[arcmt] Don't remove retains/releases on a global variable, flag them with errors. rdar://9402555.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@135213 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ARCMigrate/TransRetainReleaseDealloc.cpp b/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
index 4eeb474..c72312b 100644
--- a/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
+++ b/lib/ARCMigrate/TransRetainReleaseDealloc.cpp
@@ -78,6 +78,15 @@
             Pass.TA.reportError(err, rec->getLocStart());
             return true;
           }
+
+          if (isGlobalVar(rec) &&
+              (E->getMethodFamily() != OMF_retain || isRemovable(E))) {
+            std::string err = "it is not safe to remove '";
+            err += E->getSelector().getAsString() + "' message on "
+                "a global variable";
+            Pass.TA.reportError(err, rec->getLocStart());
+            return true;
+          }
         }
     case OMF_dealloc:
       break;