// Copyright 2017 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #include "src/base/optional.h" #include "src/builtins/builtins-async-gen.h" #include "src/builtins/builtins-utils-gen.h" #include "src/builtins/builtins.h" #include "src/codegen/code-factory.h" #include "src/codegen/code-stub-assembler.h" #include "src/execution/frames-inl.h" namespace v8 { namespace internal { using compiler::Node; namespace { class AsyncFromSyncBuiltinsAssembler : public AsyncBuiltinsAssembler { public: explicit AsyncFromSyncBuiltinsAssembler(compiler::CodeAssemblerState* state) : AsyncBuiltinsAssembler(state) {} void ThrowIfNotAsyncFromSyncIterator(const TNode<Context> context, const TNode<Object> object, Label* if_exception, TVariable<Object>* var_exception, const char* method_name); using UndefinedMethodHandler = std::function<void(const TNode<NativeContext> native_context, const TNode<JSPromise> promise, Label* if_exception)>; using SyncIteratorNodeGenerator = std::function<TNode<Object>(TNode<JSReceiver>)>; void Generate_AsyncFromSyncIteratorMethod( const TNode<Context> context, const TNode<Object> iterator, const TNode<Object> sent_value, const SyncIteratorNodeGenerator& get_method, const UndefinedMethodHandler& if_method_undefined, const char* operation_name, Label::Type reject_label_type = Label::kDeferred, base::Optional<TNode<Object>> initial_exception_value = base::nullopt); void Generate_AsyncFromSyncIteratorMethod( const TNode<Context> context, const TNode<Object> iterator, const TNode<Object> sent_value, Handle<String> name, const UndefinedMethodHandler& if_method_undefined, const char* operation_name, Label::Type reject_label_type = Label::kDeferred, base::Optional<TNode<Object>> initial_exception_value = base::nullopt) { auto get_method = [=](const TNode<JSReceiver> sync_iterator) { return GetProperty(context, sync_iterator, name); }; return Generate_AsyncFromSyncIteratorMethod( context, iterator, sent_value, get_method, if_method_undefined, operation_name, reject_label_type, initial_exception_value); } // Load "value" and "done" from an iterator result object. If an exception // is thrown at any point, jumps to the `if_exception` label with exception // stored in `var_exception`. // // Returns a Pair of Nodes, whose first element is the value of the "value" // property, and whose second element is the value of the "done" property, // converted to a Boolean if needed. std::pair<TNode<Object>, TNode<Oddball>> LoadIteratorResult( const TNode<Context> context, const TNode<NativeContext> native_context, const TNode<Object> iter_result, Label* if_exception, TVariable<Object>* var_exception); }; void AsyncFromSyncBuiltinsAssembler::ThrowIfNotAsyncFromSyncIterator( const TNode<Context> context, const TNode<Object> object, Label* if_exception, TVariable<Object>* var_exception, const char* method_name) { Label if_receiverisincompatible(this, Label::kDeferred), done(this); GotoIf(TaggedIsSmi(object), &if_receiverisincompatible); Branch(HasInstanceType(CAST(object), JS_ASYNC_FROM_SYNC_ITERATOR_TYPE), &done, &if_receiverisincompatible); BIND(&if_receiverisincompatible); { // If Type(O) is not Object, or if O does not have a [[SyncIterator]] // internal slot, then // Let badIteratorError be a new TypeError exception. TNode<HeapObject> error = CAST(MakeTypeError(MessageTemplate::kIncompatibleMethodReceiver, context, StringConstant(method_name), object)); // Perform ! Call(promiseCapability.[[Reject]], undefined, // « badIteratorError »). *var_exception = error; Goto(if_exception); } BIND(&done); } void AsyncFromSyncBuiltinsAssembler::Generate_AsyncFromSyncIteratorMethod( const TNode<Context> context, const TNode<Object> iterator, const TNode<Object> sent_value, const SyncIteratorNodeGenerator& get_method, const UndefinedMethodHandler& if_method_undefined, const char* operation_name, Label::Type reject_label_type, base::Optional<TNode<Object>> initial_exception_value) { const TNode<NativeContext> native_context = LoadNativeContext(context); const TNode<JSPromise> promise = AllocateAndInitJSPromise(context); TVARIABLE( Object, var_exception, initial_exception_value ? *initial_exception_value : UndefinedConstant()); Label reject_promise(this, reject_label_type); ThrowIfNotAsyncFromSyncIterator(context, iterator, &reject_promise, &var_exception, operation_name); TNode<JSAsyncFromSyncIterator> async_iterator = CAST(iterator); const TNode<JSReceiver> sync_iterator = LoadObjectField<JSReceiver>( async_iterator, JSAsyncFromSyncIterator::kSyncIteratorOffset); TNode<Object> method = get_method(sync_iterator); if (if_method_undefined) { Label if_isnotundefined(this); GotoIfNot(IsUndefined(method), &if_isnotundefined); if_method_undefined(native_context, promise, &reject_promise); BIND(&if_isnotundefined); } const TNode<Object> iter_result = CallJS( CodeFactory::Call(isolate()), context, method, sync_iterator, sent_value); GotoIfException(iter_result, &reject_promise, &var_exception); TNode<Object> value; TNode<Oddball> done; std::tie(value, done) = LoadIteratorResult( context, native_context, iter_result, &reject_promise, &var_exception); const TNode<JSFunction> promise_fun = CAST(LoadContextElement(native_context, Context::PROMISE_FUNCTION_INDEX)); CSA_ASSERT(this, IsConstructor(promise_fun)); // Let valueWrapper be PromiseResolve(%Promise%, « value »). const TNode<Object> value_wrapper = CallBuiltin( Builtins::kPromiseResolve, native_context, promise_fun, value); // IfAbruptRejectPromise(valueWrapper, promiseCapability). GotoIfException(value_wrapper, &reject_promise, &var_exception); // Let onFulfilled be a new built-in function object as defined in // Async Iterator Value Unwrap Functions. // Set onFulfilled.[[Done]] to throwDone. const TNode<JSFunction> on_fulfilled = CreateUnwrapClosure(native_context, done); // Perform ! PerformPromiseThen(valueWrapper, // onFulfilled, undefined, promiseCapability). Return(CallBuiltin(Builtins::kPerformPromiseThen, context, value_wrapper, on_fulfilled, UndefinedConstant(), promise)); BIND(&reject_promise); { const TNode<Object> exception = var_exception.value(); CallBuiltin(Builtins::kRejectPromise, context, promise, exception, TrueConstant()); Return(promise); } } std::pair<TNode<Object>, TNode<Oddball>> AsyncFromSyncBuiltinsAssembler::LoadIteratorResult( const TNode<Context> context, const TNode<NativeContext> native_context, const TNode<Object> iter_result, Label* if_exception, TVariable<Object>* var_exception) { Label if_fastpath(this), if_slowpath(this), merge(this), to_boolean(this), done(this), if_notanobject(this, Label::kDeferred); GotoIf(TaggedIsSmi(iter_result), &if_notanobject); const TNode<Map> iter_result_map = LoadMap(CAST(iter_result)); GotoIfNot(IsJSReceiverMap(iter_result_map), &if_notanobject); const TNode<Object> fast_iter_result_map = LoadContextElement(native_context, Context::ITERATOR_RESULT_MAP_INDEX); TVARIABLE(Object, var_value); TVARIABLE(Object, var_done); Branch(TaggedEqual(iter_result_map, fast_iter_result_map), &if_fastpath, &if_slowpath); BIND(&if_fastpath); { TNode<JSObject> fast_iter_result = CAST(iter_result); var_done = LoadObjectField(fast_iter_result, JSIteratorResult::kDoneOffset); var_value = LoadObjectField(fast_iter_result, JSIteratorResult::kValueOffset); Goto(&merge); } BIND(&if_slowpath); { // Let nextDone be IteratorComplete(nextResult). // IfAbruptRejectPromise(nextDone, promiseCapability). const TNode<Object> done = GetProperty(context, iter_result, factory()->done_string()); GotoIfException(done, if_exception, var_exception); // Let nextValue be IteratorValue(nextResult). // IfAbruptRejectPromise(nextValue, promiseCapability). const TNode<Object> value = GetProperty(context, iter_result, factory()->value_string()); GotoIfException(value, if_exception, var_exception); var_value = value; var_done = done; Goto(&merge); } BIND(&if_notanobject); { // Sync iterator result is not an object --- Produce a TypeError and jump // to the `if_exception` path. const TNode<Object> error = CAST(MakeTypeError( MessageTemplate::kIteratorResultNotAnObject, context, iter_result)); *var_exception = error; Goto(if_exception); } BIND(&merge); // Ensure `iterResult.done` is a Boolean. GotoIf(TaggedIsSmi(var_done.value()), &to_boolean); Branch(IsBoolean(CAST(var_done.value())), &done, &to_boolean); BIND(&to_boolean); { const TNode<Object> result = CallBuiltin(Builtins::kToBoolean, context, var_done.value()); var_done = result; Goto(&done); } BIND(&done); return std::make_pair(var_value.value(), CAST(var_done.value())); } } // namespace // https://tc39.github.io/proposal-async-iteration/ // Section #sec-%asyncfromsynciteratorprototype%.next TF_BUILTIN(AsyncFromSyncIteratorPrototypeNext, AsyncFromSyncBuiltinsAssembler) { const TNode<Object> iterator = CAST(Parameter(Descriptor::kReceiver)); const TNode<Object> value = CAST(Parameter(Descriptor::kValue)); const TNode<Context> context = CAST(Parameter(Descriptor::kContext)); auto get_method = [=](const TNode<JSReceiver> unused) { return LoadObjectField(CAST(iterator), JSAsyncFromSyncIterator::kNextOffset); }; Generate_AsyncFromSyncIteratorMethod( context, iterator, value, get_method, UndefinedMethodHandler(), "[Async-from-Sync Iterator].prototype.next"); } // https://tc39.github.io/proposal-async-iteration/ // Section #sec-%asyncfromsynciteratorprototype%.return TF_BUILTIN(AsyncFromSyncIteratorPrototypeReturn, AsyncFromSyncBuiltinsAssembler) { const TNode<Object> iterator = CAST(Parameter(Descriptor::kReceiver)); const TNode<Object> value = CAST(Parameter(Descriptor::kValue)); const TNode<Context> context = CAST(Parameter(Descriptor::kContext)); auto if_return_undefined = [=](const TNode<NativeContext> native_context, const TNode<JSPromise> promise, Label* if_exception) { // If return is undefined, then // Let iterResult be ! CreateIterResultObject(value, true) const TNode<Object> iter_result = CallBuiltin( Builtins::kCreateIterResultObject, context, value, TrueConstant()); // Perform ! Call(promiseCapability.[[Resolve]], undefined, « iterResult »). // IfAbruptRejectPromise(nextDone, promiseCapability). // Return promiseCapability.[[Promise]]. CallBuiltin(Builtins::kResolvePromise, context, promise, iter_result); Return(promise); }; Generate_AsyncFromSyncIteratorMethod( context, iterator, value, factory()->return_string(), if_return_undefined, "[Async-from-Sync Iterator].prototype.return"); } // https://tc39.github.io/proposal-async-iteration/ // Section #sec-%asyncfromsynciteratorprototype%.throw TF_BUILTIN(AsyncFromSyncIteratorPrototypeThrow, AsyncFromSyncBuiltinsAssembler) { const TNode<Object> iterator = CAST(Parameter(Descriptor::kReceiver)); const TNode<Object> reason = CAST(Parameter(Descriptor::kReason)); const TNode<Context> context = CAST(Parameter(Descriptor::kContext)); auto if_throw_undefined = [=](const TNode<NativeContext> native_context, const TNode<JSPromise> promise, Label* if_exception) { Goto(if_exception); }; Generate_AsyncFromSyncIteratorMethod( context, iterator, reason, factory()->throw_string(), if_throw_undefined, "[Async-from-Sync Iterator].prototype.throw", Label::kNonDeferred, reason); } } // namespace internal } // namespace v8