src/third_party/WebKit/Source/JavaScriptCore/runtime/Executable.cpp

/*
 * Copyright (C) 2009, 2010 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 "Executable.h"

#include "BatchedTransitionOptimizer.h"
#include "BytecodeGenerator.h"
#include "CodeBlock.h"
#include "DFGDriver.h"
#include "ExecutionHarness.h"
#include "JIT.h"
#include "JITDriver.h"
#include "Parser.h"
#include <wtf/Vector.h>
#include <wtf/text/StringBuilder.h>

namespace JSC {

const ClassInfo ExecutableBase::s_info = { "Executable", 0, 0, 0, CREATE_METHOD_TABLE(ExecutableBase) };
const ClassInfo* ExecutableBase::s_classinfo() {return &s_info;}

void ExecutableBase::destroy(JSCell* cell)
{
    static_cast<ExecutableBase*>(cell)->ExecutableBase::~ExecutableBase();
}

void ExecutableBase::clearCode()
{
#if ENABLE(JIT)
    m_jitCodeForCall.clear();
    m_jitCodeForConstruct.clear();
    m_jitCodeForCallWithArityCheck = MacroAssemblerCodePtr();
    m_jitCodeForConstructWithArityCheck = MacroAssemblerCodePtr();
#endif
    m_numParametersForCall = NUM_PARAMETERS_NOT_COMPILED;
    m_numParametersForConstruct = NUM_PARAMETERS_NOT_COMPILED;
}

#if ENABLE(DFG_JIT)
Intrinsic ExecutableBase::intrinsic() const
{
    if (const NativeExecutable* nativeExecutable = jsDynamicCast<const NativeExecutable*>(this))
        return nativeExecutable->intrinsic();
    return NoIntrinsic;
}
#endif

const ClassInfo NativeExecutable::s_info = { "NativeExecutable", ExecutableBase::s_classinfo(), 0, 0, CREATE_METHOD_TABLE(NativeExecutable) };

void NativeExecutable::destroy(JSCell* cell)
{
    static_cast<NativeExecutable*>(cell)->NativeExecutable::~NativeExecutable();
}

#if ENABLE(DFG_JIT)
Intrinsic NativeExecutable::intrinsic() const
{
    return m_intrinsic;
}
#endif

#if ENABLE(JIT)
// Utility method used for jettisoning code blocks.
template<typename T>
static void jettisonCodeBlock(JSGlobalData& globalData, OwnPtr<T>& codeBlock)
{
    ASSERT(JITCode::isOptimizingJIT(codeBlock->getJITType()));
    ASSERT(codeBlock->alternative());
    OwnPtr<T> codeBlockToJettison = codeBlock.release();
    codeBlock = static_pointer_cast<T>(codeBlockToJettison->releaseAlternative());
    codeBlockToJettison->unlinkIncomingCalls();
    globalData.heap.jettisonDFGCodeBlock(static_pointer_cast<CodeBlock>(codeBlockToJettison.release()));
}
#endif

const ClassInfo ScriptExecutable::s_info = { "ScriptExecutable", ExecutableBase::s_classinfo(), 0, 0, CREATE_METHOD_TABLE(ScriptExecutable) };

void ScriptExecutable::destroy(JSCell* cell)
{
    static_cast<ScriptExecutable*>(cell)->ScriptExecutable::~ScriptExecutable();
}

const ClassInfo EvalExecutable::s_info = { "EvalExecutable", ScriptExecutable::s_classinfo(), 0, 0, CREATE_METHOD_TABLE(EvalExecutable) };

EvalExecutable::EvalExecutable(ExecState* exec, const SourceCode& source, bool inStrictContext)
    : ScriptExecutable(exec->globalData().evalExecutableStructure.get(), exec, source, inStrictContext)
{
}

void EvalExecutable::destroy(JSCell* cell)
{
    static_cast<EvalExecutable*>(cell)->EvalExecutable::~EvalExecutable();
}

const ClassInfo ProgramExecutable::s_info = { "ProgramExecutable", ScriptExecutable::s_classinfo(), 0, 0, CREATE_METHOD_TABLE(ProgramExecutable) };

ProgramExecutable::ProgramExecutable(ExecState* exec, const SourceCode& source)
    : ScriptExecutable(exec->globalData().programExecutableStructure.get(), exec, source, false)
{
}

void ProgramExecutable::destroy(JSCell* cell)
{
    static_cast<ProgramExecutable*>(cell)->ProgramExecutable::~ProgramExecutable();
}

const ClassInfo FunctionExecutable::s_info = { "FunctionExecutable", ScriptExecutable::s_classinfo(), 0, 0, CREATE_METHOD_TABLE(FunctionExecutable) };
const ClassInfo* FunctionExecutable::s_classinfo() {return &s_info;}

FunctionExecutable::FunctionExecutable(JSGlobalData& globalData, const SourceCode& source, UnlinkedFunctionExecutable* unlinkedExecutable, unsigned firstLine, unsigned lastLine)
    : ScriptExecutable(globalData.functionExecutableStructure.get(), globalData, source, unlinkedExecutable->isInStrictContext())
    , m_unlinkedExecutable(globalData, this, unlinkedExecutable)
{
    ASSERT(!source.isNull());
    ASSERT(source.length());
    m_firstLine = firstLine;
    m_lastLine = lastLine;
}

void FunctionExecutable::destroy(JSCell* cell)
{
    static_cast<FunctionExecutable*>(cell)->FunctionExecutable::~FunctionExecutable();
}

JSObject* EvalExecutable::compileOptimized(ExecState* exec, JSScope* scope, unsigned bytecodeIndex)
{
    ASSERT(exec->globalData().dynamicGlobalObject);
    ASSERT(!!m_evalCodeBlock);
    JSObject* error = 0;
    if (m_evalCodeBlock->getJITType() != JITCode::topTierJIT())
        error = compileInternal(exec, scope, JITCode::nextTierJIT(m_evalCodeBlock->getJITType()), bytecodeIndex);
    ASSERT(!!m_evalCodeBlock);
    return error;
}

#if ENABLE(JIT)
bool EvalExecutable::jitCompile(ExecState* exec)
{
    return jitCompileIfAppropriate(exec, m_evalCodeBlock, m_jitCodeForCall, JITCode::bottomTierJIT(), UINT_MAX, JITCompilationCanFail);
}
#endif

inline const char* samplingDescription(JITCode::JITType jitType)
{
    switch (jitType) {
    case JITCode::InterpreterThunk:
        return "Interpreter Compilation (TOTAL)";
    case JITCode::BaselineJIT:
        return "Baseline Compilation (TOTAL)";
    case JITCode::DFGJIT:
        return "DFG Compilation (TOTAL)";
    default:
        ASSERT_NOT_REACHED();
        return 0;
    }
}

JSObject* EvalExecutable::compileInternal(ExecState* exec, JSScope* scope, JITCode::JITType jitType, unsigned bytecodeIndex)
{
    SamplingRegion samplingRegion(samplingDescription(jitType));
    
#if !ENABLE(JIT)
    UNUSED_PARAM(jitType);
    UNUSED_PARAM(bytecodeIndex);
#endif
    JSGlobalData* globalData = &exec->globalData();
    JSGlobalObject* lexicalGlobalObject = exec->lexicalGlobalObject();
    
    if (!!m_evalCodeBlock) {
        OwnPtr<EvalCodeBlock> newCodeBlock = adoptPtr(new EvalCodeBlock(CodeBlock::CopyParsedBlock, *m_evalCodeBlock));
        newCodeBlock->setAlternative(static_pointer_cast<CodeBlock>(m_evalCodeBlock.release()));
        m_evalCodeBlock = newCodeBlock.release();
    } else {
        UNUSED_PARAM(scope);
        UNUSED_PARAM(globalData);
        UNUSED_PARAM(lexicalGlobalObject);
#if defined(COBALT)
        const bool evalEnabled = lexicalGlobalObject->checkEvalEnabledAndReport();
#else
        const bool evalEnabled = lexicalGlobalObject->evalEnabled();
#endif
        if (!evalEnabled)
            return throwError(exec, createEvalError(exec, lexicalGlobalObject->evalDisabledErrorMessage()));

        JSObject* exception = 0;
        UnlinkedEvalCodeBlock* unlinkedEvalCode = lexicalGlobalObject->createEvalCodeBlock(exec, this, &exception);
        if (!unlinkedEvalCode)
            return exception;

        OwnPtr<CodeBlock> previousCodeBlock = m_evalCodeBlock.release();
        ASSERT((jitType == JITCode::bottomTierJIT()) == !previousCodeBlock);
        m_unlinkedEvalCodeBlock.set(*globalData, this, unlinkedEvalCode);
        m_evalCodeBlock = adoptPtr(new EvalCodeBlock(this, unlinkedEvalCode, lexicalGlobalObject, source().provider(), scope->localDepth(), previousCodeBlock.release()));
        m_evalCodeBlock->copyPostParseDataFromAlternative();
    }

#if ENABLE(JIT)
    if (!prepareForExecution(exec, m_evalCodeBlock, m_jitCodeForCall, jitType, bytecodeIndex))
        return 0;
#endif

#if ENABLE(JIT)
    Heap::heap(this)->reportExtraMemoryCost(sizeof(*m_evalCodeBlock) + m_jitCodeForCall.size());
#else
    Heap::heap(this)->reportExtraMemoryCost(sizeof(*m_evalCodeBlock));
#endif

    return 0;
}

#if ENABLE(JIT)
void EvalExecutable::jettisonOptimizedCode(JSGlobalData& globalData)
{
    jettisonCodeBlock(globalData, m_evalCodeBlock);
    m_jitCodeForCall = m_evalCodeBlock->getJITCode();
    ASSERT(!m_jitCodeForCallWithArityCheck);
}
#endif

void EvalExecutable::visitChildren(JSCell* cell, SlotVisitor& visitor)
{
    EvalExecutable* thisObject = jsCast<EvalExecutable*>(cell);
    ASSERT_GC_OBJECT_INHERITS(thisObject, &s_info);
    COMPILE_ASSERT(StructureFlags & OverridesVisitChildren, OverridesVisitChildrenWithoutSettingFlag);
    ASSERT(thisObject->structure()->typeInfo().overridesVisitChildren());
    ScriptExecutable::visitChildren(thisObject, visitor);
    if (thisObject->m_evalCodeBlock)
        thisObject->m_evalCodeBlock->visitAggregate(visitor);
    visitor.append(&thisObject->m_unlinkedEvalCodeBlock);
}

void EvalExecutable::unlinkCalls()
{
#if ENABLE(JIT)
    if (!m_jitCodeForCall)
        return;
    ASSERT(m_evalCodeBlock);
    m_evalCodeBlock->unlinkCalls();
#endif
}

void EvalExecutable::clearCode()
{
    m_evalCodeBlock.clear();
    m_unlinkedEvalCodeBlock.clear();
    Base::clearCode();
}

JSObject* ProgramExecutable::checkSyntax(ExecState* exec)
{
    ParserError error;
    JSGlobalData* globalData = &exec->globalData();
    JSGlobalObject* lexicalGlobalObject = exec->lexicalGlobalObject();
    RefPtr<ProgramNode> programNode = parse<ProgramNode>(globalData, m_source, 0, Identifier(), JSParseNormal, ProgramNode::isFunctionNode ? JSParseFunctionCode : JSParseProgramCode, error);
    if (programNode)
        return 0;
    ASSERT(error.m_type != ParserError::ErrorNone);
    return error.toErrorObject(lexicalGlobalObject, m_source);
}

JSObject* ProgramExecutable::compileOptimized(ExecState* exec, JSScope* scope, unsigned bytecodeIndex)
{
    ASSERT(exec->globalData().dynamicGlobalObject);
    ASSERT(!!m_programCodeBlock);
    JSObject* error = 0;
    if (m_programCodeBlock->getJITType() != JITCode::topTierJIT())
        error = compileInternal(exec, scope, JITCode::nextTierJIT(m_programCodeBlock->getJITType()), bytecodeIndex);
    ASSERT(!!m_programCodeBlock);
    return error;
}

#if ENABLE(JIT)
bool ProgramExecutable::jitCompile(ExecState* exec)
{
    return jitCompileIfAppropriate(exec, m_programCodeBlock, m_jitCodeForCall, JITCode::bottomTierJIT(), UINT_MAX, JITCompilationCanFail);
}
#endif

JSObject* ProgramExecutable::compileInternal(ExecState* exec, JSScope* scope, JITCode::JITType jitType, unsigned bytecodeIndex)
{
    SamplingRegion samplingRegion(samplingDescription(jitType));
    
#if !ENABLE(JIT)
    UNUSED_PARAM(exec);
    UNUSED_PARAM(jitType);
    UNUSED_PARAM(bytecodeIndex);
#endif
    if (!!m_programCodeBlock) {
        OwnPtr<ProgramCodeBlock> newCodeBlock = adoptPtr(new ProgramCodeBlock(CodeBlock::CopyParsedBlock, *m_programCodeBlock));
        newCodeBlock->setAlternative(static_pointer_cast<CodeBlock>(m_programCodeBlock.release()));
        m_programCodeBlock = newCodeBlock.release();
    } else {
        JSGlobalObject* globalObject = scope->globalObject();
        m_programCodeBlock = adoptPtr(new ProgramCodeBlock(this, m_unlinkedProgramCodeBlock.get(), globalObject, source().provider(), m_programCodeBlock.release()));
        m_programCodeBlock->copyPostParseDataFromAlternative();
    }

#if ENABLE(JIT)
    if (!prepareForExecution(exec, m_programCodeBlock, m_jitCodeForCall, jitType, bytecodeIndex))
        return 0;
#endif

#if ENABLE(JIT)
    Heap::heap(this)->reportExtraMemoryCost(sizeof(*m_programCodeBlock) + m_jitCodeForCall.size());
#else
    Heap::heap(this)->reportExtraMemoryCost(sizeof(*m_programCodeBlock));
#endif

    return 0;
}

#if ENABLE(JIT)
void ProgramExecutable::jettisonOptimizedCode(JSGlobalData& globalData)
{
    jettisonCodeBlock(globalData, m_programCodeBlock);
    m_jitCodeForCall = m_programCodeBlock->getJITCode();
    ASSERT(!m_jitCodeForCallWithArityCheck);
}
#endif

void ProgramExecutable::unlinkCalls()
{
#if ENABLE(JIT)
    if (!m_jitCodeForCall)
        return;
    ASSERT(m_programCodeBlock);
    m_programCodeBlock->unlinkCalls();
#endif
}

int ProgramExecutable::addGlobalVar(JSGlobalObject* globalObject, const Identifier& ident, ConstantMode constantMode, FunctionMode functionMode)
{
    // Try to share the symbolTable if possible
    SharedSymbolTable* symbolTable = globalObject->symbolTable();
    UNUSED_PARAM(functionMode);
    int index = symbolTable->size();
    SymbolTableEntry newEntry(index, (constantMode == IsConstant) ? ReadOnly : 0);
    if (functionMode == IsFunctionToSpecialize)
        newEntry.attemptToWatch();
    SymbolTable::AddResult result = symbolTable->add(ident.impl(), newEntry);
    if (!result.isNewEntry) {
        result.iterator->value.notifyWrite();
        index = result.iterator->value.getIndex();
    }
    return index;
}

JSObject* ProgramExecutable::initalizeGlobalProperties(JSGlobalData& globalData, CallFrame* callFrame, JSScope* scope)
{
    ASSERT(scope);
    JSGlobalObject* globalObject = scope->globalObject();
    ASSERT(globalObject);
    ASSERT(&globalObject->globalData() == &globalData);

    JSObject* exception = 0;
    UnlinkedProgramCodeBlock* unlinkedCode = globalObject->createProgramCodeBlock(callFrame, this, &exception);
    if (exception)
        return exception;

    m_unlinkedProgramCodeBlock.set(globalData, this, unlinkedCode);

    BatchedTransitionOptimizer optimizer(globalData, globalObject);

    const UnlinkedProgramCodeBlock::VariableDeclations& variableDeclarations = unlinkedCode->variableDeclarations();
    const UnlinkedProgramCodeBlock::FunctionDeclations& functionDeclarations = unlinkedCode->functionDeclarations();

    size_t newGlobals = variableDeclarations.size() + functionDeclarations.size();
    if (!newGlobals)
        return 0;
    globalObject->addRegisters(newGlobals);
    CallFrame* globalExec = globalObject->globalExec();

    for (size_t i = 0; i < functionDeclarations.size(); ++i) {
        bool propertyDidExist = globalObject->removeDirect(globalData, functionDeclarations[i].first); // Newly declared functions overwrite existing properties.
        UnlinkedFunctionExecutable* unlinkedFunctionExecutable = functionDeclarations[i].second.get();
        JSValue value = JSFunction::create(globalExec, unlinkedFunctionExecutable->link(globalData, m_source, lineNo(), 0), scope);
        int index = addGlobalVar(globalObject, functionDeclarations[i].first, IsVariable,
            !propertyDidExist ? IsFunctionToSpecialize : NotFunctionOrNotSpecializable);
        globalObject->registerAt(index).set(globalData, globalObject, value);
    }

    for (size_t i = 0; i < variableDeclarations.size(); ++i) {
        if (globalObject->hasProperty(globalExec, variableDeclarations[i].first))
            continue;
        addGlobalVar(globalObject, variableDeclarations[i].first,
            (variableDeclarations[i].second & DeclarationStacks::IsConstant) ? IsConstant : IsVariable,
            NotFunctionOrNotSpecializable);
    }
    return 0;
}

void ProgramExecutable::visitChildren(JSCell* cell, SlotVisitor& visitor)
{
    ProgramExecutable* thisObject = jsCast<ProgramExecutable*>(cell);
    ASSERT_GC_OBJECT_INHERITS(thisObject, &s_info);
    COMPILE_ASSERT(StructureFlags & OverridesVisitChildren, OverridesVisitChildrenWithoutSettingFlag);
    ASSERT(thisObject->structure()->typeInfo().overridesVisitChildren());
    ScriptExecutable::visitChildren(thisObject, visitor);
    visitor.append(&thisObject->m_unlinkedProgramCodeBlock);
    if (thisObject->m_programCodeBlock)
        thisObject->m_programCodeBlock->visitAggregate(visitor);
}

void ProgramExecutable::clearCode()
{
    m_programCodeBlock.clear();
    m_unlinkedProgramCodeBlock.clear();
    Base::clearCode();
}

FunctionCodeBlock* FunctionExecutable::baselineCodeBlockFor(CodeSpecializationKind kind)
{
    FunctionCodeBlock* result;
    if (kind == CodeForCall)
        result = m_codeBlockForCall.get();
    else {
        ASSERT(kind == CodeForConstruct);
        result = m_codeBlockForConstruct.get();
    }
    if (!result)
        return 0;
    while (result->alternative())
        result = static_cast<FunctionCodeBlock*>(result->alternative());
    ASSERT(result);
    ASSERT(JITCode::isBaselineCode(result->getJITType()));
    return result;
}

JSObject* FunctionExecutable::compileOptimizedForCall(ExecState* exec, JSScope* scope, unsigned bytecodeIndex)
{
    ASSERT(exec->globalData().dynamicGlobalObject);
    ASSERT(!!m_codeBlockForCall);
    JSObject* error = 0;
    if (m_codeBlockForCall->getJITType() != JITCode::topTierJIT())
        error = compileForCallInternal(exec, scope, JITCode::nextTierJIT(m_codeBlockForCall->getJITType()), bytecodeIndex);
    ASSERT(!!m_codeBlockForCall);
    return error;
}

JSObject* FunctionExecutable::compileOptimizedForConstruct(ExecState* exec, JSScope* scope, unsigned bytecodeIndex)
{
    ASSERT(exec->globalData().dynamicGlobalObject);
    ASSERT(!!m_codeBlockForConstruct);
    JSObject* error = 0;
    if (m_codeBlockForConstruct->getJITType() != JITCode::topTierJIT())
        error = compileForConstructInternal(exec, scope, JITCode::nextTierJIT(m_codeBlockForConstruct->getJITType()), bytecodeIndex);
    ASSERT(!!m_codeBlockForConstruct);
    return error;
}

#if ENABLE(JIT)
bool FunctionExecutable::jitCompileForCall(ExecState* exec)
{
    return jitCompileFunctionIfAppropriate(exec, m_codeBlockForCall, m_jitCodeForCall, m_jitCodeForCallWithArityCheck, JITCode::bottomTierJIT(), UINT_MAX, JITCompilationCanFail);
}

bool FunctionExecutable::jitCompileForConstruct(ExecState* exec)
{
    return jitCompileFunctionIfAppropriate(exec, m_codeBlockForConstruct, m_jitCodeForConstruct, m_jitCodeForConstructWithArityCheck, JITCode::bottomTierJIT(), UINT_MAX, JITCompilationCanFail);
}
#endif

FunctionCodeBlock* FunctionExecutable::codeBlockWithBytecodeFor(CodeSpecializationKind kind)
{
    return baselineCodeBlockFor(kind);
}

PassOwnPtr<FunctionCodeBlock> FunctionExecutable::produceCodeBlockFor(JSScope* scope, CodeSpecializationKind specializationKind, JSObject*& exception)
{
    if (!!codeBlockFor(specializationKind))
        return adoptPtr(new FunctionCodeBlock(CodeBlock::CopyParsedBlock, *codeBlockFor(specializationKind)));

    JSGlobalData* globalData = scope->globalData();
    JSGlobalObject* globalObject = scope->globalObject();
    ParserError error;
    DebuggerMode debuggerMode = globalObject->hasDebugger() ? DebuggerOn : DebuggerOff;
    ProfilerMode profilerMode = globalObject->hasProfiler() ? ProfilerOn : ProfilerOff;
    UnlinkedFunctionCodeBlock* unlinkedCodeBlock = m_unlinkedExecutable->codeBlockFor(*globalData, m_source, specializationKind, debuggerMode, profilerMode, error);
    recordParse(m_unlinkedExecutable->features(), m_unlinkedExecutable->hasCapturedVariables(), lineNo(), lastLine());

    if (!unlinkedCodeBlock) {
        exception = error.toErrorObject(globalObject, m_source);
        return nullptr;
    }

    OwnPtr<FunctionCodeBlock> result = adoptPtr(new FunctionCodeBlock(this, unlinkedCodeBlock, globalObject, source().provider(), source().startOffset()));
    result->copyPostParseDataFrom(codeBlockFor(specializationKind).get());
    return result.release();
}


JSObject* FunctionExecutable::compileForCallInternal(ExecState* exec, JSScope* scope, JITCode::JITType jitType, unsigned bytecodeIndex)
{
    SamplingRegion samplingRegion(samplingDescription(jitType));
    
#if !ENABLE(JIT)
    UNUSED_PARAM(exec);
    UNUSED_PARAM(jitType);
    UNUSED_PARAM(exec);
    UNUSED_PARAM(bytecodeIndex);
#endif
    ASSERT((jitType == JITCode::bottomTierJIT()) == !m_codeBlockForCall);
    JSObject* exception;
    OwnPtr<FunctionCodeBlock> newCodeBlock = produceCodeBlockFor(scope, CodeForCall, exception);
    if (!newCodeBlock)
        return exception;

    newCodeBlock->setAlternative(static_pointer_cast<CodeBlock>(m_codeBlockForCall.release()));
    m_codeBlockForCall = newCodeBlock.release();
    
    m_numParametersForCall = m_codeBlockForCall->numParameters();
    ASSERT(m_numParametersForCall);

#if ENABLE(JIT)
    if (!prepareFunctionForExecution(exec, m_codeBlockForCall, m_jitCodeForCall, m_jitCodeForCallWithArityCheck, jitType, bytecodeIndex, CodeForCall))
        return 0;
#endif

#if ENABLE(JIT)
    Heap::heap(this)->reportExtraMemoryCost(sizeof(*m_codeBlockForCall) + m_jitCodeForCall.size());
#else
    Heap::heap(this)->reportExtraMemoryCost(sizeof(*m_codeBlockForCall));
#endif

    return 0;
}

JSObject* FunctionExecutable::compileForConstructInternal(ExecState* exec, JSScope* scope, JITCode::JITType jitType, unsigned bytecodeIndex)
{
    SamplingRegion samplingRegion(samplingDescription(jitType));
    
#if !ENABLE(JIT)
    UNUSED_PARAM(jitType);
    UNUSED_PARAM(exec);
    UNUSED_PARAM(bytecodeIndex);
#endif
    
    ASSERT((jitType == JITCode::bottomTierJIT()) == !m_codeBlockForConstruct);
    JSObject* exception;
    OwnPtr<FunctionCodeBlock> newCodeBlock = produceCodeBlockFor(scope, CodeForConstruct, exception);
    if (!newCodeBlock)
        return exception;

    newCodeBlock->setAlternative(static_pointer_cast<CodeBlock>(m_codeBlockForConstruct.release()));
    m_codeBlockForConstruct = newCodeBlock.release();
    
    m_numParametersForConstruct = m_codeBlockForConstruct->numParameters();
    ASSERT(m_numParametersForConstruct);

#if ENABLE(JIT)
    if (!prepareFunctionForExecution(exec, m_codeBlockForConstruct, m_jitCodeForConstruct, m_jitCodeForConstructWithArityCheck, jitType, bytecodeIndex, CodeForConstruct))
        return 0;
#endif

#if ENABLE(JIT)
    Heap::heap(this)->reportExtraMemoryCost(sizeof(*m_codeBlockForConstruct) + m_jitCodeForConstruct.size());
#else
    Heap::heap(this)->reportExtraMemoryCost(sizeof(*m_codeBlockForConstruct));
#endif

    return 0;
}

#if ENABLE(JIT)
void FunctionExecutable::jettisonOptimizedCodeForCall(JSGlobalData& globalData)
{
    jettisonCodeBlock(globalData, m_codeBlockForCall);
    m_jitCodeForCall = m_codeBlockForCall->getJITCode();
    m_jitCodeForCallWithArityCheck = m_codeBlockForCall->getJITCodeWithArityCheck();
}

void FunctionExecutable::jettisonOptimizedCodeForConstruct(JSGlobalData& globalData)
{
    jettisonCodeBlock(globalData, m_codeBlockForConstruct);
    m_jitCodeForConstruct = m_codeBlockForConstruct->getJITCode();
    m_jitCodeForConstructWithArityCheck = m_codeBlockForConstruct->getJITCodeWithArityCheck();
}
#endif

void FunctionExecutable::visitChildren(JSCell* cell, SlotVisitor& visitor)
{
    FunctionExecutable* thisObject = jsCast<FunctionExecutable*>(cell);
    ASSERT_GC_OBJECT_INHERITS(thisObject, &s_info);
    COMPILE_ASSERT(StructureFlags & OverridesVisitChildren, OverridesVisitChildrenWithoutSettingFlag);
    ASSERT(thisObject->structure()->typeInfo().overridesVisitChildren());
    ScriptExecutable::visitChildren(thisObject, visitor);
    if (thisObject->m_codeBlockForCall)
        thisObject->m_codeBlockForCall->visitAggregate(visitor);
    if (thisObject->m_codeBlockForConstruct)
        thisObject->m_codeBlockForConstruct->visitAggregate(visitor);
    visitor.append(&thisObject->m_unlinkedExecutable);
}

void FunctionExecutable::clearCodeIfNotCompiling()
{
    if (isCompiling())
        return;
    clearCode();
}

void FunctionExecutable::clearUnlinkedCodeForRecompilationIfNotCompiling()
{
    if (isCompiling())
        return;
    m_unlinkedExecutable->clearCodeForRecompilation();
}

void FunctionExecutable::clearCode()
{
    m_codeBlockForCall.clear();
    m_codeBlockForConstruct.clear();
    Base::clearCode();
}

void FunctionExecutable::unlinkCalls()
{
#if ENABLE(JIT)
    if (!!m_jitCodeForCall) {
        ASSERT(m_codeBlockForCall);
        m_codeBlockForCall->unlinkCalls();
    }
    if (!!m_jitCodeForConstruct) {
        ASSERT(m_codeBlockForConstruct);
        m_codeBlockForConstruct->unlinkCalls();
    }
#endif
}

FunctionExecutable* FunctionExecutable::fromGlobalCode(const Identifier& name, ExecState* exec, Debugger* debugger, const SourceCode& source, JSObject** exception)
{
    UnlinkedFunctionExecutable* unlinkedFunction = UnlinkedFunctionExecutable::fromGlobalCode(name, exec, debugger, source, exception);
    if (!unlinkedFunction)
        return 0;
    unsigned firstLine = source.firstLine() + unlinkedFunction->firstLineOffset();
    unsigned startOffset = source.startOffset() + unlinkedFunction->startOffset();
    unsigned sourceLength = unlinkedFunction->sourceLength();
    SourceCode functionSource(source.provider(), startOffset, startOffset + sourceLength, firstLine);
    return FunctionExecutable::create(exec->globalData(), functionSource, unlinkedFunction, firstLine, unlinkedFunction->lineCount());
}

String FunctionExecutable::paramString() const
{
    return m_unlinkedExecutable->paramString();
}

CodeBlockHash ExecutableBase::hashFor(CodeSpecializationKind kind) const
{
    if (this->classInfo() == NativeExecutable::s_classinfo())
        return jsCast<const NativeExecutable*>(this)->hashFor(kind);
    
    return jsCast<const ScriptExecutable*>(this)->hashFor(kind);
}

CodeBlockHash NativeExecutable::hashFor(CodeSpecializationKind kind) const
{
    if (kind == CodeForCall)
        return CodeBlockHash(static_cast<unsigned>(bitwise_cast<size_t>(m_function)));
    
    ASSERT(kind == CodeForConstruct);
    return CodeBlockHash(static_cast<unsigned>(bitwise_cast<size_t>(m_constructor)));
}

CodeBlockHash ScriptExecutable::hashFor(CodeSpecializationKind kind) const
{
    return CodeBlockHash(source(), kind);
}

}