src/hotspot/share/runtime/interfaceSupport.inline.hpp - toolchain/jdk/jdk21 - Git at Google

 /*
  * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */

 #ifndef SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP
 #define SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP

 // No interfaceSupport.hpp

 #include "gc/shared/gc_globals.hpp"
 #include "runtime/globals.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/javaThread.inline.hpp"
 #include "runtime/mutexLocker.hpp"
 #include "runtime/orderAccess.hpp"
 #include "runtime/os.hpp"
 #include "runtime/safepointMechanism.inline.hpp"
 #include "runtime/safepointVerifiers.hpp"
 #include "runtime/threadWXSetters.inline.hpp"
 #include "runtime/vmOperations.hpp"
 #include "utilities/globalDefinitions.hpp"
 #include "utilities/macros.hpp"
 #include "utilities/preserveException.hpp"

 // Wrapper for all entry points to the virtual machine.

 // InterfaceSupport provides functionality used by the VM_LEAF_BASE and
 // VM_ENTRY_BASE macros. These macros are used to guard entry points into
 // the VM and perform checks upon leave of the VM.


 class InterfaceSupport: AllStatic {
 # ifdef ASSERT
  public:
   static unsigned int _scavenge_alot_counter;
   static unsigned int _fullgc_alot_counter;
   static intx _fullgc_alot_invocation;

   // Helper methods used to implement +ScavengeALot and +FullGCALot
   static void check_gc_alot() { if (ScavengeALot || FullGCALot) gc_alot(); }
   static void gc_alot();

   static void walk_stack_from(vframe* start_vf);
   static void walk_stack();

   static void zombieAll();
   static void deoptimizeAll();
   static void verify_stack();
   static void verify_last_frame();
 # endif
 };


 // Basic class for all thread transition classes.

 class ThreadStateTransition : public StackObj {
  protected:
   JavaThread* _thread;

  public:
   ThreadStateTransition(JavaThread *thread) : _thread(thread) {
     assert(thread != nullptr, "must be active Java thread");
     assert(thread == Thread::current(), "must be current thread");
   }

   static inline void transition_from_java(JavaThread *thread, JavaThreadState to) {
     assert(thread->thread_state() == _thread_in_Java, "coming from wrong thread state");
     assert(to == _thread_in_vm || to == _thread_in_native, "invalid transition");
     thread->set_thread_state(to);
   }

   // We never install asynchronous exceptions when coming (back) in to the runtime
   // from native code because the runtime is not set up to handle exceptions floating
   // around at arbitrary points.
   static inline void transition_from_native(JavaThread *thread, JavaThreadState to, bool check_asyncs = true) {
     assert(thread->thread_state() == _thread_in_native, "coming from wrong thread state");
     assert(to == _thread_in_vm || to == _thread_in_Java, "invalid transition");
     assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native transition");

     if (!UseSystemMemoryBarrier) {
       thread->set_thread_state_fence(_thread_in_vm);
     } else {
       thread->set_thread_state(_thread_in_vm);
     }
     SafepointMechanism::process_if_requested_with_exit_check(thread, to != _thread_in_Java ? false : check_asyncs);
     thread->set_thread_state(to);
   }

   static inline void transition_from_vm(JavaThread *thread, JavaThreadState to, bool check_asyncs = true) {
     assert(thread->thread_state() == _thread_in_vm, "coming from wrong thread state");
     if (to == _thread_in_Java) {
       SafepointMechanism::process_if_requested_with_exit_check(thread, check_asyncs);
       thread->set_thread_state(to);
     } else {
       assert(to == _thread_in_native || to == _thread_blocked, "invalid transition");
       // Check NoSafepointVerifier. This also clears unhandled oops if CheckUnhandledOops is used.
       thread->check_possible_safepoint();

       // Once we are in native/blocked vm expects stack to be walkable
       thread->frame_anchor()->make_walkable();
       OrderAccess::storestore(); // Keep thread_state change and make_walkable() separate.
       thread->set_thread_state(to);
     }
   }
 };

 class ThreadInVMfromJava : public ThreadStateTransition {
   bool _check_asyncs;
  public:
   ThreadInVMfromJava(JavaThread* thread, bool check_asyncs = true) : ThreadStateTransition(thread), _check_asyncs(check_asyncs) {
     transition_from_java(thread, _thread_in_vm);
   }
   ~ThreadInVMfromJava()  {
     if (_thread->stack_overflow_state()->stack_yellow_reserved_zone_disabled()) {
       _thread->stack_overflow_state()->enable_stack_yellow_reserved_zone();
     }
     // We prevent asynchronous exceptions from being installed on return to Java in situations
     // where we can't tolerate them. See bugs: 4324348, 4854693, 4998314, 5040492, 5050705.
     transition_from_vm(_thread, _thread_in_Java, _check_asyncs);
   }
 };


 class ThreadInVMfromUnknown {
   JavaThread* _thread;
  public:
   ThreadInVMfromUnknown() : _thread(nullptr) {
     Thread* t = Thread::current();
     if (t->is_Java_thread()) {
       JavaThread* t2 = JavaThread::cast(t);
       if (t2->thread_state() == _thread_in_native) {
         _thread = t2;
         ThreadStateTransition::transition_from_native(t2, _thread_in_vm);
         // Used to have a HandleMarkCleaner but that is dangerous as
         // it could free a handle in our (indirect, nested) caller.
         // We expect any handles will be short lived and figure we
         // don't need an actual HandleMark.
       }
     }
   }
   ~ThreadInVMfromUnknown()  {
     if (_thread) {
       ThreadStateTransition::transition_from_vm(_thread, _thread_in_native);
     }
   }
 };


 class ThreadInVMfromNative : public ThreadStateTransition {
   ResetNoHandleMark __rnhm;
  public:
   ThreadInVMfromNative(JavaThread* thread) : ThreadStateTransition(thread) {
     transition_from_native(thread, _thread_in_vm);
   }
   ~ThreadInVMfromNative() {
     // We cannot assert !_thread->owns_locks() since we have valid cases where
     // we call known native code using this wrapper holding locks.
     transition_from_vm(_thread, _thread_in_native);
   }
 };


 class ThreadToNativeFromVM : public ThreadStateTransition {
  public:
   ThreadToNativeFromVM(JavaThread *thread) : ThreadStateTransition(thread) {
     assert(!thread->owns_locks(), "must release all locks when leaving VM");
     transition_from_vm(thread, _thread_in_native);
   }
   ~ThreadToNativeFromVM() {
     transition_from_native(_thread, _thread_in_vm);
     assert(!_thread->is_pending_jni_exception_check(), "Pending JNI Exception Check");
     // We don't need to clear_walkable because it will happen automagically when we return to java
   }
 };

 // Perform a transition to _thread_blocked and take a call-back to be executed before
 // SafepointMechanism::process_if_requested when returning to the VM. This allows us
 // to perform an "undo" action if we might block processing a safepoint/handshake operation
 // (such as thread suspension).
 template <typename PRE_PROC = void(JavaThread*)>
 class ThreadBlockInVMPreprocess : public ThreadStateTransition {
  private:
   PRE_PROC& _pr;
   bool _allow_suspend;
  public:
   ThreadBlockInVMPreprocess(JavaThread* thread, PRE_PROC& pr, bool allow_suspend = false)
     : ThreadStateTransition(thread), _pr(pr), _allow_suspend(allow_suspend) {
     transition_from_vm(thread, _thread_blocked);
   }
   ~ThreadBlockInVMPreprocess() {
     assert(_thread->thread_state() == _thread_blocked, "coming from wrong thread state");
     // Change back to _thread_in_vm and ensure it is seen by the VM thread.
     _thread->set_thread_state_fence(_thread_in_vm);

     if (SafepointMechanism::should_process(_thread, _allow_suspend)) {
       _pr(_thread);
       SafepointMechanism::process_if_requested(_thread, _allow_suspend, false /* check_async_exception */);
     }
   }
 };

 class ThreadBlockInVM  : public ThreadBlockInVMPreprocess<> {
  public:
   ThreadBlockInVM(JavaThread* thread, bool allow_suspend = false)
     : ThreadBlockInVMPreprocess(thread, emptyOp, allow_suspend) {}
  private:
   static void emptyOp(JavaThread* current) {}
 };


 // Debug class instantiated in JRT_ENTRY macro.
 // Can be used to verify properties on enter/exit of the VM.

 #ifdef ASSERT
 class VMEntryWrapper {
  public:
   VMEntryWrapper();
   ~VMEntryWrapper();
 };


 class VMNativeEntryWrapper {
  public:
   VMNativeEntryWrapper();
   ~VMNativeEntryWrapper();
 };

 #endif // ASSERT

 // LEAF routines do not lock, GC or throw exceptions

 // On macos/aarch64 we need to maintain the W^X state of the thread.  So we
 // take WXWrite on the enter to VM from the "outside" world, so the rest of JVM
 // code can assume writing (but not executing) codecache is always possible
 // without preliminary actions.
 // JavaThread state should be changed only after taking WXWrite. The state
 // change may trigger a safepoint, that would need WXWrite to do bookkeeping
 // in the codecache.

 #define VM_LEAF_BASE(result_type, header)                            \
   debug_only(NoHandleMark __hm;)                                     \
   os::verify_stack_alignment();                                      \
   /* begin of body */

 #define VM_ENTRY_BASE_FROM_LEAF(result_type, header, thread)         \
   debug_only(ResetNoHandleMark __rnhm;)                              \
   HandleMarkCleaner __hm(thread);                                    \
   JavaThread* THREAD = thread; /* For exception macros. */           \
   os::verify_stack_alignment();                                      \
   /* begin of body */


 // ENTRY routines may lock, GC and throw exceptions

 #define VM_ENTRY_BASE(result_type, header, thread)                   \
   HandleMarkCleaner __hm(thread);                                    \
   JavaThread* THREAD = thread; /* For exception macros. */           \
   os::verify_stack_alignment();                                      \
   /* begin of body */


 #define JRT_ENTRY(result_type, header)                               \
   result_type header {                                               \
     assert(current == JavaThread::current(), "Must be");             \
     MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, current));       \
     ThreadInVMfromJava __tiv(current);                               \
     VM_ENTRY_BASE(result_type, header, current)                      \
     debug_only(VMEntryWrapper __vew;)

 // JRT_LEAF currently can be called from either _thread_in_Java or
 // _thread_in_native mode.
 //
 // JRT_LEAF rules:
 // A JRT_LEAF method may not interfere with safepointing by
 //   1) acquiring or blocking on a Mutex or JavaLock - checked
 //   2) allocating heap memory - checked
 //   3) executing a VM operation - checked
 //   4) executing a system call (including malloc) that could block or grab a lock
 //   5) invoking GC
 //   6) reaching a safepoint
 //   7) running too long
 // Nor may any method it calls.

 #define JRT_LEAF(result_type, header)                                \
   result_type header {                                               \
   VM_LEAF_BASE(result_type, header)                                  \
   debug_only(NoSafepointVerifier __nsv;)


 #define JRT_ENTRY_NO_ASYNC(result_type, header)                      \
   result_type header {                                               \
     assert(current == JavaThread::current(), "Must be");             \
     MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, current));       \
     ThreadInVMfromJava __tiv(current, false /* check asyncs */);     \
     VM_ENTRY_BASE(result_type, header, current)                      \
     debug_only(VMEntryWrapper __vew;)

 // Same as JRT Entry but allows for return value after the safepoint
 // to get back into Java from the VM
 #define JRT_BLOCK_ENTRY(result_type, header)                         \
   result_type header {                                               \
     assert(current == JavaThread::current(), "Must be");             \
     MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, current));       \
     HandleMarkCleaner __hm(current);

 #define JRT_BLOCK                                                    \
     {                                                                \
     assert(current == JavaThread::current(), "Must be");             \
     ThreadInVMfromJava __tiv(current);                               \
     JavaThread* THREAD = current; /* For exception macros. */        \
     debug_only(VMEntryWrapper __vew;)

 #define JRT_BLOCK_NO_ASYNC                                           \
     {                                                                \
     assert(current == JavaThread::current(), "Must be");             \
     ThreadInVMfromJava __tiv(current, false /* check asyncs */);     \
     JavaThread* THREAD = current; /* For exception macros. */        \
     debug_only(VMEntryWrapper __vew;)

 #define JRT_BLOCK_END }

 #define JRT_END }

 // Definitions for JNI
 //
 // As the JNIEnv can be passed from external native code we validate
 // it in debug builds, primarily for our own testing. In general JNI
 // does not attempt to detect programming errors and a bad JNIEnv may
 // not even be readable.

 #define JNI_ENTRY(result_type, header)                               \
     JNI_ENTRY_NO_PRESERVE(result_type, header)                       \
     WeakPreserveExceptionMark __wem(thread);

 #define JNI_ENTRY_NO_PRESERVE(result_type, header)                   \
 extern "C" {                                                         \
   result_type JNICALL header {                                       \
     JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
     assert(thread == Thread::current(), "JNIEnv is only valid in same thread"); \
     MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, thread));        \
     ThreadInVMfromNative __tiv(thread);                              \
     debug_only(VMNativeEntryWrapper __vew;)                          \
     VM_ENTRY_BASE(result_type, header, thread)


 #define JNI_LEAF(result_type, header)                                \
 extern "C" {                                                         \
   result_type JNICALL header {                                       \
     JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
     assert(thread == Thread::current(), "JNIEnv is only valid in same thread"); \
     VM_LEAF_BASE(result_type, header)


 // Close the routine and the extern "C"
 #define JNI_END } }


 // Definitions for JVM

 #define JVM_ENTRY(result_type, header)                               \
 extern "C" {                                                         \
   result_type JNICALL header {                                       \
     JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
     MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, thread));        \
     ThreadInVMfromNative __tiv(thread);                              \
     debug_only(VMNativeEntryWrapper __vew;)                          \
     VM_ENTRY_BASE(result_type, header, thread)


 #define JVM_ENTRY_NO_ENV(result_type, header)                        \
 extern "C" {                                                         \
   result_type JNICALL header {                                       \
     JavaThread* thread = JavaThread::current();                      \
     MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, thread));        \
     ThreadInVMfromNative __tiv(thread);                              \
     debug_only(VMNativeEntryWrapper __vew;)                          \
     VM_ENTRY_BASE(result_type, header, thread)


 #define JVM_LEAF(result_type, header)                                \
 extern "C" {                                                         \
   result_type JNICALL header {                                       \
     VM_Exit::block_if_vm_exited();                                   \
     VM_LEAF_BASE(result_type, header)


 #define JVM_ENTRY_FROM_LEAF(env, result_type, header)                \
   { {                                                                \
     JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
     MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, thread));        \
     ThreadInVMfromNative __tiv(thread);                              \
     debug_only(VMNativeEntryWrapper __vew;)                          \
     VM_ENTRY_BASE_FROM_LEAF(result_type, header, thread)


 #define JVM_END } }

 #endif // SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP
	/*
	* Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
	* Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*
	*/

	#ifndef SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP
	#define SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP

	// No interfaceSupport.hpp

	#include "gc/shared/gc_globals.hpp"
	#include "runtime/globals.hpp"
	#include "runtime/handles.inline.hpp"
	#include "runtime/javaThread.inline.hpp"
	#include "runtime/mutexLocker.hpp"
	#include "runtime/orderAccess.hpp"
	#include "runtime/os.hpp"
	#include "runtime/safepointMechanism.inline.hpp"
	#include "runtime/safepointVerifiers.hpp"
	#include "runtime/threadWXSetters.inline.hpp"
	#include "runtime/vmOperations.hpp"
	#include "utilities/globalDefinitions.hpp"
	#include "utilities/macros.hpp"
	#include "utilities/preserveException.hpp"

	// Wrapper for all entry points to the virtual machine.

	// InterfaceSupport provides functionality used by the VM_LEAF_BASE and
	// VM_ENTRY_BASE macros. These macros are used to guard entry points into
	// the VM and perform checks upon leave of the VM.


	class InterfaceSupport: AllStatic {
	# ifdef ASSERT
	public:
	static unsigned int _scavenge_alot_counter;
	static unsigned int _fullgc_alot_counter;
	static intx _fullgc_alot_invocation;

	// Helper methods used to implement +ScavengeALot and +FullGCALot
	static void check_gc_alot() { if (ScavengeALot \|\| FullGCALot) gc_alot(); }
	static void gc_alot();

	static void walk_stack_from(vframe* start_vf);
	static void walk_stack();

	static void zombieAll();
	static void deoptimizeAll();
	static void verify_stack();
	static void verify_last_frame();
	# endif
	};


	// Basic class for all thread transition classes.

	class ThreadStateTransition : public StackObj {
	protected:
	JavaThread* _thread;

	public:
	ThreadStateTransition(JavaThread *thread) : _thread(thread) {
	assert(thread != nullptr, "must be active Java thread");
	assert(thread == Thread::current(), "must be current thread");
	}

	static inline void transition_from_java(JavaThread *thread, JavaThreadState to) {
	assert(thread->thread_state() == _thread_in_Java, "coming from wrong thread state");
	assert(to == _thread_in_vm \|\| to == _thread_in_native, "invalid transition");
	thread->set_thread_state(to);
	}

	// We never install asynchronous exceptions when coming (back) in to the runtime
	// from native code because the runtime is not set up to handle exceptions floating
	// around at arbitrary points.
	static inline void transition_from_native(JavaThread *thread, JavaThreadState to, bool check_asyncs = true) {
	assert(thread->thread_state() == _thread_in_native, "coming from wrong thread state");
	assert(to == _thread_in_vm \|\| to == _thread_in_Java, "invalid transition");
	assert(!thread->has_last_Java_frame() \|\| thread->frame_anchor()->walkable(), "Unwalkable stack in native transition");

	if (!UseSystemMemoryBarrier) {
	thread->set_thread_state_fence(_thread_in_vm);
	} else {
	thread->set_thread_state(_thread_in_vm);
	}
	SafepointMechanism::process_if_requested_with_exit_check(thread, to != _thread_in_Java ? false : check_asyncs);
	thread->set_thread_state(to);
	}

	static inline void transition_from_vm(JavaThread *thread, JavaThreadState to, bool check_asyncs = true) {
	assert(thread->thread_state() == _thread_in_vm, "coming from wrong thread state");
	if (to == _thread_in_Java) {
	SafepointMechanism::process_if_requested_with_exit_check(thread, check_asyncs);
	thread->set_thread_state(to);
	} else {
	assert(to == _thread_in_native \|\| to == _thread_blocked, "invalid transition");
	// Check NoSafepointVerifier. This also clears unhandled oops if CheckUnhandledOops is used.
	thread->check_possible_safepoint();

	// Once we are in native/blocked vm expects stack to be walkable
	thread->frame_anchor()->make_walkable();
	OrderAccess::storestore(); // Keep thread_state change and make_walkable() separate.
	thread->set_thread_state(to);
	}
	}
	};

	class ThreadInVMfromJava : public ThreadStateTransition {
	bool _check_asyncs;
	public:
	ThreadInVMfromJava(JavaThread* thread, bool check_asyncs = true) : ThreadStateTransition(thread), _check_asyncs(check_asyncs) {
	transition_from_java(thread, _thread_in_vm);
	}
	~ThreadInVMfromJava() {
	if (_thread->stack_overflow_state()->stack_yellow_reserved_zone_disabled()) {
	_thread->stack_overflow_state()->enable_stack_yellow_reserved_zone();
	}
	// We prevent asynchronous exceptions from being installed on return to Java in situations
	// where we can't tolerate them. See bugs: 4324348, 4854693, 4998314, 5040492, 5050705.
	transition_from_vm(_thread, _thread_in_Java, _check_asyncs);
	}
	};


	class ThreadInVMfromUnknown {
	JavaThread* _thread;
	public:
	ThreadInVMfromUnknown() : _thread(nullptr) {
	Thread* t = Thread::current();
	if (t->is_Java_thread()) {
	JavaThread* t2 = JavaThread::cast(t);
	if (t2->thread_state() == _thread_in_native) {
	_thread = t2;
	ThreadStateTransition::transition_from_native(t2, _thread_in_vm);
	// Used to have a HandleMarkCleaner but that is dangerous as
	// it could free a handle in our (indirect, nested) caller.
	// We expect any handles will be short lived and figure we
	// don't need an actual HandleMark.
	}
	}
	}
	~ThreadInVMfromUnknown() {
	if (_thread) {
	ThreadStateTransition::transition_from_vm(_thread, _thread_in_native);
	}
	}
	};


	class ThreadInVMfromNative : public ThreadStateTransition {
	ResetNoHandleMark __rnhm;
	public:
	ThreadInVMfromNative(JavaThread* thread) : ThreadStateTransition(thread) {
	transition_from_native(thread, _thread_in_vm);
	}
	~ThreadInVMfromNative() {
	// We cannot assert !_thread->owns_locks() since we have valid cases where
	// we call known native code using this wrapper holding locks.
	transition_from_vm(_thread, _thread_in_native);
	}
	};


	class ThreadToNativeFromVM : public ThreadStateTransition {
	public:
	ThreadToNativeFromVM(JavaThread *thread) : ThreadStateTransition(thread) {
	assert(!thread->owns_locks(), "must release all locks when leaving VM");
	transition_from_vm(thread, _thread_in_native);
	}
	~ThreadToNativeFromVM() {
	transition_from_native(_thread, _thread_in_vm);
	assert(!_thread->is_pending_jni_exception_check(), "Pending JNI Exception Check");
	// We don't need to clear_walkable because it will happen automagically when we return to java
	}
	};

	// Perform a transition to _thread_blocked and take a call-back to be executed before
	// SafepointMechanism::process_if_requested when returning to the VM. This allows us
	// to perform an "undo" action if we might block processing a safepoint/handshake operation
	// (such as thread suspension).
	template <typename PRE_PROC = void(JavaThread*)>
	class ThreadBlockInVMPreprocess : public ThreadStateTransition {
	private:
	PRE_PROC& _pr;
	bool _allow_suspend;
	public:
	ThreadBlockInVMPreprocess(JavaThread* thread, PRE_PROC& pr, bool allow_suspend = false)
	: ThreadStateTransition(thread), _pr(pr), _allow_suspend(allow_suspend) {
	transition_from_vm(thread, _thread_blocked);
	}
	~ThreadBlockInVMPreprocess() {
	assert(_thread->thread_state() == _thread_blocked, "coming from wrong thread state");
	// Change back to _thread_in_vm and ensure it is seen by the VM thread.
	_thread->set_thread_state_fence(_thread_in_vm);

	if (SafepointMechanism::should_process(_thread, _allow_suspend)) {
	_pr(_thread);
	SafepointMechanism::process_if_requested(_thread, _allow_suspend, false /* check_async_exception */);
	}
	}
	};

	class ThreadBlockInVM : public ThreadBlockInVMPreprocess<> {
	public:
	ThreadBlockInVM(JavaThread* thread, bool allow_suspend = false)
	: ThreadBlockInVMPreprocess(thread, emptyOp, allow_suspend) {}
	private:
	static void emptyOp(JavaThread* current) {}
	};


	// Debug class instantiated in JRT_ENTRY macro.
	// Can be used to verify properties on enter/exit of the VM.

	#ifdef ASSERT
	class VMEntryWrapper {
	public:
	VMEntryWrapper();
	~VMEntryWrapper();
	};


	class VMNativeEntryWrapper {
	public:
	VMNativeEntryWrapper();
	~VMNativeEntryWrapper();
	};

	#endif // ASSERT

	// LEAF routines do not lock, GC or throw exceptions

	// On macos/aarch64 we need to maintain the W^X state of the thread. So we
	// take WXWrite on the enter to VM from the "outside" world, so the rest of JVM
	// code can assume writing (but not executing) codecache is always possible
	// without preliminary actions.
	// JavaThread state should be changed only after taking WXWrite. The state
	// change may trigger a safepoint, that would need WXWrite to do bookkeeping
	// in the codecache.

	#define VM_LEAF_BASE(result_type, header) \
	debug_only(NoHandleMark __hm;) \
	os::verify_stack_alignment(); \
	/* begin of body */

	#define VM_ENTRY_BASE_FROM_LEAF(result_type, header, thread) \
	debug_only(ResetNoHandleMark __rnhm;) \
	HandleMarkCleaner __hm(thread); \
	JavaThread* THREAD = thread; /* For exception macros. */ \
	os::verify_stack_alignment(); \
	/* begin of body */


	// ENTRY routines may lock, GC and throw exceptions

	#define VM_ENTRY_BASE(result_type, header, thread) \
	HandleMarkCleaner __hm(thread); \
	JavaThread* THREAD = thread; /* For exception macros. */ \
	os::verify_stack_alignment(); \
	/* begin of body */


	#define JRT_ENTRY(result_type, header) \
	result_type header { \
	assert(current == JavaThread::current(), "Must be"); \
	MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, current)); \
	ThreadInVMfromJava __tiv(current); \
	VM_ENTRY_BASE(result_type, header, current) \
	debug_only(VMEntryWrapper __vew;)

	// JRT_LEAF currently can be called from either _thread_in_Java or
	// _thread_in_native mode.
	//
	// JRT_LEAF rules:
	// A JRT_LEAF method may not interfere with safepointing by
	// 1) acquiring or blocking on a Mutex or JavaLock - checked
	// 2) allocating heap memory - checked
	// 3) executing a VM operation - checked
	// 4) executing a system call (including malloc) that could block or grab a lock
	// 5) invoking GC
	// 6) reaching a safepoint
	// 7) running too long
	// Nor may any method it calls.

	#define JRT_LEAF(result_type, header) \
	result_type header { \
	VM_LEAF_BASE(result_type, header) \
	debug_only(NoSafepointVerifier __nsv;)


	#define JRT_ENTRY_NO_ASYNC(result_type, header) \
	result_type header { \
	assert(current == JavaThread::current(), "Must be"); \
	MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, current)); \
	ThreadInVMfromJava __tiv(current, false /* check asyncs */); \
	VM_ENTRY_BASE(result_type, header, current) \
	debug_only(VMEntryWrapper __vew;)

	// Same as JRT Entry but allows for return value after the safepoint
	// to get back into Java from the VM
	#define JRT_BLOCK_ENTRY(result_type, header) \
	result_type header { \
	assert(current == JavaThread::current(), "Must be"); \
	MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, current)); \
	HandleMarkCleaner __hm(current);

	#define JRT_BLOCK \
	{ \
	assert(current == JavaThread::current(), "Must be"); \
	ThreadInVMfromJava __tiv(current); \
	JavaThread* THREAD = current; /* For exception macros. */ \
	debug_only(VMEntryWrapper __vew;)

	#define JRT_BLOCK_NO_ASYNC \
	{ \
	assert(current == JavaThread::current(), "Must be"); \
	ThreadInVMfromJava __tiv(current, false /* check asyncs */); \
	JavaThread* THREAD = current; /* For exception macros. */ \
	debug_only(VMEntryWrapper __vew;)

	#define JRT_BLOCK_END }

	#define JRT_END }

	// Definitions for JNI
	//
	// As the JNIEnv can be passed from external native code we validate
	// it in debug builds, primarily for our own testing. In general JNI
	// does not attempt to detect programming errors and a bad JNIEnv may
	// not even be readable.

	#define JNI_ENTRY(result_type, header) \
	JNI_ENTRY_NO_PRESERVE(result_type, header) \
	WeakPreserveExceptionMark __wem(thread);

	#define JNI_ENTRY_NO_PRESERVE(result_type, header) \
	extern "C" { \
	result_type JNICALL header { \
	JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
	assert(thread == Thread::current(), "JNIEnv is only valid in same thread"); \
	MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, thread)); \
	ThreadInVMfromNative __tiv(thread); \
	debug_only(VMNativeEntryWrapper __vew;) \
	VM_ENTRY_BASE(result_type, header, thread)


	#define JNI_LEAF(result_type, header) \
	extern "C" { \
	result_type JNICALL header { \
	JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
	assert(thread == Thread::current(), "JNIEnv is only valid in same thread"); \
	VM_LEAF_BASE(result_type, header)


	// Close the routine and the extern "C"
	#define JNI_END } }



	// Definitions for JVM

	#define JVM_ENTRY(result_type, header) \
	extern "C" { \
	result_type JNICALL header { \
	JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
	MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, thread)); \
	ThreadInVMfromNative __tiv(thread); \
	debug_only(VMNativeEntryWrapper __vew;) \
	VM_ENTRY_BASE(result_type, header, thread)


	#define JVM_ENTRY_NO_ENV(result_type, header) \
	extern "C" { \
	result_type JNICALL header { \
	JavaThread* thread = JavaThread::current(); \
	MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, thread)); \
	ThreadInVMfromNative __tiv(thread); \
	debug_only(VMNativeEntryWrapper __vew;) \
	VM_ENTRY_BASE(result_type, header, thread)


	#define JVM_LEAF(result_type, header) \
	extern "C" { \
	result_type JNICALL header { \
	VM_Exit::block_if_vm_exited(); \
	VM_LEAF_BASE(result_type, header)


	#define JVM_ENTRY_FROM_LEAF(env, result_type, header) \
	{ { \
	JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
	MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, thread)); \
	ThreadInVMfromNative __tiv(thread); \
	debug_only(VMNativeEntryWrapper __vew;) \
	VM_ENTRY_BASE_FROM_LEAF(result_type, header, thread)


	#define JVM_END } }

	#endif // SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP