libsanitizer/tsan/tsan_mutexset.cpp

   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
  17 namespace __tsan {
  18
  19 MutexSet::MutexSet() {
  20 }
  21
  22 void MutexSet::Reset() { internal_memset(this, 0, sizeof(*this)); }
  23
  24 void 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
  52 void 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
  62 void MutexSet::RemovePos(uptr i) {
  63   CHECK_LT(i, size_);
  64   descs_[i] = descs_[size_ - 1];
  65   size_--;
  66 }
  67
  68 uptr MutexSet::Size() const {
  69   return size_;
  70 }
  71
  72 MutexSet::Desc MutexSet::Get(uptr i) const {
  73   CHECK_LT(i, size_);
  74   return descs_[i];
  75 }
  76
  77 DynamicMutexSet::DynamicMutexSet() : ptr_(New<MutexSet>()) {}
  78 DynamicMutexSet::~DynamicMutexSet() { DestroyAndFree(ptr_); }
  79
  80 }  // namespace __tsan