v8_platform.cc 16 KB

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  1. // Copyright 2014 The Chromium Authors. All rights reserved.
  2. // Use of this source code is governed by a BSD-style license that can be
  3. // found in the LICENSE file.
  4. #include "gin/public/v8_platform.h"
  5. #include <algorithm>
  6. #include "base/bind.h"
  7. #include "base/bit_cast.h"
  8. #include "base/check_op.h"
  9. #include "base/debug/stack_trace.h"
  10. #include "base/location.h"
  11. #include "base/memory/nonscannable_memory.h"
  12. #include "base/memory/raw_ptr.h"
  13. #include "base/rand_util.h"
  14. #include "base/system/sys_info.h"
  15. #include "base/task/post_job.h"
  16. #include "base/task/task_traits.h"
  17. #include "base/task/thread_pool.h"
  18. #include "base/task/thread_pool/thread_pool_instance.h"
  19. #include "base/trace_event/trace_event.h"
  20. #include "base/tracing_buildflags.h"
  21. #include "build/build_config.h"
  22. #include "gin/per_isolate_data.h"
  23. #include "v8_platform_page_allocator.h"
  24. namespace gin {
  25. namespace {
  26. base::LazyInstance<V8Platform>::Leaky g_v8_platform = LAZY_INSTANCE_INITIALIZER;
  27. constexpr base::TaskTraits kLowPriorityTaskTraits = {
  28. base::TaskPriority::BEST_EFFORT};
  29. constexpr base::TaskTraits kDefaultTaskTraits = {
  30. base::TaskPriority::USER_VISIBLE};
  31. constexpr base::TaskTraits kBlockingTaskTraits = {
  32. base::TaskPriority::USER_BLOCKING};
  33. void PrintStackTrace() {
  34. base::debug::StackTrace trace;
  35. trace.Print();
  36. }
  37. class ConvertableToTraceFormatWrapper final
  38. : public base::trace_event::ConvertableToTraceFormat {
  39. public:
  40. explicit ConvertableToTraceFormatWrapper(
  41. std::unique_ptr<v8::ConvertableToTraceFormat> inner)
  42. : inner_(std::move(inner)) {}
  43. ConvertableToTraceFormatWrapper(const ConvertableToTraceFormatWrapper&) =
  44. delete;
  45. ConvertableToTraceFormatWrapper& operator=(
  46. const ConvertableToTraceFormatWrapper&) = delete;
  47. ~ConvertableToTraceFormatWrapper() override = default;
  48. void AppendAsTraceFormat(std::string* out) const final {
  49. inner_->AppendAsTraceFormat(out);
  50. }
  51. private:
  52. std::unique_ptr<v8::ConvertableToTraceFormat> inner_;
  53. };
  54. class EnabledStateObserverImpl final
  55. : public base::trace_event::TraceLog::EnabledStateObserver {
  56. public:
  57. EnabledStateObserverImpl() {
  58. base::trace_event::TraceLog::GetInstance()->AddEnabledStateObserver(this);
  59. }
  60. EnabledStateObserverImpl(const EnabledStateObserverImpl&) = delete;
  61. EnabledStateObserverImpl& operator=(const EnabledStateObserverImpl&) = delete;
  62. ~EnabledStateObserverImpl() override {
  63. base::trace_event::TraceLog::GetInstance()->RemoveEnabledStateObserver(
  64. this);
  65. }
  66. void OnTraceLogEnabled() final {
  67. base::AutoLock lock(mutex_);
  68. for (auto* o : observers_) {
  69. o->OnTraceEnabled();
  70. }
  71. }
  72. void OnTraceLogDisabled() final {
  73. base::AutoLock lock(mutex_);
  74. for (auto* o : observers_) {
  75. o->OnTraceDisabled();
  76. }
  77. }
  78. void AddObserver(v8::TracingController::TraceStateObserver* observer) {
  79. {
  80. base::AutoLock lock(mutex_);
  81. DCHECK(!observers_.count(observer));
  82. observers_.insert(observer);
  83. }
  84. // Fire the observer if recording is already in progress.
  85. if (base::trace_event::TraceLog::GetInstance()->IsEnabled())
  86. observer->OnTraceEnabled();
  87. }
  88. void RemoveObserver(v8::TracingController::TraceStateObserver* observer) {
  89. base::AutoLock lock(mutex_);
  90. DCHECK(observers_.count(observer) == 1);
  91. observers_.erase(observer);
  92. }
  93. private:
  94. base::Lock mutex_;
  95. std::unordered_set<v8::TracingController::TraceStateObserver*> observers_;
  96. };
  97. base::LazyInstance<EnabledStateObserverImpl>::Leaky g_trace_state_dispatcher =
  98. LAZY_INSTANCE_INITIALIZER;
  99. // TODO(skyostil): Deduplicate this with the clamper in Blink.
  100. class TimeClamper {
  101. public:
  102. // As site isolation is enabled on desktop platforms, we can safely provide
  103. // more timing resolution. Jittering is still enabled everywhere.
  104. #if BUILDFLAG(IS_ANDROID)
  105. static constexpr double kResolutionSeconds = 100e-6;
  106. #else
  107. static constexpr double kResolutionSeconds = 5e-6;
  108. #endif
  109. TimeClamper() : secret_(base::RandUint64()) {}
  110. TimeClamper(const TimeClamper&) = delete;
  111. TimeClamper& operator=(const TimeClamper&) = delete;
  112. double ClampTimeResolution(double time_seconds) const {
  113. bool was_negative = false;
  114. if (time_seconds < 0) {
  115. was_negative = true;
  116. time_seconds = -time_seconds;
  117. }
  118. // For each clamped time interval, compute a pseudorandom transition
  119. // threshold. The reported time will either be the start of that interval or
  120. // the next one depending on which side of the threshold |time_seconds| is.
  121. double interval = floor(time_seconds / kResolutionSeconds);
  122. double clamped_time = interval * kResolutionSeconds;
  123. double tick_threshold = ThresholdFor(clamped_time);
  124. if (time_seconds >= tick_threshold)
  125. clamped_time = (interval + 1) * kResolutionSeconds;
  126. if (was_negative)
  127. clamped_time = -clamped_time;
  128. return clamped_time;
  129. }
  130. private:
  131. inline double ThresholdFor(double clamped_time) const {
  132. uint64_t time_hash = MurmurHash3(bit_cast<int64_t>(clamped_time) ^ secret_);
  133. return clamped_time + kResolutionSeconds * ToDouble(time_hash);
  134. }
  135. static inline double ToDouble(uint64_t value) {
  136. // Exponent for double values for [1.0 .. 2.0]
  137. static const uint64_t kExponentBits = uint64_t{0x3FF0000000000000};
  138. static const uint64_t kMantissaMask = uint64_t{0x000FFFFFFFFFFFFF};
  139. uint64_t random = (value & kMantissaMask) | kExponentBits;
  140. return bit_cast<double>(random) - 1;
  141. }
  142. static inline uint64_t MurmurHash3(uint64_t value) {
  143. value ^= value >> 33;
  144. value *= uint64_t{0xFF51AFD7ED558CCD};
  145. value ^= value >> 33;
  146. value *= uint64_t{0xC4CEB9FE1A85EC53};
  147. value ^= value >> 33;
  148. return value;
  149. }
  150. const uint64_t secret_;
  151. };
  152. base::LazyInstance<TimeClamper>::Leaky g_time_clamper =
  153. LAZY_INSTANCE_INITIALIZER;
  154. #if BUILDFLAG(USE_PARTITION_ALLOC)
  155. base::LazyInstance<gin::PageAllocator>::Leaky g_page_allocator =
  156. LAZY_INSTANCE_INITIALIZER;
  157. #endif // BUILDFLAG(USE_PARTITION_ALLOC)
  158. class JobDelegateImpl : public v8::JobDelegate {
  159. public:
  160. explicit JobDelegateImpl(base::JobDelegate* delegate) : delegate_(delegate) {}
  161. JobDelegateImpl() = default;
  162. JobDelegateImpl(const JobDelegateImpl&) = delete;
  163. JobDelegateImpl& operator=(const JobDelegateImpl&) = delete;
  164. // v8::JobDelegate:
  165. bool ShouldYield() override { return delegate_->ShouldYield(); }
  166. void NotifyConcurrencyIncrease() override {
  167. delegate_->NotifyConcurrencyIncrease();
  168. }
  169. uint8_t GetTaskId() override { return delegate_->GetTaskId(); }
  170. bool IsJoiningThread() const override { return delegate_->IsJoiningThread(); }
  171. private:
  172. raw_ptr<base::JobDelegate> delegate_;
  173. };
  174. class JobHandleImpl : public v8::JobHandle {
  175. public:
  176. explicit JobHandleImpl(base::JobHandle handle) : handle_(std::move(handle)) {}
  177. ~JobHandleImpl() override = default;
  178. JobHandleImpl(const JobHandleImpl&) = delete;
  179. JobHandleImpl& operator=(const JobHandleImpl&) = delete;
  180. // v8::JobHandle:
  181. void NotifyConcurrencyIncrease() override {
  182. handle_.NotifyConcurrencyIncrease();
  183. }
  184. bool UpdatePriorityEnabled() const override { return true; }
  185. void UpdatePriority(v8::TaskPriority new_priority) override {
  186. handle_.UpdatePriority(ToBaseTaskPriority(new_priority));
  187. }
  188. void Join() override { handle_.Join(); }
  189. void Cancel() override { handle_.Cancel(); }
  190. void CancelAndDetach() override { handle_.CancelAndDetach(); }
  191. bool IsActive() override { return handle_.IsActive(); }
  192. bool IsValid() override { return !!handle_; }
  193. private:
  194. static base::TaskPriority ToBaseTaskPriority(v8::TaskPriority priority) {
  195. switch (priority) {
  196. case v8::TaskPriority::kBestEffort:
  197. return base::TaskPriority::BEST_EFFORT;
  198. case v8::TaskPriority::kUserVisible:
  199. return base::TaskPriority::USER_VISIBLE;
  200. case v8::TaskPriority::kUserBlocking:
  201. return base::TaskPriority::USER_BLOCKING;
  202. }
  203. }
  204. base::JobHandle handle_;
  205. };
  206. } // namespace
  207. } // namespace gin
  208. // Allow std::unique_ptr<v8::ConvertableToTraceFormat> to be a valid
  209. // initialization value for trace macros.
  210. template <>
  211. struct base::trace_event::TraceValue::Helper<
  212. std::unique_ptr<v8::ConvertableToTraceFormat>> {
  213. static constexpr unsigned char kType = TRACE_VALUE_TYPE_CONVERTABLE;
  214. static inline void SetValue(
  215. TraceValue* v,
  216. std::unique_ptr<v8::ConvertableToTraceFormat> value) {
  217. // NOTE: |as_convertable| is an owning pointer, so using new here
  218. // is acceptable.
  219. v->as_convertable =
  220. new gin::ConvertableToTraceFormatWrapper(std::move(value));
  221. }
  222. };
  223. namespace gin {
  224. class V8Platform::TracingControllerImpl : public v8::TracingController {
  225. public:
  226. TracingControllerImpl() = default;
  227. TracingControllerImpl(const TracingControllerImpl&) = delete;
  228. TracingControllerImpl& operator=(const TracingControllerImpl&) = delete;
  229. ~TracingControllerImpl() override = default;
  230. // TracingController implementation.
  231. #if !BUILDFLAG(USE_PERFETTO_CLIENT_LIBRARY)
  232. const uint8_t* GetCategoryGroupEnabled(const char* name) override {
  233. return TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(name);
  234. }
  235. uint64_t AddTraceEvent(
  236. char phase,
  237. const uint8_t* category_enabled_flag,
  238. const char* name,
  239. const char* scope,
  240. uint64_t id,
  241. uint64_t bind_id,
  242. int32_t num_args,
  243. const char** arg_names,
  244. const uint8_t* arg_types,
  245. const uint64_t* arg_values,
  246. std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
  247. unsigned int flags) override {
  248. base::trace_event::TraceArguments args(
  249. num_args, arg_names, arg_types,
  250. reinterpret_cast<const unsigned long long*>(arg_values),
  251. arg_convertables);
  252. DCHECK_LE(num_args, 2);
  253. base::trace_event::TraceEventHandle handle =
  254. TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_BIND_ID(
  255. phase, category_enabled_flag, name, scope, id, bind_id, &args,
  256. flags);
  257. uint64_t result;
  258. memcpy(&result, &handle, sizeof(result));
  259. return result;
  260. }
  261. uint64_t AddTraceEventWithTimestamp(
  262. char phase,
  263. const uint8_t* category_enabled_flag,
  264. const char* name,
  265. const char* scope,
  266. uint64_t id,
  267. uint64_t bind_id,
  268. int32_t num_args,
  269. const char** arg_names,
  270. const uint8_t* arg_types,
  271. const uint64_t* arg_values,
  272. std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
  273. unsigned int flags,
  274. int64_t timestampMicroseconds) override {
  275. base::trace_event::TraceArguments args(
  276. num_args, arg_names, arg_types,
  277. reinterpret_cast<const unsigned long long*>(arg_values),
  278. arg_convertables);
  279. DCHECK_LE(num_args, 2);
  280. base::TimeTicks timestamp =
  281. base::TimeTicks() + base::Microseconds(timestampMicroseconds);
  282. base::trace_event::TraceEventHandle handle =
  283. TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
  284. phase, category_enabled_flag, name, scope, id, bind_id,
  285. TRACE_EVENT_API_CURRENT_THREAD_ID, timestamp, &args, flags);
  286. uint64_t result;
  287. memcpy(&result, &handle, sizeof(result));
  288. return result;
  289. }
  290. void UpdateTraceEventDuration(const uint8_t* category_enabled_flag,
  291. const char* name,
  292. uint64_t handle) override {
  293. base::trace_event::TraceEventHandle traceEventHandle;
  294. memcpy(&traceEventHandle, &handle, sizeof(handle));
  295. TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(category_enabled_flag, name,
  296. traceEventHandle);
  297. }
  298. #endif // !BUILDFLAG(USE_PERFETTO_CLIENT_LIBRARY)
  299. void AddTraceStateObserver(TraceStateObserver* observer) override {
  300. g_trace_state_dispatcher.Get().AddObserver(observer);
  301. }
  302. void RemoveTraceStateObserver(TraceStateObserver* observer) override {
  303. g_trace_state_dispatcher.Get().RemoveObserver(observer);
  304. }
  305. };
  306. // static
  307. V8Platform* V8Platform::Get() { return g_v8_platform.Pointer(); }
  308. V8Platform::V8Platform() : tracing_controller_(new TracingControllerImpl) {}
  309. V8Platform::~V8Platform() = default;
  310. #if BUILDFLAG(USE_PARTITION_ALLOC)
  311. PageAllocator* V8Platform::GetPageAllocator() {
  312. return g_page_allocator.Pointer();
  313. }
  314. void V8Platform::OnCriticalMemoryPressure() {
  315. // We only have a reservation on 32-bit Windows systems.
  316. // TODO(bbudge) Make the #if's in BlinkInitializer match.
  317. #if BUILDFLAG(IS_WIN) && defined(ARCH_CPU_32_BITS)
  318. base::ReleaseReservation();
  319. #endif
  320. }
  321. v8::ZoneBackingAllocator* V8Platform::GetZoneBackingAllocator() {
  322. static struct Allocator final : v8::ZoneBackingAllocator {
  323. MallocFn GetMallocFn() const override {
  324. return &base::AllocNonQuarantinable;
  325. }
  326. FreeFn GetFreeFn() const override { return &base::FreeNonQuarantinable; }
  327. } allocator;
  328. return &allocator;
  329. }
  330. #endif // BUILDFLAG(USE_PARTITION_ALLOC)
  331. std::shared_ptr<v8::TaskRunner> V8Platform::GetForegroundTaskRunner(
  332. v8::Isolate* isolate) {
  333. PerIsolateData* data = PerIsolateData::From(isolate);
  334. return data->task_runner();
  335. }
  336. int V8Platform::NumberOfWorkerThreads() {
  337. // V8Platform assumes the scheduler uses the same set of workers for default
  338. // and user blocking tasks.
  339. const int num_foreground_workers =
  340. base::ThreadPoolInstance::Get()
  341. ->GetMaxConcurrentNonBlockedTasksWithTraitsDeprecated(
  342. kDefaultTaskTraits);
  343. DCHECK_EQ(num_foreground_workers,
  344. base::ThreadPoolInstance::Get()
  345. ->GetMaxConcurrentNonBlockedTasksWithTraitsDeprecated(
  346. kBlockingTaskTraits));
  347. return std::max(1, num_foreground_workers);
  348. }
  349. void V8Platform::CallOnWorkerThread(std::unique_ptr<v8::Task> task) {
  350. base::ThreadPool::PostTask(FROM_HERE, kDefaultTaskTraits,
  351. base::BindOnce(&v8::Task::Run, std::move(task)));
  352. }
  353. void V8Platform::CallBlockingTaskOnWorkerThread(
  354. std::unique_ptr<v8::Task> task) {
  355. base::ThreadPool::PostTask(FROM_HERE, kBlockingTaskTraits,
  356. base::BindOnce(&v8::Task::Run, std::move(task)));
  357. }
  358. void V8Platform::CallLowPriorityTaskOnWorkerThread(
  359. std::unique_ptr<v8::Task> task) {
  360. base::ThreadPool::PostTask(FROM_HERE, kLowPriorityTaskTraits,
  361. base::BindOnce(&v8::Task::Run, std::move(task)));
  362. }
  363. void V8Platform::CallDelayedOnWorkerThread(std::unique_ptr<v8::Task> task,
  364. double delay_in_seconds) {
  365. base::ThreadPool::PostDelayedTask(
  366. FROM_HERE, kDefaultTaskTraits,
  367. base::BindOnce(&v8::Task::Run, std::move(task)),
  368. base::Seconds(delay_in_seconds));
  369. }
  370. std::unique_ptr<v8::JobHandle> V8Platform::PostJob(
  371. v8::TaskPriority priority,
  372. std::unique_ptr<v8::JobTask> job_task) {
  373. base::TaskTraits task_traits;
  374. switch (priority) {
  375. case v8::TaskPriority::kBestEffort:
  376. task_traits = kLowPriorityTaskTraits;
  377. break;
  378. case v8::TaskPriority::kUserVisible:
  379. task_traits = kDefaultTaskTraits;
  380. break;
  381. case v8::TaskPriority::kUserBlocking:
  382. task_traits = kBlockingTaskTraits;
  383. break;
  384. }
  385. // Ownership of |job_task| is assumed by |worker_task|, while
  386. // |max_concurrency_callback| uses an unretained pointer.
  387. auto* job_task_ptr = job_task.get();
  388. auto handle =
  389. base::PostJob(FROM_HERE, task_traits,
  390. base::BindRepeating(
  391. [](const std::unique_ptr<v8::JobTask>& job_task,
  392. base::JobDelegate* delegate) {
  393. JobDelegateImpl delegate_impl(delegate);
  394. job_task->Run(&delegate_impl);
  395. },
  396. std::move(job_task)),
  397. base::BindRepeating(
  398. [](v8::JobTask* job_task, size_t worker_count) {
  399. return job_task->GetMaxConcurrency(worker_count);
  400. },
  401. base::Unretained(job_task_ptr)));
  402. return std::make_unique<JobHandleImpl>(std::move(handle));
  403. }
  404. bool V8Platform::IdleTasksEnabled(v8::Isolate* isolate) {
  405. return PerIsolateData::From(isolate)->task_runner()->IdleTasksEnabled();
  406. }
  407. double V8Platform::MonotonicallyIncreasingTime() {
  408. return base::TimeTicks::Now().ToInternalValue() /
  409. static_cast<double>(base::Time::kMicrosecondsPerSecond);
  410. }
  411. double V8Platform::CurrentClockTimeMillis() {
  412. double now_seconds = base::Time::Now().ToJsTime() / 1000;
  413. return g_time_clamper.Get().ClampTimeResolution(now_seconds) * 1000;
  414. }
  415. v8::TracingController* V8Platform::GetTracingController() {
  416. return tracing_controller_.get();
  417. }
  418. v8::Platform::StackTracePrinter V8Platform::GetStackTracePrinter() {
  419. return PrintStackTrace;
  420. }
  421. } // namespace gin