Re: RFA: Add a check_pch_target_flags target hook

[Geoffrey Keating <geoffk at geoffk dot org>]

Richard Sandiford <rsandifo@redhat.com> writes:

> At the moment I'm trying to achieve the twin goals of:
> 
>   (a) getting rid of TARGET_SWITCHES and TARGET_OPTIONS; and
>   (b) applying PCH validity checks to general .opt options.
> 
> This patch is another step along that road.

This is OK.

I presume that the end-point is going to be that you can just annotate
an option with 'unsafe for PCH' and have it checked.  I like that
idea.  (I would suggest that you look at how the checking for -g
works, it's not quite as simple as '-g must match', but maybe that
kind of thing can just be a special case.)

> This loop will be able to handle all types of option, and so for most
> ports, there would be no point in handling target_flags as a special case.
> SH is (hopefully) unusual in that the architecture/ABI checks are based
> on specific masks rather than specific options.

I suspect you will find other cases in ports where only certain
combinations of options don't match.