dfg/DFGCombinedLiveness.cpp

   1 /*
   2  * Copyright (C) 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 "DFGCombinedLiveness.h"
  28
  29 #if ENABLE(DFG_JIT)
  30
  31 #include "DFGAvailabilityMap.h"
  32 #include "DFGBlockMapInlines.h"
  33 #include "FullBytecodeLiveness.h"
  34 #include "JSCInlines.h"
  35
  36 namespace JSC { namespace DFG {
  37
  38 HashSet<Node*> liveNodesAtHead(Graph& graph, BasicBlock* block)
  39 {
  40     HashSet<Node*> seen;
  41     for (Node* node : block->ssa->liveAtHead)
  42         seen.add(node);
  43
  44     AvailabilityMap& availabilityMap = block->ssa->availabilityAtHead;
  45     graph.forAllLocalsLiveInBytecode(
  46         block->firstOrigin().forExit,
  47         [&] (VirtualRegister reg) {
  48             availabilityMap.closeStartingWithLocal(
  49                 reg,
  50                 [&] (Node* node) -> bool {
  51                     return seen.contains(node);
  52                 },
  53                 [&] (Node* node) -> bool {
  54                     return seen.add(node).isNewEntry;
  55                 });
  56         });
  57
  58     return seen;
  59 }
  60
  61 CombinedLiveness::CombinedLiveness(Graph& graph)
  62     : liveAtHead(graph)
  63     , liveAtTail(graph)
  64 {
  65     // First compute the liveAtHead for each block.
  66     for (BasicBlock* block : graph.blocksInNaturalOrder())
  67         liveAtHead[block] = liveNodesAtHead(graph, block);
  68
  69     // Now compute the liveAtTail by unifying the liveAtHead of the successors.
  70     for (BasicBlock* block : graph.blocksInNaturalOrder()) {
  71         for (BasicBlock* successor : block->successors()) {
  72             for (Node* node : liveAtHead[successor])
  73                 liveAtTail[block].add(node);
  74         }
  75     }
  76 }
  77
  78 } } // namespace JSC::DFG
  79
  80 #endif // ENABLE(DFG_JIT)
  81