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 #include <wtf/Platform.h>
  30
  31 #if ENABLE(DFG_JIT)
  32
  33 #include "DFGCommon.h"
  34 #include <wtf/FastBitVector.h>
  35
  36 namespace JSC { namespace DFG {
  37
  38 class Graph;
  39
  40 class Dominators {
  41 public:
  42     Dominators();
  43     ~Dominators();
  44
  45     void compute(Graph& graph);
  46     void invalidate()
  47     {
  48         m_valid = false;
  49     }
  50     void computeIfNecessary(Graph& graph)
  51     {
  52         if (m_valid)
  53             return;
  54         compute(graph);
  55     }
  56
  57     bool isValid() const { return m_valid; }
  58
  59     bool dominates(BlockIndex from, BlockIndex to) const
  60     {
  61         ASSERT(isValid());
  62         return m_results[to].get(from);
  63     }
  64
  65 private:
  66     bool iterateForBlock(Graph& graph, BlockIndex);
  67
  68     Vector<FastBitVector> m_results;
  69     FastBitVector m_scratch;
  70     bool m_valid;
  71 };
  72
  73 } } // namespace JSC::DFG
  74
  75 #endif // ENABLE(DFG_JIT)
  76
  77 #endif // DFGDominators_h