add a ppcallback hook for macro definitions.

llvm-svn: 68883

clang/include/clang/Lex/PPCallbacks.h

@@ -55,10 +55,15 @@ public:
                              const std::string &Str) {
   }
   
-  /// MacroExpands - This is called Preprocessor::HandleMacroExpandedIdentifier
-  /// when a macro invocation is found.
+  /// MacroExpands - This is called by
+  /// Preprocessor::HandleMacroExpandedIdentifier when a macro invocation is
+  /// found.
   virtual void MacroExpands(const Token &Id, const MacroInfo* MI) {
   }
+  
+  /// MacroDefined - This hook is called whenever a macro definition is seen.
+  virtual void MacroDefined(const IdentifierInfo *II, const MacroInfo *MI) {
+  }
 };
 
 }  // end namespace clang

clang/lib/Lex/PPDirectives.cpp

@@ -1402,6 +1402,10 @@ void Preprocessor::HandleDefineDirective(Token &DefineTok) {
   }
   
   setMacroInfo(MacroNameTok.getIdentifierInfo(), MI);
+  
+  // If the callbacks want to know, tell them about the macro definition.
+  if (Callbacks)
+    Callbacks->MacroDefined(MacroNameTok.getIdentifierInfo(), MI);
 }
 
 /// HandleUndefDirective - Implements #undef.