Using stabs rather than dwarf2 (with Ada)

[Duncan Sands <duncan dot sands at math dot u-psud dot fr>]

I am playing with gcc from CVS, in particular the Ada frontend,
on an x86 linux box.  Question: how to have -g use stabs by default?

The default debugging format is dwarf2.  However with some
programs I get the following kind of error in gdb:

Die: DW_TAG_subrange_type (abbrev = 5, offset = 11562)
        has children: FALSE
        attributes:
                DW_AT_name (DW_FORM_string) string: "system__tasking__task_entry_index___XDLU_0__2147483647"
                DW_AT_lower_bound (DW_FORM_data1) constant: 0
                DW_AT_upper_bound (DW_FORM_data4) constant: 2147483647
                DW_AT_type (DW_FORM_ref4) constant: 1046
Dwarf Error: Cannot find type of die [in module /home/duncan/tmp/dbg2]

I thought I would try stabs instead, but this is not so easy: if I build gcc
with --with-stabs, still dwarf2 is produced when -g is used (the logic in gcc.c
is:

#  define ASM_DEBUG_SPEC                                        \
      (PREFERRED_DEBUGGING_TYPE == DBX_DEBUG                    \
       ? "%{gdwarf-2*:--gdwarf2}%{!gdwarf-2*:%{g*:--gstabs}}"   \
       : "%{gstabs*:--gstabs}%{!gstabs*:%{g*:--gdwarf2}}")

which seems to be backwards: if you prefer stabs (dbx_debug) then use
dwarf2!  But maybe I am reading it wrong).  I can compile using -gstabs
instead of -g of course, but it is a pain.  In any case, I still get dwarf2
problems because some of the Ada library seems to be compiled using -g
(I changed most of the uses of -g into -gstabs but there still seem to be
some left).  So I would like -g to mean -gstabs, so as to have no dwarf2
at all.  Does anyone know how to do this?

Thanks,

Duncan.