diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 7b87d3c..9ae38b1 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -798,6 +798,7 @@
     PreprocessorOpts.DisablePCHValidation = true;
     PreprocessorOpts.ImplicitPCHInclude = PriorImplicitPCHInclude;
     delete OverrideMainBuffer;
+    SavedMainFileBuffer = 0;
   }
   
   Clang.takeSourceManager();