1 // Copyright 2016 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "src/builtins/builtins.h"
6 #include "src/builtins/builtins-utils.h"
7
8 #include "src/code-factory.h"
9
10 namespace v8 {
11 namespace internal {
12
13 namespace {
14
Generate_GeneratorPrototypeResume(CodeStubAssembler * assembler,JSGeneratorObject::ResumeMode resume_mode,char const * const method_name)15 void Generate_GeneratorPrototypeResume(
16 CodeStubAssembler* assembler, JSGeneratorObject::ResumeMode resume_mode,
17 char const* const method_name) {
18 typedef CodeStubAssembler::Label Label;
19 typedef compiler::Node Node;
20
21 Node* receiver = assembler->Parameter(0);
22 Node* value = assembler->Parameter(1);
23 Node* context = assembler->Parameter(4);
24 Node* closed =
25 assembler->SmiConstant(Smi::FromInt(JSGeneratorObject::kGeneratorClosed));
26
27 // Check if the {receiver} is actually a JSGeneratorObject.
28 Label if_receiverisincompatible(assembler, Label::kDeferred);
29 assembler->GotoIf(assembler->TaggedIsSmi(receiver),
30 &if_receiverisincompatible);
31 Node* receiver_instance_type = assembler->LoadInstanceType(receiver);
32 assembler->GotoUnless(assembler->Word32Equal(
33 receiver_instance_type,
34 assembler->Int32Constant(JS_GENERATOR_OBJECT_TYPE)),
35 &if_receiverisincompatible);
36
37 // Check if the {receiver} is running or already closed.
38 Node* receiver_continuation = assembler->LoadObjectField(
39 receiver, JSGeneratorObject::kContinuationOffset);
40 Label if_receiverisclosed(assembler, Label::kDeferred),
41 if_receiverisrunning(assembler, Label::kDeferred);
42 assembler->GotoIf(assembler->SmiEqual(receiver_continuation, closed),
43 &if_receiverisclosed);
44 DCHECK_LT(JSGeneratorObject::kGeneratorExecuting,
45 JSGeneratorObject::kGeneratorClosed);
46 assembler->GotoIf(assembler->SmiLessThan(receiver_continuation, closed),
47 &if_receiverisrunning);
48
49 // Resume the {receiver} using our trampoline.
50 Node* result = assembler->CallStub(
51 CodeFactory::ResumeGenerator(assembler->isolate()), context, value,
52 receiver, assembler->SmiConstant(Smi::FromInt(resume_mode)));
53 assembler->Return(result);
54
55 assembler->Bind(&if_receiverisincompatible);
56 {
57 // The {receiver} is not a valid JSGeneratorObject.
58 Node* result = assembler->CallRuntime(
59 Runtime::kThrowIncompatibleMethodReceiver, context,
60 assembler->HeapConstant(assembler->factory()->NewStringFromAsciiChecked(
61 method_name, TENURED)),
62 receiver);
63 assembler->Return(result); // Never reached.
64 }
65
66 assembler->Bind(&if_receiverisclosed);
67 {
68 // The {receiver} is closed already.
69 Node* result = nullptr;
70 switch (resume_mode) {
71 case JSGeneratorObject::kNext:
72 result = assembler->CallRuntime(Runtime::kCreateIterResultObject,
73 context, assembler->UndefinedConstant(),
74 assembler->BooleanConstant(true));
75 break;
76 case JSGeneratorObject::kReturn:
77 result =
78 assembler->CallRuntime(Runtime::kCreateIterResultObject, context,
79 value, assembler->BooleanConstant(true));
80 break;
81 case JSGeneratorObject::kThrow:
82 result = assembler->CallRuntime(Runtime::kThrow, context, value);
83 break;
84 }
85 assembler->Return(result);
86 }
87
88 assembler->Bind(&if_receiverisrunning);
89 {
90 Node* result =
91 assembler->CallRuntime(Runtime::kThrowGeneratorRunning, context);
92 assembler->Return(result); // Never reached.
93 }
94 }
95
96 } // anonymous namespace
97
98 // ES6 section 25.3.1.2 Generator.prototype.next ( value )
Generate_GeneratorPrototypeNext(CodeStubAssembler * assembler)99 void Builtins::Generate_GeneratorPrototypeNext(CodeStubAssembler* assembler) {
100 Generate_GeneratorPrototypeResume(assembler, JSGeneratorObject::kNext,
101 "[Generator].prototype.next");
102 }
103
104 // ES6 section 25.3.1.3 Generator.prototype.return ( value )
Generate_GeneratorPrototypeReturn(CodeStubAssembler * assembler)105 void Builtins::Generate_GeneratorPrototypeReturn(CodeStubAssembler* assembler) {
106 Generate_GeneratorPrototypeResume(assembler, JSGeneratorObject::kReturn,
107 "[Generator].prototype.return");
108 }
109
110 // ES6 section 25.3.1.4 Generator.prototype.throw ( exception )
Generate_GeneratorPrototypeThrow(CodeStubAssembler * assembler)111 void Builtins::Generate_GeneratorPrototypeThrow(CodeStubAssembler* assembler) {
112 Generate_GeneratorPrototypeResume(assembler, JSGeneratorObject::kThrow,
113 "[Generator].prototype.throw");
114 }
115
116 } // namespace internal
117 } // namespace v8
118