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