C++ Operands::setOperand方法代码示例

void compileOSRExit(ExecState* exec)
{
    SamplingRegion samplingRegion("DFG OSR Exit Compilation");
    
    CodeBlock* codeBlock = exec->codeBlock();
    
    ASSERT(codeBlock);
    ASSERT(codeBlock->getJITType() == JITCode::DFGJIT);
    
    JSGlobalData* globalData = &exec->globalData();
    
    uint32_t exitIndex = globalData->osrExitIndex;
    OSRExit& exit = codeBlock->osrExit(exitIndex);
    
    // Make sure all code on our inline stack is JIT compiled. This is necessary since
    // we may opt to inline a code block even before it had ever been compiled by the
    // JIT, but our OSR exit infrastructure currently only works if the target of the
    // OSR exit is JIT code. This could be changed since there is nothing particularly
    // hard about doing an OSR exit into the interpreter, but for now this seems to make
    // sense in that if we're OSR exiting from inlined code of a DFG code block, then
    // probably it's a good sign that the thing we're exiting into is hot. Even more
    // interestingly, since the code was inlined, it may never otherwise get JIT
    // compiled since the act of inlining it may ensure that it otherwise never runs.
    for (CodeOrigin codeOrigin = exit.m_codeOrigin; codeOrigin.inlineCallFrame; codeOrigin = codeOrigin.inlineCallFrame->caller) {
        static_cast<FunctionExecutable*>(codeOrigin.inlineCallFrame->executable.get())
            ->baselineCodeBlockFor(codeOrigin.inlineCallFrame->isCall ? CodeForCall : CodeForConstruct)
            ->jitCompile(exec);
    }
    
    // Compute the value recoveries.
    Operands<ValueRecovery> operands;
    codeBlock->variableEventStream().reconstruct(codeBlock, exit.m_codeOrigin, codeBlock->minifiedDFG(), exit.m_streamIndex, operands);
    
    // There may be an override, for forward speculations.
    if (!!exit.m_valueRecoveryOverride) {
        operands.setOperand(
            exit.m_valueRecoveryOverride->operand, exit.m_valueRecoveryOverride->recovery);
    }
    
    SpeculationRecovery* recovery = 0;
    if (exit.m_recoveryIndex)
        recovery = &codeBlock->speculationRecovery(exit.m_recoveryIndex - 1);

#if DFG_ENABLE(DEBUG_VERBOSE)
    dataLog(
        "Generating OSR exit #", exitIndex, " (seq#", exit.m_streamIndex,
        ", bc#", exit.m_codeOrigin.bytecodeIndex, ", @", exit.m_nodeIndex, ", ",
        exit.m_kind, ") for ", *codeBlock, ".\n");
#endif

    {
        CCallHelpers jit(globalData, codeBlock);
        OSRExitCompiler exitCompiler(jit);

        jit.jitAssertHasValidCallFrame();
        
        if (globalData->m_perBytecodeProfiler && codeBlock->compilation()) {
            Profiler::Database& database = *globalData->m_perBytecodeProfiler;
            Profiler::Compilation* compilation = codeBlock->compilation();
            
            Profiler::OSRExit* profilerExit = compilation->addOSRExit(
                exitIndex, Profiler::OriginStack(database, codeBlock, exit.m_codeOrigin),
                exit.m_kind,
                exit.m_watchpointIndex != std::numeric_limits<unsigned>::max());
            jit.add64(CCallHelpers::TrustedImm32(1), CCallHelpers::AbsoluteAddress(profilerExit->counterAddress()));
        }
        
        exitCompiler.compileExit(exit, operands, recovery);
        
        LinkBuffer patchBuffer(*globalData, &jit, codeBlock);
        exit.m_code = FINALIZE_CODE_IF(
            shouldShowDisassembly(),
            patchBuffer,
            ("DFG OSR exit #%u (bc#%u, @%u, %s) from %s",
                exitIndex, exit.m_codeOrigin.bytecodeIndex, exit.m_nodeIndex,
                exitKindToString(exit.m_kind), toCString(*codeBlock).data()));
    }
    
    {
        RepatchBuffer repatchBuffer(codeBlock);
        repatchBuffer.relink(exit.codeLocationForRepatch(codeBlock), CodeLocationLabel(exit.m_code.code()));
    }
    
    globalData->osrExitJumpDestination = exit.m_code.code().executableAddress();
}

void compileOSRExit(ExecState* exec)
{
    SamplingRegion samplingRegion("DFG OSR Exit Compilation");
    
    CodeBlock* codeBlock = exec->codeBlock();
    
    ASSERT(codeBlock);
    ASSERT(codeBlock->jitType() == JITCode::DFGJIT);
    
    VM* vm = &exec->vm();
    
    // It's sort of preferable that we don't GC while in here. Anyways, doing so wouldn't
    // really be profitable.
    DeferGCForAWhile deferGC(vm->heap);

    uint32_t exitIndex = vm->osrExitIndex;
    OSRExit& exit = codeBlock->jitCode()->dfg()->osrExit[exitIndex];
    
    prepareCodeOriginForOSRExit(exec, exit.m_codeOrigin);
    
    // Compute the value recoveries.
    Operands<ValueRecovery> operands;
    codeBlock->jitCode()->dfg()->variableEventStream.reconstruct(codeBlock, exit.m_codeOrigin, codeBlock->jitCode()->dfg()->minifiedDFG, exit.m_streamIndex, operands);
    
    // There may be an override, for forward speculations.
    if (!!exit.m_valueRecoveryOverride) {
        operands.setOperand(
            exit.m_valueRecoveryOverride->operand, exit.m_valueRecoveryOverride->recovery);
    }
    
    SpeculationRecovery* recovery = 0;
    if (exit.m_recoveryIndex != UINT_MAX)
        recovery = &codeBlock->jitCode()->dfg()->speculationRecovery[exit.m_recoveryIndex];

    {
        CCallHelpers jit(vm, codeBlock);
        OSRExitCompiler exitCompiler(jit);

        jit.jitAssertHasValidCallFrame();
        
        if (vm->m_perBytecodeProfiler && codeBlock->jitCode()->dfgCommon()->compilation) {
            Profiler::Database& database = *vm->m_perBytecodeProfiler;
            Profiler::Compilation* compilation = codeBlock->jitCode()->dfgCommon()->compilation.get();
            
            Profiler::OSRExit* profilerExit = compilation->addOSRExit(
                exitIndex, Profiler::OriginStack(database, codeBlock, exit.m_codeOrigin),
                exit.m_kind, exit.m_kind == UncountableInvalidation);
            jit.add64(CCallHelpers::TrustedImm32(1), CCallHelpers::AbsoluteAddress(profilerExit->counterAddress()));
        }
        
        exitCompiler.compileExit(exit, operands, recovery);
        
        LinkBuffer patchBuffer(*vm, jit, codeBlock);
        exit.m_code = FINALIZE_CODE_IF(
            shouldShowDisassembly() || Options::verboseOSR(),
            patchBuffer,
            ("DFG OSR exit #%u (%s, %s) from %s, with operands = %s",
                exitIndex, toCString(exit.m_codeOrigin).data(),
                exitKindToString(exit.m_kind), toCString(*codeBlock).data(),
                toCString(ignoringContext<DumpContext>(operands)).data()));
    }
    
    {
        RepatchBuffer repatchBuffer(codeBlock);
        repatchBuffer.relink(exit.codeLocationForRepatch(codeBlock), CodeLocationLabel(exit.m_code.code()));
    }
    
    vm->osrExitJumpDestination = exit.m_code.code().executableAddress();
}