Source/JavaScriptCore/dfg/DFGJITCode.cpp

/*
 * Copyright (C) 2013 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#include "config.h"
#include "DFGJITCode.h"

#if ENABLE(DFG_JIT)

#include "CodeBlock.h"

namespace JSC { namespace DFG {

JITCode::JITCode()
    : DirectJITCode(DFGJIT)
{
}

JITCode::~JITCode()
{
}

CommonData* JITCode::dfgCommon()
{
    return &common;
}

JITCode* JITCode::dfg()
{
    return this;
}

void JITCode::shrinkToFit()
{
    common.shrinkToFit();
    osrEntry.shrinkToFit();
    osrExit.shrinkToFit();
    speculationRecovery.shrinkToFit();
    minifiedDFG.prepareAndShrink();
    variableEventStream.shrinkToFit();
}

void JITCode::reconstruct(
    CodeBlock* codeBlock, CodeOrigin codeOrigin, unsigned streamIndex,
    Operands<ValueRecovery>& result)
{
    variableEventStream.reconstruct(
        codeBlock, codeOrigin, minifiedDFG, streamIndex, result);
}

void JITCode::reconstruct(
    ExecState* exec, CodeBlock* codeBlock, CodeOrigin codeOrigin, unsigned streamIndex,
    Operands<JSValue>& result)
{
    Operands<ValueRecovery> recoveries;
    reconstruct(codeBlock, codeOrigin, streamIndex, recoveries);
    
    result = Operands<JSValue>(OperandsLike, recoveries);
    for (size_t i = result.size(); i--;) {
        int operand = result.operandForIndex(i);
        
        if (operandIsArgument(operand)
            && !VirtualRegister(operand).toArgument()
            && codeBlock->codeType() == FunctionCode
            && codeBlock->specializationKind() == CodeForConstruct) {
            // Ugh. If we're in a constructor, the 'this' argument may hold garbage. It will
            // also never be used. It doesn't matter what we put into the value for this,
            // but it has to be an actual value that can be grokked by subsequent DFG passes,
            // so we sanitize it here by turning it into Undefined.
            result[i] = jsUndefined();
            continue;
        }
        
        result[i] = recoveries[i].recover(exec);
    }
}

#if ENABLE(FTL_JIT)
bool JITCode::checkIfOptimizationThresholdReached(CodeBlock* codeBlock)
{
    ASSERT(codeBlock->jitType() == JITCode::DFGJIT);
    return tierUpCounter.checkIfThresholdCrossedAndSet(codeBlock->baselineVersion());
}

void JITCode::optimizeNextInvocation(CodeBlock* codeBlock)
{
    ASSERT(codeBlock->jitType() == JITCode::DFGJIT);
    if (Options::verboseOSR())
        dataLog(*codeBlock, ": FTL-optimizing next invocation.\n");
    tierUpCounter.setNewThreshold(0, codeBlock->baselineVersion());
}

void JITCode::dontOptimizeAnytimeSoon(CodeBlock* codeBlock)
{
    ASSERT(codeBlock->jitType() == JITCode::DFGJIT);
    if (Options::verboseOSR())
        dataLog(*codeBlock, ": Not FTL-optimizing anytime soon.\n");
    tierUpCounter.deferIndefinitely();
}

void JITCode::optimizeAfterWarmUp(CodeBlock* codeBlock)
{
    ASSERT(codeBlock->jitType() == JITCode::DFGJIT);
    if (Options::verboseOSR())
        dataLog(*codeBlock, ": FTL-optimizing after warm-up.\n");
    CodeBlock* baseline = codeBlock->baselineVersion();
    tierUpCounter.setNewThreshold(
        baseline->adjustedCounterValue(Options::thresholdForFTLOptimizeAfterWarmUp()),
        baseline);
}

void JITCode::optimizeSoon(CodeBlock* codeBlock)
{
    ASSERT(codeBlock->jitType() == JITCode::DFGJIT);
    if (Options::verboseOSR())
        dataLog(*codeBlock, ": FTL-optimizing soon.\n");
    CodeBlock* baseline = codeBlock->baselineVersion();
    tierUpCounter.setNewThreshold(
        baseline->adjustedCounterValue(Options::thresholdForFTLOptimizeSoon()),
        baseline);
}

void JITCode::forceOptimizationSlowPathConcurrently(CodeBlock* codeBlock)
{
    ASSERT(codeBlock->jitType() == JITCode::DFGJIT);
    if (Options::verboseOSR())
        dataLog(*codeBlock, ": Forcing slow path concurrently for FTL entry.\n");
    tierUpCounter.forceSlowPathConcurrently();
}

void JITCode::setOptimizationThresholdBasedOnCompilationResult(
    CodeBlock* codeBlock, CompilationResult result)
{
    ASSERT(codeBlock->jitType() == JITCode::DFGJIT);
    switch (result) {
    case CompilationSuccessful:
        optimizeNextInvocation(codeBlock);
        return;
    case CompilationFailed:
        dontOptimizeAnytimeSoon(codeBlock);
        codeBlock->baselineVersion()->m_didFailFTLCompilation = true;
        return;
    case CompilationDeferred:
        optimizeAfterWarmUp(codeBlock);
        return;
    case CompilationInvalidated:
        // This is weird - it will only happen in cases when the DFG code block (i.e.
        // the code block that this JITCode belongs to) is also invalidated. So it
        // doesn't really matter what we do. But, we do the right thing anyway. Note
        // that us counting the reoptimization actually means that we might count it
        // twice. But that's generally OK. It's better to overcount reoptimizations
        // than it is to undercount them.
        codeBlock->baselineVersion()->countReoptimization();
        optimizeAfterWarmUp(codeBlock);
        return;
    }
    RELEASE_ASSERT_NOT_REACHED();
}
#endif // ENABLE(FTL_JIT)

} } // namespace JSC::DFG

#endif // ENABLE(DFG_JIT)