diff --git a/include/clang/Basic/SourceLocation.h b/include/clang/Basic/SourceLocation.h
index 4118a4c..faa5dc6 100644
--- a/include/clang/Basic/SourceLocation.h
+++ b/include/clang/Basic/SourceLocation.h
@@ -244,6 +244,8 @@
   const char* getSourceName() const;
   const FileEntry* getFileEntryForLoc() const;
   
+  bool isFileID() const { return Loc.isFileID(); }
+  
   bool operator==(const FullSourceLoc& RHS) const {
     return SrcMgr == RHS.SrcMgr && Loc == RHS.Loc;
   }