runtime/instrumentation.h - platform/art - Gitiles

 /*
  * Copyright (C) 2011 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #ifndef ART_RUNTIME_INSTRUMENTATION_H_
 #define ART_RUNTIME_INSTRUMENTATION_H_

 #include "atomic_integer.h"
 #include "base/macros.h"
 #include "locks.h"

 #include <stdint.h>
 #include <set>
 #include <list>

 namespace art {
 namespace mirror {
   class ArtMethod;
   class Class;
   class Object;
   class Throwable;
 }  // namespace mirror
 union JValue;
 class Thread;
 class ThrowLocation;

 namespace instrumentation {

 // Interpreter handler tables.
 enum InterpreterHandlerTable {
   kMainHandlerTable = 0,          // Main handler table: no suspend check, no instrumentation.
   kAlternativeHandlerTable = 1,   // Alternative handler table: suspend check and/or instrumentation
                                   // enabled.
   kNumHandlerTables
 };

 // Instrumentation event listener API. Registered listeners will get the appropriate call back for
 // the events they are listening for. The call backs supply the thread, method and dex_pc the event
 // occurred upon. The thread may or may not be Thread::Current().
 struct InstrumentationListener {
   InstrumentationListener() {}
   virtual ~InstrumentationListener() {}

   // Call-back for when a method is entered.
   virtual void MethodEntered(Thread* thread, mirror::Object* this_object,
                              const mirror::ArtMethod* method,
                              uint32_t dex_pc) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;

   // Call-back for when a method is exited.
   // TODO: its likely passing the return value would be useful, however, we may need to get and
   //       parse the shorty to determine what kind of register holds the result.
   virtual void MethodExited(Thread* thread, mirror::Object* this_object,
                             const mirror::ArtMethod* method, uint32_t dex_pc,
                             const JValue& return_value)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;

   // Call-back for when a method is popped due to an exception throw. A method will either cause a
   // MethodExited call-back or a MethodUnwind call-back when its activation is removed.
   virtual void MethodUnwind(Thread* thread, mirror::Object* this_object,
                             const mirror::ArtMethod* method, uint32_t dex_pc)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;

   // Call-back for when the dex pc moves in a method.
   virtual void DexPcMoved(Thread* thread, mirror::Object* this_object,
                           const mirror::ArtMethod* method, uint32_t new_dex_pc)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;

   // Call-back when an exception is caught.
   virtual void ExceptionCaught(Thread* thread, const ThrowLocation& throw_location,
                                mirror::ArtMethod* catch_method, uint32_t catch_dex_pc,
                                mirror::Throwable* exception_object)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;
 };

 // Instrumentation is a catch-all for when extra information is required from the runtime. The
 // typical use for instrumentation is for profiling and debugging. Instrumentation may add stubs
 // to method entry and exit, it may also force execution to be switched to the interpreter and
 // trigger deoptimization.
 class Instrumentation {
  public:
   enum InstrumentationEvent {
     kMethodEntered = 1,
     kMethodExited = 2,
     kMethodUnwind = 4,
     kDexPcMoved = 8,
     kExceptionCaught = 16
   };

   Instrumentation() :
       instrumentation_stubs_installed_(false), entry_exit_stubs_installed_(false),
       interpreter_stubs_installed_(false),
       interpret_only_(false), forced_interpret_only_(false),
       have_method_entry_listeners_(false), have_method_exit_listeners_(false),
       have_method_unwind_listeners_(false), have_dex_pc_listeners_(false),
       have_exception_caught_listeners_(false),
       interpreter_handler_table_(kMainHandlerTable),
       quick_alloc_entry_points_instrumentation_counter_(0) {}

   // Add a listener to be notified of the masked together sent of instrumentation events. This
   // suspend the runtime to install stubs. You are expected to hold the mutator lock as a proxy
   // for saying you should have suspended all threads (installing stubs while threads are running
   // will break).
   void AddListener(InstrumentationListener* listener, uint32_t events)
       EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
       LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

   // Removes a listener possibly removing instrumentation stubs.
   void RemoveListener(InstrumentationListener* listener, uint32_t events)
       EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
       LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

   // Deoptimization.
   void EnableDeoptimization() EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);
   void DisableDeoptimization() EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);
   bool IsDeoptimizationEnabled() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

   // Executes everything with interpreter.
   void DeoptimizeEverything()
       EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
       LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

   // Executes everything with compiled code (or interpreter if there is no code).
   void UndeoptimizeEverything()
       EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
       LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

   // Deoptimize a method by forcing its execution with the interpreter. Nevertheless, a static
   // method (except a class initializer) set to the resolution trampoline will be deoptimized only
   // once its declaring class is initialized.
   void Deoptimize(mirror::ArtMethod* method)
       LOCKS_EXCLUDED(Locks::thread_list_lock_)
       EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);

   // Undeoptimze the method by restoring its entrypoints. Nevertheless, a static method
   // (except a class initializer) set to the resolution trampoline will be updated only once its
   // declaring class is initialized.
   void Undeoptimize(mirror::ArtMethod* method)
       LOCKS_EXCLUDED(Locks::thread_list_lock_)
       EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);

   bool IsDeoptimized(mirror::ArtMethod* method) const;

   // Enable method tracing by installing instrumentation entry/exit stubs.
   void EnableMethodTracing()
       EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
       LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

   // Disable method tracing by uninstalling instrumentation entry/exit stubs.
   void DisableMethodTracing()
       EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
       LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

   InterpreterHandlerTable GetInterpreterHandlerTable() const {
     return interpreter_handler_table_;
   }

   void InstrumentQuickAllocEntryPoints() LOCKS_EXCLUDED(Locks::thread_list_lock_);
   void UninstrumentQuickAllocEntryPoints() LOCKS_EXCLUDED(Locks::thread_list_lock_);
   void ResetQuickAllocEntryPoints();

   // Update the code of a method respecting any installed stubs.
   void UpdateMethodsCode(mirror::ArtMethod* method, const void* code) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

   // Get the quick code for the given method. More efficient than asking the class linker as it
   // will short-cut to GetCode if instrumentation and static method resolution stubs aren't
   // installed.
   const void* GetQuickCodeFor(const mirror::ArtMethod* method) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

   void ForceInterpretOnly() {
     interpret_only_ = true;
     forced_interpret_only_ = true;
   }

   // Called by ArtMethod::Invoke to determine dispatch mechanism.
   bool InterpretOnly() const {
     return interpret_only_;
   }

   bool ShouldPortableCodeDeoptimize() const {
     return instrumentation_stubs_installed_;
   }

   bool AreExitStubsInstalled() const {
     return instrumentation_stubs_installed_;
   }

   bool HasMethodEntryListeners() const {
     return have_method_entry_listeners_;
   }

   bool HasMethodExitListeners() const {
     return have_method_exit_listeners_;
   }

   bool HasDexPcListeners() const {
     return have_dex_pc_listeners_;
   }

   bool IsActive() const {
     return have_dex_pc_listeners_ || have_method_entry_listeners_ || have_method_exit_listeners_ ||
         have_exception_caught_listeners_ || have_method_unwind_listeners_;
   }

   // Inform listeners that a method has been entered. A dex PC is provided as we may install
   // listeners into executing code and get method enter events for methods already on the stack.
   void MethodEnterEvent(Thread* thread, mirror::Object* this_object,
                         const mirror::ArtMethod* method, uint32_t dex_pc) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     if (UNLIKELY(HasMethodEntryListeners())) {
       MethodEnterEventImpl(thread, this_object, method, dex_pc);
     }
   }

   // Inform listeners that a method has been exited.
   void MethodExitEvent(Thread* thread, mirror::Object* this_object,
                        const mirror::ArtMethod* method, uint32_t dex_pc,
                        const JValue& return_value) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     if (UNLIKELY(HasMethodExitListeners())) {
       MethodExitEventImpl(thread, this_object, method, dex_pc, return_value);
     }
   }

   // Inform listeners that a method has been exited due to an exception.
   void MethodUnwindEvent(Thread* thread, mirror::Object* this_object,
                          const mirror::ArtMethod* method, uint32_t dex_pc) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

   // Inform listeners that the dex pc has moved (only supported by the interpreter).
   void DexPcMovedEvent(Thread* thread, mirror::Object* this_object,
                        const mirror::ArtMethod* method, uint32_t dex_pc) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     if (UNLIKELY(HasDexPcListeners())) {
       DexPcMovedEventImpl(thread, this_object, method, dex_pc);
     }
   }

   // Inform listeners that an exception was caught.
   void ExceptionCaughtEvent(Thread* thread, const ThrowLocation& throw_location,
                             mirror::ArtMethod* catch_method, uint32_t catch_dex_pc,
                             mirror::Throwable* exception_object) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

   // Called when an instrumented method is entered. The intended link register (lr) is saved so
   // that returning causes a branch to the method exit stub. Generates method enter events.
   void PushInstrumentationStackFrame(Thread* self, mirror::Object* this_object,
                                      mirror::ArtMethod* method, uintptr_t lr,
                                      bool interpreter_entry)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

   // Called when an instrumented method is exited. Removes the pushed instrumentation frame
   // returning the intended link register. Generates method exit events.
   uint64_t PopInstrumentationStackFrame(Thread* self, uintptr_t* return_pc, uint64_t gpr_result,
                                         uint64_t fpr_result)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

   // Pops an instrumentation frame from the current thread and generate an unwind event.
   void PopMethodForUnwind(Thread* self, bool is_deoptimization) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

   // Call back for configure stubs.
   bool InstallStubsForClass(mirror::Class* klass) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

   void InstallStubsForMethod(mirror::ArtMethod* method)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

  private:
   // Does the job of installing or removing instrumentation code within methods.
   void ConfigureStubs(bool require_entry_exit_stubs, bool require_interpreter)
       EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
       LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

   void UpdateInterpreterHandlerTable() {
     interpreter_handler_table_ = IsActive() ? kAlternativeHandlerTable : kMainHandlerTable;
   }

   void MethodEnterEventImpl(Thread* thread, mirror::Object* this_object,
                             const mirror::ArtMethod* method, uint32_t dex_pc) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   void MethodExitEventImpl(Thread* thread, mirror::Object* this_object,
                            const mirror::ArtMethod* method,
                            uint32_t dex_pc, const JValue& return_value) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
   void DexPcMovedEventImpl(Thread* thread, mirror::Object* this_object,
                            const mirror::ArtMethod* method, uint32_t dex_pc) const
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

   // Have we hijacked ArtMethod::code_ so that it calls instrumentation/interpreter code?
   bool instrumentation_stubs_installed_;

   // Have we hijacked ArtMethod::code_ to reference the enter/exit stubs?
   bool entry_exit_stubs_installed_;

   // Have we hijacked ArtMethod::code_ to reference the enter interpreter stub?
   bool interpreter_stubs_installed_;

   // Do we need the fidelity of events that we only get from running within the interpreter?
   bool interpret_only_;

   // Did the runtime request we only run in the interpreter? ie -Xint mode.
   bool forced_interpret_only_;

   // Do we have any listeners for method entry events? Short-cut to avoid taking the
   // instrumentation_lock_.
   bool have_method_entry_listeners_;

   // Do we have any listeners for method exit events? Short-cut to avoid taking the
   // instrumentation_lock_.
   bool have_method_exit_listeners_;

   // Do we have any listeners for method unwind events? Short-cut to avoid taking the
   // instrumentation_lock_.
   bool have_method_unwind_listeners_;

   // Do we have any listeners for dex move events? Short-cut to avoid taking the
   // instrumentation_lock_.
   bool have_dex_pc_listeners_;

   // Do we have any exception caught listeners? Short-cut to avoid taking the instrumentation_lock_.
   bool have_exception_caught_listeners_;

   // The event listeners, written to with the mutator_lock_ exclusively held.
   std::list<InstrumentationListener*> method_entry_listeners_ GUARDED_BY(Locks::mutator_lock_);
   std::list<InstrumentationListener*> method_exit_listeners_ GUARDED_BY(Locks::mutator_lock_);
   std::list<InstrumentationListener*> method_unwind_listeners_ GUARDED_BY(Locks::mutator_lock_);
   std::list<InstrumentationListener*> dex_pc_listeners_ GUARDED_BY(Locks::mutator_lock_);
   std::list<InstrumentationListener*> exception_caught_listeners_ GUARDED_BY(Locks::mutator_lock_);

   // The set of methods being deoptimized (by the debugger) which must be executed with interpreter
   // only.
   // TODO we need to visit these methods as roots.
   std::set<mirror::ArtMethod*> deoptimized_methods_;

   // Current interpreter handler table. This is updated each time the thread state flags are
   // modified.
   InterpreterHandlerTable interpreter_handler_table_;

   // Greater than 0 if quick alloc entry points instrumented.
   // TODO: The access and changes to this is racy and should be guarded by a lock.
   AtomicInteger quick_alloc_entry_points_instrumentation_counter_;

   DISALLOW_COPY_AND_ASSIGN(Instrumentation);
 };

 // An element in the instrumentation side stack maintained in art::Thread.
 struct InstrumentationStackFrame {
   InstrumentationStackFrame(mirror::Object* this_object, mirror::ArtMethod* method,
                             uintptr_t return_pc, size_t frame_id, bool interpreter_entry)
       : this_object_(this_object), method_(method), return_pc_(return_pc), frame_id_(frame_id),
         interpreter_entry_(interpreter_entry) {
   }

   std::string Dump() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

   mirror::Object* this_object_;
   mirror::ArtMethod* method_;
   uintptr_t return_pc_;
   size_t frame_id_;
   bool interpreter_entry_;
 };

 }  // namespace instrumentation
 }  // namespace art

 #endif  // ART_RUNTIME_INSTRUMENTATION_H_
	/*
	* Copyright (C) 2011 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#ifndef ART_RUNTIME_INSTRUMENTATION_H_
	#define ART_RUNTIME_INSTRUMENTATION_H_

	#include "atomic_integer.h"
	#include "base/macros.h"
	#include "locks.h"

	#include <stdint.h>
	#include <set>
	#include <list>

	namespace art {
	namespace mirror {
	class ArtMethod;
	class Class;
	class Object;
	class Throwable;
	} // namespace mirror
	union JValue;
	class Thread;
	class ThrowLocation;

	namespace instrumentation {

	// Interpreter handler tables.
	enum InterpreterHandlerTable {
	kMainHandlerTable = 0, // Main handler table: no suspend check, no instrumentation.
	kAlternativeHandlerTable = 1, // Alternative handler table: suspend check and/or instrumentation
	// enabled.
	kNumHandlerTables
	};

	// Instrumentation event listener API. Registered listeners will get the appropriate call back for
	// the events they are listening for. The call backs supply the thread, method and dex_pc the event
	// occurred upon. The thread may or may not be Thread::Current().
	struct InstrumentationListener {
	InstrumentationListener() {}
	virtual ~InstrumentationListener() {}

	// Call-back for when a method is entered.
	virtual void MethodEntered(Thread* thread, mirror::Object* this_object,
	const mirror::ArtMethod* method,
	uint32_t dex_pc) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;

	// Call-back for when a method is exited.
	// TODO: its likely passing the return value would be useful, however, we may need to get and
	// parse the shorty to determine what kind of register holds the result.
	virtual void MethodExited(Thread* thread, mirror::Object* this_object,
	const mirror::ArtMethod* method, uint32_t dex_pc,
	const JValue& return_value)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;

	// Call-back for when a method is popped due to an exception throw. A method will either cause a
	// MethodExited call-back or a MethodUnwind call-back when its activation is removed.
	virtual void MethodUnwind(Thread* thread, mirror::Object* this_object,
	const mirror::ArtMethod* method, uint32_t dex_pc)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;

	// Call-back for when the dex pc moves in a method.
	virtual void DexPcMoved(Thread* thread, mirror::Object* this_object,
	const mirror::ArtMethod* method, uint32_t new_dex_pc)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;

	// Call-back when an exception is caught.
	virtual void ExceptionCaught(Thread* thread, const ThrowLocation& throw_location,
	mirror::ArtMethod* catch_method, uint32_t catch_dex_pc,
	mirror::Throwable* exception_object)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;
	};

	// Instrumentation is a catch-all for when extra information is required from the runtime. The
	// typical use for instrumentation is for profiling and debugging. Instrumentation may add stubs
	// to method entry and exit, it may also force execution to be switched to the interpreter and
	// trigger deoptimization.
	class Instrumentation {
	public:
	enum InstrumentationEvent {
	kMethodEntered = 1,
	kMethodExited = 2,
	kMethodUnwind = 4,
	kDexPcMoved = 8,
	kExceptionCaught = 16
	};

	Instrumentation() :
	instrumentation_stubs_installed_(false), entry_exit_stubs_installed_(false),
	interpreter_stubs_installed_(false),
	interpret_only_(false), forced_interpret_only_(false),
	have_method_entry_listeners_(false), have_method_exit_listeners_(false),
	have_method_unwind_listeners_(false), have_dex_pc_listeners_(false),
	have_exception_caught_listeners_(false),
	interpreter_handler_table_(kMainHandlerTable),
	quick_alloc_entry_points_instrumentation_counter_(0) {}

	// Add a listener to be notified of the masked together sent of instrumentation events. This
	// suspend the runtime to install stubs. You are expected to hold the mutator lock as a proxy
	// for saying you should have suspended all threads (installing stubs while threads are running
	// will break).
	void AddListener(InstrumentationListener* listener, uint32_t events)
	EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
	LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

	// Removes a listener possibly removing instrumentation stubs.
	void RemoveListener(InstrumentationListener* listener, uint32_t events)
	EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
	LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

	// Deoptimization.
	void EnableDeoptimization() EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);
	void DisableDeoptimization() EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);
	bool IsDeoptimizationEnabled() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	// Executes everything with interpreter.
	void DeoptimizeEverything()
	EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
	LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

	// Executes everything with compiled code (or interpreter if there is no code).
	void UndeoptimizeEverything()
	EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
	LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

	// Deoptimize a method by forcing its execution with the interpreter. Nevertheless, a static
	// method (except a class initializer) set to the resolution trampoline will be deoptimized only
	// once its declaring class is initialized.
	void Deoptimize(mirror::ArtMethod* method)
	LOCKS_EXCLUDED(Locks::thread_list_lock_)
	EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);

	// Undeoptimze the method by restoring its entrypoints. Nevertheless, a static method
	// (except a class initializer) set to the resolution trampoline will be updated only once its
	// declaring class is initialized.
	void Undeoptimize(mirror::ArtMethod* method)
	LOCKS_EXCLUDED(Locks::thread_list_lock_)
	EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);

	bool IsDeoptimized(mirror::ArtMethod* method) const;

	// Enable method tracing by installing instrumentation entry/exit stubs.
	void EnableMethodTracing()
	EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
	LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

	// Disable method tracing by uninstalling instrumentation entry/exit stubs.
	void DisableMethodTracing()
	EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
	LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

	InterpreterHandlerTable GetInterpreterHandlerTable() const {
	return interpreter_handler_table_;
	}

	void InstrumentQuickAllocEntryPoints() LOCKS_EXCLUDED(Locks::thread_list_lock_);
	void UninstrumentQuickAllocEntryPoints() LOCKS_EXCLUDED(Locks::thread_list_lock_);
	void ResetQuickAllocEntryPoints();

	// Update the code of a method respecting any installed stubs.
	void UpdateMethodsCode(mirror::ArtMethod* method, const void* code) const
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	// Get the quick code for the given method. More efficient than asking the class linker as it
	// will short-cut to GetCode if instrumentation and static method resolution stubs aren't
	// installed.
	const void* GetQuickCodeFor(const mirror::ArtMethod* method) const
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	void ForceInterpretOnly() {
	interpret_only_ = true;
	forced_interpret_only_ = true;
	}

	// Called by ArtMethod::Invoke to determine dispatch mechanism.
	bool InterpretOnly() const {
	return interpret_only_;
	}

	bool ShouldPortableCodeDeoptimize() const {
	return instrumentation_stubs_installed_;
	}

	bool AreExitStubsInstalled() const {
	return instrumentation_stubs_installed_;
	}

	bool HasMethodEntryListeners() const {
	return have_method_entry_listeners_;
	}

	bool HasMethodExitListeners() const {
	return have_method_exit_listeners_;
	}

	bool HasDexPcListeners() const {
	return have_dex_pc_listeners_;
	}

	bool IsActive() const {
	return have_dex_pc_listeners_ \|\| have_method_entry_listeners_ \|\| have_method_exit_listeners_ \|\|
	have_exception_caught_listeners_ \|\| have_method_unwind_listeners_;
	}

	// Inform listeners that a method has been entered. A dex PC is provided as we may install
	// listeners into executing code and get method enter events for methods already on the stack.
	void MethodEnterEvent(Thread* thread, mirror::Object* this_object,
	const mirror::ArtMethod* method, uint32_t dex_pc) const
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	if (UNLIKELY(HasMethodEntryListeners())) {
	MethodEnterEventImpl(thread, this_object, method, dex_pc);
	}
	}

	// Inform listeners that a method has been exited.
	void MethodExitEvent(Thread* thread, mirror::Object* this_object,
	const mirror::ArtMethod* method, uint32_t dex_pc,
	const JValue& return_value) const
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	if (UNLIKELY(HasMethodExitListeners())) {
	MethodExitEventImpl(thread, this_object, method, dex_pc, return_value);
	}
	}

	// Inform listeners that a method has been exited due to an exception.
	void MethodUnwindEvent(Thread* thread, mirror::Object* this_object,
	const mirror::ArtMethod* method, uint32_t dex_pc) const
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	// Inform listeners that the dex pc has moved (only supported by the interpreter).
	void DexPcMovedEvent(Thread* thread, mirror::Object* this_object,
	const mirror::ArtMethod* method, uint32_t dex_pc) const
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
	if (UNLIKELY(HasDexPcListeners())) {
	DexPcMovedEventImpl(thread, this_object, method, dex_pc);
	}
	}

	// Inform listeners that an exception was caught.
	void ExceptionCaughtEvent(Thread* thread, const ThrowLocation& throw_location,
	mirror::ArtMethod* catch_method, uint32_t catch_dex_pc,
	mirror::Throwable* exception_object) const
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	// Called when an instrumented method is entered. The intended link register (lr) is saved so
	// that returning causes a branch to the method exit stub. Generates method enter events.
	void PushInstrumentationStackFrame(Thread* self, mirror::Object* this_object,
	mirror::ArtMethod* method, uintptr_t lr,
	bool interpreter_entry)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	// Called when an instrumented method is exited. Removes the pushed instrumentation frame
	// returning the intended link register. Generates method exit events.
	uint64_t PopInstrumentationStackFrame(Thread* self, uintptr_t* return_pc, uint64_t gpr_result,
	uint64_t fpr_result)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	// Pops an instrumentation frame from the current thread and generate an unwind event.
	void PopMethodForUnwind(Thread* self, bool is_deoptimization) const
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	// Call back for configure stubs.
	bool InstallStubsForClass(mirror::Class* klass) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	void InstallStubsForMethod(mirror::ArtMethod* method)
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	private:
	// Does the job of installing or removing instrumentation code within methods.
	void ConfigureStubs(bool require_entry_exit_stubs, bool require_interpreter)
	EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
	LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);

	void UpdateInterpreterHandlerTable() {
	interpreter_handler_table_ = IsActive() ? kAlternativeHandlerTable : kMainHandlerTable;
	}

	void MethodEnterEventImpl(Thread* thread, mirror::Object* this_object,
	const mirror::ArtMethod* method, uint32_t dex_pc) const
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
	void MethodExitEventImpl(Thread* thread, mirror::Object* this_object,
	const mirror::ArtMethod* method,
	uint32_t dex_pc, const JValue& return_value) const
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
	void DexPcMovedEventImpl(Thread* thread, mirror::Object* this_object,
	const mirror::ArtMethod* method, uint32_t dex_pc) const
	SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	// Have we hijacked ArtMethod::code_ so that it calls instrumentation/interpreter code?
	bool instrumentation_stubs_installed_;

	// Have we hijacked ArtMethod::code_ to reference the enter/exit stubs?
	bool entry_exit_stubs_installed_;

	// Have we hijacked ArtMethod::code_ to reference the enter interpreter stub?
	bool interpreter_stubs_installed_;

	// Do we need the fidelity of events that we only get from running within the interpreter?
	bool interpret_only_;

	// Did the runtime request we only run in the interpreter? ie -Xint mode.
	bool forced_interpret_only_;

	// Do we have any listeners for method entry events? Short-cut to avoid taking the
	// instrumentation_lock_.
	bool have_method_entry_listeners_;

	// Do we have any listeners for method exit events? Short-cut to avoid taking the
	// instrumentation_lock_.
	bool have_method_exit_listeners_;

	// Do we have any listeners for method unwind events? Short-cut to avoid taking the
	// instrumentation_lock_.
	bool have_method_unwind_listeners_;

	// Do we have any listeners for dex move events? Short-cut to avoid taking the
	// instrumentation_lock_.
	bool have_dex_pc_listeners_;

	// Do we have any exception caught listeners? Short-cut to avoid taking the instrumentation_lock_.
	bool have_exception_caught_listeners_;

	// The event listeners, written to with the mutator_lock_ exclusively held.
	std::list<InstrumentationListener*> method_entry_listeners_ GUARDED_BY(Locks::mutator_lock_);
	std::list<InstrumentationListener*> method_exit_listeners_ GUARDED_BY(Locks::mutator_lock_);
	std::list<InstrumentationListener*> method_unwind_listeners_ GUARDED_BY(Locks::mutator_lock_);
	std::list<InstrumentationListener*> dex_pc_listeners_ GUARDED_BY(Locks::mutator_lock_);
	std::list<InstrumentationListener*> exception_caught_listeners_ GUARDED_BY(Locks::mutator_lock_);

	// The set of methods being deoptimized (by the debugger) which must be executed with interpreter
	// only.
	// TODO we need to visit these methods as roots.
	std::set<mirror::ArtMethod*> deoptimized_methods_;

	// Current interpreter handler table. This is updated each time the thread state flags are
	// modified.
	InterpreterHandlerTable interpreter_handler_table_;

	// Greater than 0 if quick alloc entry points instrumented.
	// TODO: The access and changes to this is racy and should be guarded by a lock.
	AtomicInteger quick_alloc_entry_points_instrumentation_counter_;

	DISALLOW_COPY_AND_ASSIGN(Instrumentation);
	};

	// An element in the instrumentation side stack maintained in art::Thread.
	struct InstrumentationStackFrame {
	InstrumentationStackFrame(mirror::Object* this_object, mirror::ArtMethod* method,
	uintptr_t return_pc, size_t frame_id, bool interpreter_entry)
	: this_object_(this_object), method_(method), return_pc_(return_pc), frame_id_(frame_id),
	interpreter_entry_(interpreter_entry) {
	}

	std::string Dump() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);

	mirror::Object* this_object_;
	mirror::ArtMethod* method_;
	uintptr_t return_pc_;
	size_t frame_id_;
	bool interpreter_entry_;
	};

	} // namespace instrumentation
	} // namespace art

	#endif // ART_RUNTIME_INSTRUMENTATION_H_