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      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:
     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 
     44   HCapturedObject* StateAt(HBasicBlock* block) {
     45     return block_states_.at(block->block_id());
     46   }
     47 
     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