C++ SymbolTableEntry::varOffset方法代码示例

void JSModuleRecord::instantiateDeclarations(ExecState* exec, ModuleProgramExecutable* moduleProgramExecutable)
{
    VM& vm = exec->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);

    // http://www.ecma-international.org/ecma-262/6.0/#sec-moduledeclarationinstantiation

    SymbolTable* symbolTable = moduleProgramExecutable->moduleEnvironmentSymbolTable();
    JSModuleEnvironment* moduleEnvironment = JSModuleEnvironment::create(vm, exec->lexicalGlobalObject(), exec->lexicalGlobalObject(), symbolTable, jsTDZValue(), this);

    // http://www.ecma-international.org/ecma-262/6.0/#sec-moduledeclarationinstantiation
    // section 15.2.1.16.4 step 9.
    // Ensure all the indirect exports are correctly resolved to unique bindings.
    // Even if we avoided duplicate exports in the parser, still ambiguous exports occur due to the star export (`export * from "mod"`).
    // When we see this type of ambiguity for the indirect exports here, throw a syntax error.
    for (const auto& pair : exportEntries()) {
        const ExportEntry& exportEntry = pair.value;
        if (exportEntry.type == JSModuleRecord::ExportEntry::Type::Indirect) {
            Resolution resolution = resolveExport(exec, exportEntry.exportName);
            switch (resolution.type) {
            case Resolution::Type::NotFound:
                throwSyntaxError(exec, scope, makeString("Indirectly exported binding name '", String(exportEntry.exportName.impl()), "' is not found."));
                return;

            case Resolution::Type::Ambiguous:
                throwSyntaxError(exec, scope, makeString("Indirectly exported binding name '", String(exportEntry.exportName.impl()), "' cannot be resolved due to ambiguous multiple bindings."));
                return;

            case Resolution::Type::Error:
                throwSyntaxError(exec, scope, makeString("Indirectly exported binding name 'default' cannot be resolved by star export entries."));
                return;

            case Resolution::Type::Resolved:
                break;
            }
        }
    }

    // http://www.ecma-international.org/ecma-262/6.0/#sec-moduledeclarationinstantiation
    // section 15.2.1.16.4 step 12.
    // Instantiate namespace objects and initialize the bindings with them if required.
    // And ensure that all the imports correctly resolved to unique bindings.
    for (const auto& pair : importEntries()) {
        const ImportEntry& importEntry = pair.value;
        AbstractModuleRecord* importedModule = hostResolveImportedModule(exec, importEntry.moduleRequest);
        if (importEntry.isNamespace(vm)) {
            JSModuleNamespaceObject* namespaceObject = importedModule->getModuleNamespace(exec);
            RETURN_IF_EXCEPTION(scope, void());
            bool putResult = false;
            symbolTablePutTouchWatchpointSet(moduleEnvironment, exec, importEntry.localName, namespaceObject, /* shouldThrowReadOnlyError */ false, /* ignoreReadOnlyErrors */ true, putResult);
        } else {
            Resolution resolution = importedModule->resolveExport(exec, importEntry.importName);
            switch (resolution.type) {
            case Resolution::Type::NotFound:
                throwSyntaxError(exec, scope, makeString("Importing binding name '", String(importEntry.importName.impl()), "' is not found."));
                return;

            case Resolution::Type::Ambiguous:
                throwSyntaxError(exec, scope, makeString("Importing binding name '", String(importEntry.importName.impl()), "' cannot be resolved due to ambiguous multiple bindings."));
                return;

            case Resolution::Type::Error:
                throwSyntaxError(exec, scope, makeString("Importing binding name 'default' cannot be resolved by star export entries."));
                return;

            case Resolution::Type::Resolved:
                break;
            }
        }
    }

    // http://www.ecma-international.org/ecma-262/6.0/#sec-moduledeclarationinstantiation
    // section 15.2.1.16.4 step 14.
    // Module environment contains the heap allocated "var", "function", "let", "const", and "class".
    // When creating the environment, we initialized all the slots with empty, it's ok for lexical values.
    // But for "var" and "function", we should initialize it with undefined. They are contained in the declared variables.
    for (const auto& variable : declaredVariables()) {
        SymbolTableEntry entry = symbolTable->get(variable.key.get());
        VarOffset offset = entry.varOffset();
        if (!offset.isStack()) {
            bool putResult = false;
            symbolTablePutTouchWatchpointSet(moduleEnvironment, exec, Identifier::fromUid(exec, variable.key.get()), jsUndefined(), /* shouldThrowReadOnlyError */ false, /* ignoreReadOnlyErrors */ true, putResult);
        }
    }

    // http://www.ecma-international.org/ecma-262/6.0/#sec-moduledeclarationinstantiation
    // section 15.2.1.16.4 step 16-a-iv.
    // Initialize heap allocated function declarations.
    // They can be called before the body of the module is executed under circular dependencies.
    UnlinkedModuleProgramCodeBlock* unlinkedCodeBlock = moduleProgramExecutable->unlinkedModuleProgramCodeBlock();
    for (size_t i = 0, numberOfFunctions = unlinkedCodeBlock->numberOfFunctionDecls(); i < numberOfFunctions; ++i) {
        UnlinkedFunctionExecutable* unlinkedFunctionExecutable = unlinkedCodeBlock->functionDecl(i);
        SymbolTableEntry entry = symbolTable->get(unlinkedFunctionExecutable->name().impl());
        VarOffset offset = entry.varOffset();
        if (!offset.isStack()) {
            ASSERT(!unlinkedFunctionExecutable->name().isEmpty());
            if (vm.typeProfiler() || vm.controlFlowProfiler()) {
                vm.functionHasExecutedCache()->insertUnexecutedRange(moduleProgramExecutable->sourceID(),
                    unlinkedFunctionExecutable->typeProfilingStartOffset(),
                    unlinkedFunctionExecutable->typeProfilingEndOffset());
//.........这里部分代码省略.........