tsan_mutexset.cpp
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//===-- tsan_mutexset.cpp -------------------------------------------------===//
//
// 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 is a part of ThreadSanitizer (TSan), a race detector.
//
//===----------------------------------------------------------------------===//
#include "tsan_mutexset.h"
#include "tsan_rtl.h"
namespace __tsan {
const uptr MutexSet::kMaxSize;
MutexSet::MutexSet() {
size_ = 0;
internal_memset(&descs_, 0, sizeof(descs_));
}
void MutexSet::Add(u64 id, bool write, u64 epoch) {
// Look up existing mutex with the same id.
for (uptr i = 0; i < size_; i++) {
if (descs_[i].id == id) {
descs_[i].count++;
descs_[i].epoch = epoch;
return;
}
}
// On overflow, find the oldest mutex and drop it.
if (size_ == kMaxSize) {
u64 minepoch = (u64)-1;
u64 mini = (u64)-1;
for (uptr i = 0; i < size_; i++) {
if (descs_[i].epoch < minepoch) {
minepoch = descs_[i].epoch;
mini = i;
}
}
RemovePos(mini);
CHECK_EQ(size_, kMaxSize - 1);
}
// Add new mutex descriptor.
descs_[size_].id = id;
descs_[size_].write = write;
descs_[size_].epoch = epoch;
descs_[size_].count = 1;
size_++;
}
void MutexSet::Del(u64 id, bool write) {
for (uptr i = 0; i < size_; i++) {
if (descs_[i].id == id) {
if (--descs_[i].count == 0)
RemovePos(i);
return;
}
}
}
void MutexSet::Remove(u64 id) {
for (uptr i = 0; i < size_; i++) {
if (descs_[i].id == id) {
RemovePos(i);
return;
}
}
}
void MutexSet::RemovePos(uptr i) {
CHECK_LT(i, size_);
descs_[i] = descs_[size_ - 1];
size_--;
}
uptr MutexSet::Size() const {
return size_;
}
MutexSet::Desc MutexSet::Get(uptr i) const {
CHECK_LT(i, size_);
return descs_[i];
}
} // namespace __tsan