Silence tsan false-positives (tsan can't track things which are only safe due to

memory fences) in statistics registration, which works the same way that
ManagedStatic registration does.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145869 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/Statistic.h

@@ -27,6 +27,7 @@
 #define LLVM_ADT_STATISTIC_H
 
 #include "llvm/Support/Atomic.h"
+#include "llvm/Support/Valgrind.h"
 
 namespace llvm {
 class raw_ostream;
@@ -110,6 +111,7 @@ protected:
     bool tmp = Initialized;
     sys::MemoryFence();
     if (!tmp) RegisterStatistic();
+    TsanHappensAfter(this);
     return *this;
   }
   void RegisterStatistic();

lib/Support/Statistic.cpp

@@ -73,9 +73,12 @@ void Statistic::RegisterStatistic() {
     if (Enabled)
       StatInfo->addStatistic(this);
 
+    TsanHappensBefore(this);
     sys::MemoryFence();
     // Remember we have been registered.
+    TsanIgnoreWritesBegin();
     Initialized = true;
+    TsanIgnoreWritesEnd();
   }
 }