Thread Safety: adding basic no thread safety analysis option

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@139310 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/AnalysisBasedWarnings.cpp b/lib/Sema/AnalysisBasedWarnings.cpp
index 41b9f3b..642638b 100644
--- a/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/lib/Sema/AnalysisBasedWarnings.cpp
@@ -1305,6 +1305,8 @@
 static void checkThreadSafety(Sema &S, AnalysisContext &AC) {
   CFG *CFGraph = AC.getCFG();
   if (!CFGraph) return;
+  const Decl *D = AC.getDecl();
+  if (D && D->getAttr<NoThreadSafetyAnalysisAttr>()) return;
 
   Lockset::Factory LocksetFactory;