diff --git a/include/llvm/Support/SourceMgr.h b/include/llvm/Support/SourceMgr.h
index a41a633ba6b..26a92bea765 100644
--- a/include/llvm/Support/SourceMgr.h
+++ b/include/llvm/Support/SourceMgr.h
@@ -171,7 +171,7 @@ public:
 
   const SourceMgr *getSourceMgr() const { return SM; }
   SMLoc getLoc() const { return Loc; }
-  const std::string &getFilename() { return Filename; }
+  const std::string &getFilename() const { return Filename; }
   int getLineNo() const { return LineNo; }
   int getColumnNo() const { return ColumnNo; }
   const std::string &getMessage() const { return Message; }