bytecode/PolymorphicAccessStructureList.h

   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 #ifndef PolymorphicAccessStructureList_h
  27 #define PolymorphicAccessStructureList_h
  28
  29 #include "JITStubRoutine.h"
  30 #include "Structure.h"
  31 #include "StructureChain.h"
  32 #include <wtf/Platform.h>
  33
  34 #define POLYMORPHIC_LIST_CACHE_SIZE 8
  35
  36 namespace JSC {
  37
  38 // *Sigh*, If the JIT is enabled we need to track the stubRountine (of type CodeLocationLabel),
  39 // If the JIT is not in use we don't actually need the variable (that said, if the JIT is not in use we don't
  40 // curently actually use PolymorphicAccessStructureLists, which we should).  Anyway, this seems like the best
  41 // solution for now - will need to something smarter if/when we actually want mixed-mode operation.
  42
  43 #if ENABLE(JIT)
  44 // Structure used by op_get_by_id_self_list and op_get_by_id_proto_list instruction to hold data off the main opcode stream.
  45 struct PolymorphicAccessStructureList {
  46     WTF_MAKE_FAST_ALLOCATED;
  47 public:
  48     struct PolymorphicStubInfo {
  49         bool isChain;
  50         bool isDirect;
  51         RefPtr<JITStubRoutine> stubRoutine;
  52         WriteBarrier<Structure> base;
  53         union {
  54             WriteBarrierBase<Structure> proto;
  55             WriteBarrierBase<StructureChain> chain;
  56         } u;
  57
  58         PolymorphicStubInfo()
  59         {
  60             u.proto.clear();
  61         }
  62
  63         void set(VM& vm, JSCell* owner, PassRefPtr<JITStubRoutine> _stubRoutine, Structure* _base, bool isDirect)
  64         {
  65             stubRoutine = _stubRoutine;
  66             base.set(vm, owner, _base);
  67             u.proto.clear();
  68             isChain = false;
  69             this->isDirect = isDirect;
  70         }
  71
  72         void set(VM& vm, JSCell* owner, PassRefPtr<JITStubRoutine> _stubRoutine, Structure* _base, Structure* _proto, bool isDirect)
  73         {
  74             stubRoutine = _stubRoutine;
  75             base.set(vm, owner, _base);
  76             u.proto.set(vm, owner, _proto);
  77             isChain = false;
  78             this->isDirect = isDirect;
  79         }
  80
  81         void set(VM& vm, JSCell* owner, PassRefPtr<JITStubRoutine> _stubRoutine, Structure* _base, StructureChain* _chain, bool isDirect)
  82         {
  83             stubRoutine = _stubRoutine;
  84             base.set(vm, owner, _base);
  85             u.chain.set(vm, owner, _chain);
  86             isChain = true;
  87             this->isDirect = isDirect;
  88         }
  89     } list[POLYMORPHIC_LIST_CACHE_SIZE];
  90
  91     PolymorphicAccessStructureList()
  92     {
  93     }
  94
  95     PolymorphicAccessStructureList(VM& vm, JSCell* owner, PassRefPtr<JITStubRoutine> stubRoutine, Structure* firstBase, bool isDirect)
  96     {
  97         list[0].set(vm, owner, stubRoutine, firstBase, isDirect);
  98     }
  99
 100     PolymorphicAccessStructureList(VM& vm, JSCell* owner, PassRefPtr<JITStubRoutine> stubRoutine, Structure* firstBase, Structure* firstProto, bool isDirect)
 101     {
 102         list[0].set(vm, owner, stubRoutine, firstBase, firstProto, isDirect);
 103     }
 104
 105     PolymorphicAccessStructureList(VM& vm, JSCell* owner, PassRefPtr<JITStubRoutine> stubRoutine, Structure* firstBase, StructureChain* firstChain, bool isDirect)
 106     {
 107         list[0].set(vm, owner, stubRoutine, firstBase, firstChain, isDirect);
 108     }
 109
 110     bool visitWeak(int count)
 111     {
 112         for (int i = 0; i < count; ++i) {
 113             PolymorphicStubInfo& info = list[i];
 114             if (!info.base) {
 115                 // We're being marked during initialisation of an entry
 116                 ASSERT(!info.u.proto);
 117                 continue;
 118             }
 119
 120             if (!Heap::isMarked(info.base.get()))
 121                 return false;
 122             if (info.u.proto && !info.isChain
 123                 && !Heap::isMarked(info.u.proto.get()))
 124                 return false;
 125             if (info.u.chain && info.isChain
 126                 && !Heap::isMarked(info.u.chain.get()))
 127                 return false;
 128         }
 129
 130         return true;
 131     }
 132 };
 133
 134 #endif // ENABLE(JIT)
 135
 136 } // namespace JSC
 137
 138 #endif // PolymorphicAccessStructureList_h
 139