1 | /*
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2 | * Copyright (C) 2008 Apple Inc. All rights reserved.
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3 | *
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4 | * Redistribution and use in source and binary forms, with or without
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5 | * modification, are permitted provided that the following conditions
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6 | * are met:
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7 | *
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8 | * 1. Redistributions of source code must retain the above copyright
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9 | * notice, this list of conditions and the following disclaimer.
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10 | * 2. Redistributions in binary form must reproduce the above copyright
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11 | * notice, this list of conditions and the following disclaimer in the
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12 | * documentation and/or other materials provided with the distribution.
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13 | * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
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14 | * its contributors may be used to endorse or promote products derived
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15 | * from this software without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
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18 | * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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19 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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20 | * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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21 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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22 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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23 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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24 | * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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27 | */
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28 |
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29 | #ifndef Label_h
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30 | #define Label_h
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31 |
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32 | #include "CodeBlock.h"
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33 | #include "Instruction.h"
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34 | #include <wtf/Assertions.h>
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35 | #include <wtf/Vector.h>
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36 | #include <limits.h>
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37 |
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38 | namespace JSC {
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39 |
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40 | class Label {
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41 | public:
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42 | explicit Label(CodeBlock* codeBlock)
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43 | : m_refCount(0)
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44 | , m_location(invalidLocation)
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45 | , m_codeBlock(codeBlock)
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46 | {
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47 | }
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48 |
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49 | void setLocation(unsigned location)
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50 | {
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51 | m_location = location;
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52 |
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53 | unsigned size = m_unresolvedJumps.size();
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54 | for (unsigned i = 0; i < size; ++i)
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55 | m_codeBlock->instructions()[m_unresolvedJumps[i].second].u.operand = m_location - m_unresolvedJumps[i].first;
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56 | }
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57 |
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58 | int bind(int opcode, int offset) const
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59 | {
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60 | if (m_location == invalidLocation) {
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61 | m_unresolvedJumps.append(std::make_pair(opcode, offset));
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62 | return 0;
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63 | }
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64 | return m_location - opcode;
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65 | }
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66 |
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67 | void ref() { ++m_refCount; }
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68 | void deref()
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69 | {
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70 | --m_refCount;
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71 | ASSERT(m_refCount >= 0);
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72 | }
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73 | int refCount() const { return m_refCount; }
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74 |
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75 | bool isForward() const { return m_location == invalidLocation; }
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76 |
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77 | private:
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78 | typedef Vector<std::pair<int, int>, 8> JumpVector;
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79 |
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80 | static const unsigned invalidLocation = UINT_MAX;
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81 |
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82 | int m_refCount;
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83 | unsigned m_location;
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84 | CodeBlock* m_codeBlock;
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85 | mutable JumpVector m_unresolvedJumps;
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86 | };
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87 |
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88 | } // namespace JSC
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89 |
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90 | #endif // Label_h
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