1 | /* |
2 | * Copyright (C) 2008 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 | * |
8 | * 1. Redistributions of source code must retain the above copyright |
9 | * notice, this list of conditions and the following disclaimer. |
10 | * 2. Redistributions in binary form must reproduce the above copyright |
11 | * notice, this list of conditions and the following disclaimer in the |
12 | * documentation and/or other materials provided with the distribution. |
13 | * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of |
14 | * its contributors may be used to endorse or promote products derived |
15 | * from this software without specific prior written permission. |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY |
18 | * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
19 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
20 | * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY |
21 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
22 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
23 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
24 | * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
28 | |
29 | #ifndef Label_h |
30 | #define Label_h |
31 | |
32 | #include "CodeBlock.h" |
33 | #include "Instruction.h" |
34 | #include <wtf/Assertions.h> |
35 | #include <wtf/Vector.h> |
36 | #include <limits.h> |
37 | |
38 | namespace JSC { |
39 | |
40 | class Label { |
41 | public: |
42 | explicit Label(CodeBlock* codeBlock) |
43 | : m_refCount(0) |
44 | , m_location(invalidLocation) |
45 | , m_codeBlock(codeBlock) |
46 | { |
47 | } |
48 | |
49 | void setLocation(unsigned location) |
50 | { |
51 | m_location = location; |
52 | |
53 | unsigned size = m_unresolvedJumps.size(); |
54 | for (unsigned i = 0; i < size; ++i) |
55 | m_codeBlock->instructions()[m_unresolvedJumps[i].second].u.operand = m_location - m_unresolvedJumps[i].first; |
56 | } |
57 | |
58 | int bind(int opcode, int offset) const |
59 | { |
60 | if (m_location == invalidLocation) { |
61 | m_unresolvedJumps.append(val: std::make_pair(x&: opcode, y&: offset)); |
62 | return 0; |
63 | } |
64 | return m_location - opcode; |
65 | } |
66 | |
67 | void ref() { ++m_refCount; } |
68 | void deref() |
69 | { |
70 | --m_refCount; |
71 | ASSERT(m_refCount >= 0); |
72 | } |
73 | int refCount() const { return m_refCount; } |
74 | |
75 | bool isForward() const { return m_location == invalidLocation; } |
76 | |
77 | private: |
78 | typedef Vector<std::pair<int, int>, 8> JumpVector; |
79 | |
80 | static const unsigned invalidLocation = UINT_MAX; |
81 | |
82 | int m_refCount; |
83 | unsigned m_location; |
84 | CodeBlock* m_codeBlock; |
85 | mutable JumpVector m_unresolvedJumps; |
86 | }; |
87 | |
88 | } // namespace JSC |
89 | |
90 | #endif // Label_h |
91 | |