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      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 CodeLocation_h
     27 #define CodeLocation_h
     28 
     29 #include "MacroAssemblerCodeRef.h"
     30 
     31 #if ENABLE(ASSEMBLER)
     32 
     33 namespace JSC {
     34 
     35 class CodeLocationInstruction;
     36 class CodeLocationLabel;
     37 class CodeLocationJump;
     38 class CodeLocationCall;
     39 class CodeLocationNearCall;
     40 class CodeLocationDataLabel32;
     41 class CodeLocationDataLabelPtr;
     42 
     43 // The CodeLocation* types are all pretty much do-nothing wrappers around
     44 // CodePtr (or MacroAssemblerCodePtr, to give it its full name).  These
     45 // classes only exist to provide type-safety when linking and patching code.
     46 //
     47 // The one new piece of functionallity introduced by these classes is the
     48 // ability to create (or put another way, to re-discover) another CodeLocation
     49 // at an offset from one you already know.  When patching code to optimize it
     50 // we often want to patch a number of instructions that are short, fixed
     51 // offsets apart.  To reduce memory overhead we will only retain a pointer to
     52 // one of the instructions, and we will use the *AtOffset methods provided by
     53 // CodeLocationCommon to find the other points in the code to modify.
     54 class CodeLocationCommon : public MacroAssemblerCodePtr {
     55 public:
     56     CodeLocationInstruction instructionAtOffset(int offset);
     57     CodeLocationLabel labelAtOffset(int offset);
     58     CodeLocationJump jumpAtOffset(int offset);
     59     CodeLocationCall callAtOffset(int offset);
     60     CodeLocationNearCall nearCallAtOffset(int offset);
     61     CodeLocationDataLabelPtr dataLabelPtrAtOffset(int offset);
     62     CodeLocationDataLabel32 dataLabel32AtOffset(int offset);
     63 
     64 protected:
     65     CodeLocationCommon()
     66     {
     67     }
     68 
     69     CodeLocationCommon(MacroAssemblerCodePtr location)
     70         : MacroAssemblerCodePtr(location)
     71     {
     72     }
     73 };
     74 
     75 class CodeLocationInstruction : public CodeLocationCommon {
     76 public:
     77     CodeLocationInstruction() {}
     78     explicit CodeLocationInstruction(MacroAssemblerCodePtr location)
     79         : CodeLocationCommon(location) {}
     80     explicit CodeLocationInstruction(void* location)
     81         : CodeLocationCommon(MacroAssemblerCodePtr(location)) {}
     82 };
     83 
     84 class CodeLocationLabel : public CodeLocationCommon {
     85 public:
     86     CodeLocationLabel() {}
     87     explicit CodeLocationLabel(MacroAssemblerCodePtr location)
     88         : CodeLocationCommon(location) {}
     89     explicit CodeLocationLabel(void* location)
     90         : CodeLocationCommon(MacroAssemblerCodePtr(location)) {}
     91 };
     92 
     93 class CodeLocationJump : public CodeLocationCommon {
     94 public:
     95     CodeLocationJump() {}
     96     explicit CodeLocationJump(MacroAssemblerCodePtr location)
     97         : CodeLocationCommon(location) {}
     98     explicit CodeLocationJump(void* location)
     99         : CodeLocationCommon(MacroAssemblerCodePtr(location)) {}
    100 };
    101 
    102 class CodeLocationCall : public CodeLocationCommon {
    103 public:
    104     CodeLocationCall() {}
    105     explicit CodeLocationCall(MacroAssemblerCodePtr location)
    106         : CodeLocationCommon(location) {}
    107     explicit CodeLocationCall(void* location)
    108         : CodeLocationCommon(MacroAssemblerCodePtr(location)) {}
    109 };
    110 
    111 class CodeLocationNearCall : public CodeLocationCommon {
    112 public:
    113     CodeLocationNearCall() {}
    114     explicit CodeLocationNearCall(MacroAssemblerCodePtr location)
    115         : CodeLocationCommon(location) {}
    116     explicit CodeLocationNearCall(void* location)
    117         : CodeLocationCommon(MacroAssemblerCodePtr(location)) {}
    118 };
    119 
    120 class CodeLocationDataLabel32 : public CodeLocationCommon {
    121 public:
    122     CodeLocationDataLabel32() {}
    123     explicit CodeLocationDataLabel32(MacroAssemblerCodePtr location)
    124         : CodeLocationCommon(location) {}
    125     explicit CodeLocationDataLabel32(void* location)
    126         : CodeLocationCommon(MacroAssemblerCodePtr(location)) {}
    127 };
    128 
    129 class CodeLocationDataLabelPtr : public CodeLocationCommon {
    130 public:
    131     CodeLocationDataLabelPtr() {}
    132     explicit CodeLocationDataLabelPtr(MacroAssemblerCodePtr location)
    133         : CodeLocationCommon(location) {}
    134     explicit CodeLocationDataLabelPtr(void* location)
    135         : CodeLocationCommon(MacroAssemblerCodePtr(location)) {}
    136 };
    137 
    138 inline CodeLocationInstruction CodeLocationCommon::instructionAtOffset(int offset)
    139 {
    140     ASSERT_VALID_CODE_OFFSET(offset);
    141     return CodeLocationInstruction(reinterpret_cast<char*>(dataLocation()) + offset);
    142 }
    143 
    144 inline CodeLocationLabel CodeLocationCommon::labelAtOffset(int offset)
    145 {
    146     ASSERT_VALID_CODE_OFFSET(offset);
    147     return CodeLocationLabel(reinterpret_cast<char*>(dataLocation()) + offset);
    148 }
    149 
    150 inline CodeLocationJump CodeLocationCommon::jumpAtOffset(int offset)
    151 {
    152     ASSERT_VALID_CODE_OFFSET(offset);
    153     return CodeLocationJump(reinterpret_cast<char*>(dataLocation()) + offset);
    154 }
    155 
    156 inline CodeLocationCall CodeLocationCommon::callAtOffset(int offset)
    157 {
    158     ASSERT_VALID_CODE_OFFSET(offset);
    159     return CodeLocationCall(reinterpret_cast<char*>(dataLocation()) + offset);
    160 }
    161 
    162 inline CodeLocationNearCall CodeLocationCommon::nearCallAtOffset(int offset)
    163 {
    164     ASSERT_VALID_CODE_OFFSET(offset);
    165     return CodeLocationNearCall(reinterpret_cast<char*>(dataLocation()) + offset);
    166 }
    167 
    168 inline CodeLocationDataLabelPtr CodeLocationCommon::dataLabelPtrAtOffset(int offset)
    169 {
    170     ASSERT_VALID_CODE_OFFSET(offset);
    171     return CodeLocationDataLabelPtr(reinterpret_cast<char*>(dataLocation()) + offset);
    172 }
    173 
    174 inline CodeLocationDataLabel32 CodeLocationCommon::dataLabel32AtOffset(int offset)
    175 {
    176     ASSERT_VALID_CODE_OFFSET(offset);
    177     return CodeLocationDataLabel32(reinterpret_cast<char*>(dataLocation()) + offset);
    178 }
    179 
    180 } // namespace JSC
    181 
    182 #endif // ENABLE(ASSEMBLER)
    183 
    184 #endif // CodeLocation_h
    185