dfg/DFGCleanUpPhase.cpp

   1 /*
   2  * Copyright (C) 2014, 2015 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 #include "config.h"
  27 #include "DFGCleanUpPhase.h"
  28
  29 #if ENABLE(DFG_JIT)
  30
  31 #include "DFGGraph.h"
  32 #include "DFGInsertionSet.h"
  33 #include "DFGPhase.h"
  34 #include "DFGPredictionPropagationPhase.h"
  35 #include "DFGVariableAccessDataDump.h"
  36 #include "JSCInlines.h"
  37
  38 namespace JSC { namespace DFG {
  39
  40 class CleanUpPhase : public Phase {
  41 public:
  42     CleanUpPhase(Graph& graph)
  43         : Phase(graph, "clean up")
  44     {
  45     }
  46
  47     bool run()
  48     {
  49         bool changed = false;
  50
  51         for (BasicBlock* block : m_graph.blocksInNaturalOrder()) {
  52             unsigned sourceIndex = 0;
  53             unsigned targetIndex = 0;
  54             while (sourceIndex < block->size()) {
  55                 Node* node = block->at(sourceIndex++);
  56                 bool kill = false;
  57
  58                 if (node->op() == Check)
  59                     node->children = node->children.justChecks();
  60
  61                 switch (node->op()) {
  62                 case Phantom:
  63                 case Check:
  64                     if (node->children.isEmpty())
  65                         kill = true;
  66                     break;
  67                 default:
  68                     break;
  69                 }
  70
  71                 if (kill)
  72                     m_graph.m_allocator.free(node);
  73                 else
  74                     block->at(targetIndex++) = node;
  75             }
  76             block->resize(targetIndex);
  77         }
  78
  79         return changed;
  80     }
  81 };
  82
  83 bool performCleanUp(Graph& graph)
  84 {
  85     SamplingRegion samplingRegion("DFG Clean Up Phase");
  86     return runPhase<CleanUpPhase>(graph);
  87 }
  88
  89 } } // namespace JSC::DFG
  90
  91 #endif // ENABLE(DFG_JIT)
  92