1 //===-- tsan_mutexset.cpp -------------------------------------------------===//
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 //===----------------------------------------------------------------------===//
12 #include "tsan_mutexset.h"
13 #include "tsan_rtl.h"
14
15 namespace __tsan {
16
17 const uptr MutexSet::kMaxSize;
18
MutexSet()19 MutexSet::MutexSet() {
20 size_ = 0;
21 internal_memset(&descs_, 0, sizeof(descs_));
22 }
23
Add(u64 id,bool write,u64 epoch)24 void MutexSet::Add(u64 id, bool write, u64 epoch) {
25 // Look up existing mutex with the same id.
26 for (uptr i = 0; i < size_; i++) {
27 if (descs_[i].id == id) {
28 descs_[i].count++;
29 descs_[i].epoch = epoch;
30 return;
31 }
32 }
33 // On overflow, find the oldest mutex and drop it.
34 if (size_ == kMaxSize) {
35 u64 minepoch = (u64)-1;
36 u64 mini = (u64)-1;
37 for (uptr i = 0; i < size_; i++) {
38 if (descs_[i].epoch < minepoch) {
39 minepoch = descs_[i].epoch;
40 mini = i;
41 }
42 }
43 RemovePos(mini);
44 CHECK_EQ(size_, kMaxSize - 1);
45 }
46 // Add new mutex descriptor.
47 descs_[size_].id = id;
48 descs_[size_].write = write;
49 descs_[size_].epoch = epoch;
50 descs_[size_].count = 1;
51 size_++;
52 }
53
Del(u64 id,bool write)54 void MutexSet::Del(u64 id, bool write) {
55 for (uptr i = 0; i < size_; i++) {
56 if (descs_[i].id == id) {
57 if (--descs_[i].count == 0)
58 RemovePos(i);
59 return;
60 }
61 }
62 }
63
Remove(u64 id)64 void MutexSet::Remove(u64 id) {
65 for (uptr i = 0; i < size_; i++) {
66 if (descs_[i].id == id) {
67 RemovePos(i);
68 return;
69 }
70 }
71 }
72
RemovePos(uptr i)73 void MutexSet::RemovePos(uptr i) {
74 CHECK_LT(i, size_);
75 descs_[i] = descs_[size_ - 1];
76 size_--;
77 }
78
Size() const79 uptr MutexSet::Size() const {
80 return size_;
81 }
82
Get(uptr i) const83 MutexSet::Desc MutexSet::Get(uptr i) const {
84 CHECK_LT(i, size_);
85 return descs_[i];
86 }
87
88 } // namespace __tsan
89