dfg/DFGUnificationPhase.cpp

   1 /*
   2  * Copyright (C) 2013 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 "DFGUnificationPhase.h"
  28
  29 #if ENABLE(DFG_JIT)
  30
  31 #include "DFGBasicBlockInlines.h"
  32 #include "DFGGraph.h"
  33 #include "DFGPhase.h"
  34 #include "Operations.h"
  35
  36 namespace JSC { namespace DFG {
  37
  38 class UnificationPhase : public Phase {
  39 public:
  40     UnificationPhase(Graph& graph)
  41         : Phase(graph, "unification")
  42     {
  43     }
  44
  45     bool run()
  46     {
  47         ASSERT(m_graph.m_form == ThreadedCPS);
  48         ASSERT(m_graph.m_unificationState == LocallyUnified);
  49
  50         // Ensure that all Phi functions are unified.
  51         for (BlockIndex blockIndex = m_graph.m_blocks.size(); blockIndex--;) {
  52             BasicBlock* block = m_graph.m_blocks[blockIndex].get();
  53             if (!block)
  54                 continue;
  55             ASSERT(block->isReachable);
  56
  57             for (unsigned phiIndex = block->phis.size(); phiIndex--;) {
  58                 Node* phi = block->phis[phiIndex];
  59                 for (unsigned childIdx = 0; childIdx < AdjacencyList::Size; ++childIdx) {
  60                     if (!phi->children.child(childIdx))
  61                         break;
  62
  63                     phi->variableAccessData()->unify(
  64                         phi->children.child(childIdx)->variableAccessData());
  65                 }
  66             }
  67         }
  68
  69         // Ensure that all predictions are fixed up based on the unification.
  70         for (unsigned i = 0; i < m_graph.m_variableAccessData.size(); ++i) {
  71             VariableAccessData* data = &m_graph.m_variableAccessData[i];
  72             data->find()->predict(data->nonUnifiedPrediction());
  73             data->find()->mergeIsCaptured(data->isCaptured());
  74             data->find()->mergeStructureCheckHoistingFailed(data->structureCheckHoistingFailed());
  75             data->find()->mergeShouldNeverUnbox(data->shouldNeverUnbox());
  76             data->find()->mergeIsLoadedFrom(data->isLoadedFrom());
  77         }
  78
  79         m_graph.m_unificationState = GloballyUnified;
  80         return true;
  81     }
  82 };
  83
  84 bool performUnification(Graph& graph)
  85 {
  86     SamplingRegion samplingRegion("DFG Unification Phase");
  87     return runPhase<UnificationPhase>(graph);
  88 }
  89
  90 } } // namespace JSC::DFG
  91
  92 #endif // ENABLE(DFG_JIT)
  93