don't diagnose empty source files, thanks Neil!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@49575 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/Lexer.cpp b/lib/Lex/Lexer.cpp
index e3daf31..0768e3b 100644
--- a/lib/Lex/Lexer.cpp
+++ b/lib/Lex/Lexer.cpp
@@ -1141,8 +1141,9 @@
     ConditionalStack.pop_back();
   }
   
-  // If the file was empty or didn't end in a newline, issue a pedwarn.
-  if (CurPtr == BufferStart || (CurPtr[-1] != '\n' && CurPtr[-1] != '\r'))
+  // C99 5.1.1.2p2: If the file is non-empty and didn't end in a newline, issue
+  // a pedwarn.
+  if (CurPtr != BufferStart && (CurPtr[-1] != '\n' && CurPtr[-1] != '\r'))
     Diag(BufferEnd, diag::ext_no_newline_eof);
   
   BufferPtr = CurPtr;