/*
* 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 <stdint.h>
#include <list>
#include <unordered_set>
#include "arch/instruction_set.h"
#include "base/macros.h"
#include "base/mutex.h"
#include "gc_root.h"
#include "safe_map.h"
namespace art {
namespace mirror {
class Class;
class Object;
class Throwable;
} // namespace mirror
class ArtField;
class ArtMethod;
union JValue;
class Thread;
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
};
// Do we want to deoptimize for method entry and exit listeners or just try to intercept
// invocations? Deoptimization forces all code to run in the interpreter and considerably hurts the
// application's performance.
static constexpr bool kDeoptimizeForAccurateMethodEntryExitListeners = true;
// 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,
ArtMethod* method,
uint32_t dex_pc) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;
// Call-back for when a method is exited.
virtual void MethodExited(Thread* thread, mirror::Object* this_object,
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,
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,
ArtMethod* method, uint32_t new_dex_pc)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;
// Call-back for when we read from a field.
virtual void FieldRead(Thread* thread, mirror::Object* this_object, ArtMethod* method,
uint32_t dex_pc, ArtField* field) = 0;
// Call-back for when we write into a field.
virtual void FieldWritten(Thread* thread, mirror::Object* this_object, ArtMethod* method,
uint32_t dex_pc, ArtField* field, const JValue& field_value) = 0;
// Call-back when an exception is caught.
virtual void ExceptionCaught(Thread* thread, mirror::Throwable* exception_object)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;
// Call-back for when we get a backward branch.
virtual void BackwardBranch(Thread* thread, ArtMethod* method, int32_t dex_pc_offset)
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 = 0x1,
kMethodExited = 0x2,
kMethodUnwind = 0x4,
kDexPcMoved = 0x8,
kFieldRead = 0x10,
kFieldWritten = 0x20,
kExceptionCaught = 0x40,
kBackwardBranch = 0x80,
};
enum class InstrumentationLevel {
kInstrumentNothing, // execute without instrumentation
kInstrumentWithInstrumentationStubs, // execute with instrumentation entry/exit stubs
kInstrumentWithInterpreter // execute with interpreter
};
Instrumentation();
// 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_)
LOCKS_EXCLUDED(deoptimized_methods_lock_);
void DisableDeoptimization(const char* key)
EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
LOCKS_EXCLUDED(deoptimized_methods_lock_);
bool AreAllMethodsDeoptimized() const {
return interpreter_stubs_installed_;
}
bool ShouldNotifyMethodEnterExitEvents() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
// Executes everything with interpreter.
void DeoptimizeEverything(const char* key)
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(const char* key)
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(ArtMethod* method)
LOCKS_EXCLUDED(Locks::thread_list_lock_, deoptimized_methods_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(ArtMethod* method)
LOCKS_EXCLUDED(Locks::thread_list_lock_, deoptimized_methods_lock_)
EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_);
// Indicates whether the method has been deoptimized so it is executed with the interpreter.
bool IsDeoptimized(ArtMethod* method)
LOCKS_EXCLUDED(deoptimized_methods_lock_)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
// Enable method tracing by installing instrumentation entry/exit stubs or interpreter.
void EnableMethodTracing(const char* key,
bool needs_interpreter = kDeoptimizeForAccurateMethodEntryExitListeners)
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 or interpreter.
void DisableMethodTracing(const char* key)
EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_);
InterpreterHandlerTable GetInterpreterHandlerTable() const
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return interpreter_handler_table_;
}
void InstrumentQuickAllocEntryPoints() LOCKS_EXCLUDED(Locks::instrument_entrypoints_lock_);
void UninstrumentQuickAllocEntryPoints() LOCKS_EXCLUDED(Locks::instrument_entrypoints_lock_);
void InstrumentQuickAllocEntryPointsLocked()
EXCLUSIVE_LOCKS_REQUIRED(Locks::instrument_entrypoints_lock_)
LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::runtime_shutdown_lock_);
void UninstrumentQuickAllocEntryPointsLocked()
EXCLUSIVE_LOCKS_REQUIRED(Locks::instrument_entrypoints_lock_)
LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::runtime_shutdown_lock_);
void ResetQuickAllocEntryPoints() EXCLUSIVE_LOCKS_REQUIRED(Locks::runtime_shutdown_lock_);
// Update the code of a method respecting any installed stubs.
void UpdateMethodsCode(ArtMethod* method, const void* quick_code)
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(ArtMethod* method, size_t pointer_size) 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 IsForcedInterpretOnly() const {
return forced_interpret_only_;
}
bool AreExitStubsInstalled() const {
return instrumentation_stubs_installed_;
}
bool HasMethodEntryListeners() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return have_method_entry_listeners_;
}
bool HasMethodExitListeners() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return have_method_exit_listeners_;
}
bool HasMethodUnwindListeners() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return have_method_unwind_listeners_;
}
bool HasDexPcListeners() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return have_dex_pc_listeners_;
}
bool HasFieldReadListeners() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return have_field_read_listeners_;
}
bool HasFieldWriteListeners() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return have_field_write_listeners_;
}
bool HasExceptionCaughtListeners() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return have_exception_caught_listeners_;
}
bool HasBackwardBranchListeners() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return have_backward_branch_listeners_;
}
bool IsActive() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return have_dex_pc_listeners_ || have_method_entry_listeners_ || have_method_exit_listeners_ ||
have_field_read_listeners_ || have_field_write_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,
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,
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,
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,
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 a backward branch has been taken (only supported by the interpreter).
void BackwardBranch(Thread* thread, ArtMethod* method, int32_t offset) const
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
if (UNLIKELY(HasBackwardBranchListeners())) {
BackwardBranchImpl(thread, method, offset);
}
}
// Inform listeners that we read a field (only supported by the interpreter).
void FieldReadEvent(Thread* thread, mirror::Object* this_object,
ArtMethod* method, uint32_t dex_pc,
ArtField* field) const
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
if (UNLIKELY(HasFieldReadListeners())) {
FieldReadEventImpl(thread, this_object, method, dex_pc, field);
}
}
// Inform listeners that we write a field (only supported by the interpreter).
void FieldWriteEvent(Thread* thread, mirror::Object* this_object,
ArtMethod* method, uint32_t dex_pc,
ArtField* field, const JValue& field_value) const
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
if (UNLIKELY(HasFieldWriteListeners())) {
FieldWriteEventImpl(thread, this_object, method, dex_pc, field, field_value);
}
}
// Inform listeners that an exception was caught.
void ExceptionCaughtEvent(Thread* thread, 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,
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.
TwoWordReturn 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.
void InstallStubsForClass(mirror::Class* klass) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
void InstallStubsForMethod(ArtMethod* method)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
private:
InstrumentationLevel GetCurrentInstrumentationLevel() const;
// Does the job of installing or removing instrumentation code within methods.
// In order to support multiple clients using instrumentation at the same time,
// the caller must pass a unique key (a string) identifying it so we remind which
// instrumentation level it needs. Therefore the current instrumentation level
// becomes the highest instrumentation level required by a client.
void ConfigureStubs(const char* key, InstrumentationLevel desired_instrumentation_level)
EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_)
LOCKS_EXCLUDED(Locks::thread_list_lock_, Locks::classlinker_classes_lock_,
deoptimized_methods_lock_);
void UpdateInterpreterHandlerTable() EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_) {
interpreter_handler_table_ = IsActive() ? kAlternativeHandlerTable : kMainHandlerTable;
}
// No thread safety analysis to get around SetQuickAllocEntryPointsInstrumented requiring
// exclusive access to mutator lock which you can't get if the runtime isn't started.
void SetEntrypointsInstrumented(bool instrumented) NO_THREAD_SAFETY_ANALYSIS;
void MethodEnterEventImpl(Thread* thread, mirror::Object* this_object,
ArtMethod* method, uint32_t dex_pc) const
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
void MethodExitEventImpl(Thread* thread, mirror::Object* this_object,
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,
ArtMethod* method, uint32_t dex_pc) const
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
void BackwardBranchImpl(Thread* thread, ArtMethod* method, int32_t offset) const
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
void FieldReadEventImpl(Thread* thread, mirror::Object* this_object,
ArtMethod* method, uint32_t dex_pc,
ArtField* field) const
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
void FieldWriteEventImpl(Thread* thread, mirror::Object* this_object,
ArtMethod* method, uint32_t dex_pc,
ArtField* field, const JValue& field_value) const
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
// Read barrier-aware utility functions for accessing deoptimized_methods_
bool AddDeoptimizedMethod(ArtMethod* method)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
EXCLUSIVE_LOCKS_REQUIRED(deoptimized_methods_lock_);
bool IsDeoptimizedMethod(ArtMethod* method)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, deoptimized_methods_lock_);
bool RemoveDeoptimizedMethod(ArtMethod* method)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
EXCLUSIVE_LOCKS_REQUIRED(deoptimized_methods_lock_);
ArtMethod* BeginDeoptimizedMethod()
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, deoptimized_methods_lock_);
bool IsDeoptimizedMethodsEmpty() const
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_, deoptimized_methods_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_ GUARDED_BY(Locks::mutator_lock_);
// Do we have any listeners for method exit events? Short-cut to avoid taking the
// instrumentation_lock_.
bool have_method_exit_listeners_ GUARDED_BY(Locks::mutator_lock_);
// Do we have any listeners for method unwind events? Short-cut to avoid taking the
// instrumentation_lock_.
bool have_method_unwind_listeners_ GUARDED_BY(Locks::mutator_lock_);
// Do we have any listeners for dex move events? Short-cut to avoid taking the
// instrumentation_lock_.
bool have_dex_pc_listeners_ GUARDED_BY(Locks::mutator_lock_);
// Do we have any listeners for field read events? Short-cut to avoid taking the
// instrumentation_lock_.
bool have_field_read_listeners_ GUARDED_BY(Locks::mutator_lock_);
// Do we have any listeners for field write events? Short-cut to avoid taking the
// instrumentation_lock_.
bool have_field_write_listeners_ GUARDED_BY(Locks::mutator_lock_);
// Do we have any exception caught listeners? Short-cut to avoid taking the instrumentation_lock_.
bool have_exception_caught_listeners_ GUARDED_BY(Locks::mutator_lock_);
// Do we have any backward branch listeners? Short-cut to avoid taking the instrumentation_lock_.
bool have_backward_branch_listeners_ GUARDED_BY(Locks::mutator_lock_);
// Contains the instrumentation level required by each client of the instrumentation identified
// by a string key.
typedef SafeMap<const char*, InstrumentationLevel> InstrumentationLevelTable;
InstrumentationLevelTable requested_instrumentation_levels_ GUARDED_BY(Locks::mutator_lock_);
// 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*> backward_branch_listeners_ GUARDED_BY(Locks::mutator_lock_);
std::shared_ptr<std::list<InstrumentationListener*>> dex_pc_listeners_
GUARDED_BY(Locks::mutator_lock_);
std::shared_ptr<std::list<InstrumentationListener*>> field_read_listeners_
GUARDED_BY(Locks::mutator_lock_);
std::shared_ptr<std::list<InstrumentationListener*>> field_write_listeners_
GUARDED_BY(Locks::mutator_lock_);
std::shared_ptr<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.
mutable ReaderWriterMutex deoptimized_methods_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER;
std::unordered_set<ArtMethod*> deoptimized_methods_ GUARDED_BY(deoptimized_methods_lock_);
bool deoptimization_enabled_;
// Current interpreter handler table. This is updated each time the thread state flags are
// modified.
InterpreterHandlerTable interpreter_handler_table_ GUARDED_BY(Locks::mutator_lock_);
// Greater than 0 if quick alloc entry points instrumented.
size_t quick_alloc_entry_points_instrumentation_counter_
GUARDED_BY(Locks::instrument_entrypoints_lock_);
friend class InstrumentationTest; // For GetCurrentInstrumentationLevel and ConfigureStubs.
DISALLOW_COPY_AND_ASSIGN(Instrumentation);
};
std::ostream& operator<<(std::ostream& os, const Instrumentation::InstrumentationEvent& rhs);
std::ostream& operator<<(std::ostream& os, const Instrumentation::InstrumentationLevel& rhs);
// An element in the instrumentation side stack maintained in art::Thread.
struct InstrumentationStackFrame {
InstrumentationStackFrame(mirror::Object* this_object, 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_;
ArtMethod* method_;
uintptr_t return_pc_;
size_t frame_id_;
bool interpreter_entry_;
};
} // namespace instrumentation
} // namespace art
#endif // ART_RUNTIME_INSTRUMENTATION_H_