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
38namespace 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

source code of qtscript/src/3rdparty/javascriptcore/JavaScriptCore/bytecompiler/Label.h