[RFA] rs6000-tdep.c: Fix `return' from stop in call dummy

["Peter.Schauer" <Peter dot Schauer at regent dot e-technik dot tu-muenchen dot de>]

[RFA] rs6000-tdep.c:  Fix `return' from stop in call dummy

If a `return' is issued after a stop in a call dummy, rs6000_pop_frame
currently does not recognize the dummy frame, as it is testing for
stop_stack_dummy (which is a hack anyway), instead of using PC_IN_CALL_DUMMY.

Here is a fix, it will be needed for the upcoming additional callfuncs
testcases:

	* rs6000-tdep.c (rs6000_pop_frame):  Use PC_IN_CALL_DUMMY to test
	for call dummy instead of accessing stop_stack_dummy, which does
	not work if we `return' from a stop in a call dummy.
	(rs6000_gdbarch_init):  Use generic_save_dummy_frame_tos for
	dummy_frame_tos function to make PC_IN_CALL_DUMMY work.

*** ./rs6000-tdep.c.orig	Sat Aug  5 11:37:42 2000
--- ./rs6000-tdep.c	Fri Sep 15 21:36:51 2000
***************
*** 671,679 ****
    frames, etc. 
  *************************************************************************/
  
- extern int stop_stack_dummy;
  
- 
  /* Pop the innermost frame, go back to the caller. */
  
  static void
--- 671,677 ----
***************
*** 687,693 ****
    pc = read_pc ();
    sp = FRAME_FP (frame);
  
!   if (stop_stack_dummy)
      {
        generic_pop_dummy_frame ();
        flush_cached_frames ();
--- 685,691 ----
    pc = read_pc ();
    sp = FRAME_FP (frame);
  
!   if (PC_IN_CALL_DUMMY (frame->pc, frame->frame, frame->frame))
      {
        generic_pop_dummy_frame ();
        flush_cached_frames ();
***************
*** 2140,2145 ****
--- 2138,2144 ----
    set_gdbarch_get_saved_register (gdbarch, generic_get_saved_register);
    set_gdbarch_fix_call_dummy (gdbarch, rs6000_fix_call_dummy);
    set_gdbarch_push_dummy_frame (gdbarch, generic_push_dummy_frame);
+   set_gdbarch_save_dummy_frame_tos (gdbarch, generic_save_dummy_frame_tos);
    set_gdbarch_push_return_address (gdbarch, ppc_push_return_address);
    set_gdbarch_believe_pcc_promotion (gdbarch, 1);
    set_gdbarch_coerce_float_to_double (gdbarch, rs6000_coerce_float_to_double);

-- 
Peter Schauer			pes@regent.e-technik.tu-muenchen.de