1/*
2 * Copyright (C) 2008 Apple Inc. All rights reserved.
3 * Copyright (C) 2008 Cameron Zwarich <cwzwarich@uwaterloo.ca>
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1.  Redistributions of source code must retain the above copyright
10 *     notice, this list of conditions and the following disclaimer.
11 * 2.  Redistributions in binary form must reproduce the above copyright
12 *     notice, this list of conditions and the following disclaimer in the
13 *     documentation and/or other materials provided with the distribution.
14 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
15 *     its contributors may be used to endorse or promote products derived
16 *     from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
19 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
22 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
23 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
25 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#ifndef JumpTable_h
31#define JumpTable_h
32
33#include "MacroAssembler.h"
34#include <wtf/HashMap.h>
35#include <wtf/Vector.h>
36#include <wtf/text/StringImpl.h>
37
38namespace JSC {
39
40    struct OffsetLocation {
41        int32_t branchOffset;
42#if ENABLE(JIT)
43        CodeLocationLabel ctiOffset;
44#endif
45    };
46
47    struct StringJumpTable {
48        typedef HashMap<RefPtr<StringImpl>, OffsetLocation> StringOffsetTable;
49        StringOffsetTable offsetTable;
50#if ENABLE(JIT)
51        CodeLocationLabel ctiDefault; // FIXME: it should not be necessary to store this.
52#endif
53
54        inline int32_t offsetForValue(StringImpl* value, int32_t defaultOffset)
55        {
56            StringOffsetTable::const_iterator end = offsetTable.end();
57            StringOffsetTable::const_iterator loc = offsetTable.find(value);
58            if (loc == end)
59                return defaultOffset;
60            return loc->value.branchOffset;
61        }
62
63#if ENABLE(JIT)
64        inline CodeLocationLabel ctiForValue(StringImpl* value)
65        {
66            StringOffsetTable::const_iterator end = offsetTable.end();
67            StringOffsetTable::const_iterator loc = offsetTable.find(value);
68            if (loc == end)
69                return ctiDefault;
70            return loc->value.ctiOffset;
71        }
72#endif
73    };
74
75    struct SimpleJumpTable {
76        // FIXME: The two Vectors can be combind into one Vector<OffsetLocation>
77        Vector<int32_t> branchOffsets;
78        int32_t min;
79#if ENABLE(JIT)
80        Vector<CodeLocationLabel> ctiOffsets;
81        CodeLocationLabel ctiDefault;
82#endif
83
84        int32_t offsetForValue(int32_t value, int32_t defaultOffset);
85        void add(int32_t key, int32_t offset)
86        {
87            if (!branchOffsets[key])
88                branchOffsets[key] = offset;
89        }
90
91#if ENABLE(JIT)
92        inline CodeLocationLabel ctiForValue(int32_t value)
93        {
94            if (value >= min && static_cast<uint32_t>(value - min) < ctiOffsets.size())
95                return ctiOffsets[value - min];
96            return ctiDefault;
97        }
98#endif
99    };
100
101} // namespace JSC
102
103#endif // JumpTable_h
104