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/* -*- 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-runtime state for off thread work items. */
class WorkerThreadState
{
public:
/* Available threads. */
WorkerThread *threads;
size_t numThreads;
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
};
/* Shared worklist for Ion worker threads. */
Vector<jit::IonBuilder*, 0, SystemAllocPolicy> ionWorklist;
/* Worklist for AsmJS worker threads. */
Vector<AsmJSParallelTask*, 0, SystemAllocPolicy> asmJSWorklist;
/*
* Finished list for AsmJS worker threads.
* Simultaneous AsmJS compilations all service the same AsmJS module.
* The main thread must pick up finished optimizations and perform codegen.
*/
Vector<AsmJSParallelTask*, 0, SystemAllocPolicy> asmJSFinishedList;
/*
* 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<uint32_t> asmJSCompilationInProgress;
/* Shared worklist for parsing/emitting scripts on worker threads. */
Vector<ParseTask*, 0, SystemAllocPolicy> parseWorklist, parseFinishedList;
/* Main-thread-only list of parse tasks waiting for an atoms-zone GC to complete. */
Vector<ParseTask*, 0, SystemAllocPolicy> parseWaitingOnGC;
/* Worklist for source compression worker threads. */
Vector<SourceCompressionTask *, 0, SystemAllocPolicy> compressionWorklist;
WorkerThreadState(JSRuntime *rt) {
mozilla::PodZero(this);
runtime = rt;
}
~WorkerThreadState();
bool init();
void cleanup();
void lock();
void unlock();
# ifdef DEBUG
bool isLocked();
# endif
void wait(CondVar which, uint32_t timeoutMillis = 0);
void notifyAll(CondVar which);
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:
JSRuntime *runtime;
/*
* 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;
};
/* Individual helper thread, one allocated per core. */
struct WorkerThread
{
JSRuntime *runtime;
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(WorkerThreadState &state);
void handleIonWorkload(WorkerThreadState &state);
void handleParseWorkload(WorkerThreadState &state);
void handleCompressionWorkload(WorkerThreadState &state);
static void ThreadMain(void *arg);
void threadLoop();
};
#endif /* JS_THREADSAFE */
/* Methods for interacting with worker threads. */
/* Initialize worker threads unless already initialized. */
bool
EnsureWorkerThreadsInitialized(ExclusiveContext *cx);
#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);
/*
* 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, HandleObject scopeChain,
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);
/* Block until in progress and pending off thread parse jobs have finished. */
void
WaitForOffThreadParsingToFinish(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
WorkerThreadState &state;
public:
AutoLockWorkerThreadState(WorkerThreadState &state
MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
: state(state)
{
MOZ_GUARD_OBJECT_NOTIFIER_INIT;
state.lock();
}
~AutoLockWorkerThreadState() {
state.unlock();
}
#else
public:
AutoLockWorkerThreadState(WorkerThreadState &state
MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
{
MOZ_GUARD_OBJECT_NOTIFIER_INIT;
}
#endif
};
class AutoUnlockWorkerThreadState
{
JSRuntime *rt;
MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
public:
AutoUnlockWorkerThreadState(JSRuntime *rt
MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
: rt(rt)
{
MOZ_GUARD_OBJECT_NOTIFIER_INIT;
#ifdef JS_THREADSAFE
JS_ASSERT(rt->workerThreadState);
rt->workerThreadState->unlock();
#else
(void)this->rt;
#endif
}
~AutoUnlockWorkerThreadState()
{
#ifdef JS_THREADSAFE
rt->workerThreadState->lock();
#endif
}
};
#ifdef JS_ION
struct AsmJSParallelTask
{
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)
: lifo(defaultChunkSize), func(nullptr), mir(nullptr), lir(nullptr), compileTime(0)
{ }
void init(void *func, jit::MIRGenerator *mir) {
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 scope in the target compartment which the
// resulting script will be merged into. This is not safe to use off the
// main thread.
JSObject *scopeChain;
// Rooted pointer to the global object used by 'cx'.
JSObject *exclusiveContextGlobal;
// 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, JSObject *scopeChain,
JS::OffThreadCompileCallback callback, void *callbackData);
bool init(JSContext *cx, const ReadOnlyCompileOptions &options);
void activate(JSRuntime *rt);
~ParseTask();
};
// 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);
// 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.
#ifdef JS_THREADSAFE
mozilla::Atomic<int32_t, mozilla::Relaxed> abort_;
#else
int32_t abort_;
#endif
public:
explicit SourceCompressionTask(ExclusiveContext *cx)
: cx(cx), ss(nullptr), chars(nullptr), oom(false), abort_(0)
{
#ifdef JS_THREADSAFE
workerThread = nullptr;
#endif
}
~SourceCompressionTask()
{
complete();
}
bool compress();
bool complete();
void abort() { abort_ = 1; }
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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