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 "Opcode.h"
  33 #include "Structure.h"
  34 #include <wtf/VectorTraits.h>
  35
  36 #define POLYMORPHIC_LIST_CACHE_SIZE 4
  37
  38 namespace JSC {
  39
  40     class JSCell;
  41     class Structure;
  42     class StructureChain;
  43
  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         struct PolymorphicStubInfo {
  47             bool isChain;
  48             void* stubRoutine;
  49             Structure* base;
  50             union {
  51                 Structure* proto;
  52                 StructureChain* chain;
  53             } u;
  54
  55             void set(void* _stubRoutine, Structure* _base)
  56             {
  57                 stubRoutine = _stubRoutine;
  58                 base = _base;
  59                 u.proto = 0;
  60                 isChain = false;
  61             }
  62
  63             void set(void* _stubRoutine, Structure* _base, Structure* _proto)
  64             {
  65                 stubRoutine = _stubRoutine;
  66                 base = _base;
  67                 u.proto = _proto;
  68                 isChain = false;
  69             }
  70
  71             void set(void* _stubRoutine, Structure* _base, StructureChain* _chain)
  72             {
  73                 stubRoutine = _stubRoutine;
  74                 base = _base;
  75                 u.chain = _chain;
  76                 isChain = true;
  77             }
  78         } list[POLYMORPHIC_LIST_CACHE_SIZE];
  79
  80         PolymorphicAccessStructureList(void* stubRoutine, Structure* firstBase)
  81         {
  82             list[0].set(stubRoutine, firstBase);
  83         }
  84
  85         PolymorphicAccessStructureList(void* stubRoutine, Structure* firstBase, Structure* firstProto)
  86         {
  87             list[0].set(stubRoutine, firstBase, firstProto);
  88         }
  89
  90         PolymorphicAccessStructureList(void* stubRoutine, Structure* firstBase, StructureChain* firstChain)
  91         {
  92             list[0].set(stubRoutine, firstBase, firstChain);
  93         }
  94
  95         void derefStructures(int count)
  96         {
  97             for (int i = 0; i < count; ++i) {
  98                 PolymorphicStubInfo& info = list[i];
  99
 100                 ASSERT(info.base);
 101                 info.base->deref();
 102
 103                 if (info.u.proto) {
 104                     if (info.isChain)
 105                         info.u.chain->deref();
 106                     else
 107                         info.u.proto->deref();
 108                 }
 109             }
 110         }
 111     };
 112
 113     struct Instruction {
 114         Instruction(Opcode opcode)
 115         {
 116 #if !HAVE(COMPUTED_GOTO)
 117             // We have to initialize one of the pointer members to ensure that
 118             // the entire struct is initialized, when opcode is not a pointer.
 119             u.jsCell = 0;
 120 #endif
 121             u.opcode = opcode;
 122         }
 123
 124         Instruction(int operand)
 125         {
 126             // We have to initialize one of the pointer members to ensure that
 127             // the entire struct is initialized in 64-bit.
 128             u.jsCell = 0;
 129             u.operand = operand;
 130         }
 131
 132         Instruction(Structure* structure) { u.structure = structure; }
 133         Instruction(StructureChain* structureChain) { u.structureChain = structureChain; }
 134         Instruction(JSCell* jsCell) { u.jsCell = jsCell; }
 135         Instruction(PolymorphicAccessStructureList* polymorphicStructures) { u.polymorphicStructures = polymorphicStructures; }
 136
 137         union {
 138             Opcode opcode;
 139             int operand;
 140             Structure* structure;
 141             StructureChain* structureChain;
 142             JSCell* jsCell;
 143             PolymorphicAccessStructureList* polymorphicStructures;
 144         } u;
 145     };
 146
 147 } // namespace JSC
 148
 149 namespace WTF {
 150
 151     template<> struct VectorTraits<JSC::Instruction> : VectorTraitsBase<true, JSC::Instruction> { };
 152
 153 } // namespace WTF
 154
 155 #endif // Instruction_h