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
11namespace v8 {
12namespace internal {
13namespace compiler {
14
15Reduction JSFrameSpecialization::Reduce(Node* node) {
16  switch (node->opcode()) {
17    case IrOpcode::kOsrValue:
18      return ReduceOsrValue(node);
19    case IrOpcode::kOsrGuard:
20      return ReduceOsrGuard(node);
21    case IrOpcode::kParameter:
22      return ReduceParameter(node);
23    default:
24      break;
25  }
26  return NoChange();
27}
28
29Reduction JSFrameSpecialization::ReduceOsrValue(Node* node) {
30  // JSFrameSpecialization should never run on interpreted frames, since the
31  // code below assumes standard stack frame layouts.
32  DCHECK(!frame()->is_interpreted());
33  DCHECK_EQ(IrOpcode::kOsrValue, node->opcode());
34  Handle<Object> value;
35  int index = OsrValueIndexOf(node->op());
36  int const parameters_count = frame()->ComputeParametersCount() + 1;
37  if (index == Linkage::kOsrContextSpillSlotIndex) {
38    value = handle(frame()->context(), isolate());
39  } else if (index >= parameters_count) {
40    value = handle(frame()->GetExpression(index - parameters_count), isolate());
41  } else {
42    // The OsrValue index 0 is the receiver.
43    value =
44        handle(index ? frame()->GetParameter(index - 1) : frame()->receiver(),
45               isolate());
46  }
47  return Replace(jsgraph()->Constant(value));
48}
49
50Reduction JSFrameSpecialization::ReduceOsrGuard(Node* node) {
51  DCHECK_EQ(IrOpcode::kOsrGuard, node->opcode());
52  ReplaceWithValue(node, node->InputAt(0),
53                   NodeProperties::GetEffectInput(node));
54  return Changed(node);
55}
56
57Reduction JSFrameSpecialization::ReduceParameter(Node* node) {
58  DCHECK_EQ(IrOpcode::kParameter, node->opcode());
59  Handle<Object> value;
60  int const index = ParameterIndexOf(node->op());
61  int const parameters_count = frame()->ComputeParametersCount() + 1;
62  if (index == Linkage::kJSCallClosureParamIndex) {
63    // The Parameter index references the closure.
64    value = handle(frame()->function(), isolate());
65  } else if (index == Linkage::GetJSCallArgCountParamIndex(parameters_count)) {
66    // The Parameter index references the parameter count.
67    value = handle(Smi::FromInt(parameters_count - 1), isolate());
68  } else if (index == Linkage::GetJSCallContextParamIndex(parameters_count)) {
69    // The Parameter index references the context.
70    value = handle(frame()->context(), isolate());
71  } else {
72    // The Parameter index 0 is the receiver.
73    value =
74        handle(index ? frame()->GetParameter(index - 1) : frame()->receiver(),
75               isolate());
76  }
77  return Replace(jsgraph()->Constant(value));
78}
79
80
81Isolate* JSFrameSpecialization::isolate() const { return jsgraph()->isolate(); }
82
83}  // namespace compiler
84}  // namespace internal
85}  // namespace v8
86