Re: [PATCH] testsuite, Darwin: Add support for Mach-O function body scans.

[Andrew Pinski <pinskia@gmail.com>]

On Fri, Oct 27, 2023 at 4:00 AM Iain Sandoe <iain@sandoe.co.uk> wrote:
>
> Hi Richard,
>
> > On 26 Oct 2023, at 21:00, Iain Sandoe <iain@sandoe.co.uk> wrote:
>
> >> On 26 Oct 2023, at 20:49, Richard Sandiford <richard.sandiford@arm.com> wrote:
> >>
> >> Iain Sandoe <iains.gcc@gmail.com> writes:
> >>> This was written before Thomas' modification to the ELF-handling to allow
> >>> a config-based change for target details.  I did consider updating this
> >>> to try and use that scheme, but I think that it would sit a little
> >>> awkwardly, since there are some differences in the start-up scanning for
> >>> Mach-O.  I would say that in all probability we could improve things but
> >>> I'd like to put this forward as a well-tested initial implementation.
> >>
> >> Sorry, I would prefer to extend the existing function instead.
> >> E.g. there's already some divergence between the Mach-O version
> >> and the default version, in that the Mach-O version doesn't print
> >> verbose messages.  I also don't think that the current default code
> >> is so watertight that it'll never need to be updated in future.
> >
> > Fair enough, will explore what can be done (as I recall last I looked the
> > primary difference was in the initial start-up scan).
>
> I’ve done this as attached.
>
> For the record, when doing it, it gave rise to the same misgivings that led
> to the separate implementation before.
>
>  * as we add formats and uncover asm oddities, they all need to be handled
>    in one set of code, IMO it could be come quite convoluted.
>
>  * now making a change to the MACH-O code, means I have to check I did not
>    inadvertently break ELF (and likewise, in theory, an ELF change should check
>    MACH-O, but many folks do/can not do that).
>
> Maybe there’s some half-way-house where code can usefully be shared without
> those down-sides.

There is already gcc.test-framework which seems like a good place to
put a test for both formats so when someone changes the function, they
could run that testsuite to make sure it is still working for the
other format.
(Note I am not saying you should add it as part of this patch but it
seems like that would be the perfect place for it.)

Thanks,
Andrew

>
> Anyway, to make progress, is the revised version OK for trunk? (tested on
> aarch64-linux and aarch64-darwin).
> thanks
> Iain
>
>
>