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
14#include "sanitizer_common/sanitizer_placement_new.h"
15#include "tsan_rtl.h"
16
17namespace __tsan {
18
19MutexSet::MutexSet() {
20}
21
22void MutexSet::Reset() { internal_memset(this, 0, sizeof(*this)); }
23
24void MutexSet::AddAddr(uptr addr, StackID stack_id, bool write) {
25  // Look up existing mutex with the same id.
26  for (uptr i = 0; i < size_; i++) {
27    if (descs_[i].addr == addr) {
28      descs_[i].count++;
29      descs_[i].seq = seq_++;
30      return;
31    }
32  }
33  // On overflow, find the oldest mutex and drop it.
34  if (size_ == kMaxSize) {
35    uptr min = 0;
36    for (uptr i = 0; i < size_; i++) {
37      if (descs_[i].seq < descs_[min].seq)
38        min = i;
39    }
40    RemovePos(min);
41    CHECK_EQ(size_, kMaxSize - 1);
42  }
43  // Add new mutex descriptor.
44  descs_[size_].addr = addr;
45  descs_[size_].stack_id = stack_id;
46  descs_[size_].write = write;
47  descs_[size_].seq = seq_++;
48  descs_[size_].count = 1;
49  size_++;
50}
51
52void MutexSet::DelAddr(uptr addr, bool destroy) {
53  for (uptr i = 0; i < size_; i++) {
54    if (descs_[i].addr == addr) {
55      if (destroy || --descs_[i].count == 0)
56        RemovePos(i);
57      return;
58    }
59  }
60}
61
62void MutexSet::RemovePos(uptr i) {
63  CHECK_LT(i, size_);
64  descs_[i] = descs_[size_ - 1];
65  size_--;
66}
67
68uptr MutexSet::Size() const {
69  return size_;
70}
71
72MutexSet::Desc MutexSet::Get(uptr i) const {
73  CHECK_LT(i, size_);
74  return descs_[i];
75}
76
77DynamicMutexSet::DynamicMutexSet() : ptr_(New<MutexSet>()) {}
78DynamicMutexSet::~DynamicMutexSet() { DestroyAndFree(ptr_); }
79
80}  // namespace __tsan