C++ JSFunction::executable方法代码示例

CallLinkStatus CallLinkStatus::computeFor(CodeBlock* profiledBlock, unsigned bytecodeIndex)
{
    ConcurrentJITLocker locker(profiledBlock->m_lock);
    
    UNUSED_PARAM(profiledBlock);
    UNUSED_PARAM(bytecodeIndex);
#if ENABLE(JIT) && ENABLE(VALUE_PROFILER)
    if (!profiledBlock->hasBaselineJITProfiling())
        return computeFromLLInt(profiledBlock, bytecodeIndex);
    
    if (profiledBlock->couldTakeSlowCase(bytecodeIndex))
        return CallLinkStatus::takesSlowPath();
    
    CallLinkInfo& callLinkInfo = profiledBlock->getCallLinkInfo(bytecodeIndex);
    if (callLinkInfo.stub)
        return CallLinkStatus(callLinkInfo.stub->executable(), callLinkInfo.stub->structure());
    
    JSFunction* target = callLinkInfo.lastSeenCallee.get();
    if (!target)
        return computeFromLLInt(profiledBlock, bytecodeIndex);
    
    if (callLinkInfo.hasSeenClosure)
        return CallLinkStatus(target->executable(), target->structure());

    return CallLinkStatus(target);
#else
    return CallLinkStatus();
#endif
}

CallLinkStatus CallLinkStatus::computeFor(const ConcurrentJITLocker&, CallLinkInfo& callLinkInfo)
{
    // Note that despite requiring that the locker is held, this code is racy with respect
    // to the CallLinkInfo: it may get cleared while this code runs! This is because
    // CallLinkInfo::unlink() may be called from a different CodeBlock than the one that owns
    // the CallLinkInfo and currently we save space by not having CallLinkInfos know who owns
    // them. So, there is no way for either the caller of CallLinkInfo::unlock() or unlock()
    // itself to figure out which lock to lock.
    //
    // Fortunately, that doesn't matter. The only things we ask of CallLinkInfo - the slow
    // path count, the stub, and the target - can all be asked racily. Stubs and targets can
    // only be deleted at next GC, so if we load a non-null one, then it must contain data
    // that is still marginally valid (i.e. the pointers ain't stale). This kind of raciness
    // is probably OK for now.

    if (callLinkInfo.slowPathCount >= Options::couldTakeSlowCaseMinimumCount())
        return takesSlowPath();

    if (ClosureCallStubRoutine* stub = callLinkInfo.stub.get())
        return CallLinkStatus(stub->executable(), stub->structure());

    JSFunction* target = callLinkInfo.lastSeenCallee.get();
    if (!target)
        return CallLinkStatus();

    if (callLinkInfo.hasSeenClosure)
        return CallLinkStatus(target->executable(), target->structure());

    return CallLinkStatus(target);
}

static bool attemptToOptimizeClosureCall(ExecState* execCallee, JSCell* calleeAsFunctionCell, CallLinkInfo& callLinkInfo)
{
    if (!calleeAsFunctionCell)
        return false;
    
    JSFunction* callee = jsCast<JSFunction*>(calleeAsFunctionCell);
    JSFunction* oldCallee = callLinkInfo.callee.get();
    
    if (!oldCallee
        || oldCallee->structure() != callee->structure()
        || oldCallee->executable() != callee->executable())
        return false;
    
    ASSERT(callee->executable()->hasJITCodeForCall());
    MacroAssemblerCodePtr codePtr = callee->executable()->generatedJITCodeForCall()->addressForCall();
    
    CodeBlock* codeBlock;
    if (callee->executable()->isHostFunction())
        codeBlock = 0;
    else {
        codeBlock = jsCast<FunctionExecutable*>(callee->executable())->codeBlockForCall();
        if (execCallee->argumentCountIncludingThis() < static_cast<size_t>(codeBlock->numParameters()))
            return false;
    }
    
    linkClosureCall(
        execCallee, callLinkInfo, codeBlock,
        callee->structure(), callee->executable(), codePtr);
    
    return true;
}

inline void Recompiler::operator()(JSCell* cell)
{
    if (!cell->inherits(&JSFunction::s_info))
        return;
    JSFunction* function = asFunction(cell);
    if (function->executable()->isHostFunction())
        return;
    function->jsExecutable()->discardCode();
}

bool CallFrame::isInlineCallFrameSlow()
{
    if (!callee())
        return false;
    JSCell* calleeAsFunctionCell = getJSFunction(callee());
    if (!calleeAsFunctionCell)
        return false;
    JSFunction* calleeAsFunction = asFunction(calleeAsFunctionCell);
    return calleeAsFunction->executable() != codeBlock()->ownerExecutable();
}

FunctionExecutable* getExecutableForFunction(JSValue theFunctionValue)
{
    JSFunction* theFunction = jsDynamicCast<JSFunction*>(theFunctionValue);
    if (!theFunction)
        return 0;
    
    FunctionExecutable* executable = jsDynamicCast<FunctionExecutable*>(
        theFunction->executable());
    return executable;
}

JSValue JITCode::execute(VM* vm, ProtoCallFrame* protoCallFrame)
{
    void* entryAddress;
    JSFunction* function = jsDynamicCast<JSFunction*>(protoCallFrame->callee());

    if (!function || !protoCallFrame->needArityCheck()) {
        ASSERT(!protoCallFrame->needArityCheck());
        entryAddress = executableAddress();
    } else
        entryAddress = addressForCall(*vm, function->executable(), MustCheckArity, RegisterPreservationNotRequired).executableAddress();
    JSValue result = JSValue::decode(vmEntryToJavaScript(entryAddress, vm, protoCallFrame));
    return vm->exception() ? jsNull() : result;
}

static FunctionExecutable* getExecutable(JSContextRef context, JSValueRef theFunctionValueRef)
{
    ExecState* exec = toJS(context);
    JSValue theFunctionValue = toJS(exec, theFunctionValueRef);
    
    JSFunction* theFunction = jsDynamicCast<JSFunction*>(theFunctionValue);
    if (!theFunction)
        return 0;
    
    FunctionExecutable* executable = jsDynamicCast<FunctionExecutable*>(
        theFunction->executable());
    return executable;
}

CallIdentifier Profiler::createCallIdentifier(ExecState* exec, JSValue functionValue, const UString& defaultSourceURL, int defaultLineNumber)
{
    if (!functionValue)
        return CallIdentifier(GlobalCodeExecution, defaultSourceURL, defaultLineNumber);
    if (!functionValue.isObject())
        return CallIdentifier("(unknown)", defaultSourceURL, defaultLineNumber);
    if (asObject(functionValue)->inherits(&JSFunction::info)) {
        JSFunction* function = asFunction(functionValue);
        if (!function->executable()->isHostFunction())
            return createCallIdentifierFromFunctionImp(exec, function);
    }
    if (asObject(functionValue)->inherits(&InternalFunction::info))
        return CallIdentifier(static_cast<InternalFunction*>(asObject(functionValue))->name(exec), defaultSourceURL, defaultLineNumber);
    return CallIdentifier(makeString("(", asObject(functionValue)->className(), " object)"), defaultSourceURL, defaultLineNumber);
}

CallLinkStatus CallLinkStatus::computeFor(const ConcurrentJITLocker&, CallLinkInfo& callLinkInfo)
{
    if (callLinkInfo.slowPathCount >= Options::couldTakeSlowCaseMinimumCount())
        return takesSlowPath();
    
    if (callLinkInfo.stub)
        return CallLinkStatus(callLinkInfo.stub->executable(), callLinkInfo.stub->structure());
    
    JSFunction* target = callLinkInfo.lastSeenCallee.get();
    if (!target)
        return CallLinkStatus();
    
    if (callLinkInfo.hasSeenClosure)
        return CallLinkStatus(target->executable(), target->structure());

    return CallLinkStatus(target);
}

void Debugger::recompileAllJSFunctions(JSGlobalData* globalData)
{
    // If JavaScript is running, it's not safe to recompile, since we'll end
    // up throwing away code that is live on the stack.
    ASSERT(!globalData->dynamicGlobalObject);
    if (globalData->dynamicGlobalObject)
        return;

    typedef HashSet<FunctionExecutable*> FunctionExecutableSet;
    typedef HashMap<SourceProvider*, ExecState*> SourceProviderMap;

    FunctionExecutableSet functionExecutables;
    SourceProviderMap sourceProviders;

    LiveObjectIterator it = globalData->heap.primaryHeapBegin();
    LiveObjectIterator heapEnd = globalData->heap.primaryHeapEnd();
    for ( ; it != heapEnd; ++it) {
        if (!(*it)->inherits(&JSFunction::info))
            continue;

        JSFunction* function = asFunction(*it);
        if (function->executable()->isHostFunction())
            continue;

        FunctionExecutable* executable = function->jsExecutable();

        // Check if the function is already in the set - if so,
        // we've already retranslated it, nothing to do here.
        if (!functionExecutables.add(executable).second)
            continue;

        ExecState* exec = function->scope().globalObject()->JSGlobalObject::globalExec();
        executable->recompile(exec);
        if (function->scope().globalObject()->debugger() == this)
            sourceProviders.add(executable->source().provider(), exec);
    }

    // Call sourceParsed() after reparsing all functions because it will execute
    // JavaScript in the inspector.
    SourceProviderMap::const_iterator end = sourceProviders.end();
    for (SourceProviderMap::const_iterator iter = sourceProviders.begin(); iter != end; ++iter)
        sourceParsed(iter->second, SourceCode(iter->first), -1, UString());
}

EncodedJSValue JSC_HOST_CALL boundThisNoArgsFunctionCall(ExecState* exec)
{
    JSBoundFunction* boundFunction = jsCast<JSBoundFunction*>(exec->jsCallee());

    MarkedArgumentBuffer args;
    for (unsigned i = 0; i < exec->argumentCount(); ++i)
        args.append(exec->uncheckedArgument(i));

    JSFunction* targetFunction = jsCast<JSFunction*>(boundFunction->targetFunction());
    ExecutableBase* executable = targetFunction->executable();
    if (executable->hasJITCodeForCall()) {
        // Force the executable to cache its arity entrypoint.
        executable->entrypointFor(CodeForCall, MustCheckArity);
    }
    CallData callData;
    CallType callType = getCallData(targetFunction, callData);
    ASSERT(callType != CallType::None);
    return JSValue::encode(call(exec, targetFunction, callType, callData, boundFunction->boundThis(), args));
}

inline void* virtualFor(ExecState* execCallee, CodeSpecializationKind kind)
{
    ExecState* exec = execCallee->callerFrame();
    JSValue calleeAsValue = execCallee->calleeAsValue();
    JSCell* calleeAsFunctionCell = getJSFunction(calleeAsValue);
    if (UNLIKELY(!calleeAsFunctionCell))
        return handleHostCall(execCallee, calleeAsValue, kind);
    
    JSFunction* function = asFunction(calleeAsFunctionCell);
    execCallee->setScopeChain(function->scopeUnchecked());
    ExecutableBase* executable = function->executable();
    if (UNLIKELY(!executable->hasJITCodeFor(kind))) {
        FunctionExecutable* functionExecutable = static_cast<FunctionExecutable*>(executable);
        JSObject* error = functionExecutable->compileFor(execCallee, function->scope(), kind);
        if (error) {
            exec->globalData().exception = error;
            return 0;
        }
    }
    return executable->generatedJITCodeWithArityCheckFor(kind).executableAddress();
}

inline void* linkFor(ExecState* execCallee, ReturnAddressPtr returnAddress, CodeSpecializationKind kind)
{
    ExecState* exec = execCallee->callerFrame();
    JSGlobalData* globalData = &exec->globalData();
    NativeCallFrameTracer tracer(globalData, exec);
    
    JSValue calleeAsValue = execCallee->calleeAsValue();
    JSCell* calleeAsFunctionCell = getJSFunction(calleeAsValue);
    if (!calleeAsFunctionCell)
        return handleHostCall(execCallee, calleeAsValue, kind);

    JSFunction* callee = jsCast<JSFunction*>(calleeAsFunctionCell);
    execCallee->setScopeChain(callee->scopeUnchecked());
    ExecutableBase* executable = callee->executable();

    MacroAssemblerCodePtr codePtr;
    CodeBlock* codeBlock = 0;
    if (executable->isHostFunction())
        codePtr = executable->generatedJITCodeFor(kind).addressForCall();
    else {
        FunctionExecutable* functionExecutable = static_cast<FunctionExecutable*>(executable);
        JSObject* error = functionExecutable->compileFor(execCallee, callee->scope(), kind);
        if (error) {
            globalData->exception = createStackOverflowError(exec);
            return 0;
        }
        codeBlock = &functionExecutable->generatedBytecodeFor(kind);
        if (execCallee->argumentCountIncludingThis() < static_cast<size_t>(codeBlock->numParameters()))
            codePtr = functionExecutable->generatedJITCodeWithArityCheckFor(kind);
        else
            codePtr = functionExecutable->generatedJITCodeFor(kind).addressForCall();
    }
    CallLinkInfo& callLinkInfo = exec->codeBlock()->getCallLinkInfo(returnAddress);
    if (!callLinkInfo.seenOnce())
        callLinkInfo.setSeen();
    else
        dfgLinkFor(execCallee, callLinkInfo, codeBlock, callee, codePtr, kind);
    return codePtr.executableAddress();
}

inline char* linkFor(ExecState* execCallee, CodeSpecializationKind kind)
{
    ExecState* exec = execCallee->callerFrame();
    VM* vm = &exec->vm();
    NativeCallFrameTracer tracer(vm, exec);
    
    JSValue calleeAsValue = execCallee->calleeAsValue();
    JSCell* calleeAsFunctionCell = getJSFunction(calleeAsValue);
    if (!calleeAsFunctionCell)
        return reinterpret_cast<char*>(handleHostCall(execCallee, calleeAsValue, kind));

    JSFunction* callee = jsCast<JSFunction*>(calleeAsFunctionCell);
    execCallee->setScope(callee->scopeUnchecked());
    ExecutableBase* executable = callee->executable();

    MacroAssemblerCodePtr codePtr;
    CodeBlock* codeBlock = 0;
    if (executable->isHostFunction())
        codePtr = executable->generatedJITCodeFor(kind)->addressForCall();
    else {
        FunctionExecutable* functionExecutable = static_cast<FunctionExecutable*>(executable);
        JSObject* error = functionExecutable->prepareForExecution(execCallee, callee->scope(), kind);
        if (error) {
            vm->throwException(exec, createStackOverflowError(exec));
            return reinterpret_cast<char*>(vm->getCTIStub(throwExceptionFromCallSlowPathGenerator).code().executableAddress());
        }
        codeBlock = functionExecutable->codeBlockFor(kind);
        if (execCallee->argumentCountIncludingThis() < static_cast<size_t>(codeBlock->numParameters()))
            codePtr = functionExecutable->generatedJITCodeWithArityCheckFor(kind);
        else
            codePtr = functionExecutable->generatedJITCodeFor(kind)->addressForCall();
    }
    CallLinkInfo& callLinkInfo = exec->codeBlock()->getCallLinkInfo(execCallee->returnPC());
    if (!callLinkInfo.seenOnce())
        callLinkInfo.setSeen();
    else
        linkFor(execCallee, callLinkInfo, codeBlock, callee, codePtr, kind);
    return reinterpret_cast<char*>(codePtr.executableAddress());
}