diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index 6d31c31..c47423c 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -188,6 +188,10 @@
 
     setCurrentInput(Input, AST);
 
+    // Inform the diagnostic client we are processing a source file.
+    CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(), 0);
+    HasBegunSourceFile = true;
+
     // Set the shared objects, these are reset when we finish processing the
     // file, otherwise the CompilerInstance will happily destroy them.
     CI.setFileManager(&AST->getFileManager());