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// 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/builtins/builtins-async-gen.h"
#include "src/builtins/builtins-utils-gen.h"
#include "src/builtins/builtins.h"
#include "src/codegen/code-stub-assembler.h"
#include "src/objects/js-generator.h"
#include "src/objects/js-promise.h"
#include "src/objects/objects-inl.h"
namespace v8 {
namespace internal {
class AsyncFunctionBuiltinsAssembler : public AsyncBuiltinsAssembler {
public:
explicit AsyncFunctionBuiltinsAssembler(compiler::CodeAssemblerState* state)
: AsyncBuiltinsAssembler(state) {}
protected:
template <typename Descriptor>
void AsyncFunctionAwait(const bool is_predicted_as_caught);
void AsyncFunctionAwaitResumeClosure(
Node* const context, Node* const sent_value,
JSGeneratorObject::ResumeMode resume_mode);
};
void AsyncFunctionBuiltinsAssembler::AsyncFunctionAwaitResumeClosure(
Node* context, Node* sent_value,
JSGeneratorObject::ResumeMode resume_mode) {
DCHECK(resume_mode == JSGeneratorObject::kNext ||
resume_mode == JSGeneratorObject::kThrow);
TNode<JSAsyncFunctionObject> async_function_object =
CAST(LoadContextElement(context, Context::EXTENSION_INDEX));
// Push the promise for the {async_function_object} back onto the catch
// prediction stack to handle exceptions thrown after resuming from the
// await properly.
Label if_instrumentation(this, Label::kDeferred),
if_instrumentation_done(this);
Branch(IsDebugActive(), &if_instrumentation, &if_instrumentation_done);
BIND(&if_instrumentation);
{
TNode<JSPromise> promise = LoadObjectField<JSPromise>(
async_function_object, JSAsyncFunctionObject::kPromiseOffset);
CallRuntime(Runtime::kDebugAsyncFunctionResumed, context, promise);
Goto(&if_instrumentation_done);
}
BIND(&if_instrumentation_done);
// Inline version of GeneratorPrototypeNext / GeneratorPrototypeReturn with
// unnecessary runtime checks removed.
// Ensure that the {async_function_object} is neither closed nor running.
CSA_SLOW_ASSERT(
this, SmiGreaterThan(
LoadObjectField<Smi>(async_function_object,
JSGeneratorObject::kContinuationOffset),
SmiConstant(JSGeneratorObject::kGeneratorClosed)));
// Remember the {resume_mode} for the {async_function_object}.
StoreObjectFieldNoWriteBarrier(async_function_object,
JSGeneratorObject::kResumeModeOffset,
SmiConstant(resume_mode));
// Resume the {receiver} using our trampoline.
Callable callable = CodeFactory::ResumeGenerator(isolate());
CallStub(callable, context, sent_value, async_function_object);
// The resulting Promise is a throwaway, so it doesn't matter what it
// resolves to. What is important is that we don't end up keeping the
// whole chain of intermediate Promises alive by returning the return value
// of ResumeGenerator, as that would create a memory leak.
}
TF_BUILTIN(AsyncFunctionEnter, AsyncFunctionBuiltinsAssembler) {
TNode<JSFunction> closure = CAST(Parameter(Descriptor::kClosure));
TNode<Object> receiver = CAST(Parameter(Descriptor::kReceiver));
TNode<Context> context = CAST(Parameter(Descriptor::kContext));
// Compute the number of registers and parameters.
TNode<SharedFunctionInfo> shared = LoadObjectField<SharedFunctionInfo>(
closure, JSFunction::kSharedFunctionInfoOffset);
TNode<IntPtrT> formal_parameter_count = ChangeInt32ToIntPtr(
LoadObjectField(shared, SharedFunctionInfo::kFormalParameterCountOffset,
MachineType::Uint16()));
TNode<BytecodeArray> bytecode_array =
LoadSharedFunctionInfoBytecodeArray(shared);
TNode<IntPtrT> frame_size = ChangeInt32ToIntPtr(LoadObjectField(
bytecode_array, BytecodeArray::kFrameSizeOffset, MachineType::Int32()));
TNode<IntPtrT> parameters_and_register_length =
Signed(IntPtrAdd(WordSar(frame_size, IntPtrConstant(kTaggedSizeLog2)),
formal_parameter_count));
// Allocate and initialize the register file.
TNode<FixedArrayBase> parameters_and_registers =
AllocateFixedArray(HOLEY_ELEMENTS, parameters_and_register_length,
INTPTR_PARAMETERS, kAllowLargeObjectAllocation);
FillFixedArrayWithValue(HOLEY_ELEMENTS, parameters_and_registers,
IntPtrConstant(0), parameters_and_register_length,
RootIndex::kUndefinedValue);
// Allocate space for the promise, the async function object.
TNode<IntPtrT> size = IntPtrConstant(JSPromise::kSizeWithEmbedderFields +
JSAsyncFunctionObject::kSize);
TNode<HeapObject> base = AllocateInNewSpace(size);
// Initialize the promise.
TNode<NativeContext> native_context = LoadNativeContext(context);
TNode<JSFunction> promise_function =
CAST(LoadContextElement(native_context, Context::PROMISE_FUNCTION_INDEX));
TNode<Map> promise_map = LoadObjectField<Map>(
promise_function, JSFunction::kPrototypeOrInitialMapOffset);
TNode<JSPromise> promise = UncheckedCast<JSPromise>(
InnerAllocate(base, JSAsyncFunctionObject::kSize));
StoreMapNoWriteBarrier(promise, promise_map);
StoreObjectFieldRoot(promise, JSPromise::kPropertiesOrHashOffset,
RootIndex::kEmptyFixedArray);
StoreObjectFieldRoot(promise, JSPromise::kElementsOffset,
RootIndex::kEmptyFixedArray);
PromiseInit(promise);
// Initialize the async function object.
TNode<Map> async_function_object_map = CAST(LoadContextElement(
native_context, Context::ASYNC_FUNCTION_OBJECT_MAP_INDEX));
TNode<JSAsyncFunctionObject> async_function_object =
UncheckedCast<JSAsyncFunctionObject>(base);
StoreMapNoWriteBarrier(async_function_object, async_function_object_map);
StoreObjectFieldRoot(async_function_object,
JSAsyncFunctionObject::kPropertiesOrHashOffset,
RootIndex::kEmptyFixedArray);
StoreObjectFieldRoot(async_function_object,
JSAsyncFunctionObject::kElementsOffset,
RootIndex::kEmptyFixedArray);
StoreObjectFieldNoWriteBarrier(
async_function_object, JSAsyncFunctionObject::kFunctionOffset, closure);
StoreObjectFieldNoWriteBarrier(
async_function_object, JSAsyncFunctionObject::kContextOffset, context);
StoreObjectFieldNoWriteBarrier(
async_function_object, JSAsyncFunctionObject::kReceiverOffset, receiver);
StoreObjectFieldNoWriteBarrier(async_function_object,
JSAsyncFunctionObject::kInputOrDebugPosOffset,
SmiConstant(0));
StoreObjectFieldNoWriteBarrier(async_function_object,
JSAsyncFunctionObject::kResumeModeOffset,
SmiConstant(JSAsyncFunctionObject::kNext));
StoreObjectFieldNoWriteBarrier(
async_function_object, JSAsyncFunctionObject::kContinuationOffset,
SmiConstant(JSAsyncFunctionObject::kGeneratorExecuting));
StoreObjectFieldNoWriteBarrier(
async_function_object,
JSAsyncFunctionObject::kParametersAndRegistersOffset,
parameters_and_registers);
StoreObjectFieldNoWriteBarrier(
async_function_object, JSAsyncFunctionObject::kPromiseOffset, promise);
// Fire promise hooks if enabled and push the Promise under construction
// in an async function on the catch prediction stack to handle exceptions
// thrown before the first await.
Label if_instrumentation(this, Label::kDeferred),
if_instrumentation_done(this);
Branch(IsPromiseHookEnabledOrDebugIsActiveOrHasAsyncEventDelegate(),
&if_instrumentation, &if_instrumentation_done);
BIND(&if_instrumentation);
{
CallRuntime(Runtime::kDebugAsyncFunctionEntered, context, promise);
Goto(&if_instrumentation_done);
}
BIND(&if_instrumentation_done);
Return(async_function_object);
}
TF_BUILTIN(AsyncFunctionReject, AsyncFunctionBuiltinsAssembler) {
TNode<JSAsyncFunctionObject> async_function_object =
CAST(Parameter(Descriptor::kAsyncFunctionObject));
TNode<Object> reason = CAST(Parameter(Descriptor::kReason));
TNode<Oddball> can_suspend = CAST(Parameter(Descriptor::kCanSuspend));
TNode<Context> context = CAST(Parameter(Descriptor::kContext));
TNode<JSPromise> promise = LoadObjectField<JSPromise>(
async_function_object, JSAsyncFunctionObject::kPromiseOffset);
// Reject the {promise} for the given {reason}, disabling the
// additional debug event for the rejection since a debug event
// already happend for the exception that got us here.
CallBuiltin(Builtins::kRejectPromise, context, promise, reason,
FalseConstant());
Label if_debugging(this, Label::kDeferred);
GotoIf(HasAsyncEventDelegate(), &if_debugging);
GotoIf(IsDebugActive(), &if_debugging);
Return(promise);
BIND(&if_debugging);
TailCallRuntime(Runtime::kDebugAsyncFunctionFinished, context, can_suspend,
promise);
}
TF_BUILTIN(AsyncFunctionResolve, AsyncFunctionBuiltinsAssembler) {
TNode<JSAsyncFunctionObject> async_function_object =
CAST(Parameter(Descriptor::kAsyncFunctionObject));
TNode<Object> value = CAST(Parameter(Descriptor::kValue));
TNode<Oddball> can_suspend = CAST(Parameter(Descriptor::kCanSuspend));
TNode<Context> context = CAST(Parameter(Descriptor::kContext));
TNode<JSPromise> promise = LoadObjectField<JSPromise>(
async_function_object, JSAsyncFunctionObject::kPromiseOffset);
CallBuiltin(Builtins::kResolvePromise, context, promise, value);
Label if_debugging(this, Label::kDeferred);
GotoIf(HasAsyncEventDelegate(), &if_debugging);
GotoIf(IsDebugActive(), &if_debugging);
Return(promise);
BIND(&if_debugging);
TailCallRuntime(Runtime::kDebugAsyncFunctionFinished, context, can_suspend,
promise);
}
// AsyncFunctionReject and AsyncFunctionResolve are both required to return
// the promise instead of the result of RejectPromise or ResolvePromise
// respectively from a lazy deoptimization.
TF_BUILTIN(AsyncFunctionLazyDeoptContinuation, AsyncFunctionBuiltinsAssembler) {
TNode<JSPromise> promise = CAST(Parameter(Descriptor::kPromise));
Return(promise);
}
TF_BUILTIN(AsyncFunctionAwaitRejectClosure, AsyncFunctionBuiltinsAssembler) {
CSA_ASSERT_JS_ARGC_EQ(this, 1);
Node* const sentError = Parameter(Descriptor::kSentError);
Node* const context = Parameter(Descriptor::kContext);
AsyncFunctionAwaitResumeClosure(context, sentError,
JSGeneratorObject::kThrow);
Return(UndefinedConstant());
}
TF_BUILTIN(AsyncFunctionAwaitResolveClosure, AsyncFunctionBuiltinsAssembler) {
CSA_ASSERT_JS_ARGC_EQ(this, 1);
Node* const sentValue = Parameter(Descriptor::kSentValue);
Node* const context = Parameter(Descriptor::kContext);
AsyncFunctionAwaitResumeClosure(context, sentValue, JSGeneratorObject::kNext);
Return(UndefinedConstant());
}
// ES#abstract-ops-async-function-await
// AsyncFunctionAwait ( value )
// Shared logic for the core of await. The parser desugars
// await value
// into
// yield AsyncFunctionAwait{Caught,Uncaught}(.generator_object, value)
// The 'value' parameter is the value; the .generator_object stands in
// for the asyncContext.
template <typename Descriptor>
void AsyncFunctionBuiltinsAssembler::AsyncFunctionAwait(
const bool is_predicted_as_caught) {
TNode<JSAsyncFunctionObject> async_function_object =
CAST(Parameter(Descriptor::kAsyncFunctionObject));
TNode<Object> value = CAST(Parameter(Descriptor::kValue));
TNode<Context> context = CAST(Parameter(Descriptor::kContext));
TNode<Object> outer_promise = LoadObjectField(
async_function_object, JSAsyncFunctionObject::kPromiseOffset);
Label after_debug_hook(this), call_debug_hook(this, Label::kDeferred);
GotoIf(HasAsyncEventDelegate(), &call_debug_hook);
Goto(&after_debug_hook);
BIND(&after_debug_hook);
Await(context, async_function_object, value, outer_promise,
Context::ASYNC_FUNCTION_AWAIT_RESOLVE_SHARED_FUN,
Context::ASYNC_FUNCTION_AWAIT_REJECT_SHARED_FUN,
is_predicted_as_caught);
// Return outer promise to avoid adding an load of the outer promise before
// suspending in BytecodeGenerator.
Return(outer_promise);
BIND(&call_debug_hook);
CallRuntime(Runtime::kDebugAsyncFunctionSuspended, context, outer_promise);
Goto(&after_debug_hook);
}
// Called by the parser from the desugaring of 'await' when catch
// prediction indicates that there is a locally surrounding catch block.
TF_BUILTIN(AsyncFunctionAwaitCaught, AsyncFunctionBuiltinsAssembler) {
static const bool kIsPredictedAsCaught = true;
AsyncFunctionAwait<Descriptor>(kIsPredictedAsCaught);
}
// Called by the parser from the desugaring of 'await' when catch
// prediction indicates no locally surrounding catch block.
TF_BUILTIN(AsyncFunctionAwaitUncaught, AsyncFunctionBuiltinsAssembler) {
static const bool kIsPredictedAsCaught = false;
AsyncFunctionAwait<Descriptor>(kIsPredictedAsCaught);
}
} // namespace internal
} // namespace v8