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
| //===- llvm/Support/Mutex.h - Mutex Operating System Concept -----*- 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
//
//===----------------------------------------------------------------------===//
//
// This file declares the llvm::sys::Mutex class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_MUTEX_H
#define LLVM_SUPPORT_MUTEX_H
#include "llvm/Support/Threading.h"
#include <cassert>
#include <mutex>
namespace llvm
{
namespace sys
{
/// SmartMutex - A mutex with a compile time constant parameter that
/// indicates whether this mutex should become a no-op when we're not
/// running in multithreaded mode.
template<bool mt_only>
class SmartMutex {
std::recursive_mutex impl;
unsigned acquired = 0;
public:
bool lock() {
if (!mt_only || llvm_is_multithreaded()) {
impl.lock();
return true;
} else {
// Single-threaded debugging code. This would be racy in
// multithreaded mode, but provides not sanity checks in single
// threaded mode.
++acquired;
return true;
}
}
bool unlock() {
if (!mt_only || llvm_is_multithreaded()) {
impl.unlock();
return true;
} else {
// Single-threaded debugging code. This would be racy in
// multithreaded mode, but provides not sanity checks in single
// threaded mode.
assert(acquired && "Lock not acquired before release!");
--acquired;
return true;
}
}
bool try_lock() {
if (!mt_only || llvm_is_multithreaded())
return impl.try_lock();
else return true;
}
};
/// Mutex - A standard, always enforced mutex.
typedef SmartMutex<false> Mutex;
template <bool mt_only>
using SmartScopedLock = std::lock_guard<SmartMutex<mt_only>>;
typedef SmartScopedLock<false> ScopedLock;
}
}
#endif
|