PATCH: Robustify cp_fold_obj_type_ref() for ObjC++ use - PART I

[Ziemowit Laski <zlaski at apple dot com>]

This is the ObjC part.  I'm putting the lang hook in ObjC instead of 
(only) ObjC++
just in case we may need to access it from plain C in the future.

[gcc/objc/ChangeLog]
2004-09-21  Ziemowit Laski  <zlaski@apple.com>

        * objc-act.c (objc_fold_objc_type_ref): New function.
        * objc-act.h (objc_fold_objc_type_ref): New prototype.

Index: gcc/objc/objc-act.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/objc/objc-act.c,v
retrieving revision 1.245
diff -u -3 -p -r1.245 objc-act.c
--- gcc/objc/objc-act.c 9 Sep 2004 01:19:15 -0000       1.245
+++ gcc/objc/objc-act.c 22 Sep 2004 00:25:04 -0000
@@ -7530,6 +7530,28 @@ comp_proto_with_proto (tree proto1, tree
   return (!type1 && !type2);
 }

+/* Fold an OBJ_TYPE_REF expression for ObjC method dispatches, where
+   this occurs.  ObjC method dispatches are _not_ like C++ virtual
+   member function dispatches, and we account for the difference here. 
 */
+tree
+objc_fold_obj_type_ref (tree ref, tree known_type)
+{
+#ifdef OBJCPLUS
+  tree v = BINFO_VIRTUALS (TYPE_BINFO (known_type));
+
+  /* If the receiver does not have virtual member functions, there
+     is nothing we can (or need to) do here.  */
+  if (!v)
+    return NULL_TREE;
+
+  /* Let C++ handle C++ virtual functions.  */
+  return cp_fold_obj_type_ref (ref, known_type);
+#else
+  /* For plain ObjC, we currently do not need to do anything.  */
+  return NULL_TREE;
+#endif
+}
+
 static void
 objc_start_function (tree name, tree type, tree attrs,
 #ifdef OBJCPLUS
Index: gcc/objc/objc-act.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/objc/objc-act.h,v
retrieving revision 1.30
diff -u -3 -p -r1.30 objc-act.h
--- gcc/objc/objc-act.h 8 Sep 2004 00:49:44 -0000       1.30
+++ gcc/objc/objc-act.h 22 Sep 2004 00:25:04 -0000
@@ -27,6 +27,7 @@ Boston, MA 02111-1307, USA.  */
 bool objc_init (void);
 const char *objc_printable_name (tree, int);
 void objc_finish_file (void);
+tree objc_fold_obj_type_ref (tree, tree);

 /* NB: The remaining public functions are prototyped in c-common.h, 
for the
    benefit of stub-objc.c and objc-act.c.  */

--------------------------------------------------------------
Ziemowit Laski                 1 Infinite Loop, MS 301-2K
Mac OS X Compiler Group        Cupertino, CA USA  95014-2083
Apple Computer, Inc.           +1.408.974.6229  Fax .5477