dfg/DFGSSALoweringPhase.cpp

   1 /*
   2  * Copyright (C) 2013, 2014 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 "DFGSSALoweringPhase.h"
  28
  29 #if ENABLE(DFG_JIT)
  30
  31 #include "DFGBasicBlockInlines.h"
  32 #include "DFGGraph.h"
  33 #include "DFGInsertionSet.h"
  34 #include "DFGPhase.h"
  35 #include "JSCInlines.h"
  36
  37 namespace JSC { namespace DFG {
  38
  39 class SSALoweringPhase : public Phase {
  40     static const bool verbose = false;
  41
  42 public:
  43     SSALoweringPhase(Graph& graph)
  44         : Phase(graph, "SSA lowering")
  45         , m_insertionSet(graph)
  46     {
  47     }
  48
  49     bool run()
  50     {
  51         RELEASE_ASSERT(m_graph.m_form == SSA);
  52
  53         for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) {
  54             m_block = m_graph.block(blockIndex);
  55             if (!m_block)
  56                 continue;
  57             for (m_nodeIndex = 0; m_nodeIndex < m_block->size(); ++m_nodeIndex) {
  58                 m_node = m_block->at(m_nodeIndex);
  59                 handleNode();
  60             }
  61             m_insertionSet.execute(m_block);
  62         }
  63
  64         return true;
  65     }
  66
  67 private:
  68     void handleNode()
  69     {
  70         switch (m_node->op()) {
  71         case GetByVal:
  72         case HasIndexedProperty:
  73             lowerBoundsCheck(m_node->child1(), m_node->child2(), m_node->child3());
  74             break;
  75
  76         case PutByVal:
  77         case PutByValDirect: {
  78             Edge base = m_graph.varArgChild(m_node, 0);
  79             Edge index = m_graph.varArgChild(m_node, 1);
  80             Edge storage = m_graph.varArgChild(m_node, 3);
  81             if (lowerBoundsCheck(base, index, storage))
  82                 break;
  83
  84             if (m_node->arrayMode().typedArrayType() != NotTypedArray && m_node->arrayMode().isOutOfBounds()) {
  85                 Node* length = m_insertionSet.insertNode(
  86                     m_nodeIndex, SpecInt32, GetArrayLength, m_node->origin,
  87                     OpInfo(m_node->arrayMode().asWord()), base, storage);
  88
  89                 m_graph.varArgChild(m_node, 4) = Edge(length, KnownInt32Use);
  90                 break;
  91             }
  92             break;
  93         }
  94
  95         default:
  96             break;
  97         }
  98     }
  99
 100     bool lowerBoundsCheck(Edge base, Edge index, Edge storage)
 101     {
 102         if (!m_node->arrayMode().permitsBoundsCheckLowering())
 103             return false;
 104
 105         if (!m_node->arrayMode().lengthNeedsStorage())
 106             storage = Edge();
 107
 108         Node* length = m_insertionSet.insertNode(
 109             m_nodeIndex, SpecInt32, GetArrayLength, m_node->origin,
 110             OpInfo(m_node->arrayMode().asWord()), base, storage);
 111         m_insertionSet.insertNode(
 112             m_nodeIndex, SpecInt32, CheckInBounds, m_node->origin,
 113             index, Edge(length, KnownInt32Use));
 114         return true;
 115     }
 116
 117     InsertionSet m_insertionSet;
 118     BasicBlock* m_block;
 119     unsigned m_nodeIndex;
 120     Node* m_node;
 121 };
 122
 123 bool performSSALowering(Graph& graph)
 124 {
 125     SamplingRegion samplingRegion("DFG SSA Lowering Phase");
 126     return runPhase<SSALoweringPhase>(graph);
 127 }
 128
 129 } } // namespace JSC::DFG
 130
 131 #endif // ENABLE(DFG_JIT)
 132