tsan: add description of AcquireGlobal function
llvm-svn: 222228
diff --git a/compiler-rt/lib/tsan/rtl/tsan_rtl.h b/compiler-rt/lib/tsan/rtl/tsan_rtl.h
index 3d483bc..591d10d 100644
--- a/compiler-rt/lib/tsan/rtl/tsan_rtl.h
+++ b/compiler-rt/lib/tsan/rtl/tsan_rtl.h
@@ -666,6 +666,12 @@
void MutexRepair(ThreadState *thr, uptr pc, uptr addr); // call on EOWNERDEAD
void Acquire(ThreadState *thr, uptr pc, uptr addr);
+// AcquireGlobal synchronizes the current thread with all other threads.
+// In terms of happens-before relation, it draws a HB edge from all threads
+// (where they happen to execute right now) to the current thread. We use it to
+// handle Go finalizers. Namely, finalizer goroutine executes AcquireGlobal
+// right before executing finalizers. This provides a coarse, but simple
+// approximation of the actual required synchronization.
void AcquireGlobal(ThreadState *thr, uptr pc);
void Release(ThreadState *thr, uptr pc, uptr addr);
void ReleaseStore(ThreadState *thr, uptr pc, uptr addr);