/*
* 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.
*/
#include "instrumentation.h"
#include <sstream>
#include "arch/context.h"
#include "art_method-inl.h"
#include "atomic.h"
#include "class_linker.h"
#include "debugger.h"
#include "dex_file-inl.h"
#include "entrypoints/quick/quick_entrypoints.h"
#include "entrypoints/quick/quick_alloc_entrypoints.h"
#include "entrypoints/runtime_asm_entrypoints.h"
#include "gc_root-inl.h"
#include "interpreter/interpreter.h"
#include "jit/jit.h"
#include "jit/jit_code_cache.h"
#include "mirror/class-inl.h"
#include "mirror/dex_cache.h"
#include "mirror/object_array-inl.h"
#include "mirror/object-inl.h"
#include "nth_caller_visitor.h"
#include "thread.h"
#include "thread_list.h"
namespace art {
namespace instrumentation {
constexpr bool kVerboseInstrumentation = false;
// Instrumentation works on non-inlined frames by updating returned PCs
// of compiled frames.
static constexpr StackVisitor::StackWalkKind kInstrumentationStackWalk =
StackVisitor::StackWalkKind::kSkipInlinedFrames;
static bool InstallStubsClassVisitor(mirror::Class* klass, void* arg)
EXCLUSIVE_LOCKS_REQUIRED(Locks::mutator_lock_) {
Instrumentation* instrumentation = reinterpret_cast<Instrumentation*>(arg);
instrumentation->InstallStubsForClass(klass);
return true; // we visit all classes.
}
Instrumentation::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_field_read_listeners_(false), have_field_write_listeners_(false),
have_exception_caught_listeners_(false), have_backward_branch_listeners_(false),
deoptimized_methods_lock_("deoptimized methods lock"),
deoptimization_enabled_(false),
interpreter_handler_table_(kMainHandlerTable),
quick_alloc_entry_points_instrumentation_counter_(0) {
}
void Instrumentation::InstallStubsForClass(mirror::Class* klass) {
if (klass->IsErroneous()) {
// We can't execute code in a erroneous class: do nothing.
} else if (!klass->IsResolved()) {
// We need the class to be resolved to install/uninstall stubs. Otherwise its methods
// could not be initialized or linked with regards to class inheritance.
} else {
for (size_t i = 0, e = klass->NumDirectMethods(); i < e; i++) {
InstallStubsForMethod(klass->GetDirectMethod(i, sizeof(void*)));
}
for (size_t i = 0, e = klass->NumVirtualMethods(); i < e; i++) {
InstallStubsForMethod(klass->GetVirtualMethod(i, sizeof(void*)));
}
}
}
static void UpdateEntrypoints(ArtMethod* method, const void* quick_code)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
Runtime* const runtime = Runtime::Current();
jit::Jit* jit = runtime->GetJit();
if (jit != nullptr) {
const void* old_code_ptr = method->GetEntryPointFromQuickCompiledCode();
jit::JitCodeCache* code_cache = jit->GetCodeCache();
if (code_cache->ContainsCodePtr(old_code_ptr)) {
// Save the old compiled code since we need it to implement ClassLinker::GetQuickOatCodeFor.
code_cache->SaveCompiledCode(method, old_code_ptr);
}
}
method->SetEntryPointFromQuickCompiledCode(quick_code);
if (!method->IsResolutionMethod()) {
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
if (class_linker->IsQuickToInterpreterBridge(quick_code) ||
(class_linker->IsQuickResolutionStub(quick_code) &&
Runtime::Current()->GetInstrumentation()->IsForcedInterpretOnly() &&
!method->IsNative() && !method->IsProxyMethod())) {
DCHECK(!method->IsNative()) << PrettyMethod(method);
DCHECK(!method->IsProxyMethod()) << PrettyMethod(method);
method->SetEntryPointFromInterpreter(art::artInterpreterToInterpreterBridge);
} else {
method->SetEntryPointFromInterpreter(art::artInterpreterToCompiledCodeBridge);
}
}
}
void Instrumentation::InstallStubsForMethod(ArtMethod* method) {
if (method->IsAbstract() || method->IsProxyMethod()) {
// Do not change stubs for these methods.
return;
}
// Don't stub Proxy.<init>. Note that the Proxy class itself is not a proxy class.
if (method->IsConstructor() &&
method->GetDeclaringClass()->DescriptorEquals("Ljava/lang/reflect/Proxy;")) {
return;
}
const void* new_quick_code;
bool uninstall = !entry_exit_stubs_installed_ && !interpreter_stubs_installed_;
Runtime* const runtime = Runtime::Current();
ClassLinker* const class_linker = runtime->GetClassLinker();
bool is_class_initialized = method->GetDeclaringClass()->IsInitialized();
if (uninstall) {
if ((forced_interpret_only_ || IsDeoptimized(method)) && !method->IsNative()) {
new_quick_code = GetQuickToInterpreterBridge();
} else if (is_class_initialized || !method->IsStatic() || method->IsConstructor()) {
new_quick_code = class_linker->GetQuickOatCodeFor(method);
} else {
new_quick_code = GetQuickResolutionStub();
}
} else { // !uninstall
if ((interpreter_stubs_installed_ || forced_interpret_only_ || IsDeoptimized(method)) &&
!method->IsNative()) {
new_quick_code = GetQuickToInterpreterBridge();
} else {
// Do not overwrite resolution trampoline. When the trampoline initializes the method's
// class, all its static methods code will be set to the instrumentation entry point.
// For more details, see ClassLinker::FixupStaticTrampolines.
if (is_class_initialized || !method->IsStatic() || method->IsConstructor()) {
if (entry_exit_stubs_installed_) {
new_quick_code = GetQuickInstrumentationEntryPoint();
} else {
new_quick_code = class_linker->GetQuickOatCodeFor(method);
}
} else {
new_quick_code = GetQuickResolutionStub();
}
}
}
UpdateEntrypoints(method, new_quick_code);
}
// Places the instrumentation exit pc as the return PC for every quick frame. This also allows
// deoptimization of quick frames to interpreter frames.
// Since we may already have done this previously, we need to push new instrumentation frame before
// existing instrumentation frames.
static void InstrumentationInstallStack(Thread* thread, void* arg)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
struct InstallStackVisitor FINAL : public StackVisitor {
InstallStackVisitor(Thread* thread_in, Context* context, uintptr_t instrumentation_exit_pc)
: StackVisitor(thread_in, context, kInstrumentationStackWalk),
instrumentation_stack_(thread_in->GetInstrumentationStack()),
instrumentation_exit_pc_(instrumentation_exit_pc),
reached_existing_instrumentation_frames_(false), instrumentation_stack_depth_(0),
last_return_pc_(0) {
}
bool VisitFrame() OVERRIDE SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
ArtMethod* m = GetMethod();
if (m == nullptr) {
if (kVerboseInstrumentation) {
LOG(INFO) << " Skipping upcall. Frame " << GetFrameId();
}
last_return_pc_ = 0;
return true; // Ignore upcalls.
}
if (GetCurrentQuickFrame() == nullptr) {
bool interpreter_frame = true;
InstrumentationStackFrame instrumentation_frame(GetThisObject(), m, 0, GetFrameId(),
interpreter_frame);
if (kVerboseInstrumentation) {
LOG(INFO) << "Pushing shadow frame " << instrumentation_frame.Dump();
}
shadow_stack_.push_back(instrumentation_frame);
return true; // Continue.
}
uintptr_t return_pc = GetReturnPc();
if (m->IsRuntimeMethod()) {
if (return_pc == instrumentation_exit_pc_) {
if (kVerboseInstrumentation) {
LOG(INFO) << " Handling quick to interpreter transition. Frame " << GetFrameId();
}
CHECK_LT(instrumentation_stack_depth_, instrumentation_stack_->size());
const InstrumentationStackFrame& frame =
instrumentation_stack_->at(instrumentation_stack_depth_);
CHECK(frame.interpreter_entry_);
// This is an interpreter frame so method enter event must have been reported. However we
// need to push a DEX pc into the dex_pcs_ list to match size of instrumentation stack.
// Since we won't report method entry here, we can safely push any DEX pc.
dex_pcs_.push_back(0);
last_return_pc_ = frame.return_pc_;
++instrumentation_stack_depth_;
return true;
} else {
if (kVerboseInstrumentation) {
LOG(INFO) << " Skipping runtime method. Frame " << GetFrameId();
}
last_return_pc_ = GetReturnPc();
return true; // Ignore unresolved methods since they will be instrumented after resolution.
}
}
if (kVerboseInstrumentation) {
LOG(INFO) << " Installing exit stub in " << DescribeLocation();
}
if (return_pc == instrumentation_exit_pc_) {
// We've reached a frame which has already been installed with instrumentation exit stub.
// We should have already installed instrumentation on previous frames.
reached_existing_instrumentation_frames_ = true;
CHECK_LT(instrumentation_stack_depth_, instrumentation_stack_->size());
const InstrumentationStackFrame& frame =
instrumentation_stack_->at(instrumentation_stack_depth_);
CHECK_EQ(m, frame.method_) << "Expected " << PrettyMethod(m)
<< ", Found " << PrettyMethod(frame.method_);
return_pc = frame.return_pc_;
if (kVerboseInstrumentation) {
LOG(INFO) << "Ignoring already instrumented " << frame.Dump();
}
} else {
CHECK_NE(return_pc, 0U);
CHECK(!reached_existing_instrumentation_frames_);
InstrumentationStackFrame instrumentation_frame(GetThisObject(), m, return_pc, GetFrameId(),
false);
if (kVerboseInstrumentation) {
LOG(INFO) << "Pushing frame " << instrumentation_frame.Dump();
}
// Insert frame at the right position so we do not corrupt the instrumentation stack.
// Instrumentation stack frames are in descending frame id order.
auto it = instrumentation_stack_->begin();
for (auto end = instrumentation_stack_->end(); it != end; ++it) {
const InstrumentationStackFrame& current = *it;
if (instrumentation_frame.frame_id_ >= current.frame_id_) {
break;
}
}
instrumentation_stack_->insert(it, instrumentation_frame);
SetReturnPc(instrumentation_exit_pc_);
}
dex_pcs_.push_back(m->ToDexPc(last_return_pc_));
last_return_pc_ = return_pc;
++instrumentation_stack_depth_;
return true; // Continue.
}
std::deque<InstrumentationStackFrame>* const instrumentation_stack_;
std::vector<InstrumentationStackFrame> shadow_stack_;
std::vector<uint32_t> dex_pcs_;
const uintptr_t instrumentation_exit_pc_;
bool reached_existing_instrumentation_frames_;
size_t instrumentation_stack_depth_;
uintptr_t last_return_pc_;
};
if (kVerboseInstrumentation) {
std::string thread_name;
thread->GetThreadName(thread_name);
LOG(INFO) << "Installing exit stubs in " << thread_name;
}
Instrumentation* instrumentation = reinterpret_cast<Instrumentation*>(arg);
std::unique_ptr<Context> context(Context::Create());
uintptr_t instrumentation_exit_pc = reinterpret_cast<uintptr_t>(GetQuickInstrumentationExitPc());
InstallStackVisitor visitor(thread, context.get(), instrumentation_exit_pc);
visitor.WalkStack(true);
CHECK_EQ(visitor.dex_pcs_.size(), thread->GetInstrumentationStack()->size());
if (instrumentation->ShouldNotifyMethodEnterExitEvents()) {
// Create method enter events for all methods currently on the thread's stack. We only do this
// if no debugger is attached to prevent from posting events twice.
auto ssi = visitor.shadow_stack_.rbegin();
for (auto isi = thread->GetInstrumentationStack()->rbegin(),
end = thread->GetInstrumentationStack()->rend(); isi != end; ++isi) {
while (ssi != visitor.shadow_stack_.rend() && (*ssi).frame_id_ < (*isi).frame_id_) {
instrumentation->MethodEnterEvent(thread, (*ssi).this_object_, (*ssi).method_, 0);
++ssi;
}
uint32_t dex_pc = visitor.dex_pcs_.back();
visitor.dex_pcs_.pop_back();
if (!isi->interpreter_entry_) {
instrumentation->MethodEnterEvent(thread, (*isi).this_object_, (*isi).method_, dex_pc);
}
}
}
thread->VerifyStack();
}
// Removes the instrumentation exit pc as the return PC for every quick frame.
static void InstrumentationRestoreStack(Thread* thread, void* arg)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
struct RestoreStackVisitor FINAL : public StackVisitor {
RestoreStackVisitor(Thread* thread_in, uintptr_t instrumentation_exit_pc,
Instrumentation* instrumentation)
: StackVisitor(thread_in, nullptr, kInstrumentationStackWalk),
thread_(thread_in),
instrumentation_exit_pc_(instrumentation_exit_pc),
instrumentation_(instrumentation),
instrumentation_stack_(thread_in->GetInstrumentationStack()),
frames_removed_(0) {}
bool VisitFrame() OVERRIDE SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
if (instrumentation_stack_->size() == 0) {
return false; // Stop.
}
ArtMethod* m = GetMethod();
if (GetCurrentQuickFrame() == nullptr) {
if (kVerboseInstrumentation) {
LOG(INFO) << " Ignoring a shadow frame. Frame " << GetFrameId()
<< " Method=" << PrettyMethod(m);
}
return true; // Ignore shadow frames.
}
if (m == nullptr) {
if (kVerboseInstrumentation) {
LOG(INFO) << " Skipping upcall. Frame " << GetFrameId();
}
return true; // Ignore upcalls.
}
bool removed_stub = false;
// TODO: make this search more efficient?
const size_t frameId = GetFrameId();
for (const InstrumentationStackFrame& instrumentation_frame : *instrumentation_stack_) {
if (instrumentation_frame.frame_id_ == frameId) {
if (kVerboseInstrumentation) {
LOG(INFO) << " Removing exit stub in " << DescribeLocation();
}
if (instrumentation_frame.interpreter_entry_) {
CHECK(m == Runtime::Current()->GetCalleeSaveMethod(Runtime::kRefsAndArgs));
} else {
CHECK(m == instrumentation_frame.method_) << PrettyMethod(m);
}
SetReturnPc(instrumentation_frame.return_pc_);
if (instrumentation_->ShouldNotifyMethodEnterExitEvents()) {
// Create the method exit events. As the methods didn't really exit the result is 0.
// We only do this if no debugger is attached to prevent from posting events twice.
instrumentation_->MethodExitEvent(thread_, instrumentation_frame.this_object_, m,
GetDexPc(), JValue());
}
frames_removed_++;
removed_stub = true;
break;
}
}
if (!removed_stub) {
if (kVerboseInstrumentation) {
LOG(INFO) << " No exit stub in " << DescribeLocation();
}
}
return true; // Continue.
}
Thread* const thread_;
const uintptr_t instrumentation_exit_pc_;
Instrumentation* const instrumentation_;
std::deque<instrumentation::InstrumentationStackFrame>* const instrumentation_stack_;
size_t frames_removed_;
};
if (kVerboseInstrumentation) {
std::string thread_name;
thread->GetThreadName(thread_name);
LOG(INFO) << "Removing exit stubs in " << thread_name;
}
std::deque<instrumentation::InstrumentationStackFrame>* stack = thread->GetInstrumentationStack();
if (stack->size() > 0) {
Instrumentation* instrumentation = reinterpret_cast<Instrumentation*>(arg);
uintptr_t instrumentation_exit_pc =
reinterpret_cast<uintptr_t>(GetQuickInstrumentationExitPc());
RestoreStackVisitor visitor(thread, instrumentation_exit_pc, instrumentation);
visitor.WalkStack(true);
CHECK_EQ(visitor.frames_removed_, stack->size());
while (stack->size() > 0) {
stack->pop_front();
}
}
}
static bool HasEvent(Instrumentation::InstrumentationEvent expected, uint32_t events) {
return (events & expected) != 0;
}
void Instrumentation::AddListener(InstrumentationListener* listener, uint32_t events) {
Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current());
if (HasEvent(kMethodEntered, events)) {
method_entry_listeners_.push_back(listener);
have_method_entry_listeners_ = true;
}
if (HasEvent(kMethodExited, events)) {
method_exit_listeners_.push_back(listener);
have_method_exit_listeners_ = true;
}
if (HasEvent(kMethodUnwind, events)) {
method_unwind_listeners_.push_back(listener);
have_method_unwind_listeners_ = true;
}
if (HasEvent(kBackwardBranch, events)) {
backward_branch_listeners_.push_back(listener);
have_backward_branch_listeners_ = true;
}
if (HasEvent(kDexPcMoved, events)) {
std::list<InstrumentationListener*>* modified;
if (have_dex_pc_listeners_) {
modified = new std::list<InstrumentationListener*>(*dex_pc_listeners_.get());
} else {
modified = new std::list<InstrumentationListener*>();
}
modified->push_back(listener);
dex_pc_listeners_.reset(modified);
have_dex_pc_listeners_ = true;
}
if (HasEvent(kFieldRead, events)) {
std::list<InstrumentationListener*>* modified;
if (have_field_read_listeners_) {
modified = new std::list<InstrumentationListener*>(*field_read_listeners_.get());
} else {
modified = new std::list<InstrumentationListener*>();
}
modified->push_back(listener);
field_read_listeners_.reset(modified);
have_field_read_listeners_ = true;
}
if (HasEvent(kFieldWritten, events)) {
std::list<InstrumentationListener*>* modified;
if (have_field_write_listeners_) {
modified = new std::list<InstrumentationListener*>(*field_write_listeners_.get());
} else {
modified = new std::list<InstrumentationListener*>();
}
modified->push_back(listener);
field_write_listeners_.reset(modified);
have_field_write_listeners_ = true;
}
if (HasEvent(kExceptionCaught, events)) {
std::list<InstrumentationListener*>* modified;
if (have_exception_caught_listeners_) {
modified = new std::list<InstrumentationListener*>(*exception_caught_listeners_.get());
} else {
modified = new std::list<InstrumentationListener*>();
}
modified->push_back(listener);
exception_caught_listeners_.reset(modified);
have_exception_caught_listeners_ = true;
}
UpdateInterpreterHandlerTable();
}
void Instrumentation::RemoveListener(InstrumentationListener* listener, uint32_t events) {
Locks::mutator_lock_->AssertExclusiveHeld(Thread::Current());
if (HasEvent(kMethodEntered, events) && have_method_entry_listeners_) {
method_entry_listeners_.remove(listener);
have_method_entry_listeners_ = !method_entry_listeners_.empty();
}
if (HasEvent(kMethodExited, events) && have_method_exit_listeners_) {
method_exit_listeners_.remove(listener);
have_method_exit_listeners_ = !method_exit_listeners_.empty();
}
if (HasEvent(kMethodUnwind, events) && have_method_unwind_listeners_) {
method_unwind_listeners_.remove(listener);
have_method_unwind_listeners_ = !method_unwind_listeners_.empty();
}
if (HasEvent(kBackwardBranch, events) && have_backward_branch_listeners_) {
backward_branch_listeners_.remove(listener);
have_backward_branch_listeners_ = !backward_branch_listeners_.empty();
}
if (HasEvent(kDexPcMoved, events) && have_dex_pc_listeners_) {
std::list<InstrumentationListener*>* modified =
new std::list<InstrumentationListener*>(*dex_pc_listeners_.get());
modified->remove(listener);
have_dex_pc_listeners_ = !modified->empty();
if (have_dex_pc_listeners_) {
dex_pc_listeners_.reset(modified);
} else {
dex_pc_listeners_.reset();
delete modified;
}
}
if (HasEvent(kFieldRead, events) && have_field_read_listeners_) {
std::list<InstrumentationListener*>* modified =
new std::list<InstrumentationListener*>(*field_read_listeners_.get());
modified->remove(listener);
have_field_read_listeners_ = !modified->empty();
if (have_field_read_listeners_) {
field_read_listeners_.reset(modified);
} else {
field_read_listeners_.reset();
delete modified;
}
}
if (HasEvent(kFieldWritten, events) && have_field_write_listeners_) {
std::list<InstrumentationListener*>* modified =
new std::list<InstrumentationListener*>(*field_write_listeners_.get());
modified->remove(listener);
have_field_write_listeners_ = !modified->empty();
if (have_field_write_listeners_) {
field_write_listeners_.reset(modified);
} else {
field_write_listeners_.reset();
delete modified;
}
}
if (HasEvent(kExceptionCaught, events) && have_exception_caught_listeners_) {
std::list<InstrumentationListener*>* modified =
new std::list<InstrumentationListener*>(*exception_caught_listeners_.get());
modified->remove(listener);
have_exception_caught_listeners_ = !modified->empty();
if (have_exception_caught_listeners_) {
exception_caught_listeners_.reset(modified);
} else {
exception_caught_listeners_.reset();
delete modified;
}
}
UpdateInterpreterHandlerTable();
}
Instrumentation::InstrumentationLevel Instrumentation::GetCurrentInstrumentationLevel() const {
if (interpreter_stubs_installed_) {
return InstrumentationLevel::kInstrumentWithInterpreter;
} else if (entry_exit_stubs_installed_) {
return InstrumentationLevel::kInstrumentWithInstrumentationStubs;
} else {
return InstrumentationLevel::kInstrumentNothing;
}
}
void Instrumentation::ConfigureStubs(const char* key, InstrumentationLevel desired_level) {
// Store the instrumentation level for this key or remove it.
if (desired_level == InstrumentationLevel::kInstrumentNothing) {
// The client no longer needs instrumentation.
requested_instrumentation_levels_.erase(key);
} else {
// The client needs instrumentation.
requested_instrumentation_levels_.Overwrite(key, desired_level);
}
// Look for the highest required instrumentation level.
InstrumentationLevel requested_level = InstrumentationLevel::kInstrumentNothing;
for (const auto& v : requested_instrumentation_levels_) {
requested_level = std::max(requested_level, v.second);
}
interpret_only_ = (requested_level == InstrumentationLevel::kInstrumentWithInterpreter) ||
forced_interpret_only_;
InstrumentationLevel current_level = GetCurrentInstrumentationLevel();
if (requested_level == current_level) {
// We're already set.
return;
}
Thread* const self = Thread::Current();
Runtime* runtime = Runtime::Current();
Locks::mutator_lock_->AssertExclusiveHeld(self);
Locks::thread_list_lock_->AssertNotHeld(self);
if (requested_level > InstrumentationLevel::kInstrumentNothing) {
if (requested_level == InstrumentationLevel::kInstrumentWithInterpreter) {
interpreter_stubs_installed_ = true;
entry_exit_stubs_installed_ = true;
} else {
CHECK_EQ(requested_level, InstrumentationLevel::kInstrumentWithInstrumentationStubs);
entry_exit_stubs_installed_ = true;
interpreter_stubs_installed_ = false;
}
runtime->GetClassLinker()->VisitClasses(InstallStubsClassVisitor, this);
instrumentation_stubs_installed_ = true;
MutexLock mu(self, *Locks::thread_list_lock_);
runtime->GetThreadList()->ForEach(InstrumentationInstallStack, this);
} else {
interpreter_stubs_installed_ = false;
entry_exit_stubs_installed_ = false;
runtime->GetClassLinker()->VisitClasses(InstallStubsClassVisitor, this);
// Restore stack only if there is no method currently deoptimized.
bool empty;
{
ReaderMutexLock mu(self, deoptimized_methods_lock_);
empty = IsDeoptimizedMethodsEmpty(); // Avoid lock violation.
}
if (empty) {
instrumentation_stubs_installed_ = false;
MutexLock mu(self, *Locks::thread_list_lock_);
Runtime::Current()->GetThreadList()->ForEach(InstrumentationRestoreStack, this);
}
}
}
static void ResetQuickAllocEntryPointsForThread(Thread* thread, void* arg ATTRIBUTE_UNUSED) {
thread->ResetQuickAllocEntryPointsForThread();
}
void Instrumentation::SetEntrypointsInstrumented(bool instrumented) {
Thread* self = Thread::Current();
Runtime* runtime = Runtime::Current();
ThreadList* tl = runtime->GetThreadList();
Locks::mutator_lock_->AssertNotHeld(self);
Locks::instrument_entrypoints_lock_->AssertHeld(self);
if (runtime->IsStarted()) {
tl->SuspendAll(__FUNCTION__);
}
{
MutexLock mu(self, *Locks::runtime_shutdown_lock_);
SetQuickAllocEntryPointsInstrumented(instrumented);
ResetQuickAllocEntryPoints();
}
if (runtime->IsStarted()) {
tl->ResumeAll();
}
}
void Instrumentation::InstrumentQuickAllocEntryPoints() {
MutexLock mu(Thread::Current(), *Locks::instrument_entrypoints_lock_);
InstrumentQuickAllocEntryPointsLocked();
}
void Instrumentation::UninstrumentQuickAllocEntryPoints() {
MutexLock mu(Thread::Current(), *Locks::instrument_entrypoints_lock_);
UninstrumentQuickAllocEntryPointsLocked();
}
void Instrumentation::InstrumentQuickAllocEntryPointsLocked() {
Locks::instrument_entrypoints_lock_->AssertHeld(Thread::Current());
if (quick_alloc_entry_points_instrumentation_counter_ == 0) {
SetEntrypointsInstrumented(true);
}
++quick_alloc_entry_points_instrumentation_counter_;
}
void Instrumentation::UninstrumentQuickAllocEntryPointsLocked() {
Locks::instrument_entrypoints_lock_->AssertHeld(Thread::Current());
CHECK_GT(quick_alloc_entry_points_instrumentation_counter_, 0U);
--quick_alloc_entry_points_instrumentation_counter_;
if (quick_alloc_entry_points_instrumentation_counter_ == 0) {
SetEntrypointsInstrumented(false);
}
}
void Instrumentation::ResetQuickAllocEntryPoints() {
Runtime* runtime = Runtime::Current();
if (runtime->IsStarted()) {
MutexLock mu(Thread::Current(), *Locks::thread_list_lock_);
runtime->GetThreadList()->ForEach(ResetQuickAllocEntryPointsForThread, nullptr);
}
}
void Instrumentation::UpdateMethodsCode(ArtMethod* method, const void* quick_code) {
DCHECK(method->GetDeclaringClass()->IsResolved());
const void* new_quick_code;
if (LIKELY(!instrumentation_stubs_installed_)) {
new_quick_code = quick_code;
} else {
if ((interpreter_stubs_installed_ || IsDeoptimized(method)) && !method->IsNative()) {
new_quick_code = GetQuickToInterpreterBridge();
} else {
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
if (class_linker->IsQuickResolutionStub(quick_code) ||
class_linker->IsQuickToInterpreterBridge(quick_code)) {
new_quick_code = quick_code;
} else if (entry_exit_stubs_installed_) {
new_quick_code = GetQuickInstrumentationEntryPoint();
} else {
new_quick_code = quick_code;
}
}
}
UpdateEntrypoints(method, new_quick_code);
}
bool Instrumentation::AddDeoptimizedMethod(ArtMethod* method) {
if (IsDeoptimizedMethod(method)) {
// Already in the map. Return.
return false;
}
// Not found. Add it.
deoptimized_methods_.insert(method);
return true;
}
bool Instrumentation::IsDeoptimizedMethod(ArtMethod* method) {
return deoptimized_methods_.find(method) != deoptimized_methods_.end();
}
ArtMethod* Instrumentation::BeginDeoptimizedMethod() {
if (deoptimized_methods_.empty()) {
// Empty.
return nullptr;
}
return *deoptimized_methods_.begin();
}
bool Instrumentation::RemoveDeoptimizedMethod(ArtMethod* method) {
auto it = deoptimized_methods_.find(method);
if (it == deoptimized_methods_.end()) {
return false;
}
deoptimized_methods_.erase(it);
return true;
}
bool Instrumentation::IsDeoptimizedMethodsEmpty() const {
return deoptimized_methods_.empty();
}
void Instrumentation::Deoptimize(ArtMethod* method) {
CHECK(!method->IsNative());
CHECK(!method->IsProxyMethod());
CHECK(!method->IsAbstract());
Thread* self = Thread::Current();
{
WriterMutexLock mu(self, deoptimized_methods_lock_);
bool has_not_been_deoptimized = AddDeoptimizedMethod(method);
CHECK(has_not_been_deoptimized) << "Method " << PrettyMethod(method)
<< " is already deoptimized";
}
if (!interpreter_stubs_installed_) {
UpdateEntrypoints(method, GetQuickInstrumentationEntryPoint());
// Install instrumentation exit stub and instrumentation frames. We may already have installed
// these previously so it will only cover the newly created frames.
instrumentation_stubs_installed_ = true;
MutexLock mu(self, *Locks::thread_list_lock_);
Runtime::Current()->GetThreadList()->ForEach(InstrumentationInstallStack, this);
}
}
void Instrumentation::Undeoptimize(ArtMethod* method) {
CHECK(!method->IsNative());
CHECK(!method->IsProxyMethod());
CHECK(!method->IsAbstract());
Thread* self = Thread::Current();
bool empty;
{
WriterMutexLock mu(self, deoptimized_methods_lock_);
bool found_and_erased = RemoveDeoptimizedMethod(method);
CHECK(found_and_erased) << "Method " << PrettyMethod(method)
<< " is not deoptimized";
empty = IsDeoptimizedMethodsEmpty();
}
// Restore code and possibly stack only if we did not deoptimize everything.
if (!interpreter_stubs_installed_) {
// Restore its code or resolution trampoline.
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
if (method->IsStatic() && !method->IsConstructor() &&
!method->GetDeclaringClass()->IsInitialized()) {
UpdateEntrypoints(method, GetQuickResolutionStub());
} else {
const void* quick_code = class_linker->GetQuickOatCodeFor(method);
UpdateEntrypoints(method, quick_code);
}
// If there is no deoptimized method left, we can restore the stack of each thread.
if (empty) {
MutexLock mu(self, *Locks::thread_list_lock_);
Runtime::Current()->GetThreadList()->ForEach(InstrumentationRestoreStack, this);
instrumentation_stubs_installed_ = false;
}
}
}
bool Instrumentation::IsDeoptimized(ArtMethod* method) {
DCHECK(method != nullptr);
ReaderMutexLock mu(Thread::Current(), deoptimized_methods_lock_);
return IsDeoptimizedMethod(method);
}
void Instrumentation::EnableDeoptimization() {
ReaderMutexLock mu(Thread::Current(), deoptimized_methods_lock_);
CHECK(IsDeoptimizedMethodsEmpty());
CHECK_EQ(deoptimization_enabled_, false);
deoptimization_enabled_ = true;
}
void Instrumentation::DisableDeoptimization(const char* key) {
CHECK_EQ(deoptimization_enabled_, true);
// If we deoptimized everything, undo it.
if (interpreter_stubs_installed_) {
UndeoptimizeEverything(key);
}
// Undeoptimized selected methods.
while (true) {
ArtMethod* method;
{
ReaderMutexLock mu(Thread::Current(), deoptimized_methods_lock_);
if (IsDeoptimizedMethodsEmpty()) {
break;
}
method = BeginDeoptimizedMethod();
CHECK(method != nullptr);
}
Undeoptimize(method);
}
deoptimization_enabled_ = false;
}
// Indicates if instrumentation should notify method enter/exit events to the listeners.
bool Instrumentation::ShouldNotifyMethodEnterExitEvents() const {
if (!HasMethodEntryListeners() && !HasMethodExitListeners()) {
return false;
}
return !deoptimization_enabled_ && !interpreter_stubs_installed_;
}
void Instrumentation::DeoptimizeEverything(const char* key) {
CHECK(deoptimization_enabled_);
ConfigureStubs(key, InstrumentationLevel::kInstrumentWithInterpreter);
}
void Instrumentation::UndeoptimizeEverything(const char* key) {
CHECK(interpreter_stubs_installed_);
CHECK(deoptimization_enabled_);
ConfigureStubs(key, InstrumentationLevel::kInstrumentNothing);
}
void Instrumentation::EnableMethodTracing(const char* key, bool needs_interpreter) {
InstrumentationLevel level;
if (needs_interpreter) {
level = InstrumentationLevel::kInstrumentWithInterpreter;
} else {
level = InstrumentationLevel::kInstrumentWithInstrumentationStubs;
}
ConfigureStubs(key, level);
}
void Instrumentation::DisableMethodTracing(const char* key) {
ConfigureStubs(key, InstrumentationLevel::kInstrumentNothing);
}
const void* Instrumentation::GetQuickCodeFor(ArtMethod* method, size_t pointer_size) const {
Runtime* runtime = Runtime::Current();
if (LIKELY(!instrumentation_stubs_installed_)) {
const void* code = method->GetEntryPointFromQuickCompiledCodePtrSize(pointer_size);
DCHECK(code != nullptr);
ClassLinker* class_linker = runtime->GetClassLinker();
if (LIKELY(!class_linker->IsQuickResolutionStub(code) &&
!class_linker->IsQuickToInterpreterBridge(code)) &&
!class_linker->IsQuickResolutionStub(code) &&
!class_linker->IsQuickToInterpreterBridge(code)) {
return code;
}
}
return runtime->GetClassLinker()->GetQuickOatCodeFor(method);
}
void Instrumentation::MethodEnterEventImpl(Thread* thread, mirror::Object* this_object,
ArtMethod* method,
uint32_t dex_pc) const {
auto it = method_entry_listeners_.begin();
bool is_end = (it == method_entry_listeners_.end());
// Implemented this way to prevent problems caused by modification of the list while iterating.
while (!is_end) {
InstrumentationListener* cur = *it;
++it;
is_end = (it == method_entry_listeners_.end());
cur->MethodEntered(thread, this_object, method, dex_pc);
}
}
void Instrumentation::MethodExitEventImpl(Thread* thread, mirror::Object* this_object,
ArtMethod* method,
uint32_t dex_pc, const JValue& return_value) const {
auto it = method_exit_listeners_.begin();
bool is_end = (it == method_exit_listeners_.end());
// Implemented this way to prevent problems caused by modification of the list while iterating.
while (!is_end) {
InstrumentationListener* cur = *it;
++it;
is_end = (it == method_exit_listeners_.end());
cur->MethodExited(thread, this_object, method, dex_pc, return_value);
}
}
void Instrumentation::MethodUnwindEvent(Thread* thread, mirror::Object* this_object,
ArtMethod* method,
uint32_t dex_pc) const {
if (HasMethodUnwindListeners()) {
for (InstrumentationListener* listener : method_unwind_listeners_) {
listener->MethodUnwind(thread, this_object, method, dex_pc);
}
}
}
void Instrumentation::DexPcMovedEventImpl(Thread* thread, mirror::Object* this_object,
ArtMethod* method,
uint32_t dex_pc) const {
std::shared_ptr<std::list<InstrumentationListener*>> original(dex_pc_listeners_);
for (InstrumentationListener* listener : *original.get()) {
listener->DexPcMoved(thread, this_object, method, dex_pc);
}
}
void Instrumentation::BackwardBranchImpl(Thread* thread, ArtMethod* method,
int32_t offset) const {
for (InstrumentationListener* listener : backward_branch_listeners_) {
listener->BackwardBranch(thread, method, offset);
}
}
void Instrumentation::FieldReadEventImpl(Thread* thread, mirror::Object* this_object,
ArtMethod* method, uint32_t dex_pc,
ArtField* field) const {
std::shared_ptr<std::list<InstrumentationListener*>> original(field_read_listeners_);
for (InstrumentationListener* listener : *original.get()) {
listener->FieldRead(thread, this_object, method, dex_pc, field);
}
}
void Instrumentation::FieldWriteEventImpl(Thread* thread, mirror::Object* this_object,
ArtMethod* method, uint32_t dex_pc,
ArtField* field, const JValue& field_value) const {
std::shared_ptr<std::list<InstrumentationListener*>> original(field_write_listeners_);
for (InstrumentationListener* listener : *original.get()) {
listener->FieldWritten(thread, this_object, method, dex_pc, field, field_value);
}
}
void Instrumentation::ExceptionCaughtEvent(Thread* thread,
mirror::Throwable* exception_object) const {
if (HasExceptionCaughtListeners()) {
DCHECK_EQ(thread->GetException(), exception_object);
thread->ClearException();
std::shared_ptr<std::list<InstrumentationListener*>> original(exception_caught_listeners_);
for (InstrumentationListener* listener : *original.get()) {
listener->ExceptionCaught(thread, exception_object);
}
thread->SetException(exception_object);
}
}
static void CheckStackDepth(Thread* self, const InstrumentationStackFrame& instrumentation_frame,
int delta)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
size_t frame_id = StackVisitor::ComputeNumFrames(self, kInstrumentationStackWalk) + delta;
if (frame_id != instrumentation_frame.frame_id_) {
LOG(ERROR) << "Expected frame_id=" << frame_id << " but found "
<< instrumentation_frame.frame_id_;
StackVisitor::DescribeStack(self);
CHECK_EQ(frame_id, instrumentation_frame.frame_id_);
}
}
void Instrumentation::PushInstrumentationStackFrame(Thread* self, mirror::Object* this_object,
ArtMethod* method,
uintptr_t lr, bool interpreter_entry) {
// We have a callee-save frame meaning this value is guaranteed to never be 0.
size_t frame_id = StackVisitor::ComputeNumFrames(self, kInstrumentationStackWalk);
std::deque<instrumentation::InstrumentationStackFrame>* stack = self->GetInstrumentationStack();
if (kVerboseInstrumentation) {
LOG(INFO) << "Entering " << PrettyMethod(method) << " from PC " << reinterpret_cast<void*>(lr);
}
instrumentation::InstrumentationStackFrame instrumentation_frame(this_object, method, lr,
frame_id, interpreter_entry);
stack->push_front(instrumentation_frame);
if (!interpreter_entry) {
MethodEnterEvent(self, this_object, method, 0);
}
}
TwoWordReturn Instrumentation::PopInstrumentationStackFrame(Thread* self, uintptr_t* return_pc,
uint64_t gpr_result,
uint64_t fpr_result) {
// Do the pop.
std::deque<instrumentation::InstrumentationStackFrame>* stack = self->GetInstrumentationStack();
CHECK_GT(stack->size(), 0U);
InstrumentationStackFrame instrumentation_frame = stack->front();
stack->pop_front();
// Set return PC and check the sanity of the stack.
*return_pc = instrumentation_frame.return_pc_;
CheckStackDepth(self, instrumentation_frame, 0);
self->VerifyStack();
ArtMethod* method = instrumentation_frame.method_;
uint32_t length;
char return_shorty = method->GetShorty(&length)[0];
JValue return_value;
if (return_shorty == 'V') {
return_value.SetJ(0);
} else if (return_shorty == 'F' || return_shorty == 'D') {
return_value.SetJ(fpr_result);
} else {
return_value.SetJ(gpr_result);
}
// TODO: improve the dex pc information here, requires knowledge of current PC as opposed to
// return_pc.
uint32_t dex_pc = DexFile::kDexNoIndex;
mirror::Object* this_object = instrumentation_frame.this_object_;
if (!instrumentation_frame.interpreter_entry_) {
MethodExitEvent(self, this_object, instrumentation_frame.method_, dex_pc, return_value);
}
// Deoptimize if the caller needs to continue execution in the interpreter. Do nothing if we get
// back to an upcall.
NthCallerVisitor visitor(self, 1, true);
visitor.WalkStack(true);
bool deoptimize = (visitor.caller != nullptr) &&
(interpreter_stubs_installed_ || IsDeoptimized(visitor.caller) ||
Dbg::IsForcedInterpreterNeededForUpcall(self, visitor.caller));
if (deoptimize) {
if (kVerboseInstrumentation) {
LOG(INFO) << StringPrintf("Deoptimizing %s by returning from %s with result %#" PRIx64 " in ",
PrettyMethod(visitor.caller).c_str(),
PrettyMethod(method).c_str(),
return_value.GetJ()) << *self;
}
self->SetDeoptimizationReturnValue(return_value, return_shorty == 'L');
return GetTwoWordSuccessValue(*return_pc,
reinterpret_cast<uintptr_t>(GetQuickDeoptimizationEntryPoint()));
} else {
if (kVerboseInstrumentation) {
LOG(INFO) << "Returning from " << PrettyMethod(method)
<< " to PC " << reinterpret_cast<void*>(*return_pc);
}
return GetTwoWordSuccessValue(0, *return_pc);
}
}
void Instrumentation::PopMethodForUnwind(Thread* self, bool is_deoptimization) const {
// Do the pop.
std::deque<instrumentation::InstrumentationStackFrame>* stack = self->GetInstrumentationStack();
CHECK_GT(stack->size(), 0U);
InstrumentationStackFrame instrumentation_frame = stack->front();
// TODO: bring back CheckStackDepth(self, instrumentation_frame, 2);
stack->pop_front();
ArtMethod* method = instrumentation_frame.method_;
if (is_deoptimization) {
if (kVerboseInstrumentation) {
LOG(INFO) << "Popping for deoptimization " << PrettyMethod(method);
}
} else {
if (kVerboseInstrumentation) {
LOG(INFO) << "Popping for unwind " << PrettyMethod(method);
}
// Notify listeners of method unwind.
// TODO: improve the dex pc information here, requires knowledge of current PC as opposed to
// return_pc.
uint32_t dex_pc = DexFile::kDexNoIndex;
MethodUnwindEvent(self, instrumentation_frame.this_object_, method, dex_pc);
}
}
std::string InstrumentationStackFrame::Dump() const {
std::ostringstream os;
os << "Frame " << frame_id_ << " " << PrettyMethod(method_) << ":"
<< reinterpret_cast<void*>(return_pc_) << " this=" << reinterpret_cast<void*>(this_object_);
return os.str();
}
} // namespace instrumentation
} // namespace art