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         : m_codeBlock(codeBlock)
  49     {
  50 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
  51         RefPtr<JITCode> code = codeBlock->jitCode();
  52         m_start = code->start();
  53         m_size = code->size();
  54
  55         ExecutableAllocator::makeWritable(m_start, m_size);
  56 #endif
  57     }
  58
  59     ~RepatchBuffer()
  60     {
  61 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
  62         ExecutableAllocator::makeExecutable(m_start, m_size);
  63 #endif
  64     }
  65
  66     CodeBlock* codeBlock() const { return m_codeBlock; }
  67
  68     void relink(CodeLocationJump jump, CodeLocationLabel destination)
  69     {
  70         MacroAssembler::repatchJump(jump, destination);
  71     }
  72
  73     void relink(CodeLocationCall call, CodeLocationLabel destination)
  74     {
  75         MacroAssembler::repatchCall(call, destination);
  76     }
  77
  78     void relink(CodeLocationCall call, FunctionPtr destination)
  79     {
  80         MacroAssembler::repatchCall(call, destination);
  81     }
  82
  83     void relink(CodeLocationNearCall nearCall, CodePtr destination)
  84     {
  85         MacroAssembler::repatchNearCall(nearCall, CodeLocationLabel(destination));
  86     }
  87
  88     void relink(CodeLocationNearCall nearCall, CodeLocationLabel destination)
  89     {
  90         MacroAssembler::repatchNearCall(nearCall, destination);
  91     }
  92
  93     void repatch(CodeLocationDataLabel32 dataLabel32, int32_t value)
  94     {
  95         MacroAssembler::repatchInt32(dataLabel32, value);
  96     }
  97
  98     void repatch(CodeLocationDataLabelCompact dataLabelCompact, int32_t value)
  99     {
 100         MacroAssembler::repatchCompact(dataLabelCompact, value);
 101     }
 102
 103     void repatch(CodeLocationDataLabelPtr dataLabelPtr, void* value)
 104     {
 105         MacroAssembler::repatchPointer(dataLabelPtr, value);
 106     }
 107
 108     void relinkCallerToTrampoline(ReturnAddressPtr returnAddress, CodeLocationLabel label)
 109     {
 110         relink(CodeLocationCall(CodePtr(returnAddress)), label);
 111     }
 112
 113     void relinkCallerToTrampoline(ReturnAddressPtr returnAddress, CodePtr newCalleeFunction)
 114     {
 115         relinkCallerToTrampoline(returnAddress, CodeLocationLabel(newCalleeFunction));
 116     }
 117
 118     void relinkCallerToFunction(ReturnAddressPtr returnAddress, FunctionPtr function)
 119     {
 120         relink(CodeLocationCall(CodePtr(returnAddress)), function);
 121     }
 122
 123     void relinkNearCallerToTrampoline(ReturnAddressPtr returnAddress, CodeLocationLabel label)
 124     {
 125         relink(CodeLocationNearCall(CodePtr(returnAddress)), label);
 126     }
 127
 128     void relinkNearCallerToTrampoline(ReturnAddressPtr returnAddress, CodePtr newCalleeFunction)
 129     {
 130         relinkNearCallerToTrampoline(returnAddress, CodeLocationLabel(newCalleeFunction));
 131     }
 132
 133     void replaceWithLoad(CodeLocationConvertibleLoad label)
 134     {
 135         MacroAssembler::replaceWithLoad(label);
 136     }
 137
 138     void replaceWithAddressComputation(CodeLocationConvertibleLoad label)
 139     {
 140         MacroAssembler::replaceWithAddressComputation(label);
 141     }
 142
 143     void setLoadInstructionIsActive(CodeLocationConvertibleLoad label, bool isActive)
 144     {
 145         if (isActive)
 146             replaceWithLoad(label);
 147         else
 148             replaceWithAddressComputation(label);
 149     }
 150
 151     static CodeLocationLabel startOfBranchPtrWithPatchOnRegister(CodeLocationDataLabelPtr label)
 152     {
 153         return MacroAssembler::startOfBranchPtrWithPatchOnRegister(label);
 154     }
 155
 156     static CodeLocationLabel startOfPatchableBranchPtrWithPatchOnAddress(CodeLocationDataLabelPtr label)
 157     {
 158         return MacroAssembler::startOfPatchableBranchPtrWithPatchOnAddress(label);
 159     }
 160
 161     static CodeLocationLabel startOfPatchableBranch32WithPatchOnAddress(CodeLocationDataLabel32 label)
 162     {
 163         return MacroAssembler::startOfPatchableBranch32WithPatchOnAddress(label);
 164     }
 165
 166     void replaceWithJump(CodeLocationLabel instructionStart, CodeLocationLabel destination)
 167     {
 168         MacroAssembler::replaceWithJump(instructionStart, destination);
 169     }
 170
 171     // This is a *bit* of a silly API, since we currently always also repatch the
 172     // immediate after calling this. But I'm fine with that, since this just feels
 173     // less yucky.
 174     void revertJumpReplacementToBranchPtrWithPatch(CodeLocationLabel instructionStart, MacroAssembler::RegisterID reg, void* value)
 175     {
 176         MacroAssembler::revertJumpReplacementToBranchPtrWithPatch(instructionStart, reg, value);
 177     }
 178
 179     void revertJumpReplacementToPatchableBranchPtrWithPatch(CodeLocationLabel instructionStart, MacroAssembler::Address address, void* value)
 180     {
 181         MacroAssembler::revertJumpReplacementToPatchableBranchPtrWithPatch(instructionStart, address, value);
 182     }
 183
 184     void revertJumpReplacementToPatchableBranch32WithPatch(CodeLocationLabel instructionStart, MacroAssembler::Address address, int32_t value)
 185     {
 186         MacroAssembler::revertJumpReplacementToPatchableBranch32WithPatch(instructionStart, address, value);
 187     }
 188
 189 private:
 190     CodeBlock* m_codeBlock;
 191 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
 192     void* m_start;
 193     size_t m_size;
 194 #endif
 195 };
 196
 197 } // namespace JSC
 198
 199 #endif // ENABLE(ASSEMBLER)
 200
 201 #endif // RepatchBuffer_h