C++ CacheIRWriter::loadObject方法代码示例

static void
GeneratePrototypeGuards(CacheIRWriter& writer, JSObject* obj, JSObject* holder, ObjOperandId objId)
{
    // The guards here protect against the effects of JSObject::swap(). If the
    // prototype chain is directly altered, then TI will toss the jitcode, so we
    // don't have to worry about it, and any other change to the holder, or
    // adding a shadowing property will result in reshaping the holder, and thus
    // the failure of the shape guard.
    MOZ_ASSERT(obj != holder);

    if (obj->hasUncacheableProto()) {
        // If the shape does not imply the proto, emit an explicit proto guard.
        writer.guardProto(objId, obj->getProto());
    }

    JSObject* pobj = IsCacheableDOMProxy(obj)
                     ? obj->getTaggedProto().toObjectOrNull()
                     : obj->getProto();
    if (!pobj)
        return;

    while (pobj != holder) {
        if (pobj->hasUncacheableProto()) {
            ObjOperandId protoId = writer.loadObject(pobj);
            if (pobj->isSingleton()) {
                // Singletons can have their group's |proto| mutated directly.
                writer.guardProto(protoId, pobj->getProto());
            } else {
                writer.guardGroup(protoId, pobj->group());
            }
        }
        pobj = pobj->getProto();
    }
}

bool
GetPropIRGenerator::tryAttachModuleNamespace(CacheIRWriter& writer, HandleObject obj,
                                             ObjOperandId objId)
{
    MOZ_ASSERT(!emitted_);

    if (!obj->is<ModuleNamespaceObject>())
        return true;

    Rooted<ModuleNamespaceObject*> ns(cx_, &obj->as<ModuleNamespaceObject>());
    RootedModuleEnvironmentObject env(cx_);
    RootedShape shape(cx_);
    if (!ns->bindings().lookup(NameToId(name_), env.address(), shape.address()))
        return true;

    // Don't emit a stub until the target binding has been initialized.
    if (env->getSlot(shape->slot()).isMagic(JS_UNINITIALIZED_LEXICAL))
        return true;

    if (IsIonEnabled(cx_))
        EnsureTrackPropertyTypes(cx_, env, shape->propid());

    emitted_ = true;

    // Check for the specific namespace object.
    writer.guardSpecificObject(objId, ns);

    ObjOperandId envId = writer.loadObject(env);
    EmitLoadSlotResult(writer, envId, env, shape);
    return true;
}

static void
EmitCallGetterResult(CacheIRWriter& writer, JSObject* obj, JSObject* holder,
                     Shape* shape, ObjOperandId objId)
{
    Maybe<ObjOperandId> expandoId;
    TestMatchingReceiver(writer, obj, shape, objId, &expandoId);

    if (obj != holder) {
        GeneratePrototypeGuards(writer, obj, holder, objId);

        // Guard on the holder's shape.
        ObjOperandId holderId = writer.loadObject(holder);
        writer.guardShape(holderId, holder->as<NativeObject>().lastProperty());
    }

    EmitCallGetterResultNoGuards(writer, obj, holder, shape, objId);
}