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[rfa:ppc] Eliminate write_sp, but how?


This one liner isn't obvious.

The various ABIs have a requrement that the SP be decremented before writing anything to the stack (ignoring the red zone). This is to stop signal handlers and the like trashing the callers stack. The two PPC push_dummy_call (nee push_arguments) methods are already carefully complying to this requirement (setting SP before using the stack) and hence [deprecated] write_sp method which also sets the SP before a call is entirely redundant.

Thing is, I don't see any reason to exactly matching the ABI behavior (that thread is stopped so it won't get anything writing to its stack) and further, I think exactly matching the behavior makes the code harder to understand (I'm having trouble convincing my self that it does what I think it does :-).

So, in addition to eliminating deprecated write_sp, would it be ok to move the write SP code to the end of the push_dummy_call methods?

Andrew
2003-09-10  Andrew Cagney  <cagney@redhat.com>

	* rs6000-tdep.c (rs6000_gdbarch_init): Do not set
	"deprecated_dummy_write_sp".

Index: rs6000-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/rs6000-tdep.c,v
retrieving revision 1.155
diff -u -r1.155 rs6000-tdep.c
--- rs6000-tdep.c	9 Sep 2003 22:41:47 -0000	1.155
+++ rs6000-tdep.c	10 Sep 2003 21:03:39 -0000
@@ -2896,7 +2896,6 @@
     set_gdbarch_print_insn (gdbarch, gdb_print_insn_powerpc);
 
   set_gdbarch_write_pc (gdbarch, generic_target_write_pc);
-  set_gdbarch_deprecated_dummy_write_sp (gdbarch, deprecated_write_sp);
 
   set_gdbarch_num_regs (gdbarch, v->nregs);
   set_gdbarch_num_pseudo_regs (gdbarch, v->npregs);

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