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//===-- tsan_clock.h --------------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of ThreadSanitizer (TSan), a race detector.
//
//===----------------------------------------------------------------------===//
#ifndef TSAN_CLOCK_H
#define TSAN_CLOCK_H
#include "tsan_defs.h"
#include "tsan_dense_alloc.h"
namespace __tsan {
struct ClockElem {
u64 epoch : kClkBits;
u64 reused : 64 - kClkBits;
};
struct ClockBlock {
static const uptr kSize = 512;
static const uptr kTableSize = kSize / sizeof(u32);
static const uptr kClockCount = kSize / sizeof(ClockElem);
union {
u32 table[kTableSize];
ClockElem clock[kClockCount];
};
ClockBlock() {
}
};
typedef DenseSlabAlloc<ClockBlock, 1<<16, 1<<10> ClockAlloc;
typedef DenseSlabAllocCache ClockCache;
// The clock that lives in sync variables (mutexes, atomics, etc).
class SyncClock {
public:
SyncClock();
~SyncClock();
uptr size() const {
return size_;
}
u64 get(unsigned tid) const {
return elem(tid).epoch;
}
void Resize(ClockCache *c, uptr nclk);
void Reset(ClockCache *c);
void DebugDump(int(*printf)(const char *s, ...));
private:
friend struct ThreadClock;
static const uptr kDirtyTids = 2;
unsigned release_store_tid_;
unsigned release_store_reused_;
unsigned dirty_tids_[kDirtyTids];
// tab_ contains indirect pointer to a 512b block using DenseSlabAlloc.
// If size_ <= 64, then tab_ points to an array with 64 ClockElem's.
// Otherwise, tab_ points to an array with 128 u32 elements,
// each pointing to the second-level 512b block with 64 ClockElem's.
ClockBlock *tab_;
u32 tab_idx_;
u32 size_;
ClockElem &elem(unsigned tid) const;
};
// The clock that lives in threads.
struct ThreadClock {
public:
typedef DenseSlabAllocCache Cache;
explicit ThreadClock(unsigned tid, unsigned reused = 0);
u64 get(unsigned tid) const {
DCHECK_LT(tid, kMaxTidInClock);
return clk_[tid].epoch;
}
void set(ClockCache *c, unsigned tid, u64 v);
void set(u64 v) {
DCHECK_GE(v, clk_[tid_].epoch);
clk_[tid_].epoch = v;
}
void tick() {
clk_[tid_].epoch++;
}
uptr size() const {
return nclk_;
}
void acquire(ClockCache *c, const SyncClock *src);
void release(ClockCache *c, SyncClock *dst) const;
void acq_rel(ClockCache *c, SyncClock *dst);
void ReleaseStore(ClockCache *c, SyncClock *dst) const;
void ResetCached(ClockCache *c);
void DebugReset();
void DebugDump(int(*printf)(const char *s, ...));
private:
static const uptr kDirtyTids = SyncClock::kDirtyTids;
const unsigned tid_;
const unsigned reused_;
u64 last_acquire_;
uptr nclk_;
ClockElem clk_[kMaxTidInClock];
bool IsAlreadyAcquired(const SyncClock *src) const;
void UpdateCurrentThread(SyncClock *dst) const;
};
} // namespace __tsan
#endif // TSAN_CLOCK_H
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