JavaScriptCore/bytecode/Instruction.h

   1 /*
   2  * Copyright (C) 2008 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  *
   8  * 1.  Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  * 2.  Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  14  *     its contributors may be used to endorse or promote products derived
  15  *     from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #ifndef Instruction_h
  30 #define Instruction_h
  31
  32 #include "MacroAssembler.h"
  33 #include "Opcode.h"
  34 #include "Structure.h"
  35 #include <wtf/VectorTraits.h>
  36
  37 #define POLYMORPHIC_LIST_CACHE_SIZE 8
  38
  39 namespace JSC {
  40
  41     // *Sigh*, If the JIT is enabled we need to track the stubRountine (of type CodeLocationLabel),
  42     // 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
  43     // curently actually use PolymorphicAccessStructureLists, which we should).  Anyway, this seems like the best
  44     // solution for now - will need to something smarter if/when we actually want mixed-mode operation.
  45 #if ENABLE(JIT)
  46     typedef CodeLocationLabel PolymorphicAccessStructureListStubRoutineType;
  47 #else
  48     typedef void* PolymorphicAccessStructureListStubRoutineType;
  49 #endif
  50
  51     class JSCell;
  52     class Structure;
  53     class StructureChain;
  54
  55     // 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.
  56     struct PolymorphicAccessStructureList : FastAllocBase {
  57         struct PolymorphicStubInfo {
  58             bool isChain;
  59             PolymorphicAccessStructureListStubRoutineType stubRoutine;
  60             Structure* base;
  61             union {
  62                 Structure* proto;
  63                 StructureChain* chain;
  64             } u;
  65
  66             void set(PolymorphicAccessStructureListStubRoutineType _stubRoutine, Structure* _base)
  67             {
  68                 stubRoutine = _stubRoutine;
  69                 base = _base;
  70                 u.proto = 0;
  71                 isChain = false;
  72             }
  73
  74             void set(PolymorphicAccessStructureListStubRoutineType _stubRoutine, Structure* _base, Structure* _proto)
  75             {
  76                 stubRoutine = _stubRoutine;
  77                 base = _base;
  78                 u.proto = _proto;
  79                 isChain = false;
  80             }
  81
  82             void set(PolymorphicAccessStructureListStubRoutineType _stubRoutine, Structure* _base, StructureChain* _chain)
  83             {
  84                 stubRoutine = _stubRoutine;
  85                 base = _base;
  86                 u.chain = _chain;
  87                 isChain = true;
  88             }
  89         } list[POLYMORPHIC_LIST_CACHE_SIZE];
  90
  91         PolymorphicAccessStructureList(PolymorphicAccessStructureListStubRoutineType stubRoutine, Structure* firstBase)
  92         {
  93             list[0].set(stubRoutine, firstBase);
  94         }
  95
  96         PolymorphicAccessStructureList(PolymorphicAccessStructureListStubRoutineType stubRoutine, Structure* firstBase, Structure* firstProto)
  97         {
  98             list[0].set(stubRoutine, firstBase, firstProto);
  99         }
 100
 101         PolymorphicAccessStructureList(PolymorphicAccessStructureListStubRoutineType stubRoutine, Structure* firstBase, StructureChain* firstChain)
 102         {
 103             list[0].set(stubRoutine, firstBase, firstChain);
 104         }
 105
 106         void derefStructures(int count)
 107         {
 108             for (int i = 0; i < count; ++i) {
 109                 PolymorphicStubInfo& info = list[i];
 110
 111                 ASSERT(info.base);
 112                 info.base->deref();
 113
 114                 if (info.u.proto) {
 115                     if (info.isChain)
 116                         info.u.chain->deref();
 117                     else
 118                         info.u.proto->deref();
 119                 }
 120             }
 121         }
 122     };
 123
 124     struct Instruction {
 125         Instruction(Opcode opcode)
 126         {
 127 #if !HAVE(COMPUTED_GOTO)
 128             // We have to initialize one of the pointer members to ensure that
 129             // the entire struct is initialized, when opcode is not a pointer.
 130             u.jsCell = 0;
 131 #endif
 132             u.opcode = opcode;
 133         }
 134
 135         Instruction(int operand)
 136         {
 137             // We have to initialize one of the pointer members to ensure that
 138             // the entire struct is initialized in 64-bit.
 139             u.jsCell = 0;
 140             u.operand = operand;
 141         }
 142
 143         Instruction(Structure* structure) { u.structure = structure; }
 144         Instruction(StructureChain* structureChain) { u.structureChain = structureChain; }
 145         Instruction(JSCell* jsCell) { u.jsCell = jsCell; }
 146         Instruction(PolymorphicAccessStructureList* polymorphicStructures) { u.polymorphicStructures = polymorphicStructures; }
 147
 148         union {
 149             Opcode opcode;
 150             int operand;
 151             Structure* structure;
 152             StructureChain* structureChain;
 153             JSCell* jsCell;
 154             PolymorphicAccessStructureList* polymorphicStructures;
 155         } u;
 156     };
 157
 158 } // namespace JSC
 159
 160 namespace WTF {
 161
 162     template<> struct VectorTraits<JSC::Instruction> : VectorTraitsBase<true, JSC::Instruction> { };
 163
 164 } // namespace WTF
 165
 166 #endif // Instruction_h