is_symbolic) {
-      upb_status_seterrf(s, "field '%s.%s' has not been resolved",
-                         msgdef_name(f->msg.def), upb_fielddef_name(f));
-      return false;
-    }
-
-    subdef = upb_fielddef_subdef(f);
-    if (subdef == NULL) {
-      upb_status_seterrf(s, "field %s.%s is missing required subdef",
-                         msgdef_name(f->msg.def), upb_fielddef_name(f));
-      return false;
-    }
-
-    if (!upb_def_isfrozen(subdef) && !subdef->came_from_user) {
-      upb_status_seterrf(s,
-                         "subdef of field %s.%s is not frozen or being frozen",
-                         msgdef_name(f->msg.def), upb_fielddef_name(f));
-      return false;
-    }
-  }
-
-  if (upb_fielddef_type(f) == UPB_TYPE_ENUM) {
-    bool has_default_name = upb_fielddef_enumhasdefaultstr(f);
-    bool has_default_number = upb_fielddef_enumhasdefaultint32(f);
-
-    /* Previously verified by upb_validate_enumdef(). */
-    UPB_ASSERT(upb_enumdef_numvals(upb_fielddef_enumsubdef(f)) > 0);
-
-    /* We've already validated that we have an associated enumdef and that it
-     * has at least one member, so at least one of these should be true.
-     * Because if the user didn't set anything, we'll pick up the enum's
-     * default, but if the user *did* set something we should at least pick up
-     * the one they set (int32 or string). */
-    UPB_ASSERT(has_default_name || has_default_number);
-
-    if (!has_default_name) {
-      upb_status_seterrf(s,
-                         "enum default for field %s.%s (%d) is not in the enum",
-                         msgdef_name(f->msg.def), upb_fielddef_name(f),
-                         upb_fielddef_defaultint32(f));
-      return false;
-    }
-
-    if (!has_default_number) {
-      upb_status_seterrf(s,
-                         "enum default for field %s.%s (%s) is not in the enum",
-                         msgdef_name(f->msg.def), upb_fielddef_name(f),
-                         upb_fielddef_defaultstr(f, NULL));
-      return false;
-    }
-
-    /* Lift the effective numeric default into the field's default slot, in case
-     * we were only getting it "by reference" from the enumdef. */
-    upb_fielddef_setdefaultint32(f, upb_fielddef_defaultint32(f));
-  }
-
-  /* Ensure that MapEntry submessages only appear as repeated fields, not
-   * optional/required (singular) fields. */
-  if (upb_fielddef_type(f) == UPB_TYPE_MESSAGE &&
-      upb_fielddef_msgsubdef(f) != NULL) {
-    const upb_msgdef *subdef = upb_fielddef_msgsubdef(f);
-    if (upb_msgdef_mapentry(subdef) && !upb_fielddef_isseq(f)) {
-      upb_status_seterrf(s,
-                         "Field %s refers to mapentry message but is not "
-                         "a repeated field",
-                         upb_fielddef_name(f) ? upb_fielddef_name(f) :
-                         "(unnamed)");
-      return false;
-    }
-  }
-
-  return true;
-}
-
-static bool upb_validate_enumdef(const upb_enumdef *e, upb_status *s) {
-  if (upb_enumdef_numvals(e) == 0) {
-    upb_status_seterrf(s, "enum %s has no members (must have at least one)",
-                       upb_enumdef_fullname(e));
-    return false;
-  }
-
-  return true;
-}
-
 /* All submessage fields are lower than all other fields.
  * Secondly, fields are increasing in order. */
 uint32_t field_rank(const upb_fielddef *f) {
@@ -1369,7 +1317,7 @@
 
   fields = upb_gmalloc(n * sizeof(*fields));
   if (!fields) {
-    upb_upberr_setoom(s);
+    upb_status_setoom(s);
     return false;
   }
 
@@ -1378,11 +1326,7 @@
       !upb_msg_field_done(&j);
       upb_msg_field_next(&j), i++) {
     upb_fielddef *f = upb_msg_iter_field(&j);
-    UPB_ASSERT(f->msg.def == m);
-    if (!upb_validate_field(f, s)) {
-      upb_gfree(fields);
-      return false;
-    }
+    UPB_ASSERT(f->msgdef == m);
     if (upb_fielddef_issubmsg(f)) {
       m->submsg_field_count++;
     }
@@ -1404,7 +1348,7 @@
   {
     /* Verify that all selectors for the message are distinct. */
 #define TRY(type) \
-    if (upb_handlers_getselector(f, type, &sel)) upb_inttable_insert(&t, sel, v);
+    if (upb_handlers_getselector(f, type, &sel)) { upb_inttable_insert(&t, sel, v); }
 
     upb_inttable t;
     upb_value v;
@@ -1444,7 +1388,7 @@
   for(upb_msg_oneof_begin(&k, m), i = 0;
       !upb_msg_oneof_done(&k);
       upb_msg_oneof_next(&k), i++) {
-    upb_oneofdef *o = upb_msg_iter_oneof(&k);
+    upb_oneofdef *o = (upb_oneofdef*)upb_msg_iter_oneof(&k);
     o->index = i;
   }
 
@@ -1495,173 +1439,19 @@
   }
 }
 
-bool _upb_def_validate(upb_def *const*defs, size_t n, upb_status *s) {
-  size_t i;
-
-  /* First perform validation, in two passes so we can check that we have a
-   * transitive closure without needing to search. */
-  for (i = 0; i < n; i++) {
-    upb_def *def = defs[i];
-    if (upb_def_isfrozen(def)) {
-      /* Could relax this requirement if it's annoying. */
-      upb_status_seterrmsg(s, "def is already frozen");
-      goto err;
-    } else if (def->type == UPB_DEF_FIELD) {
-      upb_status_seterrmsg(s, "standalone fielddefs can not be frozen");
-      goto err;
-    } else {
-      /* Set now to detect transitive closure in the second pass. */
-      def->came_from_user = true;
-
-      if (def->type == UPB_DEF_ENUM &&
-          !upb_validate_enumdef(upb_dyncast_enumdef(def), s)) {
-        goto err;
-      }
-    }
-  }
-
-  /* Second pass of validation.  Also assign selector bases and indexes, and
-   * compact tables. */
-  for (i = 0; i < n; i++) {
-    upb_def *def = defs[i];
-    upb_msgdef *m = upb_dyncast_msgdef_mutable(def);
-    upb_enumdef *e = upb_dyncast_enumdef_mutable(def);
-    if (m) {
-      upb_inttable_compact(&m->itof);
-      if (!assign_msg_indices(m, s)) {
-        goto err;
-      }
-      assign_msg_wellknowntype(m);
-      /* m->well_known_type = UPB_WELLKNOWN_UNSPECIFIED; */
-    } else if (e) {
-      upb_inttable_compact(&e->iton);
-    }
-  }
-
-  return true;
-
-err:
-  for (i = 0; i < n; i++) {
-    upb_def *def = defs[i];
-    def->came_from_user = false;
-  }
-  UPB_ASSERT(!(s && upb_ok(s)));
-  return false;
-}
-
-bool upb_def_freeze(upb_def *const* defs, size_t n, upb_status *s) {
-  /* Def graph contains FieldDefs between each MessageDef, so double the
-   * limit. */
-  const size_t maxdepth = UPB_MAX_MESSAGE_DEPTH * 2;
-
-  if (!_upb_def_validate(defs, n, s)) {
-    return false;
-  }
-
-
-  /* Validation all passed; freeze the objects. */
-  return upb_refcounted_freeze((upb_refcounted *const*)defs, n, s, maxdepth);
-}
-
 
 /* upb_enumdef ****************************************************************/
 
-static void visitenum(const upb_refcounted *r, upb_refcounted_visit *visit,
-                      void *closure) {
-  const upb_enumdef *e = (const upb_enumdef*)r;
-  const upb_def *def = upb_enumdef_upcast(e);
-  if (upb_def_file(def)) {
-    visit(r, upb_filedef_upcast(upb_def_file(def)), closure);
-  }
-}
-
-static void freeenum(upb_refcounted *r) {
-  upb_enumdef *e = (upb_enumdef*)r;
-  upb_inttable_iter i;
-  upb_inttable_begin(&i, &e->iton);
-  for( ; !upb_inttable_done(&i); upb_inttable_next(&i)) {
-    /* To clean up the upb_gstrdup() from upb_enumdef_addval(). */
-    upb_gfree(upb_value_getcstr(upb_inttable_iter_value(&i)));
-  }
-  upb_strtable_uninit(&e->ntoi);
-  upb_inttable_uninit(&e->iton);
-  upb_def_uninit(upb_enumdef_upcast_mutable(e));
-  upb_gfree(e);
-}
-
-const struct upb_refcounted_vtbl upb_enumdef_vtbl = {&visitenum, &freeenum};
-
-upb_enumdef *upb_enumdef_new(const void *owner) {
-  upb_enumdef *e = upb_gmalloc(sizeof(*e));
-  if (!e) return NULL;
-
-  if (!upb_def_init(upb_enumdef_upcast_mutable(e), UPB_DEF_ENUM,
-                    &upb_enumdef_vtbl, owner)) {
-    goto err2;
-  }
-
-  if (!upb_strtable_init(&e->ntoi, UPB_CTYPE_INT32)) goto err2;
-  if (!upb_inttable_init(&e->iton, UPB_CTYPE_CSTR)) goto err1;
-  return e;
-
-err1:
-  upb_strtable_uninit(&e->ntoi);
-err2:
-  upb_gfree(e);
-  return NULL;
-}
-
-bool upb_enumdef_freeze(upb_enumdef *e, upb_status *status) {
-  upb_def *d = upb_enumdef_upcast_mutable(e);
-  return upb_def_freeze(&d, 1, status);
-}
-
 const char *upb_enumdef_fullname(const upb_enumdef *e) {
-  return upb_def_fullname(upb_enumdef_upcast(e));
+  return e->full_name;
 }
 
 const char *upb_enumdef_name(const upb_enumdef *e) {
-  return upb_def_name(upb_enumdef_upcast(e));
+  return shortdefname(e->full_name);
 }
 
-bool upb_enumdef_setfullname(upb_enumdef *e, const char *fullname,
-                             upb_status *s) {
-  return upb_def_setfullname(upb_enumdef_upcast_mutable(e), fullname, s);
-}
-
-bool upb_enumdef_addval(upb_enumdef *e, const char *name, int32_t num,
-                        upb_status *status) {
-  char *name2;
-
-  if (!upb_isident(name, strlen(name), false, status)) {
-    return false;
-  }
-
-  if (upb_enumdef_ntoiz(e, name, NULL)) {
-    upb_status_seterrf(status, "name '%s' is already defined", name);
-    return false;
-  }
-
-  if (!upb_strtable_insert(&e->ntoi, name, upb_value_int32(num))) {
-    upb_status_seterrmsg(status, "out of memory");
-    return false;
-  }
-
-  if (!upb_inttable_lookup(&e->iton, num, NULL)) {
-    name2 = upb_gstrdup(name);
-    if (!name2 || !upb_inttable_insert(&e->iton, num, upb_value_cstr(name2))) {
-      upb_status_seterrmsg(status, "out of memory");
-      upb_strtable_remove(&e->ntoi, name, NULL);
-      return false;
-    }
-  }
-
-  if (upb_enumdef_numvals(e) == 1) {
-    bool ok = upb_enumdef_setdefault(e, num, NULL);
-    UPB_ASSERT(ok);
-  }
-
-  return true;
+const upb_filedef *upb_enumdef_file(const upb_enumdef *e) {
+  return e->file;
 }
 
 int32_t upb_enumdef_default(const upb_enumdef *e) {
@@ -1669,16 +1459,6 @@
   return e->defaultval;
 }
 
-bool upb_enumdef_setdefault(upb_enumdef *e, int32_t val, upb_status *s) {
-  UPB_ASSERT(!upb_enumdef_isfrozen(e));
-  if (!upb_enumdef_iton(e, val)) {
-    upb_status_seterrf(s, "number '%d' is not in the enum.", val);
-    return false;
-  }
-  e->defaultval = val;
-  return true;
-}
-
 int upb_enumdef_numvals(const upb_enumdef *e) {
   return upb_strtable_count(&e->ntoi);
 }
@@ -1718,139 +1498,46 @@
 
 /* upb_fielddef ***************************************************************/
 
-static void upb_fielddef_init_default(upb_fielddef *f);
-
-static void upb_fielddef_uninit_default(upb_fielddef *f) {
-  if (f->type_is_set_ && f->default_is_string && f->defaultval.bytes)
-    freestr(f->defaultval.bytes);
-}
-
-const char *upb_fielddef_fullname(const upb_fielddef *e) {
-  return upb_def_fullname(upb_fielddef_upcast(e));
-}
-
-static void visitfield(const upb_refcounted *r, upb_refcounted_visit *visit,
-                       void *closure) {
-  const upb_fielddef *f = (const upb_fielddef*)r;
-  const upb_def *def = upb_fielddef_upcast(f);
-  if (upb_fielddef_containingtype(f)) {
-    visit(r, upb_msgdef_upcast2(upb_fielddef_containingtype(f)), closure);
-  }
-  if (upb_fielddef_containingoneof(f)) {
-    visit(r, upb_oneofdef_upcast(upb_fielddef_containingoneof(f)), closure);
-  }
-  if (upb_fielddef_subdef(f)) {
-    visit(r, upb_def_upcast(upb_fielddef_subdef(f)), closure);
-  }
-  if (upb_def_file(def)) {
-    visit(r, upb_filedef_upcast(upb_def_file(def)), closure);
-  }
-}
-
-static void freefield(upb_refcounted *r) {
-  upb_fielddef *f = (upb_fielddef*)r;
-  upb_fielddef_uninit_default(f);
-  if (f->subdef_is_symbolic)
-    upb_gfree(f->sub.name);
-  upb_def_uninit(upb_fielddef_upcast_mutable(f));
-  upb_gfree(f);
-}
-
-static const char *enumdefaultstr(const upb_fielddef *f) {
-  const upb_enumdef *e;
-  UPB_ASSERT(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
-  e = upb_fielddef_enumsubdef(f);
-  if (f->default_is_string && f->defaultval.bytes) {
-    /* Default was explicitly set as a string. */
-    str_t *s = f->defaultval.bytes;
-    return s->str;
-  } else if (e) {
-    if (!f->default_is_string) {
-      /* Default was explicitly set as an integer; look it up in enumdef. */
-      const char *name = upb_enumdef_iton(e, f->defaultval.sint);
-      if (name) {
-        return name;
-      }
-    } else {
-      /* Default is completely unset; pull enumdef default. */
-      if (upb_enumdef_numvals(e) > 0) {
-        const char *name = upb_enumdef_iton(e, upb_enumdef_default(e));
-        UPB_ASSERT(name);
-        return name;
-      }
-    }
-  }
-  return NULL;
-}
-
-static bool enumdefaultint32(const upb_fielddef *f, int32_t *val) {
-  const upb_enumdef *e;
-  UPB_ASSERT(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
-  e = upb_fielddef_enumsubdef(f);
-  if (!f->default_is_string) {
-    /* Default was explicitly set as an integer. */
-    *val = f->defaultval.sint;
-    return true;
-  } else if (e) {
-    if (f->defaultval.bytes) {
-      /* Default was explicitly set as a str; try to lookup corresponding int. */
-      str_t *s = f->defaultval.bytes;
-      if (upb_enumdef_ntoiz(e, s->str, val)) {
-        return true;
-      }
-    } else {
-      /* Default is unset; try to pull in enumdef default. */
-      if (upb_enumdef_numvals(e) > 0) {
-        *val = upb_enumdef_default(e);
-        return true;
-      }
-    }
-  }
-  return false;
-}
-
-const struct upb_refcounted_vtbl upb_fielddef_vtbl = {visitfield, freefield};
-
-upb_fielddef *upb_fielddef_new(const void *o) {
-  upb_fielddef *f = upb_gmalloc(sizeof(*f));
-  if (!f) return NULL;
-  if (!upb_def_init(upb_fielddef_upcast_mutable(f), UPB_DEF_FIELD,
-                    &upb_fielddef_vtbl, o)) {
-    upb_gfree(f);
-    return NULL;
-  }
-  f->msg.def = NULL;
-  f->sub.def = NULL;
-  f->oneof = NULL;
-  f->subdef_is_symbolic = false;
-  f->msg_is_symbolic = false;
-  f->label_ = UPB_LABEL_OPTIONAL;
-  f->type_ = UPB_TYPE_INT32;
-  f->number_ = 0;
-  f->type_is_set_ = false;
-  f->tagdelim = false;
-  f->is_extension_ = false;
-  f->lazy_ = false;
-  f->packed_ = true;
-
-  /* For the moment we default this to UPB_INTFMT_VARIABLE, since it will work
-   * with all integer types and is in some since more "default" since the most
-   * normal-looking proto2 types int32/int64/uint32/uint64 use variable.
-   *
-   * Other options to consider:
-   * - there is no default; users must set this manually (like type).
-   * - default signed integers to UPB_INTFMT_ZIGZAG, since it's more likely to
-   *   be an optimal default for signed integers. */
-  f->intfmt = UPB_INTFMT_VARIABLE;
-  return f;
-}
-
-bool upb_fielddef_typeisset(const upb_fielddef *f) {
-  return f->type_is_set_;
+const char *upb_fielddef_fullname(const upb_fielddef *f) {
+  return f->full_name;
 }
 
 upb_fieldtype_t upb_fielddef_type(const upb_fielddef *f) {
-  UPB_ASSERT(f->type_is_set_);
+  switch (f->type_) {
+    case UPB_DESCRIPTOR_TYPE_DOUBLE:
+      return UPB_TYPE_DOUBLE;
+    case UPB_DESCRIPTOR_TYPE_FLOAT:
+      return UPB_TYPE_FLOAT;
+    case UPB_DESCRIPTOR_TYPE_INT64:
+    case UPB_DESCRIPTOR_TYPE_SINT64:
+    case UPB_DESCRIPTOR_TYPE_SFIXED64:
+      return UPB_TYPE_INT64;
+    case UPB_DESCRIPTOR_TYPE_INT32:
+    case UPB_DESCRIPTOR_TYPE_SFIXED32:
+    case UPB_DESCRIPTOR_TYPE_SINT32:
+      return UPB_TYPE_INT32;
+    case UPB_DESCRIPTOR_TYPE_UINT64:
+    case UPB_DESCRIPTOR_TYPE_FIXED64:
+      return UPB_TYPE_UINT64;
+    case UPB_DESCRIPTOR_TYPE_UINT32:
+    case UPB_DESCRIPTOR_TYPE_FIXED32:
+      return UPB_TYPE_UINT32;
+    case UPB_DESCRIPTOR_TYPE_ENUM:
+      return UPB_TYPE_ENUM;
+    case UPB_DESCRIPTOR_TYPE_BOOL:
+      return UPB_TYPE_BOOL;
+    case UPB_DESCRIPTOR_TYPE_STRING:
+      return UPB_TYPE_STRING;
+    case UPB_DESCRIPTOR_TYPE_BYTES:
+      return UPB_TYPE_BYTES;
+    case UPB_DESCRIPTOR_TYPE_GROUP:
+    case UPB_DESCRIPTOR_TYPE_MESSAGE:
+      return UPB_TYPE_MESSAGE;
+  }
+  UPB_UNREACHABLE();
+}
+
+upb_descriptortype_t upb_fielddef_descriptortype(const upb_fielddef *f) {
   return f->type_;
 }
 
@@ -1862,14 +1549,6 @@
   return f->label_;
 }
 
-upb_intfmt_t upb_fielddef_intfmt(const upb_fielddef *f) {
-  return f->intfmt;
-}
-
-bool upb_fielddef_istagdelim(const upb_fielddef *f) {
-  return f->tagdelim;
-}
-
 uint32_t upb_fielddef_number(const upb_fielddef *f) {
   return f->number_;
 }
@@ -1887,7 +1566,11 @@
 }
 
 const char *upb_fielddef_name(const upb_fielddef *f) {
-  return upb_def_fullname(upb_fielddef_upcast(f));
+  return shortdefname(f->full_name);
+}
+
+uint32_t upb_fielddef_selectorbase(const upb_fielddef *f) {
+  return f->selector_base;
 }
 
 size_t upb_fielddef_getjsonname(const upb_fielddef *f, char *buf, size_t len) {
@@ -1930,60 +1613,16 @@
 }
 
 const upb_msgdef *upb_fielddef_containingtype(const upb_fielddef *f) {
-  return f->msg_is_symbolic ? NULL : f->msg.def;
+  return f->msgdef;
 }
 
 const upb_oneofdef *upb_fielddef_containingoneof(const upb_fielddef *f) {
   return f->oneof;
 }
 
-upb_msgdef *upb_fielddef_containingtype_mutable(upb_fielddef *f) {
-  return (upb_msgdef*)upb_fielddef_containingtype(f);
-}
-
-const char *upb_fielddef_containingtypename(upb_fielddef *f) {
-  return f->msg_is_symbolic ? f->msg.name : NULL;
-}
-
-static void release_containingtype(upb_fielddef *f) {
-  if (f->msg_is_symbolic) upb_gfree(f->msg.name);
-}
-
-bool upb_fielddef_setcontainingtypename(upb_fielddef *f, const char *name,
-                                        upb_status *s) {
-  char *name_copy;
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  if (upb_fielddef_containingtype(f)) {
-    upb_status_seterrmsg(s, "field has already been added to a message.");
-    return false;
-  }
-  /* TODO: validate name (upb_isident() doesn't quite work atm because this name
-   * may have a leading "."). */
-
-  name_copy = upb_gstrdup(name);
-  if (!name_copy) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-
-  release_containingtype(f);
-  f->msg.name = name_copy;
-  f->msg_is_symbolic = true;
-  return true;
-}
-
-bool upb_fielddef_setname(upb_fielddef *f, const char *name, upb_status *s) {
-  if (upb_fielddef_containingtype(f) || upb_fielddef_containingoneof(f)) {
-    upb_status_seterrmsg(s, "Already added to message or oneof");
-    return false;
-  }
-  return upb_def_setfullname(upb_fielddef_upcast_mutable(f), name, s);
-}
-
-static void chkdefaulttype(const upb_fielddef *f, upb_fieldtype_t type) {
+static void chkdefaulttype(const upb_fielddef *f, int ctype) {
   UPB_UNUSED(f);
-  UPB_UNUSED(type);
-  UPB_ASSERT(f->type_is_set_ && upb_fielddef_type(f) == type);
+  UPB_UNUSED(ctype);
 }
 
 int64_t upb_fielddef_defaultint64(const upb_fielddef *f) {
@@ -1992,15 +1631,8 @@
 }
 
 int32_t upb_fielddef_defaultint32(const upb_fielddef *f) {
-  if (f->type_is_set_ && upb_fielddef_type(f) == UPB_TYPE_ENUM) {
-    int32_t val;
-    bool ok = enumdefaultint32(f, &val);
-    UPB_ASSERT(ok);
-    return val;
-  } else {
-    chkdefaulttype(f, UPB_TYPE_INT32);
-    return f->defaultval.sint;
-  }
+  chkdefaulttype(f, UPB_TYPE_INT32);
+  return f->defaultval.sint;
 }
 
 uint64_t upb_fielddef_defaultuint64(const upb_fielddef *f) {
@@ -2015,7 +1647,7 @@
 
 bool upb_fielddef_defaultbool(const upb_fielddef *f) {
   chkdefaulttype(f, UPB_TYPE_BOOL);
-  return f->defaultval.uint;
+  return f->defaultval.boolean;
 }
 
 float upb_fielddef_defaultfloat(const upb_fielddef *f) {
@@ -2029,394 +1661,27 @@
 }
 
 const char *upb_fielddef_defaultstr(const upb_fielddef *f, size_t *len) {
-  UPB_ASSERT(f->type_is_set_);
+  str_t *str = f->defaultval.str;
   UPB_ASSERT(upb_fielddef_type(f) == UPB_TYPE_STRING ||
          upb_fielddef_type(f) == UPB_TYPE_BYTES ||
          upb_fielddef_type(f) == UPB_TYPE_ENUM);
-
-  if (upb_fielddef_type(f) == UPB_TYPE_ENUM) {
-    const char *ret = enumdefaultstr(f);
-    UPB_ASSERT(ret);
-    /* Enum defaults can't have embedded NULLs. */
-    if (len) *len = strlen(ret);
-    return ret;
-  }
-
-  if (f->default_is_string) {
-    str_t *str = f->defaultval.bytes;
+  if (str) {
     if (len) *len = str->len;
     return str->str;
-  }
-
-  return NULL;
-}
-
-static void upb_fielddef_init_default(upb_fielddef *f) {
-  f->default_is_string = false;
-  switch (upb_fielddef_type(f)) {
-    case UPB_TYPE_DOUBLE: f->defaultval.dbl = 0; break;
-    case UPB_TYPE_FLOAT: f->defaultval.flt = 0; break;
-    case UPB_TYPE_INT32:
-    case UPB_TYPE_INT64: f->defaultval.sint = 0; break;
-    case UPB_TYPE_UINT64:
-    case UPB_TYPE_UINT32:
-    case UPB_TYPE_BOOL: f->defaultval.uint = 0; break;
-    case UPB_TYPE_STRING:
-    case UPB_TYPE_BYTES:
-      f->defaultval.bytes = newstr("", 0);
-      f->default_is_string = true;
-      break;
-    case UPB_TYPE_MESSAGE: break;
-    case UPB_TYPE_ENUM:
-      /* This is our special sentinel that indicates "not set" for an enum. */
-      f->default_is_string = true;
-      f->defaultval.bytes = NULL;
-      break;
-  }
-}
-
-const upb_def *upb_fielddef_subdef(const upb_fielddef *f) {
-  return f->subdef_is_symbolic ? NULL : f->sub.def;
-}
-
-const upb_msgdef *upb_fielddef_msgsubdef(const upb_fielddef *f) {
-  const upb_def *def = upb_fielddef_subdef(f);
-  return def ? upb_dyncast_msgdef(def) : NULL;
-}
-
-const upb_enumdef *upb_fielddef_enumsubdef(const upb_fielddef *f) {
-  const upb_def *def = upb_fielddef_subdef(f);
-  return def ? upb_dyncast_enumdef(def) : NULL;
-}
-
-upb_def *upb_fielddef_subdef_mutable(upb_fielddef *f) {
-  return (upb_def*)upb_fielddef_subdef(f);
-}
-
-const char *upb_fielddef_subdefname(const upb_fielddef *f) {
-  if (f->subdef_is_symbolic) {
-    return f->sub.name;
-  } else if (f->sub.def) {
-    return upb_def_fullname(f->sub.def);
   } else {
+    if (len) *len = 0;
     return NULL;
   }
 }
 
-bool upb_fielddef_setnumber(upb_fielddef *f, uint32_t number, upb_status *s) {
-  if (upb_fielddef_containingtype(f)) {
-    upb_status_seterrmsg(
-        s, "cannot change field number after adding to a message");
-    return false;
-  }
-  if (number == 0 || number > UPB_MAX_FIELDNUMBER) {
-    upb_status_seterrf(s, "invalid field number (%u)", number);
-    return false;
-  }
-  f->number_ = number;
-  return true;
+const upb_msgdef *upb_fielddef_msgsubdef(const upb_fielddef *f) {
+  UPB_ASSERT(upb_fielddef_type(f) == UPB_TYPE_MESSAGE);
+  return f->sub.msgdef;
 }
 
-void upb_fielddef_settype(upb_fielddef *f, upb_fieldtype_t type) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  UPB_ASSERT(upb_fielddef_checktype(type));
-  upb_fielddef_uninit_default(f);
-  f->type_ = type;
-  f->type_is_set_ = true;
-  upb_fielddef_init_default(f);
-}
-
-void upb_fielddef_setdescriptortype(upb_fielddef *f, int type) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  switch (type) {
-    case UPB_DESCRIPTOR_TYPE_DOUBLE:
-      upb_fielddef_settype(f, UPB_TYPE_DOUBLE);
-      break;
-    case UPB_DESCRIPTOR_TYPE_FLOAT:
-      upb_fielddef_settype(f, UPB_TYPE_FLOAT);
-      break;
-    case UPB_DESCRIPTOR_TYPE_INT64:
-    case UPB_DESCRIPTOR_TYPE_SFIXED64:
-    case UPB_DESCRIPTOR_TYPE_SINT64:
-      upb_fielddef_settype(f, UPB_TYPE_INT64);
-      break;
-    case UPB_DESCRIPTOR_TYPE_UINT64:
-    case UPB_DESCRIPTOR_TYPE_FIXED64:
-      upb_fielddef_settype(f, UPB_TYPE_UINT64);
-      break;
-    case UPB_DESCRIPTOR_TYPE_INT32:
-    case UPB_DESCRIPTOR_TYPE_SFIXED32:
-    case UPB_DESCRIPTOR_TYPE_SINT32:
-      upb_fielddef_settype(f, UPB_TYPE_INT32);
-      break;
-    case UPB_DESCRIPTOR_TYPE_UINT32:
-    case UPB_DESCRIPTOR_TYPE_FIXED32:
-      upb_fielddef_settype(f, UPB_TYPE_UINT32);
-      break;
-    case UPB_DESCRIPTOR_TYPE_BOOL:
-      upb_fielddef_settype(f, UPB_TYPE_BOOL);
-      break;
-    case UPB_DESCRIPTOR_TYPE_STRING:
-      upb_fielddef_settype(f, UPB_TYPE_STRING);
-      break;
-    case UPB_DESCRIPTOR_TYPE_BYTES:
-      upb_fielddef_settype(f, UPB_TYPE_BYTES);
-      break;
-    case UPB_DESCRIPTOR_TYPE_GROUP:
-    case UPB_DESCRIPTOR_TYPE_MESSAGE:
-      upb_fielddef_settype(f, UPB_TYPE_MESSAGE);
-      break;
-    case UPB_DESCRIPTOR_TYPE_ENUM:
-      upb_fielddef_settype(f, UPB_TYPE_ENUM);
-      break;
-    default: UPB_ASSERT(false);
-  }
-
-  if (type == UPB_DESCRIPTOR_TYPE_FIXED64 ||
-      type == UPB_DESCRIPTOR_TYPE_FIXED32 ||
-      type == UPB_DESCRIPTOR_TYPE_SFIXED64 ||
-      type == UPB_DESCRIPTOR_TYPE_SFIXED32) {
-    upb_fielddef_setintfmt(f, UPB_INTFMT_FIXED);
-  } else if (type == UPB_DESCRIPTOR_TYPE_SINT64 ||
-             type == UPB_DESCRIPTOR_TYPE_SINT32) {
-    upb_fielddef_setintfmt(f, UPB_INTFMT_ZIGZAG);
-  } else {
-    upb_fielddef_setintfmt(f, UPB_INTFMT_VARIABLE);
-  }
-
-  upb_fielddef_settagdelim(f, type == UPB_DESCRIPTOR_TYPE_GROUP);
-}
-
-upb_descriptortype_t upb_fielddef_descriptortype(const upb_fielddef *f) {
-  switch (upb_fielddef_type(f)) {
-    case UPB_TYPE_FLOAT:  return UPB_DESCRIPTOR_TYPE_FLOAT;
-    case UPB_TYPE_DOUBLE: return UPB_DESCRIPTOR_TYPE_DOUBLE;
-    case UPB_TYPE_BOOL:   return UPB_DESCRIPTOR_TYPE_BOOL;
-    case UPB_TYPE_STRING: return UPB_DESCRIPTOR_TYPE_STRING;
-    case UPB_TYPE_BYTES:  return UPB_DESCRIPTOR_TYPE_BYTES;
-    case UPB_TYPE_ENUM:   return UPB_DESCRIPTOR_TYPE_ENUM;
-    case UPB_TYPE_INT32:
-      switch (upb_fielddef_intfmt(f)) {
-        case UPB_INTFMT_VARIABLE: return UPB_DESCRIPTOR_TYPE_INT32;
-        case UPB_INTFMT_FIXED:    return UPB_DESCRIPTOR_TYPE_SFIXED32;
-        case UPB_INTFMT_ZIGZAG:   return UPB_DESCRIPTOR_TYPE_SINT32;
-      }
-    case UPB_TYPE_INT64:
-      switch (upb_fielddef_intfmt(f)) {
-        case UPB_INTFMT_VARIABLE: return UPB_DESCRIPTOR_TYPE_INT64;
-        case UPB_INTFMT_FIXED:    return UPB_DESCRIPTOR_TYPE_SFIXED64;
-        case UPB_INTFMT_ZIGZAG:   return UPB_DESCRIPTOR_TYPE_SINT64;
-      }
-    case UPB_TYPE_UINT32:
-      switch (upb_fielddef_intfmt(f)) {
-        case UPB_INTFMT_VARIABLE: return UPB_DESCRIPTOR_TYPE_UINT32;
-        case UPB_INTFMT_FIXED:    return UPB_DESCRIPTOR_TYPE_FIXED32;
-        case UPB_INTFMT_ZIGZAG:   return -1;
-      }
-    case UPB_TYPE_UINT64:
-      switch (upb_fielddef_intfmt(f)) {
-        case UPB_INTFMT_VARIABLE: return UPB_DESCRIPTOR_TYPE_UINT64;
-        case UPB_INTFMT_FIXED:    return UPB_DESCRIPTOR_TYPE_FIXED64;
-        case UPB_INTFMT_ZIGZAG:   return -1;
-      }
-    case UPB_TYPE_MESSAGE:
-      return upb_fielddef_istagdelim(f) ?
-          UPB_DESCRIPTOR_TYPE_GROUP : UPB_DESCRIPTOR_TYPE_MESSAGE;
-  }
-  return 0;
-}
-
-void upb_fielddef_setisextension(upb_fielddef *f, bool is_extension) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  f->is_extension_ = is_extension;
-}
-
-void upb_fielddef_setlazy(upb_fielddef *f, bool lazy) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  f->lazy_ = lazy;
-}
-
-void upb_fielddef_setpacked(upb_fielddef *f, bool packed) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  f->packed_ = packed;
-}
-
-void upb_fielddef_setlabel(upb_fielddef *f, upb_label_t label) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  UPB_ASSERT(upb_fielddef_checklabel(label));
-  f->label_ = label;
-}
-
-void upb_fielddef_setintfmt(upb_fielddef *f, upb_intfmt_t fmt) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  UPB_ASSERT(upb_fielddef_checkintfmt(fmt));
-  f->intfmt = fmt;
-}
-
-void upb_fielddef_settagdelim(upb_fielddef *f, bool tag_delim) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  f->tagdelim = tag_delim;
-  f->tagdelim = tag_delim;
-}
-
-static bool checksetdefault(upb_fielddef *f, upb_fieldtype_t type) {
-  if (!f->type_is_set_ || upb_fielddef_isfrozen(f) ||
-      upb_fielddef_type(f) != type) {
-    UPB_ASSERT(false);
-    return false;
-  }
-  if (f->default_is_string) {
-    str_t *s = f->defaultval.bytes;
-    UPB_ASSERT(s || type == UPB_TYPE_ENUM);
-    if (s) freestr(s);
-  }
-  f->default_is_string = false;
-  return true;
-}
-
-void upb_fielddef_setdefaultint64(upb_fielddef *f, int64_t value) {
-  if (checksetdefault(f, UPB_TYPE_INT64))
-    f->defaultval.sint = value;
-}
-
-void upb_fielddef_setdefaultint32(upb_fielddef *f, int32_t value) {
-  if ((upb_fielddef_type(f) == UPB_TYPE_ENUM &&
-       checksetdefault(f, UPB_TYPE_ENUM)) ||
-      checksetdefault(f, UPB_TYPE_INT32)) {
-    f->defaultval.sint = value;
-  }
-}
-
-void upb_fielddef_setdefaultuint64(upb_fielddef *f, uint64_t value) {
-  if (checksetdefault(f, UPB_TYPE_UINT64))
-    f->defaultval.uint = value;
-}
-
-void upb_fielddef_setdefaultuint32(upb_fielddef *f, uint32_t value) {
-  if (checksetdefault(f, UPB_TYPE_UINT32))
-    f->defaultval.uint = value;
-}
-
-void upb_fielddef_setdefaultbool(upb_fielddef *f, bool value) {
-  if (checksetdefault(f, UPB_TYPE_BOOL))
-    f->defaultval.uint = value;
-}
-
-void upb_fielddef_setdefaultfloat(upb_fielddef *f, float value) {
-  if (checksetdefault(f, UPB_TYPE_FLOAT))
-    f->defaultval.flt = value;
-}
-
-void upb_fielddef_setdefaultdouble(upb_fielddef *f, double value) {
-  if (checksetdefault(f, UPB_TYPE_DOUBLE))
-    f->defaultval.dbl = value;
-}
-
-bool upb_fielddef_setdefaultstr(upb_fielddef *f, const void *str, size_t len,
-                                upb_status *s) {
-  str_t *str2;
-  UPB_ASSERT(upb_fielddef_isstring(f) || f->type_ == UPB_TYPE_ENUM);
-  if (f->type_ == UPB_TYPE_ENUM && !upb_isident(str, len, false, s))
-    return false;
-
-  if (f->default_is_string) {
-    str_t *s = f->defaultval.bytes;
-    UPB_ASSERT(s || f->type_ == UPB_TYPE_ENUM);
-    if (s) freestr(s);
-  } else {
-    UPB_ASSERT(f->type_ == UPB_TYPE_ENUM);
-  }
-
-  str2 = newstr(str, len);
-  f->defaultval.bytes = str2;
-  f->default_is_string = true;
-  return true;
-}
-
-void upb_fielddef_setdefaultcstr(upb_fielddef *f, const char *str,
-                                 upb_status *s) {
-  UPB_ASSERT(f->type_is_set_);
-  upb_fielddef_setdefaultstr(f, str, str ? strlen(str) : 0, s);
-}
-
-bool upb_fielddef_enumhasdefaultint32(const upb_fielddef *f) {
-  int32_t val;
-  UPB_ASSERT(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
-  return enumdefaultint32(f, &val);
-}
-
-bool upb_fielddef_enumhasdefaultstr(const upb_fielddef *f) {
-  UPB_ASSERT(f->type_is_set_ && f->type_ == UPB_TYPE_ENUM);
-  return enumdefaultstr(f) != NULL;
-}
-
-static bool upb_subdef_typecheck(upb_fielddef *f, const upb_def *subdef,
-                                 upb_status *s) {
-  if (f->type_ == UPB_TYPE_MESSAGE) {
-    if (upb_dyncast_msgdef(subdef)) return true;
-    upb_status_seterrmsg(s, "invalid subdef type for this submessage field");
-    return false;
-  } else if (f->type_ == UPB_TYPE_ENUM) {
-    if (upb_dyncast_enumdef(subdef)) return true;
-    upb_status_seterrmsg(s, "invalid subdef type for this enum field");
-    return false;
-  } else {
-    upb_status_seterrmsg(s, "only message and enum fields can have a subdef");
-    return false;
-  }
-}
-
-static void release_subdef(upb_fielddef *f) {
-  if (f->subdef_is_symbolic) {
-    upb_gfree(f->sub.name);
-  } else if (f->sub.def) {
-    upb_unref2(f->sub.def, f);
-  }
-}
-
-bool upb_fielddef_setsubdef(upb_fielddef *f, const upb_def *subdef,
-                            upb_status *s) {
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  UPB_ASSERT(upb_fielddef_hassubdef(f));
-  if (subdef && !upb_subdef_typecheck(f, subdef, s)) return false;
-  release_subdef(f);
-  f->sub.def = subdef;
-  f->subdef_is_symbolic = false;
-  if (f->sub.def) upb_ref2(f->sub.def, f);
-  return true;
-}
-
-bool upb_fielddef_setmsgsubdef(upb_fielddef *f, const upb_msgdef *subdef,
-                               upb_status *s) {
-  return upb_fielddef_setsubdef(f, upb_msgdef_upcast(subdef), s);
-}
-
-bool upb_fielddef_setenumsubdef(upb_fielddef *f, const upb_enumdef *subdef,
-                                upb_status *s) {
-  return upb_fielddef_setsubdef(f, upb_enumdef_upcast(subdef), s);
-}
-
-bool upb_fielddef_setsubdefname(upb_fielddef *f, const char *name,
-                                upb_status *s) {
-  char *name_copy;
-  UPB_ASSERT(!upb_fielddef_isfrozen(f));
-  if (!upb_fielddef_hassubdef(f)) {
-    upb_status_seterrmsg(s, "field type does not accept a subdef");
-    return false;
-  }
-
-  name_copy = upb_gstrdup(name);
-  if (!name_copy) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-
-  /* TODO: validate name (upb_isident() doesn't quite work atm because this name
-   * may have a leading "."). */
-  release_subdef(f);
-  f->sub.name = name_copy;
-  f->subdef_is_symbolic = true;
-  return true;
+const upb_enumdef *upb_fielddef_enumsubdef(const upb_fielddef *f) {
+  UPB_ASSERT(upb_fielddef_type(f) == UPB_TYPE_ENUM);
+  return f->sub.enumdef;
 }
 
 bool upb_fielddef_issubmsg(const upb_fielddef *f) {
@@ -2441,18 +1706,14 @@
          upb_msgdef_mapentry(upb_fielddef_msgsubdef(f));
 }
 
+bool upb_fielddef_hassubdef(const upb_fielddef *f) {
+  return upb_fielddef_issubmsg(f) || upb_fielddef_type(f) == UPB_TYPE_ENUM;
+}
+
 bool upb_fielddef_haspresence(const upb_fielddef *f) {
   if (upb_fielddef_isseq(f)) return false;
   if (upb_fielddef_issubmsg(f)) return true;
-
-  /* Primitive field: return true unless there is a message that specifies
-   * presence should not exist. */
-  if (f->msg_is_symbolic || !f->msg.def) return true;
-  return f->msg.def->syntax == UPB_SYNTAX_PROTO2;
-}
-
-bool upb_fielddef_hassubdef(const upb_fielddef *f) {
-  return upb_fielddef_issubmsg(f) || upb_fielddef_type(f) == UPB_TYPE_ENUM;
+  return f->file->syntax == UPB_SYNTAX_PROTO2;
 }
 
 static bool between(int32_t x, int32_t low, int32_t high) {
@@ -2469,205 +1730,34 @@
 
 /* upb_msgdef *****************************************************************/
 
-static void visitmsg(const upb_refcounted *r, upb_refcounted_visit *visit,
-                     void *closure) {
-  upb_msg_oneof_iter o;
-  const upb_msgdef *m = (const upb_msgdef*)r;
-  const upb_def *def = upb_msgdef_upcast(m);
-  upb_msg_field_iter i;
-  for(upb_msg_field_begin(&i, m);
-      !upb_msg_field_done(&i);
-      upb_msg_field_next(&i)) {
-    upb_fielddef *f = upb_msg_iter_field(&i);
-    visit(r, upb_fielddef_upcast2(f), closure);
-  }
-  for(upb_msg_oneof_begin(&o, m);
-      !upb_msg_oneof_done(&o);
-      upb_msg_oneof_next(&o)) {
-    upb_oneofdef *f = upb_msg_iter_oneof(&o);
-    visit(r, upb_oneofdef_upcast(f), closure);
-  }
-  if (upb_def_file(def)) {
-    visit(r, upb_filedef_upcast(upb_def_file(def)), closure);
-  }
-}
-
-static void freemsg(upb_refcounted *r) {
-  upb_msgdef *m = (upb_msgdef*)r;
-  upb_strtable_uninit(&m->ntof);
-  upb_inttable_uninit(&m->itof);
-  upb_def_uninit(upb_msgdef_upcast_mutable(m));
-  upb_gfree(m);
-}
-
-const struct upb_refcounted_vtbl upb_msgdef_vtbl = {visitmsg, freemsg};
-
-upb_msgdef *upb_msgdef_new(const void *owner) {
-  upb_msgdef *m = upb_gmalloc(sizeof(*m));
-  if (!m) return NULL;
-
-  if (!upb_def_init(upb_msgdef_upcast_mutable(m), UPB_DEF_MSG, &upb_msgdef_vtbl,
-                    owner)) {
-    goto err2;
-  }
-
-  if (!upb_inttable_init(&m->itof, UPB_CTYPE_PTR)) goto err2;
-  if (!upb_strtable_init(&m->ntof, UPB_CTYPE_PTR)) goto err1;
-  m->map_entry = false;
-  m->syntax = UPB_SYNTAX_PROTO2;
-  return m;
-
-err1:
-  upb_inttable_uninit(&m->itof);
-err2:
-  upb_gfree(m);
-  return NULL;
-}
-
-bool upb_msgdef_freeze(upb_msgdef *m, upb_status *status) {
-  upb_def *d = upb_msgdef_upcast_mutable(m);
-  return upb_def_freeze(&d, 1, status);
-}
-
 const char *upb_msgdef_fullname(const upb_msgdef *m) {
-  return upb_def_fullname(upb_msgdef_upcast(m));
+  return m->full_name;
+}
+
+const upb_filedef *upb_msgdef_file(const upb_msgdef *m) {
+  return m->file;
 }
 
 const char *upb_msgdef_name(const upb_msgdef *m) {
-  return upb_def_name(upb_msgdef_upcast(m));
-}
-
-bool upb_msgdef_setfullname(upb_msgdef *m, const char *fullname,
-                            upb_status *s) {
-  return upb_def_setfullname(upb_msgdef_upcast_mutable(m), fullname, s);
-}
-
-bool upb_msgdef_setsyntax(upb_msgdef *m, upb_syntax_t syntax) {
-  if (syntax != UPB_SYNTAX_PROTO2 && syntax != UPB_SYNTAX_PROTO3) {
-    return false;
-  }
-
-  m->syntax = syntax;
-  return true;
+  return shortdefname(m->full_name);
 }
 
 upb_syntax_t upb_msgdef_syntax(const upb_msgdef *m) {
-  return m->syntax;
+  return m->file->syntax;
 }
 
-/* Helper: check that the field |f| is safe to add to msgdef |m|. Set an error
- * on status |s| and return false if not. */
-static bool check_field_add(const upb_msgdef *m, const upb_fielddef *f,
-                            upb_status *s) {
-  if (upb_fielddef_containingtype(f) != NULL) {
-    upb_status_seterrmsg(s, "fielddef already belongs to a message");
-    return false;
-  } else if (upb_fielddef_name(f) == NULL || upb_fielddef_number(f) == 0) {
-    upb_status_seterrmsg(s, "field name or number were not set");
-    return false;
-  } else if (upb_msgdef_itof(m, upb_fielddef_number(f))) {
-    upb_status_seterrmsg(s, "duplicate field number");
-    return false;
-  } else if (upb_strtable_lookup(&m->ntof, upb_fielddef_name(f), NULL)) {
-    upb_status_seterrmsg(s, "name conflicts with existing field or oneof");
-    return false;
-  }
-  return true;
+size_t upb_msgdef_selectorcount(const upb_msgdef *m) {
+  return m->selector_count;
 }
 
-static void add_field(upb_msgdef *m, upb_fielddef *f, const void *ref_donor) {
-  release_containingtype(f);
-  f->msg.def = m;
-  f->msg_is_symbolic = false;
-  upb_inttable_insert(&m->itof, upb_fielddef_number(f), upb_value_ptr(f));
-  upb_strtable_insert(&m->ntof, upb_fielddef_name(f), upb_value_ptr(f));
-  upb_ref2(f, m);
-  upb_ref2(m, f);
-  if (ref_donor) upb_fielddef_unref(f, ref_donor);
-}
-
-bool upb_msgdef_addfield(upb_msgdef *m, upb_fielddef *f, const void *ref_donor,
-                         upb_status *s) {
-  /* TODO: extensions need to have a separate namespace, because proto2 allows a
-   * top-level extension (ie. one not in any package) to have the same name as a
-   * field from the message.
-   *
-   * This also implies that there needs to be a separate lookup-by-name method
-   * for extensions.  It seems desirable for iteration to return both extensions
-   * and non-extensions though.
-   *
-   * We also need to validate that the field number is in an extension range iff
-   * it is an extension.
-   *
-   * This method is idempotent. Check if |f| is already part of this msgdef and
-   * return immediately if so. */
-  if (upb_fielddef_containingtype(f) == m) {
-    if (ref_donor) upb_fielddef_unref(f, ref_donor);
-    return true;
-  }
-
-  /* Check constraints for all fields before performing any action. */
-  if (!check_field_add(m, f, s)) {
-    return false;
-  } else if (upb_fielddef_containingoneof(f) != NULL) {
-    /* Fields in a oneof can only be added by adding the oneof to the msgdef. */
-    upb_status_seterrmsg(s, "fielddef is part of a oneof");
-    return false;
-  }
-
-  /* Constraint checks ok, perform the action. */
-  add_field(m, f, ref_donor);
-  return true;
-}
-
-bool upb_msgdef_addoneof(upb_msgdef *m, upb_oneofdef *o, const void *ref_donor,
-                         upb_status *s) {
-  upb_oneof_iter it;
-
-  /* Check various conditions that would prevent this oneof from being added. */
-  if (upb_oneofdef_containingtype(o)) {
-    upb_status_seterrmsg(s, "oneofdef already belongs to a message");
-    return false;
-  } else if (upb_oneofdef_name(o) == NULL) {
-    upb_status_seterrmsg(s, "oneofdef name was not set");
-    return false;
-  } else if (upb_strtable_lookup(&m->ntof, upb_oneofdef_name(o), NULL)) {
-    upb_status_seterrmsg(s, "name conflicts with existing field or oneof");
-    return false;
-  }
-
-  /* Check that all of the oneof's fields do not conflict with names or numbers
-   * of fields already in the message. */
-  for (upb_oneof_begin(&it, o); !upb_oneof_done(&it); upb_oneof_next(&it)) {
-    const upb_fielddef *f = upb_oneof_iter_field(&it);
-    if (!check_field_add(m, f, s)) {
-      return false;
-    }
-  }
-
-  /* Everything checks out -- commit now. */
-
-  /* Add oneof itself first. */
-  o->parent = m;
-  upb_strtable_insert(&m->ntof, upb_oneofdef_name(o), upb_value_ptr(o));
-  upb_ref2(o, m);
-  upb_ref2(m, o);
-
-  /* Add each field of the oneof directly to the msgdef. */
-  for (upb_oneof_begin(&it, o); !upb_oneof_done(&it); upb_oneof_next(&it)) {
-    upb_fielddef *f = upb_oneof_iter_field(&it);
-    add_field(m, f, NULL);
-  }
-
-  if (ref_donor) upb_oneofdef_unref(o, ref_donor);
-
-  return true;
+uint32_t upb_msgdef_submsgfieldcount(const upb_msgdef *m) {
+  return m->submsg_field_count;
 }
 
 const upb_fielddef *upb_msgdef_itof(const upb_msgdef *m, uint32_t i) {
   upb_value val;
   return upb_inttable_lookup32(&m->itof, i, &val) ?
-      upb_value_getptr(val) : NULL;
+      upb_value_getconstptr(val) : NULL;
 }
 
 const upb_fielddef *upb_msgdef_ntof(const upb_msgdef *m, const char *name,
@@ -2678,7 +1768,7 @@
     return NULL;
   }
 
-  return upb_trygetfield(upb_value_getptr(val));
+  return unpack_def(val, UPB_DEFTYPE_FIELD);
 }
 
 const upb_oneofdef *upb_msgdef_ntoo(const upb_msgdef *m, const char *name,
@@ -2689,7 +1779,7 @@
     return NULL;
   }
 
-  return upb_trygetoneof(upb_value_getptr(val));
+  return unpack_def(val, UPB_DEFTYPE_ONEOF);
 }
 
 bool upb_msgdef_lookupname(const upb_msgdef *m, const char *name, size_t len,
@@ -2700,8 +1790,8 @@
     return false;
   }
 
-  *o = upb_trygetoneof(upb_value_getptr(val));
-  *f = upb_trygetfield(upb_value_getptr(val));
+  *o = unpack_def(val, UPB_DEFTYPE_ONEOF);
+  *f = unpack_def(val, UPB_DEFTYPE_FIELD);
   UPB_ASSERT((*o != NULL) ^ (*f != NULL));  /* Exactly one of the two should be set. */
   return true;
 }
@@ -2716,11 +1806,6 @@
   return upb_strtable_count(&m->ntof) - upb_inttable_count(&m->itof);
 }
 
-void upb_msgdef_setmapentry(upb_msgdef *m, bool map_entry) {
-  UPB_ASSERT(!upb_msgdef_isfrozen(m));
-  m->map_entry = map_entry;
-}
-
 bool upb_msgdef_mapentry(const upb_msgdef *m) {
   return m->map_entry;
 }
@@ -2746,18 +1831,23 @@
 }
 
 upb_fielddef *upb_msg_iter_field(const upb_msg_field_iter *iter) {
-  return (upb_fielddef*)upb_value_getptr(upb_inttable_iter_value(iter));
+  return (upb_fielddef *)upb_value_getconstptr(upb_inttable_iter_value(iter));
 }
 
 void upb_msg_field_iter_setdone(upb_msg_field_iter *iter) {
   upb_inttable_iter_setdone(iter);
 }
 
+bool upb_msg_field_iter_isequal(const upb_msg_field_iter * iter1,
+                                const upb_msg_field_iter * iter2) {
+  return upb_inttable_iter_isequal(iter1, iter2);
+}
+
 void upb_msg_oneof_begin(upb_msg_oneof_iter *iter, const upb_msgdef *m) {
   upb_strtable_begin(iter, &m->ntof);
   /* We need to skip past any initial fields. */
   while (!upb_strtable_done(iter) &&
-         !upb_isoneof(upb_value_getptr(upb_strtable_iter_value(iter)))) {
+         !unpack_def(upb_strtable_iter_value(iter), UPB_DEFTYPE_ONEOF)) {
     upb_strtable_next(iter);
   }
 }
@@ -2767,95 +1857,30 @@
   do {
     upb_strtable_next(iter);
   } while (!upb_strtable_done(iter) &&
-           !upb_isoneof(upb_value_getptr(upb_strtable_iter_value(iter))));
+           !unpack_def(upb_strtable_iter_value(iter), UPB_DEFTYPE_ONEOF));
 }
 
 bool upb_msg_oneof_done(const upb_msg_oneof_iter *iter) {
   return upb_strtable_done(iter);
 }
 
-upb_oneofdef *upb_msg_iter_oneof(const upb_msg_oneof_iter *iter) {
-  return (upb_oneofdef*)upb_value_getptr(upb_strtable_iter_value(iter));
+const upb_oneofdef *upb_msg_iter_oneof(const upb_msg_oneof_iter *iter) {
+  return unpack_def(upb_strtable_iter_value(iter), UPB_DEFTYPE_ONEOF);
 }
 
 void upb_msg_oneof_iter_setdone(upb_msg_oneof_iter *iter) {
   upb_strtable_iter_setdone(iter);
 }
 
+bool upb_msg_oneof_iter_isequal(const upb_msg_oneof_iter *iter1,
+                                const upb_msg_oneof_iter *iter2) {
+  return upb_strtable_iter_isequal(iter1, iter2);
+}
+
 /* upb_oneofdef ***************************************************************/
 
-static void visitoneof(const upb_refcounted *r, upb_refcounted_visit *visit,
-                       void *closure) {
-  const upb_oneofdef *o = (const upb_oneofdef*)r;
-  upb_oneof_iter i;
-  for (upb_oneof_begin(&i, o); !upb_oneof_done(&i); upb_oneof_next(&i)) {
-    const upb_fielddef *f = upb_oneof_iter_field(&i);
-    visit(r, upb_fielddef_upcast2(f), closure);
-  }
-  if (o->parent) {
-    visit(r, upb_msgdef_upcast2(o->parent), closure);
-  }
-}
-
-static void freeoneof(upb_refcounted *r) {
-  upb_oneofdef *o = (upb_oneofdef*)r;
-  upb_strtable_uninit(&o->ntof);
-  upb_inttable_uninit(&o->itof);
-  upb_gfree((void*)o->name);
-  upb_gfree(o);
-}
-
-const struct upb_refcounted_vtbl upb_oneofdef_vtbl = {visitoneof, freeoneof};
-
-upb_oneofdef *upb_oneofdef_new(const void *owner) {
-  upb_oneofdef *o = upb_gmalloc(sizeof(*o));
-
-  if (!o) {
-    return NULL;
-  }
-
-  o->parent = NULL;
-  o->name = NULL;
-
-  if (!upb_refcounted_init(upb_oneofdef_upcast_mutable(o), &upb_oneofdef_vtbl,
-                           owner)) {
-    goto err2;
-  }
-
-  if (!upb_inttable_init(&o->itof, UPB_CTYPE_PTR)) goto err2;
-  if (!upb_strtable_init(&o->ntof, UPB_CTYPE_PTR)) goto err1;
-
-  return o;
-
-err1:
-  upb_inttable_uninit(&o->itof);
-err2:
-  upb_gfree(o);
-  return NULL;
-}
-
-const char *upb_oneofdef_name(const upb_oneofdef *o) { return o->name; }
-
-bool upb_oneofdef_setname(upb_oneofdef *o, const char *name, upb_status *s) {
-  UPB_ASSERT(!upb_oneofdef_isfrozen(o));
-  if (upb_oneofdef_containingtype(o)) {
-    upb_status_seterrmsg(s, "oneof already added to a message");
-    return false;
-  }
-
-  if (!upb_isident(name, strlen(name), true, s)) {
-    return false;
-  }
-
-  name = upb_gstrdup(name);
-  if (!name) {
-    upb_status_seterrmsg(s, "One of memory");
-    return false;
-  }
-
-  upb_gfree((void*)o->name);
-  o->name = name;
-  return true;
+const char *upb_oneofdef_name(const upb_oneofdef *o) {
+  return shortdefname(o->full_name);
 }
 
 const upb_msgdef *upb_oneofdef_containingtype(const upb_oneofdef *o) {
@@ -2870,81 +1895,6 @@
   return o->index;
 }
 
-bool upb_oneofdef_addfield(upb_oneofdef *o, upb_fielddef *f,
-                           const void *ref_donor,
-                           upb_status *s) {
-  UPB_ASSERT(!upb_oneofdef_isfrozen(o));
-  UPB_ASSERT(!o->parent || !upb_msgdef_isfrozen(o->parent));
-
-  /* This method is idempotent. Check if |f| is already part of this oneofdef
-   * and return immediately if so. */
-  if (upb_fielddef_containingoneof(f) == o) {
-    return true;
-  }
-
-  /* The field must have an OPTIONAL label. */
-  if (upb_fielddef_label(f) != UPB_LABEL_OPTIONAL) {
-    upb_status_seterrmsg(s, "fields in oneof must have OPTIONAL label");
-    return false;
-  }
-
-  /* Check that no field with this name or number exists already in the oneof.
-   * Also check that the field is not already part of a oneof. */
-  if (upb_fielddef_name(f) == NULL || upb_fielddef_number(f) == 0) {
-    upb_status_seterrmsg(s, "field name or number were not set");
-    return false;
-  } else if (upb_oneofdef_itof(o, upb_fielddef_number(f)) ||
-             upb_oneofdef_ntofz(o, upb_fielddef_name(f))) {
-    upb_status_seterrmsg(s, "duplicate field name or number");
-    return false;
-  } else if (upb_fielddef_containingoneof(f) != NULL) {
-    upb_status_seterrmsg(s, "fielddef already belongs to a oneof");
-    return false;
-  }
-
-  /* We allow adding a field to the oneof either if the field is not part of a
-   * msgdef, or if it is and we are also part of the same msgdef. */
-  if (o->parent == NULL) {
-    /* If we're not in a msgdef, the field cannot be either. Otherwise we would
-     * need to magically add this oneof to a msgdef to remain consistent, which
-     * is surprising behavior. */
-    if (upb_fielddef_containingtype(f) != NULL) {
-      upb_status_seterrmsg(s, "fielddef already belongs to a message, but "
-                              "oneof does not");
-      return false;
-    }
-  } else {
-    /* If we're in a msgdef, the user can add fields that either aren't in any
-     * msgdef (in which case they're added to our msgdef) or already a part of
-     * our msgdef. */
-    if (upb_fielddef_containingtype(f) != NULL &&
-        upb_fielddef_containingtype(f) != o->parent) {
-      upb_status_seterrmsg(s, "fielddef belongs to a different message "
-                              "than oneof");
-      return false;
-    }
-  }
-
-  /* Commit phase. First add the field to our parent msgdef, if any, because
-   * that may fail; then add the field to our own tables. */
-
-  if (o->parent != NULL && upb_fielddef_containingtype(f) == NULL) {
-    if (!upb_msgdef_addfield((upb_msgdef*)o->parent, f, NULL, s)) {
-      return false;
-    }
-  }
-
-  release_containingtype(f);
-  f->oneof = o;
-  upb_inttable_insert(&o->itof, upb_fielddef_number(f), upb_value_ptr(f));
-  upb_strtable_insert(&o->ntof, upb_fielddef_name(f), upb_value_ptr(f));
-  upb_ref2(f, o);
-  upb_ref2(o, f);
-  if (ref_donor) upb_fielddef_unref(f, ref_donor);
-
-  return true;
-}
-
 const upb_fielddef *upb_oneofdef_ntof(const upb_oneofdef *o,
                                       const char *name, size_t length) {
   upb_value val;
@@ -2971,81 +1921,778 @@
 }
 
 upb_fielddef *upb_oneof_iter_field(const upb_oneof_iter *iter) {
-  return (upb_fielddef*)upb_value_getptr(upb_inttable_iter_value(iter));
+  return (upb_fielddef *)upb_value_getconstptr(upb_inttable_iter_value(iter));
 }
 
 void upb_oneof_iter_setdone(upb_oneof_iter *iter) {
   upb_inttable_iter_setdone(iter);
 }
 
+/* Code to build defs from descriptor protos. *********************************/
+
+/* There is a question of how much validation to do here.  It will be difficult
+ * to perfectly match the amount of validation performed by proto2.  But since
+ * this code is used to directly build defs from Ruby (for example) we do need
+ * to validate important constraints like uniqueness of names and numbers. */
+
+#define CHK(x) if (!(x)) { return false; }
+#define CHK_OOM(x) if (!(x)) { upb_status_setoom(ctx->status); return false; }
+
+typedef struct {
+  const upb_symtab *symtab;
+  upb_filedef *file;  /* File we are building. */
+  upb_alloc *alloc;    /* Allocate defs here. */
+  upb_alloc *tmp;      /* Alloc for addtab and any other tmp data. */
+  upb_strtable *addtab;  /* full_name -> packed def ptr for new defs. */
+  upb_status *status;  /* Record errors here. */
+} symtab_addctx;
+
+static char* strviewdup(const symtab_addctx *ctx, upb_strview view) {
+  return upb_strdup2(view.data, view.size, ctx->alloc);
+}
+
+static bool streql2(const char *a, size_t n, const char *b) {
+  return n == strlen(b) && memcmp(a, b, n) == 0;
+}
+
+static bool streql_view(upb_strview view, const char *b) {
+  return streql2(view.data, view.size, b);
+}
+
+static const char *makefullname(const symtab_addctx *ctx, const char *prefix,
+                                upb_strview name) {
+  if (prefix) {
+    /* ret = prefix + '.' + name; */
+    size_t n = strlen(prefix);
+    char *ret = upb_malloc(ctx->alloc, n + name.size + 2);
+    CHK_OOM(ret);
+    strcpy(ret, prefix);
+    ret[n] = '.';
+    memcpy(&ret[n + 1], name.data, name.size);
+    ret[n + 1 + name.size] = '\0';
+    return ret;
+  } else {
+    return strviewdup(ctx, name);
+  }
+}
+
+static bool symtab_add(const symtab_addctx *ctx, const char *name,
+                       upb_value v) {
+  upb_value tmp;
+  if (upb_strtable_lookup(ctx->addtab, name, &tmp) ||
+      upb_strtable_lookup(&ctx->symtab->syms, name, &tmp)) {
+    upb_status_seterrf(ctx->status, "duplicate symbol '%s'", name);
+    return false;
+  }
+
+  CHK_OOM(upb_strtable_insert3(ctx->addtab, name, strlen(name), v, ctx->tmp));
+  return true;
+}
+
+/* Given a symbol and the base symbol inside which it is defined, find the
+ * symbol's definition in t. */
+static bool resolvename(const upb_strtable *t, const upb_fielddef *f,
+                        const char *base, upb_strview sym,
+                        upb_deftype_t type, upb_status *status,
+                        const void **def) {
+  if(sym.size == 0) return NULL;
+  if(sym.data[0] == '.') {
+    /* Symbols starting with '.' are absolute, so we do a single lookup.
+     * Slice to omit the leading '.' */
+    upb_value v;
+    if (!upb_strtable_lookup2(t, sym.data + 1, sym.size - 1, &v)) {
+      return false;
+    }
+
+    *def = unpack_def(v, type);
+
+    if (!*def) {
+      upb_status_seterrf(status,
+                         "type mismatch when resolving field %s, name %s",
+                         f->full_name, sym.data);
+      return false;
+    }
+
+    return true;
+  } else {
+    /* Remove components from base until we find an entry or run out.
+     * TODO: This branch is totally broken, but currently not used. */
+    (void)base;
+    UPB_ASSERT(false);
+    return false;
+  }
+}
+
+const void *symtab_resolve(const symtab_addctx *ctx, const upb_fielddef *f,
+                           const char *base, upb_strview sym,
+                           upb_deftype_t type) {
+  const void *ret;
+  if (!resolvename(ctx->addtab, f, base, sym, type, ctx->status, &ret) &&
+      !resolvename(&ctx->symtab->syms, f, base, sym, type, ctx->status, &ret)) {
+    if (upb_ok(ctx->status)) {
+      upb_status_seterrf(ctx->status, "couldn't resolve name '%s'", sym.data);
+    }
+    return false;
+  }
+  return ret;
+}
+
+static bool create_oneofdef(
+    const symtab_addctx *ctx, upb_msgdef *m,
+    const google_protobuf_OneofDescriptorProto *oneof_proto) {
+  upb_oneofdef *o;
+  upb_strview name = google_protobuf_OneofDescriptorProto_name(oneof_proto);
+  upb_value v;
+
+  o = (upb_oneofdef*)&m->oneofs[m->oneof_count++];
+  o->parent = m;
+  o->full_name = makefullname(ctx, m->full_name, name);
+
+  v = pack_def(o, UPB_DEFTYPE_ONEOF);
+  CHK_OOM(symtab_add(ctx, o->full_name, v));
+  CHK_OOM(upb_strtable_insert3(&m->ntof, name.data, name.size, v, ctx->alloc));
+
+  CHK_OOM(upb_inttable_init2(&o->itof, UPB_CTYPE_CONSTPTR, ctx->alloc));
+  CHK_OOM(upb_strtable_init2(&o->ntof, UPB_CTYPE_CONSTPTR, ctx->alloc));
+
+  return true;
+}
+
+static bool parse_default(const symtab_addctx *ctx, const char *str, size_t len,
+                          upb_fielddef *f) {
+  char *end;
+  char nullz[64];
+  errno = 0;
+
+  switch (upb_fielddef_type(f)) {
+    case UPB_TYPE_INT32:
+    case UPB_TYPE_INT64:
+    case UPB_TYPE_UINT32:
+    case UPB_TYPE_UINT64:
+    case UPB_TYPE_DOUBLE:
+    case UPB_TYPE_FLOAT:
+      /* Standard C number parsing functions expect null-terminated strings. */
+      if (len >= sizeof(nullz) - 1) {
+        return false;
+      }
+      memcpy(nullz, str, len);
+      nullz[len] = '\0';
+      str = nullz;
+      break;
+    default:
+      break;
+  }
+
+  switch (upb_fielddef_type(f)) {
+    case UPB_TYPE_INT32: {
+      long val = strtol(str, &end, 0);
+      CHK(val <= INT32_MAX && val >= INT32_MIN && errno != ERANGE && !*end);
+      f->defaultval.sint = val;
+      break;
+    }
+    case UPB_TYPE_ENUM: {
+      const upb_enumdef *e = f->sub.enumdef;
+      int32_t val;
+      CHK(upb_enumdef_ntoi(e, str, len, &val));
+      f->defaultval.sint = val;
+      break;
+    }
+    case UPB_TYPE_INT64: {
+      /* XXX: Need to write our own strtoll, since it's not available in c89. */
+      long long val = strtol(str, &end, 0);
+      CHK(val <= INT64_MAX && val >= INT64_MIN && errno != ERANGE && !*end);
+      f->defaultval.sint = val;
+      break;
+    }
+    case UPB_TYPE_UINT32: {
+      unsigned long val = strtoul(str, &end, 0);
+      CHK(val <= UINT32_MAX && errno != ERANGE && !*end);
+      f->defaultval.uint = val;
+      break;
+    }
+    case UPB_TYPE_UINT64: {
+      /* XXX: Need to write our own strtoull, since it's not available in c89. */
+      unsigned long long val = strtoul(str, &end, 0);
+      CHK(val <= UINT64_MAX && errno != ERANGE && !*end);
+      f->defaultval.uint = val;
+      break;
+    }
+    case UPB_TYPE_DOUBLE: {
+      double val = strtod(str, &end);
+      CHK(errno != ERANGE && !*end);
+      f->defaultval.dbl = val;
+      break;
+    }
+    case UPB_TYPE_FLOAT: {
+      /* XXX: Need to write our own strtof, since it's not available in c89. */
+      float val = strtod(str, &end);
+      CHK(errno != ERANGE && !*end);
+      f->defaultval.flt = val;
+      break;
+    }
+    case UPB_TYPE_BOOL: {
+      if (streql2(str, len, "false")) {
+        f->defaultval.boolean = false;
+      } else if (streql2(str, len, "true")) {
+        f->defaultval.boolean = true;
+      } else {
+        return false;
+      }
+    }
+    case UPB_TYPE_STRING:
+      f->defaultval.str = newstr(ctx->alloc, str, len);
+      break;
+    case UPB_TYPE_BYTES:
+      /* XXX: need to interpret the C-escaped value. */
+      f->defaultval.str = newstr(ctx->alloc, str, len);
+      break;
+    case UPB_TYPE_MESSAGE:
+      /* Should not have a default value. */
+      return false;
+  }
+  return true;
+}
+
+static void set_default_default(const symtab_addctx *ctx, upb_fielddef *f) {
+  switch (upb_fielddef_type(f)) {
+    case UPB_TYPE_INT32:
+    case UPB_TYPE_INT64:
+    case UPB_TYPE_ENUM:
+      f->defaultval.sint = 0;
+      break;
+    case UPB_TYPE_UINT64:
+    case UPB_TYPE_UINT32:
+      f->defaultval.uint = 0;
+      break;
+    case UPB_TYPE_DOUBLE:
+    case UPB_TYPE_FLOAT:
+      f->defaultval.dbl = 0;
+      break;
+    case UPB_TYPE_STRING:
+    case UPB_TYPE_BYTES:
+      f->defaultval.str = newstr(ctx->alloc, NULL, 0);
+      break;
+    case UPB_TYPE_BOOL:
+      f->defaultval.boolean = false;
+      break;
+    case UPB_TYPE_MESSAGE:
+      break;
+  }
+}
+
+static bool create_fielddef(
+    const symtab_addctx *ctx, const char *prefix, upb_msgdef *m,
+    const google_protobuf_FieldDescriptorProto *field_proto) {
+  upb_alloc *alloc = ctx->alloc;
+  upb_fielddef *f;
+  const google_protobuf_FieldOptions *options;
+  upb_strview name;
+  const char *full_name;
+  const char *shortname;
+  uint32_t field_number;
+
+  if (!google_protobuf_FieldDescriptorProto_has_name(field_proto)) {
+    upb_status_seterrmsg(ctx->status, "field has no name");
+    return false;
+  }
+
+  name = google_protobuf_FieldDescriptorProto_name(field_proto);
+  CHK(upb_isident(name, false, ctx->status));
+  full_name = makefullname(ctx, prefix, name);
+  shortname = shortdefname(full_name);
+
+  field_number = google_protobuf_FieldDescriptorProto_number(field_proto);
+
+  if (field_number == 0 || field_number > UPB_MAX_FIELDNUMBER) {
+    upb_status_seterrf(ctx->status, "invalid field number (%u)", field_number);
+    return false;
+  }
+
+  if (m) {
+    /* direct message field. */
+    upb_value v, packed_v;
+
+    f = (upb_fielddef*)&m->fields[m->field_count++];
+    f->msgdef = m;
+    f->is_extension_ = false;
+
+    packed_v = pack_def(f, UPB_DEFTYPE_FIELD);
+    v = upb_value_constptr(f);
+
+    if (!upb_strtable_insert3(&m->ntof, name.data, name.size, packed_v, alloc)) {
+      upb_status_seterrf(ctx->status, "duplicate field name (%s)", shortname);
+      return false;
+    }
+
+    if (!upb_inttable_insert2(&m->itof, field_number, v, alloc)) {
+      upb_status_seterrf(ctx->status, "duplicate field number (%u)",
+                         field_number);
+      return false;
+    }
+  } else {
+    /* extension field. */
+    f = (upb_fielddef*)&ctx->file->exts[ctx->file->ext_count];
+    f->is_extension_ = true;
+    CHK_OOM(symtab_add(ctx, full_name, pack_def(f, UPB_DEFTYPE_FIELD)));
+  }
+
+  f->full_name = full_name;
+  f->file = ctx->file;
+  f->type_ = (int)google_protobuf_FieldDescriptorProto_type(field_proto);
+  f->label_ = (int)google_protobuf_FieldDescriptorProto_label(field_proto);
+  f->number_ = field_number;
+  f->oneof = NULL;
+
+  /* We can't resolve the subdef or (in the case of extensions) the containing
+   * message yet, because it may not have been defined yet.  We stash a pointer
+   * to the field_proto until later when we can properly resolve it. */
+  f->sub.unresolved = field_proto;
+
+  if (f->label_ == UPB_LABEL_REQUIRED && f->file->syntax == UPB_SYNTAX_PROTO3) {
+    upb_status_seterrf(ctx->status, "proto3 fields cannot be required (%s)",
+                       f->full_name);
+    return false;
+  }
+
+  if (google_protobuf_FieldDescriptorProto_has_oneof_index(field_proto)) {
+    int oneof_index =
+        google_protobuf_FieldDescriptorProto_oneof_index(field_proto);
+    upb_oneofdef *oneof;
+    upb_value v = upb_value_constptr(f);
+
+    if (upb_fielddef_label(f) != UPB_LABEL_OPTIONAL) {
+      upb_status_seterrf(ctx->status,
+                         "fields in oneof must have OPTIONAL label (%s)",
+                         f->full_name);
+      return false;
+    }
+
+    if (!m) {
+      upb_status_seterrf(ctx->status,
+                         "oneof_index provided for extension field (%s)",
+                         f->full_name);
+      return false;
+    }
+
+    if (oneof_index >= m->oneof_count) {
+      upb_status_seterrf(ctx->status, "oneof_index out of range (%s)",
+                         f->full_name);
+      return false;
+    }
+
+    oneof = (upb_oneofdef*)&m->oneofs[oneof_index];
+    f->oneof = oneof;
+
+    CHK(upb_inttable_insert2(&oneof->itof, f->number_, v, alloc));
+    CHK(upb_strtable_insert3(&oneof->ntof, name.data, name.size, v, alloc));
+  } else {
+    f->oneof = NULL;
+  }
+
+  if (google_protobuf_FieldDescriptorProto_has_options(field_proto)) {
+    options = google_protobuf_FieldDescriptorProto_options(field_proto);
+    f->lazy_ = google_protobuf_FieldOptions_lazy(options);
+    f->packed_ = google_protobuf_FieldOptions_packed(options);
+  } else {
+    f->lazy_ = false;
+    f->packed_ = false;
+  }
+
+  return true;
+}
+
+static bool create_enumdef(
+    const symtab_addctx *ctx, const char *prefix,
+    const google_protobuf_EnumDescriptorProto *enum_proto) {
+  upb_enumdef *e;
+  const google_protobuf_EnumValueDescriptorProto *const *values;
+  upb_strview name;
+  size_t i, n;
+
+  name = google_protobuf_EnumDescriptorProto_name(enum_proto);
+  CHK(upb_isident(name, false, ctx->status));
+
+  e = (upb_enumdef*)&ctx->file->enums[ctx->file->enum_count++];
+  e->full_name = makefullname(ctx, prefix, name);
+  CHK_OOM(symtab_add(ctx, e->full_name, pack_def(e, UPB_DEFTYPE_ENUM)));
+
+  CHK_OOM(upb_strtable_init2(&e->ntoi, UPB_CTYPE_INT32, ctx->alloc));
+  CHK_OOM(upb_inttable_init2(&e->iton, UPB_CTYPE_CSTR, ctx->alloc));
+
+  e->file = ctx->file;
+  e->defaultval = 0;
+
+  values = google_protobuf_EnumDescriptorProto_value(enum_proto, &n);
+
+  if (n == 0) {
+    upb_status_seterrf(ctx->status,
+                       "enums must contain at least one value (%s)",
+                       e->full_name);
+    return false;
+  }
+
+  for (i = 0; i < n; i++) {
+    const google_protobuf_EnumValueDescriptorProto *value = values[i];
+    upb_strview name = google_protobuf_EnumValueDescriptorProto_name(value);
+    char *name2 = strviewdup(ctx, name);
+    int32_t num = google_protobuf_EnumValueDescriptorProto_number(value);
+    upb_value v = upb_value_int32(num);
+
+    if (i == 0 && e->file->syntax == UPB_SYNTAX_PROTO3 && num != 0) {
+      upb_status_seterrf(ctx->status,
+                         "for proto3, the first enum value must be zero (%s)",
+                         e->full_name);
+      return false;
+    }
+
+    if (upb_strtable_lookup(&e->ntoi, name2, NULL)) {
+      upb_status_seterrf(ctx->status, "duplicate enum label '%s'", name2);
+      return false;
+    }
+
+    CHK_OOM(name2)
+    CHK_OOM(
+        upb_strtable_insert3(&e->ntoi, name2, strlen(name2), v, ctx->alloc));
+
+    if (!upb_inttable_lookup(&e->iton, num, NULL)) {
+      upb_value v = upb_value_cstr(name2);
+      CHK_OOM(upb_inttable_insert2(&e->iton, num, v, ctx->alloc));
+    }
+  }
+
+  upb_inttable_compact2(&e->iton, ctx->alloc);
+
+  return true;
+}
+
+static bool create_msgdef(const symtab_addctx *ctx, const char *prefix,
+                          const google_protobuf_DescriptorProto *msg_proto) {
+  upb_msgdef *m;
+  const google_protobuf_MessageOptions *options;
+  const google_protobuf_OneofDescriptorProto *const *oneofs;
+  const google_protobuf_FieldDescriptorProto *const *fields;
+  const google_protobuf_EnumDescriptorProto *const *enums;
+  const google_protobuf_DescriptorProto *const *msgs;
+  size_t i, n;
+  upb_strview name;
+
+  name = google_protobuf_DescriptorProto_name(msg_proto);
+  CHK(upb_isident(name, false, ctx->status));
+
+  m = (upb_msgdef*)&ctx->file->msgs[ctx->file->msg_count++];
+  m->full_name = makefullname(ctx, prefix, name);
+  CHK_OOM(symtab_add(ctx, m->full_name, pack_def(m, UPB_DEFTYPE_MSG)));
+
+  CHK_OOM(upb_inttable_init2(&m->itof, UPB_CTYPE_CONSTPTR, ctx->alloc));
+  CHK_OOM(upb_strtable_init2(&m->ntof, UPB_CTYPE_CONSTPTR, ctx->alloc));
+
+  m->file = ctx->file;
+  m->map_entry = false;
+
+  options = google_protobuf_DescriptorProto_options(msg_proto);
+
+  if (options) {
+    m->map_entry = google_protobuf_MessageOptions_map_entry(options);
+  }
+
+  oneofs = google_protobuf_DescriptorProto_oneof_decl(msg_proto, &n);
+  m->oneof_count = 0;
+  m->oneofs = upb_malloc(ctx->alloc, sizeof(*m->oneofs) * n);
+  for (i = 0; i < n; i++) {
+    CHK(create_oneofdef(ctx, m, oneofs[i]));
+  }
+
+  fields = google_protobuf_DescriptorProto_field(msg_proto, &n);
+  m->field_count = 0;
+  m->fields = upb_malloc(ctx->alloc, sizeof(*m->fields) * n);
+  for (i = 0; i < n; i++) {
+    CHK(create_fielddef(ctx, m->full_name, m, fields[i]));
+  }
+
+  CHK(assign_msg_indices(m, ctx->status));
+  assign_msg_wellknowntype(m);
+  upb_inttable_compact2(&m->itof, ctx->alloc);
+
+  /* This message is built.  Now build nested messages and enums. */
+
+  enums = google_protobuf_DescriptorProto_enum_type(msg_proto, &n);
+  for (i = 0; i < n; i++) {
+    CHK(create_enumdef(ctx, m->full_name, enums[i]));
+  }
+
+  msgs = google_protobuf_DescriptorProto_nested_type(msg_proto, &n);
+  for (i = 0; i < n; i++) {
+    CHK(create_msgdef(ctx, m->full_name, msgs[i]));
+  }
+
+  return true;
+}
+
+typedef struct {
+  int msg_count;
+  int enum_count;
+  int ext_count;
+} decl_counts;
+
+static void count_types_in_msg(const google_protobuf_DescriptorProto *msg_proto,
+                               decl_counts *counts) {
+  const google_protobuf_DescriptorProto *const *msgs;
+  size_t i, n;
+
+  counts->msg_count++;
+
+  msgs = google_protobuf_DescriptorProto_nested_type(msg_proto, &n);
+  for (i = 0; i < n; i++) {
+    count_types_in_msg(msgs[i], counts);
+  }
+
+  google_protobuf_DescriptorProto_enum_type(msg_proto, &n);
+  counts->enum_count += n;
+
+  google_protobuf_DescriptorProto_extension(msg_proto, &n);
+  counts->ext_count += n;
+}
+
+static void count_types_in_file(
+    const google_protobuf_FileDescriptorProto *file_proto,
+    decl_counts *counts) {
+  const google_protobuf_DescriptorProto *const *msgs;
+  size_t i, n;
+
+  msgs = google_protobuf_FileDescriptorProto_message_type(file_proto, &n);
+  for (i = 0; i < n; i++) {
+    count_types_in_msg(msgs[i], counts);
+  }
+
+  google_protobuf_FileDescriptorProto_enum_type(file_proto, &n);
+  counts->enum_count += n;
+
+  google_protobuf_FileDescriptorProto_extension(file_proto, &n);
+  counts->ext_count += n;
+}
+
+static bool resolve_fielddef(const symtab_addctx *ctx, const char *prefix,
+                             upb_fielddef *f) {
+  upb_strview name;
+  const google_protobuf_FieldDescriptorProto *field_proto = f->sub.unresolved;
+
+  if (f->is_extension_) {
+    if (!google_protobuf_FieldDescriptorProto_has_extendee(field_proto)) {
+      upb_status_seterrf(ctx->status,
+                         "extension for field '%s' had no extendee",
+                         f->full_name);
+      return false;
+    }
+
+    name = google_protobuf_FieldDescriptorProto_extendee(field_proto);
+    f->msgdef = symtab_resolve(ctx, f, prefix, name, UPB_DEFTYPE_MSG);
+    CHK(f->msgdef);
+  }
+
+  if ((upb_fielddef_issubmsg(f) || f->type_ == UPB_DESCRIPTOR_TYPE_ENUM) &&
+      !google_protobuf_FieldDescriptorProto_has_type_name(field_proto)) {
+    upb_status_seterrf(ctx->status, "field '%s' is missing type name",
+                       f->full_name);
+    return false;
+  }
+
+  name = google_protobuf_FieldDescriptorProto_type_name(field_proto);
+
+  if (upb_fielddef_issubmsg(f)) {
+    f->sub.msgdef = symtab_resolve(ctx, f, prefix, name, UPB_DEFTYPE_MSG);
+    CHK(f->sub.msgdef);
+  } else if (f->type_ == UPB_DESCRIPTOR_TYPE_ENUM) {
+    f->sub.enumdef = symtab_resolve(ctx, f, prefix, name, UPB_DEFTYPE_ENUM);
+    CHK(f->sub.enumdef);
+  }
+
+  /* Have to delay resolving of the default value until now because of the enum
+   * case, since enum defaults are specified with a label. */
+  if (google_protobuf_FieldDescriptorProto_has_default_value(field_proto)) {
+    upb_strview defaultval =
+        google_protobuf_FieldDescriptorProto_default_value(field_proto);
+
+    if (f->file->syntax == UPB_SYNTAX_PROTO3) {
+      upb_status_seterrf(ctx->status,
+                         "proto3 fields cannot have explicit defaults (%s)",
+                         f->full_name);
+      return false;
+    }
+
+    if (upb_fielddef_issubmsg(f)) {
+      upb_status_seterrf(ctx->status,
+                         "message fields cannot have explicit defaults (%s)",
+                         f->full_name);
+      return false;
+    }
+
+    if (!parse_default(ctx, defaultval.data, defaultval.size, f)) {
+      upb_status_seterrf(ctx->status,
+                         "couldn't parse default '" UPB_STRVIEW_FORMAT
+                         "' for field (%s)",
+                         UPB_STRVIEW_ARGS(defaultval), f->full_name);
+      return false;
+    }
+  } else {
+    set_default_default(ctx, f);
+  }
+
+  return true;
+}
+
+static bool build_filedef(
+    const symtab_addctx *ctx, upb_filedef *file,
+    const google_protobuf_FileDescriptorProto *file_proto) {
+  upb_alloc *alloc = ctx->alloc;
+  const google_protobuf_FileOptions *file_options_proto;
+  const google_protobuf_DescriptorProto *const *msgs;
+  const google_protobuf_EnumDescriptorProto *const *enums;
+  const google_protobuf_FieldDescriptorProto *const *exts;
+  const upb_strview* strs;
+  size_t i, n;
+  decl_counts counts = {0};
+
+  count_types_in_file(file_proto, &counts);
+
+  file->msgs = upb_malloc(alloc, sizeof(*file->msgs) * counts.msg_count);
+  file->enums = upb_malloc(alloc, sizeof(*file->enums) * counts.enum_count);
+  file->exts = upb_malloc(alloc, sizeof(*file->exts) * counts.ext_count);
+
+  CHK_OOM(counts.msg_count == 0 || file->msgs);
+  CHK_OOM(counts.enum_count == 0 || file->enums);
+  CHK_OOM(counts.ext_count == 0 || file->exts);
+
+  /* We increment these as defs are added. */
+  file->msg_count = 0;
+  file->enum_count = 0;
+  file->ext_count = 0;
+
+  if (!google_protobuf_FileDescriptorProto_has_name(file_proto)) {
+    upb_status_seterrmsg(ctx->status, "File has no name");
+    return false;
+  }
+
+  file->name =
+      strviewdup(ctx, google_protobuf_FileDescriptorProto_name(file_proto));
+  file->phpprefix = NULL;
+  file->phpnamespace = NULL;
+
+  if (google_protobuf_FileDescriptorProto_has_package(file_proto)) {
+    upb_strview package =
+        google_protobuf_FileDescriptorProto_package(file_proto);
+    CHK(upb_isident(package, true, ctx->status));
+    file->package = strviewdup(ctx, package);
+  } else {
+    file->package = NULL;
+  }
+
+  if (google_protobuf_FileDescriptorProto_has_syntax(file_proto)) {
+    upb_strview syntax =
+        google_protobuf_FileDescriptorProto_syntax(file_proto);
+
+    if (streql_view(syntax, "proto2")) {
+      file->syntax = UPB_SYNTAX_PROTO2;
+    } else if (streql_view(syntax, "proto3")) {
+      file->syntax = UPB_SYNTAX_PROTO3;
+    } else {
+      upb_status_seterrf(ctx->status, "Invalid syntax '%s'", syntax);
+      return false;
+    }
+  } else {
+    file->syntax = UPB_SYNTAX_PROTO2;
+  }
+
+  /* Read options. */
+  file_options_proto = google_protobuf_FileDescriptorProto_options(file_proto);
+  if (file_options_proto) {
+    if (google_protobuf_FileOptions_has_php_class_prefix(file_options_proto)) {
+      file->phpprefix = strviewdup(
+          ctx,
+          google_protobuf_FileOptions_php_class_prefix(file_options_proto));
+    }
+    if (google_protobuf_FileOptions_has_php_namespace(file_options_proto)) {
+      file->phpnamespace = strviewdup(
+          ctx, google_protobuf_FileOptions_php_namespace(file_options_proto));
+    }
+  }
+
+  /* Verify dependencies. */
+  strs = google_protobuf_FileDescriptorProto_dependency(file_proto, &n);
+  file->deps = upb_malloc(alloc, sizeof(*file->deps) * n) ;
+  CHK_OOM(n == 0 || file->deps);
+
+  for (i = 0; i < n; i++) {
+    upb_strview dep_name = strs[i];
+    upb_value v;
+    if (!upb_strtable_lookup2(&ctx->symtab->files, dep_name.data,
+                              dep_name.size, &v)) {
+      upb_status_seterrf(ctx->status,
+                         "Depends on file '" UPB_STRVIEW_FORMAT
+                         "', but it has not been loaded",
+                         UPB_STRVIEW_ARGS(dep_name));
+      return false;
+    }
+    file->deps[i] = upb_value_getconstptr(v);
+  }
+
+  /* Create messages. */
+  msgs = google_protobuf_FileDescriptorProto_message_type(file_proto, &n);
+  for (i = 0; i < n; i++) {
+    CHK(create_msgdef(ctx, file->package, msgs[i]));
+  }
+
+  /* Create enums. */
+  enums = google_protobuf_FileDescriptorProto_enum_type(file_proto, &n);
+  for (i = 0; i < n; i++) {
+    CHK(create_enumdef(ctx, file->package, enums[i]));
+  }
+
+  /* Create extensions. */
+  exts = google_protobuf_FileDescriptorProto_extension(file_proto, &n);
+  file->exts = upb_malloc(alloc, sizeof(*file->exts) * n);
+  CHK_OOM(n == 0 || file->exts);
+  for (i = 0; i < n; i++) {
+    CHK(create_fielddef(ctx, file->package, NULL, exts[i]));
+  }
+
+  /* Now that all names are in the table, resolve references. */
+  for (i = 0; i < file->ext_count; i++) {
+    CHK(resolve_fielddef(ctx, file->package, (upb_fielddef*)&file->exts[i]));
+  }
+
+  for (i = 0; i < file->msg_count; i++) {
+    const upb_msgdef *m = &file->msgs[i];
+    int j;
+    for (j = 0; j < m->field_count; j++) {
+      CHK(resolve_fielddef(ctx, m->full_name, (upb_fielddef*)&m->fields[j]));
+    }
+  }
+
+  return true;
+ }
+
+static bool upb_symtab_addtotabs(upb_symtab *s, symtab_addctx *ctx,
+                                 upb_status *status) {
+  const upb_filedef *file = ctx->file;
+  upb_alloc *alloc = upb_arena_alloc(s->arena);
+  upb_strtable_iter iter;
+
+  CHK_OOM(upb_strtable_insert3(&s->files, file->name, strlen(file->name),
+                               upb_value_constptr(file), alloc));
+
+  upb_strtable_begin(&iter, ctx->addtab);
+  for (; !upb_strtable_done(&iter); upb_strtable_next(&iter)) {
+    const char *key = upb_strtable_iter_key(&iter);
+    size_t keylen = upb_strtable_iter_keylength(&iter);
+    upb_value value = upb_strtable_iter_value(&iter);
+    CHK_OOM(upb_strtable_insert3(&s->syms, key, keylen, value, alloc));
+  }
+
+  return true;
+}
+
 /* upb_filedef ****************************************************************/
 
-static void visitfiledef(const upb_refcounted *r, upb_refcounted_visit *visit,
-                         void *closure) {
-  const upb_filedef *f = (const upb_filedef*)r;
-  size_t i;
-
-  for(i = 0; i < upb_filedef_defcount(f); i++) {
-    visit(r, upb_def_upcast(upb_filedef_def(f, i)), closure);
-  }
-}
-
-static void freefiledef(upb_refcounted *r) {
-  upb_filedef *f = (upb_filedef*)r;
-  size_t i;
-
-  for(i = 0; i < upb_filedef_depcount(f); i++) {
-    upb_filedef_unref(upb_filedef_dep(f, i), f);
-  }
-
-  upb_inttable_uninit(&f->defs);
-  upb_inttable_uninit(&f->deps);
-  upb_gfree((void*)f->name);
-  upb_gfree((void*)f->package);
-  upb_gfree((void*)f->phpprefix);
-  upb_gfree((void*)f->phpnamespace);
-  upb_gfree(f);
-}
-
-const struct upb_refcounted_vtbl upb_filedef_vtbl = {visitfiledef, freefiledef};
-
-upb_filedef *upb_filedef_new(const void *owner) {
-  upb_filedef *f = upb_gmalloc(sizeof(*f));
-
-  if (!f) {
-    return NULL;
-  }
-
-  f->package = NULL;
-  f->name = NULL;
-  f->phpprefix = NULL;
-  f->phpnamespace = NULL;
-  f->syntax = UPB_SYNTAX_PROTO2;
-
-  if (!upb_refcounted_init(upb_filedef_upcast_mutable(f), &upb_filedef_vtbl,
-                           owner)) {
-    goto err;
-  }
-
-  if (!upb_inttable_init(&f->defs, UPB_CTYPE_CONSTPTR)) {
-    goto err;
-  }
-
-  if (!upb_inttable_init(&f->deps, UPB_CTYPE_CONSTPTR)) {
-    goto err2;
-  }
-
-  return f;
-
-
-err2:
-  upb_inttable_uninit(&f->defs);
-
-err:
-  upb_gfree(f);
-  return NULL;
-}
-
 const char *upb_filedef_name(const upb_filedef *f) {
   return f->name;
 }
@@ -3066,453 +2713,157 @@
   return f->syntax;
 }
 
-size_t upb_filedef_defcount(const upb_filedef *f) {
-  return upb_inttable_count(&f->defs);
+int upb_filedef_msgcount(const upb_filedef *f) {
+  return f->msg_count;
 }
 
-size_t upb_filedef_depcount(const upb_filedef *f) {
-  return upb_inttable_count(&f->deps);
+int upb_filedef_depcount(const upb_filedef *f) {
+  return f->dep_count;
 }
 
-const upb_def *upb_filedef_def(const upb_filedef *f, size_t i) {
-  upb_value v;
-
-  if (upb_inttable_lookup32(&f->defs, i, &v)) {
-    return upb_value_getconstptr(v);
-  } else {
-    return NULL;
-  }
+int upb_filedef_enumcount(const upb_filedef *f) {
+  return f->enum_count;
 }
 
-const upb_filedef *upb_filedef_dep(const upb_filedef *f, size_t i) {
-  upb_value v;
-
-  if (upb_inttable_lookup32(&f->deps, i, &v)) {
-    return upb_value_getconstptr(v);
-  } else {
-    return NULL;
-  }
+const upb_filedef *upb_filedef_dep(const upb_filedef *f, int i) {
+  return i < 0 || i >= f->dep_count ? NULL : f->deps[i];
 }
 
-bool upb_filedef_setname(upb_filedef *f, const char *name, upb_status *s) {
-  name = upb_gstrdup(name);
-  if (!name) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-  upb_gfree((void*)f->name);
-  f->name = name;
-  return true;
+const upb_msgdef *upb_filedef_msg(const upb_filedef *f, int i) {
+  return i < 0 || i >= f->msg_count ? NULL : &f->msgs[i];
 }
 
-bool upb_filedef_setpackage(upb_filedef *f, const char *package,
-                            upb_status *s) {
-  if (!upb_isident(package, strlen(package), true, s)) return false;
-  package = upb_gstrdup(package);
-  if (!package) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-  upb_gfree((void*)f->package);
-  f->package = package;
-  return true;
-}
-
-bool upb_filedef_setphpprefix(upb_filedef *f, const char *phpprefix,
-                              upb_status *s) {
-  phpprefix = upb_gstrdup(phpprefix);
-  if (!phpprefix) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-  upb_gfree((void*)f->phpprefix);
-  f->phpprefix = phpprefix;
-  return true;
-}
-
-bool upb_filedef_setphpnamespace(upb_filedef *f, const char *phpnamespace,
-                                 upb_status *s) {
-  phpnamespace = upb_gstrdup(phpnamespace);
-  if (!phpnamespace) {
-    upb_upberr_setoom(s);
-    return false;
-  }
-  upb_gfree((void*)f->phpnamespace);
-  f->phpnamespace = phpnamespace;
-  return true;
-}
-
-bool upb_filedef_setsyntax(upb_filedef *f, upb_syntax_t syntax,
-                           upb_status *s) {
-  UPB_UNUSED(s);
-  if (syntax != UPB_SYNTAX_PROTO2 &&
-      syntax != UPB_SYNTAX_PROTO3) {
-    upb_status_seterrmsg(s, "Unknown syntax value.");
-    return false;
-  }
-  f->syntax = syntax;
-
-  {
-    /* Set all messages in this file to match. */
-    size_t i;
-    for (i = 0; i < upb_filedef_defcount(f); i++) {
-      /* Casting const away is safe since all defs in mutable filedef must
-       * also be mutable. */
-      upb_def *def = (upb_def*)upb_filedef_def(f, i);
-
-      upb_msgdef *m = upb_dyncast_msgdef_mutable(def);
-      if (m) {
-        m->syntax = syntax;
-      }
-    }
-  }
-
-  return true;
-}
-
-bool upb_filedef_adddef(upb_filedef *f, upb_def *def, const void *ref_donor,
-                        upb_status *s) {
-  if (def->file) {
-    upb_status_seterrmsg(s, "Def is already part of another filedef.");
-    return false;
-  }
-
-  if (upb_inttable_push(&f->defs, upb_value_constptr(def))) {
-    def->file = f;
-    upb_ref2(def, f);
-    upb_ref2(f, def);
-    if (ref_donor) upb_def_unref(def, ref_donor);
-    if (def->type == UPB_DEF_MSG) {
-      upb_downcast_msgdef_mutable(def)->syntax = f->syntax;
-    }
-    return true;
-  } else {
-    upb_upberr_setoom(s);
-    return false;
-  }
-}
-
-bool upb_filedef_adddep(upb_filedef *f, const upb_filedef *dep) {
-  if (upb_inttable_push(&f->deps, upb_value_constptr(dep))) {
-    /* Regular ref instead of ref2 because files can't form cycles. */
-    upb_filedef_ref(dep, f);
-    return true;
-  } else {
-    return false;
-  }
+const upb_enumdef *upb_filedef_enum(const upb_filedef *f, int i) {
+  return i < 0 || i >= f->enum_count ? NULL : &f->enums[i];
 }
 
 void upb_symtab_free(upb_symtab *s) {
-  upb_strtable_iter i;
-  upb_strtable_begin(&i, &s->symtab);
-  for (; !upb_strtable_done(&i); upb_strtable_next(&i)) {
-    const upb_def *def = upb_value_getptr(upb_strtable_iter_value(&i));
-    upb_def_unref(def, s);
-  }
-  upb_strtable_uninit(&s->symtab);
+  upb_arena_free(s->arena);
   upb_gfree(s);
 }
 
 upb_symtab *upb_symtab_new() {
   upb_symtab *s = upb_gmalloc(sizeof(*s));
+  upb_alloc *alloc;
+
   if (!s) {
     return NULL;
   }
 
-  upb_strtable_init(&s->symtab, UPB_CTYPE_PTR);
-  return s;
-}
+  s->arena = upb_arena_new();
+  alloc = upb_arena_alloc(s->arena);
 
-const upb_def *upb_symtab_lookup(const upb_symtab *s, const char *sym) {
-  upb_value v;
-  upb_def *ret = upb_strtable_lookup(&s->symtab, sym, &v) ?
-      upb_value_getptr(v) : NULL;
-  return ret;
+  if (!upb_strtable_init2(&s->syms, UPB_CTYPE_CONSTPTR, alloc) ||
+      !upb_strtable_init2(&s->files, UPB_CTYPE_CONSTPTR, alloc)) {
+    upb_arena_free(s->arena);
+    upb_gfree(s);
+    s = NULL;
+  }
+  return s;
 }
 
 const upb_msgdef *upb_symtab_lookupmsg(const upb_symtab *s, const char *sym) {
   upb_value v;
-  upb_def *def = upb_strtable_lookup(&s->symtab, sym, &v) ?
-      upb_value_getptr(v) : NULL;
-  return def ? upb_dyncast_msgdef(def) : NULL;
+  return upb_strtable_lookup(&s->syms, sym, &v) ?
+      unpack_def(v, UPB_DEFTYPE_MSG) : NULL;
 }
 
 const upb_msgdef *upb_symtab_lookupmsg2(const upb_symtab *s, const char *sym,
                                         size_t len) {
   upb_value v;
-  upb_def *def = upb_strtable_lookup2(&s->symtab, sym, len, &v) ?
-      upb_value_getptr(v) : NULL;
-  return def ? upb_dyncast_msgdef(def) : NULL;
+  return upb_strtable_lookup2(&s->syms, sym, len, &v) ?
+      unpack_def(v, UPB_DEFTYPE_MSG) : NULL;
 }
 
 const upb_enumdef *upb_symtab_lookupenum(const upb_symtab *s, const char *sym) {
   upb_value v;
-  upb_def *def = upb_strtable_lookup(&s->symtab, sym, &v) ?
-      upb_value_getptr(v) : NULL;
-  return def ? upb_dyncast_enumdef(def) : NULL;
+  return upb_strtable_lookup(&s->syms, sym, &v) ?
+      unpack_def(v, UPB_DEFTYPE_ENUM) : NULL;
 }
 
-/* Given a symbol and the base symbol inside which it is defined, find the
- * symbol's definition in t. */
-static upb_def *upb_resolvename(const upb_strtable *t,
-                                const char *base, const char *sym) {
-  if(strlen(sym) == 0) return NULL;
-  if(sym[0] == '.') {
-    /* Symbols starting with '.' are absolute, so we do a single lookup.
-     * Slice to omit the leading '.' */
-    upb_value v;
-    return upb_strtable_lookup(t, sym + 1, &v) ? upb_value_getptr(v) : NULL;
-  } else {
-    /* Remove components from base until we find an entry or run out.
-     * TODO: This branch is totally broken, but currently not used. */
-    (void)base;
-    UPB_ASSERT(false);
-    return NULL;
-  }
+const upb_filedef *upb_symtab_lookupfile(const upb_symtab *s, const char *name) {
+  upb_value v;
+  return upb_strtable_lookup(&s->files, name, &v) ? upb_value_getconstptr(v)
+                                                  : NULL;
 }
 
-const upb_def *upb_symtab_resolve(const upb_symtab *s, const char *base,
-                                  const char *sym) {
-  upb_def *ret = upb_resolvename(&s->symtab, base, sym);
-  return ret;
-}
-
-/* TODO(haberman): we need a lot more testing of error conditions. */
-static bool symtab_add(upb_symtab *s, upb_def *const*defs, size_t n,
-                       void *ref_donor, upb_refcounted *freeze_also,
-                       upb_status *status) {
-  size_t i;
-  size_t add_n;
-  size_t freeze_n;
-  upb_strtable_iter iter;
-  upb_refcounted **add_objs = NULL;
-  upb_def **add_defs = NULL;
-  size_t add_objs_size;
+const upb_filedef *upb_symtab_addfile(
+    upb_symtab *s, const google_protobuf_FileDescriptorProto *file_proto,
+    upb_status *status) {
+  upb_arena *tmparena = upb_arena_new();
   upb_strtable addtab;
+  upb_alloc *alloc = upb_arena_alloc(s->arena);
+  upb_filedef *file = upb_malloc(alloc, sizeof(*file));
+  bool ok;
+  symtab_addctx ctx;
 
-  if (n == 0 && !freeze_also) {
+  ctx.file = file;
+  ctx.symtab = s;
+  ctx.alloc = alloc;
+  ctx.tmp = upb_arena_alloc(tmparena);
+  ctx.addtab = &addtab;
+  ctx.status = status;
+
+  ok = file &&
+      upb_strtable_init2(&addtab, UPB_CTYPE_CONSTPTR, ctx.tmp) &&
+      build_filedef(&ctx, file, file_proto) &&
+      upb_symtab_addtotabs(s, &ctx, status);
+
+  upb_arena_free(tmparena);
+  return ok ? file : NULL;
+}
+
+/* Include here since we want most of this file to be stdio-free. */
+#include <stdio.h>
+
+bool _upb_symtab_loaddefinit(upb_symtab *s, const upb_def_init *init) {
+  /* Since this function should never fail (it would indicate a bug in upb) we
+   * print errors to stderr instead of returning error status to the user. */
+  upb_def_init **deps = init->deps;
+  google_protobuf_FileDescriptorProto *file;
+  upb_arena *arena;
+  upb_status status;
+
+  upb_status_clear(&status);
+
+  if (upb_strtable_lookup(&s->files, init->filename, NULL)) {
     return true;
   }
 
-  if (!upb_strtable_init(&addtab, UPB_CTYPE_PTR)) {
-    upb_status_seterrmsg(status, "out of memory");
-    return false;
+  arena = upb_arena_new();
+
+  for (; *deps; deps++) {
+    if (!_upb_symtab_loaddefinit(s, *deps)) goto err;
   }
 
-  /* Add new defs to our "add" set. */
-  for (i = 0; i < n; i++) {
-    upb_def *def = defs[i];
-    const char *fullname;
-    upb_fielddef *f;
+  file = google_protobuf_FileDescriptorProto_parsenew(init->descriptor, arena);
 
-    if (upb_def_isfrozen(def)) {
-      upb_status_seterrmsg(status, "added defs must be mutable");
-      goto err;
-    }
-    UPB_ASSERT(!upb_def_isfrozen(def));
-    fullname = upb_def_fullname(def);
-    if (!fullname) {
-      upb_status_seterrmsg(
-          status, "Anonymous defs cannot be added to a symtab");
-      goto err;
-    }
-
-    f = upb_dyncast_fielddef_mutable(def);
-
-    if (f) {
-      if (!upb_fielddef_containingtypename(f)) {
-        upb_status_seterrmsg(status,
-                             "Standalone fielddefs must have a containing type "
-                             "(extendee) name set");
-        goto err;
-      }
-    } else {
-      if (upb_strtable_lookup(&addtab, fullname, NULL)) {
-        upb_status_seterrf(status, "Conflicting defs named '%s'", fullname);
-        goto err;
-      }
-      if (upb_strtable_lookup(&s->symtab, fullname, NULL)) {
-        upb_status_seterrf(status, "Symtab already has a def named '%s'",
-                           fullname);
-        goto err;
-      }
-      if (!upb_strtable_insert(&addtab, fullname, upb_value_ptr(def)))
-        goto oom_err;
-      upb_def_donateref(def, ref_donor, s);
-    }
-
-    if (upb_dyncast_fielddef_mutable(def)) {
-      /* TODO(haberman): allow adding extensions attached to files. */
-      upb_status_seterrf(status, "Can't add extensions to symtab.\n");
-      goto err;
-    }
-  }
-
-  /* Now using the table, resolve symbolic references for subdefs. */
-  upb_strtable_begin(&iter, &addtab);
-  for (; !upb_strtable_done(&iter); upb_strtable_next(&iter)) {
-    const char *base;
-    upb_def *def = upb_value_getptr(upb_strtable_iter_value(&iter));
-    upb_msgdef *m = upb_dyncast_msgdef_mutable(def);
-    upb_msg_field_iter j;
-
-    if (!m) continue;
-    /* Type names are resolved relative to the message in which they appear. */
-    base = upb_msgdef_fullname(m);
-
-    for(upb_msg_field_begin(&j, m);
-        !upb_msg_field_done(&j);
-        upb_msg_field_next(&j)) {
-      upb_fielddef *f = upb_msg_iter_field(&j);
-      const char *name = upb_fielddef_subdefname(f);
-      if (name && !upb_fielddef_subdef(f)) {
-        /* Try the lookup in the current set of to-be-added defs first. If not
-         * there, try existing defs. */
-        upb_def *subdef = upb_resolvename(&addtab, base, name);
-        if (subdef == NULL) {
-          subdef = upb_resolvename(&s->symtab, base, name);
-        }
-        if (subdef == NULL) {
-          upb_status_seterrf(
-              status, "couldn't resolve name '%s' in message '%s'", name, base);
-          goto err;
-        } else if (!upb_fielddef_setsubdef(f, subdef, status)) {
-          goto err;
-        }
-      }
-    }
-  }
-
-  /* We need an array of the defs in addtab, for passing to
-   * upb_refcounted_freeze(). */
-  add_objs_size = upb_strtable_count(&addtab);
-  if (freeze_also) {
-    add_objs_size++;
-  }
-
-  add_defs = upb_gmalloc(sizeof(void*) * add_objs_size);
-  if (add_defs == NULL) goto oom_err;
-  upb_strtable_begin(&iter, &addtab);
-  for (add_n = 0; !upb_strtable_done(&iter); upb_strtable_next(&iter)) {
-    add_defs[add_n++] = upb_value_getptr(upb_strtable_iter_value(&iter));
-  }
-
-  /* Validate defs. */
-  if (!_upb_def_validate(add_defs, add_n, status)) {
+  if (!file) {
+    upb_status_seterrf(
+        &status,
+        "Failed to parse compiled-in descriptor for file '%s'. This should "
+        "never happen.",
+        init->filename);
     goto err;
   }
 
-  /* Cheat a little and give the array a new type.
-   * This is probably undefined behavior, but this code will be deleted soon. */
-  add_objs = (upb_refcounted**)add_defs;
+  if (!upb_symtab_addfile(s, file, &status)) goto err;
 
-  freeze_n = add_n;
-  if (freeze_also) {
-    add_objs[freeze_n++] = freeze_also;
-  }
-
-  if (!upb_refcounted_freeze(add_objs, freeze_n, status,
-                             UPB_MAX_MESSAGE_DEPTH * 2)) {
-    goto err;
-  }
-
-  /* This must be delayed until all errors have been detected, since error
-   * recovery code uses this table to cleanup defs. */
-  upb_strtable_uninit(&addtab);
-
-  /* TODO(haberman) we don't properly handle errors after this point (like
-   * OOM in upb_strtable_insert() below). */
-  for (i = 0; i < add_n; i++) {
-    upb_def *def = (upb_def*)add_objs[i];
-    const char *name = upb_def_fullname(def);
-    bool success;
-    success = upb_strtable_insert(&s->symtab, name, upb_value_ptr(def));
-    UPB_ASSERT(success);
-  }
-  upb_gfree(add_defs);
+  upb_arena_free(arena);
   return true;
 
-oom_err:
-  upb_status_seterrmsg(status, "out of memory");
-err: {
-    /* We need to donate the refs back. */
-    upb_strtable_begin(&iter, &addtab);
-    for (; !upb_strtable_done(&iter); upb_strtable_next(&iter)) {
-      upb_def *def = upb_value_getptr(upb_strtable_iter_value(&iter));
-      upb_def_donateref(def, s, ref_donor);
-    }
-  }
-  upb_strtable_uninit(&addtab);
-  upb_gfree(add_defs);
-  UPB_ASSERT(!upb_ok(status));
+err:
+  fprintf(stderr, "Error loading compiled-in descriptor: %s\n",
+          upb_status_errmsg(&status));
+  upb_arena_free(arena);
   return false;
 }
 
-bool upb_symtab_add(upb_symtab *s, upb_def *const*defs, size_t n,
-                    void *ref_donor, upb_status *status) {
-  return symtab_add(s, defs, n, ref_donor, NULL, status);
-}
-
-bool upb_symtab_addfile(upb_symtab *s, upb_filedef *file, upb_status *status) {
-  size_t n;
-  size_t i;
-  upb_def **defs;
-  bool ret;
-
-  n = upb_filedef_defcount(file);
-  if (n == 0) {
-    return true;
-  }
-  defs = upb_gmalloc(sizeof(*defs) * n);
-
-  if (defs == NULL) {
-    upb_status_seterrmsg(status, "Out of memory");
-    return false;
-  }
-
-  for (i = 0; i < n; i++) {
-    defs[i] = upb_filedef_mutabledef(file, i);
-  }
-
-  ret = symtab_add(s, defs, n, NULL, upb_filedef_upcast_mutable(file), status);
-
-  upb_gfree(defs);
-  return ret;
-}
-
-/* Iteration. */
-
-static void advance_to_matching(upb_symtab_iter *iter) {
-  if (iter->type == UPB_DEF_ANY)
-    return;
-
-  while (!upb_strtable_done(&iter->iter) &&
-         iter->type != upb_symtab_iter_def(iter)->type) {
-    upb_strtable_next(&iter->iter);
-  }
-}
-
-void upb_symtab_begin(upb_symtab_iter *iter, const upb_symtab *s,
-                      upb_deftype_t type) {
-  upb_strtable_begin(&iter->iter, &s->symtab);
-  iter->type = type;
-  advance_to_matching(iter);
-}
-
-void upb_symtab_next(upb_symtab_iter *iter) {
-  upb_strtable_next(&iter->iter);
-  advance_to_matching(iter);
-}
-
-bool upb_symtab_done(const upb_symtab_iter *iter) {
-  return upb_strtable_done(&iter->iter);
-}
-
-const upb_def *upb_symtab_iter_def(const upb_symtab_iter *iter) {
-  return upb_value_getptr(upb_strtable_iter_value(&iter->iter));
-}
+#undef CHK
+#undef CHK_OOM
 /* We encode backwards, to avoid pre-computing lengths (one-pass encode). */
 
+#include <string.h>
 
 #define UPB_PB_VARINT_MAX_LEN 10
 #define CHK(x) do { if (!(x)) { return false; } } while(0)
@@ -3717,8 +3068,8 @@
       VARINT_CASE(int64_t, upb_zzencode_64(*ptr));
     case UPB_DESCRIPTOR_TYPE_STRING:
     case UPB_DESCRIPTOR_TYPE_BYTES: {
-      upb_stringview *start = arr->data;
-      upb_stringview *ptr = start + arr->len;
+      upb_strview *start = arr->data;
+      upb_strview *ptr = start + arr->len;
       do {
         ptr--;
         CHK(upb_put_bytes(e, ptr->data, ptr->size) &&
@@ -3802,7 +3153,7 @@
       CASE(int64_t, varint, UPB_WIRE_TYPE_VARINT, upb_zzencode_64(val));
     case UPB_DESCRIPTOR_TYPE_STRING:
     case UPB_DESCRIPTOR_TYPE_BYTES: {
-      upb_stringview view = *(upb_stringview*)field_mem;
+      upb_strview view = *(upb_strview*)field_mem;
       if (skip_zero_value && view.size == 0) {
         return true;
       }
@@ -3913,8 +3264,17 @@
 #include <string.h>
 
 
-static void *upb_calloc(size_t size) {
-  void *mem = upb_gmalloc(size);
+
+struct upb_handlers {
+  upb_handlercache *cache;
+  const upb_msgdef *msg;
+  const upb_handlers **sub;
+  const void *top_closure_type;
+  upb_handlers_tabent table[1];  /* Dynamically-sized field handler array. */
+};
+
+static void *upb_calloc(upb_arena *arena, size_t size) {
+  void *mem = upb_malloc(upb_arena_alloc(arena), size);
   if (mem) {
     memset(mem, 0, size);
   }
@@ -3925,111 +3285,23 @@
  * UPB_NO_CLOSURE. */
 char _upb_noclosure;
 
-static void freehandlers(upb_refcounted *r) {
-  upb_handlers *h = (upb_handlers*)r;
-
-  upb_inttable_iter i;
-  upb_inttable_begin(&i, &h->cleanup_);
-  for(; !upb_inttable_done(&i); upb_inttable_next(&i)) {
-    void *val = (void*)upb_inttable_iter_key(&i);
-    upb_value func_val = upb_inttable_iter_value(&i);
-    upb_handlerfree *func = upb_value_getfptr(func_val);
-    func(val);
-  }
-
-  upb_inttable_uninit(&h->cleanup_);
-  upb_msgdef_unref(h->msg, h);
-  upb_gfree(h->sub);
-  upb_gfree(h);
-}
-
-static void visithandlers(const upb_refcounted *r, upb_refcounted_visit *visit,
-                          void *closure) {
-  const upb_handlers *h = (const upb_handlers*)r;
-  upb_msg_field_iter i;
-  for(upb_msg_field_begin(&i, h->msg);
-      !upb_msg_field_done(&i);
-      upb_msg_field_next(&i)) {
-    upb_fielddef *f = upb_msg_iter_field(&i);
-    const upb_handlers *sub;
-    if (!upb_fielddef_issubmsg(f)) continue;
-    sub = upb_handlers_getsubhandlers(h, f);
-    if (sub) visit(r, upb_handlers_upcast(sub), closure);
-  }
-}
-
-static const struct upb_refcounted_vtbl vtbl = {visithandlers, freehandlers};
-
-typedef struct {
-  upb_inttable tab;  /* maps upb_msgdef* -> upb_handlers*. */
-  upb_handlers_callback *callback;
-  const void *closure;
-} dfs_state;
-
-/* TODO(haberman): discard upb_handlers* objects that do not actually have any
- * handlers set and cannot reach any upb_handlers* object that does.  This is
- * slightly tricky to do correctly. */
-static upb_handlers *newformsg(const upb_msgdef *m, const void *owner,
-                               dfs_state *s) {
-  upb_msg_field_iter i;
-  upb_handlers *h = upb_handlers_new(m, owner);
-  if (!h) return NULL;
-  if (!upb_inttable_insertptr(&s->tab, m, upb_value_ptr(h))) goto oom;
-
-  s->callback(s->closure, h);
-
-  /* For each submessage field, get or create a handlers object and set it as
-   * the subhandlers. */
-  for(upb_msg_field_begin(&i, m);
-      !upb_msg_field_done(&i);
-      upb_msg_field_next(&i)) {
-    upb_fielddef *f = upb_msg_iter_field(&i);
-    const upb_msgdef *subdef;
-    upb_value subm_ent;
-
-    if (!upb_fielddef_issubmsg(f)) continue;
-
-    subdef = upb_downcast_msgdef(upb_fielddef_subdef(f));
-    if (upb_inttable_lookupptr(&s->tab, subdef, &subm_ent)) {
-      upb_handlers_setsubhandlers(h, f, upb_value_getptr(subm_ent));
-    } else {
-      upb_handlers *sub_mh = newformsg(subdef, &sub_mh, s);
-      if (!sub_mh) goto oom;
-      upb_handlers_setsubhandlers(h, f, sub_mh);
-      upb_handlers_unref(sub_mh, &sub_mh);
-    }
-  }
-  return h;
-
-oom:
-  upb_handlers_unref(h, owner);
-  return NULL;
-}
-
 /* Given a selector for a STARTSUBMSG handler, resolves to a pointer to the
  * subhandlers for this submessage field. */
 #define SUBH(h, selector) (h->sub[selector])
 
 /* The selector for a submessage field is the field index. */
-#define SUBH_F(h, f) SUBH(h, f->index_)
+#define SUBH_F(h, f) SUBH(h, upb_fielddef_index(f))
 
 static int32_t trygetsel(upb_handlers *h, const upb_fielddef *f,
                          upb_handlertype_t type) {
   upb_selector_t sel;
-  UPB_ASSERT(!upb_handlers_isfrozen(h));
-  if (upb_handlers_msgdef(h) != upb_fielddef_containingtype(f)) {
-    upb_status_seterrf(
-        &h->status_, "type mismatch: field %s does not belong to message %s",
-        upb_fielddef_name(f), upb_msgdef_fullname(upb_handlers_msgdef(h)));
-    return -1;
-  }
-  if (!upb_handlers_getselector(f, type, &sel)) {
-    upb_status_seterrf(
-        &h->status_,
-        "type mismatch: cannot register handler type %d for field %s",
-        type, upb_fielddef_name(f));
-    return -1;
-  }
+  bool ok;
+
+  ok = upb_handlers_getselector(f, type, &sel);
+
+  UPB_ASSERT(upb_handlers_msgdef(h) == upb_fielddef_containingtype(f));
+  UPB_ASSERT(ok);
+
   return sel;
 }
 
@@ -4042,29 +3314,17 @@
 
 static const void **returntype(upb_handlers *h, const upb_fielddef *f,
                                upb_handlertype_t type) {
-  return &h->table[handlers_getsel(h, f, type)].attr.return_closure_type_;
+  return &h->table[handlers_getsel(h, f, type)].attr.return_closure_type;
 }
 
 static bool doset(upb_handlers *h, int32_t sel, const upb_fielddef *f,
                   upb_handlertype_t type, upb_func *func,
-                  upb_handlerattr *attr) {
-  upb_handlerattr set_attr = UPB_HANDLERATTR_INITIALIZER;
+                  const upb_handlerattr *attr) {
+  upb_handlerattr set_attr = UPB_HANDLERATTR_INIT;
   const void *closure_type;
   const void **context_closure_type;
 
-  UPB_ASSERT(!upb_handlers_isfrozen(h));
-
-  if (sel < 0) {
-    upb_status_seterrmsg(&h->status_,
-                         "incorrect handler type for this field.");
-    return false;
-  }
-
-  if (h->table[sel].func) {
-    upb_status_seterrmsg(&h->status_,
-                         "cannot change handler once it has been set.");
-    return false;
-  }
+  UPB_ASSERT(!h->table[sel].func);
 
   if (attr) {
     set_attr = *attr;
@@ -4072,7 +3332,7 @@
 
   /* Check that the given closure type matches the closure type that has been
    * established for this context (if any). */
-  closure_type = upb_handlerattr_closuretype(&set_attr);
+  closure_type = set_attr.closure_type;
 
   if (type == UPB_HANDLER_STRING) {
     context_closure_type = returntype(h, f, UPB_HANDLER_STARTSTR);
@@ -4086,15 +3346,6 @@
 
   if (closure_type && *context_closure_type &&
       closure_type != *context_closure_type) {
-    /* TODO(haberman): better message for debugging. */
-    if (f) {
-      upb_status_seterrf(&h->status_,
-                         "closure type does not match for field %s",
-                         upb_fielddef_name(f));
-    } else {
-      upb_status_seterrmsg(
-          &h->status_, "closure type does not match for message-level handler");
-    }
     return false;
   }
 
@@ -4104,16 +3355,15 @@
   /* If this is a STARTSEQ or STARTSTR handler, check that the returned pointer
    * matches any pre-existing expectations about what type is expected. */
   if (type == UPB_HANDLER_STARTSEQ || type == UPB_HANDLER_STARTSTR) {
-    const void *return_type = upb_handlerattr_returnclosuretype(&set_attr);
-    const void *table_return_type =
-        upb_handlerattr_returnclosuretype(&h->table[sel].attr);
+    const void *return_type = set_attr.return_closure_type;
+    const void *table_return_type = h->table[sel].attr.return_closure_type;
     if (return_type && table_return_type && return_type != table_return_type) {
-      upb_status_seterrmsg(&h->status_, "closure return type does not match");
       return false;
     }
 
-    if (table_return_type && !return_type)
-      upb_handlerattr_setreturnclosuretype(&set_attr, table_return_type);
+    if (table_return_type && !return_type) {
+      set_attr.return_closure_type = table_return_type;
+    }
   }
 
   h->table[sel].func = (upb_func*)func;
@@ -4139,18 +3389,18 @@
       type != UPB_HANDLER_STARTSEQ &&
       type != UPB_HANDLER_ENDSEQ &&
       h->table[sel = handlers_getsel(h, f, UPB_HANDLER_STARTSEQ)].func) {
-    ret = upb_handlerattr_returnclosuretype(&h->table[sel].attr);
+    ret = h->table[sel].attr.return_closure_type;
   }
 
   if (type == UPB_HANDLER_STRING &&
       h->table[sel = handlers_getsel(h, f, UPB_HANDLER_STARTSTR)].func) {
-    ret = upb_handlerattr_returnclosuretype(&h->table[sel].attr);
+    ret = h->table[sel].attr.return_closure_type;
   }
 
   /* The effective type of the submessage; not used yet.
    * if (type == SUBMESSAGE &&
    *     h->table[sel = handlers_getsel(h, f, UPB_HANDLER_STARTSUBMSG)].func) {
-   *   ret = upb_handlerattr_returnclosuretype(&h->table[sel].attr);
+   *   ret = h->table[sel].attr.return_closure_type;
    * } */
 
   return ret;
@@ -4170,92 +3420,47 @@
   if (h->table[sel].func) return true;
   closure_type = effective_closure_type(h, f, type);
   attr = &h->table[sel].attr;
-  return_closure_type = upb_handlerattr_returnclosuretype(attr);
+  return_closure_type = attr->return_closure_type;
   if (closure_type && return_closure_type &&
       closure_type != return_closure_type) {
-    upb_status_seterrf(status,
-                       "expected start handler to return sub type for field %f",
-                       upb_fielddef_name(f));
     return false;
   }
   return true;
 }
 
-/* Public interface ***********************************************************/
-
-upb_handlers *upb_handlers_new(const upb_msgdef *md, const void *owner) {
+static upb_handlers *upb_handlers_new(const upb_msgdef *md,
+                                      upb_handlercache *cache,
+                                      upb_arena *arena) {
   int extra;
   upb_handlers *h;
 
-  UPB_ASSERT(upb_msgdef_isfrozen(md));
-
-  extra = sizeof(upb_handlers_tabent) * (md->selector_count - 1);
-  h = upb_calloc(sizeof(*h) + extra);
+  extra = sizeof(upb_handlers_tabent) * (upb_msgdef_selectorcount(md) - 1);
+  h = upb_calloc(arena, sizeof(*h) + extra);
   if (!h) return NULL;
 
+  h->cache = cache;
   h->msg = md;
-  upb_msgdef_ref(h->msg, h);
-  upb_status_clear(&h->status_);
 
-  if (md->submsg_field_count > 0) {
-    h->sub = upb_calloc(md->submsg_field_count * sizeof(*h->sub));
-    if (!h->sub) goto oom;
+  if (upb_msgdef_submsgfieldcount(md) > 0) {
+    size_t bytes = upb_msgdef_submsgfieldcount(md) * sizeof(*h->sub);
+    h->sub = upb_calloc(arena, bytes);
+    if (!h->sub) return NULL;
   } else {
     h->sub = 0;
   }
 
-  if (!upb_refcounted_init(upb_handlers_upcast_mutable(h), &vtbl, owner))
-    goto oom;
-  if (!upb_inttable_init(&h->cleanup_, UPB_CTYPE_FPTR)) goto oom;
-
   /* calloc() above initialized all handlers to NULL. */
   return h;
-
-oom:
-  freehandlers(upb_handlers_upcast_mutable(h));
-  return NULL;
 }
 
-const upb_handlers *upb_handlers_newfrozen(const upb_msgdef *m,
-                                           const void *owner,
-                                           upb_handlers_callback *callback,
-                                           const void *closure) {
-  dfs_state state;
-  upb_handlers *ret;
-  bool ok;
-  upb_refcounted *r;
+/* Public interface ***********************************************************/
 
-  state.callback = callback;
-  state.closure = closure;
-  if (!upb_inttable_init(&state.tab, UPB_CTYPE_PTR)) return NULL;
-
-  ret = newformsg(m, owner, &state);
-
-  upb_inttable_uninit(&state.tab);
-  if (!ret) return NULL;
-
-  r = upb_handlers_upcast_mutable(ret);
-  ok = upb_refcounted_freeze(&r, 1, NULL, UPB_MAX_HANDLER_DEPTH);
-  UPB_ASSERT(ok);
-
-  return ret;
-}
-
-const upb_status *upb_handlers_status(upb_handlers *h) {
-  UPB_ASSERT(!upb_handlers_isfrozen(h));
-  return &h->status_;
-}
-
-void upb_handlers_clearerr(upb_handlers *h) {
-  UPB_ASSERT(!upb_handlers_isfrozen(h));
-  upb_status_clear(&h->status_);
-}
-
-#define SETTER(name, handlerctype, handlertype) \
-  bool upb_handlers_set ## name(upb_handlers *h, const upb_fielddef *f, \
-                                handlerctype func, upb_handlerattr *attr) { \
-    int32_t sel = trygetsel(h, f, handlertype); \
-    return doset(h, sel, f, handlertype, (upb_func*)func, attr); \
+#define SETTER(name, handlerctype, handlertype)                       \
+  bool upb_handlers_set##name(upb_handlers *h, const upb_fielddef *f, \
+                              handlerctype func,                      \
+                              const upb_handlerattr *attr) {          \
+    int32_t sel = trygetsel(h, f, handlertype);                       \
+    return doset(h, sel, f, handlertype, (upb_func *)func, attr);     \
   }
 
 SETTER(int32,       upb_int32_handlerfunc*,       UPB_HANDLER_INT32)
@@ -4276,20 +3481,19 @@
 #undef SETTER
 
 bool upb_handlers_setunknown(upb_handlers *h, upb_unknown_handlerfunc *func,
-                             upb_handlerattr *attr) {
+                             const upb_handlerattr *attr) {
   return doset(h, UPB_UNKNOWN_SELECTOR, NULL, UPB_HANDLER_INT32,
                (upb_func *)func, attr);
 }
 
 bool upb_handlers_setstartmsg(upb_handlers *h, upb_startmsg_handlerfunc *func,
-                              upb_handlerattr *attr) {
+                              const upb_handlerattr *attr) {
   return doset(h, UPB_STARTMSG_SELECTOR, NULL, UPB_HANDLER_INT32,
                (upb_func *)func, attr);
 }
 
 bool upb_handlers_setendmsg(upb_handlers *h, upb_endmsg_handlerfunc *func,
-                            upb_handlerattr *attr) {
-  UPB_ASSERT(!upb_handlers_isfrozen(h));
+                            const upb_handlerattr *attr) {
   return doset(h, UPB_ENDMSG_SELECTOR, NULL, UPB_HANDLER_INT32,
                (upb_func *)func, attr);
 }
@@ -4297,14 +3501,12 @@
 bool upb_handlers_setsubhandlers(upb_handlers *h, const upb_fielddef *f,
                                  const upb_handlers *sub) {
   UPB_ASSERT(sub);
-  UPB_ASSERT(!upb_handlers_isfrozen(h));
   UPB_ASSERT(upb_fielddef_issubmsg(f));
   if (SUBH_F(h, f)) return false;  /* Can't reset. */
-  if (upb_msgdef_upcast(upb_handlers_msgdef(sub)) != upb_fielddef_subdef(f)) {
+  if (upb_handlers_msgdef(sub) != upb_fielddef_msgsubdef(f)) {
     return false;
   }
   SUBH_F(h, f) = sub;
-  upb_ref2(sub, h);
   return true;
 }
 
@@ -4314,9 +3516,18 @@
   return SUBH_F(h, f);
 }
 
+upb_func *upb_handlers_gethandler(const upb_handlers *h, upb_selector_t s,
+                                  const void **handler_data) {
+  upb_func *ret = (upb_func *)h->table[s].func;
+  if (ret && handler_data) {
+    *handler_data = h->table[s].attr.handler_data;
+  }
+  return ret;
+}
+
 bool upb_handlers_getattr(const upb_handlers *h, upb_selector_t sel,
                           upb_handlerattr *attr) {
-  if (!upb_handlers_gethandler(h, sel))
+  if (!upb_handlers_gethandler(h, sel, NULL))
     return false;
   *attr = h->table[sel].attr;
   return true;
@@ -4331,100 +3542,7 @@
 const upb_msgdef *upb_handlers_msgdef(const upb_handlers *h) { return h->msg; }
 
 bool upb_handlers_addcleanup(upb_handlers *h, void *p, upb_handlerfree *func) {
-  bool ok;
-  if (upb_inttable_lookupptr(&h->cleanup_, p, NULL)) {
-    return false;
-  }
-  ok = upb_inttable_insertptr(&h->cleanup_, p, upb_value_fptr(func));
-  UPB_ASSERT(ok);
-  return true;
-}
-
-
-/* "Static" methods ***********************************************************/
-
-bool upb_handlers_freeze(upb_handlers *const*handlers, int n, upb_status *s) {
-  /* TODO: verify we have a transitive closure. */
-  int i;
-  for (i = 0; i < n; i++) {
-    upb_msg_field_iter j;
-    upb_handlers *h = handlers[i];
-
-    if (!upb_ok(&h->status_)) {
-      upb_status_seterrf(s, "handlers for message %s had error status: %s",
-                         upb_msgdef_fullname(upb_handlers_msgdef(h)),
-                         upb_status_errmsg(&h->status_));
-      return false;
-    }
-
-    /* Check that there are no closure mismatches due to missing Start* handlers
-     * or subhandlers with different type-level types. */
-    for(upb_msg_field_begin(&j, h->msg);
-        !upb_msg_field_done(&j);
-        upb_msg_field_next(&j)) {
-
-      const upb_fielddef *f = upb_msg_iter_field(&j);
-      if (upb_fielddef_isseq(f)) {
-        if (!checkstart(h, f, UPB_HANDLER_STARTSEQ, s))
-          return false;
-      }
-
-      if (upb_fielddef_isstring(f)) {
-        if (!checkstart(h, f, UPB_HANDLER_STARTSTR, s))
-          return false;
-      }
-
-      if (upb_fielddef_issubmsg(f)) {
-        bool hashandler = false;
-        if (upb_handlers_gethandler(
-                h, handlers_getsel(h, f, UPB_HANDLER_STARTSUBMSG)) ||
-            upb_handlers_gethandler(
-                h, handlers_getsel(h, f, UPB_HANDLER_ENDSUBMSG))) {
-          hashandler = true;
-        }
-
-        if (upb_fielddef_isseq(f) &&
-            (upb_handlers_gethandler(
-                 h, handlers_getsel(h, f, UPB_HANDLER_STARTSEQ)) ||
-             upb_handlers_gethandler(
-                 h, handlers_getsel(h, f, UPB_HANDLER_ENDSEQ)))) {
-          hashandler = true;
-        }
-
-        if (hashandler && !upb_handlers_getsubhandlers(h, f)) {
-          /* For now we add an empty subhandlers in this case.  It makes the
-           * decoder code generator simpler, because it only has to handle two
-           * cases (submessage has handlers or not) as opposed to three
-           * (submessage has handlers in enclosing message but no subhandlers).
-           *
-           * This makes parsing less efficient in the case that we want to
-           * notice a submessage but skip its contents (like if we're testing
-           * for submessage presence or counting the number of repeated
-           * submessages).  In this case we will end up parsing the submessage
-           * field by field and throwing away the results for each, instead of
-           * skipping the whole delimited thing at once.  If this is an issue we
-           * can revisit it, but do remember that this only arises when you have
-           * handlers (startseq/startsubmsg/endsubmsg/endseq) set for the
-           * submessage but no subhandlers.  The uses cases for this are
-           * limited. */
-          upb_handlers *sub = upb_handlers_new(upb_fielddef_msgsubdef(f), &sub);
-          upb_handlers_setsubhandlers(h, f, sub);
-          upb_handlers_unref(sub, &sub);
-        }
-
-        /* TODO(haberman): check type of submessage.
-         * This is slightly tricky; also consider whether we should check that
-         * they match at setsubhandlers time. */
-      }
-    }
-  }
-
-  if (!upb_refcounted_freeze((upb_refcounted*const*)handlers, n, s,
-                             UPB_MAX_HANDLER_DEPTH)) {
-    return false;
-  }
-
-  return true;
+  return upb_handlercache_addcleanup(h->cache, p, func);
 }
 
 upb_handlertype_t upb_handlers_getprimitivehandlertype(const upb_fielddef *f) {
@@ -4443,6 +3561,7 @@
 
 bool upb_handlers_getselector(const upb_fielddef *f, upb_handlertype_t type,
                               upb_selector_t *s) {
+  uint32_t selector_base = upb_fielddef_selectorbase(f);
   switch (type) {
     case UPB_HANDLER_INT32:
     case UPB_HANDLER_INT64:
@@ -4454,38 +3573,38 @@
       if (!upb_fielddef_isprimitive(f) ||
           upb_handlers_getprimitivehandlertype(f) != type)
         return false;
-      *s = f->selector_base;
+      *s = selector_base;
       break;
     case UPB_HANDLER_STRING:
       if (upb_fielddef_isstring(f)) {
-        *s = f->selector_base;
+        *s = selector_base;
       } else if (upb_fielddef_lazy(f)) {
-        *s = f->selector_base + 3;
+        *s = selector_base + 3;
       } else {
         return false;
       }
       break;
     case UPB_HANDLER_STARTSTR:
       if (upb_fielddef_isstring(f) || upb_fielddef_lazy(f)) {
-        *s = f->selector_base + 1;
+        *s = selector_base + 1;
       } else {
         return false;
       }
       break;
     case UPB_HANDLER_ENDSTR:
       if (upb_fielddef_isstring(f) || upb_fielddef_lazy(f)) {
-        *s = f->selector_base + 2;
+        *s = selector_base + 2;
       } else {
         return false;
       }
       break;
     case UPB_HANDLER_STARTSEQ:
       if (!upb_fielddef_isseq(f)) return false;
-      *s = f->selector_base - 2;
+      *s = selector_base - 2;
       break;
     case UPB_HANDLER_ENDSEQ:
       if (!upb_fielddef_isseq(f)) return false;
-      *s = f->selector_base - 1;
+      *s = selector_base - 1;
       break;
     case UPB_HANDLER_STARTSUBMSG:
       if (!upb_fielddef_issubmsg(f)) return false;
@@ -4493,14 +3612,14 @@
        * selector can also be used as an index into the "sub" array of
        * subhandlers.  The indexes for the two into these two tables are the
        * same, except that in the handler table the static selectors come first. */
-      *s = f->index_ + UPB_STATIC_SELECTOR_COUNT;
+      *s = upb_fielddef_index(f) + UPB_STATIC_SELECTOR_COUNT;
       break;
     case UPB_HANDLER_ENDSUBMSG:
       if (!upb_fielddef_issubmsg(f)) return false;
-      *s = f->selector_base;
+      *s = selector_base;
       break;
   }
-  UPB_ASSERT((size_t)*s < upb_fielddef_containingtype(f)->selector_count);
+  UPB_ASSERT((size_t)*s < upb_msgdef_selectorcount(upb_fielddef_containingtype(f)));
   return true;
 }
 
@@ -4523,90 +3642,108 @@
   return ret;
 }
 
+/* upb_handlercache ***********************************************************/
 
-/* upb_handlerattr ************************************************************/
+struct upb_handlercache {
+  upb_arena *arena;
+  upb_inttable tab;  /* maps upb_msgdef* -> upb_handlers*. */
+  upb_handlers_callback *callback;
+  const void *closure;
+};
 
-void upb_handlerattr_init(upb_handlerattr *attr) {
-  upb_handlerattr from = UPB_HANDLERATTR_INITIALIZER;
-  memcpy(attr, &from, sizeof(*attr));
+const upb_handlers *upb_handlercache_get(upb_handlercache *c,
+                                         const upb_msgdef *md) {
+  upb_msg_field_iter i;
+  upb_value v;
+  upb_handlers *h;
+
+  if (upb_inttable_lookupptr(&c->tab, md, &v)) {
+    return upb_value_getptr(v);
+  }
+
+  h = upb_handlers_new(md, c, c->arena);
+  v = upb_value_ptr(h);
+
+  if (!h) return NULL;
+  if (!upb_inttable_insertptr(&c->tab, md, v)) return NULL;
+
+  c->callback(c->closure, h);
+
+  /* For each submessage field, get or create a handlers object and set it as
+   * the subhandlers. */
+  for(upb_msg_field_begin(&i, md);
+      !upb_msg_field_done(&i);
+      upb_msg_field_next(&i)) {
+    upb_fielddef *f = upb_msg_iter_field(&i);
+
+    if (upb_fielddef_issubmsg(f)) {
+      const upb_msgdef *subdef = upb_fielddef_msgsubdef(f);
+      const upb_handlers *sub_mh = upb_handlercache_get(c, subdef);
+
+      if (!sub_mh) return NULL;
+
+      upb_handlers_setsubhandlers(h, f, sub_mh);
+    }
+  }
+
+  return h;
 }
 
-void upb_handlerattr_uninit(upb_handlerattr *attr) {
-  UPB_UNUSED(attr);
+
+upb_handlercache *upb_handlercache_new(upb_handlers_callback *callback,
+                                       const void *closure) {
+  upb_handlercache *cache = upb_gmalloc(sizeof(*cache));
+
+  if (!cache) return NULL;
+
+  cache->arena = upb_arena_new();
+
+  cache->callback = callback;
+  cache->closure = closure;
+
+  if (!upb_inttable_init(&cache->tab, UPB_CTYPE_PTR)) goto oom;
+
+  return cache;
+
+oom:
+  upb_gfree(cache);
+  return NULL;
 }
 
-bool upb_handlerattr_sethandlerdata(upb_handlerattr *attr, const void *hd) {
-  attr->handler_data_ = hd;
-  return true;
+void upb_handlercache_free(upb_handlercache *cache) {
+  upb_inttable_uninit(&cache->tab);
+  upb_arena_free(cache->arena);
+  upb_gfree(cache);
 }
 
-bool upb_handlerattr_setclosuretype(upb_handlerattr *attr, const void *type) {
-  attr->closure_type_ = type;
-  return true;
-}
-
-const void *upb_handlerattr_closuretype(const upb_handlerattr *attr) {
-  return attr->closure_type_;
-}
-
-bool upb_handlerattr_setreturnclosuretype(upb_handlerattr *attr,
-                                          const void *type) {
-  attr->return_closure_type_ = type;
-  return true;
-}
-
-const void *upb_handlerattr_returnclosuretype(const upb_handlerattr *attr) {
-  return attr->return_closure_type_;
-}
-
-bool upb_handlerattr_setalwaysok(upb_handlerattr *attr, bool alwaysok) {
-  attr->alwaysok_ = alwaysok;
-  return true;
-}
-
-bool upb_handlerattr_alwaysok(const upb_handlerattr *attr) {
-  return attr->alwaysok_;
-}
-
-/* upb_bufhandle **************************************************************/
-
-size_t upb_bufhandle_objofs(const upb_bufhandle *h) {
-  return h->objofs_;
+bool upb_handlercache_addcleanup(upb_handlercache *c, void *p,
+                                 upb_handlerfree *func) {
+  return upb_arena_addcleanup(c->arena, p, func);
 }
 
 /* upb_byteshandler ***********************************************************/
 
-void upb_byteshandler_init(upb_byteshandler* h) {
-  memset(h, 0, sizeof(*h));
-}
-
-/* For when we support handlerfree callbacks. */
-void upb_byteshandler_uninit(upb_byteshandler* h) {
-  UPB_UNUSED(h);
-}
-
 bool upb_byteshandler_setstartstr(upb_byteshandler *h,
                                   upb_startstr_handlerfunc *func, void *d) {
   h->table[UPB_STARTSTR_SELECTOR].func = (upb_func*)func;
-  h->table[UPB_STARTSTR_SELECTOR].attr.handler_data_ = d;
+  h->table[UPB_STARTSTR_SELECTOR].attr.handler_data = d;
   return true;
 }
 
 bool upb_byteshandler_setstring(upb_byteshandler *h,
                                 upb_string_handlerfunc *func, void *d) {
   h->table[UPB_STRING_SELECTOR].func = (upb_func*)func;
-  h->table[UPB_STRING_SELECTOR].attr.handler_data_ = d;
+  h->table[UPB_STRING_SELECTOR].attr.handler_data = d;
   return true;
 }
 
 bool upb_byteshandler_setendstr(upb_byteshandler *h,
                                 upb_endfield_handlerfunc *func, void *d) {
   h->table[UPB_ENDSTR_SELECTOR].func = (upb_func*)func;
-  h->table[UPB_ENDSTR_SELECTOR].attr.handler_data_ = d;
+  h->table[UPB_ENDSTR_SELECTOR].attr.handler_data = d;
   return true;
 }
 
-
 /** Handlers for upb_msg ******************************************************/
 
 typedef struct {
@@ -4635,7 +3772,7 @@
 
 bool upb_msg_setscalarhandler(upb_handlers *h, const upb_fielddef *f,
                               size_t offset, int32_t hasbit) {
-  upb_handlerattr attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr attr = UPB_HANDLERATTR_INIT;
   bool ok;
 
   upb_msg_handlerdata *d = upb_gmalloc(sizeof(*d));
@@ -4643,8 +3780,8 @@
   d->offset = offset;
   d->hasbit = hasbit;
 
-  upb_handlerattr_sethandlerdata(&attr, d);
-  upb_handlerattr_setalwaysok(&attr, true);
+  attr.handler_data = d;
+  attr.alwaysok = true;
   upb_handlers_addcleanup(h, d, upb_gfree);
 
 #define TYPE(u, l) \
@@ -4666,7 +3803,6 @@
   }
 #undef TYPE
 
-  upb_handlerattr_uninit(&attr);
   return ok;
 }
 
@@ -4676,7 +3812,8 @@
                                   size_t *offset,
                                   int32_t *hasbit) {
   const upb_msg_handlerdata *d;
-  upb_func *f = upb_handlers_gethandler(h, s);
+  const void *p;
+  upb_func *f = upb_handlers_gethandler(h, s, &p);
 
   if ((upb_int64_handlerfunc*)f == upb_msg_setint64) {
     *type = UPB_TYPE_INT64;
@@ -4696,12 +3833,13 @@
     return false;
   }
 
-  d = upb_handlers_gethandlerdata(h, s);
+  d = p;
   *offset = d->offset;
   *hasbit = d->hasbit;
   return true;
 }
 
+#include <string.h>
 
 bool upb_fieldtype_mapkeyok(upb_fieldtype_t type) {
   return type == UPB_TYPE_BOOL || type == UPB_TYPE_INT32 ||
@@ -4716,8 +3854,6 @@
 
 /** upb_msgval ****************************************************************/
 
-#define upb_alignof(t) offsetof(struct { char c; t x; }, x)
-
 /* These functions will generate real memcpy() calls on ARM sadly, because
  * the compiler assumes they might not be aligned. */
 
@@ -4752,7 +3888,7 @@
       return sizeof(void*);
     case UPB_TYPE_BYTES:
     case UPB_TYPE_STRING:
-      return sizeof(upb_stringview);
+      return sizeof(upb_strview);
   }
   UPB_UNREACHABLE();
 }
@@ -5242,7 +4378,7 @@
       return sizeof(void*);
     case UPB_TYPE_BYTES:
     case UPB_TYPE_STRING:
-      return sizeof(upb_stringview);
+      return sizeof(upb_strview);
   }
   UPB_UNREACHABLE();
 }
@@ -5406,7 +4542,6 @@
 struct upb_msgfactory {
   const upb_symtab *symtab;  /* We own a ref. */
   upb_inttable layouts;
-  upb_inttable mergehandlers;
 };
 
 upb_msgfactory *upb_msgfactory_new(const upb_symtab *symtab) {
@@ -5414,7 +4549,6 @@
 
   ret->symtab = symtab;
   upb_inttable_init(&ret->layouts, UPB_CTYPE_PTR);
-  upb_inttable_init(&ret->mergehandlers, UPB_CTYPE_CONSTPTR);
 
   return ret;
 }
@@ -5427,14 +4561,7 @@
     upb_msglayout_free(l);
   }
 
-  upb_inttable_begin(&i, &f->mergehandlers);
-  for(; !upb_inttable_done(&i); upb_inttable_next(&i)) {
-    const upb_handlers *h = upb_value_getconstptr(upb_inttable_iter_value(&i));
-    upb_handlers_unref(h, f);
-  }
-
   upb_inttable_uninit(&f->layouts);
-  upb_inttable_uninit(&f->mergehandlers);
   upb_gfree(f);
 }
 
@@ -5464,6 +4591,10 @@
   }
 }
 
+#ifndef UINTPTR_MAX
+#error must include stdint.h first
+#endif
+
 #if UINTPTR_MAX == 0xffffffff
 #define UPB_SIZE(size32, size64) size32
 #else
@@ -5486,864 +4617,13 @@
 #undef UPB_FIELD_AT
 #undef UPB_READ_ONEOF
 #undef UPB_WRITE_ONEOF
-/*
-** upb::RefCounted Implementation
-**
-** Our key invariants are:
-** 1. reference cycles never span groups
-** 2. for ref2(to, from), we increment to's count iff group(from) != group(to)
-**
-** The previous two are how we avoid leaking cycles.  Other important
-** invariants are:
-** 3. for mutable objects "from" and "to", if there exists a ref2(to, from)
-**    this implies group(from) == group(to).  (In practice, what we implement
-**    is even stronger; "from" and "to" will share a group if there has *ever*
-**    been a ref2(to, from), but all that is necessary for correctness is the
-**    weaker one).
-** 4. mutable and immutable objects are never in the same group.
-*/
 
 
-#include <setjmp.h>
-
-static void freeobj(upb_refcounted *o);
-
-const char untracked_val;
-const void *UPB_UNTRACKED_REF = &untracked_val;
-
-/* arch-specific atomic primitives  *******************************************/
-
-#ifdef UPB_THREAD_UNSAFE /*---------------------------------------------------*/
-
-static void atomic_inc(uint32_t *a) { (*a)++; }
-static bool atomic_dec(uint32_t *a) { return --(*a) == 0; }
-
-#elif defined(__GNUC__) || defined(__clang__) /*------------------------------*/
-
-static void atomic_inc(uint32_t *a) { __sync_fetch_and_add(a, 1); }
-static bool atomic_dec(uint32_t *a) { return __sync_sub_and_fetch(a, 1) == 0; }
-
-#elif defined(WIN32) /*-------------------------------------------------------*/
-
-#include <Windows.h>
-
-static void atomic_inc(upb_atomic_t *a) { InterlockedIncrement(&a->val); }
-static bool atomic_dec(upb_atomic_t *a) {
-  return InterlockedDecrement(&a->val) == 0;
-}
-
-#else
-#error Atomic primitives not defined for your platform/CPU.  \
-       Implement them or compile with UPB_THREAD_UNSAFE.
-#endif
-
-/* All static objects point to this refcount.
- * It is special-cased in ref/unref below.  */
-uint32_t static_refcount = -1;
-
-/* We can avoid atomic ops for statically-declared objects.
- * This is a minor optimization but nice since we can avoid degrading under
- * contention in this case. */
-
-static void refgroup(uint32_t *group) {
-  if (group != &static_refcount)
-    atomic_inc(group);
-}
-
-static bool unrefgroup(uint32_t *group) {
-  if (group == &static_refcount) {
-    return false;
-  } else {
-    return atomic_dec(group);
-  }
-}
-
-
-/* Reference tracking (debug only) ********************************************/
-
-#ifdef UPB_DEBUG_REFS
-
-#ifdef UPB_THREAD_UNSAFE
-
-static void upb_lock() {}
-static void upb_unlock() {}
-
-#else
-
-/* User must define functions that lock/unlock a global mutex and link this
- * file against them. */
-void upb_lock();
-void upb_unlock();
-
-#endif
-
-/* UPB_DEBUG_REFS mode counts on being able to malloc() memory in some
- * code-paths that can normally never fail, like upb_refcounted_ref().  Since
- * we have no way to propagage out-of-memory errors back to the user, and since
- * these errors can only occur in UPB_DEBUG_REFS mode, we use an allocator that
- * immediately aborts on failure (avoiding the global allocator, which might
- * inject failures). */
-
-#include <stdlib.h>
-
-static void *upb_debugrefs_allocfunc(upb_alloc *alloc, void *ptr,
-                                     size_t oldsize, size_t size) {
-  UPB_UNUSED(alloc);
-  UPB_UNUSED(oldsize);
-  if (size == 0) {
-    free(ptr);
-    return NULL;
-  } else {
-    void *ret = realloc(ptr, size);
-
-    if (!ret) {
-      abort();
-    }
-
-    return ret;
-  }
-}
-
-upb_alloc upb_alloc_debugrefs = {&upb_debugrefs_allocfunc};
-
-typedef struct {
-  int count;  /* How many refs there are (duplicates only allowed for ref2). */
-  bool is_ref2;
-} trackedref;
-
-static trackedref *trackedref_new(bool is_ref2) {
-  trackedref *ret = upb_malloc(&upb_alloc_debugrefs, sizeof(*ret));
-  ret->count = 1;
-  ret->is_ref2 = is_ref2;
-  return ret;
-}
-
-static void track(const upb_refcounted *r, const void *owner, bool ref2) {
-  upb_value v;
-
-  UPB_ASSERT(owner);
-  if (owner == UPB_UNTRACKED_REF) return;
-
-  upb_lock();
-  if (upb_inttable_lookupptr(r->refs, owner, &v)) {
-    trackedref *ref = upb_value_getptr(v);
-    /* Since we allow multiple ref2's for the same to/from pair without
-     * allocating separate memory for each one, we lose the fine-grained
-     * tracking behavior we get with regular refs.  Since ref2s only happen
-     * inside upb, we'll accept this limitation until/unless there is a really
-     * difficult upb-internal bug that can't be figured out without it. */
-    UPB_ASSERT(ref2);
-    UPB_ASSERT(ref->is_ref2);
-    ref->count++;
-  } else {
-    trackedref *ref = trackedref_new(ref2);
-    upb_inttable_insertptr2(r->refs, owner, upb_value_ptr(ref),
-                            &upb_alloc_debugrefs);
-    if (ref2) {
-      /* We know this cast is safe when it is a ref2, because it's coming from
-       * another refcounted object. */
-      const upb_refcounted *from = owner;
-      UPB_ASSERT(!upb_inttable_lookupptr(from->ref2s, r, NULL));
-      upb_inttable_insertptr2(from->ref2s, r, upb_value_ptr(NULL),
-                              &upb_alloc_debugrefs);
-    }
-  }
-  upb_unlock();
-}
-
-static void untrack(const upb_refcounted *r, const void *owner, bool ref2) {
-  upb_value v;
-  bool found;
-  trackedref *ref;
-
-  UPB_ASSERT(owner);
-  if (owner == UPB_UNTRACKED_REF) return;
-
-  upb_lock();
-  found = upb_inttable_lookupptr(r->refs, owner, &v);
-  /* This assert will fail if an owner attempts to release a ref it didn't have. */
-  UPB_ASSERT(found);
-  ref = upb_value_getptr(v);
-  UPB_ASSERT(ref->is_ref2 == ref2);
-  if (--ref->count == 0) {
-    free(ref);
-    upb_inttable_removeptr(r->refs, owner, NULL);
-    if (ref2) {
-      /* We know this cast is safe when it is a ref2, because it's coming from
-       * another refcounted object. */
-      const upb_refcounted *from = owner;
-      bool removed = upb_inttable_removeptr(from->ref2s, r, NULL);
-      UPB_ASSERT(removed);
-    }
-  }
-  upb_unlock();
-}
-
-static void checkref(const upb_refcounted *r, const void *owner, bool ref2) {
-  upb_value v;
-  bool found;
-  trackedref *ref;
-
-  upb_lock();
-  found = upb_inttable_lookupptr(r->refs, owner, &v);
-  UPB_ASSERT(found);
-  ref = upb_value_getptr(v);
-  UPB_ASSERT(ref->is_ref2 == ref2);
-  upb_unlock();
-}
-
-/* Populates the given UPB_CTYPE_INT32 inttable with counts of ref2's that
- * originate from the given owner. */
-static void getref2s(const upb_refcounted *owner, upb_inttable *tab) {
-  upb_inttable_iter i;
-
-  upb_lock();
-  upb_inttable_begin(&i, owner->ref2s);
-  for(; !upb_inttable_done(&i); upb_inttable_next(&i)) {
-    upb_value v;
-    upb_value count;
-    trackedref *ref;
-    bool found;
-
-    upb_refcounted *to = (upb_refcounted*)upb_inttable_iter_key(&i);
-
-    /* To get the count we need to look in the target's table. */
-    found = upb_inttable_lookupptr(to->refs, owner, &v);
-    UPB_ASSERT(found);
-    ref = upb_value_getptr(v);
-    count = upb_value_int32(ref->count);
-
-    upb_inttable_insertptr2(tab, to, count, &upb_alloc_debugrefs);
-  }
-  upb_unlock();
-}
-
-typedef struct {
-  upb_inttable ref2;
-  const upb_refcounted *obj;
-} check_state;
-
-static void visit_check(const upb_refcounted *obj, const upb_refcounted *subobj,
-                        void *closure) {
-  check_state *s = closure;
-  upb_inttable *ref2 = &s->ref2;
-  upb_value v;
-  bool removed;
-  int32_t newcount;
-
-  UPB_ASSERT(obj == s->obj);
-  UPB_ASSERT(subobj);
-  removed = upb_inttable_removeptr(ref2, subobj, &v);
-  /* The following assertion will fail if the visit() function visits a subobj
-   * that it did not have a ref2 on, or visits the same subobj too many times. */
-  UPB_ASSERT(removed);
-  newcount = upb_value_getint32(v) - 1;
-  if (newcount > 0) {
-    upb_inttable_insert2(ref2, (uintptr_t)subobj, upb_value_int32(newcount),
-                         &upb_alloc_debugrefs);
-  }
-}
-
-static void visit(const upb_refcounted *r, upb_refcounted_visit *v,
-                  void *closure) {
-  /* In DEBUG_REFS mode we know what existing ref2 refs there are, so we know
-   * exactly the set of nodes that visit() should visit.  So we verify visit()'s
-   * correctness here. */
-  check_state state;
-  state.obj = r;
-  upb_inttable_init2(&state.ref2, UPB_CTYPE_INT32, &upb_alloc_debugrefs);
-  getref2s(r, &state.ref2);
-
-  /* This should visit any children in the ref2 table. */
-  if (r->vtbl->visit) r->vtbl->visit(r, visit_check, &state);
-
-  /* This assertion will fail if the visit() function missed any children. */
-  UPB_ASSERT(upb_inttable_count(&state.ref2) == 0);
-  upb_inttable_uninit2(&state.ref2, &upb_alloc_debugrefs);
-  if (r->vtbl->visit) r->vtbl->visit(r, v, closure);
-}
-
-static void trackinit(upb_refcounted *r) {
-  r->refs = upb_malloc(&upb_alloc_debugrefs, sizeof(*r->refs));
-  r->ref2s = upb_malloc(&upb_alloc_debugrefs, sizeof(*r->ref2s));
-  upb_inttable_init2(r->refs, UPB_CTYPE_PTR, &upb_alloc_debugrefs);
-  upb_inttable_init2(r->ref2s, UPB_CTYPE_PTR, &upb_alloc_debugrefs);
-}
-
-static void trackfree(const upb_refcounted *r) {
-  upb_inttable_uninit2(r->refs, &upb_alloc_debugrefs);
-  upb_inttable_uninit2(r->ref2s, &upb_alloc_debugrefs);
-  upb_free(&upb_alloc_debugrefs, r->refs);
-  upb_free(&upb_alloc_debugrefs, r->ref2s);
-}
-
-#else
-
-static void track(const upb_refcounted *r, const void *owner, bool ref2) {
-  UPB_UNUSED(r);
-  UPB_UNUSED(owner);
-  UPB_UNUSED(ref2);
-}
-
-static void untrack(const upb_refcounted *r, const void *owner, bool ref2) {
-  UPB_UNUSED(r);
-  UPB_UNUSED(owner);
-  UPB_UNUSED(ref2);
-}
-
-static void checkref(const upb_refcounted *r, const void *owner, bool ref2) {
-  UPB_UNUSED(r);
-  UPB_UNUSED(owner);
-  UPB_UNUSED(ref2);
-}
-
-static void trackinit(upb_refcounted *r) {
-  UPB_UNUSED(r);
-}
-
-static void trackfree(const upb_refcounted *r) {
-  UPB_UNUSED(r);
-}
-
-static void visit(const upb_refcounted *r, upb_refcounted_visit *v,
-                  void *closure) {
-  if (r->vtbl->visit) r->vtbl->visit(r, v, closure);
-}
-
-#endif  /* UPB_DEBUG_REFS */
-
-
-/* freeze() *******************************************************************/
-
-/* The freeze() operation is by far the most complicated part of this scheme.
- * We compute strongly-connected components and then mutate the graph such that
- * we preserve the invariants documented at the top of this file.  And we must
- * handle out-of-memory errors gracefully (without leaving the graph
- * inconsistent), which adds to the fun. */
-
-/* The state used by the freeze operation (shared across many functions). */
-typedef struct {
-  int depth;
-  int maxdepth;
-  uint64_t index;
-  /* Maps upb_refcounted* -> attributes (color, etc).  attr layout varies by
-   * color. */
-  upb_inttable objattr;
-  upb_inttable stack;   /* stack of upb_refcounted* for Tarjan's algorithm. */
-  upb_inttable groups;  /* array of uint32_t*, malloc'd refcounts for new groups */
-  upb_status *status;
-  jmp_buf err;
-} tarjan;
-
-static void release_ref2(const upb_refcounted *obj,
-                         const upb_refcounted *subobj,
-                         void *closure);
-
-/* Node attributes -----------------------------------------------------------*/
-
-/* After our analysis phase all nodes will be either GRAY or WHITE. */
-
-typedef enum {
-  BLACK = 0,  /* Object has not been seen. */
-  GRAY,   /* Object has been found via a refgroup but may not be reachable. */
-  GREEN,  /* Object is reachable and is currently on the Tarjan stack. */
-  WHITE   /* Object is reachable and has been assigned a group (SCC). */
-} color_t;
-
-UPB_NORETURN static void err(tarjan *t) { longjmp(t->err, 1); }
-UPB_NORETURN static void oom(tarjan *t) {
-  upb_status_seterrmsg(t->status, "out of memory");
-  err(t);
-}
-
-static uint64_t trygetattr(const tarjan *t, const upb_refcounted *r) {
-  upb_value v;
-  return upb_inttable_lookupptr(&t->objattr, r, &v) ?
-      upb_value_getuint64(v) : 0;
-}
-
-static uint64_t getattr(const tarjan *t, const upb_refcounted *r) {
-  upb_value v;
-  bool found = upb_inttable_lookupptr(&t->objattr, r, &v);
-  UPB_ASSERT(found);
-  return upb_value_getuint64(v);
-}
-
-static void setattr(tarjan *t, const upb_refcounted *r, uint64_t attr) {
-  upb_inttable_removeptr(&t->objattr, r, NULL);
-  upb_inttable_insertptr(&t->objattr, r, upb_value_uint64(attr));
-}
-
-static color_t color(tarjan *t, const upb_refcounted *r) {
-  return trygetattr(t, r) & 0x3;  /* Color is always stored in the low 2 bits. */
-}
-
-static void set_gray(tarjan *t, const upb_refcounted *r) {
-  UPB_ASSERT(color(t, r) == BLACK);
-  setattr(t, r, GRAY);
-}
-
-/* Pushes an obj onto the Tarjan stack and sets it to GREEN. */
-static void push(tarjan *t, const upb_refcounted *r) {
-  UPB_ASSERT(color(t, r) == BLACK || color(t, r) == GRAY);
-  /* This defines the attr layout for the GREEN state.  "index" and "lowlink"
-   * get 31 bits, which is plenty (limit of 2B objects frozen at a time). */
-  setattr(t, r, GREEN | (t->index << 2) | (t->index << 33));
-  if (++t->index == 0x80000000) {
-    upb_status_seterrmsg(t->status, "too many objects to freeze");
-    err(t);
-  }
-  upb_inttable_push(&t->stack, upb_value_ptr((void*)r));
-}
-
-/* Pops an obj from the Tarjan stack and sets it to WHITE, with a ptr to its
- * SCC group. */
-static upb_refcounted *pop(tarjan *t) {
-  upb_refcounted *r = upb_value_getptr(upb_inttable_pop(&t->stack));
-  UPB_ASSERT(color(t, r) == GREEN);
-  /* This defines the attr layout for nodes in the WHITE state.
-   * Top of group stack is [group, NULL]; we point at group. */
-  setattr(t, r, WHITE | (upb_inttable_count(&t->groups) - 2) << 8);
-  return r;
-}
-
-static void tarjan_newgroup(tarjan *t) {
-  uint32_t *group = upb_gmalloc(sizeof(*group));
-  if (!group) oom(t);
-  /* Push group and empty group leader (we'll fill in leader later). */
-  if (!upb_inttable_push(&t->groups, upb_value_ptr(group)) ||
-      !upb_inttable_push(&t->groups, upb_value_ptr(NULL))) {
-    upb_gfree(group);
-    oom(t);
-  }
-  *group = 0;
-}
-
-static uint32_t idx(tarjan *t, const upb_refcounted *r) {
-  UPB_ASSERT(color(t, r) == GREEN);
-  return (getattr(t, r) >> 2) & 0x7FFFFFFF;
-}
-
-static uint32_t lowlink(tarjan *t, const upb_refcounted *r) {
-  if (color(t, r) == GREEN) {
-    return getattr(t, r) >> 33;
-  } else {
-    return UINT32_MAX;
-  }
-}
-
-static void set_lowlink(tarjan *t, const upb_refcounted *r, uint32_t lowlink) {
-  UPB_ASSERT(color(t, r) == GREEN);
-  setattr(t, r, ((uint64_t)lowlink << 33) | (getattr(t, r) & 0x1FFFFFFFF));
-}
-
-static uint32_t *group(tarjan *t, upb_refcounted *r) {
-  uint64_t groupnum;
-  upb_value v;
-  bool found;
-
-  UPB_ASSERT(color(t, r) == WHITE);
-  groupnum = getattr(t, r) >> 8;
-  found = upb_inttable_lookup(&t->groups, groupnum, &v);
-  UPB_ASSERT(found);
-  return upb_value_getptr(v);
-}
-
-/* If the group leader for this object's group has not previously been set,
- * the given object is assigned to be its leader. */
-static upb_refcounted *groupleader(tarjan *t, upb_refcounted *r) {
-  uint64_t leader_slot;
-  upb_value v;
-  bool found;
-
-  UPB_ASSERT(color(t, r) == WHITE);
-  leader_slot = (getattr(t, r) >> 8) + 1;
-  found = upb_inttable_lookup(&t->groups, leader_slot, &v);
-  UPB_ASSERT(found);
-  if (upb_value_getptr(v)) {
-    return upb_value_getptr(v);
-  } else {
-    upb_inttable_remove(&t->groups, leader_slot, NULL);
-    upb_inttable_insert(&t->groups, leader_slot, upb_value_ptr(r));
-    return r;
-  }
-}
-
-
-/* Tarjan's algorithm --------------------------------------------------------*/
-
-/* See:
- *   http://en.wikipedia.org/wiki/Tarjan%27s_strongly_connected_components_algorithm */
-static void do_tarjan(const upb_refcounted *obj, tarjan *t);
-
-static void tarjan_visit(const upb_refcounted *obj,
-                         const upb_refcounted *subobj,
-                         void *closure) {
-  tarjan *t = closure;
-  if (++t->depth > t->maxdepth) {
-    upb_status_seterrf(t->status, "graph too deep to freeze (%d)", t->maxdepth);
-    err(t);
-  } else if (subobj->is_frozen || color(t, subobj) == WHITE) {
-    /* Do nothing: we don't want to visit or color already-frozen nodes,
-     * and WHITE nodes have already been assigned a SCC. */
-  } else if (color(t, subobj) < GREEN) {
-    /* Subdef has not yet been visited; recurse on it. */
-    do_tarjan(subobj, t);
-    set_lowlink(t, obj, UPB_MIN(lowlink(t, obj), lowlink(t, subobj)));
-  } else if (color(t, subobj) == GREEN) {
-    /* Subdef is in the stack and hence in the current SCC. */
-    set_lowlink(t, obj, UPB_MIN(lowlink(t, obj), idx(t, subobj)));
-  }
-  --t->depth;
-}
-
-static void do_tarjan(const upb_refcounted *obj, tarjan *t) {
-  if (color(t, obj) == BLACK) {
-    /* We haven't seen this object's group; mark the whole group GRAY. */
-    const upb_refcounted *o = obj;
-    do { set_gray(t, o); } while ((o = o->next) != obj);
-  }
-
-  push(t, obj);
-  visit(obj, tarjan_visit, t);
-  if (lowlink(t, obj) == idx(t, obj)) {
-    tarjan_newgroup(t);
-    while (pop(t) != obj)
-      ;
-  }
-}
-
-
-/* freeze() ------------------------------------------------------------------*/
-
-static void crossref(const upb_refcounted *r, const upb_refcounted *subobj,
-                     void *_t) {
-  tarjan *t = _t;
-  UPB_ASSERT(color(t, r) > BLACK);
-  if (color(t, subobj) > BLACK && r->group != subobj->group) {
-    /* Previously this ref was not reflected in subobj->group because they
-     * were in the same group; now that they are split a ref must be taken. */
-    refgroup(subobj->group);
-  }
-}
-
-static bool freeze(upb_refcounted *const*roots, int n, upb_status *s,
-                   int maxdepth) {
-  volatile bool ret = false;
-  int i;
-  upb_inttable_iter iter;
-
-  /* We run in two passes so that we can allocate all memory before performing
-   * any mutation of the input -- this allows us to leave the input unchanged
-   * in the case of memory allocation failure. */
-  tarjan t;
-  t.index = 0;
-  t.depth = 0;
-  t.maxdepth = maxdepth;
-  t.status = s;
-  if (!upb_inttable_init(&t.objattr, UPB_CTYPE_UINT64)) goto err1;
-  if (!upb_inttable_init(&t.stack, UPB_CTYPE_PTR)) goto err2;
-  if (!upb_inttable_init(&t.groups, UPB_CTYPE_PTR)) goto err3;
-  if (setjmp(t.err) != 0) goto err4;
-
-
-  for (i = 0; i < n; i++) {
-    if (color(&t, roots[i]) < GREEN) {
-      do_tarjan(roots[i], &t);
-    }
-  }
-
-  /* If we've made it this far, no further errors are possible so it's safe to
-   * mutate the objects without risk of leaving them in an inconsistent state. */
-  ret = true;
-
-  /* The transformation that follows requires care.  The preconditions are:
-   * - all objects in attr map are WHITE or GRAY, and are in mutable groups
-   *   (groups of all mutable objs)
-   * - no ref2(to, from) refs have incremented count(to) if both "to" and
-   *   "from" are in our attr map (this follows from invariants (2) and (3)) */
-
-  /* Pass 1: we remove WHITE objects from their mutable groups, and add them to
-   * new groups  according to the SCC's we computed.  These new groups will
-   * consist of only frozen objects.  None will be immediately collectible,
-   * because WHITE objects are by definition reachable from one of "roots",
-   * which the caller must own refs on. */
-  upb_inttable_begin(&iter, &t.objattr);
-  for(; !upb_inttable_done(&iter); upb_inttable_next(&iter)) {
-    upb_refcounted *obj = (upb_refcounted*)upb_inttable_iter_key(&iter);
-    /* Since removal from a singly-linked list requires access to the object's
-     * predecessor, we consider obj->next instead of obj for moving.  With the
-     * while() loop we guarantee that we will visit every node's predecessor.
-     * Proof:
-     *  1. every node's predecessor is in our attr map.
-     *  2. though the loop body may change a node's predecessor, it will only
-     *     change it to be the node we are currently operating on, so with a
-     *     while() loop we guarantee ourselves the chance to remove each node. */
-    while (color(&t, obj->next) == WHITE &&
-           group(&t, obj->next) != obj->next->group) {
-      upb_refcounted *leader;
-
-      /* Remove from old group. */
-      upb_refcounted *move = obj->next;
-      if (obj == move) {
-        /* Removing the last object from a group. */
-        UPB_ASSERT(*obj->group == obj->individual_count);
-        upb_gfree(obj->group);
-      } else {
-        obj->next = move->next;
-        /* This may decrease to zero; we'll collect GRAY objects (if any) that
-         * remain in the group in the third pass. */
-        UPB_ASSERT(*move->group >= move->individual_count);
-        *move->group -= move->individual_count;
-      }
-
-      /* Add to new group. */
-      leader = groupleader(&t, move);
-      if (move == leader) {
-        /* First object added to new group is its leader. */
-        move->group = group(&t, move);
-        move->next = move;
-        *move->group = move->individual_count;
-      } else {
-        /* Group already has at least one object in it. */
-        UPB_ASSERT(leader->group == group(&t, move));
-        move->group = group(&t, move);
-        move->next = leader->next;
-        leader->next = move;
-        *move->group += move->individual_count;
-      }
-
-      move->is_frozen = true;
-    }
-  }
-
-  /* Pass 2: GRAY and WHITE objects "obj" with ref2(to, obj) references must
-   * increment count(to) if group(obj) != group(to) (which could now be the
-   * case if "to" was just frozen). */
-  upb_inttable_begin(&iter, &t.objattr);
-  for(; !upb_inttable_done(&iter); upb_inttable_next(&iter)) {
-    upb_refcounted *obj = (upb_refcounted*)upb_inttable_iter_key(&iter);
-    visit(obj, crossref, &t);
-  }
-
-  /* Pass 3: GRAY objects are collected if their group's refcount dropped to
-   * zero when we removed its white nodes.  This can happen if they had only
-   * been kept alive by virtue of sharing a group with an object that was just
-   * frozen.
-   *
-   * It is important that we do this last, since the GRAY object's free()
-   * function could call unref2() on just-frozen objects, which will decrement
-   * refs that were added in pass 2. */
-  upb_inttable_begin(&iter, &t.objattr);
-  for(; !upb_inttable_done(&iter); upb_inttable_next(&iter)) {
-    upb_refcounted *obj = (upb_refcounted*)upb_inttable_iter_key(&iter);
-    if (obj->group == NULL || *obj->group == 0) {
-      if (obj->group) {
-        upb_refcounted *o;
-
-        /* We eagerly free() the group's count (since we can't easily determine
-         * the group's remaining size it's the easiest way to ensure it gets
-         * done). */
-        upb_gfree(obj->group);
-
-        /* Visit to release ref2's (done in a separate pass since release_ref2
-         * depends on o->group being unmodified so it can test merged()). */
-        o = obj;
-        do { visit(o, release_ref2, NULL); } while ((o = o->next) != obj);
-
-        /* Mark "group" fields as NULL so we know to free the objects later in
-         * this loop, but also don't try to delete the group twice. */
-        o = obj;
-        do { o->group = NULL; } while ((o = o->next) != obj);
-      }
-      freeobj(obj);
-    }
-  }
-
-err4:
-  if (!ret) {
-    upb_inttable_begin(&iter, &t.groups);
-    for(; !upb_inttable_done(&iter); upb_inttable_next(&iter))
-      upb_gfree(upb_value_getptr(upb_inttable_iter_value(&iter)));
-  }
-  upb_inttable_uninit(&t.groups);
-err3:
-  upb_inttable_uninit(&t.stack);
-err2:
-  upb_inttable_uninit(&t.objattr);
-err1:
-  return ret;
-}
-
-
-/* Misc internal functions  ***************************************************/
-
-static bool merged(const upb_refcounted *r, const upb_refcounted *r2) {
-  return r->group == r2->group;
-}
-
-static void merge(upb_refcounted *r, upb_refcounted *from) {
-  upb_refcounted *base;
-  upb_refcounted *tmp;
-
-  if (merged(r, from)) return;
-  *r->group += *from->group;
-  upb_gfree(from->group);
-  base = from;
-
-  /* Set all refcount pointers in the "from" chain to the merged refcount.
-   *
-   * TODO(haberman): this linear algorithm can result in an overall O(n^2) bound
-   * if the user continuously extends a group by one object.  Prevent this by
-   * using one of the techniques in this paper:
-   *     http://bioinfo.ict.ac.cn/~dbu/AlgorithmCourses/Lectures/Union-Find-Tarjan.pdf */
-  do { from->group = r->group; } while ((from = from->next) != base);
-
-  /* Merge the two circularly linked lists by swapping their next pointers. */
-  tmp = r->next;
-  r->next = base->next;
-  base->next = tmp;
-}
-
-static void unref(const upb_refcounted *r);
-
-static void release_ref2(const upb_refcounted *obj,
-                         const upb_refcounted *subobj,
-                         void *closure) {
-  UPB_UNUSED(closure);
-  untrack(subobj, obj, true);
-  if (!merged(obj, subobj)) {
-    UPB_ASSERT(subobj->is_frozen);
-    unref(subobj);
-  }
-}
-
-static void unref(const upb_refcounted *r) {
-  if (unrefgroup(r->group)) {
-    const upb_refcounted *o;
-
-    upb_gfree(r->group);
-
-    /* In two passes, since release_ref2 needs a guarantee that any subobjs
-     * are alive. */
-    o = r;
-    do { visit(o, release_ref2, NULL); } while((o = o->next) != r);
-
-    o = r;
-    do {
-      const upb_refcounted *next = o->next;
-      UPB_ASSERT(o->is_frozen || o->individual_count == 0);
-      freeobj((upb_refcounted*)o);
-      o = next;
-    } while(o != r);
-  }
-}
-
-static void freeobj(upb_refcounted *o) {
-  trackfree(o);
-  o->vtbl->free((upb_refcounted*)o);
-}
-
-
-/* Public interface ***********************************************************/
-
-bool upb_refcounted_init(upb_refcounted *r,
-                         const struct upb_refcounted_vtbl *vtbl,
-                         const void *owner) {
-#ifndef NDEBUG
-  /* Endianness check.  This is unrelated to upb_refcounted, it's just a
-   * convenient place to put the check that we can be assured will run for
-   * basically every program using upb. */
-  const int x = 1;
-#ifdef UPB_BIG_ENDIAN
-  UPB_ASSERT(*(char*)&x != 1);
-#else
-  UPB_ASSERT(*(char*)&x == 1);
-#endif
-#endif
-
-  r->next = r;
-  r->vtbl = vtbl;
-  r->individual_count = 0;
-  r->is_frozen = false;
-  r->group = upb_gmalloc(sizeof(*r->group));
-  if (!r->group) return false;
-  *r->group = 0;
-  trackinit(r);
-  upb_refcounted_ref(r, owner);
-  return true;
-}
-
-bool upb_refcounted_isfrozen(const upb_refcounted *r) {
-  return r->is_frozen;
-}
-
-void upb_refcounted_ref(const upb_refcounted *r, const void *owner) {
-  track(r, owner, false);
-  if (!r->is_frozen)
-    ((upb_refcounted*)r)->individual_count++;
-  refgroup(r->group);
-}
-
-void upb_refcounted_unref(const upb_refcounted *r, const void *owner) {
-  untrack(r, owner, false);
-  if (!r->is_frozen)
-    ((upb_refcounted*)r)->individual_count--;
-  unref(r);
-}
-
-void upb_refcounted_ref2(const upb_refcounted *r, upb_refcounted *from) {
-  UPB_ASSERT(!from->is_frozen);  /* Non-const pointer implies this. */
-  track(r, from, true);
-  if (r->is_frozen) {
-    refgroup(r->group);
-  } else {
-    merge((upb_refcounted*)r, from);
-  }
-}
-
-void upb_refcounted_unref2(const upb_refcounted *r, upb_refcounted *from) {
-  UPB_ASSERT(!from->is_frozen);  /* Non-const pointer implies this. */
-  untrack(r, from, true);
-  if (r->is_frozen) {
-    unref(r);
-  } else {
-    UPB_ASSERT(merged(r, from));
-  }
-}
-
-void upb_refcounted_donateref(
-    const upb_refcounted *r, const void *from, const void *to) {
-  UPB_ASSERT(from != to);
-  if (to != NULL)
-    upb_refcounted_ref(r, to);
-  if (from != NULL)
-    upb_refcounted_unref(r, from);
-}
-
-void upb_refcounted_checkref(const upb_refcounted *r, const void *owner) {
-  checkref(r, owner, false);
-}
-
-bool upb_refcounted_freeze(upb_refcounted *const*roots, int n, upb_status *s,
-                           int maxdepth) {
-  int i;
-  bool ret;
-  for (i = 0; i < n; i++) {
-    UPB_ASSERT(!roots[i]->is_frozen);
-  }
-  ret = freeze(roots, n, s, maxdepth);
-  UPB_ASSERT(!s || ret == upb_ok(s));
-  return ret;
-}
-
-
-bool upb_bufsrc_putbuf(const char *buf, size_t len, upb_bytessink *sink) {
+bool upb_bufsrc_putbuf(const char *buf, size_t len, upb_bytessink sink) {
   void *subc;
   bool ret;
-  upb_bufhandle handle;
-  upb_bufhandle_init(&handle);
-  upb_bufhandle_setbuf(&handle, buf, 0);
+  upb_bufhandle handle = UPB_BUFHANDLE_INIT;
+  handle.buf = buf;
   ret = upb_bytessink_start(sink, len, &subc);
   if (ret && len != 0) {
     ret = (upb_bytessink_putbuf(sink, subc, buf, len, &handle) >= len);
@@ -6351,79 +4631,8 @@
   if (ret) {
     ret = upb_bytessink_end(sink);
   }
-  upb_bufhandle_uninit(&handle);
   return ret;
 }
-
-struct upb_bufsink {
-  upb_byteshandler handler;
-  upb_bytessink sink;
-  upb_env *env;
-  char *ptr;
-  size_t len, size;
-};
-
-static void *upb_bufsink_start(void *_sink, const void *hd, size_t size_hint) {
-  upb_bufsink *sink = _sink;
-  UPB_UNUSED(hd);
-  UPB_UNUSED(size_hint);
-  sink->len = 0;
-  return sink;
-}
-
-static size_t upb_bufsink_string(void *_sink, const void *hd, const char *ptr,
-                                size_t len, const upb_bufhandle *handle) {
-  upb_bufsink *sink = _sink;
-  size_t new_size = sink->size;
-
-  UPB_ASSERT(new_size > 0);
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-
-  while (sink->len + len > new_size) {
-    new_size *= 2;
-  }
-
-  if (new_size != sink->size) {
-    sink->ptr = upb_env_realloc(sink->env, sink->ptr, sink->size, new_size);
-    sink->size = new_size;
-  }
-
-  memcpy(sink->ptr + sink->len, ptr, len);
-  sink->len += len;
-
-  return len;
-}
-
-upb_bufsink *upb_bufsink_new(upb_env *env) {
-  upb_bufsink *sink = upb_env_malloc(env, sizeof(upb_bufsink));
-  upb_byteshandler_init(&sink->handler);
-  upb_byteshandler_setstartstr(&sink->handler, upb_bufsink_start, NULL);
-  upb_byteshandler_setstring(&sink->handler, upb_bufsink_string, NULL);
-
-  upb_bytessink_reset(&sink->sink, &sink->handler, sink);
-
-  sink->env = env;
-  sink->size = 32;
-  sink->ptr = upb_env_malloc(env, sink->size);
-  sink->len = 0;
-
-  return sink;
-}
-
-void upb_bufsink_free(upb_bufsink *sink) {
-  upb_env_free(sink->env, sink->ptr);
-  upb_env_free(sink->env, sink);
-}
-
-upb_bytessink *upb_bufsink_sink(upb_bufsink *sink) {
-  return &sink->sink;
-}
-
-const char *upb_bufsink_getdata(const upb_bufsink *sink, size_t *len) {
-  *len = sink->len;
-  return sink->ptr;
-}
 /*
 ** upb_table Implementation
 **
@@ -6806,6 +5015,7 @@
 }
 
 bool upb_strtable_done(const upb_strtable_iter *i) {
+  if (!i->t) return true;
   return i->index >= upb_table_size(&i->t->t) ||
          upb_tabent_isempty(str_tabent(i));
 }
@@ -6828,6 +5038,7 @@
 }
 
 void upb_strtable_iter_setdone(upb_strtable_iter *i) {
+  i->t = NULL;
   i->index = SIZE_MAX;
 }
 
@@ -7117,6 +5328,7 @@
 }
 
 bool upb_inttable_done(const upb_inttable_iter *i) {
+  if (!i->t) return true;
   if (i->array_part) {
     return i->index >= i->t->array_size ||
            !upb_arrhas(int_arrent(i));
@@ -7139,6 +5351,7 @@
 }
 
 void upb_inttable_iter_setdone(upb_inttable_iter *i) {
+  i->t = NULL;
   i->index = SIZE_MAX;
   i->array_part = false;
 }
@@ -7337,12 +5550,6 @@
 #include <stdlib.h>
 #include <string.h>
 
-bool upb_dumptostderr(void *closure, const upb_status* status) {
-  UPB_UNUSED(closure);
-  fprintf(stderr, "%s\n", upb_status_errmsg(status));
-  return false;
-}
-
 /* Guarantee null-termination and provide ellipsis truncation.
  * It may be tempting to "optimize" this by initializing these final
  * four bytes up-front and then being careful never to overwrite them,
@@ -7354,39 +5561,21 @@
   memcpy(status->msg + sizeof(status->msg) - len, ellipsis, len);
 }
 
-
-/* upb_upberr *****************************************************************/
-
-upb_errorspace upb_upberr = {"upb error"};
-
-void upb_upberr_setoom(upb_status *status) {
-  status->error_space_ = &upb_upberr;
-  upb_status_seterrmsg(status, "Out of memory");
-}
-
-
 /* upb_status *****************************************************************/
 
 void upb_status_clear(upb_status *status) {
   if (!status) return;
-  status->ok_ = true;
-  status->code_ = 0;
+  status->ok = true;
   status->msg[0] = '\0';
 }
 
-bool upb_ok(const upb_status *status) { return status->ok_; }
-
-upb_errorspace *upb_status_errspace(const upb_status *status) {
-  return status->error_space_;
-}
-
-int upb_status_errcode(const upb_status *status) { return status->code_; }
+bool upb_ok(const upb_status *status) { return status->ok; }
 
 const char *upb_status_errmsg(const upb_status *status) { return status->msg; }
 
 void upb_status_seterrmsg(upb_status *status, const char *msg) {
   if (!status) return;
-  status->ok_ = false;
+  status->ok = false;
   strncpy(status->msg, msg, sizeof(status->msg));
   nullz(status);
 }
@@ -7400,17 +5589,11 @@
 
 void upb_status_vseterrf(upb_status *status, const char *fmt, va_list args) {
   if (!status) return;
-  status->ok_ = false;
+  status->ok = false;
   _upb_vsnprintf(status->msg, sizeof(status->msg), fmt, args);
   nullz(status);
 }
 
-void upb_status_copy(upb_status *to, const upb_status *from) {
-  if (!to) return;
-  *to = *from;
-}
-
-
 /* upb_alloc ******************************************************************/
 
 static void *upb_global_allocfunc(upb_alloc *alloc, void *ptr, size_t oldsize,
@@ -7427,7 +5610,6 @@
 
 upb_alloc upb_alloc_global = {&upb_global_allocfunc};
 
-
 /* upb_arena ******************************************************************/
 
 /* Be conservative and choose 16 in case anyone is using SSE. */
@@ -7437,6 +5619,26 @@
   return ((size + maxalign - 1) / maxalign) * maxalign;
 }
 
+struct upb_arena {
+  /* We implement the allocator interface.
+   * This must be the first member of upb_arena! */
+  upb_alloc alloc;
+
+  /* Allocator to allocate arena blocks.  We are responsible for freeing these
+   * when we are destroyed. */
+  upb_alloc *block_alloc;
+
+  size_t bytes_allocated;
+  size_t next_block_size;
+  size_t max_block_size;
+
+  /* Linked list of blocks.  Points to an arena_block, defined in env.c */
+  void *block_head;
+
+  /* Cleanup entries.  Pointer to a cleanup_ent, defined in env.c */
+  void *cleanup_head;
+};
+
 typedef struct mem_block {
   struct mem_block *next;
   size_t size;
@@ -7465,7 +5667,6 @@
   /* TODO(haberman): ASAN poison. */
 }
 
-
 static mem_block *upb_arena_allocblock(upb_arena *a, size_t size) {
   size_t block_size = UPB_MAX(size, a->next_block_size) + sizeof(mem_block);
   mem_block *block = upb_malloc(a->block_alloc, block_size);
@@ -7518,7 +5719,29 @@
 
 /* Public Arena API ***********************************************************/
 
-void upb_arena_init(upb_arena *a) {
+#define upb_alignof(type) offsetof (struct { char c; type member; }, member)
+
+upb_arena *upb_arena_init(void *mem, size_t n, upb_alloc *alloc) {
+  const size_t first_block_overhead = sizeof(upb_arena) + sizeof(mem_block);
+  upb_arena *a;
+  bool owned = false;
+
+  /* Round block size down to alignof(*a) since we will allocate the arena
+   * itself at the end. */
+  n &= ~(upb_alignof(upb_arena) - 1);
+
+  if (n < first_block_overhead) {
+    /* We need to malloc the initial block. */
+    n = first_block_overhead + 256;
+    owned = true;
+    if (!alloc || !(mem = upb_malloc(alloc, n))) {
+      return NULL;
+    }
+  }
+
+  a = (void*)((char*)mem + n - sizeof(*a));
+  n -= sizeof(*a);
+
   a->alloc.func = &upb_arena_doalloc;
   a->block_alloc = &upb_alloc_global;
   a->bytes_allocated = 0;
@@ -7526,21 +5749,16 @@
   a->max_block_size = 16384;
   a->cleanup_head = NULL;
   a->block_head = NULL;
+  a->block_alloc = alloc;
+
+  upb_arena_addblock(a, mem, n, owned);
+
+  return a;
 }
 
-void upb_arena_init2(upb_arena *a, void *mem, size_t size, upb_alloc *alloc) {
-  upb_arena_init(a);
+#undef upb_alignof
 
-  if (size > sizeof(mem_block)) {
-    upb_arena_addblock(a, mem, size, false);
-  }
-
-  if (alloc) {
-    a->block_alloc = alloc;
-  }
-}
-
-void upb_arena_uninit(upb_arena *a) {
+void upb_arena_free(upb_arena *a) {
   cleanup_ent *ent = a->cleanup_head;
   mem_block *block = a->block_head;
 
@@ -7552,6 +5770,7 @@
   /* Must do this after running cleanup functions, because this will delete
    * the memory we store our cleanup entries in! */
   while (block) {
+    /* Load first since we are deleting block. */
     mem_block *next = block->next;
 
     if (block->owned) {
@@ -7560,13 +5779,9 @@
 
     block = next;
   }
-
-  /* Protect against multiple-uninit. */
-  a->cleanup_head = NULL;
-  a->block_head = NULL;
 }
 
-bool upb_arena_addcleanup(upb_arena *a, upb_cleanup_func *func, void *ud) {
+bool upb_arena_addcleanup(upb_arena *a, void *ud, upb_cleanup_func *func) {
   cleanup_ent *ent = upb_malloc(&a->alloc, sizeof(cleanup_ent));
   if (!ent) {
     return false;  /* Out of memory. */
@@ -7583,1912 +5798,12 @@
 size_t upb_arena_bytesallocated(const upb_arena *a) {
   return a->bytes_allocated;
 }
-
-
-/* Standard error functions ***************************************************/
-
-static bool default_err(void *ud, const upb_status *status) {
-  UPB_UNUSED(ud);
-  UPB_UNUSED(status);
-  return false;
-}
-
-static bool write_err_to(void *ud, const upb_status *status) {
-  upb_status *copy_to = ud;
-  upb_status_copy(copy_to, status);
-  return false;
-}
-
-
-/* upb_env ********************************************************************/
-
-void upb_env_initonly(upb_env *e) {
-  e->ok_ = true;
-  e->error_func_ = &default_err;
-  e->error_ud_ = NULL;
-}
-
-void upb_env_init(upb_env *e) {
-  upb_arena_init(&e->arena_);
-  upb_env_initonly(e);
-}
-
-void upb_env_init2(upb_env *e, void *mem, size_t n, upb_alloc *alloc) {
-  upb_arena_init2(&e->arena_, mem, n, alloc);
-  upb_env_initonly(e);
-}
-
-void upb_env_uninit(upb_env *e) {
-  upb_arena_uninit(&e->arena_);
-}
-
-void upb_env_seterrorfunc(upb_env *e, upb_error_func *func, void *ud) {
-  e->error_func_ = func;
-  e->error_ud_ = ud;
-}
-
-void upb_env_reporterrorsto(upb_env *e, upb_status *s) {
-  e->error_func_ = &write_err_to;
-  e->error_ud_ = s;
-}
-
-bool upb_env_reporterror(upb_env *e, const upb_status *status) {
-  e->ok_ = false;
-  return e->error_func_(e->error_ud_, status);
-}
-
-void *upb_env_malloc(upb_env *e, size_t size) {
-  return upb_malloc(&e->arena_.alloc, size);
-}
-
-void *upb_env_realloc(upb_env *e, void *ptr, size_t oldsize, size_t size) {
-  return upb_realloc(&e->arena_.alloc, ptr, oldsize, size);
-}
-
-void upb_env_free(upb_env *e, void *ptr) {
-  upb_free(&e->arena_.alloc, ptr);
-}
-
-bool upb_env_addcleanup(upb_env *e, upb_cleanup_func *func, void *ud) {
-  return upb_arena_addcleanup(&e->arena_, func, ud);
-}
-
-size_t upb_env_bytesallocated(const upb_env *e) {
-  return upb_arena_bytesallocated(&e->arena_);
-}
-/* This file was generated by upbc (the upb compiler) from the input
- * file:
- *
- *     upb/descriptor/descriptor.proto
- *
- * Do not edit -- your changes will be discarded when the file is
- * regenerated. */
-
-
-static const upb_msgdef msgs[22];
-static const upb_fielddef fields[107];
-static const upb_enumdef enums[5];
-static const upb_tabent strentries[236];
-static const upb_tabent intentries[18];
-static const upb_tabval arrays[187];
-
-#ifdef UPB_DEBUG_REFS
-static upb_inttable reftables[268];
-#endif
-
-static const upb_msgdef msgs[22] = {
-  UPB_MSGDEF_INIT("google.protobuf.DescriptorProto", 41, 8, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[0], 11, 10), UPB_STRTABLE_INIT(10, 15, UPB_CTYPE_PTR, 4, &strentries[0]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[0], &reftables[1]),
-  UPB_MSGDEF_INIT("google.protobuf.DescriptorProto.ExtensionRange", 5, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[11], 3, 2), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[16]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[2], &reftables[3]),
-  UPB_MSGDEF_INIT("google.protobuf.DescriptorProto.ReservedRange", 5, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[14], 3, 2), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[20]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[4], &reftables[5]),
-  UPB_MSGDEF_INIT("google.protobuf.EnumDescriptorProto", 12, 2, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[17], 4, 3), UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_PTR, 2, &strentries[24]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[6], &reftables[7]),
-  UPB_MSGDEF_INIT("google.protobuf.EnumOptions", 9, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[0], &arrays[21], 4, 2), UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_PTR, 2, &strentries[28]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[8], &reftables[9]),
-  UPB_MSGDEF_INIT("google.protobuf.EnumValueDescriptorProto", 9, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[25], 4, 3), UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_PTR, 2, &strentries[32]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[10], &reftables[11]),
-  UPB_MSGDEF_INIT("google.protobuf.EnumValueOptions", 8, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[2], &arrays[29], 2, 1), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[36]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[12], &reftables[13]),
-  UPB_MSGDEF_INIT("google.protobuf.FieldDescriptorProto", 24, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[31], 11, 10), UPB_STRTABLE_INIT(10, 15, UPB_CTYPE_PTR, 4, &strentries[40]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[14], &reftables[15]),
-  UPB_MSGDEF_INIT("google.protobuf.FieldOptions", 13, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[4], &arrays[42], 11, 6), UPB_STRTABLE_INIT(7, 15, UPB_CTYPE_PTR, 4, &strentries[56]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[16], &reftables[17]),
-  UPB_MSGDEF_INIT("google.protobuf.FileDescriptorProto", 43, 6, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[53], 13, 12), UPB_STRTABLE_INIT(12, 15, UPB_CTYPE_PTR, 4, &strentries[72]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[18], &reftables[19]),
-  UPB_MSGDEF_INIT("google.protobuf.FileDescriptorSet", 7, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[66], 2, 1), UPB_STRTABLE_INIT(1, 3, UPB_CTYPE_PTR, 2, &strentries[88]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[20], &reftables[21]),
-  UPB_MSGDEF_INIT("google.protobuf.FileOptions", 38, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[6], &arrays[68], 42, 17), UPB_STRTABLE_INIT(18, 31, UPB_CTYPE_PTR, 5, &strentries[92]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[22], &reftables[23]),
-  UPB_MSGDEF_INIT("google.protobuf.MessageOptions", 11, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[8], &arrays[110], 8, 4), UPB_STRTABLE_INIT(5, 7, UPB_CTYPE_PTR, 3, &strentries[124]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[24], &reftables[25]),
-  UPB_MSGDEF_INIT("google.protobuf.MethodDescriptorProto", 16, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[118], 7, 6), UPB_STRTABLE_INIT(6, 7, UPB_CTYPE_PTR, 3, &strentries[132]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[26], &reftables[27]),
-  UPB_MSGDEF_INIT("google.protobuf.MethodOptions", 8, 1, UPB_INTTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &intentries[10], &arrays[125], 1, 0), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[140]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[28], &reftables[29]),
-  UPB_MSGDEF_INIT("google.protobuf.OneofDescriptorProto", 6, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[126], 2, 1), UPB_STRTABLE_INIT(1, 3, UPB_CTYPE_PTR, 2, &strentries[144]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[30], &reftables[31]),
-  UPB_MSGDEF_INIT("google.protobuf.ServiceDescriptorProto", 12, 2, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[128], 4, 3), UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_PTR, 2, &strentries[148]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[32], &reftables[33]),
-  UPB_MSGDEF_INIT("google.protobuf.ServiceOptions", 8, 1, UPB_INTTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &intentries[14], &arrays[132], 1, 0), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[152]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[34], &reftables[35]),
-  UPB_MSGDEF_INIT("google.protobuf.SourceCodeInfo", 7, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[133], 2, 1), UPB_STRTABLE_INIT(1, 3, UPB_CTYPE_PTR, 2, &strentries[156]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[36], &reftables[37]),
-  UPB_MSGDEF_INIT("google.protobuf.SourceCodeInfo.Location", 20, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[135], 7, 5), UPB_STRTABLE_INIT(5, 7, UPB_CTYPE_PTR, 3, &strentries[160]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[38], &reftables[39]),
-  UPB_MSGDEF_INIT("google.protobuf.UninterpretedOption", 19, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[142], 9, 7), UPB_STRTABLE_INIT(7, 15, UPB_CTYPE_PTR, 4, &strentries[168]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[40], &reftables[41]),
-  UPB_MSGDEF_INIT("google.protobuf.UninterpretedOption.NamePart", 7, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[151], 3, 2), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[184]), false, UPB_SYNTAX_PROTO2, UPB_WELLKNOWN_UNSPECIFIED, &reftables[42], &reftables[43]),
-};
-
-static const upb_fielddef fields[107] = {
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "aggregate_value", 8, &msgs[20], NULL, 16, 6, {0},&reftables[44], &reftables[45]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "allow_alias", 2, &msgs[4], NULL, 7, 1, {0},&reftables[46], &reftables[47]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "cc_enable_arenas", 31, &msgs[11], NULL, 24, 12, {0},&reftables[48], &reftables[49]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "cc_generic_services", 16, &msgs[11], NULL, 18, 6, {0},&reftables[50], &reftables[51]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "client_streaming", 5, &msgs[13], NULL, 14, 4, {0},&reftables[52], &reftables[53]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "csharp_namespace", 37, &msgs[11], NULL, 28, 14, {0},&reftables[54], &reftables[55]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_ENUM, 0, false, false, false, false, "ctype", 1, &msgs[8], (const upb_def*)(&enums[2]), 7, 1, {0},&reftables[56], &reftables[57]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "default_value", 7, &msgs[7], NULL, 17, 7, {0},&reftables[58], &reftables[59]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_STRING, 0, false, false, false, false, "dependency", 3, &msgs[9], NULL, 31, 8, {0},&reftables[60], &reftables[61]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 3, &msgs[8], NULL, 9, 3, {0},&reftables[62], &reftables[63]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 33, &msgs[14], NULL, 7, 1, {0},&reftables[64], &reftables[65]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 3, &msgs[12], NULL, 9, 3, {0},&reftables[66], &reftables[67]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 23, &msgs[11], NULL, 22, 10, {0},&reftables[68], &reftables[69]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 1, &msgs[6], NULL, 7, 1, {0},&reftables[70], &reftables[71]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 3, &msgs[4], NULL, 8, 2, {0},&reftables[72], &reftables[73]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 33, &msgs[17], NULL, 7, 1, {0},&reftables[74], &reftables[75]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_DOUBLE, 0, false, false, false, false, "double_value", 6, &msgs[20], NULL, 12, 4, {0},&reftables[76], &reftables[77]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "end", 2, &msgs[2], NULL, 4, 1, {0},&reftables[78], &reftables[79]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "end", 2, &msgs[1], NULL, 4, 1, {0},&reftables[80], &reftables[81]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "enum_type", 5, &msgs[9], (const upb_def*)(&msgs[3]), 14, 1, {0},&reftables[82], &reftables[83]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "enum_type", 4, &msgs[0], (const upb_def*)(&msgs[3]), 19, 2, {0},&reftables[84], &reftables[85]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "extendee", 2, &msgs[7], NULL, 8, 2, {0},&reftables[86], &reftables[87]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "extension", 6, &msgs[0], (const upb_def*)(&msgs[7]), 25, 4, {0},&reftables[88], &reftables[89]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "extension", 7, &msgs[9], (const upb_def*)(&msgs[7]), 20, 3, {0},&reftables[90], &reftables[91]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "extension_range", 5, &msgs[0], (const upb_def*)(&msgs[1]), 22, 3, {0},&reftables[92], &reftables[93]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "field", 2, &msgs[0], (const upb_def*)(&msgs[7]), 13, 0, {0},&reftables[94], &reftables[95]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "file", 1, &msgs[10], (const upb_def*)(&msgs[9]), 6, 0, {0},&reftables[96], &reftables[97]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "go_package", 11, &msgs[11], NULL, 15, 5, {0},&reftables[98], &reftables[99]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "identifier_value", 3, &msgs[20], NULL, 7, 1, {0},&reftables[100], &reftables[101]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "input_type", 2, &msgs[13], NULL, 8, 2, {0},&reftables[102], &reftables[103]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REQUIRED, UPB_TYPE_BOOL, 0, false, false, false, false, "is_extension", 2, &msgs[21], NULL, 6, 1, {0},&reftables[104], &reftables[105]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "java_generate_equals_and_hash", 20, &msgs[11], NULL, 21, 9, {0},&reftables[106], &reftables[107]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "java_generic_services", 17, &msgs[11], NULL, 19, 7, {0},&reftables[108], &reftables[109]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "java_multiple_files", 10, &msgs[11], NULL, 14, 4, {0},&reftables[110], &reftables[111]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "java_outer_classname", 8, &msgs[11], NULL, 10, 2, {0},&reftables[112], &reftables[113]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "java_package", 1, &msgs[11], NULL, 7, 1, {0},&reftables[114], &reftables[115]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "java_string_check_utf8", 27, &msgs[11], NULL, 23, 11, {0},&reftables[116], &reftables[117]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "javanano_use_deprecated_package", 38, &msgs[11], NULL, 31, 15, {0},&reftables[118], &reftables[119]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "json_name", 10, &msgs[7], NULL, 21, 9, {0},&reftables[120], &reftables[121]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_ENUM, 0, false, false, false, false, "jstype", 6, &msgs[8], (const upb_def*)(&enums[3]), 11, 5, {0},&reftables[122], &reftables[123]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_ENUM, 0, false, false, false, false, "label", 4, &msgs[7], (const upb_def*)(&enums[0]), 12, 4, {0},&reftables[124], &reftables[125]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "lazy", 5, &msgs[8], NULL, 10, 4, {0},&reftables[126], &reftables[127]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "leading_comments", 3, &msgs[19], NULL, 9, 2, {0},&reftables[128], &reftables[129]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_STRING, 0, false, false, false, false, "leading_detached_comments", 6, &msgs[19], NULL, 17, 4, {0},&reftables[130], &reftables[131]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "location", 1, &msgs[18], (const upb_def*)(&msgs[19]), 6, 0, {0},&reftables[132], &reftables[133]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "map_entry", 7, &msgs[12], NULL, 10, 4, {0},&reftables[134], &reftables[135]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "message_set_wire_format", 1, &msgs[12], NULL, 7, 1, {0},&reftables[136], &reftables[137]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "message_type", 4, &msgs[9], (const upb_def*)(&msgs[0]), 11, 0, {0},&reftables[138], &reftables[139]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "method", 2, &msgs[16], (const upb_def*)(&msgs[13]), 7, 0, {0},&reftables[140], &reftables[141]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "name", 2, &msgs[20], (const upb_def*)(&msgs[21]), 6, 0, {0},&reftables[142], &reftables[143]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[5], NULL, 5, 1, {0},&reftables[144], &reftables[145]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[9], NULL, 23, 6, {0},&reftables[146], &reftables[147]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[3], NULL, 9, 2, {0},&reftables[148], &reftables[149]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[16], NULL, 9, 2, {0},&reftables[150], &reftables[151]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[15], NULL, 3, 0, {0},&reftables[152], &reftables[153]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[13], NULL, 5, 1, {0},&reftables[154], &reftables[155]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[7], NULL, 5, 1, {0},&reftables[156], &reftables[157]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[0], NULL, 33, 8, {0},&reftables[158], &reftables[159]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REQUIRED, UPB_TYPE_STRING, 0, false, false, false, false, "name_part", 1, &msgs[21], NULL, 3, 0, {0},&reftables[160], &reftables[161]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT64, UPB_INTFMT_VARIABLE, false, false, false, false, "negative_int_value", 5, &msgs[20], NULL, 11, 3, {0},&reftables[162], &reftables[163]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "nested_type", 3, &msgs[0], (const upb_def*)(&msgs[0]), 16, 1, {0},&reftables[164], &reftables[165]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "no_standard_descriptor_accessor", 2, &msgs[12], NULL, 8, 2, {0},&reftables[166], &reftables[167]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "number", 3, &msgs[7], NULL, 11, 3, {0},&reftables[168], &reftables[169]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "number", 2, &msgs[5], NULL, 8, 2, {0},&reftables[170], &reftables[171]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "objc_class_prefix", 36, &msgs[11], NULL, 25, 13, {0},&reftables[172], &reftables[173]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "oneof_decl", 8, &msgs[0], (const upb_def*)(&msgs[15]), 29, 6, {0},&reftables[174], &reftables[175]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "oneof_index", 9, &msgs[7], NULL, 20, 8, {0},&reftables[176], &reftables[177]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_ENUM, 0, false, false, false, false, "optimize_for", 9, &msgs[11], (const upb_def*)(&enums[4]), 13, 3, {0},&reftables[178], &reftables[179]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 7, &msgs[0], (const upb_def*)(&msgs[12]), 26, 5, {0},&reftables[180], &reftables[181]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 8, &msgs[9], (const upb_def*)(&msgs[11]), 21, 4, {0},&reftables[182], &reftables[183]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 8, &msgs[7], (const upb_def*)(&msgs[8]), 4, 0, {0},&reftables[184], &reftables[185]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 4, &msgs[13], (const upb_def*)(&msgs[14]), 4, 0, {0},&reftables[186], &reftables[187]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 3, &msgs[16], (const upb_def*)(&msgs[17]), 8, 1, {0},&reftables[188], &reftables[189]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 3, &msgs[3], (const upb_def*)(&msgs[4]), 8, 1, {0},&reftables[190], &reftables[191]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 3, &msgs[5], (const upb_def*)(&msgs[6]), 4, 0, {0},&reftables[192], &reftables[193]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "output_type", 3, &msgs[13], NULL, 11, 3, {0},&reftables[194], &reftables[195]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "package", 2, &msgs[9], NULL, 26, 7, {0},&reftables[196], &reftables[197]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "packed", 2, &msgs[8], NULL, 8, 2, {0},&reftables[198], &reftables[199]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, true, "path", 1, &msgs[19], NULL, 5, 0, {0},&reftables[200], &reftables[201]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "php_class_prefix", 40, &msgs[11], NULL, 32, 16, {0},&reftables[202], &reftables[203]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "php_namespace", 41, &msgs[11], NULL, 35, 17, {0},&reftables[204], &reftables[205]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_UINT64, UPB_INTFMT_VARIABLE, false, false, false, false, "positive_int_value", 4, &msgs[20], NULL, 10, 2, {0},&reftables[206], &reftables[207]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "public_dependency", 10, &msgs[9], NULL, 36, 9, {0},&reftables[208], &reftables[209]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "py_generic_services", 18, &msgs[11], NULL, 20, 8, {0},&reftables[210], &reftables[211]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_STRING, 0, false, false, false, false, "reserved_name", 10, &msgs[0], NULL, 38, 9, {0},&reftables[212], &reftables[213]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "reserved_range", 9, &msgs[0], (const upb_def*)(&msgs[2]), 32, 7, {0},&reftables[214], &reftables[215]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "server_streaming", 6, &msgs[13], NULL, 15, 5, {0},&reftables[216], &reftables[217]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "service", 6, &msgs[9], (const upb_def*)(&msgs[16]), 17, 2, {0},&reftables[218], &reftables[219]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "source_code_info", 9, &msgs[9], (const upb_def*)(&msgs[18]), 22, 5, {0},&reftables[220], &reftables[221]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, true, "span", 2, &msgs[19], NULL, 8, 1, {0},&reftables[222], &reftables[223]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "start", 1, &msgs[2], NULL, 3, 0, {0},&reftables[224], &reftables[225]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "start", 1, &msgs[1], NULL, 3, 0, {0},&reftables[226], &reftables[227]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BYTES, 0, false, false, false, false, "string_value", 7, &msgs[20], NULL, 13, 5, {0},&reftables[228], &reftables[229]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "syntax", 12, &msgs[9], NULL, 40, 11, {0},&reftables[230], &reftables[231]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "trailing_comments", 4, &msgs[19], NULL, 12, 3, {0},&reftables[232], &reftables[233]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_ENUM, 0, false, false, false, false, "type", 5, &msgs[7], (const upb_def*)(&enums[1]), 13, 5, {0},&reftables[234], &reftables[235]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "type_name", 6, &msgs[7], NULL, 14, 6, {0},&reftables[236], &reftables[237]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[12], (const upb_def*)(&msgs[20]), 6, 0, {0},&reftables[238], &reftables[239]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[17], (const upb_def*)(&msgs[20]), 6, 0, {0},&reftables[240], &reftables[241]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[11], (const upb_def*)(&msgs[20]), 6, 0, {0},&reftables[242], &reftables[243]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[14], (const upb_def*)(&msgs[20]), 6, 0, {0},&reftables[244], &reftables[245]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[8], (const upb_def*)(&msgs[20]), 6, 0, {0},&reftables[246], &reftables[247]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[6], (const upb_def*)(&msgs[20]), 6, 0, {0},&reftables[248], &reftables[249]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[4], (const upb_def*)(&msgs[20]), 6, 0, {0},&reftables[250], &reftables[251]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "value", 2, &msgs[3], (const upb_def*)(&msgs[5]), 7, 0, {0},&reftables[252], &reftables[253]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "weak", 10, &msgs[8], NULL, 12, 6, {0},&reftables[254], &reftables[255]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "weak_dependency", 11, &msgs[9], NULL, 39, 10, {0},&reftables[256], &reftables[257]),
-};
-
-static const upb_enumdef enums[5] = {
-  UPB_ENUMDEF_INIT("google.protobuf.FieldDescriptorProto.Label", UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_INT32, 2, &strentries[188]), UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_CSTR, 0, NULL, &arrays[154], 4, 3), 0, &reftables[258], &reftables[259]),
-  UPB_ENUMDEF_INIT("google.protobuf.FieldDescriptorProto.Type", UPB_STRTABLE_INIT(18, 31, UPB_CTYPE_INT32, 5, &strentries[192]), UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_CSTR, 0, NULL, &arrays[158], 19, 18), 0, &reftables[260], &reftables[261]),
-  UPB_ENUMDEF_INIT("google.protobuf.FieldOptions.CType", UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_INT32, 2, &strentries[224]), UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_CSTR, 0, NULL, &arrays[177], 3, 3), 0, &reftables[262], &reftables[263]),
-  UPB_ENUMDEF_INIT("google.protobuf.FieldOptions.JSType", UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_INT32, 2, &strentries[228]), UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_CSTR, 0, NULL, &arrays[180], 3, 3), 0, &reftables[264], &reftables[265]),
-  UPB_ENUMDEF_INIT("google.protobuf.FileOptions.OptimizeMode", UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_INT32, 2, &strentries[232]), UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_CSTR, 0, NULL, &arrays[183], 4, 3), 0, &reftables[266], &reftables[267]),
-};
-
-static const upb_tabent strentries[236] = {
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-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
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-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
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-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\013", "\000", "\000", "\000", "nested_type"), UPB_TABVALUE_PTR_INIT(&fields[60]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
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-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[68]), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "oneof_decl"), UPB_TABVALUE_PTR_INIT(&fields[65]), NULL},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "enum_type"), UPB_TABVALUE_PTR_INIT(&fields[20]), &strentries[13]},
-  {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "start"), UPB_TABVALUE_PTR_INIT(&fields[91]), NULL},
-  {UPB_TABKEY_STR("\003", "\000", "\000", "\000", "end"), UPB_TABVALUE_PTR_INIT(&fields[18]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "start"), UPB_TABVALUE_PTR_INIT(&fields[90]), NULL},
-  {UPB_TABKEY_STR("\003", "\000", "\000", "\000", "end"), UPB_TABVALUE_PTR_INIT(&fields[17]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "value"), UPB_TABVALUE_PTR_INIT(&fields[104]), NULL},
-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[73]), NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[52]), &strentries[26]},
-  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[103]), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[14]), NULL},
-  {UPB_TABKEY_STR("\013", "\000", "\000", "\000", "allow_alias"), UPB_TABVALUE_PTR_INIT(&fields[1]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\006", "\000", "\000", "\000", "number"), UPB_TABVALUE_PTR_INIT(&fields[63]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[74]), NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[50]), &strentries[34]},
-  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[102]), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[13]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\013", "\000", "\000", "\000", "oneof_index"), UPB_TABVALUE_PTR_INIT(&fields[66]), NULL},
-  {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "label"), UPB_TABVALUE_PTR_INIT(&fields[40]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[56]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\006", "\000", "\000", "\000", "number"), UPB_TABVALUE_PTR_INIT(&fields[62]), &strentries[53]},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\010", "\000", "\000", "\000", "extendee"), UPB_TABVALUE_PTR_INIT(&fields[21]), NULL},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "type_name"), UPB_TABVALUE_PTR_INIT(&fields[96]), NULL},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "json_name"), UPB_TABVALUE_PTR_INIT(&fields[38]), NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "type"), UPB_TABVALUE_PTR_INIT(&fields[95]), &strentries[50]},
-  {UPB_TABKEY_STR("\015", "\000", "\000", "\000", "default_value"), UPB_TABVALUE_PTR_INIT(&fields[7]), NULL},
-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[70]), NULL},
-  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[101]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "weak"), UPB_TABVALUE_PTR_INIT(&fields[105]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\006", "\000", "\000", "\000", "packed"), UPB_TABVALUE_PTR_INIT(&fields[77]), NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "lazy"), UPB_TABVALUE_PTR_INIT(&fields[41]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "ctype"), UPB_TABVALUE_PTR_INIT(&fields[6]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\006", "\000", "\000", "\000", "jstype"), UPB_TABVALUE_PTR_INIT(&fields[39]), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[9]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "extension"), UPB_TABVALUE_PTR_INIT(&fields[23]), NULL},
-  {UPB_TABKEY_STR("\017", "\000", "\000", "\000", "weak_dependency"), UPB_TABVALUE_PTR_INIT(&fields[106]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[51]), NULL},
-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "service"), UPB_TABVALUE_PTR_INIT(&fields[87]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\020", "\000", "\000", "\000", "source_code_info"), UPB_TABVALUE_PTR_INIT(&fields[88]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\006", "\000", "\000", "\000", "syntax"), UPB_TABVALUE_PTR_INIT(&fields[93]), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "dependency"), UPB_TABVALUE_PTR_INIT(&fields[8]), NULL},
-  {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "message_type"), UPB_TABVALUE_PTR_INIT(&fields[47]), NULL},
-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "package"), UPB_TABVALUE_PTR_INIT(&fields[76]), NULL},
-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[69]), &strentries[86]},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "enum_type"), UPB_TABVALUE_PTR_INIT(&fields[19]), NULL},
-  {UPB_TABKEY_STR("\021", "\000", "\000", "\000", "public_dependency"), UPB_TABVALUE_PTR_INIT(&fields[82]), &strentries[85]},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "file"), UPB_TABVALUE_PTR_INIT(&fields[26]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\023", "\000", "\000", "\000", "cc_generic_services"), UPB_TABVALUE_PTR_INIT(&fields[3]), NULL},
-  {UPB_TABKEY_STR("\020", "\000", "\000", "\000", "csharp_namespace"), UPB_TABVALUE_PTR_INIT(&fields[5]), &strentries[116]},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "go_package"), UPB_TABVALUE_PTR_INIT(&fields[27]), NULL},
-  {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "java_package"), UPB_TABVALUE_PTR_INIT(&fields[35]), &strentries[120]},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "java_outer_classname"), UPB_TABVALUE_PTR_INIT(&fields[34]), NULL},
-  {UPB_TABKEY_STR("\015", "\000", "\000", "\000", "php_namespace"), UPB_TABVALUE_PTR_INIT(&fields[80]), &strentries[113]},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\023", "\000", "\000", "\000", "java_multiple_files"), UPB_TABVALUE_PTR_INIT(&fields[33]), &strentries[117]},
-  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[99]), NULL},
-  {UPB_TABKEY_STR("\025", "\000", "\000", "\000", "java_generic_services"), UPB_TABVALUE_PTR_INIT(&fields[32]), &strentries[118]},
-  {UPB_TABKEY_STR("\035", "\000", "\000", "\000", "java_generate_equals_and_hash"), UPB_TABVALUE_PTR_INIT(&fields[31]), NULL},
-  {UPB_TABKEY_STR("\020", "\000", "\000", "\000", "php_class_prefix"), UPB_TABVALUE_PTR_INIT(&fields[79]), NULL},
-  {UPB_TABKEY_STR("\037", "\000", "\000", "\000", "javanano_use_deprecated_package"), UPB_TABVALUE_PTR_INIT(&fields[37]), &strentries[123]},
-  {UPB_TABKEY_STR("\023", "\000", "\000", "\000", "py_generic_services"), UPB_TABVALUE_PTR_INIT(&fields[83]), NULL},
-  {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "optimize_for"), UPB_TABVALUE_PTR_INIT(&fields[67]), NULL},
-  {UPB_TABKEY_STR("\026", "\000", "\000", "\000", "java_string_check_utf8"), UPB_TABVALUE_PTR_INIT(&fields[36]), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[12]), &strentries[119]},
-  {UPB_TABKEY_STR("\021", "\000", "\000", "\000", "objc_class_prefix"), UPB_TABVALUE_PTR_INIT(&fields[64]), NULL},
-  {UPB_TABKEY_STR("\020", "\000", "\000", "\000", "cc_enable_arenas"), UPB_TABVALUE_PTR_INIT(&fields[2]), NULL},
-  {UPB_TABKEY_STR("\027", "\000", "\000", "\000", "message_set_wire_format"), UPB_TABVALUE_PTR_INIT(&fields[46]), &strentries[128]},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
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-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
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-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[54]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
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-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
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-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
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-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
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-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "span"), UPB_TABVALUE_PTR_INIT(&fields[89]), &strentries[167]},
-  {UPB_TABKEY_STR("\031", "\000", "\000", "\000", "leading_detached_comments"), UPB_TABVALUE_PTR_INIT(&fields[43]), &strentries[165]},
-  {UPB_TABKEY_STR("\021", "\000", "\000", "\000", "trailing_comments"), UPB_TABVALUE_PTR_INIT(&fields[94]), NULL},
-  {UPB_TABKEY_STR("\020", "\000", "\000", "\000", "leading_comments"), UPB_TABVALUE_PTR_INIT(&fields[42]), &strentries[164]},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "path"), UPB_TABVALUE_PTR_INIT(&fields[78]), NULL},
-  {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "double_value"), UPB_TABVALUE_PTR_INIT(&fields[16]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[49]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\022", "\000", "\000", "\000", "negative_int_value"), UPB_TABVALUE_PTR_INIT(&fields[59]), NULL},
-  {UPB_TABKEY_STR("\017", "\000", "\000", "\000", "aggregate_value"), UPB_TABVALUE_PTR_INIT(&fields[0]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\022", "\000", "\000", "\000", "positive_int_value"), UPB_TABVALUE_PTR_INIT(&fields[81]), NULL},
-  {UPB_TABKEY_STR("\020", "\000", "\000", "\000", "identifier_value"), UPB_TABVALUE_PTR_INIT(&fields[28]), NULL},
-  {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "string_value"), UPB_TABVALUE_PTR_INIT(&fields[92]), &strentries[182]},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "is_extension"), UPB_TABVALUE_PTR_INIT(&fields[30]), NULL},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "name_part"), UPB_TABVALUE_PTR_INIT(&fields[58]), NULL},
-  {UPB_TABKEY_STR("\016", "\000", "\000", "\000", "LABEL_REQUIRED"), UPB_TABVALUE_INT_INIT(2), &strentries[190]},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\016", "\000", "\000", "\000", "LABEL_REPEATED"), UPB_TABVALUE_INT_INIT(3), NULL},
-  {UPB_TABKEY_STR("\016", "\000", "\000", "\000", "LABEL_OPTIONAL"), UPB_TABVALUE_INT_INIT(1), NULL},
-  {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "TYPE_FIXED64"), UPB_TABVALUE_INT_INIT(6), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\013", "\000", "\000", "\000", "TYPE_STRING"), UPB_TABVALUE_INT_INIT(9), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "TYPE_FLOAT"), UPB_TABVALUE_INT_INIT(2), &strentries[221]},
-  {UPB_TABKEY_STR("\013", "\000", "\000", "\000", "TYPE_DOUBLE"), UPB_TABVALUE_INT_INIT(1), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "TYPE_INT32"), UPB_TABVALUE_INT_INIT(5), NULL},
-  {UPB_TABKEY_STR("\015", "\000", "\000", "\000", "TYPE_SFIXED32"), UPB_TABVALUE_INT_INIT(15), NULL},
-  {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "TYPE_FIXED32"), UPB_TABVALUE_INT_INIT(7), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "TYPE_MESSAGE"), UPB_TABVALUE_INT_INIT(11), &strentries[222]},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "TYPE_INT64"), UPB_TABVALUE_INT_INIT(3), &strentries[219]},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "TYPE_ENUM"), UPB_TABVALUE_INT_INIT(14), NULL},
-  {UPB_TABKEY_STR("\013", "\000", "\000", "\000", "TYPE_UINT32"), UPB_TABVALUE_INT_INIT(13), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\013", "\000", "\000", "\000", "TYPE_UINT64"), UPB_TABVALUE_INT_INIT(4), &strentries[218]},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\015", "\000", "\000", "\000", "TYPE_SFIXED64"), UPB_TABVALUE_INT_INIT(16), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "TYPE_BYTES"), UPB_TABVALUE_INT_INIT(12), NULL},
-  {UPB_TABKEY_STR("\013", "\000", "\000", "\000", "TYPE_SINT64"), UPB_TABVALUE_INT_INIT(18), NULL},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "TYPE_BOOL"), UPB_TABVALUE_INT_INIT(8), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "TYPE_GROUP"), UPB_TABVALUE_INT_INIT(10), NULL},
-  {UPB_TABKEY_STR("\013", "\000", "\000", "\000", "TYPE_SINT32"), UPB_TABVALUE_INT_INIT(17), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "CORD"), UPB_TABVALUE_INT_INIT(1), NULL},
-  {UPB_TABKEY_STR("\006", "\000", "\000", "\000", "STRING"), UPB_TABVALUE_INT_INIT(0), &strentries[225]},
-  {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "STRING_PIECE"), UPB_TABVALUE_INT_INIT(2), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "JS_NORMAL"), UPB_TABVALUE_INT_INIT(0), NULL},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "JS_NUMBER"), UPB_TABVALUE_INT_INIT(2), NULL},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "JS_STRING"), UPB_TABVALUE_INT_INIT(1), NULL},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "CODE_SIZE"), UPB_TABVALUE_INT_INIT(2), NULL},
-  {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "SPEED"), UPB_TABVALUE_INT_INIT(1), &strentries[235]},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "LITE_RUNTIME"), UPB_TABVALUE_INT_INIT(3), NULL},
-};
-
-static const upb_tabent intentries[18] = {
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[103]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[102]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[101]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[99]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[97]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(33), UPB_TABVALUE_PTR_INIT(&fields[10]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[100]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(33), UPB_TABVALUE_PTR_INIT(&fields[15]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[98]), NULL},
-};
-
-static const upb_tabval arrays[187] = {
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[57]),
-  UPB_TABVALUE_PTR_INIT(&fields[25]),
-  UPB_TABVALUE_PTR_INIT(&fields[60]),
-  UPB_TABVALUE_PTR_INIT(&fields[20]),
-  UPB_TABVALUE_PTR_INIT(&fields[24]),
-  UPB_TABVALUE_PTR_INIT(&fields[22]),
-  UPB_TABVALUE_PTR_INIT(&fields[68]),
-  UPB_TABVALUE_PTR_INIT(&fields[65]),
-  UPB_TABVALUE_PTR_INIT(&fields[85]),
-  UPB_TABVALUE_PTR_INIT(&fields[84]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[91]),
-  UPB_TABVALUE_PTR_INIT(&fields[18]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[90]),
-  UPB_TABVALUE_PTR_INIT(&fields[17]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[52]),
-  UPB_TABVALUE_PTR_INIT(&fields[104]),
-  UPB_TABVALUE_PTR_INIT(&fields[73]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[1]),
-  UPB_TABVALUE_PTR_INIT(&fields[14]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[50]),
-  UPB_TABVALUE_PTR_INIT(&fields[63]),
-  UPB_TABVALUE_PTR_INIT(&fields[74]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[13]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[56]),
-  UPB_TABVALUE_PTR_INIT(&fields[21]),
-  UPB_TABVALUE_PTR_INIT(&fields[62]),
-  UPB_TABVALUE_PTR_INIT(&fields[40]),
-  UPB_TABVALUE_PTR_INIT(&fields[95]),
-  UPB_TABVALUE_PTR_INIT(&fields[96]),
-  UPB_TABVALUE_PTR_INIT(&fields[7]),
-  UPB_TABVALUE_PTR_INIT(&fields[70]),
-  UPB_TABVALUE_PTR_INIT(&fields[66]),
-  UPB_TABVALUE_PTR_INIT(&fields[38]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[6]),
-  UPB_TABVALUE_PTR_INIT(&fields[77]),
-  UPB_TABVALUE_PTR_INIT(&fields[9]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[41]),
-  UPB_TABVALUE_PTR_INIT(&fields[39]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[105]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[51]),
-  UPB_TABVALUE_PTR_INIT(&fields[76]),
-  UPB_TABVALUE_PTR_INIT(&fields[8]),
-  UPB_TABVALUE_PTR_INIT(&fields[47]),
-  UPB_TABVALUE_PTR_INIT(&fields[19]),
-  UPB_TABVALUE_PTR_INIT(&fields[87]),
-  UPB_TABVALUE_PTR_INIT(&fields[23]),
-  UPB_TABVALUE_PTR_INIT(&fields[69]),
-  UPB_TABVALUE_PTR_INIT(&fields[88]),
-  UPB_TABVALUE_PTR_INIT(&fields[82]),
-  UPB_TABVALUE_PTR_INIT(&fields[106]),
-  UPB_TABVALUE_PTR_INIT(&fields[93]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[26]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[35]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[34]),
-  UPB_TABVALUE_PTR_INIT(&fields[67]),
-  UPB_TABVALUE_PTR_INIT(&fields[33]),
-  UPB_TABVALUE_PTR_INIT(&fields[27]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[3]),
-  UPB_TABVALUE_PTR_INIT(&fields[32]),
-  UPB_TABVALUE_PTR_INIT(&fields[83]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[31]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[12]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[36]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[2]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[64]),
-  UPB_TABVALUE_PTR_INIT(&fields[5]),
-  UPB_TABVALUE_PTR_INIT(&fields[37]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[79]),
-  UPB_TABVALUE_PTR_INIT(&fields[80]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[46]),
-  UPB_TABVALUE_PTR_INIT(&fields[61]),
-  UPB_TABVALUE_PTR_INIT(&fields[11]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[45]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[55]),
-  UPB_TABVALUE_PTR_INIT(&fields[29]),
-  UPB_TABVALUE_PTR_INIT(&fields[75]),
-  UPB_TABVALUE_PTR_INIT(&fields[71]),
-  UPB_TABVALUE_PTR_INIT(&fields[4]),
-  UPB_TABVALUE_PTR_INIT(&fields[86]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[54]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[53]),
-  UPB_TABVALUE_PTR_INIT(&fields[48]),
-  UPB_TABVALUE_PTR_INIT(&fields[72]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[44]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[78]),
-  UPB_TABVALUE_PTR_INIT(&fields[89]),
-  UPB_TABVALUE_PTR_INIT(&fields[42]),
-  UPB_TABVALUE_PTR_INIT(&fields[94]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[43]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[49]),
-  UPB_TABVALUE_PTR_INIT(&fields[28]),
-  UPB_TABVALUE_PTR_INIT(&fields[81]),
-  UPB_TABVALUE_PTR_INIT(&fields[59]),
-  UPB_TABVALUE_PTR_INIT(&fields[16]),
-  UPB_TABVALUE_PTR_INIT(&fields[92]),
-  UPB_TABVALUE_PTR_INIT(&fields[0]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[58]),
-  UPB_TABVALUE_PTR_INIT(&fields[30]),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT("LABEL_OPTIONAL"),
-  UPB_TABVALUE_PTR_INIT("LABEL_REQUIRED"),
-  UPB_TABVALUE_PTR_INIT("LABEL_REPEATED"),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT("TYPE_DOUBLE"),
-  UPB_TABVALUE_PTR_INIT("TYPE_FLOAT"),
-  UPB_TABVALUE_PTR_INIT("TYPE_INT64"),
-  UPB_TABVALUE_PTR_INIT("TYPE_UINT64"),
-  UPB_TABVALUE_PTR_INIT("TYPE_INT32"),
-  UPB_TABVALUE_PTR_INIT("TYPE_FIXED64"),
-  UPB_TABVALUE_PTR_INIT("TYPE_FIXED32"),
-  UPB_TABVALUE_PTR_INIT("TYPE_BOOL"),
-  UPB_TABVALUE_PTR_INIT("TYPE_STRING"),
-  UPB_TABVALUE_PTR_INIT("TYPE_GROUP"),
-  UPB_TABVALUE_PTR_INIT("TYPE_MESSAGE"),
-  UPB_TABVALUE_PTR_INIT("TYPE_BYTES"),
-  UPB_TABVALUE_PTR_INIT("TYPE_UINT32"),
-  UPB_TABVALUE_PTR_INIT("TYPE_ENUM"),
-  UPB_TABVALUE_PTR_INIT("TYPE_SFIXED32"),
-  UPB_TABVALUE_PTR_INIT("TYPE_SFIXED64"),
-  UPB_TABVALUE_PTR_INIT("TYPE_SINT32"),
-  UPB_TABVALUE_PTR_INIT("TYPE_SINT64"),
-  UPB_TABVALUE_PTR_INIT("STRING"),
-  UPB_TABVALUE_PTR_INIT("CORD"),
-  UPB_TABVALUE_PTR_INIT("STRING_PIECE"),
-  UPB_TABVALUE_PTR_INIT("JS_NORMAL"),
-  UPB_TABVALUE_PTR_INIT("JS_STRING"),
-  UPB_TABVALUE_PTR_INIT("JS_NUMBER"),
-  UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT("SPEED"),
-  UPB_TABVALUE_PTR_INIT("CODE_SIZE"),
-  UPB_TABVALUE_PTR_INIT("LITE_RUNTIME"),
-};
-
-#ifdef UPB_DEBUG_REFS
-static upb_inttable reftables[268] = {
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-};
-#endif
-
-static const upb_msgdef *refm(const upb_msgdef *m, const void *owner) {
-  upb_msgdef_ref(m, owner);
-  return m;
-}
-
-static const upb_enumdef *refe(const upb_enumdef *e, const void *owner) {
-  upb_enumdef_ref(e, owner);
-  return e;
-}
-
-/* Public API. */
-const upb_msgdef *upbdefs_google_protobuf_DescriptorProto_get(const void *owner) { return refm(&msgs[0], owner); }
-const upb_msgdef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_get(const void *owner) { return refm(&msgs[1], owner); }
-const upb_msgdef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_get(const void *owner) { return refm(&msgs[2], owner); }
-const upb_msgdef *upbdefs_google_protobuf_EnumDescriptorProto_get(const void *owner) { return refm(&msgs[3], owner); }
-const upb_msgdef *upbdefs_google_protobuf_EnumOptions_get(const void *owner) { return refm(&msgs[4], owner); }
-const upb_msgdef *upbdefs_google_protobuf_EnumValueDescriptorProto_get(const void *owner) { return refm(&msgs[5], owner); }
-const upb_msgdef *upbdefs_google_protobuf_EnumValueOptions_get(const void *owner) { return refm(&msgs[6], owner); }
-const upb_msgdef *upbdefs_google_protobuf_FieldDescriptorProto_get(const void *owner) { return refm(&msgs[7], owner); }
-const upb_msgdef *upbdefs_google_protobuf_FieldOptions_get(const void *owner) { return refm(&msgs[8], owner); }
-const upb_msgdef *upbdefs_google_protobuf_FileDescriptorProto_get(const void *owner) { return refm(&msgs[9], owner); }
-const upb_msgdef *upbdefs_google_protobuf_FileDescriptorSet_get(const void *owner) { return refm(&msgs[10], owner); }
-const upb_msgdef *upbdefs_google_protobuf_FileOptions_get(const void *owner) { return refm(&msgs[11], owner); }
-const upb_msgdef *upbdefs_google_protobuf_MessageOptions_get(const void *owner) { return refm(&msgs[12], owner); }
-const upb_msgdef *upbdefs_google_protobuf_MethodDescriptorProto_get(const void *owner) { return refm(&msgs[13], owner); }
-const upb_msgdef *upbdefs_google_protobuf_MethodOptions_get(const void *owner) { return refm(&msgs[14], owner); }
-const upb_msgdef *upbdefs_google_protobuf_OneofDescriptorProto_get(const void *owner) { return refm(&msgs[15], owner); }
-const upb_msgdef *upbdefs_google_protobuf_ServiceDescriptorProto_get(const void *owner) { return refm(&msgs[16], owner); }
-const upb_msgdef *upbdefs_google_protobuf_ServiceOptions_get(const void *owner) { return refm(&msgs[17], owner); }
-const upb_msgdef *upbdefs_google_protobuf_SourceCodeInfo_get(const void *owner) { return refm(&msgs[18], owner); }
-const upb_msgdef *upbdefs_google_protobuf_SourceCodeInfo_Location_get(const void *owner) { return refm(&msgs[19], owner); }
-const upb_msgdef *upbdefs_google_protobuf_UninterpretedOption_get(const void *owner) { return refm(&msgs[20], owner); }
-const upb_msgdef *upbdefs_google_protobuf_UninterpretedOption_NamePart_get(const void *owner) { return refm(&msgs[21], owner); }
-
-const upb_enumdef *upbdefs_google_protobuf_FieldDescriptorProto_Label_get(const void *owner) { return refe(&enums[0], owner); }
-const upb_enumdef *upbdefs_google_protobuf_FieldDescriptorProto_Type_get(const void *owner) { return refe(&enums[1], owner); }
-const upb_enumdef *upbdefs_google_protobuf_FieldOptions_CType_get(const void *owner) { return refe(&enums[2], owner); }
-const upb_enumdef *upbdefs_google_protobuf_FieldOptions_JSType_get(const void *owner) { return refe(&enums[3], owner); }
-const upb_enumdef *upbdefs_google_protobuf_FileOptions_OptimizeMode_get(const void *owner) { return refe(&enums[4], owner); }
-/*
-** XXX: The routines in this file that consume a string do not currently
-** support having the string span buffers.  In the future, as upb_sink and
-** its buffering/sharing functionality evolve there should be an easy and
-** idiomatic way of correctly handling this case.  For now, we accept this
-** limitation since we currently only parse descriptors from single strings.
-*/
-
-
-#include <errno.h>
-#include <stdlib.h>
-#include <string.h>
-
-/* Compares a NULL-terminated string with a non-NULL-terminated string. */
-static bool upb_streq(const char *str, const char *buf, size_t n) {
-  return strlen(str) == n && memcmp(str, buf, n) == 0;
-}
-
-/* We keep a stack of all the messages scopes we are currently in, as well as
- * the top-level file scope.  This is necessary to correctly qualify the
- * definitions that are contained inside.  "name" tracks the name of the
- * message or package (a bare name -- not qualified by any enclosing scopes). */
-typedef struct {
-  char *name;
-  /* Index of the first def that is under this scope.  For msgdefs, the
-   * msgdef itself is at start-1. */
-  int start;
-  uint32_t oneof_start;
-  uint32_t oneof_index;
-} upb_descreader_frame;
-
-/* The maximum number of nested declarations that are allowed, ie.
- * message Foo {
- *   message Bar {
- *     message Baz {
- *     }
- *   }
- * }
- *
- * This is a resource limit that affects how big our runtime stack can grow.
- * TODO: make this a runtime-settable property of the Reader instance. */
-#define UPB_MAX_MESSAGE_NESTING 64
-
-struct upb_descreader {
-  upb_sink sink;
-  upb_inttable files;
-  upb_strtable files_by_name;
-  upb_filedef *file;  /* The last file in files. */
-  upb_descreader_frame stack[UPB_MAX_MESSAGE_NESTING];
-  int stack_len;
-  upb_inttable oneofs;
-
-  uint32_t number;
-  char *name;
-  bool saw_number;
-  bool saw_name;
-
-  char *default_string;
-
-  upb_fielddef *f;
-};
-
-static char *upb_gstrndup(const char *buf, size_t n) {
-  char *ret = upb_gmalloc(n + 1);
-  if (!ret) return NULL;
-  memcpy(ret, buf, n);
-  ret[n] = '\0';
-  return ret;
-}
-
-/* Returns a newly allocated string that joins input strings together, for
- * example:
- *   join("Foo.Bar", "Baz") -> "Foo.Bar.Baz"
- *   join("", "Baz") -> "Baz"
- * Caller owns a ref on the returned string. */
-static char *upb_join(const char *base, const char *name) {
-  if (!base || strlen(base) == 0) {
-    return upb_gstrdup(name);
-  } else {
-    char *ret = upb_gmalloc(strlen(base) + strlen(name) + 2);
-    if (!ret) {
-      return NULL;
-    }
-    ret[0] = '\0';
-    strcat(ret, base);
-    strcat(ret, ".");
-    strcat(ret, name);
-    return ret;
-  }
-}
-
-/* Qualify the defname for all defs starting with offset "start" with "str". */
-static bool upb_descreader_qualify(upb_filedef *f, char *str, int32_t start) {
-  size_t i;
-  for (i = start; i < upb_filedef_defcount(f); i++) {
-    upb_def *def = upb_filedef_mutabledef(f, i);
-    char *name = upb_join(str, upb_def_fullname(def));
-    if (!name) {
-      /* Need better logic here; at this point we've qualified some names but
-       * not others. */
-      return false;
-    }
-    upb_def_setfullname(def, name, NULL);
-    upb_gfree(name);
-  }
-  return true;
-}
-
-
-/* upb_descreader  ************************************************************/
-
-static upb_msgdef *upb_descreader_top(upb_descreader *r) {
-  int index;
-  UPB_ASSERT(r->stack_len > 1);
-  index = r->stack[r->stack_len-1].start - 1;
-  UPB_ASSERT(index >= 0);
-  return upb_downcast_msgdef_mutable(upb_filedef_mutabledef(r->file, index));
-}
-
-static upb_def *upb_descreader_last(upb_descreader *r) {
-  return upb_filedef_mutabledef(r->file, upb_filedef_defcount(r->file) - 1);
-}
-
-/* Start/end handlers for FileDescriptorProto and DescriptorProto (the two
- * entities that have names and can contain sub-definitions. */
-void upb_descreader_startcontainer(upb_descreader *r) {
-  upb_descreader_frame *f = &r->stack[r->stack_len++];
-  f->start = upb_filedef_defcount(r->file);
-  f->oneof_start = upb_inttable_count(&r->oneofs);
-  f->oneof_index = 0;
-  f->name = NULL;
-}
-
-bool upb_descreader_endcontainer(upb_descreader *r) {
-  upb_descreader_frame *f = &r->stack[r->stack_len - 1];
-
-  while (upb_inttable_count(&r->oneofs) > f->oneof_start) {
-    upb_oneofdef *o = upb_value_getptr(upb_inttable_pop(&r->oneofs));
-    bool ok = upb_msgdef_addoneof(upb_descreader_top(r), o, &r->oneofs, NULL);
-    UPB_ASSERT(ok);
-  }
-
-  if (!upb_descreader_qualify(r->file, f->name, f->start)) {
-    return false;
-  }
-  upb_gfree(f->name);
-  f->name = NULL;
-
-  r->stack_len--;
-  return true;
-}
-
-void upb_descreader_setscopename(upb_descreader *r, char *str) {
-  upb_descreader_frame *f = &r->stack[r->stack_len-1];
-  upb_gfree(f->name);
-  f->name = str;
-}
-
-static upb_oneofdef *upb_descreader_getoneof(upb_descreader *r,
-                                             uint32_t index) {
-  bool found;
-  upb_value val;
-  upb_descreader_frame *f = &r->stack[r->stack_len-1];
-
-  /* DescriptorProto messages can be nested, so we will see the nested messages
-   * between when we see the FieldDescriptorProto and the OneofDescriptorProto.
-   * We need to preserve the oneofs in between these two things. */
-  index += f->oneof_start;
-
-  while (upb_inttable_count(&r->oneofs) <= index) {
-    upb_inttable_push(&r->oneofs, upb_value_ptr(upb_oneofdef_new(&r->oneofs)));
-  }
-
-  found = upb_inttable_lookup(&r->oneofs, index, &val);
-  UPB_ASSERT(found);
-  return upb_value_getptr(val);
-}
-
-/** Handlers for google.protobuf.FileDescriptorSet. ***************************/
-
-static void *fileset_startfile(void *closure, const void *hd) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-  r->file = upb_filedef_new(&r->files);
-  upb_inttable_push(&r->files, upb_value_ptr(r->file));
-  return r;
-}
-
-/** Handlers for google.protobuf.FileDescriptorProto. *************************/
-
-static bool file_start(void *closure, const void *hd) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-  upb_descreader_startcontainer(r);
-  return true;
-}
-
-static bool file_end(void *closure, const void *hd, upb_status *status) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-  UPB_UNUSED(status);
-  return upb_descreader_endcontainer(r);
-}
-
-static size_t file_onname(void *closure, const void *hd, const char *buf,
-                          size_t n, const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  char *name;
-  bool ok;
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-
-  name = upb_gstrndup(buf, n);
-  upb_strtable_insert(&r->files_by_name, name, upb_value_ptr(r->file));
-  /* XXX: see comment at the top of the file. */
-  ok = upb_filedef_setname(r->file, name, NULL);
-  upb_gfree(name);
-  UPB_ASSERT(ok);
-  return n;
-}
-
-static size_t file_onpackage(void *closure, const void *hd, const char *buf,
-                             size_t n, const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  char *package;
-  bool ok;
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-
-  package = upb_gstrndup(buf, n);
-  /* XXX: see comment at the top of the file. */
-  upb_descreader_setscopename(r, package);
-  ok = upb_filedef_setpackage(r->file, package, NULL);
-  UPB_ASSERT(ok);
-  return n;
-}
-
-static void *file_startphpnamespace(void *closure, const void *hd,
-                                    size_t size_hint) {
-  upb_descreader *r = closure;
-  bool ok;
-  UPB_UNUSED(hd);
-  UPB_UNUSED(size_hint);
-
-  ok = upb_filedef_setphpnamespace(r->file, "", NULL);
-  UPB_ASSERT(ok);
-  return closure;
-}
-
-static size_t file_onphpnamespace(void *closure, const void *hd,
-                                  const char *buf, size_t n,
-                                  const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  char *php_namespace;
-  bool ok;
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-
-  php_namespace = upb_gstrndup(buf, n);
-  ok = upb_filedef_setphpnamespace(r->file, php_namespace, NULL);
-  upb_gfree(php_namespace);
-  UPB_ASSERT(ok);
-  return n;
-}
-
-static size_t file_onphpprefix(void *closure, const void *hd, const char *buf,
-                             size_t n, const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  char *prefix;
-  bool ok;
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-
-  prefix = upb_gstrndup(buf, n);
-  ok = upb_filedef_setphpprefix(r->file, prefix, NULL);
-  upb_gfree(prefix);
-  UPB_ASSERT(ok);
-  return n;
-}
-
-static size_t file_onsyntax(void *closure, const void *hd, const char *buf,
-                            size_t n, const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  bool ok;
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-  /* XXX: see comment at the top of the file. */
-  if (upb_streq("proto2", buf, n)) {
-    ok = upb_filedef_setsyntax(r->file, UPB_SYNTAX_PROTO2, NULL);
-  } else if (upb_streq("proto3", buf, n)) {
-    ok = upb_filedef_setsyntax(r->file, UPB_SYNTAX_PROTO3, NULL);
-  } else {
-    ok = false;
-  }
-
-  UPB_ASSERT(ok);
-  return n;
-}
-
-static void *file_startmsg(void *closure, const void *hd) {
-  upb_descreader *r = closure;
-  upb_msgdef *m = upb_msgdef_new(&m);
-  bool ok = upb_filedef_addmsg(r->file, m, &m, NULL);
-  UPB_UNUSED(hd);
-  UPB_ASSERT(ok);
-  return r;
-}
-
-static void *file_startenum(void *closure, const void *hd) {
-  upb_descreader *r = closure;
-  upb_enumdef *e = upb_enumdef_new(&e);
-  bool ok = upb_filedef_addenum(r->file, e, &e, NULL);
-  UPB_UNUSED(hd);
-  UPB_ASSERT(ok);
-  return r;
-}
-
-static void *file_startext(void *closure, const void *hd) {
-  upb_descreader *r = closure;
-  bool ok;
-  r->f = upb_fielddef_new(r);
-  ok = upb_filedef_addext(r->file, r->f, r, NULL);
-  UPB_UNUSED(hd);
-  UPB_ASSERT(ok);
-  return r;
-}
-
-static size_t file_ondep(void *closure, const void *hd, const char *buf,
-                         size_t n, const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  upb_value val;
-  if (upb_strtable_lookup2(&r->files_by_name, buf, n, &val)) {
-    upb_filedef_adddep(r->file, upb_value_getptr(val));
-  }
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-  return n;
-}
-
-/** Handlers for google.protobuf.EnumValueDescriptorProto. *********************/
-
-static bool enumval_startmsg(void *closure, const void *hd) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-  r->saw_number = false;
-  r->saw_name = false;
-  return true;
-}
-
-static size_t enumval_onname(void *closure, const void *hd, const char *buf,
-                             size_t n, const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-  /* XXX: see comment at the top of the file. */
-  upb_gfree(r->name);
-  r->name = upb_gstrndup(buf, n);
-  r->saw_name = true;
-  return n;
-}
-
-static bool enumval_onnumber(void *closure, const void *hd, int32_t val) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-  r->number = val;
-  r->saw_number = true;
-  return true;
-}
-
-static bool enumval_endmsg(void *closure, const void *hd, upb_status *status) {
-  upb_descreader *r = closure;
-  upb_enumdef *e;
-  UPB_UNUSED(hd);
-
-  if(!r->saw_number || !r->saw_name) {
-    upb_status_seterrmsg(status, "Enum value missing name or number.");
-    return false;
-  }
-  e = upb_downcast_enumdef_mutable(upb_descreader_last(r));
-  upb_enumdef_addval(e, r->name, r->number, status);
-  upb_gfree(r->name);
-  r->name = NULL;
-  return true;
-}
-
-/** Handlers for google.protobuf.EnumDescriptorProto. *************************/
-
-static bool enum_endmsg(void *closure, const void *hd, upb_status *status) {
-  upb_descreader *r = closure;
-  upb_enumdef *e;
-  UPB_UNUSED(hd);
-
-  e = upb_downcast_enumdef_mutable(upb_descreader_last(r));
-  if (upb_def_fullname(upb_descreader_last(r)) == NULL) {
-    upb_status_seterrmsg(status, "Enum had no name.");
-    return false;
-  }
-  if (upb_enumdef_numvals(e) == 0) {
-    upb_status_seterrmsg(status, "Enum had no values.");
-    return false;
-  }
-  return true;
-}
-
-static size_t enum_onname(void *closure, const void *hd, const char *buf,
-                          size_t n, const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  char *fullname = upb_gstrndup(buf, n);
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-  /* XXX: see comment at the top of the file. */
-  upb_def_setfullname(upb_descreader_last(r), fullname, NULL);
-  upb_gfree(fullname);
-  return n;
-}
-
-/** Handlers for google.protobuf.FieldDescriptorProto *************************/
-
-static bool field_startmsg(void *closure, const void *hd) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-  UPB_ASSERT(r->f);
-  upb_gfree(r->default_string);
-  r->default_string = NULL;
-
-  /* fielddefs default to packed, but descriptors default to non-packed. */
-  upb_fielddef_setpacked(r->f, false);
-  return true;
-}
-
-/* Converts the default value in string "str" into "d".  Passes a ref on str.
- * Returns true on success. */
-static bool parse_default(char *str, upb_fielddef *f) {
-  bool success = true;
-  char *end;
-  switch (upb_fielddef_type(f)) {
-    case UPB_TYPE_INT32: {
-      long val = strtol(str, &end, 0);
-      if (val > INT32_MAX || val < INT32_MIN || errno == ERANGE || *end)
-        success = false;
-      else
-        upb_fielddef_setdefaultint32(f, val);
-      break;
-    }
-    case UPB_TYPE_INT64: {
-      /* XXX: Need to write our own strtoll, since it's not available in c89. */
-      long long val = strtol(str, &end, 0);
-      if (val > INT64_MAX || val < INT64_MIN || errno == ERANGE || *end)
-        success = false;
-      else
-        upb_fielddef_setdefaultint64(f, val);
-      break;
-    }
-    case UPB_TYPE_UINT32: {
-      unsigned long val = strtoul(str, &end, 0);
-      if (val > UINT32_MAX || errno == ERANGE || *end)
-        success = false;
-      else
-        upb_fielddef_setdefaultuint32(f, val);
-      break;
-    }
-    case UPB_TYPE_UINT64: {
-      /* XXX: Need to write our own strtoull, since it's not available in c89. */
-      unsigned long long val = strtoul(str, &end, 0);
-      if (val > UINT64_MAX || errno == ERANGE || *end)
-        success = false;
-      else
-        upb_fielddef_setdefaultuint64(f, val);
-      break;
-    }
-    case UPB_TYPE_DOUBLE: {
-      double val = strtod(str, &end);
-      if (errno == ERANGE || *end)
-        success = false;
-      else
-        upb_fielddef_setdefaultdouble(f, val);
-      break;
-    }
-    case UPB_TYPE_FLOAT: {
-      /* XXX: Need to write our own strtof, since it's not available in c89. */
-      float val = strtod(str, &end);
-      if (errno == ERANGE || *end)
-        success = false;
-      else
-        upb_fielddef_setdefaultfloat(f, val);
-      break;
-    }
-    case UPB_TYPE_BOOL: {
-      if (strcmp(str, "false") == 0)
-        upb_fielddef_setdefaultbool(f, false);
-      else if (strcmp(str, "true") == 0)
-        upb_fielddef_setdefaultbool(f, true);
-      else
-        success = false;
-      break;
-    }
-    default: abort();
-  }
-  return success;
-}
-
-static bool field_endmsg(void *closure, const void *hd, upb_status *status) {
-  upb_descreader *r = closure;
-  upb_fielddef *f = r->f;
-  UPB_UNUSED(hd);
-
-  /* TODO: verify that all required fields were present. */
-  UPB_ASSERT(upb_fielddef_number(f) != 0);
-  UPB_ASSERT(upb_fielddef_name(f) != NULL);
-  UPB_ASSERT((upb_fielddef_subdefname(f) != NULL) == upb_fielddef_hassubdef(f));
-
-  if (r->default_string) {
-    if (upb_fielddef_issubmsg(f)) {
-      upb_status_seterrmsg(status, "Submessages cannot have defaults.");
-      return false;
-    }
-    if (upb_fielddef_isstring(f) || upb_fielddef_type(f) == UPB_TYPE_ENUM) {
-      upb_fielddef_setdefaultcstr(f, r->default_string, NULL);
-    } else {
-      if (r->default_string && !parse_default(r->default_string, f)) {
-        /* We don't worry too much about giving a great error message since the
-         * compiler should have ensured this was correct. */
-        upb_status_seterrmsg(status, "Error converting default value.");
-        return false;
-      }
-    }
-  }
-  return true;
-}
-
-static bool field_onlazy(void *closure, const void *hd, bool val) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-
-  upb_fielddef_setlazy(r->f, val);
-  return true;
-}
-
-static bool field_onpacked(void *closure, const void *hd, bool val) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-
-  upb_fielddef_setpacked(r->f, val);
-  return true;
-}
-
-static bool field_ontype(void *closure, const void *hd, int32_t val) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-
-  upb_fielddef_setdescriptortype(r->f, val);
-  return true;
-}
-
-static bool field_onlabel(void *closure, const void *hd, int32_t val) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-
-  upb_fielddef_setlabel(r->f, val);
-  return true;
-}
-
-static bool field_onnumber(void *closure, const void *hd, int32_t val) {
-  upb_descreader *r = closure;
-  bool ok;
-  UPB_UNUSED(hd);
-
-  ok = upb_fielddef_setnumber(r->f, val, NULL);
-  UPB_ASSERT(ok);
-  return true;
-}
-
-static size_t field_onname(void *closure, const void *hd, const char *buf,
-                           size_t n, const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  char *name = upb_gstrndup(buf, n);
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-
-  /* XXX: see comment at the top of the file. */
-  upb_fielddef_setname(r->f, name, NULL);
-  upb_gfree(name);
-  return n;
-}
-
-static size_t field_ontypename(void *closure, const void *hd, const char *buf,
-                               size_t n, const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  char *name = upb_gstrndup(buf, n);
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-
-  /* XXX: see comment at the top of the file. */
-  upb_fielddef_setsubdefname(r->f, name, NULL);
-  upb_gfree(name);
-  return n;
-}
-
-static size_t field_onextendee(void *closure, const void *hd, const char *buf,
-                               size_t n, const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  char *name = upb_gstrndup(buf, n);
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-
-  /* XXX: see comment at the top of the file. */
-  upb_fielddef_setcontainingtypename(r->f, name, NULL);
-  upb_gfree(name);
-  return n;
-}
-
-static size_t field_ondefaultval(void *closure, const void *hd, const char *buf,
-                                 size_t n, const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-
-  /* Have to convert from string to the correct type, but we might not know the
-   * type yet, so we save it as a string until the end of the field.
-   * XXX: see comment at the top of the file. */
-  upb_gfree(r->default_string);
-  r->default_string = upb_gstrndup(buf, n);
-  return n;
-}
-
-static bool field_ononeofindex(void *closure, const void *hd, int32_t index) {
-  upb_descreader *r = closure;
-  upb_oneofdef *o = upb_descreader_getoneof(r, index);
-  bool ok = upb_oneofdef_addfield(o, r->f, &r->f, NULL);
-  UPB_UNUSED(hd);
-
-  UPB_ASSERT(ok);
-  return true;
-}
-
-/** Handlers for google.protobuf.OneofDescriptorProto. ************************/
-
-static size_t oneof_name(void *closure, const void *hd, const char *buf,
-                         size_t n, const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  upb_descreader_frame *f = &r->stack[r->stack_len-1];
-  upb_oneofdef *o = upb_descreader_getoneof(r, f->oneof_index++);
-  char *name_null_terminated = upb_gstrndup(buf, n);
-  bool ok = upb_oneofdef_setname(o, name_null_terminated, NULL);
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-
-  UPB_ASSERT(ok);
-  free(name_null_terminated);
-  return n;
-}
-
-/** Handlers for google.protobuf.DescriptorProto ******************************/
-
-static bool msg_start(void *closure, const void *hd) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-
-  upb_descreader_startcontainer(r);
-  return true;
-}
-
-static bool msg_end(void *closure, const void *hd, upb_status *status) {
-  upb_descreader *r = closure;
-  upb_msgdef *m = upb_descreader_top(r);
-  UPB_UNUSED(hd);
-
-  if(!upb_def_fullname(upb_msgdef_upcast_mutable(m))) {
-    upb_status_seterrmsg(status, "Encountered message with no name.");
-    return false;
-  }
-  return upb_descreader_endcontainer(r);
-}
-
-static size_t msg_name(void *closure, const void *hd, const char *buf,
-                       size_t n, const upb_bufhandle *handle) {
-  upb_descreader *r = closure;
-  upb_msgdef *m = upb_descreader_top(r);
-  /* XXX: see comment at the top of the file. */
-  char *name = upb_gstrndup(buf, n);
-  UPB_UNUSED(hd);
-  UPB_UNUSED(handle);
-
-  upb_def_setfullname(upb_msgdef_upcast_mutable(m), name, NULL);
-  upb_descreader_setscopename(r, name);  /* Passes ownership of name. */
-
-  return n;
-}
-
-static void *msg_startmsg(void *closure, const void *hd) {
-  upb_descreader *r = closure;
-  upb_msgdef *m = upb_msgdef_new(&m);
-  bool ok = upb_filedef_addmsg(r->file, m, &m, NULL);
-  UPB_UNUSED(hd);
-  UPB_ASSERT(ok);
-  return r;
-}
-
-static void *msg_startext(void *closure, const void *hd) {
-  upb_descreader *r = closure;
-  upb_fielddef *f = upb_fielddef_new(&f);
-  bool ok = upb_filedef_addext(r->file, f, &f, NULL);
-  UPB_UNUSED(hd);
-  UPB_ASSERT(ok);
-  return r;
-}
-
-static void *msg_startfield(void *closure, const void *hd) {
-  upb_descreader *r = closure;
-  r->f = upb_fielddef_new(&r->f);
-  /* We can't add the new field to the message until its name/number are
-   * filled in. */
-  UPB_UNUSED(hd);
-  return r;
-}
-
-static bool msg_endfield(void *closure, const void *hd) {
-  upb_descreader *r = closure;
-  upb_msgdef *m = upb_descreader_top(r);
-  bool ok;
-  UPB_UNUSED(hd);
-
-  /* Oneof fields are added to the msgdef through their oneof, so don't need to
-   * be added here. */
-  if (upb_fielddef_containingoneof(r->f) == NULL) {
-    ok = upb_msgdef_addfield(m, r->f, &r->f, NULL);
-    UPB_ASSERT(ok);
-  }
-  r->f = NULL;
-  return true;
-}
-
-static bool msg_onmapentry(void *closure, const void *hd, bool mapentry) {
-  upb_descreader *r = closure;
-  upb_msgdef *m = upb_descreader_top(r);
-  UPB_UNUSED(hd);
-
-  upb_msgdef_setmapentry(m, mapentry);
-  r->f = NULL;
-  return true;
-}
-
-
-
-/** Code to register handlers *************************************************/
-
-#define F(msg, field) upbdefs_google_protobuf_ ## msg ## _f_ ## field(m)
-
-static void reghandlers(const void *closure, upb_handlers *h) {
-  const upb_msgdef *m = upb_handlers_msgdef(h);
-  UPB_UNUSED(closure);
-
-  if (upbdefs_google_protobuf_FileDescriptorSet_is(m)) {
-    upb_handlers_setstartsubmsg(h, F(FileDescriptorSet, file),
-                                &fileset_startfile, NULL);
-  } else if (upbdefs_google_protobuf_DescriptorProto_is(m)) {
-    upb_handlers_setstartmsg(h, &msg_start, NULL);
-    upb_handlers_setendmsg(h, &msg_end, NULL);
-    upb_handlers_setstring(h, F(DescriptorProto, name), &msg_name, NULL);
-    upb_handlers_setstartsubmsg(h, F(DescriptorProto, extension), &msg_startext,
-                                NULL);
-    upb_handlers_setstartsubmsg(h, F(DescriptorProto, nested_type),
-                                &msg_startmsg, NULL);
-    upb_handlers_setstartsubmsg(h, F(DescriptorProto, field),
-                                &msg_startfield, NULL);
-    upb_handlers_setendsubmsg(h, F(DescriptorProto, field),
-                              &msg_endfield, NULL);
-    upb_handlers_setstartsubmsg(h, F(DescriptorProto, enum_type),
-                                &file_startenum, NULL);
-  } else if (upbdefs_google_protobuf_FileDescriptorProto_is(m)) {
-    upb_handlers_setstartmsg(h, &file_start, NULL);
-    upb_handlers_setendmsg(h, &file_end, NULL);
-    upb_handlers_setstring(h, F(FileDescriptorProto, name), &file_onname,
-                           NULL);
-    upb_handlers_setstring(h, F(FileDescriptorProto, package), &file_onpackage,
-                           NULL);
-    upb_handlers_setstring(h, F(FileDescriptorProto, syntax), &file_onsyntax,
-                           NULL);
-    upb_handlers_setstartsubmsg(h, F(FileDescriptorProto, message_type),
-                                &file_startmsg, NULL);
-    upb_handlers_setstartsubmsg(h, F(FileDescriptorProto, enum_type),
-                                &file_startenum, NULL);
-    upb_handlers_setstartsubmsg(h, F(FileDescriptorProto, extension),
-                                &file_startext, NULL);
-    upb_handlers_setstring(h, F(FileDescriptorProto, dependency),
-                           &file_ondep, NULL);
-  } else if (upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)) {
-    upb_handlers_setstartmsg(h, &enumval_startmsg, NULL);
-    upb_handlers_setendmsg(h, &enumval_endmsg, NULL);
-    upb_handlers_setstring(h, F(EnumValueDescriptorProto, name), &enumval_onname, NULL);
-    upb_handlers_setint32(h, F(EnumValueDescriptorProto, number), &enumval_onnumber,
-                          NULL);
-  } else if (upbdefs_google_protobuf_EnumDescriptorProto_is(m)) {
-    upb_handlers_setendmsg(h, &enum_endmsg, NULL);
-    upb_handlers_setstring(h, F(EnumDescriptorProto, name), &enum_onname, NULL);
-  } else if (upbdefs_google_protobuf_FieldDescriptorProto_is(m)) {
-    upb_handlers_setstartmsg(h, &field_startmsg, NULL);
-    upb_handlers_setendmsg(h, &field_endmsg, NULL);
-    upb_handlers_setint32(h, F(FieldDescriptorProto, type), &field_ontype,
-                          NULL);
-    upb_handlers_setint32(h, F(FieldDescriptorProto, label), &field_onlabel,
-                          NULL);
-    upb_handlers_setint32(h, F(FieldDescriptorProto, number), &field_onnumber,
-                          NULL);
-    upb_handlers_setstring(h, F(FieldDescriptorProto, name), &field_onname,
-                           NULL);
-    upb_handlers_setstring(h, F(FieldDescriptorProto, type_name),
-                           &field_ontypename, NULL);
-    upb_handlers_setstring(h, F(FieldDescriptorProto, extendee),
-                           &field_onextendee, NULL);
-    upb_handlers_setstring(h, F(FieldDescriptorProto, default_value),
-                           &field_ondefaultval, NULL);
-    upb_handlers_setint32(h, F(FieldDescriptorProto, oneof_index),
-                          &field_ononeofindex, NULL);
-  } else if (upbdefs_google_protobuf_OneofDescriptorProto_is(m)) {
-    upb_handlers_setstring(h, F(OneofDescriptorProto, name), &oneof_name, NULL);
-  } else if (upbdefs_google_protobuf_FieldOptions_is(m)) {
-    upb_handlers_setbool(h, F(FieldOptions, lazy), &field_onlazy, NULL);
-    upb_handlers_setbool(h, F(FieldOptions, packed), &field_onpacked, NULL);
-  } else if (upbdefs_google_protobuf_MessageOptions_is(m)) {
-    upb_handlers_setbool(h, F(MessageOptions, map_entry), &msg_onmapentry, NULL);
-  } else if (upbdefs_google_protobuf_FileOptions_is(m)) {
-    upb_handlers_setstring(h, F(FileOptions, php_class_prefix),
-                           &file_onphpprefix, NULL);
-    upb_handlers_setstartstr(h, F(FileOptions, php_namespace),
-                             &file_startphpnamespace, NULL);
-    upb_handlers_setstring(h, F(FileOptions, php_namespace),
-                           &file_onphpnamespace, NULL);
-  }
-
-  UPB_ASSERT(upb_ok(upb_handlers_status(h)));
-}
-
-#undef F
-
-void descreader_cleanup(void *_r) {
-  upb_descreader *r = _r;
-  size_t i;
-
-  for (i = 0; i < upb_descreader_filecount(r); i++) {
-    upb_filedef_unref(upb_descreader_file(r, i), &r->files);
-  }
-
-  upb_gfree(r->name);
-  upb_inttable_uninit(&r->files);
-  upb_strtable_uninit(&r->files_by_name);
-  upb_inttable_uninit(&r->oneofs);
-  upb_gfree(r->default_string);
-  while (r->stack_len > 0) {
-    upb_descreader_frame *f = &r->stack[--r->stack_len];
-    upb_gfree(f->name);
-  }
-}
-
-
-/* Public API  ****************************************************************/
-
-upb_descreader *upb_descreader_create(upb_env *e, const upb_handlers *h) {
-  upb_descreader *r = upb_env_malloc(e, sizeof(upb_descreader));
-  if (!r || !upb_env_addcleanup(e, descreader_cleanup, r)) {
-    return NULL;
-  }
-
-  upb_inttable_init(&r->files, UPB_CTYPE_PTR);
-  upb_strtable_init(&r->files_by_name, UPB_CTYPE_PTR);
-  upb_inttable_init(&r->oneofs, UPB_CTYPE_PTR);
-  upb_sink_reset(upb_descreader_input(r), h, r);
-  r->stack_len = 0;
-  r->name = NULL;
-  r->default_string = NULL;
-
-  return r;
-}
-
-size_t upb_descreader_filecount(const upb_descreader *r) {
-  return upb_inttable_count(&r->files);
-}
-
-upb_filedef *upb_descreader_file(const upb_descreader *r, size_t i) {
-  upb_value v;
-  if (upb_inttable_lookup(&r->files, i, &v)) {
-    return upb_value_getptr(v);
-  } else {
-    return NULL;
-  }
-}
-
-upb_sink *upb_descreader_input(upb_descreader *r) {
-  return &r->sink;
-}
-
-const upb_handlers *upb_descreader_newhandlers(const void *owner) {
-  const upb_msgdef *m = upbdefs_google_protobuf_FileDescriptorSet_get(&m);
-  const upb_handlers *h = upb_handlers_newfrozen(m, owner, reghandlers, NULL);
-  upb_msgdef_unref(m, &m);
-  return h;
-}
 /*
 ** protobuf decoder bytecode compiler
 **
 ** Code to compile a upb::Handlers into bytecode for decoding a protobuf
 ** according to that specific schema and destination handlers.
 **
-** Compiling to bytecode is always the first step.  If we are using the
-** interpreted decoder we leave it as bytecode and interpret that.  If we are
-** using a JIT decoder we use a code generator to turn the bytecode into native
-** code, LLVM IR, etc.
-**
 ** Bytecode definition is in decoder.int.h.
 */
 
@@ -9501,80 +5816,22 @@
 #define MAXLABEL 5
 #define EMPTYLABEL -1
 
-/* mgroup *********************************************************************/
-
-static void freegroup(upb_refcounted *r) {
-  mgroup *g = (mgroup*)r;
-  upb_inttable_uninit(&g->methods);
-#ifdef UPB_USE_JIT_X64
-  upb_pbdecoder_freejit(g);
-#endif
-  upb_gfree(g->bytecode);
-  upb_gfree(g);
-}
-
-static void visitgroup(const upb_refcounted *r, upb_refcounted_visit *visit,
-                       void *closure) {
-  const mgroup *g = (const mgroup*)r;
-  upb_inttable_iter i;
-  upb_inttable_begin(&i, &g->methods);
-  for(; !upb_inttable_done(&i); upb_inttable_next(&i)) {
-    upb_pbdecodermethod *method = upb_value_getptr(upb_inttable_iter_value(&i));
-    visit(r, upb_pbdecodermethod_upcast(method), closure);
-  }
-}
-
-mgroup *newgroup(const void *owner) {
-  mgroup *g = upb_gmalloc(sizeof(*g));
-  static const struct upb_refcounted_vtbl vtbl = {visitgroup, freegroup};
-  upb_refcounted_init(mgroup_upcast_mutable(g), &vtbl, owner);
-  upb_inttable_init(&g->methods, UPB_CTYPE_PTR);
-  g->bytecode = NULL;
-  g->bytecode_end = NULL;
-  return g;
-}
-
-
 /* upb_pbdecodermethod ********************************************************/
 
-static void freemethod(upb_refcounted *r) {
-  upb_pbdecodermethod *method = (upb_pbdecodermethod*)r;
-
-  if (method->dest_handlers_) {
-    upb_handlers_unref(method->dest_handlers_, method);
-  }
-
+static void freemethod(upb_pbdecodermethod *method) {
   upb_inttable_uninit(&method->dispatch);
   upb_gfree(method);
 }
 
-static void visitmethod(const upb_refcounted *r, upb_refcounted_visit *visit,
-                        void *closure) {
-  const upb_pbdecodermethod *m = (const upb_pbdecodermethod*)r;
-  visit(r, m->group, closure);
-}
-
 static upb_pbdecodermethod *newmethod(const upb_handlers *dest_handlers,
                                       mgroup *group) {
-  static const struct upb_refcounted_vtbl vtbl = {visitmethod, freemethod};
   upb_pbdecodermethod *ret = upb_gmalloc(sizeof(*ret));
-  upb_refcounted_init(upb_pbdecodermethod_upcast_mutable(ret), &vtbl, &ret);
   upb_byteshandler_init(&ret->input_handler_);
 
-  /* The method references the group and vice-versa, in a circular reference. */
-  upb_ref2(ret, group);
-  upb_ref2(group, ret);
-  upb_inttable_insertptr(&group->methods, dest_handlers, upb_value_ptr(ret));
-  upb_pbdecodermethod_unref(ret, &ret);
-
-  ret->group = mgroup_upcast_mutable(group);
+  ret->group = group;
   ret->dest_handlers_ = dest_handlers;
-  ret->is_native_ = false;  /* If we JIT, it will update this later. */
   upb_inttable_init(&ret->dispatch, UPB_CTYPE_UINT64);
 
-  if (ret->dest_handlers_) {
-    upb_handlers_ref(ret->dest_handlers_, ret);
-  }
   return ret;
 }
 
@@ -9592,16 +5849,28 @@
   return m->is_native_;
 }
 
-const upb_pbdecodermethod *upb_pbdecodermethod_new(
-    const upb_pbdecodermethodopts *opts, const void *owner) {
-  const upb_pbdecodermethod *ret;
-  upb_pbcodecache cache;
 
-  upb_pbcodecache_init(&cache);
-  ret = upb_pbcodecache_getdecodermethod(&cache, opts);
-  upb_pbdecodermethod_ref(ret, owner);
-  upb_pbcodecache_uninit(&cache);
-  return ret;
+/* mgroup *********************************************************************/
+
+static void freegroup(mgroup *g) {
+  upb_inttable_iter i;
+
+  upb_inttable_begin(&i, &g->methods);
+  for(; !upb_inttable_done(&i); upb_inttable_next(&i)) {
+    freemethod(upb_value_getptr(upb_inttable_iter_value(&i)));
+  }
+
+  upb_inttable_uninit(&g->methods);
+  upb_gfree(g->bytecode);
+  upb_gfree(g);
+}
+
+mgroup *newgroup() {
+  mgroup *g = upb_gmalloc(sizeof(*g));
+  upb_inttable_init(&g->methods, UPB_CTYPE_PTR);
+  g->bytecode = NULL;
+  g->bytecode_end = NULL;
+  return g;
 }
 
 
@@ -9833,7 +6102,7 @@
   va_end(ap);
 }
 
-#if defined(UPB_USE_JIT_X64) || defined(UPB_DUMP_BYTECODE)
+#if defined(UPB_DUMP_BYTECODE)
 
 const char *upb_pbdecoder_getopname(unsigned int op) {
 #define QUOTE(x) #x
@@ -10036,7 +6305,7 @@
 
 static void putsel(compiler *c, opcode op, upb_selector_t sel,
                    const upb_handlers *h) {
-  if (upb_handlers_gethandler(h, sel)) {
+  if (upb_handlers_gethandler(h, sel, NULL)) {
     putop(c, op, sel);
   }
 }
@@ -10052,9 +6321,9 @@
   if (!upb_fielddef_lazy(f))
     return false;
 
-  return upb_handlers_gethandler(h, getsel(f, UPB_HANDLER_STARTSTR)) ||
-         upb_handlers_gethandler(h, getsel(f, UPB_HANDLER_STRING)) ||
-         upb_handlers_gethandler(h, getsel(f, UPB_HANDLER_ENDSTR));
+  return upb_handlers_gethandler(h, getsel(f, UPB_HANDLER_STARTSTR), NULL) ||
+         upb_handlers_gethandler(h, getsel(f, UPB_HANDLER_STRING), NULL) ||
+         upb_handlers_gethandler(h, getsel(f, UPB_HANDLER_ENDSTR), NULL);
 }
 
 
@@ -10292,10 +6561,13 @@
   upb_value v;
   upb_msg_field_iter i;
   const upb_msgdef *md;
+  upb_pbdecodermethod *method;
 
   if (upb_inttable_lookupptr(&c->group->methods, h, &v))
     return;
-  newmethod(h, c->group);
+
+  method = newmethod(h, c->group);
+  upb_inttable_insertptr(&c->group->methods, h, upb_value_ptr(method));
 
   /* Find submethods. */
   md = upb_handlers_msgdef(h);
@@ -10344,42 +6616,15 @@
 }
 
 
-/* JIT setup. *****************************************************************/
-
-#ifdef UPB_USE_JIT_X64
-
-static void sethandlers(mgroup *g, bool allowjit) {
-  g->jit_code = NULL;
-  if (allowjit) {
-    /* Compile byte-code into machine code, create handlers. */
-    upb_pbdecoder_jit(g);
-  } else {
-    set_bytecode_handlers(g);
-  }
-}
-
-#else  /* UPB_USE_JIT_X64 */
-
-static void sethandlers(mgroup *g, bool allowjit) {
-  /* No JIT compiled in; use bytecode handlers unconditionally. */
-  UPB_UNUSED(allowjit);
-  set_bytecode_handlers(g);
-}
-
-#endif  /* UPB_USE_JIT_X64 */
-
-
 /* TODO(haberman): allow this to be constructed for an arbitrary set of dest
  * handlers and other mgroups (but verify we have a transitive closure). */
-const mgroup *mgroup_new(const upb_handlers *dest, bool allowjit, bool lazy,
-                         const void *owner) {
+const mgroup *mgroup_new(const upb_handlers *dest, bool allowjit, bool lazy) {
   mgroup *g;
   compiler *c;
 
   UPB_UNUSED(allowjit);
-  UPB_ASSERT(upb_handlers_isfrozen(dest));
 
-  g = newgroup(owner);
+  g = newgroup();
   c = newcompiler(g, lazy);
   find_methods(c, dest);
 
@@ -10410,66 +6655,74 @@
   }
 #endif
 
-  sethandlers(g, allowjit);
+  set_bytecode_handlers(g);
   return g;
 }
 
 
 /* upb_pbcodecache ************************************************************/
 
-void upb_pbcodecache_init(upb_pbcodecache *c) {
-  upb_inttable_init(&c->groups, UPB_CTYPE_CONSTPTR);
-  c->allow_jit_ = true;
+upb_pbcodecache *upb_pbcodecache_new(upb_handlercache *dest) {
+  upb_pbcodecache *c = upb_gmalloc(sizeof(*c));
+
+  if (!c) return NULL;
+
+  c->dest = dest;
+  c->allow_jit = true;
+  c->lazy = false;
+
+  c->arena = upb_arena_new();
+  if (!upb_inttable_init(&c->groups, UPB_CTYPE_CONSTPTR)) return NULL;
+
+  return c;
 }
 
-void upb_pbcodecache_uninit(upb_pbcodecache *c) {
-  upb_inttable_iter i;
-  upb_inttable_begin(&i, &c->groups);
-  for(; !upb_inttable_done(&i); upb_inttable_next(&i)) {
-    const mgroup *group = upb_value_getconstptr(upb_inttable_iter_value(&i));
-    mgroup_unref(group, c);
+void upb_pbcodecache_free(upb_pbcodecache *c) {
+  size_t i;
+
+  for (i = 0; i < upb_inttable_count(&c->groups); i++) {
+    upb_value v;
+    bool ok = upb_inttable_lookup(&c->groups, i, &v);
+    UPB_ASSERT(ok);
+    freegroup((void*)upb_value_getconstptr(v));
   }
+
   upb_inttable_uninit(&c->groups);
+  upb_arena_free(c->arena);
+  upb_gfree(c);
 }
 
 bool upb_pbcodecache_allowjit(const upb_pbcodecache *c) {
-  return c->allow_jit_;
+  return c->allow_jit;
 }
 
-bool upb_pbcodecache_setallowjit(upb_pbcodecache *c, bool allow) {
-  if (upb_inttable_count(&c->groups) > 0)
-    return false;
-  c->allow_jit_ = allow;
-  return true;
+void upb_pbcodecache_setallowjit(upb_pbcodecache *c, bool allow) {
+  UPB_ASSERT(upb_inttable_count(&c->groups) == 0);
+  c->allow_jit = allow;
 }
 
-const upb_pbdecodermethod *upb_pbcodecache_getdecodermethod(
-    upb_pbcodecache *c, const upb_pbdecodermethodopts *opts) {
+void upb_pbdecodermethodopts_setlazy(upb_pbcodecache *c, bool lazy) {
+  UPB_ASSERT(upb_inttable_count(&c->groups) == 0);
+  c->lazy = lazy;
+}
+
+const upb_pbdecodermethod *upb_pbcodecache_get(upb_pbcodecache *c,
+                                               const upb_msgdef *md) {
   upb_value v;
   bool ok;
+  const upb_handlers *h;
+  const mgroup *g;
 
   /* Right now we build a new DecoderMethod every time.
    * TODO(haberman): properly cache methods by their true key. */
-  const mgroup *g = mgroup_new(opts->handlers, c->allow_jit_, opts->lazy, c);
+  h = upb_handlercache_get(c->dest, md);
+  g = mgroup_new(h, c->allow_jit, c->lazy);
   upb_inttable_push(&c->groups, upb_value_constptr(g));
 
-  ok = upb_inttable_lookupptr(&g->methods, opts->handlers, &v);
+  ok = upb_inttable_lookupptr(&g->methods, h, &v);
   UPB_ASSERT(ok);
   return upb_value_getptr(v);
 }
-
-
-/* upb_pbdecodermethodopts ****************************************************/
-
-void upb_pbdecodermethodopts_init(upb_pbdecodermethodopts *opts,
-                                  const upb_handlers *h) {
-  opts->handlers = h;
-  opts->lazy = false;
-}
-
-void upb_pbdecodermethodopts_setlazy(upb_pbdecodermethodopts *opts, bool lazy) {
-  opts->lazy = lazy;
-}
 /*
 ** upb::Decoder (Bytecode Decoder VM)
 **
@@ -10569,9 +6822,7 @@
  * benchmarks. */
 
 static void seterr(upb_pbdecoder *d, const char *msg) {
-  upb_status status = UPB_STATUS_INIT;
-  upb_status_seterrmsg(&status, msg);
-  upb_env_reporterror(d->env, &status);
+  upb_status_seterrmsg(d->status, msg);
 }
 
 void upb_pbdecoder_seterr(upb_pbdecoder *d, const char *msg) {
@@ -11066,7 +7317,7 @@
 
     if (d->top->groupnum >= 0) {
       /* TODO: More code needed for handling unknown groups. */
-      upb_sink_putunknown(&d->top->sink, d->checkpoint, d->ptr - d->checkpoint);
+      upb_sink_putunknown(d->top->sink, d->checkpoint, d->ptr - d->checkpoint);
       return DECODE_OK;
     }
 
@@ -11160,7 +7411,7 @@
   VMCASE(OP_PARSE_ ## type, { \
     ctype val; \
     CHECK_RETURN(decode_ ## wt(d, &val)); \
-    upb_sink_put ## name(&d->top->sink, arg, (convfunc)(val)); \
+    upb_sink_put ## name(d->top->sink, arg, (convfunc)(val)); \
   })
 
   while(1) {
@@ -11212,36 +7463,36 @@
         d->pc += sizeof(void*) / sizeof(uint32_t);
       )
       VMCASE(OP_STARTMSG,
-        CHECK_SUSPEND(upb_sink_startmsg(&d->top->sink));
+        CHECK_SUSPEND(upb_sink_startmsg(d->top->sink));
       )
       VMCASE(OP_ENDMSG,
-        CHECK_SUSPEND(upb_sink_endmsg(&d->top->sink, d->status));
+        CHECK_SUSPEND(upb_sink_endmsg(d->top->sink, d->status));
       )
       VMCASE(OP_STARTSEQ,
         upb_pbdecoder_frame *outer = outer_frame(d);
-        CHECK_SUSPEND(upb_sink_startseq(&outer->sink, arg, &d->top->sink));
+        CHECK_SUSPEND(upb_sink_startseq(outer->sink, arg, &d->top->sink));
       )
       VMCASE(OP_ENDSEQ,
-        CHECK_SUSPEND(upb_sink_endseq(&d->top->sink, arg));
+        CHECK_SUSPEND(upb_sink_endseq(d->top->sink, arg));
       )
       VMCASE(OP_STARTSUBMSG,
         upb_pbdecoder_frame *outer = outer_frame(d);
-        CHECK_SUSPEND(upb_sink_startsubmsg(&outer->sink, arg, &d->top->sink));
+        CHECK_SUSPEND(upb_sink_startsubmsg(outer->sink, arg, &d->top->sink));
       )
       VMCASE(OP_ENDSUBMSG,
-        CHECK_SUSPEND(upb_sink_endsubmsg(&d->top->sink, arg));
+        CHECK_SUSPEND(upb_sink_endsubmsg(d->top->sink, arg));
       )
       VMCASE(OP_STARTSTR,
         uint32_t len = delim_remaining(d);
         upb_pbdecoder_frame *outer = outer_frame(d);
-        CHECK_SUSPEND(upb_sink_startstr(&outer->sink, arg, len, &d->top->sink));
+        CHECK_SUSPEND(upb_sink_startstr(outer->sink, arg, len, &d->top->sink));
         if (len == 0) {
           d->pc++;  /* Skip OP_STRING. */
         }
       )
       VMCASE(OP_STRING,
         uint32_t len = curbufleft(d);
-        size_t n = upb_sink_putstring(&d->top->sink, arg, d->ptr, len, handle);
+        size_t n = upb_sink_putstring(d->top->sink, arg, d->ptr, len, handle);
         if (n > len) {
           if (n > delim_remaining(d)) {
             seterr(d, "Tried to skip past end of string.");
@@ -11262,7 +7513,7 @@
         }
       )
       VMCASE(OP_ENDSTR,
-        CHECK_SUSPEND(upb_sink_endstr(&d->top->sink, arg));
+        CHECK_SUSPEND(upb_sink_endstr(d->top->sink, arg));
       )
       VMCASE(OP_PUSHTAGDELIM,
         CHECK_SUSPEND(pushtagdelim(d, arg));
@@ -11462,40 +7713,39 @@
   d->residual_end = d->residual;
 }
 
-upb_pbdecoder *upb_pbdecoder_create(upb_env *e, const upb_pbdecodermethod *m,
-                                    upb_sink *sink) {
+upb_pbdecoder *upb_pbdecoder_create(upb_arena *a, const upb_pbdecodermethod *m,
+                                    upb_sink sink, upb_status *status) {
   const size_t default_max_nesting = 64;
 #ifndef NDEBUG
-  size_t size_before = upb_env_bytesallocated(e);
+  size_t size_before = upb_arena_bytesallocated(a);
 #endif
 
-  upb_pbdecoder *d = upb_env_malloc(e, sizeof(upb_pbdecoder));
+  upb_pbdecoder *d = upb_arena_malloc(a, sizeof(upb_pbdecoder));
   if (!d) return NULL;
 
   d->method_ = m;
-  d->callstack = upb_env_malloc(e, callstacksize(d, default_max_nesting));
-  d->stack = upb_env_malloc(e, stacksize(d, default_max_nesting));
+  d->callstack = upb_arena_malloc(a, callstacksize(d, default_max_nesting));
+  d->stack = upb_arena_malloc(a, stacksize(d, default_max_nesting));
   if (!d->stack || !d->callstack) {
     return NULL;
   }
 
-  d->env = e;
+  d->arena = a;
   d->limit = d->stack + default_max_nesting - 1;
   d->stack_size = default_max_nesting;
-  d->status = NULL;
+  d->status = status;
 
   upb_pbdecoder_reset(d);
   upb_bytessink_reset(&d->input_, &m->input_handler_, d);
 
-  UPB_ASSERT(sink);
   if (d->method_->dest_handlers_) {
-    if (sink->handlers != d->method_->dest_handlers_)
+    if (sink.handlers != d->method_->dest_handlers_)
       return NULL;
   }
-  upb_sink_reset(&d->top->sink, sink->handlers, sink->closure);
+  d->top->sink = sink;
 
   /* If this fails, increase the value in decoder.h. */
-  UPB_ASSERT_DEBUGVAR(upb_env_bytesallocated(e) - size_before <=
+  UPB_ASSERT_DEBUGVAR(upb_arena_bytesallocated(a) - size_before <=
                       UPB_PB_DECODER_SIZE);
   return d;
 }
@@ -11508,8 +7758,8 @@
   return d->method_;
 }
 
-upb_bytessink *upb_pbdecoder_input(upb_pbdecoder *d) {
-  return &d->input_;
+upb_bytessink upb_pbdecoder_input(upb_pbdecoder *d) {
+  return d->input_;
 }
 
 size_t upb_pbdecoder_maxnesting(const upb_pbdecoder *d) {
@@ -11528,7 +7778,7 @@
     /* Need to reallocate stack and callstack to accommodate. */
     size_t old_size = stacksize(d, d->stack_size);
     size_t new_size = stacksize(d, max);
-    void *p = upb_env_realloc(d->env, d->stack, old_size, new_size);
+    void *p = upb_arena_realloc(d->arena, d->stack, old_size, new_size);
     if (!p) {
       return false;
     }
@@ -11536,7 +7786,7 @@
 
     old_size = callstacksize(d, d->stack_size);
     new_size = callstacksize(d, max);
-    p = upb_env_realloc(d->env, d->callstack, old_size, new_size);
+    p = upb_arena_realloc(d->arena, d->callstack, old_size, new_size);
     if (!p) {
       return false;
     }
@@ -11639,11 +7889,11 @@
 } upb_pb_encoder_segment;
 
 struct upb_pb_encoder {
-  upb_env *env;
+  upb_arena *arena;
 
   /* Our input and output. */
   upb_sink input_;
-  upb_bytessink *output_;
+  upb_bytessink output_;
 
   /* The "subclosure" -- used as the inner closure as part of the bytessink
    * protocol. */
@@ -11698,7 +7948,7 @@
       new_size *= 2;
     }
 
-    new_buf = upb_env_realloc(e->env, e->buf, old_size, new_size);
+    new_buf = upb_arena_realloc(e->arena, e->buf, old_size, new_size);
 
     if (new_buf == NULL) {
       return false;
@@ -11778,7 +8028,7 @@
           (e->seglimit - e->segbuf) * sizeof(upb_pb_encoder_segment);
       size_t new_size = old_size * 2;
       upb_pb_encoder_segment *new_buf =
-          upb_env_realloc(e->env, e->segbuf, old_size, new_size);
+          upb_arena_realloc(e->arena, e->segbuf, old_size, new_size);
 
       if (new_buf == NULL) {
         return false;
@@ -11852,8 +8102,7 @@
   tag_t *tag = upb_gmalloc(sizeof(tag_t));
   tag->bytes = upb_vencode64((n << 3) | wt, tag->tag);
 
-  upb_handlerattr_init(attr);
-  upb_handlerattr_sethandlerdata(attr, tag);
+  attr->handler_data = tag;
   upb_handlers_addcleanup(h, tag, upb_gfree);
 }
 
@@ -11982,6 +8231,7 @@
 
 /* code to build the handlers *************************************************/
 
+#include <stdio.h>
 static void newhandlers_callback(const void *closure, upb_handlers *h) {
   const upb_msgdef *m;
   upb_msg_field_iter i;
@@ -11999,7 +8249,7 @@
     const upb_fielddef *f = upb_msg_iter_field(&i);
     bool packed = upb_fielddef_isseq(f) && upb_fielddef_isprimitive(f) &&
                   upb_fielddef_packed(f);
-    upb_handlerattr attr;
+    upb_handlerattr attr = UPB_HANDLERATTR_INIT;
     upb_wiretype_t wt =
         packed ? UPB_WIRE_TYPE_DELIMITED
                : upb_pb_native_wire_types[upb_fielddef_descriptortype(f)];
@@ -12048,20 +8298,17 @@
         break;
       case UPB_DESCRIPTOR_TYPE_GROUP: {
         /* Endgroup takes a different tag (wire_type = END_GROUP). */
-        upb_handlerattr attr2;
+        upb_handlerattr attr2 = UPB_HANDLERATTR_INIT;
         new_tag(h, f, UPB_WIRE_TYPE_END_GROUP, &attr2);
 
         upb_handlers_setstartsubmsg(h, f, encode_startgroup, &attr);
         upb_handlers_setendsubmsg(h, f, encode_endgroup, &attr2);
 
-        upb_handlerattr_uninit(&attr2);
         break;
       }
     }
 
 #undef T
-
-    upb_handlerattr_uninit(&attr);
   }
 }
 
@@ -12074,27 +8321,26 @@
 
 /* public API *****************************************************************/
 
-const upb_handlers *upb_pb_encoder_newhandlers(const upb_msgdef *m,
-                                               const void *owner) {
-  return upb_handlers_newfrozen(m, owner, newhandlers_callback, NULL);
+upb_handlercache *upb_pb_encoder_newcache() {
+  return upb_handlercache_new(newhandlers_callback, NULL);
 }
 
-upb_pb_encoder *upb_pb_encoder_create(upb_env *env, const upb_handlers *h,
-                                      upb_bytessink *output) {
+upb_pb_encoder *upb_pb_encoder_create(upb_arena *arena, const upb_handlers *h,
+                                      upb_bytessink output) {
   const size_t initial_bufsize = 256;
   const size_t initial_segbufsize = 16;
   /* TODO(haberman): make this configurable. */
   const size_t stack_size = 64;
 #ifndef NDEBUG
-  const size_t size_before = upb_env_bytesallocated(env);
+  const size_t size_before = upb_arena_bytesallocated(arena);
 #endif
 
-  upb_pb_encoder *e = upb_env_malloc(env, sizeof(upb_pb_encoder));
+  upb_pb_encoder *e = upb_arena_malloc(arena, sizeof(upb_pb_encoder));
   if (!e) return NULL;
 
-  e->buf = upb_env_malloc(env, initial_bufsize);
-  e->segbuf = upb_env_malloc(env, initial_segbufsize * sizeof(*e->segbuf));
-  e->stack = upb_env_malloc(env, stack_size * sizeof(*e->stack));
+  e->buf = upb_arena_malloc(arena, initial_bufsize);
+  e->segbuf = upb_arena_malloc(arena, initial_segbufsize * sizeof(*e->segbuf));
+  e->stack = upb_arena_malloc(arena, stack_size * sizeof(*e->stack));
 
   if (!e->buf || !e->segbuf || !e->stack) {
     return NULL;
@@ -12107,69 +8353,18 @@
   upb_pb_encoder_reset(e);
   upb_sink_reset(&e->input_, h, e);
 
-  e->env = env;
+  e->arena = arena;
   e->output_ = output;
-  e->subc = output->closure;
+  e->subc = output.closure;
   e->ptr = e->buf;
 
   /* If this fails, increase the value in encoder.h. */
-  UPB_ASSERT_DEBUGVAR(upb_env_bytesallocated(env) - size_before <=
+  UPB_ASSERT_DEBUGVAR(upb_arena_bytesallocated(arena) - size_before <=
                       UPB_PB_ENCODER_SIZE);
   return e;
 }
 
-upb_sink *upb_pb_encoder_input(upb_pb_encoder *e) { return &e->input_; }
-
-
-
-upb_filedef **upb_loaddescriptor(const char *buf, size_t n, const void *owner,
-                                 upb_status *status) {
-  /* Create handlers. */
-  const upb_pbdecodermethod *decoder_m;
-  const upb_handlers *reader_h = upb_descreader_newhandlers(&reader_h);
-  upb_env env;
-  upb_pbdecodermethodopts opts;
-  upb_pbdecoder *decoder;
-  upb_descreader *reader;
-  bool ok;
-  size_t i;
-  upb_filedef **ret = NULL;
-
-  upb_pbdecodermethodopts_init(&opts, reader_h);
-  decoder_m = upb_pbdecodermethod_new(&opts, &decoder_m);
-
-  upb_env_init(&env);
-  upb_env_reporterrorsto(&env, status);
-
-  reader = upb_descreader_create(&env, reader_h);
-  decoder = upb_pbdecoder_create(&env, decoder_m, upb_descreader_input(reader));
-
-  /* Push input data. */
-  ok = upb_bufsrc_putbuf(buf, n, upb_pbdecoder_input(decoder));
-
-  if (!ok) {
-    goto cleanup;
-  }
-
-  ret = upb_gmalloc(sizeof (*ret) * (upb_descreader_filecount(reader) + 1));
-
-  if (!ret) {
-    goto cleanup;
-  }
-
-  for (i = 0; i < upb_descreader_filecount(reader); i++) {
-    ret[i] = upb_descreader_file(reader, i);
-    upb_filedef_ref(ret[i], owner);
-  }
-
-  ret[i] = NULL;
-
-cleanup:
-  upb_env_uninit(&env);
-  upb_handlers_unref(reader_h, &reader_h);
-  upb_pbdecodermethod_unref(decoder_m, &decoder_m);
-  return ret;
-}
+upb_sink upb_pb_encoder_input(upb_pb_encoder *e) { return e->input_; }
 /*
  * upb::pb::TextPrinter
  *
@@ -12188,7 +8383,7 @@
 
 struct upb_textprinter {
   upb_sink input_;
-  upb_bytessink *output_;
+  upb_bytessink output_;
   int indent_depth_;
   bool single_line_;
   void *subc;
@@ -12353,7 +8548,7 @@
                                 int32_t val) {
   upb_textprinter *p = closure;
   const upb_fielddef *f = handler_data;
-  const upb_enumdef *enum_def = upb_downcast_enumdef(upb_fielddef_subdef(f));
+  const upb_enumdef *enum_def = upb_fielddef_enumsubdef(f);
   const char *label = upb_enumdef_iton(enum_def, val);
   if (label) {
     indent(p);
@@ -12430,8 +8625,8 @@
       !upb_msg_field_done(&i);
       upb_msg_field_next(&i)) {
     upb_fielddef *f = upb_msg_iter_field(&i);
-    upb_handlerattr attr = UPB_HANDLERATTR_INITIALIZER;
-    upb_handlerattr_sethandlerdata(&attr, f);
+    upb_handlerattr attr = UPB_HANDLERATTR_INIT;
+    attr.handler_data = f;
     switch (upb_fielddef_type(f)) {
       case UPB_TYPE_INT32:
         upb_handlers_setint32(h, f, textprinter_putint32, &attr);
@@ -12462,10 +8657,10 @@
         break;
       case UPB_TYPE_MESSAGE: {
         const char *name =
-            upb_fielddef_istagdelim(f)
+            upb_fielddef_descriptortype(f) == UPB_DESCRIPTOR_TYPE_GROUP
                 ? shortname(upb_msgdef_fullname(upb_fielddef_msgsubdef(f)))
                 : upb_fielddef_name(f);
-        upb_handlerattr_sethandlerdata(&attr, name);
+        attr.handler_data = name;
         upb_handlers_setstartsubmsg(h, f, textprinter_startsubmsg, &attr);
         upb_handlers_setendsubmsg(h, f, textprinter_endsubmsg, &attr);
         break;
@@ -12485,9 +8680,9 @@
 
 /* Public API *****************************************************************/
 
-upb_textprinter *upb_textprinter_create(upb_env *env, const upb_handlers *h,
-                                        upb_bytessink *output) {
-  upb_textprinter *p = upb_env_malloc(env, sizeof(upb_textprinter));
+upb_textprinter *upb_textprinter_create(upb_arena *arena, const upb_handlers *h,
+                                        upb_bytessink output) {
+  upb_textprinter *p = upb_arena_malloc(arena, sizeof(upb_textprinter));
   if (!p) return NULL;
 
   p->output_ = output;
@@ -12497,12 +8692,11 @@
   return p;
 }
 
-const upb_handlers *upb_textprinter_newhandlers(const upb_msgdef *m,
-                                                const void *owner) {
-  return upb_handlers_newfrozen(m, owner, &onmreg, NULL);
+upb_handlercache *upb_textprinter_newcache() {
+  return upb_handlercache_new(&onmreg, NULL);
 }
 
-upb_sink *upb_textprinter_input(upb_textprinter *p) { return &p->input_; }
+upb_sink upb_textprinter_input(upb_textprinter *p) { return p->input_; }
 
 void upb_textprinter_setsingleline(upb_textprinter *p, bool single_line) {
   p->single_line_ = single_line;
@@ -12603,6 +8797,10 @@
 ** - handling of keys/escape-sequences/etc that span input buffers.
 */
 
+/* Need to define _XOPEN_SOURCE before any include to make strptime work. */
+#define _XOPEN_SOURCE 700
+
+#include <ctype.h>
 #include <errno.h>
 #include <float.h>
 #include <math.h>
@@ -12610,6 +8808,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+
 #include <time.h>
 
 
@@ -12638,7 +8837,6 @@
 static bool does_string_wrapper_start(upb_json_parser *p);
 static bool does_string_wrapper_end(upb_json_parser *p);
 
-static bool is_fieldmask_object(upb_json_parser *p);
 static bool does_fieldmask_start(upb_json_parser *p);
 static bool does_fieldmask_end(upb_json_parser *p);
 static void start_fieldmask_object(upb_json_parser *p);
@@ -12735,14 +8933,13 @@
 
 typedef struct {
   /* For encoding Any value field in binary format. */
-  const upb_handlers *encoder_handlers;
-  upb_pb_encoder *encoder;
+  upb_handlercache *encoder_handlercache;
   upb_stringsink stringsink;
 
   /* For decoding Any value field in json format. */
-  upb_json_parsermethod *parser_method;
-  upb_json_parser* parser;
+  upb_json_codecache *parser_codecache;
   upb_sink sink;
+  upb_json_parser *parser;
 
   /* Mark the range of uninterpreted values in json input before type url. */
   const char *before_type_url_start;
@@ -12761,7 +8958,7 @@
   const upb_fielddef *f;
 
   /* The table mapping json name to fielddef for this message. */
-  upb_strtable *name_table;
+  const upb_strtable *name_table;
 
   /* We are in a repeated-field context, ready to emit mapentries as
    * submessages. This flag alters the start-of-object (open-brace) behavior to
@@ -12794,7 +8991,7 @@
 } upb_jsonparser_frame;
 
 struct upb_json_parser {
-  upb_env *env;
+  upb_arena *arena;
   const upb_json_parsermethod *method;
   upb_bytessink input_;
 
@@ -12803,7 +9000,7 @@
   upb_jsonparser_frame *top;
   upb_jsonparser_frame *limit;
 
-  upb_status status;
+  upb_status *status;
 
   /* Ragel's internal parsing stack for the parsing state machine. */
   int current_state;
@@ -12840,64 +9037,68 @@
   struct tm tm;
 };
 
-struct upb_json_parsermethod {
-  upb_refcounted base;
+struct upb_json_codecache {
+  upb_arena *arena;
+  upb_inttable methods;   /* upb_msgdef* -> upb_json_parsermethod* */
+};
 
+struct upb_json_parsermethod {
+  const upb_json_codecache *cache;
   upb_byteshandler input_handler_;
 
-  /* Mainly for the purposes of refcounting, so all the fielddefs we point
-   * to stay alive. */
-  const upb_msgdef *msg;
-
-  /* Keys are upb_msgdef*, values are upb_strtable (json_name -> fielddef) */
-  upb_inttable name_tables;
+  /* Maps json_name -> fielddef */
+  upb_strtable name_table;
 };
 
 #define PARSER_CHECK_RETURN(x) if (!(x)) return false
 
-static void json_parser_any_frame_reset(upb_jsonparser_any_frame *frame) {
-  frame->encoder_handlers = NULL;
-  frame->encoder = NULL;
-  frame->parser_method = NULL;
+static upb_jsonparser_any_frame *json_parser_any_frame_new(
+    upb_json_parser *p) {
+  upb_jsonparser_any_frame *frame;
+
+  frame = upb_arena_malloc(p->arena, sizeof(upb_jsonparser_any_frame));
+
+  frame->encoder_handlercache = upb_pb_encoder_newcache();
+  frame->parser_codecache = upb_json_codecache_new();
   frame->parser = NULL;
   frame->before_type_url_start = NULL;
   frame->before_type_url_end = NULL;
   frame->after_type_url_start = NULL;
+
+  upb_stringsink_init(&frame->stringsink);
+
+  return frame;
 }
 
 static void json_parser_any_frame_set_payload_type(
     upb_json_parser *p,
     upb_jsonparser_any_frame *frame,
     const upb_msgdef *payload_type) {
+  const upb_handlers *h;
+  const upb_json_parsermethod *parser_method;
+  upb_pb_encoder *encoder;
+
   /* Initialize encoder. */
-  frame->encoder_handlers =
-      upb_pb_encoder_newhandlers(payload_type, &frame->encoder_handlers);
-  upb_stringsink_init(&frame->stringsink);
-  frame->encoder =
-      upb_pb_encoder_create(
-          p->env, frame->encoder_handlers,
-          &frame->stringsink.sink);
+  h = upb_handlercache_get(frame->encoder_handlercache, payload_type);
+  encoder = upb_pb_encoder_create(p->arena, h, frame->stringsink.sink);
 
   /* Initialize parser. */
-  frame->parser_method =
-      upb_json_parsermethod_new(payload_type, &frame->parser_method);
-  upb_sink_reset(&frame->sink, frame->encoder_handlers, frame->encoder);
+  parser_method = upb_json_codecache_get(frame->parser_codecache, payload_type);
+  upb_sink_reset(&frame->sink, h, encoder);
   frame->parser =
-      upb_json_parser_create(p->env, frame->parser_method, p->symtab,
-                             &frame->sink, p->ignore_json_unknown);
+      upb_json_parser_create(p->arena, parser_method, p->symtab, frame->sink,
+                             p->status, p->ignore_json_unknown);
 }
 
 static void json_parser_any_frame_free(upb_jsonparser_any_frame *frame) {
-  upb_handlers_unref(frame->encoder_handlers,
-                     &frame->encoder_handlers);
-  upb_json_parsermethod_unref(frame->parser_method,
-                              &frame->parser_method);
+  upb_handlercache_free(frame->encoder_handlercache);
+  upb_json_codecache_free(frame->parser_codecache);
   upb_stringsink_uninit(&frame->stringsink);
 }
 
 static bool json_parser_any_frame_has_type_url(
   upb_jsonparser_any_frame *frame) {
-  return frame->encoder != NULL;
+  return frame->parser != NULL;
 }
 
 static bool json_parser_any_frame_has_value_before_type_url(
@@ -12919,7 +9120,7 @@
 static void json_parser_any_frame_set_before_type_url_end(
     upb_jsonparser_any_frame *frame,
     const char *ptr) {
-  if (frame->encoder == NULL) {
+  if (frame->parser == NULL) {
     frame->before_type_url_end = ptr;
   }
 }
@@ -12951,8 +9152,7 @@
 
 static bool check_stack(upb_json_parser *p) {
   if ((p->top + 1) == p->limit) {
-    upb_status_seterrmsg(&p->status, "Nesting too deep");
-    upb_env_reporterror(p->env, &p->status);
+    upb_status_seterrmsg(p->status, "Nesting too deep");
     return false;
   }
 
@@ -12961,9 +9161,15 @@
 
 static void set_name_table(upb_json_parser *p, upb_jsonparser_frame *frame) {
   upb_value v;
-  bool ok = upb_inttable_lookupptr(&p->method->name_tables, frame->m, &v);
+  const upb_json_codecache *cache = p->method->cache;
+  bool ok;
+  const upb_json_parsermethod *method;
+
+  ok = upb_inttable_lookupptr(&cache->methods, frame->m, &v);
   UPB_ASSERT(ok);
-  frame->name_table = upb_value_getptr(v);
+  method = upb_value_getconstptr(v);
+
+  frame->name_table = &method->name_table;
 }
 
 /* There are GCC/Clang built-ins for overflow checking which we could start
@@ -13041,10 +9247,9 @@
     char output[3];
 
     if (limit - ptr < 4) {
-      upb_status_seterrf(&p->status,
+      upb_status_seterrf(p->status,
                          "Base64 input for bytes field not a multiple of 4: %s",
                          upb_fielddef_name(p->top->f));
-      upb_env_reporterror(p->env, &p->status);
       return false;
     }
 
@@ -13061,17 +9266,16 @@
     output[0] = val >> 16;
     output[1] = (val >> 8) & 0xff;
     output[2] = val & 0xff;
-    upb_sink_putstring(&p->top->sink, sel, output, 3, NULL);
+    upb_sink_putstring(p->top->sink, sel, output, 3, NULL);
   }
   return true;
 
 otherchar:
   if (nonbase64(ptr[0]) || nonbase64(ptr[1]) || nonbase64(ptr[2]) ||
       nonbase64(ptr[3]) ) {
-    upb_status_seterrf(&p->status,
+    upb_status_seterrf(p->status,
                        "Non-base64 characters in bytes field: %s",
                        upb_fielddef_name(p->top->f));
-    upb_env_reporterror(p->env, &p->status);
     return false;
   } if (ptr[2] == '=') {
     uint32_t val;
@@ -13087,7 +9291,7 @@
 
     UPB_ASSERT(!(val & 0x80000000));
     output = val >> 16;
-    upb_sink_putstring(&p->top->sink, sel, &output, 1, NULL);
+    upb_sink_putstring(p->top->sink, sel, &output, 1, NULL);
     return true;
   } else {
     uint32_t val;
@@ -13104,16 +9308,15 @@
 
     output[0] = val >> 16;
     output[1] = (val >> 8) & 0xff;
-    upb_sink_putstring(&p->top->sink, sel, output, 2, NULL);
+    upb_sink_putstring(p->top->sink, sel, output, 2, NULL);
     return true;
   }
 
 badpadding:
-  upb_status_seterrf(&p->status,
+  upb_status_seterrf(p->status,
                      "Incorrect base64 padding for field: %s (%.*s)",
                      upb_fielddef_name(p->top->f),
                      4, ptr);
-  upb_env_reporterror(p->env, &p->status);
   return false;
 }
 
@@ -13157,10 +9360,9 @@
     new_size = saturating_multiply(new_size, 2);
   }
 
-  mem = upb_env_realloc(p->env, p->accumulate_buf, old_size, new_size);
+  mem = upb_arena_realloc(p->arena, p->accumulate_buf, old_size, new_size);
   if (!mem) {
-    upb_status_seterrmsg(&p->status, "Out of memory allocating buffer.");
-    upb_env_reporterror(p->env, &p->status);
+    upb_status_seterrmsg(p->status, "Out of memory allocating buffer.");
     return false;
   }
 
@@ -13183,8 +9385,7 @@
   }
 
   if (!checked_add(p->accumulated_len, len, &need)) {
-    upb_status_seterrmsg(&p->status, "Integer overflow.");
-    upb_env_reporterror(p->env, &p->status);
+    upb_status_seterrmsg(p->status, "Integer overflow.");
     return false;
   }
 
@@ -13262,8 +9463,7 @@
   switch (p->multipart_state) {
     case MULTIPART_INACTIVE:
       upb_status_seterrmsg(
-          &p->status, "Internal error: unexpected state MULTIPART_INACTIVE");
-      upb_env_reporterror(p->env, &p->status);
+          p->status, "Internal error: unexpected state MULTIPART_INACTIVE");
       return false;
 
     case MULTIPART_ACCUMULATE:
@@ -13274,7 +9474,7 @@
 
     case MULTIPART_PUSHEAGERLY: {
       const upb_bufhandle *handle = can_alias ? p->handle : NULL;
-      upb_sink_putstring(&p->top->sink, p->string_selector, buf, len, handle);
+      upb_sink_putstring(p->top->sink, p->string_selector, buf, len, handle);
       break;
     }
   }
@@ -13322,7 +9522,7 @@
   if (multipart_text(p, p->capture, *ptr - p->capture, false)) {
     /* We use this as a signal that we were in the middle of capturing, and
      * that capturing should resume at the beginning of the next buffer.
-     *
+     * 
      * We can't use *ptr here, because we have no guarantee that this pointer
      * will be valid when we resume (if the underlying memory is freed, then
      * using the pointer at all, even to compare to NULL, is likely undefined
@@ -13520,7 +9720,7 @@
       } else if (val > INT32_MAX || val < INT32_MIN) {
         return false;
       } else {
-        upb_sink_putint32(&p->top->sink, parser_getsel(p), val);
+        upb_sink_putint32(p->top->sink, parser_getsel(p), val);
         return true;
       }
     }
@@ -13531,7 +9731,7 @@
       } else if (val > UINT32_MAX || errno == ERANGE) {
         return false;
       } else {
-        upb_sink_putuint32(&p->top->sink, parser_getsel(p), val);
+        upb_sink_putuint32(p->top->sink, parser_getsel(p), val);
         return true;
       }
     }
@@ -13542,7 +9742,7 @@
       if (errno == ERANGE || end != bufend) {
         break;
       } else {
-        upb_sink_putint64(&p->top->sink, parser_getsel(p), val);
+        upb_sink_putint64(p->top->sink, parser_getsel(p), val);
         return true;
       }
     }
@@ -13553,7 +9753,7 @@
       } else if (errno == ERANGE) {
         return false;
       } else {
-        upb_sink_putuint64(&p->top->sink, parser_getsel(p), val);
+        upb_sink_putuint64(p->top->sink, parser_getsel(p), val);
         return true;
       }
     }
@@ -13584,7 +9784,7 @@
       if (modf(val, &dummy) != 0 || val > max || val < min) {             \
         return false;                                                     \
       } else {                                                            \
-        upb_sink_put ## smalltype(&p->top->sink, parser_getsel(p),        \
+        upb_sink_put ## smalltype(p->top->sink, parser_getsel(p),        \
                                   (ctype)val);                            \
         return true;                                                      \
       }                                                                   \
@@ -13598,13 +9798,13 @@
 #undef CASE
 
     case UPB_TYPE_DOUBLE:
-      upb_sink_putdouble(&p->top->sink, parser_getsel(p), val);
+      upb_sink_putdouble(p->top->sink, parser_getsel(p), val);
       return true;
     case UPB_TYPE_FLOAT:
       if ((val > FLT_MAX || val < -FLT_MAX) && val != inf && val != -inf) {
         return false;
       } else {
-        upb_sink_putfloat(&p->top->sink, parser_getsel(p), val);
+        upb_sink_putfloat(p->top->sink, parser_getsel(p), val);
         return true;
       }
     default:
@@ -13628,8 +9828,7 @@
     multipart_end(p);
     return true;
   } else {
-    upb_status_seterrf(&p->status, "error parsing number: %s", buf);
-    upb_env_reporterror(p->env, &p->status);
+    upb_status_seterrf(p->status, "error parsing number: %s", buf);
     multipart_end(p);
     return false;
   }
@@ -13643,14 +9842,13 @@
   }
 
   if (upb_fielddef_type(p->top->f) != UPB_TYPE_BOOL) {
-    upb_status_seterrf(&p->status,
+    upb_status_seterrf(p->status,
                        "Boolean value specified for non-bool field: %s",
                        upb_fielddef_name(p->top->f));
-    upb_env_reporterror(p->env, &p->status);
     return false;
   }
 
-  ok = upb_sink_putbool(&p->top->sink, parser_getsel(p), val);
+  ok = upb_sink_putbool(p->top->sink, parser_getsel(p), val);
   UPB_ASSERT(ok);
 
   return true;
@@ -13799,7 +9997,7 @@
      * handler frames, and string events occur in a sub-frame. */
     inner = p->top + 1;
     sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSTR);
-    upb_sink_startstr(&p->top->sink, sel, 0, &inner->sink);
+    upb_sink_startstr(p->top->sink, sel, 0, &inner->sink);
     inner->m = p->top->m;
     inner->f = p->top->f;
     inner->name_table = NULL;
@@ -13830,10 +10028,9 @@
     multipart_startaccum(p);
     return true;
   } else {
-    upb_status_seterrf(&p->status,
+    upb_status_seterrf(p->status,
                        "String specified for bool or submessage field: %s",
                        upb_fielddef_name(p->top->f));
-    upb_env_reporterror(p->env, &p->status);
     return false;
   }
 }
@@ -13849,11 +10046,11 @@
   inner = p->top + 1;
 
   sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSTR);
-  upb_sink_startstr(&p->top->sink, sel, 0, &inner->sink);
+  upb_sink_startstr(p->top->sink, sel, 0, &inner->sink);
   sel = getsel_for_handlertype(p, UPB_HANDLER_STRING);
-  upb_sink_putstring(&inner->sink, sel, buf, len, NULL);
+  upb_sink_putstring(inner->sink, sel, buf, len, NULL);
   sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSTR);
-  upb_sink_endstr(&inner->sink, sel);
+  upb_sink_endstr(inner->sink, sel);
 
   multipart_end(p);
 
@@ -13866,8 +10063,7 @@
     payload_type = upb_symtab_lookupmsg2(p->symtab, buf, len);
     if (payload_type == NULL) {
       upb_status_seterrf(
-          &p->status, "Cannot find packed type: %.*s\n", (int)len, buf);
-      upb_env_reporterror(p->env, &p->status);
+          p->status, "Cannot find packed type: %.*s\n", (int)len, buf);
       return false;
     }
 
@@ -13876,8 +10072,7 @@
     return true;
   } else {
     upb_status_seterrf(
-        &p->status, "Invalid type url: %.*s\n", (int)len, buf);
-    upb_env_reporterror(p->env, &p->status);
+        p->status, "Invalid type url: %.*s\n", (int)len, buf);
     return false;
   }
 }
@@ -13910,15 +10105,14 @@
 
     case UPB_TYPE_STRING: {
       upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSTR);
-      upb_sink_endstr(&p->top->sink, sel);
+      upb_sink_endstr(p->top->sink, sel);
       p->top--;
       break;
     }
 
     case UPB_TYPE_ENUM: {
       /* Resolve enum symbolic name to integer value. */
-      const upb_enumdef *enumdef =
-          (const upb_enumdef*)upb_fielddef_subdef(p->top->f);
+      const upb_enumdef *enumdef = upb_fielddef_enumsubdef(p->top->f);
 
       size_t len;
       const char *buf = accumulate_getptr(p, &len);
@@ -13928,10 +10122,9 @@
 
       if (ok) {
         upb_selector_t sel = parser_getsel(p);
-        upb_sink_putint32(&p->top->sink, sel, int_val);
+        upb_sink_putint32(p->top->sink, sel, int_val);
       } else {
-        upb_status_seterrf(&p->status, "Enum value unknown: '%.*s'", len, buf);
-        upb_env_reporterror(p->env, &p->status);
+        upb_status_seterrf(p->status, "Enum value unknown: '%.*s'", len, buf);
       }
 
       break;
@@ -13948,8 +10141,7 @@
 
     default:
       UPB_ASSERT(false);
-      upb_status_seterrmsg(&p->status, "Internal error in JSON decoder");
-      upb_env_reporterror(p->env, &p->status);
+      upb_status_seterrmsg(p->status, "Internal error in JSON decoder");
       ok = false;
       break;
   }
@@ -14039,25 +10231,22 @@
   memcpy(seconds_buf, buf, fraction_start);
   seconds = strtol(seconds_buf, &end, 10);
   if (errno == ERANGE || end != seconds_buf + fraction_start) {
-    upb_status_seterrf(&p->status, "error parsing duration: %s",
+    upb_status_seterrf(p->status, "error parsing duration: %s",
                        seconds_buf);
-    upb_env_reporterror(p->env, &p->status);
     return false;
   }
 
   if (seconds > 315576000000) {
-    upb_status_seterrf(&p->status, "error parsing duration: "
+    upb_status_seterrf(p->status, "error parsing duration: "
                                    "maximum acceptable value is "
                                    "315576000000");
-    upb_env_reporterror(p->env, &p->status);
     return false;
   }
 
   if (seconds < -315576000000) {
-    upb_status_seterrf(&p->status, "error parsing duration: "
+    upb_status_seterrf(p->status, "error parsing duration: "
                                    "minimum acceptable value is "
                                    "-315576000000");
-    upb_env_reporterror(p->env, &p->status);
     return false;
   }
 
@@ -14066,9 +10255,8 @@
   memcpy(nanos_buf + 1, buf + fraction_start, len - fraction_start);
   val = strtod(nanos_buf, &end);
   if (errno == ERANGE || end != nanos_buf + len - fraction_start + 1) {
-    upb_status_seterrf(&p->status, "error parsing duration: %s",
+    upb_status_seterrf(p->status, "error parsing duration: %s",
                        nanos_buf);
-    upb_env_reporterror(p->env, &p->status);
     return false;
   }
 
@@ -14083,7 +10271,7 @@
   capture_begin(p, seconds_membername);
   capture_end(p, seconds_membername + 7);
   end_membername(p);
-  upb_sink_putint64(&p->top->sink, parser_getsel(p), seconds);
+  upb_sink_putint64(p->top->sink, parser_getsel(p), seconds);
   end_member(p);
 
   /* Set nanos */
@@ -14091,10 +10279,10 @@
   capture_begin(p, nanos_membername);
   capture_end(p, nanos_membername + 5);
   end_membername(p);
-  upb_sink_putint32(&p->top->sink, parser_getsel(p), nanos);
+  upb_sink_putint32(p->top->sink, parser_getsel(p), nanos);
   end_member(p);
 
-  /* Continue previous environment */
+  /* Continue previous arena */
   multipart_startaccum(p);
 
   return true;
@@ -14123,15 +10311,13 @@
   timestamp_buf[UPB_TIMESTAMP_BASE_SIZE + 3] = 0;
 
 #if defined __MINGW32__ || defined __MINGW64__
-  upb_status_seterrf(
-      &p->status, "error parsing timestamp: mingw doesn't support strptime");
-  upb_env_reporterror(p->env, &p->status);
+  upb_status_seterrf(p->status,
+                     "error parsing timestamp: mingw doesn't support strptime");
   return false;
 #else
   /* Parse seconds */
   if (strptime(timestamp_buf, "%FT%H:%M:%S%Z", &p->tm) == NULL) {
-    upb_status_seterrf(&p->status, "error parsing timestamp: %s", buf);
-    upb_env_reporterror(p->env, &p->status);
+    upb_status_seterrf(p->status, "error parsing timestamp: %s", buf);
     return false;
   }
 #endif
@@ -14165,9 +10351,8 @@
   buf = accumulate_getptr(p, &len);
 
   if (len > 10) {
-    upb_status_seterrf(&p->status,
+    upb_status_seterrf(p->status,
         "error parsing timestamp: at most 9-digit fraction.");
-    upb_env_reporterror(p->env, &p->status);
     return false;
   }
 
@@ -14177,9 +10362,8 @@
   val = strtod(nanos_buf, &end);
 
   if (errno == ERANGE || end != nanos_buf + len + 1) {
-    upb_status_seterrf(&p->status, "error parsing timestamp nanos: %s",
+    upb_status_seterrf(p->status, "error parsing timestamp nanos: %s",
                        nanos_buf);
-    upb_env_reporterror(p->env, &p->status);
     return false;
   }
 
@@ -14193,7 +10377,7 @@
   capture_begin(p, nanos_membername);
   capture_end(p, nanos_membername + 5);
   end_membername(p);
-  upb_sink_putint32(&p->top->sink, parser_getsel(p), nanos);
+  upb_sink_putint32(p->top->sink, parser_getsel(p), nanos);
   end_member(p);
 
   /* Continue previous environment */
@@ -14221,8 +10405,7 @@
 
   if (buf[0] != 'Z') {
     if (sscanf(buf + 1, "%2d:00", &hours) != 1) {
-      upb_status_seterrf(&p->status, "error parsing timestamp offset");
-      upb_env_reporterror(p->env, &p->status);
+      upb_status_seterrf(p->status, "error parsing timestamp offset");
       return false;
     }
 
@@ -14238,10 +10421,9 @@
 
   /* Check timestamp boundary */
   if (seconds < -62135596800) {
-    upb_status_seterrf(&p->status, "error parsing timestamp: "
+    upb_status_seterrf(p->status, "error parsing timestamp: "
                                    "minimum acceptable value is "
                                    "0001-01-01T00:00:00Z");
-    upb_env_reporterror(p->env, &p->status);
     return false;
   }
 
@@ -14253,7 +10435,7 @@
   capture_begin(p, seconds_membername);
   capture_end(p, seconds_membername + 7);
   end_membername(p);
-  upb_sink_putint64(&p->top->sink, parser_getsel(p), seconds);
+  upb_sink_putint64(p->top->sink, parser_getsel(p), seconds);
   end_member(p);
 
   /* Continue previous environment */
@@ -14267,9 +10449,7 @@
 }
 
 static bool end_fieldmask_path_text(upb_json_parser *p, const char *ptr) {
-  if (!capture_end(p, ptr)) {
-    return false;
-  }
+  return capture_end(p, ptr);
 }
 
 static bool start_fieldmask_path(upb_json_parser *p) {
@@ -14282,7 +10462,7 @@
    * handler frames, and string events occur in a sub-frame. */
   inner = p->top + 1;
   sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSTR);
-  upb_sink_startstr(&p->top->sink, sel, 0, &inner->sink);
+  upb_sink_startstr(p->top->sink, sel, 0, &inner->sink);
   inner->m = p->top->m;
   inner->f = p->top->f;
   inner->name_table = NULL;
@@ -14304,10 +10484,10 @@
   for (;ptr < limit; ptr++) {
     if (*ptr >= 'A' && *ptr <= 'Z' && !first) {
       char lower = tolower(*ptr);
-      upb_sink_putstring(&p->top->sink, sel, "_", 1, NULL);
-      upb_sink_putstring(&p->top->sink, sel, &lower, 1, NULL);
+      upb_sink_putstring(p->top->sink, sel, "_", 1, NULL);
+      upb_sink_putstring(p->top->sink, sel, &lower, 1, NULL);
     } else {
-      upb_sink_putstring(&p->top->sink, sel, ptr, 1, NULL);
+      upb_sink_putstring(p->top->sink, sel, ptr, 1, NULL);
     }
     first = false;
   }
@@ -14324,7 +10504,7 @@
   }
 
   sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSTR);
-  upb_sink_endstr(&p->top->sink, sel);
+  upb_sink_endstr(p->top->sink, sel);
   p->top--;
 
   multipart_end(p);
@@ -14351,8 +10531,7 @@
 
   p->top->f = upb_msgdef_itof(p->top->m, UPB_MAPENTRY_KEY);
   if (p->top->f == NULL) {
-    upb_status_seterrmsg(&p->status, "mapentry message has no key");
-    upb_env_reporterror(p->env, &p->status);
+    upb_status_seterrmsg(p->status, "mapentry message has no key");
     return false;
   }
   switch (upb_fielddef_type(p->top->f)) {
@@ -14375,9 +10554,8 @@
           return false;
         }
       } else {
-        upb_status_seterrmsg(&p->status,
+        upb_status_seterrmsg(p->status,
                              "Map bool key not 'true' or 'false'");
-        upb_env_reporterror(p->env, &p->status);
         return false;
       }
       multipart_end(p);
@@ -14386,17 +10564,16 @@
     case UPB_TYPE_BYTES: {
       upb_sink subsink;
       upb_selector_t sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSTR);
-      upb_sink_startstr(&p->top->sink, sel, len, &subsink);
+      upb_sink_startstr(p->top->sink, sel, len, &subsink);
       sel = getsel_for_handlertype(p, UPB_HANDLER_STRING);
-      upb_sink_putstring(&subsink, sel, buf, len, NULL);
+      upb_sink_putstring(subsink, sel, buf, len, NULL);
       sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSTR);
-      upb_sink_endstr(&subsink, sel);
+      upb_sink_endstr(subsink, sel);
       multipart_end(p);
       break;
     }
     default:
-      upb_status_seterrmsg(&p->status, "Invalid field type for map key");
-      upb_env_reporterror(p->env, &p->status);
+      upb_status_seterrmsg(p->status, "Invalid field type for map key");
       return false;
   }
 
@@ -14429,7 +10606,7 @@
   inner = p->top + 1;
   p->top->f = mapfield;
   sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSUBMSG);
-  upb_sink_startsubmsg(&p->top->sink, sel, &inner->sink);
+  upb_sink_startsubmsg(p->top->sink, sel, &inner->sink);
   inner->m = mapentrymsg;
   inner->name_table = NULL;
   inner->mapfield = mapfield;
@@ -14446,7 +10623,7 @@
   p->top = inner;
 
   /* send STARTMSG in submsg frame. */
-  upb_sink_startmsg(&p->top->sink);
+  upb_sink_startmsg(p->top->sink);
 
   parse_mapentry_key(p);
 
@@ -14455,8 +10632,7 @@
   p->top->is_mapentry = true;  /* set up to pop frame after value is parsed. */
   p->top->mapfield = mapfield;
   if (p->top->f == NULL) {
-    upb_status_seterrmsg(&p->status, "mapentry message has no value");
-    upb_env_reporterror(p->env, &p->status);
+    upb_status_seterrmsg(p->status, "mapentry message has no value");
     return false;
   }
 
@@ -14491,8 +10667,7 @@
       multipart_end(p);
       return true;
     } else {
-      upb_status_seterrf(&p->status, "No such field: %.*s\n", (int)len, buf);
-      upb_env_reporterror(p->env, &p->status);
+      upb_status_seterrf(p->status, "No such field: %.*s\n", (int)len, buf);
       return false;
     }
   }
@@ -14518,21 +10693,20 @@
 static void end_member(upb_json_parser *p) {
   /* If we just parsed a map-entry value, end that frame too. */
   if (p->top->is_mapentry) {
-    upb_status s = UPB_STATUS_INIT;
     upb_selector_t sel;
     bool ok;
     const upb_fielddef *mapfield;
 
     UPB_ASSERT(p->top > p->stack);
     /* send ENDMSG on submsg. */
-    upb_sink_endmsg(&p->top->sink, &s);
+    upb_sink_endmsg(p->top->sink, p->status);
     mapfield = p->top->mapfield;
 
     /* send ENDSUBMSG in repeated-field-of-mapentries frame. */
     p->top--;
     ok = upb_handlers_getselector(mapfield, UPB_HANDLER_ENDSUBMSG, &sel);
     UPB_ASSERT(ok);
-    upb_sink_endsubmsg(&p->top->sink, sel);
+    upb_sink_endsubmsg(p->top->sink, sel);
   }
 
   p->top->f = NULL;
@@ -14576,7 +10750,7 @@
 
     inner = p->top + 1;
     sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSEQ);
-    upb_sink_startseq(&p->top->sink, sel, &inner->sink);
+    upb_sink_startseq(p->top->sink, sel, &inner->sink);
     inner->m = upb_fielddef_msgsubdef(p->top->f);
     inner->name_table = NULL;
     inner->mapfield = p->top->f;
@@ -14600,7 +10774,7 @@
     inner = p->top + 1;
 
     sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSUBMSG);
-    upb_sink_startsubmsg(&p->top->sink, sel, &inner->sink);
+    upb_sink_startsubmsg(p->top->sink, sel, &inner->sink);
     inner->m = upb_fielddef_msgsubdef(p->top->f);
     set_name_table(p, inner);
     inner->f = NULL;
@@ -14611,9 +10785,7 @@
 
     if (is_wellknown_msg(p, UPB_WELLKNOWN_ANY)) {
       p->top->is_any = true;
-      p->top->any_frame =
-          upb_env_malloc(p->env, sizeof(upb_jsonparser_any_frame));
-      json_parser_any_frame_reset(p->top->any_frame);
+      p->top->any_frame = json_parser_any_frame_new(p);
     } else {
       p->top->is_any = false;
       p->top->any_frame = NULL;
@@ -14621,10 +10793,9 @@
 
     return true;
   } else {
-    upb_status_seterrf(&p->status,
+    upb_status_seterrf(p->status,
                        "Object specified for non-message/group field: %s",
                        upb_fielddef_name(p->top->f));
-    upb_env_reporterror(p->env, &p->status);
     return false;
   }
 }
@@ -14662,14 +10833,14 @@
     upb_selector_t sel;
     p->top--;
     sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSEQ);
-    upb_sink_endseq(&p->top->sink, sel);
+    upb_sink_endseq(p->top->sink, sel);
   } else {
     upb_selector_t sel;
     bool is_unknown = p->top->m == NULL;
     p->top--;
     if (!is_unknown) {
       sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSUBMSG);
-      upb_sink_endsubmsg(&p->top->sink, sel);
+      upb_sink_endsubmsg(p->top->sink, sel);
     }
   }
 }
@@ -14732,10 +10903,9 @@
   }
 
   if (!upb_fielddef_isseq(p->top->f)) {
-    upb_status_seterrf(&p->status,
+    upb_status_seterrf(p->status,
                        "Array specified for non-repeated field: %s",
                        upb_fielddef_name(p->top->f));
-    upb_env_reporterror(p->env, &p->status);
     return false;
   }
 
@@ -14743,7 +10913,7 @@
 
   inner = p->top + 1;
   sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSEQ);
-  upb_sink_startseq(&p->top->sink, sel, &inner->sink);
+  upb_sink_startseq(p->top->sink, sel, &inner->sink);
   inner->m = p->top->m;
   inner->name_table = NULL;
   inner->f = p->top->f;
@@ -14769,7 +10939,7 @@
   }
 
   sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSEQ);
-  upb_sink_endseq(&p->top->sink, sel);
+  upb_sink_endseq(p->top->sink, sel);
 
   if (is_wellknown_msg(p, UPB_WELLKNOWN_LISTVALUE)) {
     end_listvalue_object(p);
@@ -14788,18 +10958,13 @@
 
 static void start_object(upb_json_parser *p) {
   if (!p->top->is_map && p->top->m != NULL) {
-    upb_sink_startmsg(&p->top->sink);
+    upb_sink_startmsg(p->top->sink);
   }
 }
 
 static void end_object(upb_json_parser *p) {
   if (!p->top->is_map && p->top->m != NULL) {
-    upb_status status;
-    upb_status_clear(&status);
-    upb_sink_endmsg(&p->top->sink, &status);
-    if (!upb_ok(&status)) {
-      upb_env_reporterror(p->env, &status);
-    }
+    upb_sink_endmsg(p->top->sink, p->status);
   }
 }
 
@@ -14818,8 +10983,7 @@
 
   if (json_parser_any_frame_has_value(p->top->any_frame) &&
       !json_parser_any_frame_has_type_url(p->top->any_frame)) {
-    upb_status_seterrmsg(&p->status, "No valid type url");
-    upb_env_reporterror(p->env, &p->status);
+    upb_status_seterrmsg(p->status, "No valid type url");
     return false;
   }
 
@@ -14834,8 +10998,7 @@
                  p->top->any_frame->before_type_url_end -
                  p->top->any_frame->before_type_url_start);
       if (p->top->any_frame->before_type_url_start == NULL) {
-        upb_status_seterrmsg(&p->status, "invalid data for well known type.");
-        upb_env_reporterror(p->env, &p->status);
+        upb_status_seterrmsg(p->status, "invalid data for well known type.");
         return false;
       }
       p->top->any_frame->before_type_url_start++;
@@ -14847,8 +11010,7 @@
                  (ptr + 1) -
                  p->top->any_frame->after_type_url_start);
       if (p->top->any_frame->after_type_url_start == NULL) {
-        upb_status_seterrmsg(&p->status, "Invalid data for well known type.");
-        upb_env_reporterror(p->env, &p->status);
+        upb_status_seterrmsg(p->status, "Invalid data for well known type.");
         return false;
       }
       p->top->any_frame->after_type_url_start++;
@@ -14908,12 +11070,12 @@
   inner = p->top + 1;
 
   sel = getsel_for_handlertype(p, UPB_HANDLER_STARTSTR);
-  upb_sink_startstr(&p->top->sink, sel, 0, &inner->sink);
+  upb_sink_startstr(p->top->sink, sel, 0, &inner->sink);
   sel = getsel_for_handlertype(p, UPB_HANDLER_STRING);
-  upb_sink_putstring(&inner->sink, sel, p->top->any_frame->stringsink.ptr,
+  upb_sink_putstring(inner->sink, sel, p->top->any_frame->stringsink.ptr,
                      p->top->any_frame->stringsink.len, NULL);
   sel = getsel_for_handlertype(p, UPB_HANDLER_ENDSTR);
-  upb_sink_endstr(&inner->sink, sel);
+  upb_sink_endstr(inner->sink, sel);
 
   end_member(p);
 
@@ -14921,7 +11083,6 @@
 
   /* Deallocate any parse frame. */
   json_parser_any_frame_free(p->top->any_frame);
-  upb_env_free(p->env, p->top->any_frame);
 
   return true;
 }
@@ -15105,10 +11266,6 @@
   return p->top->m != NULL && is_fieldmask(p->top->m);
 }
 
-static bool is_fieldmask_object(upb_json_parser *p) {
-  return p->top->m != NULL && is_fieldmask(p->top->m);
-}
-
 #define CHECK_RETURN_TOP(x) if (!(x)) goto error
 
 
@@ -15130,248 +11287,248 @@
  * final state once, when the closing '"' is seen. */
 
 
-#line 2730 "upb/json/parser.rl"
+#line 2695 "upb/json/parser.rl"
 
 
 
-#line 2556 "upb/json/parser.c"
+#line 2521 "upb/json/parser.c"
 static const char _json_actions[] = {
-	0, 1, 0, 1, 1, 1, 3, 1,
-	4, 1, 6, 1, 7, 1, 8, 1,
-	9, 1, 10, 1, 11, 1, 12, 1,
-	13, 1, 24, 1, 26, 1, 28, 1,
-	29, 1, 31, 1, 32, 1, 33, 1,
-	35, 1, 37, 1, 38, 1, 39, 1,
-	40, 1, 42, 1, 43, 2, 4, 9,
-	2, 5, 6, 2, 7, 3, 2, 7,
-	9, 2, 14, 15, 2, 16, 17, 2,
-	18, 19, 2, 21, 23, 2, 22, 20,
-	2, 27, 25, 2, 29, 31, 2, 34,
-	2, 2, 35, 43, 2, 36, 25, 2,
-	38, 43, 2, 39, 43, 2, 40, 43,
-	2, 41, 30, 2, 42, 43, 3, 21,
+	0, 1, 0, 1, 1, 1, 3, 1, 
+	4, 1, 6, 1, 7, 1, 8, 1, 
+	9, 1, 10, 1, 11, 1, 12, 1, 
+	13, 1, 24, 1, 26, 1, 28, 1, 
+	29, 1, 31, 1, 32, 1, 33, 1, 
+	35, 1, 37, 1, 38, 1, 39, 1, 
+	40, 1, 42, 1, 43, 2, 4, 9, 
+	2, 5, 6, 2, 7, 3, 2, 7, 
+	9, 2, 14, 15, 2, 16, 17, 2, 
+	18, 19, 2, 21, 23, 2, 22, 20, 
+	2, 27, 25, 2, 29, 31, 2, 34, 
+	2, 2, 35, 43, 2, 36, 25, 2, 
+	38, 43, 2, 39, 43, 2, 40, 43, 
+	2, 41, 30, 2, 42, 43, 3, 21, 
 	23, 24, 4, 14, 15, 16, 17
 };
 
 static const short _json_key_offsets[] = {
-	0, 0, 12, 13, 18, 23, 28, 29,
-	30, 31, 32, 33, 34, 35, 36, 37,
-	38, 43, 44, 48, 53, 58, 63, 67,
-	71, 74, 77, 79, 83, 87, 89, 91,
-	96, 98, 100, 109, 115, 121, 127, 133,
-	135, 139, 142, 144, 146, 149, 150, 154,
-	156, 158, 160, 162, 163, 165, 167, 168,
-	170, 172, 173, 175, 177, 178, 180, 182,
-	183, 185, 187, 191, 193, 195, 196, 197,
-	198, 199, 201, 206, 208, 210, 212, 221,
-	222, 222, 222, 227, 232, 237, 238, 239,
-	240, 241, 241, 242, 243, 244, 244, 245,
-	246, 247, 247, 252, 253, 257, 262, 267,
-	272, 276, 276, 279, 282, 285, 288, 291,
+	0, 0, 12, 13, 18, 23, 28, 29, 
+	30, 31, 32, 33, 34, 35, 36, 37, 
+	38, 43, 44, 48, 53, 58, 63, 67, 
+	71, 74, 77, 79, 83, 87, 89, 91, 
+	96, 98, 100, 109, 115, 121, 127, 133, 
+	135, 139, 142, 144, 146, 149, 150, 154, 
+	156, 158, 160, 162, 163, 165, 167, 168, 
+	170, 172, 173, 175, 177, 178, 180, 182, 
+	183, 185, 187, 191, 193, 195, 196, 197, 
+	198, 199, 201, 206, 208, 210, 212, 221, 
+	222, 222, 222, 227, 232, 237, 238, 239, 
+	240, 241, 241, 242, 243, 244, 244, 245, 
+	246, 247, 247, 252, 253, 257, 262, 267, 
+	272, 276, 276, 279, 282, 285, 288, 291, 
 	294, 294, 294, 294, 294, 294
 };
 
 static const char _json_trans_keys[] = {
-	32, 34, 45, 91, 102, 110, 116, 123,
-	9, 13, 48, 57, 34, 32, 93, 125,
-	9, 13, 32, 44, 93, 9, 13, 32,
-	93, 125, 9, 13, 97, 108, 115, 101,
-	117, 108, 108, 114, 117, 101, 32, 34,
-	125, 9, 13, 34, 32, 58, 9, 13,
-	32, 93, 125, 9, 13, 32, 44, 125,
-	9, 13, 32, 44, 125, 9, 13, 32,
-	34, 9, 13, 45, 48, 49, 57, 48,
-	49, 57, 46, 69, 101, 48, 57, 69,
-	101, 48, 57, 43, 45, 48, 57, 48,
-	57, 48, 57, 46, 69, 101, 48, 57,
-	34, 92, 34, 92, 34, 47, 92, 98,
-	102, 110, 114, 116, 117, 48, 57, 65,
-	70, 97, 102, 48, 57, 65, 70, 97,
-	102, 48, 57, 65, 70, 97, 102, 48,
-	57, 65, 70, 97, 102, 34, 92, 45,
-	48, 49, 57, 48, 49, 57, 46, 115,
-	48, 57, 115, 48, 57, 34, 46, 115,
-	48, 57, 48, 57, 48, 57, 48, 57,
-	48, 57, 45, 48, 57, 48, 57, 45,
-	48, 57, 48, 57, 84, 48, 57, 48,
-	57, 58, 48, 57, 48, 57, 58, 48,
-	57, 48, 57, 43, 45, 46, 90, 48,
-	57, 48, 57, 58, 48, 48, 34, 48,
-	57, 43, 45, 90, 48, 57, 34, 44,
-	34, 44, 34, 44, 34, 45, 91, 102,
-	110, 116, 123, 48, 57, 34, 32, 93,
-	125, 9, 13, 32, 44, 93, 9, 13,
-	32, 93, 125, 9, 13, 97, 108, 115,
-	101, 117, 108, 108, 114, 117, 101, 32,
-	34, 125, 9, 13, 34, 32, 58, 9,
-	13, 32, 93, 125, 9, 13, 32, 44,
-	125, 9, 13, 32, 44, 125, 9, 13,
-	32, 34, 9, 13, 32, 9, 13, 32,
-	9, 13, 32, 9, 13, 32, 9, 13,
+	32, 34, 45, 91, 102, 110, 116, 123, 
+	9, 13, 48, 57, 34, 32, 93, 125, 
+	9, 13, 32, 44, 93, 9, 13, 32, 
+	93, 125, 9, 13, 97, 108, 115, 101, 
+	117, 108, 108, 114, 117, 101, 32, 34, 
+	125, 9, 13, 34, 32, 58, 9, 13, 
+	32, 93, 125, 9, 13, 32, 44, 125, 
+	9, 13, 32, 44, 125, 9, 13, 32, 
+	34, 9, 13, 45, 48, 49, 57, 48, 
+	49, 57, 46, 69, 101, 48, 57, 69, 
+	101, 48, 57, 43, 45, 48, 57, 48, 
+	57, 48, 57, 46, 69, 101, 48, 57, 
+	34, 92, 34, 92, 34, 47, 92, 98, 
+	102, 110, 114, 116, 117, 48, 57, 65, 
+	70, 97, 102, 48, 57, 65, 70, 97, 
+	102, 48, 57, 65, 70, 97, 102, 48, 
+	57, 65, 70, 97, 102, 34, 92, 45, 
+	48, 49, 57, 48, 49, 57, 46, 115, 
+	48, 57, 115, 48, 57, 34, 46, 115, 
+	48, 57, 48, 57, 48, 57, 48, 57, 
+	48, 57, 45, 48, 57, 48, 57, 45, 
+	48, 57, 48, 57, 84, 48, 57, 48, 
+	57, 58, 48, 57, 48, 57, 58, 48, 
+	57, 48, 57, 43, 45, 46, 90, 48, 
+	57, 48, 57, 58, 48, 48, 34, 48, 
+	57, 43, 45, 90, 48, 57, 34, 44, 
+	34, 44, 34, 44, 34, 45, 91, 102, 
+	110, 116, 123, 48, 57, 34, 32, 93, 
+	125, 9, 13, 32, 44, 93, 9, 13, 
+	32, 93, 125, 9, 13, 97, 108, 115, 
+	101, 117, 108, 108, 114, 117, 101, 32, 
+	34, 125, 9, 13, 34, 32, 58, 9, 
+	13, 32, 93, 125, 9, 13, 32, 44, 
+	125, 9, 13, 32, 44, 125, 9, 13, 
+	32, 34, 9, 13, 32, 9, 13, 32, 
+	9, 13, 32, 9, 13, 32, 9, 13, 
 	32, 9, 13, 32, 9, 13, 0
 };
 
 static const char _json_single_lengths[] = {
-	0, 8, 1, 3, 3, 3, 1, 1,
-	1, 1, 1, 1, 1, 1, 1, 1,
-	3, 1, 2, 3, 3, 3, 2, 2,
-	1, 3, 0, 2, 2, 0, 0, 3,
-	2, 2, 9, 0, 0, 0, 0, 2,
-	2, 1, 2, 0, 1, 1, 2, 0,
-	0, 0, 0, 1, 0, 0, 1, 0,
-	0, 1, 0, 0, 1, 0, 0, 1,
-	0, 0, 4, 0, 0, 1, 1, 1,
-	1, 0, 3, 2, 2, 2, 7, 1,
-	0, 0, 3, 3, 3, 1, 1, 1,
-	1, 0, 1, 1, 1, 0, 1, 1,
-	1, 0, 3, 1, 2, 3, 3, 3,
-	2, 0, 1, 1, 1, 1, 1, 1,
+	0, 8, 1, 3, 3, 3, 1, 1, 
+	1, 1, 1, 1, 1, 1, 1, 1, 
+	3, 1, 2, 3, 3, 3, 2, 2, 
+	1, 3, 0, 2, 2, 0, 0, 3, 
+	2, 2, 9, 0, 0, 0, 0, 2, 
+	2, 1, 2, 0, 1, 1, 2, 0, 
+	0, 0, 0, 1, 0, 0, 1, 0, 
+	0, 1, 0, 0, 1, 0, 0, 1, 
+	0, 0, 4, 0, 0, 1, 1, 1, 
+	1, 0, 3, 2, 2, 2, 7, 1, 
+	0, 0, 3, 3, 3, 1, 1, 1, 
+	1, 0, 1, 1, 1, 0, 1, 1, 
+	1, 0, 3, 1, 2, 3, 3, 3, 
+	2, 0, 1, 1, 1, 1, 1, 1, 
 	0, 0, 0, 0, 0, 0
 };
 
 static const char _json_range_lengths[] = {
-	0, 2, 0, 1, 1, 1, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	1, 0, 1, 1, 1, 1, 1, 1,
-	1, 0, 1, 1, 1, 1, 1, 1,
-	0, 0, 0, 3, 3, 3, 3, 0,
-	1, 1, 0, 1, 1, 0, 1, 1,
-	1, 1, 1, 0, 1, 1, 0, 1,
-	1, 0, 1, 1, 0, 1, 1, 0,
-	1, 1, 0, 1, 1, 0, 0, 0,
-	0, 1, 1, 0, 0, 0, 1, 0,
-	0, 0, 1, 1, 1, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 1, 0, 1, 1, 1, 1,
-	1, 0, 1, 1, 1, 1, 1, 1,
+	0, 2, 0, 1, 1, 1, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	1, 0, 1, 1, 1, 1, 1, 1, 
+	1, 0, 1, 1, 1, 1, 1, 1, 
+	0, 0, 0, 3, 3, 3, 3, 0, 
+	1, 1, 0, 1, 1, 0, 1, 1, 
+	1, 1, 1, 0, 1, 1, 0, 1, 
+	1, 0, 1, 1, 0, 1, 1, 0, 
+	1, 1, 0, 1, 1, 0, 0, 0, 
+	0, 1, 1, 0, 0, 0, 1, 0, 
+	0, 0, 1, 1, 1, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 1, 0, 1, 1, 1, 1, 
+	1, 0, 1, 1, 1, 1, 1, 1, 
 	0, 0, 0, 0, 0, 0
 };
 
 static const short _json_index_offsets[] = {
-	0, 0, 11, 13, 18, 23, 28, 30,
-	32, 34, 36, 38, 40, 42, 44, 46,
-	48, 53, 55, 59, 64, 69, 74, 78,
-	82, 85, 89, 91, 95, 99, 101, 103,
-	108, 111, 114, 124, 128, 132, 136, 140,
-	143, 147, 150, 153, 155, 158, 160, 164,
-	166, 168, 170, 172, 174, 176, 178, 180,
-	182, 184, 186, 188, 190, 192, 194, 196,
-	198, 200, 202, 207, 209, 211, 213, 215,
-	217, 219, 221, 226, 229, 232, 235, 244,
-	246, 247, 248, 253, 258, 263, 265, 267,
-	269, 271, 272, 274, 276, 278, 279, 281,
-	283, 285, 286, 291, 293, 297, 302, 307,
-	312, 316, 317, 320, 323, 326, 329, 332,
+	0, 0, 11, 13, 18, 23, 28, 30, 
+	32, 34, 36, 38, 40, 42, 44, 46, 
+	48, 53, 55, 59, 64, 69, 74, 78, 
+	82, 85, 89, 91, 95, 99, 101, 103, 
+	108, 111, 114, 124, 128, 132, 136, 140, 
+	143, 147, 150, 153, 155, 158, 160, 164, 
+	166, 168, 170, 172, 174, 176, 178, 180, 
+	182, 184, 186, 188, 190, 192, 194, 196, 
+	198, 200, 202, 207, 209, 211, 213, 215, 
+	217, 219, 221, 226, 229, 232, 235, 244, 
+	246, 247, 248, 253, 258, 263, 265, 267, 
+	269, 271, 272, 274, 276, 278, 279, 281, 
+	283, 285, 286, 291, 293, 297, 302, 307, 
+	312, 316, 317, 320, 323, 326, 329, 332, 
 	335, 336, 337, 338, 339, 340
 };
 
 static const unsigned char _json_indicies[] = {
-	0, 2, 3, 4, 5, 6, 7, 8,
-	0, 3, 1, 9, 1, 11, 12, 1,
-	11, 10, 13, 14, 12, 13, 1, 14,
-	1, 1, 14, 10, 15, 1, 16, 1,
-	17, 1, 18, 1, 19, 1, 20, 1,
-	21, 1, 22, 1, 23, 1, 24, 1,
-	25, 26, 27, 25, 1, 28, 1, 29,
-	30, 29, 1, 30, 1, 1, 30, 31,
-	32, 33, 34, 32, 1, 35, 36, 27,
-	35, 1, 36, 26, 36, 1, 37, 38,
-	39, 1, 38, 39, 1, 41, 42, 42,
-	40, 43, 1, 42, 42, 43, 40, 44,
-	44, 45, 1, 45, 1, 45, 40, 41,
-	42, 42, 39, 40, 47, 48, 46, 50,
-	51, 49, 52, 52, 52, 52, 52, 52,
-	52, 52, 53, 1, 54, 54, 54, 1,
-	55, 55, 55, 1, 56, 56, 56, 1,
-	57, 57, 57, 1, 59, 60, 58, 61,
-	62, 63, 1, 64, 65, 1, 66, 67,
-	1, 68, 1, 67, 68, 1, 69, 1,
-	66, 67, 65, 1, 70, 1, 71, 1,
-	72, 1, 73, 1, 74, 1, 75, 1,
-	76, 1, 77, 1, 78, 1, 79, 1,
-	80, 1, 81, 1, 82, 1, 83, 1,
-	84, 1, 85, 1, 86, 1, 87, 1,
-	88, 1, 89, 89, 90, 91, 1, 92,
-	1, 93, 1, 94, 1, 95, 1, 96,
-	1, 97, 1, 98, 1, 99, 99, 100,
-	98, 1, 102, 1, 101, 104, 105, 103,
-	1, 1, 101, 106, 107, 108, 109, 110,
-	111, 112, 107, 1, 113, 1, 114, 115,
-	117, 118, 1, 117, 116, 119, 120, 118,
-	119, 1, 120, 1, 1, 120, 116, 121,
-	1, 122, 1, 123, 1, 124, 1, 125,
-	126, 1, 127, 1, 128, 1, 129, 130,
-	1, 131, 1, 132, 1, 133, 134, 135,
-	136, 134, 1, 137, 1, 138, 139, 138,
-	1, 139, 1, 1, 139, 140, 141, 142,
-	143, 141, 1, 144, 145, 136, 144, 1,
-	145, 135, 145, 1, 146, 147, 147, 1,
-	148, 148, 1, 149, 149, 1, 150, 150,
-	1, 151, 151, 1, 152, 152, 1, 1,
+	0, 2, 3, 4, 5, 6, 7, 8, 
+	0, 3, 1, 9, 1, 11, 12, 1, 
+	11, 10, 13, 14, 12, 13, 1, 14, 
+	1, 1, 14, 10, 15, 1, 16, 1, 
+	17, 1, 18, 1, 19, 1, 20, 1, 
+	21, 1, 22, 1, 23, 1, 24, 1, 
+	25, 26, 27, 25, 1, 28, 1, 29, 
+	30, 29, 1, 30, 1, 1, 30, 31, 
+	32, 33, 34, 32, 1, 35, 36, 27, 
+	35, 1, 36, 26, 36, 1, 37, 38, 
+	39, 1, 38, 39, 1, 41, 42, 42, 
+	40, 43, 1, 42, 42, 43, 40, 44, 
+	44, 45, 1, 45, 1, 45, 40, 41, 
+	42, 42, 39, 40, 47, 48, 46, 50, 
+	51, 49, 52, 52, 52, 52, 52, 52, 
+	52, 52, 53, 1, 54, 54, 54, 1, 
+	55, 55, 55, 1, 56, 56, 56, 1, 
+	57, 57, 57, 1, 59, 60, 58, 61, 
+	62, 63, 1, 64, 65, 1, 66, 67, 
+	1, 68, 1, 67, 68, 1, 69, 1, 
+	66, 67, 65, 1, 70, 1, 71, 1, 
+	72, 1, 73, 1, 74, 1, 75, 1, 
+	76, 1, 77, 1, 78, 1, 79, 1, 
+	80, 1, 81, 1, 82, 1, 83, 1, 
+	84, 1, 85, 1, 86, 1, 87, 1, 
+	88, 1, 89, 89, 90, 91, 1, 92, 
+	1, 93, 1, 94, 1, 95, 1, 96, 
+	1, 97, 1, 98, 1, 99, 99, 100, 
+	98, 1, 102, 1, 101, 104, 105, 103, 
+	1, 1, 101, 106, 107, 108, 109, 110, 
+	111, 112, 107, 1, 113, 1, 114, 115, 
+	117, 118, 1, 117, 116, 119, 120, 118, 
+	119, 1, 120, 1, 1, 120, 116, 121, 
+	1, 122, 1, 123, 1, 124, 1, 125, 
+	126, 1, 127, 1, 128, 1, 129, 130, 
+	1, 131, 1, 132, 1, 133, 134, 135, 
+	136, 134, 1, 137, 1, 138, 139, 138, 
+	1, 139, 1, 1, 139, 140, 141, 142, 
+	143, 141, 1, 144, 145, 136, 144, 1, 
+	145, 135, 145, 1, 146, 147, 147, 1, 
+	148, 148, 1, 149, 149, 1, 150, 150, 
+	1, 151, 151, 1, 152, 152, 1, 1, 
 	1, 1, 1, 1, 1, 0
 };
 
 static const char _json_trans_targs[] = {
-	1, 0, 2, 107, 3, 6, 10, 13,
-	16, 106, 4, 3, 106, 4, 5, 7,
-	8, 9, 108, 11, 12, 109, 14, 15,
-	110, 16, 17, 111, 18, 18, 19, 20,
-	21, 22, 111, 21, 22, 24, 25, 31,
-	112, 26, 28, 27, 29, 30, 33, 113,
-	34, 33, 113, 34, 32, 35, 36, 37,
-	38, 39, 33, 113, 34, 41, 42, 46,
-	42, 46, 43, 45, 44, 114, 48, 49,
-	50, 51, 52, 53, 54, 55, 56, 57,
-	58, 59, 60, 61, 62, 63, 64, 65,
-	66, 67, 73, 72, 68, 69, 70, 71,
-	72, 115, 74, 67, 72, 76, 116, 76,
-	116, 77, 79, 81, 82, 85, 90, 94,
-	98, 80, 117, 117, 83, 82, 80, 83,
-	84, 86, 87, 88, 89, 117, 91, 92,
-	93, 117, 95, 96, 97, 117, 98, 99,
-	105, 100, 100, 101, 102, 103, 104, 105,
-	103, 104, 117, 106, 106, 106, 106, 106,
+	1, 0, 2, 107, 3, 6, 10, 13, 
+	16, 106, 4, 3, 106, 4, 5, 7, 
+	8, 9, 108, 11, 12, 109, 14, 15, 
+	110, 16, 17, 111, 18, 18, 19, 20, 
+	21, 22, 111, 21, 22, 24, 25, 31, 
+	112, 26, 28, 27, 29, 30, 33, 113, 
+	34, 33, 113, 34, 32, 35, 36, 37, 
+	38, 39, 33, 113, 34, 41, 42, 46, 
+	42, 46, 43, 45, 44, 114, 48, 49, 
+	50, 51, 52, 53, 54, 55, 56, 57, 
+	58, 59, 60, 61, 62, 63, 64, 65, 
+	66, 67, 73, 72, 68, 69, 70, 71, 
+	72, 115, 74, 67, 72, 76, 116, 76, 
+	116, 77, 79, 81, 82, 85, 90, 94, 
+	98, 80, 117, 117, 83, 82, 80, 83, 
+	84, 86, 87, 88, 89, 117, 91, 92, 
+	93, 117, 95, 96, 97, 117, 98, 99, 
+	105, 100, 100, 101, 102, 103, 104, 105, 
+	103, 104, 117, 106, 106, 106, 106, 106, 
 	106
 };
 
 static const char _json_trans_actions[] = {
-	0, 0, 92, 86, 35, 0, 0, 0,
-	104, 41, 27, 0, 37, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 80, 33, 29, 0, 0, 27,
-	31, 31, 83, 0, 0, 0, 0, 0,
-	3, 0, 0, 0, 0, 0, 5, 15,
-	0, 0, 53, 7, 13, 0, 56, 9,
-	9, 9, 59, 62, 11, 17, 17, 17,
-	0, 0, 0, 19, 0, 21, 23, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 114, 65, 114, 0, 0, 0, 0,
-	0, 71, 0, 68, 68, 77, 25, 0,
-	110, 74, 92, 86, 35, 0, 0, 0,
-	104, 41, 51, 89, 27, 0, 37, 0,
-	0, 0, 0, 0, 0, 98, 0, 0,
-	0, 101, 0, 0, 0, 95, 0, 80,
-	33, 29, 0, 0, 27, 31, 31, 83,
-	0, 0, 107, 0, 39, 45, 47, 43,
+	0, 0, 92, 86, 35, 0, 0, 0, 
+	104, 41, 27, 0, 37, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 80, 33, 29, 0, 0, 27, 
+	31, 31, 83, 0, 0, 0, 0, 0, 
+	3, 0, 0, 0, 0, 0, 5, 15, 
+	0, 0, 53, 7, 13, 0, 56, 9, 
+	9, 9, 59, 62, 11, 17, 17, 17, 
+	0, 0, 0, 19, 0, 21, 23, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 114, 65, 114, 0, 0, 0, 0, 
+	0, 71, 0, 68, 68, 77, 25, 0, 
+	110, 74, 92, 86, 35, 0, 0, 0, 
+	104, 41, 51, 89, 27, 0, 37, 0, 
+	0, 0, 0, 0, 0, 98, 0, 0, 
+	0, 101, 0, 0, 0, 95, 0, 80, 
+	33, 29, 0, 0, 27, 31, 31, 83, 
+	0, 0, 107, 0, 39, 45, 47, 43, 
 	49
 };
 
 static const char _json_eof_actions[] = {
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 1, 0, 1, 0, 0, 1, 1,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 39, 45, 47, 43, 49,
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 1, 0, 1, 0, 0, 1, 1, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 0, 0, 0, 0, 0, 
+	0, 0, 0, 39, 45, 47, 43, 49, 
 	0, 0, 0, 0, 0, 0
 };
 
@@ -15386,7 +11543,7 @@
 static const int json_en_main = 1;
 
 
-#line 2733 "upb/json/parser.rl"
+#line 2698 "upb/json/parser.rl"
 
 size_t parse(void *closure, const void *hd, const char *buf, size_t size,
              const upb_bufhandle *handle) {
@@ -15408,8 +11565,8 @@
 
   capture_resume(parser, buf);
 
-
-#line 2831 "upb/json/parser.c"
+  
+#line 2796 "upb/json/parser.c"
 	{
 	int _klen;
 	unsigned int _trans;
@@ -15484,103 +11641,103 @@
 		switch ( *_acts++ )
 		{
 	case 1:
-#line 2561 "upb/json/parser.rl"
+#line 2526 "upb/json/parser.rl"
 	{ p--; {cs = stack[--top]; goto _again;} }
 	break;
 	case 2:
-#line 2563 "upb/json/parser.rl"
+#line 2528 "upb/json/parser.rl"
 	{ p--; {stack[top++] = cs; cs = 23;goto _again;} }
 	break;
 	case 3:
-#line 2567 "upb/json/parser.rl"
+#line 2532 "upb/json/parser.rl"
 	{ start_text(parser, p); }
 	break;
 	case 4:
-#line 2568 "upb/json/parser.rl"
+#line 2533 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_text(parser, p)); }
 	break;
 	case 5:
-#line 2574 "upb/json/parser.rl"
+#line 2539 "upb/json/parser.rl"
 	{ start_hex(parser); }
 	break;
 	case 6:
-#line 2575 "upb/json/parser.rl"
+#line 2540 "upb/json/parser.rl"
 	{ hexdigit(parser, p); }
 	break;
 	case 7:
-#line 2576 "upb/json/parser.rl"
+#line 2541 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_hex(parser)); }
 	break;
 	case 8:
-#line 2582 "upb/json/parser.rl"
+#line 2547 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(escape(parser, p)); }
 	break;
 	case 9:
-#line 2588 "upb/json/parser.rl"
+#line 2553 "upb/json/parser.rl"
 	{ p--; {cs = stack[--top]; goto _again;} }
 	break;
 	case 10:
-#line 2600 "upb/json/parser.rl"
+#line 2565 "upb/json/parser.rl"
 	{ start_duration_base(parser, p); }
 	break;
 	case 11:
-#line 2601 "upb/json/parser.rl"
+#line 2566 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_duration_base(parser, p)); }
 	break;
 	case 12:
-#line 2603 "upb/json/parser.rl"
+#line 2568 "upb/json/parser.rl"
 	{ p--; {cs = stack[--top]; goto _again;} }
 	break;
 	case 13:
-#line 2608 "upb/json/parser.rl"
+#line 2573 "upb/json/parser.rl"
 	{ start_timestamp_base(parser, p); }
 	break;
 	case 14:
-#line 2609 "upb/json/parser.rl"
+#line 2574 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_timestamp_base(parser, p)); }
 	break;
 	case 15:
-#line 2611 "upb/json/parser.rl"
+#line 2576 "upb/json/parser.rl"
 	{ start_timestamp_fraction(parser, p); }
 	break;
 	case 16:
-#line 2612 "upb/json/parser.rl"
+#line 2577 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_timestamp_fraction(parser, p)); }
 	break;
 	case 17:
-#line 2614 "upb/json/parser.rl"
+#line 2579 "upb/json/parser.rl"
 	{ start_timestamp_zone(parser, p); }
 	break;
 	case 18:
-#line 2615 "upb/json/parser.rl"
+#line 2580 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_timestamp_zone(parser, p)); }
 	break;
 	case 19:
-#line 2617 "upb/json/parser.rl"
+#line 2582 "upb/json/parser.rl"
 	{ p--; {cs = stack[--top]; goto _again;} }
 	break;
 	case 20:
-#line 2622 "upb/json/parser.rl"
+#line 2587 "upb/json/parser.rl"
 	{ start_fieldmask_path_text(parser, p); }
 	break;
 	case 21:
-#line 2623 "upb/json/parser.rl"
+#line 2588 "upb/json/parser.rl"
 	{ end_fieldmask_path_text(parser, p); }
 	break;
 	case 22:
-#line 2628 "upb/json/parser.rl"
+#line 2593 "upb/json/parser.rl"
 	{ start_fieldmask_path(parser); }
 	break;
 	case 23:
-#line 2629 "upb/json/parser.rl"
+#line 2594 "upb/json/parser.rl"
 	{ end_fieldmask_path(parser); }
 	break;
 	case 24:
-#line 2635 "upb/json/parser.rl"
+#line 2600 "upb/json/parser.rl"
 	{ p--; {cs = stack[--top]; goto _again;} }
 	break;
 	case 25:
-#line 2640 "upb/json/parser.rl"
+#line 2605 "upb/json/parser.rl"
 	{
         if (is_wellknown_msg(parser, UPB_WELLKNOWN_TIMESTAMP)) {
           {stack[top++] = cs; cs = 47;goto _again;}
@@ -15594,11 +11751,11 @@
       }
 	break;
 	case 26:
-#line 2653 "upb/json/parser.rl"
+#line 2618 "upb/json/parser.rl"
 	{ p--; {stack[top++] = cs; cs = 78;goto _again;} }
 	break;
 	case 27:
-#line 2658 "upb/json/parser.rl"
+#line 2623 "upb/json/parser.rl"
 	{
         if (is_wellknown_msg(parser, UPB_WELLKNOWN_ANY)) {
           start_any_member(parser, p);
@@ -15608,11 +11765,11 @@
       }
 	break;
 	case 28:
-#line 2665 "upb/json/parser.rl"
+#line 2630 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_membername(parser)); }
 	break;
 	case 29:
-#line 2668 "upb/json/parser.rl"
+#line 2633 "upb/json/parser.rl"
 	{
         if (is_wellknown_msg(parser, UPB_WELLKNOWN_ANY)) {
           end_any_member(parser, p);
@@ -15622,7 +11779,7 @@
       }
 	break;
 	case 30:
-#line 2679 "upb/json/parser.rl"
+#line 2644 "upb/json/parser.rl"
 	{
         if (is_wellknown_msg(parser, UPB_WELLKNOWN_ANY)) {
           start_any_object(parser, p);
@@ -15632,7 +11789,7 @@
       }
 	break;
 	case 31:
-#line 2688 "upb/json/parser.rl"
+#line 2653 "upb/json/parser.rl"
 	{
         if (is_wellknown_msg(parser, UPB_WELLKNOWN_ANY)) {
           CHECK_RETURN_TOP(end_any_object(parser, p));
@@ -15642,54 +11799,54 @@
       }
 	break;
 	case 32:
-#line 2700 "upb/json/parser.rl"
+#line 2665 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(start_array(parser)); }
 	break;
 	case 33:
-#line 2704 "upb/json/parser.rl"
+#line 2669 "upb/json/parser.rl"
 	{ end_array(parser); }
 	break;
 	case 34:
-#line 2709 "upb/json/parser.rl"
+#line 2674 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(start_number(parser, p)); }
 	break;
 	case 35:
-#line 2710 "upb/json/parser.rl"
+#line 2675 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_number(parser, p)); }
 	break;
 	case 36:
-#line 2712 "upb/json/parser.rl"
+#line 2677 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(start_stringval(parser)); }
 	break;
 	case 37:
-#line 2713 "upb/json/parser.rl"
+#line 2678 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_stringval(parser)); }
 	break;
 	case 38:
-#line 2715 "upb/json/parser.rl"
+#line 2680 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_bool(parser, true)); }
 	break;
 	case 39:
-#line 2717 "upb/json/parser.rl"
+#line 2682 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_bool(parser, false)); }
 	break;
 	case 40:
-#line 2719 "upb/json/parser.rl"
+#line 2684 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_null(parser)); }
 	break;
 	case 41:
-#line 2721 "upb/json/parser.rl"
+#line 2686 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(start_subobject_full(parser)); }
 	break;
 	case 42:
-#line 2722 "upb/json/parser.rl"
+#line 2687 "upb/json/parser.rl"
 	{ end_subobject_full(parser); }
 	break;
 	case 43:
-#line 2727 "upb/json/parser.rl"
+#line 2692 "upb/json/parser.rl"
 	{ p--; {cs = stack[--top]; goto _again;} }
 	break;
-#line 3111 "upb/json/parser.c"
+#line 3076 "upb/json/parser.c"
 		}
 	}
 
@@ -15706,32 +11863,32 @@
 	while ( __nacts-- > 0 ) {
 		switch ( *__acts++ ) {
 	case 0:
-#line 2559 "upb/json/parser.rl"
+#line 2524 "upb/json/parser.rl"
 	{ p--; {cs = stack[--top]; 	if ( p == pe )
 		goto _test_eof;
 goto _again;} }
 	break;
 	case 35:
-#line 2710 "upb/json/parser.rl"
+#line 2675 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_number(parser, p)); }
 	break;
 	case 38:
-#line 2715 "upb/json/parser.rl"
+#line 2680 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_bool(parser, true)); }
 	break;
 	case 39:
-#line 2717 "upb/json/parser.rl"
+#line 2682 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_bool(parser, false)); }
 	break;
 	case 40:
-#line 2719 "upb/json/parser.rl"
+#line 2684 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_null(parser)); }
 	break;
 	case 42:
-#line 2722 "upb/json/parser.rl"
+#line 2687 "upb/json/parser.rl"
 	{ end_subobject_full(parser); }
 	break;
-#line 3153 "upb/json/parser.c"
+#line 3118 "upb/json/parser.c"
 		}
 	}
 	}
@@ -15739,11 +11896,10 @@
 	_out: {}
 	}
 
-#line 2755 "upb/json/parser.rl"
+#line 2720 "upb/json/parser.rl"
 
   if (p != pe) {
-    upb_status_seterrf(&parser->status, "Parse error at '%.*s'\n", pe - p, p);
-    upb_env_reporterror(parser->env, &parser->status);
+    upb_status_seterrf(parser->status, "Parse error at '%.*s'\n", pe - p, p);
   } else {
     capture_suspend(parser, &p);
   }
@@ -15787,124 +11943,92 @@
   p->top->is_unknown_field = false;
 
   /* Emit Ragel initialization of the parser. */
-
-#line 3210 "upb/json/parser.c"
+  
+#line 3174 "upb/json/parser.c"
 	{
 	cs = json_start;
 	top = 0;
 	}
 
-#line 2803 "upb/json/parser.rl"
+#line 2767 "upb/json/parser.rl"
   p->current_state = cs;
   p->parser_top = top;
   accumulate_clear(p);
   p->multipart_state = MULTIPART_INACTIVE;
   p->capture = NULL;
   p->accumulated = NULL;
-  upb_status_clear(&p->status);
 }
 
-static void visit_json_parsermethod(const upb_refcounted *r,
-                                    upb_refcounted_visit *visit,
-                                    void *closure) {
-  const upb_json_parsermethod *method = (upb_json_parsermethod*)r;
-  visit(r, upb_msgdef_upcast2(method->msg), closure);
-}
-
-static void free_json_parsermethod(upb_refcounted *r) {
-  upb_json_parsermethod *method = (upb_json_parsermethod*)r;
-
-  upb_inttable_iter i;
-  upb_inttable_begin(&i, &method->name_tables);
-  for(; !upb_inttable_done(&i); upb_inttable_next(&i)) {
-    upb_value val = upb_inttable_iter_value(&i);
-    upb_strtable *t = upb_value_getptr(val);
-    upb_strtable_uninit(t);
-    upb_gfree(t);
-  }
-
-  upb_inttable_uninit(&method->name_tables);
-
-  upb_gfree(r);
-}
-
-static void add_jsonname_table(upb_json_parsermethod *m, const upb_msgdef* md) {
+static upb_json_parsermethod *parsermethod_new(upb_json_codecache *c,
+                                               const upb_msgdef *md) {
   upb_msg_field_iter i;
-  upb_strtable *t;
+  upb_alloc *alloc = upb_arena_alloc(c->arena);
 
-  /* It would be nice to stack-allocate this, but protobufs do not limit the
-   * length of fields to any reasonable limit. */
-  char *buf = NULL;
-  size_t len = 0;
+  upb_json_parsermethod *m = upb_malloc(alloc, sizeof(*m));
 
-  if (upb_inttable_lookupptr(&m->name_tables, md, NULL)) {
-    return;
-  }
+  m->cache = c;
 
-  /* TODO(haberman): handle malloc failure. */
-  t = upb_gmalloc(sizeof(*t));
-  upb_strtable_init(t, UPB_CTYPE_CONSTPTR);
-  upb_inttable_insertptr(&m->name_tables, md, upb_value_ptr(t));
+  upb_byteshandler_init(&m->input_handler_);
+  upb_byteshandler_setstring(&m->input_handler_, parse, m);
+  upb_byteshandler_setendstr(&m->input_handler_, end, m);
+
+  upb_strtable_init2(&m->name_table, UPB_CTYPE_CONSTPTR, alloc);
+
+  /* Build name_table */
 
   for(upb_msg_field_begin(&i, md);
       !upb_msg_field_done(&i);
       upb_msg_field_next(&i)) {
     const upb_fielddef *f = upb_msg_iter_field(&i);
+    upb_value v = upb_value_constptr(f);
+    char *buf;
 
     /* Add an entry for the JSON name. */
-    size_t field_len = upb_fielddef_getjsonname(f, buf, len);
-    if (field_len > len) {
-      size_t len2;
-      buf = upb_grealloc(buf, 0, field_len);
-      len = field_len;
-      len2 = upb_fielddef_getjsonname(f, buf, len);
-      UPB_ASSERT(len == len2);
-    }
-    upb_strtable_insert(t, buf, upb_value_constptr(f));
+    size_t len = upb_fielddef_getjsonname(f, NULL, 0);
+    buf = upb_malloc(alloc, len);
+    upb_fielddef_getjsonname(f, buf, len);
+    upb_strtable_insert3(&m->name_table, buf, strlen(buf), v, alloc);
 
     if (strcmp(buf, upb_fielddef_name(f)) != 0) {
       /* Since the JSON name is different from the regular field name, add an
        * entry for the raw name (compliant proto3 JSON parsers must accept
        * both). */
-      upb_strtable_insert(t, upb_fielddef_name(f), upb_value_constptr(f));
-    }
-
-    if (upb_fielddef_issubmsg(f)) {
-      add_jsonname_table(m, upb_fielddef_msgsubdef(f));
+      const char *name = upb_fielddef_name(f);
+      upb_strtable_insert3(&m->name_table, name, strlen(name), v, alloc);
     }
   }
 
-  upb_gfree(buf);
+  return m;
 }
 
 /* Public API *****************************************************************/
 
-upb_json_parser *upb_json_parser_create(upb_env *env,
+upb_json_parser *upb_json_parser_create(upb_arena *arena,
                                         const upb_json_parsermethod *method,
                                         const upb_symtab* symtab,
-                                        upb_sink *output,
+                                        upb_sink output,
+                                        upb_status *status,
                                         bool ignore_json_unknown) {
 #ifndef NDEBUG
-  const size_t size_before = upb_env_bytesallocated(env);
+  const size_t size_before = upb_arena_bytesallocated(arena);
 #endif
-  upb_json_parser *p = upb_env_malloc(env, sizeof(upb_json_parser));
+  upb_json_parser *p = upb_arena_malloc(arena, sizeof(upb_json_parser));
   if (!p) return false;
 
-  p->env = env;
+  p->arena = arena;
   p->method = method;
+  p->status = status;
   p->limit = p->stack + UPB_JSON_MAX_DEPTH;
   p->accumulate_buf = NULL;
   p->accumulate_buf_size = 0;
   upb_bytessink_reset(&p->input_, &method->input_handler_, p);
 
   json_parser_reset(p);
-  upb_sink_reset(&p->top->sink, output->handlers, output->closure);
-  p->top->m = upb_handlers_msgdef(output->handlers);
+  p->top->sink = output;
+  p->top->m = upb_handlers_msgdef(output.handlers);
   if (is_wellknown_msg(p, UPB_WELLKNOWN_ANY)) {
     p->top->is_any = true;
-    p->top->any_frame =
-        upb_env_malloc(p->env, sizeof(upb_jsonparser_any_frame));
-    json_parser_any_frame_reset(p->top->any_frame);
+    p->top->any_frame = json_parser_any_frame_new(p);
   } else {
     p->top->is_any = false;
     p->top->any_frame = NULL;
@@ -15915,56 +12039,91 @@
   p->ignore_json_unknown = ignore_json_unknown;
 
   /* If this fails, uncomment and increase the value in parser.h. */
-  /* fprintf(stderr, "%zd\n", upb_env_bytesallocated(env) - size_before); */
-  UPB_ASSERT_DEBUGVAR(upb_env_bytesallocated(env) - size_before <=
+  /* fprintf(stderr, "%zd\n", upb_arena_bytesallocated(arena) - size_before); */
+  UPB_ASSERT_DEBUGVAR(upb_arena_bytesallocated(arena) - size_before <=
                       UPB_JSON_PARSER_SIZE);
   return p;
 }
 
-upb_bytessink *upb_json_parser_input(upb_json_parser *p) {
-  return &p->input_;
-}
-
-upb_json_parsermethod *upb_json_parsermethod_new(const upb_msgdef* md,
-                                                 const void* owner) {
-  static const struct upb_refcounted_vtbl vtbl = {visit_json_parsermethod,
-                                                  free_json_parsermethod};
-  upb_json_parsermethod *ret = upb_gmalloc(sizeof(*ret));
-  upb_refcounted_init(upb_json_parsermethod_upcast_mutable(ret), &vtbl, owner);
-
-  ret->msg = md;
-  upb_ref2(md, ret);
-
-  upb_byteshandler_init(&ret->input_handler_);
-  upb_byteshandler_setstring(&ret->input_handler_, parse, ret);
-  upb_byteshandler_setendstr(&ret->input_handler_, end, ret);
-
-  upb_inttable_init(&ret->name_tables, UPB_CTYPE_PTR);
-
-  add_jsonname_table(ret, md);
-
-  return ret;
+upb_bytessink upb_json_parser_input(upb_json_parser *p) {
+  return p->input_;
 }
 
 const upb_byteshandler *upb_json_parsermethod_inputhandler(
     const upb_json_parsermethod *m) {
   return &m->input_handler_;
 }
+
+upb_json_codecache *upb_json_codecache_new() {
+  upb_alloc *alloc;
+  upb_json_codecache *c;
+
+  c = upb_gmalloc(sizeof(*c));
+
+  c->arena = upb_arena_new();
+  alloc = upb_arena_alloc(c->arena);
+
+  upb_inttable_init2(&c->methods, UPB_CTYPE_CONSTPTR, alloc);
+
+  return c;
+}
+
+void upb_json_codecache_free(upb_json_codecache *c) {
+  upb_arena_free(c->arena);
+  upb_gfree(c);
+}
+
+const upb_json_parsermethod *upb_json_codecache_get(upb_json_codecache *c,
+                                                    const upb_msgdef *md) {
+  upb_json_parsermethod *m;
+  upb_value v;
+  upb_msg_field_iter i;
+  upb_alloc *alloc = upb_arena_alloc(c->arena);
+
+  if (upb_inttable_lookupptr(&c->methods, md, &v)) {
+    return upb_value_getconstptr(v);
+  }
+
+  m = parsermethod_new(c, md);
+  v = upb_value_constptr(m);
+
+  if (!m) return NULL;
+  if (!upb_inttable_insertptr2(&c->methods, md, v, alloc)) return NULL;
+
+  /* Populate parser methods for all submessages, so the name tables will
+   * be available during parsing. */
+  for(upb_msg_field_begin(&i, md);
+      !upb_msg_field_done(&i);
+      upb_msg_field_next(&i)) {
+    upb_fielddef *f = upb_msg_iter_field(&i);
+
+    if (upb_fielddef_issubmsg(f)) {
+      const upb_msgdef *subdef = upb_fielddef_msgsubdef(f);
+      const upb_json_parsermethod *sub_method =
+          upb_json_codecache_get(c, subdef);
+
+      if (!sub_method) return NULL;
+    }
+  }
+
+  return m;
+}
 /*
 ** This currently uses snprintf() to format primitives, and could be optimized
 ** further.
 */
 
 
-#include <string.h>
+#include <ctype.h>
 #include <stdint.h>
+#include <string.h>
 #include <time.h>
 
 struct upb_json_printer {
   upb_sink input_;
   /* BytesSink closure. */
   void *subc_;
-  upb_bytessink *output_;
+  upb_bytessink output_;
 
   /* We track the depth so that we know when to emit startstr/endstr on the
    * output. */
@@ -15999,6 +12158,10 @@
   upb_gfree(pc);
 }
 
+typedef struct {
+  bool preserve_fieldnames;
+} upb_json_printercache;
+
 /* Convert fielddef name to JSON name and return as a string piece. */
 strpc *newstrpc(upb_handlers *h, const upb_fielddef *f,
                 bool preserve_fieldnames) {
@@ -16545,10 +12708,10 @@
                         bool preserve_fieldnames,
                         upb_handlerattr *attr) {
   EnumHandlerData *hd = upb_gmalloc(sizeof(EnumHandlerData));
-  hd->enumdef = (const upb_enumdef *)upb_fielddef_subdef(f);
+  hd->enumdef = upb_fielddef_enumsubdef(f);
   hd->keyname = newstrpc(h, f, preserve_fieldnames);
   upb_handlers_addcleanup(h, hd, upb_gfree);
-  upb_handlerattr_sethandlerdata(attr, hd);
+  attr->handler_data = hd;
 }
 
 /* Set up handlers for a mapentry submessage (i.e., an individual key/value pair
@@ -16573,7 +12736,7 @@
   const upb_fielddef* key_field = upb_msgdef_itof(md, UPB_MAPENTRY_KEY);
   const upb_fielddef* value_field = upb_msgdef_itof(md, UPB_MAPENTRY_VALUE);
 
-  upb_handlerattr empty_attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
 
   UPB_UNUSED(closure);
 
@@ -16637,10 +12800,9 @@
       upb_handlers_setstring(h, value_field, putbytes, &empty_attr);
       break;
     case UPB_TYPE_ENUM: {
-      upb_handlerattr enum_attr = UPB_HANDLERATTR_INITIALIZER;
+      upb_handlerattr enum_attr = UPB_HANDLERATTR_INIT;
       set_enum_hd(h, value_field, preserve_fieldnames, &enum_attr);
       upb_handlers_setint32(h, value_field, mapvalue_enum, &enum_attr);
-      upb_handlerattr_uninit(&enum_attr);
       break;
     }
     case UPB_TYPE_MESSAGE:
@@ -16648,8 +12810,6 @@
        * as appropriate. */
       break;
   }
-
-  upb_handlerattr_uninit(&empty_attr);
 }
 
 static bool putseconds(void *closure, const void *handler_data,
@@ -16703,7 +12863,6 @@
   UPB_UNUSED(handler_data);
   p->depth_++;
   p->first_elem_[p->depth_] = true;
-  print_data(p, "\"", 1);
   return closure;
 }
 
@@ -16711,7 +12870,6 @@
   upb_json_printer *p = closure;
   UPB_UNUSED(handler_data);
   p->depth_--;
-  print_data(p, "\"", 1);
   return true;
 }
 
@@ -16931,6 +13089,29 @@
   return true;
 }
 
+static bool printer_startmsg_fieldmask(
+    void *closure, const void *handler_data) {
+  upb_json_printer *p = closure;
+  UPB_UNUSED(handler_data);
+  if (p->depth_ == 0) {
+    upb_bytessink_start(p->output_, 0, &p->subc_);
+  }
+  print_data(p, "\"", 1);
+  return true;
+}
+
+static bool printer_endmsg_fieldmask(
+    void *closure, const void *handler_data, upb_status *s) {
+  upb_json_printer *p = closure;
+  UPB_UNUSED(handler_data);
+  UPB_UNUSED(s);
+  print_data(p, "\"", 1);
+  if (p->depth_ == 0) {
+    upb_bytessink_end(p->output_);
+  }
+  return true;
+}
+
 static void *scalar_startstr_onlykey(
     void *closure, const void *handler_data, size_t size_hint) {
   upb_json_printer *p = closure;
@@ -16946,16 +13127,16 @@
   const upb_fielddef* type_field = upb_msgdef_itof(md, UPB_ANY_TYPE);
   const upb_fielddef* value_field = upb_msgdef_itof(md, UPB_ANY_VALUE);
 
-  upb_handlerattr empty_attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
 
   /* type_url's json name is "@type" */
-  upb_handlerattr type_name_attr = UPB_HANDLERATTR_INITIALIZER;
-  upb_handlerattr value_name_attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr type_name_attr = UPB_HANDLERATTR_INIT;
+  upb_handlerattr value_name_attr = UPB_HANDLERATTR_INIT;
   strpc *type_url_json_name = newstrpc_str(h, "@type");
   strpc *value_json_name = newstrpc_str(h, "value");
 
-  upb_handlerattr_sethandlerdata(&type_name_attr, type_url_json_name);
-  upb_handlerattr_sethandlerdata(&value_name_attr, value_json_name);
+  type_name_attr.handler_data = type_url_json_name;
+  value_name_attr.handler_data = value_json_name;
 
   /* Set up handlers. */
   upb_handlers_setstartmsg(h, printer_startmsg, &empty_attr);
@@ -16979,13 +13160,13 @@
   const upb_msgdef *md = upb_handlers_msgdef(h);
   const upb_fielddef* f = upb_msgdef_itof(md, 1);
 
-  upb_handlerattr empty_attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
 
   upb_handlers_setstartseq(h, f, startseq_fieldmask, &empty_attr);
   upb_handlers_setendseq(h, f, endseq_fieldmask, &empty_attr);
 
-  upb_handlers_setstartmsg(h, printer_startmsg_noframe, &empty_attr);
-  upb_handlers_setendmsg(h, printer_endmsg_noframe, &empty_attr);
+  upb_handlers_setstartmsg(h, printer_startmsg_fieldmask, &empty_attr);
+  upb_handlers_setendmsg(h, printer_endmsg_fieldmask, &empty_attr);
 
   upb_handlers_setstartstr(h, f, repeated_startstr_fieldmask, &empty_attr);
   upb_handlers_setstring(h, f, repeated_str_fieldmask, &empty_attr);
@@ -17002,7 +13183,7 @@
   const upb_fielddef* nanos_field =
       upb_msgdef_itof(md, UPB_DURATION_NANOS);
 
-  upb_handlerattr empty_attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
 
   upb_handlers_setstartmsg(h, printer_startdurationmsg, &empty_attr);
   upb_handlers_setint64(h, seconds_field, putseconds, &empty_attr);
@@ -17022,7 +13203,7 @@
   const upb_fielddef* nanos_field =
       upb_msgdef_itof(md, UPB_TIMESTAMP_NANOS);
 
-  upb_handlerattr empty_attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
 
   upb_handlers_setstartmsg(h, printer_starttimestampmsg, &empty_attr);
   upb_handlers_setint64(h, seconds_field, putseconds, &empty_attr);
@@ -17036,7 +13217,7 @@
   const upb_msgdef *md = upb_handlers_msgdef(h);
   upb_msg_field_iter i;
 
-  upb_handlerattr empty_attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
 
   upb_handlers_setstartmsg(h, printer_startmsg_noframe, &empty_attr);
   upb_handlers_setendmsg(h, printer_endmsg_noframe, &empty_attr);
@@ -17075,7 +13256,7 @@
 void printer_sethandlers_##wrapper(const void *closure, upb_handlers *h) { \
   const upb_msgdef *md = upb_handlers_msgdef(h);                           \
   const upb_fielddef* f = upb_msgdef_itof(md, 1);                          \
-  upb_handlerattr empty_attr = UPB_HANDLERATTR_INITIALIZER;                \
+  upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;                \
   upb_handlers_setstartmsg(h, printer_startmsg_noframe, &empty_attr);      \
   upb_handlers_setendmsg(h, printer_endmsg_noframe, &empty_attr);          \
   upb_handlers_set##type(h, f, putmethod, &empty_attr);                    \
@@ -17098,7 +13279,7 @@
   const upb_msgdef *md = upb_handlers_msgdef(h);
   const upb_fielddef* f = upb_msgdef_itof(md, 1);
 
-  upb_handlerattr empty_attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
 
   upb_handlers_setstartseq(h, f, startseq_nokey, &empty_attr);
   upb_handlers_setendseq(h, f, endseq, &empty_attr);
@@ -17115,7 +13296,7 @@
   const upb_msgdef *md = upb_handlers_msgdef(h);
   const upb_fielddef* f = upb_msgdef_itof(md, 1);
 
-  upb_handlerattr empty_attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
 
   upb_handlers_setstartseq(h, f, startmap_nokey, &empty_attr);
   upb_handlers_setendseq(h, f, endmap, &empty_attr);
@@ -17131,10 +13312,10 @@
 void printer_sethandlers(const void *closure, upb_handlers *h) {
   const upb_msgdef *md = upb_handlers_msgdef(h);
   bool is_mapentry = upb_msgdef_mapentry(md);
-  upb_handlerattr empty_attr = UPB_HANDLERATTR_INITIALIZER;
+  upb_handlerattr empty_attr = UPB_HANDLERATTR_INIT;
   upb_msg_field_iter i;
-  const bool *preserve_fieldnames_ptr = closure;
-  const bool preserve_fieldnames = *preserve_fieldnames_ptr;
+  const upb_json_printercache *cache = closure;
+  const bool preserve_fieldnames = cache->preserve_fieldnames;
 
   if (is_mapentry) {
     /* mapentry messages are sufficiently different that we handle them
@@ -17201,9 +13382,8 @@
   for(; !upb_msg_field_done(&i); upb_msg_field_next(&i)) {
     const upb_fielddef *f = upb_msg_iter_field(&i);
 
-    upb_handlerattr name_attr = UPB_HANDLERATTR_INITIALIZER;
-    upb_handlerattr_sethandlerdata(&name_attr,
-                                   newstrpc(h, f, preserve_fieldnames));
+    upb_handlerattr name_attr = UPB_HANDLERATTR_INIT;
+    name_attr.handler_data = newstrpc(h, f, preserve_fieldnames);
 
     if (upb_fielddef_ismap(f)) {
       upb_handlers_setstartseq(h, f, startmap, &name_attr);
@@ -17225,7 +13405,7 @@
         /* For now, we always emit symbolic names for enums. We may want an
          * option later to control this behavior, but we will wait for a real
          * need first. */
-        upb_handlerattr enum_attr = UPB_HANDLERATTR_INITIALIZER;
+        upb_handlerattr enum_attr = UPB_HANDLERATTR_INIT;
         set_enum_hd(h, f, preserve_fieldnames, &enum_attr);
 
         if (upb_fielddef_isseq(f)) {
@@ -17234,7 +13414,6 @@
           upb_handlers_setint32(h, f, scalar_enum, &enum_attr);
         }
 
-        upb_handlerattr_uninit(&enum_attr);
         break;
       }
       case UPB_TYPE_STRING:
@@ -17265,11 +13444,8 @@
         }
         break;
     }
-
-    upb_handlerattr_uninit(&name_attr);
   }
 
-  upb_handlerattr_uninit(&empty_attr);
 #undef TYPE
 }
 
@@ -17280,13 +13456,13 @@
 
 /* Public API *****************************************************************/
 
-upb_json_printer *upb_json_printer_create(upb_env *e, const upb_handlers *h,
-                                          upb_bytessink *output) {
+upb_json_printer *upb_json_printer_create(upb_arena *a, const upb_handlers *h,
+                                          upb_bytessink output) {
 #ifndef NDEBUG
-  size_t size_before = upb_env_bytesallocated(e);
+  size_t size_before = upb_arena_bytesallocated(a);
 #endif
 
-  upb_json_printer *p = upb_env_malloc(e, sizeof(upb_json_printer));
+  upb_json_printer *p = upb_arena_malloc(a, sizeof(upb_json_printer));
   if (!p) return NULL;
 
   p->output_ = output;
@@ -17296,20 +13472,23 @@
   p->nanos = 0;
 
   /* If this fails, increase the value in printer.h. */
-  UPB_ASSERT_DEBUGVAR(upb_env_bytesallocated(e) - size_before <=
+  UPB_ASSERT_DEBUGVAR(upb_arena_bytesallocated(a) - size_before <=
                       UPB_JSON_PRINTER_SIZE);
   return p;
 }
 
-upb_sink *upb_json_printer_input(upb_json_printer *p) {
-  return &p->input_;
+upb_sink upb_json_printer_input(upb_json_printer *p) {
+  return p->input_;
 }
 
-const upb_handlers *upb_json_printer_newhandlers(const upb_msgdef *md,
-                                                 bool preserve_fieldnames,
-                                                 const void *owner) {
-  return upb_handlers_newfrozen(
-      md, owner, printer_sethandlers, &preserve_fieldnames);
+upb_handlercache *upb_json_printer_newcache(bool preserve_proto_fieldnames) {
+  upb_json_printercache *cache = upb_gmalloc(sizeof(*cache));
+  upb_handlercache *ret = upb_handlercache_new(printer_sethandlers, cache);
+
+  cache->preserve_fieldnames = preserve_proto_fieldnames;
+  upb_handlercache_addcleanup(ret, cache, upb_gfree);
+
+  return ret;
 }
 
 #undef UPB_SIZE
diff --git a/ruby/ext/google/protobuf_c/upb.h b/ruby/ext/google/protobuf_c/upb.h
index 9112aba..0c44a0b 100644
--- a/ruby/ext/google/protobuf_c/upb.h
+++ b/ruby/ext/google/protobuf_c/upb.h
@@ -1,4 +1,8 @@
-// Amalgamated source file
+/* Amalgamated source file */
+#include <stdint.h>
+#ifndef UINTPTR_MAX
+#error must include stdint.h first
+#endif
 
 #if UINTPTR_MAX == 0xffffffff
 #define UPB_SIZE(size32, size64) size32
@@ -40,69 +44,6 @@
 #ifndef UPB_MSG_H_
 #define UPB_MSG_H_
 
-/*
-** Defs are upb's internal representation of the constructs that can appear
-** in a .proto file:
-**
-** - upb::MessageDef (upb_msgdef): describes a "message" construct.
-** - upb::FieldDef (upb_fielddef): describes a message field.
-** - upb::FileDef (upb_filedef): describes a .proto file and its defs.
-** - upb::EnumDef (upb_enumdef): describes an enum.
-** - upb::OneofDef (upb_oneofdef): describes a oneof.
-** - upb::Def (upb_def): base class of all the others.
-**
-** TODO: definitions of services.
-**
-** Like upb_refcounted objects, defs are mutable only until frozen, and are
-** only thread-safe once frozen.
-**
-** This is a mixed C/C++ interface that offers a full API to both languages.
-** See the top-level README for more information.
-*/
-
-#ifndef UPB_DEF_H_
-#define UPB_DEF_H_
-
-/*
-** upb::RefCounted (upb_refcounted)
-**
-** A refcounting scheme that supports circular refs.  It accomplishes this by
-** partitioning the set of objects into groups such that no cycle spans groups;
-** we can then reference-count the group as a whole and ignore refs within the
-** group.  When objects are mutable, these groups are computed very
-** conservatively; we group any objects that have ever had a link between them.
-** When objects are frozen, we compute strongly-connected components which
-** allows us to be precise and only group objects that are actually cyclic.
-**
-** This is a mixed C/C++ interface that offers a full API to both languages.
-** See the top-level README for more information.
-*/
-
-#ifndef UPB_REFCOUNTED_H_
-#define UPB_REFCOUNTED_H_
-
-/*
-** upb_table
-**
-** This header is INTERNAL-ONLY!  Its interfaces are not public or stable!
-** This file defines very fast int->upb_value (inttable) and string->upb_value
-** (strtable) hash tables.
-**
-** The table uses chained scatter with Brent's variation (inspired by the Lua
-** implementation of hash tables).  The hash function for strings is Austin
-** Appleby's "MurmurHash."
-**
-** The inttable uses uintptr_t as its key, which guarantees it can be used to
-** store pointers or integers of at least 32 bits (upb isn't really useful on
-** systems where sizeof(void*) < 4).
-**
-** The table must be homogenous (all values of the same type).  In debug
-** mode, we check this on insert and lookup.
-*/
-
-#ifndef UPB_TABLE_H_
-#define UPB_TABLE_H_
-
 #include <stdint.h>
 #include <string.h>
 /*
@@ -119,16 +60,14 @@
 #include <stdarg.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include <stdint.h>
 
 #ifdef __cplusplus
+#include <memory>
 namespace upb {
-class Allocator;
 class Arena;
-class Environment;
-class ErrorSpace;
 class Status;
 template <int N> class InlinedArena;
-template <int N> class InlinedEnvironment;
 }
 #endif
 
@@ -180,127 +119,14 @@
 #error Need implementations of [v]snprintf and va_copy
 #endif
 
-
-#if ((defined(__cplusplus) && __cplusplus >= 201103L) || \
-      defined(__GXX_EXPERIMENTAL_CXX0X__)) && !defined(UPB_NO_CXX11)
-#define UPB_CXX11
-#endif
-
-/* UPB_DISALLOW_COPY_AND_ASSIGN()
- * UPB_DISALLOW_POD_OPS()
- *
- * Declare these in the "private" section of a C++ class to forbid copy/assign
- * or all POD ops (construct, destruct, copy, assign) on that class. */
-#ifdef UPB_CXX11
-#include <type_traits>
-#define UPB_DISALLOW_COPY_AND_ASSIGN(class_name) \
-  class_name(const class_name&) = delete; \
-  void operator=(const class_name&) = delete;
-#define UPB_DISALLOW_POD_OPS(class_name, full_class_name) \
-  class_name() = delete; \
-  ~class_name() = delete; \
-  UPB_DISALLOW_COPY_AND_ASSIGN(class_name)
-#define UPB_ASSERT_STDLAYOUT(type) \
-  static_assert(std::is_standard_layout<type>::value, \
-                #type " must be standard layout");
-#define UPB_FINAL final
-#else  /* !defined(UPB_CXX11) */
-#define UPB_DISALLOW_COPY_AND_ASSIGN(class_name) \
-  class_name(const class_name&); \
-  void operator=(const class_name&);
-#define UPB_DISALLOW_POD_OPS(class_name, full_class_name) \
-  class_name(); \
-  ~class_name(); \
-  UPB_DISALLOW_COPY_AND_ASSIGN(class_name)
-#define UPB_ASSERT_STDLAYOUT(type)
-#define UPB_FINAL
-#endif
-
-/* UPB_DECLARE_TYPE()
- * UPB_DECLARE_DERIVED_TYPE()
- * UPB_DECLARE_DERIVED_TYPE2()
- *
- * Macros for declaring C and C++ types both, including inheritance.
- * The inheritance doesn't use real C++ inheritance, to stay compatible with C.
- *
- * These macros also provide upcasts:
- *  - in C: types-specific functions (ie. upb_foo_upcast(foo))
- *  - in C++: upb::upcast(foo) along with implicit conversions
- *
- * Downcasts are not provided, but upb/def.h defines downcasts for upb::Def. */
-
-#define UPB_C_UPCASTS(ty, base)                                      \
-  UPB_INLINE base *ty ## _upcast_mutable(ty *p) { return (base*)p; } \
-  UPB_INLINE const base *ty ## _upcast(const ty *p) { return (const base*)p; }
-
-#define UPB_C_UPCASTS2(ty, base, base2)                                 \
-  UPB_C_UPCASTS(ty, base)                                               \
-  UPB_INLINE base2 *ty ## _upcast2_mutable(ty *p) { return (base2*)p; } \
-  UPB_INLINE const base2 *ty ## _upcast2(const ty *p) { return (const base2*)p; }
-
 #ifdef __cplusplus
-
-#define UPB_BEGIN_EXTERN_C extern "C" {
-#define UPB_END_EXTERN_C }
-#define UPB_PRIVATE_FOR_CPP private:
-#define UPB_DECLARE_TYPE(cppname, cname) typedef cppname cname;
-
-#define UPB_DECLARE_DERIVED_TYPE(cppname, cppbase, cname, cbase)  \
-  UPB_DECLARE_TYPE(cppname, cname)                                \
-  UPB_C_UPCASTS(cname, cbase)                                     \
-  namespace upb {                                                 \
-  template <>                                                     \
-  class Pointer<cppname> : public PointerBase<cppname, cppbase> { \
-   public:                                                        \
-    explicit Pointer(cppname* ptr)                                \
-        : PointerBase<cppname, cppbase>(ptr) {}                   \
-  };                                                              \
-  template <>                                                     \
-  class Pointer<const cppname>                                    \
-      : public PointerBase<const cppname, const cppbase> {        \
-   public:                                                        \
-    explicit Pointer(const cppname* ptr)                          \
-        : PointerBase<const cppname, const cppbase>(ptr) {}       \
-  };                                                              \
-  }
-
-#define UPB_DECLARE_DERIVED_TYPE2(cppname, cppbase, cppbase2, cname, cbase,  \
-                                  cbase2)                                    \
-  UPB_DECLARE_TYPE(cppname, cname)                                           \
-  UPB_C_UPCASTS2(cname, cbase, cbase2)                                       \
-  namespace upb {                                                            \
-  template <>                                                                \
-  class Pointer<cppname> : public PointerBase2<cppname, cppbase, cppbase2> { \
-   public:                                                                   \
-    explicit Pointer(cppname* ptr)                                           \
-        : PointerBase2<cppname, cppbase, cppbase2>(ptr) {}                   \
-  };                                                                         \
-  template <>                                                                \
-  class Pointer<const cppname>                                               \
-      : public PointerBase2<const cppname, const cppbase, const cppbase2> {  \
-   public:                                                                   \
-    explicit Pointer(const cppname* ptr)                                     \
-        : PointerBase2<const cppname, const cppbase, const cppbase2>(ptr) {} \
-  };                                                                         \
-  }
-
-#else  /* !defined(__cplusplus) */
-
-#define UPB_BEGIN_EXTERN_C
-#define UPB_END_EXTERN_C
-#define UPB_PRIVATE_FOR_CPP
-#define UPB_DECLARE_TYPE(cppname, cname) \
-  struct cname;                          \
-  typedef struct cname cname;
-#define UPB_DECLARE_DERIVED_TYPE(cppname, cppbase, cname, cbase) \
-  UPB_DECLARE_TYPE(cppname, cname)                               \
-  UPB_C_UPCASTS(cname, cbase)
-#define UPB_DECLARE_DERIVED_TYPE2(cppname, cppbase, cppbase2,    \
-                                  cname, cbase, cbase2)          \
-  UPB_DECLARE_TYPE(cppname, cname)                               \
-  UPB_C_UPCASTS2(cname, cbase, cbase2)
-
-#endif  /* defined(__cplusplus) */
+#if __cplusplus >= 201103L || defined(__GXX_EXPERIMENTAL_CXX0X__) || \
+    (defined(_MSC_VER) && _MSC_VER >= 1900)
+// C++11 is present
+#else
+#error upb requires C++11 for C++ support
+#endif
+#endif
 
 #define UPB_MAX(x, y) ((x) > (y) ? (x) : (y))
 #define UPB_MIN(x, y) ((x) < (y) ? (x) : (y))
@@ -325,135 +151,26 @@
 #define UPB_UNREACHABLE() do { assert(0); } while(0)
 #endif
 
-/* Generic function type. */
-typedef void upb_func();
+/* upb_status *****************************************************************/
 
-
-/* C++ Casts ******************************************************************/
-
-#ifdef __cplusplus
-
-namespace upb {
-
-template <class T> class Pointer;
-
-/* Casts to a subclass.  The caller must know that cast is correct; an
- * incorrect cast will throw an assertion failure in debug mode.
- *
- * Example:
- *   upb::Def* def = GetDef();
- *   // Assert-fails if this was not actually a MessageDef.
- *   upb::MessgeDef* md = upb::down_cast<upb::MessageDef>(def);
- *
- * Note that downcasts are only defined for some types (at the moment you can
- * only downcast from a upb::Def to a specific Def type). */
-template<class To, class From> To down_cast(From* f);
-
-/* Casts to a subclass.  If the class does not actually match the given To type,
- * returns NULL.
- *
- * Example:
- *   upb::Def* def = GetDef();
- *   // md will be NULL if this was not actually a MessageDef.
- *   upb::MessgeDef* md = upb::down_cast<upb::MessageDef>(def);
- *
- * Note that dynamic casts are only defined for some types (at the moment you
- * can only downcast from a upb::Def to a specific Def type).. */
-template<class To, class From> To dyn_cast(From* f);
-
-/* Casts to any base class, or the type itself (ie. can be a no-op).
- *
- * Example:
- *   upb::MessageDef* md = GetDef();
- *   // This will fail to compile if this wasn't actually a base class.
- *   upb::Def* def = upb::upcast(md);
- */
-template <class T> inline Pointer<T> upcast(T *f) { return Pointer<T>(f); }
-
-/* Attempt upcast to specific base class.
- *
- * Example:
- *   upb::MessageDef* md = GetDef();
- *   upb::upcast_to<upb::Def>(md)->MethodOnDef();
- */
-template <class T, class F> inline T* upcast_to(F *f) {
-  return static_cast<T*>(upcast(f));
-}
-
-/* PointerBase<T>: implementation detail of upb::upcast().
- * It is implicitly convertable to pointers to the Base class(es).
- */
-template <class T, class Base>
-class PointerBase {
- public:
-  explicit PointerBase(T* ptr) : ptr_(ptr) {}
-  operator T*() { return ptr_; }
-  operator Base*() { return (Base*)ptr_; }
-
- private:
-  T* ptr_;
-};
-
-template <class T, class Base, class Base2>
-class PointerBase2 : public PointerBase<T, Base> {
- public:
-  explicit PointerBase2(T* ptr) : PointerBase<T, Base>(ptr) {}
-  operator Base2*() { return Pointer<Base>(*this); }
-};
-
-}
-
-#endif
-
-/* A list of types as they are encoded on-the-wire. */
-typedef enum {
-  UPB_WIRE_TYPE_VARINT      = 0,
-  UPB_WIRE_TYPE_64BIT       = 1,
-  UPB_WIRE_TYPE_DELIMITED   = 2,
-  UPB_WIRE_TYPE_START_GROUP = 3,
-  UPB_WIRE_TYPE_END_GROUP   = 4,
-  UPB_WIRE_TYPE_32BIT       = 5
-} upb_wiretype_t;
-
-
-/* upb::ErrorSpace ************************************************************/
-
-/* A upb::ErrorSpace represents some domain of possible error values.  This lets
- * upb::Status attach specific error codes to operations, like POSIX/C errno,
- * Win32 error codes, etc.  Clients who want to know the very specific error
- * code can check the error space and then know the type of the integer code.
- *
- * NOTE: upb::ErrorSpace is currently not used and should be considered
- * experimental.  It is important primarily in cases where upb is performing
- * I/O, but upb doesn't currently have any components that do this. */
-
-UPB_DECLARE_TYPE(upb::ErrorSpace, upb_errorspace)
-
-#ifdef __cplusplus
-class upb::ErrorSpace {
-#else
-struct upb_errorspace {
-#endif
-  const char *name;
-};
-
-
-/* upb::Status ****************************************************************/
-
-/* upb::Status represents a success or failure status and error message.
+/* upb_status represents a success or failure status and error message.
  * It owns no resources and allocates no memory, so it should work
  * even in OOM situations. */
-UPB_DECLARE_TYPE(upb::Status, upb_status)
 
 /* The maximum length of an error message before it will get truncated. */
-#define UPB_STATUS_MAX_MESSAGE 128
+#define UPB_STATUS_MAX_MESSAGE 127
 
-UPB_BEGIN_EXTERN_C
+typedef struct {
+  bool ok;
+  char msg[UPB_STATUS_MAX_MESSAGE];  /* Error message; NULL-terminated. */
+} upb_status;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 const char *upb_status_errmsg(const upb_status *status);
 bool upb_ok(const upb_status *status);
-upb_errorspace *upb_status_errspace(const upb_status *status);
-int upb_status_errcode(const upb_status *status);
 
 /* Any of the functions that write to a status object allow status to be NULL,
  * to support use cases where the function's caller does not care about the
@@ -462,88 +179,55 @@
 void upb_status_seterrmsg(upb_status *status, const char *msg);
 void upb_status_seterrf(upb_status *status, const char *fmt, ...);
 void upb_status_vseterrf(upb_status *status, const char *fmt, va_list args);
-void upb_status_copy(upb_status *to, const upb_status *from);
 
-UPB_END_EXTERN_C
+UPB_INLINE void upb_status_setoom(upb_status *status) {
+  upb_status_seterrmsg(status, "out of memory");
+}
 
 #ifdef __cplusplus
+}  /* extern "C" */
 
 class upb::Status {
  public:
-  Status() { upb_status_clear(this); }
+  Status() { upb_status_clear(&status_); }
+
+  upb_status* ptr() { return &status_; }
 
   /* Returns true if there is no error. */
-  bool ok() const { return upb_ok(this); }
+  bool ok() const { return upb_ok(&status_); }
 
-  /* Optional error space and code, useful if the caller wants to
-   * programmatically check the specific kind of error. */
-  ErrorSpace* error_space() { return upb_status_errspace(this); }
-  int error_code() const { return upb_status_errcode(this); }
-
-  /* The returned string is invalidated by any other call into the status. */
-  const char *error_message() const { return upb_status_errmsg(this); }
+  /* Guaranteed to be NULL-terminated. */
+  const char *error_message() const { return upb_status_errmsg(&status_); }
 
   /* The error message will be truncated if it is longer than
    * UPB_STATUS_MAX_MESSAGE-4. */
-  void SetErrorMessage(const char* msg) { upb_status_seterrmsg(this, msg); }
-  void SetFormattedErrorMessage(const char* fmt, ...) {
+  void SetErrorMessage(const char *msg) { upb_status_seterrmsg(&status_, msg); }
+  void SetFormattedErrorMessage(const char *fmt, ...) {
     va_list args;
     va_start(args, fmt);
-    upb_status_vseterrf(this, fmt, args);
+    upb_status_vseterrf(&status_, fmt, args);
     va_end(args);
   }
 
   /* Resets the status to a successful state with no message. */
-  void Clear() { upb_status_clear(this); }
-
-  void CopyFrom(const Status& other) { upb_status_copy(this, &other); }
+  void Clear() { upb_status_clear(&status_); }
 
  private:
-  UPB_DISALLOW_COPY_AND_ASSIGN(Status)
-#else
-struct upb_status {
-#endif
-  bool ok_;
-
-  /* Specific status code defined by some error space (optional). */
-  int code_;
-  upb_errorspace *error_space_;
-
-  /* TODO(haberman): add file/line of error? */
-
-  /* Error message; NULL-terminated. */
-  char msg[UPB_STATUS_MAX_MESSAGE];
+  upb_status status_;
 };
 
-#define UPB_STATUS_INIT {true, 0, NULL, {0}}
+#endif  /* __cplusplus */
 
+/** upb_alloc *****************************************************************/
 
-/** Built-in error spaces. ****************************************************/
-
-/* Errors raised by upb that we want to be able to detect programmatically. */
-typedef enum {
-  UPB_NOMEM   /* Can't reuse ENOMEM because it is POSIX, not ISO C. */
-} upb_errcode_t;
-
-extern upb_errorspace upb_upberr;
-
-void upb_upberr_setoom(upb_status *s);
-
-/* Since errno is defined by standard C, we define an error space for it in
- * core upb.  Other error spaces should be defined in other, platform-specific
- * modules. */
-
-extern upb_errorspace upb_errnoerr;
-
-
-/** upb::Allocator ************************************************************/
-
-/* A upb::Allocator is a possibly-stateful allocator object.
+/* A upb_alloc is a possibly-stateful allocator object.
  *
  * It could either be an arena allocator (which doesn't require individual
  * free() calls) or a regular malloc() (which does).  The client must therefore
  * free memory unless it knows that the allocator is an arena allocator. */
-UPB_DECLARE_TYPE(upb::Allocator, upb_alloc)
+
+struct upb_alloc;
+typedef struct upb_alloc upb_alloc;
 
 /* A malloc()/free() function.
  * If "size" is 0 then the function acts like free(), otherwise it acts like
@@ -551,19 +235,7 @@
 typedef void *upb_alloc_func(upb_alloc *alloc, void *ptr, size_t oldsize,
                              size_t size);
 
-#ifdef __cplusplus
-
-class upb::Allocator UPB_FINAL {
- public:
-  Allocator() {}
-
- private:
-  UPB_DISALLOW_COPY_AND_ASSIGN(Allocator)
-
- public:
-#else
 struct upb_alloc {
-#endif  /* __cplusplus */
   upb_alloc_func *func;
 };
 
@@ -604,212 +276,91 @@
   upb_free(&upb_alloc_global, ptr);
 }
 
-/* upb::Arena *****************************************************************/
+/* upb_arena ******************************************************************/
 
-/* upb::Arena is a specific allocator implementation that uses arena allocation.
+/* upb_arena is a specific allocator implementation that uses arena allocation.
  * The user provides an allocator that will be used to allocate the underlying
  * arena blocks.  Arenas by nature do not require the individual allocations
  * to be freed.  However the Arena does allow users to register cleanup
  * functions that will run when the arena is destroyed.
  *
- * A upb::Arena is *not* thread-safe.
+ * A upb_arena is *not* thread-safe.
  *
  * You could write a thread-safe arena allocator that satisfies the
- * upb::Allocator interface, but it would not be as efficient for the
+ * upb_alloc interface, but it would not be as efficient for the
  * single-threaded case. */
-UPB_DECLARE_TYPE(upb::Arena, upb_arena)
 
 typedef void upb_cleanup_func(void *ud);
 
-#define UPB_ARENA_BLOCK_OVERHEAD (sizeof(size_t)*4)
-
-UPB_BEGIN_EXTERN_C
-
-void upb_arena_init(upb_arena *a);
-void upb_arena_init2(upb_arena *a, void *mem, size_t n, upb_alloc *alloc);
-void upb_arena_uninit(upb_arena *a);
-bool upb_arena_addcleanup(upb_arena *a, upb_cleanup_func *func, void *ud);
-size_t upb_arena_bytesallocated(const upb_arena *a);
-void upb_arena_setnextblocksize(upb_arena *a, size_t size);
-void upb_arena_setmaxblocksize(upb_arena *a, size_t size);
-UPB_INLINE upb_alloc *upb_arena_alloc(upb_arena *a) { return (upb_alloc*)a; }
-
-UPB_END_EXTERN_C
+struct upb_arena;
+typedef struct upb_arena upb_arena;
 
 #ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Creates an arena from the given initial block (if any -- n may be 0).
+ * Additional blocks will be allocated from |alloc|.  If |alloc| is NULL, this
+ * is a fixed-size arena and cannot grow. */
+upb_arena *upb_arena_init(void *mem, size_t n, upb_alloc *alloc);
+void upb_arena_free(upb_arena *a);
+bool upb_arena_addcleanup(upb_arena *a, void *ud, upb_cleanup_func *func);
+size_t upb_arena_bytesallocated(const upb_arena *a);
+
+UPB_INLINE upb_alloc *upb_arena_alloc(upb_arena *a) { return (upb_alloc*)a; }
+
+/* Convenience wrappers around upb_alloc functions. */
+
+UPB_INLINE void *upb_arena_malloc(upb_arena *a, size_t size) {
+  return upb_malloc(upb_arena_alloc(a), size);
+}
+
+UPB_INLINE void *upb_arena_realloc(upb_arena *a, void *ptr, size_t oldsize,
+                                   size_t size) {
+  return upb_realloc(upb_arena_alloc(a), ptr, oldsize, size);
+}
+
+UPB_INLINE upb_arena *upb_arena_new() {
+  return upb_arena_init(NULL, 0, &upb_alloc_global);
+}
+
+#ifdef __cplusplus
+}  /* extern "C" */
 
 class upb::Arena {
  public:
   /* A simple arena with no initial memory block and the default allocator. */
-  Arena() { upb_arena_init(this); }
+  Arena() : ptr_(upb_arena_new(), upb_arena_free) {}
 
-  /* Constructs an arena with the given initial block which allocates blocks
-   * with the given allocator.  The given allocator must outlive the Arena.
-   *
-   * If you pass NULL for the allocator it will default to the global allocator
-   * upb_alloc_global, and NULL/0 for the initial block will cause there to be
-   * no initial block. */
-  Arena(void *mem, size_t len, Allocator* a) {
-    upb_arena_init2(this, mem, len, a);
-  }
-
-  ~Arena() { upb_arena_uninit(this); }
-
-  /* Sets the size of the next block the Arena will request (unless the
-   * requested allocation is larger).  Each block will double in size until the
-   * max limit is reached. */
-  void SetNextBlockSize(size_t size) { upb_arena_setnextblocksize(this, size); }
-
-  /* Sets the maximum block size.  No blocks larger than this will be requested
-   * from the underlying allocator unless individual arena allocations are
-   * larger. */
-  void SetMaxBlockSize(size_t size) { upb_arena_setmaxblocksize(this, size); }
+  upb_arena* ptr() { return ptr_.get(); }
 
   /* Allows this arena to be used as a generic allocator.
    *
    * The arena does not need free() calls so when using Arena as an allocator
    * it is safe to skip them.  However they are no-ops so there is no harm in
    * calling free() either. */
-  Allocator* allocator() { return upb_arena_alloc(this); }
+  upb_alloc *allocator() { return upb_arena_alloc(ptr_.get()); }
 
   /* Add a cleanup function to run when the arena is destroyed.
    * Returns false on out-of-memory. */
-  bool AddCleanup(upb_cleanup_func* func, void* ud) {
-    return upb_arena_addcleanup(this, func, ud);
+  bool AddCleanup(void *ud, upb_cleanup_func* func) {
+    return upb_arena_addcleanup(ptr_.get(), ud, func);
   }
 
   /* Total number of bytes that have been allocated.  It is undefined what
-   * Realloc() does to this counter. */
-  size_t BytesAllocated() const {
-    return upb_arena_bytesallocated(this);
-  }
+   * Realloc() does to &arena_ counter. */
+  size_t BytesAllocated() const { return upb_arena_bytesallocated(ptr_.get()); }
 
  private:
-  UPB_DISALLOW_COPY_AND_ASSIGN(Arena)
-
-#else
-struct upb_arena {
-#endif  /* __cplusplus */
-  /* We implement the allocator interface.
-   * This must be the first member of upb_arena! */
-  upb_alloc alloc;
-
-  /* Allocator to allocate arena blocks.  We are responsible for freeing these
-   * when we are destroyed. */
-  upb_alloc *block_alloc;
-
-  size_t bytes_allocated;
-  size_t next_block_size;
-  size_t max_block_size;
-
-  /* Linked list of blocks.  Points to an arena_block, defined in env.c */
-  void *block_head;
-
-  /* Cleanup entries.  Pointer to a cleanup_ent, defined in env.c */
-  void *cleanup_head;
-
-  /* For future expansion, since the size of this struct is exposed to users. */
-  void *future1;
-  void *future2;
+  std::unique_ptr<upb_arena, decltype(&upb_arena_free)> ptr_;
 };
 
-
-/* upb::Environment ***********************************************************/
-
-/* A upb::Environment provides a means for injecting malloc and an
- * error-reporting callback into encoders/decoders.  This allows them to be
- * independent of nearly all assumptions about their actual environment.
- *
- * It is also a container for allocating the encoders/decoders themselves that
- * insulates clients from knowing their actual size.  This provides ABI
- * compatibility even if the size of the objects change.  And this allows the
- * structure definitions to be in the .c files instead of the .h files, making
- * the .h files smaller and more readable.
- *
- * We might want to consider renaming this to "Pipeline" if/when the concept of
- * a pipeline element becomes more formalized. */
-UPB_DECLARE_TYPE(upb::Environment, upb_env)
-
-/* A function that receives an error report from an encoder or decoder.  The
- * callback can return true to request that the error should be recovered, but
- * if the error is not recoverable this has no effect. */
-typedef bool upb_error_func(void *ud, const upb_status *status);
-
-UPB_BEGIN_EXTERN_C
-
-void upb_env_init(upb_env *e);
-void upb_env_init2(upb_env *e, void *mem, size_t n, upb_alloc *alloc);
-void upb_env_uninit(upb_env *e);
-
-void upb_env_initonly(upb_env *e);
-
-UPB_INLINE upb_arena *upb_env_arena(upb_env *e) { return (upb_arena*)e; }
-bool upb_env_ok(const upb_env *e);
-void upb_env_seterrorfunc(upb_env *e, upb_error_func *func, void *ud);
-
-/* Convenience wrappers around the methods of the contained arena. */
-void upb_env_reporterrorsto(upb_env *e, upb_status *s);
-bool upb_env_reporterror(upb_env *e, const upb_status *s);
-void *upb_env_malloc(upb_env *e, size_t size);
-void *upb_env_realloc(upb_env *e, void *ptr, size_t oldsize, size_t size);
-void upb_env_free(upb_env *e, void *ptr);
-bool upb_env_addcleanup(upb_env *e, upb_cleanup_func *func, void *ud);
-size_t upb_env_bytesallocated(const upb_env *e);
-
-UPB_END_EXTERN_C
-
-#ifdef __cplusplus
-
-class upb::Environment {
- public:
-  /* The given Arena must outlive this environment. */
-  Environment() { upb_env_initonly(this); }
-
-  Environment(void *mem, size_t len, Allocator *a) : arena_(mem, len, a) {
-    upb_env_initonly(this);
-  }
-
-  Arena* arena() { return upb_env_arena(this); }
-
-  /* Set a custom error reporting function. */
-  void SetErrorFunction(upb_error_func* func, void* ud) {
-    upb_env_seterrorfunc(this, func, ud);
-  }
-
-  /* Set the error reporting function to simply copy the status to the given
-   * status and abort. */
-  void ReportErrorsTo(Status* status) { upb_env_reporterrorsto(this, status); }
-
-  /* Returns true if all allocations and AddCleanup() calls have succeeded,
-   * and no errors were reported with ReportError() (except ones that recovered
-   * successfully). */
-  bool ok() const { return upb_env_ok(this); }
-
-  /* Reports an error to this environment's callback, returning true if
-   * the caller should try to recover. */
-  bool ReportError(const Status* status) {
-    return upb_env_reporterror(this, status);
-  }
-
- private:
-  UPB_DISALLOW_COPY_AND_ASSIGN(Environment)
-
-#else
-struct upb_env {
-#endif  /* __cplusplus */
-  upb_arena arena_;
-  upb_error_func *error_func_;
-  void *error_ud_;
-  bool ok_;
-};
-
+#endif
 
 /* upb::InlinedArena **********************************************************/
-/* upb::InlinedEnvironment ****************************************************/
 
-/* upb::InlinedArena and upb::InlinedEnvironment seed their arenas with a
- * predefined amount of memory.  No heap memory will be allocated until the
- * initial block is exceeded.
+/* upb::InlinedArena seeds the arenas with a predefined amount of memory.  No
+ * heap memory will be allocated until the initial block is exceeded.
  *
  * These types only exist in C++ */
 
@@ -817,32 +368,2230 @@
 
 template <int N> class upb::InlinedArena : public upb::Arena {
  public:
-  InlinedArena() : Arena(initial_block_, N, NULL) {}
-  explicit InlinedArena(Allocator* a) : Arena(initial_block_, N, a) {}
+  InlinedArena() : ptr_(upb_arena_new(&initial_block_, N, &upb_alloc_global)) {}
+
+  upb_arena* ptr() { return ptr_.get(); }
 
  private:
-  UPB_DISALLOW_COPY_AND_ASSIGN(InlinedArena)
+  InlinedArena(const InlinedArena*) = delete;
+  InlinedArena& operator=(const InlinedArena*) = delete;
 
-  char initial_block_[N + UPB_ARENA_BLOCK_OVERHEAD];
-};
-
-template <int N> class upb::InlinedEnvironment : public upb::Environment {
- public:
-  InlinedEnvironment() : Environment(initial_block_, N, NULL) {}
-  explicit InlinedEnvironment(Allocator *a)
-      : Environment(initial_block_, N, a) {}
-
- private:
-  UPB_DISALLOW_COPY_AND_ASSIGN(InlinedEnvironment)
-
-  char initial_block_[N + UPB_ARENA_BLOCK_OVERHEAD];
+  std::unique_ptr<upb_arena, decltype(&upb_arena_free)> ptr_;
+  char initial_block_[N];
 };
 
 #endif  /* __cplusplus */
 
+/* Constants ******************************************************************/
 
+/* Generic function type. */
+typedef void upb_func();
+
+/* A list of types as they are encoded on-the-wire. */
+typedef enum {
+  UPB_WIRE_TYPE_VARINT      = 0,
+  UPB_WIRE_TYPE_64BIT       = 1,
+  UPB_WIRE_TYPE_DELIMITED   = 2,
+  UPB_WIRE_TYPE_START_GROUP = 3,
+  UPB_WIRE_TYPE_END_GROUP   = 4,
+  UPB_WIRE_TYPE_32BIT       = 5
+} upb_wiretype_t;
+
+/* The types a field can have.  Note that this list is not identical to the
+ * types defined in descriptor.proto, which gives INT32 and SINT32 separate
+ * types (we distinguish the two with the "integer encoding" enum below). */
+typedef enum {
+  /* Types stored in 1 byte. */
+  UPB_TYPE_BOOL     = 1,
+  /* Types stored in 4 bytes. */
+  UPB_TYPE_FLOAT    = 2,
+  UPB_TYPE_INT32    = 3,
+  UPB_TYPE_UINT32   = 4,
+  UPB_TYPE_ENUM     = 5,  /* Enum values are int32. */
+  /* Types stored as pointers (probably 4 or 8 bytes). */
+  UPB_TYPE_STRING   = 6,
+  UPB_TYPE_BYTES    = 7,
+  UPB_TYPE_MESSAGE  = 8,
+  /* Types stored as 8 bytes. */
+  UPB_TYPE_DOUBLE   = 9,
+  UPB_TYPE_INT64    = 10,
+  UPB_TYPE_UINT64   = 11
+} upb_fieldtype_t;
+
+/* The repeated-ness of each field; this matches descriptor.proto. */
+typedef enum {
+  UPB_LABEL_OPTIONAL = 1,
+  UPB_LABEL_REQUIRED = 2,
+  UPB_LABEL_REPEATED = 3
+} upb_label_t;
+
+/* Descriptor types, as defined in descriptor.proto. */
+typedef enum {
+  UPB_DESCRIPTOR_TYPE_DOUBLE   = 1,
+  UPB_DESCRIPTOR_TYPE_FLOAT    = 2,
+  UPB_DESCRIPTOR_TYPE_INT64    = 3,
+  UPB_DESCRIPTOR_TYPE_UINT64   = 4,
+  UPB_DESCRIPTOR_TYPE_INT32    = 5,
+  UPB_DESCRIPTOR_TYPE_FIXED64  = 6,
+  UPB_DESCRIPTOR_TYPE_FIXED32  = 7,
+  UPB_DESCRIPTOR_TYPE_BOOL     = 8,
+  UPB_DESCRIPTOR_TYPE_STRING   = 9,
+  UPB_DESCRIPTOR_TYPE_GROUP    = 10,
+  UPB_DESCRIPTOR_TYPE_MESSAGE  = 11,
+  UPB_DESCRIPTOR_TYPE_BYTES    = 12,
+  UPB_DESCRIPTOR_TYPE_UINT32   = 13,
+  UPB_DESCRIPTOR_TYPE_ENUM     = 14,
+  UPB_DESCRIPTOR_TYPE_SFIXED32 = 15,
+  UPB_DESCRIPTOR_TYPE_SFIXED64 = 16,
+  UPB_DESCRIPTOR_TYPE_SINT32   = 17,
+  UPB_DESCRIPTOR_TYPE_SINT64   = 18
+} upb_descriptortype_t;
+
+extern const uint8_t upb_desctype_to_fieldtype[];
 
 #endif  /* UPB_H_ */
+/*
+** structs.int.h: structures definitions that are internal to upb.
+*/
+
+#ifndef UPB_STRUCTS_H_
+#define UPB_STRUCTS_H_
+
+
+struct upb_array {
+  upb_fieldtype_t type;
+  uint8_t element_size;
+  void *data;   /* Each element is element_size. */
+  size_t len;   /* Measured in elements. */
+  size_t size;  /* Measured in elements. */
+  upb_arena *arena;
+};
+
+#endif  /* UPB_STRUCTS_H_ */
+
+
+#ifdef __cplusplus
+
+namespace upb {
+class Array;
+class Map;
+class MapIterator;
+class MessageLayout;
+}
+
+#endif
+
+/* TODO(haberman): C++ accessors */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef void upb_msg;
+
+struct upb_array;
+typedef struct upb_array upb_array;
+
+struct upb_map;
+typedef struct upb_map upb_map;
+
+struct upb_mapiter;
+typedef struct upb_mapiter upb_mapiter;
+
+/** upb_msglayout *************************************************************/
+
+/* upb_msglayout represents the memory layout of a given upb_msgdef.  The
+ * members are public so generated code can initialize them, but users MUST NOT
+ * read or write any of its members. */
+
+typedef struct {
+  uint32_t number;
+  uint16_t offset;
+  int16_t presence;      /* If >0, hasbit_index+1.  If <0, oneof_index+1. */
+  uint16_t submsg_index;  /* undefined if descriptortype != MESSAGE or GROUP. */
+  uint8_t descriptortype;
+  uint8_t label;
+} upb_msglayout_field;
+
+typedef struct upb_msglayout {
+  const struct upb_msglayout *const* submsgs;
+  const upb_msglayout_field *fields;
+  /* Must be aligned to sizeof(void*).  Doesn't include internal members like
+   * unknown fields, extension dict, pointer to msglayout, etc. */
+  uint16_t size;
+  uint16_t field_count;
+  bool extendable;
+} upb_msglayout;
+
+/** upb_strview ************************************************************/
+
+typedef struct {
+  const char *data;
+  size_t size;
+} upb_strview;
+
+UPB_INLINE upb_strview upb_strview_make(const char *data, size_t size) {
+  upb_strview ret;
+  ret.data = data;
+  ret.size = size;
+  return ret;
+}
+
+UPB_INLINE upb_strview upb_strview_makez(const char *data) {
+  return upb_strview_make(data, strlen(data));
+}
+
+UPB_INLINE bool upb_strview_eql(upb_strview a, upb_strview b) {
+  return a.size == b.size && memcmp(a.data, b.data, a.size) == 0;
+}
+
+#define UPB_STRVIEW_INIT(ptr, len) {ptr, len}
+
+#define UPB_STRVIEW_FORMAT "%.*s"
+#define UPB_STRVIEW_ARGS(view) (int)(view).size, (view).data
+
+/** upb_msgval ****************************************************************/
+
+/* A union representing all possible protobuf values.  Used for generic get/set
+ * operations. */
+
+typedef union {
+  bool b;
+  float flt;
+  double dbl;
+  int32_t i32;
+  int64_t i64;
+  uint32_t u32;
+  uint64_t u64;
+  const upb_map* map;
+  const upb_msg* msg;
+  const upb_array* arr;
+  const void* ptr;
+  upb_strview str;
+} upb_msgval;
+
+#define ACCESSORS(name, membername, ctype) \
+  UPB_INLINE ctype upb_msgval_get ## name(upb_msgval v) { \
+    return v.membername; \
+  } \
+  UPB_INLINE void upb_msgval_set ## name(upb_msgval *v, ctype cval) { \
+    v->membername = cval; \
+  } \
+  UPB_INLINE upb_msgval upb_msgval_ ## name(ctype v) { \
+    upb_msgval ret; \
+    ret.membername = v; \
+    return ret; \
+  }
+
+ACCESSORS(bool,   b,   bool)
+ACCESSORS(float,  flt, float)
+ACCESSORS(double, dbl, double)
+ACCESSORS(int32,  i32, int32_t)
+ACCESSORS(int64,  i64, int64_t)
+ACCESSORS(uint32, u32, uint32_t)
+ACCESSORS(uint64, u64, uint64_t)
+ACCESSORS(map,    map, const upb_map*)
+ACCESSORS(msg,    msg, const upb_msg*)
+ACCESSORS(ptr,    ptr, const void*)
+ACCESSORS(arr,    arr, const upb_array*)
+ACCESSORS(str,    str, upb_strview)
+
+#undef ACCESSORS
+
+UPB_INLINE upb_msgval upb_msgval_makestr(const char *data, size_t size) {
+  return upb_msgval_str(upb_strview_make(data, size));
+}
+
+/** upb_msg *******************************************************************/
+
+/* A upb_msg represents a protobuf message.  It always corresponds to a specific
+ * upb_msglayout, which describes how it is laid out in memory.  */
+
+/* Creates a new message of the given type/layout in this arena. */
+upb_msg *upb_msg_new(const upb_msglayout *l, upb_arena *a);
+
+/* Returns the arena for the given message. */
+upb_arena *upb_msg_arena(const upb_msg *msg);
+
+void upb_msg_addunknown(upb_msg *msg, const char *data, size_t len);
+const char *upb_msg_getunknown(const upb_msg *msg, size_t *len);
+
+/* Read-only message API.  Can be safely called by anyone. */
+
+/* Returns the value associated with this field:
+ *   - for scalar fields (including strings), the value directly.
+ *   - return upb_msg*, or upb_map* for msg/map.
+ *     If the field is unset for these field types, returns NULL.
+ *
+ * TODO(haberman): should we let users store cached array/map/msg
+ * pointers here for fields that are unset?  Could be useful for the
+ * strongly-owned submessage model (ie. generated C API that doesn't use
+ * arenas).
+ */
+upb_msgval upb_msg_get(const upb_msg *msg,
+                       int field_index,
+                       const upb_msglayout *l);
+
+/* May only be called for fields where upb_fielddef_haspresence(f) == true. */
+bool upb_msg_has(const upb_msg *msg,
+                 int field_index,
+                 const upb_msglayout *l);
+
+/* Mutable message API.  May only be called by the owner of the message who
+ * knows its ownership scheme and how to keep it consistent. */
+
+/* Sets the given field to the given value.  Does not perform any memory
+ * management: if you overwrite a pointer to a msg/array/map/string without
+ * cleaning it up (or using an arena) it will leak.
+ */
+void upb_msg_set(upb_msg *msg,
+                 int field_index,
+                 upb_msgval val,
+                 const upb_msglayout *l);
+
+/* For a primitive field, set it back to its default. For repeated, string, and
+ * submessage fields set it back to NULL.  This could involve releasing some
+ * internal memory (for example, from an extension dictionary), but it is not
+ * recursive in any way and will not recover any memory that may be used by
+ * arrays/maps/strings/msgs that this field may have pointed to.
+ */
+bool upb_msg_clearfield(upb_msg *msg,
+                        int field_index,
+                        const upb_msglayout *l);
+
+/* TODO(haberman): copyfrom()/mergefrom()? */
+
+/** upb_array *****************************************************************/
+
+/* A upb_array stores data for a repeated field.  The memory management
+ * semantics are the same as upb_msg.  A upb_array allocates dynamic
+ * memory internally for the array elements. */
+
+upb_array *upb_array_new(upb_fieldtype_t type, upb_arena *a);
+upb_fieldtype_t upb_array_type(const upb_array *arr);
+
+/* Read-only interface.  Safe for anyone to call. */
+
+size_t upb_array_size(const upb_array *arr);
+upb_msgval upb_array_get(const upb_array *arr, size_t i);
+
+/* Write interface.  May only be called by the message's owner who can enforce
+ * its memory management invariants. */
+
+bool upb_array_set(upb_array *arr, size_t i, upb_msgval val);
+
+/** upb_map *******************************************************************/
+
+/* A upb_map stores data for a map field.  The memory management semantics are
+ * the same as upb_msg, with one notable exception.  upb_map will internally
+ * store a copy of all string keys, but *not* any string values or submessages.
+ * So you must ensure that any string or message values outlive the map, and you
+ * must delete them manually when they are no longer required. */
+
+upb_map *upb_map_new(upb_fieldtype_t ktype, upb_fieldtype_t vtype,
+                     upb_arena *a);
+
+/* Read-only interface.  Safe for anyone to call. */
+
+size_t upb_map_size(const upb_map *map);
+upb_fieldtype_t upb_map_keytype(const upb_map *map);
+upb_fieldtype_t upb_map_valuetype(const upb_map *map);
+bool upb_map_get(const upb_map *map, upb_msgval key, upb_msgval *val);
+
+/* Write interface.  May only be called by the message's owner who can enforce
+ * its memory management invariants. */
+
+/* Sets or overwrites an entry in the map.  Return value indicates whether
+ * the operation succeeded or failed with OOM, and also whether an existing
+ * key was replaced or not. */
+bool upb_map_set(upb_map *map,
+                 upb_msgval key, upb_msgval val,
+                 upb_msgval *valremoved);
+
+/* Deletes an entry in the map.  Returns true if the key was present. */
+bool upb_map_del(upb_map *map, upb_msgval key);
+
+/** upb_mapiter ***************************************************************/
+
+/* For iterating over a map.  Map iterators are invalidated by mutations to the
+ * map, but an invalidated iterator will never return junk or crash the process.
+ * An invalidated iterator may return entries that were already returned though,
+ * and if you keep invalidating the iterator during iteration, the program may
+ * enter an infinite loop. */
+
+size_t upb_mapiter_sizeof();
+
+void upb_mapiter_begin(upb_mapiter *i, const upb_map *t);
+upb_mapiter *upb_mapiter_new(const upb_map *t, upb_alloc *a);
+void upb_mapiter_free(upb_mapiter *i, upb_alloc *a);
+void upb_mapiter_next(upb_mapiter *i);
+bool upb_mapiter_done(const upb_mapiter *i);
+
+upb_msgval upb_mapiter_key(const upb_mapiter *i);
+upb_msgval upb_mapiter_value(const upb_mapiter *i);
+void upb_mapiter_setdone(upb_mapiter *i);
+bool upb_mapiter_isequal(const upb_mapiter *i1, const upb_mapiter *i2);
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif /* UPB_MSG_H_ */
+/* This file was generated by upbc (the upb compiler) from the input
+ * file:
+ *
+ *     google/protobuf/descriptor.proto
+ *
+ * Do not edit -- your changes will be discarded when the file is
+ * regenerated. */
+
+#ifndef GOOGLE_PROTOBUF_DESCRIPTOR_PROTO_UPB_H_
+#define GOOGLE_PROTOBUF_DESCRIPTOR_PROTO_UPB_H_
+
+/*
+** Functions for use by generated code.  These are not public and users must
+** not call them directly.
+*/
+
+#ifndef UPB_GENERATED_UTIL_H_
+#define UPB_GENERATED_UTIL_H_
+
+#include <stdint.h>
+
+#define PTR_AT(msg, ofs, type) (type*)((const char*)msg + ofs)
+
+UPB_INLINE const void *_upb_array_accessor(const void *msg, size_t ofs,
+                                           size_t *size) {
+  const upb_array *arr = *PTR_AT(msg, ofs, const upb_array*);
+  if (arr) {
+    if (size) *size = arr->len;
+    return arr->data;
+  } else {
+    if (size) *size = 0;
+    return NULL;
+  }
+}
+
+UPB_INLINE void *_upb_array_mutable_accessor(void *msg, size_t ofs,
+                                             size_t *size) {
+  upb_array *arr = *PTR_AT(msg, ofs, upb_array*);
+  if (arr) {
+    if (size) *size = arr->len;
+    return arr->data;
+  } else {
+    if (size) *size = 0;
+    return NULL;
+  }
+}
+
+/* TODO(haberman): this is a mess.  It will improve when upb_array no longer
+ * carries reflective state (type, elem_size). */
+UPB_INLINE void *_upb_array_resize_accessor(void *msg, size_t ofs, size_t size,
+                                            size_t elem_size,
+                                            upb_fieldtype_t type,
+                                            upb_arena *arena) {
+  upb_array *arr = *PTR_AT(msg, ofs, upb_array*);
+
+  if (!arr) {
+    arr = upb_array_new(type, arena);
+    if (!arr) return NULL;
+    *PTR_AT(msg, ofs, upb_array*) = arr;
+  }
+
+  if (size > arr->size) {
+    size_t new_size = UPB_MAX(arr->size, 4);
+    size_t old_bytes = arr->size * elem_size;
+    size_t new_bytes;
+    while (new_size < size) new_size *= 2;
+    new_bytes = new_size * elem_size;
+    arr->data = upb_arena_realloc(arena, arr->data, old_bytes, new_bytes);
+    if (!arr->data) {
+      return NULL;
+    }
+    arr->size = new_size;
+  }
+
+  arr->len = size;
+  return arr->data;
+}
+
+UPB_INLINE bool _upb_array_append_accessor(void *msg, size_t ofs,
+                                           size_t elem_size,
+                                           upb_fieldtype_t type,
+                                           const void *value,
+                                           upb_arena *arena) {
+  upb_array *arr = *PTR_AT(msg, ofs, upb_array*);
+  size_t i = arr ? arr->len : 0;
+  void *data =
+      _upb_array_resize_accessor(msg, ofs, i + 1, elem_size, type, arena);
+  if (!data) return false;
+  memcpy(PTR_AT(data, i * elem_size, char), value, elem_size);
+  return true;
+}
+
+UPB_INLINE bool _upb_has_field(const void *msg, size_t idx) {
+  return (*PTR_AT(msg, idx / 8, const char) & (1 << (idx % 8))) != 0;
+}
+
+UPB_INLINE bool _upb_sethas(const void *msg, size_t idx) {
+  return (*PTR_AT(msg, idx / 8, char)) |= (1 << (idx % 8));
+}
+
+UPB_INLINE bool _upb_clearhas(const void *msg, size_t idx) {
+  return (*PTR_AT(msg, idx / 8, char)) &= ~(1 << (idx % 8));
+}
+
+UPB_INLINE bool _upb_has_oneof_field(const void *msg, size_t case_ofs, int32_t num) {
+  return *PTR_AT(msg, case_ofs, int32_t) == num;
+}
+
+#undef PTR_AT
+
+#endif  /* UPB_GENERATED_UTIL_H_ */
+
+
+/*
+** upb_decode: parsing into a upb_msg using a upb_msglayout.
+*/
+
+#ifndef UPB_DECODE_H_
+#define UPB_DECODE_H_
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+bool upb_decode(upb_strview buf, upb_msg *msg, const upb_msglayout *l);
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif  /* UPB_DECODE_H_ */
+/*
+** upb_encode: parsing into a upb_msg using a upb_msglayout.
+*/
+
+#ifndef UPB_ENCODE_H_
+#define UPB_ENCODE_H_
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+char *upb_encode(const void *msg, const upb_msglayout *l, upb_arena *arena,
+                 size_t *size);
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif  /* UPB_ENCODE_H_ */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct google_protobuf_FileDescriptorSet;
+struct google_protobuf_FileDescriptorProto;
+struct google_protobuf_DescriptorProto;
+struct google_protobuf_DescriptorProto_ExtensionRange;
+struct google_protobuf_DescriptorProto_ReservedRange;
+struct google_protobuf_ExtensionRangeOptions;
+struct google_protobuf_FieldDescriptorProto;
+struct google_protobuf_OneofDescriptorProto;
+struct google_protobuf_EnumDescriptorProto;
+struct google_protobuf_EnumDescriptorProto_EnumReservedRange;
+struct google_protobuf_EnumValueDescriptorProto;
+struct google_protobuf_ServiceDescriptorProto;
+struct google_protobuf_MethodDescriptorProto;
+struct google_protobuf_FileOptions;
+struct google_protobuf_MessageOptions;
+struct google_protobuf_FieldOptions;
+struct google_protobuf_OneofOptions;
+struct google_protobuf_EnumOptions;
+struct google_protobuf_EnumValueOptions;
+struct google_protobuf_ServiceOptions;
+struct google_protobuf_MethodOptions;
+struct google_protobuf_UninterpretedOption;
+struct google_protobuf_UninterpretedOption_NamePart;
+struct google_protobuf_SourceCodeInfo;
+struct google_protobuf_SourceCodeInfo_Location;
+struct google_protobuf_GeneratedCodeInfo;
+struct google_protobuf_GeneratedCodeInfo_Annotation;
+typedef struct google_protobuf_FileDescriptorSet google_protobuf_FileDescriptorSet;
+typedef struct google_protobuf_FileDescriptorProto google_protobuf_FileDescriptorProto;
+typedef struct google_protobuf_DescriptorProto google_protobuf_DescriptorProto;
+typedef struct google_protobuf_DescriptorProto_ExtensionRange google_protobuf_DescriptorProto_ExtensionRange;
+typedef struct google_protobuf_DescriptorProto_ReservedRange google_protobuf_DescriptorProto_ReservedRange;
+typedef struct google_protobuf_ExtensionRangeOptions google_protobuf_ExtensionRangeOptions;
+typedef struct google_protobuf_FieldDescriptorProto google_protobuf_FieldDescriptorProto;
+typedef struct google_protobuf_OneofDescriptorProto google_protobuf_OneofDescriptorProto;
+typedef struct google_protobuf_EnumDescriptorProto google_protobuf_EnumDescriptorProto;
+typedef struct google_protobuf_EnumDescriptorProto_EnumReservedRange google_protobuf_EnumDescriptorProto_EnumReservedRange;
+typedef struct google_protobuf_EnumValueDescriptorProto google_protobuf_EnumValueDescriptorProto;
+typedef struct google_protobuf_ServiceDescriptorProto google_protobuf_ServiceDescriptorProto;
+typedef struct google_protobuf_MethodDescriptorProto google_protobuf_MethodDescriptorProto;
+typedef struct google_protobuf_FileOptions google_protobuf_FileOptions;
+typedef struct google_protobuf_MessageOptions google_protobuf_MessageOptions;
+typedef struct google_protobuf_FieldOptions google_protobuf_FieldOptions;
+typedef struct google_protobuf_OneofOptions google_protobuf_OneofOptions;
+typedef struct google_protobuf_EnumOptions google_protobuf_EnumOptions;
+typedef struct google_protobuf_EnumValueOptions google_protobuf_EnumValueOptions;
+typedef struct google_protobuf_ServiceOptions google_protobuf_ServiceOptions;
+typedef struct google_protobuf_MethodOptions google_protobuf_MethodOptions;
+typedef struct google_protobuf_UninterpretedOption google_protobuf_UninterpretedOption;
+typedef struct google_protobuf_UninterpretedOption_NamePart google_protobuf_UninterpretedOption_NamePart;
+typedef struct google_protobuf_SourceCodeInfo google_protobuf_SourceCodeInfo;
+typedef struct google_protobuf_SourceCodeInfo_Location google_protobuf_SourceCodeInfo_Location;
+typedef struct google_protobuf_GeneratedCodeInfo google_protobuf_GeneratedCodeInfo;
+typedef struct google_protobuf_GeneratedCodeInfo_Annotation google_protobuf_GeneratedCodeInfo_Annotation;
+extern const upb_msglayout google_protobuf_FileDescriptorSet_msginit;
+extern const upb_msglayout google_protobuf_FileDescriptorProto_msginit;
+extern const upb_msglayout google_protobuf_DescriptorProto_msginit;
+extern const upb_msglayout google_protobuf_DescriptorProto_ExtensionRange_msginit;
+extern const upb_msglayout google_protobuf_DescriptorProto_ReservedRange_msginit;
+extern const upb_msglayout google_protobuf_ExtensionRangeOptions_msginit;
+extern const upb_msglayout google_protobuf_FieldDescriptorProto_msginit;
+extern const upb_msglayout google_protobuf_OneofDescriptorProto_msginit;
+extern const upb_msglayout google_protobuf_EnumDescriptorProto_msginit;
+extern const upb_msglayout google_protobuf_EnumDescriptorProto_EnumReservedRange_msginit;
+extern const upb_msglayout google_protobuf_EnumValueDescriptorProto_msginit;
+extern const upb_msglayout google_protobuf_ServiceDescriptorProto_msginit;
+extern const upb_msglayout google_protobuf_MethodDescriptorProto_msginit;
+extern const upb_msglayout google_protobuf_FileOptions_msginit;
+extern const upb_msglayout google_protobuf_MessageOptions_msginit;
+extern const upb_msglayout google_protobuf_FieldOptions_msginit;
+extern const upb_msglayout google_protobuf_OneofOptions_msginit;
+extern const upb_msglayout google_protobuf_EnumOptions_msginit;
+extern const upb_msglayout google_protobuf_EnumValueOptions_msginit;
+extern const upb_msglayout google_protobuf_ServiceOptions_msginit;
+extern const upb_msglayout google_protobuf_MethodOptions_msginit;
+extern const upb_msglayout google_protobuf_UninterpretedOption_msginit;
+extern const upb_msglayout google_protobuf_UninterpretedOption_NamePart_msginit;
+extern const upb_msglayout google_protobuf_SourceCodeInfo_msginit;
+extern const upb_msglayout google_protobuf_SourceCodeInfo_Location_msginit;
+extern const upb_msglayout google_protobuf_GeneratedCodeInfo_msginit;
+extern const upb_msglayout google_protobuf_GeneratedCodeInfo_Annotation_msginit;
+
+/* Enums */
+
+typedef enum {
+  google_protobuf_FieldDescriptorProto_LABEL_OPTIONAL = 1,
+  google_protobuf_FieldDescriptorProto_LABEL_REQUIRED = 2,
+  google_protobuf_FieldDescriptorProto_LABEL_REPEATED = 3
+} google_protobuf_FieldDescriptorProto_Label;
+
+typedef enum {
+  google_protobuf_FieldDescriptorProto_TYPE_DOUBLE = 1,
+  google_protobuf_FieldDescriptorProto_TYPE_FLOAT = 2,
+  google_protobuf_FieldDescriptorProto_TYPE_INT64 = 3,
+  google_protobuf_FieldDescriptorProto_TYPE_UINT64 = 4,
+  google_protobuf_FieldDescriptorProto_TYPE_INT32 = 5,
+  google_protobuf_FieldDescriptorProto_TYPE_FIXED64 = 6,
+  google_protobuf_FieldDescriptorProto_TYPE_FIXED32 = 7,
+  google_protobuf_FieldDescriptorProto_TYPE_BOOL = 8,
+  google_protobuf_FieldDescriptorProto_TYPE_STRING = 9,
+  google_protobuf_FieldDescriptorProto_TYPE_GROUP = 10,
+  google_protobuf_FieldDescriptorProto_TYPE_MESSAGE = 11,
+  google_protobuf_FieldDescriptorProto_TYPE_BYTES = 12,
+  google_protobuf_FieldDescriptorProto_TYPE_UINT32 = 13,
+  google_protobuf_FieldDescriptorProto_TYPE_ENUM = 14,
+  google_protobuf_FieldDescriptorProto_TYPE_SFIXED32 = 15,
+  google_protobuf_FieldDescriptorProto_TYPE_SFIXED64 = 16,
+  google_protobuf_FieldDescriptorProto_TYPE_SINT32 = 17,
+  google_protobuf_FieldDescriptorProto_TYPE_SINT64 = 18
+} google_protobuf_FieldDescriptorProto_Type;
+
+typedef enum {
+  google_protobuf_FieldOptions_STRING = 0,
+  google_protobuf_FieldOptions_CORD = 1,
+  google_protobuf_FieldOptions_STRING_PIECE = 2
+} google_protobuf_FieldOptions_CType;
+
+typedef enum {
+  google_protobuf_FieldOptions_JS_NORMAL = 0,
+  google_protobuf_FieldOptions_JS_STRING = 1,
+  google_protobuf_FieldOptions_JS_NUMBER = 2
+} google_protobuf_FieldOptions_JSType;
+
+typedef enum {
+  google_protobuf_FileOptions_SPEED = 1,
+  google_protobuf_FileOptions_CODE_SIZE = 2,
+  google_protobuf_FileOptions_LITE_RUNTIME = 3
+} google_protobuf_FileOptions_OptimizeMode;
+
+typedef enum {
+  google_protobuf_MethodOptions_IDEMPOTENCY_UNKNOWN = 0,
+  google_protobuf_MethodOptions_NO_SIDE_EFFECTS = 1,
+  google_protobuf_MethodOptions_IDEMPOTENT = 2
+} google_protobuf_MethodOptions_IdempotencyLevel;
+
+/* google.protobuf.FileDescriptorSet */
+
+UPB_INLINE google_protobuf_FileDescriptorSet *google_protobuf_FileDescriptorSet_new(upb_arena *arena) {
+  return (google_protobuf_FileDescriptorSet *)upb_msg_new(&google_protobuf_FileDescriptorSet_msginit, arena);
+}
+UPB_INLINE google_protobuf_FileDescriptorSet *google_protobuf_FileDescriptorSet_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_FileDescriptorSet *ret = google_protobuf_FileDescriptorSet_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_FileDescriptorSet_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_FileDescriptorSet_serialize(const google_protobuf_FileDescriptorSet *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_FileDescriptorSet_msginit, arena, len);
+}
+
+UPB_INLINE const google_protobuf_FileDescriptorProto* const* google_protobuf_FileDescriptorSet_file(const google_protobuf_FileDescriptorSet *msg, size_t *len) { return (const google_protobuf_FileDescriptorProto* const*)_upb_array_accessor(msg, UPB_SIZE(0, 0), len); }
+
+UPB_INLINE google_protobuf_FileDescriptorProto** google_protobuf_FileDescriptorSet_mutable_file(google_protobuf_FileDescriptorSet *msg, size_t *len) {
+  return (google_protobuf_FileDescriptorProto**)_upb_array_mutable_accessor(msg, UPB_SIZE(0, 0), len);
+}
+UPB_INLINE google_protobuf_FileDescriptorProto** google_protobuf_FileDescriptorSet_resize_file(google_protobuf_FileDescriptorSet *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_FileDescriptorProto**)_upb_array_resize_accessor(msg, UPB_SIZE(0, 0), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_FileDescriptorProto* google_protobuf_FileDescriptorSet_add_file(google_protobuf_FileDescriptorSet *msg, upb_arena *arena) {
+  struct google_protobuf_FileDescriptorProto* sub = (struct google_protobuf_FileDescriptorProto*)upb_msg_new(&google_protobuf_FileDescriptorProto_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(0, 0), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+
+
+/* google.protobuf.FileDescriptorProto */
+
+UPB_INLINE google_protobuf_FileDescriptorProto *google_protobuf_FileDescriptorProto_new(upb_arena *arena) {
+  return (google_protobuf_FileDescriptorProto *)upb_msg_new(&google_protobuf_FileDescriptorProto_msginit, arena);
+}
+UPB_INLINE google_protobuf_FileDescriptorProto *google_protobuf_FileDescriptorProto_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_FileDescriptorProto *ret = google_protobuf_FileDescriptorProto_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_FileDescriptorProto_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_FileDescriptorProto_serialize(const google_protobuf_FileDescriptorProto *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_FileDescriptorProto_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_FileDescriptorProto_has_name(const google_protobuf_FileDescriptorProto *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE upb_strview google_protobuf_FileDescriptorProto_name(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)); }
+UPB_INLINE bool google_protobuf_FileDescriptorProto_has_package(const google_protobuf_FileDescriptorProto *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE upb_strview google_protobuf_FileDescriptorProto_package(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(12, 24)); }
+UPB_INLINE upb_strview const* google_protobuf_FileDescriptorProto_dependency(const google_protobuf_FileDescriptorProto *msg, size_t *len) { return (upb_strview const*)_upb_array_accessor(msg, UPB_SIZE(36, 72), len); }
+UPB_INLINE const google_protobuf_DescriptorProto* const* google_protobuf_FileDescriptorProto_message_type(const google_protobuf_FileDescriptorProto *msg, size_t *len) { return (const google_protobuf_DescriptorProto* const*)_upb_array_accessor(msg, UPB_SIZE(40, 80), len); }
+UPB_INLINE const google_protobuf_EnumDescriptorProto* const* google_protobuf_FileDescriptorProto_enum_type(const google_protobuf_FileDescriptorProto *msg, size_t *len) { return (const google_protobuf_EnumDescriptorProto* const*)_upb_array_accessor(msg, UPB_SIZE(44, 88), len); }
+UPB_INLINE const google_protobuf_ServiceDescriptorProto* const* google_protobuf_FileDescriptorProto_service(const google_protobuf_FileDescriptorProto *msg, size_t *len) { return (const google_protobuf_ServiceDescriptorProto* const*)_upb_array_accessor(msg, UPB_SIZE(48, 96), len); }
+UPB_INLINE const google_protobuf_FieldDescriptorProto* const* google_protobuf_FileDescriptorProto_extension(const google_protobuf_FileDescriptorProto *msg, size_t *len) { return (const google_protobuf_FieldDescriptorProto* const*)_upb_array_accessor(msg, UPB_SIZE(52, 104), len); }
+UPB_INLINE bool google_protobuf_FileDescriptorProto_has_options(const google_protobuf_FileDescriptorProto *msg) { return _upb_has_field(msg, 4); }
+UPB_INLINE const google_protobuf_FileOptions* google_protobuf_FileDescriptorProto_options(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_FileOptions*, UPB_SIZE(28, 56)); }
+UPB_INLINE bool google_protobuf_FileDescriptorProto_has_source_code_info(const google_protobuf_FileDescriptorProto *msg) { return _upb_has_field(msg, 5); }
+UPB_INLINE const google_protobuf_SourceCodeInfo* google_protobuf_FileDescriptorProto_source_code_info(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_SourceCodeInfo*, UPB_SIZE(32, 64)); }
+UPB_INLINE int32_t const* google_protobuf_FileDescriptorProto_public_dependency(const google_protobuf_FileDescriptorProto *msg, size_t *len) { return (int32_t const*)_upb_array_accessor(msg, UPB_SIZE(56, 112), len); }
+UPB_INLINE int32_t const* google_protobuf_FileDescriptorProto_weak_dependency(const google_protobuf_FileDescriptorProto *msg, size_t *len) { return (int32_t const*)_upb_array_accessor(msg, UPB_SIZE(60, 120), len); }
+UPB_INLINE bool google_protobuf_FileDescriptorProto_has_syntax(const google_protobuf_FileDescriptorProto *msg) { return _upb_has_field(msg, 3); }
+UPB_INLINE upb_strview google_protobuf_FileDescriptorProto_syntax(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(20, 40)); }
+
+UPB_INLINE void google_protobuf_FileDescriptorProto_set_name(google_protobuf_FileDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)) = value;
+}
+UPB_INLINE void google_protobuf_FileDescriptorProto_set_package(google_protobuf_FileDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(12, 24)) = value;
+}
+UPB_INLINE upb_strview* google_protobuf_FileDescriptorProto_mutable_dependency(google_protobuf_FileDescriptorProto *msg, size_t *len) {
+  return (upb_strview*)_upb_array_mutable_accessor(msg, UPB_SIZE(36, 72), len);
+}
+UPB_INLINE upb_strview* google_protobuf_FileDescriptorProto_resize_dependency(google_protobuf_FileDescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (upb_strview*)_upb_array_resize_accessor(msg, UPB_SIZE(36, 72), len, UPB_SIZE(8, 16), UPB_TYPE_STRING, arena);
+}
+UPB_INLINE bool google_protobuf_FileDescriptorProto_add_dependency(google_protobuf_FileDescriptorProto *msg, upb_strview val, upb_arena *arena) {
+  return _upb_array_append_accessor(
+      msg, UPB_SIZE(36, 72), UPB_SIZE(8, 16), UPB_TYPE_STRING, &val, arena);
+}
+UPB_INLINE google_protobuf_DescriptorProto** google_protobuf_FileDescriptorProto_mutable_message_type(google_protobuf_FileDescriptorProto *msg, size_t *len) {
+  return (google_protobuf_DescriptorProto**)_upb_array_mutable_accessor(msg, UPB_SIZE(40, 80), len);
+}
+UPB_INLINE google_protobuf_DescriptorProto** google_protobuf_FileDescriptorProto_resize_message_type(google_protobuf_FileDescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_DescriptorProto**)_upb_array_resize_accessor(msg, UPB_SIZE(40, 80), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_DescriptorProto* google_protobuf_FileDescriptorProto_add_message_type(google_protobuf_FileDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_DescriptorProto* sub = (struct google_protobuf_DescriptorProto*)upb_msg_new(&google_protobuf_DescriptorProto_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(40, 80), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE google_protobuf_EnumDescriptorProto** google_protobuf_FileDescriptorProto_mutable_enum_type(google_protobuf_FileDescriptorProto *msg, size_t *len) {
+  return (google_protobuf_EnumDescriptorProto**)_upb_array_mutable_accessor(msg, UPB_SIZE(44, 88), len);
+}
+UPB_INLINE google_protobuf_EnumDescriptorProto** google_protobuf_FileDescriptorProto_resize_enum_type(google_protobuf_FileDescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_EnumDescriptorProto**)_upb_array_resize_accessor(msg, UPB_SIZE(44, 88), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_EnumDescriptorProto* google_protobuf_FileDescriptorProto_add_enum_type(google_protobuf_FileDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_EnumDescriptorProto* sub = (struct google_protobuf_EnumDescriptorProto*)upb_msg_new(&google_protobuf_EnumDescriptorProto_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(44, 88), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE google_protobuf_ServiceDescriptorProto** google_protobuf_FileDescriptorProto_mutable_service(google_protobuf_FileDescriptorProto *msg, size_t *len) {
+  return (google_protobuf_ServiceDescriptorProto**)_upb_array_mutable_accessor(msg, UPB_SIZE(48, 96), len);
+}
+UPB_INLINE google_protobuf_ServiceDescriptorProto** google_protobuf_FileDescriptorProto_resize_service(google_protobuf_FileDescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_ServiceDescriptorProto**)_upb_array_resize_accessor(msg, UPB_SIZE(48, 96), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_ServiceDescriptorProto* google_protobuf_FileDescriptorProto_add_service(google_protobuf_FileDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_ServiceDescriptorProto* sub = (struct google_protobuf_ServiceDescriptorProto*)upb_msg_new(&google_protobuf_ServiceDescriptorProto_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(48, 96), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE google_protobuf_FieldDescriptorProto** google_protobuf_FileDescriptorProto_mutable_extension(google_protobuf_FileDescriptorProto *msg, size_t *len) {
+  return (google_protobuf_FieldDescriptorProto**)_upb_array_mutable_accessor(msg, UPB_SIZE(52, 104), len);
+}
+UPB_INLINE google_protobuf_FieldDescriptorProto** google_protobuf_FileDescriptorProto_resize_extension(google_protobuf_FileDescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_FieldDescriptorProto**)_upb_array_resize_accessor(msg, UPB_SIZE(52, 104), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_FieldDescriptorProto* google_protobuf_FileDescriptorProto_add_extension(google_protobuf_FileDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_FieldDescriptorProto* sub = (struct google_protobuf_FieldDescriptorProto*)upb_msg_new(&google_protobuf_FieldDescriptorProto_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(52, 104), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE void google_protobuf_FileDescriptorProto_set_options(google_protobuf_FileDescriptorProto *msg, google_protobuf_FileOptions* value) {
+  _upb_sethas(msg, 4);
+  UPB_FIELD_AT(msg, google_protobuf_FileOptions*, UPB_SIZE(28, 56)) = value;
+}
+UPB_INLINE struct google_protobuf_FileOptions* google_protobuf_FileDescriptorProto_mutable_options(google_protobuf_FileDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_FileOptions* sub = (struct google_protobuf_FileOptions*)google_protobuf_FileDescriptorProto_options(msg);
+  if (sub == NULL) {
+    sub = (struct google_protobuf_FileOptions*)upb_msg_new(&google_protobuf_FileOptions_msginit, arena);
+    if (!sub) return NULL;
+    google_protobuf_FileDescriptorProto_set_options(msg, sub);
+  }
+  return sub;
+}
+UPB_INLINE void google_protobuf_FileDescriptorProto_set_source_code_info(google_protobuf_FileDescriptorProto *msg, google_protobuf_SourceCodeInfo* value) {
+  _upb_sethas(msg, 5);
+  UPB_FIELD_AT(msg, google_protobuf_SourceCodeInfo*, UPB_SIZE(32, 64)) = value;
+}
+UPB_INLINE struct google_protobuf_SourceCodeInfo* google_protobuf_FileDescriptorProto_mutable_source_code_info(google_protobuf_FileDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_SourceCodeInfo* sub = (struct google_protobuf_SourceCodeInfo*)google_protobuf_FileDescriptorProto_source_code_info(msg);
+  if (sub == NULL) {
+    sub = (struct google_protobuf_SourceCodeInfo*)upb_msg_new(&google_protobuf_SourceCodeInfo_msginit, arena);
+    if (!sub) return NULL;
+    google_protobuf_FileDescriptorProto_set_source_code_info(msg, sub);
+  }
+  return sub;
+}
+UPB_INLINE int32_t* google_protobuf_FileDescriptorProto_mutable_public_dependency(google_protobuf_FileDescriptorProto *msg, size_t *len) {
+  return (int32_t*)_upb_array_mutable_accessor(msg, UPB_SIZE(56, 112), len);
+}
+UPB_INLINE int32_t* google_protobuf_FileDescriptorProto_resize_public_dependency(google_protobuf_FileDescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (int32_t*)_upb_array_resize_accessor(msg, UPB_SIZE(56, 112), len, UPB_SIZE(4, 4), UPB_TYPE_INT32, arena);
+}
+UPB_INLINE bool google_protobuf_FileDescriptorProto_add_public_dependency(google_protobuf_FileDescriptorProto *msg, int32_t val, upb_arena *arena) {
+  return _upb_array_append_accessor(
+      msg, UPB_SIZE(56, 112), UPB_SIZE(4, 4), UPB_TYPE_INT32, &val, arena);
+}
+UPB_INLINE int32_t* google_protobuf_FileDescriptorProto_mutable_weak_dependency(google_protobuf_FileDescriptorProto *msg, size_t *len) {
+  return (int32_t*)_upb_array_mutable_accessor(msg, UPB_SIZE(60, 120), len);
+}
+UPB_INLINE int32_t* google_protobuf_FileDescriptorProto_resize_weak_dependency(google_protobuf_FileDescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (int32_t*)_upb_array_resize_accessor(msg, UPB_SIZE(60, 120), len, UPB_SIZE(4, 4), UPB_TYPE_INT32, arena);
+}
+UPB_INLINE bool google_protobuf_FileDescriptorProto_add_weak_dependency(google_protobuf_FileDescriptorProto *msg, int32_t val, upb_arena *arena) {
+  return _upb_array_append_accessor(
+      msg, UPB_SIZE(60, 120), UPB_SIZE(4, 4), UPB_TYPE_INT32, &val, arena);
+}
+UPB_INLINE void google_protobuf_FileDescriptorProto_set_syntax(google_protobuf_FileDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 3);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(20, 40)) = value;
+}
+
+
+/* google.protobuf.DescriptorProto */
+
+UPB_INLINE google_protobuf_DescriptorProto *google_protobuf_DescriptorProto_new(upb_arena *arena) {
+  return (google_protobuf_DescriptorProto *)upb_msg_new(&google_protobuf_DescriptorProto_msginit, arena);
+}
+UPB_INLINE google_protobuf_DescriptorProto *google_protobuf_DescriptorProto_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_DescriptorProto *ret = google_protobuf_DescriptorProto_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_DescriptorProto_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_DescriptorProto_serialize(const google_protobuf_DescriptorProto *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_DescriptorProto_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_DescriptorProto_has_name(const google_protobuf_DescriptorProto *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE upb_strview google_protobuf_DescriptorProto_name(const google_protobuf_DescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)); }
+UPB_INLINE const google_protobuf_FieldDescriptorProto* const* google_protobuf_DescriptorProto_field(const google_protobuf_DescriptorProto *msg, size_t *len) { return (const google_protobuf_FieldDescriptorProto* const*)_upb_array_accessor(msg, UPB_SIZE(16, 32), len); }
+UPB_INLINE const google_protobuf_DescriptorProto* const* google_protobuf_DescriptorProto_nested_type(const google_protobuf_DescriptorProto *msg, size_t *len) { return (const google_protobuf_DescriptorProto* const*)_upb_array_accessor(msg, UPB_SIZE(20, 40), len); }
+UPB_INLINE const google_protobuf_EnumDescriptorProto* const* google_protobuf_DescriptorProto_enum_type(const google_protobuf_DescriptorProto *msg, size_t *len) { return (const google_protobuf_EnumDescriptorProto* const*)_upb_array_accessor(msg, UPB_SIZE(24, 48), len); }
+UPB_INLINE const google_protobuf_DescriptorProto_ExtensionRange* const* google_protobuf_DescriptorProto_extension_range(const google_protobuf_DescriptorProto *msg, size_t *len) { return (const google_protobuf_DescriptorProto_ExtensionRange* const*)_upb_array_accessor(msg, UPB_SIZE(28, 56), len); }
+UPB_INLINE const google_protobuf_FieldDescriptorProto* const* google_protobuf_DescriptorProto_extension(const google_protobuf_DescriptorProto *msg, size_t *len) { return (const google_protobuf_FieldDescriptorProto* const*)_upb_array_accessor(msg, UPB_SIZE(32, 64), len); }
+UPB_INLINE bool google_protobuf_DescriptorProto_has_options(const google_protobuf_DescriptorProto *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE const google_protobuf_MessageOptions* google_protobuf_DescriptorProto_options(const google_protobuf_DescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_MessageOptions*, UPB_SIZE(12, 24)); }
+UPB_INLINE const google_protobuf_OneofDescriptorProto* const* google_protobuf_DescriptorProto_oneof_decl(const google_protobuf_DescriptorProto *msg, size_t *len) { return (const google_protobuf_OneofDescriptorProto* const*)_upb_array_accessor(msg, UPB_SIZE(36, 72), len); }
+UPB_INLINE const google_protobuf_DescriptorProto_ReservedRange* const* google_protobuf_DescriptorProto_reserved_range(const google_protobuf_DescriptorProto *msg, size_t *len) { return (const google_protobuf_DescriptorProto_ReservedRange* const*)_upb_array_accessor(msg, UPB_SIZE(40, 80), len); }
+UPB_INLINE upb_strview const* google_protobuf_DescriptorProto_reserved_name(const google_protobuf_DescriptorProto *msg, size_t *len) { return (upb_strview const*)_upb_array_accessor(msg, UPB_SIZE(44, 88), len); }
+
+UPB_INLINE void google_protobuf_DescriptorProto_set_name(google_protobuf_DescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)) = value;
+}
+UPB_INLINE google_protobuf_FieldDescriptorProto** google_protobuf_DescriptorProto_mutable_field(google_protobuf_DescriptorProto *msg, size_t *len) {
+  return (google_protobuf_FieldDescriptorProto**)_upb_array_mutable_accessor(msg, UPB_SIZE(16, 32), len);
+}
+UPB_INLINE google_protobuf_FieldDescriptorProto** google_protobuf_DescriptorProto_resize_field(google_protobuf_DescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_FieldDescriptorProto**)_upb_array_resize_accessor(msg, UPB_SIZE(16, 32), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_FieldDescriptorProto* google_protobuf_DescriptorProto_add_field(google_protobuf_DescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_FieldDescriptorProto* sub = (struct google_protobuf_FieldDescriptorProto*)upb_msg_new(&google_protobuf_FieldDescriptorProto_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(16, 32), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE google_protobuf_DescriptorProto** google_protobuf_DescriptorProto_mutable_nested_type(google_protobuf_DescriptorProto *msg, size_t *len) {
+  return (google_protobuf_DescriptorProto**)_upb_array_mutable_accessor(msg, UPB_SIZE(20, 40), len);
+}
+UPB_INLINE google_protobuf_DescriptorProto** google_protobuf_DescriptorProto_resize_nested_type(google_protobuf_DescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_DescriptorProto**)_upb_array_resize_accessor(msg, UPB_SIZE(20, 40), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_DescriptorProto* google_protobuf_DescriptorProto_add_nested_type(google_protobuf_DescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_DescriptorProto* sub = (struct google_protobuf_DescriptorProto*)upb_msg_new(&google_protobuf_DescriptorProto_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(20, 40), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE google_protobuf_EnumDescriptorProto** google_protobuf_DescriptorProto_mutable_enum_type(google_protobuf_DescriptorProto *msg, size_t *len) {
+  return (google_protobuf_EnumDescriptorProto**)_upb_array_mutable_accessor(msg, UPB_SIZE(24, 48), len);
+}
+UPB_INLINE google_protobuf_EnumDescriptorProto** google_protobuf_DescriptorProto_resize_enum_type(google_protobuf_DescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_EnumDescriptorProto**)_upb_array_resize_accessor(msg, UPB_SIZE(24, 48), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_EnumDescriptorProto* google_protobuf_DescriptorProto_add_enum_type(google_protobuf_DescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_EnumDescriptorProto* sub = (struct google_protobuf_EnumDescriptorProto*)upb_msg_new(&google_protobuf_EnumDescriptorProto_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(24, 48), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE google_protobuf_DescriptorProto_ExtensionRange** google_protobuf_DescriptorProto_mutable_extension_range(google_protobuf_DescriptorProto *msg, size_t *len) {
+  return (google_protobuf_DescriptorProto_ExtensionRange**)_upb_array_mutable_accessor(msg, UPB_SIZE(28, 56), len);
+}
+UPB_INLINE google_protobuf_DescriptorProto_ExtensionRange** google_protobuf_DescriptorProto_resize_extension_range(google_protobuf_DescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_DescriptorProto_ExtensionRange**)_upb_array_resize_accessor(msg, UPB_SIZE(28, 56), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_DescriptorProto_ExtensionRange* google_protobuf_DescriptorProto_add_extension_range(google_protobuf_DescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_DescriptorProto_ExtensionRange* sub = (struct google_protobuf_DescriptorProto_ExtensionRange*)upb_msg_new(&google_protobuf_DescriptorProto_ExtensionRange_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(28, 56), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE google_protobuf_FieldDescriptorProto** google_protobuf_DescriptorProto_mutable_extension(google_protobuf_DescriptorProto *msg, size_t *len) {
+  return (google_protobuf_FieldDescriptorProto**)_upb_array_mutable_accessor(msg, UPB_SIZE(32, 64), len);
+}
+UPB_INLINE google_protobuf_FieldDescriptorProto** google_protobuf_DescriptorProto_resize_extension(google_protobuf_DescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_FieldDescriptorProto**)_upb_array_resize_accessor(msg, UPB_SIZE(32, 64), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_FieldDescriptorProto* google_protobuf_DescriptorProto_add_extension(google_protobuf_DescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_FieldDescriptorProto* sub = (struct google_protobuf_FieldDescriptorProto*)upb_msg_new(&google_protobuf_FieldDescriptorProto_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(32, 64), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE void google_protobuf_DescriptorProto_set_options(google_protobuf_DescriptorProto *msg, google_protobuf_MessageOptions* value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, google_protobuf_MessageOptions*, UPB_SIZE(12, 24)) = value;
+}
+UPB_INLINE struct google_protobuf_MessageOptions* google_protobuf_DescriptorProto_mutable_options(google_protobuf_DescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_MessageOptions* sub = (struct google_protobuf_MessageOptions*)google_protobuf_DescriptorProto_options(msg);
+  if (sub == NULL) {
+    sub = (struct google_protobuf_MessageOptions*)upb_msg_new(&google_protobuf_MessageOptions_msginit, arena);
+    if (!sub) return NULL;
+    google_protobuf_DescriptorProto_set_options(msg, sub);
+  }
+  return sub;
+}
+UPB_INLINE google_protobuf_OneofDescriptorProto** google_protobuf_DescriptorProto_mutable_oneof_decl(google_protobuf_DescriptorProto *msg, size_t *len) {
+  return (google_protobuf_OneofDescriptorProto**)_upb_array_mutable_accessor(msg, UPB_SIZE(36, 72), len);
+}
+UPB_INLINE google_protobuf_OneofDescriptorProto** google_protobuf_DescriptorProto_resize_oneof_decl(google_protobuf_DescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_OneofDescriptorProto**)_upb_array_resize_accessor(msg, UPB_SIZE(36, 72), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_OneofDescriptorProto* google_protobuf_DescriptorProto_add_oneof_decl(google_protobuf_DescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_OneofDescriptorProto* sub = (struct google_protobuf_OneofDescriptorProto*)upb_msg_new(&google_protobuf_OneofDescriptorProto_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(36, 72), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE google_protobuf_DescriptorProto_ReservedRange** google_protobuf_DescriptorProto_mutable_reserved_range(google_protobuf_DescriptorProto *msg, size_t *len) {
+  return (google_protobuf_DescriptorProto_ReservedRange**)_upb_array_mutable_accessor(msg, UPB_SIZE(40, 80), len);
+}
+UPB_INLINE google_protobuf_DescriptorProto_ReservedRange** google_protobuf_DescriptorProto_resize_reserved_range(google_protobuf_DescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_DescriptorProto_ReservedRange**)_upb_array_resize_accessor(msg, UPB_SIZE(40, 80), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_DescriptorProto_ReservedRange* google_protobuf_DescriptorProto_add_reserved_range(google_protobuf_DescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_DescriptorProto_ReservedRange* sub = (struct google_protobuf_DescriptorProto_ReservedRange*)upb_msg_new(&google_protobuf_DescriptorProto_ReservedRange_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(40, 80), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE upb_strview* google_protobuf_DescriptorProto_mutable_reserved_name(google_protobuf_DescriptorProto *msg, size_t *len) {
+  return (upb_strview*)_upb_array_mutable_accessor(msg, UPB_SIZE(44, 88), len);
+}
+UPB_INLINE upb_strview* google_protobuf_DescriptorProto_resize_reserved_name(google_protobuf_DescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (upb_strview*)_upb_array_resize_accessor(msg, UPB_SIZE(44, 88), len, UPB_SIZE(8, 16), UPB_TYPE_STRING, arena);
+}
+UPB_INLINE bool google_protobuf_DescriptorProto_add_reserved_name(google_protobuf_DescriptorProto *msg, upb_strview val, upb_arena *arena) {
+  return _upb_array_append_accessor(
+      msg, UPB_SIZE(44, 88), UPB_SIZE(8, 16), UPB_TYPE_STRING, &val, arena);
+}
+
+
+/* google.protobuf.DescriptorProto.ExtensionRange */
+
+UPB_INLINE google_protobuf_DescriptorProto_ExtensionRange *google_protobuf_DescriptorProto_ExtensionRange_new(upb_arena *arena) {
+  return (google_protobuf_DescriptorProto_ExtensionRange *)upb_msg_new(&google_protobuf_DescriptorProto_ExtensionRange_msginit, arena);
+}
+UPB_INLINE google_protobuf_DescriptorProto_ExtensionRange *google_protobuf_DescriptorProto_ExtensionRange_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_DescriptorProto_ExtensionRange *ret = google_protobuf_DescriptorProto_ExtensionRange_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_DescriptorProto_ExtensionRange_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_DescriptorProto_ExtensionRange_serialize(const google_protobuf_DescriptorProto_ExtensionRange *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_DescriptorProto_ExtensionRange_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_DescriptorProto_ExtensionRange_has_start(const google_protobuf_DescriptorProto_ExtensionRange *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE int32_t google_protobuf_DescriptorProto_ExtensionRange_start(const google_protobuf_DescriptorProto_ExtensionRange *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)); }
+UPB_INLINE bool google_protobuf_DescriptorProto_ExtensionRange_has_end(const google_protobuf_DescriptorProto_ExtensionRange *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE int32_t google_protobuf_DescriptorProto_ExtensionRange_end(const google_protobuf_DescriptorProto_ExtensionRange *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)); }
+UPB_INLINE bool google_protobuf_DescriptorProto_ExtensionRange_has_options(const google_protobuf_DescriptorProto_ExtensionRange *msg) { return _upb_has_field(msg, 3); }
+UPB_INLINE const google_protobuf_ExtensionRangeOptions* google_protobuf_DescriptorProto_ExtensionRange_options(const google_protobuf_DescriptorProto_ExtensionRange *msg) { return UPB_FIELD_AT(msg, const google_protobuf_ExtensionRangeOptions*, UPB_SIZE(12, 16)); }
+
+UPB_INLINE void google_protobuf_DescriptorProto_ExtensionRange_set_start(google_protobuf_DescriptorProto_ExtensionRange *msg, int32_t value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)) = value;
+}
+UPB_INLINE void google_protobuf_DescriptorProto_ExtensionRange_set_end(google_protobuf_DescriptorProto_ExtensionRange *msg, int32_t value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)) = value;
+}
+UPB_INLINE void google_protobuf_DescriptorProto_ExtensionRange_set_options(google_protobuf_DescriptorProto_ExtensionRange *msg, google_protobuf_ExtensionRangeOptions* value) {
+  _upb_sethas(msg, 3);
+  UPB_FIELD_AT(msg, google_protobuf_ExtensionRangeOptions*, UPB_SIZE(12, 16)) = value;
+}
+UPB_INLINE struct google_protobuf_ExtensionRangeOptions* google_protobuf_DescriptorProto_ExtensionRange_mutable_options(google_protobuf_DescriptorProto_ExtensionRange *msg, upb_arena *arena) {
+  struct google_protobuf_ExtensionRangeOptions* sub = (struct google_protobuf_ExtensionRangeOptions*)google_protobuf_DescriptorProto_ExtensionRange_options(msg);
+  if (sub == NULL) {
+    sub = (struct google_protobuf_ExtensionRangeOptions*)upb_msg_new(&google_protobuf_ExtensionRangeOptions_msginit, arena);
+    if (!sub) return NULL;
+    google_protobuf_DescriptorProto_ExtensionRange_set_options(msg, sub);
+  }
+  return sub;
+}
+
+
+/* google.protobuf.DescriptorProto.ReservedRange */
+
+UPB_INLINE google_protobuf_DescriptorProto_ReservedRange *google_protobuf_DescriptorProto_ReservedRange_new(upb_arena *arena) {
+  return (google_protobuf_DescriptorProto_ReservedRange *)upb_msg_new(&google_protobuf_DescriptorProto_ReservedRange_msginit, arena);
+}
+UPB_INLINE google_protobuf_DescriptorProto_ReservedRange *google_protobuf_DescriptorProto_ReservedRange_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_DescriptorProto_ReservedRange *ret = google_protobuf_DescriptorProto_ReservedRange_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_DescriptorProto_ReservedRange_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_DescriptorProto_ReservedRange_serialize(const google_protobuf_DescriptorProto_ReservedRange *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_DescriptorProto_ReservedRange_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_DescriptorProto_ReservedRange_has_start(const google_protobuf_DescriptorProto_ReservedRange *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE int32_t google_protobuf_DescriptorProto_ReservedRange_start(const google_protobuf_DescriptorProto_ReservedRange *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)); }
+UPB_INLINE bool google_protobuf_DescriptorProto_ReservedRange_has_end(const google_protobuf_DescriptorProto_ReservedRange *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE int32_t google_protobuf_DescriptorProto_ReservedRange_end(const google_protobuf_DescriptorProto_ReservedRange *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)); }
+
+UPB_INLINE void google_protobuf_DescriptorProto_ReservedRange_set_start(google_protobuf_DescriptorProto_ReservedRange *msg, int32_t value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)) = value;
+}
+UPB_INLINE void google_protobuf_DescriptorProto_ReservedRange_set_end(google_protobuf_DescriptorProto_ReservedRange *msg, int32_t value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)) = value;
+}
+
+
+/* google.protobuf.ExtensionRangeOptions */
+
+UPB_INLINE google_protobuf_ExtensionRangeOptions *google_protobuf_ExtensionRangeOptions_new(upb_arena *arena) {
+  return (google_protobuf_ExtensionRangeOptions *)upb_msg_new(&google_protobuf_ExtensionRangeOptions_msginit, arena);
+}
+UPB_INLINE google_protobuf_ExtensionRangeOptions *google_protobuf_ExtensionRangeOptions_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_ExtensionRangeOptions *ret = google_protobuf_ExtensionRangeOptions_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_ExtensionRangeOptions_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_ExtensionRangeOptions_serialize(const google_protobuf_ExtensionRangeOptions *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_ExtensionRangeOptions_msginit, arena, len);
+}
+
+UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_ExtensionRangeOptions_uninterpreted_option(const google_protobuf_ExtensionRangeOptions *msg, size_t *len) { return (const google_protobuf_UninterpretedOption* const*)_upb_array_accessor(msg, UPB_SIZE(0, 0), len); }
+
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_ExtensionRangeOptions_mutable_uninterpreted_option(google_protobuf_ExtensionRangeOptions *msg, size_t *len) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_mutable_accessor(msg, UPB_SIZE(0, 0), len);
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_ExtensionRangeOptions_resize_uninterpreted_option(google_protobuf_ExtensionRangeOptions *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_resize_accessor(msg, UPB_SIZE(0, 0), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_ExtensionRangeOptions_add_uninterpreted_option(google_protobuf_ExtensionRangeOptions *msg, upb_arena *arena) {
+  struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)upb_msg_new(&google_protobuf_UninterpretedOption_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(0, 0), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+
+
+/* google.protobuf.FieldDescriptorProto */
+
+UPB_INLINE google_protobuf_FieldDescriptorProto *google_protobuf_FieldDescriptorProto_new(upb_arena *arena) {
+  return (google_protobuf_FieldDescriptorProto *)upb_msg_new(&google_protobuf_FieldDescriptorProto_msginit, arena);
+}
+UPB_INLINE google_protobuf_FieldDescriptorProto *google_protobuf_FieldDescriptorProto_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_FieldDescriptorProto *ret = google_protobuf_FieldDescriptorProto_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_FieldDescriptorProto_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_FieldDescriptorProto_serialize(const google_protobuf_FieldDescriptorProto *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_FieldDescriptorProto_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_FieldDescriptorProto_has_name(const google_protobuf_FieldDescriptorProto *msg) { return _upb_has_field(msg, 5); }
+UPB_INLINE upb_strview google_protobuf_FieldDescriptorProto_name(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(32, 32)); }
+UPB_INLINE bool google_protobuf_FieldDescriptorProto_has_extendee(const google_protobuf_FieldDescriptorProto *msg) { return _upb_has_field(msg, 6); }
+UPB_INLINE upb_strview google_protobuf_FieldDescriptorProto_extendee(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(40, 48)); }
+UPB_INLINE bool google_protobuf_FieldDescriptorProto_has_number(const google_protobuf_FieldDescriptorProto *msg) { return _upb_has_field(msg, 3); }
+UPB_INLINE int32_t google_protobuf_FieldDescriptorProto_number(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(24, 24)); }
+UPB_INLINE bool google_protobuf_FieldDescriptorProto_has_label(const google_protobuf_FieldDescriptorProto *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE google_protobuf_FieldDescriptorProto_Label google_protobuf_FieldDescriptorProto_label(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, google_protobuf_FieldDescriptorProto_Label, UPB_SIZE(8, 8)); }
+UPB_INLINE bool google_protobuf_FieldDescriptorProto_has_type(const google_protobuf_FieldDescriptorProto *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE google_protobuf_FieldDescriptorProto_Type google_protobuf_FieldDescriptorProto_type(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, google_protobuf_FieldDescriptorProto_Type, UPB_SIZE(16, 16)); }
+UPB_INLINE bool google_protobuf_FieldDescriptorProto_has_type_name(const google_protobuf_FieldDescriptorProto *msg) { return _upb_has_field(msg, 7); }
+UPB_INLINE upb_strview google_protobuf_FieldDescriptorProto_type_name(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(48, 64)); }
+UPB_INLINE bool google_protobuf_FieldDescriptorProto_has_default_value(const google_protobuf_FieldDescriptorProto *msg) { return _upb_has_field(msg, 8); }
+UPB_INLINE upb_strview google_protobuf_FieldDescriptorProto_default_value(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(56, 80)); }
+UPB_INLINE bool google_protobuf_FieldDescriptorProto_has_options(const google_protobuf_FieldDescriptorProto *msg) { return _upb_has_field(msg, 10); }
+UPB_INLINE const google_protobuf_FieldOptions* google_protobuf_FieldDescriptorProto_options(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_FieldOptions*, UPB_SIZE(72, 112)); }
+UPB_INLINE bool google_protobuf_FieldDescriptorProto_has_oneof_index(const google_protobuf_FieldDescriptorProto *msg) { return _upb_has_field(msg, 4); }
+UPB_INLINE int32_t google_protobuf_FieldDescriptorProto_oneof_index(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(28, 28)); }
+UPB_INLINE bool google_protobuf_FieldDescriptorProto_has_json_name(const google_protobuf_FieldDescriptorProto *msg) { return _upb_has_field(msg, 9); }
+UPB_INLINE upb_strview google_protobuf_FieldDescriptorProto_json_name(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(64, 96)); }
+
+UPB_INLINE void google_protobuf_FieldDescriptorProto_set_name(google_protobuf_FieldDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 5);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(32, 32)) = value;
+}
+UPB_INLINE void google_protobuf_FieldDescriptorProto_set_extendee(google_protobuf_FieldDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 6);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(40, 48)) = value;
+}
+UPB_INLINE void google_protobuf_FieldDescriptorProto_set_number(google_protobuf_FieldDescriptorProto *msg, int32_t value) {
+  _upb_sethas(msg, 3);
+  UPB_FIELD_AT(msg, int32_t, UPB_SIZE(24, 24)) = value;
+}
+UPB_INLINE void google_protobuf_FieldDescriptorProto_set_label(google_protobuf_FieldDescriptorProto *msg, google_protobuf_FieldDescriptorProto_Label value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, google_protobuf_FieldDescriptorProto_Label, UPB_SIZE(8, 8)) = value;
+}
+UPB_INLINE void google_protobuf_FieldDescriptorProto_set_type(google_protobuf_FieldDescriptorProto *msg, google_protobuf_FieldDescriptorProto_Type value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, google_protobuf_FieldDescriptorProto_Type, UPB_SIZE(16, 16)) = value;
+}
+UPB_INLINE void google_protobuf_FieldDescriptorProto_set_type_name(google_protobuf_FieldDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 7);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(48, 64)) = value;
+}
+UPB_INLINE void google_protobuf_FieldDescriptorProto_set_default_value(google_protobuf_FieldDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 8);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(56, 80)) = value;
+}
+UPB_INLINE void google_protobuf_FieldDescriptorProto_set_options(google_protobuf_FieldDescriptorProto *msg, google_protobuf_FieldOptions* value) {
+  _upb_sethas(msg, 10);
+  UPB_FIELD_AT(msg, google_protobuf_FieldOptions*, UPB_SIZE(72, 112)) = value;
+}
+UPB_INLINE struct google_protobuf_FieldOptions* google_protobuf_FieldDescriptorProto_mutable_options(google_protobuf_FieldDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_FieldOptions* sub = (struct google_protobuf_FieldOptions*)google_protobuf_FieldDescriptorProto_options(msg);
+  if (sub == NULL) {
+    sub = (struct google_protobuf_FieldOptions*)upb_msg_new(&google_protobuf_FieldOptions_msginit, arena);
+    if (!sub) return NULL;
+    google_protobuf_FieldDescriptorProto_set_options(msg, sub);
+  }
+  return sub;
+}
+UPB_INLINE void google_protobuf_FieldDescriptorProto_set_oneof_index(google_protobuf_FieldDescriptorProto *msg, int32_t value) {
+  _upb_sethas(msg, 4);
+  UPB_FIELD_AT(msg, int32_t, UPB_SIZE(28, 28)) = value;
+}
+UPB_INLINE void google_protobuf_FieldDescriptorProto_set_json_name(google_protobuf_FieldDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 9);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(64, 96)) = value;
+}
+
+
+/* google.protobuf.OneofDescriptorProto */
+
+UPB_INLINE google_protobuf_OneofDescriptorProto *google_protobuf_OneofDescriptorProto_new(upb_arena *arena) {
+  return (google_protobuf_OneofDescriptorProto *)upb_msg_new(&google_protobuf_OneofDescriptorProto_msginit, arena);
+}
+UPB_INLINE google_protobuf_OneofDescriptorProto *google_protobuf_OneofDescriptorProto_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_OneofDescriptorProto *ret = google_protobuf_OneofDescriptorProto_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_OneofDescriptorProto_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_OneofDescriptorProto_serialize(const google_protobuf_OneofDescriptorProto *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_OneofDescriptorProto_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_OneofDescriptorProto_has_name(const google_protobuf_OneofDescriptorProto *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE upb_strview google_protobuf_OneofDescriptorProto_name(const google_protobuf_OneofDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)); }
+UPB_INLINE bool google_protobuf_OneofDescriptorProto_has_options(const google_protobuf_OneofDescriptorProto *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE const google_protobuf_OneofOptions* google_protobuf_OneofDescriptorProto_options(const google_protobuf_OneofDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_OneofOptions*, UPB_SIZE(12, 24)); }
+
+UPB_INLINE void google_protobuf_OneofDescriptorProto_set_name(google_protobuf_OneofDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)) = value;
+}
+UPB_INLINE void google_protobuf_OneofDescriptorProto_set_options(google_protobuf_OneofDescriptorProto *msg, google_protobuf_OneofOptions* value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, google_protobuf_OneofOptions*, UPB_SIZE(12, 24)) = value;
+}
+UPB_INLINE struct google_protobuf_OneofOptions* google_protobuf_OneofDescriptorProto_mutable_options(google_protobuf_OneofDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_OneofOptions* sub = (struct google_protobuf_OneofOptions*)google_protobuf_OneofDescriptorProto_options(msg);
+  if (sub == NULL) {
+    sub = (struct google_protobuf_OneofOptions*)upb_msg_new(&google_protobuf_OneofOptions_msginit, arena);
+    if (!sub) return NULL;
+    google_protobuf_OneofDescriptorProto_set_options(msg, sub);
+  }
+  return sub;
+}
+
+
+/* google.protobuf.EnumDescriptorProto */
+
+UPB_INLINE google_protobuf_EnumDescriptorProto *google_protobuf_EnumDescriptorProto_new(upb_arena *arena) {
+  return (google_protobuf_EnumDescriptorProto *)upb_msg_new(&google_protobuf_EnumDescriptorProto_msginit, arena);
+}
+UPB_INLINE google_protobuf_EnumDescriptorProto *google_protobuf_EnumDescriptorProto_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_EnumDescriptorProto *ret = google_protobuf_EnumDescriptorProto_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_EnumDescriptorProto_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_EnumDescriptorProto_serialize(const google_protobuf_EnumDescriptorProto *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_EnumDescriptorProto_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_EnumDescriptorProto_has_name(const google_protobuf_EnumDescriptorProto *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE upb_strview google_protobuf_EnumDescriptorProto_name(const google_protobuf_EnumDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)); }
+UPB_INLINE const google_protobuf_EnumValueDescriptorProto* const* google_protobuf_EnumDescriptorProto_value(const google_protobuf_EnumDescriptorProto *msg, size_t *len) { return (const google_protobuf_EnumValueDescriptorProto* const*)_upb_array_accessor(msg, UPB_SIZE(16, 32), len); }
+UPB_INLINE bool google_protobuf_EnumDescriptorProto_has_options(const google_protobuf_EnumDescriptorProto *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE const google_protobuf_EnumOptions* google_protobuf_EnumDescriptorProto_options(const google_protobuf_EnumDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_EnumOptions*, UPB_SIZE(12, 24)); }
+UPB_INLINE const google_protobuf_EnumDescriptorProto_EnumReservedRange* const* google_protobuf_EnumDescriptorProto_reserved_range(const google_protobuf_EnumDescriptorProto *msg, size_t *len) { return (const google_protobuf_EnumDescriptorProto_EnumReservedRange* const*)_upb_array_accessor(msg, UPB_SIZE(20, 40), len); }
+UPB_INLINE upb_strview const* google_protobuf_EnumDescriptorProto_reserved_name(const google_protobuf_EnumDescriptorProto *msg, size_t *len) { return (upb_strview const*)_upb_array_accessor(msg, UPB_SIZE(24, 48), len); }
+
+UPB_INLINE void google_protobuf_EnumDescriptorProto_set_name(google_protobuf_EnumDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)) = value;
+}
+UPB_INLINE google_protobuf_EnumValueDescriptorProto** google_protobuf_EnumDescriptorProto_mutable_value(google_protobuf_EnumDescriptorProto *msg, size_t *len) {
+  return (google_protobuf_EnumValueDescriptorProto**)_upb_array_mutable_accessor(msg, UPB_SIZE(16, 32), len);
+}
+UPB_INLINE google_protobuf_EnumValueDescriptorProto** google_protobuf_EnumDescriptorProto_resize_value(google_protobuf_EnumDescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_EnumValueDescriptorProto**)_upb_array_resize_accessor(msg, UPB_SIZE(16, 32), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_EnumValueDescriptorProto* google_protobuf_EnumDescriptorProto_add_value(google_protobuf_EnumDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_EnumValueDescriptorProto* sub = (struct google_protobuf_EnumValueDescriptorProto*)upb_msg_new(&google_protobuf_EnumValueDescriptorProto_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(16, 32), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE void google_protobuf_EnumDescriptorProto_set_options(google_protobuf_EnumDescriptorProto *msg, google_protobuf_EnumOptions* value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, google_protobuf_EnumOptions*, UPB_SIZE(12, 24)) = value;
+}
+UPB_INLINE struct google_protobuf_EnumOptions* google_protobuf_EnumDescriptorProto_mutable_options(google_protobuf_EnumDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_EnumOptions* sub = (struct google_protobuf_EnumOptions*)google_protobuf_EnumDescriptorProto_options(msg);
+  if (sub == NULL) {
+    sub = (struct google_protobuf_EnumOptions*)upb_msg_new(&google_protobuf_EnumOptions_msginit, arena);
+    if (!sub) return NULL;
+    google_protobuf_EnumDescriptorProto_set_options(msg, sub);
+  }
+  return sub;
+}
+UPB_INLINE google_protobuf_EnumDescriptorProto_EnumReservedRange** google_protobuf_EnumDescriptorProto_mutable_reserved_range(google_protobuf_EnumDescriptorProto *msg, size_t *len) {
+  return (google_protobuf_EnumDescriptorProto_EnumReservedRange**)_upb_array_mutable_accessor(msg, UPB_SIZE(20, 40), len);
+}
+UPB_INLINE google_protobuf_EnumDescriptorProto_EnumReservedRange** google_protobuf_EnumDescriptorProto_resize_reserved_range(google_protobuf_EnumDescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_EnumDescriptorProto_EnumReservedRange**)_upb_array_resize_accessor(msg, UPB_SIZE(20, 40), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_EnumDescriptorProto_EnumReservedRange* google_protobuf_EnumDescriptorProto_add_reserved_range(google_protobuf_EnumDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_EnumDescriptorProto_EnumReservedRange* sub = (struct google_protobuf_EnumDescriptorProto_EnumReservedRange*)upb_msg_new(&google_protobuf_EnumDescriptorProto_EnumReservedRange_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(20, 40), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE upb_strview* google_protobuf_EnumDescriptorProto_mutable_reserved_name(google_protobuf_EnumDescriptorProto *msg, size_t *len) {
+  return (upb_strview*)_upb_array_mutable_accessor(msg, UPB_SIZE(24, 48), len);
+}
+UPB_INLINE upb_strview* google_protobuf_EnumDescriptorProto_resize_reserved_name(google_protobuf_EnumDescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (upb_strview*)_upb_array_resize_accessor(msg, UPB_SIZE(24, 48), len, UPB_SIZE(8, 16), UPB_TYPE_STRING, arena);
+}
+UPB_INLINE bool google_protobuf_EnumDescriptorProto_add_reserved_name(google_protobuf_EnumDescriptorProto *msg, upb_strview val, upb_arena *arena) {
+  return _upb_array_append_accessor(
+      msg, UPB_SIZE(24, 48), UPB_SIZE(8, 16), UPB_TYPE_STRING, &val, arena);
+}
+
+
+/* google.protobuf.EnumDescriptorProto.EnumReservedRange */
+
+UPB_INLINE google_protobuf_EnumDescriptorProto_EnumReservedRange *google_protobuf_EnumDescriptorProto_EnumReservedRange_new(upb_arena *arena) {
+  return (google_protobuf_EnumDescriptorProto_EnumReservedRange *)upb_msg_new(&google_protobuf_EnumDescriptorProto_EnumReservedRange_msginit, arena);
+}
+UPB_INLINE google_protobuf_EnumDescriptorProto_EnumReservedRange *google_protobuf_EnumDescriptorProto_EnumReservedRange_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_EnumDescriptorProto_EnumReservedRange *ret = google_protobuf_EnumDescriptorProto_EnumReservedRange_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_EnumDescriptorProto_EnumReservedRange_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_EnumDescriptorProto_EnumReservedRange_serialize(const google_protobuf_EnumDescriptorProto_EnumReservedRange *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_EnumDescriptorProto_EnumReservedRange_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_EnumDescriptorProto_EnumReservedRange_has_start(const google_protobuf_EnumDescriptorProto_EnumReservedRange *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE int32_t google_protobuf_EnumDescriptorProto_EnumReservedRange_start(const google_protobuf_EnumDescriptorProto_EnumReservedRange *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)); }
+UPB_INLINE bool google_protobuf_EnumDescriptorProto_EnumReservedRange_has_end(const google_protobuf_EnumDescriptorProto_EnumReservedRange *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE int32_t google_protobuf_EnumDescriptorProto_EnumReservedRange_end(const google_protobuf_EnumDescriptorProto_EnumReservedRange *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)); }
+
+UPB_INLINE void google_protobuf_EnumDescriptorProto_EnumReservedRange_set_start(google_protobuf_EnumDescriptorProto_EnumReservedRange *msg, int32_t value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)) = value;
+}
+UPB_INLINE void google_protobuf_EnumDescriptorProto_EnumReservedRange_set_end(google_protobuf_EnumDescriptorProto_EnumReservedRange *msg, int32_t value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)) = value;
+}
+
+
+/* google.protobuf.EnumValueDescriptorProto */
+
+UPB_INLINE google_protobuf_EnumValueDescriptorProto *google_protobuf_EnumValueDescriptorProto_new(upb_arena *arena) {
+  return (google_protobuf_EnumValueDescriptorProto *)upb_msg_new(&google_protobuf_EnumValueDescriptorProto_msginit, arena);
+}
+UPB_INLINE google_protobuf_EnumValueDescriptorProto *google_protobuf_EnumValueDescriptorProto_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_EnumValueDescriptorProto *ret = google_protobuf_EnumValueDescriptorProto_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_EnumValueDescriptorProto_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_EnumValueDescriptorProto_serialize(const google_protobuf_EnumValueDescriptorProto *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_EnumValueDescriptorProto_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_EnumValueDescriptorProto_has_name(const google_protobuf_EnumValueDescriptorProto *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE upb_strview google_protobuf_EnumValueDescriptorProto_name(const google_protobuf_EnumValueDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(8, 8)); }
+UPB_INLINE bool google_protobuf_EnumValueDescriptorProto_has_number(const google_protobuf_EnumValueDescriptorProto *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE int32_t google_protobuf_EnumValueDescriptorProto_number(const google_protobuf_EnumValueDescriptorProto *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)); }
+UPB_INLINE bool google_protobuf_EnumValueDescriptorProto_has_options(const google_protobuf_EnumValueDescriptorProto *msg) { return _upb_has_field(msg, 3); }
+UPB_INLINE const google_protobuf_EnumValueOptions* google_protobuf_EnumValueDescriptorProto_options(const google_protobuf_EnumValueDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_EnumValueOptions*, UPB_SIZE(16, 24)); }
+
+UPB_INLINE void google_protobuf_EnumValueDescriptorProto_set_name(google_protobuf_EnumValueDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(8, 8)) = value;
+}
+UPB_INLINE void google_protobuf_EnumValueDescriptorProto_set_number(google_protobuf_EnumValueDescriptorProto *msg, int32_t value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)) = value;
+}
+UPB_INLINE void google_protobuf_EnumValueDescriptorProto_set_options(google_protobuf_EnumValueDescriptorProto *msg, google_protobuf_EnumValueOptions* value) {
+  _upb_sethas(msg, 3);
+  UPB_FIELD_AT(msg, google_protobuf_EnumValueOptions*, UPB_SIZE(16, 24)) = value;
+}
+UPB_INLINE struct google_protobuf_EnumValueOptions* google_protobuf_EnumValueDescriptorProto_mutable_options(google_protobuf_EnumValueDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_EnumValueOptions* sub = (struct google_protobuf_EnumValueOptions*)google_protobuf_EnumValueDescriptorProto_options(msg);
+  if (sub == NULL) {
+    sub = (struct google_protobuf_EnumValueOptions*)upb_msg_new(&google_protobuf_EnumValueOptions_msginit, arena);
+    if (!sub) return NULL;
+    google_protobuf_EnumValueDescriptorProto_set_options(msg, sub);
+  }
+  return sub;
+}
+
+
+/* google.protobuf.ServiceDescriptorProto */
+
+UPB_INLINE google_protobuf_ServiceDescriptorProto *google_protobuf_ServiceDescriptorProto_new(upb_arena *arena) {
+  return (google_protobuf_ServiceDescriptorProto *)upb_msg_new(&google_protobuf_ServiceDescriptorProto_msginit, arena);
+}
+UPB_INLINE google_protobuf_ServiceDescriptorProto *google_protobuf_ServiceDescriptorProto_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_ServiceDescriptorProto *ret = google_protobuf_ServiceDescriptorProto_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_ServiceDescriptorProto_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_ServiceDescriptorProto_serialize(const google_protobuf_ServiceDescriptorProto *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_ServiceDescriptorProto_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_ServiceDescriptorProto_has_name(const google_protobuf_ServiceDescriptorProto *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE upb_strview google_protobuf_ServiceDescriptorProto_name(const google_protobuf_ServiceDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)); }
+UPB_INLINE const google_protobuf_MethodDescriptorProto* const* google_protobuf_ServiceDescriptorProto_method(const google_protobuf_ServiceDescriptorProto *msg, size_t *len) { return (const google_protobuf_MethodDescriptorProto* const*)_upb_array_accessor(msg, UPB_SIZE(16, 32), len); }
+UPB_INLINE bool google_protobuf_ServiceDescriptorProto_has_options(const google_protobuf_ServiceDescriptorProto *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE const google_protobuf_ServiceOptions* google_protobuf_ServiceDescriptorProto_options(const google_protobuf_ServiceDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_ServiceOptions*, UPB_SIZE(12, 24)); }
+
+UPB_INLINE void google_protobuf_ServiceDescriptorProto_set_name(google_protobuf_ServiceDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)) = value;
+}
+UPB_INLINE google_protobuf_MethodDescriptorProto** google_protobuf_ServiceDescriptorProto_mutable_method(google_protobuf_ServiceDescriptorProto *msg, size_t *len) {
+  return (google_protobuf_MethodDescriptorProto**)_upb_array_mutable_accessor(msg, UPB_SIZE(16, 32), len);
+}
+UPB_INLINE google_protobuf_MethodDescriptorProto** google_protobuf_ServiceDescriptorProto_resize_method(google_protobuf_ServiceDescriptorProto *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_MethodDescriptorProto**)_upb_array_resize_accessor(msg, UPB_SIZE(16, 32), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_MethodDescriptorProto* google_protobuf_ServiceDescriptorProto_add_method(google_protobuf_ServiceDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_MethodDescriptorProto* sub = (struct google_protobuf_MethodDescriptorProto*)upb_msg_new(&google_protobuf_MethodDescriptorProto_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(16, 32), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE void google_protobuf_ServiceDescriptorProto_set_options(google_protobuf_ServiceDescriptorProto *msg, google_protobuf_ServiceOptions* value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, google_protobuf_ServiceOptions*, UPB_SIZE(12, 24)) = value;
+}
+UPB_INLINE struct google_protobuf_ServiceOptions* google_protobuf_ServiceDescriptorProto_mutable_options(google_protobuf_ServiceDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_ServiceOptions* sub = (struct google_protobuf_ServiceOptions*)google_protobuf_ServiceDescriptorProto_options(msg);
+  if (sub == NULL) {
+    sub = (struct google_protobuf_ServiceOptions*)upb_msg_new(&google_protobuf_ServiceOptions_msginit, arena);
+    if (!sub) return NULL;
+    google_protobuf_ServiceDescriptorProto_set_options(msg, sub);
+  }
+  return sub;
+}
+
+
+/* google.protobuf.MethodDescriptorProto */
+
+UPB_INLINE google_protobuf_MethodDescriptorProto *google_protobuf_MethodDescriptorProto_new(upb_arena *arena) {
+  return (google_protobuf_MethodDescriptorProto *)upb_msg_new(&google_protobuf_MethodDescriptorProto_msginit, arena);
+}
+UPB_INLINE google_protobuf_MethodDescriptorProto *google_protobuf_MethodDescriptorProto_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_MethodDescriptorProto *ret = google_protobuf_MethodDescriptorProto_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_MethodDescriptorProto_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_MethodDescriptorProto_serialize(const google_protobuf_MethodDescriptorProto *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_MethodDescriptorProto_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_MethodDescriptorProto_has_name(const google_protobuf_MethodDescriptorProto *msg) { return _upb_has_field(msg, 3); }
+UPB_INLINE upb_strview google_protobuf_MethodDescriptorProto_name(const google_protobuf_MethodDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)); }
+UPB_INLINE bool google_protobuf_MethodDescriptorProto_has_input_type(const google_protobuf_MethodDescriptorProto *msg) { return _upb_has_field(msg, 4); }
+UPB_INLINE upb_strview google_protobuf_MethodDescriptorProto_input_type(const google_protobuf_MethodDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(12, 24)); }
+UPB_INLINE bool google_protobuf_MethodDescriptorProto_has_output_type(const google_protobuf_MethodDescriptorProto *msg) { return _upb_has_field(msg, 5); }
+UPB_INLINE upb_strview google_protobuf_MethodDescriptorProto_output_type(const google_protobuf_MethodDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(20, 40)); }
+UPB_INLINE bool google_protobuf_MethodDescriptorProto_has_options(const google_protobuf_MethodDescriptorProto *msg) { return _upb_has_field(msg, 6); }
+UPB_INLINE const google_protobuf_MethodOptions* google_protobuf_MethodDescriptorProto_options(const google_protobuf_MethodDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_MethodOptions*, UPB_SIZE(28, 56)); }
+UPB_INLINE bool google_protobuf_MethodDescriptorProto_has_client_streaming(const google_protobuf_MethodDescriptorProto *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE bool google_protobuf_MethodDescriptorProto_client_streaming(const google_protobuf_MethodDescriptorProto *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)); }
+UPB_INLINE bool google_protobuf_MethodDescriptorProto_has_server_streaming(const google_protobuf_MethodDescriptorProto *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE bool google_protobuf_MethodDescriptorProto_server_streaming(const google_protobuf_MethodDescriptorProto *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(2, 2)); }
+
+UPB_INLINE void google_protobuf_MethodDescriptorProto_set_name(google_protobuf_MethodDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 3);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)) = value;
+}
+UPB_INLINE void google_protobuf_MethodDescriptorProto_set_input_type(google_protobuf_MethodDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 4);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(12, 24)) = value;
+}
+UPB_INLINE void google_protobuf_MethodDescriptorProto_set_output_type(google_protobuf_MethodDescriptorProto *msg, upb_strview value) {
+  _upb_sethas(msg, 5);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(20, 40)) = value;
+}
+UPB_INLINE void google_protobuf_MethodDescriptorProto_set_options(google_protobuf_MethodDescriptorProto *msg, google_protobuf_MethodOptions* value) {
+  _upb_sethas(msg, 6);
+  UPB_FIELD_AT(msg, google_protobuf_MethodOptions*, UPB_SIZE(28, 56)) = value;
+}
+UPB_INLINE struct google_protobuf_MethodOptions* google_protobuf_MethodDescriptorProto_mutable_options(google_protobuf_MethodDescriptorProto *msg, upb_arena *arena) {
+  struct google_protobuf_MethodOptions* sub = (struct google_protobuf_MethodOptions*)google_protobuf_MethodDescriptorProto_options(msg);
+  if (sub == NULL) {
+    sub = (struct google_protobuf_MethodOptions*)upb_msg_new(&google_protobuf_MethodOptions_msginit, arena);
+    if (!sub) return NULL;
+    google_protobuf_MethodDescriptorProto_set_options(msg, sub);
+  }
+  return sub;
+}
+UPB_INLINE void google_protobuf_MethodDescriptorProto_set_client_streaming(google_protobuf_MethodDescriptorProto *msg, bool value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)) = value;
+}
+UPB_INLINE void google_protobuf_MethodDescriptorProto_set_server_streaming(google_protobuf_MethodDescriptorProto *msg, bool value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(2, 2)) = value;
+}
+
+
+/* google.protobuf.FileOptions */
+
+UPB_INLINE google_protobuf_FileOptions *google_protobuf_FileOptions_new(upb_arena *arena) {
+  return (google_protobuf_FileOptions *)upb_msg_new(&google_protobuf_FileOptions_msginit, arena);
+}
+UPB_INLINE google_protobuf_FileOptions *google_protobuf_FileOptions_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_FileOptions *ret = google_protobuf_FileOptions_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_FileOptions_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_FileOptions_serialize(const google_protobuf_FileOptions *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_FileOptions_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_FileOptions_has_java_package(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 11); }
+UPB_INLINE upb_strview google_protobuf_FileOptions_java_package(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(28, 32)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_java_outer_classname(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 12); }
+UPB_INLINE upb_strview google_protobuf_FileOptions_java_outer_classname(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(36, 48)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_optimize_for(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE google_protobuf_FileOptions_OptimizeMode google_protobuf_FileOptions_optimize_for(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, google_protobuf_FileOptions_OptimizeMode, UPB_SIZE(8, 8)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_java_multiple_files(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE bool google_protobuf_FileOptions_java_multiple_files(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(16, 16)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_go_package(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 13); }
+UPB_INLINE upb_strview google_protobuf_FileOptions_go_package(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(44, 64)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_cc_generic_services(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 3); }
+UPB_INLINE bool google_protobuf_FileOptions_cc_generic_services(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(17, 17)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_java_generic_services(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 4); }
+UPB_INLINE bool google_protobuf_FileOptions_java_generic_services(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(18, 18)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_py_generic_services(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 5); }
+UPB_INLINE bool google_protobuf_FileOptions_py_generic_services(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(19, 19)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_java_generate_equals_and_hash(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 6); }
+UPB_INLINE bool google_protobuf_FileOptions_java_generate_equals_and_hash(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(20, 20)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_deprecated(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 7); }
+UPB_INLINE bool google_protobuf_FileOptions_deprecated(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(21, 21)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_java_string_check_utf8(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 8); }
+UPB_INLINE bool google_protobuf_FileOptions_java_string_check_utf8(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(22, 22)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_cc_enable_arenas(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 9); }
+UPB_INLINE bool google_protobuf_FileOptions_cc_enable_arenas(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(23, 23)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_objc_class_prefix(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 14); }
+UPB_INLINE upb_strview google_protobuf_FileOptions_objc_class_prefix(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(52, 80)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_csharp_namespace(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 15); }
+UPB_INLINE upb_strview google_protobuf_FileOptions_csharp_namespace(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(60, 96)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_swift_prefix(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 16); }
+UPB_INLINE upb_strview google_protobuf_FileOptions_swift_prefix(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(68, 112)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_php_class_prefix(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 17); }
+UPB_INLINE upb_strview google_protobuf_FileOptions_php_class_prefix(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(76, 128)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_php_namespace(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 18); }
+UPB_INLINE upb_strview google_protobuf_FileOptions_php_namespace(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(84, 144)); }
+UPB_INLINE bool google_protobuf_FileOptions_has_php_generic_services(const google_protobuf_FileOptions *msg) { return _upb_has_field(msg, 10); }
+UPB_INLINE bool google_protobuf_FileOptions_php_generic_services(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(24, 24)); }
+UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_FileOptions_uninterpreted_option(const google_protobuf_FileOptions *msg, size_t *len) { return (const google_protobuf_UninterpretedOption* const*)_upb_array_accessor(msg, UPB_SIZE(92, 160), len); }
+
+UPB_INLINE void google_protobuf_FileOptions_set_java_package(google_protobuf_FileOptions *msg, upb_strview value) {
+  _upb_sethas(msg, 11);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(28, 32)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_java_outer_classname(google_protobuf_FileOptions *msg, upb_strview value) {
+  _upb_sethas(msg, 12);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(36, 48)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_optimize_for(google_protobuf_FileOptions *msg, google_protobuf_FileOptions_OptimizeMode value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, google_protobuf_FileOptions_OptimizeMode, UPB_SIZE(8, 8)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_java_multiple_files(google_protobuf_FileOptions *msg, bool value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(16, 16)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_go_package(google_protobuf_FileOptions *msg, upb_strview value) {
+  _upb_sethas(msg, 13);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(44, 64)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_cc_generic_services(google_protobuf_FileOptions *msg, bool value) {
+  _upb_sethas(msg, 3);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(17, 17)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_java_generic_services(google_protobuf_FileOptions *msg, bool value) {
+  _upb_sethas(msg, 4);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(18, 18)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_py_generic_services(google_protobuf_FileOptions *msg, bool value) {
+  _upb_sethas(msg, 5);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(19, 19)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_java_generate_equals_and_hash(google_protobuf_FileOptions *msg, bool value) {
+  _upb_sethas(msg, 6);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(20, 20)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_deprecated(google_protobuf_FileOptions *msg, bool value) {
+  _upb_sethas(msg, 7);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(21, 21)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_java_string_check_utf8(google_protobuf_FileOptions *msg, bool value) {
+  _upb_sethas(msg, 8);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(22, 22)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_cc_enable_arenas(google_protobuf_FileOptions *msg, bool value) {
+  _upb_sethas(msg, 9);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(23, 23)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_objc_class_prefix(google_protobuf_FileOptions *msg, upb_strview value) {
+  _upb_sethas(msg, 14);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(52, 80)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_csharp_namespace(google_protobuf_FileOptions *msg, upb_strview value) {
+  _upb_sethas(msg, 15);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(60, 96)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_swift_prefix(google_protobuf_FileOptions *msg, upb_strview value) {
+  _upb_sethas(msg, 16);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(68, 112)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_php_class_prefix(google_protobuf_FileOptions *msg, upb_strview value) {
+  _upb_sethas(msg, 17);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(76, 128)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_php_namespace(google_protobuf_FileOptions *msg, upb_strview value) {
+  _upb_sethas(msg, 18);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(84, 144)) = value;
+}
+UPB_INLINE void google_protobuf_FileOptions_set_php_generic_services(google_protobuf_FileOptions *msg, bool value) {
+  _upb_sethas(msg, 10);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(24, 24)) = value;
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_FileOptions_mutable_uninterpreted_option(google_protobuf_FileOptions *msg, size_t *len) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_mutable_accessor(msg, UPB_SIZE(92, 160), len);
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_FileOptions_resize_uninterpreted_option(google_protobuf_FileOptions *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_resize_accessor(msg, UPB_SIZE(92, 160), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_FileOptions_add_uninterpreted_option(google_protobuf_FileOptions *msg, upb_arena *arena) {
+  struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)upb_msg_new(&google_protobuf_UninterpretedOption_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(92, 160), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+
+
+/* google.protobuf.MessageOptions */
+
+UPB_INLINE google_protobuf_MessageOptions *google_protobuf_MessageOptions_new(upb_arena *arena) {
+  return (google_protobuf_MessageOptions *)upb_msg_new(&google_protobuf_MessageOptions_msginit, arena);
+}
+UPB_INLINE google_protobuf_MessageOptions *google_protobuf_MessageOptions_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_MessageOptions *ret = google_protobuf_MessageOptions_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_MessageOptions_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_MessageOptions_serialize(const google_protobuf_MessageOptions *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_MessageOptions_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_MessageOptions_has_message_set_wire_format(const google_protobuf_MessageOptions *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE bool google_protobuf_MessageOptions_message_set_wire_format(const google_protobuf_MessageOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)); }
+UPB_INLINE bool google_protobuf_MessageOptions_has_no_standard_descriptor_accessor(const google_protobuf_MessageOptions *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE bool google_protobuf_MessageOptions_no_standard_descriptor_accessor(const google_protobuf_MessageOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(2, 2)); }
+UPB_INLINE bool google_protobuf_MessageOptions_has_deprecated(const google_protobuf_MessageOptions *msg) { return _upb_has_field(msg, 3); }
+UPB_INLINE bool google_protobuf_MessageOptions_deprecated(const google_protobuf_MessageOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(3, 3)); }
+UPB_INLINE bool google_protobuf_MessageOptions_has_map_entry(const google_protobuf_MessageOptions *msg) { return _upb_has_field(msg, 4); }
+UPB_INLINE bool google_protobuf_MessageOptions_map_entry(const google_protobuf_MessageOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(4, 4)); }
+UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_MessageOptions_uninterpreted_option(const google_protobuf_MessageOptions *msg, size_t *len) { return (const google_protobuf_UninterpretedOption* const*)_upb_array_accessor(msg, UPB_SIZE(8, 8), len); }
+
+UPB_INLINE void google_protobuf_MessageOptions_set_message_set_wire_format(google_protobuf_MessageOptions *msg, bool value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)) = value;
+}
+UPB_INLINE void google_protobuf_MessageOptions_set_no_standard_descriptor_accessor(google_protobuf_MessageOptions *msg, bool value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(2, 2)) = value;
+}
+UPB_INLINE void google_protobuf_MessageOptions_set_deprecated(google_protobuf_MessageOptions *msg, bool value) {
+  _upb_sethas(msg, 3);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(3, 3)) = value;
+}
+UPB_INLINE void google_protobuf_MessageOptions_set_map_entry(google_protobuf_MessageOptions *msg, bool value) {
+  _upb_sethas(msg, 4);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(4, 4)) = value;
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_MessageOptions_mutable_uninterpreted_option(google_protobuf_MessageOptions *msg, size_t *len) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_mutable_accessor(msg, UPB_SIZE(8, 8), len);
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_MessageOptions_resize_uninterpreted_option(google_protobuf_MessageOptions *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_resize_accessor(msg, UPB_SIZE(8, 8), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_MessageOptions_add_uninterpreted_option(google_protobuf_MessageOptions *msg, upb_arena *arena) {
+  struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)upb_msg_new(&google_protobuf_UninterpretedOption_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(8, 8), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+
+
+/* google.protobuf.FieldOptions */
+
+UPB_INLINE google_protobuf_FieldOptions *google_protobuf_FieldOptions_new(upb_arena *arena) {
+  return (google_protobuf_FieldOptions *)upb_msg_new(&google_protobuf_FieldOptions_msginit, arena);
+}
+UPB_INLINE google_protobuf_FieldOptions *google_protobuf_FieldOptions_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_FieldOptions *ret = google_protobuf_FieldOptions_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_FieldOptions_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_FieldOptions_serialize(const google_protobuf_FieldOptions *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_FieldOptions_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_FieldOptions_has_ctype(const google_protobuf_FieldOptions *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE google_protobuf_FieldOptions_CType google_protobuf_FieldOptions_ctype(const google_protobuf_FieldOptions *msg) { return UPB_FIELD_AT(msg, google_protobuf_FieldOptions_CType, UPB_SIZE(8, 8)); }
+UPB_INLINE bool google_protobuf_FieldOptions_has_packed(const google_protobuf_FieldOptions *msg) { return _upb_has_field(msg, 3); }
+UPB_INLINE bool google_protobuf_FieldOptions_packed(const google_protobuf_FieldOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(24, 24)); }
+UPB_INLINE bool google_protobuf_FieldOptions_has_deprecated(const google_protobuf_FieldOptions *msg) { return _upb_has_field(msg, 4); }
+UPB_INLINE bool google_protobuf_FieldOptions_deprecated(const google_protobuf_FieldOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(25, 25)); }
+UPB_INLINE bool google_protobuf_FieldOptions_has_lazy(const google_protobuf_FieldOptions *msg) { return _upb_has_field(msg, 5); }
+UPB_INLINE bool google_protobuf_FieldOptions_lazy(const google_protobuf_FieldOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(26, 26)); }
+UPB_INLINE bool google_protobuf_FieldOptions_has_jstype(const google_protobuf_FieldOptions *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE google_protobuf_FieldOptions_JSType google_protobuf_FieldOptions_jstype(const google_protobuf_FieldOptions *msg) { return UPB_FIELD_AT(msg, google_protobuf_FieldOptions_JSType, UPB_SIZE(16, 16)); }
+UPB_INLINE bool google_protobuf_FieldOptions_has_weak(const google_protobuf_FieldOptions *msg) { return _upb_has_field(msg, 6); }
+UPB_INLINE bool google_protobuf_FieldOptions_weak(const google_protobuf_FieldOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(27, 27)); }
+UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_FieldOptions_uninterpreted_option(const google_protobuf_FieldOptions *msg, size_t *len) { return (const google_protobuf_UninterpretedOption* const*)_upb_array_accessor(msg, UPB_SIZE(28, 32), len); }
+
+UPB_INLINE void google_protobuf_FieldOptions_set_ctype(google_protobuf_FieldOptions *msg, google_protobuf_FieldOptions_CType value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, google_protobuf_FieldOptions_CType, UPB_SIZE(8, 8)) = value;
+}
+UPB_INLINE void google_protobuf_FieldOptions_set_packed(google_protobuf_FieldOptions *msg, bool value) {
+  _upb_sethas(msg, 3);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(24, 24)) = value;
+}
+UPB_INLINE void google_protobuf_FieldOptions_set_deprecated(google_protobuf_FieldOptions *msg, bool value) {
+  _upb_sethas(msg, 4);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(25, 25)) = value;
+}
+UPB_INLINE void google_protobuf_FieldOptions_set_lazy(google_protobuf_FieldOptions *msg, bool value) {
+  _upb_sethas(msg, 5);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(26, 26)) = value;
+}
+UPB_INLINE void google_protobuf_FieldOptions_set_jstype(google_protobuf_FieldOptions *msg, google_protobuf_FieldOptions_JSType value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, google_protobuf_FieldOptions_JSType, UPB_SIZE(16, 16)) = value;
+}
+UPB_INLINE void google_protobuf_FieldOptions_set_weak(google_protobuf_FieldOptions *msg, bool value) {
+  _upb_sethas(msg, 6);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(27, 27)) = value;
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_FieldOptions_mutable_uninterpreted_option(google_protobuf_FieldOptions *msg, size_t *len) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_mutable_accessor(msg, UPB_SIZE(28, 32), len);
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_FieldOptions_resize_uninterpreted_option(google_protobuf_FieldOptions *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_resize_accessor(msg, UPB_SIZE(28, 32), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_FieldOptions_add_uninterpreted_option(google_protobuf_FieldOptions *msg, upb_arena *arena) {
+  struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)upb_msg_new(&google_protobuf_UninterpretedOption_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(28, 32), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+
+
+/* google.protobuf.OneofOptions */
+
+UPB_INLINE google_protobuf_OneofOptions *google_protobuf_OneofOptions_new(upb_arena *arena) {
+  return (google_protobuf_OneofOptions *)upb_msg_new(&google_protobuf_OneofOptions_msginit, arena);
+}
+UPB_INLINE google_protobuf_OneofOptions *google_protobuf_OneofOptions_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_OneofOptions *ret = google_protobuf_OneofOptions_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_OneofOptions_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_OneofOptions_serialize(const google_protobuf_OneofOptions *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_OneofOptions_msginit, arena, len);
+}
+
+UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_OneofOptions_uninterpreted_option(const google_protobuf_OneofOptions *msg, size_t *len) { return (const google_protobuf_UninterpretedOption* const*)_upb_array_accessor(msg, UPB_SIZE(0, 0), len); }
+
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_OneofOptions_mutable_uninterpreted_option(google_protobuf_OneofOptions *msg, size_t *len) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_mutable_accessor(msg, UPB_SIZE(0, 0), len);
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_OneofOptions_resize_uninterpreted_option(google_protobuf_OneofOptions *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_resize_accessor(msg, UPB_SIZE(0, 0), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_OneofOptions_add_uninterpreted_option(google_protobuf_OneofOptions *msg, upb_arena *arena) {
+  struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)upb_msg_new(&google_protobuf_UninterpretedOption_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(0, 0), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+
+
+/* google.protobuf.EnumOptions */
+
+UPB_INLINE google_protobuf_EnumOptions *google_protobuf_EnumOptions_new(upb_arena *arena) {
+  return (google_protobuf_EnumOptions *)upb_msg_new(&google_protobuf_EnumOptions_msginit, arena);
+}
+UPB_INLINE google_protobuf_EnumOptions *google_protobuf_EnumOptions_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_EnumOptions *ret = google_protobuf_EnumOptions_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_EnumOptions_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_EnumOptions_serialize(const google_protobuf_EnumOptions *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_EnumOptions_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_EnumOptions_has_allow_alias(const google_protobuf_EnumOptions *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE bool google_protobuf_EnumOptions_allow_alias(const google_protobuf_EnumOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)); }
+UPB_INLINE bool google_protobuf_EnumOptions_has_deprecated(const google_protobuf_EnumOptions *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE bool google_protobuf_EnumOptions_deprecated(const google_protobuf_EnumOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(2, 2)); }
+UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_EnumOptions_uninterpreted_option(const google_protobuf_EnumOptions *msg, size_t *len) { return (const google_protobuf_UninterpretedOption* const*)_upb_array_accessor(msg, UPB_SIZE(4, 8), len); }
+
+UPB_INLINE void google_protobuf_EnumOptions_set_allow_alias(google_protobuf_EnumOptions *msg, bool value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)) = value;
+}
+UPB_INLINE void google_protobuf_EnumOptions_set_deprecated(google_protobuf_EnumOptions *msg, bool value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(2, 2)) = value;
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_EnumOptions_mutable_uninterpreted_option(google_protobuf_EnumOptions *msg, size_t *len) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_mutable_accessor(msg, UPB_SIZE(4, 8), len);
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_EnumOptions_resize_uninterpreted_option(google_protobuf_EnumOptions *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_resize_accessor(msg, UPB_SIZE(4, 8), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_EnumOptions_add_uninterpreted_option(google_protobuf_EnumOptions *msg, upb_arena *arena) {
+  struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)upb_msg_new(&google_protobuf_UninterpretedOption_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(4, 8), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+
+
+/* google.protobuf.EnumValueOptions */
+
+UPB_INLINE google_protobuf_EnumValueOptions *google_protobuf_EnumValueOptions_new(upb_arena *arena) {
+  return (google_protobuf_EnumValueOptions *)upb_msg_new(&google_protobuf_EnumValueOptions_msginit, arena);
+}
+UPB_INLINE google_protobuf_EnumValueOptions *google_protobuf_EnumValueOptions_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_EnumValueOptions *ret = google_protobuf_EnumValueOptions_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_EnumValueOptions_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_EnumValueOptions_serialize(const google_protobuf_EnumValueOptions *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_EnumValueOptions_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_EnumValueOptions_has_deprecated(const google_protobuf_EnumValueOptions *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE bool google_protobuf_EnumValueOptions_deprecated(const google_protobuf_EnumValueOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)); }
+UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_EnumValueOptions_uninterpreted_option(const google_protobuf_EnumValueOptions *msg, size_t *len) { return (const google_protobuf_UninterpretedOption* const*)_upb_array_accessor(msg, UPB_SIZE(4, 8), len); }
+
+UPB_INLINE void google_protobuf_EnumValueOptions_set_deprecated(google_protobuf_EnumValueOptions *msg, bool value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)) = value;
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_EnumValueOptions_mutable_uninterpreted_option(google_protobuf_EnumValueOptions *msg, size_t *len) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_mutable_accessor(msg, UPB_SIZE(4, 8), len);
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_EnumValueOptions_resize_uninterpreted_option(google_protobuf_EnumValueOptions *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_resize_accessor(msg, UPB_SIZE(4, 8), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_EnumValueOptions_add_uninterpreted_option(google_protobuf_EnumValueOptions *msg, upb_arena *arena) {
+  struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)upb_msg_new(&google_protobuf_UninterpretedOption_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(4, 8), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+
+
+/* google.protobuf.ServiceOptions */
+
+UPB_INLINE google_protobuf_ServiceOptions *google_protobuf_ServiceOptions_new(upb_arena *arena) {
+  return (google_protobuf_ServiceOptions *)upb_msg_new(&google_protobuf_ServiceOptions_msginit, arena);
+}
+UPB_INLINE google_protobuf_ServiceOptions *google_protobuf_ServiceOptions_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_ServiceOptions *ret = google_protobuf_ServiceOptions_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_ServiceOptions_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_ServiceOptions_serialize(const google_protobuf_ServiceOptions *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_ServiceOptions_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_ServiceOptions_has_deprecated(const google_protobuf_ServiceOptions *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE bool google_protobuf_ServiceOptions_deprecated(const google_protobuf_ServiceOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)); }
+UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_ServiceOptions_uninterpreted_option(const google_protobuf_ServiceOptions *msg, size_t *len) { return (const google_protobuf_UninterpretedOption* const*)_upb_array_accessor(msg, UPB_SIZE(4, 8), len); }
+
+UPB_INLINE void google_protobuf_ServiceOptions_set_deprecated(google_protobuf_ServiceOptions *msg, bool value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)) = value;
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_ServiceOptions_mutable_uninterpreted_option(google_protobuf_ServiceOptions *msg, size_t *len) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_mutable_accessor(msg, UPB_SIZE(4, 8), len);
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_ServiceOptions_resize_uninterpreted_option(google_protobuf_ServiceOptions *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_resize_accessor(msg, UPB_SIZE(4, 8), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_ServiceOptions_add_uninterpreted_option(google_protobuf_ServiceOptions *msg, upb_arena *arena) {
+  struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)upb_msg_new(&google_protobuf_UninterpretedOption_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(4, 8), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+
+
+/* google.protobuf.MethodOptions */
+
+UPB_INLINE google_protobuf_MethodOptions *google_protobuf_MethodOptions_new(upb_arena *arena) {
+  return (google_protobuf_MethodOptions *)upb_msg_new(&google_protobuf_MethodOptions_msginit, arena);
+}
+UPB_INLINE google_protobuf_MethodOptions *google_protobuf_MethodOptions_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_MethodOptions *ret = google_protobuf_MethodOptions_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_MethodOptions_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_MethodOptions_serialize(const google_protobuf_MethodOptions *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_MethodOptions_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_MethodOptions_has_deprecated(const google_protobuf_MethodOptions *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE bool google_protobuf_MethodOptions_deprecated(const google_protobuf_MethodOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(16, 16)); }
+UPB_INLINE bool google_protobuf_MethodOptions_has_idempotency_level(const google_protobuf_MethodOptions *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE google_protobuf_MethodOptions_IdempotencyLevel google_protobuf_MethodOptions_idempotency_level(const google_protobuf_MethodOptions *msg) { return UPB_FIELD_AT(msg, google_protobuf_MethodOptions_IdempotencyLevel, UPB_SIZE(8, 8)); }
+UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_MethodOptions_uninterpreted_option(const google_protobuf_MethodOptions *msg, size_t *len) { return (const google_protobuf_UninterpretedOption* const*)_upb_array_accessor(msg, UPB_SIZE(20, 24), len); }
+
+UPB_INLINE void google_protobuf_MethodOptions_set_deprecated(google_protobuf_MethodOptions *msg, bool value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(16, 16)) = value;
+}
+UPB_INLINE void google_protobuf_MethodOptions_set_idempotency_level(google_protobuf_MethodOptions *msg, google_protobuf_MethodOptions_IdempotencyLevel value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, google_protobuf_MethodOptions_IdempotencyLevel, UPB_SIZE(8, 8)) = value;
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_MethodOptions_mutable_uninterpreted_option(google_protobuf_MethodOptions *msg, size_t *len) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_mutable_accessor(msg, UPB_SIZE(20, 24), len);
+}
+UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_MethodOptions_resize_uninterpreted_option(google_protobuf_MethodOptions *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_UninterpretedOption**)_upb_array_resize_accessor(msg, UPB_SIZE(20, 24), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_MethodOptions_add_uninterpreted_option(google_protobuf_MethodOptions *msg, upb_arena *arena) {
+  struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)upb_msg_new(&google_protobuf_UninterpretedOption_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(20, 24), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+
+
+/* google.protobuf.UninterpretedOption */
+
+UPB_INLINE google_protobuf_UninterpretedOption *google_protobuf_UninterpretedOption_new(upb_arena *arena) {
+  return (google_protobuf_UninterpretedOption *)upb_msg_new(&google_protobuf_UninterpretedOption_msginit, arena);
+}
+UPB_INLINE google_protobuf_UninterpretedOption *google_protobuf_UninterpretedOption_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_UninterpretedOption *ret = google_protobuf_UninterpretedOption_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_UninterpretedOption_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_UninterpretedOption_serialize(const google_protobuf_UninterpretedOption *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_UninterpretedOption_msginit, arena, len);
+}
+
+UPB_INLINE const google_protobuf_UninterpretedOption_NamePart* const* google_protobuf_UninterpretedOption_name(const google_protobuf_UninterpretedOption *msg, size_t *len) { return (const google_protobuf_UninterpretedOption_NamePart* const*)_upb_array_accessor(msg, UPB_SIZE(56, 80), len); }
+UPB_INLINE bool google_protobuf_UninterpretedOption_has_identifier_value(const google_protobuf_UninterpretedOption *msg) { return _upb_has_field(msg, 4); }
+UPB_INLINE upb_strview google_protobuf_UninterpretedOption_identifier_value(const google_protobuf_UninterpretedOption *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(32, 32)); }
+UPB_INLINE bool google_protobuf_UninterpretedOption_has_positive_int_value(const google_protobuf_UninterpretedOption *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE uint64_t google_protobuf_UninterpretedOption_positive_int_value(const google_protobuf_UninterpretedOption *msg) { return UPB_FIELD_AT(msg, uint64_t, UPB_SIZE(8, 8)); }
+UPB_INLINE bool google_protobuf_UninterpretedOption_has_negative_int_value(const google_protobuf_UninterpretedOption *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE int64_t google_protobuf_UninterpretedOption_negative_int_value(const google_protobuf_UninterpretedOption *msg) { return UPB_FIELD_AT(msg, int64_t, UPB_SIZE(16, 16)); }
+UPB_INLINE bool google_protobuf_UninterpretedOption_has_double_value(const google_protobuf_UninterpretedOption *msg) { return _upb_has_field(msg, 3); }
+UPB_INLINE double google_protobuf_UninterpretedOption_double_value(const google_protobuf_UninterpretedOption *msg) { return UPB_FIELD_AT(msg, double, UPB_SIZE(24, 24)); }
+UPB_INLINE bool google_protobuf_UninterpretedOption_has_string_value(const google_protobuf_UninterpretedOption *msg) { return _upb_has_field(msg, 5); }
+UPB_INLINE upb_strview google_protobuf_UninterpretedOption_string_value(const google_protobuf_UninterpretedOption *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(40, 48)); }
+UPB_INLINE bool google_protobuf_UninterpretedOption_has_aggregate_value(const google_protobuf_UninterpretedOption *msg) { return _upb_has_field(msg, 6); }
+UPB_INLINE upb_strview google_protobuf_UninterpretedOption_aggregate_value(const google_protobuf_UninterpretedOption *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(48, 64)); }
+
+UPB_INLINE google_protobuf_UninterpretedOption_NamePart** google_protobuf_UninterpretedOption_mutable_name(google_protobuf_UninterpretedOption *msg, size_t *len) {
+  return (google_protobuf_UninterpretedOption_NamePart**)_upb_array_mutable_accessor(msg, UPB_SIZE(56, 80), len);
+}
+UPB_INLINE google_protobuf_UninterpretedOption_NamePart** google_protobuf_UninterpretedOption_resize_name(google_protobuf_UninterpretedOption *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_UninterpretedOption_NamePart**)_upb_array_resize_accessor(msg, UPB_SIZE(56, 80), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_UninterpretedOption_NamePart* google_protobuf_UninterpretedOption_add_name(google_protobuf_UninterpretedOption *msg, upb_arena *arena) {
+  struct google_protobuf_UninterpretedOption_NamePart* sub = (struct google_protobuf_UninterpretedOption_NamePart*)upb_msg_new(&google_protobuf_UninterpretedOption_NamePart_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(56, 80), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+UPB_INLINE void google_protobuf_UninterpretedOption_set_identifier_value(google_protobuf_UninterpretedOption *msg, upb_strview value) {
+  _upb_sethas(msg, 4);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(32, 32)) = value;
+}
+UPB_INLINE void google_protobuf_UninterpretedOption_set_positive_int_value(google_protobuf_UninterpretedOption *msg, uint64_t value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, uint64_t, UPB_SIZE(8, 8)) = value;
+}
+UPB_INLINE void google_protobuf_UninterpretedOption_set_negative_int_value(google_protobuf_UninterpretedOption *msg, int64_t value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, int64_t, UPB_SIZE(16, 16)) = value;
+}
+UPB_INLINE void google_protobuf_UninterpretedOption_set_double_value(google_protobuf_UninterpretedOption *msg, double value) {
+  _upb_sethas(msg, 3);
+  UPB_FIELD_AT(msg, double, UPB_SIZE(24, 24)) = value;
+}
+UPB_INLINE void google_protobuf_UninterpretedOption_set_string_value(google_protobuf_UninterpretedOption *msg, upb_strview value) {
+  _upb_sethas(msg, 5);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(40, 48)) = value;
+}
+UPB_INLINE void google_protobuf_UninterpretedOption_set_aggregate_value(google_protobuf_UninterpretedOption *msg, upb_strview value) {
+  _upb_sethas(msg, 6);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(48, 64)) = value;
+}
+
+
+/* google.protobuf.UninterpretedOption.NamePart */
+
+UPB_INLINE google_protobuf_UninterpretedOption_NamePart *google_protobuf_UninterpretedOption_NamePart_new(upb_arena *arena) {
+  return (google_protobuf_UninterpretedOption_NamePart *)upb_msg_new(&google_protobuf_UninterpretedOption_NamePart_msginit, arena);
+}
+UPB_INLINE google_protobuf_UninterpretedOption_NamePart *google_protobuf_UninterpretedOption_NamePart_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_UninterpretedOption_NamePart *ret = google_protobuf_UninterpretedOption_NamePart_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_UninterpretedOption_NamePart_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_UninterpretedOption_NamePart_serialize(const google_protobuf_UninterpretedOption_NamePart *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_UninterpretedOption_NamePart_msginit, arena, len);
+}
+
+UPB_INLINE bool google_protobuf_UninterpretedOption_NamePart_has_name_part(const google_protobuf_UninterpretedOption_NamePart *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE upb_strview google_protobuf_UninterpretedOption_NamePart_name_part(const google_protobuf_UninterpretedOption_NamePart *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)); }
+UPB_INLINE bool google_protobuf_UninterpretedOption_NamePart_has_is_extension(const google_protobuf_UninterpretedOption_NamePart *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE bool google_protobuf_UninterpretedOption_NamePart_is_extension(const google_protobuf_UninterpretedOption_NamePart *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)); }
+
+UPB_INLINE void google_protobuf_UninterpretedOption_NamePart_set_name_part(google_protobuf_UninterpretedOption_NamePart *msg, upb_strview value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)) = value;
+}
+UPB_INLINE void google_protobuf_UninterpretedOption_NamePart_set_is_extension(google_protobuf_UninterpretedOption_NamePart *msg, bool value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)) = value;
+}
+
+
+/* google.protobuf.SourceCodeInfo */
+
+UPB_INLINE google_protobuf_SourceCodeInfo *google_protobuf_SourceCodeInfo_new(upb_arena *arena) {
+  return (google_protobuf_SourceCodeInfo *)upb_msg_new(&google_protobuf_SourceCodeInfo_msginit, arena);
+}
+UPB_INLINE google_protobuf_SourceCodeInfo *google_protobuf_SourceCodeInfo_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_SourceCodeInfo *ret = google_protobuf_SourceCodeInfo_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_SourceCodeInfo_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_SourceCodeInfo_serialize(const google_protobuf_SourceCodeInfo *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_SourceCodeInfo_msginit, arena, len);
+}
+
+UPB_INLINE const google_protobuf_SourceCodeInfo_Location* const* google_protobuf_SourceCodeInfo_location(const google_protobuf_SourceCodeInfo *msg, size_t *len) { return (const google_protobuf_SourceCodeInfo_Location* const*)_upb_array_accessor(msg, UPB_SIZE(0, 0), len); }
+
+UPB_INLINE google_protobuf_SourceCodeInfo_Location** google_protobuf_SourceCodeInfo_mutable_location(google_protobuf_SourceCodeInfo *msg, size_t *len) {
+  return (google_protobuf_SourceCodeInfo_Location**)_upb_array_mutable_accessor(msg, UPB_SIZE(0, 0), len);
+}
+UPB_INLINE google_protobuf_SourceCodeInfo_Location** google_protobuf_SourceCodeInfo_resize_location(google_protobuf_SourceCodeInfo *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_SourceCodeInfo_Location**)_upb_array_resize_accessor(msg, UPB_SIZE(0, 0), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_SourceCodeInfo_Location* google_protobuf_SourceCodeInfo_add_location(google_protobuf_SourceCodeInfo *msg, upb_arena *arena) {
+  struct google_protobuf_SourceCodeInfo_Location* sub = (struct google_protobuf_SourceCodeInfo_Location*)upb_msg_new(&google_protobuf_SourceCodeInfo_Location_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(0, 0), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+
+
+/* google.protobuf.SourceCodeInfo.Location */
+
+UPB_INLINE google_protobuf_SourceCodeInfo_Location *google_protobuf_SourceCodeInfo_Location_new(upb_arena *arena) {
+  return (google_protobuf_SourceCodeInfo_Location *)upb_msg_new(&google_protobuf_SourceCodeInfo_Location_msginit, arena);
+}
+UPB_INLINE google_protobuf_SourceCodeInfo_Location *google_protobuf_SourceCodeInfo_Location_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_SourceCodeInfo_Location *ret = google_protobuf_SourceCodeInfo_Location_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_SourceCodeInfo_Location_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_SourceCodeInfo_Location_serialize(const google_protobuf_SourceCodeInfo_Location *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_SourceCodeInfo_Location_msginit, arena, len);
+}
+
+UPB_INLINE int32_t const* google_protobuf_SourceCodeInfo_Location_path(const google_protobuf_SourceCodeInfo_Location *msg, size_t *len) { return (int32_t const*)_upb_array_accessor(msg, UPB_SIZE(20, 40), len); }
+UPB_INLINE int32_t const* google_protobuf_SourceCodeInfo_Location_span(const google_protobuf_SourceCodeInfo_Location *msg, size_t *len) { return (int32_t const*)_upb_array_accessor(msg, UPB_SIZE(24, 48), len); }
+UPB_INLINE bool google_protobuf_SourceCodeInfo_Location_has_leading_comments(const google_protobuf_SourceCodeInfo_Location *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE upb_strview google_protobuf_SourceCodeInfo_Location_leading_comments(const google_protobuf_SourceCodeInfo_Location *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)); }
+UPB_INLINE bool google_protobuf_SourceCodeInfo_Location_has_trailing_comments(const google_protobuf_SourceCodeInfo_Location *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE upb_strview google_protobuf_SourceCodeInfo_Location_trailing_comments(const google_protobuf_SourceCodeInfo_Location *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(12, 24)); }
+UPB_INLINE upb_strview const* google_protobuf_SourceCodeInfo_Location_leading_detached_comments(const google_protobuf_SourceCodeInfo_Location *msg, size_t *len) { return (upb_strview const*)_upb_array_accessor(msg, UPB_SIZE(28, 56), len); }
+
+UPB_INLINE int32_t* google_protobuf_SourceCodeInfo_Location_mutable_path(google_protobuf_SourceCodeInfo_Location *msg, size_t *len) {
+  return (int32_t*)_upb_array_mutable_accessor(msg, UPB_SIZE(20, 40), len);
+}
+UPB_INLINE int32_t* google_protobuf_SourceCodeInfo_Location_resize_path(google_protobuf_SourceCodeInfo_Location *msg, size_t len, upb_arena *arena) {
+  return (int32_t*)_upb_array_resize_accessor(msg, UPB_SIZE(20, 40), len, UPB_SIZE(4, 4), UPB_TYPE_INT32, arena);
+}
+UPB_INLINE bool google_protobuf_SourceCodeInfo_Location_add_path(google_protobuf_SourceCodeInfo_Location *msg, int32_t val, upb_arena *arena) {
+  return _upb_array_append_accessor(
+      msg, UPB_SIZE(20, 40), UPB_SIZE(4, 4), UPB_TYPE_INT32, &val, arena);
+}
+UPB_INLINE int32_t* google_protobuf_SourceCodeInfo_Location_mutable_span(google_protobuf_SourceCodeInfo_Location *msg, size_t *len) {
+  return (int32_t*)_upb_array_mutable_accessor(msg, UPB_SIZE(24, 48), len);
+}
+UPB_INLINE int32_t* google_protobuf_SourceCodeInfo_Location_resize_span(google_protobuf_SourceCodeInfo_Location *msg, size_t len, upb_arena *arena) {
+  return (int32_t*)_upb_array_resize_accessor(msg, UPB_SIZE(24, 48), len, UPB_SIZE(4, 4), UPB_TYPE_INT32, arena);
+}
+UPB_INLINE bool google_protobuf_SourceCodeInfo_Location_add_span(google_protobuf_SourceCodeInfo_Location *msg, int32_t val, upb_arena *arena) {
+  return _upb_array_append_accessor(
+      msg, UPB_SIZE(24, 48), UPB_SIZE(4, 4), UPB_TYPE_INT32, &val, arena);
+}
+UPB_INLINE void google_protobuf_SourceCodeInfo_Location_set_leading_comments(google_protobuf_SourceCodeInfo_Location *msg, upb_strview value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(4, 8)) = value;
+}
+UPB_INLINE void google_protobuf_SourceCodeInfo_Location_set_trailing_comments(google_protobuf_SourceCodeInfo_Location *msg, upb_strview value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(12, 24)) = value;
+}
+UPB_INLINE upb_strview* google_protobuf_SourceCodeInfo_Location_mutable_leading_detached_comments(google_protobuf_SourceCodeInfo_Location *msg, size_t *len) {
+  return (upb_strview*)_upb_array_mutable_accessor(msg, UPB_SIZE(28, 56), len);
+}
+UPB_INLINE upb_strview* google_protobuf_SourceCodeInfo_Location_resize_leading_detached_comments(google_protobuf_SourceCodeInfo_Location *msg, size_t len, upb_arena *arena) {
+  return (upb_strview*)_upb_array_resize_accessor(msg, UPB_SIZE(28, 56), len, UPB_SIZE(8, 16), UPB_TYPE_STRING, arena);
+}
+UPB_INLINE bool google_protobuf_SourceCodeInfo_Location_add_leading_detached_comments(google_protobuf_SourceCodeInfo_Location *msg, upb_strview val, upb_arena *arena) {
+  return _upb_array_append_accessor(
+      msg, UPB_SIZE(28, 56), UPB_SIZE(8, 16), UPB_TYPE_STRING, &val, arena);
+}
+
+
+/* google.protobuf.GeneratedCodeInfo */
+
+UPB_INLINE google_protobuf_GeneratedCodeInfo *google_protobuf_GeneratedCodeInfo_new(upb_arena *arena) {
+  return (google_protobuf_GeneratedCodeInfo *)upb_msg_new(&google_protobuf_GeneratedCodeInfo_msginit, arena);
+}
+UPB_INLINE google_protobuf_GeneratedCodeInfo *google_protobuf_GeneratedCodeInfo_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_GeneratedCodeInfo *ret = google_protobuf_GeneratedCodeInfo_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_GeneratedCodeInfo_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_GeneratedCodeInfo_serialize(const google_protobuf_GeneratedCodeInfo *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_GeneratedCodeInfo_msginit, arena, len);
+}
+
+UPB_INLINE const google_protobuf_GeneratedCodeInfo_Annotation* const* google_protobuf_GeneratedCodeInfo_annotation(const google_protobuf_GeneratedCodeInfo *msg, size_t *len) { return (const google_protobuf_GeneratedCodeInfo_Annotation* const*)_upb_array_accessor(msg, UPB_SIZE(0, 0), len); }
+
+UPB_INLINE google_protobuf_GeneratedCodeInfo_Annotation** google_protobuf_GeneratedCodeInfo_mutable_annotation(google_protobuf_GeneratedCodeInfo *msg, size_t *len) {
+  return (google_protobuf_GeneratedCodeInfo_Annotation**)_upb_array_mutable_accessor(msg, UPB_SIZE(0, 0), len);
+}
+UPB_INLINE google_protobuf_GeneratedCodeInfo_Annotation** google_protobuf_GeneratedCodeInfo_resize_annotation(google_protobuf_GeneratedCodeInfo *msg, size_t len, upb_arena *arena) {
+  return (google_protobuf_GeneratedCodeInfo_Annotation**)_upb_array_resize_accessor(msg, UPB_SIZE(0, 0), len, UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, arena);
+}
+UPB_INLINE struct google_protobuf_GeneratedCodeInfo_Annotation* google_protobuf_GeneratedCodeInfo_add_annotation(google_protobuf_GeneratedCodeInfo *msg, upb_arena *arena) {
+  struct google_protobuf_GeneratedCodeInfo_Annotation* sub = (struct google_protobuf_GeneratedCodeInfo_Annotation*)upb_msg_new(&google_protobuf_GeneratedCodeInfo_Annotation_msginit, arena);
+  bool ok = _upb_array_append_accessor(
+      msg, UPB_SIZE(0, 0), UPB_SIZE(4, 8), UPB_TYPE_MESSAGE, &sub, arena);
+  if (!ok) return NULL;
+  return sub;
+}
+
+
+/* google.protobuf.GeneratedCodeInfo.Annotation */
+
+UPB_INLINE google_protobuf_GeneratedCodeInfo_Annotation *google_protobuf_GeneratedCodeInfo_Annotation_new(upb_arena *arena) {
+  return (google_protobuf_GeneratedCodeInfo_Annotation *)upb_msg_new(&google_protobuf_GeneratedCodeInfo_Annotation_msginit, arena);
+}
+UPB_INLINE google_protobuf_GeneratedCodeInfo_Annotation *google_protobuf_GeneratedCodeInfo_Annotation_parsenew(upb_strview buf, upb_arena *arena) {
+  google_protobuf_GeneratedCodeInfo_Annotation *ret = google_protobuf_GeneratedCodeInfo_Annotation_new(arena);
+  return (ret && upb_decode(buf, ret, &google_protobuf_GeneratedCodeInfo_Annotation_msginit)) ? ret : NULL;
+}
+UPB_INLINE char *google_protobuf_GeneratedCodeInfo_Annotation_serialize(const google_protobuf_GeneratedCodeInfo_Annotation *msg, upb_arena *arena, size_t *len) {
+  return upb_encode(msg, &google_protobuf_GeneratedCodeInfo_Annotation_msginit, arena, len);
+}
+
+UPB_INLINE int32_t const* google_protobuf_GeneratedCodeInfo_Annotation_path(const google_protobuf_GeneratedCodeInfo_Annotation *msg, size_t *len) { return (int32_t const*)_upb_array_accessor(msg, UPB_SIZE(20, 32), len); }
+UPB_INLINE bool google_protobuf_GeneratedCodeInfo_Annotation_has_source_file(const google_protobuf_GeneratedCodeInfo_Annotation *msg) { return _upb_has_field(msg, 3); }
+UPB_INLINE upb_strview google_protobuf_GeneratedCodeInfo_Annotation_source_file(const google_protobuf_GeneratedCodeInfo_Annotation *msg) { return UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(12, 16)); }
+UPB_INLINE bool google_protobuf_GeneratedCodeInfo_Annotation_has_begin(const google_protobuf_GeneratedCodeInfo_Annotation *msg) { return _upb_has_field(msg, 1); }
+UPB_INLINE int32_t google_protobuf_GeneratedCodeInfo_Annotation_begin(const google_protobuf_GeneratedCodeInfo_Annotation *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)); }
+UPB_INLINE bool google_protobuf_GeneratedCodeInfo_Annotation_has_end(const google_protobuf_GeneratedCodeInfo_Annotation *msg) { return _upb_has_field(msg, 2); }
+UPB_INLINE int32_t google_protobuf_GeneratedCodeInfo_Annotation_end(const google_protobuf_GeneratedCodeInfo_Annotation *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)); }
+
+UPB_INLINE int32_t* google_protobuf_GeneratedCodeInfo_Annotation_mutable_path(google_protobuf_GeneratedCodeInfo_Annotation *msg, size_t *len) {
+  return (int32_t*)_upb_array_mutable_accessor(msg, UPB_SIZE(20, 32), len);
+}
+UPB_INLINE int32_t* google_protobuf_GeneratedCodeInfo_Annotation_resize_path(google_protobuf_GeneratedCodeInfo_Annotation *msg, size_t len, upb_arena *arena) {
+  return (int32_t*)_upb_array_resize_accessor(msg, UPB_SIZE(20, 32), len, UPB_SIZE(4, 4), UPB_TYPE_INT32, arena);
+}
+UPB_INLINE bool google_protobuf_GeneratedCodeInfo_Annotation_add_path(google_protobuf_GeneratedCodeInfo_Annotation *msg, int32_t val, upb_arena *arena) {
+  return _upb_array_append_accessor(
+      msg, UPB_SIZE(20, 32), UPB_SIZE(4, 4), UPB_TYPE_INT32, &val, arena);
+}
+UPB_INLINE void google_protobuf_GeneratedCodeInfo_Annotation_set_source_file(google_protobuf_GeneratedCodeInfo_Annotation *msg, upb_strview value) {
+  _upb_sethas(msg, 3);
+  UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(12, 16)) = value;
+}
+UPB_INLINE void google_protobuf_GeneratedCodeInfo_Annotation_set_begin(google_protobuf_GeneratedCodeInfo_Annotation *msg, int32_t value) {
+  _upb_sethas(msg, 1);
+  UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)) = value;
+}
+UPB_INLINE void google_protobuf_GeneratedCodeInfo_Annotation_set_end(google_protobuf_GeneratedCodeInfo_Annotation *msg, int32_t value) {
+  _upb_sethas(msg, 2);
+  UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)) = value;
+}
+
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+
+#endif  /* GOOGLE_PROTOBUF_DESCRIPTOR_PROTO_UPB_H_ */
+/*
+** Defs are upb's internal representation of the constructs that can appear
+** in a .proto file:
+**
+** - upb::MessageDefPtr (upb_msgdef): describes a "message" construct.
+** - upb::FieldDefPtr (upb_fielddef): describes a message field.
+** - upb::FileDefPtr (upb_filedef): describes a .proto file and its defs.
+** - upb::EnumDefPtr (upb_enumdef): describes an enum.
+** - upb::OneofDefPtr (upb_oneofdef): describes a oneof.
+**
+** TODO: definitions of services.
+**
+** This is a mixed C/C++ interface that offers a full API to both languages.
+** See the top-level README for more information.
+*/
+
+#ifndef UPB_DEF_H_
+#define UPB_DEF_H_
+
+/*
+** upb_table
+**
+** This header is INTERNAL-ONLY!  Its interfaces are not public or stable!
+** This file defines very fast int->upb_value (inttable) and string->upb_value
+** (strtable) hash tables.
+**
+** The table uses chained scatter with Brent's variation (inspired by the Lua
+** implementation of hash tables).  The hash function for strings is Austin
+** Appleby's "MurmurHash."
+**
+** The inttable uses uintptr_t as its key, which guarantees it can be used to
+** store pointers or integers of at least 32 bits (upb isn't really useful on
+** systems where sizeof(void*) < 4).
+**
+** The table must be homogenous (all values of the same type).  In debug
+** mode, we check this on insert and lookup.
+*/
+
+#ifndef UPB_TABLE_H_
+#define UPB_TABLE_H_
+
+#include <stdint.h>
+#include <string.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -976,21 +2725,6 @@
  * initializing a non-first union member. */
 typedef uintptr_t upb_tabkey;
 
-#define UPB_TABKEY_NUM(n) n
-#define UPB_TABKEY_NONE 0
-/* The preprocessor isn't quite powerful enough to turn the compile-time string
- * length into a byte-wise string representation, so code generation needs to
- * help it along.
- *
- * "len1" is the low byte and len4 is the high byte. */
-#ifdef UPB_BIG_ENDIAN
-#define UPB_TABKEY_STR(len1, len2, len3, len4, strval) \
-    (uintptr_t)(len4 len3 len2 len1 strval)
-#else
-#define UPB_TABKEY_STR(len1, len2, len3, len4, strval) \
-    (uintptr_t)(len1 len2 len3 len4 strval)
-#endif
-
 UPB_INLINE char *upb_tabstr(upb_tabkey key, uint32_t *len) {
   char* mem = (char*)key;
   if (len) memcpy(len, mem, sizeof(*len));
@@ -1000,69 +2734,11 @@
 
 /* upb_tabval *****************************************************************/
 
-#ifdef __cplusplus
-
-/* Status initialization not supported.
- *
- * This separate definition is necessary because in C++, UINTPTR_MAX isn't
- * reliably available. */
 typedef struct {
   uint64_t val;
 } upb_tabval;
 
-#else
-
-/* C -- supports static initialization, but to support static initialization of
- * both integers and points for both 32 and 64 bit targets, it takes a little
- * bit of doing. */
-
-#if UINTPTR_MAX == 0xffffffffffffffffULL
-#define UPB_PTR_IS_64BITS
-#elif UINTPTR_MAX != 0xffffffff
-#error Could not determine how many bits pointers are.
-#endif
-
-typedef union {
-  /* For static initialization.
-   *
-   * Unfortunately this ugliness is necessary -- it is the only way that we can,
-   * with -std=c89 -pedantic, statically initialize this to either a pointer or
-   * an integer on 32-bit platforms. */
-  struct {
-#ifdef UPB_PTR_IS_64BITS
-    uintptr_t val;
-#else
-    uintptr_t val1;
-    uintptr_t val2;
-#endif
-  } staticinit;
-
-  /* The normal accessor that we use for everything at runtime. */
-  uint64_t val;
-} upb_tabval;
-
-#ifdef UPB_PTR_IS_64BITS
-#define UPB_TABVALUE_INT_INIT(v) {{v}}
-#define UPB_TABVALUE_EMPTY_INIT  {{-1}}
-#else
-
-/* 32-bit pointers */
-
-#ifdef UPB_BIG_ENDIAN
-#define UPB_TABVALUE_INT_INIT(v) {{0, v}}
-#define UPB_TABVALUE_EMPTY_INIT  {{-1, -1}}
-#else
-#define UPB_TABVALUE_INT_INIT(v) {{v, 0}}
-#define UPB_TABVALUE_EMPTY_INIT  {{-1, -1}}
-#endif
-
-#endif
-
-#define UPB_TABVALUE_PTR_INIT(v) UPB_TABVALUE_INT_INIT((uintptr_t)v)
-
-#undef UPB_PTR_IS_64BITS
-
-#endif  /* __cplusplus */
+#define UPB_TABVALUE_EMPTY_INIT  {-1}
 
 
 /* upb_table ******************************************************************/
@@ -1104,31 +2780,10 @@
 #endif
 } upb_table;
 
-#ifdef NDEBUG
-#  define UPB_TABLE_INIT(count, mask, ctype, size_lg2, entries) \
-     {count, mask, ctype, size_lg2, entries}
-#else
-#  ifdef UPB_DEBUG_REFS
-/* At the moment the only mutable tables we statically initialize are debug
- * ref tables. */
-#    define UPB_TABLE_INIT(count, mask, ctype, size_lg2, entries) \
-       {count, mask, ctype, size_lg2, entries, &upb_alloc_debugrefs}
-#  else
-#    define UPB_TABLE_INIT(count, mask, ctype, size_lg2, entries) \
-       {count, mask, ctype, size_lg2, entries, NULL}
-#  endif
-#endif
-
 typedef struct {
   upb_table t;
 } upb_strtable;
 
-#define UPB_STRTABLE_INIT(count, mask, ctype, size_lg2, entries) \
-  {UPB_TABLE_INIT(count, mask, ctype, size_lg2, entries)}
-
-#define UPB_EMPTY_STRTABLE_INIT(ctype)                           \
-  UPB_STRTABLE_INIT(0, 0, ctype, 0, NULL)
-
 typedef struct {
   upb_table t;              /* For entries that don't fit in the array part. */
   const upb_tabval *array;  /* Array part of the table. See const note above. */
@@ -1416,585 +3071,34 @@
 
 #endif  /* UPB_TABLE_H_ */
 
-/* Reference tracking will check ref()/unref() operations to make sure the
- * ref ownership is correct.  Where possible it will also make tools like
- * Valgrind attribute ref leaks to the code that took the leaked ref, not
- * the code that originally created the object.
- *
- * Enabling this requires the application to define upb_lock()/upb_unlock()
- * functions that acquire/release a global mutex (or #define UPB_THREAD_UNSAFE).
- * For this reason we don't enable it by default, even in debug builds.
- */
-
-/* #define UPB_DEBUG_REFS */
-
-#ifdef __cplusplus
-namespace upb {
-class RefCounted;
-template <class T> class reffed_ptr;
-}
-#endif
-
-UPB_DECLARE_TYPE(upb::RefCounted, upb_refcounted)
-
-struct upb_refcounted_vtbl;
-
-#ifdef __cplusplus
-
-class upb::RefCounted {
- public:
-  /* Returns true if the given object is frozen. */
-  bool IsFrozen() const;
-
-  /* Increases the ref count, the new ref is owned by "owner" which must not
-   * already own a ref (and should not itself be a refcounted object if the ref
-   * could possibly be circular; see below).
-   * Thread-safe iff "this" is frozen. */
-  void Ref(const void *owner) const;
-
-  /* Release a ref that was acquired from upb_refcounted_ref() and collects any
-   * objects it can. */
-  void Unref(const void *owner) const;
-
-  /* Moves an existing ref from "from" to "to", without changing the overall
-   * ref count.  DonateRef(foo, NULL, owner) is the same as Ref(foo, owner),
-   * but "to" may not be NULL. */
-  void DonateRef(const void *from, const void *to) const;
-
-  /* Verifies that a ref to the given object is currently held by the given
-   * owner.  Only effective in UPB_DEBUG_REFS builds. */
-  void CheckRef(const void *owner) const;
-
- private:
-  UPB_DISALLOW_POD_OPS(RefCounted, upb::RefCounted)
-#else
-struct upb_refcounted {
-#endif
-  /* TODO(haberman): move the actual structure definition to structdefs.int.h.
-   * The only reason they are here is because inline functions need to see the
-   * definition of upb_handlers, which needs to see this definition.  But we
-   * can change the upb_handlers inline functions to deal in raw offsets
-   * instead.
-   */
-
-  /* A single reference count shared by all objects in the group. */
-  uint32_t *group;
-
-  /* A singly-linked list of all objects in the group. */
-  upb_refcounted *next;
-
-  /* Table of function pointers for this type. */
-  const struct upb_refcounted_vtbl *vtbl;
-
-  /* Maintained only when mutable, this tracks the number of refs (but not
-   * ref2's) to this object.  *group should be the sum of all individual_count
-   * in the group. */
-  uint32_t individual_count;
-
-  bool is_frozen;
-
-#ifdef UPB_DEBUG_REFS
-  upb_inttable *refs;  /* Maps owner -> trackedref for incoming refs. */
-  upb_inttable *ref2s; /* Set of targets for outgoing ref2s. */
-#endif
-};
-
-#ifdef UPB_DEBUG_REFS
-extern upb_alloc upb_alloc_debugrefs;
-#define UPB_REFCOUNT_INIT(vtbl, refs, ref2s) \
-    {&static_refcount, NULL, vtbl, 0, true, refs, ref2s}
-#else
-#define UPB_REFCOUNT_INIT(vtbl, refs, ref2s) \
-    {&static_refcount, NULL, vtbl, 0, true}
-#endif
-
-UPB_BEGIN_EXTERN_C
-
-/* It is better to use tracked refs when possible, for the extra debugging
- * capability.  But if this is not possible (because you don't have easy access
- * to a stable pointer value that is associated with the ref), you can pass
- * UPB_UNTRACKED_REF instead.  */
-extern const void *UPB_UNTRACKED_REF;
-
-/* Native C API. */
-bool upb_refcounted_isfrozen(const upb_refcounted *r);
-void upb_refcounted_ref(const upb_refcounted *r, const void *owner);
-void upb_refcounted_unref(const upb_refcounted *r, const void *owner);
-void upb_refcounted_donateref(
-    const upb_refcounted *r, const void *from, const void *to);
-void upb_refcounted_checkref(const upb_refcounted *r, const void *owner);
-
-#define UPB_REFCOUNTED_CMETHODS(type, upcastfunc) \
-  UPB_INLINE bool type ## _isfrozen(const type *v) { \
-    return upb_refcounted_isfrozen(upcastfunc(v)); \
-  } \
-  UPB_INLINE void type ## _ref(const type *v, const void *owner) { \
-    upb_refcounted_ref(upcastfunc(v), owner); \
-  } \
-  UPB_INLINE void type ## _unref(const type *v, const void *owner) { \
-    upb_refcounted_unref(upcastfunc(v), owner); \
-  } \
-  UPB_INLINE void type ## _donateref(const type *v, const void *from, const void *to) { \
-    upb_refcounted_donateref(upcastfunc(v), from, to); \
-  } \
-  UPB_INLINE void type ## _checkref(const type *v, const void *owner) { \
-    upb_refcounted_checkref(upcastfunc(v), owner); \
-  }
-
-#define UPB_REFCOUNTED_CPPMETHODS \
-  bool IsFrozen() const { \
-    return upb::upcast_to<const upb::RefCounted>(this)->IsFrozen(); \
-  } \
-  void Ref(const void *owner) const { \
-    return upb::upcast_to<const upb::RefCounted>(this)->Ref(owner); \
-  } \
-  void Unref(const void *owner) const { \
-    return upb::upcast_to<const upb::RefCounted>(this)->Unref(owner); \
-  } \
-  void DonateRef(const void *from, const void *to) const { \
-    return upb::upcast_to<const upb::RefCounted>(this)->DonateRef(from, to); \
-  } \
-  void CheckRef(const void *owner) const { \
-    return upb::upcast_to<const upb::RefCounted>(this)->CheckRef(owner); \
-  }
-
-/* Internal-to-upb Interface **************************************************/
-
-typedef void upb_refcounted_visit(const upb_refcounted *r,
-                                  const upb_refcounted *subobj,
-                                  void *closure);
-
-struct upb_refcounted_vtbl {
-  /* Must visit all subobjects that are currently ref'd via upb_refcounted_ref2.
-   * Must be longjmp()-safe. */
-  void (*visit)(const upb_refcounted *r, upb_refcounted_visit *visit, void *c);
-
-  /* Must free the object and release all references to other objects. */
-  void (*free)(upb_refcounted *r);
-};
-
-/* Initializes the refcounted with a single ref for the given owner.  Returns
- * false if memory could not be allocated. */
-bool upb_refcounted_init(upb_refcounted *r,
-                         const struct upb_refcounted_vtbl *vtbl,
-                         const void *owner);
-
-/* Adds a ref from one refcounted object to another ("from" must not already
- * own a ref).  These refs may be circular; cycles will be collected correctly
- * (if conservatively).  These refs do not need to be freed in from's free()
- * function. */
-void upb_refcounted_ref2(const upb_refcounted *r, upb_refcounted *from);
-
-/* Removes a ref that was acquired from upb_refcounted_ref2(), and collects any
- * object it can.  This is only necessary when "from" no longer points to "r",
- * and not from from's "free" function. */
-void upb_refcounted_unref2(const upb_refcounted *r, upb_refcounted *from);
-
-#define upb_ref2(r, from) \
-    upb_refcounted_ref2((const upb_refcounted*)r, (upb_refcounted*)from)
-#define upb_unref2(r, from) \
-    upb_refcounted_unref2((const upb_refcounted*)r, (upb_refcounted*)from)
-
-/* Freezes all mutable object reachable by ref2() refs from the given roots.
- * This will split refcounting groups into precise SCC groups, so that
- * refcounting of frozen objects can be more aggressive.  If memory allocation
- * fails, or if more than 2**31 mutable objects are reachable from "roots", or
- * if the maximum depth of the graph exceeds "maxdepth", false is returned and
- * the objects are unchanged.
- *
- * After this operation succeeds, the objects are frozen/const, and may not be
- * used through non-const pointers.  In particular, they may not be passed as
- * the second parameter of upb_refcounted_{ref,unref}2().  On the upside, all
- * operations on frozen refcounteds are threadsafe, and objects will be freed
- * at the precise moment that they become unreachable.
- *
- * Caller must own refs on each object in the "roots" list. */
-bool upb_refcounted_freeze(upb_refcounted *const*roots, int n, upb_status *s,
-                           int maxdepth);
-
-/* Shared by all compiled-in refcounted objects. */
-extern uint32_t static_refcount;
-
-UPB_END_EXTERN_C
-
-#ifdef __cplusplus
-/* C++ Wrappers. */
-namespace upb {
-inline bool RefCounted::IsFrozen() const {
-  return upb_refcounted_isfrozen(this);
-}
-inline void RefCounted::Ref(const void *owner) const {
-  upb_refcounted_ref(this, owner);
-}
-inline void RefCounted::Unref(const void *owner) const {
-  upb_refcounted_unref(this, owner);
-}
-inline void RefCounted::DonateRef(const void *from, const void *to) const {
-  upb_refcounted_donateref(this, from, to);
-}
-inline void RefCounted::CheckRef(const void *owner) const {
-  upb_refcounted_checkref(this, owner);
-}
-}  /* namespace upb */
-#endif
-
-
-/* upb::reffed_ptr ************************************************************/
-
-#ifdef __cplusplus
-
-#include <algorithm>  /* For std::swap(). */
-
-/* Provides RAII semantics for upb refcounted objects.  Each reffed_ptr owns a
- * ref on whatever object it points to (if any). */
-template <class T> class upb::reffed_ptr {
- public:
-  reffed_ptr() : ptr_(NULL) {}
-
-  /* If ref_donor is NULL, takes a new ref, otherwise adopts from ref_donor. */
-  template <class U>
-  reffed_ptr(U* val, const void* ref_donor = NULL)
-      : ptr_(upb::upcast(val)) {
-    if (ref_donor) {
-      UPB_ASSERT(ptr_);
-      ptr_->DonateRef(ref_donor, this);
-    } else if (ptr_) {
-      ptr_->Ref(this);
-    }
-  }
-
-  template <class U>
-  reffed_ptr(const reffed_ptr<U>& other)
-      : ptr_(upb::upcast(other.get())) {
-    if (ptr_) ptr_->Ref(this);
-  }
-
-  reffed_ptr(const reffed_ptr& other)
-      : ptr_(upb::upcast(other.get())) {
-    if (ptr_) ptr_->Ref(this);
-  }
-
-  ~reffed_ptr() { if (ptr_) ptr_->Unref(this); }
-
-  template <class U>
-  reffed_ptr& operator=(const reffed_ptr<U>& other) {
-    reset(other.get());
-    return *this;
-  }
-
-  reffed_ptr& operator=(const reffed_ptr& other) {
-    reset(other.get());
-    return *this;
-  }
-
-  /* TODO(haberman): add C++11 move construction/assignment for greater
-   * efficiency. */
-
-  void swap(reffed_ptr& other) {
-    if (ptr_ == other.ptr_) {
-      return;
-    }
-
-    if (ptr_) ptr_->DonateRef(this, &other);
-    if (other.ptr_) other.ptr_->DonateRef(&other, this);
-    std::swap(ptr_, other.ptr_);
-  }
-
-  T& operator*() const {
-    UPB_ASSERT(ptr_);
-    return *ptr_;
-  }
-
-  T* operator->() const {
-    UPB_ASSERT(ptr_);
-    return ptr_;
-  }
-
-  T* get() const { return ptr_; }
-
-  /* If ref_donor is NULL, takes a new ref, otherwise adopts from ref_donor. */
-  template <class U>
-  void reset(U* ptr = NULL, const void* ref_donor = NULL) {
-    reffed_ptr(ptr, ref_donor).swap(*this);
-  }
-
-  template <class U>
-  reffed_ptr<U> down_cast() {
-    return reffed_ptr<U>(upb::down_cast<U*>(get()));
-  }
-
-  template <class U>
-  reffed_ptr<U> dyn_cast() {
-    return reffed_ptr<U>(upb::dyn_cast<U*>(get()));
-  }
-
-  /* Plain release() is unsafe; if we were the only owner, it would leak the
-   * object.  Instead we provide this: */
-  T* ReleaseTo(const void* new_owner) {
-    T* ret = NULL;
-    ptr_->DonateRef(this, new_owner);
-    std::swap(ret, ptr_);
-    return ret;
-  }
-
- private:
-  T* ptr_;
-};
-
-#endif  /* __cplusplus */
-
-#endif  /* UPB_REFCOUNT_H_ */
-
 #ifdef __cplusplus
 #include <cstring>
+#include <memory>
 #include <string>
 #include <vector>
 
 namespace upb {
-class Def;
-class EnumDef;
-class FieldDef;
-class FileDef;
-class MessageDef;
-class OneofDef;
+class EnumDefPtr;
+class FieldDefPtr;
+class FileDefPtr;
+class MessageDefPtr;
+class OneofDefPtr;
 class SymbolTable;
 }
 #endif
 
-UPB_DECLARE_DERIVED_TYPE(upb::Def, upb::RefCounted, upb_def, upb_refcounted)
-UPB_DECLARE_DERIVED_TYPE(upb::OneofDef, upb::RefCounted, upb_oneofdef,
-                         upb_refcounted)
-UPB_DECLARE_DERIVED_TYPE(upb::FileDef, upb::RefCounted, upb_filedef,
-                         upb_refcounted)
-UPB_DECLARE_TYPE(upb::SymbolTable, upb_symtab)
-
-
-/* The maximum message depth that the type graph can have.  This is a resource
- * limit for the C stack since we sometimes need to recursively traverse the
- * graph.  Cycles are ok; the traversal will stop when it detects a cycle, but
- * we must hit the cycle before the maximum depth is reached.
- *
- * If having a single static limit is too inflexible, we can add another variant
- * of Def::Freeze that allows specifying this as a parameter. */
-#define UPB_MAX_MESSAGE_DEPTH 64
-
-
-/* upb::Def: base class for top-level defs  ***********************************/
-
-/* All the different kind of defs that can be defined at the top-level and put
- * in a SymbolTable or appear in a FileDef::defs() list.  This excludes some
- * defs (like oneofs and files).  It only includes fields because they can be
- * defined as extensions. */
-typedef enum {
-  UPB_DEF_MSG,
-  UPB_DEF_FIELD,
-  UPB_DEF_ENUM,
-  UPB_DEF_SERVICE,   /* Not yet implemented. */
-  UPB_DEF_ANY = -1   /* Wildcard for upb_symtab_get*() */
-} upb_deftype_t;
-
-#ifdef __cplusplus
-
-/* The base class of all defs.  Its base is upb::RefCounted (use upb::upcast()
- * to convert). */
-class upb::Def {
- public:
-  typedef upb_deftype_t Type;
-
-  /* upb::RefCounted methods like Ref()/Unref(). */
-  UPB_REFCOUNTED_CPPMETHODS
-
-  Type def_type() const;
-
-  /* "fullname" is the def's fully-qualified name (eg. foo.bar.Message). */
-  const char *full_name() const;
-
-  /* The final part of a def's name (eg. Message). */
-  const char *name() const;
-
-  /* The def must be mutable.  Caller retains ownership of fullname.  Defs are
-   * not required to have a name; if a def has no name when it is frozen, it
-   * will remain an anonymous def.  On failure, returns false and details in "s"
-   * if non-NULL. */
-  bool set_full_name(const char* fullname, upb::Status* s);
-  bool set_full_name(const std::string &fullname, upb::Status* s);
-
-  /* The file in which this def appears.  It is not necessary to add a def to a
-   * file (and consequently the accessor may return NULL).  Set this by calling
-   * file->Add(def). */
-  FileDef* file() const;
-
-  /* Freezes the given defs; this validates all constraints and marks the defs
-   * as frozen (read-only).  "defs" may not contain any fielddefs, but fields
-   * of any msgdefs will be frozen.
-   *
-   * Symbolic references to sub-types and enum defaults must have already been
-   * resolved.  Any mutable defs reachable from any of "defs" must also be in
-   * the list; more formally, "defs" must be a transitive closure of mutable
-   * defs.
-   *
-   * After this operation succeeds, the finalized defs must only be accessed
-   * through a const pointer! */
-  static bool Freeze(Def* const* defs, size_t n, Status* status);
-  static bool Freeze(const std::vector<Def*>& defs, Status* status);
-
- private:
-  UPB_DISALLOW_POD_OPS(Def, upb::Def)
-};
-
-#endif  /* __cplusplus */
-
-UPB_BEGIN_EXTERN_C
-
-/* Include upb_refcounted methods like upb_def_ref()/upb_def_unref(). */
-UPB_REFCOUNTED_CMETHODS(upb_def, upb_def_upcast)
-
-upb_deftype_t upb_def_type(const upb_def *d);
-const char *upb_def_fullname(const upb_def *d);
-const char *upb_def_name(const upb_def *d);
-const upb_filedef *upb_def_file(const upb_def *d);
-bool upb_def_setfullname(upb_def *def, const char *fullname, upb_status *s);
-bool upb_def_freeze(upb_def *const *defs, size_t n, upb_status *s);
-
-/* Temporary API: for internal use only. */
-bool _upb_def_validate(upb_def *const*defs, size_t n, upb_status *s);
-
-UPB_END_EXTERN_C
-
-
-/* upb::Def casts *************************************************************/
-
-#ifdef __cplusplus
-#define UPB_CPP_CASTS(cname, cpptype)                                          \
-  namespace upb {                                                              \
-  template <>                                                                  \
-  inline cpptype *down_cast<cpptype *, Def>(Def * def) {                       \
-    return upb_downcast_##cname##_mutable(def);                                \
-  }                                                                            \
-  template <>                                                                  \
-  inline cpptype *dyn_cast<cpptype *, Def>(Def * def) {                        \
-    return upb_dyncast_##cname##_mutable(def);                                 \
-  }                                                                            \
-  template <>                                                                  \
-  inline const cpptype *down_cast<const cpptype *, const Def>(                 \
-      const Def *def) {                                                        \
-    return upb_downcast_##cname(def);                                          \
-  }                                                                            \
-  template <>                                                                  \
-  inline const cpptype *dyn_cast<const cpptype *, const Def>(const Def *def) { \
-    return upb_dyncast_##cname(def);                                           \
-  }                                                                            \
-  template <>                                                                  \
-  inline const cpptype *down_cast<const cpptype *, Def>(Def * def) {           \
-    return upb_downcast_##cname(def);                                          \
-  }                                                                            \
-  template <>                                                                  \
-  inline const cpptype *dyn_cast<const cpptype *, Def>(Def * def) {            \
-    return upb_dyncast_##cname(def);                                           \
-  }                                                                            \
-  }  /* namespace upb */
-#else
-#define UPB_CPP_CASTS(cname, cpptype)
-#endif  /* __cplusplus */
-
-/* Dynamic casts, for determining if a def is of a particular type at runtime.
- * Downcasts, for when some wants to assert that a def is of a particular type.
- * These are only checked if we are building debug. */
-#define UPB_DEF_CASTS(lower, upper, cpptype)                               \
-  UPB_INLINE const upb_##lower *upb_dyncast_##lower(const upb_def *def) {  \
-    if (upb_def_type(def) != UPB_DEF_##upper) return NULL;                 \
-    return (upb_##lower *)def;                                             \
-  }                                                                        \
-  UPB_INLINE const upb_##lower *upb_downcast_##lower(const upb_def *def) { \
-    UPB_ASSERT(upb_def_type(def) == UPB_DEF_##upper);                          \
-    return (const upb_##lower *)def;                                       \
-  }                                                                        \
-  UPB_INLINE upb_##lower *upb_dyncast_##lower##_mutable(upb_def *def) {    \
-    return (upb_##lower *)upb_dyncast_##lower(def);                        \
-  }                                                                        \
-  UPB_INLINE upb_##lower *upb_downcast_##lower##_mutable(upb_def *def) {   \
-    return (upb_##lower *)upb_downcast_##lower(def);                       \
-  }                                                                        \
-  UPB_CPP_CASTS(lower, cpptype)
-
-#define UPB_DEFINE_DEF(cppname, lower, upper, cppmethods, members)             \
-  UPB_DEFINE_CLASS2(cppname, upb::Def, upb::RefCounted, cppmethods,            \
-                   members)                                                    \
-  UPB_DEF_CASTS(lower, upper, cppname)
-
-#define UPB_DECLARE_DEF_TYPE(cppname, lower, upper) \
-  UPB_DECLARE_DERIVED_TYPE2(cppname, upb::Def, upb::RefCounted, \
-                            upb_ ## lower, upb_def, upb_refcounted) \
-  UPB_DEF_CASTS(lower, upper, cppname)
-
-UPB_DECLARE_DEF_TYPE(upb::FieldDef, fielddef, FIELD)
-UPB_DECLARE_DEF_TYPE(upb::MessageDef, msgdef, MSG)
-UPB_DECLARE_DEF_TYPE(upb::EnumDef, enumdef, ENUM)
-
-#undef UPB_DECLARE_DEF_TYPE
-#undef UPB_DEF_CASTS
-#undef UPB_CPP_CASTS
-
-
-/* upb::FieldDef **************************************************************/
-
-/* The types a field can have.  Note that this list is not identical to the
- * types defined in descriptor.proto, which gives INT32 and SINT32 separate
- * types (we distinguish the two with the "integer encoding" enum below). */
-typedef enum {
-  /* Types stored in 1 byte. */
-  UPB_TYPE_BOOL     = 1,
-  /* Types stored in 4 bytes. */
-  UPB_TYPE_FLOAT    = 2,
-  UPB_TYPE_INT32    = 3,
-  UPB_TYPE_UINT32   = 4,
-  UPB_TYPE_ENUM     = 5,  /* Enum values are int32. */
-  /* Types stored as pointers (probably 4 or 8 bytes). */
-  UPB_TYPE_STRING   = 6,
-  UPB_TYPE_BYTES    = 7,
-  UPB_TYPE_MESSAGE  = 8,
-  /* Types stored as 8 bytes. */
-  UPB_TYPE_DOUBLE   = 9,
-  UPB_TYPE_INT64    = 10,
-  UPB_TYPE_UINT64   = 11
-} upb_fieldtype_t;
-
-/* The repeated-ness of each field; this matches descriptor.proto. */
-typedef enum {
-  UPB_LABEL_OPTIONAL = 1,
-  UPB_LABEL_REQUIRED = 2,
-  UPB_LABEL_REPEATED = 3
-} upb_label_t;
-
-/* How integers should be encoded in serializations that offer multiple
- * integer encoding methods. */
-typedef enum {
-  UPB_INTFMT_VARIABLE = 1,
-  UPB_INTFMT_FIXED = 2,
-  UPB_INTFMT_ZIGZAG = 3   /* Only for signed types (INT32/INT64). */
-} upb_intfmt_t;
-
-/* Descriptor types, as defined in descriptor.proto. */
-typedef enum {
-  UPB_DESCRIPTOR_TYPE_DOUBLE   = 1,
-  UPB_DESCRIPTOR_TYPE_FLOAT    = 2,
-  UPB_DESCRIPTOR_TYPE_INT64    = 3,
-  UPB_DESCRIPTOR_TYPE_UINT64   = 4,
-  UPB_DESCRIPTOR_TYPE_INT32    = 5,
-  UPB_DESCRIPTOR_TYPE_FIXED64  = 6,
-  UPB_DESCRIPTOR_TYPE_FIXED32  = 7,
-  UPB_DESCRIPTOR_TYPE_BOOL     = 8,
-  UPB_DESCRIPTOR_TYPE_STRING   = 9,
-  UPB_DESCRIPTOR_TYPE_GROUP    = 10,
-  UPB_DESCRIPTOR_TYPE_MESSAGE  = 11,
-  UPB_DESCRIPTOR_TYPE_BYTES    = 12,
-  UPB_DESCRIPTOR_TYPE_UINT32   = 13,
-  UPB_DESCRIPTOR_TYPE_ENUM     = 14,
-  UPB_DESCRIPTOR_TYPE_SFIXED32 = 15,
-  UPB_DESCRIPTOR_TYPE_SFIXED64 = 16,
-  UPB_DESCRIPTOR_TYPE_SINT32   = 17,
-  UPB_DESCRIPTOR_TYPE_SINT64   = 18
-} upb_descriptortype_t;
+struct upb_enumdef;
+typedef struct upb_enumdef upb_enumdef;
+struct upb_fielddef;
+typedef struct upb_fielddef upb_fielddef;
+struct upb_filedef;
+typedef struct upb_filedef upb_filedef;
+struct upb_msgdef;
+typedef struct upb_msgdef upb_msgdef;
+struct upb_oneofdef;
+typedef struct upb_oneofdef upb_oneofdef;
+struct upb_symtab;
+typedef struct upb_symtab upb_symtab;
 
 typedef enum {
   UPB_SYNTAX_PROTO2 = 2,
@@ -2027,56 +3131,75 @@
   UPB_WELLKNOWN_STRUCT
 } upb_wellknowntype_t;
 
-
-/* Maps descriptor type -> upb field type.  */
-extern const uint8_t upb_desctype_to_fieldtype[];
+/* upb_fielddef ***************************************************************/
 
 /* Maximum field number allowed for FieldDefs.  This is an inherent limit of the
  * protobuf wire format. */
 #define UPB_MAX_FIELDNUMBER ((1 << 29) - 1)
 
 #ifdef __cplusplus
+extern "C" {
+#endif
+
+const char *upb_fielddef_fullname(const upb_fielddef *f);
+upb_fieldtype_t upb_fielddef_type(const upb_fielddef *f);
+upb_descriptortype_t upb_fielddef_descriptortype(const upb_fielddef *f);
+upb_label_t upb_fielddef_label(const upb_fielddef *f);
+uint32_t upb_fielddef_number(const upb_fielddef *f);
+const char *upb_fielddef_name(const upb_fielddef *f);
+bool upb_fielddef_isextension(const upb_fielddef *f);
+bool upb_fielddef_lazy(const upb_fielddef *f);
+bool upb_fielddef_packed(const upb_fielddef *f);
+size_t upb_fielddef_getjsonname(const upb_fielddef *f, char *buf, size_t len);
+const upb_msgdef *upb_fielddef_containingtype(const upb_fielddef *f);
+const upb_oneofdef *upb_fielddef_containingoneof(const upb_fielddef *f);
+uint32_t upb_fielddef_index(const upb_fielddef *f);
+bool upb_fielddef_issubmsg(const upb_fielddef *f);
+bool upb_fielddef_isstring(const upb_fielddef *f);
+bool upb_fielddef_isseq(const upb_fielddef *f);
+bool upb_fielddef_isprimitive(const upb_fielddef *f);
+bool upb_fielddef_ismap(const upb_fielddef *f);
+int64_t upb_fielddef_defaultint64(const upb_fielddef *f);
+int32_t upb_fielddef_defaultint32(const upb_fielddef *f);
+uint64_t upb_fielddef_defaultuint64(const upb_fielddef *f);
+uint32_t upb_fielddef_defaultuint32(const upb_fielddef *f);
+bool upb_fielddef_defaultbool(const upb_fielddef *f);
+float upb_fielddef_defaultfloat(const upb_fielddef *f);
+double upb_fielddef_defaultdouble(const upb_fielddef *f);
+const char *upb_fielddef_defaultstr(const upb_fielddef *f, size_t *len);
+bool upb_fielddef_hassubdef(const upb_fielddef *f);
+bool upb_fielddef_haspresence(const upb_fielddef *f);
+const upb_msgdef *upb_fielddef_msgsubdef(const upb_fielddef *f);
+const upb_enumdef *upb_fielddef_enumsubdef(const upb_fielddef *f);
+
+/* Internal only. */
+uint32_t upb_fielddef_selectorbase(const upb_fielddef *f);
+
+#ifdef __cplusplus
+}  /* extern "C" */
 
 /* A upb_fielddef describes a single field in a message.  It is most often
  * found as a part of a upb_msgdef, but can also stand alone to represent
- * an extension.
- *
- * Its base class is upb::Def (use upb::upcast() to convert). */
-class upb::FieldDef {
+ * an extension. */
+class upb::FieldDefPtr {
  public:
+  FieldDefPtr() : ptr_(nullptr) {}
+  explicit FieldDefPtr(const upb_fielddef *ptr) : ptr_(ptr) {}
+
+  const upb_fielddef* ptr() const { return ptr_; }
+  explicit operator bool() const { return ptr_ != nullptr; }
+
   typedef upb_fieldtype_t Type;
   typedef upb_label_t Label;
-  typedef upb_intfmt_t IntegerFormat;
   typedef upb_descriptortype_t DescriptorType;
 
-  /* These return true if the given value is a valid member of the enumeration. */
-  static bool CheckType(int32_t val);
-  static bool CheckLabel(int32_t val);
-  static bool CheckDescriptorType(int32_t val);
-  static bool CheckIntegerFormat(int32_t val);
+  const char* full_name() const { return upb_fielddef_fullname(ptr_); }
 
-  /* These convert to the given enumeration; they require that the value is
-   * valid. */
-  static Type ConvertType(int32_t val);
-  static Label ConvertLabel(int32_t val);
-  static DescriptorType ConvertDescriptorType(int32_t val);
-  static IntegerFormat ConvertIntegerFormat(int32_t val);
-
-  /* Returns NULL if memory allocation failed. */
-  static reffed_ptr<FieldDef> New();
-
-  /* upb::RefCounted methods like Ref()/Unref(). */
-  UPB_REFCOUNTED_CPPMETHODS
-
-  /* Functionality from upb::Def. */
-  const char* full_name() const;
-
-  bool type_is_set() const;  /* set_[descriptor_]type() has been called? */
-  Type type() const;         /* Requires that type_is_set() == true. */
-  Label label() const;       /* Defaults to UPB_LABEL_OPTIONAL. */
-  const char* name() const;  /* NULL if uninitialized. */
-  uint32_t number() const;   /* Returns 0 if uninitialized. */
-  bool is_extension() const;
+  Type type() const { return upb_fielddef_type(ptr_); }
+  Label label() const { return upb_fielddef_label(ptr_); }
+  const char* name() const { return upb_fielddef_name(ptr_); }
+  uint32_t number() const { return upb_fielddef_number(ptr_); }
+  bool is_extension() const { return upb_fielddef_isextension(ptr_); }
 
   /* Copies the JSON name for this field into the given buffer.  Returns the
    * actual size of the JSON name, including the NULL terminator.  If the
@@ -2088,7 +3211,9 @@
    * name.  However if the regular name is unset, the JSON name will be unset
    * also.
    */
-  size_t GetJsonName(char* buf, size_t len) const;
+  size_t GetJsonName(char *buf, size_t len) const {
+    return upb_fielddef_getjsonname(ptr_, buf, len);
+  }
 
   /* Convenience version of the above function which copies the JSON name
    * into the given string, returning false if the name is not set. */
@@ -2106,20 +3231,20 @@
    * TODO(haberman): I think we want to move this into a FieldOptions container
    * when we add support for custom options (the FieldOptions struct will
    * contain both regular FieldOptions like "lazy" *and* custom options). */
-  bool lazy() const;
+  bool lazy() const { return upb_fielddef_lazy(ptr_); }
 
   /* For non-string, non-submessage fields, this indicates whether binary
    * protobufs are encoded in packed or non-packed format.
    *
    * TODO(haberman): see note above about putting options like this into a
    * FieldOptions container. */
-  bool packed() const;
+  bool packed() const { return upb_fielddef_packed(ptr_); }
 
   /* An integer that can be used as an index into an array of fields for
    * whatever message this field belongs to.  Guaranteed to be less than
    * f->containing_type()->field_count().  May only be accessed once the def has
    * been finalized. */
-  uint32_t index() const;
+  uint32_t index() const { return upb_fielddef_index(ptr_); }
 
   /* The MessageDef to which this field belongs.
    *
@@ -2129,41 +3254,27 @@
    * If the field has not yet been added to a MessageDef, you can set the name
    * of the containing type symbolically instead.  This is mostly useful for
    * extensions, where the extension is declared separately from the message. */
-  const MessageDef* containing_type() const;
-  const char* containing_type_name();
+  MessageDefPtr containing_type() const;
 
   /* The OneofDef to which this field belongs, or NULL if this field is not part
    * of a oneof. */
-  const OneofDef* containing_oneof() const;
+  OneofDefPtr containing_oneof() const;
 
   /* The field's type according to the enum in descriptor.proto.  This is not
    * the same as UPB_TYPE_*, because it distinguishes between (for example)
    * INT32 and SINT32, whereas our "type" enum does not.  This return of
    * descriptor_type() is a function of type(), integer_format(), and
-   * is_tag_delimited().  Likewise set_descriptor_type() sets all three
-   * appropriately. */
-  DescriptorType descriptor_type() const;
+   * is_tag_delimited().  */
+  DescriptorType descriptor_type() const {
+    return upb_fielddef_descriptortype(ptr_);
+  }
 
   /* Convenient field type tests. */
-  bool IsSubMessage() const;
-  bool IsString() const;
-  bool IsSequence() const;
-  bool IsPrimitive() const;
-  bool IsMap() const;
-
-  /* Returns whether this field explicitly represents presence.
-   *
-   * For proto2 messages: Returns true for any scalar (non-repeated) field.
-   * For proto3 messages: Returns true for scalar submessage or oneof fields. */
-  bool HasPresence() const;
-
-  /* How integers are encoded.  Only meaningful for integer types.
-   * Defaults to UPB_INTFMT_VARIABLE, and is reset when "type" changes. */
-  IntegerFormat integer_format() const;
-
-  /* Whether a submessage field is tag-delimited or not (if false, then
-   * length-delimited).  May only be set when type() == UPB_TYPE_MESSAGE. */
-  bool is_tag_delimited() const;
+  bool IsSubMessage() const { return upb_fielddef_issubmsg(ptr_); }
+  bool IsString() const { return upb_fielddef_isstring(ptr_); }
+  bool IsSequence() const { return upb_fielddef_isseq(ptr_); }
+  bool IsPrimitive() const { return upb_fielddef_isprimitive(ptr_); }
+  bool IsMap() const { return upb_fielddef_ismap(ptr_); }
 
   /* Returns the non-string default value for this fielddef, which may either
    * be something the client set explicitly or the "default default" (0 for
@@ -2171,239 +3282,157 @@
    * returned value, except for enum fields that are still mutable.
    *
    * Requires that the given function matches the field's current type. */
-  int64_t default_int64() const;
-  int32_t default_int32() const;
-  uint64_t default_uint64() const;
-  uint32_t default_uint32() const;
-  bool default_bool() const;
-  float default_float() const;
-  double default_double() const;
+  int64_t default_int64() const { return upb_fielddef_defaultint64(ptr_); }
+  int32_t default_int32() const { return upb_fielddef_defaultint32(ptr_); }
+  uint64_t default_uint64() const { return upb_fielddef_defaultuint64(ptr_); }
+  uint32_t default_uint32() const { return upb_fielddef_defaultuint32(ptr_); }
+  bool default_bool() const { return upb_fielddef_defaultbool(ptr_); }
+  float default_float() const { return upb_fielddef_defaultfloat(ptr_); }
+  double default_double() const { return upb_fielddef_defaultdouble(ptr_); }
 
   /* The resulting string is always NULL-terminated.  If non-NULL, the length
    * will be stored in *len. */
-  const char *default_string(size_t* len) const;
-
-  /* For frozen UPB_TYPE_ENUM fields, enum defaults can always be read as either
-   * string or int32, and both of these methods will always return true.
-   *
-   * For mutable UPB_TYPE_ENUM fields, the story is a bit more complicated.
-   * Enum defaults are unusual. They can be specified either as string or int32,
-   * but to be valid the enum must have that value as a member.  And if no
-   * default is specified, the "default default" comes from the EnumDef.
-   *
-   * We allow reading the default as either an int32 or a string, but only if
-   * we have a meaningful value to report.  We have a meaningful value if it was
-   * set explicitly, or if we could get the "default default" from the EnumDef.
-   * Also if you explicitly set the name and we find the number in the EnumDef */
-  bool EnumHasStringDefault() const;
-  bool EnumHasInt32Default() const;
-
-  /* Submessage and enum fields must reference a "subdef", which is the
-   * upb::MessageDef or upb::EnumDef that defines their type.  Note that when
-   * the FieldDef is mutable it may not have a subdef *yet*, but this function
-   * still returns true to indicate that the field's type requires a subdef. */
-  bool HasSubDef() const;
+  const char *default_string(size_t * len) const {
+    return upb_fielddef_defaultstr(ptr_, len);
+  }
 
   /* Returns the enum or submessage def for this field, if any.  The field's
    * type must match (ie. you may only call enum_subdef() for fields where
-   * type() == UPB_TYPE_ENUM).  Returns NULL if the subdef has not been set or
-   * is currently set symbolically. */
-  const EnumDef* enum_subdef() const;
-  const MessageDef* message_subdef() const;
-
-  /* Returns the generic subdef for this field.  Requires that HasSubDef() (ie.
-   * only works for UPB_TYPE_ENUM and UPB_TYPE_MESSAGE fields). */
-  const Def* subdef() const;
-
-  /* Returns the symbolic name of the subdef.  If the subdef is currently set
-   * unresolved (ie. set symbolically) returns the symbolic name.  If it has
-   * been resolved to a specific subdef, returns the name from that subdef. */
-  const char* subdef_name() const;
-
-  /* Setters (non-const methods), only valid for mutable FieldDefs! ***********/
-
-  bool set_full_name(const char* fullname, upb::Status* s);
-  bool set_full_name(const std::string& fullname, upb::Status* s);
-
-  /* This may only be called if containing_type() == NULL (ie. the field has not
-   * been added to a message yet). */
-  bool set_containing_type_name(const char *name, Status* status);
-  bool set_containing_type_name(const std::string& name, Status* status);
-
-  /* Defaults to false.  When we freeze, we ensure that this can only be true
-   * for length-delimited message fields.  Prior to freezing this can be true or
-   * false with no restrictions. */
-  void set_lazy(bool lazy);
-
-  /* Defaults to true.  Sets whether this field is encoded in packed format. */
-  void set_packed(bool packed);
-
-  /* "type" or "descriptor_type" MUST be set explicitly before the fielddef is
-   * finalized.  These setters require that the enum value is valid; if the
-   * value did not come directly from an enum constant, the caller should
-   * validate it first with the functions above (CheckFieldType(), etc). */
-  void set_type(Type type);
-  void set_label(Label label);
-  void set_descriptor_type(DescriptorType type);
-  void set_is_extension(bool is_extension);
-
-  /* "number" and "name" must be set before the FieldDef is added to a
-   * MessageDef, and may not be set after that.
-   *
-   * "name" is the same as full_name()/set_full_name(), but since fielddefs
-   * most often use simple, non-qualified names, we provide this accessor
-   * also.  Generally only extensions will want to think of this name as
-   * fully-qualified. */
-  bool set_number(uint32_t number, upb::Status* s);
-  bool set_name(const char* name, upb::Status* s);
-  bool set_name(const std::string& name, upb::Status* s);
-
-  /* Sets the JSON name to the given string. */
-  /* TODO(haberman): implement.  Right now only default json_name (camelCase)
-   * is supported. */
-  bool set_json_name(const char* json_name, upb::Status* s);
-  bool set_json_name(const std::string& name, upb::Status* s);
-
-  /* Clears the JSON name. This will make it revert to its default, which is
-   * a camelCased version of the regular field name. */
-  void clear_json_name();
-
-  void set_integer_format(IntegerFormat format);
-  bool set_tag_delimited(bool tag_delimited, upb::Status* s);
-
-  /* Sets default value for the field.  The call must exactly match the type
-   * of the field.  Enum fields may use either setint32 or setstring to set
-   * the default numerically or symbolically, respectively, but symbolic
-   * defaults must be resolved before finalizing (see ResolveEnumDefault()).
-   *
-   * Changing the type of a field will reset its default. */
-  void set_default_int64(int64_t val);
-  void set_default_int32(int32_t val);
-  void set_default_uint64(uint64_t val);
-  void set_default_uint32(uint32_t val);
-  void set_default_bool(bool val);
-  void set_default_float(float val);
-  void set_default_double(double val);
-  bool set_default_string(const void *str, size_t len, Status *s);
-  bool set_default_string(const std::string &str, Status *s);
-  void set_default_cstr(const char *str, Status *s);
-
-  /* Before a fielddef is frozen, its subdef may be set either directly (with a
-   * upb::Def*) or symbolically.  Symbolic refs must be resolved before the
-   * containing msgdef can be frozen (see upb_resolve() above).  upb always
-   * guarantees that any def reachable from a live def will also be kept alive.
-   *
-   * Both methods require that upb_hassubdef(f) (so the type must be set prior
-   * to calling these methods).  Returns false if this is not the case, or if
-   * the given subdef is not of the correct type.  The subdef is reset if the
-   * field's type is changed.  The subdef can be set to NULL to clear it. */
-  bool set_subdef(const Def* subdef, Status* s);
-  bool set_enum_subdef(const EnumDef* subdef, Status* s);
-  bool set_message_subdef(const MessageDef* subdef, Status* s);
-  bool set_subdef_name(const char* name, Status* s);
-  bool set_subdef_name(const std::string &name, Status* s);
+   * type() == UPB_TYPE_ENUM). */
+  EnumDefPtr enum_subdef() const;
+  MessageDefPtr message_subdef() const;
 
  private:
-  UPB_DISALLOW_POD_OPS(FieldDef, upb::FieldDef)
+  const upb_fielddef *ptr_;
 };
 
-# endif  /* defined(__cplusplus) */
+#endif  /* __cplusplus */
 
-UPB_BEGIN_EXTERN_C
+/* upb_oneofdef ***************************************************************/
 
-/* Native C API. */
-upb_fielddef *upb_fielddef_new(const void *owner);
+#ifdef __cplusplus
+extern "C" {
+#endif
 
-/* Include upb_refcounted methods like upb_fielddef_ref(). */
-UPB_REFCOUNTED_CMETHODS(upb_fielddef, upb_fielddef_upcast2)
+typedef upb_inttable_iter upb_oneof_iter;
 
-/* Methods from upb_def. */
-const char *upb_fielddef_fullname(const upb_fielddef *f);
-bool upb_fielddef_setfullname(upb_fielddef *f, const char *fullname,
-                              upb_status *s);
+const char *upb_oneofdef_name(const upb_oneofdef *o);
+const upb_msgdef *upb_oneofdef_containingtype(const upb_oneofdef *o);
+int upb_oneofdef_numfields(const upb_oneofdef *o);
+uint32_t upb_oneofdef_index(const upb_oneofdef *o);
 
-bool upb_fielddef_typeisset(const upb_fielddef *f);
-upb_fieldtype_t upb_fielddef_type(const upb_fielddef *f);
-upb_descriptortype_t upb_fielddef_descriptortype(const upb_fielddef *f);
-upb_label_t upb_fielddef_label(const upb_fielddef *f);
-uint32_t upb_fielddef_number(const upb_fielddef *f);
-const char *upb_fielddef_name(const upb_fielddef *f);
-bool upb_fielddef_isextension(const upb_fielddef *f);
-bool upb_fielddef_lazy(const upb_fielddef *f);
-bool upb_fielddef_packed(const upb_fielddef *f);
-size_t upb_fielddef_getjsonname(const upb_fielddef *f, char *buf, size_t len);
-const upb_msgdef *upb_fielddef_containingtype(const upb_fielddef *f);
-const upb_oneofdef *upb_fielddef_containingoneof(const upb_fielddef *f);
-upb_msgdef *upb_fielddef_containingtype_mutable(upb_fielddef *f);
-const char *upb_fielddef_containingtypename(upb_fielddef *f);
-upb_intfmt_t upb_fielddef_intfmt(const upb_fielddef *f);
-uint32_t upb_fielddef_index(const upb_fielddef *f);
-bool upb_fielddef_istagdelim(const upb_fielddef *f);
-bool upb_fielddef_issubmsg(const upb_fielddef *f);
-bool upb_fielddef_isstring(const upb_fielddef *f);
-bool upb_fielddef_isseq(const upb_fielddef *f);
-bool upb_fielddef_isprimitive(const upb_fielddef *f);
-bool upb_fielddef_ismap(const upb_fielddef *f);
-bool upb_fielddef_haspresence(const upb_fielddef *f);
-int64_t upb_fielddef_defaultint64(const upb_fielddef *f);
-int32_t upb_fielddef_defaultint32(const upb_fielddef *f);
-uint64_t upb_fielddef_defaultuint64(const upb_fielddef *f);
-uint32_t upb_fielddef_defaultuint32(const upb_fielddef *f);
-bool upb_fielddef_defaultbool(const upb_fielddef *f);
-float upb_fielddef_defaultfloat(const upb_fielddef *f);
-double upb_fielddef_defaultdouble(const upb_fielddef *f);
-const char *upb_fielddef_defaultstr(const upb_fielddef *f, size_t *len);
-bool upb_fielddef_enumhasdefaultint32(const upb_fielddef *f);
-bool upb_fielddef_enumhasdefaultstr(const upb_fielddef *f);
-bool upb_fielddef_hassubdef(const upb_fielddef *f);
-const upb_def *upb_fielddef_subdef(const upb_fielddef *f);
-const upb_msgdef *upb_fielddef_msgsubdef(const upb_fielddef *f);
-const upb_enumdef *upb_fielddef_enumsubdef(const upb_fielddef *f);
-const char *upb_fielddef_subdefname(const upb_fielddef *f);
+/* Oneof lookups:
+ * - ntof:  look up a field by name.
+ * - ntofz: look up a field by name (as a null-terminated string).
+ * - itof:  look up a field by number. */
+const upb_fielddef *upb_oneofdef_ntof(const upb_oneofdef *o,
+                                      const char *name, size_t length);
+UPB_INLINE const upb_fielddef *upb_oneofdef_ntofz(const upb_oneofdef *o,
+                                                  const char *name) {
+  return upb_oneofdef_ntof(o, name, strlen(name));
+}
+const upb_fielddef *upb_oneofdef_itof(const upb_oneofdef *o, uint32_t num);
 
-void upb_fielddef_settype(upb_fielddef *f, upb_fieldtype_t type);
-void upb_fielddef_setdescriptortype(upb_fielddef *f, int type);
-void upb_fielddef_setlabel(upb_fielddef *f, upb_label_t label);
-bool upb_fielddef_setnumber(upb_fielddef *f, uint32_t number, upb_status *s);
-bool upb_fielddef_setname(upb_fielddef *f, const char *name, upb_status *s);
-bool upb_fielddef_setjsonname(upb_fielddef *f, const char *name, upb_status *s);
-bool upb_fielddef_clearjsonname(upb_fielddef *f);
-bool upb_fielddef_setcontainingtypename(upb_fielddef *f, const char *name,
-                                        upb_status *s);
-void upb_fielddef_setisextension(upb_fielddef *f, bool is_extension);
-void upb_fielddef_setlazy(upb_fielddef *f, bool lazy);
-void upb_fielddef_setpacked(upb_fielddef *f, bool packed);
-void upb_fielddef_setintfmt(upb_fielddef *f, upb_intfmt_t fmt);
-void upb_fielddef_settagdelim(upb_fielddef *f, bool tag_delim);
-void upb_fielddef_setdefaultint64(upb_fielddef *f, int64_t val);
-void upb_fielddef_setdefaultint32(upb_fielddef *f, int32_t val);
-void upb_fielddef_setdefaultuint64(upb_fielddef *f, uint64_t val);
-void upb_fielddef_setdefaultuint32(upb_fielddef *f, uint32_t val);
-void upb_fielddef_setdefaultbool(upb_fielddef *f, bool val);
-void upb_fielddef_setdefaultfloat(upb_fielddef *f, float val);
-void upb_fielddef_setdefaultdouble(upb_fielddef *f, double val);
-bool upb_fielddef_setdefaultstr(upb_fielddef *f, const void *str, size_t len,
-                                upb_status *s);
-void upb_fielddef_setdefaultcstr(upb_fielddef *f, const char *str,
-                                 upb_status *s);
-bool upb_fielddef_setsubdef(upb_fielddef *f, const upb_def *subdef,
-                            upb_status *s);
-bool upb_fielddef_setmsgsubdef(upb_fielddef *f, const upb_msgdef *subdef,
-                               upb_status *s);
-bool upb_fielddef_setenumsubdef(upb_fielddef *f, const upb_enumdef *subdef,
-                                upb_status *s);
-bool upb_fielddef_setsubdefname(upb_fielddef *f, const char *name,
-                                upb_status *s);
+/*  upb_oneof_iter i;
+ *  for(upb_oneof_begin(&i, e); !upb_oneof_done(&i); upb_oneof_next(&i)) {
+ *    // ...
+ *  }
+ */
+void upb_oneof_begin(upb_oneof_iter *iter, const upb_oneofdef *o);
+void upb_oneof_next(upb_oneof_iter *iter);
+bool upb_oneof_done(upb_oneof_iter *iter);
+upb_fielddef *upb_oneof_iter_field(const upb_oneof_iter *iter);
+void upb_oneof_iter_setdone(upb_oneof_iter *iter);
+bool upb_oneof_iter_isequal(const upb_oneof_iter *iter1,
+                            const upb_oneof_iter *iter2);
 
-bool upb_fielddef_checklabel(int32_t label);
-bool upb_fielddef_checktype(int32_t type);
-bool upb_fielddef_checkdescriptortype(int32_t type);
-bool upb_fielddef_checkintfmt(int32_t fmt);
+#ifdef __cplusplus
+}  /* extern "C" */
 
-UPB_END_EXTERN_C
+/* Class that represents a oneof. */
+class upb::OneofDefPtr {
+ public:
+  OneofDefPtr() : ptr_(nullptr) {}
+  explicit OneofDefPtr(const upb_oneofdef *ptr) : ptr_(ptr) {}
 
+  const upb_oneofdef* ptr() const { return ptr_; }
+  explicit operator bool() { return ptr_ != nullptr; }
 
-/* upb::MessageDef ************************************************************/
+  /* Returns the MessageDef that owns this OneofDef. */
+  MessageDefPtr containing_type() const;
+
+  /* Returns the name of this oneof. This is the name used to look up the oneof
+   * by name once added to a message def. */
+  const char* name() const { return upb_oneofdef_name(ptr_); }
+
+  /* Returns the number of fields currently defined in the oneof. */
+  int field_count() const { return upb_oneofdef_numfields(ptr_); }
+
+  /* Looks up by name. */
+  FieldDefPtr FindFieldByName(const char *name, size_t len) const {
+    return FieldDefPtr(upb_oneofdef_ntof(ptr_, name, len));
+  }
+  FieldDefPtr FindFieldByName(const char* name) const {
+    return FieldDefPtr(upb_oneofdef_ntofz(ptr_, name));
+  }
+
+  template <class T>
+  FieldDefPtr FindFieldByName(const T& str) const {
+    return FindFieldByName(str.c_str(), str.size());
+  }
+
+  /* Looks up by tag number. */
+  FieldDefPtr FindFieldByNumber(uint32_t num) const {
+    return FieldDefPtr(upb_oneofdef_itof(ptr_, num));
+  }
+
+  class const_iterator
+      : public std::iterator<std::forward_iterator_tag, FieldDefPtr> {
+   public:
+    void operator++() { upb_oneof_next(&iter_); }
+
+    FieldDefPtr operator*() const {
+      return FieldDefPtr(upb_oneof_iter_field(&iter_));
+    }
+
+    bool operator!=(const const_iterator& other) const {
+      return !upb_oneof_iter_isequal(&iter_, &other.iter_);
+    }
+
+    bool operator==(const const_iterator& other) const {
+      return upb_oneof_iter_isequal(&iter_, &other.iter_);
+    }
+
+   private:
+    friend class OneofDefPtr;
+
+    const_iterator() {}
+    explicit const_iterator(OneofDefPtr o) {
+      upb_oneof_begin(&iter_, o.ptr());
+    }
+    static const_iterator end() {
+      const_iterator iter;
+      upb_oneof_iter_setdone(&iter.iter_);
+      return iter;
+    }
+
+    upb_oneof_iter iter_;
+  };
+
+  const_iterator begin() const { return const_iterator(*this); }
+  const_iterator end() const { return const_iterator::end(); }
+
+ private:
+  const upb_oneofdef *ptr_;
+};
+
+inline upb::OneofDefPtr upb::FieldDefPtr::containing_oneof() const {
+  return OneofDefPtr(upb_fielddef_containingoneof(ptr_));
+}
+
+#endif  /* __cplusplus */
+
+/* upb_msgdef *****************************************************************/
 
 typedef upb_inttable_iter upb_msg_field_iter;
 typedef upb_strtable_iter upb_msg_oneof_iter;
@@ -2425,299 +3454,24 @@
 #define UPB_TIMESTAMP_NANOS 2
 
 #ifdef __cplusplus
-
-/* Structure that describes a single .proto message type.
- *
- * Its base class is upb::Def (use upb::upcast() to convert). */
-class upb::MessageDef {
- public:
-  /* Returns NULL if memory allocation failed. */
-  static reffed_ptr<MessageDef> New();
-
-  /* upb::RefCounted methods like Ref()/Unref(). */
-  UPB_REFCOUNTED_CPPMETHODS
-
-  /* Functionality from upb::Def. */
-  const char* full_name() const;
-  const char* name() const;
-  bool set_full_name(const char* fullname, Status* s);
-  bool set_full_name(const std::string& fullname, Status* s);
-
-  /* Call to freeze this MessageDef.
-   * WARNING: this will fail if this message has any unfrozen submessages!
-   * Messages with cycles must be frozen as a batch using upb::Def::Freeze(). */
-  bool Freeze(Status* s);
-
-  /* The number of fields that belong to the MessageDef. */
-  int field_count() const;
-
-  /* The number of oneofs that belong to the MessageDef. */
-  int oneof_count() const;
-
-  /* Adds a field (upb_fielddef object) to a msgdef.  Requires that the msgdef
-   * and the fielddefs are mutable.  The fielddef's name and number must be
-   * set, and the message may not already contain any field with this name or
-   * number, and this fielddef may not be part of another message.  In error
-   * cases false is returned and the msgdef is unchanged.
-   *
-   * If the given field is part of a oneof, this call succeeds if and only if
-   * that oneof is already part of this msgdef. (Note that adding a oneof to a
-   * msgdef automatically adds all of its fields to the msgdef at the time that
-   * the oneof is added, so it is usually more idiomatic to add the oneof's
-   * fields first then add the oneof to the msgdef. This case is supported for
-   * convenience.)
-   *
-   * If |f| is already part of this MessageDef, this method performs no action
-   * and returns true (success). Thus, this method is idempotent. */
-  bool AddField(FieldDef* f, Status* s);
-  bool AddField(const reffed_ptr<FieldDef>& f, Status* s);
-
-  /* Adds a oneof (upb_oneofdef object) to a msgdef. Requires that the msgdef,
-   * oneof, and any fielddefs are mutable, that the fielddefs contained in the
-   * oneof do not have any name or number conflicts with existing fields in the
-   * msgdef, and that the oneof's name is unique among all oneofs in the msgdef.
-   * If the oneof is added successfully, all of its fields will be added
-   * directly to the msgdef as well. In error cases, false is returned and the
-   * msgdef is unchanged. */
-  bool AddOneof(OneofDef* o, Status* s);
-  bool AddOneof(const reffed_ptr<OneofDef>& o, Status* s);
-
-  upb_syntax_t syntax() const;
-
-  /* Returns false if we don't support this syntax value. */
-  bool set_syntax(upb_syntax_t syntax);
-
-  /* Set this to false to indicate that primitive fields should not have
-   * explicit presence information associated with them.  This will affect all
-   * fields added to this message.  Defaults to true. */
-  void SetPrimitivesHavePresence(bool have_presence);
-
-  /* These return NULL if the field is not found. */
-  FieldDef* FindFieldByNumber(uint32_t number);
-  FieldDef* FindFieldByName(const char *name, size_t len);
-  const FieldDef* FindFieldByNumber(uint32_t number) const;
-  const FieldDef* FindFieldByName(const char* name, size_t len) const;
-
-
-  FieldDef* FindFieldByName(const char *name) {
-    return FindFieldByName(name, strlen(name));
-  }
-  const FieldDef* FindFieldByName(const char *name) const {
-    return FindFieldByName(name, strlen(name));
-  }
-
-  template <class T>
-  FieldDef* FindFieldByName(const T& str) {
-    return FindFieldByName(str.c_str(), str.size());
-  }
-  template <class T>
-  const FieldDef* FindFieldByName(const T& str) const {
-    return FindFieldByName(str.c_str(), str.size());
-  }
-
-  OneofDef* FindOneofByName(const char* name, size_t len);
-  const OneofDef* FindOneofByName(const char* name, size_t len) const;
-
-  OneofDef* FindOneofByName(const char* name) {
-    return FindOneofByName(name, strlen(name));
-  }
-  const OneofDef* FindOneofByName(const char* name) const {
-    return FindOneofByName(name, strlen(name));
-  }
-
-  template<class T>
-  OneofDef* FindOneofByName(const T& str) {
-    return FindOneofByName(str.c_str(), str.size());
-  }
-  template<class T>
-  const OneofDef* FindOneofByName(const T& str) const {
-    return FindOneofByName(str.c_str(), str.size());
-  }
-
-  /* Is this message a map entry? */
-  void setmapentry(bool map_entry);
-  bool mapentry() const;
-
-  /* Return the type of well known type message. UPB_WELLKNOWN_UNSPECIFIED for
-   * non-well-known message. */
-  upb_wellknowntype_t wellknowntype() const;
-
-  /* Whether is a number wrapper. */
-  bool isnumberwrapper() const;
-
-  /* Iteration over fields.  The order is undefined. */
-  class field_iterator
-      : public std::iterator<std::forward_iterator_tag, FieldDef*> {
-   public:
-    explicit field_iterator(MessageDef* md);
-    static field_iterator end(MessageDef* md);
-
-    void operator++();
-    FieldDef* operator*() const;
-    bool operator!=(const field_iterator& other) const;
-    bool operator==(const field_iterator& other) const;
-
-   private:
-    upb_msg_field_iter iter_;
-  };
-
-  class const_field_iterator
-      : public std::iterator<std::forward_iterator_tag, const FieldDef*> {
-   public:
-    explicit const_field_iterator(const MessageDef* md);
-    static const_field_iterator end(const MessageDef* md);
-
-    void operator++();
-    const FieldDef* operator*() const;
-    bool operator!=(const const_field_iterator& other) const;
-    bool operator==(const const_field_iterator& other) const;
-
-   private:
-    upb_msg_field_iter iter_;
-  };
-
-  /* Iteration over oneofs. The order is undefined. */
-  class oneof_iterator
-      : public std::iterator<std::forward_iterator_tag, FieldDef*> {
-   public:
-    explicit oneof_iterator(MessageDef* md);
-    static oneof_iterator end(MessageDef* md);
-
-    void operator++();
-    OneofDef* operator*() const;
-    bool operator!=(const oneof_iterator& other) const;
-    bool operator==(const oneof_iterator& other) const;
-
-   private:
-    upb_msg_oneof_iter iter_;
-  };
-
-  class const_oneof_iterator
-      : public std::iterator<std::forward_iterator_tag, const FieldDef*> {
-   public:
-    explicit const_oneof_iterator(const MessageDef* md);
-    static const_oneof_iterator end(const MessageDef* md);
-
-    void operator++();
-    const OneofDef* operator*() const;
-    bool operator!=(const const_oneof_iterator& other) const;
-    bool operator==(const const_oneof_iterator& other) const;
-
-   private:
-    upb_msg_oneof_iter iter_;
-  };
-
-  class FieldAccessor {
-   public:
-    explicit FieldAccessor(MessageDef* msg) : msg_(msg) {}
-    field_iterator begin() { return msg_->field_begin(); }
-    field_iterator end() { return msg_->field_end(); }
-   private:
-    MessageDef* msg_;
-  };
-
-  class ConstFieldAccessor {
-   public:
-    explicit ConstFieldAccessor(const MessageDef* msg) : msg_(msg) {}
-    const_field_iterator begin() { return msg_->field_begin(); }
-    const_field_iterator end() { return msg_->field_end(); }
-   private:
-    const MessageDef* msg_;
-  };
-
-  class OneofAccessor {
-   public:
-    explicit OneofAccessor(MessageDef* msg) : msg_(msg) {}
-    oneof_iterator begin() { return msg_->oneof_begin(); }
-    oneof_iterator end() { return msg_->oneof_end(); }
-   private:
-    MessageDef* msg_;
-  };
-
-  class ConstOneofAccessor {
-   public:
-    explicit ConstOneofAccessor(const MessageDef* msg) : msg_(msg) {}
-    const_oneof_iterator begin() { return msg_->oneof_begin(); }
-    const_oneof_iterator end() { return msg_->oneof_end(); }
-   private:
-    const MessageDef* msg_;
-  };
-
-  field_iterator field_begin();
-  field_iterator field_end();
-  const_field_iterator field_begin() const;
-  const_field_iterator field_end() const;
-
-  oneof_iterator oneof_begin();
-  oneof_iterator oneof_end();
-  const_oneof_iterator oneof_begin() const;
-  const_oneof_iterator oneof_end() const;
-
-  FieldAccessor fields() { return FieldAccessor(this); }
-  ConstFieldAccessor fields() const { return ConstFieldAccessor(this); }
-  OneofAccessor oneofs() { return OneofAccessor(this); }
-  ConstOneofAccessor oneofs() const { return ConstOneofAccessor(this); }
-
- private:
-  UPB_DISALLOW_POD_OPS(MessageDef, upb::MessageDef)
-};
-
-#endif  /* __cplusplus */
-
-UPB_BEGIN_EXTERN_C
-
-/* Returns NULL if memory allocation failed. */
-upb_msgdef *upb_msgdef_new(const void *owner);
-
-/* Include upb_refcounted methods like upb_msgdef_ref(). */
-UPB_REFCOUNTED_CMETHODS(upb_msgdef, upb_msgdef_upcast2)
-
-bool upb_msgdef_freeze(upb_msgdef *m, upb_status *status);
+extern "C" {
+#endif
 
 const char *upb_msgdef_fullname(const upb_msgdef *m);
+const upb_filedef *upb_msgdef_file(const upb_msgdef *m);
 const char *upb_msgdef_name(const upb_msgdef *m);
 int upb_msgdef_numoneofs(const upb_msgdef *m);
 upb_syntax_t upb_msgdef_syntax(const upb_msgdef *m);
-
-bool upb_msgdef_addfield(upb_msgdef *m, upb_fielddef *f, const void *ref_donor,
-                         upb_status *s);
-bool upb_msgdef_addoneof(upb_msgdef *m, upb_oneofdef *o, const void *ref_donor,
-                         upb_status *s);
-bool upb_msgdef_setfullname(upb_msgdef *m, const char *fullname, upb_status *s);
-void upb_msgdef_setmapentry(upb_msgdef *m, bool map_entry);
 bool upb_msgdef_mapentry(const upb_msgdef *m);
 upb_wellknowntype_t upb_msgdef_wellknowntype(const upb_msgdef *m);
 bool upb_msgdef_isnumberwrapper(const upb_msgdef *m);
 bool upb_msgdef_setsyntax(upb_msgdef *m, upb_syntax_t syntax);
-
-/* Field lookup in a couple of different variations:
- *   - itof = int to field
- *   - ntof = name to field
- *   - ntofz = name to field, null-terminated string. */
 const upb_fielddef *upb_msgdef_itof(const upb_msgdef *m, uint32_t i);
 const upb_fielddef *upb_msgdef_ntof(const upb_msgdef *m, const char *name,
                                     size_t len);
-int upb_msgdef_numfields(const upb_msgdef *m);
-
-UPB_INLINE const upb_fielddef *upb_msgdef_ntofz(const upb_msgdef *m,
-                                                const char *name) {
-  return upb_msgdef_ntof(m, name, strlen(name));
-}
-
-UPB_INLINE upb_fielddef *upb_msgdef_itof_mutable(upb_msgdef *m, uint32_t i) {
-  return (upb_fielddef*)upb_msgdef_itof(m, i);
-}
-
-UPB_INLINE upb_fielddef *upb_msgdef_ntof_mutable(upb_msgdef *m,
-                                                 const char *name, size_t len) {
-  return (upb_fielddef *)upb_msgdef_ntof(m, name, len);
-}
-
-/* Oneof lookup:
- *   - ntoo = name to oneof
- *   - ntooz = name to oneof, null-terminated string. */
 const upb_oneofdef *upb_msgdef_ntoo(const upb_msgdef *m, const char *name,
                                     size_t len);
+int upb_msgdef_numfields(const upb_msgdef *m);
 int upb_msgdef_numoneofs(const upb_msgdef *m);
 
 UPB_INLINE const upb_oneofdef *upb_msgdef_ntooz(const upb_msgdef *m,
@@ -2725,11 +3479,15 @@
   return upb_msgdef_ntoo(m, name, strlen(name));
 }
 
-UPB_INLINE upb_oneofdef *upb_msgdef_ntoo_mutable(upb_msgdef *m,
-                                                 const char *name, size_t len) {
-  return (upb_oneofdef *)upb_msgdef_ntoo(m, name, len);
+UPB_INLINE const upb_fielddef *upb_msgdef_ntofz(const upb_msgdef *m,
+                                                const char *name) {
+  return upb_msgdef_ntof(m, name, strlen(name));
 }
 
+/* Internal-only. */
+size_t upb_msgdef_selectorcount(const upb_msgdef *m);
+uint32_t upb_msgdef_submsgfieldcount(const upb_msgdef *m);
+
 /* Lookup of either field or oneof by name.  Returns whether either was found.
  * If the return is true, then the found def will be set, and the non-found
  * one set to NULL. */
@@ -2760,115 +3518,216 @@
 bool upb_msg_field_done(const upb_msg_field_iter *iter);
 upb_fielddef *upb_msg_iter_field(const upb_msg_field_iter *iter);
 void upb_msg_field_iter_setdone(upb_msg_field_iter *iter);
+bool upb_msg_field_iter_isequal(const upb_msg_field_iter * iter1,
+                                const upb_msg_field_iter * iter2);
 
 /* Similar to above, we also support iterating through the oneofs in a
  * msgdef. */
-void upb_msg_oneof_begin(upb_msg_oneof_iter *iter, const upb_msgdef *m);
-void upb_msg_oneof_next(upb_msg_oneof_iter *iter);
+void upb_msg_oneof_begin(upb_msg_oneof_iter * iter, const upb_msgdef *m);
+void upb_msg_oneof_next(upb_msg_oneof_iter * iter);
 bool upb_msg_oneof_done(const upb_msg_oneof_iter *iter);
-upb_oneofdef *upb_msg_iter_oneof(const upb_msg_oneof_iter *iter);
-void upb_msg_oneof_iter_setdone(upb_msg_oneof_iter *iter);
-
-UPB_END_EXTERN_C
-
-
-/* upb::EnumDef ***************************************************************/
-
-typedef upb_strtable_iter upb_enum_iter;
+const upb_oneofdef *upb_msg_iter_oneof(const upb_msg_oneof_iter *iter);
+void upb_msg_oneof_iter_setdone(upb_msg_oneof_iter * iter);
+bool upb_msg_oneof_iter_isequal(const upb_msg_oneof_iter *iter1,
+                                const upb_msg_oneof_iter *iter2);
 
 #ifdef __cplusplus
+}  /* extern "C" */
 
-/* Class that represents an enum.  Its base class is upb::Def (convert with
- * upb::upcast()). */
-class upb::EnumDef {
+/* Structure that describes a single .proto message type. */
+class upb::MessageDefPtr {
  public:
-  /* Returns NULL if memory allocation failed. */
-  static reffed_ptr<EnumDef> New();
+  MessageDefPtr() : ptr_(nullptr) {}
+  explicit MessageDefPtr(const upb_msgdef *ptr) : ptr_(ptr) {}
 
-  /* upb::RefCounted methods like Ref()/Unref(). */
-  UPB_REFCOUNTED_CPPMETHODS
+  const upb_msgdef *ptr() const { return ptr_; }
+  explicit operator bool() const { return ptr_ != nullptr; }
 
-  /* Functionality from upb::Def. */
-  const char* full_name() const;
-  const char* name() const;
-  bool set_full_name(const char* fullname, Status* s);
-  bool set_full_name(const std::string& fullname, Status* s);
+  const char* full_name() const { return upb_msgdef_fullname(ptr_); }
+  const char* name() const { return upb_msgdef_name(ptr_); }
 
-  /* Call to freeze this EnumDef. */
-  bool Freeze(Status* s);
+  /* The number of fields that belong to the MessageDef. */
+  int field_count() const { return upb_msgdef_numfields(ptr_); }
 
-  /* The value that is used as the default when no field default is specified.
-   * If not set explicitly, the first value that was added will be used.
-   * The default value must be a member of the enum.
-   * Requires that value_count() > 0. */
-  int32_t default_value() const;
+  /* The number of oneofs that belong to the MessageDef. */
+  int oneof_count() const { return upb_msgdef_numoneofs(ptr_); }
 
-  /* Sets the default value.  If this value is not valid, returns false and an
-   * error message in status. */
-  bool set_default_value(int32_t val, Status* status);
+  upb_syntax_t syntax() const { return upb_msgdef_syntax(ptr_); }
 
-  /* Returns the number of values currently defined in the enum.  Note that
-   * multiple names can refer to the same number, so this may be greater than
-   * the total number of unique numbers. */
-  int value_count() const;
+  /* These return null pointers if the field is not found. */
+  FieldDefPtr FindFieldByNumber(uint32_t number) const {
+    return FieldDefPtr(upb_msgdef_itof(ptr_, number));
+  }
+  FieldDefPtr FindFieldByName(const char* name, size_t len) const {
+    return FieldDefPtr(upb_msgdef_ntof(ptr_, name, len));
+  }
+  FieldDefPtr FindFieldByName(const char *name) const {
+    return FieldDefPtr(upb_msgdef_ntofz(ptr_, name));
+  }
 
-  /* Adds a single name/number pair to the enum.  Fails if this name has
-   * already been used by another value. */
-  bool AddValue(const char* name, int32_t num, Status* status);
-  bool AddValue(const std::string& name, int32_t num, Status* status);
+  template <class T>
+  FieldDefPtr FindFieldByName(const T& str) const {
+    return FindFieldByName(str.c_str(), str.size());
+  }
 
-  /* Lookups from name to integer, returning true if found. */
-  bool FindValueByName(const char* name, int32_t* num) const;
+  OneofDefPtr FindOneofByName(const char* name, size_t len) const {
+    return OneofDefPtr(upb_msgdef_ntoo(ptr_, name, len));
+  }
 
-  /* Finds the name corresponding to the given number, or NULL if none was
-   * found.  If more than one name corresponds to this number, returns the
-   * first one that was added. */
-  const char* FindValueByNumber(int32_t num) const;
+  OneofDefPtr FindOneofByName(const char *name) const {
+    return OneofDefPtr(upb_msgdef_ntooz(ptr_, name));
+  }
 
-  /* Iteration over name/value pairs.  The order is undefined.
-   * Adding an enum val invalidates any iterators.
-   *
-   * TODO: make compatible with range-for, with elements as pairs? */
-  class Iterator {
+  template <class T>
+  OneofDefPtr FindOneofByName(const T &str) const {
+    return FindOneofByName(str.c_str(), str.size());
+  }
+
+  /* Is this message a map entry? */
+  bool mapentry() const { return upb_msgdef_mapentry(ptr_); }
+
+  /* Return the type of well known type message. UPB_WELLKNOWN_UNSPECIFIED for
+   * non-well-known message. */
+  upb_wellknowntype_t wellknowntype() const {
+    return upb_msgdef_wellknowntype(ptr_);
+  }
+
+  /* Whether is a number wrapper. */
+  bool isnumberwrapper() const { return upb_msgdef_isnumberwrapper(ptr_); }
+
+  /* Iteration over fields.  The order is undefined. */
+  class const_field_iterator
+      : public std::iterator<std::forward_iterator_tag, FieldDefPtr> {
    public:
-    explicit Iterator(const EnumDef*);
+    void operator++() { upb_msg_field_next(&iter_); }
 
-    int32_t number();
-    const char *name();
-    bool Done();
-    void Next();
+    FieldDefPtr operator*() const {
+      return FieldDefPtr(upb_msg_iter_field(&iter_));
+    }
+
+    bool operator!=(const const_field_iterator &other) const {
+      return !upb_msg_field_iter_isequal(&iter_, &other.iter_);
+    }
+
+    bool operator==(const const_field_iterator &other) const {
+      return upb_msg_field_iter_isequal(&iter_, &other.iter_);
+    }
 
    private:
-    upb_enum_iter iter_;
+    friend class MessageDefPtr;
+
+    explicit const_field_iterator() {}
+
+    explicit const_field_iterator(MessageDefPtr msg) {
+      upb_msg_field_begin(&iter_, msg.ptr());
+    }
+
+    static const_field_iterator end() {
+      const_field_iterator iter;
+      upb_msg_field_iter_setdone(&iter.iter_);
+      return iter;
+    }
+
+    upb_msg_field_iter iter_;
   };
 
+  /* Iteration over oneofs. The order is undefined. */
+  class const_oneof_iterator
+      : public std::iterator<std::forward_iterator_tag, OneofDefPtr> {
+   public:
+
+    void operator++() { upb_msg_oneof_next(&iter_); }
+
+    OneofDefPtr operator*() const {
+      return OneofDefPtr(upb_msg_iter_oneof(&iter_));
+    }
+
+    bool operator!=(const const_oneof_iterator& other) const {
+      return !upb_msg_oneof_iter_isequal(&iter_, &other.iter_);
+    }
+
+    bool operator==(const const_oneof_iterator &other) const {
+      return upb_msg_oneof_iter_isequal(&iter_, &other.iter_);
+    }
+
+   private:
+    friend class MessageDefPtr;
+
+    const_oneof_iterator() {}
+
+    explicit const_oneof_iterator(MessageDefPtr msg) {
+      upb_msg_oneof_begin(&iter_, msg.ptr());
+    }
+
+    static const_oneof_iterator end() {
+      const_oneof_iterator iter;
+      upb_msg_oneof_iter_setdone(&iter.iter_);
+      return iter;
+    }
+
+    upb_msg_oneof_iter iter_;
+  };
+
+  class ConstFieldAccessor {
+   public:
+    explicit ConstFieldAccessor(const upb_msgdef* md) : md_(md) {}
+    const_field_iterator begin() { return MessageDefPtr(md_).field_begin(); }
+    const_field_iterator end() { return MessageDefPtr(md_).field_end(); }
+   private:
+    const upb_msgdef* md_;
+  };
+
+  class ConstOneofAccessor {
+   public:
+    explicit ConstOneofAccessor(const upb_msgdef* md) : md_(md) {}
+    const_oneof_iterator begin() { return MessageDefPtr(md_).oneof_begin(); }
+    const_oneof_iterator end() { return MessageDefPtr(md_).oneof_end(); }
+   private:
+    const upb_msgdef* md_;
+  };
+
+  const_field_iterator field_begin() const {
+    return const_field_iterator(*this);
+  }
+
+  const_field_iterator field_end() const { return const_field_iterator::end(); }
+
+  const_oneof_iterator oneof_begin() const {
+    return const_oneof_iterator(*this);
+  }
+
+  const_oneof_iterator oneof_end() const { return const_oneof_iterator::end(); }
+
+  ConstFieldAccessor fields() const { return ConstFieldAccessor(ptr()); }
+  ConstOneofAccessor oneofs() const { return ConstOneofAccessor(ptr()); }
+
  private:
-  UPB_DISALLOW_POD_OPS(EnumDef, upb::EnumDef)
+  const upb_msgdef* ptr_;
 };
 
+inline upb::MessageDefPtr upb::FieldDefPtr::message_subdef() const {
+  return MessageDefPtr(upb_fielddef_msgsubdef(ptr_));
+}
+
+inline upb::MessageDefPtr upb::FieldDefPtr::containing_type() const {
+  return MessageDefPtr(upb_fielddef_containingtype(ptr_));
+}
+
+inline upb::MessageDefPtr upb::OneofDefPtr::containing_type() const {
+  return MessageDefPtr(upb_oneofdef_containingtype(ptr_));
+}
+
 #endif  /* __cplusplus */
 
-UPB_BEGIN_EXTERN_C
+/* upb_enumdef ****************************************************************/
 
-/* Native C API. */
-upb_enumdef *upb_enumdef_new(const void *owner);
+typedef upb_strtable_iter upb_enum_iter;
 
-/* Include upb_refcounted methods like upb_enumdef_ref(). */
-UPB_REFCOUNTED_CMETHODS(upb_enumdef, upb_enumdef_upcast2)
-
-bool upb_enumdef_freeze(upb_enumdef *e, upb_status *status);
-
-/* From upb_def. */
 const char *upb_enumdef_fullname(const upb_enumdef *e);
 const char *upb_enumdef_name(const upb_enumdef *e);
-bool upb_enumdef_setfullname(upb_enumdef *e, const char *fullname,
-                             upb_status *s);
-
+const upb_filedef *upb_enumdef_file(const upb_enumdef *e);
 int32_t upb_enumdef_default(const upb_enumdef *e);
-bool upb_enumdef_setdefault(upb_enumdef *e, int32_t val, upb_status *s);
 int upb_enumdef_numvals(const upb_enumdef *e);
-bool upb_enumdef_addval(upb_enumdef *e, const char *name, int32_t num,
-                        upb_status *status);
 
 /* Enum lookups:
  * - ntoi:  look up a name with specified length.
@@ -2894,1073 +3753,204 @@
 const char *upb_enum_iter_name(upb_enum_iter *iter);
 int32_t upb_enum_iter_number(upb_enum_iter *iter);
 
-UPB_END_EXTERN_C
-
-
-/* upb::OneofDef **************************************************************/
-
-typedef upb_inttable_iter upb_oneof_iter;
-
 #ifdef __cplusplus
 
-/* Class that represents a oneof. */
-class upb::OneofDef {
+class upb::EnumDefPtr {
  public:
-  /* Returns NULL if memory allocation failed. */
-  static reffed_ptr<OneofDef> New();
+  EnumDefPtr() : ptr_(nullptr) {}
+  explicit EnumDefPtr(const upb_enumdef* ptr) : ptr_(ptr) {}
 
-  /* upb::RefCounted methods like Ref()/Unref(). */
-  UPB_REFCOUNTED_CPPMETHODS
+  const upb_enumdef* ptr() const { return ptr_; }
+  explicit operator bool() const { return ptr_ != nullptr; }
 
-  /* Returns the MessageDef that owns this OneofDef. */
-  const MessageDef* containing_type() const;
+  const char* full_name() const { return upb_enumdef_fullname(ptr_); }
+  const char* name() const { return upb_enumdef_name(ptr_); }
 
-  /* Returns the name of this oneof. This is the name used to look up the oneof
-   * by name once added to a message def. */
-  const char* name() const;
-  bool set_name(const char* name, Status* s);
-  bool set_name(const std::string& name, Status* s);
+  /* The value that is used as the default when no field default is specified.
+   * If not set explicitly, the first value that was added will be used.
+   * The default value must be a member of the enum.
+   * Requires that value_count() > 0. */
+  int32_t default_value() const { return upb_enumdef_default(ptr_); }
 
-  /* Returns the number of fields currently defined in the oneof. */
-  int field_count() const;
+  /* Returns the number of values currently defined in the enum.  Note that
+   * multiple names can refer to the same number, so this may be greater than
+   * the total number of unique numbers. */
+  int value_count() const { return upb_enumdef_numvals(ptr_); }
 
-  /* Adds a field to the oneof. The field must not have been added to any other
-   * oneof or msgdef. If the oneof is not yet part of a msgdef, then when the
-   * oneof is eventually added to a msgdef, all fields added to the oneof will
-   * also be added to the msgdef at that time. If the oneof is already part of a
-   * msgdef, the field must either be a part of that msgdef already, or must not
-   * be a part of any msgdef; in the latter case, the field is added to the
-   * msgdef as a part of this operation.
+  /* Lookups from name to integer, returning true if found. */
+  bool FindValueByName(const char *name, int32_t *num) const {
+    return upb_enumdef_ntoiz(ptr_, name, num);
+  }
+
+  /* Finds the name corresponding to the given number, or NULL if none was
+   * found.  If more than one name corresponds to this number, returns the
+   * first one that was added. */
+  const char *FindValueByNumber(int32_t num) const {
+    return upb_enumdef_iton(ptr_, num);
+  }
+
+  /* Iteration over name/value pairs.  The order is undefined.
+   * Adding an enum val invalidates any iterators.
    *
-   * The field may only have an OPTIONAL label, never REQUIRED or REPEATED.
-   *
-   * If |f| is already part of this MessageDef, this method performs no action
-   * and returns true (success). Thus, this method is idempotent. */
-  bool AddField(FieldDef* field, Status* s);
-  bool AddField(const reffed_ptr<FieldDef>& field, Status* s);
-
-  /* Looks up by name. */
-  const FieldDef* FindFieldByName(const char* name, size_t len) const;
-  FieldDef* FindFieldByName(const char* name, size_t len);
-  const FieldDef* FindFieldByName(const char* name) const {
-    return FindFieldByName(name, strlen(name));
-  }
-  FieldDef* FindFieldByName(const char* name) {
-    return FindFieldByName(name, strlen(name));
-  }
-
-  template <class T>
-  FieldDef* FindFieldByName(const T& str) {
-    return FindFieldByName(str.c_str(), str.size());
-  }
-  template <class T>
-  const FieldDef* FindFieldByName(const T& str) const {
-    return FindFieldByName(str.c_str(), str.size());
-  }
-
-  /* Looks up by tag number. */
-  const FieldDef* FindFieldByNumber(uint32_t num) const;
-
-  /* Iteration over fields.  The order is undefined. */
-  class iterator : public std::iterator<std::forward_iterator_tag, FieldDef*> {
+   * TODO: make compatible with range-for, with elements as pairs? */
+  class Iterator {
    public:
-    explicit iterator(OneofDef* md);
-    static iterator end(OneofDef* md);
+    explicit Iterator(EnumDefPtr e) { upb_enum_begin(&iter_, e.ptr()); }
 
-    void operator++();
-    FieldDef* operator*() const;
-    bool operator!=(const iterator& other) const;
-    bool operator==(const iterator& other) const;
+    int32_t number() { return upb_enum_iter_number(&iter_); }
+    const char *name() { return upb_enum_iter_name(&iter_); }
+    bool Done() { return upb_enum_done(&iter_); }
+    void Next() { return upb_enum_next(&iter_); }
 
    private:
-    upb_oneof_iter iter_;
+    upb_enum_iter iter_;
   };
 
-  class const_iterator
-      : public std::iterator<std::forward_iterator_tag, const FieldDef*> {
-   public:
-    explicit const_iterator(const OneofDef* md);
-    static const_iterator end(const OneofDef* md);
-
-    void operator++();
-    const FieldDef* operator*() const;
-    bool operator!=(const const_iterator& other) const;
-    bool operator==(const const_iterator& other) const;
-
-   private:
-    upb_oneof_iter iter_;
-  };
-
-  iterator begin();
-  iterator end();
-  const_iterator begin() const;
-  const_iterator end() const;
-
  private:
-  UPB_DISALLOW_POD_OPS(OneofDef, upb::OneofDef)
+  const upb_enumdef *ptr_;
 };
 
+inline upb::EnumDefPtr upb::FieldDefPtr::enum_subdef() const {
+  return EnumDefPtr(upb_fielddef_enumsubdef(ptr_));
+}
+
 #endif  /* __cplusplus */
 
-UPB_BEGIN_EXTERN_C
-
-/* Native C API. */
-upb_oneofdef *upb_oneofdef_new(const void *owner);
-
-/* Include upb_refcounted methods like upb_oneofdef_ref(). */
-UPB_REFCOUNTED_CMETHODS(upb_oneofdef, upb_oneofdef_upcast)
-
-const char *upb_oneofdef_name(const upb_oneofdef *o);
-const upb_msgdef *upb_oneofdef_containingtype(const upb_oneofdef *o);
-int upb_oneofdef_numfields(const upb_oneofdef *o);
-uint32_t upb_oneofdef_index(const upb_oneofdef *o);
-
-bool upb_oneofdef_setname(upb_oneofdef *o, const char *name, upb_status *s);
-bool upb_oneofdef_addfield(upb_oneofdef *o, upb_fielddef *f,
-                           const void *ref_donor,
-                           upb_status *s);
-
-/* Oneof lookups:
- * - ntof:  look up a field by name.
- * - ntofz: look up a field by name (as a null-terminated string).
- * - itof:  look up a field by number. */
-const upb_fielddef *upb_oneofdef_ntof(const upb_oneofdef *o,
-                                      const char *name, size_t length);
-UPB_INLINE const upb_fielddef *upb_oneofdef_ntofz(const upb_oneofdef *o,
-                                                  const char *name) {
-  return upb_oneofdef_ntof(o, name, strlen(name));
-}
-const upb_fielddef *upb_oneofdef_itof(const upb_oneofdef *o, uint32_t num);
-
-/*  upb_oneof_iter i;
- *  for(upb_oneof_begin(&i, e); !upb_oneof_done(&i); upb_oneof_next(&i)) {
- *    // ...
- *  }
- */
-void upb_oneof_begin(upb_oneof_iter *iter, const upb_oneofdef *o);
-void upb_oneof_next(upb_oneof_iter *iter);
-bool upb_oneof_done(upb_oneof_iter *iter);
-upb_fielddef *upb_oneof_iter_field(const upb_oneof_iter *iter);
-void upb_oneof_iter_setdone(upb_oneof_iter *iter);
-
-UPB_END_EXTERN_C
-
-
-/* upb::FileDef ***************************************************************/
+/* upb_filedef ****************************************************************/
 
 #ifdef __cplusplus
-
-/* Class that represents a .proto file with some things defined in it.
- *
- * Many users won't care about FileDefs, but they are necessary if you want to
- * read the values of file-level options. */
-class upb::FileDef {
- public:
-  /* Returns NULL if memory allocation failed. */
-  static reffed_ptr<FileDef> New();
-
-  /* upb::RefCounted methods like Ref()/Unref(). */
-  UPB_REFCOUNTED_CPPMETHODS
-
-  /* Get/set name of the file (eg. "foo/bar.proto"). */
-  const char* name() const;
-  bool set_name(const char* name, Status* s);
-  bool set_name(const std::string& name, Status* s);
-
-  /* Package name for definitions inside the file (eg. "foo.bar"). */
-  const char* package() const;
-  bool set_package(const char* package, Status* s);
-
-  /* Sets the php class prefix which is prepended to all php generated classes
-   * from this .proto. Default is empty. */
-  const char* phpprefix() const;
-  bool set_phpprefix(const char* phpprefix, Status* s);
-
-  /* Use this option to change the namespace of php generated classes. Default
-   * is empty. When this option is empty, the package name will be used for
-   * determining the namespace. */
-  const char* phpnamespace() const;
-  bool set_phpnamespace(const char* phpnamespace, Status* s);
-
-  /* Syntax for the file.  Defaults to proto2. */
-  upb_syntax_t syntax() const;
-  void set_syntax(upb_syntax_t syntax);
-
-  /* Get the list of defs from the file.  These are returned in the order that
-   * they were added to the FileDef. */
-  int def_count() const;
-  const Def* def(int index) const;
-  Def* def(int index);
-
-  /* Get the list of dependencies from the file.  These are returned in the
-   * order that they were added to the FileDef. */
-  int dependency_count() const;
-  const FileDef* dependency(int index) const;
-
-  /* Adds defs to this file.  The def must not already belong to another
-   * file.
-   *
-   * Note: this does *not* ensure that this def's name is unique in this file!
-   * Use a SymbolTable if you want to check this property.  Especially since
-   * properly checking uniqueness would require a check across *all* files
-   * (including dependencies). */
-  bool AddDef(Def* def, Status* s);
-  bool AddMessage(MessageDef* m, Status* s);
-  bool AddEnum(EnumDef* e, Status* s);
-  bool AddExtension(FieldDef* f, Status* s);
-
-  /* Adds a dependency of this file. */
-  bool AddDependency(const FileDef* file);
-
-  /* Freezes this FileDef and all messages/enums under it.  All subdefs must be
-   * resolved and all messages/enums must validate.  Returns true if this
-   * succeeded.
-   *
-   * TODO(haberman): should we care whether the file's dependencies are frozen
-   * already? */
-  bool Freeze(Status* s);
-
- private:
-  UPB_DISALLOW_POD_OPS(FileDef, upb::FileDef)
-};
-
+extern "C" {
 #endif
 
-UPB_BEGIN_EXTERN_C
-
-upb_filedef *upb_filedef_new(const void *owner);
-
-/* Include upb_refcounted methods like upb_msgdef_ref(). */
-UPB_REFCOUNTED_CMETHODS(upb_filedef, upb_filedef_upcast)
-
 const char *upb_filedef_name(const upb_filedef *f);
 const char *upb_filedef_package(const upb_filedef *f);
 const char *upb_filedef_phpprefix(const upb_filedef *f);
 const char *upb_filedef_phpnamespace(const upb_filedef *f);
 upb_syntax_t upb_filedef_syntax(const upb_filedef *f);
-size_t upb_filedef_defcount(const upb_filedef *f);
-size_t upb_filedef_depcount(const upb_filedef *f);
-const upb_def *upb_filedef_def(const upb_filedef *f, size_t i);
-const upb_filedef *upb_filedef_dep(const upb_filedef *f, size_t i);
-
-bool upb_filedef_freeze(upb_filedef *f, upb_status *s);
-bool upb_filedef_setname(upb_filedef *f, const char *name, upb_status *s);
-bool upb_filedef_setpackage(upb_filedef *f, const char *package, upb_status *s);
-bool upb_filedef_setphpprefix(upb_filedef *f, const char *phpprefix,
-                              upb_status *s);
-bool upb_filedef_setphpnamespace(upb_filedef *f, const char *phpnamespace,
-                                 upb_status *s);
-bool upb_filedef_setsyntax(upb_filedef *f, upb_syntax_t syntax, upb_status *s);
-
-bool upb_filedef_adddef(upb_filedef *f, upb_def *def, const void *ref_donor,
-                        upb_status *s);
-bool upb_filedef_adddep(upb_filedef *f, const upb_filedef *dep);
-
-UPB_INLINE bool upb_filedef_addmsg(upb_filedef *f, upb_msgdef *m,
-                                   const void *ref_donor, upb_status *s) {
-  return upb_filedef_adddef(f, upb_msgdef_upcast_mutable(m), ref_donor, s);
-}
-
-UPB_INLINE bool upb_filedef_addenum(upb_filedef *f, upb_enumdef *e,
-                                    const void *ref_donor, upb_status *s) {
-  return upb_filedef_adddef(f, upb_enumdef_upcast_mutable(e), ref_donor, s);
-}
-
-UPB_INLINE bool upb_filedef_addext(upb_filedef *file, upb_fielddef *f,
-                                   const void *ref_donor, upb_status *s) {
-  return upb_filedef_adddef(file, upb_fielddef_upcast_mutable(f), ref_donor, s);
-}
-UPB_INLINE upb_def *upb_filedef_mutabledef(upb_filedef *f, int i) {
-  return (upb_def*)upb_filedef_def(f, i);
-}
-
-UPB_END_EXTERN_C
-
-typedef struct {
- UPB_PRIVATE_FOR_CPP
-  upb_strtable_iter iter;
-  upb_deftype_t type;
-} upb_symtab_iter;
+int upb_filedef_depcount(const upb_filedef *f);
+int upb_filedef_msgcount(const upb_filedef *f);
+int upb_filedef_enumcount(const upb_filedef *f);
+const upb_filedef *upb_filedef_dep(const upb_filedef *f, int i);
+const upb_msgdef *upb_filedef_msg(const upb_filedef *f, int i);
+const upb_enumdef *upb_filedef_enum(const upb_filedef *f, int i);
 
 #ifdef __cplusplus
+}  /* extern "C" */
 
-/* Non-const methods in upb::SymbolTable are NOT thread-safe. */
-class upb::SymbolTable {
+/* Class that represents a .proto file with some things defined in it.
+ *
+ * Many users won't care about FileDefs, but they are necessary if you want to
+ * read the values of file-level options. */
+class upb::FileDefPtr {
  public:
-  /* Returns a new symbol table with a single ref owned by "owner."
-   * Returns NULL if memory allocation failed. */
-  static SymbolTable* New();
-  static void Free(upb::SymbolTable* table);
+  explicit FileDefPtr(const upb_filedef *ptr) : ptr_(ptr) {}
 
-  /* For all lookup functions, the returned pointer is not owned by the
-   * caller; it may be invalidated by any non-const call or unref of the
-   * SymbolTable!  To protect against this, take a ref if desired. */
+  const upb_filedef* ptr() const { return ptr_; }
+  explicit operator bool() const { return ptr_ != nullptr; }
 
-  /* Freezes the symbol table: prevents further modification of it.
-   * After the Freeze() operation is successful, the SymbolTable must only be
-   * accessed via a const pointer.
-   *
-   * Unlike with upb::MessageDef/upb::EnumDef/etc, freezing a SymbolTable is not
-   * a necessary step in using a SymbolTable.  If you have no need for it to be
-   * immutable, there is no need to freeze it ever.  However sometimes it is
-   * useful, and SymbolTables that are statically compiled into the binary are
-   * always frozen by nature. */
-  void Freeze();
+  /* Get/set name of the file (eg. "foo/bar.proto"). */
+  const char* name() const { return upb_filedef_name(ptr_); }
 
-  /* Resolves the given symbol using the rules described in descriptor.proto,
-   * namely:
-   *
-   *    If the name starts with a '.', it is fully-qualified.  Otherwise,
-   *    C++-like scoping rules are used to find the type (i.e. first the nested
-   *    types within this message are searched, then within the parent, on up
-   *    to the root namespace).
-   *
-   * If not found, returns NULL. */
-  const Def* Resolve(const char* base, const char* sym) const;
+  /* Package name for definitions inside the file (eg. "foo.bar"). */
+  const char* package() const { return upb_filedef_package(ptr_); }
 
-  /* Finds an entry in the symbol table with this exact name.  If not found,
-   * returns NULL. */
-  const Def* Lookup(const char *sym) const;
-  const MessageDef* LookupMessage(const char *sym) const;
-  const EnumDef* LookupEnum(const char *sym) const;
+  /* Sets the php class prefix which is prepended to all php generated classes
+   * from this .proto. Default is empty. */
+  const char* phpprefix() const { return upb_filedef_phpprefix(ptr_); }
 
-  /* TODO: introduce a C++ iterator, but make it nice and templated so that if
-   * you ask for an iterator of MessageDef the iterated elements are strongly
-   * typed as MessageDef*. */
+  /* Use this option to change the namespace of php generated classes. Default
+   * is empty. When this option is empty, the package name will be used for
+   * determining the namespace. */
+  const char* phpnamespace() const { return upb_filedef_phpnamespace(ptr_); }
 
-  /* Adds the given mutable defs to the symtab, resolving all symbols (including
-   * enum default values) and finalizing the defs.  Only one def per name may be
-   * in the list, and the defs may not duplicate any name already in the symtab.
-   * All defs must have a name -- anonymous defs are not allowed.  Anonymous
-   * defs can still be frozen by calling upb_def_freeze() directly.
-   *
-   * The entire operation either succeeds or fails.  If the operation fails,
-   * the symtab is unchanged, false is returned, and status indicates the
-   * error.  The caller passes a ref on all defs to the symtab (even if the
-   * operation fails).
-   *
-   * TODO(haberman): currently failure will leave the symtab unchanged, but may
-   * leave the defs themselves partially resolved.  Does this matter?  If so we
-   * could do a prepass that ensures that all symbols are resolvable and bail
-   * if not, so we don't mutate anything until we know the operation will
-   * succeed. */
-  bool Add(Def*const* defs, size_t n, void* ref_donor, Status* status);
+  /* Syntax for the file.  Defaults to proto2. */
+  upb_syntax_t syntax() const { return upb_filedef_syntax(ptr_); }
 
-  bool Add(const std::vector<Def*>& defs, void *owner, Status* status) {
-    return Add((Def*const*)&defs[0], defs.size(), owner, status);
+  /* Get the list of dependencies from the file.  These are returned in the
+   * order that they were added to the FileDefPtr. */
+  int dependency_count() const { return upb_filedef_depcount(ptr_); }
+  const FileDefPtr dependency(int index) const {
+    return FileDefPtr(upb_filedef_dep(ptr_, index));
   }
 
-  /* Resolves all subdefs for messages in this file and attempts to freeze the
-   * file.  If this succeeds, adds all the symbols to this SymbolTable
-   * (replacing any existing ones with the same names). */
-  bool AddFile(FileDef* file, Status* s);
-
  private:
-  UPB_DISALLOW_POD_OPS(SymbolTable, upb::SymbolTable)
+  const upb_filedef* ptr_;
 };
 
 #endif  /* __cplusplus */
 
-UPB_BEGIN_EXTERN_C
+/* upb_symtab *****************************************************************/
 
-/* Native C API. */
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 upb_symtab *upb_symtab_new();
 void upb_symtab_free(upb_symtab* s);
-const upb_def *upb_symtab_resolve(const upb_symtab *s, const char *base,
-                                  const char *sym);
-const upb_def *upb_symtab_lookup(const upb_symtab *s, const char *sym);
 const upb_msgdef *upb_symtab_lookupmsg(const upb_symtab *s, const char *sym);
 const upb_msgdef *upb_symtab_lookupmsg2(
     const upb_symtab *s, const char *sym, size_t len);
 const upb_enumdef *upb_symtab_lookupenum(const upb_symtab *s, const char *sym);
-bool upb_symtab_add(upb_symtab *s, upb_def *const*defs, size_t n,
-                    void *ref_donor, upb_status *status);
-bool upb_symtab_addfile(upb_symtab *s, upb_filedef *file, upb_status* status);
+const upb_filedef *upb_symtab_lookupfile(const upb_symtab *s, const char *name);
+int upb_symtab_filecount(const upb_symtab *s);
+const upb_filedef *upb_symtab_addfile(
+    upb_symtab *s, const google_protobuf_FileDescriptorProto *file,
+    upb_status *status);
 
-/* upb_symtab_iter i;
- * for(upb_symtab_begin(&i, s, type); !upb_symtab_done(&i);
- *     upb_symtab_next(&i)) {
- *   const upb_def *def = upb_symtab_iter_def(&i);
- *    // ...
- * }
- *
- * For C we don't have separate iterators for const and non-const.
- * It is the caller's responsibility to cast the upb_fielddef* to
- * const if the upb_msgdef* is const. */
-void upb_symtab_begin(upb_symtab_iter *iter, const upb_symtab *s,
-                      upb_deftype_t type);
-void upb_symtab_next(upb_symtab_iter *iter);
-bool upb_symtab_done(const upb_symtab_iter *iter);
-const upb_def *upb_symtab_iter_def(const upb_symtab_iter *iter);
+/* For generated code only: loads a generated descriptor. */
+typedef struct upb_def_init {
+  struct upb_def_init **deps;
+  const char *filename;
+  upb_strview descriptor;
+} upb_def_init;
 
-UPB_END_EXTERN_C
+bool _upb_symtab_loaddefinit(upb_symtab *s, const upb_def_init *init);
 
 #ifdef __cplusplus
-/* C++ inline wrappers. */
-namespace upb {
-inline SymbolTable* SymbolTable::New() {
-  return upb_symtab_new();
-}
-inline void SymbolTable::Free(SymbolTable* s) {
-  upb_symtab_free(s);
-}
-inline const Def *SymbolTable::Resolve(const char *base,
-                                       const char *sym) const {
-  return upb_symtab_resolve(this, base, sym);
-}
-inline const Def* SymbolTable::Lookup(const char *sym) const {
-  return upb_symtab_lookup(this, sym);
-}
-inline const MessageDef *SymbolTable::LookupMessage(const char *sym) const {
-  return upb_symtab_lookupmsg(this, sym);
-}
-inline bool SymbolTable::Add(
-    Def*const* defs, size_t n, void* ref_donor, Status* status) {
-  return upb_symtab_add(this, (upb_def*const*)defs, n, ref_donor, status);
-}
-inline bool SymbolTable::AddFile(FileDef* file, Status* s) {
-  return upb_symtab_addfile(this, file, s);
-}
-}  /* namespace upb */
-#endif
+}  /* extern "C" */
 
-#ifdef __cplusplus
+/* Non-const methods in upb::SymbolTable are NOT thread-safe. */
+class upb::SymbolTable {
+ public:
+  SymbolTable() : ptr_(upb_symtab_new(), upb_symtab_free) {}
+  explicit SymbolTable(upb_symtab* s) : ptr_(s, upb_symtab_free) {}
+
+  const upb_symtab* ptr() const { return ptr_.get(); }
+  upb_symtab* ptr() { return ptr_.get(); }
+
+  /* Finds an entry in the symbol table with this exact name.  If not found,
+   * returns NULL. */
+  MessageDefPtr LookupMessage(const char *sym) const {
+    return MessageDefPtr(upb_symtab_lookupmsg(ptr_.get(), sym));
+  }
+
+  EnumDefPtr LookupEnum(const char *sym) const {
+    return EnumDefPtr(upb_symtab_lookupenum(ptr_.get(), sym));
+  }
+
+  FileDefPtr LookupFile(const char *name) const {
+    return FileDefPtr(upb_symtab_lookupfile(ptr_.get(), name));
+  }
+
+  /* TODO: iteration? */
+
+  /* Adds the given serialized FileDescriptorProto to the pool. */
+  FileDefPtr AddFile(const google_protobuf_FileDescriptorProto *file_proto,
+                     Status *status) {
+    return FileDefPtr(
+        upb_symtab_addfile(ptr_.get(), file_proto, status->ptr()));
+  }
+
+ private:
+  std::unique_ptr<upb_symtab, decltype(&upb_symtab_free)> ptr_;
+};
 
 UPB_INLINE const char* upb_safecstr(const std::string& str) {
   UPB_ASSERT(str.size() == std::strlen(str.c_str()));
   return str.c_str();
 }
 
-/* Inline C++ wrappers. */
-namespace upb {
-
-inline Def::Type Def::def_type() const { return upb_def_type(this); }
-inline const char* Def::full_name() const { return upb_def_fullname(this); }
-inline const char* Def::name() const { return upb_def_name(this); }
-inline bool Def::set_full_name(const char* fullname, Status* s) {
-  return upb_def_setfullname(this, fullname, s);
-}
-inline bool Def::set_full_name(const std::string& fullname, Status* s) {
-  return upb_def_setfullname(this, upb_safecstr(fullname), s);
-}
-inline bool Def::Freeze(Def* const* defs, size_t n, Status* status) {
-  return upb_def_freeze(defs, n, status);
-}
-inline bool Def::Freeze(const std::vector<Def*>& defs, Status* status) {
-  return upb_def_freeze((Def* const*)&defs[0], defs.size(), status);
-}
-
-inline bool FieldDef::CheckType(int32_t val) {
-  return upb_fielddef_checktype(val);
-}
-inline bool FieldDef::CheckLabel(int32_t val) {
-  return upb_fielddef_checklabel(val);
-}
-inline bool FieldDef::CheckDescriptorType(int32_t val) {
-  return upb_fielddef_checkdescriptortype(val);
-}
-inline bool FieldDef::CheckIntegerFormat(int32_t val) {
-  return upb_fielddef_checkintfmt(val);
-}
-inline FieldDef::Type FieldDef::ConvertType(int32_t val) {
-  UPB_ASSERT(CheckType(val));
-  return static_cast<FieldDef::Type>(val);
-}
-inline FieldDef::Label FieldDef::ConvertLabel(int32_t val) {
-  UPB_ASSERT(CheckLabel(val));
-  return static_cast<FieldDef::Label>(val);
-}
-inline FieldDef::DescriptorType FieldDef::ConvertDescriptorType(int32_t val) {
-  UPB_ASSERT(CheckDescriptorType(val));
-  return static_cast<FieldDef::DescriptorType>(val);
-}
-inline FieldDef::IntegerFormat FieldDef::ConvertIntegerFormat(int32_t val) {
-  UPB_ASSERT(CheckIntegerFormat(val));
-  return static_cast<FieldDef::IntegerFormat>(val);
-}
-
-inline reffed_ptr<FieldDef> FieldDef::New() {
-  upb_fielddef *f = upb_fielddef_new(&f);
-  return reffed_ptr<FieldDef>(f, &f);
-}
-inline const char* FieldDef::full_name() const {
-  return upb_fielddef_fullname(this);
-}
-inline bool FieldDef::set_full_name(const char* fullname, Status* s) {
-  return upb_fielddef_setfullname(this, fullname, s);
-}
-inline bool FieldDef::set_full_name(const std::string& fullname, Status* s) {
-  return upb_fielddef_setfullname(this, upb_safecstr(fullname), s);
-}
-inline bool FieldDef::type_is_set() const {
-  return upb_fielddef_typeisset(this);
-}
-inline FieldDef::Type FieldDef::type() const { return upb_fielddef_type(this); }
-inline FieldDef::DescriptorType FieldDef::descriptor_type() const {
-  return upb_fielddef_descriptortype(this);
-}
-inline FieldDef::Label FieldDef::label() const {
-  return upb_fielddef_label(this);
-}
-inline uint32_t FieldDef::number() const { return upb_fielddef_number(this); }
-inline const char* FieldDef::name() const { return upb_fielddef_name(this); }
-inline bool FieldDef::is_extension() const {
-  return upb_fielddef_isextension(this);
-}
-inline size_t FieldDef::GetJsonName(char* buf, size_t len) const {
-  return upb_fielddef_getjsonname(this, buf, len);
-}
-inline bool FieldDef::lazy() const {
-  return upb_fielddef_lazy(this);
-}
-inline void FieldDef::set_lazy(bool lazy) {
-  upb_fielddef_setlazy(this, lazy);
-}
-inline bool FieldDef::packed() const {
-  return upb_fielddef_packed(this);
-}
-inline uint32_t FieldDef::index() const {
-  return upb_fielddef_index(this);
-}
-inline void FieldDef::set_packed(bool packed) {
-  upb_fielddef_setpacked(this, packed);
-}
-inline const MessageDef* FieldDef::containing_type() const {
-  return upb_fielddef_containingtype(this);
-}
-inline const OneofDef* FieldDef::containing_oneof() const {
-  return upb_fielddef_containingoneof(this);
-}
-inline const char* FieldDef::containing_type_name() {
-  return upb_fielddef_containingtypename(this);
-}
-inline bool FieldDef::set_number(uint32_t number, Status* s) {
-  return upb_fielddef_setnumber(this, number, s);
-}
-inline bool FieldDef::set_name(const char *name, Status* s) {
-  return upb_fielddef_setname(this, name, s);
-}
-inline bool FieldDef::set_name(const std::string& name, Status* s) {
-  return upb_fielddef_setname(this, upb_safecstr(name), s);
-}
-inline bool FieldDef::set_json_name(const char *name, Status* s) {
-  return upb_fielddef_setjsonname(this, name, s);
-}
-inline bool FieldDef::set_json_name(const std::string& name, Status* s) {
-  return upb_fielddef_setjsonname(this, upb_safecstr(name), s);
-}
-inline void FieldDef::clear_json_name() {
-  upb_fielddef_clearjsonname(this);
-}
-inline bool FieldDef::set_containing_type_name(const char *name, Status* s) {
-  return upb_fielddef_setcontainingtypename(this, name, s);
-}
-inline bool FieldDef::set_containing_type_name(const std::string &name,
-                                               Status *s) {
-  return upb_fielddef_setcontainingtypename(this, upb_safecstr(name), s);
-}
-inline void FieldDef::set_type(upb_fieldtype_t type) {
-  upb_fielddef_settype(this, type);
-}
-inline void FieldDef::set_is_extension(bool is_extension) {
-  upb_fielddef_setisextension(this, is_extension);
-}
-inline void FieldDef::set_descriptor_type(FieldDef::DescriptorType type) {
-  upb_fielddef_setdescriptortype(this, type);
-}
-inline void FieldDef::set_label(upb_label_t label) {
-  upb_fielddef_setlabel(this, label);
-}
-inline bool FieldDef::IsSubMessage() const {
-  return upb_fielddef_issubmsg(this);
-}
-inline bool FieldDef::IsString() const { return upb_fielddef_isstring(this); }
-inline bool FieldDef::IsSequence() const { return upb_fielddef_isseq(this); }
-inline bool FieldDef::IsMap() const { return upb_fielddef_ismap(this); }
-inline int64_t FieldDef::default_int64() const {
-  return upb_fielddef_defaultint64(this);
-}
-inline int32_t FieldDef::default_int32() const {
-  return upb_fielddef_defaultint32(this);
-}
-inline uint64_t FieldDef::default_uint64() const {
-  return upb_fielddef_defaultuint64(this);
-}
-inline uint32_t FieldDef::default_uint32() const {
-  return upb_fielddef_defaultuint32(this);
-}
-inline bool FieldDef::default_bool() const {
-  return upb_fielddef_defaultbool(this);
-}
-inline float FieldDef::default_float() const {
-  return upb_fielddef_defaultfloat(this);
-}
-inline double FieldDef::default_double() const {
-  return upb_fielddef_defaultdouble(this);
-}
-inline const char* FieldDef::default_string(size_t* len) const {
-  return upb_fielddef_defaultstr(this, len);
-}
-inline void FieldDef::set_default_int64(int64_t value) {
-  upb_fielddef_setdefaultint64(this, value);
-}
-inline void FieldDef::set_default_int32(int32_t value) {
-  upb_fielddef_setdefaultint32(this, value);
-}
-inline void FieldDef::set_default_uint64(uint64_t value) {
-  upb_fielddef_setdefaultuint64(this, value);
-}
-inline void FieldDef::set_default_uint32(uint32_t value) {
-  upb_fielddef_setdefaultuint32(this, value);
-}
-inline void FieldDef::set_default_bool(bool value) {
-  upb_fielddef_setdefaultbool(this, value);
-}
-inline void FieldDef::set_default_float(float value) {
-  upb_fielddef_setdefaultfloat(this, value);
-}
-inline void FieldDef::set_default_double(double value) {
-  upb_fielddef_setdefaultdouble(this, value);
-}
-inline bool FieldDef::set_default_string(const void *str, size_t len,
-                                         Status *s) {
-  return upb_fielddef_setdefaultstr(this, str, len, s);
-}
-inline bool FieldDef::set_default_string(const std::string& str, Status* s) {
-  return upb_fielddef_setdefaultstr(this, str.c_str(), str.size(), s);
-}
-inline void FieldDef::set_default_cstr(const char* str, Status* s) {
-  return upb_fielddef_setdefaultcstr(this, str, s);
-}
-inline bool FieldDef::HasSubDef() const { return upb_fielddef_hassubdef(this); }
-inline const Def* FieldDef::subdef() const { return upb_fielddef_subdef(this); }
-inline const MessageDef *FieldDef::message_subdef() const {
-  return upb_fielddef_msgsubdef(this);
-}
-inline const EnumDef *FieldDef::enum_subdef() const {
-  return upb_fielddef_enumsubdef(this);
-}
-inline const char* FieldDef::subdef_name() const {
-  return upb_fielddef_subdefname(this);
-}
-inline bool FieldDef::set_subdef(const Def* subdef, Status* s) {
-  return upb_fielddef_setsubdef(this, subdef, s);
-}
-inline bool FieldDef::set_enum_subdef(const EnumDef* subdef, Status* s) {
-  return upb_fielddef_setenumsubdef(this, subdef, s);
-}
-inline bool FieldDef::set_message_subdef(const MessageDef* subdef, Status* s) {
-  return upb_fielddef_setmsgsubdef(this, subdef, s);
-}
-inline bool FieldDef::set_subdef_name(const char* name, Status* s) {
-  return upb_fielddef_setsubdefname(this, name, s);
-}
-inline bool FieldDef::set_subdef_name(const std::string& name, Status* s) {
-  return upb_fielddef_setsubdefname(this, upb_safecstr(name), s);
-}
-
-inline reffed_ptr<MessageDef> MessageDef::New() {
-  upb_msgdef *m = upb_msgdef_new(&m);
-  return reffed_ptr<MessageDef>(m, &m);
-}
-inline const char *MessageDef::full_name() const {
-  return upb_msgdef_fullname(this);
-}
-inline const char *MessageDef::name() const {
-  return upb_msgdef_name(this);
-}
-inline upb_syntax_t MessageDef::syntax() const {
-  return upb_msgdef_syntax(this);
-}
-inline bool MessageDef::set_full_name(const char* fullname, Status* s) {
-  return upb_msgdef_setfullname(this, fullname, s);
-}
-inline bool MessageDef::set_full_name(const std::string& fullname, Status* s) {
-  return upb_msgdef_setfullname(this, upb_safecstr(fullname), s);
-}
-inline bool MessageDef::set_syntax(upb_syntax_t syntax) {
-  return upb_msgdef_setsyntax(this, syntax);
-}
-inline bool MessageDef::Freeze(Status* status) {
-  return upb_msgdef_freeze(this, status);
-}
-inline int MessageDef::field_count() const {
-  return upb_msgdef_numfields(this);
-}
-inline int MessageDef::oneof_count() const {
-  return upb_msgdef_numoneofs(this);
-}
-inline bool MessageDef::AddField(upb_fielddef* f, Status* s) {
-  return upb_msgdef_addfield(this, f, NULL, s);
-}
-inline bool MessageDef::AddField(const reffed_ptr<FieldDef>& f, Status* s) {
-  return upb_msgdef_addfield(this, f.get(), NULL, s);
-}
-inline bool MessageDef::AddOneof(upb_oneofdef* o, Status* s) {
-  return upb_msgdef_addoneof(this, o, NULL, s);
-}
-inline bool MessageDef::AddOneof(const reffed_ptr<OneofDef>& o, Status* s) {
-  return upb_msgdef_addoneof(this, o.get(), NULL, s);
-}
-inline FieldDef* MessageDef::FindFieldByNumber(uint32_t number) {
-  return upb_msgdef_itof_mutable(this, number);
-}
-inline FieldDef* MessageDef::FindFieldByName(const char* name, size_t len) {
-  return upb_msgdef_ntof_mutable(this, name, len);
-}
-inline const FieldDef* MessageDef::FindFieldByNumber(uint32_t number) const {
-  return upb_msgdef_itof(this, number);
-}
-inline const FieldDef *MessageDef::FindFieldByName(const char *name,
-                                                   size_t len) const {
-  return upb_msgdef_ntof(this, name, len);
-}
-inline OneofDef* MessageDef::FindOneofByName(const char* name, size_t len) {
-  return upb_msgdef_ntoo_mutable(this, name, len);
-}
-inline const OneofDef* MessageDef::FindOneofByName(const char* name,
-                                                   size_t len) const {
-  return upb_msgdef_ntoo(this, name, len);
-}
-inline void MessageDef::setmapentry(bool map_entry) {
-  upb_msgdef_setmapentry(this, map_entry);
-}
-inline bool MessageDef::mapentry() const {
-  return upb_msgdef_mapentry(this);
-}
-inline upb_wellknowntype_t MessageDef::wellknowntype() const {
-  return upb_msgdef_wellknowntype(this);
-}
-inline bool MessageDef::isnumberwrapper() const {
-  return upb_msgdef_isnumberwrapper(this);
-}
-inline MessageDef::field_iterator MessageDef::field_begin() {
-  return field_iterator(this);
-}
-inline MessageDef::field_iterator MessageDef::field_end() {
-  return field_iterator::end(this);
-}
-inline MessageDef::const_field_iterator MessageDef::field_begin() const {
-  return const_field_iterator(this);
-}
-inline MessageDef::const_field_iterator MessageDef::field_end() const {
-  return const_field_iterator::end(this);
-}
-
-inline MessageDef::oneof_iterator MessageDef::oneof_begin() {
-  return oneof_iterator(this);
-}
-inline MessageDef::oneof_iterator MessageDef::oneof_end() {
-  return oneof_iterator::end(this);
-}
-inline MessageDef::const_oneof_iterator MessageDef::oneof_begin() const {
-  return const_oneof_iterator(this);
-}
-inline MessageDef::const_oneof_iterator MessageDef::oneof_end() const {
-  return const_oneof_iterator::end(this);
-}
-
-inline MessageDef::field_iterator::field_iterator(MessageDef* md) {
-  upb_msg_field_begin(&iter_, md);
-}
-inline MessageDef::field_iterator MessageDef::field_iterator::end(
-    MessageDef* md) {
-  MessageDef::field_iterator iter(md);
-  upb_msg_field_iter_setdone(&iter.iter_);
-  return iter;
-}
-inline FieldDef* MessageDef::field_iterator::operator*() const {
-  return upb_msg_iter_field(&iter_);
-}
-inline void MessageDef::field_iterator::operator++() {
-  return upb_msg_field_next(&iter_);
-}
-inline bool MessageDef::field_iterator::operator==(
-    const field_iterator &other) const {
-  return upb_inttable_iter_isequal(&iter_, &other.iter_);
-}
-inline bool MessageDef::field_iterator::operator!=(
-    const field_iterator &other) const {
-  return !(*this == other);
-}
-
-inline MessageDef::const_field_iterator::const_field_iterator(
-    const MessageDef* md) {
-  upb_msg_field_begin(&iter_, md);
-}
-inline MessageDef::const_field_iterator MessageDef::const_field_iterator::end(
-    const MessageDef *md) {
-  MessageDef::const_field_iterator iter(md);
-  upb_msg_field_iter_setdone(&iter.iter_);
-  return iter;
-}
-inline const FieldDef* MessageDef::const_field_iterator::operator*() const {
-  return upb_msg_iter_field(&iter_);
-}
-inline void MessageDef::const_field_iterator::operator++() {
-  return upb_msg_field_next(&iter_);
-}
-inline bool MessageDef::const_field_iterator::operator==(
-    const const_field_iterator &other) const {
-  return upb_inttable_iter_isequal(&iter_, &other.iter_);
-}
-inline bool MessageDef::const_field_iterator::operator!=(
-    const const_field_iterator &other) const {
-  return !(*this == other);
-}
-
-inline MessageDef::oneof_iterator::oneof_iterator(MessageDef* md) {
-  upb_msg_oneof_begin(&iter_, md);
-}
-inline MessageDef::oneof_iterator MessageDef::oneof_iterator::end(
-    MessageDef* md) {
-  MessageDef::oneof_iterator iter(md);
-  upb_msg_oneof_iter_setdone(&iter.iter_);
-  return iter;
-}
-inline OneofDef* MessageDef::oneof_iterator::operator*() const {
-  return upb_msg_iter_oneof(&iter_);
-}
-inline void MessageDef::oneof_iterator::operator++() {
-  return upb_msg_oneof_next(&iter_);
-}
-inline bool MessageDef::oneof_iterator::operator==(
-    const oneof_iterator &other) const {
-  return upb_strtable_iter_isequal(&iter_, &other.iter_);
-}
-inline bool MessageDef::oneof_iterator::operator!=(
-    const oneof_iterator &other) const {
-  return !(*this == other);
-}
-
-inline MessageDef::const_oneof_iterator::const_oneof_iterator(
-    const MessageDef* md) {
-  upb_msg_oneof_begin(&iter_, md);
-}
-inline MessageDef::const_oneof_iterator MessageDef::const_oneof_iterator::end(
-    const MessageDef *md) {
-  MessageDef::const_oneof_iterator iter(md);
-  upb_msg_oneof_iter_setdone(&iter.iter_);
-  return iter;
-}
-inline const OneofDef* MessageDef::const_oneof_iterator::operator*() const {
-  return upb_msg_iter_oneof(&iter_);
-}
-inline void MessageDef::const_oneof_iterator::operator++() {
-  return upb_msg_oneof_next(&iter_);
-}
-inline bool MessageDef::const_oneof_iterator::operator==(
-    const const_oneof_iterator &other) const {
-  return upb_strtable_iter_isequal(&iter_, &other.iter_);
-}
-inline bool MessageDef::const_oneof_iterator::operator!=(
-    const const_oneof_iterator &other) const {
-  return !(*this == other);
-}
-
-inline reffed_ptr<EnumDef> EnumDef::New() {
-  upb_enumdef *e = upb_enumdef_new(&e);
-  return reffed_ptr<EnumDef>(e, &e);
-}
-inline const char* EnumDef::full_name() const {
-  return upb_enumdef_fullname(this);
-}
-inline const char* EnumDef::name() const {
-  return upb_enumdef_name(this);
-}
-inline bool EnumDef::set_full_name(const char* fullname, Status* s) {
-  return upb_enumdef_setfullname(this, fullname, s);
-}
-inline bool EnumDef::set_full_name(const std::string& fullname, Status* s) {
-  return upb_enumdef_setfullname(this, upb_safecstr(fullname), s);
-}
-inline bool EnumDef::Freeze(Status* status) {
-  return upb_enumdef_freeze(this, status);
-}
-inline int32_t EnumDef::default_value() const {
-  return upb_enumdef_default(this);
-}
-inline bool EnumDef::set_default_value(int32_t val, Status* status) {
-  return upb_enumdef_setdefault(this, val, status);
-}
-inline int EnumDef::value_count() const { return upb_enumdef_numvals(this); }
-inline bool EnumDef::AddValue(const char* name, int32_t num, Status* status) {
-  return upb_enumdef_addval(this, name, num, status);
-}
-inline bool EnumDef::AddValue(const std::string& name, int32_t num,
-                              Status* status) {
-  return upb_enumdef_addval(this, upb_safecstr(name), num, status);
-}
-inline bool EnumDef::FindValueByName(const char* name, int32_t *num) const {
-  return upb_enumdef_ntoiz(this, name, num);
-}
-inline const char* EnumDef::FindValueByNumber(int32_t num) const {
-  return upb_enumdef_iton(this, num);
-}
-
-inline EnumDef::Iterator::Iterator(const EnumDef* e) {
-  upb_enum_begin(&iter_, e);
-}
-inline int32_t EnumDef::Iterator::number() {
-  return upb_enum_iter_number(&iter_);
-}
-inline const char* EnumDef::Iterator::name() {
-  return upb_enum_iter_name(&iter_);
-}
-inline bool EnumDef::Iterator::Done() { return upb_enum_done(&iter_); }
-inline void EnumDef::Iterator::Next() { return upb_enum_next(&iter_); }
-
-inline reffed_ptr<OneofDef> OneofDef::New() {
-  upb_oneofdef *o = upb_oneofdef_new(&o);
-  return reffed_ptr<OneofDef>(o, &o);
-}
-
-inline const MessageDef* OneofDef::containing_type() const {
-  return upb_oneofdef_containingtype(this);
-}
-inline const char* OneofDef::name() const {
-  return upb_oneofdef_name(this);
-}
-inline bool OneofDef::set_name(const char* name, Status* s) {
-  return upb_oneofdef_setname(this, name, s);
-}
-inline bool OneofDef::set_name(const std::string& name, Status* s) {
-  return upb_oneofdef_setname(this, upb_safecstr(name), s);
-}
-inline int OneofDef::field_count() const {
-  return upb_oneofdef_numfields(this);
-}
-inline bool OneofDef::AddField(FieldDef* field, Status* s) {
-  return upb_oneofdef_addfield(this, field, NULL, s);
-}
-inline bool OneofDef::AddField(const reffed_ptr<FieldDef>& field, Status* s) {
-  return upb_oneofdef_addfield(this, field.get(), NULL, s);
-}
-inline const FieldDef* OneofDef::FindFieldByName(const char* name,
-                                                 size_t len) const {
-  return upb_oneofdef_ntof(this, name, len);
-}
-inline const FieldDef* OneofDef::FindFieldByNumber(uint32_t num) const {
-  return upb_oneofdef_itof(this, num);
-}
-inline OneofDef::iterator OneofDef::begin() { return iterator(this); }
-inline OneofDef::iterator OneofDef::end() { return iterator::end(this); }
-inline OneofDef::const_iterator OneofDef::begin() const {
-  return const_iterator(this);
-}
-inline OneofDef::const_iterator OneofDef::end() const {
-  return const_iterator::end(this);
-}
-
-inline OneofDef::iterator::iterator(OneofDef* o) {
-  upb_oneof_begin(&iter_, o);
-}
-inline OneofDef::iterator OneofDef::iterator::end(OneofDef* o) {
-  OneofDef::iterator iter(o);
-  upb_oneof_iter_setdone(&iter.iter_);
-  return iter;
-}
-inline FieldDef* OneofDef::iterator::operator*() const {
-  return upb_oneof_iter_field(&iter_);
-}
-inline void OneofDef::iterator::operator++() { return upb_oneof_next(&iter_); }
-inline bool OneofDef::iterator::operator==(const iterator &other) const {
-  return upb_inttable_iter_isequal(&iter_, &other.iter_);
-}
-inline bool OneofDef::iterator::operator!=(const iterator &other) const {
-  return !(*this == other);
-}
-
-inline OneofDef::const_iterator::const_iterator(const OneofDef* md) {
-  upb_oneof_begin(&iter_, md);
-}
-inline OneofDef::const_iterator OneofDef::const_iterator::end(
-    const OneofDef *md) {
-  OneofDef::const_iterator iter(md);
-  upb_oneof_iter_setdone(&iter.iter_);
-  return iter;
-}
-inline const FieldDef* OneofDef::const_iterator::operator*() const {
-  return upb_msg_iter_field(&iter_);
-}
-inline void OneofDef::const_iterator::operator++() {
-  return upb_oneof_next(&iter_);
-}
-inline bool OneofDef::const_iterator::operator==(
-    const const_iterator &other) const {
-  return upb_inttable_iter_isequal(&iter_, &other.iter_);
-}
-inline bool OneofDef::const_iterator::operator!=(
-    const const_iterator &other) const {
-  return !(*this == other);
-}
-
-inline reffed_ptr<FileDef> FileDef::New() {
-  upb_filedef *f = upb_filedef_new(&f);
-  return reffed_ptr<FileDef>(f, &f);
-}
-
-inline const char* FileDef::name() const {
-  return upb_filedef_name(this);
-}
-inline bool FileDef::set_name(const char* name, Status* s) {
-  return upb_filedef_setname(this, name, s);
-}
-inline bool FileDef::set_name(const std::string& name, Status* s) {
-  return upb_filedef_setname(this, upb_safecstr(name), s);
-}
-inline const char* FileDef::package() const {
-  return upb_filedef_package(this);
-}
-inline bool FileDef::set_package(const char* package, Status* s) {
-  return upb_filedef_setpackage(this, package, s);
-}
-inline const char* FileDef::phpprefix() const {
-  return upb_filedef_phpprefix(this);
-}
-inline bool FileDef::set_phpprefix(const char* phpprefix, Status* s) {
-  return upb_filedef_setphpprefix(this, phpprefix, s);
-}
-inline const char* FileDef::phpnamespace() const {
-  return upb_filedef_phpnamespace(this);
-}
-inline bool FileDef::set_phpnamespace(const char* phpnamespace, Status* s) {
-  return upb_filedef_setphpnamespace(this, phpnamespace, s);
-}
-inline int FileDef::def_count() const {
-  return upb_filedef_defcount(this);
-}
-inline const Def* FileDef::def(int index) const {
-  return upb_filedef_def(this, index);
-}
-inline Def* FileDef::def(int index) {
-  return const_cast<Def*>(upb_filedef_def(this, index));
-}
-inline int FileDef::dependency_count() const {
-  return upb_filedef_depcount(this);
-}
-inline const FileDef* FileDef::dependency(int index) const {
-  return upb_filedef_dep(this, index);
-}
-inline bool FileDef::AddDef(Def* def, Status* s) {
-  return upb_filedef_adddef(this, def, NULL, s);
-}
-inline bool FileDef::AddMessage(MessageDef* m, Status* s) {
-  return upb_filedef_addmsg(this, m, NULL, s);
-}
-inline bool FileDef::AddEnum(EnumDef* e, Status* s) {
-  return upb_filedef_addenum(this, e, NULL, s);
-}
-inline bool FileDef::AddExtension(FieldDef* f, Status* s) {
-  return upb_filedef_addext(this, f, NULL, s);
-}
-inline bool FileDef::AddDependency(const FileDef* file) {
-  return upb_filedef_adddep(this, file);
-}
-
-}  /* namespace upb */
-#endif
+#endif  /* __cplusplus */
 
 #endif /* UPB_DEF_H_ */
 /*
@@ -3987,20 +3977,13 @@
 
 #ifdef __cplusplus
 namespace upb {
-class BufferHandle;
-class BytesHandler;
-class HandlerAttributes;
-class Handlers;
+class HandlersPtr;
+class HandlerCache;
 template <class T> class Handler;
 template <class T> struct CanonicalType;
 }  /* namespace upb */
 #endif
 
-UPB_DECLARE_TYPE(upb::BufferHandle, upb_bufhandle)
-UPB_DECLARE_TYPE(upb::BytesHandler, upb_byteshandler)
-UPB_DECLARE_TYPE(upb::HandlerAttributes, upb_handlerattr)
-UPB_DECLARE_DERIVED_TYPE(upb::Handlers, upb::RefCounted,
-                         upb_handlers, upb_refcounted)
 
 /* The maximum depth that the handler graph can have.  This is a resource limit
  * for the C stack since we sometimes need to recursively traverse the graph.
@@ -4042,28 +4025,6 @@
  * (for example: the STARTSUBMSG handler for field "field15"). */
 typedef int32_t upb_selector_t;
 
-UPB_BEGIN_EXTERN_C
-
-/* Forward-declares for C inline accessors.  We need to declare these here
- * so we can "friend" them in the class declarations in C++. */
-UPB_INLINE upb_func *upb_handlers_gethandler(const upb_handlers *h,
-                                             upb_selector_t s);
-UPB_INLINE const void *upb_handlerattr_handlerdata(const upb_handlerattr *attr);
-UPB_INLINE const void *upb_handlers_gethandlerdata(const upb_handlers *h,
-                                                   upb_selector_t s);
-
-UPB_INLINE void upb_bufhandle_init(upb_bufhandle *h);
-UPB_INLINE void upb_bufhandle_setobj(upb_bufhandle *h, const void *obj,
-                                     const void *type);
-UPB_INLINE void upb_bufhandle_setbuf(upb_bufhandle *h, const char *buf,
-                                     size_t ofs);
-UPB_INLINE const void *upb_bufhandle_obj(const upb_bufhandle *h);
-UPB_INLINE const void *upb_bufhandle_objtype(const upb_bufhandle *h);
-UPB_INLINE const char *upb_bufhandle_buf(const upb_bufhandle *h);
-
-UPB_END_EXTERN_C
-
-
 /* Static selectors for upb::Handlers. */
 #define UPB_STARTMSG_SELECTOR 0
 #define UPB_ENDMSG_SELECTOR 1
@@ -4075,125 +4036,236 @@
 #define UPB_STRING_SELECTOR 1
 #define UPB_ENDSTR_SELECTOR 2
 
-typedef void upb_handlerfree(void *d);
-
 #ifdef __cplusplus
-
-/* A set of attributes that accompanies a handler's function pointer. */
-class upb::HandlerAttributes {
- public:
-  HandlerAttributes();
-  ~HandlerAttributes();
-
-  /* Sets the handler data that will be passed as the second parameter of the
-   * handler.  To free this pointer when the handlers are freed, call
-   * Handlers::AddCleanup(). */
-  bool SetHandlerData(const void *handler_data);
-  const void* handler_data() const;
-
-  /* Use this to specify the type of the closure.  This will be checked against
-   * all other closure types for handler that use the same closure.
-   * Registration will fail if this does not match all other non-NULL closure
-   * types. */
-  bool SetClosureType(const void *closure_type);
-  const void* closure_type() const;
-
-  /* Use this to specify the type of the returned closure.  Only used for
-   * Start*{String,SubMessage,Sequence} handlers.  This must match the closure
-   * type of any handlers that use it (for example, the StringBuf handler must
-   * match the closure returned from StartString). */
-  bool SetReturnClosureType(const void *return_closure_type);
-  const void* return_closure_type() const;
-
-  /* Set to indicate that the handler always returns "ok" (either "true" or a
-   * non-NULL closure).  This is a hint that can allow code generators to
-   * generate more efficient code. */
-  bool SetAlwaysOk(bool always_ok);
-  bool always_ok() const;
-
- private:
-  friend UPB_INLINE const void * ::upb_handlerattr_handlerdata(
-      const upb_handlerattr *attr);
-#else
-struct upb_handlerattr {
+template<class T> const void *UniquePtrForType() {
+  static const char ch = 0;
+  return &ch;
+}
 #endif
-  const void *handler_data_;
-  const void *closure_type_;
-  const void *return_closure_type_;
-  bool alwaysok_;
-};
 
-#define UPB_HANDLERATTR_INITIALIZER {NULL, NULL, NULL, false}
+/* upb_handlers ************************************************************/
 
+/* Handler attributes, to be registered with the handler itself. */
 typedef struct {
-  upb_func *func;
+  const void *handler_data;
+  const void *closure_type;
+  const void *return_closure_type;
+  bool alwaysok;
+} upb_handlerattr;
 
-  /* It is wasteful to include the entire attributes here:
-   *
-   * * Some of the information is redundant (like storing the closure type
-   *   separately for each handler that must match).
-   * * Some of the info is only needed prior to freeze() (like closure types).
-   * * alignment padding wastes a lot of space for alwaysok_.
-   *
-   * If/when the size and locality of handlers is an issue, we can optimize this
-   * not to store the entire attr like this.  We do not expose the table's
-   * layout to allow this optimization in the future. */
-  upb_handlerattr attr;
-} upb_handlers_tabent;
+#define UPB_HANDLERATTR_INIT {NULL, NULL, NULL, false}
 
-#ifdef __cplusplus
-
-/* Extra information about a buffer that is passed to a StringBuf handler.
- * TODO(haberman): allow the handle to be pinned so that it will outlive
- * the handler invocation. */
-class upb::BufferHandle {
- public:
-  BufferHandle();
-  ~BufferHandle();
-
+/* Bufhandle, data passed along with a buffer to indicate its provenance. */
+typedef struct {
   /* The beginning of the buffer.  This may be different than the pointer
    * passed to a StringBuf handler because the handler may receive data
    * that is from the middle or end of a larger buffer. */
-  const char* buffer() const;
+  const char *buf;
 
   /* The offset within the attached object where this buffer begins.  Only
    * meaningful if there is an attached object. */
-  size_t object_offset() const;
+  size_t objofs;
 
-  /* Note that object_offset is the offset of "buf" within the attached
-   * object. */
-  void SetBuffer(const char* buf, size_t object_offset);
-
-  /* The BufferHandle can have an "attached object", which can be used to
-   * tunnel through a pointer to the buffer's underlying representation. */
-  template <class T>
-  void SetAttachedObject(const T* obj);
-
-  /* Returns NULL if the attached object is not of this type. */
-  template <class T>
-  const T* GetAttachedObject() const;
-
- private:
-  friend UPB_INLINE void ::upb_bufhandle_init(upb_bufhandle *h);
-  friend UPB_INLINE void ::upb_bufhandle_setobj(upb_bufhandle *h,
-                                                const void *obj,
-                                                const void *type);
-  friend UPB_INLINE void ::upb_bufhandle_setbuf(upb_bufhandle *h,
-                                                const char *buf, size_t ofs);
-  friend UPB_INLINE const void* ::upb_bufhandle_obj(const upb_bufhandle *h);
-  friend UPB_INLINE const void* ::upb_bufhandle_objtype(
-      const upb_bufhandle *h);
-  friend UPB_INLINE const char* ::upb_bufhandle_buf(const upb_bufhandle *h);
-#else
-struct upb_bufhandle {
-#endif
-  const char *buf_;
-  const void *obj_;
-  const void *objtype_;
-  size_t objofs_;
-};
+  /* The attached object (if any) and a pointer representing its type. */
+  const void *obj;
+  const void *objtype;
 
 #ifdef __cplusplus
+  template <class T>
+  void SetAttachedObject(const T* _obj) {
+    obj = _obj;
+    objtype = UniquePtrForType<T>();
+  }
+
+  template <class T>
+  const T *GetAttachedObject() const {
+    return objtype == UniquePtrForType<T>() ? static_cast<const T *>(obj)
+                                            : NULL;
+  }
+#endif
+} upb_bufhandle;
+
+#define UPB_BUFHANDLE_INIT {NULL, 0, NULL, NULL}
+
+/* Handler function typedefs. */
+typedef void upb_handlerfree(void *d);
+typedef bool upb_unknown_handlerfunc(void *c, const void *hd, const char *buf,
+                                     size_t n);
+typedef bool upb_startmsg_handlerfunc(void *c, const void*);
+typedef bool upb_endmsg_handlerfunc(void *c, const void *, upb_status *status);
+typedef void* upb_startfield_handlerfunc(void *c, const void *hd);
+typedef bool upb_endfield_handlerfunc(void *c, const void *hd);
+typedef bool upb_int32_handlerfunc(void *c, const void *hd, int32_t val);
+typedef bool upb_int64_handlerfunc(void *c, const void *hd, int64_t val);
+typedef bool upb_uint32_handlerfunc(void *c, const void *hd, uint32_t val);
+typedef bool upb_uint64_handlerfunc(void *c, const void *hd, uint64_t val);
+typedef bool upb_float_handlerfunc(void *c, const void *hd, float val);
+typedef bool upb_double_handlerfunc(void *c, const void *hd, double val);
+typedef bool upb_bool_handlerfunc(void *c, const void *hd, bool val);
+typedef void *upb_startstr_handlerfunc(void *c, const void *hd,
+                                       size_t size_hint);
+typedef size_t upb_string_handlerfunc(void *c, const void *hd, const char *buf,
+                                      size_t n, const upb_bufhandle* handle);
+
+struct upb_handlers;
+typedef struct upb_handlers upb_handlers;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Mutating accessors. */
+const upb_status *upb_handlers_status(upb_handlers *h);
+void upb_handlers_clearerr(upb_handlers *h);
+const upb_msgdef *upb_handlers_msgdef(const upb_handlers *h);
+bool upb_handlers_addcleanup(upb_handlers *h, void *p, upb_handlerfree *hfree);
+bool upb_handlers_setunknown(upb_handlers *h, upb_unknown_handlerfunc *func,
+                             const upb_handlerattr *attr);
+bool upb_handlers_setstartmsg(upb_handlers *h, upb_startmsg_handlerfunc *func,
+                              const upb_handlerattr *attr);
+bool upb_handlers_setendmsg(upb_handlers *h, upb_endmsg_handlerfunc *func,
+                            const upb_handlerattr *attr);
+bool upb_handlers_setint32(upb_handlers *h, const upb_fielddef *f,
+                           upb_int32_handlerfunc *func,
+                           const upb_handlerattr *attr);
+bool upb_handlers_setint64(upb_handlers *h, const upb_fielddef *f,
+                           upb_int64_handlerfunc *func,
+                           const upb_handlerattr *attr);
+bool upb_handlers_setuint32(upb_handlers *h, const upb_fielddef *f,
+                            upb_uint32_handlerfunc *func,
+                            const upb_handlerattr *attr);
+bool upb_handlers_setuint64(upb_handlers *h, const upb_fielddef *f,
+                            upb_uint64_handlerfunc *func,
+                            const upb_handlerattr *attr);
+bool upb_handlers_setfloat(upb_handlers *h, const upb_fielddef *f,
+                           upb_float_handlerfunc *func,
+                           const upb_handlerattr *attr);
+bool upb_handlers_setdouble(upb_handlers *h, const upb_fielddef *f,
+                            upb_double_handlerfunc *func,
+                            const upb_handlerattr *attr);
+bool upb_handlers_setbool(upb_handlers *h, const upb_fielddef *f,
+                          upb_bool_handlerfunc *func,
+                          const upb_handlerattr *attr);
+bool upb_handlers_setstartstr(upb_handlers *h, const upb_fielddef *f,
+                              upb_startstr_handlerfunc *func,
+                              const upb_handlerattr *attr);
+bool upb_handlers_setstring(upb_handlers *h, const upb_fielddef *f,
+                            upb_string_handlerfunc *func,
+                            const upb_handlerattr *attr);
+bool upb_handlers_setendstr(upb_handlers *h, const upb_fielddef *f,
+                            upb_endfield_handlerfunc *func,
+                            const upb_handlerattr *attr);
+bool upb_handlers_setstartseq(upb_handlers *h, const upb_fielddef *f,
+                              upb_startfield_handlerfunc *func,
+                              const upb_handlerattr *attr);
+bool upb_handlers_setstartsubmsg(upb_handlers *h, const upb_fielddef *f,
+                                 upb_startfield_handlerfunc *func,
+                                 const upb_handlerattr *attr);
+bool upb_handlers_setendsubmsg(upb_handlers *h, const upb_fielddef *f,
+                               upb_endfield_handlerfunc *func,
+                               const upb_handlerattr *attr);
+bool upb_handlers_setendseq(upb_handlers *h, const upb_fielddef *f,
+                            upb_endfield_handlerfunc *func,
+                            const upb_handlerattr *attr);
+
+/* Read-only accessors. */
+const upb_handlers *upb_handlers_getsubhandlers(const upb_handlers *h,
+                                                const upb_fielddef *f);
+const upb_handlers *upb_handlers_getsubhandlers_sel(const upb_handlers *h,
+                                                    upb_selector_t sel);
+upb_func *upb_handlers_gethandler(const upb_handlers *h, upb_selector_t s,
+                                  const void **handler_data);
+bool upb_handlers_getattr(const upb_handlers *h, upb_selector_t s,
+                          upb_handlerattr *attr);
+
+/* "Static" methods */
+upb_handlertype_t upb_handlers_getprimitivehandlertype(const upb_fielddef *f);
+bool upb_handlers_getselector(const upb_fielddef *f, upb_handlertype_t type,
+                              upb_selector_t *s);
+UPB_INLINE upb_selector_t upb_handlers_getendselector(upb_selector_t start) {
+  return start + 1;
+}
+
+/* Internal-only. */
+uint32_t upb_handlers_selectorbaseoffset(const upb_fielddef *f);
+uint32_t upb_handlers_selectorcount(const upb_fielddef *f);
+
+#ifdef __cplusplus
+}  /* extern "C" */
+
+namespace upb {
+typedef upb_handlers Handlers;
+}
+
+/* Convenience macros for creating a Handler object that is wrapped with a
+ * type-safe wrapper function that converts the "void*" parameters/returns
+ * of the underlying C API into nice C++ function.
+ *
+ * Sample usage:
+ *   void OnValue1(MyClosure* c, const MyHandlerData* d, int32_t val) {
+ *     // do stuff ...
+ *   }
+ *
+ *   // Handler that doesn't need any data bound to it.
+ *   void OnValue2(MyClosure* c, int32_t val) {
+ *     // do stuff ...
+ *   }
+ *
+ *   // Handler that returns bool so it can return failure if necessary.
+ *   bool OnValue3(MyClosure* c, int32_t val) {
+ *     // do stuff ...
+ *     return ok;
+ *   }
+ *
+ *   // Member function handler.
+ *   class MyClosure {
+ *    public:
+ *     void OnValue(int32_t val) {
+ *       // do stuff ...
+ *     }
+ *   };
+ *
+ *   // Takes ownership of the MyHandlerData.
+ *   handlers->SetInt32Handler(f1, UpbBind(OnValue1, new MyHandlerData(...)));
+ *   handlers->SetInt32Handler(f2, UpbMakeHandler(OnValue2));
+ *   handlers->SetInt32Handler(f1, UpbMakeHandler(OnValue3));
+ *   handlers->SetInt32Handler(f2, UpbMakeHandler(&MyClosure::OnValue));
+ */
+
+/* In C++11, the "template" disambiguator can appear even outside templates,
+ * so all calls can safely use this pair of macros. */
+
+#define UpbMakeHandler(f) upb::MatchFunc(f).template GetFunc<f>()
+
+/* We have to be careful to only evaluate "d" once. */
+#define UpbBind(f, d) upb::MatchFunc(f).template GetFunc<f>((d))
+
+/* Handler: a struct that contains the (handler, data, deleter) tuple that is
+ * used to register all handlers.  Users can Make() these directly but it's
+ * more convenient to use the UpbMakeHandler/UpbBind macros above. */
+template <class T> class upb::Handler {
+ public:
+  /* The underlying, handler function signature that upb uses internally. */
+  typedef T FuncPtr;
+
+  /* Intentionally implicit. */
+  template <class F> Handler(F func);
+  ~Handler() { UPB_ASSERT(registered_); }
+
+  void AddCleanup(upb_handlers* h) const;
+  FuncPtr handler() const { return handler_; }
+  const upb_handlerattr& attr() const { return attr_; }
+
+ private:
+  Handler(const Handler&) = delete;
+  Handler& operator=(const Handler&) = delete;
+
+  FuncPtr handler_;
+  mutable upb_handlerattr attr_;
+  mutable bool registered_;
+  void *cleanup_data_;
+  upb_handlerfree *cleanup_func_;
+};
 
 /* A upb::Handlers object represents the set of handlers associated with a
  * message in the graph of messages.  You can think of it as a big virtual
@@ -4206,18 +4278,24 @@
  *
  * The easiest way to create the *Handler objects needed by the Set* methods is
  * with the UpbBind() and UpbMakeHandler() macros; see below. */
-class upb::Handlers {
+class upb::HandlersPtr {
  public:
+  HandlersPtr(upb_handlers* ptr) : ptr_(ptr) {}
+
+  upb_handlers* ptr() const { return ptr_; }
+
   typedef upb_selector_t Selector;
   typedef upb_handlertype_t Type;
 
   typedef Handler<void *(*)(void *, const void *)> StartFieldHandler;
   typedef Handler<bool (*)(void *, const void *)> EndFieldHandler;
   typedef Handler<bool (*)(void *, const void *)> StartMessageHandler;
-  typedef Handler<bool (*)(void *, const void *, Status*)> EndMessageHandler;
+  typedef Handler<bool (*)(void *, const void *, upb_status *)>
+      EndMessageHandler;
   typedef Handler<void *(*)(void *, const void *, size_t)> StartStringHandler;
   typedef Handler<size_t (*)(void *, const void *, const char *, size_t,
-                             const BufferHandle *)> StringHandler;
+                             const upb_bufhandle *)>
+      StringHandler;
 
   template <class T> struct ValueHandler {
     typedef Handler<bool(*)(void *, const void *, T)> H;
@@ -4237,47 +4315,17 @@
 
   typedef void HandlersCallback(const void *closure, upb_handlers *h);
 
-  /* Returns a new handlers object for the given frozen msgdef.
-   * Returns NULL if memory allocation failed. */
-  static reffed_ptr<Handlers> New(const MessageDef *m);
-
-  /* Convenience function for registering a graph of handlers that mirrors the
-   * graph of msgdefs for some message.  For "m" and all its children a new set
-   * of handlers will be created and the given callback will be invoked,
-   * allowing the client to register handlers for this message.  Note that any
-   * subhandlers set by the callback will be overwritten. */
-  static reffed_ptr<const Handlers> NewFrozen(const MessageDef *m,
-                                              HandlersCallback *callback,
-                                              const void *closure);
-
-  /* Functionality from upb::RefCounted. */
-  UPB_REFCOUNTED_CPPMETHODS
-
-  /* All handler registration functions return bool to indicate success or
-   * failure; details about failures are stored in this status object.  If a
-   * failure does occur, it must be cleared before the Handlers are frozen,
-   * otherwise the freeze() operation will fail.  The functions may *only* be
-   * used while the Handlers are mutable. */
-  const Status* status();
-  void ClearError();
-
-  /* Call to freeze these Handlers.  Requires that any SubHandlers are already
-   * frozen.  For cycles, you must use the static version below and freeze the
-   * whole graph at once. */
-  bool Freeze(Status* s);
-
-  /* Freezes the given set of handlers.  You may not freeze a handler without
-   * also freezing any handlers they point to. */
-  static bool Freeze(Handlers*const* handlers, int n, Status* s);
-  static bool Freeze(const std::vector<Handlers*>& handlers, Status* s);
-
   /* Returns the msgdef associated with this handlers object. */
-  const MessageDef* message_def() const;
+  MessageDefPtr message_def() const {
+    return MessageDefPtr(upb_handlers_msgdef(ptr()));
+  }
 
   /* Adds the given pointer and function to the list of cleanup functions that
    * will be run when these handlers are freed.  If this pointer has previously
    * been registered, the function returns false and does nothing. */
-  bool AddCleanup(void *ptr, upb_handlerfree *cleanup);
+  bool AddCleanup(void *ptr, upb_handlerfree *cleanup) {
+    return upb_handlers_addcleanup(ptr_, ptr, cleanup);
+  }
 
   /* Sets the startmsg handler for the message, which is defined as follows:
    *
@@ -4287,7 +4335,10 @@
    *     return true;
    *   }
    */
-  bool SetStartMessageHandler(const StartMessageHandler& handler);
+  bool SetStartMessageHandler(const StartMessageHandler &h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setstartmsg(ptr(), h.handler(), &h.attr());
+  }
 
   /* Sets the endmsg handler for the message, which is defined as follows:
    *
@@ -4297,7 +4348,10 @@
    *     // can also be modified in-place to update the final status.
    *   }
    */
-  bool SetEndMessageHandler(const EndMessageHandler& handler);
+  bool SetEndMessageHandler(const EndMessageHandler& h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setendmsg(ptr(), h.handler(), &h.attr());
+  }
 
   /* Sets the value handler for the given field, which is defined as follows
    * (this is for an int32 field; other field types will pass their native
@@ -4319,13 +4373,40 @@
    * Returns false if the handler failed to register; in this case the cleanup
    * handler (if any) will be called immediately.
    */
-  bool SetInt32Handler (const FieldDef* f,  const Int32Handler& h);
-  bool SetInt64Handler (const FieldDef* f,  const Int64Handler& h);
-  bool SetUInt32Handler(const FieldDef* f, const UInt32Handler& h);
-  bool SetUInt64Handler(const FieldDef* f, const UInt64Handler& h);
-  bool SetFloatHandler (const FieldDef* f,  const FloatHandler& h);
-  bool SetDoubleHandler(const FieldDef* f, const DoubleHandler& h);
-  bool SetBoolHandler  (const FieldDef* f,   const BoolHandler& h);
+  bool SetInt32Handler(FieldDefPtr f, const Int32Handler &h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setint32(ptr(), f.ptr(), h.handler(), &h.attr());
+  }
+
+  bool SetInt64Handler (FieldDefPtr f,  const Int64Handler& h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setint64(ptr(), f.ptr(), h.handler(), &h.attr());
+  }
+
+  bool SetUInt32Handler(FieldDefPtr f, const UInt32Handler& h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setuint32(ptr(), f.ptr(), h.handler(), &h.attr());
+  }
+
+  bool SetUInt64Handler(FieldDefPtr f, const UInt64Handler& h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setuint64(ptr(), f.ptr(), h.handler(), &h.attr());
+  }
+
+  bool SetFloatHandler (FieldDefPtr f,  const FloatHandler& h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setfloat(ptr(), f.ptr(), h.handler(), &h.attr());
+  }
+
+  bool SetDoubleHandler(FieldDefPtr f, const DoubleHandler& h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setdouble(ptr(), f.ptr(), h.handler(), &h.attr());
+  }
+
+  bool SetBoolHandler(FieldDefPtr f, const BoolHandler &h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setbool(ptr(), f.ptr(), h.handler(), &h.attr());
+  }
 
   /* Like the previous, but templated on the type on the value (ie. int32).
    * This is mostly useful to call from other templates.  To call this you must
@@ -4333,8 +4414,8 @@
    *   h->SetValueHandler<T>(f, UpbBind(MyHandler<T>, MyData)); */
   template <class T>
   bool SetValueHandler(
-      const FieldDef *f,
-      const typename ValueHandler<typename CanonicalType<T>::Type>::H& handler);
+      FieldDefPtr f,
+      const typename ValueHandler<typename CanonicalType<T>::Type>::H &handler);
 
   /* Sets handlers for a string field, which are defined as follows:
    *
@@ -4372,9 +4453,20 @@
    *     return true;
    *   }
    */
-  bool SetStartStringHandler(const FieldDef* f, const StartStringHandler& h);
-  bool SetStringHandler(const FieldDef* f, const StringHandler& h);
-  bool SetEndStringHandler(const FieldDef* f, const EndFieldHandler& h);
+  bool SetStartStringHandler(FieldDefPtr f, const StartStringHandler &h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setstartstr(ptr(), f.ptr(), h.handler(), &h.attr());
+  }
+
+  bool SetStringHandler(FieldDefPtr f, const StringHandler& h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setstring(ptr(), f.ptr(), h.handler(), &h.attr());
+  }
+
+  bool SetEndStringHandler(FieldDefPtr f, const EndFieldHandler& h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setendstr(ptr(), f.ptr(), h.handler(), &h.attr());
+  }
 
   /* Sets the startseq handler, which is defined as follows:
    *
@@ -4390,7 +4482,10 @@
    * Returns "false" if "f" does not belong to this message or is not a
    * repeated field.
    */
-  bool SetStartSequenceHandler(const FieldDef* f, const StartFieldHandler& h);
+  bool SetStartSequenceHandler(FieldDefPtr f, const StartFieldHandler &h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setstartseq(ptr(), f.ptr(), h.handler(), &h.attr());
+  }
 
   /* Sets the startsubmsg handler for the given field, which is defined as
    * follows:
@@ -4407,7 +4502,10 @@
    * Returns "false" if "f" does not belong to this message or is not a
    * submessage/group field.
    */
-  bool SetStartSubMessageHandler(const FieldDef* f, const StartFieldHandler& h);
+  bool SetStartSubMessageHandler(FieldDefPtr f, const StartFieldHandler& h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setstartsubmsg(ptr(), f.ptr(), h.handler(), &h.attr());
+  }
 
   /* Sets the endsubmsg handler for the given field, which is defined as
    * follows:
@@ -4420,7 +4518,10 @@
    * Returns "false" if "f" does not belong to this message or is not a
    * submessage/group field.
    */
-  bool SetEndSubMessageHandler(const FieldDef *f, const EndFieldHandler &h);
+  bool SetEndSubMessageHandler(FieldDefPtr f, const EndFieldHandler &h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setendsubmsg(ptr(), f.ptr(), h.handler(), &h.attr());
+  }
 
   /* Starts the endsubseq handler for the given field, which is defined as
    * follows:
@@ -4433,315 +4534,102 @@
    * Returns "false" if "f" does not belong to this message or is not a
    * repeated field.
    */
-  bool SetEndSequenceHandler(const FieldDef* f, const EndFieldHandler& h);
-
-  /* Sets or gets the object that specifies handlers for the given field, which
-   * must be a submessage or group.  Returns NULL if no handlers are set. */
-  bool SetSubHandlers(const FieldDef* f, const Handlers* sub);
-  const Handlers* GetSubHandlers(const FieldDef* f) const;
-
-  /* Equivalent to GetSubHandlers, but takes the STARTSUBMSG selector for the
-   * field. */
-  const Handlers* GetSubHandlers(Selector startsubmsg) const;
-
-  /* A selector refers to a specific field handler in the Handlers object
-   * (for example: the STARTSUBMSG handler for field "field15").
-   * On success, returns true and stores the selector in "s".
-   * If the FieldDef or Type are invalid, returns false.
-   * The returned selector is ONLY valid for Handlers whose MessageDef
-   * contains this FieldDef. */
-  static bool GetSelector(const FieldDef* f, Type type, Selector* s);
-
-  /* Given a START selector of any kind, returns the corresponding END selector. */
-  static Selector GetEndSelector(Selector start_selector);
-
-  /* Returns the function pointer for this handler.  It is the client's
-   * responsibility to cast to the correct function type before calling it. */
-  GenericFunction* GetHandler(Selector selector);
-
-  /* Sets the given attributes to the attributes for this selector. */
-  bool GetAttributes(Selector selector, HandlerAttributes* attr);
-
-  /* Returns the handler data that was registered with this handler. */
-  const void* GetHandlerData(Selector selector);
-
-  /* Could add any of the following functions as-needed, with some minor
-   * implementation changes:
-   *
-   * const FieldDef* GetFieldDef(Selector selector);
-   * static bool IsSequence(Selector selector); */
-
- private:
-  UPB_DISALLOW_POD_OPS(Handlers, upb::Handlers)
-
-  friend UPB_INLINE GenericFunction *::upb_handlers_gethandler(
-      const upb_handlers *h, upb_selector_t s);
-  friend UPB_INLINE const void *::upb_handlers_gethandlerdata(
-      const upb_handlers *h, upb_selector_t s);
-#else
-struct upb_handlers {
-#endif
-  upb_refcounted base;
-
-  const upb_msgdef *msg;
-  const upb_handlers **sub;
-  const void *top_closure_type;
-  upb_inttable cleanup_;
-  upb_status status_;  /* Used only when mutable. */
-  upb_handlers_tabent table[1];  /* Dynamically-sized field handler array. */
-};
-
-#ifdef __cplusplus
-
-namespace upb {
-
-/* Convenience macros for creating a Handler object that is wrapped with a
- * type-safe wrapper function that converts the "void*" parameters/returns
- * of the underlying C API into nice C++ function.
- *
- * Sample usage:
- *   void OnValue1(MyClosure* c, const MyHandlerData* d, int32_t val) {
- *     // do stuff ...
- *   }
- *
- *   // Handler that doesn't need any data bound to it.
- *   void OnValue2(MyClosure* c, int32_t val) {
- *     // do stuff ...
- *   }
- *
- *   // Handler that returns bool so it can return failure if necessary.
- *   bool OnValue3(MyClosure* c, int32_t val) {
- *     // do stuff ...
- *     return ok;
- *   }
- *
- *   // Member function handler.
- *   class MyClosure {
- *    public:
- *     void OnValue(int32_t val) {
- *       // do stuff ...
- *     }
- *   };
- *
- *   // Takes ownership of the MyHandlerData.
- *   handlers->SetInt32Handler(f1, UpbBind(OnValue1, new MyHandlerData(...)));
- *   handlers->SetInt32Handler(f2, UpbMakeHandler(OnValue2));
- *   handlers->SetInt32Handler(f1, UpbMakeHandler(OnValue3));
- *   handlers->SetInt32Handler(f2, UpbMakeHandler(&MyClosure::OnValue));
- */
-
-#ifdef UPB_CXX11
-
-/* In C++11, the "template" disambiguator can appear even outside templates,
- * so all calls can safely use this pair of macros. */
-
-#define UpbMakeHandler(f) upb::MatchFunc(f).template GetFunc<f>()
-
-/* We have to be careful to only evaluate "d" once. */
-#define UpbBind(f, d) upb::MatchFunc(f).template GetFunc<f>((d))
-
-#else
-
-/* Prior to C++11, the "template" disambiguator may only appear inside a
- * template, so the regular macro must not use "template" */
-
-#define UpbMakeHandler(f) upb::MatchFunc(f).GetFunc<f>()
-
-#define UpbBind(f, d) upb::MatchFunc(f).GetFunc<f>((d))
-
-#endif  /* UPB_CXX11 */
-
-/* This macro must be used in C++98 for calls from inside a template.  But we
- * define this variant in all cases; code that wants to be compatible with both
- * C++98 and C++11 should always use this macro when calling from a template. */
-#define UpbMakeHandlerT(f) upb::MatchFunc(f).template GetFunc<f>()
-
-/* We have to be careful to only evaluate "d" once. */
-#define UpbBindT(f, d) upb::MatchFunc(f).template GetFunc<f>((d))
-
-/* Handler: a struct that contains the (handler, data, deleter) tuple that is
- * used to register all handlers.  Users can Make() these directly but it's
- * more convenient to use the UpbMakeHandler/UpbBind macros above. */
-template <class T> class Handler {
- public:
-  /* The underlying, handler function signature that upb uses internally. */
-  typedef T FuncPtr;
-
-  /* Intentionally implicit. */
-  template <class F> Handler(F func);
-  ~Handler();
-
- private:
-  void AddCleanup(Handlers* h) const {
-    if (cleanup_func_) {
-      bool ok = h->AddCleanup(cleanup_data_, cleanup_func_);
-      UPB_ASSERT(ok);
-    }
+  bool SetEndSequenceHandler(FieldDefPtr f, const EndFieldHandler &h) {
+    h.AddCleanup(ptr());
+    return upb_handlers_setendseq(ptr(), f.ptr(), h.handler(), &h.attr());
   }
 
-  UPB_DISALLOW_COPY_AND_ASSIGN(Handler)
-  friend class Handlers;
-  FuncPtr handler_;
-  mutable HandlerAttributes attr_;
-  mutable bool registered_;
-  void *cleanup_data_;
-  upb_handlerfree *cleanup_func_;
+ private:
+  upb_handlers* ptr_;
 };
 
-}  /* namespace upb */
-
 #endif  /* __cplusplus */
 
-UPB_BEGIN_EXTERN_C
+/* upb_handlercache ***********************************************************/
 
-/* Native C API. */
+/* A upb_handlercache lazily builds and caches upb_handlers.  You pass it a
+ * function (with optional closure) that can build handlers for a given
+ * message on-demand, and the cache maintains a map of msgdef->handlers. */
 
-/* Handler function typedefs. */
-typedef bool upb_unknown_handlerfunc(void *c, const void *hd, const char *buf,
-                                     size_t n);
-typedef bool upb_startmsg_handlerfunc(void *c, const void*);
-typedef bool upb_endmsg_handlerfunc(void *c, const void *, upb_status *status);
-typedef void* upb_startfield_handlerfunc(void *c, const void *hd);
-typedef bool upb_endfield_handlerfunc(void *c, const void *hd);
-typedef bool upb_int32_handlerfunc(void *c, const void *hd, int32_t val);
-typedef bool upb_int64_handlerfunc(void *c, const void *hd, int64_t val);
-typedef bool upb_uint32_handlerfunc(void *c, const void *hd, uint32_t val);
-typedef bool upb_uint64_handlerfunc(void *c, const void *hd, uint64_t val);
-typedef bool upb_float_handlerfunc(void *c, const void *hd, float val);
-typedef bool upb_double_handlerfunc(void *c, const void *hd, double val);
-typedef bool upb_bool_handlerfunc(void *c, const void *hd, bool val);
-typedef void *upb_startstr_handlerfunc(void *c, const void *hd,
-                                       size_t size_hint);
-typedef size_t upb_string_handlerfunc(void *c, const void *hd, const char *buf,
-                                      size_t n, const upb_bufhandle* handle);
+#ifdef __cplusplus
+extern "C" {
+#endif
 
-/* upb_bufhandle */
-size_t upb_bufhandle_objofs(const upb_bufhandle *h);
+struct upb_handlercache;
+typedef struct upb_handlercache upb_handlercache;
 
-/* upb_handlerattr */
-void upb_handlerattr_init(upb_handlerattr *attr);
-void upb_handlerattr_uninit(upb_handlerattr *attr);
-
-bool upb_handlerattr_sethandlerdata(upb_handlerattr *attr, const void *hd);
-bool upb_handlerattr_setclosuretype(upb_handlerattr *attr, const void *type);
-const void *upb_handlerattr_closuretype(const upb_handlerattr *attr);
-bool upb_handlerattr_setreturnclosuretype(upb_handlerattr *attr,
-                                          const void *type);
-const void *upb_handlerattr_returnclosuretype(const upb_handlerattr *attr);
-bool upb_handlerattr_setalwaysok(upb_handlerattr *attr, bool alwaysok);
-bool upb_handlerattr_alwaysok(const upb_handlerattr *attr);
-
-UPB_INLINE const void *upb_handlerattr_handlerdata(
-    const upb_handlerattr *attr) {
-  return attr->handler_data_;
-}
-
-/* upb_handlers */
 typedef void upb_handlers_callback(const void *closure, upb_handlers *h);
-upb_handlers *upb_handlers_new(const upb_msgdef *m,
-                               const void *owner);
-const upb_handlers *upb_handlers_newfrozen(const upb_msgdef *m,
-                                           const void *owner,
-                                           upb_handlers_callback *callback,
-                                           const void *closure);
 
-/* Include refcounted methods like upb_handlers_ref(). */
-UPB_REFCOUNTED_CMETHODS(upb_handlers, upb_handlers_upcast)
+upb_handlercache *upb_handlercache_new(upb_handlers_callback *callback,
+                                       const void *closure);
+void upb_handlercache_free(upb_handlercache *cache);
+const upb_handlers *upb_handlercache_get(upb_handlercache *cache,
+                                         const upb_msgdef *md);
+bool upb_handlercache_addcleanup(upb_handlercache *h, void *p,
+                                 upb_handlerfree *hfree);
 
-const upb_status *upb_handlers_status(upb_handlers *h);
-void upb_handlers_clearerr(upb_handlers *h);
-const upb_msgdef *upb_handlers_msgdef(const upb_handlers *h);
-bool upb_handlers_addcleanup(upb_handlers *h, void *p, upb_handlerfree *hfree);
-bool upb_handlers_setunknown(upb_handlers *h, upb_unknown_handlerfunc *func,
-                             upb_handlerattr *attr);
+#ifdef __cplusplus
+}  /* extern "C" */
 
-bool upb_handlers_setstartmsg(upb_handlers *h, upb_startmsg_handlerfunc *func,
-                              upb_handlerattr *attr);
-bool upb_handlers_setendmsg(upb_handlers *h, upb_endmsg_handlerfunc *func,
-                            upb_handlerattr *attr);
-bool upb_handlers_setint32(upb_handlers *h, const upb_fielddef *f,
-                           upb_int32_handlerfunc *func, upb_handlerattr *attr);
-bool upb_handlers_setint64(upb_handlers *h, const upb_fielddef *f,
-                           upb_int64_handlerfunc *func, upb_handlerattr *attr);
-bool upb_handlers_setuint32(upb_handlers *h, const upb_fielddef *f,
-                            upb_uint32_handlerfunc *func,
-                            upb_handlerattr *attr);
-bool upb_handlers_setuint64(upb_handlers *h, const upb_fielddef *f,
-                            upb_uint64_handlerfunc *func,
-                            upb_handlerattr *attr);
-bool upb_handlers_setfloat(upb_handlers *h, const upb_fielddef *f,
-                           upb_float_handlerfunc *func, upb_handlerattr *attr);
-bool upb_handlers_setdouble(upb_handlers *h, const upb_fielddef *f,
-                            upb_double_handlerfunc *func,
-                            upb_handlerattr *attr);
-bool upb_handlers_setbool(upb_handlers *h, const upb_fielddef *f,
-                          upb_bool_handlerfunc *func,
-                          upb_handlerattr *attr);
-bool upb_handlers_setstartstr(upb_handlers *h, const upb_fielddef *f,
-                              upb_startstr_handlerfunc *func,
-                              upb_handlerattr *attr);
-bool upb_handlers_setstring(upb_handlers *h, const upb_fielddef *f,
-                            upb_string_handlerfunc *func,
-                            upb_handlerattr *attr);
-bool upb_handlers_setendstr(upb_handlers *h, const upb_fielddef *f,
-                            upb_endfield_handlerfunc *func,
-                            upb_handlerattr *attr);
-bool upb_handlers_setstartseq(upb_handlers *h, const upb_fielddef *f,
-                              upb_startfield_handlerfunc *func,
-                              upb_handlerattr *attr);
-bool upb_handlers_setstartsubmsg(upb_handlers *h, const upb_fielddef *f,
-                                 upb_startfield_handlerfunc *func,
-                                 upb_handlerattr *attr);
-bool upb_handlers_setendsubmsg(upb_handlers *h, const upb_fielddef *f,
-                               upb_endfield_handlerfunc *func,
-                               upb_handlerattr *attr);
-bool upb_handlers_setendseq(upb_handlers *h, const upb_fielddef *f,
-                            upb_endfield_handlerfunc *func,
-                            upb_handlerattr *attr);
+class upb::HandlerCache {
+ public:
+  HandlerCache(upb_handlers_callback *callback, const void *closure)
+      : ptr_(upb_handlercache_new(callback, closure), upb_handlercache_free) {}
+  HandlerCache(HandlerCache&&) = default;
+  HandlerCache& operator=(HandlerCache&&) = default;
+  HandlerCache(upb_handlercache* c) : ptr_(c, upb_handlercache_free) {}
 
-bool upb_handlers_setsubhandlers(upb_handlers *h, const upb_fielddef *f,
-                                 const upb_handlers *sub);
-const upb_handlers *upb_handlers_getsubhandlers(const upb_handlers *h,
-                                                const upb_fielddef *f);
-const upb_handlers *upb_handlers_getsubhandlers_sel(const upb_handlers *h,
-                                                    upb_selector_t sel);
+  upb_handlercache* ptr() { return ptr_.get(); }
 
-UPB_INLINE upb_func *upb_handlers_gethandler(const upb_handlers *h,
-                                             upb_selector_t s) {
-  return (upb_func *)h->table[s].func;
-}
+  const upb_handlers *Get(MessageDefPtr md) {
+    return upb_handlercache_get(ptr_.get(), md.ptr());
+  }
 
-bool upb_handlers_getattr(const upb_handlers *h, upb_selector_t s,
-                          upb_handlerattr *attr);
+ private:
+  std::unique_ptr<upb_handlercache, decltype(&upb_handlercache_free)> ptr_;
+};
 
-UPB_INLINE const void *upb_handlers_gethandlerdata(const upb_handlers *h,
-                                                   upb_selector_t s) {
-  return upb_handlerattr_handlerdata(&h->table[s].attr);
+#endif  /* __cplusplus */
+
+/* upb_byteshandler ***********************************************************/
+
+typedef struct {
+  upb_func *func;
+
+  /* It is wasteful to include the entire attributes here:
+   *
+   * * Some of the information is redundant (like storing the closure type
+   *   separately for each handler that must match).
+   * * Some of the info is only needed prior to freeze() (like closure types).
+   * * alignment padding wastes a lot of space for alwaysok_.
+   *
+   * If/when the size and locality of handlers is an issue, we can optimize this
+   * not to store the entire attr like this.  We do not expose the table's
+   * layout to allow this optimization in the future. */
+  upb_handlerattr attr;
+} upb_handlers_tabent;
+
+#define UPB_TABENT_INIT {NULL, UPB_HANDLERATTR_INIT}
+
+typedef struct {
+  upb_handlers_tabent table[3];
+} upb_byteshandler;
+
+#define UPB_BYTESHANDLER_INIT                             \
+  {                                                       \
+    { UPB_TABENT_INIT, UPB_TABENT_INIT, UPB_TABENT_INIT } \
+  }
+
+UPB_INLINE void upb_byteshandler_init(upb_byteshandler *handler) {
+  upb_byteshandler init = UPB_BYTESHANDLER_INIT;
+  *handler = init;
 }
 
 #ifdef __cplusplus
-
-/* Handler types for single fields.
- * Right now we only have one for TYPE_BYTES but ones for other types
- * should follow.
- *
- * These follow the same handlers protocol for fields of a message. */
-class upb::BytesHandler {
- public:
-  BytesHandler();
-  ~BytesHandler();
-#else
-struct upb_byteshandler {
+extern "C" {
 #endif
-  upb_handlers_tabent table[3];
-};
 
-void upb_byteshandler_init(upb_byteshandler *h);
-
-/* Caller must ensure that "d" outlives the handlers.
- * TODO(haberman): should this have a "freeze" operation?  It's not necessary
- * for memory management, but could be useful to force immutability and provide
- * a convenient moment to verify that all registration succeeded. */
+/* Caller must ensure that "d" outlives the handlers. */
 bool upb_byteshandler_setstartstr(upb_byteshandler *h,
                                   upb_startstr_handlerfunc *func, void *d);
 bool upb_byteshandler_setstring(upb_byteshandler *h,
@@ -4749,22 +4637,20 @@
 bool upb_byteshandler_setendstr(upb_byteshandler *h,
                                 upb_endfield_handlerfunc *func, void *d);
 
-/* "Static" methods */
-bool upb_handlers_freeze(upb_handlers *const *handlers, int n, upb_status *s);
-upb_handlertype_t upb_handlers_getprimitivehandlertype(const upb_fielddef *f);
-bool upb_handlers_getselector(const upb_fielddef *f, upb_handlertype_t type,
-                              upb_selector_t *s);
-UPB_INLINE upb_selector_t upb_handlers_getendselector(upb_selector_t start) {
-  return start + 1;
+#ifdef __cplusplus
+}  /* extern "C" */
+
+namespace upb {
+typedef upb_byteshandler BytesHandler;
 }
-
-/* Internal-only. */
-uint32_t upb_handlers_selectorbaseoffset(const upb_fielddef *f);
-uint32_t upb_handlers_selectorcount(const upb_fielddef *f);
-
+#endif
 
 /** Message handlers ******************************************************************/
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* These are the handlers used internally by upb_msgfactory_getmergehandlers().
  * They write scalar data to a known offset from the message pointer.
  *
@@ -4790,7 +4676,9 @@
 
 
 
-UPB_END_EXTERN_C
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
 
 /*
 ** Inline definitions for handlers.h, which are particularly long and a bit
@@ -4801,39 +4689,7 @@
 #define UPB_HANDLERS_INL_H_
 
 #include <limits.h>
-
-/* C inline methods. */
-
-/* upb_bufhandle */
-UPB_INLINE void upb_bufhandle_init(upb_bufhandle *h) {
-  h->obj_ = NULL;
-  h->objtype_ = NULL;
-  h->buf_ = NULL;
-  h->objofs_ = 0;
-}
-UPB_INLINE void upb_bufhandle_uninit(upb_bufhandle *h) {
-  UPB_UNUSED(h);
-}
-UPB_INLINE void upb_bufhandle_setobj(upb_bufhandle *h, const void *obj,
-                                     const void *type) {
-  h->obj_ = obj;
-  h->objtype_ = type;
-}
-UPB_INLINE void upb_bufhandle_setbuf(upb_bufhandle *h, const char *buf,
-                                     size_t ofs) {
-  h->buf_ = buf;
-  h->objofs_ = ofs;
-}
-UPB_INLINE const void *upb_bufhandle_obj(const upb_bufhandle *h) {
-  return h->obj_;
-}
-UPB_INLINE const void *upb_bufhandle_objtype(const upb_bufhandle *h) {
-  return h->objtype_;
-}
-UPB_INLINE const char *upb_bufhandle_buf(const upb_bufhandle *h) {
-  return h->buf_;
-}
-
+#include <stddef.h>
 
 #ifdef __cplusplus
 
@@ -4989,8 +4845,8 @@
  * These functions are not bound to a handler data so have no data or cleanup
  * handler. */
 struct UnboundFunc {
-  CleanupFunc *GetCleanup() { return NULL; }
-  void *GetData() { return NULL; }
+  CleanupFunc *GetCleanup() { return nullptr; }
+  void *GetData() { return nullptr; }
 };
 
 template <class R, class P1, R F(P1), class I>
@@ -5036,7 +4892,7 @@
 
 /* BoundFunc2, BoundFunc3: Like Func2/Func3 except also contains a value that
  * shall be bound to the function's second parameter.
- *
+ * 
  * Note that the second parameter is a const pointer, but our stored bound value
  * is non-const so we can free it when the handlers are destroyed. */
 template <class T>
@@ -5398,9 +5254,9 @@
 
 /* For the string callback, which takes five params, returns the size param. */
 template <class P1, class P2,
-          void F(P1, P2, const char *, size_t, const BufferHandle *)>
+          void F(P1, P2, const char *, size_t, const upb_bufhandle *)>
 size_t ReturnStringLen(P1 p1, P2 p2, const char *p3, size_t p4,
-                       const BufferHandle *p5) {
+                       const upb_bufhandle *p5) {
   F(p1, p2, p3, p4, p5);
   return p4;
 }
@@ -5408,9 +5264,9 @@
 /* For the string callback, which takes five params, returns the size param or
  * zero. */
 template <class P1, class P2,
-          bool F(P1, P2, const char *, size_t, const BufferHandle *)>
+          bool F(P1, P2, const char *, size_t, const upb_bufhandle *)>
 size_t ReturnNOr0(P1 p1, P2 p2, const char *p3, size_t p4,
-                  const BufferHandle *p5) {
+                  const upb_bufhandle *p5) {
   return F(p1, p2, p3, p4, p5) ? p4 : 0;
 }
 
@@ -5469,22 +5325,22 @@
 /* If our function returns void but we want one returning size_t, wrap it in a
  * function that returns the size argument. */
 template <class P1, class P2,
-          void F(P1, P2, const char *, size_t, const BufferHandle *), class I>
+          void F(P1, P2, const char *, size_t, const upb_bufhandle *), class I>
 struct MaybeWrapReturn<
-    Func5<void, P1, P2, const char *, size_t, const BufferHandle *, F, I>,
+    Func5<void, P1, P2, const char *, size_t, const upb_bufhandle *, F, I>,
           size_t> {
-  typedef Func5<size_t, P1, P2, const char *, size_t, const BufferHandle *,
+  typedef Func5<size_t, P1, P2, const char *, size_t, const upb_bufhandle *,
                 ReturnStringLen<P1, P2, F>, I> Func;
 };
 
 /* If our function returns bool but we want one returning size_t, wrap it in a
  * function that returns either 0 or the buf size. */
 template <class P1, class P2,
-          bool F(P1, P2, const char *, size_t, const BufferHandle *), class I>
+          bool F(P1, P2, const char *, size_t, const upb_bufhandle *), class I>
 struct MaybeWrapReturn<
-    Func5<bool, P1, P2, const char *, size_t, const BufferHandle *, F, I>,
+    Func5<bool, P1, P2, const char *, size_t, const upb_bufhandle *, F, I>,
     size_t> {
-  typedef Func5<size_t, P1, P2, const char *, size_t, const BufferHandle *,
+  typedef Func5<size_t, P1, P2, const char *, size_t, const upb_bufhandle *,
                 ReturnNOr0<P1, P2, F>, I> Func;
 };
 
@@ -5525,7 +5381,7 @@
 
 template <class R, class P1, R F(P1, const char*, size_t)>
 R IgnoreHandlerDataIgnoreHandle(void *p1, const void *hd, const char *p2,
-                                size_t p3, const BufferHandle *handle) {
+                                size_t p3, const upb_bufhandle *handle) {
   UPB_UNUSED(hd);
   UPB_UNUSED(handle);
   return F(static_cast<P1>(p1), p2, p3);
@@ -5551,7 +5407,7 @@
 
 template <class R, class P1, class P2, R F(P1, P2, const char *, size_t)>
 R CastHandlerDataIgnoreHandle(void *c, const void *hd, const char *p3,
-                              size_t p4, const BufferHandle *handle) {
+                              size_t p4, const upb_bufhandle *handle) {
   UPB_UNUSED(handle);
   return F(static_cast<P1>(c), static_cast<P2>(hd), p3, p4);
 }
@@ -5571,11 +5427,11 @@
 };
 
 /* For StringBuffer only; this ignores both the handler data and the
- * BufferHandle. */
+ * upb_bufhandle. */
 template <class R, class P1, R F(P1, const char *, size_t), class I, class T>
 struct ConvertParams<Func3<R, P1, const char *, size_t, F, I>, T> {
   typedef Func5<R, void *, const void *, const char *, size_t,
-                const BufferHandle *, IgnoreHandlerDataIgnoreHandle<R, P1, F>,
+                const upb_bufhandle *, IgnoreHandlerDataIgnoreHandle<R, P1, F>,
                 I> Func;
 };
 
@@ -5601,13 +5457,14 @@
                 CastHandlerData3<R, P1, P2, P3_2, P3, F>, I> Func;
 };
 
-/* For StringBuffer only; this ignores the BufferHandle. */
+/* For StringBuffer only; this ignores the upb_bufhandle. */
 template <class R, class P1, class P2, R F(P1, P2, const char *, size_t),
           class I, class T>
 struct ConvertParams<BoundFunc4<R, P1, P2, const char *, size_t, F, I>, T> {
   typedef Func5<R, void *, const void *, const char *, size_t,
-                const BufferHandle *, CastHandlerDataIgnoreHandle<R, P1, P2, F>,
-                I> Func;
+                const upb_bufhandle *,
+                CastHandlerDataIgnoreHandle<R, P1, P2, F>, I>
+      Func;
 };
 
 template <class R, class P1, class P2, class P3, class P4, class P5,
@@ -5619,19 +5476,18 @@
 
 /* utype/ltype are upper/lower-case, ctype is canonical C type, vtype is
  * variant C type. */
-#define TYPE_METHODS(utype, ltype, ctype, vtype)                               \
-  template <> struct CanonicalType<vtype> {                                    \
-    typedef ctype Type;                                                        \
-  };                                                                           \
-  template <>                                                                  \
-  inline bool Handlers::SetValueHandler<vtype>(                                \
-      const FieldDef *f,                                                       \
-      const Handlers::utype ## Handler& handler) {                             \
-    UPB_ASSERT(!handler.registered_);                                              \
-    handler.AddCleanup(this);                                                  \
-    handler.registered_ = true;                                                \
-    return upb_handlers_set##ltype(this, f, handler.handler_, &handler.attr_); \
-  }                                                                            \
+#define TYPE_METHODS(utype, ltype, ctype, vtype)                      \
+  template <>                                                         \
+  struct CanonicalType<vtype> {                                       \
+    typedef ctype Type;                                               \
+  };                                                                  \
+  template <>                                                         \
+  inline bool HandlersPtr::SetValueHandler<vtype>(                    \
+      FieldDefPtr f, const HandlersPtr::utype##Handler &handler) {    \
+    handler.AddCleanup(ptr());                                        \
+    return upb_handlers_set##ltype(ptr(), f.ptr(), handler.handler(), \
+                                   &handler.attr());                  \
+  }
 
 TYPE_METHODS(Double, double, double,   double)
 TYPE_METHODS(Float,  float,  float,    float)
@@ -5656,24 +5512,6 @@
   typedef Status* Type;
 };
 
-/* Type methods that are only one-per-canonical-type and not
- * one-per-cvariant. */
-
-#define TYPE_METHODS(utype, ctype) \
-    inline bool Handlers::Set##utype##Handler(const FieldDef *f, \
-                                              const utype##Handler &h) { \
-      return SetValueHandler<ctype>(f, h); \
-    } \
-
-TYPE_METHODS(Double, double)
-TYPE_METHODS(Float,  float)
-TYPE_METHODS(UInt64, uint64_t)
-TYPE_METHODS(UInt32, uint32_t)
-TYPE_METHODS(Int64,  int64_t)
-TYPE_METHODS(Int32,  int32_t)
-TYPE_METHODS(Bool,   bool)
-#undef TYPE_METHODS
-
 template <class F> struct ReturnOf;
 
 template <class R, class P1, class P2>
@@ -5696,10 +5534,6 @@
   typedef R Return;
 };
 
-template<class T> const void *UniquePtrForType() {
-  static const char ch = 0;
-  return &ch;
-}
 
 template <class T>
 template <class F>
@@ -5707,7 +5541,7 @@
     : registered_(false),
       cleanup_data_(func.GetData()),
       cleanup_func_(func.GetCleanup()) {
-  upb_handlerattr_sethandlerdata(&attr_, func.GetData());
+  attr_.handler_data = func.GetData();
   typedef typename ReturnOf<T>::Return Return;
   typedef typename ConvertParams<F, T>::Func ConvertedParamsFunc;
   typedef typename MaybeWrapReturn<ConvertedParamsFunc, Return>::Func
@@ -5720,10 +5554,10 @@
   /* If the original function returns void, then we know that we wrapped it to
    * always return ok. */
   bool always_ok = is_same<typename F::FuncInfo::Return, void>::value;
-  attr_.SetAlwaysOk(always_ok);
+  attr_.alwaysok = always_ok;
 
   /* Closure parameter and return type. */
-  attr_.SetClosureType(UniquePtrForType<typename F::FuncInfo::Closure>());
+  attr_.closure_type = UniquePtrForType<typename F::FuncInfo::Closure>();
 
   /* We use the closure type (from the first parameter) if the return type is
    * void or bool, since these are the two cases we wrap to return the closure's
@@ -5734,188 +5568,19 @@
   typedef typename FirstUnlessVoidOrBool<typename F::FuncInfo::Return,
                                          typename F::FuncInfo::Closure>::value
       EffectiveReturn;
-  attr_.SetReturnClosureType(UniquePtrForType<EffectiveReturn>());
+  attr_.return_closure_type = UniquePtrForType<EffectiveReturn>();
 }
 
 template <class T>
-inline Handler<T>::~Handler() {
-  UPB_ASSERT(registered_);
+inline void Handler<T>::AddCleanup(upb_handlers* h) const {
+  UPB_ASSERT(!registered_);
+  registered_ = true;
+  if (cleanup_func_) {
+    bool ok = upb_handlers_addcleanup(h, cleanup_data_, cleanup_func_);
+    UPB_ASSERT(ok);
+  }
 }
 
-inline HandlerAttributes::HandlerAttributes() { upb_handlerattr_init(this); }
-inline HandlerAttributes::~HandlerAttributes() { upb_handlerattr_uninit(this); }
-inline bool HandlerAttributes::SetHandlerData(const void *hd) {
-  return upb_handlerattr_sethandlerdata(this, hd);
-}
-inline const void* HandlerAttributes::handler_data() const {
-  return upb_handlerattr_handlerdata(this);
-}
-inline bool HandlerAttributes::SetClosureType(const void *type) {
-  return upb_handlerattr_setclosuretype(this, type);
-}
-inline const void* HandlerAttributes::closure_type() const {
-  return upb_handlerattr_closuretype(this);
-}
-inline bool HandlerAttributes::SetReturnClosureType(const void *type) {
-  return upb_handlerattr_setreturnclosuretype(this, type);
-}
-inline const void* HandlerAttributes::return_closure_type() const {
-  return upb_handlerattr_returnclosuretype(this);
-}
-inline bool HandlerAttributes::SetAlwaysOk(bool always_ok) {
-  return upb_handlerattr_setalwaysok(this, always_ok);
-}
-inline bool HandlerAttributes::always_ok() const {
-  return upb_handlerattr_alwaysok(this);
-}
-
-inline BufferHandle::BufferHandle() { upb_bufhandle_init(this); }
-inline BufferHandle::~BufferHandle() { upb_bufhandle_uninit(this); }
-inline const char* BufferHandle::buffer() const {
-  return upb_bufhandle_buf(this);
-}
-inline size_t BufferHandle::object_offset() const {
-  return upb_bufhandle_objofs(this);
-}
-inline void BufferHandle::SetBuffer(const char* buf, size_t ofs) {
-  upb_bufhandle_setbuf(this, buf, ofs);
-}
-template <class T>
-void BufferHandle::SetAttachedObject(const T* obj) {
-  upb_bufhandle_setobj(this, obj, UniquePtrForType<T>());
-}
-template <class T>
-const T* BufferHandle::GetAttachedObject() const {
-  return upb_bufhandle_objtype(this) == UniquePtrForType<T>()
-      ? static_cast<const T *>(upb_bufhandle_obj(this))
-                               : NULL;
-}
-
-inline reffed_ptr<Handlers> Handlers::New(const MessageDef *m) {
-  upb_handlers *h = upb_handlers_new(m, &h);
-  return reffed_ptr<Handlers>(h, &h);
-}
-inline reffed_ptr<const Handlers> Handlers::NewFrozen(
-    const MessageDef *m, upb_handlers_callback *callback,
-    const void *closure) {
-  const upb_handlers *h = upb_handlers_newfrozen(m, &h, callback, closure);
-  return reffed_ptr<const Handlers>(h, &h);
-}
-inline const Status* Handlers::status() {
-  return upb_handlers_status(this);
-}
-inline void Handlers::ClearError() {
-  return upb_handlers_clearerr(this);
-}
-inline bool Handlers::Freeze(Status *s) {
-  upb::Handlers* h = this;
-  return upb_handlers_freeze(&h, 1, s);
-}
-inline bool Handlers::Freeze(Handlers *const *handlers, int n, Status *s) {
-  return upb_handlers_freeze(handlers, n, s);
-}
-inline bool Handlers::Freeze(const std::vector<Handlers*>& h, Status* status) {
-  return upb_handlers_freeze((Handlers* const*)&h[0], h.size(), status);
-}
-inline const MessageDef *Handlers::message_def() const {
-  return upb_handlers_msgdef(this);
-}
-inline bool Handlers::AddCleanup(void *p, upb_handlerfree *func) {
-  return upb_handlers_addcleanup(this, p, func);
-}
-inline bool Handlers::SetStartMessageHandler(
-    const Handlers::StartMessageHandler &handler) {
-  UPB_ASSERT(!handler.registered_);
-  handler.registered_ = true;
-  handler.AddCleanup(this);
-  return upb_handlers_setstartmsg(this, handler.handler_, &handler.attr_);
-}
-inline bool Handlers::SetEndMessageHandler(
-    const Handlers::EndMessageHandler &handler) {
-  UPB_ASSERT(!handler.registered_);
-  handler.registered_ = true;
-  handler.AddCleanup(this);
-  return upb_handlers_setendmsg(this, handler.handler_, &handler.attr_);
-}
-inline bool Handlers::SetStartStringHandler(const FieldDef *f,
-                                            const StartStringHandler &handler) {
-  UPB_ASSERT(!handler.registered_);
-  handler.registered_ = true;
-  handler.AddCleanup(this);
-  return upb_handlers_setstartstr(this, f, handler.handler_, &handler.attr_);
-}
-inline bool Handlers::SetEndStringHandler(const FieldDef *f,
-                                          const EndFieldHandler &handler) {
-  UPB_ASSERT(!handler.registered_);
-  handler.registered_ = true;
-  handler.AddCleanup(this);
-  return upb_handlers_setendstr(this, f, handler.handler_, &handler.attr_);
-}
-inline bool Handlers::SetStringHandler(const FieldDef *f,
-                                       const StringHandler& handler) {
-  UPB_ASSERT(!handler.registered_);
-  handler.registered_ = true;
-  handler.AddCleanup(this);
-  return upb_handlers_setstring(this, f, handler.handler_, &handler.attr_);
-}
-inline bool Handlers::SetStartSequenceHandler(
-    const FieldDef *f, const StartFieldHandler &handler) {
-  UPB_ASSERT(!handler.registered_);
-  handler.registered_ = true;
-  handler.AddCleanup(this);
-  return upb_handlers_setstartseq(this, f, handler.handler_, &handler.attr_);
-}
-inline bool Handlers::SetStartSubMessageHandler(
-    const FieldDef *f, const StartFieldHandler &handler) {
-  UPB_ASSERT(!handler.registered_);
-  handler.registered_ = true;
-  handler.AddCleanup(this);
-  return upb_handlers_setstartsubmsg(this, f, handler.handler_, &handler.attr_);
-}
-inline bool Handlers::SetEndSubMessageHandler(const FieldDef *f,
-                                              const EndFieldHandler &handler) {
-  UPB_ASSERT(!handler.registered_);
-  handler.registered_ = true;
-  handler.AddCleanup(this);
-  return upb_handlers_setendsubmsg(this, f, handler.handler_, &handler.attr_);
-}
-inline bool Handlers::SetEndSequenceHandler(const FieldDef *f,
-                                            const EndFieldHandler &handler) {
-  UPB_ASSERT(!handler.registered_);
-  handler.registered_ = true;
-  handler.AddCleanup(this);
-  return upb_handlers_setendseq(this, f, handler.handler_, &handler.attr_);
-}
-inline bool Handlers::SetSubHandlers(const FieldDef *f, const Handlers *sub) {
-  return upb_handlers_setsubhandlers(this, f, sub);
-}
-inline const Handlers *Handlers::GetSubHandlers(const FieldDef *f) const {
-  return upb_handlers_getsubhandlers(this, f);
-}
-inline const Handlers *Handlers::GetSubHandlers(Handlers::Selector sel) const {
-  return upb_handlers_getsubhandlers_sel(this, sel);
-}
-inline bool Handlers::GetSelector(const FieldDef *f, Handlers::Type type,
-                                  Handlers::Selector *s) {
-  return upb_handlers_getselector(f, type, s);
-}
-inline Handlers::Selector Handlers::GetEndSelector(Handlers::Selector start) {
-  return upb_handlers_getendselector(start);
-}
-inline Handlers::GenericFunction *Handlers::GetHandler(
-    Handlers::Selector selector) {
-  return upb_handlers_gethandler(this, selector);
-}
-inline const void *Handlers::GetHandlerData(Handlers::Selector selector) {
-  return upb_handlers_gethandlerdata(this, selector);
-}
-
-inline BytesHandler::BytesHandler() {
-  upb_byteshandler_init(this);
-}
-
-inline BytesHandler::~BytesHandler() {}
-
 }  /* namespace upb */
 
 #endif  /* __cplusplus */
@@ -5958,19 +5623,180 @@
 
 #ifdef __cplusplus
 namespace upb {
-class BufferSink;
-class BufferSource;
 class BytesSink;
 class Sink;
 }
 #endif
 
-UPB_DECLARE_TYPE(upb::BufferSink, upb_bufsink)
-UPB_DECLARE_TYPE(upb::BufferSource, upb_bufsrc)
-UPB_DECLARE_TYPE(upb::BytesSink, upb_bytessink)
-UPB_DECLARE_TYPE(upb::Sink, upb_sink)
+/* upb_sink *******************************************************************/
 
 #ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct {
+  const upb_handlers *handlers;
+  void *closure;
+} upb_sink;
+
+#define PUTVAL(type, ctype)                                           \
+  UPB_INLINE bool upb_sink_put##type(upb_sink s, upb_selector_t sel,  \
+                                     ctype val) {                     \
+    typedef upb_##type##_handlerfunc functype;                        \
+    functype *func;                                                   \
+    const void *hd;                                                   \
+    if (!s.handlers) return true;                                     \
+    func = (functype *)upb_handlers_gethandler(s.handlers, sel, &hd); \
+    if (!func) return true;                                           \
+    return func(s.closure, hd, val);                                  \
+  }
+
+PUTVAL(int32,  int32_t)
+PUTVAL(int64,  int64_t)
+PUTVAL(uint32, uint32_t)
+PUTVAL(uint64, uint64_t)
+PUTVAL(float,  float)
+PUTVAL(double, double)
+PUTVAL(bool,   bool)
+#undef PUTVAL
+
+UPB_INLINE void upb_sink_reset(upb_sink *s, const upb_handlers *h, void *c) {
+  s->handlers = h;
+  s->closure = c;
+}
+
+UPB_INLINE size_t upb_sink_putstring(upb_sink s, upb_selector_t sel,
+                                     const char *buf, size_t n,
+                                     const upb_bufhandle *handle) {
+  typedef upb_string_handlerfunc func;
+  func *handler;
+  const void *hd;
+  if (!s.handlers) return n;
+  handler = (func *)upb_handlers_gethandler(s.handlers, sel, &hd);
+
+  if (!handler) return n;
+  return handler(s.closure, hd, buf, n, handle);
+}
+
+UPB_INLINE bool upb_sink_putunknown(upb_sink s, const char *buf, size_t n) {
+  typedef upb_unknown_handlerfunc func;
+  func *handler;
+  const void *hd;
+  if (!s.handlers) return true;
+  handler =
+      (func *)upb_handlers_gethandler(s.handlers, UPB_UNKNOWN_SELECTOR, &hd);
+
+  if (!handler) return n;
+  return handler(s.closure, hd, buf, n);
+}
+
+UPB_INLINE bool upb_sink_startmsg(upb_sink s) {
+  typedef upb_startmsg_handlerfunc func;
+  func *startmsg;
+  const void *hd;
+  if (!s.handlers) return true;
+  startmsg =
+      (func *)upb_handlers_gethandler(s.handlers, UPB_STARTMSG_SELECTOR, &hd);
+
+  if (!startmsg) return true;
+  return startmsg(s.closure, hd);
+}
+
+UPB_INLINE bool upb_sink_endmsg(upb_sink s, upb_status *status) {
+  typedef upb_endmsg_handlerfunc func;
+  func *endmsg;
+  const void *hd;
+  if (!s.handlers) return true;
+  endmsg =
+      (func *)upb_handlers_gethandler(s.handlers, UPB_ENDMSG_SELECTOR, &hd);
+
+  if (!endmsg) return true;
+  return endmsg(s.closure, hd, status);
+}
+
+UPB_INLINE bool upb_sink_startseq(upb_sink s, upb_selector_t sel,
+                                  upb_sink *sub) {
+  typedef upb_startfield_handlerfunc func;
+  func *startseq;
+  const void *hd;
+  sub->closure = s.closure;
+  sub->handlers = s.handlers;
+  if (!s.handlers) return true;
+  startseq = (func*)upb_handlers_gethandler(s.handlers, sel, &hd);
+
+  if (!startseq) return true;
+  sub->closure = startseq(s.closure, hd);
+  return sub->closure ? true : false;
+}
+
+UPB_INLINE bool upb_sink_endseq(upb_sink s, upb_selector_t sel) {
+  typedef upb_endfield_handlerfunc func;
+  func *endseq;
+  const void *hd;
+  if (!s.handlers) return true;
+  endseq = (func*)upb_handlers_gethandler(s.handlers, sel, &hd);
+
+  if (!endseq) return true;
+  return endseq(s.closure, hd);
+}
+
+UPB_INLINE bool upb_sink_startstr(upb_sink s, upb_selector_t sel,
+                                  size_t size_hint, upb_sink *sub) {
+  typedef upb_startstr_handlerfunc func;
+  func *startstr;
+  const void *hd;
+  sub->closure = s.closure;
+  sub->handlers = s.handlers;
+  if (!s.handlers) return true;
+  startstr = (func*)upb_handlers_gethandler(s.handlers, sel, &hd);
+
+  if (!startstr) return true;
+  sub->closure = startstr(s.closure, hd, size_hint);
+  return sub->closure ? true : false;
+}
+
+UPB_INLINE bool upb_sink_endstr(upb_sink s, upb_selector_t sel) {
+  typedef upb_endfield_handlerfunc func;
+  func *endstr;
+  const void *hd;
+  if (!s.handlers) return true;
+  endstr = (func*)upb_handlers_gethandler(s.handlers, sel, &hd);
+
+  if (!endstr) return true;
+  return endstr(s.closure, hd);
+}
+
+UPB_INLINE bool upb_sink_startsubmsg(upb_sink s, upb_selector_t sel,
+                                     upb_sink *sub) {
+  typedef upb_startfield_handlerfunc func;
+  func *startsubmsg;
+  const void *hd;
+  sub->closure = s.closure;
+  if (!s.handlers) {
+    sub->handlers = NULL;
+    return true;
+  }
+  sub->handlers = upb_handlers_getsubhandlers_sel(s.handlers, sel);
+  startsubmsg = (func*)upb_handlers_gethandler(s.handlers, sel, &hd);
+
+  if (!startsubmsg) return true;
+  sub->closure = startsubmsg(s.closure, hd);
+  return sub->closure ? true : false;
+}
+
+UPB_INLINE bool upb_sink_endsubmsg(upb_sink s, upb_selector_t sel) {
+  typedef upb_endfield_handlerfunc func;
+  func *endsubmsg;
+  const void *hd;
+  if (!s.handlers) return true;
+  endsubmsg = (func*)upb_handlers_gethandler(s.handlers, sel, &hd);
+
+  if (!endsubmsg) return s.closure;
+  return endsubmsg(s.closure, hd);
+}
+
+#ifdef __cplusplus
+}  /* extern "C" */
 
 /* A upb::Sink is an object that binds a upb::Handlers object to some runtime
  * state.  It represents an endpoint to which data can be sent.
@@ -6013,20 +5839,39 @@
   /* Constructor with no initialization; must be Reset() before use. */
   Sink() {}
 
+  Sink(const Sink&) = default;
+  Sink& operator=(const Sink&) = default;
+
+  Sink(const upb_sink& sink) : sink_(sink) {}
+  Sink &operator=(const upb_sink &sink) {
+    sink_ = sink;
+    return *this;
+  }
+
+  upb_sink sink() { return sink_; }
+
   /* Constructs a new sink for the given frozen handlers and closure.
    *
    * TODO: once the Handlers know the expected closure type, verify that T
    * matches it. */
-  template <class T> Sink(const Handlers* handlers, T* closure);
+  template <class T> Sink(const upb_handlers* handlers, T* closure) {
+    Reset(handlers, closure);
+  }
+
+  upb_sink* ptr() { return &sink_; }
 
   /* Resets the value of the sink. */
-  template <class T> void Reset(const Handlers* handlers, T* closure);
+  template <class T> void Reset(const upb_handlers* handlers, T* closure) {
+    upb_sink_reset(&sink_, handlers, closure);
+  }
 
   /* Returns the top-level object that is bound to this sink.
    *
    * TODO: once the Handlers know the expected closure type, verify that T
    * matches it. */
-  template <class T> T* GetObject() const;
+  template <class T> T* GetObject() const {
+    return static_cast<T*>(sink_.closure);
+  }
 
   /* Functions for pushing data into the sink.
    *
@@ -6044,37 +5889,78 @@
    *   // ...
    *   sink->EndMessage(&status);
    *   sink->EndSubMessage(endsubmsg_selector); */
-  bool StartMessage();
-  bool EndMessage(Status* status);
+  bool StartMessage() { return upb_sink_startmsg(sink_); }
+  bool EndMessage(upb_status *status) {
+    return upb_sink_endmsg(sink_, status);
+  }
 
   /* Putting of individual values.  These work for both repeated and
    * non-repeated fields, but for repeated fields you must wrap them in
    * calls to StartSequence()/EndSequence(). */
-  bool PutInt32(Handlers::Selector s, int32_t val);
-  bool PutInt64(Handlers::Selector s, int64_t val);
-  bool PutUInt32(Handlers::Selector s, uint32_t val);
-  bool PutUInt64(Handlers::Selector s, uint64_t val);
-  bool PutFloat(Handlers::Selector s, float val);
-  bool PutDouble(Handlers::Selector s, double val);
-  bool PutBool(Handlers::Selector s, bool val);
+  bool PutInt32(HandlersPtr::Selector s, int32_t val) {
+    return upb_sink_putint32(sink_, s, val);
+  }
+
+  bool PutInt64(HandlersPtr::Selector s, int64_t val) {
+    return upb_sink_putint64(sink_, s, val);
+  }
+
+  bool PutUInt32(HandlersPtr::Selector s, uint32_t val) {
+    return upb_sink_putuint32(sink_, s, val);
+  }
+
+  bool PutUInt64(HandlersPtr::Selector s, uint64_t val) {
+    return upb_sink_putuint64(sink_, s, val);
+  }
+
+  bool PutFloat(HandlersPtr::Selector s, float val) {
+    return upb_sink_putfloat(sink_, s, val);
+  }
+
+  bool PutDouble(HandlersPtr::Selector s, double val) {
+    return upb_sink_putdouble(sink_, s, val);
+  }
+
+  bool PutBool(HandlersPtr::Selector s, bool val) {
+    return upb_sink_putbool(sink_, s, val);
+  }
 
   /* Putting of string/bytes values.  Each string can consist of zero or more
    * non-contiguous buffers of data.
    *
    * For StartString(), the function will write a sink for the string to "sub."
    * The sub-sink must be used for any/all PutStringBuffer() calls. */
-  bool StartString(Handlers::Selector s, size_t size_hint, Sink* sub);
-  size_t PutStringBuffer(Handlers::Selector s, const char *buf, size_t len,
-                         const BufferHandle *handle);
-  bool EndString(Handlers::Selector s);
+  bool StartString(HandlersPtr::Selector s, size_t size_hint, Sink* sub) {
+    upb_sink sub_c;
+    bool ret = upb_sink_startstr(sink_, s, size_hint, &sub_c);
+    *sub = sub_c;
+    return ret;
+  }
+
+  size_t PutStringBuffer(HandlersPtr::Selector s, const char *buf, size_t len,
+                         const upb_bufhandle *handle) {
+    return upb_sink_putstring(sink_, s, buf, len, handle);
+  }
+
+  bool EndString(HandlersPtr::Selector s) {
+    return upb_sink_endstr(sink_, s);
+  }
 
   /* For submessage fields.
    *
    * For StartSubMessage(), the function will write a sink for the string to
    * "sub." The sub-sink must be used for any/all handlers called within the
    * submessage. */
-  bool StartSubMessage(Handlers::Selector s, Sink* sub);
-  bool EndSubMessage(Handlers::Selector s);
+  bool StartSubMessage(HandlersPtr::Selector s, Sink* sub) {
+    upb_sink sub_c;
+    bool ret = upb_sink_startsubmsg(sink_, s, &sub_c);
+    *sub = sub_c;
+    return ret;
+  }
+
+  bool EndSubMessage(HandlersPtr::Selector s) {
+    return upb_sink_endsubmsg(sink_, s);
+  }
 
   /* For repeated fields of any type, the sequence of values must be wrapped in
    * these calls.
@@ -6082,1728 +5968,163 @@
    * For StartSequence(), the function will write a sink for the string to
    * "sub." The sub-sink must be used for any/all handlers called within the
    * sequence. */
-  bool StartSequence(Handlers::Selector s, Sink* sub);
-  bool EndSequence(Handlers::Selector s);
+  bool StartSequence(HandlersPtr::Selector s, Sink* sub) {
+    upb_sink sub_c;
+    bool ret = upb_sink_startseq(sink_, s, &sub_c);
+    *sub = sub_c;
+    return ret;
+  }
+
+  bool EndSequence(HandlersPtr::Selector s) {
+    return upb_sink_endseq(sink_, s);
+  }
 
   /* Copy and assign specifically allowed.
    * We don't even bother making these members private because so many
    * functions need them and this is mainly just a dumb data container anyway.
    */
-#else
-struct upb_sink {
-#endif
-  const upb_handlers *handlers;
-  void *closure;
+
+ private:
+  upb_sink sink_;
 };
 
-#ifdef __cplusplus
-class upb::BytesSink {
- public:
-  BytesSink() {}
+#endif  /* __cplusplus */
 
-  /* Constructs a new sink for the given frozen handlers and closure.
-   *
-   * TODO(haberman): once the Handlers know the expected closure type, verify
-   * that T matches it. */
-  template <class T> BytesSink(const BytesHandler* handler, T* closure);
+/* upb_bytessink **************************************************************/
 
-  /* Resets the value of the sink. */
-  template <class T> void Reset(const BytesHandler* handler, T* closure);
-
-  bool Start(size_t size_hint, void **subc);
-  size_t PutBuffer(void *subc, const char *buf, size_t len,
-                   const BufferHandle *handle);
-  bool End();
-#else
-struct upb_bytessink {
-#endif
+typedef struct {
   const upb_byteshandler *handler;
   void *closure;
-};
+} upb_bytessink ;
 
-#ifdef __cplusplus
-
-/* A class for pushing a flat buffer of data to a BytesSink.
- * You can construct an instance of this to get a resumable source,
- * or just call the static PutBuffer() to do a non-resumable push all in one
- * go. */
-class upb::BufferSource {
- public:
-  BufferSource();
-  BufferSource(const char* buf, size_t len, BytesSink* sink);
-
-  /* Returns true if the entire buffer was pushed successfully.  Otherwise the
-   * next call to PutNext() will resume where the previous one left off.
-   * TODO(haberman): implement this. */
-  bool PutNext();
-
-  /* A static version; with this version is it not possible to resume in the
-   * case of failure or a partially-consumed buffer. */
-  static bool PutBuffer(const char* buf, size_t len, BytesSink* sink);
-
-  template <class T> static bool PutBuffer(const T& str, BytesSink* sink) {
-    return PutBuffer(str.c_str(), str.size(), sink);
-  }
-#else
-struct upb_bufsrc {
-  char dummy;
-#endif
-};
-
-UPB_BEGIN_EXTERN_C
-
-/* A class for accumulating output string data in a flat buffer. */
-
-upb_bufsink *upb_bufsink_new(upb_env *env);
-void upb_bufsink_free(upb_bufsink *sink);
-upb_bytessink *upb_bufsink_sink(upb_bufsink *sink);
-const char *upb_bufsink_getdata(const upb_bufsink *sink, size_t *len);
-
-/* Inline definitions. */
-
-UPB_INLINE void upb_bytessink_reset(upb_bytessink *s, const upb_byteshandler *h,
+UPB_INLINE void upb_bytessink_reset(upb_bytessink* s, const upb_byteshandler *h,
                                     void *closure) {
   s->handler = h;
   s->closure = closure;
 }
 
-UPB_INLINE bool upb_bytessink_start(upb_bytessink *s, size_t size_hint,
+UPB_INLINE bool upb_bytessink_start(upb_bytessink s, size_t size_hint,
                                     void **subc) {
   typedef upb_startstr_handlerfunc func;
   func *start;
-  *subc = s->closure;
-  if (!s->handler) return true;
-  start = (func *)s->handler->table[UPB_STARTSTR_SELECTOR].func;
+  *subc = s.closure;
+  if (!s.handler) return true;
+  start = (func *)s.handler->table[UPB_STARTSTR_SELECTOR].func;
 
   if (!start) return true;
-  *subc = start(s->closure, upb_handlerattr_handlerdata(
-                                &s->handler->table[UPB_STARTSTR_SELECTOR].attr),
+  *subc = start(s.closure,
+                s.handler->table[UPB_STARTSTR_SELECTOR].attr.handler_data,
                 size_hint);
   return *subc != NULL;
 }
 
-UPB_INLINE size_t upb_bytessink_putbuf(upb_bytessink *s, void *subc,
+UPB_INLINE size_t upb_bytessink_putbuf(upb_bytessink s, void *subc,
                                        const char *buf, size_t size,
                                        const upb_bufhandle* handle) {
   typedef upb_string_handlerfunc func;
   func *putbuf;
-  if (!s->handler) return true;
-  putbuf = (func *)s->handler->table[UPB_STRING_SELECTOR].func;
+  if (!s.handler) return true;
+  putbuf = (func *)s.handler->table[UPB_STRING_SELECTOR].func;
 
   if (!putbuf) return true;
-  return putbuf(subc, upb_handlerattr_handlerdata(
-                          &s->handler->table[UPB_STRING_SELECTOR].attr),
+  return putbuf(subc, s.handler->table[UPB_STRING_SELECTOR].attr.handler_data,
                 buf, size, handle);
 }
 
-UPB_INLINE bool upb_bytessink_end(upb_bytessink *s) {
+UPB_INLINE bool upb_bytessink_end(upb_bytessink s) {
   typedef upb_endfield_handlerfunc func;
   func *end;
-  if (!s->handler) return true;
-  end = (func *)s->handler->table[UPB_ENDSTR_SELECTOR].func;
+  if (!s.handler) return true;
+  end = (func *)s.handler->table[UPB_ENDSTR_SELECTOR].func;
 
   if (!end) return true;
-  return end(s->closure,
-             upb_handlerattr_handlerdata(
-                 &s->handler->table[UPB_ENDSTR_SELECTOR].attr));
+  return end(s.closure,
+             s.handler->table[UPB_ENDSTR_SELECTOR].attr.handler_data);
 }
 
-bool upb_bufsrc_putbuf(const char *buf, size_t len, upb_bytessink *sink);
-
-#define PUTVAL(type, ctype)                                                    \
-  UPB_INLINE bool upb_sink_put##type(upb_sink *s, upb_selector_t sel,          \
-                                     ctype val) {                              \
-    typedef upb_##type##_handlerfunc functype;                                 \
-    functype *func;                                                            \
-    const void *hd;                                                            \
-    if (!s->handlers) return true;                                             \
-    func = (functype *)upb_handlers_gethandler(s->handlers, sel);              \
-    if (!func) return true;                                                    \
-    hd = upb_handlers_gethandlerdata(s->handlers, sel);                        \
-    return func(s->closure, hd, val);                                          \
-  }
-
-PUTVAL(int32,  int32_t)
-PUTVAL(int64,  int64_t)
-PUTVAL(uint32, uint32_t)
-PUTVAL(uint64, uint64_t)
-PUTVAL(float,  float)
-PUTVAL(double, double)
-PUTVAL(bool,   bool)
-#undef PUTVAL
-
-UPB_INLINE void upb_sink_reset(upb_sink *s, const upb_handlers *h, void *c) {
-  s->handlers = h;
-  s->closure = c;
-}
-
-UPB_INLINE size_t upb_sink_putstring(upb_sink *s, upb_selector_t sel,
-                                     const char *buf, size_t n,
-                                     const upb_bufhandle *handle) {
-  typedef upb_string_handlerfunc func;
-  func *handler;
-  const void *hd;
-  if (!s->handlers) return n;
-  handler = (func *)upb_handlers_gethandler(s->handlers, sel);
-
-  if (!handler) return n;
-  hd = upb_handlers_gethandlerdata(s->handlers, sel);
-  return handler(s->closure, hd, buf, n, handle);
-}
-
-UPB_INLINE bool upb_sink_putunknown(upb_sink *s, const char *buf, size_t n) {
-  typedef upb_unknown_handlerfunc func;
-  func *handler;
-  const void *hd;
-  if (!s->handlers) return true;
-  handler = (func *)upb_handlers_gethandler(s->handlers, UPB_UNKNOWN_SELECTOR);
-
-  if (!handler) return n;
-  hd = upb_handlers_gethandlerdata(s->handlers, UPB_UNKNOWN_SELECTOR);
-  return handler(s->closure, hd, buf, n);
-}
-
-UPB_INLINE bool upb_sink_startmsg(upb_sink *s) {
-  typedef upb_startmsg_handlerfunc func;
-  func *startmsg;
-  const void *hd;
-  if (!s->handlers) return true;
-  startmsg = (func*)upb_handlers_gethandler(s->handlers, UPB_STARTMSG_SELECTOR);
-
-  if (!startmsg) return true;
-  hd = upb_handlers_gethandlerdata(s->handlers, UPB_STARTMSG_SELECTOR);
-  return startmsg(s->closure, hd);
-}
-
-UPB_INLINE bool upb_sink_endmsg(upb_sink *s, upb_status *status) {
-  typedef upb_endmsg_handlerfunc func;
-  func *endmsg;
-  const void *hd;
-  if (!s->handlers) return true;
-  endmsg = (func *)upb_handlers_gethandler(s->handlers, UPB_ENDMSG_SELECTOR);
-
-  if (!endmsg) return true;
-  hd = upb_handlers_gethandlerdata(s->handlers, UPB_ENDMSG_SELECTOR);
-  return endmsg(s->closure, hd, status);
-}
-
-UPB_INLINE bool upb_sink_startseq(upb_sink *s, upb_selector_t sel,
-                                  upb_sink *sub) {
-  typedef upb_startfield_handlerfunc func;
-  func *startseq;
-  const void *hd;
-  sub->closure = s->closure;
-  sub->handlers = s->handlers;
-  if (!s->handlers) return true;
-  startseq = (func*)upb_handlers_gethandler(s->handlers, sel);
-
-  if (!startseq) return true;
-  hd = upb_handlers_gethandlerdata(s->handlers, sel);
-  sub->closure = startseq(s->closure, hd);
-  return sub->closure ? true : false;
-}
-
-UPB_INLINE bool upb_sink_endseq(upb_sink *s, upb_selector_t sel) {
-  typedef upb_endfield_handlerfunc func;
-  func *endseq;
-  const void *hd;
-  if (!s->handlers) return true;
-  endseq = (func*)upb_handlers_gethandler(s->handlers, sel);
-
-  if (!endseq) return true;
-  hd = upb_handlers_gethandlerdata(s->handlers, sel);
-  return endseq(s->closure, hd);
-}
-
-UPB_INLINE bool upb_sink_startstr(upb_sink *s, upb_selector_t sel,
-                                  size_t size_hint, upb_sink *sub) {
-  typedef upb_startstr_handlerfunc func;
-  func *startstr;
-  const void *hd;
-  sub->closure = s->closure;
-  sub->handlers = s->handlers;
-  if (!s->handlers) return true;
-  startstr = (func*)upb_handlers_gethandler(s->handlers, sel);
-
-  if (!startstr) return true;
-  hd = upb_handlers_gethandlerdata(s->handlers, sel);
-  sub->closure = startstr(s->closure, hd, size_hint);
-  return sub->closure ? true : false;
-}
-
-UPB_INLINE bool upb_sink_endstr(upb_sink *s, upb_selector_t sel) {
-  typedef upb_endfield_handlerfunc func;
-  func *endstr;
-  const void *hd;
-  if (!s->handlers) return true;
-  endstr = (func*)upb_handlers_gethandler(s->handlers, sel);
-
-  if (!endstr) return true;
-  hd = upb_handlers_gethandlerdata(s->handlers, sel);
-  return endstr(s->closure, hd);
-}
-
-UPB_INLINE bool upb_sink_startsubmsg(upb_sink *s, upb_selector_t sel,
-                                     upb_sink *sub) {
-  typedef upb_startfield_handlerfunc func;
-  func *startsubmsg;
-  const void *hd;
-  sub->closure = s->closure;
-  if (!s->handlers) {
-    sub->handlers = NULL;
-    return true;
-  }
-  sub->handlers = upb_handlers_getsubhandlers_sel(s->handlers, sel);
-  startsubmsg = (func*)upb_handlers_gethandler(s->handlers, sel);
-
-  if (!startsubmsg) return true;
-  hd = upb_handlers_gethandlerdata(s->handlers, sel);
-  sub->closure = startsubmsg(s->closure, hd);
-  return sub->closure ? true : false;
-}
-
-UPB_INLINE bool upb_sink_endsubmsg(upb_sink *s, upb_selector_t sel) {
-  typedef upb_endfield_handlerfunc func;
-  func *endsubmsg;
-  const void *hd;
-  if (!s->handlers) return true;
-  endsubmsg = (func*)upb_handlers_gethandler(s->handlers, sel);
-
-  if (!endsubmsg) return s->closure;
-  hd = upb_handlers_gethandlerdata(s->handlers, sel);
-  return endsubmsg(s->closure, hd);
-}
-
-UPB_END_EXTERN_C
-
 #ifdef __cplusplus
 
+class upb::BytesSink {
+ public:
+  BytesSink() {}
+
+  BytesSink(const BytesSink&) = default;
+  BytesSink& operator=(const BytesSink&) = default;
+
+  BytesSink(const upb_bytessink& sink) : sink_(sink) {}
+  BytesSink &operator=(const upb_bytessink &sink) {
+    sink_ = sink;
+    return *this;
+  }
+
+  upb_bytessink sink() { return sink_; }
+
+  /* Constructs a new sink for the given frozen handlers and closure.
+   *
+   * TODO(haberman): once the Handlers know the expected closure type, verify
+   * that T matches it. */
+  template <class T> BytesSink(const upb_byteshandler* handler, T* closure) {
+    upb_bytessink_reset(sink_, handler, closure);
+  }
+
+  /* Resets the value of the sink. */
+  template <class T> void Reset(const upb_byteshandler* handler, T* closure) {
+    upb_bytessink_reset(&sink_, handler, closure);
+  }
+
+  bool Start(size_t size_hint, void **subc) {
+    return upb_bytessink_start(sink_, size_hint, subc);
+  }
+
+  size_t PutBuffer(void *subc, const char *buf, size_t len,
+                   const upb_bufhandle *handle) {
+    return upb_bytessink_putbuf(sink_, subc, buf, len, handle);
+  }
+
+  bool End() {
+    return upb_bytessink_end(sink_);
+  }
+
+ private:
+  upb_bytessink sink_;
+};
+
+#endif  /* __cplusplus */
+
+/* upb_bufsrc *****************************************************************/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+bool upb_bufsrc_putbuf(const char *buf, size_t len, upb_bytessink sink);
+
+#ifdef __cplusplus
+}  /* extern "C" */
+
 namespace upb {
-
-template <class T> Sink::Sink(const Handlers* handlers, T* closure) {
-  upb_sink_reset(this, handlers, closure);
+template <class T> bool PutBuffer(const T& str, BytesSink sink) {
+  return upb_bufsrc_putbuf(str.data(), str.size(), sink.sink());
 }
-template <class T>
-inline void Sink::Reset(const Handlers* handlers, T* closure) {
-  upb_sink_reset(this, handlers, closure);
-}
-inline bool Sink::StartMessage() {
-  return upb_sink_startmsg(this);
-}
-inline bool Sink::EndMessage(Status* status) {
-  return upb_sink_endmsg(this, status);
-}
-inline bool Sink::PutInt32(Handlers::Selector sel, int32_t val) {
-  return upb_sink_putint32(this, sel, val);
-}
-inline bool Sink::PutInt64(Handlers::Selector sel, int64_t val) {
-  return upb_sink_putint64(this, sel, val);
-}
-inline bool Sink::PutUInt32(Handlers::Selector sel, uint32_t val) {
-  return upb_sink_putuint32(this, sel, val);
-}
-inline bool Sink::PutUInt64(Handlers::Selector sel, uint64_t val) {
-  return upb_sink_putuint64(this, sel, val);
-}
-inline bool Sink::PutFloat(Handlers::Selector sel, float val) {
-  return upb_sink_putfloat(this, sel, val);
-}
-inline bool Sink::PutDouble(Handlers::Selector sel, double val) {
-  return upb_sink_putdouble(this, sel, val);
-}
-inline bool Sink::PutBool(Handlers::Selector sel, bool val) {
-  return upb_sink_putbool(this, sel, val);
-}
-inline bool Sink::StartString(Handlers::Selector sel, size_t size_hint,
-                              Sink *sub) {
-  return upb_sink_startstr(this, sel, size_hint, sub);
-}
-inline size_t Sink::PutStringBuffer(Handlers::Selector sel, const char *buf,
-                                    size_t len, const BufferHandle* handle) {
-  return upb_sink_putstring(this, sel, buf, len, handle);
-}
-inline bool Sink::EndString(Handlers::Selector sel) {
-  return upb_sink_endstr(this, sel);
-}
-inline bool Sink::StartSubMessage(Handlers::Selector sel, Sink* sub) {
-  return upb_sink_startsubmsg(this, sel, sub);
-}
-inline bool Sink::EndSubMessage(Handlers::Selector sel) {
-  return upb_sink_endsubmsg(this, sel);
-}
-inline bool Sink::StartSequence(Handlers::Selector sel, Sink* sub) {
-  return upb_sink_startseq(this, sel, sub);
-}
-inline bool Sink::EndSequence(Handlers::Selector sel) {
-  return upb_sink_endseq(this, sel);
 }
 
-template <class T>
-BytesSink::BytesSink(const BytesHandler* handler, T* closure) {
-  Reset(handler, closure);
-}
-
-template <class T>
-void BytesSink::Reset(const BytesHandler *handler, T *closure) {
-  upb_bytessink_reset(this, handler, closure);
-}
-inline bool BytesSink::Start(size_t size_hint, void **subc) {
-  return upb_bytessink_start(this, size_hint, subc);
-}
-inline size_t BytesSink::PutBuffer(void *subc, const char *buf, size_t len,
-                                   const BufferHandle *handle) {
-  return upb_bytessink_putbuf(this, subc, buf, len, handle);
-}
-inline bool BytesSink::End() {
-  return upb_bytessink_end(this);
-}
-
-inline bool BufferSource::PutBuffer(const char *buf, size_t len,
-                                    BytesSink *sink) {
-  return upb_bufsrc_putbuf(buf, len, sink);
-}
-
-}  /* namespace upb */
-#endif
+#endif  /* __cplusplus */
 
 #endif
 
-#ifdef __cplusplus
-
-namespace upb {
-class Array;
-class Map;
-class MapIterator;
-class MessageLayout;
-}
-
-#endif
-
-UPB_DECLARE_TYPE(upb::Array, upb_array)
-UPB_DECLARE_TYPE(upb::Map, upb_map)
-UPB_DECLARE_TYPE(upb::MapIterator, upb_mapiter)
-
-/* TODO(haberman): C++ accessors */
-
-UPB_BEGIN_EXTERN_C
-
-typedef void upb_msg;
-
-
-/** upb_msglayout *************************************************************/
-
-/* upb_msglayout represents the memory layout of a given upb_msgdef.  The
- * members are public so generated code can initialize them, but users MUST NOT
- * read or write any of its members. */
-
-typedef struct {
-  uint32_t number;
-  uint16_t offset;
-  int16_t presence;      /* If >0, hasbit_index+1.  If <0, oneof_index+1. */
-  uint16_t submsg_index;  /* undefined if descriptortype != MESSAGE or GROUP. */
-  uint8_t descriptortype;
-  uint8_t label;
-} upb_msglayout_field;
-
-typedef struct upb_msglayout {
-  const struct upb_msglayout *const* submsgs;
-  const upb_msglayout_field *fields;
-  /* Must be aligned to sizeof(void*).  Doesn't include internal members like
-   * unknown fields, extension dict, pointer to msglayout, etc. */
-  uint16_t size;
-  uint16_t field_count;
-  bool extendable;
-} upb_msglayout;
-
-
-/** upb_stringview ************************************************************/
-
-typedef struct {
-  const char *data;
-  size_t size;
-} upb_stringview;
-
-UPB_INLINE upb_stringview upb_stringview_make(const char *data, size_t size) {
-  upb_stringview ret;
-  ret.data = data;
-  ret.size = size;
-  return ret;
-}
-
-#define UPB_STRINGVIEW_INIT(ptr, len) {ptr, len}
-
-
-/** upb_msgval ****************************************************************/
-
-/* A union representing all possible protobuf values.  Used for generic get/set
- * operations. */
-
-typedef union {
-  bool b;
-  float flt;
-  double dbl;
-  int32_t i32;
-  int64_t i64;
-  uint32_t u32;
-  uint64_t u64;
-  const upb_map* map;
-  const upb_msg* msg;
-  const upb_array* arr;
-  const void* ptr;
-  upb_stringview str;
-} upb_msgval;
-
-#define ACCESSORS(name, membername, ctype) \
-  UPB_INLINE ctype upb_msgval_get ## name(upb_msgval v) { \
-    return v.membername; \
-  } \
-  UPB_INLINE void upb_msgval_set ## name(upb_msgval *v, ctype cval) { \
-    v->membername = cval; \
-  } \
-  UPB_INLINE upb_msgval upb_msgval_ ## name(ctype v) { \
-    upb_msgval ret; \
-    ret.membername = v; \
-    return ret; \
-  }
-
-ACCESSORS(bool,   b,   bool)
-ACCESSORS(float,  flt, float)
-ACCESSORS(double, dbl, double)
-ACCESSORS(int32,  i32, int32_t)
-ACCESSORS(int64,  i64, int64_t)
-ACCESSORS(uint32, u32, uint32_t)
-ACCESSORS(uint64, u64, uint64_t)
-ACCESSORS(map,    map, const upb_map*)
-ACCESSORS(msg,    msg, const upb_msg*)
-ACCESSORS(ptr,    ptr, const void*)
-ACCESSORS(arr,    arr, const upb_array*)
-ACCESSORS(str,    str, upb_stringview)
-
-#undef ACCESSORS
-
-UPB_INLINE upb_msgval upb_msgval_makestr(const char *data, size_t size) {
-  return upb_msgval_str(upb_stringview_make(data, size));
-}
-
-
-/** upb_msg *******************************************************************/
-
-/* A upb_msg represents a protobuf message.  It always corresponds to a specific
- * upb_msglayout, which describes how it is laid out in memory.  */
-
-/* Creates a new message of the given type/layout in this arena. */
-upb_msg *upb_msg_new(const upb_msglayout *l, upb_arena *a);
-
-/* Returns the arena for the given message. */
-upb_arena *upb_msg_arena(const upb_msg *msg);
-
-void upb_msg_addunknown(upb_msg *msg, const char *data, size_t len);
-const char *upb_msg_getunknown(const upb_msg *msg, size_t *len);
-
-/* Read-only message API.  Can be safely called by anyone. */
-
-/* Returns the value associated with this field:
- *   - for scalar fields (including strings), the value directly.
- *   - return upb_msg*, or upb_map* for msg/map.
- *     If the field is unset for these field types, returns NULL.
- *
- * TODO(haberman): should we let users store cached array/map/msg
- * pointers here for fields that are unset?  Could be useful for the
- * strongly-owned submessage model (ie. generated C API that doesn't use
- * arenas).
- */
-upb_msgval upb_msg_get(const upb_msg *msg,
-                       int field_index,
-                       const upb_msglayout *l);
-
-/* May only be called for fields where upb_fielddef_haspresence(f) == true. */
-bool upb_msg_has(const upb_msg *msg,
-                 int field_index,
-                 const upb_msglayout *l);
-
-/* Mutable message API.  May only be called by the owner of the message who
- * knows its ownership scheme and how to keep it consistent. */
-
-/* Sets the given field to the given value.  Does not perform any memory
- * management: if you overwrite a pointer to a msg/array/map/string without
- * cleaning it up (or using an arena) it will leak.
- */
-void upb_msg_set(upb_msg *msg,
-                 int field_index,
-                 upb_msgval val,
-                 const upb_msglayout *l);
-
-/* For a primitive field, set it back to its default. For repeated, string, and
- * submessage fields set it back to NULL.  This could involve releasing some
- * internal memory (for example, from an extension dictionary), but it is not
- * recursive in any way and will not recover any memory that may be used by
- * arrays/maps/strings/msgs that this field may have pointed to.
- */
-bool upb_msg_clearfield(upb_msg *msg,
-                        int field_index,
-                        const upb_msglayout *l);
-
-/* TODO(haberman): copyfrom()/mergefrom()? */
-
-
-/** upb_array *****************************************************************/
-
-/* A upb_array stores data for a repeated field.  The memory management
- * semantics are the same as upb_msg.  A upb_array allocates dynamic
- * memory internally for the array elements. */
-
-upb_array *upb_array_new(upb_fieldtype_t type, upb_arena *a);
-upb_fieldtype_t upb_array_type(const upb_array *arr);
-
-/* Read-only interface.  Safe for anyone to call. */
-
-size_t upb_array_size(const upb_array *arr);
-upb_msgval upb_array_get(const upb_array *arr, size_t i);
-
-/* Write interface.  May only be called by the message's owner who can enforce
- * its memory management invariants. */
-
-bool upb_array_set(upb_array *arr, size_t i, upb_msgval val);
-
-
-/** upb_map *******************************************************************/
-
-/* A upb_map stores data for a map field.  The memory management semantics are
- * the same as upb_msg, with one notable exception.  upb_map will internally
- * store a copy of all string keys, but *not* any string values or submessages.
- * So you must ensure that any string or message values outlive the map, and you
- * must delete them manually when they are no longer required. */
-
-upb_map *upb_map_new(upb_fieldtype_t ktype, upb_fieldtype_t vtype,
-                     upb_arena *a);
-
-/* Read-only interface.  Safe for anyone to call. */
-
-size_t upb_map_size(const upb_map *map);
-upb_fieldtype_t upb_map_keytype(const upb_map *map);
-upb_fieldtype_t upb_map_valuetype(const upb_map *map);
-bool upb_map_get(const upb_map *map, upb_msgval key, upb_msgval *val);
-
-/* Write interface.  May only be called by the message's owner who can enforce
- * its memory management invariants. */
-
-/* Sets or overwrites an entry in the map.  Return value indicates whether
- * the operation succeeded or failed with OOM, and also whether an existing
- * key was replaced or not. */
-bool upb_map_set(upb_map *map,
-                 upb_msgval key, upb_msgval val,
-                 upb_msgval *valremoved);
-
-/* Deletes an entry in the map.  Returns true if the key was present. */
-bool upb_map_del(upb_map *map, upb_msgval key);
-
-
-/** upb_mapiter ***************************************************************/
-
-/* For iterating over a map.  Map iterators are invalidated by mutations to the
- * map, but an invalidated iterator will never return junk or crash the process.
- * An invalidated iterator may return entries that were already returned though,
- * and if you keep invalidating the iterator during iteration, the program may
- * enter an infinite loop. */
-
-size_t upb_mapiter_sizeof();
-
-void upb_mapiter_begin(upb_mapiter *i, const upb_map *t);
-upb_mapiter *upb_mapiter_new(const upb_map *t, upb_alloc *a);
-void upb_mapiter_free(upb_mapiter *i, upb_alloc *a);
-void upb_mapiter_next(upb_mapiter *i);
-bool upb_mapiter_done(const upb_mapiter *i);
-
-upb_msgval upb_mapiter_key(const upb_mapiter *i);
-upb_msgval upb_mapiter_value(const upb_mapiter *i);
-void upb_mapiter_setdone(upb_mapiter *i);
-bool upb_mapiter_isequal(const upb_mapiter *i1, const upb_mapiter *i2);
-
-UPB_END_EXTERN_C
-
-#endif /* UPB_MSG_H_ */
-/* This file was generated by upbc (the upb compiler) from the input
- * file:
- *
- *     google/protobuf/descriptor.proto
- *
- * Do not edit -- your changes will be discarded when the file is
- * regenerated. */
-
-#ifndef GOOGLE_PROTOBUF_DESCRIPTOR_PROTO_UPB_H_
-#define GOOGLE_PROTOBUF_DESCRIPTOR_PROTO_UPB_H_
-
-
-/*
-** upb_decode: parsing into a upb_msg using a upb_msglayout.
-*/
-
-#ifndef UPB_DECODE_H_
-#define UPB_DECODE_H_
-
-
-UPB_BEGIN_EXTERN_C
-
-bool upb_decode(upb_stringview buf, upb_msg *msg, const upb_msglayout *l);
-
-UPB_END_EXTERN_C
-
-#endif  /* UPB_DECODE_H_ */
-/*
-** upb_encode: parsing into a upb_msg using a upb_msglayout.
-*/
-
-#ifndef UPB_ENCODE_H_
-#define UPB_ENCODE_H_
-
-
-UPB_BEGIN_EXTERN_C
-
-char *upb_encode(const void *msg, const upb_msglayout *l, upb_arena *arena,
-                 size_t *size);
-
-UPB_END_EXTERN_C
-
-#endif  /* UPB_ENCODE_H_ */
-UPB_BEGIN_EXTERN_C
-
-struct google_protobuf_FileDescriptorSet;
-struct google_protobuf_FileDescriptorProto;
-struct google_protobuf_DescriptorProto;
-struct google_protobuf_DescriptorProto_ExtensionRange;
-struct google_protobuf_DescriptorProto_ReservedRange;
-struct google_protobuf_ExtensionRangeOptions;
-struct google_protobuf_FieldDescriptorProto;
-struct google_protobuf_OneofDescriptorProto;
-struct google_protobuf_EnumDescriptorProto;
-struct google_protobuf_EnumDescriptorProto_EnumReservedRange;
-struct google_protobuf_EnumValueDescriptorProto;
-struct google_protobuf_ServiceDescriptorProto;
-struct google_protobuf_MethodDescriptorProto;
-struct google_protobuf_FileOptions;
-struct google_protobuf_MessageOptions;
-struct google_protobuf_FieldOptions;
-struct google_protobuf_OneofOptions;
-struct google_protobuf_EnumOptions;
-struct google_protobuf_EnumValueOptions;
-struct google_protobuf_ServiceOptions;
-struct google_protobuf_MethodOptions;
-struct google_protobuf_UninterpretedOption;
-struct google_protobuf_UninterpretedOption_NamePart;
-struct google_protobuf_SourceCodeInfo;
-struct google_protobuf_SourceCodeInfo_Location;
-struct google_protobuf_GeneratedCodeInfo;
-struct google_protobuf_GeneratedCodeInfo_Annotation;
-typedef struct google_protobuf_FileDescriptorSet google_protobuf_FileDescriptorSet;
-typedef struct google_protobuf_FileDescriptorProto google_protobuf_FileDescriptorProto;
-typedef struct google_protobuf_DescriptorProto google_protobuf_DescriptorProto;
-typedef struct google_protobuf_DescriptorProto_ExtensionRange google_protobuf_DescriptorProto_ExtensionRange;
-typedef struct google_protobuf_DescriptorProto_ReservedRange google_protobuf_DescriptorProto_ReservedRange;
-typedef struct google_protobuf_ExtensionRangeOptions google_protobuf_ExtensionRangeOptions;
-typedef struct google_protobuf_FieldDescriptorProto google_protobuf_FieldDescriptorProto;
-typedef struct google_protobuf_OneofDescriptorProto google_protobuf_OneofDescriptorProto;
-typedef struct google_protobuf_EnumDescriptorProto google_protobuf_EnumDescriptorProto;
-typedef struct google_protobuf_EnumDescriptorProto_EnumReservedRange google_protobuf_EnumDescriptorProto_EnumReservedRange;
-typedef struct google_protobuf_EnumValueDescriptorProto google_protobuf_EnumValueDescriptorProto;
-typedef struct google_protobuf_ServiceDescriptorProto google_protobuf_ServiceDescriptorProto;
-typedef struct google_protobuf_MethodDescriptorProto google_protobuf_MethodDescriptorProto;
-typedef struct google_protobuf_FileOptions google_protobuf_FileOptions;
-typedef struct google_protobuf_MessageOptions google_protobuf_MessageOptions;
-typedef struct google_protobuf_FieldOptions google_protobuf_FieldOptions;
-typedef struct google_protobuf_OneofOptions google_protobuf_OneofOptions;
-typedef struct google_protobuf_EnumOptions google_protobuf_EnumOptions;
-typedef struct google_protobuf_EnumValueOptions google_protobuf_EnumValueOptions;
-typedef struct google_protobuf_ServiceOptions google_protobuf_ServiceOptions;
-typedef struct google_protobuf_MethodOptions google_protobuf_MethodOptions;
-typedef struct google_protobuf_UninterpretedOption google_protobuf_UninterpretedOption;
-typedef struct google_protobuf_UninterpretedOption_NamePart google_protobuf_UninterpretedOption_NamePart;
-typedef struct google_protobuf_SourceCodeInfo google_protobuf_SourceCodeInfo;
-typedef struct google_protobuf_SourceCodeInfo_Location google_protobuf_SourceCodeInfo_Location;
-typedef struct google_protobuf_GeneratedCodeInfo google_protobuf_GeneratedCodeInfo;
-typedef struct google_protobuf_GeneratedCodeInfo_Annotation google_protobuf_GeneratedCodeInfo_Annotation;
-
-/* Enums */
-
-typedef enum {
-  google_protobuf_FieldDescriptorProto_LABEL_OPTIONAL = 1,
-  google_protobuf_FieldDescriptorProto_LABEL_REQUIRED = 2,
-  google_protobuf_FieldDescriptorProto_LABEL_REPEATED = 3
-} google_protobuf_FieldDescriptorProto_Label;
-
-typedef enum {
-  google_protobuf_FieldDescriptorProto_TYPE_DOUBLE = 1,
-  google_protobuf_FieldDescriptorProto_TYPE_FLOAT = 2,
-  google_protobuf_FieldDescriptorProto_TYPE_INT64 = 3,
-  google_protobuf_FieldDescriptorProto_TYPE_UINT64 = 4,
-  google_protobuf_FieldDescriptorProto_TYPE_INT32 = 5,
-  google_protobuf_FieldDescriptorProto_TYPE_FIXED64 = 6,
-  google_protobuf_FieldDescriptorProto_TYPE_FIXED32 = 7,
-  google_protobuf_FieldDescriptorProto_TYPE_BOOL = 8,
-  google_protobuf_FieldDescriptorProto_TYPE_STRING = 9,
-  google_protobuf_FieldDescriptorProto_TYPE_GROUP = 10,
-  google_protobuf_FieldDescriptorProto_TYPE_MESSAGE = 11,
-  google_protobuf_FieldDescriptorProto_TYPE_BYTES = 12,
-  google_protobuf_FieldDescriptorProto_TYPE_UINT32 = 13,
-  google_protobuf_FieldDescriptorProto_TYPE_ENUM = 14,
-  google_protobuf_FieldDescriptorProto_TYPE_SFIXED32 = 15,
-  google_protobuf_FieldDescriptorProto_TYPE_SFIXED64 = 16,
-  google_protobuf_FieldDescriptorProto_TYPE_SINT32 = 17,
-  google_protobuf_FieldDescriptorProto_TYPE_SINT64 = 18
-} google_protobuf_FieldDescriptorProto_Type;
-
-typedef enum {
-  google_protobuf_FieldOptions_STRING = 0,
-  google_protobuf_FieldOptions_CORD = 1,
-  google_protobuf_FieldOptions_STRING_PIECE = 2
-} google_protobuf_FieldOptions_CType;
-
-typedef enum {
-  google_protobuf_FieldOptions_JS_NORMAL = 0,
-  google_protobuf_FieldOptions_JS_STRING = 1,
-  google_protobuf_FieldOptions_JS_NUMBER = 2
-} google_protobuf_FieldOptions_JSType;
-
-typedef enum {
-  google_protobuf_FileOptions_SPEED = 1,
-  google_protobuf_FileOptions_CODE_SIZE = 2,
-  google_protobuf_FileOptions_LITE_RUNTIME = 3
-} google_protobuf_FileOptions_OptimizeMode;
-
-typedef enum {
-  google_protobuf_MethodOptions_IDEMPOTENCY_UNKNOWN = 0,
-  google_protobuf_MethodOptions_NO_SIDE_EFFECTS = 1,
-  google_protobuf_MethodOptions_IDEMPOTENT = 2
-} google_protobuf_MethodOptions_IdempotencyLevel;
-
-/* google.protobuf.FileDescriptorSet */
-
-extern const upb_msglayout google_protobuf_FileDescriptorSet_msginit;
-UPB_INLINE google_protobuf_FileDescriptorSet *google_protobuf_FileDescriptorSet_new(upb_arena *arena) {
-  return (google_protobuf_FileDescriptorSet *)upb_msg_new(&google_protobuf_FileDescriptorSet_msginit, arena);
-}
-UPB_INLINE google_protobuf_FileDescriptorSet *google_protobuf_FileDescriptorSet_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_FileDescriptorSet *ret = google_protobuf_FileDescriptorSet_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_FileDescriptorSet_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_FileDescriptorSet_serialize(const google_protobuf_FileDescriptorSet *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_FileDescriptorSet_msginit, arena, len);
-}
-
-UPB_INLINE const upb_array* google_protobuf_FileDescriptorSet_file(const google_protobuf_FileDescriptorSet *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(0, 0)); }
-
-UPB_INLINE void google_protobuf_FileDescriptorSet_set_file(google_protobuf_FileDescriptorSet *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(0, 0)) = value; }
-
-
-/* google.protobuf.FileDescriptorProto */
-
-extern const upb_msglayout google_protobuf_FileDescriptorProto_msginit;
-UPB_INLINE google_protobuf_FileDescriptorProto *google_protobuf_FileDescriptorProto_new(upb_arena *arena) {
-  return (google_protobuf_FileDescriptorProto *)upb_msg_new(&google_protobuf_FileDescriptorProto_msginit, arena);
-}
-UPB_INLINE google_protobuf_FileDescriptorProto *google_protobuf_FileDescriptorProto_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_FileDescriptorProto *ret = google_protobuf_FileDescriptorProto_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_FileDescriptorProto_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_FileDescriptorProto_serialize(const google_protobuf_FileDescriptorProto *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_FileDescriptorProto_msginit, arena, len);
-}
-
-UPB_INLINE upb_stringview google_protobuf_FileDescriptorProto_name(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)); }
-UPB_INLINE upb_stringview google_protobuf_FileDescriptorProto_package(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(16, 32)); }
-UPB_INLINE const upb_array* google_protobuf_FileDescriptorProto_dependency(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(40, 80)); }
-UPB_INLINE const upb_array* google_protobuf_FileDescriptorProto_message_type(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(44, 88)); }
-UPB_INLINE const upb_array* google_protobuf_FileDescriptorProto_enum_type(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(48, 96)); }
-UPB_INLINE const upb_array* google_protobuf_FileDescriptorProto_service(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(52, 104)); }
-UPB_INLINE const upb_array* google_protobuf_FileDescriptorProto_extension(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(56, 112)); }
-UPB_INLINE const google_protobuf_FileOptions* google_protobuf_FileDescriptorProto_options(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_FileOptions*, UPB_SIZE(32, 64)); }
-UPB_INLINE const google_protobuf_SourceCodeInfo* google_protobuf_FileDescriptorProto_source_code_info(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_SourceCodeInfo*, UPB_SIZE(36, 72)); }
-UPB_INLINE const upb_array* google_protobuf_FileDescriptorProto_public_dependency(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(60, 120)); }
-UPB_INLINE const upb_array* google_protobuf_FileDescriptorProto_weak_dependency(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(64, 128)); }
-UPB_INLINE upb_stringview google_protobuf_FileDescriptorProto_syntax(const google_protobuf_FileDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(24, 48)); }
-
-UPB_INLINE void google_protobuf_FileDescriptorProto_set_name(google_protobuf_FileDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)) = value; }
-UPB_INLINE void google_protobuf_FileDescriptorProto_set_package(google_protobuf_FileDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(16, 32)) = value; }
-UPB_INLINE void google_protobuf_FileDescriptorProto_set_dependency(google_protobuf_FileDescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(40, 80)) = value; }
-UPB_INLINE void google_protobuf_FileDescriptorProto_set_message_type(google_protobuf_FileDescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(44, 88)) = value; }
-UPB_INLINE void google_protobuf_FileDescriptorProto_set_enum_type(google_protobuf_FileDescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(48, 96)) = value; }
-UPB_INLINE void google_protobuf_FileDescriptorProto_set_service(google_protobuf_FileDescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(52, 104)) = value; }
-UPB_INLINE void google_protobuf_FileDescriptorProto_set_extension(google_protobuf_FileDescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(56, 112)) = value; }
-UPB_INLINE void google_protobuf_FileDescriptorProto_set_options(google_protobuf_FileDescriptorProto *msg, google_protobuf_FileOptions* value) { UPB_FIELD_AT(msg, google_protobuf_FileOptions*, UPB_SIZE(32, 64)) = value; }
-UPB_INLINE void google_protobuf_FileDescriptorProto_set_source_code_info(google_protobuf_FileDescriptorProto *msg, google_protobuf_SourceCodeInfo* value) { UPB_FIELD_AT(msg, google_protobuf_SourceCodeInfo*, UPB_SIZE(36, 72)) = value; }
-UPB_INLINE void google_protobuf_FileDescriptorProto_set_public_dependency(google_protobuf_FileDescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(60, 120)) = value; }
-UPB_INLINE void google_protobuf_FileDescriptorProto_set_weak_dependency(google_protobuf_FileDescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(64, 128)) = value; }
-UPB_INLINE void google_protobuf_FileDescriptorProto_set_syntax(google_protobuf_FileDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(24, 48)) = value; }
-
-
-/* google.protobuf.DescriptorProto */
-
-extern const upb_msglayout google_protobuf_DescriptorProto_msginit;
-UPB_INLINE google_protobuf_DescriptorProto *google_protobuf_DescriptorProto_new(upb_arena *arena) {
-  return (google_protobuf_DescriptorProto *)upb_msg_new(&google_protobuf_DescriptorProto_msginit, arena);
-}
-UPB_INLINE google_protobuf_DescriptorProto *google_protobuf_DescriptorProto_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_DescriptorProto *ret = google_protobuf_DescriptorProto_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_DescriptorProto_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_DescriptorProto_serialize(const google_protobuf_DescriptorProto *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_DescriptorProto_msginit, arena, len);
-}
-
-UPB_INLINE upb_stringview google_protobuf_DescriptorProto_name(const google_protobuf_DescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)); }
-UPB_INLINE const upb_array* google_protobuf_DescriptorProto_field(const google_protobuf_DescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(20, 40)); }
-UPB_INLINE const upb_array* google_protobuf_DescriptorProto_nested_type(const google_protobuf_DescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(24, 48)); }
-UPB_INLINE const upb_array* google_protobuf_DescriptorProto_enum_type(const google_protobuf_DescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(28, 56)); }
-UPB_INLINE const upb_array* google_protobuf_DescriptorProto_extension_range(const google_protobuf_DescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(32, 64)); }
-UPB_INLINE const upb_array* google_protobuf_DescriptorProto_extension(const google_protobuf_DescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(36, 72)); }
-UPB_INLINE const google_protobuf_MessageOptions* google_protobuf_DescriptorProto_options(const google_protobuf_DescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_MessageOptions*, UPB_SIZE(16, 32)); }
-UPB_INLINE const upb_array* google_protobuf_DescriptorProto_oneof_decl(const google_protobuf_DescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(40, 80)); }
-UPB_INLINE const upb_array* google_protobuf_DescriptorProto_reserved_range(const google_protobuf_DescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(44, 88)); }
-UPB_INLINE const upb_array* google_protobuf_DescriptorProto_reserved_name(const google_protobuf_DescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(48, 96)); }
-
-UPB_INLINE void google_protobuf_DescriptorProto_set_name(google_protobuf_DescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)) = value; }
-UPB_INLINE void google_protobuf_DescriptorProto_set_field(google_protobuf_DescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(20, 40)) = value; }
-UPB_INLINE void google_protobuf_DescriptorProto_set_nested_type(google_protobuf_DescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(24, 48)) = value; }
-UPB_INLINE void google_protobuf_DescriptorProto_set_enum_type(google_protobuf_DescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(28, 56)) = value; }
-UPB_INLINE void google_protobuf_DescriptorProto_set_extension_range(google_protobuf_DescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(32, 64)) = value; }
-UPB_INLINE void google_protobuf_DescriptorProto_set_extension(google_protobuf_DescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(36, 72)) = value; }
-UPB_INLINE void google_protobuf_DescriptorProto_set_options(google_protobuf_DescriptorProto *msg, google_protobuf_MessageOptions* value) { UPB_FIELD_AT(msg, google_protobuf_MessageOptions*, UPB_SIZE(16, 32)) = value; }
-UPB_INLINE void google_protobuf_DescriptorProto_set_oneof_decl(google_protobuf_DescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(40, 80)) = value; }
-UPB_INLINE void google_protobuf_DescriptorProto_set_reserved_range(google_protobuf_DescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(44, 88)) = value; }
-UPB_INLINE void google_protobuf_DescriptorProto_set_reserved_name(google_protobuf_DescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(48, 96)) = value; }
-
-
-/* google.protobuf.DescriptorProto.ExtensionRange */
-
-extern const upb_msglayout google_protobuf_DescriptorProto_ExtensionRange_msginit;
-UPB_INLINE google_protobuf_DescriptorProto_ExtensionRange *google_protobuf_DescriptorProto_ExtensionRange_new(upb_arena *arena) {
-  return (google_protobuf_DescriptorProto_ExtensionRange *)upb_msg_new(&google_protobuf_DescriptorProto_ExtensionRange_msginit, arena);
-}
-UPB_INLINE google_protobuf_DescriptorProto_ExtensionRange *google_protobuf_DescriptorProto_ExtensionRange_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_DescriptorProto_ExtensionRange *ret = google_protobuf_DescriptorProto_ExtensionRange_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_DescriptorProto_ExtensionRange_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_DescriptorProto_ExtensionRange_serialize(const google_protobuf_DescriptorProto_ExtensionRange *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_DescriptorProto_ExtensionRange_msginit, arena, len);
-}
-
-UPB_INLINE int32_t google_protobuf_DescriptorProto_ExtensionRange_start(const google_protobuf_DescriptorProto_ExtensionRange *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)); }
-UPB_INLINE int32_t google_protobuf_DescriptorProto_ExtensionRange_end(const google_protobuf_DescriptorProto_ExtensionRange *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)); }
-UPB_INLINE const google_protobuf_ExtensionRangeOptions* google_protobuf_DescriptorProto_ExtensionRange_options(const google_protobuf_DescriptorProto_ExtensionRange *msg) { return UPB_FIELD_AT(msg, const google_protobuf_ExtensionRangeOptions*, UPB_SIZE(12, 16)); }
-
-UPB_INLINE void google_protobuf_DescriptorProto_ExtensionRange_set_start(google_protobuf_DescriptorProto_ExtensionRange *msg, int32_t value) { UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)) = value; }
-UPB_INLINE void google_protobuf_DescriptorProto_ExtensionRange_set_end(google_protobuf_DescriptorProto_ExtensionRange *msg, int32_t value) { UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)) = value; }
-UPB_INLINE void google_protobuf_DescriptorProto_ExtensionRange_set_options(google_protobuf_DescriptorProto_ExtensionRange *msg, google_protobuf_ExtensionRangeOptions* value) { UPB_FIELD_AT(msg, google_protobuf_ExtensionRangeOptions*, UPB_SIZE(12, 16)) = value; }
-
-
-/* google.protobuf.DescriptorProto.ReservedRange */
-
-extern const upb_msglayout google_protobuf_DescriptorProto_ReservedRange_msginit;
-UPB_INLINE google_protobuf_DescriptorProto_ReservedRange *google_protobuf_DescriptorProto_ReservedRange_new(upb_arena *arena) {
-  return (google_protobuf_DescriptorProto_ReservedRange *)upb_msg_new(&google_protobuf_DescriptorProto_ReservedRange_msginit, arena);
-}
-UPB_INLINE google_protobuf_DescriptorProto_ReservedRange *google_protobuf_DescriptorProto_ReservedRange_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_DescriptorProto_ReservedRange *ret = google_protobuf_DescriptorProto_ReservedRange_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_DescriptorProto_ReservedRange_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_DescriptorProto_ReservedRange_serialize(const google_protobuf_DescriptorProto_ReservedRange *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_DescriptorProto_ReservedRange_msginit, arena, len);
-}
-
-UPB_INLINE int32_t google_protobuf_DescriptorProto_ReservedRange_start(const google_protobuf_DescriptorProto_ReservedRange *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)); }
-UPB_INLINE int32_t google_protobuf_DescriptorProto_ReservedRange_end(const google_protobuf_DescriptorProto_ReservedRange *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)); }
-
-UPB_INLINE void google_protobuf_DescriptorProto_ReservedRange_set_start(google_protobuf_DescriptorProto_ReservedRange *msg, int32_t value) { UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)) = value; }
-UPB_INLINE void google_protobuf_DescriptorProto_ReservedRange_set_end(google_protobuf_DescriptorProto_ReservedRange *msg, int32_t value) { UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)) = value; }
-
-
-/* google.protobuf.ExtensionRangeOptions */
-
-extern const upb_msglayout google_protobuf_ExtensionRangeOptions_msginit;
-UPB_INLINE google_protobuf_ExtensionRangeOptions *google_protobuf_ExtensionRangeOptions_new(upb_arena *arena) {
-  return (google_protobuf_ExtensionRangeOptions *)upb_msg_new(&google_protobuf_ExtensionRangeOptions_msginit, arena);
-}
-UPB_INLINE google_protobuf_ExtensionRangeOptions *google_protobuf_ExtensionRangeOptions_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_ExtensionRangeOptions *ret = google_protobuf_ExtensionRangeOptions_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_ExtensionRangeOptions_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_ExtensionRangeOptions_serialize(const google_protobuf_ExtensionRangeOptions *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_ExtensionRangeOptions_msginit, arena, len);
-}
-
-UPB_INLINE const upb_array* google_protobuf_ExtensionRangeOptions_uninterpreted_option(const google_protobuf_ExtensionRangeOptions *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(0, 0)); }
-
-UPB_INLINE void google_protobuf_ExtensionRangeOptions_set_uninterpreted_option(google_protobuf_ExtensionRangeOptions *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(0, 0)) = value; }
-
-
-/* google.protobuf.FieldDescriptorProto */
-
-extern const upb_msglayout google_protobuf_FieldDescriptorProto_msginit;
-UPB_INLINE google_protobuf_FieldDescriptorProto *google_protobuf_FieldDescriptorProto_new(upb_arena *arena) {
-  return (google_protobuf_FieldDescriptorProto *)upb_msg_new(&google_protobuf_FieldDescriptorProto_msginit, arena);
-}
-UPB_INLINE google_protobuf_FieldDescriptorProto *google_protobuf_FieldDescriptorProto_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_FieldDescriptorProto *ret = google_protobuf_FieldDescriptorProto_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_FieldDescriptorProto_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_FieldDescriptorProto_serialize(const google_protobuf_FieldDescriptorProto *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_FieldDescriptorProto_msginit, arena, len);
-}
-
-UPB_INLINE upb_stringview google_protobuf_FieldDescriptorProto_name(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(32, 32)); }
-UPB_INLINE upb_stringview google_protobuf_FieldDescriptorProto_extendee(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(40, 48)); }
-UPB_INLINE int32_t google_protobuf_FieldDescriptorProto_number(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(24, 24)); }
-UPB_INLINE google_protobuf_FieldDescriptorProto_Label google_protobuf_FieldDescriptorProto_label(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, google_protobuf_FieldDescriptorProto_Label, UPB_SIZE(8, 8)); }
-UPB_INLINE google_protobuf_FieldDescriptorProto_Type google_protobuf_FieldDescriptorProto_type(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, google_protobuf_FieldDescriptorProto_Type, UPB_SIZE(16, 16)); }
-UPB_INLINE upb_stringview google_protobuf_FieldDescriptorProto_type_name(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(48, 64)); }
-UPB_INLINE upb_stringview google_protobuf_FieldDescriptorProto_default_value(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(56, 80)); }
-UPB_INLINE const google_protobuf_FieldOptions* google_protobuf_FieldDescriptorProto_options(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_FieldOptions*, UPB_SIZE(72, 112)); }
-UPB_INLINE int32_t google_protobuf_FieldDescriptorProto_oneof_index(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(28, 28)); }
-UPB_INLINE upb_stringview google_protobuf_FieldDescriptorProto_json_name(const google_protobuf_FieldDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(64, 96)); }
-
-UPB_INLINE void google_protobuf_FieldDescriptorProto_set_name(google_protobuf_FieldDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(32, 32)) = value; }
-UPB_INLINE void google_protobuf_FieldDescriptorProto_set_extendee(google_protobuf_FieldDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(40, 48)) = value; }
-UPB_INLINE void google_protobuf_FieldDescriptorProto_set_number(google_protobuf_FieldDescriptorProto *msg, int32_t value) { UPB_FIELD_AT(msg, int32_t, UPB_SIZE(24, 24)) = value; }
-UPB_INLINE void google_protobuf_FieldDescriptorProto_set_label(google_protobuf_FieldDescriptorProto *msg, google_protobuf_FieldDescriptorProto_Label value) { UPB_FIELD_AT(msg, google_protobuf_FieldDescriptorProto_Label, UPB_SIZE(8, 8)) = value; }
-UPB_INLINE void google_protobuf_FieldDescriptorProto_set_type(google_protobuf_FieldDescriptorProto *msg, google_protobuf_FieldDescriptorProto_Type value) { UPB_FIELD_AT(msg, google_protobuf_FieldDescriptorProto_Type, UPB_SIZE(16, 16)) = value; }
-UPB_INLINE void google_protobuf_FieldDescriptorProto_set_type_name(google_protobuf_FieldDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(48, 64)) = value; }
-UPB_INLINE void google_protobuf_FieldDescriptorProto_set_default_value(google_protobuf_FieldDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(56, 80)) = value; }
-UPB_INLINE void google_protobuf_FieldDescriptorProto_set_options(google_protobuf_FieldDescriptorProto *msg, google_protobuf_FieldOptions* value) { UPB_FIELD_AT(msg, google_protobuf_FieldOptions*, UPB_SIZE(72, 112)) = value; }
-UPB_INLINE void google_protobuf_FieldDescriptorProto_set_oneof_index(google_protobuf_FieldDescriptorProto *msg, int32_t value) { UPB_FIELD_AT(msg, int32_t, UPB_SIZE(28, 28)) = value; }
-UPB_INLINE void google_protobuf_FieldDescriptorProto_set_json_name(google_protobuf_FieldDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(64, 96)) = value; }
-
-
-/* google.protobuf.OneofDescriptorProto */
-
-extern const upb_msglayout google_protobuf_OneofDescriptorProto_msginit;
-UPB_INLINE google_protobuf_OneofDescriptorProto *google_protobuf_OneofDescriptorProto_new(upb_arena *arena) {
-  return (google_protobuf_OneofDescriptorProto *)upb_msg_new(&google_protobuf_OneofDescriptorProto_msginit, arena);
-}
-UPB_INLINE google_protobuf_OneofDescriptorProto *google_protobuf_OneofDescriptorProto_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_OneofDescriptorProto *ret = google_protobuf_OneofDescriptorProto_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_OneofDescriptorProto_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_OneofDescriptorProto_serialize(const google_protobuf_OneofDescriptorProto *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_OneofDescriptorProto_msginit, arena, len);
-}
-
-UPB_INLINE upb_stringview google_protobuf_OneofDescriptorProto_name(const google_protobuf_OneofDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)); }
-UPB_INLINE const google_protobuf_OneofOptions* google_protobuf_OneofDescriptorProto_options(const google_protobuf_OneofDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_OneofOptions*, UPB_SIZE(16, 32)); }
-
-UPB_INLINE void google_protobuf_OneofDescriptorProto_set_name(google_protobuf_OneofDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)) = value; }
-UPB_INLINE void google_protobuf_OneofDescriptorProto_set_options(google_protobuf_OneofDescriptorProto *msg, google_protobuf_OneofOptions* value) { UPB_FIELD_AT(msg, google_protobuf_OneofOptions*, UPB_SIZE(16, 32)) = value; }
-
-
-/* google.protobuf.EnumDescriptorProto */
-
-extern const upb_msglayout google_protobuf_EnumDescriptorProto_msginit;
-UPB_INLINE google_protobuf_EnumDescriptorProto *google_protobuf_EnumDescriptorProto_new(upb_arena *arena) {
-  return (google_protobuf_EnumDescriptorProto *)upb_msg_new(&google_protobuf_EnumDescriptorProto_msginit, arena);
-}
-UPB_INLINE google_protobuf_EnumDescriptorProto *google_protobuf_EnumDescriptorProto_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_EnumDescriptorProto *ret = google_protobuf_EnumDescriptorProto_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_EnumDescriptorProto_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_EnumDescriptorProto_serialize(const google_protobuf_EnumDescriptorProto *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_EnumDescriptorProto_msginit, arena, len);
-}
-
-UPB_INLINE upb_stringview google_protobuf_EnumDescriptorProto_name(const google_protobuf_EnumDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)); }
-UPB_INLINE const upb_array* google_protobuf_EnumDescriptorProto_value(const google_protobuf_EnumDescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(20, 40)); }
-UPB_INLINE const google_protobuf_EnumOptions* google_protobuf_EnumDescriptorProto_options(const google_protobuf_EnumDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_EnumOptions*, UPB_SIZE(16, 32)); }
-UPB_INLINE const upb_array* google_protobuf_EnumDescriptorProto_reserved_range(const google_protobuf_EnumDescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(24, 48)); }
-UPB_INLINE const upb_array* google_protobuf_EnumDescriptorProto_reserved_name(const google_protobuf_EnumDescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(28, 56)); }
-
-UPB_INLINE void google_protobuf_EnumDescriptorProto_set_name(google_protobuf_EnumDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)) = value; }
-UPB_INLINE void google_protobuf_EnumDescriptorProto_set_value(google_protobuf_EnumDescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(20, 40)) = value; }
-UPB_INLINE void google_protobuf_EnumDescriptorProto_set_options(google_protobuf_EnumDescriptorProto *msg, google_protobuf_EnumOptions* value) { UPB_FIELD_AT(msg, google_protobuf_EnumOptions*, UPB_SIZE(16, 32)) = value; }
-UPB_INLINE void google_protobuf_EnumDescriptorProto_set_reserved_range(google_protobuf_EnumDescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(24, 48)) = value; }
-UPB_INLINE void google_protobuf_EnumDescriptorProto_set_reserved_name(google_protobuf_EnumDescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(28, 56)) = value; }
-
-
-/* google.protobuf.EnumDescriptorProto.EnumReservedRange */
-
-extern const upb_msglayout google_protobuf_EnumDescriptorProto_EnumReservedRange_msginit;
-UPB_INLINE google_protobuf_EnumDescriptorProto_EnumReservedRange *google_protobuf_EnumDescriptorProto_EnumReservedRange_new(upb_arena *arena) {
-  return (google_protobuf_EnumDescriptorProto_EnumReservedRange *)upb_msg_new(&google_protobuf_EnumDescriptorProto_EnumReservedRange_msginit, arena);
-}
-UPB_INLINE google_protobuf_EnumDescriptorProto_EnumReservedRange *google_protobuf_EnumDescriptorProto_EnumReservedRange_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_EnumDescriptorProto_EnumReservedRange *ret = google_protobuf_EnumDescriptorProto_EnumReservedRange_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_EnumDescriptorProto_EnumReservedRange_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_EnumDescriptorProto_EnumReservedRange_serialize(const google_protobuf_EnumDescriptorProto_EnumReservedRange *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_EnumDescriptorProto_EnumReservedRange_msginit, arena, len);
-}
-
-UPB_INLINE int32_t google_protobuf_EnumDescriptorProto_EnumReservedRange_start(const google_protobuf_EnumDescriptorProto_EnumReservedRange *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)); }
-UPB_INLINE int32_t google_protobuf_EnumDescriptorProto_EnumReservedRange_end(const google_protobuf_EnumDescriptorProto_EnumReservedRange *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)); }
-
-UPB_INLINE void google_protobuf_EnumDescriptorProto_EnumReservedRange_set_start(google_protobuf_EnumDescriptorProto_EnumReservedRange *msg, int32_t value) { UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)) = value; }
-UPB_INLINE void google_protobuf_EnumDescriptorProto_EnumReservedRange_set_end(google_protobuf_EnumDescriptorProto_EnumReservedRange *msg, int32_t value) { UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)) = value; }
-
-
-/* google.protobuf.EnumValueDescriptorProto */
-
-extern const upb_msglayout google_protobuf_EnumValueDescriptorProto_msginit;
-UPB_INLINE google_protobuf_EnumValueDescriptorProto *google_protobuf_EnumValueDescriptorProto_new(upb_arena *arena) {
-  return (google_protobuf_EnumValueDescriptorProto *)upb_msg_new(&google_protobuf_EnumValueDescriptorProto_msginit, arena);
-}
-UPB_INLINE google_protobuf_EnumValueDescriptorProto *google_protobuf_EnumValueDescriptorProto_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_EnumValueDescriptorProto *ret = google_protobuf_EnumValueDescriptorProto_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_EnumValueDescriptorProto_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_EnumValueDescriptorProto_serialize(const google_protobuf_EnumValueDescriptorProto *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_EnumValueDescriptorProto_msginit, arena, len);
-}
-
-UPB_INLINE upb_stringview google_protobuf_EnumValueDescriptorProto_name(const google_protobuf_EnumValueDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)); }
-UPB_INLINE int32_t google_protobuf_EnumValueDescriptorProto_number(const google_protobuf_EnumValueDescriptorProto *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)); }
-UPB_INLINE const google_protobuf_EnumValueOptions* google_protobuf_EnumValueDescriptorProto_options(const google_protobuf_EnumValueDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_EnumValueOptions*, UPB_SIZE(16, 32)); }
-
-UPB_INLINE void google_protobuf_EnumValueDescriptorProto_set_name(google_protobuf_EnumValueDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)) = value; }
-UPB_INLINE void google_protobuf_EnumValueDescriptorProto_set_number(google_protobuf_EnumValueDescriptorProto *msg, int32_t value) { UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)) = value; }
-UPB_INLINE void google_protobuf_EnumValueDescriptorProto_set_options(google_protobuf_EnumValueDescriptorProto *msg, google_protobuf_EnumValueOptions* value) { UPB_FIELD_AT(msg, google_protobuf_EnumValueOptions*, UPB_SIZE(16, 32)) = value; }
-
-
-/* google.protobuf.ServiceDescriptorProto */
-
-extern const upb_msglayout google_protobuf_ServiceDescriptorProto_msginit;
-UPB_INLINE google_protobuf_ServiceDescriptorProto *google_protobuf_ServiceDescriptorProto_new(upb_arena *arena) {
-  return (google_protobuf_ServiceDescriptorProto *)upb_msg_new(&google_protobuf_ServiceDescriptorProto_msginit, arena);
-}
-UPB_INLINE google_protobuf_ServiceDescriptorProto *google_protobuf_ServiceDescriptorProto_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_ServiceDescriptorProto *ret = google_protobuf_ServiceDescriptorProto_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_ServiceDescriptorProto_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_ServiceDescriptorProto_serialize(const google_protobuf_ServiceDescriptorProto *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_ServiceDescriptorProto_msginit, arena, len);
-}
-
-UPB_INLINE upb_stringview google_protobuf_ServiceDescriptorProto_name(const google_protobuf_ServiceDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)); }
-UPB_INLINE const upb_array* google_protobuf_ServiceDescriptorProto_method(const google_protobuf_ServiceDescriptorProto *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(20, 40)); }
-UPB_INLINE const google_protobuf_ServiceOptions* google_protobuf_ServiceDescriptorProto_options(const google_protobuf_ServiceDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_ServiceOptions*, UPB_SIZE(16, 32)); }
-
-UPB_INLINE void google_protobuf_ServiceDescriptorProto_set_name(google_protobuf_ServiceDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)) = value; }
-UPB_INLINE void google_protobuf_ServiceDescriptorProto_set_method(google_protobuf_ServiceDescriptorProto *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(20, 40)) = value; }
-UPB_INLINE void google_protobuf_ServiceDescriptorProto_set_options(google_protobuf_ServiceDescriptorProto *msg, google_protobuf_ServiceOptions* value) { UPB_FIELD_AT(msg, google_protobuf_ServiceOptions*, UPB_SIZE(16, 32)) = value; }
-
-
-/* google.protobuf.MethodDescriptorProto */
-
-extern const upb_msglayout google_protobuf_MethodDescriptorProto_msginit;
-UPB_INLINE google_protobuf_MethodDescriptorProto *google_protobuf_MethodDescriptorProto_new(upb_arena *arena) {
-  return (google_protobuf_MethodDescriptorProto *)upb_msg_new(&google_protobuf_MethodDescriptorProto_msginit, arena);
-}
-UPB_INLINE google_protobuf_MethodDescriptorProto *google_protobuf_MethodDescriptorProto_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_MethodDescriptorProto *ret = google_protobuf_MethodDescriptorProto_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_MethodDescriptorProto_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_MethodDescriptorProto_serialize(const google_protobuf_MethodDescriptorProto *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_MethodDescriptorProto_msginit, arena, len);
-}
-
-UPB_INLINE upb_stringview google_protobuf_MethodDescriptorProto_name(const google_protobuf_MethodDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)); }
-UPB_INLINE upb_stringview google_protobuf_MethodDescriptorProto_input_type(const google_protobuf_MethodDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(16, 32)); }
-UPB_INLINE upb_stringview google_protobuf_MethodDescriptorProto_output_type(const google_protobuf_MethodDescriptorProto *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(24, 48)); }
-UPB_INLINE const google_protobuf_MethodOptions* google_protobuf_MethodDescriptorProto_options(const google_protobuf_MethodDescriptorProto *msg) { return UPB_FIELD_AT(msg, const google_protobuf_MethodOptions*, UPB_SIZE(32, 64)); }
-UPB_INLINE bool google_protobuf_MethodDescriptorProto_client_streaming(const google_protobuf_MethodDescriptorProto *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)); }
-UPB_INLINE bool google_protobuf_MethodDescriptorProto_server_streaming(const google_protobuf_MethodDescriptorProto *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(2, 2)); }
-
-UPB_INLINE void google_protobuf_MethodDescriptorProto_set_name(google_protobuf_MethodDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)) = value; }
-UPB_INLINE void google_protobuf_MethodDescriptorProto_set_input_type(google_protobuf_MethodDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(16, 32)) = value; }
-UPB_INLINE void google_protobuf_MethodDescriptorProto_set_output_type(google_protobuf_MethodDescriptorProto *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(24, 48)) = value; }
-UPB_INLINE void google_protobuf_MethodDescriptorProto_set_options(google_protobuf_MethodDescriptorProto *msg, google_protobuf_MethodOptions* value) { UPB_FIELD_AT(msg, google_protobuf_MethodOptions*, UPB_SIZE(32, 64)) = value; }
-UPB_INLINE void google_protobuf_MethodDescriptorProto_set_client_streaming(google_protobuf_MethodDescriptorProto *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)) = value; }
-UPB_INLINE void google_protobuf_MethodDescriptorProto_set_server_streaming(google_protobuf_MethodDescriptorProto *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(2, 2)) = value; }
-
-
-/* google.protobuf.FileOptions */
-
-extern const upb_msglayout google_protobuf_FileOptions_msginit;
-UPB_INLINE google_protobuf_FileOptions *google_protobuf_FileOptions_new(upb_arena *arena) {
-  return (google_protobuf_FileOptions *)upb_msg_new(&google_protobuf_FileOptions_msginit, arena);
-}
-UPB_INLINE google_protobuf_FileOptions *google_protobuf_FileOptions_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_FileOptions *ret = google_protobuf_FileOptions_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_FileOptions_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_FileOptions_serialize(const google_protobuf_FileOptions *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_FileOptions_msginit, arena, len);
-}
-
-UPB_INLINE upb_stringview google_protobuf_FileOptions_java_package(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(32, 32)); }
-UPB_INLINE upb_stringview google_protobuf_FileOptions_java_outer_classname(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(40, 48)); }
-UPB_INLINE google_protobuf_FileOptions_OptimizeMode google_protobuf_FileOptions_optimize_for(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, google_protobuf_FileOptions_OptimizeMode, UPB_SIZE(8, 8)); }
-UPB_INLINE bool google_protobuf_FileOptions_java_multiple_files(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(16, 16)); }
-UPB_INLINE upb_stringview google_protobuf_FileOptions_go_package(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(48, 64)); }
-UPB_INLINE bool google_protobuf_FileOptions_cc_generic_services(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(17, 17)); }
-UPB_INLINE bool google_protobuf_FileOptions_java_generic_services(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(18, 18)); }
-UPB_INLINE bool google_protobuf_FileOptions_py_generic_services(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(19, 19)); }
-UPB_INLINE bool google_protobuf_FileOptions_java_generate_equals_and_hash(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(20, 20)); }
-UPB_INLINE bool google_protobuf_FileOptions_deprecated(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(21, 21)); }
-UPB_INLINE bool google_protobuf_FileOptions_java_string_check_utf8(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(22, 22)); }
-UPB_INLINE bool google_protobuf_FileOptions_cc_enable_arenas(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(23, 23)); }
-UPB_INLINE upb_stringview google_protobuf_FileOptions_objc_class_prefix(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(56, 80)); }
-UPB_INLINE upb_stringview google_protobuf_FileOptions_csharp_namespace(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(64, 96)); }
-UPB_INLINE upb_stringview google_protobuf_FileOptions_swift_prefix(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(72, 112)); }
-UPB_INLINE upb_stringview google_protobuf_FileOptions_php_class_prefix(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(80, 128)); }
-UPB_INLINE upb_stringview google_protobuf_FileOptions_php_namespace(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(88, 144)); }
-UPB_INLINE bool google_protobuf_FileOptions_php_generic_services(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(24, 24)); }
-UPB_INLINE const upb_array* google_protobuf_FileOptions_uninterpreted_option(const google_protobuf_FileOptions *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(96, 160)); }
-
-UPB_INLINE void google_protobuf_FileOptions_set_java_package(google_protobuf_FileOptions *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(32, 32)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_java_outer_classname(google_protobuf_FileOptions *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(40, 48)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_optimize_for(google_protobuf_FileOptions *msg, google_protobuf_FileOptions_OptimizeMode value) { UPB_FIELD_AT(msg, google_protobuf_FileOptions_OptimizeMode, UPB_SIZE(8, 8)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_java_multiple_files(google_protobuf_FileOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(16, 16)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_go_package(google_protobuf_FileOptions *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(48, 64)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_cc_generic_services(google_protobuf_FileOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(17, 17)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_java_generic_services(google_protobuf_FileOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(18, 18)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_py_generic_services(google_protobuf_FileOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(19, 19)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_java_generate_equals_and_hash(google_protobuf_FileOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(20, 20)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_deprecated(google_protobuf_FileOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(21, 21)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_java_string_check_utf8(google_protobuf_FileOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(22, 22)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_cc_enable_arenas(google_protobuf_FileOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(23, 23)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_objc_class_prefix(google_protobuf_FileOptions *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(56, 80)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_csharp_namespace(google_protobuf_FileOptions *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(64, 96)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_swift_prefix(google_protobuf_FileOptions *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(72, 112)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_php_class_prefix(google_protobuf_FileOptions *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(80, 128)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_php_namespace(google_protobuf_FileOptions *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(88, 144)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_php_generic_services(google_protobuf_FileOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(24, 24)) = value; }
-UPB_INLINE void google_protobuf_FileOptions_set_uninterpreted_option(google_protobuf_FileOptions *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(96, 160)) = value; }
-
-
-/* google.protobuf.MessageOptions */
-
-extern const upb_msglayout google_protobuf_MessageOptions_msginit;
-UPB_INLINE google_protobuf_MessageOptions *google_protobuf_MessageOptions_new(upb_arena *arena) {
-  return (google_protobuf_MessageOptions *)upb_msg_new(&google_protobuf_MessageOptions_msginit, arena);
-}
-UPB_INLINE google_protobuf_MessageOptions *google_protobuf_MessageOptions_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_MessageOptions *ret = google_protobuf_MessageOptions_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_MessageOptions_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_MessageOptions_serialize(const google_protobuf_MessageOptions *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_MessageOptions_msginit, arena, len);
-}
-
-UPB_INLINE bool google_protobuf_MessageOptions_message_set_wire_format(const google_protobuf_MessageOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)); }
-UPB_INLINE bool google_protobuf_MessageOptions_no_standard_descriptor_accessor(const google_protobuf_MessageOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(2, 2)); }
-UPB_INLINE bool google_protobuf_MessageOptions_deprecated(const google_protobuf_MessageOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(3, 3)); }
-UPB_INLINE bool google_protobuf_MessageOptions_map_entry(const google_protobuf_MessageOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(4, 4)); }
-UPB_INLINE const upb_array* google_protobuf_MessageOptions_uninterpreted_option(const google_protobuf_MessageOptions *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(8, 8)); }
-
-UPB_INLINE void google_protobuf_MessageOptions_set_message_set_wire_format(google_protobuf_MessageOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)) = value; }
-UPB_INLINE void google_protobuf_MessageOptions_set_no_standard_descriptor_accessor(google_protobuf_MessageOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(2, 2)) = value; }
-UPB_INLINE void google_protobuf_MessageOptions_set_deprecated(google_protobuf_MessageOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(3, 3)) = value; }
-UPB_INLINE void google_protobuf_MessageOptions_set_map_entry(google_protobuf_MessageOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(4, 4)) = value; }
-UPB_INLINE void google_protobuf_MessageOptions_set_uninterpreted_option(google_protobuf_MessageOptions *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(8, 8)) = value; }
-
-
-/* google.protobuf.FieldOptions */
-
-extern const upb_msglayout google_protobuf_FieldOptions_msginit;
-UPB_INLINE google_protobuf_FieldOptions *google_protobuf_FieldOptions_new(upb_arena *arena) {
-  return (google_protobuf_FieldOptions *)upb_msg_new(&google_protobuf_FieldOptions_msginit, arena);
-}
-UPB_INLINE google_protobuf_FieldOptions *google_protobuf_FieldOptions_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_FieldOptions *ret = google_protobuf_FieldOptions_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_FieldOptions_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_FieldOptions_serialize(const google_protobuf_FieldOptions *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_FieldOptions_msginit, arena, len);
-}
-
-UPB_INLINE google_protobuf_FieldOptions_CType google_protobuf_FieldOptions_ctype(const google_protobuf_FieldOptions *msg) { return UPB_FIELD_AT(msg, google_protobuf_FieldOptions_CType, UPB_SIZE(8, 8)); }
-UPB_INLINE bool google_protobuf_FieldOptions_packed(const google_protobuf_FieldOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(24, 24)); }
-UPB_INLINE bool google_protobuf_FieldOptions_deprecated(const google_protobuf_FieldOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(25, 25)); }
-UPB_INLINE bool google_protobuf_FieldOptions_lazy(const google_protobuf_FieldOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(26, 26)); }
-UPB_INLINE google_protobuf_FieldOptions_JSType google_protobuf_FieldOptions_jstype(const google_protobuf_FieldOptions *msg) { return UPB_FIELD_AT(msg, google_protobuf_FieldOptions_JSType, UPB_SIZE(16, 16)); }
-UPB_INLINE bool google_protobuf_FieldOptions_weak(const google_protobuf_FieldOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(27, 27)); }
-UPB_INLINE const upb_array* google_protobuf_FieldOptions_uninterpreted_option(const google_protobuf_FieldOptions *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(28, 32)); }
-
-UPB_INLINE void google_protobuf_FieldOptions_set_ctype(google_protobuf_FieldOptions *msg, google_protobuf_FieldOptions_CType value) { UPB_FIELD_AT(msg, google_protobuf_FieldOptions_CType, UPB_SIZE(8, 8)) = value; }
-UPB_INLINE void google_protobuf_FieldOptions_set_packed(google_protobuf_FieldOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(24, 24)) = value; }
-UPB_INLINE void google_protobuf_FieldOptions_set_deprecated(google_protobuf_FieldOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(25, 25)) = value; }
-UPB_INLINE void google_protobuf_FieldOptions_set_lazy(google_protobuf_FieldOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(26, 26)) = value; }
-UPB_INLINE void google_protobuf_FieldOptions_set_jstype(google_protobuf_FieldOptions *msg, google_protobuf_FieldOptions_JSType value) { UPB_FIELD_AT(msg, google_protobuf_FieldOptions_JSType, UPB_SIZE(16, 16)) = value; }
-UPB_INLINE void google_protobuf_FieldOptions_set_weak(google_protobuf_FieldOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(27, 27)) = value; }
-UPB_INLINE void google_protobuf_FieldOptions_set_uninterpreted_option(google_protobuf_FieldOptions *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(28, 32)) = value; }
-
-
-/* google.protobuf.OneofOptions */
-
-extern const upb_msglayout google_protobuf_OneofOptions_msginit;
-UPB_INLINE google_protobuf_OneofOptions *google_protobuf_OneofOptions_new(upb_arena *arena) {
-  return (google_protobuf_OneofOptions *)upb_msg_new(&google_protobuf_OneofOptions_msginit, arena);
-}
-UPB_INLINE google_protobuf_OneofOptions *google_protobuf_OneofOptions_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_OneofOptions *ret = google_protobuf_OneofOptions_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_OneofOptions_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_OneofOptions_serialize(const google_protobuf_OneofOptions *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_OneofOptions_msginit, arena, len);
-}
-
-UPB_INLINE const upb_array* google_protobuf_OneofOptions_uninterpreted_option(const google_protobuf_OneofOptions *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(0, 0)); }
-
-UPB_INLINE void google_protobuf_OneofOptions_set_uninterpreted_option(google_protobuf_OneofOptions *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(0, 0)) = value; }
-
-
-/* google.protobuf.EnumOptions */
-
-extern const upb_msglayout google_protobuf_EnumOptions_msginit;
-UPB_INLINE google_protobuf_EnumOptions *google_protobuf_EnumOptions_new(upb_arena *arena) {
-  return (google_protobuf_EnumOptions *)upb_msg_new(&google_protobuf_EnumOptions_msginit, arena);
-}
-UPB_INLINE google_protobuf_EnumOptions *google_protobuf_EnumOptions_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_EnumOptions *ret = google_protobuf_EnumOptions_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_EnumOptions_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_EnumOptions_serialize(const google_protobuf_EnumOptions *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_EnumOptions_msginit, arena, len);
-}
-
-UPB_INLINE bool google_protobuf_EnumOptions_allow_alias(const google_protobuf_EnumOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)); }
-UPB_INLINE bool google_protobuf_EnumOptions_deprecated(const google_protobuf_EnumOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(2, 2)); }
-UPB_INLINE const upb_array* google_protobuf_EnumOptions_uninterpreted_option(const google_protobuf_EnumOptions *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(4, 8)); }
-
-UPB_INLINE void google_protobuf_EnumOptions_set_allow_alias(google_protobuf_EnumOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)) = value; }
-UPB_INLINE void google_protobuf_EnumOptions_set_deprecated(google_protobuf_EnumOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(2, 2)) = value; }
-UPB_INLINE void google_protobuf_EnumOptions_set_uninterpreted_option(google_protobuf_EnumOptions *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(4, 8)) = value; }
-
-
-/* google.protobuf.EnumValueOptions */
-
-extern const upb_msglayout google_protobuf_EnumValueOptions_msginit;
-UPB_INLINE google_protobuf_EnumValueOptions *google_protobuf_EnumValueOptions_new(upb_arena *arena) {
-  return (google_protobuf_EnumValueOptions *)upb_msg_new(&google_protobuf_EnumValueOptions_msginit, arena);
-}
-UPB_INLINE google_protobuf_EnumValueOptions *google_protobuf_EnumValueOptions_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_EnumValueOptions *ret = google_protobuf_EnumValueOptions_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_EnumValueOptions_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_EnumValueOptions_serialize(const google_protobuf_EnumValueOptions *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_EnumValueOptions_msginit, arena, len);
-}
-
-UPB_INLINE bool google_protobuf_EnumValueOptions_deprecated(const google_protobuf_EnumValueOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)); }
-UPB_INLINE const upb_array* google_protobuf_EnumValueOptions_uninterpreted_option(const google_protobuf_EnumValueOptions *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(4, 8)); }
-
-UPB_INLINE void google_protobuf_EnumValueOptions_set_deprecated(google_protobuf_EnumValueOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)) = value; }
-UPB_INLINE void google_protobuf_EnumValueOptions_set_uninterpreted_option(google_protobuf_EnumValueOptions *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(4, 8)) = value; }
-
-
-/* google.protobuf.ServiceOptions */
-
-extern const upb_msglayout google_protobuf_ServiceOptions_msginit;
-UPB_INLINE google_protobuf_ServiceOptions *google_protobuf_ServiceOptions_new(upb_arena *arena) {
-  return (google_protobuf_ServiceOptions *)upb_msg_new(&google_protobuf_ServiceOptions_msginit, arena);
-}
-UPB_INLINE google_protobuf_ServiceOptions *google_protobuf_ServiceOptions_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_ServiceOptions *ret = google_protobuf_ServiceOptions_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_ServiceOptions_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_ServiceOptions_serialize(const google_protobuf_ServiceOptions *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_ServiceOptions_msginit, arena, len);
-}
-
-UPB_INLINE bool google_protobuf_ServiceOptions_deprecated(const google_protobuf_ServiceOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)); }
-UPB_INLINE const upb_array* google_protobuf_ServiceOptions_uninterpreted_option(const google_protobuf_ServiceOptions *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(4, 8)); }
-
-UPB_INLINE void google_protobuf_ServiceOptions_set_deprecated(google_protobuf_ServiceOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)) = value; }
-UPB_INLINE void google_protobuf_ServiceOptions_set_uninterpreted_option(google_protobuf_ServiceOptions *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(4, 8)) = value; }
-
-
-/* google.protobuf.MethodOptions */
-
-extern const upb_msglayout google_protobuf_MethodOptions_msginit;
-UPB_INLINE google_protobuf_MethodOptions *google_protobuf_MethodOptions_new(upb_arena *arena) {
-  return (google_protobuf_MethodOptions *)upb_msg_new(&google_protobuf_MethodOptions_msginit, arena);
-}
-UPB_INLINE google_protobuf_MethodOptions *google_protobuf_MethodOptions_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_MethodOptions *ret = google_protobuf_MethodOptions_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_MethodOptions_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_MethodOptions_serialize(const google_protobuf_MethodOptions *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_MethodOptions_msginit, arena, len);
-}
-
-UPB_INLINE bool google_protobuf_MethodOptions_deprecated(const google_protobuf_MethodOptions *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(16, 16)); }
-UPB_INLINE google_protobuf_MethodOptions_IdempotencyLevel google_protobuf_MethodOptions_idempotency_level(const google_protobuf_MethodOptions *msg) { return UPB_FIELD_AT(msg, google_protobuf_MethodOptions_IdempotencyLevel, UPB_SIZE(8, 8)); }
-UPB_INLINE const upb_array* google_protobuf_MethodOptions_uninterpreted_option(const google_protobuf_MethodOptions *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(20, 24)); }
-
-UPB_INLINE void google_protobuf_MethodOptions_set_deprecated(google_protobuf_MethodOptions *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(16, 16)) = value; }
-UPB_INLINE void google_protobuf_MethodOptions_set_idempotency_level(google_protobuf_MethodOptions *msg, google_protobuf_MethodOptions_IdempotencyLevel value) { UPB_FIELD_AT(msg, google_protobuf_MethodOptions_IdempotencyLevel, UPB_SIZE(8, 8)) = value; }
-UPB_INLINE void google_protobuf_MethodOptions_set_uninterpreted_option(google_protobuf_MethodOptions *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(20, 24)) = value; }
-
-
-/* google.protobuf.UninterpretedOption */
-
-extern const upb_msglayout google_protobuf_UninterpretedOption_msginit;
-UPB_INLINE google_protobuf_UninterpretedOption *google_protobuf_UninterpretedOption_new(upb_arena *arena) {
-  return (google_protobuf_UninterpretedOption *)upb_msg_new(&google_protobuf_UninterpretedOption_msginit, arena);
-}
-UPB_INLINE google_protobuf_UninterpretedOption *google_protobuf_UninterpretedOption_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_UninterpretedOption *ret = google_protobuf_UninterpretedOption_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_UninterpretedOption_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_UninterpretedOption_serialize(const google_protobuf_UninterpretedOption *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_UninterpretedOption_msginit, arena, len);
-}
-
-UPB_INLINE const upb_array* google_protobuf_UninterpretedOption_name(const google_protobuf_UninterpretedOption *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(56, 80)); }
-UPB_INLINE upb_stringview google_protobuf_UninterpretedOption_identifier_value(const google_protobuf_UninterpretedOption *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(32, 32)); }
-UPB_INLINE uint64_t google_protobuf_UninterpretedOption_positive_int_value(const google_protobuf_UninterpretedOption *msg) { return UPB_FIELD_AT(msg, uint64_t, UPB_SIZE(8, 8)); }
-UPB_INLINE int64_t google_protobuf_UninterpretedOption_negative_int_value(const google_protobuf_UninterpretedOption *msg) { return UPB_FIELD_AT(msg, int64_t, UPB_SIZE(16, 16)); }
-UPB_INLINE double google_protobuf_UninterpretedOption_double_value(const google_protobuf_UninterpretedOption *msg) { return UPB_FIELD_AT(msg, double, UPB_SIZE(24, 24)); }
-UPB_INLINE upb_stringview google_protobuf_UninterpretedOption_string_value(const google_protobuf_UninterpretedOption *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(40, 48)); }
-UPB_INLINE upb_stringview google_protobuf_UninterpretedOption_aggregate_value(const google_protobuf_UninterpretedOption *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(48, 64)); }
-
-UPB_INLINE void google_protobuf_UninterpretedOption_set_name(google_protobuf_UninterpretedOption *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(56, 80)) = value; }
-UPB_INLINE void google_protobuf_UninterpretedOption_set_identifier_value(google_protobuf_UninterpretedOption *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(32, 32)) = value; }
-UPB_INLINE void google_protobuf_UninterpretedOption_set_positive_int_value(google_protobuf_UninterpretedOption *msg, uint64_t value) { UPB_FIELD_AT(msg, uint64_t, UPB_SIZE(8, 8)) = value; }
-UPB_INLINE void google_protobuf_UninterpretedOption_set_negative_int_value(google_protobuf_UninterpretedOption *msg, int64_t value) { UPB_FIELD_AT(msg, int64_t, UPB_SIZE(16, 16)) = value; }
-UPB_INLINE void google_protobuf_UninterpretedOption_set_double_value(google_protobuf_UninterpretedOption *msg, double value) { UPB_FIELD_AT(msg, double, UPB_SIZE(24, 24)) = value; }
-UPB_INLINE void google_protobuf_UninterpretedOption_set_string_value(google_protobuf_UninterpretedOption *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(40, 48)) = value; }
-UPB_INLINE void google_protobuf_UninterpretedOption_set_aggregate_value(google_protobuf_UninterpretedOption *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(48, 64)) = value; }
-
-
-/* google.protobuf.UninterpretedOption.NamePart */
-
-extern const upb_msglayout google_protobuf_UninterpretedOption_NamePart_msginit;
-UPB_INLINE google_protobuf_UninterpretedOption_NamePart *google_protobuf_UninterpretedOption_NamePart_new(upb_arena *arena) {
-  return (google_protobuf_UninterpretedOption_NamePart *)upb_msg_new(&google_protobuf_UninterpretedOption_NamePart_msginit, arena);
-}
-UPB_INLINE google_protobuf_UninterpretedOption_NamePart *google_protobuf_UninterpretedOption_NamePart_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_UninterpretedOption_NamePart *ret = google_protobuf_UninterpretedOption_NamePart_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_UninterpretedOption_NamePart_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_UninterpretedOption_NamePart_serialize(const google_protobuf_UninterpretedOption_NamePart *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_UninterpretedOption_NamePart_msginit, arena, len);
-}
-
-UPB_INLINE upb_stringview google_protobuf_UninterpretedOption_NamePart_name_part(const google_protobuf_UninterpretedOption_NamePart *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)); }
-UPB_INLINE bool google_protobuf_UninterpretedOption_NamePart_is_extension(const google_protobuf_UninterpretedOption_NamePart *msg) { return UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)); }
-
-UPB_INLINE void google_protobuf_UninterpretedOption_NamePart_set_name_part(google_protobuf_UninterpretedOption_NamePart *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)) = value; }
-UPB_INLINE void google_protobuf_UninterpretedOption_NamePart_set_is_extension(google_protobuf_UninterpretedOption_NamePart *msg, bool value) { UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)) = value; }
-
-
-/* google.protobuf.SourceCodeInfo */
-
-extern const upb_msglayout google_protobuf_SourceCodeInfo_msginit;
-UPB_INLINE google_protobuf_SourceCodeInfo *google_protobuf_SourceCodeInfo_new(upb_arena *arena) {
-  return (google_protobuf_SourceCodeInfo *)upb_msg_new(&google_protobuf_SourceCodeInfo_msginit, arena);
-}
-UPB_INLINE google_protobuf_SourceCodeInfo *google_protobuf_SourceCodeInfo_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_SourceCodeInfo *ret = google_protobuf_SourceCodeInfo_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_SourceCodeInfo_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_SourceCodeInfo_serialize(const google_protobuf_SourceCodeInfo *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_SourceCodeInfo_msginit, arena, len);
-}
-
-UPB_INLINE const upb_array* google_protobuf_SourceCodeInfo_location(const google_protobuf_SourceCodeInfo *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(0, 0)); }
-
-UPB_INLINE void google_protobuf_SourceCodeInfo_set_location(google_protobuf_SourceCodeInfo *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(0, 0)) = value; }
-
-
-/* google.protobuf.SourceCodeInfo.Location */
-
-extern const upb_msglayout google_protobuf_SourceCodeInfo_Location_msginit;
-UPB_INLINE google_protobuf_SourceCodeInfo_Location *google_protobuf_SourceCodeInfo_Location_new(upb_arena *arena) {
-  return (google_protobuf_SourceCodeInfo_Location *)upb_msg_new(&google_protobuf_SourceCodeInfo_Location_msginit, arena);
-}
-UPB_INLINE google_protobuf_SourceCodeInfo_Location *google_protobuf_SourceCodeInfo_Location_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_SourceCodeInfo_Location *ret = google_protobuf_SourceCodeInfo_Location_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_SourceCodeInfo_Location_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_SourceCodeInfo_Location_serialize(const google_protobuf_SourceCodeInfo_Location *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_SourceCodeInfo_Location_msginit, arena, len);
-}
-
-UPB_INLINE const upb_array* google_protobuf_SourceCodeInfo_Location_path(const google_protobuf_SourceCodeInfo_Location *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(24, 48)); }
-UPB_INLINE const upb_array* google_protobuf_SourceCodeInfo_Location_span(const google_protobuf_SourceCodeInfo_Location *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(28, 56)); }
-UPB_INLINE upb_stringview google_protobuf_SourceCodeInfo_Location_leading_comments(const google_protobuf_SourceCodeInfo_Location *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)); }
-UPB_INLINE upb_stringview google_protobuf_SourceCodeInfo_Location_trailing_comments(const google_protobuf_SourceCodeInfo_Location *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(16, 32)); }
-UPB_INLINE const upb_array* google_protobuf_SourceCodeInfo_Location_leading_detached_comments(const google_protobuf_SourceCodeInfo_Location *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(32, 64)); }
-
-UPB_INLINE void google_protobuf_SourceCodeInfo_Location_set_path(google_protobuf_SourceCodeInfo_Location *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(24, 48)) = value; }
-UPB_INLINE void google_protobuf_SourceCodeInfo_Location_set_span(google_protobuf_SourceCodeInfo_Location *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(28, 56)) = value; }
-UPB_INLINE void google_protobuf_SourceCodeInfo_Location_set_leading_comments(google_protobuf_SourceCodeInfo_Location *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(8, 16)) = value; }
-UPB_INLINE void google_protobuf_SourceCodeInfo_Location_set_trailing_comments(google_protobuf_SourceCodeInfo_Location *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(16, 32)) = value; }
-UPB_INLINE void google_protobuf_SourceCodeInfo_Location_set_leading_detached_comments(google_protobuf_SourceCodeInfo_Location *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(32, 64)) = value; }
-
-
-/* google.protobuf.GeneratedCodeInfo */
-
-extern const upb_msglayout google_protobuf_GeneratedCodeInfo_msginit;
-UPB_INLINE google_protobuf_GeneratedCodeInfo *google_protobuf_GeneratedCodeInfo_new(upb_arena *arena) {
-  return (google_protobuf_GeneratedCodeInfo *)upb_msg_new(&google_protobuf_GeneratedCodeInfo_msginit, arena);
-}
-UPB_INLINE google_protobuf_GeneratedCodeInfo *google_protobuf_GeneratedCodeInfo_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_GeneratedCodeInfo *ret = google_protobuf_GeneratedCodeInfo_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_GeneratedCodeInfo_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_GeneratedCodeInfo_serialize(const google_protobuf_GeneratedCodeInfo *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_GeneratedCodeInfo_msginit, arena, len);
-}
-
-UPB_INLINE const upb_array* google_protobuf_GeneratedCodeInfo_annotation(const google_protobuf_GeneratedCodeInfo *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(0, 0)); }
-
-UPB_INLINE void google_protobuf_GeneratedCodeInfo_set_annotation(google_protobuf_GeneratedCodeInfo *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(0, 0)) = value; }
-
-
-/* google.protobuf.GeneratedCodeInfo.Annotation */
-
-extern const upb_msglayout google_protobuf_GeneratedCodeInfo_Annotation_msginit;
-UPB_INLINE google_protobuf_GeneratedCodeInfo_Annotation *google_protobuf_GeneratedCodeInfo_Annotation_new(upb_arena *arena) {
-  return (google_protobuf_GeneratedCodeInfo_Annotation *)upb_msg_new(&google_protobuf_GeneratedCodeInfo_Annotation_msginit, arena);
-}
-UPB_INLINE google_protobuf_GeneratedCodeInfo_Annotation *google_protobuf_GeneratedCodeInfo_Annotation_parsenew(upb_stringview buf, upb_arena *arena) {
-  google_protobuf_GeneratedCodeInfo_Annotation *ret = google_protobuf_GeneratedCodeInfo_Annotation_new(arena);
-  return (ret && upb_decode(buf, ret, &google_protobuf_GeneratedCodeInfo_Annotation_msginit)) ? ret : NULL;
-}
-UPB_INLINE char *google_protobuf_GeneratedCodeInfo_Annotation_serialize(const google_protobuf_GeneratedCodeInfo_Annotation *msg, upb_arena *arena, size_t *len) {
-  return upb_encode(msg, &google_protobuf_GeneratedCodeInfo_Annotation_msginit, arena, len);
-}
-
-UPB_INLINE const upb_array* google_protobuf_GeneratedCodeInfo_Annotation_path(const google_protobuf_GeneratedCodeInfo_Annotation *msg) { return UPB_FIELD_AT(msg, const upb_array*, UPB_SIZE(24, 32)); }
-UPB_INLINE upb_stringview google_protobuf_GeneratedCodeInfo_Annotation_source_file(const google_protobuf_GeneratedCodeInfo_Annotation *msg) { return UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(16, 16)); }
-UPB_INLINE int32_t google_protobuf_GeneratedCodeInfo_Annotation_begin(const google_protobuf_GeneratedCodeInfo_Annotation *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)); }
-UPB_INLINE int32_t google_protobuf_GeneratedCodeInfo_Annotation_end(const google_protobuf_GeneratedCodeInfo_Annotation *msg) { return UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)); }
-
-UPB_INLINE void google_protobuf_GeneratedCodeInfo_Annotation_set_path(google_protobuf_GeneratedCodeInfo_Annotation *msg, upb_array* value) { UPB_FIELD_AT(msg, upb_array*, UPB_SIZE(24, 32)) = value; }
-UPB_INLINE void google_protobuf_GeneratedCodeInfo_Annotation_set_source_file(google_protobuf_GeneratedCodeInfo_Annotation *msg, upb_stringview value) { UPB_FIELD_AT(msg, upb_stringview, UPB_SIZE(16, 16)) = value; }
-UPB_INLINE void google_protobuf_GeneratedCodeInfo_Annotation_set_begin(google_protobuf_GeneratedCodeInfo_Annotation *msg, int32_t value) { UPB_FIELD_AT(msg, int32_t, UPB_SIZE(4, 4)) = value; }
-UPB_INLINE void google_protobuf_GeneratedCodeInfo_Annotation_set_end(google_protobuf_GeneratedCodeInfo_Annotation *msg, int32_t value) { UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)) = value; }
-
-
-UPB_END_EXTERN_C
-
-
-#endif  /* GOOGLE_PROTOBUF_DESCRIPTOR_PROTO_UPB_H_ */
-/*
-** structs.int.h: structures definitions that are internal to upb.
-*/
-
-#ifndef UPB_STRUCTS_H_
-#define UPB_STRUCTS_H_
-
-struct upb_array {
-  upb_fieldtype_t type;
-  uint8_t element_size;
-  void *data;   /* Each element is element_size. */
-  size_t len;   /* Measured in elements. */
-  size_t size;  /* Measured in elements. */
-  upb_arena *arena;
-};
-
-#endif  /* UPB_STRUCTS_H_ */
-
-/*
-** This file contains definitions of structs that should be considered private
-** and NOT stable across versions of upb.
-**
-** The only reason they are declared here and not in .c files is to allow upb
-** and the application (if desired) to embed statically-initialized instances
-** of structures like defs.
-**
-** If you include this file, all guarantees of ABI compatibility go out the
-** window!  Any code that includes this file needs to recompile against the
-** exact same version of upb that they are linking against.
-**
-** You also need to recompile if you change the value of the UPB_DEBUG_REFS
-** flag.
-*/
-
-
-#ifndef UPB_STATICINIT_H_
-#define UPB_STATICINIT_H_
-
-#ifdef __cplusplus
-/* Because of how we do our typedefs, this header can't be included from C++. */
-#error This file cannot be included from C++
-#endif
-
-/* upb_refcounted *************************************************************/
-
-
-/* upb_def ********************************************************************/
-
-struct upb_def {
-  upb_refcounted base;
-
-  const char *fullname;
-  const upb_filedef* file;
-  char type;  /* A upb_deftype_t (char to save space) */
-
-  /* Used as a flag during the def's mutable stage.  Must be false unless
-   * it is currently being used by a function on the stack.  This allows
-   * us to easily determine which defs were passed into the function's
-   * current invocation. */
-  bool came_from_user;
-};
-
-#define UPB_DEF_INIT(name, type, vtbl, refs, ref2s) \
-    { UPB_REFCOUNT_INIT(vtbl, refs, ref2s), name, NULL, type, false }
-
-
-/* upb_fielddef ***************************************************************/
-
-struct upb_fielddef {
-  upb_def base;
-
-  union {
-    int64_t sint;
-    uint64_t uint;
-    double dbl;
-    float flt;
-    void *bytes;
-  } defaultval;
-  union {
-    const upb_msgdef *def;  /* If !msg_is_symbolic. */
-    char *name;             /* If msg_is_symbolic. */
-  } msg;
-  union {
-    const upb_def *def;  /* If !subdef_is_symbolic. */
-    char *name;          /* If subdef_is_symbolic. */
-  } sub;  /* The msgdef or enumdef for this field, if upb_hassubdef(f). */
-  bool subdef_is_symbolic;
-  bool msg_is_symbolic;
-  const upb_oneofdef *oneof;
-  bool default_is_string;
-  bool type_is_set_;     /* False until type is explicitly set. */
-  bool is_extension_;
-  bool lazy_;
-  bool packed_;
-  upb_intfmt_t intfmt;
-  bool tagdelim;
-  upb_fieldtype_t type_;
-  upb_label_t label_;
-  uint32_t number_;
-  uint32_t selector_base;  /* Used to index into a upb::Handlers table. */
-  uint32_t index_;
-};
-
-extern const struct upb_refcounted_vtbl upb_fielddef_vtbl;
-
-#define UPB_FIELDDEF_INIT(label, type, intfmt, tagdelim, is_extension, lazy,   \
-                          packed, name, num, msgdef, subdef, selector_base,    \
-                          index, defaultval, refs, ref2s)                      \
-  {                                                                            \
-    UPB_DEF_INIT(name, UPB_DEF_FIELD, &upb_fielddef_vtbl, refs, ref2s),        \
-        defaultval, {msgdef}, {subdef}, NULL, false, false,                    \
-        type == UPB_TYPE_STRING || type == UPB_TYPE_BYTES, true, is_extension, \
-        lazy, packed, intfmt, tagdelim, type, label, num, selector_base, index \
-  }
-
-
-/* upb_msgdef *****************************************************************/
-
-struct upb_msgdef {
-  upb_def base;
-
-  size_t selector_count;
-  uint32_t submsg_field_count;
-
-  /* Tables for looking up fields by number and name. */
-  upb_inttable itof;  /* int to field */
-  upb_strtable ntof;  /* name to field/oneof */
-
-  /* Is this a map-entry message? */
-  bool map_entry;
-
-  /* Whether this message has proto2 or proto3 semantics. */
-  upb_syntax_t syntax;
-
-  /* Type of well known type message. UPB_WELLKNOWN_UNSPECIFIED for
-   * non-well-known message. */
-  upb_wellknowntype_t well_known_type;
-
-  /* TODO(haberman): proper extension ranges (there can be multiple). */
-};
-
-extern const struct upb_refcounted_vtbl upb_msgdef_vtbl;
-
-/* TODO: also support static initialization of the oneofs table. This will be
- * needed if we compile in descriptors that contain oneofs. */
-#define UPB_MSGDEF_INIT(name, selector_count, submsg_field_count, itof, ntof, \
-                        map_entry, syntax, well_known_type, refs, ref2s)      \
-  {                                                                           \
-    UPB_DEF_INIT(name, UPB_DEF_MSG, &upb_fielddef_vtbl, refs, ref2s),         \
-        selector_count, submsg_field_count, itof, ntof, map_entry, syntax,    \
-        well_known_type                                                       \
-  }
-
-
-/* upb_enumdef ****************************************************************/
-
-struct upb_enumdef {
-  upb_def base;
-
-  upb_strtable ntoi;
-  upb_inttable iton;
-  int32_t defaultval;
-};
-
-extern const struct upb_refcounted_vtbl upb_enumdef_vtbl;
-
-#define UPB_ENUMDEF_INIT(name, ntoi, iton, defaultval, refs, ref2s) \
-  { UPB_DEF_INIT(name, UPB_DEF_ENUM, &upb_enumdef_vtbl, refs, ref2s), ntoi,    \
-    iton, defaultval }
-
-
-/* upb_oneofdef ***************************************************************/
-
-struct upb_oneofdef {
-  upb_refcounted base;
-
-  uint32_t index;  /* Index within oneofs. */
-  const char *name;
-  upb_strtable ntof;
-  upb_inttable itof;
-  const upb_msgdef *parent;
-};
-
-extern const struct upb_refcounted_vtbl upb_oneofdef_vtbl;
-
-#define UPB_ONEOFDEF_INIT(name, ntof, itof, refs, ref2s) \
-  { UPB_REFCOUNT_INIT(&upb_oneofdef_vtbl, refs, ref2s), 0, name, ntof, itof }
-
-
-/* upb_symtab *****************************************************************/
-
-struct upb_symtab {
-  upb_refcounted base;
-
-  upb_strtable symtab;
-};
-
-struct upb_filedef {
-  upb_refcounted base;
-
-  const char *name;
-  const char *package;
-  const char *phpprefix;
-  const char *phpnamespace;
-  upb_syntax_t syntax;
-
-  upb_inttable defs;
-  upb_inttable deps;
-};
-
-extern const struct upb_refcounted_vtbl upb_filedef_vtbl;
-
-#endif  /* UPB_STATICINIT_H_ */
-
 
 #ifndef UPB_MSGFACTORY_H_
 #define UPB_MSGFACTORY_H_
 
-UPB_DECLARE_TYPE(upb::MessageFactory, upb_msgfactory)
-
 /** upb_msgfactory ************************************************************/
 
+struct upb_msgfactory;
+typedef struct upb_msgfactory upb_msgfactory;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* A upb_msgfactory contains a cache of upb_msglayout, upb_handlers, and
  * upb_visitorplan objects.  These are the objects necessary to represent,
  * populate, and and visit upb_msg objects.
@@ -7831,698 +6152,12 @@
 const upb_msglayout *upb_msgfactory_getlayout(upb_msgfactory *f,
                                               const upb_msgdef *m);
 
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
 
 #endif /* UPB_MSGFACTORY_H_ */
 /*
-** upb::descriptor::Reader (upb_descreader)
-**
-** Provides a way of building upb::Defs from data in descriptor.proto format.
-*/
-
-#ifndef UPB_DESCRIPTOR_H
-#define UPB_DESCRIPTOR_H
-
-
-#ifdef __cplusplus
-namespace upb {
-namespace descriptor {
-class Reader;
-}  /* namespace descriptor */
-}  /* namespace upb */
-#endif
-
-UPB_DECLARE_TYPE(upb::descriptor::Reader, upb_descreader)
-
-#ifdef __cplusplus
-
-/* Class that receives descriptor data according to the descriptor.proto schema
- * and use it to build upb::Defs corresponding to that schema. */
-class upb::descriptor::Reader {
- public:
-  /* These handlers must have come from NewHandlers() and must outlive the
-   * Reader.
-   *
-   * TODO: generate the handlers statically (like we do with the
-   * descriptor.proto defs) so that there is no need to pass this parameter (or
-   * to build/memory-manage the handlers at runtime at all).  Unfortunately this
-   * is a bit tricky to implement for Handlers, but necessary to simplify this
-   * interface. */
-  static Reader* Create(Environment* env, const Handlers* handlers);
-
-  /* The reader's input; this is where descriptor.proto data should be sent. */
-  Sink* input();
-
-  /* Use to get the FileDefs that have been parsed. */
-  size_t file_count() const;
-  FileDef* file(size_t i) const;
-
-  /* Builds and returns handlers for the reader, owned by "owner." */
-  static Handlers* NewHandlers(const void* owner);
-
- private:
-  UPB_DISALLOW_POD_OPS(Reader, upb::descriptor::Reader)
-};
-
-#endif
-
-UPB_BEGIN_EXTERN_C
-
-/* C API. */
-upb_descreader *upb_descreader_create(upb_env *e, const upb_handlers *h);
-upb_sink *upb_descreader_input(upb_descreader *r);
-size_t upb_descreader_filecount(const upb_descreader *r);
-upb_filedef *upb_descreader_file(const upb_descreader *r, size_t i);
-const upb_handlers *upb_descreader_newhandlers(const void *owner);
-
-UPB_END_EXTERN_C
-
-#ifdef __cplusplus
-/* C++ implementation details. ************************************************/
-namespace upb {
-namespace descriptor {
-inline Reader* Reader::Create(Environment* e, const Handlers *h) {
-  return upb_descreader_create(e, h);
-}
-inline Sink* Reader::input() { return upb_descreader_input(this); }
-inline size_t Reader::file_count() const {
-  return upb_descreader_filecount(this);
-}
-inline FileDef* Reader::file(size_t i) const {
-  return upb_descreader_file(this, i);
-}
-}  /* namespace descriptor */
-}  /* namespace upb */
-#endif
-
-#endif  /* UPB_DESCRIPTOR_H */
-/* This file contains accessors for a set of compiled-in defs.
- * Note that unlike Google's protobuf, it does *not* define
- * generated classes or any other kind of data structure for
- * actually storing protobufs.  It only contains *defs* which
- * let you reflect over a protobuf *schema*.
- */
-/* This file was generated by upbc (the upb compiler) from the input
- * file:
- *
- *     upb/descriptor/descriptor.proto
- *
- * Do not edit -- your changes will be discarded when the file is
- * regenerated. */
-
-#ifndef UPB_DESCRIPTOR_DESCRIPTOR_PROTO_UPB_H_
-#define UPB_DESCRIPTOR_DESCRIPTOR_PROTO_UPB_H_
-
-
-UPB_BEGIN_EXTERN_C
-
-/* MessageDefs: call these functions to get a ref to a msgdef. */
-const upb_msgdef *upbdefs_google_protobuf_DescriptorProto_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_EnumDescriptorProto_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_EnumOptions_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_EnumValueDescriptorProto_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_EnumValueOptions_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_FieldDescriptorProto_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_FieldOptions_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_FileDescriptorProto_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_FileDescriptorSet_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_FileOptions_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_MessageOptions_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_MethodDescriptorProto_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_MethodOptions_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_OneofDescriptorProto_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_ServiceDescriptorProto_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_ServiceOptions_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_SourceCodeInfo_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_SourceCodeInfo_Location_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_UninterpretedOption_get(const void *owner);
-const upb_msgdef *upbdefs_google_protobuf_UninterpretedOption_NamePart_get(const void *owner);
-
-/* EnumDefs: call these functions to get a ref to an enumdef. */
-const upb_enumdef *upbdefs_google_protobuf_FieldDescriptorProto_Label_get(const void *owner);
-const upb_enumdef *upbdefs_google_protobuf_FieldDescriptorProto_Type_get(const void *owner);
-const upb_enumdef *upbdefs_google_protobuf_FieldOptions_CType_get(const void *owner);
-const upb_enumdef *upbdefs_google_protobuf_FieldOptions_JSType_get(const void *owner);
-const upb_enumdef *upbdefs_google_protobuf_FileOptions_OptimizeMode_get(const void *owner);
-
-/* Functions to test whether this message is of a certain type. */
-UPB_INLINE bool upbdefs_google_protobuf_DescriptorProto_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.DescriptorProto") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.DescriptorProto.ExtensionRange") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.DescriptorProto.ReservedRange") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_EnumDescriptorProto_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.EnumDescriptorProto") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_EnumOptions_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.EnumOptions") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_EnumValueDescriptorProto_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.EnumValueDescriptorProto") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_EnumValueOptions_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.EnumValueOptions") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_FieldDescriptorProto_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.FieldDescriptorProto") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_FieldOptions_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.FieldOptions") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_FileDescriptorProto_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.FileDescriptorProto") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_FileDescriptorSet_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.FileDescriptorSet") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_FileOptions_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.FileOptions") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_MessageOptions_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.MessageOptions") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_MethodDescriptorProto_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.MethodDescriptorProto") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_MethodOptions_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.MethodOptions") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_OneofDescriptorProto_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.OneofDescriptorProto") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_ServiceDescriptorProto_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.ServiceDescriptorProto") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_ServiceOptions_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.ServiceOptions") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_SourceCodeInfo_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.SourceCodeInfo") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_SourceCodeInfo_Location_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.SourceCodeInfo.Location") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_UninterpretedOption_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.UninterpretedOption") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_UninterpretedOption_NamePart_is(const upb_msgdef *m) {
-  return strcmp(upb_msgdef_fullname(m), "google.protobuf.UninterpretedOption.NamePart") == 0;
-}
-
-/* Functions to test whether this enum is of a certain type. */
-UPB_INLINE bool upbdefs_google_protobuf_FieldDescriptorProto_Label_is(const upb_enumdef *e) {
-  return strcmp(upb_enumdef_fullname(e), "google.protobuf.FieldDescriptorProto.Label") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_FieldDescriptorProto_Type_is(const upb_enumdef *e) {
-  return strcmp(upb_enumdef_fullname(e), "google.protobuf.FieldDescriptorProto.Type") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_FieldOptions_CType_is(const upb_enumdef *e) {
-  return strcmp(upb_enumdef_fullname(e), "google.protobuf.FieldOptions.CType") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_FieldOptions_JSType_is(const upb_enumdef *e) {
-  return strcmp(upb_enumdef_fullname(e), "google.protobuf.FieldOptions.JSType") == 0;
-}
-UPB_INLINE bool upbdefs_google_protobuf_FileOptions_OptimizeMode_is(const upb_enumdef *e) {
-  return strcmp(upb_enumdef_fullname(e), "google.protobuf.FileOptions.OptimizeMode") == 0;
-}
-
-
-/* Functions to get a fielddef from a msgdef reference. */
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_f_end(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_f_start(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_f_end(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_f_start(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_enum_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_extension(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_extension_range(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_field(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_nested_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_oneof_decl(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 7); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_reserved_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_reserved_range(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 9); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_f_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_f_allow_alias(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumOptions_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumOptions_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_f_number(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumValueOptions_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_EnumValueOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_default_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 7); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_extendee(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_json_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_label(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_number(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_oneof_index(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 9); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_type_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_ctype(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_jstype(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_lazy(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_packed(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_weak(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_dependency(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_enum_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_extension(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 7); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_message_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_package(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_public_dependency(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_service(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_source_code_info(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 9); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_syntax(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 12); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_weak_dependency(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 11); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorSet_f_file(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorSet_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_cc_enable_arenas(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 31); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_cc_generic_services(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 16); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_csharp_namespace(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 37); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 23); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_go_package(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 11); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_generate_equals_and_hash(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 20); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_generic_services(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 17); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_multiple_files(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_outer_classname(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_package(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_string_check_utf8(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 27); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_javanano_use_deprecated_package(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 38); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_objc_class_prefix(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 36); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_optimize_for(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 9); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_php_class_prefix(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 40); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_php_namespace(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 41); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_py_generic_services(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 18); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_map_entry(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 7); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_message_set_wire_format(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_no_standard_descriptor_accessor(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_client_streaming(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_input_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_output_type(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_server_streaming(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodOptions_is(m)); return upb_msgdef_itof(m, 33); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_MethodOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_OneofDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_OneofDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_f_method(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_ServiceDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_ServiceDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_f_options(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_ServiceDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceOptions_f_deprecated(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_ServiceOptions_is(m)); return upb_msgdef_itof(m, 33); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceOptions_f_uninterpreted_option(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_ServiceOptions_is(m)); return upb_msgdef_itof(m, 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_leading_comments(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_leading_detached_comments(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_path(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_span(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_trailing_comments(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_f_location(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_NamePart_f_is_extension(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_NamePart_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_NamePart_f_name_part(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_NamePart_is(m)); return upb_msgdef_itof(m, 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_aggregate_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_double_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_identifier_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_name(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_negative_int_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_positive_int_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_string_value(const upb_msgdef *m) { UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 7); }
-
-UPB_END_EXTERN_C
-
-#ifdef __cplusplus
-
-namespace upbdefs {
-namespace google {
-namespace protobuf {
-
-class DescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  DescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_is(m));
-  }
-
-  static DescriptorProto get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_DescriptorProto_get(&m);
-    return DescriptorProto(m, &m);
-  }
-
-  class ExtensionRange : public ::upb::reffed_ptr<const ::upb::MessageDef> {
-   public:
-    ExtensionRange(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-        : reffed_ptr(m, ref_donor) {
-      UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(m));
-    }
-
-    static ExtensionRange get() {
-      const ::upb::MessageDef* m = upbdefs_google_protobuf_DescriptorProto_ExtensionRange_get(&m);
-      return ExtensionRange(m, &m);
-    }
-  };
-
-  class ReservedRange : public ::upb::reffed_ptr<const ::upb::MessageDef> {
-   public:
-    ReservedRange(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-        : reffed_ptr(m, ref_donor) {
-      UPB_ASSERT(upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(m));
-    }
-
-    static ReservedRange get() {
-      const ::upb::MessageDef* m = upbdefs_google_protobuf_DescriptorProto_ReservedRange_get(&m);
-      return ReservedRange(m, &m);
-    }
-  };
-};
-
-class EnumDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  EnumDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_EnumDescriptorProto_is(m));
-  }
-
-  static EnumDescriptorProto get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_EnumDescriptorProto_get(&m);
-    return EnumDescriptorProto(m, &m);
-  }
-};
-
-class EnumOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  EnumOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_EnumOptions_is(m));
-  }
-
-  static EnumOptions get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_EnumOptions_get(&m);
-    return EnumOptions(m, &m);
-  }
-};
-
-class EnumValueDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  EnumValueDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m));
-  }
-
-  static EnumValueDescriptorProto get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_EnumValueDescriptorProto_get(&m);
-    return EnumValueDescriptorProto(m, &m);
-  }
-};
-
-class EnumValueOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  EnumValueOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_EnumValueOptions_is(m));
-  }
-
-  static EnumValueOptions get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_EnumValueOptions_get(&m);
-    return EnumValueOptions(m, &m);
-  }
-};
-
-class FieldDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  FieldDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_is(m));
-  }
-
-  static FieldDescriptorProto get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_FieldDescriptorProto_get(&m);
-    return FieldDescriptorProto(m, &m);
-  }
-
-  class Label : public ::upb::reffed_ptr<const ::upb::EnumDef> {
-   public:
-    Label(const ::upb::EnumDef* e, const void *ref_donor = NULL)
-        : reffed_ptr(e, ref_donor) {
-      UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_Label_is(e));
-    }
-    static Label get() {
-      const ::upb::EnumDef* e = upbdefs_google_protobuf_FieldDescriptorProto_Label_get(&e);
-      return Label(e, &e);
-    }
-  };
-
-  class Type : public ::upb::reffed_ptr<const ::upb::EnumDef> {
-   public:
-    Type(const ::upb::EnumDef* e, const void *ref_donor = NULL)
-        : reffed_ptr(e, ref_donor) {
-      UPB_ASSERT(upbdefs_google_protobuf_FieldDescriptorProto_Type_is(e));
-    }
-    static Type get() {
-      const ::upb::EnumDef* e = upbdefs_google_protobuf_FieldDescriptorProto_Type_get(&e);
-      return Type(e, &e);
-    }
-  };
-};
-
-class FieldOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  FieldOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_is(m));
-  }
-
-  static FieldOptions get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_FieldOptions_get(&m);
-    return FieldOptions(m, &m);
-  }
-
-  class CType : public ::upb::reffed_ptr<const ::upb::EnumDef> {
-   public:
-    CType(const ::upb::EnumDef* e, const void *ref_donor = NULL)
-        : reffed_ptr(e, ref_donor) {
-      UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_CType_is(e));
-    }
-    static CType get() {
-      const ::upb::EnumDef* e = upbdefs_google_protobuf_FieldOptions_CType_get(&e);
-      return CType(e, &e);
-    }
-  };
-
-  class JSType : public ::upb::reffed_ptr<const ::upb::EnumDef> {
-   public:
-    JSType(const ::upb::EnumDef* e, const void *ref_donor = NULL)
-        : reffed_ptr(e, ref_donor) {
-      UPB_ASSERT(upbdefs_google_protobuf_FieldOptions_JSType_is(e));
-    }
-    static JSType get() {
-      const ::upb::EnumDef* e = upbdefs_google_protobuf_FieldOptions_JSType_get(&e);
-      return JSType(e, &e);
-    }
-  };
-};
-
-class FileDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  FileDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorProto_is(m));
-  }
-
-  static FileDescriptorProto get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_FileDescriptorProto_get(&m);
-    return FileDescriptorProto(m, &m);
-  }
-};
-
-class FileDescriptorSet : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  FileDescriptorSet(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_FileDescriptorSet_is(m));
-  }
-
-  static FileDescriptorSet get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_FileDescriptorSet_get(&m);
-    return FileDescriptorSet(m, &m);
-  }
-};
-
-class FileOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  FileOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_FileOptions_is(m));
-  }
-
-  static FileOptions get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_FileOptions_get(&m);
-    return FileOptions(m, &m);
-  }
-
-  class OptimizeMode : public ::upb::reffed_ptr<const ::upb::EnumDef> {
-   public:
-    OptimizeMode(const ::upb::EnumDef* e, const void *ref_donor = NULL)
-        : reffed_ptr(e, ref_donor) {
-      UPB_ASSERT(upbdefs_google_protobuf_FileOptions_OptimizeMode_is(e));
-    }
-    static OptimizeMode get() {
-      const ::upb::EnumDef* e = upbdefs_google_protobuf_FileOptions_OptimizeMode_get(&e);
-      return OptimizeMode(e, &e);
-    }
-  };
-};
-
-class MessageOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  MessageOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_MessageOptions_is(m));
-  }
-
-  static MessageOptions get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_MessageOptions_get(&m);
-    return MessageOptions(m, &m);
-  }
-};
-
-class MethodDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  MethodDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_MethodDescriptorProto_is(m));
-  }
-
-  static MethodDescriptorProto get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_MethodDescriptorProto_get(&m);
-    return MethodDescriptorProto(m, &m);
-  }
-};
-
-class MethodOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  MethodOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_MethodOptions_is(m));
-  }
-
-  static MethodOptions get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_MethodOptions_get(&m);
-    return MethodOptions(m, &m);
-  }
-};
-
-class OneofDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  OneofDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_OneofDescriptorProto_is(m));
-  }
-
-  static OneofDescriptorProto get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_OneofDescriptorProto_get(&m);
-    return OneofDescriptorProto(m, &m);
-  }
-};
-
-class ServiceDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  ServiceDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_ServiceDescriptorProto_is(m));
-  }
-
-  static ServiceDescriptorProto get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_ServiceDescriptorProto_get(&m);
-    return ServiceDescriptorProto(m, &m);
-  }
-};
-
-class ServiceOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  ServiceOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_ServiceOptions_is(m));
-  }
-
-  static ServiceOptions get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_ServiceOptions_get(&m);
-    return ServiceOptions(m, &m);
-  }
-};
-
-class SourceCodeInfo : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  SourceCodeInfo(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_is(m));
-  }
-
-  static SourceCodeInfo get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_SourceCodeInfo_get(&m);
-    return SourceCodeInfo(m, &m);
-  }
-
-  class Location : public ::upb::reffed_ptr<const ::upb::MessageDef> {
-   public:
-    Location(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-        : reffed_ptr(m, ref_donor) {
-      UPB_ASSERT(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m));
-    }
-
-    static Location get() {
-      const ::upb::MessageDef* m = upbdefs_google_protobuf_SourceCodeInfo_Location_get(&m);
-      return Location(m, &m);
-    }
-  };
-};
-
-class UninterpretedOption : public ::upb::reffed_ptr<const ::upb::MessageDef> {
- public:
-  UninterpretedOption(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-      : reffed_ptr(m, ref_donor) {
-    UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_is(m));
-  }
-
-  static UninterpretedOption get() {
-    const ::upb::MessageDef* m = upbdefs_google_protobuf_UninterpretedOption_get(&m);
-    return UninterpretedOption(m, &m);
-  }
-
-  class NamePart : public ::upb::reffed_ptr<const ::upb::MessageDef> {
-   public:
-    NamePart(const ::upb::MessageDef* m, const void *ref_donor = NULL)
-        : reffed_ptr(m, ref_donor) {
-      UPB_ASSERT(upbdefs_google_protobuf_UninterpretedOption_NamePart_is(m));
-    }
-
-    static NamePart get() {
-      const ::upb::MessageDef* m = upbdefs_google_protobuf_UninterpretedOption_NamePart_get(&m);
-      return NamePart(m, &m);
-    }
-  };
-};
-
-}  /* namespace protobuf */
-}  /* namespace google */
-}  /* namespace upbdefs */
-
-#endif  /* __cplusplus */
-
-#endif  /* UPB_DESCRIPTOR_DESCRIPTOR_PROTO_UPB_H_ */
-/*
 ** Internal-only definitions for the decoder.
 */
 
@@ -8551,20 +6186,13 @@
 namespace upb {
 namespace pb {
 class CodeCache;
-class Decoder;
-class DecoderMethod;
+class DecoderPtr;
+class DecoderMethodPtr;
 class DecoderMethodOptions;
 }  /* namespace pb */
 }  /* namespace upb */
 #endif
 
-UPB_DECLARE_TYPE(upb::pb::CodeCache, upb_pbcodecache)
-UPB_DECLARE_TYPE(upb::pb::Decoder, upb_pbdecoder)
-UPB_DECLARE_TYPE(upb::pb::DecoderMethodOptions, upb_pbdecodermethodopts)
-
-UPB_DECLARE_DERIVED_TYPE(upb::pb::DecoderMethod, upb::RefCounted,
-                         upb_pbdecodermethod, upb_refcounted)
-
 /* The maximum number of bytes we are required to buffer internally between
  * calls to the decoder.  The value is 14: a 5 byte unknown tag plus ten-byte
  * varint, less one because we are buffering an incomplete value.
@@ -8572,83 +6200,111 @@
  * Should only be used by unit tests. */
 #define UPB_DECODER_MAX_RESIDUAL_BYTES 14
 
+/* upb_pbdecodermethod ********************************************************/
+
+struct upb_pbdecodermethod;
+typedef struct upb_pbdecodermethod upb_pbdecodermethod;
+
 #ifdef __cplusplus
-
-/* The parameters one uses to construct a DecoderMethod.
- * TODO(haberman): move allowjit here?  Seems more convenient for users.
- * TODO(haberman): move this to be heap allocated for ABI stability. */
-class upb::pb::DecoderMethodOptions {
- public:
-  /* Parameter represents the destination handlers that this method will push
-   * to. */
-  explicit DecoderMethodOptions(const Handlers* dest_handlers);
-
-  /* Should the decoder push submessages to lazy handlers for fields that have
-   * them?  The caller should set this iff the lazy handlers expect data that is
-   * in protobuf binary format and the caller wishes to lazy parse it. */
-  void set_lazy(bool lazy);
-#else
-struct upb_pbdecodermethodopts {
+extern "C" {
 #endif
-  const upb_handlers *handlers;
-  bool lazy;
-};
+
+const upb_handlers *upb_pbdecodermethod_desthandlers(
+    const upb_pbdecodermethod *m);
+const upb_byteshandler *upb_pbdecodermethod_inputhandler(
+    const upb_pbdecodermethod *m);
+bool upb_pbdecodermethod_isnative(const upb_pbdecodermethod *m);
 
 #ifdef __cplusplus
+}  /* extern "C" */
 
 /* Represents the code to parse a protobuf according to a destination
  * Handlers. */
-class upb::pb::DecoderMethod {
+class upb::pb::DecoderMethodPtr {
  public:
-  /* Include base methods from upb::ReferenceCounted. */
-  UPB_REFCOUNTED_CPPMETHODS
+  DecoderMethodPtr() : ptr_(nullptr) {}
+  DecoderMethodPtr(const upb_pbdecodermethod* ptr) : ptr_(ptr) {}
+
+  const upb_pbdecodermethod* ptr() { return ptr_; }
 
   /* The destination handlers that are statically bound to this method.
    * This method is only capable of outputting to a sink that uses these
    * handlers. */
-  const Handlers* dest_handlers() const;
+  const Handlers *dest_handlers() const {
+    return upb_pbdecodermethod_desthandlers(ptr_);
+  }
 
   /* The input handlers for this decoder method. */
-  const BytesHandler* input_handler() const;
+  const BytesHandler* input_handler() const {
+    return upb_pbdecodermethod_inputhandler(ptr_);
+  }
 
   /* Whether this method is native. */
-  bool is_native() const;
-
-  /* Convenience method for generating a DecoderMethod without explicitly
-   * creating a CodeCache. */
-  static reffed_ptr<const DecoderMethod> New(const DecoderMethodOptions& opts);
+  bool is_native() const {
+    return upb_pbdecodermethod_isnative(ptr_);
+  }
 
  private:
-  UPB_DISALLOW_POD_OPS(DecoderMethod, upb::pb::DecoderMethod)
+  const upb_pbdecodermethod* ptr_;
 };
 
 #endif
 
+/* upb_pbdecoder **************************************************************/
+
 /* Preallocation hint: decoder won't allocate more bytes than this when first
  * constructed.  This hint may be an overestimate for some build configurations.
  * But if the decoder library is upgraded without recompiling the application,
  * it may be an underestimate. */
 #define UPB_PB_DECODER_SIZE 4416
 
+struct upb_pbdecoder;
+typedef struct upb_pbdecoder upb_pbdecoder;
+
 #ifdef __cplusplus
+extern "C" {
+#endif
+
+upb_pbdecoder *upb_pbdecoder_create(upb_arena *arena,
+                                    const upb_pbdecodermethod *method,
+                                    upb_sink output, upb_status *status);
+const upb_pbdecodermethod *upb_pbdecoder_method(const upb_pbdecoder *d);
+upb_bytessink upb_pbdecoder_input(upb_pbdecoder *d);
+uint64_t upb_pbdecoder_bytesparsed(const upb_pbdecoder *d);
+size_t upb_pbdecoder_maxnesting(const upb_pbdecoder *d);
+bool upb_pbdecoder_setmaxnesting(upb_pbdecoder *d, size_t max);
+void upb_pbdecoder_reset(upb_pbdecoder *d);
+
+#ifdef __cplusplus
+}  /* extern "C" */
 
 /* A Decoder receives binary protobuf data on its input sink and pushes the
  * decoded data to its output sink. */
-class upb::pb::Decoder {
+class upb::pb::DecoderPtr {
  public:
+  DecoderPtr() : ptr_(nullptr) {}
+  DecoderPtr(upb_pbdecoder* ptr) : ptr_(ptr) {}
+
+  upb_pbdecoder* ptr() { return ptr_; }
+
   /* Constructs a decoder instance for the given method, which must outlive this
    * decoder.  Any errors during parsing will be set on the given status, which
    * must also outlive this decoder.
    *
    * The sink must match the given method. */
-  static Decoder* Create(Environment* env, const DecoderMethod* method,
-                         Sink* output);
+  static DecoderPtr Create(Arena *arena, DecoderMethodPtr method,
+                           upb::Sink output, Status *status) {
+    return DecoderPtr(upb_pbdecoder_create(arena->ptr(), method.ptr(),
+                                           output.sink(), status->ptr()));
+  }
 
   /* Returns the DecoderMethod this decoder is parsing from. */
-  const DecoderMethod* method() const;
+  const DecoderMethodPtr method() const {
+    return DecoderMethodPtr(upb_pbdecoder_method(ptr_));
+  }
 
   /* The sink on which this decoder receives input. */
-  BytesSink* input();
+  BytesSink input() { return BytesSink(upb_pbdecoder_input(ptr())); }
 
   /* Returns number of bytes successfully parsed.
    *
@@ -8657,7 +6313,7 @@
    *
    * This value may not be up-to-date when called from inside a parsing
    * callback. */
-  uint64_t BytesParsed() const;
+  uint64_t BytesParsed() { return upb_pbdecoder_bytesparsed(ptr()); }
 
   /* Gets/sets the parsing nexting limit.  If the total number of nested
    * submessages and repeated fields hits this limit, parsing will fail.  This
@@ -8666,31 +6322,55 @@
    *
    * Setting the limit will fail if the parser is currently suspended at a depth
    * greater than this, or if memory allocation of the stack fails. */
-  size_t max_nesting() const;
-  bool set_max_nesting(size_t max);
+  size_t max_nesting() { return upb_pbdecoder_maxnesting(ptr()); }
+  bool set_max_nesting(size_t max) { return upb_pbdecoder_maxnesting(ptr()); }
 
-  void Reset();
+  void Reset() { upb_pbdecoder_reset(ptr()); }
 
   static const size_t kSize = UPB_PB_DECODER_SIZE;
 
  private:
-  UPB_DISALLOW_POD_OPS(Decoder, upb::pb::Decoder)
+  upb_pbdecoder *ptr_;
 };
 
 #endif  /* __cplusplus */
 
+/* upb_pbcodecache ************************************************************/
+
+/* Lazily builds and caches decoder methods that will push data to the given
+ * handlers.  The destination handlercache must outlive this object. */
+
+struct upb_pbcodecache;
+typedef struct upb_pbcodecache upb_pbcodecache;
+
 #ifdef __cplusplus
+extern "C" {
+#endif
+
+upb_pbcodecache *upb_pbcodecache_new(upb_handlercache *dest);
+void upb_pbcodecache_free(upb_pbcodecache *c);
+bool upb_pbcodecache_allowjit(const upb_pbcodecache *c);
+void upb_pbcodecache_setallowjit(upb_pbcodecache *c, bool allow);
+void upb_pbcodecache_setlazy(upb_pbcodecache *c, bool lazy);
+const upb_pbdecodermethod *upb_pbcodecache_get(upb_pbcodecache *c,
+                                               const upb_msgdef *md);
+
+#ifdef __cplusplus
+}  /* extern "C" */
 
 /* A class for caching protobuf processing code, whether bytecode for the
  * interpreted decoder or machine code for the JIT.
  *
- * This class is not thread-safe.
- *
- * TODO(haberman): move this to be heap allocated for ABI stability. */
+ * This class is not thread-safe. */
 class upb::pb::CodeCache {
  public:
-  CodeCache();
-  ~CodeCache();
+  CodeCache(upb::HandlerCache *dest)
+      : ptr_(upb_pbcodecache_new(dest->ptr()), upb_pbcodecache_free) {}
+  CodeCache(CodeCache&&) = default;
+  CodeCache& operator=(CodeCache&&) = default;
+
+  upb_pbcodecache* ptr() { return ptr_.get(); }
+  const upb_pbcodecache* ptr() const { return ptr_.get(); }
 
   /* Whether the cache is allowed to generate machine code.  Defaults to true.
    * There is no real reason to turn it off except for testing or if you are
@@ -8699,159 +6379,31 @@
    * Note that allow_jit = true does not *guarantee* that the code will be JIT
    * compiled.  If this platform is not supported or the JIT was not compiled
    * in, the code may still be interpreted. */
-  bool allow_jit() const;
+  bool allow_jit() const { return upb_pbcodecache_allowjit(ptr()); }
 
   /* This may only be called when the object is first constructed, and prior to
-   * any code generation, otherwise returns false and does nothing. */
-  bool set_allow_jit(bool allow);
+   * any code generation. */
+  void set_allow_jit(bool allow) { upb_pbcodecache_setallowjit(ptr(), allow); }
+
+  /* Should the decoder push submessages to lazy handlers for fields that have
+   * them?  The caller should set this iff the lazy handlers expect data that is
+   * in protobuf binary format and the caller wishes to lazy parse it. */
+  void set_lazy(bool lazy) { upb_pbcodecache_setlazy(ptr(), lazy); }
 
   /* Returns a DecoderMethod that can push data to the given handlers.
-   * If a suitable method already exists, it will be returned from the cache.
-   *
-   * Specifying the destination handlers here allows the DecoderMethod to be
-   * statically bound to the destination handlers if possible, which can allow
-   * more efficient decoding.  However the returned method may or may not
-   * actually be statically bound.  But in all cases, the returned method can
-   * push data to the given handlers. */
-  const DecoderMethod *GetDecoderMethod(const DecoderMethodOptions& opts);
-
-  /* If/when someone needs to explicitly create a dynamically-bound
-   * DecoderMethod*, we can add a method to get it here. */
+   * If a suitable method already exists, it will be returned from the cache. */
+  const DecoderMethodPtr Get(MessageDefPtr md) {
+    return DecoderMethodPtr(upb_pbcodecache_get(ptr(), md.ptr()));
+  }
 
  private:
-  UPB_DISALLOW_COPY_AND_ASSIGN(CodeCache)
-#else
-struct upb_pbcodecache {
-#endif
-  bool allow_jit_;
-
-  /* Array of mgroups. */
-  upb_inttable groups;
+  std::unique_ptr<upb_pbcodecache, decltype(&upb_pbcodecache_free)> ptr_;
 };
 
-UPB_BEGIN_EXTERN_C
-
-upb_pbdecoder *upb_pbdecoder_create(upb_env *e,
-                                    const upb_pbdecodermethod *method,
-                                    upb_sink *output);
-const upb_pbdecodermethod *upb_pbdecoder_method(const upb_pbdecoder *d);
-upb_bytessink *upb_pbdecoder_input(upb_pbdecoder *d);
-uint64_t upb_pbdecoder_bytesparsed(const upb_pbdecoder *d);
-size_t upb_pbdecoder_maxnesting(const upb_pbdecoder *d);
-bool upb_pbdecoder_setmaxnesting(upb_pbdecoder *d, size_t max);
-void upb_pbdecoder_reset(upb_pbdecoder *d);
-
-void upb_pbdecodermethodopts_init(upb_pbdecodermethodopts *opts,
-                                  const upb_handlers *h);
-void upb_pbdecodermethodopts_setlazy(upb_pbdecodermethodopts *opts, bool lazy);
-
-
-/* Include refcounted methods like upb_pbdecodermethod_ref(). */
-UPB_REFCOUNTED_CMETHODS(upb_pbdecodermethod, upb_pbdecodermethod_upcast)
-
-const upb_handlers *upb_pbdecodermethod_desthandlers(
-    const upb_pbdecodermethod *m);
-const upb_byteshandler *upb_pbdecodermethod_inputhandler(
-    const upb_pbdecodermethod *m);
-bool upb_pbdecodermethod_isnative(const upb_pbdecodermethod *m);
-const upb_pbdecodermethod *upb_pbdecodermethod_new(
-    const upb_pbdecodermethodopts *opts, const void *owner);
-
-void upb_pbcodecache_init(upb_pbcodecache *c);
-void upb_pbcodecache_uninit(upb_pbcodecache *c);
-bool upb_pbcodecache_allowjit(const upb_pbcodecache *c);
-bool upb_pbcodecache_setallowjit(upb_pbcodecache *c, bool allow);
-const upb_pbdecodermethod *upb_pbcodecache_getdecodermethod(
-    upb_pbcodecache *c, const upb_pbdecodermethodopts *opts);
-
-UPB_END_EXTERN_C
-
-#ifdef __cplusplus
-
-namespace upb {
-
-namespace pb {
-
-/* static */
-inline Decoder* Decoder::Create(Environment* env, const DecoderMethod* m,
-                                Sink* sink) {
-  return upb_pbdecoder_create(env, m, sink);
-}
-inline const DecoderMethod* Decoder::method() const {
-  return upb_pbdecoder_method(this);
-}
-inline BytesSink* Decoder::input() {
-  return upb_pbdecoder_input(this);
-}
-inline uint64_t Decoder::BytesParsed() const {
-  return upb_pbdecoder_bytesparsed(this);
-}
-inline size_t Decoder::max_nesting() const {
-  return upb_pbdecoder_maxnesting(this);
-}
-inline bool Decoder::set_max_nesting(size_t max) {
-  return upb_pbdecoder_setmaxnesting(this, max);
-}
-inline void Decoder::Reset() { upb_pbdecoder_reset(this); }
-
-inline DecoderMethodOptions::DecoderMethodOptions(const Handlers* h) {
-  upb_pbdecodermethodopts_init(this, h);
-}
-inline void DecoderMethodOptions::set_lazy(bool lazy) {
-  upb_pbdecodermethodopts_setlazy(this, lazy);
-}
-
-inline const Handlers* DecoderMethod::dest_handlers() const {
-  return upb_pbdecodermethod_desthandlers(this);
-}
-inline const BytesHandler* DecoderMethod::input_handler() const {
-  return upb_pbdecodermethod_inputhandler(this);
-}
-inline bool DecoderMethod::is_native() const {
-  return upb_pbdecodermethod_isnative(this);
-}
-/* static */
-inline reffed_ptr<const DecoderMethod> DecoderMethod::New(
-    const DecoderMethodOptions &opts) {
-  const upb_pbdecodermethod *m = upb_pbdecodermethod_new(&opts, &m);
-  return reffed_ptr<const DecoderMethod>(m, &m);
-}
-
-inline CodeCache::CodeCache() {
-  upb_pbcodecache_init(this);
-}
-inline CodeCache::~CodeCache() {
-  upb_pbcodecache_uninit(this);
-}
-inline bool CodeCache::allow_jit() const {
-  return upb_pbcodecache_allowjit(this);
-}
-inline bool CodeCache::set_allow_jit(bool allow) {
-  return upb_pbcodecache_setallowjit(this, allow);
-}
-inline const DecoderMethod *CodeCache::GetDecoderMethod(
-    const DecoderMethodOptions& opts) {
-  return upb_pbcodecache_getdecodermethod(this, &opts);
-}
-
-}  /* namespace pb */
-}  /* namespace upb */
-
 #endif  /* __cplusplus */
 
 #endif  /* UPB_DECODER_H_ */
 
-/* C++ names are not actually used since this type isn't exposed to users. */
-#ifdef __cplusplus
-namespace upb {
-namespace pb {
-class MessageGroup;
-}  /* namespace pb */
-}  /* namespace upb */
-#endif
-UPB_DECLARE_DERIVED_TYPE(upb::pb::MessageGroup, upb::RefCounted,
-                         mgroup, upb_refcounted)
-
 /* Opcode definitions.  The canonical meaning of each opcode is its
  * implementation in the interpreter (the JIT is written to match this).
  *
@@ -8911,32 +6463,27 @@
 
 #define OP_MAX OP_HALT
 
-UPB_INLINE opcode getop(uint32_t instr) { return instr & 0xff; }
+UPB_INLINE opcode getop(uint32_t instr) { return (opcode)(instr & 0xff); }
+
+struct upb_pbcodecache {
+  upb_arena *arena;
+  upb_handlercache *dest;
+  bool allow_jit;
+  bool lazy;
+
+  /* Array of mgroups. */
+  upb_inttable groups;
+};
 
 /* Method group; represents a set of decoder methods that had their code
- * emitted together, and must therefore be freed together.  Immutable once
- * created.  It is possible we may want to expose this to users at some point.
- *
- * Overall ownership of Decoder objects looks like this:
- *
- *                +----------+
- *                |          | <---> DecoderMethod
- *                | method   |
- * CodeCache ---> |  group   | <---> DecoderMethod
- *                |          |
- *                | (mgroup) | <---> DecoderMethod
- *                +----------+
- */
-struct mgroup {
-  upb_refcounted base;
-
-  /* Maps upb_msgdef/upb_handlers -> upb_pbdecodermethod.  We own refs on the
-   * methods. */
+ * emitted together.  Immutable once created.  */
+typedef struct {
+  /* Maps upb_msgdef/upb_handlers -> upb_pbdecodermethod.  Owned by us.
+   *
+   * Ideally this would be on pbcodecache (if we were actually caching code).
+   * Right now we don't actually cache anything, which is wasteful. */
   upb_inttable methods;
 
-  /* When we add the ability to link to previously existing mgroups, we'll
-   * need an array of mgroups we reference here, and own refs on them. */
-
   /* The bytecode for our methods, if any exists.  Owned by us. */
   uint32_t *bytecode;
   uint32_t *bytecode_end;
@@ -8949,7 +6496,7 @@
   char *debug_info;
   void *dl;
 #endif
-};
+} mgroup;
 
 /* The maximum that any submessages can be nested.  Matches proto2's limit.
  * This specifies the size of the decoder's statically-sized array and therefore
@@ -8989,8 +6536,6 @@
 } upb_pbdecoder_frame;
 
 struct upb_pbdecodermethod {
-  upb_refcounted base;
-
   /* While compiling, the base is relative in "ofs", after compiling it is
    * absolute in "ptr". */
   union {
@@ -8998,14 +6543,8 @@
     void *ptr;        /* Pointer to bytecode or machine code for this method. */
   } code_base;
 
-  /* The decoder method group to which this method belongs.  We own a ref.
-   * Owning a ref on the entire group is more coarse-grained than is strictly
-   * necessary; all we truly require is that methods we directly reference
-   * outlive us, while the group could contain many other messages we don't
-   * require.  But the group represents the messages that were
-   * allocated+compiled together, so it makes the most sense to free them
-   * together also. */
-  const upb_refcounted *group;
+  /* The decoder method group to which this method belongs. */
+  const mgroup *group;
 
   /* Whether this method is native code or bytecode. */
   bool is_native_;
@@ -9023,7 +6562,7 @@
 };
 
 struct upb_pbdecoder {
-  upb_env *env;
+  upb_arena *arena;
 
   /* Our input sink. */
   upb_bytessink input_;
@@ -9106,7 +6645,6 @@
 /* JIT codegen entry point. */
 void upb_pbdecoder_jit(mgroup *group);
 void upb_pbdecoder_freejit(mgroup *group);
-UPB_REFCOUNTED_CMETHODS(mgroup, mgroup_upcast)
 
 /* A special label that means "do field dispatch for this message and branch to
  * wherever that takes you." */
@@ -9317,150 +6855,71 @@
 #ifdef __cplusplus
 namespace upb {
 namespace pb {
-class Encoder;
+class EncoderPtr;
 }  /* namespace pb */
 }  /* namespace upb */
 #endif
 
-UPB_DECLARE_TYPE(upb::pb::Encoder, upb_pb_encoder)
-
 #define UPB_PBENCODER_MAX_NESTING 100
 
-/* upb::pb::Encoder ***********************************************************/
+/* upb_pb_encoder *************************************************************/
 
 /* Preallocation hint: decoder won't allocate more bytes than this when first
  * constructed.  This hint may be an overestimate for some build configurations.
  * But if the decoder library is upgraded without recompiling the application,
  * it may be an underestimate. */
-#define UPB_PB_ENCODER_SIZE 768
+#define UPB_PB_ENCODER_SIZE 784
+
+struct upb_pb_encoder;
+typedef struct upb_pb_encoder upb_pb_encoder;
 
 #ifdef __cplusplus
+extern "C" {
+#endif
 
-class upb::pb::Encoder {
+upb_sink upb_pb_encoder_input(upb_pb_encoder *p);
+upb_pb_encoder* upb_pb_encoder_create(upb_arena* a, const upb_handlers* h,
+                                      upb_bytessink output);
+
+/* Lazily builds and caches handlers that will push encoded data to a bytessink.
+ * Any msgdef objects used with this object must outlive it. */
+upb_handlercache *upb_pb_encoder_newcache();
+
+#ifdef __cplusplus
+}  /* extern "C" { */
+
+class upb::pb::EncoderPtr {
  public:
+  EncoderPtr(upb_pb_encoder* ptr) : ptr_(ptr) {}
+
+  upb_pb_encoder* ptr() { return ptr_; }
+
   /* Creates a new encoder in the given environment.  The Handlers must have
    * come from NewHandlers() below. */
-  static Encoder* Create(Environment* env, const Handlers* handlers,
-                         BytesSink* output);
+  static EncoderPtr Create(Arena* arena, const Handlers* handlers,
+                           BytesSink output) {
+    return EncoderPtr(
+        upb_pb_encoder_create(arena->ptr(), handlers, output.sink()));
+  }
 
   /* The input to the encoder. */
-  Sink* input();
+  upb::Sink input() { return upb_pb_encoder_input(ptr()); }
 
   /* Creates a new set of handlers for this MessageDef. */
-  static reffed_ptr<const Handlers> NewHandlers(const MessageDef* msg);
+  static HandlerCache NewCache() {
+    return HandlerCache(upb_pb_encoder_newcache());
+  }
 
   static const size_t kSize = UPB_PB_ENCODER_SIZE;
 
  private:
-  UPB_DISALLOW_POD_OPS(Encoder, upb::pb::Encoder)
+  upb_pb_encoder* ptr_;
 };
 
-#endif
-
-UPB_BEGIN_EXTERN_C
-
-const upb_handlers *upb_pb_encoder_newhandlers(const upb_msgdef *m,
-                                               const void *owner);
-upb_sink *upb_pb_encoder_input(upb_pb_encoder *p);
-upb_pb_encoder* upb_pb_encoder_create(upb_env* e, const upb_handlers* h,
-                                      upb_bytessink* output);
-
-UPB_END_EXTERN_C
-
-#ifdef __cplusplus
-
-namespace upb {
-namespace pb {
-inline Encoder* Encoder::Create(Environment* env, const Handlers* handlers,
-                                BytesSink* output) {
-  return upb_pb_encoder_create(env, handlers, output);
-}
-inline Sink* Encoder::input() {
-  return upb_pb_encoder_input(this);
-}
-inline reffed_ptr<const Handlers> Encoder::NewHandlers(
-    const upb::MessageDef *md) {
-  const Handlers* h = upb_pb_encoder_newhandlers(md, &h);
-  return reffed_ptr<const Handlers>(h, &h);
-}
-}  /* namespace pb */
-}  /* namespace upb */
-
-#endif
+#endif  /* __cplusplus */
 
 #endif  /* UPB_ENCODER_H_ */
 /*
-** upb's core components like upb_decoder and upb_msg are carefully designed to
-** avoid depending on each other for maximum orthogonality.  In other words,
-** you can use a upb_decoder to decode into *any* kind of structure; upb_msg is
-** just one such structure.  A upb_msg can be serialized/deserialized into any
-** format, protobuf binary format is just one such format.
-**
-** However, for convenience we provide functions here for doing common
-** operations like deserializing protobuf binary format into a upb_msg.  The
-** compromise is that this file drags in almost all of upb as a dependency,
-** which could be undesirable if you're trying to use a trimmed-down build of
-** upb.
-**
-** While these routines are convenient, they do not reuse any encoding/decoding
-** state.  For example, if a decoder is JIT-based, it will be re-JITted every
-** time these functions are called.  For this reason, if you are parsing lots
-** of data and efficiency is an issue, these may not be the best functions to
-** use (though they are useful for prototyping, before optimizing).
-*/
-
-#ifndef UPB_GLUE_H
-#define UPB_GLUE_H
-
-#include <stdbool.h>
-
-#ifdef __cplusplus
-#include <vector>
-
-extern "C" {
-#endif
-
-/* Loads a binary descriptor and returns a NULL-terminated array of unfrozen
- * filedefs.  The caller owns the returned array, which must be freed with
- * upb_gfree(). */
-upb_filedef **upb_loaddescriptor(const char *buf, size_t n, const void *owner,
-                                 upb_status *status);
-
-#ifdef __cplusplus
-}  /* extern "C" */
-
-namespace upb {
-
-inline bool LoadDescriptor(const char* buf, size_t n, Status* status,
-                           std::vector<reffed_ptr<FileDef> >* files) {
-  FileDef** parsed_files = upb_loaddescriptor(buf, n, &parsed_files, status);
-
-  if (parsed_files) {
-    FileDef** p = parsed_files;
-    while (*p) {
-      files->push_back(reffed_ptr<FileDef>(*p, &parsed_files));
-      ++p;
-    }
-    free(parsed_files);
-    return true;
-  } else {
-    return false;
-  }
-}
-
-/* Templated so it can accept both string and std::string. */
-template <typename T>
-bool LoadDescriptor(const T& desc, Status* status,
-                    std::vector<reffed_ptr<FileDef> >* files) {
-  return LoadDescriptor(desc.c_str(), desc.size(), status, files);
-}
-
-}  /* namespace upb */
-
-#endif
-
-#endif  /* UPB_GLUE_H */
-/*
 ** upb::pb::TextPrinter (upb_textprinter)
 **
 ** Handlers for writing to protobuf text format.
@@ -9473,71 +6932,60 @@
 #ifdef __cplusplus
 namespace upb {
 namespace pb {
-class TextPrinter;
+class TextPrinterPtr;
 }  /* namespace pb */
 }  /* namespace upb */
 #endif
 
-UPB_DECLARE_TYPE(upb::pb::TextPrinter, upb_textprinter)
+/* upb_textprinter ************************************************************/
+
+struct upb_textprinter;
+typedef struct upb_textprinter upb_textprinter;
 
 #ifdef __cplusplus
+extern "C" {
+#endif
 
-class upb::pb::TextPrinter {
+/* C API. */
+upb_textprinter *upb_textprinter_create(upb_arena *arena, const upb_handlers *h,
+                                        upb_bytessink output);
+void upb_textprinter_setsingleline(upb_textprinter *p, bool single_line);
+upb_sink upb_textprinter_input(upb_textprinter *p);
+upb_handlercache *upb_textprinter_newcache();
+
+#ifdef __cplusplus
+}  /* extern "C" */
+
+class upb::pb::TextPrinterPtr {
  public:
+  TextPrinterPtr(upb_textprinter* ptr) : ptr_(ptr) {}
+
   /* The given handlers must have come from NewHandlers().  It must outlive the
    * TextPrinter. */
-  static TextPrinter *Create(Environment *env, const upb::Handlers *handlers,
-                             BytesSink *output);
+  static TextPrinterPtr Create(Arena *arena, upb::HandlersPtr *handlers,
+                               BytesSink output) {
+    return TextPrinterPtr(
+        upb_textprinter_create(arena->ptr(), handlers->ptr(), output.sink()));
+  }
 
-  void SetSingleLineMode(bool single_line);
+  void SetSingleLineMode(bool single_line) {
+    upb_textprinter_setsingleline(ptr_, single_line);
+  }
 
-  Sink* input();
+  Sink input() { return upb_textprinter_input(ptr_); }
 
   /* If handler caching becomes a requirement we can add a code cache as in
    * decoder.h */
-  static reffed_ptr<const Handlers> NewHandlers(const MessageDef* md);
+  static HandlerCache NewCache() {
+    return HandlerCache(upb_textprinter_newcache());
+  }
+
+ private:
+  upb_textprinter* ptr_;
 };
 
 #endif
 
-UPB_BEGIN_EXTERN_C
-
-/* C API. */
-upb_textprinter *upb_textprinter_create(upb_env *env, const upb_handlers *h,
-                                        upb_bytessink *output);
-void upb_textprinter_setsingleline(upb_textprinter *p, bool single_line);
-upb_sink *upb_textprinter_input(upb_textprinter *p);
-
-const upb_handlers *upb_textprinter_newhandlers(const upb_msgdef *m,
-                                                const void *owner);
-
-UPB_END_EXTERN_C
-
-#ifdef __cplusplus
-
-namespace upb {
-namespace pb {
-inline TextPrinter *TextPrinter::Create(Environment *env,
-                                        const upb::Handlers *handlers,
-                                        BytesSink *output) {
-  return upb_textprinter_create(env, handlers, output);
-}
-inline void TextPrinter::SetSingleLineMode(bool single_line) {
-  upb_textprinter_setsingleline(this, single_line);
-}
-inline Sink* TextPrinter::input() {
-  return upb_textprinter_input(this);
-}
-inline reffed_ptr<const Handlers> TextPrinter::NewHandlers(
-    const MessageDef *md) {
-  const Handlers* h = upb_textprinter_newhandlers(md, &h);
-  return reffed_ptr<const Handlers>(h, &h);
-}
-}  /* namespace pb */
-}  /* namespace upb */
-
-#endif
-
 #endif  /* UPB_TEXT_H_ */
 /*
 ** upb::json::Parser (upb_json_parser)
@@ -9553,17 +7001,46 @@
 #ifdef __cplusplus
 namespace upb {
 namespace json {
-class Parser;
-class ParserMethod;
+class CodeCache;
+class ParserPtr;
+class ParserMethodPtr;
 }  /* namespace json */
 }  /* namespace upb */
 #endif
 
-UPB_DECLARE_TYPE(upb::json::Parser, upb_json_parser)
-UPB_DECLARE_DERIVED_TYPE(upb::json::ParserMethod, upb::RefCounted,
-                         upb_json_parsermethod, upb_refcounted)
+/* upb_json_parsermethod ******************************************************/
 
-/* upb::json::Parser **********************************************************/
+struct upb_json_parsermethod;
+typedef struct upb_json_parsermethod upb_json_parsermethod;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+const upb_byteshandler* upb_json_parsermethod_inputhandler(
+    const upb_json_parsermethod* m);
+
+#ifdef __cplusplus
+}  /* extern "C" */
+
+class upb::json::ParserMethodPtr {
+ public:
+  ParserMethodPtr() : ptr_(nullptr) {}
+  ParserMethodPtr(const upb_json_parsermethod* ptr) : ptr_(ptr) {}
+
+  const upb_json_parsermethod* ptr() const { return ptr_; }
+
+  const BytesHandler* input_handler() const {
+    return upb_json_parsermethod_inputhandler(ptr());
+  }
+
+ private:
+  const upb_json_parsermethod* ptr_;
+};
+
+#endif  /* __cplusplus */
+
+/* upb_json_parser ************************************************************/
 
 /* Preallocation hint: parser won't allocate more bytes than this when first
  * constructed.  This hint may be an overestimate for some build configurations.
@@ -9571,97 +7048,82 @@
  * it may be an underestimate. */
 #define UPB_JSON_PARSER_SIZE 5712
 
+struct upb_json_parser;
+typedef struct upb_json_parser upb_json_parser;
+
 #ifdef __cplusplus
+extern "C" {
+#endif
+
+upb_json_parser* upb_json_parser_create(upb_arena* a,
+                                        const upb_json_parsermethod* m,
+                                        const upb_symtab* symtab,
+                                        upb_sink output,
+                                        upb_status *status,
+                                        bool ignore_json_unknown);
+upb_bytessink upb_json_parser_input(upb_json_parser* p);
+
+#ifdef __cplusplus
+}  /* extern "C" */
 
 /* Parses an incoming BytesStream, pushing the results to the destination
  * sink. */
-class upb::json::Parser {
+class upb::json::ParserPtr {
  public:
-  static Parser* Create(Environment* env, const ParserMethod* method,
-                        const SymbolTable* symtab,
-                        Sink* output, bool ignore_json_unknown);
+  ParserPtr(upb_json_parser* ptr) : ptr_(ptr) {}
 
-  BytesSink* input();
+  static ParserPtr Create(Arena* arena, ParserMethodPtr method,
+                          SymbolTable* symtab, Sink output, Status* status,
+                          bool ignore_json_unknown) {
+    upb_symtab* symtab_ptr = symtab ? symtab->ptr() : nullptr;
+    return ParserPtr(upb_json_parser_create(
+        arena->ptr(), method.ptr(), symtab_ptr, output.sink(), status->ptr(),
+        ignore_json_unknown));
+  }
+
+  BytesSink input() { return upb_json_parser_input(ptr_); }
 
  private:
-  UPB_DISALLOW_POD_OPS(Parser, upb::json::Parser)
+  upb_json_parser* ptr_;
 };
 
-class upb::json::ParserMethod {
- public:
-  /* Include base methods from upb::ReferenceCounted. */
-  UPB_REFCOUNTED_CPPMETHODS
+#endif  /* __cplusplus */
 
-  /* Returns handlers for parsing according to the specified schema. */
-  static reffed_ptr<const ParserMethod> New(const upb::MessageDef* md);
+/* upb_json_codecache *********************************************************/
 
-  /* The destination handlers that are statically bound to this method.
-   * This method is only capable of outputting to a sink that uses these
-   * handlers. */
-  const Handlers* dest_handlers() const;
+/* Lazily builds and caches decoder methods that will push data to the given
+ * handlers.  The upb_symtab object(s) must outlive this object. */
 
-  /* The input handlers for this decoder method. */
-  const BytesHandler* input_handler() const;
-
- private:
-  UPB_DISALLOW_POD_OPS(ParserMethod, upb::json::ParserMethod)
-};
-
-#endif
-
-UPB_BEGIN_EXTERN_C
-
-upb_json_parser* upb_json_parser_create(upb_env* e,
-                                        const upb_json_parsermethod* m,
-                                        const upb_symtab* symtab,
-                                        upb_sink* output,
-                                        bool ignore_json_unknown);
-upb_bytessink *upb_json_parser_input(upb_json_parser *p);
-
-upb_json_parsermethod* upb_json_parsermethod_new(const upb_msgdef* md,
-                                                 const void* owner);
-const upb_handlers *upb_json_parsermethod_desthandlers(
-    const upb_json_parsermethod *m);
-const upb_byteshandler *upb_json_parsermethod_inputhandler(
-    const upb_json_parsermethod *m);
-
-/* Include refcounted methods like upb_json_parsermethod_ref(). */
-UPB_REFCOUNTED_CMETHODS(upb_json_parsermethod, upb_json_parsermethod_upcast)
-
-UPB_END_EXTERN_C
+struct upb_json_codecache;
+typedef struct upb_json_codecache upb_json_codecache;
 
 #ifdef __cplusplus
-
-namespace upb {
-namespace json {
-inline Parser* Parser::Create(Environment* env, const ParserMethod* method,
-                              const SymbolTable* symtab,
-                              Sink* output, bool ignore_json_unknown) {
-  return upb_json_parser_create(
-      env, method, symtab, output, ignore_json_unknown);
-}
-inline BytesSink* Parser::input() {
-  return upb_json_parser_input(this);
-}
-
-inline const Handlers* ParserMethod::dest_handlers() const {
-  return upb_json_parsermethod_desthandlers(this);
-}
-inline const BytesHandler* ParserMethod::input_handler() const {
-  return upb_json_parsermethod_inputhandler(this);
-}
-/* static */
-inline reffed_ptr<const ParserMethod> ParserMethod::New(
-    const MessageDef* md) {
-  const upb_json_parsermethod *m = upb_json_parsermethod_new(md, &m);
-  return reffed_ptr<const ParserMethod>(m, &m);
-}
-
-}  /* namespace json */
-}  /* namespace upb */
-
+extern "C" {
 #endif
 
+upb_json_codecache *upb_json_codecache_new();
+void upb_json_codecache_free(upb_json_codecache *cache);
+const upb_json_parsermethod* upb_json_codecache_get(upb_json_codecache* cache,
+                                                    const upb_msgdef* md);
+
+#ifdef __cplusplus
+}  /* extern "C" */
+
+class upb::json::CodeCache {
+ public:
+  CodeCache() : ptr_(upb_json_codecache_new(), upb_json_codecache_free) {}
+
+  /* Returns a DecoderMethod that can push data to the given handlers.
+   * If a suitable method already exists, it will be returned from the cache. */
+  ParserMethodPtr Get(MessageDefPtr md) {
+    return upb_json_codecache_get(ptr_.get(), md.ptr());
+  }
+
+ private:
+  std::unique_ptr<upb_json_codecache, decltype(&upb_json_codecache_free)> ptr_;
+};
+
+#endif
 
 #endif  /* UPB_JSON_PARSER_H_ */
 /*
@@ -9677,75 +7139,62 @@
 #ifdef __cplusplus
 namespace upb {
 namespace json {
-class Printer;
+class PrinterPtr;
 }  /* namespace json */
 }  /* namespace upb */
 #endif
 
-UPB_DECLARE_TYPE(upb::json::Printer, upb_json_printer)
-
-
-/* upb::json::Printer *********************************************************/
+/* upb_json_printer ***********************************************************/
 
 #define UPB_JSON_PRINTER_SIZE 192
 
+struct upb_json_printer;
+typedef struct upb_json_printer upb_json_printer;
+
 #ifdef __cplusplus
-
-/* Prints an incoming stream of data to a BytesSink in JSON format. */
-class upb::json::Printer {
- public:
-  static Printer* Create(Environment* env, const upb::Handlers* handlers,
-                         BytesSink* output);
-
-  /* The input to the printer. */
-  Sink* input();
-
-  /* Returns handlers for printing according to the specified schema.
-   * If preserve_proto_fieldnames is true, the output JSON will use the
-   * original .proto field names (ie. {"my_field":3}) instead of using
-   * camelCased names, which is the default: (eg. {"myField":3}). */
-  static reffed_ptr<const Handlers> NewHandlers(const upb::MessageDef* md,
-                                                bool preserve_proto_fieldnames);
-
-  static const size_t kSize = UPB_JSON_PRINTER_SIZE;
-
- private:
-  UPB_DISALLOW_POD_OPS(Printer, upb::json::Printer)
-};
-
+extern "C" {
 #endif
 
-UPB_BEGIN_EXTERN_C
-
 /* Native C API. */
-upb_json_printer *upb_json_printer_create(upb_env *e, const upb_handlers *h,
-                                          upb_bytessink *output);
-upb_sink *upb_json_printer_input(upb_json_printer *p);
+upb_json_printer *upb_json_printer_create(upb_arena *a, const upb_handlers *h,
+                                          upb_bytessink output);
+upb_sink upb_json_printer_input(upb_json_printer *p);
 const upb_handlers *upb_json_printer_newhandlers(const upb_msgdef *md,
                                                  bool preserve_fieldnames,
                                                  const void *owner);
 
-UPB_END_EXTERN_C
+/* Lazily builds and caches handlers that will push encoded data to a bytessink.
+ * Any msgdef objects used with this object must outlive it. */
+upb_handlercache *upb_json_printer_newcache(bool preserve_proto_fieldnames);
 
 #ifdef __cplusplus
+}  /* extern "C" */
 
-namespace upb {
-namespace json {
-inline Printer* Printer::Create(Environment* env, const upb::Handlers* handlers,
-                                BytesSink* output) {
-  return upb_json_printer_create(env, handlers, output);
-}
-inline Sink* Printer::input() { return upb_json_printer_input(this); }
-inline reffed_ptr<const Handlers> Printer::NewHandlers(
-    const upb::MessageDef *md, bool preserve_proto_fieldnames) {
-  const Handlers* h = upb_json_printer_newhandlers(
-      md, preserve_proto_fieldnames, &h);
-  return reffed_ptr<const Handlers>(h, &h);
-}
-}  /* namespace json */
-}  /* namespace upb */
+/* Prints an incoming stream of data to a BytesSink in JSON format. */
+class upb::json::PrinterPtr {
+ public:
+  PrinterPtr(upb_json_printer* ptr) : ptr_(ptr) {}
 
-#endif
+  static PrinterPtr Create(Arena *arena, const upb::Handlers *handlers,
+                           BytesSink output) {
+    return PrinterPtr(
+        upb_json_printer_create(arena->ptr(), handlers, output.sink()));
+  }
+
+  /* The input to the printer. */
+  Sink input() { return upb_json_printer_input(ptr_); }
+
+  static const size_t kSize = UPB_JSON_PRINTER_SIZE;
+
+  static HandlerCache NewCache(bool preserve_proto_fieldnames) {
+    return upb_json_printer_newcache(preserve_proto_fieldnames);
+  }
+
+ private:
+  upb_json_printer* ptr_;
+};
+
+#endif  /* __cplusplus */
 
 #endif  /* UPB_JSON_TYPED_PRINTER_H_ */
 
diff --git a/ruby/lib/google/protobuf.rb b/ruby/lib/google/protobuf.rb
index 464982e..3aef079 100644
--- a/ruby/lib/google/protobuf.rb
+++ b/ruby/lib/google/protobuf.rb
@@ -50,6 +50,72 @@
   rescue LoadError
     require 'google/protobuf_c'
   end
+
+  module Google
+    module Protobuf
+      module Internal
+        def self.infer_package(names)
+          # Package is longest common prefix ending in '.', if any.
+          min, max = names.minmax
+          last_common_dot = nil
+          min.size.times { |i|
+            if min[i] != max[i] then break end
+            if min[i] == ?. then last_common_dot = i end
+          }
+          if last_common_dot
+            return min.slice(0, last_common_dot)
+          end
+        end
+
+        class NestingBuilder
+          def initialize(msg_names, enum_names)
+            @to_pos = {nil=>nil}
+            @msg_children = Hash.new { |hash, key| hash[key] = [] }
+            @enum_children = Hash.new { |hash, key| hash[key] = [] }
+
+            msg_names.each_with_index { |name, idx| @to_pos[name] = idx }
+            enum_names.each_with_index { |name, idx| @to_pos[name] = idx }
+
+            msg_names.each { |name| @msg_children[parent(name)] << name }
+            enum_names.each { |name| @enum_children[parent(name)] << name }
+          end
+
+          def build(package)
+            return build_msg(package)
+          end
+
+          private
+          def build_msg(msg)
+            return {
+              :pos => @to_pos[msg],
+              :msgs => @msg_children[msg].map { |child| build_msg(child) },
+              :enums => @enum_children[msg].map { |child| @to_pos[child] },
+            }
+          end
+
+          private
+          def parent(name)
+            idx = name.rindex(?.)
+            if idx
+              return name.slice(0, idx)
+            else
+              return nil
+            end
+          end
+        end
+
+        def self.fixup_descriptor(package, msg_names, enum_names)
+          if package.nil?
+            package = self.infer_package(msg_names + enum_names)
+          end
+
+          nesting = NestingBuilder.new(msg_names, enum_names).build(package)
+
+          return package, nesting
+        end
+      end
+    end
+  end
 end
 
 require 'google/protobuf/repeated_field'
diff --git a/ruby/tests/basic.rb b/ruby/tests/basic.rb
index db97614..4c8b2a5 100644
--- a/ruby/tests/basic.rb
+++ b/ruby/tests/basic.rb
@@ -17,7 +17,6 @@
     add_message "BadFieldNames" do
       optional :dup, :int32, 1
       optional :class, :int32, 2
-      optional :"a.b", :int32, 3
     end
   end
 
@@ -351,11 +350,6 @@
       assert nil != file_descriptor
       assert_equal "tests/basic_test.proto", file_descriptor.name
       assert_equal :proto3, file_descriptor.syntax
-
-      file_descriptor = BadFieldNames.descriptor.file_descriptor
-      assert nil != file_descriptor
-      assert_equal nil, file_descriptor.name
-      assert_equal :proto3, file_descriptor.syntax
     end
 
     def test_map_freeze
diff --git a/ruby/tests/basic_proto2.rb b/ruby/tests/basic_proto2.rb
index 53d6a70..4c7ddd5 100644
--- a/ruby/tests/basic_proto2.rb
+++ b/ruby/tests/basic_proto2.rb
@@ -18,7 +18,6 @@
       add_message "BadFieldNames" do
         optional :dup, :int32, 1
         optional :class, :int32, 2
-        optional :"a.b", :int32, 3
       end
     end
   end
diff --git a/ruby/tests/common_tests.rb b/ruby/tests/common_tests.rb
index 638ad76..8b790d5 100644
--- a/ruby/tests/common_tests.rb
+++ b/ruby/tests/common_tests.rb
@@ -807,7 +807,7 @@
                                                         proto_module::TestMessage2.new(:foo => 2)])
     data = proto_module::TestMessage.encode m
     m2 = proto_module::TestMessage.decode data
-    assert m == m2
+    assert_equal m, m2
 
     data = Google::Protobuf.encode m
     m2 = Google::Protobuf.decode(proto_module::TestMessage, data)
@@ -902,8 +902,6 @@
     assert m['class'] == 2
     m['dup'] = 3
     assert m['dup'] == 3
-    m['a.b'] = 4
-    assert m['a.b'] == 4
   end
 
   def test_int_ranges
@@ -1084,9 +1082,7 @@
 
     json_text = proto_module::TestMessage.encode_json(m)
     m2 = proto_module::TestMessage.decode_json(json_text)
-    puts m.inspect
-    puts m2.inspect
-    assert m == m2
+    assert_equal m, m2
 
     # Crash case from GitHub issue 283.
     bar = proto_module::Bar.new(msg: "bar")
@@ -1132,7 +1128,7 @@
 
     actual = proto_module::TestMessage.encode_json(m, :emit_defaults => true)
 
-    assert JSON.parse(actual, :symbolize_names => true) == expected
+    assert_equal expected, JSON.parse(actual, :symbolize_names => true)
   end
 
   def test_json_emit_defaults_submsg
@@ -1167,7 +1163,7 @@
 
     actual = proto_module::TestMessage.encode_json(m, :emit_defaults => true)
 
-    assert JSON.parse(actual, :symbolize_names => true) == expected
+    assert_equal expected, JSON.parse(actual, :symbolize_names => true)
   end
 
   def test_json_emit_defaults_repeated_submsg
@@ -1201,7 +1197,7 @@
 
     actual = proto_module::TestMessage.encode_json(m, :emit_defaults => true)
 
-    assert JSON.parse(actual, :symbolize_names => true) == expected
+    assert_equal expected, JSON.parse(actual, :symbolize_names => true)
   end
 
   def value_from_ruby(value)
diff --git a/ruby/tests/type_errors.rb b/ruby/tests/type_errors.rb
index 76c591c..6e42308 100644
--- a/ruby/tests/type_errors.rb
+++ b/ruby/tests/type_errors.rb
@@ -10,11 +10,11 @@
 class TestTypeErrors < Test::Unit::TestCase
   def test_bad_string
     check_error Google::Protobuf::TypeError,
-                "Invalid argument for string field 'optional_string' (given Integer)." do
+                "Invalid argument for string field 'optional_string' (given Fixnum)." do
       A::B::C::TestMessage.new(optional_string: 4)
     end
     check_error Google::Protobuf::TypeError,
-                "Invalid argument for string field 'oneof_string' (given Integer)." do
+                "Invalid argument for string field 'oneof_string' (given Fixnum)." do
       A::B::C::TestMessage.new(oneof_string: 4)
     end
     check_error ArgumentError,
@@ -151,7 +151,7 @@
 
   def test_bad_msg
     check_error Google::Protobuf::TypeError,
-                "Invalid type Integer to assign to submessage field 'optional_msg'." do
+                "Invalid type Fixnum to assign to submessage field 'optional_msg'." do
       A::B::C::TestMessage.new(optional_msg: 2)
     end
     check_error Google::Protobuf::TypeError,