add a callback for macro expansion, based on a patch by Paolo Bolzoni!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@66799 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp
index 84056c3..712918b 100644
--- a/lib/Lex/PPMacroExpansion.cpp
+++ b/lib/Lex/PPMacroExpansion.cpp
@@ -150,6 +150,8 @@
 /// expanded as a macro, handle it and return the next token as 'Identifier'.
 bool Preprocessor::HandleMacroExpandedIdentifier(Token &Identifier, 
                                                  MacroInfo *MI) {
+  if (Callbacks) Callbacks->MacroExpands(Identifier, MI);
+  
   // If this is a macro exapnsion in the "#if !defined(x)" line for the file,
   // then the macro could expand to different things in other contexts, we need
   // to disable the optimization in this case.