diff --git a/include/clang/Analysis/PathSensitive/Checkers/UndefinedArgChecker.h b/include/clang/Analysis/PathSensitive/Checkers/UndefinedArgChecker.h
index ebb7f37f55..7f4e7d524f 100644
--- a/include/clang/Analysis/PathSensitive/Checkers/UndefinedArgChecker.h
+++ b/include/clang/Analysis/PathSensitive/Checkers/UndefinedArgChecker.h
@@ -12,6 +12,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+#ifndef LLVM_CLANG_UNDEFARGCHECKER
+#define LLVM_CLANG_UNDEFARGCHECKER
+
 #include "clang/Analysis/PathSensitive/CheckerVisitor.h"
 
 namespace clang {
@@ -28,3 +31,4 @@ public:
 };
 
 }
+#endif