JSObject* ProgramExecutable::initializeGlobalProperties(VM& vm, CallFrame* callFrame, JSScope* scope)
{
    RELEASE_ASSERT(scope);
    JSGlobalObject* globalObject = scope->globalObject();
    RELEASE_ASSERT(globalObject);
    ASSERT(&globalObject->vm() == &vm);

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

    m_unlinkedProgramCodeBlock.set(vm, this, unlinkedCodeBlock);

    BatchedTransitionOptimizer optimizer(vm, globalObject);

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

    for (size_t i = 0; i < functionDeclarations.size(); ++i) {
        UnlinkedFunctionExecutable* unlinkedFunctionExecutable = functionDeclarations[i].second.get();
        JSValue value = JSFunction::create(vm, unlinkedFunctionExecutable->link(vm, m_source, lineNo(), 0), scope);
        globalObject->addFunction(callFrame, functionDeclarations[i].first, value);
    }

    for (size_t i = 0; i < variableDeclarations.size(); ++i) {
        if (variableDeclarations[i].second & DeclarationStacks::IsConstant)
            globalObject->addConst(callFrame, variableDeclarations[i].first);
        else
            globalObject->addVar(callFrame, variableDeclarations[i].first);
    }
    return 0;
}

JSObject* ProgramExecutable::initializeGlobalProperties(VM& vm, CallFrame* callFrame, JSScope* scope)
{
    RELEASE_ASSERT(scope);
    JSGlobalObject* globalObject = scope->globalObject();
    RELEASE_ASSERT(globalObject);
    ASSERT(&globalObject->vm() == &vm);

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

    m_unlinkedProgramCodeBlock.set(vm, this, unlinkedCodeBlock);

    BatchedTransitionOptimizer optimizer(vm, globalObject);

    for (size_t i = 0, numberOfFunctions = unlinkedCodeBlock->numberOfFunctionDecls(); i < numberOfFunctions; ++i) {
        UnlinkedFunctionExecutable* unlinkedFunctionExecutable = unlinkedCodeBlock->functionDecl(i);
        ASSERT(!unlinkedFunctionExecutable->name().isEmpty());
        globalObject->addFunction(callFrame, unlinkedFunctionExecutable->name());
        if (vm.typeProfiler() || vm.controlFlowProfiler()) {
            vm.functionHasExecutedCache()->insertUnexecutedRange(sourceID(), 
                unlinkedFunctionExecutable->typeProfilingStartOffset(), 
                unlinkedFunctionExecutable->typeProfilingEndOffset());
        }
    }

    const VariableEnvironment& variableDeclarations = unlinkedCodeBlock->variableDeclarations();
    for (auto& entry : variableDeclarations) {
        ASSERT(entry.value.isVar());
        globalObject->addVar(callFrame, Identifier::fromUid(&vm, entry.key.get()));
    }
    return 0;
}

void UnlinkedFunctionExecutable::visitChildren(JSCell* cell, SlotVisitor& visitor)
{
    UnlinkedFunctionExecutable* thisObject = jsCast<UnlinkedFunctionExecutable*>(cell);
    ASSERT_GC_OBJECT_INHERITS(thisObject, &s_info);
    COMPILE_ASSERT(StructureFlags & OverridesVisitChildren, OverridesVisitChildrenWithoutSettingFlag);
    ASSERT(thisObject->structure()->typeInfo().overridesVisitChildren());
    Base::visitChildren(thisObject, visitor);
    visitor.append(&thisObject->m_nameValue);
    visitor.append(&thisObject->m_symbolTableForCall);
    visitor.append(&thisObject->m_symbolTableForConstruct);
}

FunctionExecutable* FunctionExecutable::fromGlobalCode(
    const Identifier& name, ExecState& exec, const SourceCode& source, 
    JSObject*& exception, int overrideLineNumber)
{
    UnlinkedFunctionExecutable* unlinkedExecutable = 
        UnlinkedFunctionExecutable::fromGlobalCode(
            name, exec, source, exception, overrideLineNumber);
    if (!unlinkedExecutable)
        return nullptr;

    return unlinkedExecutable->link(exec.vm(), source, overrideLineNumber);
}

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

    // We don't have any owner executable. The source string is effectively like a global
    // string (like in the handling of eval). Hence, the startColumn is always 1.
    unsigned startColumn = 1;
    unsigned sourceLength = unlinkedExecutable->sourceLength();
    bool endColumnIsOnStartLine = !lineCount;
    // The unlinkedBodyEndColumn is based-0. Hence, we need to add 1 to it. But if the
    // endColumn is on the startLine, then we need to subtract back the adjustment for
    // the open brace resulting in an adjustment of 0.
    unsigned endColumnExcludingBraces = unlinkedExecutable->unlinkedBodyEndColumn() + (endColumnIsOnStartLine ? 0 : 1);
    unsigned startOffsetExcludingOpenBrace = startOffset + 1;
    unsigned endOffsetExcludingCloseBrace = startOffset + sourceLength - 1;
#if ENABLE(VMOLAB)
    SourceCode bodySource(source.provider(), startOffset, startOffset + sourceLength, firstLine, startColumn);
    return FunctionExecutable::create(exec->vm(), bodySource, unlinkedExecutable, firstLine, firstLine + lineCount, startColumn, endColumnExcludingBraces);
#else
    SourceCode bodySource(source.provider(), startOffsetExcludingOpenBrace, endOffsetExcludingCloseBrace, firstLine, startColumn);
    return FunctionExecutable::create(exec->vm(), bodySource, unlinkedExecutable, firstLine, firstLine + lineCount, startColumn, endColumnExcludingBraces, false);
#endif

}

// FIXME: There's no need to add the function's name to the key here. It's already in the source code.
UnlinkedFunctionExecutable* CodeCache::getFunctionExecutableFromGlobalCode(VM& vm, const Identifier& name, const SourceCode& source, ParserError& error)
{
    bool isArrowFunctionContext = false;
    SourceCodeKey key(
        source, name.string(), SourceCodeType::FunctionType,
        JSParserBuiltinMode::NotBuiltin,
        JSParserStrictMode::NotStrict,
        JSParserCommentMode::Classic,
        DerivedContextType::None,
        EvalContextType::None,
        isArrowFunctionContext);
    SourceCodeValue* cache = m_sourceCode.findCacheAndUpdateAge(key);
    if (cache) {
        UnlinkedFunctionExecutable* executable = jsCast<UnlinkedFunctionExecutable*>(cache->cell.get());
        source.provider()->setSourceURLDirective(executable->sourceURLDirective());
        source.provider()->setSourceMappingURLDirective(executable->sourceMappingURLDirective());
        return executable;
    }

    JSTextPosition positionBeforeLastNewline;
    std::unique_ptr<ProgramNode> program = parse<ProgramNode>(
        &vm, source, Identifier(), JSParserBuiltinMode::NotBuiltin,
        JSParserStrictMode::NotStrict, JSParserCommentMode::Classic, SourceParseMode::ProgramMode, SuperBinding::NotNeeded,
        error, &positionBeforeLastNewline);
    if (!program) {
        RELEASE_ASSERT(error.isValid());
        return nullptr;
    }

    // This function assumes an input string that would result in a single function declaration.
    StatementNode* statement = program->singleStatement();
    ASSERT(statement);
    ASSERT(statement->isBlock());
    if (!statement || !statement->isBlock())
        return nullptr;

    StatementNode* funcDecl = static_cast<BlockNode*>(statement)->singleStatement();
    ASSERT(funcDecl);
    ASSERT(funcDecl->isFuncDeclNode());
    if (!funcDecl || !funcDecl->isFuncDeclNode())
        return nullptr;

    FunctionMetadataNode* metadata = static_cast<FuncDeclNode*>(funcDecl)->metadata();
    ASSERT(metadata);
    if (!metadata)
        return nullptr;
    
    metadata->overrideName(name);
    metadata->setEndPosition(positionBeforeLastNewline);
    // The Function constructor only has access to global variables, so no variables will be under TDZ.
    VariableEnvironment emptyTDZVariables;
    UnlinkedFunctionExecutable* functionExecutable = UnlinkedFunctionExecutable::create(&vm, source, metadata, UnlinkedNormalFunction, ConstructAbility::CanConstruct, JSParserCommentMode::Classic, emptyTDZVariables, DerivedContextType::None);

    functionExecutable->setSourceURLDirective(source.provider()->sourceURL());
    functionExecutable->setSourceMappingURLDirective(source.provider()->sourceMappingURL());

    m_sourceCode.addCache(key, SourceCodeValue(vm, functionExecutable, m_sourceCode.age()));
    return functionExecutable;
}

JSObject* ProgramExecutable::initializeGlobalProperties(VM& vm, CallFrame* callFrame, JSScope* scope)
{
    auto throwScope = DECLARE_THROW_SCOPE(vm);
    RELEASE_ASSERT(scope);
    JSGlobalObject* globalObject = scope->globalObject();
    RELEASE_ASSERT(globalObject);
    ASSERT(&globalObject->vm() == &vm);

    ParserError error;
    JSParserStrictMode strictMode = isStrictMode() ? JSParserStrictMode::Strict : JSParserStrictMode::NotStrict;
    DebuggerMode debuggerMode = globalObject->hasInteractiveDebugger() ? DebuggerOn : DebuggerOff;

    UnlinkedProgramCodeBlock* unlinkedCodeBlock = vm.codeCache()->getUnlinkedProgramCodeBlock(
        vm, this, source(), strictMode, debuggerMode, error);

    if (globalObject->hasDebugger())
        globalObject->debugger()->sourceParsed(callFrame, source().provider(), error.line(), error.message());

    if (error.isValid())
        return error.toErrorObject(globalObject, source());

    JSValue nextPrototype = globalObject->getPrototypeDirect();
    while (nextPrototype && nextPrototype.isObject()) {
        if (UNLIKELY(asObject(nextPrototype)->type() == ProxyObjectType)) {
            ExecState* exec = globalObject->globalExec();
            return createTypeError(exec, ASCIILiteral("Proxy is not allowed in the global prototype chain."));
        }
        nextPrototype = asObject(nextPrototype)->getPrototypeDirect();
    }
    
    JSGlobalLexicalEnvironment* globalLexicalEnvironment = globalObject->globalLexicalEnvironment();
    const VariableEnvironment& variableDeclarations = unlinkedCodeBlock->variableDeclarations();
    const VariableEnvironment& lexicalDeclarations = unlinkedCodeBlock->lexicalDeclarations();
    // The ES6 spec says that no vars/global properties/let/const can be duplicated in the global scope.
    // This carried out section 15.1.8 of the ES6 spec: http://www.ecma-international.org/ecma-262/6.0/index.html#sec-globaldeclarationinstantiation
    {
        ExecState* exec = globalObject->globalExec();
        // Check for intersection of "var" and "let"/"const"/"class"
        for (auto& entry : lexicalDeclarations) {
            if (variableDeclarations.contains(entry.key))
                return createSyntaxError(exec, makeString("Can't create duplicate variable: '", String(entry.key.get()), "'"));
        }

        // Check if any new "let"/"const"/"class" will shadow any pre-existing global property names, or "var"/"let"/"const" variables.
        // It's an error to introduce a shadow.
        for (auto& entry : lexicalDeclarations) {
            bool hasProperty = globalObject->hasProperty(exec, entry.key.get());
            RETURN_IF_EXCEPTION(throwScope, throwScope.exception());
            if (hasProperty) {
                // The ES6 spec says that just RestrictedGlobalProperty can't be shadowed
                // This carried out section 8.1.1.4.14 of the ES6 spec: http://www.ecma-international.org/ecma-262/6.0/index.html#sec-hasrestrictedglobalproperty
                PropertyDescriptor descriptor;
                globalObject->getOwnPropertyDescriptor(exec, entry.key.get(), descriptor);
                
                if (descriptor.value() != jsUndefined() && !descriptor.configurable())
                    return createSyntaxError(exec, makeString("Can't create duplicate variable that shadows a global property: '", String(entry.key.get()), "'"));
            }

            hasProperty = globalLexicalEnvironment->hasProperty(exec, entry.key.get());
            RETURN_IF_EXCEPTION(throwScope, throwScope.exception());
            if (hasProperty) {
                if (UNLIKELY(entry.value.isConst() && !vm.globalConstRedeclarationShouldThrow() && !isStrictMode())) {
                    // We only allow "const" duplicate declarations under this setting.
                    // For example, we don't "let" variables to be overridden by "const" variables.
                    if (globalLexicalEnvironment->isConstVariable(entry.key.get()))
                        continue;
                }
                return createSyntaxError(exec, makeString("Can't create duplicate variable: '", String(entry.key.get()), "'"));
            }
        }

        // Check if any new "var"s will shadow any previous "let"/"const"/"class" names.
        // It's an error to introduce a shadow.
        if (!globalLexicalEnvironment->isEmpty()) {
            for (auto& entry : variableDeclarations) {
                bool hasProperty = globalLexicalEnvironment->hasProperty(exec, entry.key.get());
                RETURN_IF_EXCEPTION(throwScope, throwScope.exception());
                if (hasProperty)
                    return createSyntaxError(exec, makeString("Can't create duplicate variable: '", String(entry.key.get()), "'"));
            }
        }
    }


    m_unlinkedProgramCodeBlock.set(vm, this, unlinkedCodeBlock);

    BatchedTransitionOptimizer optimizer(vm, globalObject);

    for (size_t i = 0, numberOfFunctions = unlinkedCodeBlock->numberOfFunctionDecls(); i < numberOfFunctions; ++i) {
        UnlinkedFunctionExecutable* unlinkedFunctionExecutable = unlinkedCodeBlock->functionDecl(i);
        ASSERT(!unlinkedFunctionExecutable->name().isEmpty());
        globalObject->addFunction(callFrame, unlinkedFunctionExecutable->name());
        if (vm.typeProfiler() || vm.controlFlowProfiler()) {
            vm.functionHasExecutedCache()->insertUnexecutedRange(sourceID(), 
                unlinkedFunctionExecutable->typeProfilingStartOffset(), 
                unlinkedFunctionExecutable->typeProfilingEndOffset());
        }
    }

    for (auto& entry : variableDeclarations) {
//.........这里部分代码省略.........

JSObject* ProgramExecutable::initializeGlobalProperties(VM& vm, CallFrame* callFrame, JSScope* scope)
{
    RELEASE_ASSERT(scope);
    JSGlobalObject* globalObject = scope->globalObject();
    RELEASE_ASSERT(globalObject);
    ASSERT(&globalObject->vm() == &vm);

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

    JSGlobalLexicalEnvironment* globalLexicalEnvironment = globalObject->globalLexicalEnvironment();
    const VariableEnvironment& variableDeclarations = unlinkedCodeBlock->variableDeclarations();
    const VariableEnvironment& lexicalDeclarations = unlinkedCodeBlock->lexicalDeclarations();
    // The ES6 spec says that no vars/global properties/let/const can be duplicated in the global scope.
    // This carried out section 15.1.8 of the ES6 spec: http://www.ecma-international.org/ecma-262/6.0/index.html#sec-globaldeclarationinstantiation
    {
        ExecState* exec = globalObject->globalExec();
        // Check for intersection of "var" and "let"/"const"/"class"
        for (auto& entry : lexicalDeclarations) {
            if (variableDeclarations.contains(entry.key))
                return createSyntaxError(exec, makeString("Can't create duplicate variable: '", String(entry.key.get()), "'"));
        }

        // Check if any new "let"/"const"/"class" will shadow any pre-existing global property names, or "var"/"let"/"const" variables.
        // It's an error to introduce a shadow.
        for (auto& entry : lexicalDeclarations) {
            if (globalObject->hasProperty(exec, entry.key.get()))
                return createSyntaxError(exec, makeString("Can't create duplicate variable that shadows a global property: '", String(entry.key.get()), "'"));

            if (globalLexicalEnvironment->hasProperty(exec, entry.key.get()))
                return createSyntaxError(exec, makeString("Can't create duplicate variable: '", String(entry.key.get()), "'"));
        }

        // Check if any new "var"s will shadow any previous "let"/"const"/"class" names.
        // It's an error to introduce a shadow.
        if (!globalLexicalEnvironment->isEmpty()) {
            for (auto& entry : variableDeclarations) {
                if (globalLexicalEnvironment->hasProperty(exec, entry.key.get()))
                    return createSyntaxError(exec, makeString("Can't create duplicate variable: '", String(entry.key.get()), "'"));
            }
        }
    }


    m_unlinkedProgramCodeBlock.set(vm, this, unlinkedCodeBlock);

    BatchedTransitionOptimizer optimizer(vm, globalObject);

    for (size_t i = 0, numberOfFunctions = unlinkedCodeBlock->numberOfFunctionDecls(); i < numberOfFunctions; ++i) {
        UnlinkedFunctionExecutable* unlinkedFunctionExecutable = unlinkedCodeBlock->functionDecl(i);
        ASSERT(!unlinkedFunctionExecutable->name().isEmpty());
        globalObject->addFunction(callFrame, unlinkedFunctionExecutable->name());
        if (vm.typeProfiler() || vm.controlFlowProfiler()) {
            vm.functionHasExecutedCache()->insertUnexecutedRange(sourceID(), 
                unlinkedFunctionExecutable->typeProfilingStartOffset(), 
                unlinkedFunctionExecutable->typeProfilingEndOffset());
        }
    }

    for (auto& entry : variableDeclarations) {
        ASSERT(entry.value.isVar());
        globalObject->addVar(callFrame, Identifier::fromUid(&vm, entry.key.get()));
    }

    {
        JSGlobalLexicalEnvironment* globalLexicalEnvironment = jsCast<JSGlobalLexicalEnvironment*>(globalObject->globalScope());
        SymbolTable* symbolTable = globalLexicalEnvironment->symbolTable();
        ConcurrentJITLocker locker(symbolTable->m_lock);
        for (auto& entry : lexicalDeclarations) {
            ScopeOffset offset = symbolTable->takeNextScopeOffset(locker);
            SymbolTableEntry newEntry(VarOffset(offset), entry.value.isConst() ? ReadOnly : 0);
            newEntry.prepareToWatch();
            symbolTable->add(locker, entry.key.get(), newEntry);
            
            ScopeOffset offsetForAssert = globalLexicalEnvironment->addVariables(1, jsTDZValue());
            RELEASE_ASSERT(offsetForAssert == offset);
        }
    }
    return 0;
}