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      1 // Copyright 2013 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 #ifndef V8_HYDROGEN_ESCAPE_ANALYSIS_H_
     29 #define V8_HYDROGEN_ESCAPE_ANALYSIS_H_
     30 
     31 #include "allocation.h"
     32 #include "hydrogen.h"
     33 
     34 namespace v8 {
     35 namespace internal {
     36 
     37 
     38 class HEscapeAnalysisPhase : public HPhase {
     39  public:
     40   explicit HEscapeAnalysisPhase(HGraph* graph)
     41       : HPhase("H_Escape analysis", graph),
     42         captured_(0, zone()),
     43         number_of_values_(0),
     44         cumulative_values_(0),
     45         block_states_(graph->blocks()->length(), zone()) { }
     46 
     47   void Run() {
     48     CollectCapturedValues();
     49     PerformScalarReplacement();
     50   }
     51 
     52  private:
     53   void CollectCapturedValues();
     54   void CollectIfNoEscapingUses(HInstruction* instr);
     55   void PerformScalarReplacement();
     56   void AnalyzeDataFlow(HInstruction* instr);
     57 
     58   HCapturedObject* NewState(HInstruction* prev);
     59   HCapturedObject* NewStateForAllocation(HInstruction* prev);
     60   HCapturedObject* NewStateForLoopHeader(HInstruction* prev, HCapturedObject*);
     61   HCapturedObject* NewStateCopy(HInstruction* prev, HCapturedObject* state);
     62 
     63   HPhi* NewPhiAndInsert(HBasicBlock* block, HValue* incoming_value, int index);
     64 
     65   HCapturedObject* StateAt(HBasicBlock* block) {
     66     return block_states_.at(block->block_id());
     67   }
     68 
     69   void SetStateAt(HBasicBlock* block, HCapturedObject* state) {
     70     block_states_.Set(block->block_id(), state);
     71   }
     72 
     73   // List of allocations captured during collection phase.
     74   ZoneList<HInstruction*> captured_;
     75 
     76   // Number of scalar values tracked during scalar replacement phase.
     77   int number_of_values_;
     78   int cumulative_values_;
     79 
     80   // Map of block IDs to the data-flow state at block entry during the
     81   // scalar replacement phase.
     82   ZoneList<HCapturedObject*> block_states_;
     83 };
     84 
     85 
     86 } }  // namespace v8::internal
     87 
     88 #endif  // V8_HYDROGEN_ESCAPE_ANALYSIS_H_
     89