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
35namespace 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//
43class RepatchBuffer {
44    typedef MacroAssemblerCodePtr CodePtr;
45
46public:
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
189private:
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
202