assembler/RepatchBuffer.h

   1 /*
   2  * Copyright (C) 2009 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 RepatchBuffer_h
  27 #define RepatchBuffer_h
  28
  29 #if ENABLE(JIT)
  30
  31 #include "CodeBlock.h"
  32 #include <MacroAssembler.h>
  33 #include <wtf/Noncopyable.h>
  34
  35 namespace JSC {
  36
  37 // RepatchBuffer:
  38 //
  39 // This class is used to modify code after code generation has been completed,
  40 // and after the code has potentially already been executed.  This mechanism is
  41 // used to apply optimizations to the code.
  42 //
  43 class RepatchBuffer {
  44     typedef MacroAssemblerCodePtr CodePtr;
  45
  46 public:
  47     RepatchBuffer(CodeBlock* codeBlock)
  48     {
  49         JITCode& code = codeBlock->getJITCode();
  50         m_start = code.start();
  51         m_size = code.size();
  52
  53         ExecutableAllocator::makeWritable(m_start, m_size);
  54     }
  55
  56     ~RepatchBuffer()
  57     {
  58         ExecutableAllocator::makeExecutable(m_start, m_size);
  59     }
  60
  61     void relink(CodeLocationJump jump, CodeLocationLabel destination)
  62     {
  63         MacroAssembler::repatchJump(jump, destination);
  64     }
  65
  66     void relink(CodeLocationCall call, CodeLocationLabel destination)
  67     {
  68         MacroAssembler::repatchCall(call, destination);
  69     }
  70
  71     void relink(CodeLocationCall call, FunctionPtr destination)
  72     {
  73         MacroAssembler::repatchCall(call, destination);
  74     }
  75
  76     void relink(CodeLocationNearCall nearCall, CodePtr destination)
  77     {
  78         MacroAssembler::repatchNearCall(nearCall, CodeLocationLabel(destination));
  79     }
  80
  81     void relink(CodeLocationNearCall nearCall, CodeLocationLabel destination)
  82     {
  83         MacroAssembler::repatchNearCall(nearCall, destination);
  84     }
  85
  86     void repatch(CodeLocationDataLabel32 dataLabel32, int32_t value)
  87     {
  88         MacroAssembler::repatchInt32(dataLabel32, value);
  89     }
  90
  91     void repatch(CodeLocationDataLabelCompact dataLabelCompact, int32_t value)
  92     {
  93         MacroAssembler::repatchCompact(dataLabelCompact, value);
  94     }
  95
  96     void repatch(CodeLocationDataLabelPtr dataLabelPtr, void* value)
  97     {
  98         MacroAssembler::repatchPointer(dataLabelPtr, value);
  99     }
 100
 101     void relinkCallerToTrampoline(ReturnAddressPtr returnAddress, CodeLocationLabel label)
 102     {
 103         relink(CodeLocationCall(CodePtr(returnAddress)), label);
 104     }
 105
 106     void relinkCallerToTrampoline(ReturnAddressPtr returnAddress, CodePtr newCalleeFunction)
 107     {
 108         relinkCallerToTrampoline(returnAddress, CodeLocationLabel(newCalleeFunction));
 109     }
 110
 111     void relinkCallerToFunction(ReturnAddressPtr returnAddress, FunctionPtr function)
 112     {
 113         relink(CodeLocationCall(CodePtr(returnAddress)), function);
 114     }
 115
 116     void relinkNearCallerToTrampoline(ReturnAddressPtr returnAddress, CodeLocationLabel label)
 117     {
 118         relink(CodeLocationNearCall(CodePtr(returnAddress)), label);
 119     }
 120
 121     void relinkNearCallerToTrampoline(ReturnAddressPtr returnAddress, CodePtr newCalleeFunction)
 122     {
 123         relinkNearCallerToTrampoline(returnAddress, CodeLocationLabel(newCalleeFunction));
 124     }
 125
 126     void replaceWithLoad(CodeLocationConvertibleLoad label)
 127     {
 128         MacroAssembler::replaceWithLoad(label);
 129     }
 130
 131     void replaceWithAddressComputation(CodeLocationConvertibleLoad label)
 132     {
 133         MacroAssembler::replaceWithAddressComputation(label);
 134     }
 135
 136     void setLoadInstructionIsActive(CodeLocationConvertibleLoad label, bool isActive)
 137     {
 138         if (isActive)
 139             replaceWithLoad(label);
 140         else
 141             replaceWithAddressComputation(label);
 142     }
 143
 144     static CodeLocationLabel startOfBranchPtrWithPatchOnRegister(CodeLocationDataLabelPtr label)
 145     {
 146         return MacroAssembler::startOfBranchPtrWithPatchOnRegister(label);
 147     }
 148
 149     static CodeLocationLabel startOfPatchableBranchPtrWithPatchOnAddress(CodeLocationDataLabelPtr label)
 150     {
 151         return MacroAssembler::startOfPatchableBranchPtrWithPatchOnAddress(label);
 152     }
 153
 154     void replaceWithJump(CodeLocationLabel instructionStart, CodeLocationLabel destination)
 155     {
 156         MacroAssembler::replaceWithJump(instructionStart, destination);
 157     }
 158
 159     // This is a *bit* of a silly API, since we currently always also repatch the
 160     // immediate after calling this. But I'm fine with that, since this just feels
 161     // less yucky.
 162     void revertJumpReplacementToBranchPtrWithPatch(CodeLocationLabel instructionStart, MacroAssembler::RegisterID reg, void* value)
 163     {
 164         MacroAssembler::revertJumpReplacementToBranchPtrWithPatch(instructionStart, reg, value);
 165     }
 166
 167     void revertJumpReplacementToPatchableBranchPtrWithPatch(CodeLocationLabel instructionStart, MacroAssembler::Address address, void* value)
 168     {
 169         MacroAssembler::revertJumpReplacementToPatchableBranchPtrWithPatch(instructionStart, address, value);
 170     }
 171
 172 private:
 173     void* m_start;
 174     size_t m_size;
 175 };
 176
 177 } // namespace JSC
 178
 179 #endif // ENABLE(ASSEMBLER)
 180
 181 #endif // RepatchBuffer_h