realeaseAcquire() is a new function added to TSan in support of the Go data-race detector. It's semantics is:
void ThreadClock::releaseAcquire(SyncClock *sc) const { for (int i = 0; i < kMaxThreads; i++) { tmp = clock[i]; clock[i] = max(clock[i], sc->clock[i]); sc->clock[i] = tmp; } }