dfg/DFGDominators.h

   1 /*
   2  * Copyright (C) 2011 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef DFGDominators_h
  27 #define DFGDominators_h
  28
  29 #if ENABLE(DFG_JIT)
  30
  31 #include "DFGAnalysis.h"
  32 #include "DFGBasicBlock.h"
  33 #include "DFGCommon.h"
  34 #include <wtf/FastBitVector.h>
  35
  36 namespace JSC { namespace DFG {
  37
  38 class Graph;
  39
  40 class Dominators : public Analysis<Dominators> {
  41 public:
  42     Dominators();
  43     ~Dominators();
  44
  45     void compute(Graph&);
  46
  47     bool dominates(BlockIndex from, BlockIndex to) const
  48     {
  49         ASSERT(isValid());
  50         return m_results[to].get(from);
  51     }
  52
  53     bool dominates(BasicBlock* from, BasicBlock* to) const
  54     {
  55         return dominates(from->index, to->index);
  56     }
  57
  58     void dump(Graph&, PrintStream&) const;
  59
  60 private:
  61     bool pruneDominators(Graph&, BlockIndex);
  62
  63     Vector<FastBitVector> m_results; // For each block, the bitvector of blocks that dominate it.
  64     FastBitVector m_scratch; // A temporary bitvector with bit for each block. We recycle this to save new/deletes.
  65 };
  66
  67 } } // namespace JSC::DFG
  68
  69 #endif // ENABLE(DFG_JIT)
  70
  71 #endif // DFGDominators_h