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// Copyright 2014 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/runtime/runtime-utils.h"
#include "src/arguments.h"
#include "src/factory.h"
#include "src/frames-inl.h"
#include "src/objects-inl.h"
namespace v8 {
namespace internal {
RUNTIME_FUNCTION(Runtime_CreateJSGeneratorObject) {
HandleScope scope(isolate);
DCHECK(args.length() == 0);
JavaScriptFrameIterator it(isolate);
JavaScriptFrame* frame = it.frame();
Handle<JSFunction> function(frame->function());
RUNTIME_ASSERT(function->shared()->is_generator());
Handle<JSGeneratorObject> generator;
DCHECK(!frame->IsConstructor());
generator = isolate->factory()->NewJSGeneratorObject(function);
generator->set_function(*function);
generator->set_context(Context::cast(frame->context()));
generator->set_receiver(frame->receiver());
generator->set_continuation(0);
generator->set_operand_stack(isolate->heap()->empty_fixed_array());
return *generator;
}
RUNTIME_FUNCTION(Runtime_SuspendJSGeneratorObject) {
HandleScope handle_scope(isolate);
DCHECK(args.length() == 1);
CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator_object, 0);
JavaScriptFrameIterator stack_iterator(isolate);
JavaScriptFrame* frame = stack_iterator.frame();
RUNTIME_ASSERT(frame->function()->shared()->is_generator());
DCHECK_EQ(frame->function(), generator_object->function());
DCHECK(frame->function()->shared()->is_compiled());
DCHECK(!frame->function()->IsOptimized());
// The caller should have saved the context and continuation already.
DCHECK_EQ(generator_object->context(), Context::cast(frame->context()));
DCHECK_LT(0, generator_object->continuation());
// We expect there to be at least two values on the operand stack: the return
// value of the yield expression, and the arguments to this runtime call.
// Neither of those should be saved.
int operands_count = frame->ComputeOperandsCount();
DCHECK_GE(operands_count, 1 + args.length());
operands_count -= 1 + args.length();
if (operands_count == 0) {
// Although it's semantically harmless to call this function with an
// operands_count of zero, it is also unnecessary.
DCHECK_EQ(generator_object->operand_stack(),
isolate->heap()->empty_fixed_array());
} else {
Handle<FixedArray> operand_stack =
isolate->factory()->NewFixedArray(operands_count);
frame->SaveOperandStack(*operand_stack);
generator_object->set_operand_stack(*operand_stack);
}
return isolate->heap()->undefined_value();
}
// Note that this function is the slow path for resuming generators. It is only
// called if the suspended activation had operands on the stack, stack handlers
// needing rewinding, or if the resume should throw an exception. The fast path
// is handled directly in FullCodeGenerator::EmitGeneratorResume(), which is
// inlined into GeneratorNext, GeneratorReturn, and GeneratorThrow.
// EmitGeneratorResume is called in any case, as it needs to reconstruct the
// stack frame and make space for arguments and operands.
RUNTIME_FUNCTION(Runtime_ResumeJSGeneratorObject) {
SealHandleScope shs(isolate);
DCHECK(args.length() == 3);
CONVERT_ARG_CHECKED(JSGeneratorObject, generator_object, 0);
CONVERT_ARG_CHECKED(Object, value, 1);
CONVERT_SMI_ARG_CHECKED(resume_mode_int, 2);
JavaScriptFrameIterator stack_iterator(isolate);
JavaScriptFrame* frame = stack_iterator.frame();
DCHECK_EQ(frame->function(), generator_object->function());
DCHECK(frame->function()->shared()->is_compiled());
DCHECK(!frame->function()->IsOptimized());
STATIC_ASSERT(JSGeneratorObject::kGeneratorExecuting < 0);
STATIC_ASSERT(JSGeneratorObject::kGeneratorClosed == 0);
Code* code = generator_object->function()->shared()->code();
int offset = generator_object->continuation();
DCHECK_GT(offset, 0);
frame->set_pc(code->instruction_start() + offset);
if (FLAG_enable_embedded_constant_pool) {
frame->set_constant_pool(code->constant_pool());
}
generator_object->set_continuation(JSGeneratorObject::kGeneratorExecuting);
FixedArray* operand_stack = generator_object->operand_stack();
int operands_count = operand_stack->length();
if (operands_count != 0) {
frame->RestoreOperandStack(operand_stack);
generator_object->set_operand_stack(isolate->heap()->empty_fixed_array());
}
JSGeneratorObject::ResumeMode resume_mode =
static_cast<JSGeneratorObject::ResumeMode>(resume_mode_int);
switch (resume_mode) {
// Note: this looks like NEXT and RETURN are the same but RETURN receives
// special treatment in the generator code (to which we return here).
case JSGeneratorObject::NEXT:
case JSGeneratorObject::RETURN:
return value;
case JSGeneratorObject::THROW:
return isolate->Throw(value);
}
UNREACHABLE();
return isolate->ThrowIllegalOperation();
}
RUNTIME_FUNCTION(Runtime_GeneratorClose) {
HandleScope scope(isolate);
DCHECK(args.length() == 1);
CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0);
generator->set_continuation(JSGeneratorObject::kGeneratorClosed);
return isolate->heap()->undefined_value();
}
// Returns function of generator activation.
RUNTIME_FUNCTION(Runtime_GeneratorGetFunction) {
HandleScope scope(isolate);
DCHECK(args.length() == 1);
CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0);
return generator->function();
}
// Returns receiver of generator activation.
RUNTIME_FUNCTION(Runtime_GeneratorGetReceiver) {
HandleScope scope(isolate);
DCHECK(args.length() == 1);
CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0);
return generator->receiver();
}
// Returns input of generator activation.
RUNTIME_FUNCTION(Runtime_GeneratorGetInput) {
HandleScope scope(isolate);
DCHECK(args.length() == 1);
CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0);
return generator->input();
}
// Returns generator continuation as a PC offset, or the magic -1 or 0 values.
RUNTIME_FUNCTION(Runtime_GeneratorGetContinuation) {
HandleScope scope(isolate);
DCHECK(args.length() == 1);
CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0);
return Smi::FromInt(generator->continuation());
}
RUNTIME_FUNCTION(Runtime_GeneratorGetSourcePosition) {
HandleScope scope(isolate);
DCHECK(args.length() == 1);
CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0);
if (generator->is_suspended()) {
Handle<Code> code(generator->function()->code(), isolate);
int offset = generator->continuation();
RUNTIME_ASSERT(0 <= offset && offset < code->instruction_size());
return Smi::FromInt(code->SourcePosition(offset));
}
return isolate->heap()->undefined_value();
}
// Optimization for builtins calling any of the following three functions is
// disabled in js/generator.js and compiler.cc, hence they are unreachable.
RUNTIME_FUNCTION(Runtime_GeneratorNext) {
UNREACHABLE();
return nullptr;
}
RUNTIME_FUNCTION(Runtime_GeneratorReturn) {
UNREACHABLE();
return nullptr;
}
RUNTIME_FUNCTION(Runtime_GeneratorThrow) {
UNREACHABLE();
return nullptr;
}
} // namespace internal
} // namespace v8
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