1/*
2 * Copyright (C) 2008-2018 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 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#pragma once
31
32#include "CodeLocation.h"
33#include <wtf/HashMap.h>
34#include <wtf/Vector.h>
35#include <wtf/text/StringImpl.h>
36
37namespace JSC {
38
39 struct OffsetLocation {
40 int32_t branchOffset;
41#if ENABLE(JIT)
42 CodeLocationLabel<JSSwitchPtrTag> ctiOffset;
43#endif
44 };
45
46 struct StringJumpTable {
47 typedef HashMap<RefPtr<StringImpl>, OffsetLocation> StringOffsetTable;
48 StringOffsetTable offsetTable;
49#if ENABLE(JIT)
50 CodeLocationLabel<JSSwitchPtrTag> ctiDefault; // FIXME: it should not be necessary to store this.
51#endif
52
53 inline int32_t offsetForValue(StringImpl* value, int32_t defaultOffset)
54 {
55 StringOffsetTable::const_iterator end = offsetTable.end();
56 StringOffsetTable::const_iterator loc = offsetTable.find(value);
57 if (loc == end)
58 return defaultOffset;
59 return loc->value.branchOffset;
60 }
61
62#if ENABLE(JIT)
63 inline CodeLocationLabel<JSSwitchPtrTag> ctiForValue(StringImpl* value)
64 {
65 StringOffsetTable::const_iterator end = offsetTable.end();
66 StringOffsetTable::const_iterator loc = offsetTable.find(value);
67 if (loc == end)
68 return ctiDefault;
69 return loc->value.ctiOffset;
70 }
71#endif
72
73 void clear()
74 {
75 offsetTable.clear();
76 }
77 };
78
79 struct SimpleJumpTable {
80 // FIXME: The two Vectors can be combind into one Vector<OffsetLocation>
81 Vector<int32_t> branchOffsets;
82 int32_t min;
83#if ENABLE(JIT)
84 Vector<CodeLocationLabel<JSSwitchPtrTag>> ctiOffsets;
85 CodeLocationLabel<JSSwitchPtrTag> ctiDefault;
86#endif
87
88 int32_t offsetForValue(int32_t value, int32_t defaultOffset);
89 void add(int32_t key, int32_t offset)
90 {
91 if (!branchOffsets[key])
92 branchOffsets[key] = offset;
93 }
94
95#if ENABLE(JIT)
96 void ensureCTITable()
97 {
98 ASSERT(ctiOffsets.isEmpty() || ctiOffsets.size() == branchOffsets.size());
99 ctiOffsets.grow(branchOffsets.size());
100 }
101
102 inline CodeLocationLabel<JSSwitchPtrTag> ctiForValue(int32_t value)
103 {
104 if (value >= min && static_cast<uint32_t>(value - min) < ctiOffsets.size())
105 return ctiOffsets[value - min];
106 return ctiDefault;
107 }
108#endif
109
110 void clear()
111 {
112 branchOffsets.clear();
113#if ENABLE(JIT)
114 ctiOffsets.clear();
115#endif
116 }
117 };
118
119} // namespace JSC
120