[PowerPC] Tidy unwind support

[Geoffrey Keating]

Alan Modra <amodra@bigpond.net.au> writes:

> On Wed, Sep 01, 2004 at 06:19:46PM -0700, Richard Henderson wrote:
> > On Wed, Sep 01, 2004 at 11:48:53AM -0700, Geoffrey Keating wrote:
> > > Have you considered doing what ppc-darwin does, which is to move this
> > > large and complicated macro into a function in its own .c file?
> > 
> > I've considered doing that for all targets.
> 
> I'm willing to take on that task.  I'd like to implement by defining the
> function in unwind-dw2.c, which allows -funit-at-a-time to inline the
> single invocation of MD_FALLBACK_FRAME_STATE_FOR.
> 
> Perhaps
> 
> #ifdef MD_UNWIND_SUPPORT
> #include MD_UNWIND_SUPPORT
> #endif
> 
> at the start of unwind-dw2.c, and splitting out target MD_FALLBACK_*
> into a separate target header (or .c).

I don't object to this, but it's a very micro-optimisation (it may
even be a deoptimisation for the common case).  M_F_F_S_F gets called
very rarely, so it's not really worth inlining it.