AtomicOrdering.h
5.97 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
//===-- llvm/Support/AtomicOrdering.h ---Atomic Ordering---------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// Atomic ordering constants.
///
/// These values are used by LLVM to represent atomic ordering for C++11's
/// memory model and more, as detailed in docs/Atomics.rst.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_ATOMICORDERING_H
#define LLVM_SUPPORT_ATOMICORDERING_H
#include <cstddef>
namespace llvm {
/// Atomic ordering for C11 / C++11's memody models.
///
/// These values cannot change because they are shared with standard library
/// implementations as well as with other compilers.
enum class AtomicOrderingCABI {
relaxed = 0,
consume = 1,
acquire = 2,
release = 3,
acq_rel = 4,
seq_cst = 5,
};
bool operator<(AtomicOrderingCABI, AtomicOrderingCABI) = delete;
bool operator>(AtomicOrderingCABI, AtomicOrderingCABI) = delete;
bool operator<=(AtomicOrderingCABI, AtomicOrderingCABI) = delete;
bool operator>=(AtomicOrderingCABI, AtomicOrderingCABI) = delete;
// Validate an integral value which isn't known to fit within the enum's range
// is a valid AtomicOrderingCABI.
template <typename Int> inline bool isValidAtomicOrderingCABI(Int I) {
return (Int)AtomicOrderingCABI::relaxed <= I &&
I <= (Int)AtomicOrderingCABI::seq_cst;
}
/// Atomic ordering for LLVM's memory model.
///
/// C++ defines ordering as a lattice. LLVM supplements this with NotAtomic and
/// Unordered, which are both below the C++ orders.
///
/// not_atomic-->unordered-->relaxed-->release--------------->acq_rel-->seq_cst
/// \-->consume-->acquire--/
enum class AtomicOrdering {
NotAtomic = 0,
Unordered = 1,
Monotonic = 2, // Equivalent to C++'s relaxed.
// Consume = 3, // Not specified yet.
Acquire = 4,
Release = 5,
AcquireRelease = 6,
SequentiallyConsistent = 7
};
bool operator<(AtomicOrdering, AtomicOrdering) = delete;
bool operator>(AtomicOrdering, AtomicOrdering) = delete;
bool operator<=(AtomicOrdering, AtomicOrdering) = delete;
bool operator>=(AtomicOrdering, AtomicOrdering) = delete;
// Validate an integral value which isn't known to fit within the enum's range
// is a valid AtomicOrdering.
template <typename Int> inline bool isValidAtomicOrdering(Int I) {
return static_cast<Int>(AtomicOrdering::NotAtomic) <= I &&
I <= static_cast<Int>(AtomicOrdering::SequentiallyConsistent);
}
/// String used by LLVM IR to represent atomic ordering.
inline const char *toIRString(AtomicOrdering ao) {
static const char *names[8] = {"not_atomic", "unordered", "monotonic",
"consume", "acquire", "release",
"acq_rel", "seq_cst"};
return names[static_cast<size_t>(ao)];
}
/// Returns true if ao is stronger than other as defined by the AtomicOrdering
/// lattice, which is based on C++'s definition.
inline bool isStrongerThan(AtomicOrdering ao, AtomicOrdering other) {
static const bool lookup[8][8] = {
// NA UN RX CO AC RE AR SC
/* NotAtomic */ {false, false, false, false, false, false, false, false},
/* Unordered */ { true, false, false, false, false, false, false, false},
/* relaxed */ { true, true, false, false, false, false, false, false},
/* consume */ { true, true, true, false, false, false, false, false},
/* acquire */ { true, true, true, true, false, false, false, false},
/* release */ { true, true, true, false, false, false, false, false},
/* acq_rel */ { true, true, true, true, true, true, false, false},
/* seq_cst */ { true, true, true, true, true, true, true, false},
};
return lookup[static_cast<size_t>(ao)][static_cast<size_t>(other)];
}
inline bool isAtLeastOrStrongerThan(AtomicOrdering ao, AtomicOrdering other) {
static const bool lookup[8][8] = {
// NA UN RX CO AC RE AR SC
/* NotAtomic */ { true, false, false, false, false, false, false, false},
/* Unordered */ { true, true, false, false, false, false, false, false},
/* relaxed */ { true, true, true, false, false, false, false, false},
/* consume */ { true, true, true, true, false, false, false, false},
/* acquire */ { true, true, true, true, true, false, false, false},
/* release */ { true, true, true, false, false, true, false, false},
/* acq_rel */ { true, true, true, true, true, true, true, false},
/* seq_cst */ { true, true, true, true, true, true, true, true},
};
return lookup[static_cast<size_t>(ao)][static_cast<size_t>(other)];
}
inline bool isStrongerThanUnordered(AtomicOrdering ao) {
return isStrongerThan(ao, AtomicOrdering::Unordered);
}
inline bool isStrongerThanMonotonic(AtomicOrdering ao) {
return isStrongerThan(ao, AtomicOrdering::Monotonic);
}
inline bool isAcquireOrStronger(AtomicOrdering ao) {
return isAtLeastOrStrongerThan(ao, AtomicOrdering::Acquire);
}
inline bool isReleaseOrStronger(AtomicOrdering ao) {
return isAtLeastOrStrongerThan(ao, AtomicOrdering::Release);
}
inline AtomicOrderingCABI toCABI(AtomicOrdering ao) {
static const AtomicOrderingCABI lookup[8] = {
/* NotAtomic */ AtomicOrderingCABI::relaxed,
/* Unordered */ AtomicOrderingCABI::relaxed,
/* relaxed */ AtomicOrderingCABI::relaxed,
/* consume */ AtomicOrderingCABI::consume,
/* acquire */ AtomicOrderingCABI::acquire,
/* release */ AtomicOrderingCABI::release,
/* acq_rel */ AtomicOrderingCABI::acq_rel,
/* seq_cst */ AtomicOrderingCABI::seq_cst,
};
return lookup[static_cast<size_t>(ao)];
}
} // end namespace llvm
#endif // LLVM_SUPPORT_ATOMICORDERING_H