[PATCH v2] RISC-V: Change -march parsing.

[Kito Cheng]

Hi Palmer:

Ping, do you mind accept this patch and then we'll send follow up
patch for Zifence and Zicsr?

On Mon, Dec 23, 2019 at 3:21 PM Kito Cheng <kito.cheng@gmail.com> wrote:
>
> Hi Maxim:
>
> LGTM, just need Palmer or Jim to approve :)
>
> Hi Palmer:
>
> >> +static bfd_boolean
> >> +riscv_ext_x_valid_p (const char *arg)
> >> +{
> >> +  if (!strcasecmp (arg, "x"))
> >> +    return FALSE;
> >> +
> >> +  return TRUE;
> >
> > This allows any X extension through but then goes ahead to not provide any
> > support for those extensions.  I can understand providing some scaffolding to
> > users to turn on their custom extensions, but we should fail quickly on any
> > extensions that aren't supported.
>
> We bypass any X extension now, and one concern is we can't testing any
> X parsing/combine logic if we reject that.