2 files changed, 47 insertions, 1 deletions
diff --git a/include/clang/Lex/PPCallbacks.h b/include/clang/Lex/PPCallbacks.h
index ddd7415c29..ec29eec13a 100644
--- a/include/clang/Lex/PPCallbacks.h
+++ b/include/clang/Lex/PPCallbacks.h
@@ -71,6 +71,51 @@ public:
   }
 };
 
+/// PPChainedCallbacks - Simple wrapper class for chaining callbacks.
+class PPChainedCallbacks : public PPCallbacks {
+  PPCallbacks *First, *Second;
+
+public:  
+  PPChainedCallbacks(PPCallbacks *_First, PPCallbacks *_Second)
+    : First(_First), Second(_Second) {}
+  ~PPChainedCallbacks() {
+    delete Second;
+    delete First;
+  }
+
+  virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
+                           SrcMgr::CharacteristicKind FileType) {
+    First->FileChanged(Loc, Reason, FileType);
+    Second->FileChanged(Loc, Reason, FileType);
+  }
+  
+  virtual void Ident(SourceLocation Loc, const std::string &str) {
+    First->Ident(Loc, str);
+    Second->Ident(Loc, str);
+  }
+  
+  virtual void PragmaComment(SourceLocation Loc, const IdentifierInfo *Kind, 
+                             const std::string &Str) {
+    First->PragmaComment(Loc, Kind, Str);
+    Second->PragmaComment(Loc, Kind, Str);
+  }
+  
+  virtual void MacroExpands(const Token &Id, const MacroInfo* MI) {
+    First->MacroExpands(Id, MI);
+    Second->MacroExpands(Id, MI);
+  }
+  
+  virtual void MacroDefined(const IdentifierInfo *II, const MacroInfo *MI) {
+    First->MacroDefined(II, MI);
+    Second->MacroDefined(II, MI);
+  }
+
+  virtual void MacroUndefined(const IdentifierInfo *II, const MacroInfo *MI) {
+    First->MacroUndefined(II, MI);
+    Second->MacroUndefined(II, MI);
+  }
+};
+
 }  // end namespace clang
 
 #endif
diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index 2184acf0e3..5b9959c32a 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -241,7 +241,8 @@ public:
   /// it.
   PPCallbacks *getPPCallbacks() const { return Callbacks; }
   void setPPCallbacks(PPCallbacks *C) {
-    delete Callbacks;
+    if (Callbacks)
+      C = new PPChainedCallbacks(C, Callbacks);
     Callbacks = C;
   }