JavaScriptCore/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 #include <wtf/Platform.h>
  30
  31 #if ENABLE(ASSEMBLER)
  32
  33 #include <MacroAssembler.h>
  34 #include <wtf/Noncopyable.h>
  35
  36 namespace JSC {
  37
  38 // RepatchBuffer:
  39 //
  40 // This class is used to modify code after code generation has been completed,
  41 // and after the code has potentially already been executed.  This mechanism is
  42 // used to apply optimizations to the code.
  43 //
  44 class RepatchBuffer {
  45     typedef MacroAssemblerCodePtr CodePtr;
  46
  47 public:
  48     RepatchBuffer(CodeBlock* codeBlock)
  49     {
  50         JITCode& code = codeBlock->getJITCode();
  51         m_start = code.start();
  52         m_size = code.size();
  53
  54         ExecutableAllocator::makeWritable(m_start, m_size);
  55     }
  56
  57     ~RepatchBuffer()
  58     {
  59         ExecutableAllocator::makeExecutable(m_start, m_size);
  60     }
  61
  62     void relink(CodeLocationJump jump, CodeLocationLabel destination)
  63     {
  64         MacroAssembler::repatchJump(jump, destination);
  65     }
  66
  67     void relink(CodeLocationCall call, CodeLocationLabel destination)
  68     {
  69         MacroAssembler::repatchCall(call, destination);
  70     }
  71
  72     void relink(CodeLocationCall call, FunctionPtr destination)
  73     {
  74         MacroAssembler::repatchCall(call, destination);
  75     }
  76
  77     void relink(CodeLocationNearCall nearCall, CodePtr destination)
  78     {
  79         MacroAssembler::repatchNearCall(nearCall, CodeLocationLabel(destination));
  80     }
  81
  82     void relink(CodeLocationNearCall nearCall, CodeLocationLabel destination)
  83     {
  84         MacroAssembler::repatchNearCall(nearCall, destination);
  85     }
  86
  87     void repatch(CodeLocationDataLabel32 dataLabel32, int32_t value)
  88     {
  89         MacroAssembler::repatchInt32(dataLabel32, value);
  90     }
  91
  92     void repatch(CodeLocationDataLabelPtr dataLabelPtr, void* value)
  93     {
  94         MacroAssembler::repatchPointer(dataLabelPtr, value);
  95     }
  96
  97     void repatchLoadPtrToLEA(CodeLocationInstruction instruction)
  98     {
  99         MacroAssembler::repatchLoadPtrToLEA(instruction);
 100     }
 101
 102     void relinkCallerToTrampoline(ReturnAddressPtr returnAddress, CodeLocationLabel label)
 103     {
 104         relink(CodeLocationCall(CodePtr(returnAddress)), label);
 105     }
 106
 107     void relinkCallerToTrampoline(ReturnAddressPtr returnAddress, CodePtr newCalleeFunction)
 108     {
 109         relinkCallerToTrampoline(returnAddress, CodeLocationLabel(newCalleeFunction));
 110     }
 111
 112     void relinkCallerToFunction(ReturnAddressPtr returnAddress, FunctionPtr function)
 113     {
 114         relink(CodeLocationCall(CodePtr(returnAddress)), function);
 115     }
 116
 117     void relinkNearCallerToTrampoline(ReturnAddressPtr returnAddress, CodeLocationLabel label)
 118     {
 119         relink(CodeLocationNearCall(CodePtr(returnAddress)), label);
 120     }
 121
 122     void relinkNearCallerToTrampoline(ReturnAddressPtr returnAddress, CodePtr newCalleeFunction)
 123     {
 124         relinkNearCallerToTrampoline(returnAddress, CodeLocationLabel(newCalleeFunction));
 125     }
 126
 127 private:
 128     void* m_start;
 129     size_t m_size;
 130 };
 131
 132 } // namespace JSC
 133
 134 #endif // ENABLE(ASSEMBLER)
 135
 136 #endif // RepatchBuffer_h