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 constexpr uptr kMaxSize = 16;
25 struct Desc {
26 uptr addr;
27 StackID stack_id;
28 u32 seq;
29 u32 count;
30 bool write;
31
32 Desc() { internal_memset(this, 0, sizeof(*this)); }
33 Desc(const Desc& other) { *this = other; }
34 Desc& operator=(const MutexSet::Desc& other) {
35 internal_memcpy(this, &other, sizeof(*this));
36 return *this;
37 }
38 };
39
40 MutexSet();
41 void Reset();
42 void AddAddr(uptr addr, StackID stack_id, bool write);
43 void DelAddr(uptr addr, bool destroy = false);
44 uptr Size() const;
45 Desc Get(uptr i) const;
46
47 private:
48#if !SANITIZER_GO
49 u32 seq_ = 0;
50 uptr size_ = 0;
51 Desc descs_[kMaxSize];
52
53 void RemovePos(uptr i);
54#endif
55};
56
57// MutexSet is too large to live on stack.
58// DynamicMutexSet can be use used to create local MutexSet's.
59class DynamicMutexSet {
60 public:
61 DynamicMutexSet();
62 ~DynamicMutexSet();
63 MutexSet* operator->() { return ptr_; }
64 operator MutexSet*() { return ptr_; }
65 DynamicMutexSet(const DynamicMutexSet&) = delete;
66 DynamicMutexSet& operator=(const DynamicMutexSet&) = delete;
67
68 private:
69 MutexSet* ptr_;
70#if SANITIZER_GO
71 MutexSet set_;
72#endif
73};
74
75// Go does not have mutexes, so do not spend memory and time.
76// (Go sync.Mutex is actually a semaphore -- can be unlocked
77// in different goroutine).
78#if SANITIZER_GO
79MutexSet::MutexSet() {}
80void MutexSet::Reset() {}
81void MutexSet::AddAddr(uptr addr, StackID stack_id, bool write) {}
82void MutexSet::DelAddr(uptr addr, bool destroy) {}
83uptr MutexSet::Size() const { return 0; }
84MutexSet::Desc MutexSet::Get(uptr i) const { return Desc(); }
85DynamicMutexSet::DynamicMutexSet() : ptr_(&set_) {}
86DynamicMutexSet::~DynamicMutexSet() {}
87#endif
88
89} // namespace __tsan
90
91#endif // TSAN_MUTEXSET_H
92

source code of compiler-rt/lib/tsan/rtl/tsan_mutexset.h