The Tor Browser: js/src/jsworkers.h@b8a032363ba2 (annotated)

js/src/jsworkers.h@b8a032363ba2 (annotated)

js/src/jsworkers.h

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  * vim: set ts=8 sts=4 et sw=4 tw=99:
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /*
  * Definitions for managing off-main-thread work using a shared, per runtime
  * worklist. Worklist items are engine internal, and are distinct from e.g.
  * web workers.
  */
 #ifndef jsworkers_h
 #define jsworkers_h
 #include "mozilla/GuardObjects.h"
 #include "mozilla/PodOperations.h"
 #include "jscntxt.h"
 #include "jslock.h"
 #include "frontend/TokenStream.h"
 #include "jit/Ion.h"
 namespace js {
 struct WorkerThread;
 struct AsmJSParallelTask;
 struct ParseTask;
 namespace jit {
   class IonBuilder;
 }
 #ifdef JS_THREADSAFE
 // Per-process state for off thread work items.
 class GlobalWorkerThreadState
 {
   public:
     // Number of CPUs to treat this machine as having when creating threads.
     // May be accessed without locking.
     size_t cpuCount;
     // Number of threads to create. May be accessed without locking.
     size_t threadCount;
     typedef Vector<jit::IonBuilder*, 0, SystemAllocPolicy> IonBuilderVector;
     typedef Vector<AsmJSParallelTask*, 0, SystemAllocPolicy> AsmJSParallelTaskVector;
     typedef Vector<ParseTask*, 0, SystemAllocPolicy> ParseTaskVector;
     typedef Vector<SourceCompressionTask*, 0, SystemAllocPolicy> SourceCompressionTaskVector;
     // List of available threads, or null if the thread state has not been initialized.
     WorkerThread *threads;
   private:
     // The lists below are all protected by |lock|.
     // Ion compilation worklist and finished jobs.
     IonBuilderVector ionWorklist_, ionFinishedList_;
     // AsmJS worklist and finished jobs.
     //
     // Simultaneous AsmJS compilations all service the same AsmJS module.
     // The main thread must pick up finished optimizations and perform codegen.
     // |asmJSCompilationInProgress| is used to avoid triggering compilations
     // for more than one module at a time.
     AsmJSParallelTaskVector asmJSWorklist_, asmJSFinishedList_;
   public:
     // For now, only allow a single parallel asm.js compilation to happen at a
     // time. This avoids race conditions on asmJSWorklist/asmJSFinishedList/etc.
     mozilla::Atomic<bool> asmJSCompilationInProgress;
   private:
     // Script parsing/emitting worklist and finished jobs.
     ParseTaskVector parseWorklist_, parseFinishedList_;
     // Parse tasks waiting for an atoms-zone GC to complete.
     ParseTaskVector parseWaitingOnGC_;
     // Source compression worklist.
     SourceCompressionTaskVector compressionWorklist_;
   public:
     GlobalWorkerThreadState();
     void ensureInitialized();
     void finish();
     void lock();
     void unlock();
 # ifdef DEBUG
     bool isLocked();
 # endif
     enum CondVar {
         // For notifying threads waiting for work that they may be able to make progress.
         CONSUMER,
         // For notifying threads doing work that they may be able to make progress.
         PRODUCER
     };
     void wait(CondVar which, uint32_t timeoutMillis = 0);
     void notifyAll(CondVar which);
     void notifyOne(CondVar which);
     // Helper method for removing items from the vectors below while iterating over them.
     template <typename T>
     void remove(T &vector, size_t *index)
     {
         vector[(*index)--] = vector.back();
         vector.popBack();
     }
     IonBuilderVector &ionWorklist() {
         JS_ASSERT(isLocked());
         return ionWorklist_;
     }
     IonBuilderVector &ionFinishedList() {
         JS_ASSERT(isLocked());
         return ionFinishedList_;
     }
     AsmJSParallelTaskVector &asmJSWorklist() {
         JS_ASSERT(isLocked());
         return asmJSWorklist_;
     }
     AsmJSParallelTaskVector &asmJSFinishedList() {
         JS_ASSERT(isLocked());
         return asmJSFinishedList_;
     }
     ParseTaskVector &parseWorklist() {
         JS_ASSERT(isLocked());
         return parseWorklist_;
     }
     ParseTaskVector &parseFinishedList() {
         JS_ASSERT(isLocked());
         return parseFinishedList_;
     }
     ParseTaskVector &parseWaitingOnGC() {
         JS_ASSERT(isLocked());
         return parseWaitingOnGC_;
     }
     SourceCompressionTaskVector &compressionWorklist() {
         JS_ASSERT(isLocked());
         return compressionWorklist_;
     }
     bool canStartAsmJSCompile();
     bool canStartIonCompile();
     bool canStartParseTask();
     bool canStartCompressionTask();
     uint32_t harvestFailedAsmJSJobs() {
         JS_ASSERT(isLocked());
         uint32_t n = numAsmJSFailedJobs;
         numAsmJSFailedJobs = 0;
         return n;
     }
     void noteAsmJSFailure(void *func) {
         // Be mindful to signal the main thread after calling this function.
         JS_ASSERT(isLocked());
         if (!asmJSFailedFunction)
             asmJSFailedFunction = func;
         numAsmJSFailedJobs++;
     }
     bool asmJSWorkerFailed() const {
         return bool(numAsmJSFailedJobs);
     }
     void resetAsmJSFailureState() {
         numAsmJSFailedJobs = 0;
         asmJSFailedFunction = nullptr;
     }
     void *maybeAsmJSFailedFunction() const {
         return asmJSFailedFunction;
     }
     JSScript *finishParseTask(JSContext *maybecx, JSRuntime *rt, void *token);
     bool compressionInProgress(SourceCompressionTask *task);
     SourceCompressionTask *compressionTaskForSource(ScriptSource *ss);
   private:
     /*
      * Lock protecting all mutable shared state accessed by helper threads, and
      * used by all condition variables.
      */
     PRLock *workerLock;
 # ifdef DEBUG
     PRThread *lockOwner;
 # endif
     /* Condvars for threads waiting/notifying each other. */
     PRCondVar *consumerWakeup;
     PRCondVar *producerWakeup;
     /*
      * Number of AsmJS workers that encountered failure for the active module.
      * Their parent is logically the main thread, and this number serves for harvesting.
      */
     uint32_t numAsmJSFailedJobs;
     /*
      * Function index |i| in |Module.function(i)| of first failed AsmJS function.
      * -1 if no function has failed.
      */
     void *asmJSFailedFunction;
 };
 static inline GlobalWorkerThreadState &
 WorkerThreadState()
 {
     extern GlobalWorkerThreadState gWorkerThreadState;
     return gWorkerThreadState;
 }
 /* Individual helper thread, one allocated per core. */
 struct WorkerThread
 {
     mozilla::Maybe<PerThreadData> threadData;
     PRThread *thread;
     /* Indicate to an idle thread that it should finish executing. */
     bool terminate;
     /* Any builder currently being compiled by Ion on this thread. */
     jit::IonBuilder *ionBuilder;
     /* Any AsmJS data currently being optimized by Ion on this thread. */
     AsmJSParallelTask *asmData;
     /* Any source being parsed/emitted on this thread. */
     ParseTask *parseTask;
     /* Any source being compressed on this thread. */
     SourceCompressionTask *compressionTask;
     bool idle() const {
         return !ionBuilder && !asmData && !parseTask && !compressionTask;
     }
     void destroy();
     void handleAsmJSWorkload();
     void handleIonWorkload();
     void handleParseWorkload();
     void handleCompressionWorkload();
     static void ThreadMain(void *arg);
     void threadLoop();
 };
 #endif /* JS_THREADSAFE */
 /* Methods for interacting with worker threads. */
 // Initialize worker threads unless already initialized.
 void
 EnsureWorkerThreadsInitialized(ExclusiveContext *cx);
 // This allows the JS shell to override GetCPUCount() when passed the
 // --thread-count=N option.
 void
 SetFakeCPUCount(size_t count);
 #ifdef JS_ION
 /* Perform MIR optimization and LIR generation on a single function. */
 bool
 StartOffThreadAsmJSCompile(ExclusiveContext *cx, AsmJSParallelTask *asmData);
 /*
  * Schedule an Ion compilation for a script, given a builder which has been
  * generated and read everything needed from the VM state.
  */
 bool
 StartOffThreadIonCompile(JSContext *cx, jit::IonBuilder *builder);
 #endif // JS_ION
 /*
  * Cancel a scheduled or in progress Ion compilation for script. If script is
  * nullptr, all compilations for the compartment are cancelled.
  */
 void
 CancelOffThreadIonCompile(JSCompartment *compartment, JSScript *script);
 /* Cancel all scheduled, in progress or finished parses for runtime. */
 void
 CancelOffThreadParses(JSRuntime *runtime);
 /*
  * Start a parse/emit cycle for a stream of source. The characters must stay
  * alive until the compilation finishes.
  */
 bool
 StartOffThreadParseScript(JSContext *cx, const ReadOnlyCompileOptions &options,
                           const jschar *chars, size_t length,
                           JS::OffThreadCompileCallback callback, void *callbackData);
 /*
  * Called at the end of GC to enqueue any Parse tasks that were waiting on an
  * atoms-zone GC to finish.
  */
 void
 EnqueuePendingParseTasksAfterGC(JSRuntime *rt);
 /* Start a compression job for the specified token. */
 bool
 StartOffThreadCompression(ExclusiveContext *cx, SourceCompressionTask *task);
 class AutoLockWorkerThreadState
 {
     MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
 #ifdef JS_THREADSAFE
   public:
     AutoLockWorkerThreadState(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM)
     {
         MOZ_GUARD_OBJECT_NOTIFIER_INIT;
         WorkerThreadState().lock();
     }
     ~AutoLockWorkerThreadState() {
         WorkerThreadState().unlock();
     }
 #else
   public:
     AutoLockWorkerThreadState(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM)
     {
         MOZ_GUARD_OBJECT_NOTIFIER_INIT;
     }
 #endif
 };
 class AutoUnlockWorkerThreadState
 {
     MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
   public:
     AutoUnlockWorkerThreadState(MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM)
     {
         MOZ_GUARD_OBJECT_NOTIFIER_INIT;
 #ifdef JS_THREADSAFE
         WorkerThreadState().unlock();
 #endif
     }
     ~AutoUnlockWorkerThreadState()
     {
 #ifdef JS_THREADSAFE
         WorkerThreadState().lock();
 #endif
     }
 };
 #ifdef JS_ION
 struct AsmJSParallelTask
 {
     JSRuntime *runtime;     // Associated runtime.
     LifoAlloc lifo;         // Provider of all heap memory used for compilation.
     void *func;             // Really, a ModuleCompiler::Func*
     jit::MIRGenerator *mir; // Passed from main thread to worker.
     jit::LIRGraph *lir;     // Passed from worker to main thread.
     unsigned compileTime;
     AsmJSParallelTask(size_t defaultChunkSize)
       : runtime(nullptr), lifo(defaultChunkSize), func(nullptr), mir(nullptr), lir(nullptr), compileTime(0)
     { }
     void init(JSRuntime *rt, void *func, jit::MIRGenerator *mir) {
         this->runtime = rt;
         this->func = func;
         this->mir = mir;
         this->lir = nullptr;
     }
 };
 #endif
 struct ParseTask
 {
     ExclusiveContext *cx;
     OwningCompileOptions options;
     const jschar *chars;
     size_t length;
     LifoAlloc alloc;
     // Rooted pointer to the global object used by 'cx'.
     PersistentRootedObject exclusiveContextGlobal;
     // Saved GC-managed CompileOptions fields that will populate slots in
     // the ScriptSourceObject. We create the ScriptSourceObject in the
     // compilation's temporary compartment, so storing these values there
     // at that point would create cross-compartment references. Instead we
     // hold them here, and install them after merging the compartments.
     PersistentRootedObject optionsElement;
     PersistentRootedScript optionsIntroductionScript;
     // Callback invoked off the main thread when the parse finishes.
     JS::OffThreadCompileCallback callback;
     void *callbackData;
     // Holds the final script between the invocation of the callback and the
     // point where FinishOffThreadScript is called, which will destroy the
     // ParseTask.
     JSScript *script;
     // Any errors or warnings produced during compilation. These are reported
     // when finishing the script.
     Vector<frontend::CompileError *> errors;
     bool overRecursed;
     ParseTask(ExclusiveContext *cx, JSObject *exclusiveContextGlobal,
               JSContext *initCx, const jschar *chars, size_t length,
               JS::OffThreadCompileCallback callback, void *callbackData);
     bool init(JSContext *cx, const ReadOnlyCompileOptions &options);
     void activate(JSRuntime *rt);
     void finish();
     bool runtimeMatches(JSRuntime *rt) {
         return exclusiveContextGlobal->runtimeFromAnyThread() == rt;
     }
     ~ParseTask();
 };
 #ifdef JS_THREADSAFE
 // Return whether, if a new parse task was started, it would need to wait for
 // an in-progress GC to complete before starting.
 extern bool
 OffThreadParsingMustWaitForGC(JSRuntime *rt);
 #endif
 // Compression tasks are allocated on the stack by their triggering thread,
 // which will block on the compression completing as the task goes out of scope
 // to ensure it completes at the required time.
 struct SourceCompressionTask
 {
     friend class ScriptSource;
 #ifdef JS_THREADSAFE
     // Thread performing the compression.
     WorkerThread *workerThread;
 #endif
   private:
     // Context from the triggering thread. Don't use this off thread!
     ExclusiveContext *cx;
     ScriptSource *ss;
     const jschar *chars;
     bool oom;
     // Atomic flag to indicate to a worker thread that it should abort
     // compression on the source.
     mozilla::Atomic<bool, mozilla::Relaxed> abort_;
   public:
     explicit SourceCompressionTask(ExclusiveContext *cx)
       : cx(cx), ss(nullptr), chars(nullptr), oom(false), abort_(false)
     {
 #ifdef JS_THREADSAFE
         workerThread = nullptr;
 #endif
     }
     ~SourceCompressionTask()
     {
         complete();
     }
     bool work();
     bool complete();
     void abort() { abort_ = true; }
     bool active() const { return !!ss; }
     ScriptSource *source() { return ss; }
     const jschar *uncompressedChars() { return chars; }
     void setOOM() { oom = true; }
 };
 } /* namespace js */
 #endif /* jsworkers_h */

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js/src/jsworkers.h@b8a032363ba2 (annotated)

js/src/jsworkers.h