libsanitizer/tsan/tsan_mutexset.cc

   1 //===-- tsan_mutexset.cc --------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of ThreadSanitizer (TSan), a race detector.
   9 //
  10 //===----------------------------------------------------------------------===//
  11 #include "tsan_mutexset.h"
  12 #include "tsan_rtl.h"
  13
  14 namespace __tsan {
  15
  16 const uptr MutexSet::kMaxSize;
  17
  18 MutexSet::MutexSet() {
  19   size_ = 0;
  20   internal_memset(&descs_, 0, sizeof(descs_));
  21 }
  22
  23 void MutexSet::Add(u64 id, bool write, u64 epoch) {
  24   // Look up existing mutex with the same id.
  25   for (uptr i = 0; i < size_; i++) {
  26     if (descs_[i].id == id) {
  27       descs_[i].count++;
  28       descs_[i].epoch = epoch;
  29       return;
  30     }
  31   }
  32   // On overflow, find the oldest mutex and drop it.
  33   if (size_ == kMaxSize) {
  34     u64 minepoch = (u64)-1;
  35     u64 mini = (u64)-1;
  36     for (uptr i = 0; i < size_; i++) {
  37       if (descs_[i].epoch < minepoch) {
  38         minepoch = descs_[i].epoch;
  39         mini = i;
  40       }
  41     }
  42     RemovePos(mini);
  43     CHECK_EQ(size_, kMaxSize - 1);
  44   }
  45   // Add new mutex descriptor.
  46   descs_[size_].id = id;
  47   descs_[size_].write = write;
  48   descs_[size_].epoch = epoch;
  49   descs_[size_].count = 1;
  50   size_++;
  51 }
  52
  53 void MutexSet::Del(u64 id, bool write) {
  54   for (uptr i = 0; i < size_; i++) {
  55     if (descs_[i].id == id) {
  56       if (--descs_[i].count == 0)
  57         RemovePos(i);
  58       return;
  59     }
  60   }
  61 }
  62
  63 void MutexSet::Remove(u64 id) {
  64   for (uptr i = 0; i < size_; i++) {
  65     if (descs_[i].id == id) {
  66       RemovePos(i);
  67       return;
  68     }
  69   }
  70 }
  71
  72 void MutexSet::RemovePos(uptr i) {
  73   CHECK_LT(i, size_);
  74   descs_[i] = descs_[size_ - 1];
  75   size_--;
  76 }
  77
  78 uptr MutexSet::Size() const {
  79   return size_;
  80 }
  81
  82 MutexSet::Desc MutexSet::Get(uptr i) const {
  83   CHECK_LT(i, size_);
  84   return descs_[i];
  85 }
  86
  87 }  // namespace __tsan