[arm] Use EABI unwind library

[Richard Henderson]

On Thu, Sep 23, 2004 at 10:22:52PM +0100, Paul Brook wrote:
> However the trickier problem is targetm.eh_fnspec_ttable_indirect. The eabi 
> can't cope with the extra level of indirection used in the function exception 
> specification lists.

Oh well.  I guess go with what you have.

> However that's totally different, and has different ideas about how exception 
> regions are arranged.

I suspect that you *cannot* make the arm exception region scheme work
without inhibiting the optimizers.  In particular, anything that 
rearranges the CFG in any way might violate region nestings.  Either
that or you generate a completely artificial region nesting that
exactly mirrors the action lists that we currently build.

Neither sounds like much fun; I agree with ignoring it for now.

Of more generality, we could probably look into splitting up and
hook-izing how we construct this eh data.  Split out sjlj from dwarf2; 
handle arm eabi separately; support windows SEH format.  But that,
of course, is a lot of work.


r~