Don't request a display name for an invalid location

Author: DougGregor

lib/Frontend/SerializedDiagnosticConsumer.cpp

@@ -255,16 +255,16 @@ unsigned SerializedDiagnosticConsumer::getEmitFile(
 
   // The source range that this buffer was generated from, expressed as
   // offsets into the original buffer.
-  auto originalFilename = SM.getDisplayNameForLoc(generatedInfo->originalSourceRange.Start);
   if (generatedInfo->originalSourceRange.isValid()) {
+    auto originalFilename = SM.getDisplayNameForLoc(generatedInfo->originalSourceRange.Start);
     addRangeToRecord(
         Lexer::getCharSourceRangeFromSourceRange(
             SM, generatedInfo->originalSourceRange),
         SM, originalFilename, Record
     );
   } else {
-    addLocToRecord(SourceLoc(), SM, originalFilename, Record); // Start
-    addLocToRecord(SourceLoc(), SM, originalFilename, Record); // End
+    addLocToRecord(SourceLoc(), SM, "", Record); // Start
+    addLocToRecord(SourceLoc(), SM, "", Record); // End
   }
 
   // Contents of the buffer.