1/*
2 * Copyright (C) 2018 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 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#if ENABLE(DFG_JIT)
29
30#include "DFGEpoch.h"
31#include "DFGStructureClobberState.h"
32#include <wtf/PrintStream.h>
33
34namespace JSC { namespace DFG {
35
36class AbstractValueClobberEpoch {
37public:
38 AbstractValueClobberEpoch()
39 {
40 }
41
42 static AbstractValueClobberEpoch first(StructureClobberState clobberState)
43 {
44 AbstractValueClobberEpoch result;
45 result.m_value = Epoch::first().toUnsigned() << epochShift;
46 switch (clobberState) {
47 case StructuresAreWatched:
48 result.m_value |= watchedFlag;
49 break;
50 case StructuresAreClobbered:
51 break;
52 }
53 return result;
54 }
55
56 void clobber()
57 {
58 m_value += step;
59 m_value &= ~watchedFlag;
60 }
61
62 void observeInvalidationPoint()
63 {
64 m_value |= watchedFlag;
65 }
66
67 bool operator==(const AbstractValueClobberEpoch& other) const
68 {
69 return m_value == other.m_value;
70 }
71
72 bool operator!=(const AbstractValueClobberEpoch& other) const
73 {
74 return !(*this == other);
75 }
76
77 StructureClobberState structureClobberState() const
78 {
79 return m_value & watchedFlag ? StructuresAreWatched : StructuresAreClobbered;
80 }
81
82 Epoch clobberEpoch() const
83 {
84 return Epoch::fromUnsigned(m_value >> epochShift);
85 }
86
87 void dump(PrintStream&) const;
88
89private:
90 static constexpr unsigned step = 2;
91 static constexpr unsigned watchedFlag = 1;
92 static constexpr unsigned epochShift = 1;
93
94 unsigned m_value { 0 };
95};
96
97} } // namespace JSC::DFG
98
99#endif // ENABLE(DFG_JIT)
100