This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: -msep-data without -fPIC ?
- From: "Philippe De Muyter" <phdm at macqel dot be>
- To: Gunther Nikl <gni at gecko dot de>
- Cc: gcc at gcc dot gnu dot org
- Date: Tue, 17 Jan 2006 13:35:59 +0100 (CET)
- Subject: Re: -msep-data without -fPIC ?
Gunther Nikl wrote :
> On Sat, Jan 14, 2006 at 02:21:20AM +0100, Philippe De Muyter wrote:
> > For an embedded mmu-less m68k target, I would like to generate code
> > that will always run at a fixed place in memory, thus not needing to be PIC,
> > but that would access a data+bss segment that could be anywhere in memory,
> > thus needing accesses to the data segment via %a5 and an offset table.
> >
> > 1. Does that possibility already exist in gcc (I did not find it) ?
> > -msep-data currently does PI-text + PI-data.
>
> AFAICT, this doesn't exist within mainline GCC. The AmigaOS port (which
> isn't part of the official sources) implements this scheme, either with
> 16bit or 32bit displacements. The latter requires a 68020 or better.
> Note, you need binutils support as well.
Where is that AmigaOS port availaible ?
That seems to be an easier solution.
>
> > 2. If it does not exist, I plan to integrate it.
> > - From which release or branch should I start ?
> > I'd like to work on something that is stable except for my changes.
>
> You have to use current mainlines sources.
>
> > - How is it currently possible in the gcc internals to know if a
> > SYMBOL_REF points to the .text or .rodata segments ?
>
> The AmigaOS port uses SYMBOL_REF_FLAG to record this information. I believe
> SYMBOL_REF_FLAG is deprecated and there is a newer functionality to achieve
> the same.
>
> Gunther
>
Thanks for your answer
Philippe