AAPT2: Produce Conditional Proguard Keep Rules
Add the option to produce keep rules that conditional keep based on
usage of R identifiers. This allows Proguard to potentially shrink more
code if resources are not used.
Currently only produces conditional rules for classes referenced in
layout resources because they are the most common and has the easiest
transitive usage chain to analyze.
Bug: 63628451
Test: make aapt2_tests and manual testing
Change-Id: I6c1af7affd64af40c80e004d8506a9463444b2c3
diff --git a/tools/aapt2/java/ProguardRules.cpp b/tools/aapt2/java/ProguardRules.cpp
index 10c4610..b9ae654 100644
--- a/tools/aapt2/java/ProguardRules.cpp
+++ b/tools/aapt2/java/ProguardRules.cpp
@@ -21,6 +21,10 @@
#include "android-base/macros.h"
+#include "JavaClassGenerator.h"
+#include "ResourceUtils.h"
+#include "ValueVisitor.h"
+#include "androidfw/StringPiece.h"
#include "util/Util.h"
#include "xml/XmlDom.h"
@@ -31,7 +35,7 @@
public:
using xml::Visitor::Visit;
- BaseVisitor(const Source& source, KeepSet* keep_set) : source_(source), keep_set_(keep_set) {
+ BaseVisitor(const ResourceFile& file, KeepSet* keep_set) : file_(file), keep_set_(keep_set) {
}
void Visit(xml::Element* node) override {
@@ -52,27 +56,47 @@
for (const auto& child : node->children) {
child->Accept(this);
}
+
+ for (const auto& attr : node->attributes) {
+ if (attr.compiled_value) {
+ auto ref = ValueCast<Reference>(attr.compiled_value.get());
+ if (ref) {
+ AddReference(node->line_number, ref);
+ }
+ }
+ }
}
protected:
- void AddClass(size_t line_number, const std::string& class_name) {
- keep_set_->AddClass(Source(source_.path, line_number), class_name);
+ ResourceFile file_;
+ KeepSet* keep_set_;
+
+ virtual void AddClass(size_t line_number, const std::string& class_name) {
+ keep_set_->AddConditionalClass({file_.name, file_.source.WithLine(line_number)}, class_name);
}
void AddMethod(size_t line_number, const std::string& method_name) {
- keep_set_->AddMethod(Source(source_.path, line_number), method_name);
+ keep_set_->AddMethod({file_.name, file_.source.WithLine(line_number)}, method_name);
+ }
+
+ void AddReference(size_t line_number, Reference* ref) {
+ if (ref && ref->name) {
+ ResourceName ref_name = ref->name.value();
+ if (ref_name.package.empty()) {
+ ref_name = ResourceName(file_.name.package, ref_name.type, ref_name.entry);
+ }
+ keep_set_->AddReference({file_.name, file_.source.WithLine(line_number)}, ref_name);
+ }
}
private:
DISALLOW_COPY_AND_ASSIGN(BaseVisitor);
- Source source_;
- KeepSet* keep_set_;
};
class LayoutVisitor : public BaseVisitor {
public:
- LayoutVisitor(const Source& source, KeepSet* keep_set) : BaseVisitor(source, keep_set) {
+ LayoutVisitor(const ResourceFile& file, KeepSet* keep_set) : BaseVisitor(file, keep_set) {
}
void Visit(xml::Element* node) override {
@@ -110,7 +134,7 @@
class MenuVisitor : public BaseVisitor {
public:
- MenuVisitor(const Source& source, KeepSet* keep_set) : BaseVisitor(source, keep_set) {
+ MenuVisitor(const ResourceFile& file, KeepSet* keep_set) : BaseVisitor(file, keep_set) {
}
void Visit(xml::Element* node) override {
@@ -136,7 +160,7 @@
class XmlResourceVisitor : public BaseVisitor {
public:
- XmlResourceVisitor(const Source& source, KeepSet* keep_set) : BaseVisitor(source, keep_set) {
+ XmlResourceVisitor(const ResourceFile& file, KeepSet* keep_set) : BaseVisitor(file, keep_set) {
}
void Visit(xml::Element* node) override {
@@ -163,7 +187,7 @@
class TransitionVisitor : public BaseVisitor {
public:
- TransitionVisitor(const Source& source, KeepSet* keep_set) : BaseVisitor(source, keep_set) {
+ TransitionVisitor(const ResourceFile& file, KeepSet* keep_set) : BaseVisitor(file, keep_set) {
}
void Visit(xml::Element* node) override {
@@ -185,8 +209,9 @@
class ManifestVisitor : public BaseVisitor {
public:
- ManifestVisitor(const Source& source, KeepSet* keep_set, bool main_dex_only)
- : BaseVisitor(source, keep_set), main_dex_only_(main_dex_only) {}
+ ManifestVisitor(const ResourceFile& file, KeepSet* keep_set, bool main_dex_only)
+ : BaseVisitor(file, keep_set), main_dex_only_(main_dex_only) {
+ }
void Visit(xml::Element* node) override {
if (node->namespace_uri.empty()) {
@@ -241,6 +266,10 @@
BaseVisitor::Visit(node);
}
+ virtual void AddClass(size_t line_number, const std::string& class_name) override {
+ keep_set_->AddManifestClass({file_.name, file_.source.WithLine(line_number)}, class_name);
+ }
+
private:
DISALLOW_COPY_AND_ASSIGN(ManifestVisitor);
@@ -249,9 +278,8 @@
std::string default_process_;
};
-bool CollectProguardRulesForManifest(const Source& source, xml::XmlResource* res, KeepSet* keep_set,
- bool main_dex_only) {
- ManifestVisitor visitor(source, keep_set, main_dex_only);
+bool CollectProguardRulesForManifest(xml::XmlResource* res, KeepSet* keep_set, bool main_dex_only) {
+ ManifestVisitor visitor(res->file, keep_set, main_dex_only);
if (res->root) {
res->root->Accept(&visitor);
return true;
@@ -259,58 +287,150 @@
return false;
}
-bool CollectProguardRules(const Source& source, xml::XmlResource* res, KeepSet* keep_set) {
+bool CollectProguardRules(xml::XmlResource* res, KeepSet* keep_set) {
if (!res->root) {
return false;
}
switch (res->file.name.type) {
case ResourceType::kLayout: {
- LayoutVisitor visitor(source, keep_set);
+ LayoutVisitor visitor(res->file, keep_set);
res->root->Accept(&visitor);
break;
}
case ResourceType::kXml: {
- XmlResourceVisitor visitor(source, keep_set);
+ XmlResourceVisitor visitor(res->file, keep_set);
res->root->Accept(&visitor);
break;
}
case ResourceType::kTransition: {
- TransitionVisitor visitor(source, keep_set);
+ TransitionVisitor visitor(res->file, keep_set);
res->root->Accept(&visitor);
break;
}
case ResourceType::kMenu: {
- MenuVisitor visitor(source, keep_set);
+ MenuVisitor visitor(res->file, keep_set);
res->root->Accept(&visitor);
break;
}
- default:
+ default: {
+ BaseVisitor visitor(res->file, keep_set);
+ res->root->Accept(&visitor);
break;
+ }
}
return true;
}
bool WriteKeepSet(std::ostream* out, const KeepSet& keep_set) {
- for (const auto& entry : keep_set.keep_set_) {
- for (const Source& source : entry.second) {
- *out << "# Referenced at " << source << "\n";
+ for (const auto& entry : keep_set.manifest_class_set_) {
+ for (const UsageLocation& location : entry.second) {
+ *out << "# Referenced at " << location.source << "\n";
}
*out << "-keep class " << entry.first << " { <init>(...); }\n" << std::endl;
}
- for (const auto& entry : keep_set.keep_method_set_) {
- for (const Source& source : entry.second) {
- *out << "# Referenced at " << source << "\n";
+ for (const auto& entry : keep_set.conditional_class_set_) {
+ std::set<UsageLocation> locations;
+ bool can_be_conditional = true;
+ for (const UsageLocation& location : entry.second) {
+ can_be_conditional &= CollectLocations(location, keep_set, &locations);
+ }
+
+ for (const UsageLocation& location : entry.second) {
+ *out << "# Referenced at " << location.source << "\n";
+ }
+ if (keep_set.conditional_keep_rules_ && can_be_conditional) {
+ *out << "-keep class " << entry.first << " {\n ifused class **.R$layout {\n";
+ for (const UsageLocation& location : locations) {
+ auto transformed_name = JavaClassGenerator::TransformToFieldName(location.name.entry);
+ *out << " int " << transformed_name << ";\n";
+ }
+ *out << " };\n <init>(...);\n}\n" << std::endl;
+ } else {
+ *out << "-keep class " << entry.first << " { <init>(...); }\n" << std::endl;
+ }
+ }
+
+ for (const auto& entry : keep_set.method_set_) {
+ for (const UsageLocation& location : entry.second) {
+ *out << "# Referenced at " << location.source << "\n";
}
*out << "-keepclassmembers class * { *** " << entry.first << "(...); }\n" << std::endl;
}
return true;
}
+bool CollectLocations(const UsageLocation& location, const KeepSet& keep_set,
+ std::set<UsageLocation>* locations) {
+ locations->insert(location);
+
+ // TODO: allow for more reference types if we can determine its safe.
+ if (location.name.type != ResourceType::kLayout) {
+ return false;
+ }
+
+ for (const auto& entry : keep_set.reference_set_) {
+ if (entry.first == location.name) {
+ for (auto& refLocation : entry.second) {
+ // Don't get stuck in loops
+ if (locations->find(refLocation) != locations->end()) {
+ return false;
+ }
+ if (!CollectLocations(refLocation, keep_set, locations)) {
+ return false;
+ }
+ }
+ }
+ }
+
+ return true;
+}
+
+class ReferenceVisitor : public ValueVisitor {
+ public:
+ using ValueVisitor::Visit;
+
+ ReferenceVisitor(aapt::IAaptContext* context, ResourceName from, KeepSet* keep_set)
+ : context_(context), from_(from), keep_set_(keep_set) {
+ }
+
+ void Visit(Reference* reference) override {
+ if (reference->name) {
+ ResourceName reference_name = reference->name.value();
+ if (reference_name.package.empty()) {
+ reference_name = ResourceName(context_->GetCompilationPackage(), reference_name.type,
+ reference_name.entry);
+ }
+ keep_set_->AddReference({from_, reference->GetSource()}, reference_name);
+ }
+ }
+
+ private:
+ aapt::IAaptContext* context_;
+ ResourceName from_;
+ KeepSet* keep_set_;
+};
+
+bool CollectResourceReferences(aapt::IAaptContext* context, ResourceTable* table,
+ KeepSet* keep_set) {
+ for (auto& pkg : table->packages) {
+ for (auto& type : pkg->types) {
+ for (auto& entry : type->entries) {
+ for (auto& config_value : entry->values) {
+ ResourceName from(pkg->name, type->type, entry->name);
+ ReferenceVisitor visitor(context, from, keep_set);
+ config_value->value->Accept(&visitor);
+ }
+ }
+ }
+ }
+ return true;
+}
+
} // namespace proguard
} // namespace aapt
