1 // Copyright 2015 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/compiler/js-frame-specialization.h"
6 
7 #include "src/compiler/js-graph.h"
8 #include "src/compiler/linkage.h"
9 #include "src/frames-inl.h"
10 
11 namespace v8 {
12 namespace internal {
13 namespace compiler {
14 
Reduce(Node * node)15 Reduction JSFrameSpecialization::Reduce(Node* node) {
16   switch (node->opcode()) {
17     case IrOpcode::kOsrValue:
18       return ReduceOsrValue(node);
19     case IrOpcode::kParameter:
20       return ReduceParameter(node);
21     default:
22       break;
23   }
24   return NoChange();
25 }
26 
27 
ReduceOsrValue(Node * node)28 Reduction JSFrameSpecialization::ReduceOsrValue(Node* node) {
29   DCHECK_EQ(IrOpcode::kOsrValue, node->opcode());
30   Handle<Object> value;
31   int const index = OpParameter<int>(node);
32   int const parameters_count = frame()->ComputeParametersCount() + 1;
33   if (index == Linkage::kOsrContextSpillSlotIndex) {
34     value = handle(frame()->context(), isolate());
35   } else if (index >= parameters_count) {
36     value = handle(frame()->GetExpression(index - parameters_count), isolate());
37   } else {
38     // The OsrValue index 0 is the receiver.
39     value =
40         handle(index ? frame()->GetParameter(index - 1) : frame()->receiver(),
41                isolate());
42   }
43   return Replace(jsgraph()->Constant(value));
44 }
45 
46 
ReduceParameter(Node * node)47 Reduction JSFrameSpecialization::ReduceParameter(Node* node) {
48   DCHECK_EQ(IrOpcode::kParameter, node->opcode());
49   Handle<Object> value;
50   int const index = ParameterIndexOf(node->op());
51   int const parameters_count = frame()->ComputeParametersCount() + 1;
52   if (index == Linkage::kJSCallClosureParamIndex) {
53     // The Parameter index references the closure.
54     value = handle(frame()->function(), isolate());
55   } else if (index == Linkage::GetJSCallArgCountParamIndex(parameters_count)) {
56     // The Parameter index references the parameter count.
57     value = handle(Smi::FromInt(parameters_count - 1), isolate());
58   } else if (index == Linkage::GetJSCallContextParamIndex(parameters_count)) {
59     // The Parameter index references the context.
60     value = handle(frame()->context(), isolate());
61   } else {
62     // The Parameter index 0 is the receiver.
63     value =
64         handle(index ? frame()->GetParameter(index - 1) : frame()->receiver(),
65                isolate());
66   }
67   return Replace(jsgraph()->Constant(value));
68 }
69 
70 
isolate() const71 Isolate* JSFrameSpecialization::isolate() const { return jsgraph()->isolate(); }
72 
73 }  // namespace compiler
74 }  // namespace internal
75 }  // namespace v8
76