1//===-- tsan_mutexset.h -----------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file is a part of ThreadSanitizer (TSan), a race detector.
10//
11// MutexSet holds the set of mutexes currently held by a thread.
12//===----------------------------------------------------------------------===//
13#ifndef TSAN_MUTEXSET_H
14#define TSAN_MUTEXSET_H
15
16#include "tsan_defs.h"
17
18namespace __tsan {
19
20class MutexSet {
21 public:
22  // Holds limited number of mutexes.
23  // The oldest mutexes are discarded on overflow.
24  static const uptr kMaxSize = 16;
25  struct Desc {
26    u64 id;
27    u64 epoch;
28    int count;
29    bool write;
30  };
31
32  MutexSet();
33  // The 'id' is obtained from SyncVar::GetId().
34  void Add(u64 id, bool write, u64 epoch);
35  void Del(u64 id, bool write);
36  void Remove(u64 id);  // Removes the mutex completely (if it's destroyed).
37  uptr Size() const;
38  Desc Get(uptr i) const;
39
40  void operator=(const MutexSet &other) {
41    internal_memcpy(this, &other, sizeof(*this));
42  }
43
44 private:
45#if !SANITIZER_GO
46  uptr size_;
47  Desc descs_[kMaxSize];
48#endif
49
50  void RemovePos(uptr i);
51  MutexSet(const MutexSet&);
52};
53
54// Go does not have mutexes, so do not spend memory and time.
55// (Go sync.Mutex is actually a semaphore -- can be unlocked
56// in different goroutine).
57#if SANITIZER_GO
58MutexSet::MutexSet() {}
59void MutexSet::Add(u64 id, bool write, u64 epoch) {}
60void MutexSet::Del(u64 id, bool write) {}
61void MutexSet::Remove(u64 id) {}
62void MutexSet::RemovePos(uptr i) {}
63uptr MutexSet::Size() const { return 0; }
64MutexSet::Desc MutexSet::Get(uptr i) const { return Desc(); }
65#endif
66
67}  // namespace __tsan
68
69#endif  // TSAN_MUTEXSET_H
70