Re: Yet another unnecessary powerpc section

[Alan Modra <amodra@bigpond.net.au>]

On Mon, Mar 21, 2005 at 08:18:55PM -0800, H. J. Lu wrote:
> On Tue, Mar 22, 2005 at 01:46:17PM +1030, Alan Modra wrote:
> > On Tue, Mar 22, 2005 at 12:30:03AM +1030, Alan Modra wrote:
> > > 	* scripttempl/elf.sc (SBSS): Don't provide sbss start and end syms.
> > 
> > Sigh.  It appears my search through source wasn't comprehensive enough.
> > libgloss uses __sbss_start and __sbss_end.
> > 
> > 	 * elf32-ppc.c (set_linker_sym): New function, extracted from..
> > 	 (ppc_elf_set_sdata_syms): ..here.  Expand comment.  Set .sbss
> > 	 start and end syms.
> > 
> > +/* Set _SDA_BASE_, _SDA2_BASE, and sbss start and end syms.  They are
> > +   set here rather than via PROVIDE in the default linker script,
> > +   because using PROVIDE inside an output section statement results in
> > +   unnecessary output sections.  Using PROVIDE outside an output section
> > +   statement runs the risk of section alignment affecting where the
> > +   section starts.  */
> >  
> 
> We had the same problem with __XXX_array_start/__XXX_array_end. I am
> running into the same problem for a different issue. Can we can make
> this a generic ELF function:
> 
> void bfd_elf_provide_symbol (struct bfd_link_info *,
> 			     const char *sym_name,
> 			     asection *sec,
> 			     bfd_vma val);
> 
> It will define a hidden data symbol NAME defined in SEC with value VAL
> if it is undefined.

If you need it, go ahead and steal it.  :)  The function probably ought
to start with '_' to indicate that it's not part of the public bfd
interface.

-- 
Alan Modra
IBM OzLabs - Linux Technology Centre