RFA: general prologue analysis framework

[Jim Blandy]

Ulrich Weigand <uweigand@de.ibm.com> writes:
> I've removed the pv_is_array_ref code from the s390 analyzer, because
> recent GCC (optionally) no longer uses fixed-size register save areas
> in order to reduce the amount of wasted stack space.
>
> The analyser now assumes the top-most stack slot holding an incoming
> (call-saved) register value is in fact the save area for that register.
> I don't need any 'area' functions at all any more ...

It looks like your data->gpr_slot[i] array effectively serves the same
purpose as an area.  If we had generic code to scan an area and
populate a trad_frame_cache, areas might save you code.