src/libcompiler_builtins/compiler-rt/lib/tsan/rtl/tsan_mutexset.cc

   1 //===-- tsan_mutexset.cc --------------------------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file is a part of ThreadSanitizer (TSan), a race detector.
  11 //
  12 //===----------------------------------------------------------------------===//
  13 #include "tsan_mutexset.h"
  14 #include "tsan_rtl.h"
  15
  16 namespace __tsan {
  17
  18 const uptr MutexSet::kMaxSize;
  19
  20 MutexSet::MutexSet() {
  21   size_ = 0;
  22   internal_memset(&descs_, 0, sizeof(descs_));
  23 }
  24
  25 void MutexSet::Add(u64 id, bool write, u64 epoch) {
  26   // Look up existing mutex with the same id.
  27   for (uptr i = 0; i < size_; i++) {
  28     if (descs_[i].id == id) {
  29       descs_[i].count++;
  30       descs_[i].epoch = epoch;
  31       return;
  32     }
  33   }
  34   // On overflow, find the oldest mutex and drop it.
  35   if (size_ == kMaxSize) {
  36     u64 minepoch = (u64)-1;
  37     u64 mini = (u64)-1;
  38     for (uptr i = 0; i < size_; i++) {
  39       if (descs_[i].epoch < minepoch) {
  40         minepoch = descs_[i].epoch;
  41         mini = i;
  42       }
  43     }
  44     RemovePos(mini);
  45     CHECK_EQ(size_, kMaxSize - 1);
  46   }
  47   // Add new mutex descriptor.
  48   descs_[size_].id = id;
  49   descs_[size_].write = write;
  50   descs_[size_].epoch = epoch;
  51   descs_[size_].count = 1;
  52   size_++;
  53 }
  54
  55 void MutexSet::Del(u64 id, bool write) {
  56   for (uptr i = 0; i < size_; i++) {
  57     if (descs_[i].id == id) {
  58       if (--descs_[i].count == 0)
  59         RemovePos(i);
  60       return;
  61     }
  62   }
  63 }
  64
  65 void MutexSet::Remove(u64 id) {
  66   for (uptr i = 0; i < size_; i++) {
  67     if (descs_[i].id == id) {
  68       RemovePos(i);
  69       return;
  70     }
  71   }
  72 }
  73
  74 void MutexSet::RemovePos(uptr i) {
  75   CHECK_LT(i, size_);
  76   descs_[i] = descs_[size_ - 1];
  77   size_--;
  78 }
  79
  80 uptr MutexSet::Size() const {
  81   return size_;
  82 }
  83
  84 MutexSet::Desc MutexSet::Get(uptr i) const {
  85   CHECK_LT(i, size_);
  86   return descs_[i];
  87 }
  88
  89 }  // namespace __tsan