darling-JavaScriptCore/runtime/JSBoundFunction.cpp

/*
 * Copyright (C) 2011, 2016-2017 Apple Inc. All rights reserved.
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#include "config.h"
#include "JSBoundFunction.h"

#include "GetterSetter.h"
#include "JSGlobalObject.h"
#include "JSCInlines.h"

namespace JSC {

const ClassInfo JSBoundFunction::s_info = { "Function", &Base::s_info, 0, CREATE_METHOD_TABLE(JSBoundFunction) };

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));
}

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

    JSArray* boundArgs = boundFunction->boundArgs();

    MarkedArgumentBuffer args;
    if (boundArgs) {
        for (unsigned i = 0; i < boundArgs->length(); ++i)
            args.append(boundArgs->getIndexQuickly(i));
    }
    for (unsigned i = 0; i < exec->argumentCount(); ++i)
        args.append(exec->uncheckedArgument(i));

    JSObject* targetFunction = boundFunction->targetFunction();
    CallData callData;
    CallType callType = getCallData(targetFunction, callData);
    ASSERT(callType != CallType::None);
    return JSValue::encode(call(exec, targetFunction, callType, callData, boundFunction->boundThis(), args));
}

EncodedJSValue JSC_HOST_CALL boundThisNoArgsFunctionConstruct(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());
    ConstructData constructData;
    ConstructType constructType = getConstructData(targetFunction, constructData);
    ASSERT(constructType != ConstructType::None);
    return JSValue::encode(construct(exec, targetFunction, constructType, constructData, args));
}

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

    JSArray* boundArgs = boundFunction->boundArgs();

    MarkedArgumentBuffer args;
    if (boundArgs) {
        for (unsigned i = 0; i < boundArgs->length(); ++i)
            args.append(boundArgs->getIndexQuickly(i));
    }
    for (unsigned i = 0; i < exec->argumentCount(); ++i)
        args.append(exec->uncheckedArgument(i));

    JSObject* targetFunction = boundFunction->targetFunction();
    ConstructData constructData;
    ConstructType constructType = getConstructData(targetFunction, constructData);
    ASSERT(constructType != ConstructType::None);
    return JSValue::encode(construct(exec, targetFunction, constructType, constructData, args));
}

EncodedJSValue JSC_HOST_CALL isBoundFunction(ExecState* exec)
{
    return JSValue::encode(JSValue(static_cast<bool>(jsDynamicCast<JSBoundFunction*>(exec->uncheckedArgument(0)))));
}

EncodedJSValue JSC_HOST_CALL hasInstanceBoundFunction(ExecState* exec)
{
    JSBoundFunction* boundObject = jsCast<JSBoundFunction*>(exec->uncheckedArgument(0));
    JSValue value = exec->uncheckedArgument(1);

    return JSValue::encode(jsBoolean(boundObject->targetFunction()->hasInstance(exec, value)));
}

inline Structure* getBoundFunctionStructure(VM& vm, ExecState* exec, JSGlobalObject* globalObject, JSObject* targetFunction)
{
    auto scope = DECLARE_THROW_SCOPE(vm);
    JSValue prototype = targetFunction->getPrototype(vm, exec);
    RETURN_IF_EXCEPTION(scope, nullptr);
    JSFunction* targetJSFunction = jsDynamicCast<JSFunction*>(targetFunction);

    // We only cache the structure of the bound function if the bindee is a JSFunction since there
    // isn't any good place to put the structure on Internal Functions.
    if (targetJSFunction) {
        Structure* structure = targetJSFunction->rareData(vm)->getBoundFunctionStructure();
        if (structure && structure->storedPrototype() == prototype && structure->globalObject() == globalObject)
            return structure;
    }

    Structure* result = globalObject->boundFunctionStructure();

    // It would be nice if the structure map was keyed global objects in addition to the other things. Unfortunately, it is not
    // currently. Whoever works on caching structure changes for prototype transistions should consider this problem as well.
    // See: https://bugs.webkit.org/show_bug.cgi?id=152738
    if (prototype.isObject() && prototype.getObject()->globalObject() == globalObject) {
        result = vm.prototypeMap.emptyStructureForPrototypeFromBaseStructure(globalObject, prototype.getObject(), result);
        ASSERT_WITH_SECURITY_IMPLICATION(result->globalObject() == globalObject);
    } else
        result = Structure::create(vm, globalObject, prototype, result->typeInfo(), result->classInfo());

    if (targetJSFunction)
        targetJSFunction->rareData(vm)->setBoundFunctionStructure(vm, result);

    return result;
}

JSBoundFunction* JSBoundFunction::create(VM& vm, ExecState* exec, JSGlobalObject* globalObject, JSObject* targetFunction, JSValue boundThis, JSArray* boundArgs, int length, const String& name)
{
    auto scope = DECLARE_THROW_SCOPE(vm);
    ConstructData constructData;
    ConstructType constructType = JSC::getConstructData(targetFunction, constructData);
    bool canConstruct = constructType != ConstructType::None;
    
    bool slowCase = boundArgs || !getJSFunction(targetFunction);
    
    NativeExecutable* executable = vm.getHostFunction(
        slowCase ? boundFunctionCall : boundThisNoArgsFunctionCall,
        slowCase ? NoIntrinsic : BoundThisNoArgsFunctionCallIntrinsic,
        canConstruct ? (slowCase ? boundFunctionConstruct : boundThisNoArgsFunctionConstruct) : callHostFunctionAsConstructor, nullptr,
        name);
    Structure* structure = getBoundFunctionStructure(vm, exec, globalObject, targetFunction);
    RETURN_IF_EXCEPTION(scope, nullptr);
    JSBoundFunction* function = new (NotNull, allocateCell<JSBoundFunction>(vm.heap)) JSBoundFunction(vm, globalObject, structure, targetFunction, boundThis, boundArgs);

    function->finishCreation(vm, executable, length);
    return function;
}

bool JSBoundFunction::customHasInstance(JSObject* object, ExecState* exec, JSValue value)
{
    return jsCast<JSBoundFunction*>(object)->m_targetFunction->hasInstance(exec, value);
}

JSBoundFunction::JSBoundFunction(VM& vm, JSGlobalObject* globalObject, Structure* structure, JSObject* targetFunction, JSValue boundThis, JSArray* boundArgs)
    : Base(vm, globalObject, structure)
    , m_targetFunction(vm, this, targetFunction)
    , m_boundThis(vm, this, boundThis)
    , m_boundArgs(vm, this, boundArgs, WriteBarrier<JSArray>::MayBeNull)
{
}

void JSBoundFunction::finishCreation(VM& vm, NativeExecutable* executable, int length)
{
    String name; // We lazily create our 'name' string property.
    Base::finishCreation(vm, executable, length, name);
    ASSERT(inherits(info()));

    putDirectNonIndexAccessor(vm, vm.propertyNames->arguments, globalObject()->throwTypeErrorArgumentsCalleeAndCallerGetterSetter(), DontDelete | DontEnum | Accessor);
    putDirectNonIndexAccessor(vm, vm.propertyNames->caller, globalObject()->throwTypeErrorArgumentsCalleeAndCallerGetterSetter(), DontDelete | DontEnum | Accessor);
}

void JSBoundFunction::visitChildren(JSCell* cell, SlotVisitor& visitor)
{
    JSBoundFunction* thisObject = jsCast<JSBoundFunction*>(cell);
    ASSERT_GC_OBJECT_INHERITS(thisObject, info());
    Base::visitChildren(thisObject, visitor);

    visitor.append(thisObject->m_targetFunction);
    visitor.append(thisObject->m_boundThis);
    visitor.append(thisObject->m_boundArgs);
}

} // namespace JSC