blob: d2f3c54738484c732156b1fb681370cf6047299e [file] [log] [blame]
// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/wasm/wasm-engine.h"
#include "src/base/platform/time.h"
#include "src/diagnostics/code-tracer.h"
#include "src/diagnostics/compilation-statistics.h"
#include "src/execution/frames.h"
#include "src/logging/counters.h"
#include "src/objects/heap-number.h"
#include "src/objects/js-promise.h"
#include "src/objects/objects-inl.h"
#include "src/utils/ostreams.h"
#include "src/wasm/function-compiler.h"
#include "src/wasm/module-compiler.h"
#include "src/wasm/module-decoder.h"
#include "src/wasm/module-instantiate.h"
#include "src/wasm/streaming-decoder.h"
#include "src/wasm/wasm-objects-inl.h"
namespace v8 {
namespace internal {
namespace wasm {
#define TRACE_CODE_GC(...) \
do { \
if (FLAG_trace_wasm_code_gc) PrintF("[wasm-gc] " __VA_ARGS__); \
} while (false)
namespace {
// A task to log a set of {WasmCode} objects in an isolate. It does not own any
// data itself, since it is owned by the platform, so lifetime is not really
// bound to the wasm engine.
class LogCodesTask : public Task {
public:
LogCodesTask(base::Mutex* mutex, LogCodesTask** task_slot, Isolate* isolate,
WasmEngine* engine)
: mutex_(mutex),
task_slot_(task_slot),
isolate_(isolate),
engine_(engine) {
DCHECK_NOT_NULL(task_slot);
DCHECK_NOT_NULL(isolate);
}
~LogCodesTask() {
// If the platform deletes this task before executing it, we also deregister
// it to avoid use-after-free from still-running background threads.
if (!cancelled()) DeregisterTask();
}
void Run() override {
if (cancelled()) return;
DeregisterTask();
engine_->LogOutstandingCodesForIsolate(isolate_);
}
void Cancel() {
// Cancel will only be called on Isolate shutdown, which happens on the
// Isolate's foreground thread. Thus no synchronization needed.
isolate_ = nullptr;
}
bool cancelled() const { return isolate_ == nullptr; }
void DeregisterTask() {
// The task will only be deregistered from the foreground thread (executing
// this task or calling its destructor), thus we do not need synchronization
// on this field access.
if (task_slot_ == nullptr) return; // already deregistered.
// Remove this task from the {IsolateInfo} in the engine. The next
// logging request will allocate and schedule a new task.
base::MutexGuard guard(mutex_);
DCHECK_EQ(this, *task_slot_);
*task_slot_ = nullptr;
task_slot_ = nullptr;
}
private:
// The mutex of the WasmEngine.
base::Mutex* const mutex_;
// The slot in the WasmEngine where this LogCodesTask is stored. This is
// cleared by this task before execution or on task destruction.
LogCodesTask** task_slot_;
Isolate* isolate_;
WasmEngine* const engine_;
};
class WasmGCForegroundTask : public Task {
public:
explicit WasmGCForegroundTask(Isolate* isolate) : isolate_(isolate) {
DCHECK_NOT_NULL(isolate);
}
void Run() final {
if (isolate_ == nullptr) return; // cancelled.
WasmEngine* engine = isolate_->wasm_engine();
// If the foreground task is executing, there is no wasm code active. Just
// report an empty set of live wasm code.
#ifdef ENABLE_SLOW_DCHECKS
for (StackFrameIterator it(isolate_); !it.done(); it.Advance()) {
DCHECK_NE(StackFrame::WASM_COMPILED, it.frame()->type());
}
#endif
engine->ReportLiveCodeForGC(isolate_, Vector<WasmCode*>{});
}
void Cancel() { isolate_ = nullptr; }
private:
Isolate* isolate_;
};
} // namespace
struct WasmEngine::CurrentGCInfo {
explicit CurrentGCInfo(int8_t gc_sequence_index)
: gc_sequence_index(gc_sequence_index) {
DCHECK_NE(0, gc_sequence_index);
}
// Set of isolates that did not scan their stack yet for used WasmCode, and
// their scheduled foreground task.
std::unordered_map<Isolate*, WasmGCForegroundTask*> outstanding_isolates;
// Set of dead code. Filled with all potentially dead code on initialization.
// Code that is still in-use is removed by the individual isolates.
std::unordered_set<WasmCode*> dead_code;
// The number of GCs triggered in the native module that triggered this GC.
// This is stored in the histogram for each participating isolate during
// execution of that isolate's foreground task.
const int8_t gc_sequence_index;
// If during this GC, another GC was requested, we skipped that other GC (we
// only run one GC at a time). Remember though to trigger another one once
// this one finishes. {next_gc_sequence_index} is 0 if no next GC is needed,
// and >0 otherwise. It stores the {num_code_gcs_triggered} of the native
// module which triggered the next GC.
int8_t next_gc_sequence_index = 0;
// The start time of this GC; used for tracing and sampled via {Counters}.
// Can be null ({TimeTicks::IsNull()}) if timer is not high resolution.
base::TimeTicks start_time;
};
struct WasmEngine::IsolateInfo {
explicit IsolateInfo(Isolate* isolate)
: log_codes(WasmCode::ShouldBeLogged(isolate)),
async_counters(isolate->async_counters()) {
v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate);
v8::Platform* platform = V8::GetCurrentPlatform();
foreground_task_runner = platform->GetForegroundTaskRunner(v8_isolate);
}
#ifdef DEBUG
~IsolateInfo() {
// Before destructing, the {WasmEngine} must have cleared outstanding code
// to log.
DCHECK_EQ(0, code_to_log.size());
}
#endif
// All native modules that are being used by this Isolate (currently only
// grows, never shrinks).
std::set<NativeModule*> native_modules;
// Caches whether code needs to be logged on this isolate.
bool log_codes;
// The currently scheduled LogCodesTask.
LogCodesTask* log_codes_task = nullptr;
// The vector of code objects that still need to be logged in this isolate.
std::vector<WasmCode*> code_to_log;
// The foreground task runner of the isolate (can be called from background).
std::shared_ptr<v8::TaskRunner> foreground_task_runner;
const std::shared_ptr<Counters> async_counters;
};
struct WasmEngine::NativeModuleInfo {
// Set of isolates using this NativeModule.
std::unordered_set<Isolate*> isolates;
// Set of potentially dead code. This set holds one ref for each code object,
// until code is detected to be really dead. At that point, the ref count is
// decremented and code is move to the {dead_code} set. If the code is finally
// deleted, it is also removed from {dead_code}.
std::unordered_set<WasmCode*> potentially_dead_code;
// Code that is not being executed in any isolate any more, but the ref count
// did not drop to zero yet.
std::unordered_set<WasmCode*> dead_code;
// Number of code GCs triggered because code in this native module became
// potentially dead.
int8_t num_code_gcs_triggered = 0;
};
WasmEngine::WasmEngine()
: code_manager_(&memory_tracker_, FLAG_wasm_max_code_space * MB) {}
WasmEngine::~WasmEngine() {
// Synchronize on all background compile tasks.
background_compile_task_manager_.CancelAndWait();
// All AsyncCompileJobs have been canceled.
DCHECK(async_compile_jobs_.empty());
// All Isolates have been deregistered.
DCHECK(isolates_.empty());
// All NativeModules did die.
DCHECK(native_modules_.empty());
}
bool WasmEngine::SyncValidate(Isolate* isolate, const WasmFeatures& enabled,
const ModuleWireBytes& bytes) {
// TODO(titzer): remove dependency on the isolate.
if (bytes.start() == nullptr || bytes.length() == 0) return false;
ModuleResult result =
DecodeWasmModule(enabled, bytes.start(), bytes.end(), true, kWasmOrigin,
isolate->counters(), allocator());
return result.ok();
}
MaybeHandle<AsmWasmData> WasmEngine::SyncCompileTranslatedAsmJs(
Isolate* isolate, ErrorThrower* thrower, const ModuleWireBytes& bytes,
Vector<const byte> asm_js_offset_table_bytes,
Handle<HeapNumber> uses_bitset) {
ModuleResult result =
DecodeWasmModule(kAsmjsWasmFeatures, bytes.start(), bytes.end(), false,
kAsmJsOrigin, isolate->counters(), allocator());
if (result.failed()) {
// This happens once in a while when we have missed some limit check
// in the asm parser. Output an error message to help diagnose, but crash.
std::cout << result.error().message();
UNREACHABLE();
}
// Transfer ownership of the WasmModule to the {Managed<WasmModule>} generated
// in {CompileToNativeModule}.
Handle<FixedArray> export_wrappers;
std::shared_ptr<NativeModule> native_module =
CompileToNativeModule(isolate, kAsmjsWasmFeatures, thrower,
std::move(result).value(), bytes, &export_wrappers);
if (!native_module) return {};
// Create heap objects for asm.js offset table to be stored in the module
// object.
Handle<ByteArray> asm_js_offset_table =
isolate->factory()->NewByteArray(asm_js_offset_table_bytes.length());
asm_js_offset_table->copy_in(0, asm_js_offset_table_bytes.begin(),
asm_js_offset_table_bytes.length());
return AsmWasmData::New(isolate, std::move(native_module), export_wrappers,
asm_js_offset_table, uses_bitset);
}
Handle<WasmModuleObject> WasmEngine::FinalizeTranslatedAsmJs(
Isolate* isolate, Handle<AsmWasmData> asm_wasm_data,
Handle<Script> script) {
std::shared_ptr<NativeModule> native_module =
asm_wasm_data->managed_native_module().get();
Handle<FixedArray> export_wrappers =
handle(asm_wasm_data->export_wrappers(), isolate);
size_t code_size_estimate =
wasm::WasmCodeManager::EstimateNativeModuleCodeSize(
native_module->module());
Handle<WasmModuleObject> module_object =
WasmModuleObject::New(isolate, std::move(native_module), script,
export_wrappers, code_size_estimate);
module_object->set_asm_js_offset_table(asm_wasm_data->asm_js_offset_table());
return module_object;
}
MaybeHandle<WasmModuleObject> WasmEngine::SyncCompile(
Isolate* isolate, const WasmFeatures& enabled, ErrorThrower* thrower,
const ModuleWireBytes& bytes) {
ModuleResult result =
DecodeWasmModule(enabled, bytes.start(), bytes.end(), false, kWasmOrigin,
isolate->counters(), allocator());
if (result.failed()) {
thrower->CompileFailed(result.error());
return {};
}
// Transfer ownership of the WasmModule to the {Managed<WasmModule>} generated
// in {CompileToModuleObject}.
Handle<FixedArray> export_wrappers;
std::shared_ptr<NativeModule> native_module =
CompileToNativeModule(isolate, enabled, thrower,
std::move(result).value(), bytes, &export_wrappers);
if (!native_module) return {};
Handle<Script> script =
CreateWasmScript(isolate, bytes, native_module->module()->source_map_url);
size_t code_size_estimate =
wasm::WasmCodeManager::EstimateNativeModuleCodeSize(
native_module->module());
// Create the module object.
// TODO(clemensh): For the same module (same bytes / same hash), we should
// only have one WasmModuleObject. Otherwise, we might only set
// breakpoints on a (potentially empty) subset of the instances.
// Create the compiled module object and populate with compiled functions
// and information needed at instantiation time. This object needs to be
// serializable. Instantiation may occur off a deserialized version of this
// object.
Handle<WasmModuleObject> module_object =
WasmModuleObject::New(isolate, std::move(native_module), script,
export_wrappers, code_size_estimate);
// Finish the Wasm script now and make it public to the debugger.
isolate->debug()->OnAfterCompile(script);
return module_object;
}
MaybeHandle<WasmInstanceObject> WasmEngine::SyncInstantiate(
Isolate* isolate, ErrorThrower* thrower,
Handle<WasmModuleObject> module_object, MaybeHandle<JSReceiver> imports,
MaybeHandle<JSArrayBuffer> memory) {
return InstantiateToInstanceObject(isolate, thrower, module_object, imports,
memory);
}
void WasmEngine::AsyncInstantiate(
Isolate* isolate, std::unique_ptr<InstantiationResultResolver> resolver,
Handle<WasmModuleObject> module_object, MaybeHandle<JSReceiver> imports) {
ErrorThrower thrower(isolate, "WebAssembly.instantiate()");
// Instantiate a TryCatch so that caught exceptions won't progagate out.
// They will still be set as pending exceptions on the isolate.
// TODO(clemensh): Avoid TryCatch, use Execution::TryCall internally to invoke
// start function and report thrown exception explicitly via out argument.
v8::TryCatch catcher(reinterpret_cast<v8::Isolate*>(isolate));
catcher.SetVerbose(false);
catcher.SetCaptureMessage(false);
MaybeHandle<WasmInstanceObject> instance_object = SyncInstantiate(
isolate, &thrower, module_object, imports, Handle<JSArrayBuffer>::null());
if (!instance_object.is_null()) {
resolver->OnInstantiationSucceeded(instance_object.ToHandleChecked());
return;
}
if (isolate->has_pending_exception()) {
// The JS code executed during instantiation has thrown an exception.
// We have to move the exception to the promise chain.
Handle<Object> exception(isolate->pending_exception(), isolate);
isolate->clear_pending_exception();
*isolate->external_caught_exception_address() = false;
resolver->OnInstantiationFailed(exception);
thrower.Reset();
} else {
DCHECK(thrower.error());
resolver->OnInstantiationFailed(thrower.Reify());
}
}
void WasmEngine::AsyncCompile(
Isolate* isolate, const WasmFeatures& enabled,
std::shared_ptr<CompilationResultResolver> resolver,
const ModuleWireBytes& bytes, bool is_shared,
const char* api_method_name_for_errors) {
if (!FLAG_wasm_async_compilation) {
// Asynchronous compilation disabled; fall back on synchronous compilation.
ErrorThrower thrower(isolate, api_method_name_for_errors);
MaybeHandle<WasmModuleObject> module_object;
if (is_shared) {
// Make a copy of the wire bytes to avoid concurrent modification.
std::unique_ptr<uint8_t[]> copy(new uint8_t[bytes.length()]);
memcpy(copy.get(), bytes.start(), bytes.length());
ModuleWireBytes bytes_copy(copy.get(), copy.get() + bytes.length());
module_object = SyncCompile(isolate, enabled, &thrower, bytes_copy);
} else {
// The wire bytes are not shared, OK to use them directly.
module_object = SyncCompile(isolate, enabled, &thrower, bytes);
}
if (thrower.error()) {
resolver->OnCompilationFailed(thrower.Reify());
return;
}
Handle<WasmModuleObject> module = module_object.ToHandleChecked();
resolver->OnCompilationSucceeded(module);
return;
}
if (FLAG_wasm_test_streaming) {
std::shared_ptr<StreamingDecoder> streaming_decoder =
StartStreamingCompilation(
isolate, enabled, handle(isolate->context(), isolate),
api_method_name_for_errors, std::move(resolver));
streaming_decoder->OnBytesReceived(bytes.module_bytes());
streaming_decoder->Finish();
return;
}
// Make a copy of the wire bytes in case the user program changes them
// during asynchronous compilation.
std::unique_ptr<byte[]> copy(new byte[bytes.length()]);
memcpy(copy.get(), bytes.start(), bytes.length());
AsyncCompileJob* job =
CreateAsyncCompileJob(isolate, enabled, std::move(copy), bytes.length(),
handle(isolate->context(), isolate),
api_method_name_for_errors, std::move(resolver));
job->Start();
}
std::shared_ptr<StreamingDecoder> WasmEngine::StartStreamingCompilation(
Isolate* isolate, const WasmFeatures& enabled, Handle<Context> context,
const char* api_method_name,
std::shared_ptr<CompilationResultResolver> resolver) {
AsyncCompileJob* job =
CreateAsyncCompileJob(isolate, enabled, std::unique_ptr<byte[]>(nullptr),
0, context, api_method_name, std::move(resolver));
return job->CreateStreamingDecoder();
}
void WasmEngine::CompileFunction(Isolate* isolate, NativeModule* native_module,
uint32_t function_index, ExecutionTier tier) {
// Note we assume that "one-off" compilations can discard detected features.
WasmFeatures detected = kNoWasmFeatures;
WasmCompilationUnit::CompileWasmFunction(
isolate, native_module, &detected,
&native_module->module()->functions[function_index], tier);
}
std::shared_ptr<NativeModule> WasmEngine::ExportNativeModule(
Handle<WasmModuleObject> module_object) {
return module_object->shared_native_module();
}
Handle<WasmModuleObject> WasmEngine::ImportNativeModule(
Isolate* isolate, std::shared_ptr<NativeModule> shared_native_module) {
NativeModule* native_module = shared_native_module.get();
ModuleWireBytes wire_bytes(native_module->wire_bytes());
const WasmModule* module = native_module->module();
Handle<Script> script =
CreateWasmScript(isolate, wire_bytes, module->source_map_url);
size_t code_size = native_module->committed_code_space();
Handle<WasmModuleObject> module_object = WasmModuleObject::New(
isolate, std::move(shared_native_module), script, code_size);
CompileJsToWasmWrappers(isolate, native_module->module(),
handle(module_object->export_wrappers(), isolate));
{
base::MutexGuard lock(&mutex_);
DCHECK_EQ(1, isolates_.count(isolate));
isolates_[isolate]->native_modules.insert(native_module);
DCHECK_EQ(1, native_modules_.count(native_module));
native_modules_[native_module]->isolates.insert(isolate);
}
return module_object;
}
CompilationStatistics* WasmEngine::GetOrCreateTurboStatistics() {
base::MutexGuard guard(&mutex_);
if (compilation_stats_ == nullptr) {
compilation_stats_.reset(new CompilationStatistics());
}
return compilation_stats_.get();
}
void WasmEngine::DumpAndResetTurboStatistics() {
base::MutexGuard guard(&mutex_);
if (compilation_stats_ != nullptr) {
StdoutStream os;
os << AsPrintableStatistics{*compilation_stats_.get(), false} << std::endl;
}
compilation_stats_.reset();
}
CodeTracer* WasmEngine::GetCodeTracer() {
base::MutexGuard guard(&mutex_);
if (code_tracer_ == nullptr) code_tracer_.reset(new CodeTracer(-1));
return code_tracer_.get();
}
AsyncCompileJob* WasmEngine::CreateAsyncCompileJob(
Isolate* isolate, const WasmFeatures& enabled,
std::unique_ptr<byte[]> bytes_copy, size_t length, Handle<Context> context,
const char* api_method_name,
std::shared_ptr<CompilationResultResolver> resolver) {
AsyncCompileJob* job =
new AsyncCompileJob(isolate, enabled, std::move(bytes_copy), length,
context, api_method_name, std::move(resolver));
// Pass ownership to the unique_ptr in {async_compile_jobs_}.
base::MutexGuard guard(&mutex_);
async_compile_jobs_[job] = std::unique_ptr<AsyncCompileJob>(job);
return job;
}
std::unique_ptr<AsyncCompileJob> WasmEngine::RemoveCompileJob(
AsyncCompileJob* job) {
base::MutexGuard guard(&mutex_);
auto item = async_compile_jobs_.find(job);
DCHECK(item != async_compile_jobs_.end());
std::unique_ptr<AsyncCompileJob> result = std::move(item->second);
async_compile_jobs_.erase(item);
return result;
}
bool WasmEngine::HasRunningCompileJob(Isolate* isolate) {
base::MutexGuard guard(&mutex_);
DCHECK_EQ(1, isolates_.count(isolate));
for (auto& entry : async_compile_jobs_) {
if (entry.first->isolate() == isolate) return true;
}
return false;
}
void WasmEngine::DeleteCompileJobsOnIsolate(Isolate* isolate) {
// Under the mutex get all jobs to delete. Then delete them without holding
// the mutex, such that deletion can reenter the WasmEngine.
std::vector<std::unique_ptr<AsyncCompileJob>> jobs_to_delete;
{
base::MutexGuard guard(&mutex_);
DCHECK_EQ(1, isolates_.count(isolate));
for (auto it = async_compile_jobs_.begin();
it != async_compile_jobs_.end();) {
if (it->first->isolate() != isolate) {
++it;
continue;
}
jobs_to_delete.push_back(std::move(it->second));
it = async_compile_jobs_.erase(it);
}
}
}
namespace {
int GetGCTimeMicros(base::TimeTicks start) {
DCHECK(!start.IsNull());
int64_t duration_us = (base::TimeTicks::Now() - start).InMicroseconds();
return static_cast<int>(
std::min(std::max(int64_t{0}, duration_us), int64_t{kMaxInt}));
}
} // namespace
void WasmEngine::AddIsolate(Isolate* isolate) {
base::MutexGuard guard(&mutex_);
DCHECK_EQ(0, isolates_.count(isolate));
isolates_.emplace(isolate, base::make_unique<IsolateInfo>(isolate));
// Install sampling GC callback.
// TODO(v8:7424): For now we sample module sizes in a GC callback. This will
// bias samples towards apps with high memory pressure. We should switch to
// using sampling based on regular intervals independent of the GC.
auto callback = [](v8::Isolate* v8_isolate, v8::GCType type,
v8::GCCallbackFlags flags, void* data) {
Isolate* isolate = reinterpret_cast<Isolate*>(v8_isolate);
Counters* counters = isolate->counters();
WasmEngine* engine = isolate->wasm_engine();
base::MutexGuard lock(&engine->mutex_);
DCHECK_EQ(1, engine->isolates_.count(isolate));
for (auto* native_module : engine->isolates_[isolate]->native_modules) {
native_module->SampleCodeSize(counters, NativeModule::kSampling);
}
// If there is an ongoing code GC, sample its time here. This will record
// samples for very long-running or never ending GCs.
if (engine->current_gc_info_ &&
!engine->current_gc_info_->start_time.IsNull()) {
isolate->counters()->wasm_code_gc_time()->AddSample(
GetGCTimeMicros(engine->current_gc_info_->start_time));
}
};
isolate->heap()->AddGCEpilogueCallback(callback, v8::kGCTypeMarkSweepCompact,
nullptr);
}
void WasmEngine::RemoveIsolate(Isolate* isolate) {
base::MutexGuard guard(&mutex_);
auto it = isolates_.find(isolate);
DCHECK_NE(isolates_.end(), it);
std::unique_ptr<IsolateInfo> info = std::move(it->second);
isolates_.erase(it);
for (NativeModule* native_module : info->native_modules) {
DCHECK_EQ(1, native_modules_.count(native_module));
DCHECK_EQ(1, native_modules_[native_module]->isolates.count(isolate));
auto* info = native_modules_[native_module].get();
info->isolates.erase(isolate);
if (current_gc_info_) {
for (WasmCode* code : info->potentially_dead_code) {
current_gc_info_->dead_code.erase(code);
}
}
}
if (current_gc_info_) {
if (RemoveIsolateFromCurrentGC(isolate)) PotentiallyFinishCurrentGC();
}
if (auto* task = info->log_codes_task) task->Cancel();
if (!info->code_to_log.empty()) {
WasmCode::DecrementRefCount(VectorOf(info->code_to_log));
info->code_to_log.clear();
}
}
void WasmEngine::LogCode(WasmCode* code) {
base::MutexGuard guard(&mutex_);
NativeModule* native_module = code->native_module();
DCHECK_EQ(1, native_modules_.count(native_module));
for (Isolate* isolate : native_modules_[native_module]->isolates) {
DCHECK_EQ(1, isolates_.count(isolate));
IsolateInfo* info = isolates_[isolate].get();
if (info->log_codes == false) continue;
if (info->log_codes_task == nullptr) {
auto new_task = base::make_unique<LogCodesTask>(
&mutex_, &info->log_codes_task, isolate, this);
info->log_codes_task = new_task.get();
info->foreground_task_runner->PostTask(std::move(new_task));
}
if (info->code_to_log.empty()) {
isolate->stack_guard()->RequestLogWasmCode();
}
info->code_to_log.push_back(code);
code->IncRef();
}
}
void WasmEngine::EnableCodeLogging(Isolate* isolate) {
base::MutexGuard guard(&mutex_);
auto it = isolates_.find(isolate);
DCHECK_NE(isolates_.end(), it);
it->second->log_codes = true;
}
void WasmEngine::LogOutstandingCodesForIsolate(Isolate* isolate) {
// If by now we should not log code any more, do not log it.
if (!WasmCode::ShouldBeLogged(isolate)) return;
// Under the mutex, get the vector of wasm code to log. Then log and decrement
// the ref count without holding the mutex.
std::vector<WasmCode*> code_to_log;
{
base::MutexGuard guard(&mutex_);
DCHECK_EQ(1, isolates_.count(isolate));
code_to_log.swap(isolates_[isolate]->code_to_log);
}
if (code_to_log.empty()) return;
for (WasmCode* code : code_to_log) {
code->LogCode(isolate);
}
WasmCode::DecrementRefCount(VectorOf(code_to_log));
}
std::shared_ptr<NativeModule> WasmEngine::NewNativeModule(
Isolate* isolate, const WasmFeatures& enabled, size_t code_size_estimate,
bool can_request_more, std::shared_ptr<const WasmModule> module) {
std::shared_ptr<NativeModule> native_module =
code_manager_.NewNativeModule(this, isolate, enabled, code_size_estimate,
can_request_more, std::move(module));
base::MutexGuard lock(&mutex_);
auto pair = native_modules_.insert(std::make_pair(
native_module.get(), base::make_unique<NativeModuleInfo>()));
DCHECK(pair.second); // inserted new entry.
pair.first->second.get()->isolates.insert(isolate);
isolates_[isolate]->native_modules.insert(native_module.get());
return native_module;
}
void WasmEngine::FreeNativeModule(NativeModule* native_module) {
base::MutexGuard guard(&mutex_);
auto it = native_modules_.find(native_module);
DCHECK_NE(native_modules_.end(), it);
for (Isolate* isolate : it->second->isolates) {
DCHECK_EQ(1, isolates_.count(isolate));
IsolateInfo* info = isolates_[isolate].get();
DCHECK_EQ(1, info->native_modules.count(native_module));
info->native_modules.erase(native_module);
// If there are {WasmCode} objects of the deleted {NativeModule}
// outstanding to be logged in this isolate, remove them. Decrementing the
// ref count is not needed, since the {NativeModule} dies anyway.
size_t remaining = info->code_to_log.size();
if (remaining > 0) {
for (size_t i = 0; i < remaining; ++i) {
while (i < remaining &&
info->code_to_log[i]->native_module() == native_module) {
// Move the last remaining item to this slot (this can be the same
// as {i}, which is OK).
info->code_to_log[i] = info->code_to_log[--remaining];
}
}
info->code_to_log.resize(remaining);
}
}
// If there is a GC running which has references to code contained in the
// deleted {NativeModule}, remove those references.
if (current_gc_info_) {
for (auto it = current_gc_info_->dead_code.begin(),
end = current_gc_info_->dead_code.end();
it != end;) {
if ((*it)->native_module() == native_module) {
it = current_gc_info_->dead_code.erase(it);
} else {
++it;
}
}
TRACE_CODE_GC("Native module %p died, reducing dead code objects to %zu.\n",
native_module, current_gc_info_->dead_code.size());
}
native_modules_.erase(it);
}
namespace {
class SampleTopTierCodeSizeTask : public CancelableTask {
public:
SampleTopTierCodeSizeTask(Isolate* isolate,
std::weak_ptr<NativeModule> native_module)
: CancelableTask(isolate),
isolate_(isolate),
native_module_(std::move(native_module)) {}
void RunInternal() override {
if (std::shared_ptr<NativeModule> native_module = native_module_.lock()) {
native_module->SampleCodeSize(isolate_->counters(),
NativeModule::kAfterTopTier);
}
}
private:
Isolate* const isolate_;
const std::weak_ptr<NativeModule> native_module_;
};
} // namespace
void WasmEngine::SampleTopTierCodeSizeInAllIsolates(
const std::shared_ptr<NativeModule>& native_module) {
base::MutexGuard lock(&mutex_);
DCHECK_EQ(1, native_modules_.count(native_module.get()));
for (Isolate* isolate : native_modules_[native_module.get()]->isolates) {
DCHECK_EQ(1, isolates_.count(isolate));
IsolateInfo* info = isolates_[isolate].get();
info->foreground_task_runner->PostTask(
base::make_unique<SampleTopTierCodeSizeTask>(isolate, native_module));
}
}
void WasmEngine::ReportLiveCodeForGC(Isolate* isolate,
Vector<WasmCode*> live_code) {
TRACE_CODE_GC("Isolate %d reporting %zu live code objects.\n", isolate->id(),
live_code.size());
base::MutexGuard guard(&mutex_);
// This report might come in late (note that we trigger both a stack guard and
// a foreground task). In that case, ignore it.
if (current_gc_info_ == nullptr) return;
if (!RemoveIsolateFromCurrentGC(isolate)) return;
isolate->counters()->wasm_module_num_triggered_code_gcs()->AddSample(
current_gc_info_->gc_sequence_index);
for (WasmCode* code : live_code) current_gc_info_->dead_code.erase(code);
PotentiallyFinishCurrentGC();
}
void WasmEngine::ReportLiveCodeFromStackForGC(Isolate* isolate) {
wasm::WasmCodeRefScope code_ref_scope;
std::unordered_set<wasm::WasmCode*> live_wasm_code;
for (StackFrameIterator it(isolate); !it.done(); it.Advance()) {
StackFrame* const frame = it.frame();
if (frame->type() != StackFrame::WASM_COMPILED) continue;
live_wasm_code.insert(WasmCompiledFrame::cast(frame)->wasm_code());
}
ReportLiveCodeForGC(isolate,
OwnedVector<WasmCode*>::Of(live_wasm_code).as_vector());
}
bool WasmEngine::AddPotentiallyDeadCode(WasmCode* code) {
base::MutexGuard guard(&mutex_);
auto it = native_modules_.find(code->native_module());
DCHECK_NE(native_modules_.end(), it);
NativeModuleInfo* info = it->second.get();
if (info->dead_code.count(code)) return false; // Code is already dead.
auto added = info->potentially_dead_code.insert(code);
if (!added.second) return false; // An entry already existed.
new_potentially_dead_code_size_ += code->instructions().size();
if (FLAG_wasm_code_gc) {
// Trigger a GC if 64kB plus 10% of committed code are potentially dead.
size_t dead_code_limit =
FLAG_stress_wasm_code_gc
? 0
: 64 * KB + code_manager_.committed_code_space() / 10;
if (new_potentially_dead_code_size_ > dead_code_limit) {
bool inc_gc_count =
info->num_code_gcs_triggered < std::numeric_limits<int8_t>::max();
if (current_gc_info_ == nullptr) {
if (inc_gc_count) ++info->num_code_gcs_triggered;
TRACE_CODE_GC(
"Triggering GC (potentially dead: %zu bytes; limit: %zu bytes).\n",
new_potentially_dead_code_size_, dead_code_limit);
TriggerGC(info->num_code_gcs_triggered);
} else if (current_gc_info_->next_gc_sequence_index == 0) {
if (inc_gc_count) ++info->num_code_gcs_triggered;
TRACE_CODE_GC(
"Scheduling another GC after the current one (potentially dead: "
"%zu bytes; limit: %zu bytes).\n",
new_potentially_dead_code_size_, dead_code_limit);
current_gc_info_->next_gc_sequence_index = info->num_code_gcs_triggered;
DCHECK_NE(0, current_gc_info_->next_gc_sequence_index);
}
}
}
return true;
}
void WasmEngine::FreeDeadCode(const DeadCodeMap& dead_code) {
base::MutexGuard guard(&mutex_);
FreeDeadCodeLocked(dead_code);
}
void WasmEngine::FreeDeadCodeLocked(const DeadCodeMap& dead_code) {
DCHECK(!mutex_.TryLock());
for (auto& dead_code_entry : dead_code) {
NativeModule* native_module = dead_code_entry.first;
const std::vector<WasmCode*>& code_vec = dead_code_entry.second;
DCHECK_EQ(1, native_modules_.count(native_module));
auto* info = native_modules_[native_module].get();
TRACE_CODE_GC("Freeing %zu code object%s of module %p.\n", code_vec.size(),
code_vec.size() == 1 ? "" : "s", native_module);
for (WasmCode* code : code_vec) {
DCHECK_EQ(1, info->dead_code.count(code));
info->dead_code.erase(code);
}
native_module->FreeCode(VectorOf(code_vec));
}
}
void WasmEngine::TriggerGC(int8_t gc_sequence_index) {
DCHECK_NULL(current_gc_info_);
DCHECK(FLAG_wasm_code_gc);
new_potentially_dead_code_size_ = 0;
current_gc_info_.reset(new CurrentGCInfo(gc_sequence_index));
if (base::TimeTicks::IsHighResolution()) {
current_gc_info_->start_time = base::TimeTicks::Now();
}
// Add all potentially dead code to this GC, and trigger a GC task in each
// isolate.
for (auto& entry : native_modules_) {
NativeModuleInfo* info = entry.second.get();
if (info->potentially_dead_code.empty()) continue;
for (auto* isolate : native_modules_[entry.first]->isolates) {
auto& gc_task = current_gc_info_->outstanding_isolates[isolate];
if (!gc_task) {
auto new_task = base::make_unique<WasmGCForegroundTask>(isolate);
gc_task = new_task.get();
DCHECK_EQ(1, isolates_.count(isolate));
isolates_[isolate]->foreground_task_runner->PostTask(
std::move(new_task));
}
isolate->stack_guard()->RequestWasmCodeGC();
}
for (WasmCode* code : info->potentially_dead_code) {
current_gc_info_->dead_code.insert(code);
}
}
TRACE_CODE_GC(
"Starting GC. Total number of potentially dead code objects: %zu\n",
current_gc_info_->dead_code.size());
}
bool WasmEngine::RemoveIsolateFromCurrentGC(Isolate* isolate) {
DCHECK(!mutex_.TryLock());
DCHECK_NOT_NULL(current_gc_info_);
auto it = current_gc_info_->outstanding_isolates.find(isolate);
if (it == current_gc_info_->outstanding_isolates.end()) return false;
if (auto* fg_task = it->second) fg_task->Cancel();
current_gc_info_->outstanding_isolates.erase(it);
return true;
}
void WasmEngine::PotentiallyFinishCurrentGC() {
DCHECK(!mutex_.TryLock());
TRACE_CODE_GC(
"Remaining dead code objects: %zu; outstanding isolates: %zu.\n",
current_gc_info_->dead_code.size(),
current_gc_info_->outstanding_isolates.size());
// If there are more outstanding isolates, return immediately.
if (!current_gc_info_->outstanding_isolates.empty()) return;
// All remaining code in {current_gc_info->dead_code} is really dead.
// Move it from the set of potentially dead code to the set of dead code,
// and decrement its ref count.
size_t num_freed = 0;
DeadCodeMap dead_code;
for (WasmCode* code : current_gc_info_->dead_code) {
DCHECK_EQ(1, native_modules_.count(code->native_module()));
auto* native_module_info = native_modules_[code->native_module()].get();
DCHECK_EQ(1, native_module_info->potentially_dead_code.count(code));
native_module_info->potentially_dead_code.erase(code);
DCHECK_EQ(0, native_module_info->dead_code.count(code));
native_module_info->dead_code.insert(code);
if (code->DecRefOnDeadCode()) {
dead_code[code->native_module()].push_back(code);
++num_freed;
}
}
FreeDeadCodeLocked(dead_code);
int duration_us = 0;
if (!current_gc_info_->start_time.IsNull()) {
duration_us = GetGCTimeMicros(current_gc_info_->start_time);
for (auto& entry : isolates_) {
entry.second->async_counters->wasm_code_gc_time()->AddSample(duration_us);
}
}
TRACE_CODE_GC("Took %d us; found %zu dead code objects, freed %zu.\n",
duration_us, current_gc_info_->dead_code.size(), num_freed);
USE(num_freed);
int8_t next_gc_sequence_index = current_gc_info_->next_gc_sequence_index;
current_gc_info_.reset();
if (next_gc_sequence_index != 0) TriggerGC(next_gc_sequence_index);
}
namespace {
DEFINE_LAZY_LEAKY_OBJECT_GETTER(std::shared_ptr<WasmEngine>,
GetSharedWasmEngine)
} // namespace
// static
void WasmEngine::InitializeOncePerProcess() {
if (!FLAG_wasm_shared_engine) return;
*GetSharedWasmEngine() = std::make_shared<WasmEngine>();
}
// static
void WasmEngine::GlobalTearDown() {
if (!FLAG_wasm_shared_engine) return;
GetSharedWasmEngine()->reset();
}
// static
std::shared_ptr<WasmEngine> WasmEngine::GetWasmEngine() {
if (FLAG_wasm_shared_engine) return *GetSharedWasmEngine();
return std::make_shared<WasmEngine>();
}
// {max_mem_pages} is declared in wasm-limits.h.
uint32_t max_mem_pages() {
STATIC_ASSERT(kV8MaxWasmMemoryPages <= kMaxUInt32);
return std::min(uint32_t{kV8MaxWasmMemoryPages}, FLAG_wasm_max_mem_pages);
}
// {max_table_init_entries} is declared in wasm-limits.h.
uint32_t max_table_init_entries() {
return std::min(uint32_t{kV8MaxWasmTableInitEntries},
FLAG_wasm_max_table_size);
}
#undef TRACE_CODE_GC
} // namespace wasm
} // namespace internal
} // namespace v8