C++ CallFrame::codeBlock方法代码示例

bool JSActivation::getOwnPropertySlot(JSObject* object, ExecState* exec, PropertyName propertyName, PropertySlot& slot)
{
    JSActivation* thisObject = jsCast<JSActivation*>(object);

    if (propertyName == exec->propertyNames().arguments) {
        // Defend against the inspector asking for the arguments object after it has been optimized out.
        CallFrame* callFrame = CallFrame::create(reinterpret_cast<Register*>(thisObject->m_registers));
        if (!thisObject->isTornOff() && (callFrame->codeBlock()->usesArguments() || callFrame->codeBlock()->usesEval())) {
            slot.setCustom(thisObject, DontEnum, argumentsGetter);
            return true;
        }
    }

    if (thisObject->symbolTableGet(propertyName, slot))
        return true;

    unsigned attributes;
    if (JSValue value = thisObject->getDirect(exec->vm(), propertyName, attributes)) {
        slot.setValue(thisObject, attributes, value);
        return true;
    }

    // We don't call through to JSObject because there's no way to give an 
    // activation object getter properties or a prototype.
    ASSERT(!thisObject->hasGetterSetterProperties());
    ASSERT(thisObject->prototype().isNull());
    return false;
}

// Evaluate some JavaScript code in the scope of this frame.
JSValue DebuggerCallFrame::evaluate(const String& script, JSValue& exception)
{
    ASSERT(isValid());
    CallFrame* callFrame = m_callFrame;
    if (!callFrame)
        return jsNull();

    JSLockHolder lock(callFrame);

    if (!callFrame->codeBlock())
        return JSValue();
    
    VM& vm = callFrame->vm();
    EvalExecutable* eval = EvalExecutable::create(callFrame, makeSource(script), callFrame->codeBlock()->isStrictMode());
    if (vm.exception()) {
        exception = vm.exception();
        vm.clearException();
        return jsUndefined();
    }

    JSValue thisValue = thisValueForCallFrame(callFrame);
    JSValue result = vm.interpreter->execute(eval, callFrame, thisValue, scope());
    if (vm.exception()) {
        exception = vm.exception();
        vm.clearException();
    }
    ASSERT(result);
    return result;
}

JSValue DebuggerCallFrame::evaluateNonBlocking(const String& script, NakedPtr<Exception>& exception)
{
	ASSERT(isValid());
	CallFrame* callFrame = m_callFrame;
	if (!callFrame)
		return jsNull();

	if (!callFrame->codeBlock())
		return JSValue();

	DebuggerEvalEnabler evalEnabler(callFrame);
	VM& vm = callFrame->vm();
	auto& codeBlock = *callFrame->codeBlock();
	ThisTDZMode thisTDZMode = codeBlock.unlinkedCodeBlock()->constructorKind() == ConstructorKind::Derived ? ThisTDZMode::AlwaysCheck : ThisTDZMode::CheckIfNeeded;

	VariableEnvironment variablesUnderTDZ;
	JSScope::collectVariablesUnderTDZ(scope()->jsScope(), variablesUnderTDZ);

	EvalExecutable* eval = EvalExecutable::create(callFrame, makeSource(script), codeBlock.isStrictMode(), thisTDZMode, codeBlock.unlinkedCodeBlock()->isDerivedConstructorContext(), codeBlock.unlinkedCodeBlock()->isArrowFunction(), &variablesUnderTDZ);
	if (vm.exception()) {
		exception = vm.exception();
		vm.clearException();
		return jsUndefined();
	}

	JSValue thisValue = thisValueForCallFrame(callFrame);
	JSValue result = vm.interpreter->execute(eval, callFrame, thisValue, scope()->jsScope());
	if (vm.exception()) {
		exception = vm.exception();
		vm.clearException();
	}
	ASSERT(result);
	return result;
}

CallFrame* CallFrame::trueCallerFrameSlow()
{
    // this -> The callee; this is either an inlined callee in which case it already has
    //    a pointer to the true caller. Otherwise it contains current PC in the machine
    //    caller.
    //
    // machineCaller -> The caller according to the machine, which may be zero or
    //    more frames above the true caller due to inlining.
    //
    // trueCaller -> The real caller.
    
    // Am I an inline call frame? If so, we're done.
    if (isInlineCallFrame())
        return callerFrame();
    
    // I am a machine call frame, so the question is: is my caller a machine call frame
    // that has inlines or a machine call frame that doesn't?
    CallFrame* machineCaller = callerFrame()->removeHostCallFrameFlag();
    if (!machineCaller)
        return 0;
    ASSERT(!machineCaller->isInlineCallFrame());
    if (!machineCaller->codeBlock() || !machineCaller->codeBlock()->hasCodeOrigins())
        return machineCaller; // No inlining, so machineCaller == trueCaller
    
    // Figure out where the caller frame would have gone relative to the machine
    // caller, and rematerialize it. Do so for the entire inline stack.
    
    CodeOrigin codeOrigin = machineCaller->codeBlock()->codeOriginForReturn(returnPC());
    
    for (InlineCallFrame* inlineCallFrame = codeOrigin.inlineCallFrame; inlineCallFrame;) {
        InlineCallFrame* nextInlineCallFrame = inlineCallFrame = inlineCallFrame->caller.inlineCallFrame;
        
        CallFrame* inlinedCaller = machineCaller + inlineCallFrame->stackOffset;
        
        JSObject* callee = machineCaller->registers()[inlineCallFrame->calleeVR].function();
        JSCell* calleeAsFunctionCell = getJSFunction(callee);
        ASSERT(calleeAsFunctionCell);
        JSFunction* calleeAsFunction = asFunction(calleeAsFunctionCell);
        
        // Fill in the inlinedCaller
        inlinedCaller->setCodeBlock(machineCaller->codeBlock());
        
        inlinedCaller->setScopeChain(calleeAsFunction->scope());
        if (nextInlineCallFrame)
            inlinedCaller->setCallerFrame(machineCaller + nextInlineCallFrame->stackOffset);
        else
            inlinedCaller->setCallerFrame(machineCaller);
        
        inlinedCaller->setInlineCallFrame(inlineCallFrame);
        inlinedCaller->setArgumentCountIncludingThis(inlineCallFrame->numArgumentsIncludingThis);
        inlinedCaller->setCallee(callee);
        
        inlineCallFrame = nextInlineCallFrame;
    }
    
    return machineCaller + codeOrigin.inlineCallFrame->stackOffset;
}

// Evaluate some JavaScript code in the scope of this frame.
JSValue DebuggerCallFrame::evaluateWithScopeExtension(const String& script, JSObject* scopeExtensionObject, NakedPtr<Exception>& exception)
{
    ASSERT(isValid());
    CallFrame* callFrame = m_validMachineFrame;
    if (!callFrame)
        return jsUndefined();

    VM& vm = callFrame->vm();
    JSLockHolder lock(vm);
    auto catchScope = DECLARE_CATCH_SCOPE(vm);

    CodeBlock* codeBlock = nullptr;
    if (isTailDeleted())
        codeBlock = m_shadowChickenFrame.codeBlock;
    else
        codeBlock = callFrame->codeBlock();
    if (!codeBlock)
        return jsUndefined();
    
    DebuggerEvalEnabler evalEnabler(callFrame);

    EvalContextType evalContextType;
    
    if (isFunctionParseMode(codeBlock->unlinkedCodeBlock()->parseMode()))
        evalContextType = EvalContextType::FunctionEvalContext;
    else if (codeBlock->unlinkedCodeBlock()->codeType() == EvalCode)
        evalContextType = codeBlock->unlinkedCodeBlock()->evalContextType();
    else 
        evalContextType = EvalContextType::None;

    VariableEnvironment variablesUnderTDZ;
    JSScope::collectClosureVariablesUnderTDZ(scope()->jsScope(), variablesUnderTDZ);

    EvalExecutable* eval = DirectEvalExecutable::create(callFrame, makeSource(script), codeBlock->isStrictMode(), codeBlock->unlinkedCodeBlock()->derivedContextType(), codeBlock->unlinkedCodeBlock()->isArrowFunction(), evalContextType, &variablesUnderTDZ);
    if (UNLIKELY(catchScope.exception())) {
        exception = catchScope.exception();
        catchScope.clearException();
        return jsUndefined();
    }

    JSGlobalObject* globalObject = callFrame->vmEntryGlobalObject();
    if (scopeExtensionObject) {
        JSScope* ignoredPreviousScope = globalObject->globalScope();
        globalObject->setGlobalScopeExtension(JSWithScope::create(vm, globalObject, scopeExtensionObject, ignoredPreviousScope));
    }

    JSValue thisValue = this->thisValue();
    JSValue result = vm.interpreter->execute(eval, callFrame, thisValue, scope()->jsScope());
    if (UNLIKELY(catchScope.exception())) {
        exception = catchScope.exception();
        catchScope.clearException();
    }

    if (scopeExtensionObject)
        globalObject->clearGlobalScopeExtension();

    ASSERT(result);
    return result;
}

EncodedJSValue JSActivation::argumentsGetter(ExecState*, EncodedJSValue slotBase, EncodedJSValue, PropertyName)
{
    JSActivation* activation = jsCast<JSActivation*>(JSValue::decode(slotBase));
    CallFrame* callFrame = CallFrame::create(reinterpret_cast<Register*>(activation->m_registers));
    ASSERT(!activation->isTornOff() && (callFrame->codeBlock()->usesArguments() || callFrame->codeBlock()->usesEval()));
    if (activation->isTornOff() || !(callFrame->codeBlock()->usesArguments() || callFrame->codeBlock()->usesEval()))
        return JSValue::encode(jsUndefined());

    VirtualRegister argumentsRegister = callFrame->codeBlock()->argumentsRegister();
    if (JSValue arguments = callFrame->uncheckedR(argumentsRegister.offset()).jsValue())
        return JSValue::encode(arguments);
    int realArgumentsRegister = unmodifiedArgumentsRegister(argumentsRegister).offset();

    JSValue arguments = JSValue(Arguments::create(callFrame->vm(), callFrame));
    callFrame->uncheckedR(argumentsRegister.offset()) = arguments;
    callFrame->uncheckedR(realArgumentsRegister) = arguments;
    
    ASSERT(callFrame->uncheckedR(realArgumentsRegister).jsValue().inherits(Arguments::info()));
    return JSValue::encode(callFrame->uncheckedR(realArgumentsRegister).jsValue());
}

void ErrorInstance::finishCreation(ExecState* exec, VM& vm, const String& message, bool useCurrentFrame)
{
    Base::finishCreation(vm);
    ASSERT(inherits(info()));
    if (!message.isNull())
        putDirect(vm, vm.propertyNames->message, jsString(&vm, message), DontEnum);

    unsigned bytecodeOffset = hasSourceAppender();
    CallFrame* callFrame = nullptr;
    bool hasTrace = addErrorInfoAndGetBytecodeOffset(exec, vm, this, useCurrentFrame, callFrame, bytecodeOffset);

    if (hasTrace && callFrame && hasSourceAppender()) {
        if (callFrame && callFrame->codeBlock()) 
            appendSourceToError(callFrame, this, bytecodeOffset);
    }
}

EncodedJSValue JSLexicalEnvironment::argumentsGetter(ExecState*, JSObject* slotBase, EncodedJSValue, PropertyName)
{
    JSLexicalEnvironment* lexicalEnvironment = jsCast<JSLexicalEnvironment*>(slotBase);
    CallFrame* callFrame = CallFrame::create(reinterpret_cast<Register*>(lexicalEnvironment->m_registers));
    return JSValue::encode(jsUndefined());

    VirtualRegister argumentsRegister = callFrame->codeBlock()->argumentsRegister();
    if (JSValue arguments = callFrame->uncheckedR(argumentsRegister.offset()).jsValue())
        return JSValue::encode(arguments);
    int realArgumentsRegister = unmodifiedArgumentsRegister(argumentsRegister).offset();

    JSValue arguments = JSValue(Arguments::create(callFrame->vm(), callFrame));
    callFrame->uncheckedR(argumentsRegister.offset()) = arguments;
    callFrame->uncheckedR(realArgumentsRegister) = arguments;
    
    ASSERT(callFrame->uncheckedR(realArgumentsRegister).jsValue().inherits(Arguments::info()));
    return JSValue::encode(callFrame->uncheckedR(realArgumentsRegister).jsValue());
}

JSValue JSActivation::argumentsGetter(ExecState*, JSValue slotBase, PropertyName)
{
    JSActivation* activation = jsCast<JSActivation*>(slotBase);
    if (activation->isTornOff())
        return jsUndefined();

    CallFrame* callFrame = CallFrame::create(reinterpret_cast<Register*>(activation->m_registers));
    int argumentsRegister = callFrame->codeBlock()->argumentsRegister();
    if (JSValue arguments = callFrame->uncheckedR(argumentsRegister).jsValue())
        return arguments;
    int realArgumentsRegister = unmodifiedArgumentsRegister(argumentsRegister);

    JSValue arguments = JSValue(Arguments::create(callFrame->vm(), callFrame));
    callFrame->uncheckedR(argumentsRegister) = arguments;
    callFrame->uncheckedR(realArgumentsRegister) = arguments;
    
    ASSERT(callFrame->uncheckedR(realArgumentsRegister).jsValue().inherits(Arguments::info()));
    return callFrame->uncheckedR(realArgumentsRegister).jsValue();
}

void JSActivation::getOwnNonIndexPropertyNames(JSObject* object, ExecState* exec, PropertyNameArray& propertyNames, EnumerationMode mode)
{
    JSActivation* thisObject = jsCast<JSActivation*>(object);

    CallFrame* callFrame = CallFrame::create(reinterpret_cast<Register*>(thisObject->m_registers));
    if (mode == IncludeDontEnumProperties && !thisObject->isTornOff() && (callFrame->codeBlock()->usesArguments() || callFrame->codeBlock()->usesEval()))
        propertyNames.add(exec->propertyNames().arguments);

    {
        ConcurrentJITLocker locker(thisObject->symbolTable()->m_lock);
        SymbolTable::Map::iterator end = thisObject->symbolTable()->end(locker);
        for (SymbolTable::Map::iterator it = thisObject->symbolTable()->begin(locker); it != end; ++it) {
            if (it->value.getAttributes() & DontEnum && mode != IncludeDontEnumProperties)
                continue;
            if (!thisObject->isValid(it->value))
                continue;
            propertyNames.add(Identifier(exec, it->key.get()));
        }
    }
    // Skip the JSVariableObject implementation of getOwnNonIndexPropertyNames
    JSObject::getOwnNonIndexPropertyNames(thisObject, exec, propertyNames, mode);
}

void ShadowChicken::update(VM& vm, ExecState* exec)
{
    if (verbose) {
        dataLog("Running update on: ", *this, "\n");
        WTFReportBacktrace();
    }
    
    const unsigned logCursorIndex = m_logCursor - m_log;
    
    // We need to figure out how to reconcile the current machine stack with our shadow stack. We do
    // that by figuring out how much of the shadow stack to pop. We apply three different rules. The
    // precise rule relies on the log. The log contains caller frames, which means that we know
    // where we bottomed out after making any call. If we bottomed out but made no calls then 'exec'
    // will tell us. That's why "highestPointSinceLastTime" will go no lower than exec. The third
    // rule, based on comparing to the current real stack, is executed in a later loop.
    CallFrame* highestPointSinceLastTime = exec;
    for (unsigned i = logCursorIndex; i--;) {
        Packet packet = m_log[i];
        if (packet.isPrologue()) {
            CallFrame* watermark;
            if (i && m_log[i - 1].isTail())
                watermark = packet.frame;
            else
                watermark = packet.callerFrame;
            highestPointSinceLastTime = std::max(highestPointSinceLastTime, watermark);
        }
    }
    
    if (verbose)
        dataLog("Highest point since last time: ", RawPointer(highestPointSinceLastTime), "\n");
    
    while (!m_stack.isEmpty() && (m_stack.last().frame < highestPointSinceLastTime || m_stack.last().isTailDeleted))
        m_stack.removeLast();
    
    if (verbose)
        dataLog("    Revised stack: ", listDump(m_stack), "\n");
    
    // It's possible that the top of stack is now tail-deleted. The stack no longer contains any
    // frames below the log's high watermark. That means that we just need to look for the first
    // occurence of a tail packet for the current stack top.
    if (!m_stack.isEmpty()) {
        ASSERT(!m_stack.last().isTailDeleted);
        for (unsigned i = 0; i < logCursorIndex; ++i) {
            Packet& packet = m_log[i];
            if (packet.isTail() && packet.frame == m_stack.last().frame) {
                Frame& frame = m_stack.last();
                frame.thisValue = packet.thisValue;
                frame.scope = packet.scope;
                frame.codeBlock = packet.codeBlock;
                frame.callSiteIndex = packet.callSiteIndex;
                frame.isTailDeleted = true;
                break;
            }
        }
    }

    
    if (verbose)
        dataLog("    Revised stack: ", listDump(m_stack), "\n");
    
    // The log-based and exec-based rules require that ShadowChicken was enabled. The point of
    // ShadowChicken is to give sensible-looking results even if we had not logged. This means that
    // we need to reconcile the shadow stack and the real stack by actually looking at the real
    // stack. This reconciliation allows the shadow stack to have extra tail-deleted frames, but it
    // forbids it from diverging from the real stack on normal frames.
    if (!m_stack.isEmpty()) {
        Vector<Frame> stackRightNow;
        StackVisitor::visit(
            exec, [&] (StackVisitor& visitor) -> StackVisitor::Status {
                if (visitor->isInlinedFrame())
                    return StackVisitor::Continue;
                if (visitor->isWasmFrame()) {
                    // FIXME: Make shadow chicken work with Wasm.
                    // https://bugs.webkit.org/show_bug.cgi?id=165441
                    return StackVisitor::Continue;
                }

                bool isTailDeleted = false;
                // FIXME: Make shadow chicken work with Wasm.
                // https://bugs.webkit.org/show_bug.cgi?id=165441
                stackRightNow.append(Frame(jsCast<JSObject*>(visitor->callee()), visitor->callFrame(), isTailDeleted));
                return StackVisitor::Continue;
            });
        stackRightNow.reverse();
        
        if (verbose)
            dataLog("    Stack right now: ", listDump(stackRightNow), "\n");
        
        unsigned shadowIndex = 0;
        unsigned rightNowIndex = 0;
        while (shadowIndex < m_stack.size() && rightNowIndex < stackRightNow.size()) {
            if (m_stack[shadowIndex].isTailDeleted) {
                shadowIndex++;
                continue;
            }

            // We specifically don't use operator== here because we are using a less
            // strict filter on equality of frames. For example, the scope pointer
            // could change, but we wouldn't want to consider the frames different entities
            // because of that because it's natural for the program to change scopes.
//.........这里部分代码省略.........

JSObject* addErrorInfo(ExecState* exec, JSObject* error, int line, const SourceCode& source)
{
    JSGlobalData* globalData = &exec->globalData();

    addErrorInfo(globalData, error, line, source);

    UStringBuilder stackString;
    JSArray* stackArray = constructEmptyArray(exec);
    CallFrame* frame = exec;

    stackString.append(error->toString(exec));

    bool functionKnown;
    ReturnAddressPtr pc;

    while (!frame->hasHostCallFrameFlag()) {
        CodeBlock* codeBlock = frame->codeBlock();
        JSObject* arrayItem = constructEmptyObject(exec);

        stackString.append("\n    at ");

        JSObject* callee = frame->callee();
        UString functionName;

        if (callee && callee->inherits(&JSFunction::s_info)) {
            functionName = asFunction(callee)->calculatedDisplayName(exec);
            functionKnown = !functionName.isEmpty();
        } else {
            functionKnown = false;
        }

        if (functionKnown) {
            stackString.append(functionName);
            stackString.append(" (");

            arrayItem->putWithAttributes(
                globalData, Identifier(globalData, functionPropertyName),
                jsString(globalData, functionName), ReadOnly | DontDelete
            );
        }

        UString sourceURL = codeBlock->ownerExecutable()->sourceURL();

        arrayItem->putWithAttributes(
            globalData, Identifier(globalData, sourceURLPropertyName),
            jsString(globalData, sourceURL), ReadOnly | DontDelete
        );

        stackString.append(sourceURL);
        stackString.append(":");

        if (frame != exec) {
            line = codeBlock->lineNumberForBytecodeOffset(codeBlock->bytecodeOffset(pc));
        }

        arrayItem->putWithAttributes(
            globalData, Identifier(globalData, linePropertyName),
            jsNumber(line), ReadOnly | DontDelete
        );

        stackString.append(UString::number(line));

        if (functionKnown) {
            stackString.append(")");
        }

        stackArray->push(exec, JSValue(arrayItem));

        pc = frame->returnPC();
        frame = frame->callerFrame();
    }

    error->putWithAttributes(
        globalData, Identifier(globalData, stackPropertyName),
        jsString(globalData, stackString.toUString()), ReadOnly | DontDelete
    );

    error->putWithAttributes(
        globalData, Identifier(globalData, "stackArray"),
        stackArray, ReadOnly | DontDelete
    );

    return error;
}