The Tor Browser: js/src/vm/ForkJoin.cpp@6474c204b198 (annotated)

js/src/vm/ForkJoin.cpp@6474c204b198 (annotated)

js/src/vm/ForkJoin.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- 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/. */
 #if defined(XP_WIN)
 # include <io.h>     // for isatty()
 #else
 # include <unistd.h> // for isatty()
 #endif
 #include "vm/ForkJoin.h"
 #include "mozilla/ThreadLocal.h"
 #include "jscntxt.h"
 #include "jslock.h"
 #include "jsprf.h"
 #include "builtin/TypedObject.h"
 #ifdef JS_THREADSAFE
 # include "jit/BaselineJIT.h"
 # include "vm/Monitor.h"
 #endif
 #if defined(JS_THREADSAFE) && defined(JS_ION)
 # include "jit/JitCommon.h"
 # ifdef DEBUG
 #  include "jit/Ion.h"
 #  include "jit/JitCompartment.h"
 #  include "jit/MIR.h"
 #  include "jit/MIRGraph.h"
 # endif
 #endif // THREADSAFE && ION
 #include "vm/Interpreter-inl.h"
 using namespace js;
 using namespace js::parallel;
 using namespace js::jit;
 using mozilla::ThreadLocal;
 ///////////////////////////////////////////////////////////////////////////
 // Degenerate configurations
 //
 // When JS_THREADSAFE or JS_ION is not defined, we simply run the
 // |func| callback sequentially.  We also forego the feedback
 // altogether.
 static bool
 ExecuteSequentially(JSContext *cx_, HandleValue funVal, uint16_t *sliceStart,
                     uint16_t sliceEnd);
 #if !defined(JS_THREADSAFE) || !defined(JS_ION)
 bool
 js::ForkJoin(JSContext *cx, CallArgs &args)
 {
     RootedValue argZero(cx, args[0]);
     uint16_t sliceStart = uint16_t(args[1].toInt32());
     uint16_t sliceEnd = uint16_t(args[2].toInt32());
     if (!ExecuteSequentially(cx, argZero, &sliceStart, sliceEnd))
         return false;
     MOZ_ASSERT(sliceStart == sliceEnd);
     return true;
 }
 JSContext *
 ForkJoinContext::acquireJSContext()
 {
     return nullptr;
 }
 void
 ForkJoinContext::releaseJSContext()
 {
 }
 bool
 ForkJoinContext::isMainThread() const
 {
     return true;
 }
 JSRuntime *
 ForkJoinContext::runtime()
 {
     MOZ_ASSUME_UNREACHABLE("Not THREADSAFE build");
 }
 bool
 ForkJoinContext::check()
 {
     MOZ_ASSUME_UNREACHABLE("Not THREADSAFE build");
 }
 void
 ForkJoinContext::requestGC(JS::gcreason::Reason reason)
 {
     MOZ_ASSUME_UNREACHABLE("Not THREADSAFE build");
 }
 void
 ForkJoinContext::requestZoneGC(JS::Zone *zone, JS::gcreason::Reason reason)
 {
     MOZ_ASSUME_UNREACHABLE("Not THREADSAFE build");
 }
 bool
 ForkJoinContext::setPendingAbortFatal(ParallelBailoutCause cause)
 {
     MOZ_ASSUME_UNREACHABLE("Not THREADSAFE build");
     return false;
 }
 void
 ParallelBailoutRecord::setCause(ParallelBailoutCause cause,
                                 JSScript *outermostScript,
                                 JSScript *currentScript,
                                 jsbytecode *currentPc)
 {
     MOZ_ASSUME_UNREACHABLE("Not THREADSAFE build");
 }
 void
 js::ParallelBailoutRecord::updateCause(ParallelBailoutCause cause,
                                        JSScript *outermostScript,
                                        JSScript *currentScript,
                                        jsbytecode *currentPc)
 {
     MOZ_ASSUME_UNREACHABLE("Not THREADSAFE build");
 }
 void
 ParallelBailoutRecord::addTrace(JSScript *script,
                                 jsbytecode *pc)
 {
     MOZ_ASSUME_UNREACHABLE("Not THREADSAFE build");
 }
 bool
 js::InExclusiveParallelSection()
 {
     return false;
 }
 bool
 js::ParallelTestsShouldPass(JSContext *cx)
 {
     return false;
 }
 bool
 js::intrinsic_SetForkJoinTargetRegion(JSContext *cx, unsigned argc, Value *vp)
 {
     return true;
 }
 static bool
 intrinsic_SetForkJoinTargetRegionPar(ForkJoinContext *cx, unsigned argc, Value *vp)
 {
     return true;
 }
 JS_JITINFO_NATIVE_PARALLEL(js::intrinsic_SetForkJoinTargetRegionInfo,
                            intrinsic_SetForkJoinTargetRegionPar);
 bool
 js::intrinsic_ClearThreadLocalArenas(JSContext *cx, unsigned argc, Value *vp)
 {
     return true;
 }
 static bool
 intrinsic_ClearThreadLocalArenasPar(ForkJoinContext *cx, unsigned argc, Value *vp)
 {
     return true;
 }
 JS_JITINFO_NATIVE_PARALLEL(js::intrinsic_ClearThreadLocalArenasInfo,
                            intrinsic_ClearThreadLocalArenasPar);
 #endif // !JS_THREADSAFE || !JS_ION
 ///////////////////////////////////////////////////////////////////////////
 // All configurations
 //
 // Some code that is shared between degenerate and parallel configurations.
 static bool
 ExecuteSequentially(JSContext *cx, HandleValue funVal, uint16_t *sliceStart,
                     uint16_t sliceEnd)
 {
     FastInvokeGuard fig(cx, funVal);
     InvokeArgs &args = fig.args();
     if (!args.init(3))
         return false;
     args.setCallee(funVal);
     args.setThis(UndefinedValue());
     args[0].setInt32(0);
     args[1].setInt32(*sliceStart);
     args[2].setInt32(sliceEnd);
     if (!fig.invoke(cx))
         return false;
     *sliceStart = (uint16_t)(args.rval().toInt32());
     return true;
 }
 ThreadLocal<ForkJoinContext*> ForkJoinContext::tlsForkJoinContext;
 /* static */ bool
 ForkJoinContext::initialize()
 {
     if (!tlsForkJoinContext.initialized()) {
         if (!tlsForkJoinContext.init())
             return false;
     }
     return true;
 }
 ///////////////////////////////////////////////////////////////////////////
 // Parallel configurations
 //
 // The remainder of this file is specific to cases where both
 // JS_THREADSAFE and JS_ION are enabled.
 #if defined(JS_THREADSAFE) && defined(JS_ION)
 ///////////////////////////////////////////////////////////////////////////
 // Class Declarations and Function Prototypes
 namespace js {
 // When writing tests, it is often useful to specify different modes
 // of operation.
 enum ForkJoinMode {
     // WARNING: If you change this enum, you MUST update
     // ForkJoinMode() in Utilities.js
     // The "normal" behavior: attempt parallel, fallback to
     // sequential.  If compilation is ongoing in a helper thread, then
     // run sequential warmup iterations in the meantime. If those
     // iterations wind up completing all the work, just abort.
     ForkJoinModeNormal,
     // Like normal, except that we will keep running warmup iterations
     // until compilations are complete, even if there is no more work
     // to do. This is useful in tests as a "setup" run.
     ForkJoinModeCompile,
     // Requires that compilation has already completed. Expects parallel
     // execution to proceed without a hitch. (Reports an error otherwise)
     ForkJoinModeParallel,
     // Requires that compilation has already completed. Expects
     // parallel execution to bailout once but continue after that without
     // further bailouts. (Reports an error otherwise)
     ForkJoinModeRecover,
     // Expects all parallel executions to yield a bailout.  If this is not
     // the case, reports an error.
     ForkJoinModeBailout,
     NumForkJoinModes
 };
 class ForkJoinOperation
 {
   public:
     // For tests, make sure to keep this in sync with minItemsTestingThreshold.
     static const uint32_t MAX_BAILOUTS = 3;
     uint32_t bailouts;
     // Information about the bailout:
     ParallelBailoutCause bailoutCause;
     RootedScript bailoutScript;
     jsbytecode *bailoutBytecode;
     ForkJoinOperation(JSContext *cx, HandleFunction fun, uint16_t sliceStart,
                       uint16_t sliceEnd, ForkJoinMode mode);
     ExecutionStatus apply();
   private:
     // Most of the functions involved in managing the parallel
     // compilation follow a similar control-flow. They return RedLight
     // if they have either encountered a fatal error or completed the
     // execution, such that no further work is needed. In that event,
     // they take an `ExecutionStatus*` which they use to report
     // whether execution was successful or not. If the function
     // returns `GreenLight`, then the parallel operation is not yet
     // fully completed, so the state machine should carry on.
     enum TrafficLight {
         RedLight,
         GreenLight
     };
     struct WorklistData {
         // True if we enqueued the callees from the ion-compiled
         // version of this entry
         bool calleesEnqueued;
         // Last record useCount; updated after warmup
         // iterations;
         uint32_t useCount;
         // Number of continuous "stalls" --- meaning warmups
         // where useCount did not increase.
         uint32_t stallCount;
         void reset() {
             calleesEnqueued = false;
             useCount = 0;
             stallCount = 0;
         }
     };
     JSContext *cx_;
     HandleFunction fun_;
     uint16_t sliceStart_;
     uint16_t sliceEnd_;
     Vector<ParallelBailoutRecord, 16> bailoutRecords_;
     AutoScriptVector worklist_;
     Vector<WorklistData, 16> worklistData_;
     ForkJoinMode mode_;
     TrafficLight enqueueInitialScript(ExecutionStatus *status);
     TrafficLight compileForParallelExecution(ExecutionStatus *status);
     TrafficLight warmupExecution(bool stopIfComplete, ExecutionStatus *status);
     TrafficLight parallelExecution(ExecutionStatus *status);
     TrafficLight sequentialExecution(bool disqualified, ExecutionStatus *status);
     TrafficLight recoverFromBailout(ExecutionStatus *status);
     TrafficLight fatalError(ExecutionStatus *status);
     bool isInitialScript(HandleScript script);
     void determineBailoutCause();
     bool invalidateBailedOutScripts();
     ExecutionStatus sequentialExecution(bool disqualified);
     TrafficLight appendCallTargetsToWorklist(uint32_t index, ExecutionStatus *status);
     TrafficLight appendCallTargetToWorklist(HandleScript script, ExecutionStatus *status);
     bool addToWorklist(HandleScript script);
     inline bool hasScript(Vector<types::RecompileInfo> &scripts, JSScript *script);
 }; // class ForkJoinOperation
 class ForkJoinShared : public ParallelJob, public Monitor
 {
     /////////////////////////////////////////////////////////////////////////
     // Constant fields
     JSContext *const cx_;                  // Current context
     ThreadPool *const threadPool_;         // The thread pool
     HandleFunction fun_;                   // The JavaScript function to execute
     uint16_t sliceStart_;                  // The starting slice id.
     uint16_t sliceEnd_;                    // The ending slice id + 1.
     PRLock *cxLock_;                       // Locks cx_ for parallel VM calls
     ParallelBailoutRecord *const records_; // Bailout records for each worker
     /////////////////////////////////////////////////////////////////////////
     // Per-thread arenas
     //
     // Each worker thread gets an arena to use when allocating.
     Vector<Allocator *, 16> allocators_;
     /////////////////////////////////////////////////////////////////////////
     // Locked Fields
     //
     // Only to be accessed while holding the lock.
     bool gcRequested_;              // True if a worker requested a GC
     JS::gcreason::Reason gcReason_; // Reason given to request GC
     Zone *gcZone_;                  // Zone for GC, or nullptr for full
     /////////////////////////////////////////////////////////////////////////
     // Asynchronous Flags
     //
     // These can be accessed without the lock and are thus atomic.
     // Set to true when parallel execution should abort.
     mozilla::Atomic<bool, mozilla::ReleaseAcquire> abort_;
     // Set to true when a worker bails for a fatal reason.
     mozilla::Atomic<bool, mozilla::ReleaseAcquire> fatal_;
   public:
     ForkJoinShared(JSContext *cx,
                    ThreadPool *threadPool,
                    HandleFunction fun,
                    uint16_t sliceStart,
                    uint16_t sliceEnd,
                    ParallelBailoutRecord *records);
     ~ForkJoinShared();
     bool init();
     ParallelResult execute();
     // Invoked from parallel worker threads:
     virtual bool executeFromWorker(ThreadPoolWorker *worker, uintptr_t stackLimit) MOZ_OVERRIDE;
     // Invoked only from the main thread:
     virtual bool executeFromMainThread(ThreadPoolWorker *worker) MOZ_OVERRIDE;
     // Executes the user-supplied function a worker or the main thread.
     void executePortion(PerThreadData *perThread, ThreadPoolWorker *worker);
     // Moves all the per-thread arenas into the main compartment and processes
     // any pending requests for a GC. This can only safely be invoked on the
     // main thread after the workers have completed.
     void transferArenasToCompartmentAndProcessGCRequests();
     // Requests a GC, either full or specific to a zone.
     void requestGC(JS::gcreason::Reason reason);
     void requestZoneGC(JS::Zone *zone, JS::gcreason::Reason reason);
     // Requests that computation abort.
     void setAbortFlagDueToInterrupt(ForkJoinContext &cx);
     void setAbortFlagAndRequestInterrupt(bool fatal);
     // Set the fatal flag for the next abort.
     void setPendingAbortFatal() { fatal_ = true; }
     JSRuntime *runtime() { return cx_->runtime(); }
     JS::Zone *zone() { return cx_->zone(); }
     JSCompartment *compartment() { return cx_->compartment(); }
     JSContext *acquireJSContext() { PR_Lock(cxLock_); return cx_; }
     void releaseJSContext() { PR_Unlock(cxLock_); }
 };
 class AutoEnterWarmup
 {
     JSRuntime *runtime_;
   public:
     AutoEnterWarmup(JSRuntime *runtime) : runtime_(runtime) { runtime_->forkJoinWarmup++; }
     ~AutoEnterWarmup() { runtime_->forkJoinWarmup--; }
 };
 class AutoSetForkJoinContext
 {
   public:
     AutoSetForkJoinContext(ForkJoinContext *threadCx) {
         ForkJoinContext::tlsForkJoinContext.set(threadCx);
     }
     ~AutoSetForkJoinContext() {
         ForkJoinContext::tlsForkJoinContext.set(nullptr);
     }
 };
 } // namespace js
 ///////////////////////////////////////////////////////////////////////////
 // ForkJoinActivation
 //
 // Takes care of tidying up GC before we enter a fork join section. Also
 // pauses the barrier verifier, as we cannot enter fork join with the runtime
 // or the zone needing barriers.
 ForkJoinActivation::ForkJoinActivation(JSContext *cx)
   : Activation(cx, ForkJoin),
     prevIonTop_(cx->mainThread().ionTop),
     av_(cx->runtime(), false)
 {
     // Note: we do not allow GC during parallel sections.
     // Moreover, we do not wish to worry about making
     // write barriers thread-safe.  Therefore, we guarantee
     // that there is no incremental GC in progress and force
     // a minor GC to ensure no cross-generation pointers get
     // created:
     if (JS::IsIncrementalGCInProgress(cx->runtime())) {
         JS::PrepareForIncrementalGC(cx->runtime());
         JS::FinishIncrementalGC(cx->runtime(), JS::gcreason::API);
     }
     MinorGC(cx->runtime(), JS::gcreason::API);
     cx->runtime()->gcHelperThread.waitBackgroundSweepEnd();
     JS_ASSERT(!cx->runtime()->needsBarrier());
     JS_ASSERT(!cx->zone()->needsBarrier());
 }
 ForkJoinActivation::~ForkJoinActivation()
 {
     cx_->mainThread().ionTop = prevIonTop_;
 }
 ///////////////////////////////////////////////////////////////////////////
 // js::ForkJoin() and ForkJoinOperation class
 //
 // These are the top-level objects that manage the parallel execution.
 // They handle parallel compilation (if necessary), triggering
 // parallel execution, and recovering from bailouts.
 static const char *ForkJoinModeString(ForkJoinMode mode);
 bool
 js::ForkJoin(JSContext *cx, CallArgs &args)
 {
     JS_ASSERT(args.length() == 4); // else the self-hosted code is wrong
     JS_ASSERT(args[0].isObject());
     JS_ASSERT(args[0].toObject().is<JSFunction>());
     JS_ASSERT(args[1].isInt32());
     JS_ASSERT(args[2].isInt32());
     JS_ASSERT(args[3].isInt32());
     JS_ASSERT(args[3].toInt32() < NumForkJoinModes);
     RootedFunction fun(cx, &args[0].toObject().as<JSFunction>());
     uint16_t sliceStart = (uint16_t)(args[1].toInt32());
     uint16_t sliceEnd = (uint16_t)(args[2].toInt32());
     ForkJoinMode mode = (ForkJoinMode)(args[3].toInt32());
     MOZ_ASSERT(sliceStart == args[1].toInt32());
     MOZ_ASSERT(sliceEnd == args[2].toInt32());
     MOZ_ASSERT(sliceStart <= sliceEnd);
     ForkJoinOperation op(cx, fun, sliceStart, sliceEnd, mode);
     ExecutionStatus status = op.apply();
     if (status == ExecutionFatal)
         return false;
     switch (mode) {
       case ForkJoinModeNormal:
       case ForkJoinModeCompile:
         return true;
       case ForkJoinModeParallel:
         if (status == ExecutionParallel && op.bailouts == 0)
             return true;
         break;
       case ForkJoinModeRecover:
         if (status != ExecutionSequential && op.bailouts > 0)
             return true;
         break;
       case ForkJoinModeBailout:
         if (status != ExecutionParallel)
             return true;
         break;
       case NumForkJoinModes:
         break;
     }
     const char *statusString = "?";
     switch (status) {
       case ExecutionSequential: statusString = "seq"; break;
       case ExecutionParallel: statusString = "par"; break;
       case ExecutionWarmup: statusString = "warmup"; break;
       case ExecutionFatal: statusString = "fatal"; break;
     }
     if (ParallelTestsShouldPass(cx)) {
         JS_ReportError(cx, "ForkJoin: mode=%s status=%s bailouts=%d",
                        ForkJoinModeString(mode), statusString, op.bailouts);
         return false;
     }
     return true;
 }
 static const char *
 ForkJoinModeString(ForkJoinMode mode) {
     switch (mode) {
       case ForkJoinModeNormal: return "normal";
       case ForkJoinModeCompile: return "compile";
       case ForkJoinModeParallel: return "parallel";
       case ForkJoinModeRecover: return "recover";
       case ForkJoinModeBailout: return "bailout";
       case NumForkJoinModes: return "max";
     }
     return "???";
 }
 ForkJoinOperation::ForkJoinOperation(JSContext *cx, HandleFunction fun, uint16_t sliceStart,
                                      uint16_t sliceEnd, ForkJoinMode mode)
   : bailouts(0),
     bailoutCause(ParallelBailoutNone),
     bailoutScript(cx),
     bailoutBytecode(nullptr),
     cx_(cx),
     fun_(fun),
     sliceStart_(sliceStart),
     sliceEnd_(sliceEnd),
     bailoutRecords_(cx),
     worklist_(cx),
     worklistData_(cx),
     mode_(mode)
 { }
 ExecutionStatus
 ForkJoinOperation::apply()
 {
     ExecutionStatus status;
     // High level outline of the procedure:
     //
     // - As we enter, we check for parallel script without "uncompiled" flag.
     // - If present, skip initial enqueue.
     // - While not too many bailouts:
     //   - While all scripts in worklist are not compiled:
     //     - For each script S in worklist:
     //       - Compile S if not compiled
     //         -> Error: fallback
     //       - If compiled, add call targets to worklist w/o checking uncompiled
     //         flag
     //     - If some compilations pending, run warmup iteration
     //     - Otherwise, clear "uncompiled targets" flag on main script and
     //       break from loop
     //   - Attempt parallel execution
     //     - If successful: return happily
     //     - If error: abort sadly
     //     - If bailout:
     //       - Invalidate any scripts that may need to be invalidated
     //       - Re-enqueue main script and any uncompiled scripts that were called
     // - Too many bailouts: Fallback to sequential
     JS_ASSERT_IF(!jit::IsBaselineEnabled(cx_), !jit::IsIonEnabled(cx_));
     if (!jit::IsBaselineEnabled(cx_) || !jit::IsIonEnabled(cx_))
         return sequentialExecution(true);
     SpewBeginOp(cx_, "ForkJoinOperation");
     // How many workers do we have, counting the main thread.
     unsigned numWorkers = cx_->runtime()->threadPool.numWorkers();
     if (!bailoutRecords_.resize(numWorkers))
         return SpewEndOp(ExecutionFatal);
     for (uint32_t i = 0; i < numWorkers; i++)
         bailoutRecords_[i].init(cx_);
     if (enqueueInitialScript(&status) == RedLight)
         return SpewEndOp(status);
     Spew(SpewOps, "Execution mode: %s", ForkJoinModeString(mode_));
     switch (mode_) {
       case ForkJoinModeNormal:
       case ForkJoinModeCompile:
       case ForkJoinModeBailout:
         break;
       case ForkJoinModeParallel:
       case ForkJoinModeRecover:
         // These two modes are used to check that every iteration can
         // be executed in parallel. They expect compilation to have
         // been done. But, when using gc zeal, it's possible that
         // compiled scripts were collected.
         if (ParallelTestsShouldPass(cx_) && worklist_.length() != 0) {
             JS_ReportError(cx_, "ForkJoin: compilation required in par or bailout mode");
             return SpewEndOp(ExecutionFatal);
         }
         break;
       case NumForkJoinModes:
         MOZ_ASSUME_UNREACHABLE("Invalid mode");
     }
     while (bailouts < MAX_BAILOUTS) {
         for (uint32_t i = 0; i < numWorkers; i++)
             bailoutRecords_[i].reset(cx_);
         if (compileForParallelExecution(&status) == RedLight)
             return SpewEndOp(status);
         JS_ASSERT(worklist_.length() == 0);
         if (parallelExecution(&status) == RedLight)
             return SpewEndOp(status);
         if (recoverFromBailout(&status) == RedLight)
             return SpewEndOp(status);
     }
     // After enough tries, just execute sequentially.
     return SpewEndOp(sequentialExecution(true));
 }
 ForkJoinOperation::TrafficLight
 ForkJoinOperation::enqueueInitialScript(ExecutionStatus *status)
 {
     // GreenLight: script successfully enqueued if necessary
     // RedLight: fatal error or fell back to sequential
     // The kernel should be a self-hosted function.
     if (!fun_->is<JSFunction>())
         return sequentialExecution(true, status);
     RootedFunction callee(cx_, &fun_->as<JSFunction>());
     if (!callee->isInterpreted() || !callee->isSelfHostedBuiltin())
         return sequentialExecution(true, status);
     // If the main script is already compiled, and we have no reason
     // to suspect any of its callees are not compiled, then we can
     // just skip the compilation step.
     RootedScript script(cx_, callee->getOrCreateScript(cx_));
     if (!script)
         return RedLight;
     if (script->hasParallelIonScript()) {
         // Notify that there's been activity on the entry script.
         JitCompartment *jitComp = cx_->compartment()->jitCompartment();
         if (!jitComp->notifyOfActiveParallelEntryScript(cx_, script)) {
             *status = ExecutionFatal;
             return RedLight;
         }
         if (!script->parallelIonScript()->hasUncompiledCallTarget()) {
             Spew(SpewOps, "Script %p:%s:%d already compiled, no uncompiled callees",
                  script.get(), script->filename(), script->lineno());
             return GreenLight;
         }
         Spew(SpewOps, "Script %p:%s:%d already compiled, may have uncompiled callees",
              script.get(), script->filename(), script->lineno());
     }
     // Otherwise, add to the worklist of scripts to process.
     if (addToWorklist(script) == RedLight)
         return fatalError(status);
     return GreenLight;
 }
 ForkJoinOperation::TrafficLight
 ForkJoinOperation::compileForParallelExecution(ExecutionStatus *status)
 {
     // GreenLight: all scripts compiled
     // RedLight: fatal error or completed work via warmups or fallback
     // This routine attempts to do whatever compilation is necessary
     // to execute a single parallel attempt. When it returns, either
     // (1) we have fallen back to sequential; (2) we have run enough
     // warmup runs to complete all the work; or (3) we have compiled
     // all scripts we think likely to be executed during a parallel
     // execution.
     RootedFunction fun(cx_);
     RootedScript script(cx_);
     // After 3 stalls, we stop waiting for a script to gather type
     // info and move on with execution.
     const uint32_t stallThreshold = 3;
     // This loop continues to iterate until the full contents of
     // `worklist` have been successfully compiled for parallel
     // execution. The compilations themselves typically occur on
     // helper threads. While we wait for the compilations to complete,
     // or for sufficient type information to be gathered, we execute
     // warmup iterations.
     while (true) {
         bool offMainThreadCompilationsInProgress = false;
         bool gatheringTypeInformation = false;
         // Walk over the worklist to check on the status of each entry.
         for (uint32_t i = 0; i < worklist_.length(); i++) {
             script = worklist_[i];
             script->ensureNonLazyCanonicalFunction(cx_);
             fun = script->functionNonDelazifying();
             // No baseline script means no type information, hence we
             // will not be able to compile very well.  In such cases,
             // we continue to run baseline iterations until either (1)
             // the potential callee *has* a baseline script or (2) the
             // potential callee's use count stops increasing,
             // indicating that they are not in fact a callee.
             if (!script->hasBaselineScript()) {
                 uint32_t previousUseCount = worklistData_[i].useCount;
                 uint32_t currentUseCount = script->getUseCount();
                 if (previousUseCount < currentUseCount) {
                     worklistData_[i].useCount = currentUseCount;
                     worklistData_[i].stallCount = 0;
                     gatheringTypeInformation = true;
                     Spew(SpewCompile,
                          "Script %p:%s:%d has no baseline script, "
                          "but use count grew from %d to %d",
                          script.get(), script->filename(), script->lineno(),
                          previousUseCount, currentUseCount);
                 } else {
                     uint32_t stallCount = ++worklistData_[i].stallCount;
                     if (stallCount < stallThreshold) {
                         gatheringTypeInformation = true;
                     }
                     Spew(SpewCompile,
                          "Script %p:%s:%d has no baseline script, "
                          "and use count has %u stalls at %d",
                          script.get(), script->filename(), script->lineno(),
                          stallCount, previousUseCount);
                 }
                 continue;
             }
             if (!script->hasParallelIonScript()) {
                 // Script has not yet been compiled. Attempt to compile it.
                 SpewBeginCompile(script);
                 MethodStatus mstatus = jit::CanEnterInParallel(cx_, script);
                 SpewEndCompile(mstatus);
                 switch (mstatus) {
                   case Method_Error:
                     return fatalError(status);
                   case Method_CantCompile:
                     Spew(SpewCompile,
                          "Script %p:%s:%d cannot be compiled, "
                          "falling back to sequential execution",
                          script.get(), script->filename(), script->lineno());
                     return sequentialExecution(true, status);
                   case Method_Skipped:
                     // A "skipped" result either means that we are compiling
                     // in parallel OR some other transient error occurred.
                     if (script->isParallelIonCompilingOffThread()) {
                         Spew(SpewCompile,
                              "Script %p:%s:%d compiling off-thread",
                              script.get(), script->filename(), script->lineno());
                         offMainThreadCompilationsInProgress = true;
                         continue;
                     }
                     return sequentialExecution(false, status);
                   case Method_Compiled:
                     Spew(SpewCompile,
                          "Script %p:%s:%d compiled",
                          script.get(), script->filename(), script->lineno());
                     JS_ASSERT(script->hasParallelIonScript());
                     if (isInitialScript(script)) {
                         JitCompartment *jitComp = cx_->compartment()->jitCompartment();
                         if (!jitComp->notifyOfActiveParallelEntryScript(cx_, script)) {
                             *status = ExecutionFatal;
                             return RedLight;
                         }
                     }
                     break;
                 }
             }
             // At this point, either the script was already compiled
             // or we just compiled it.  Check whether its "uncompiled
             // call target" flag is set and add the targets to our
             // worklist if so. Clear the flag after that, since we
             // will be compiling the call targets.
             JS_ASSERT(script->hasParallelIonScript());
             if (appendCallTargetsToWorklist(i, status) == RedLight)
                 return RedLight;
         }
         // If there is compilation occurring in a helper thread, then
         // run a warmup iterations in the main thread while we wait.
         // There is a chance that this warmup will finish all the work
         // we have to do, so we should stop then, unless we are in
         // compile mode, in which case we'll continue to block.
         //
         // Note that even in compile mode, we can't block *forever*:
         // - OMTC compiles will finish;
         // - no work is being done, so use counts on not-yet-baselined
         //   scripts will not increase.
         if (offMainThreadCompilationsInProgress || gatheringTypeInformation) {
             bool stopIfComplete = (mode_ != ForkJoinModeCompile);
             if (warmupExecution(stopIfComplete, status) == RedLight)
                 return RedLight;
             continue;
         }
         // All compilations are complete. However, be careful: it is
         // possible that a garbage collection occurred while we were
         // iterating and caused some of the scripts we thought we had
         // compiled to be collected. In that case, we will just have
         // to begin again.
         bool allScriptsPresent = true;
         for (uint32_t i = 0; i < worklist_.length(); i++) {
             if (!worklist_[i]->hasParallelIonScript()) {
                 if (worklistData_[i].stallCount < stallThreshold) {
                     worklistData_[i].reset();
                     allScriptsPresent = false;
                     Spew(SpewCompile,
                          "Script %p:%s:%d is not stalled, "
                          "but no parallel ion script found, "
                          "restarting loop",
                          script.get(), script->filename(), script->lineno());
                 }
             }
         }
         if (allScriptsPresent)
             break;
     }
     Spew(SpewCompile, "Compilation complete (final worklist length %d)",
          worklist_.length());
     // At this point, all scripts and their transitive callees are
     // either stalled (indicating they are unlikely to be called) or
     // in a compiled state.  Therefore we can clear the
     // "hasUncompiledCallTarget" flag on them and then clear the
     // worklist.
     for (uint32_t i = 0; i < worklist_.length(); i++) {
         if (worklist_[i]->hasParallelIonScript()) {
             JS_ASSERT(worklistData_[i].calleesEnqueued);
             worklist_[i]->parallelIonScript()->clearHasUncompiledCallTarget();
         } else {
             JS_ASSERT(worklistData_[i].stallCount >= stallThreshold);
         }
     }
     worklist_.clear();
     worklistData_.clear();
     return GreenLight;
 }
 ForkJoinOperation::TrafficLight
 ForkJoinOperation::appendCallTargetsToWorklist(uint32_t index, ExecutionStatus *status)
 {
     // GreenLight: call targets appended
     // RedLight: fatal error or completed work via warmups or fallback
     JS_ASSERT(worklist_[index]->hasParallelIonScript());
     // Check whether we have already enqueued the targets for
     // this entry and avoid doing it again if so.
     if (worklistData_[index].calleesEnqueued)
         return GreenLight;
     worklistData_[index].calleesEnqueued = true;
     // Iterate through the callees and enqueue them.
     RootedScript target(cx_);
     IonScript *ion = worklist_[index]->parallelIonScript();
     for (uint32_t i = 0; i < ion->callTargetEntries(); i++) {
         target = ion->callTargetList()[i];
         parallel::Spew(parallel::SpewCompile,
                        "Adding call target %s:%u",
                        target->filename(), target->lineno());
         if (appendCallTargetToWorklist(target, status) == RedLight)
             return RedLight;
     }
     return GreenLight;
 }
 ForkJoinOperation::TrafficLight
 ForkJoinOperation::appendCallTargetToWorklist(HandleScript script, ExecutionStatus *status)
 {
     // GreenLight: call target appended if necessary
     // RedLight: fatal error or completed work via warmups or fallback
     JS_ASSERT(script);
     // Fallback to sequential if disabled.
     if (!script->canParallelIonCompile()) {
         Spew(SpewCompile, "Skipping %p:%s:%u, canParallelIonCompile() is false",
              script.get(), script->filename(), script->lineno());
         return sequentialExecution(true, status);
     }
     if (script->hasParallelIonScript()) {
         // Skip if the code is expected to result in a bailout.
         if (script->parallelIonScript()->bailoutExpected()) {
             Spew(SpewCompile, "Skipping %p:%s:%u, bailout expected",
                  script.get(), script->filename(), script->lineno());
             return sequentialExecution(false, status);
         }
     }
     if (!addToWorklist(script))
         return fatalError(status);
     return GreenLight;
 }
 bool
 ForkJoinOperation::addToWorklist(HandleScript script)
 {
     for (uint32_t i = 0; i < worklist_.length(); i++) {
         if (worklist_[i] == script) {
             Spew(SpewCompile, "Skipping %p:%s:%u, already in worklist",
                  script.get(), script->filename(), script->lineno());
             return true;
         }
     }
     Spew(SpewCompile, "Enqueued %p:%s:%u",
          script.get(), script->filename(), script->lineno());
     // Note that we add all possibly compilable functions to the worklist,
     // even if they're already compiled. This is so that we can return
     // Method_Compiled and not Method_Skipped if we have a worklist full of
     // already-compiled functions.
     if (!worklist_.append(script))
         return false;
     // we have not yet enqueued the callees of this script
     if (!worklistData_.append(WorklistData()))
         return false;
     worklistData_[worklistData_.length() - 1].reset();
     return true;
 }
 ForkJoinOperation::TrafficLight
 ForkJoinOperation::sequentialExecution(bool disqualified, ExecutionStatus *status)
 {
     // RedLight: fatal error or completed work
     *status = sequentialExecution(disqualified);
     return RedLight;
 }
 ExecutionStatus
 ForkJoinOperation::sequentialExecution(bool disqualified)
 {
     // XXX use disqualified to set parallelIon to ION_DISABLED_SCRIPT?
     Spew(SpewOps, "Executing sequential execution (disqualified=%d).",
          disqualified);
     if (sliceStart_ == sliceEnd_)
         return ExecutionSequential;
     RootedValue funVal(cx_, ObjectValue(*fun_));
     if (!ExecuteSequentially(cx_, funVal, &sliceStart_, sliceEnd_))
         return ExecutionFatal;
     MOZ_ASSERT(sliceStart_ == sliceEnd_);
     return ExecutionSequential;
 }
 ForkJoinOperation::TrafficLight
 ForkJoinOperation::fatalError(ExecutionStatus *status)
 {
     // RedLight: fatal error
     *status = ExecutionFatal;
     return RedLight;
 }
 static const char *
 BailoutExplanation(ParallelBailoutCause cause)
 {
     switch (cause) {
       case ParallelBailoutNone:
         return "no particular reason";
       case ParallelBailoutCompilationSkipped:
         return "compilation failed (method skipped)";
       case ParallelBailoutCompilationFailure:
         return "compilation failed";
       case ParallelBailoutInterrupt:
         return "interrupted";
       case ParallelBailoutFailedIC:
         return "failed to attach stub to IC";
       case ParallelBailoutHeapBusy:
         return "heap busy flag set during interrupt";
       case ParallelBailoutMainScriptNotPresent:
         return "main script not present";
       case ParallelBailoutCalledToUncompiledScript:
         return "called to uncompiled script";
       case ParallelBailoutIllegalWrite:
         return "illegal write";
       case ParallelBailoutAccessToIntrinsic:
         return "access to intrinsic";
       case ParallelBailoutOverRecursed:
         return "over recursed";
       case ParallelBailoutOutOfMemory:
         return "out of memory";
       case ParallelBailoutUnsupported:
         return "unsupported";
       case ParallelBailoutUnsupportedVM:
         return "unsupported operation in VM call";
       case ParallelBailoutUnsupportedStringComparison:
         return "unsupported string comparison";
       case ParallelBailoutRequestedGC:
         return "requested GC";
       case ParallelBailoutRequestedZoneGC:
         return "requested zone GC";
       default:
         return "no known reason";
     }
 }
 bool
 ForkJoinOperation::isInitialScript(HandleScript script)
 {
     return fun_->is<JSFunction>() && (fun_->as<JSFunction>().nonLazyScript() == script);
 }
 void
 ForkJoinOperation::determineBailoutCause()
 {
     bailoutCause = ParallelBailoutNone;
     for (uint32_t i = 0; i < bailoutRecords_.length(); i++) {
         if (bailoutRecords_[i].cause == ParallelBailoutNone)
             continue;
         if (bailoutRecords_[i].cause == ParallelBailoutInterrupt)
             continue;
         bailoutCause = bailoutRecords_[i].cause;
         const char *causeStr = BailoutExplanation(bailoutCause);
         if (bailoutRecords_[i].depth) {
             bailoutScript = bailoutRecords_[i].trace[0].script;
             bailoutBytecode = bailoutRecords_[i].trace[0].bytecode;
             const char *filename = bailoutScript->filename();
             int line = JS_PCToLineNumber(cx_, bailoutScript, bailoutBytecode);
             JS_ReportWarning(cx_, "Bailed out of parallel operation: %s at %s:%d",
                              causeStr, filename, line);
             Spew(SpewBailouts, "Bailout from thread %d: cause %d at loc %s:%d",
                  i,
                  bailoutCause,
                  bailoutScript->filename(),
                  PCToLineNumber(bailoutScript, bailoutBytecode));
         } else {
             JS_ReportWarning(cx_, "Bailed out of parallel operation: %s",
                              causeStr);
             Spew(SpewBailouts, "Bailout from thread %d: cause %d, unknown loc",
                  i,
                  bailoutCause);
         }
     }
 }
 bool
 ForkJoinOperation::invalidateBailedOutScripts()
 {
     Vector<types::RecompileInfo> invalid(cx_);
     for (uint32_t i = 0; i < bailoutRecords_.length(); i++) {
         RootedScript script(cx_, bailoutRecords_[i].topScript);
         // No script to invalidate.
         if (!script || !script->hasParallelIonScript())
             continue;
         Spew(SpewBailouts,
              "Bailout from thread %d: cause %d, topScript %p:%s:%d",
              i,
              bailoutRecords_[i].cause,
              script.get(), script->filename(), script->lineno());
         switch (bailoutRecords_[i].cause) {
           // An interrupt is not the fault of the script, so don't
           // invalidate it.
           case ParallelBailoutInterrupt: continue;
           // An illegal write will not be made legal by invalidation.
           case ParallelBailoutIllegalWrite: continue;
           // For other cases, consider invalidation.
           default: break;
         }
         // Already invalidated.
         if (hasScript(invalid, script))
             continue;
         Spew(SpewBailouts, "Invalidating script %p:%s:%d due to cause %d",
              script.get(), script->filename(), script->lineno(),
              bailoutRecords_[i].cause);
         types::RecompileInfo co = script->parallelIonScript()->recompileInfo();
         if (!invalid.append(co))
             return false;
         // any script that we have marked for invalidation will need
         // to be recompiled
         if (!addToWorklist(script))
             return false;
     }
     Invalidate(cx_, invalid);
     return true;
 }
 ForkJoinOperation::TrafficLight
 ForkJoinOperation::warmupExecution(bool stopIfComplete, ExecutionStatus *status)
 {
     // GreenLight: warmup succeeded, still more work to do
     // RedLight: fatal error or warmup completed all work (check status)
     if (sliceStart_ == sliceEnd_) {
         Spew(SpewOps, "Warmup execution finished all the work.");
         if (stopIfComplete) {
             *status = ExecutionWarmup;
             return RedLight;
         }
         // If we finished all slices in warmup, be sure check the
         // interrupt flag. This is because we won't be running more JS
         // code, and thus no more automatic checking of the interrupt
         // flag.
         if (!CheckForInterrupt(cx_)) {
             *status = ExecutionFatal;
             return RedLight;
         }
         return GreenLight;
     }
     Spew(SpewOps, "Executing warmup from slice %d.", sliceStart_);
     AutoEnterWarmup warmup(cx_->runtime());
     RootedValue funVal(cx_, ObjectValue(*fun_));
     if (!ExecuteSequentially(cx_, funVal, &sliceStart_, sliceStart_ + 1)) {
         *status = ExecutionFatal;
         return RedLight;
     }
     return GreenLight;
 }
 ForkJoinOperation::TrafficLight
 ForkJoinOperation::parallelExecution(ExecutionStatus *status)
 {
     // GreenLight: bailout occurred, keep trying
     // RedLight: fatal error or all work completed
     // Recursive use of the ThreadPool is not supported.  Right now we
     // cannot get here because parallel code cannot invoke native
     // functions such as ForkJoin().
     JS_ASSERT(ForkJoinContext::current() == nullptr);
     if (sliceStart_ == sliceEnd_) {
         Spew(SpewOps, "Warmup execution finished all the work.");
         *status = ExecutionWarmup;
         return RedLight;
     }
     ForkJoinActivation activation(cx_);
     ThreadPool *threadPool = &cx_->runtime()->threadPool;
     ForkJoinShared shared(cx_, threadPool, fun_, sliceStart_, sliceEnd_, &bailoutRecords_[0]);
     if (!shared.init()) {
         *status = ExecutionFatal;
         return RedLight;
     }
     switch (shared.execute()) {
       case TP_SUCCESS:
         *status = ExecutionParallel;
         return RedLight;
       case TP_FATAL:
         *status = ExecutionFatal;
         return RedLight;
       case TP_RETRY_SEQUENTIALLY:
       case TP_RETRY_AFTER_GC:
         break; // bailout
     }
     return GreenLight;
 }
 ForkJoinOperation::TrafficLight
 ForkJoinOperation::recoverFromBailout(ExecutionStatus *status)
 {
     // GreenLight: bailout recovered, try to compile-and-run again
     // RedLight: fatal error
     bailouts += 1;
     determineBailoutCause();
     SpewBailout(bailouts, bailoutScript, bailoutBytecode, bailoutCause);
     // After any bailout, we always scan over callee list of main
     // function, if nothing else
     RootedScript mainScript(cx_, fun_->nonLazyScript());
     if (!addToWorklist(mainScript))
         return fatalError(status);
     // Also invalidate and recompile any callees that were implicated
     // by the bailout
     if (!invalidateBailedOutScripts())
         return fatalError(status);
     if (warmupExecution(/*stopIfComplete:*/true, status) == RedLight)
         return RedLight;
     return GreenLight;
 }
 bool
 ForkJoinOperation::hasScript(Vector<types::RecompileInfo> &scripts, JSScript *script)
 {
     for (uint32_t i = 0; i < scripts.length(); i++) {
         if (scripts[i] == script->parallelIonScript()->recompileInfo())
             return true;
     }
     return false;
 }
 // Can only enter callees with a valid IonScript.
 template <uint32_t maxArgc>
 class ParallelIonInvoke
 {
     EnterJitCode enter_;
     void *jitcode_;
     void *calleeToken_;
     Value argv_[maxArgc + 2];
     uint32_t argc_;
   public:
     Value *args;
     ParallelIonInvoke(JSRuntime *rt,
                       HandleFunction callee,
                       uint32_t argc)
       : argc_(argc),
         args(argv_ + 2)
     {
         JS_ASSERT(argc <= maxArgc + 2);
         // Set 'callee' and 'this'.
         argv_[0] = ObjectValue(*callee);
         argv_[1] = UndefinedValue();
         // Find JIT code pointer.
         IonScript *ion = callee->nonLazyScript()->parallelIonScript();
         JitCode *code = ion->method();
         jitcode_ = code->raw();
         enter_ = rt->jitRuntime()->enterIon();
         calleeToken_ = CalleeToToken(callee);
     }
     bool invoke(PerThreadData *perThread) {
         RootedValue result(perThread);
         CALL_GENERATED_CODE(enter_, jitcode_, argc_ + 1, argv_ + 1, nullptr, calleeToken_,
                             nullptr, 0, result.address());
         return !result.isMagic();
     }
 };
 /////////////////////////////////////////////////////////////////////////////
 // ForkJoinShared
 //
 ForkJoinShared::ForkJoinShared(JSContext *cx,
                                ThreadPool *threadPool,
                                HandleFunction fun,
                                uint16_t sliceStart,
                                uint16_t sliceEnd,
                                ParallelBailoutRecord *records)
   : cx_(cx),
     threadPool_(threadPool),
     fun_(fun),
     sliceStart_(sliceStart),
     sliceEnd_(sliceEnd),
     cxLock_(nullptr),
     records_(records),
     allocators_(cx),
     gcRequested_(false),
     gcReason_(JS::gcreason::NUM_REASONS),
     gcZone_(nullptr),
     abort_(false),
     fatal_(false)
 {
 }
 bool
 ForkJoinShared::init()
 {
     // Create temporary arenas to hold the data allocated during the
     // parallel code.
     //
     // Note: you might think (as I did, initially) that we could use
     // compartment |Allocator| for the main thread.  This is not true,
     // because when executing parallel code we sometimes check what
     // arena list an object is in to decide if it is writable.  If we
     // used the compartment |Allocator| for the main thread, then the
     // main thread would be permitted to write to any object it wants.
     if (!Monitor::init())
         return false;
     cxLock_ = PR_NewLock();
     if (!cxLock_)
         return false;
     for (unsigned i = 0; i < threadPool_->numWorkers(); i++) {
         Allocator *allocator = cx_->new_<Allocator>(cx_->zone());
         if (!allocator)
             return false;
         if (!allocators_.append(allocator)) {
             js_delete(allocator);
             return false;
         }
     }
     return true;
 }
 ForkJoinShared::~ForkJoinShared()
 {
     PR_DestroyLock(cxLock_);
     while (allocators_.length() > 0)
         js_delete(allocators_.popCopy());
 }
 ParallelResult
 ForkJoinShared::execute()
 {
     // Sometimes a GC request occurs *just before* we enter into the
     // parallel section.  Rather than enter into the parallel section
     // and then abort, we just check here and abort early.
     if (cx_->runtime()->interruptPar)
         return TP_RETRY_SEQUENTIALLY;
     AutoLockMonitor lock(*this);
     ParallelResult jobResult = TP_SUCCESS;
     {
         AutoUnlockMonitor unlock(*this);
         // Push parallel tasks and wait until they're all done.
         jobResult = threadPool_->executeJob(cx_, this, sliceStart_, sliceEnd_);
         if (jobResult == TP_FATAL)
             return TP_FATAL;
     }
     transferArenasToCompartmentAndProcessGCRequests();
     // Check if any of the workers failed.
     if (abort_) {
         if (fatal_)
             return TP_FATAL;
         return TP_RETRY_SEQUENTIALLY;
     }
 #ifdef DEBUG
     Spew(SpewOps, "Completed parallel job [slices: %d, threads: %d, stolen: %d (work stealing:%s)]",
          sliceEnd_ - sliceStart_,
          threadPool_->numWorkers(),
          threadPool_->stolenSlices(),
          threadPool_->workStealing() ? "ON" : "OFF");
 #endif
     // Everything went swimmingly. Give yourself a pat on the back.
     return jobResult;
 }
 void
 ForkJoinShared::transferArenasToCompartmentAndProcessGCRequests()
 {
     JSCompartment *comp = cx_->compartment();
     for (unsigned i = 0; i < threadPool_->numWorkers(); i++)
         comp->adoptWorkerAllocator(allocators_[i]);
     if (gcRequested_) {
         if (!gcZone_)
             TriggerGC(cx_->runtime(), gcReason_);
         else
             TriggerZoneGC(gcZone_, gcReason_);
         gcRequested_ = false;
         gcZone_ = nullptr;
     }
 }
 bool
 ForkJoinShared::executeFromWorker(ThreadPoolWorker *worker, uintptr_t stackLimit)
 {
     PerThreadData thisThread(cx_->runtime());
     if (!thisThread.init()) {
         setAbortFlagAndRequestInterrupt(true);
         return false;
     }
     TlsPerThreadData.set(&thisThread);
 #ifdef JS_ARM_SIMULATOR
     stackLimit = Simulator::StackLimit();
 #endif
     // Don't use setIonStackLimit() because that acquires the ionStackLimitLock, and the
     // lock has not been initialized in these cases.
     thisThread.jitStackLimit = stackLimit;
     executePortion(&thisThread, worker);
     TlsPerThreadData.set(nullptr);
     return !abort_;
 }
 bool
 ForkJoinShared::executeFromMainThread(ThreadPoolWorker *worker)
 {
     executePortion(&cx_->mainThread(), worker);
     return !abort_;
 }
 void
 ForkJoinShared::executePortion(PerThreadData *perThread, ThreadPoolWorker *worker)
 {
     // WARNING: This code runs ON THE PARALLEL WORKER THREAD.
     // Be careful when accessing cx_.
     // ForkJoinContext already contains an AutoAssertNoGC; however, the analysis
     // does not propagate this type information. We duplicate the assertion
     // here for maximum clarity.
     JS::AutoAssertNoGC nogc(runtime());
     Allocator *allocator = allocators_[worker->id()];
     ForkJoinContext cx(perThread, worker, allocator, this, &records_[worker->id()]);
     AutoSetForkJoinContext autoContext(&cx);
 #ifdef DEBUG
     // Set the maximum worker and slice number for prettier spewing.
     cx.maxWorkerId = threadPool_->numWorkers();
 #endif
     Spew(SpewOps, "Up");
     // Make a new IonContext for the slice, which is needed if we need to
     // re-enter the VM.
     IonContext icx(CompileRuntime::get(cx_->runtime()),
                    CompileCompartment::get(cx_->compartment()),
                    nullptr);
     JS_ASSERT(cx.bailoutRecord->topScript == nullptr);
     if (!fun_->nonLazyScript()->hasParallelIonScript()) {
         // Sometimes, particularly with GCZeal, the parallel ion
         // script can be collected between starting the parallel
         // op and reaching this point.  In that case, we just fail
         // and fallback.
         Spew(SpewOps, "Down (Script no longer present)");
         cx.bailoutRecord->setCause(ParallelBailoutMainScriptNotPresent);
         setAbortFlagAndRequestInterrupt(false);
     } else {
         ParallelIonInvoke<3> fii(cx_->runtime(), fun_, 3);
         fii.args[0] = Int32Value(worker->id());
         fii.args[1] = Int32Value(sliceStart_);
         fii.args[2] = Int32Value(sliceEnd_);
         bool ok = fii.invoke(perThread);
         JS_ASSERT(ok == !cx.bailoutRecord->topScript);
         if (!ok)
             setAbortFlagAndRequestInterrupt(false);
     }
     Spew(SpewOps, "Down");
 }
 void
 ForkJoinShared::setAbortFlagDueToInterrupt(ForkJoinContext &cx)
 {
     JS_ASSERT(cx_->runtime()->interruptPar);
     // The GC Needed flag should not be set during parallel
     // execution.  Instead, one of the requestGC() or
     // requestZoneGC() methods should be invoked.
     JS_ASSERT(!cx_->runtime()->gcIsNeeded);
     if (!abort_) {
         cx.bailoutRecord->setCause(ParallelBailoutInterrupt);
         setAbortFlagAndRequestInterrupt(false);
     }
 }
 void
 ForkJoinShared::setAbortFlagAndRequestInterrupt(bool fatal)
 {
     AutoLockMonitor lock(*this);
     abort_ = true;
     fatal_ = fatal_ || fatal;
     // Note: The ForkJoin trigger here avoids the expensive memory protection needed to
     // interrupt Ion code compiled for sequential execution.
     cx_->runtime()->requestInterrupt(JSRuntime::RequestInterruptAnyThreadForkJoin);
 }
 void
 ForkJoinShared::requestGC(JS::gcreason::Reason reason)
 {
     AutoLockMonitor lock(*this);
     gcZone_ = nullptr;
     gcReason_ = reason;
     gcRequested_ = true;
 }
 void
 ForkJoinShared::requestZoneGC(JS::Zone *zone, JS::gcreason::Reason reason)
 {
     AutoLockMonitor lock(*this);
     if (gcRequested_ && gcZone_ != zone) {
         // If a full GC has been requested, or a GC for another zone,
         // issue a request for a full GC.
         gcZone_ = nullptr;
         gcReason_ = reason;
         gcRequested_ = true;
     } else {
         // Otherwise, just GC this zone.
         gcZone_ = zone;
         gcReason_ = reason;
         gcRequested_ = true;
     }
 }
 /////////////////////////////////////////////////////////////////////////////
 // ForkJoinContext
 //
 ForkJoinContext::ForkJoinContext(PerThreadData *perThreadData, ThreadPoolWorker *worker,
                                  Allocator *allocator, ForkJoinShared *shared,
                                  ParallelBailoutRecord *bailoutRecord)
   : ThreadSafeContext(shared->runtime(), perThreadData, Context_ForkJoin),
     bailoutRecord(bailoutRecord),
     targetRegionStart(nullptr),
     targetRegionEnd(nullptr),
     shared_(shared),
     worker_(worker),
     acquiredJSContext_(false),
     nogc_(shared->runtime())
 {
     /*
      * Unsafely set the zone. This is used to track malloc counters and to
      * trigger GCs and is otherwise not thread-safe to access.
      */
     zone_ = shared->zone();
     /*
      * Unsafely set the compartment. This is used to get read-only access to
      * shared tables.
      */
     compartment_ = shared->compartment();
     allocator_ = allocator;
 }
 bool
 ForkJoinContext::isMainThread() const
 {
     return perThreadData == &shared_->runtime()->mainThread;
 }
 JSRuntime *
 ForkJoinContext::runtime()
 {
     return shared_->runtime();
 }
 JSContext *
 ForkJoinContext::acquireJSContext()
 {
     JSContext *cx = shared_->acquireJSContext();
     JS_ASSERT(!acquiredJSContext_);
     acquiredJSContext_ = true;
     return cx;
 }
 void
 ForkJoinContext::releaseJSContext()
 {
     JS_ASSERT(acquiredJSContext_);
     acquiredJSContext_ = false;
     return shared_->releaseJSContext();
 }
 bool
 ForkJoinContext::hasAcquiredJSContext() const
 {
     return acquiredJSContext_;
 }
 bool
 ForkJoinContext::check()
 {
     if (runtime()->interruptPar) {
         shared_->setAbortFlagDueToInterrupt(*this);
         return false;
     }
     return true;
 }
 void
 ForkJoinContext::requestGC(JS::gcreason::Reason reason)
 {
     shared_->requestGC(reason);
     bailoutRecord->setCause(ParallelBailoutRequestedGC);
     shared_->setAbortFlagAndRequestInterrupt(false);
 }
 void
 ForkJoinContext::requestZoneGC(JS::Zone *zone, JS::gcreason::Reason reason)
 {
     shared_->requestZoneGC(zone, reason);
     bailoutRecord->setCause(ParallelBailoutRequestedZoneGC);
     shared_->setAbortFlagAndRequestInterrupt(false);
 }
 bool
 ForkJoinContext::setPendingAbortFatal(ParallelBailoutCause cause)
 {
     shared_->setPendingAbortFatal();
     bailoutRecord->setCause(cause);
     return false;
 }
 //////////////////////////////////////////////////////////////////////////////
 // ParallelBailoutRecord
 void
 js::ParallelBailoutRecord::init(JSContext *cx)
 {
     reset(cx);
 }
 void
 js::ParallelBailoutRecord::reset(JSContext *cx)
 {
     topScript = nullptr;
     cause = ParallelBailoutNone;
     depth = 0;
 }
 void
 js::ParallelBailoutRecord::setCause(ParallelBailoutCause cause,
                                     JSScript *outermostScript,
                                     JSScript *currentScript,
                                     jsbytecode *currentPc)
 {
     this->cause = cause;
     updateCause(cause, outermostScript, currentScript, currentPc);
 }
 void
 js::ParallelBailoutRecord::updateCause(ParallelBailoutCause cause,
                                        JSScript *outermostScript,
                                        JSScript *currentScript,
                                        jsbytecode *currentPc)
 {
     JS_ASSERT_IF(outermostScript, currentScript);
     JS_ASSERT_IF(outermostScript, outermostScript->hasParallelIonScript());
     JS_ASSERT_IF(currentScript, outermostScript);
     JS_ASSERT_IF(!currentScript, !currentPc);
     if (this->cause == ParallelBailoutNone)
         this->cause = cause;
     if (outermostScript)
         this->topScript = outermostScript;
     if (currentScript)
         addTrace(currentScript, currentPc);
 }
 void
 js::ParallelBailoutRecord::addTrace(JSScript *script,
                                     jsbytecode *pc)
 {
     // Ideally, this should never occur, because we should always have
     // a script when we invoke setCause, but I havent' fully
     // refactored things to that point yet:
     if (topScript == nullptr && script != nullptr)
         topScript = script;
     if (depth < MaxDepth) {
         trace[depth].script = script;
         trace[depth].bytecode = pc;
         depth += 1;
     }
 }
 //////////////////////////////////////////////////////////////////////////////
 //
 // Debug spew
 //
 #ifdef DEBUG
 static const char *
 ExecutionStatusToString(ExecutionStatus status)
 {
     switch (status) {
       case ExecutionFatal:
         return "fatal";
       case ExecutionSequential:
         return "sequential";
       case ExecutionWarmup:
         return "warmup";
       case ExecutionParallel:
         return "parallel";
     }
     return "(unknown status)";
 }
 static const char *
 MethodStatusToString(MethodStatus status)
 {
     switch (status) {
       case Method_Error:
         return "error";
       case Method_CantCompile:
         return "can't compile";
       case Method_Skipped:
         return "skipped";
       case Method_Compiled:
         return "compiled";
     }
     return "(unknown status)";
 }
 static unsigned
 NumberOfDigits(unsigned n)
 {
     if (n == 0)
         return 1;
     unsigned d = 0;
     while (n != 0) {
         d++;
         n /= 10;
     }
     return d;
 }
 static const size_t BufferSize = 4096;
 class ParallelSpewer
 {
     uint32_t depth;
     bool colorable;
     bool active[NumSpewChannels];
     const char *color(const char *colorCode) {
         if (!colorable)
             return "";
         return colorCode;
     }
     const char *reset() { return color("\x1b[0m"); }
     const char *bold() { return color("\x1b[1m"); }
     const char *red() { return color("\x1b[31m"); }
     const char *green() { return color("\x1b[32m"); }
     const char *yellow() { return color("\x1b[33m"); }
     const char *cyan() { return color("\x1b[36m"); }
     const char *workerColor(uint32_t id) {
         static const char *colors[] = {
             "\x1b[7m\x1b[31m", "\x1b[7m\x1b[32m", "\x1b[7m\x1b[33m",
             "\x1b[7m\x1b[34m", "\x1b[7m\x1b[35m", "\x1b[7m\x1b[36m",
             "\x1b[7m\x1b[37m",
             "\x1b[31m", "\x1b[32m", "\x1b[33m",
             "\x1b[34m", "\x1b[35m", "\x1b[36m",
             "\x1b[37m"
         };
         return color(colors[id % 14]);
     }
   public:
     ParallelSpewer()
       : depth(0)
     {
         const char *env;
         mozilla::PodArrayZero(active);
         env = getenv("PAFLAGS");
         if (env) {
             if (strstr(env, "ops"))
                 active[SpewOps] = true;
             if (strstr(env, "compile"))
                 active[SpewCompile] = true;
             if (strstr(env, "bailouts"))
                 active[SpewBailouts] = true;
             if (strstr(env, "full")) {
                 for (uint32_t i = 0; i < NumSpewChannels; i++)
                     active[i] = true;
             }
         }
         env = getenv("TERM");
         if (env && isatty(fileno(stderr))) {
             if (strcmp(env, "xterm-color") == 0 || strcmp(env, "xterm-256color") == 0)
                 colorable = true;
         }
     }
     bool isActive(js::parallel::SpewChannel channel) {
         return active[channel];
     }
     void spewVA(js::parallel::SpewChannel channel, const char *fmt, va_list ap) {
         if (!active[channel])
             return;
         // Print into a buffer first so we use one fprintf, which usually
         // doesn't get interrupted when running with multiple threads.
         char buf[BufferSize];
         if (ForkJoinContext *cx = ForkJoinContext::current()) {
             // Print the format first into a buffer to right-justify the
             // worker ids.
             char bufbuf[BufferSize];
             JS_snprintf(bufbuf, BufferSize, "[%%sParallel:%%0%du%%s] ",
                         NumberOfDigits(cx->maxWorkerId));
             JS_snprintf(buf, BufferSize, bufbuf, workerColor(cx->workerId()),
                         cx->workerId(), reset());
         } else {
             JS_snprintf(buf, BufferSize, "[Parallel:M] ");
         }
         for (uint32_t i = 0; i < depth; i++)
             JS_snprintf(buf + strlen(buf), BufferSize, "  ");
         JS_vsnprintf(buf + strlen(buf), BufferSize, fmt, ap);
         JS_snprintf(buf + strlen(buf), BufferSize, "\n");
         fprintf(stderr, "%s", buf);
     }
     void spew(js::parallel::SpewChannel channel, const char *fmt, ...) {
         va_list ap;
         va_start(ap, fmt);
         spewVA(channel, fmt, ap);
         va_end(ap);
     }
     void beginOp(JSContext *cx, const char *name) {
         if (!active[SpewOps])
             return;
         if (cx) {
             jsbytecode *pc;
             RootedScript script(cx, cx->currentScript(&pc));
             if (script && pc) {
                 NonBuiltinScriptFrameIter iter(cx);
                 if (iter.done()) {
                     spew(SpewOps, "%sBEGIN %s%s (%s:%u)", bold(), name, reset(),
                          script->filename(), PCToLineNumber(script, pc));
                 } else {
                     spew(SpewOps, "%sBEGIN %s%s (%s:%u -> %s:%u)", bold(), name, reset(),
                          iter.script()->filename(), PCToLineNumber(iter.script(), iter.pc()),
                          script->filename(), PCToLineNumber(script, pc));
                 }
             } else {
                 spew(SpewOps, "%sBEGIN %s%s", bold(), name, reset());
             }
         } else {
             spew(SpewOps, "%sBEGIN %s%s", bold(), name, reset());
         }
         depth++;
     }
     void endOp(ExecutionStatus status) {
         if (!active[SpewOps])
             return;
         JS_ASSERT(depth > 0);
         depth--;
         const char *statusColor;
         switch (status) {
           case ExecutionFatal:
             statusColor = red();
             break;
           case ExecutionSequential:
             statusColor = yellow();
             break;
           case ExecutionParallel:
             statusColor = green();
             break;
           default:
             statusColor = reset();
             break;
         }
         spew(SpewOps, "%sEND %s%s%s", bold(),
              statusColor, ExecutionStatusToString(status), reset());
     }
     void bailout(uint32_t count, HandleScript script,
                  jsbytecode *pc, ParallelBailoutCause cause) {
         if (!active[SpewOps])
             return;
         const char *filename = "";
         unsigned line=0, column=0;
         if (script) {
             line = PCToLineNumber(script, pc, &column);
             filename = script->filename();
         }
         spew(SpewOps, "%s%sBAILOUT %d%s: %s (%d) at %s:%d:%d", bold(), yellow(), count, reset(),
              BailoutExplanation(cause), cause, filename, line, column);
     }
     void beginCompile(HandleScript script) {
         if (!active[SpewCompile])
             return;
         spew(SpewCompile, "COMPILE %p:%s:%u", script.get(), script->filename(), script->lineno());
         depth++;
     }
     void endCompile(MethodStatus status) {
         if (!active[SpewCompile])
             return;
         JS_ASSERT(depth > 0);
         depth--;
         const char *statusColor;
         switch (status) {
           case Method_Error:
           case Method_CantCompile:
             statusColor = red();
             break;
           case Method_Skipped:
             statusColor = yellow();
             break;
           case Method_Compiled:
             statusColor = green();
             break;
           default:
             statusColor = reset();
             break;
         }
         spew(SpewCompile, "END %s%s%s", statusColor, MethodStatusToString(status), reset());
     }
     void spewMIR(MDefinition *mir, const char *fmt, va_list ap) {
         if (!active[SpewCompile])
             return;
         char buf[BufferSize];
         JS_vsnprintf(buf, BufferSize, fmt, ap);
         JSScript *script = mir->block()->info().script();
         spew(SpewCompile, "%s%s%s: %s (%s:%u)", cyan(), mir->opName(), reset(), buf,
              script->filename(), PCToLineNumber(script, mir->trackedPc()));
     }
     void spewBailoutIR(IonLIRTraceData *data) {
         if (!active[SpewBailouts])
             return;
         // If we didn't bail from a LIR/MIR but from a propagated parallel
         // bailout, don't bother printing anything since we've printed it
         // elsewhere.
         if (data->mirOpName && data->script) {
             spew(SpewBailouts, "%sBailout%s: %s / %s%s%s (block %d lir %d) (%s:%u)", yellow(), reset(),
                  data->lirOpName, cyan(), data->mirOpName, reset(),
                  data->blockIndex, data->lirIndex, data->script->filename(),
                  PCToLineNumber(data->script, data->pc));
         }
     }
 };
 // Singleton instance of the spewer.
 static ParallelSpewer spewer;
 bool
 parallel::SpewEnabled(SpewChannel channel)
 {
     return spewer.isActive(channel);
 }
 void
 parallel::Spew(SpewChannel channel, const char *fmt, ...)
 {
     va_list ap;
     va_start(ap, fmt);
     spewer.spewVA(channel, fmt, ap);
     va_end(ap);
 }
 void
 parallel::SpewBeginOp(JSContext *cx, const char *name)
 {
     spewer.beginOp(cx, name);
 }
 ExecutionStatus
 parallel::SpewEndOp(ExecutionStatus status)
 {
     spewer.endOp(status);
     return status;
 }
 void
 parallel::SpewBailout(uint32_t count, HandleScript script,
                       jsbytecode *pc, ParallelBailoutCause cause)
 {
     spewer.bailout(count, script, pc, cause);
 }
 void
 parallel::SpewBeginCompile(HandleScript script)
 {
     spewer.beginCompile(script);
 }
 MethodStatus
 parallel::SpewEndCompile(MethodStatus status)
 {
     spewer.endCompile(status);
     return status;
 }
 void
 parallel::SpewMIR(MDefinition *mir, const char *fmt, ...)
 {
     va_list ap;
     va_start(ap, fmt);
     spewer.spewMIR(mir, fmt, ap);
     va_end(ap);
 }
 void
 parallel::SpewBailoutIR(IonLIRTraceData *data)
 {
     spewer.spewBailoutIR(data);
 }
 #endif // DEBUG
 bool
 js::InExclusiveParallelSection()
 {
     return InParallelSection() && ForkJoinContext::current()->hasAcquiredJSContext();
 }
 bool
 js::ParallelTestsShouldPass(JSContext *cx)
 {
     return jit::IsIonEnabled(cx) &&
            jit::IsBaselineEnabled(cx) &&
            !jit::js_JitOptions.eagerCompilation &&
            jit::js_JitOptions.baselineUsesBeforeCompile != 0 &&
            cx->runtime()->gcZeal() == 0;
 }
 void
 js::RequestInterruptForForkJoin(JSRuntime *rt, JSRuntime::InterruptMode mode)
 {
     if (mode != JSRuntime::RequestInterruptAnyThreadDontStopIon)
         rt->interruptPar = true;
 }
 bool
 js::intrinsic_SetForkJoinTargetRegion(JSContext *cx, unsigned argc, Value *vp)
 {
     // This version of SetForkJoinTargetRegion is called during
     // sequential execution. It is a no-op. The parallel version
     // is intrinsic_SetForkJoinTargetRegionPar(), below.
     return true;
 }
 static bool
 intrinsic_SetForkJoinTargetRegionPar(ForkJoinContext *cx, unsigned argc, Value *vp)
 {
     // Sets the *target region*, which is the portion of the output
     // buffer that the current iteration is permitted to write to.
     //
     // Note: it is important that the target region should be an
     // entire element (or several elements) of the output array and
     // not some region that spans from the middle of one element into
     // the middle of another. This is because the guarding code
     // assumes that handles, which never straddle across elements,
     // will either be contained entirely within the target region or
     // be contained entirely without of the region, and not straddling
     // the region nor encompassing it.
     CallArgs args = CallArgsFromVp(argc, vp);
     JS_ASSERT(argc == 3);
     JS_ASSERT(args[0].isObject() && args[0].toObject().is<TypedObject>());
     JS_ASSERT(args[1].isInt32());
     JS_ASSERT(args[2].isInt32());
     uint8_t *mem = args[0].toObject().as<TypedObject>().typedMem();
     int32_t start = args[1].toInt32();
     int32_t end = args[2].toInt32();
     cx->targetRegionStart = mem + start;
     cx->targetRegionEnd = mem + end;
     return true;
 }
 JS_JITINFO_NATIVE_PARALLEL(js::intrinsic_SetForkJoinTargetRegionInfo,
                            intrinsic_SetForkJoinTargetRegionPar);
 bool
 js::intrinsic_ClearThreadLocalArenas(JSContext *cx, unsigned argc, Value *vp)
 {
     return true;
 }
 static bool
 intrinsic_ClearThreadLocalArenasPar(ForkJoinContext *cx, unsigned argc, Value *vp)
 {
     cx->allocator()->arenas.wipeDuringParallelExecution(cx->runtime());
     return true;
 }
 JS_JITINFO_NATIVE_PARALLEL(js::intrinsic_ClearThreadLocalArenasInfo,
                            intrinsic_ClearThreadLocalArenasPar);
 #endif // JS_THREADSAFE && JS_ION

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js/src/vm/ForkJoin.cpp@6474c204b198 (annotated)

js/src/vm/ForkJoin.cpp