libsanitizer/tsan/tsan_mutexset.h

   1 //===-- tsan_mutexset.h -----------------------------------------*- C++ -*-===//
   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 // MutexSet holds the set of mutexes currently held by a thread.
  12 //===----------------------------------------------------------------------===//
  13 #ifndef TSAN_MUTEXSET_H
  14 #define TSAN_MUTEXSET_H
  15
  16 #include "tsan_defs.h"
  17
  18 namespace __tsan {
  19
  20 class MutexSet {
  21  public:
  22   // Holds limited number of mutexes.
  23   // The oldest mutexes are discarded on overflow.
  24   static const uptr kMaxSize = 16;
  25   struct Desc {
  26     u64 id;
  27     u64 epoch;
  28     int count;
  29     bool write;
  30   };
  31
  32   MutexSet();
  33   // The 'id' is obtained from SyncVar::GetId().
  34   void Add(u64 id, bool write, u64 epoch);
  35   void Del(u64 id, bool write);
  36   void Remove(u64 id);  // Removes the mutex completely (if it's destroyed).
  37   uptr Size() const;
  38   Desc Get(uptr i) const;
  39
  40   void operator=(const MutexSet &other) {
  41     internal_memcpy(this, &other, sizeof(*this));
  42   }
  43
  44  private:
  45 #if !SANITIZER_GO
  46   uptr size_;
  47   Desc descs_[kMaxSize];
  48 #endif
  49
  50   void RemovePos(uptr i);
  51   MutexSet(const MutexSet&);
  52 };
  53
  54 // Go does not have mutexes, so do not spend memory and time.
  55 // (Go sync.Mutex is actually a semaphore -- can be unlocked
  56 // in different goroutine).
  57 #if SANITIZER_GO
  58 MutexSet::MutexSet() {}
  59 void MutexSet::Add(u64 id, bool write, u64 epoch) {}
  60 void MutexSet::Del(u64 id, bool write) {}
  61 void MutexSet::Remove(u64 id) {}
  62 void MutexSet::RemovePos(uptr i) {}
  63 uptr MutexSet::Size() const { return 0; }
  64 MutexSet::Desc MutexSet::Get(uptr i) const { return Desc(); }
  65 #endif
  66
  67 }  // namespace __tsan
  68
  69 #endif  // TSAN_MUTEXSET_H