[Bug java/1427] gcc should allow gcj and gfortran to generate N_MAIN stab or DW_AT_entry_point dwarf2 debug info

["drow at false dot org" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #20 from drow at gcc dot gnu dot org  2006-10-17 02:40 -------
Subject: Re:  gcj should generate N_MAIN  stab or DW_AT_entry_point dwarf2
debug info

On Sat, Oct 14, 2006 at 02:17:32PM -0000, steven at gcc dot gnu dot org wrote:
> Someone should make gdb understand the DW_AT_calling_convention attribute. 
> This is the bit necessary to make it work for Fortran.  I considered stealing a
> bit on FUNCTION_DECL to mark it as the main program but it seems to me that
> this hard-coded solution should be acceptable as well (but, your thoughts?).

I don't remember the discussion entirely, and can't find it now, but I
thought that the conclusion was that DW_AT_calling_convention was not
appropriate for this purpose?  In gfortran, main-ness doesn't affect
whether the function can be called or not, or how to call it, I don't
think.

Compare to DW_CC_GNU_renesas_sh, indicating a different ABI.  A flag
for i386 regparm could also go here.

I guess the language in the standard allows this usage, but it would
make it impossible to mark a main routine as obeying a particular ABI.

Ah, here:
http://dwarf.freestandards.org/ShowIssue.php?issue=050808.2&type=closed

Maybe someone out to poke the committee again.

> -  value = targetm.dwarf_calling_convention (type);
> +  if (is_fortran ())
> +    {
> +      /* The subroutine named MAIN__ is the main program for Fortran.  */
> +      const char *subroutine_name = get_AT_string (subr_die, DW_AT_name);
> +      if (strcmp (subroutine_name, "MAIN__") == 0)
> +       value = DW_CC_program;
> +    }
> +  else
> +    value = targetm.dwarf_calling_convention (type);

Probably ought to call the target hook in the fortran case
eventually...


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=1427