1 // Copyright 2013 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_HYDROGEN_ESCAPE_ANALYSIS_H_
6 #define V8_HYDROGEN_ESCAPE_ANALYSIS_H_
7 
8 #include "src/allocation.h"
9 #include "src/hydrogen.h"
10 
11 namespace v8 {
12 namespace internal {
13 
14 
15 class HEscapeAnalysisPhase : public HPhase {
16  public:
HEscapeAnalysisPhase(HGraph * graph)17   explicit HEscapeAnalysisPhase(HGraph* graph)
18       : HPhase("H_Escape analysis", graph),
19         captured_(0, zone()),
20         number_of_objects_(0),
21         number_of_values_(0),
22         cumulative_values_(0),
23         block_states_(graph->blocks()->length(), zone()) { }
24 
25   void Run();
26 
27  private:
28   void CollectCapturedValues();
29   bool HasNoEscapingUses(HValue* value, int size);
30   void PerformScalarReplacement();
31   void AnalyzeDataFlow(HInstruction* instr);
32 
33   HCapturedObject* NewState(HInstruction* prev);
34   HCapturedObject* NewStateForAllocation(HInstruction* prev);
35   HCapturedObject* NewStateForLoopHeader(HInstruction* prev, HCapturedObject*);
36   HCapturedObject* NewStateCopy(HInstruction* prev, HCapturedObject* state);
37 
38   HPhi* NewPhiAndInsert(HBasicBlock* block, HValue* incoming_value, int index);
39 
40   HValue* NewMapCheckAndInsert(HCapturedObject* state, HCheckMaps* mapcheck);
41 
42   HValue* NewLoadReplacement(HLoadNamedField* load, HValue* load_value);
43 
StateAt(HBasicBlock * block)44   HCapturedObject* StateAt(HBasicBlock* block) {
45     return block_states_.at(block->block_id());
46   }
47 
SetStateAt(HBasicBlock * block,HCapturedObject * state)48   void SetStateAt(HBasicBlock* block, HCapturedObject* state) {
49     block_states_.Set(block->block_id(), state);
50   }
51 
52   // List of allocations captured during collection phase.
53   ZoneList<HInstruction*> captured_;
54 
55   // Number of captured objects on which scalar replacement was done.
56   int number_of_objects_;
57 
58   // Number of scalar values tracked during scalar replacement phase.
59   int number_of_values_;
60   int cumulative_values_;
61 
62   // Map of block IDs to the data-flow state at block entry during the
63   // scalar replacement phase.
64   ZoneList<HCapturedObject*> block_states_;
65 };
66 
67 
68 } }  // namespace v8::internal
69 
70 #endif  // V8_HYDROGEN_ESCAPE_ANALYSIS_H_
71