void Statistic::RegisterStatistic() {
// If stats are enabled, inform StatInfo that this statistic should be
// printed.
- sys::SmartScopedLock<true> Writer(*StatLock);
+ // llvm_shutdown calls destructors while holding the ManagedStatic mutex.
+ // These destructors end up calling PrintStatistics, which takes StatLock.
+ // Since dereferencing StatInfo and StatLock can require taking the
+ // ManagedStatic mutex, doing so with StatLock held would lead to a lock
+ // order inversion. To avoid that, we dereference the ManagedStatics first,
+ // and only take StatLock afterwards.
if (!Initialized.load(std::memory_order_relaxed)) {
+ sys::SmartMutex<true> &Lock = *StatLock;
+ StatisticInfo &SI = *StatInfo;
+ sys::SmartScopedLock<true> Writer(Lock);
+ // Check Initialized again after acquiring the lock.
+ if (Initialized.load(std::memory_order_relaxed))
+ return;
if (Stats || Enabled)
- StatInfo->addStatistic(this);
+ SI.addStatistic(this);
// Remember we have been registered.
Initialized.store(true, std::memory_order_release);