libsanitizer/tsan/tsan_clock.h

   1 //===-- tsan_clock.h --------------------------------------------*- C++ -*-===//
   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 #ifndef TSAN_CLOCK_H
  12 #define TSAN_CLOCK_H
  13
  14 #include "tsan_defs.h"
  15 #include "tsan_vector.h"
  16
  17 namespace __tsan {
  18
  19 struct ClockElem {
  20   u64 epoch  : kClkBits;
  21   u64 reused : 64 - kClkBits;
  22 };
  23
  24 // The clock that lives in sync variables (mutexes, atomics, etc).
  25 class SyncClock {
  26  public:
  27   SyncClock();
  28
  29   uptr size() const {
  30     return clk_.Size();
  31   }
  32
  33   u64 get(unsigned tid) const {
  34     DCHECK_LT(tid, clk_.Size());
  35     return clk_[tid].epoch;
  36   }
  37
  38   void Reset();
  39
  40   void DebugDump(int(*printf)(const char *s, ...));
  41
  42  private:
  43   unsigned release_store_tid_;
  44   unsigned release_store_reused_;
  45   static const uptr kDirtyTids = 2;
  46   unsigned dirty_tids_[kDirtyTids];
  47   mutable Vector<ClockElem> clk_;
  48   friend struct ThreadClock;
  49 };
  50
  51 // The clock that lives in threads.
  52 struct ThreadClock {
  53  public:
  54   explicit ThreadClock(unsigned tid, unsigned reused = 0);
  55
  56   u64 get(unsigned tid) const {
  57     DCHECK_LT(tid, kMaxTidInClock);
  58     return clk_[tid].epoch;
  59   }
  60
  61   void set(unsigned tid, u64 v);
  62
  63   void set(u64 v) {
  64     DCHECK_GE(v, clk_[tid_].epoch);
  65     clk_[tid_].epoch = v;
  66   }
  67
  68   void tick() {
  69     clk_[tid_].epoch++;
  70   }
  71
  72   uptr size() const {
  73     return nclk_;
  74   }
  75
  76   void acquire(const SyncClock *src);
  77   void release(SyncClock *dst) const;
  78   void acq_rel(SyncClock *dst);
  79   void ReleaseStore(SyncClock *dst) const;
  80
  81   void DebugReset();
  82   void DebugDump(int(*printf)(const char *s, ...));
  83
  84  private:
  85   static const uptr kDirtyTids = SyncClock::kDirtyTids;
  86   const unsigned tid_;
  87   const unsigned reused_;
  88   u64 last_acquire_;
  89   uptr nclk_;
  90   ClockElem clk_[kMaxTidInClock];
  91
  92   bool IsAlreadyAcquired(const SyncClock *src) const;
  93   void UpdateCurrentThread(SyncClock *dst) const;
  94 };
  95
  96 }  // namespace __tsan
  97
  98 #endif  // TSAN_CLOCK_H