/* Copyright (C) 2017 The Android Open Source Project
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This file implements interfaces from the file jvmti.h. This implementation
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* is licensed under the same terms as the file jvmti.h. The
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* copyright and license information for the file jvmti.h follows.
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*
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* Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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#include <functional>
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#include <iosfwd>
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#include <mutex>
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#include "deopt_manager.h"
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#include "art_jvmti.h"
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#include "art_method-inl.h"
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#include "base/enums.h"
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#include "base/mutex-inl.h"
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#include "dex/dex_file_annotations.h"
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#include "dex/modifiers.h"
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#include "events-inl.h"
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#include "gc/collector_type.h"
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#include "gc/heap.h"
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#include "gc/scoped_gc_critical_section.h"
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#include "instrumentation.h"
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#include "jit/jit.h"
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#include "jni/jni_internal.h"
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#include "mirror/class-inl.h"
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#include "mirror/object_array-inl.h"
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#include "nativehelper/scoped_local_ref.h"
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#include "read_barrier_config.h"
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#include "runtime_callbacks.h"
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#include "scoped_thread_state_change-inl.h"
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#include "scoped_thread_state_change.h"
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#include "thread-current-inl.h"
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#include "thread_list.h"
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#include "ti_phase.h"
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namespace openjdkjvmti {
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// TODO We should make this much more selective in the future so we only return true when we
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// actually care about the method at this time (ie active frames had locals changed). For now we
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// just assume that if anything has changed any frame's locals we care about all methods. If nothing
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// has we only care about methods with active breakpoints on them. In the future we should probably
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// rewrite all of this to instead do this at the ShadowFrame or thread granularity.
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bool JvmtiMethodInspectionCallback::IsMethodBeingInspected(art::ArtMethod* method) {
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// Non-java-debuggable runtimes we need to assume that any method might not be debuggable and
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// therefore potentially being inspected (due to inlines). If we are debuggable we rely hard on
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// inlining not being done since we don't keep track of which methods get inlined where and simply
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// look to see if the method is breakpointed.
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return !art::Runtime::Current()->IsJavaDebuggable() ||
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manager_->HaveLocalsChanged() ||
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manager_->MethodHasBreakpoints(method);
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}
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bool JvmtiMethodInspectionCallback::IsMethodSafeToJit(art::ArtMethod* method) {
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return !manager_->MethodHasBreakpoints(method);
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}
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bool JvmtiMethodInspectionCallback::MethodNeedsDebugVersion(
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art::ArtMethod* method ATTRIBUTE_UNUSED) {
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return true;
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}
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DeoptManager::DeoptManager()
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: deoptimization_status_lock_("JVMTI_DeoptimizationStatusLock",
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static_cast<art::LockLevel>(
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art::LockLevel::kClassLinkerClassesLock + 1)),
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deoptimization_condition_("JVMTI_DeoptimizationCondition", deoptimization_status_lock_),
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performing_deoptimization_(false),
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global_deopt_count_(0),
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deopter_count_(0),
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breakpoint_status_lock_("JVMTI_BreakpointStatusLock",
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static_cast<art::LockLevel>(art::LockLevel::kAbortLock + 1)),
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inspection_callback_(this),
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set_local_variable_called_(false) { }
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void DeoptManager::Setup() {
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art::ScopedThreadStateChange stsc(art::Thread::Current(),
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art::ThreadState::kWaitingForDebuggerToAttach);
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art::ScopedSuspendAll ssa("Add method Inspection Callback");
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art::RuntimeCallbacks* callbacks = art::Runtime::Current()->GetRuntimeCallbacks();
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callbacks->AddMethodInspectionCallback(&inspection_callback_);
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}
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void DeoptManager::Shutdown() {
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art::ScopedThreadStateChange stsc(art::Thread::Current(),
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art::ThreadState::kWaitingForDebuggerToAttach);
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art::ScopedSuspendAll ssa("remove method Inspection Callback");
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art::RuntimeCallbacks* callbacks = art::Runtime::Current()->GetRuntimeCallbacks();
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callbacks->RemoveMethodInspectionCallback(&inspection_callback_);
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}
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void DeoptManager::DumpDeoptInfo(art::Thread* self, std::ostream& stream) {
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art::ScopedObjectAccess soa(self);
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art::MutexLock mutll(self, *art::Locks::thread_list_lock_);
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art::MutexLock mudsl(self, deoptimization_status_lock_);
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art::MutexLock mubsl(self, breakpoint_status_lock_);
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stream << "Deoptimizer count: " << deopter_count_ << "\n";
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stream << "Global deopt count: " << global_deopt_count_ << "\n";
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stream << "Can perform OSR: " << !set_local_variable_called_.load() << "\n";
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for (const auto& [bp, loc] : this->breakpoint_status_) {
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stream << "Breakpoint: " << bp->PrettyMethod() << " @ 0x" << std::hex << loc << "\n";
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}
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struct DumpThreadDeoptCount : public art::Closure {
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public:
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DumpThreadDeoptCount(std::ostream& stream, std::mutex& mu)
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: cnt_(0), stream_(stream), mu_(mu) {}
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void Run(art::Thread* self) override {
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{
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std::lock_guard<std::mutex> lg(mu_);
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std::string name;
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self->GetThreadName(name);
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stream_ << "Thread " << name << " (id: " << std::dec << self->GetThreadId()
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<< ") force interpreter count " << self->ForceInterpreterCount() << "\n";
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}
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// Increment this after unlocking the mutex so we won't race its destructor.
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cnt_++;
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}
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void WaitForCount(size_t threads) {
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while (cnt_.load() != threads) {
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sched_yield();
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}
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}
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private:
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std::atomic<size_t> cnt_;
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std::ostream& stream_;
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std::mutex& mu_;
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};
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std::mutex mu;
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DumpThreadDeoptCount dtdc(stream, mu);
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auto func = [](art::Thread* thread, void* ctx) {
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reinterpret_cast<DumpThreadDeoptCount*>(ctx)->Run(thread);
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};
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art::Runtime::Current()->GetThreadList()->ForEach(func, &dtdc);
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}
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void DeoptManager::FinishSetup() {
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art::Thread* self = art::Thread::Current();
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art::MutexLock mu(self, deoptimization_status_lock_);
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art::Runtime* runtime = art::Runtime::Current();
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// See if we need to do anything.
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if (!runtime->IsJavaDebuggable()) {
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// See if we can enable all JVMTI functions. If this is false, only kArtTiVersion agents can be
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// retrieved and they will all be best-effort.
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if (PhaseUtil::GetPhaseUnchecked() == JVMTI_PHASE_ONLOAD) {
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// We are still early enough to change the compiler options and get full JVMTI support.
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LOG(INFO) << "Openjdkjvmti plugin loaded on a non-debuggable runtime. Changing runtime to "
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<< "debuggable state. Please pass '--debuggable' to dex2oat and "
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<< "'-Xcompiler-option --debuggable' to dalvikvm in the future.";
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DCHECK(runtime->GetJit() == nullptr) << "Jit should not be running yet!";
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runtime->AddCompilerOption("--debuggable");
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runtime->SetJavaDebuggable(true);
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} else {
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LOG(WARNING) << "Openjdkjvmti plugin was loaded on a non-debuggable Runtime. Plugin was "
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<< "loaded too late to change runtime state to DEBUGGABLE. Only kArtTiVersion "
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<< "(0x" << std::hex << kArtTiVersion << ") environments are available. Some "
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<< "functionality might not work properly.";
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if (runtime->GetJit() == nullptr &&
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runtime->GetJITOptions()->UseJitCompilation() &&
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!runtime->GetInstrumentation()->IsForcedInterpretOnly()) {
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// If we don't have a jit we should try to start the jit for performance reasons. We only
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// need to do this for late attach on non-debuggable processes because for debuggable
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// processes we already rely on jit and we cannot force this jit to start if we are still in
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// OnLoad since the runtime hasn't started up sufficiently. This is only expected to happen
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// on userdebug/eng builds.
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LOG(INFO) << "Attempting to start jit for openjdkjvmti plugin.";
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// Note: use rwx allowed = true, because if this is the system server, we will not be
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// allowed to allocate any JIT code cache, anyways.
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runtime->CreateJitCodeCache(/*rwx_memory_allowed=*/true);
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runtime->CreateJit();
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if (runtime->GetJit() == nullptr) {
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LOG(WARNING) << "Could not start jit for openjdkjvmti plugin. This process might be "
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<< "quite slow as it is running entirely in the interpreter. Try running "
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<< "'setenforce 0' and restarting this process.";
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}
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}
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}
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runtime->DeoptimizeBootImage();
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}
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}
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bool DeoptManager::MethodHasBreakpoints(art::ArtMethod* method) {
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art::MutexLock lk(art::Thread::Current(), breakpoint_status_lock_);
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return MethodHasBreakpointsLocked(method);
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}
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bool DeoptManager::MethodHasBreakpointsLocked(art::ArtMethod* method) {
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auto elem = breakpoint_status_.find(method);
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return elem != breakpoint_status_.end() && elem->second != 0;
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}
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void DeoptManager::RemoveDeoptimizeAllMethods() {
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art::Thread* self = art::Thread::Current();
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art::ScopedThreadSuspension sts(self, art::kSuspended);
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deoptimization_status_lock_.ExclusiveLock(self);
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RemoveDeoptimizeAllMethodsLocked(self);
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}
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void DeoptManager::AddDeoptimizeAllMethods() {
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art::Thread* self = art::Thread::Current();
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art::ScopedThreadSuspension sts(self, art::kSuspended);
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deoptimization_status_lock_.ExclusiveLock(self);
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AddDeoptimizeAllMethodsLocked(self);
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}
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void DeoptManager::AddMethodBreakpoint(art::ArtMethod* method) {
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DCHECK(method->IsInvokable());
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DCHECK(!method->IsProxyMethod()) << method->PrettyMethod();
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DCHECK(!method->IsNative()) << method->PrettyMethod();
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art::Thread* self = art::Thread::Current();
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method = method->GetCanonicalMethod();
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bool is_default = method->IsDefault();
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art::ScopedThreadSuspension sts(self, art::kSuspended);
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deoptimization_status_lock_.ExclusiveLock(self);
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{
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breakpoint_status_lock_.ExclusiveLock(self);
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DCHECK_GT(deopter_count_, 0u) << "unexpected deotpimization request";
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if (MethodHasBreakpointsLocked(method)) {
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// Don't need to do anything extra.
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breakpoint_status_[method]++;
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// Another thread might be deoptimizing the very method we just added new breakpoints for.
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// Wait for any deopts to finish before moving on.
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breakpoint_status_lock_.ExclusiveUnlock(self);
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WaitForDeoptimizationToFinish(self);
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return;
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}
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breakpoint_status_[method] = 1;
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breakpoint_status_lock_.ExclusiveUnlock(self);
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}
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auto instrumentation = art::Runtime::Current()->GetInstrumentation();
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if (instrumentation->IsForcedInterpretOnly()) {
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// We are already interpreting everything so no need to do anything.
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deoptimization_status_lock_.ExclusiveUnlock(self);
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return;
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} else if (is_default) {
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AddDeoptimizeAllMethodsLocked(self);
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} else {
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PerformLimitedDeoptimization(self, method);
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}
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}
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void DeoptManager::RemoveMethodBreakpoint(art::ArtMethod* method) {
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DCHECK(method->IsInvokable()) << method->PrettyMethod();
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DCHECK(!method->IsProxyMethod()) << method->PrettyMethod();
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DCHECK(!method->IsNative()) << method->PrettyMethod();
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art::Thread* self = art::Thread::Current();
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method = method->GetCanonicalMethod();
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bool is_default = method->IsDefault();
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art::ScopedThreadSuspension sts(self, art::kSuspended);
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// Ideally we should do a ScopedSuspendAll right here to get the full mutator_lock_ that we might
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// need but since that is very heavy we will instead just use a condition variable to make sure we
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// don't race with ourselves.
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deoptimization_status_lock_.ExclusiveLock(self);
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bool is_last_breakpoint;
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{
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art::MutexLock mu(self, breakpoint_status_lock_);
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DCHECK_GT(deopter_count_, 0u) << "unexpected deotpimization request";
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DCHECK(MethodHasBreakpointsLocked(method)) << "Breakpoint on a method was removed without "
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<< "breakpoints present!";
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breakpoint_status_[method] -= 1;
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is_last_breakpoint = (breakpoint_status_[method] == 0);
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}
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auto instrumentation = art::Runtime::Current()->GetInstrumentation();
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if (UNLIKELY(instrumentation->IsForcedInterpretOnly())) {
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// We don't need to do anything since we are interpreting everything anyway.
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deoptimization_status_lock_.ExclusiveUnlock(self);
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return;
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} else if (is_last_breakpoint) {
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if (UNLIKELY(is_default)) {
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RemoveDeoptimizeAllMethodsLocked(self);
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} else {
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PerformLimitedUndeoptimization(self, method);
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}
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} else {
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// Another thread might be deoptimizing the very methods we just removed breakpoints from. Wait
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// for any deopts to finish before moving on.
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WaitForDeoptimizationToFinish(self);
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}
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}
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void DeoptManager::WaitForDeoptimizationToFinishLocked(art::Thread* self) {
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while (performing_deoptimization_) {
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deoptimization_condition_.Wait(self);
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}
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}
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void DeoptManager::WaitForDeoptimizationToFinish(art::Thread* self) {
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WaitForDeoptimizationToFinishLocked(self);
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deoptimization_status_lock_.ExclusiveUnlock(self);
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}
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// Users should make sure that only gc-critical-section safe code is used while a
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// ScopedDeoptimizationContext exists.
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class ScopedDeoptimizationContext : public art::ValueObject {
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public:
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ScopedDeoptimizationContext(art::Thread* self, DeoptManager* deopt)
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RELEASE(deopt->deoptimization_status_lock_)
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ACQUIRE(art::Locks::mutator_lock_)
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ACQUIRE(art::Roles::uninterruptible_)
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: self_(self),
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deopt_(deopt),
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critical_section_(self_, "JVMTI Deoptimizing methods"),
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uninterruptible_cause_(nullptr) {
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deopt_->WaitForDeoptimizationToFinishLocked(self_);
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DCHECK(!deopt->performing_deoptimization_)
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<< "Already performing deoptimization on another thread!";
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// Use performing_deoptimization_ to keep track of the lock.
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deopt_->performing_deoptimization_ = true;
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deopt_->deoptimization_status_lock_.Unlock(self_);
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uninterruptible_cause_ = critical_section_.Enter(art::gc::kGcCauseInstrumentation,
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art::gc::kCollectorTypeCriticalSection);
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art::Runtime::Current()->GetThreadList()->SuspendAll("JMVTI Deoptimizing methods",
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/*long_suspend=*/ false);
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}
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~ScopedDeoptimizationContext()
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RELEASE(art::Locks::mutator_lock_)
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RELEASE(art::Roles::uninterruptible_) {
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// Can be suspended again.
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critical_section_.Exit(uninterruptible_cause_);
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// Release the mutator lock.
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art::Runtime::Current()->GetThreadList()->ResumeAll();
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// Let other threads know it's fine to proceed.
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art::MutexLock lk(self_, deopt_->deoptimization_status_lock_);
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deopt_->performing_deoptimization_ = false;
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deopt_->deoptimization_condition_.Broadcast(self_);
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}
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private:
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art::Thread* self_;
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DeoptManager* deopt_;
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art::gc::GCCriticalSection critical_section_;
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const char* uninterruptible_cause_;
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};
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void DeoptManager::AddDeoptimizeAllMethodsLocked(art::Thread* self) {
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global_deopt_count_++;
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if (global_deopt_count_ == 1) {
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PerformGlobalDeoptimization(self);
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} else {
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WaitForDeoptimizationToFinish(self);
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}
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}
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void DeoptManager::RemoveDeoptimizeAllMethodsLocked(art::Thread* self) {
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DCHECK_GT(global_deopt_count_, 0u) << "Request to remove non-existent global deoptimization!";
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global_deopt_count_--;
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if (global_deopt_count_ == 0) {
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PerformGlobalUndeoptimization(self);
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} else {
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WaitForDeoptimizationToFinish(self);
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}
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}
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void DeoptManager::PerformLimitedDeoptimization(art::Thread* self, art::ArtMethod* method) {
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ScopedDeoptimizationContext sdc(self, this);
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art::Runtime::Current()->GetInstrumentation()->Deoptimize(method);
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}
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void DeoptManager::PerformLimitedUndeoptimization(art::Thread* self, art::ArtMethod* method) {
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ScopedDeoptimizationContext sdc(self, this);
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art::Runtime::Current()->GetInstrumentation()->Undeoptimize(method);
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}
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void DeoptManager::PerformGlobalDeoptimization(art::Thread* self) {
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ScopedDeoptimizationContext sdc(self, this);
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art::Runtime::Current()->GetInstrumentation()->DeoptimizeEverything(
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kDeoptManagerInstrumentationKey);
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}
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void DeoptManager::PerformGlobalUndeoptimization(art::Thread* self) {
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ScopedDeoptimizationContext sdc(self, this);
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art::Runtime::Current()->GetInstrumentation()->UndeoptimizeEverything(
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kDeoptManagerInstrumentationKey);
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}
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jvmtiError DeoptManager::AddDeoptimizeThreadMethods(art::ScopedObjectAccessUnchecked& soa, jthread jtarget) {
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art::Locks::thread_list_lock_->ExclusiveLock(soa.Self());
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art::Thread* target = nullptr;
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jvmtiError err = OK;
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if (!ThreadUtil::GetNativeThread(jtarget, soa, &target, &err)) {
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art::Locks::thread_list_lock_->ExclusiveUnlock(soa.Self());
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return err;
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}
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// We don't need additional locking here because we hold the Thread_list_lock_.
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if (target->IncrementForceInterpreterCount() == 1) {
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struct DeoptClosure : public art::Closure {
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public:
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explicit DeoptClosure(DeoptManager* man) : man_(man) {}
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void Run(art::Thread* self) override REQUIRES_SHARED(art::Locks::mutator_lock_) {
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man_->DeoptimizeThread(self);
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}
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private:
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DeoptManager* man_;
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};
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DeoptClosure c(this);
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target->RequestSynchronousCheckpoint(&c);
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} else {
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art::Locks::thread_list_lock_->ExclusiveUnlock(soa.Self());
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}
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return OK;
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}
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jvmtiError DeoptManager::RemoveDeoptimizeThreadMethods(art::ScopedObjectAccessUnchecked& soa, jthread jtarget) {
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art::MutexLock mu(soa.Self(), *art::Locks::thread_list_lock_);
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art::Thread* target = nullptr;
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jvmtiError err = OK;
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if (!ThreadUtil::GetNativeThread(jtarget, soa, &target, &err)) {
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return err;
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}
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// We don't need additional locking here because we hold the Thread_list_lock_.
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DCHECK_GT(target->ForceInterpreterCount(), 0u);
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target->DecrementForceInterpreterCount();
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return OK;
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}
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void DeoptManager::RemoveDeoptimizationRequester() {
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art::Thread* self = art::Thread::Current();
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art::ScopedThreadStateChange sts(self, art::kSuspended);
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deoptimization_status_lock_.ExclusiveLock(self);
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DCHECK_GT(deopter_count_, 0u) << "Removing deoptimization requester without any being present";
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deopter_count_--;
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if (deopter_count_ == 0) {
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ScopedDeoptimizationContext sdc(self, this);
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// TODO Give this a real key.
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art::Runtime::Current()->GetInstrumentation()->DisableDeoptimization("");
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return;
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} else {
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deoptimization_status_lock_.ExclusiveUnlock(self);
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}
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}
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void DeoptManager::AddDeoptimizationRequester() {
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art::Thread* self = art::Thread::Current();
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art::ScopedThreadStateChange stsc(self, art::kSuspended);
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deoptimization_status_lock_.ExclusiveLock(self);
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deopter_count_++;
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if (deopter_count_ == 1) {
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ScopedDeoptimizationContext sdc(self, this);
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art::instrumentation::Instrumentation* instrumentation =
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art::Runtime::Current()->GetInstrumentation();
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// Enable deoptimization
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instrumentation->EnableDeoptimization();
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// Tell instrumentation we will be deopting single threads.
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instrumentation->EnableSingleThreadDeopt();
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} else {
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deoptimization_status_lock_.ExclusiveUnlock(self);
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}
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}
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void DeoptManager::DeoptimizeThread(art::Thread* target) {
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// We might or might not be running on the target thread (self) so get Thread::Current
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// directly.
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art::gc::ScopedGCCriticalSection sgccs(art::Thread::Current(),
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art::gc::GcCause::kGcCauseDebugger,
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art::gc::CollectorType::kCollectorTypeDebugger);
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art::Runtime::Current()->GetInstrumentation()->InstrumentThreadStack(target);
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}
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extern DeoptManager* gDeoptManager;
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DeoptManager* DeoptManager::Get() {
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return gDeoptManager;
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}
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} // namespace openjdkjvmti
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