From aa21e417f24fe9be4fd8db366766fb262c96703e Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nicholas@mxc.ca>
Date: Mon, 5 Dec 2011 23:07:05 +0000
Subject: [PATCH] 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 | 2 ++
 lib/Support/Statistic.cpp    | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/include/llvm/ADT/Statistic.h b/include/llvm/ADT/Statistic.h
index b8a1a2f5c4e..b54d10b9dd3 100644
--- a/include/llvm/ADT/Statistic.h
+++ b/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();
diff --git a/lib/Support/Statistic.cpp b/lib/Support/Statistic.cpp
index 04a44a0f711..d8a6ad35ba9 100644
--- a/lib/Support/Statistic.cpp
+++ b/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();
   }
 }