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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 #ifndef V8_COMPILER_FRAME_STATES_H_
6 #define V8_COMPILER_FRAME_STATES_H_
7 
8 #include "src/handles.h"
9 #include "src/utils.h"
10 
11 namespace v8 {
12 namespace internal {
13 
14 // Forward declarations.
15 class SharedFunctionInfo;
16 
17 namespace compiler {
18 
19 // Flag that describes how to combine the current environment with
20 // the output of a node to obtain a framestate for lazy bailout.
21 class OutputFrameStateCombine {
22  public:
23   enum Kind {
24     kPushOutput,  // Push the output on the expression stack.
25     kPokeAt       // Poke at the given environment location,
26                   // counting from the top of the stack.
27   };
28 
Ignore()29   static OutputFrameStateCombine Ignore() {
30     return OutputFrameStateCombine(kPushOutput, 0);
31   }
32   static OutputFrameStateCombine Push(size_t count = 1) {
33     return OutputFrameStateCombine(kPushOutput, count);
34   }
PokeAt(size_t index)35   static OutputFrameStateCombine PokeAt(size_t index) {
36     return OutputFrameStateCombine(kPokeAt, index);
37   }
38 
kind()39   Kind kind() const { return kind_; }
GetPushCount()40   size_t GetPushCount() const {
41     DCHECK_EQ(kPushOutput, kind());
42     return parameter_;
43   }
GetOffsetToPokeAt()44   size_t GetOffsetToPokeAt() const {
45     DCHECK_EQ(kPokeAt, kind());
46     return parameter_;
47   }
48 
IsOutputIgnored()49   bool IsOutputIgnored() const {
50     return kind_ == kPushOutput && parameter_ == 0;
51   }
52 
ConsumedOutputCount()53   size_t ConsumedOutputCount() const {
54     return kind_ == kPushOutput ? GetPushCount() : 1;
55   }
56 
57   bool operator==(OutputFrameStateCombine const& other) const {
58     return kind_ == other.kind_ && parameter_ == other.parameter_;
59   }
60   bool operator!=(OutputFrameStateCombine const& other) const {
61     return !(*this == other);
62   }
63 
64   friend size_t hash_value(OutputFrameStateCombine const&);
65   friend std::ostream& operator<<(std::ostream&,
66                                   OutputFrameStateCombine const&);
67 
68  private:
OutputFrameStateCombine(Kind kind,size_t parameter)69   OutputFrameStateCombine(Kind kind, size_t parameter)
70       : kind_(kind), parameter_(parameter) {}
71 
72   Kind const kind_;
73   size_t const parameter_;
74 };
75 
76 
77 // The type of stack frame that a FrameState node represents.
78 enum class FrameStateType {
79   kJavaScriptFunction,   // Represents an unoptimized JavaScriptFrame.
80   kInterpretedFunction,  // Represents an InterpretedFrame.
81   kArgumentsAdaptor,     // Represents an ArgumentsAdaptorFrame.
82   kTailCallerFunction,   // Represents a frame removed by tail call elimination.
83   kConstructStub         // Represents a ConstructStubFrame.
84 };
85 
86 class FrameStateFunctionInfo {
87  public:
FrameStateFunctionInfo(FrameStateType type,int parameter_count,int local_count,Handle<SharedFunctionInfo> shared_info)88   FrameStateFunctionInfo(FrameStateType type, int parameter_count,
89                          int local_count,
90                          Handle<SharedFunctionInfo> shared_info)
91       : type_(type),
92         parameter_count_(parameter_count),
93         local_count_(local_count),
94         shared_info_(shared_info) {}
95 
local_count()96   int local_count() const { return local_count_; }
parameter_count()97   int parameter_count() const { return parameter_count_; }
shared_info()98   Handle<SharedFunctionInfo> shared_info() const { return shared_info_; }
type()99   FrameStateType type() const { return type_; }
100 
IsJSFunctionType(FrameStateType type)101   static bool IsJSFunctionType(FrameStateType type) {
102     return type == FrameStateType::kJavaScriptFunction ||
103            type == FrameStateType::kInterpretedFunction;
104   }
105 
106  private:
107   FrameStateType const type_;
108   int const parameter_count_;
109   int const local_count_;
110   Handle<SharedFunctionInfo> const shared_info_;
111 };
112 
113 
114 class FrameStateInfo final {
115  public:
FrameStateInfo(BailoutId bailout_id,OutputFrameStateCombine state_combine,const FrameStateFunctionInfo * info)116   FrameStateInfo(BailoutId bailout_id, OutputFrameStateCombine state_combine,
117                  const FrameStateFunctionInfo* info)
118       : bailout_id_(bailout_id),
119         frame_state_combine_(state_combine),
120         info_(info) {}
121 
type()122   FrameStateType type() const {
123     return info_ == nullptr ? FrameStateType::kJavaScriptFunction
124                             : info_->type();
125   }
bailout_id()126   BailoutId bailout_id() const { return bailout_id_; }
state_combine()127   OutputFrameStateCombine state_combine() const { return frame_state_combine_; }
shared_info()128   MaybeHandle<SharedFunctionInfo> shared_info() const {
129     return info_ == nullptr ? MaybeHandle<SharedFunctionInfo>()
130                             : info_->shared_info();
131   }
parameter_count()132   int parameter_count() const {
133     return info_ == nullptr ? 0 : info_->parameter_count();
134   }
local_count()135   int local_count() const {
136     return info_ == nullptr ? 0 : info_->local_count();
137   }
function_info()138   const FrameStateFunctionInfo* function_info() const { return info_; }
139 
140  private:
141   BailoutId const bailout_id_;
142   OutputFrameStateCombine const frame_state_combine_;
143   const FrameStateFunctionInfo* const info_;
144 };
145 
146 bool operator==(FrameStateInfo const&, FrameStateInfo const&);
147 bool operator!=(FrameStateInfo const&, FrameStateInfo const&);
148 
149 size_t hash_value(FrameStateInfo const&);
150 
151 std::ostream& operator<<(std::ostream&, FrameStateInfo const&);
152 
153 static const int kFrameStateParametersInput = 0;
154 static const int kFrameStateLocalsInput = 1;
155 static const int kFrameStateStackInput = 2;
156 static const int kFrameStateContextInput = 3;
157 static const int kFrameStateFunctionInput = 4;
158 static const int kFrameStateOuterStateInput = 5;
159 static const int kFrameStateInputCount = kFrameStateOuterStateInput + 1;
160 
161 }  // namespace compiler
162 }  // namespace internal
163 }  // namespace v8
164 
165 #endif  // V8_COMPILER_FRAME_STATES_H_
166