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Unified Diff: runtime/vm/lockers.cc

Issue 1748953003: - Add assertions in MutexLocker/MonitorLocker to ensure that the code enclosed (Closed) Base URL: git@github.com:dart-lang/sdk.git@master
Patch Set: self-review-comments Created 4 years, 10 months ago
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Index: runtime/vm/lockers.cc
diff --git a/runtime/vm/lockers.cc b/runtime/vm/lockers.cc
index 839d40ccdb43d03bd1393e715dc725be89176923..ba70bca9bb2cd8738c14b59707495b3887c13ad2 100644
--- a/runtime/vm/lockers.cc
+++ b/runtime/vm/lockers.cc
@@ -59,4 +59,55 @@ SafepointMutexLocker::SafepointMutexLocker(Mutex* mutex) : mutex_(mutex) {
}
}
+
+SafepointMonitorLocker::SafepointMonitorLocker(Monitor* monitor)
+ : monitor_(monitor) {
+ ASSERT(monitor_ != NULL);
+ if (!monitor_->TryEnter()) {
+ // We did not get the lock and could potentially block, so transition
+ // accordingly.
+ Thread* thread = Thread::Current();
+ thread->set_execution_state(Thread::kThreadInBlockedState);
+ thread->EnterSafepoint();
+ monitor_->Enter();
+ // First try a fast update of the thread state to indicate it is not at a
+ // safepoint anymore.
+ uword old_state = Thread::SetAtSafepoint(true, 0);
+ uword addr =
+ reinterpret_cast<uword>(thread) + Thread::safepoint_state_offset();
+ if (AtomicOperations::CompareAndSwapWord(
+ reinterpret_cast<uword*>(addr), old_state, 0) != old_state) {
+ // Fast update failed which means we could potentially be in the middle
+ // of a safepoint operation and need to block for it.
+ SafepointHandler* handler = thread->isolate()->safepoint_handler();
Cutch 2016/03/01 15:08:07 This 'fast update of the thread state' code is the
siva 2016/03/01 18:59:53 Done.
+ handler->ExitSafepointUsingLock(thread);
+ }
+ thread->set_execution_state(Thread::kThreadInVM);
+ }
+}
+
+
+Monitor::WaitResult SafepointMonitorLocker::Wait(int64_t millis) {
+ Thread* thread = Thread::Current();
+ thread->set_execution_state(Thread::kThreadInBlockedState);
+ thread->EnterSafepoint();
+ Monitor::WaitResult result = monitor_->Wait(millis);
+ // First try a fast update of the thread state to indicate it is not at a
+ // safepoint anymore.
+ uword old_state = Thread::SetAtSafepoint(true, 0);
+ uword addr =
+ reinterpret_cast<uword>(thread) + Thread::safepoint_state_offset();
+ if (AtomicOperations::CompareAndSwapWord(
+ reinterpret_cast<uword*>(addr), old_state, 0) != old_state) {
+ // Fast update failed which means we could potentially be in the middle
+ // of a safepoint operation and need to block for it.
+ monitor_->Exit();
+ SafepointHandler* handler = thread->isolate()->safepoint_handler();
+ handler->ExitSafepointUsingLock(thread);
+ monitor_->Enter();
+ }
+ thread->set_execution_state(Thread::kThreadInVM);
+ return result;
+}
+
} // namespace dart

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