Re: [PATCH v2] MIPS: make mipsisa32 and mipsisa64 link more systematic

[YunQiang Su <syq@debian.org>]

Richard Sandiford <richard.sandiford@arm.com> 于2023年4月3日周一 22:03写道：
>
> YunQiang Su <yunqiang.su@cipunited.com> writes:
> > Introduce `static const struct mips_mach_extension mips_mach_32_64[]`
> > and `mips_mach_extends_32_64 (unsigned long base, unsigned long extension)`,
> > to make mipsisa32 and mipsisa64 interlink more systemtic.
> >
> > Normally, the ISA mipsisa64rN has two subset: mipsisa64r(N-1) and
> > mipsisa32rN. `mips_mach_extensions` can hold only mipsisa64r(N-1),
> > so we need to introduce a new instruction `mips_mach_32_64`, which holds the pair 32vs64.
> >
> > Note: R6 is not compatible with pre-R6.
> >
> > bfd/ChangeLog:
> >
> >       * elfxx-mips.c (mips_mach_extends_p): make mipsisa32 and
> >         mipsisa64 interlink more systematic.
> >         (mips_mach_32_64): new struct added.
> >         (mips_mach_extends_32_64): new function added.
>
> Sorry for the delay in pushing this.  Could you check whether it's
> the right version though?  When I build locally I get:
>
> > ---
> >  bfd/elfxx-mips.c | 40 +++++++++++++++++++++++++++++-----------
> >  1 file changed, 29 insertions(+), 11 deletions(-)
> >
> > diff --git a/bfd/elfxx-mips.c b/bfd/elfxx-mips.c
> > index 35bbd86044b..21e6396609b 100644
> > --- a/bfd/elfxx-mips.c
> > +++ b/bfd/elfxx-mips.c
> > @@ -14524,6 +14524,16 @@ struct mips_mach_extension
> >    unsigned long extension, base;
> >  };
> >
> > +/* An array that maps 64-bit architectures to the corresponding 32-bit
> > +   architectures.  */
> > +static const struct mips_mach_extension mips_mach_32_64[] =
> > +{
> > +  { bfd_mach_mipsisa64r6, bfd_mach_mipsisa32r6 },
> > +  { bfd_mach_mipsisa64r5, bfd_mach_mipsisa32r5 },
> > +  { bfd_mach_mipsisa64r3, bfd_mach_mipsisa32r3 },
> > +  { bfd_mach_mipsisa64r2, bfd_mach_mipsisa32r2 },
> > +  { bfd_mach_mipsisa64,   bfd_mach_mipsisa32 }
> > +};
> >
> >  /* An array describing how BFD machines relate to one another.  The entries
> >     are ordered topologically with MIPS I extensions listed last.  */
> > @@ -14601,29 +14611,37 @@ static const struct mips_mach_extension mips_mach_extensions[] =
> >    { bfd_mach_mips3900, bfd_mach_mips3000 }
> >  };
> >
> > -/* Return true if bfd machine EXTENSION is an extension of machine BASE.  */
> > +/* Return true if bfd machine EXTENSION is the same as BASE, or if
> > +   EXTENSION is the 64-bit equivalent of a 32-bit BASE.  */
> > +
> > +static bool
> > +mips_mach_extends_32_64 (unsigned long base, unsigned long extension)
> > +{
> > +  size_t i;
> > +
> > +  if (extension == base)
> > +    return true;
> > +
> > +  for (i = 0; i < ARRAY_SIZE (mips_mach_64_32); i++)
>
> error: ‘mips_mach_64_32’ undeclared (first use in this function); did you mean ‘mips_mach_32_64’?
>
> It looks like the previous patch had the same thing (sorry for not
> noticing).  Obviously it's a simple fix, but it would be good to have
> some reassurance that the patch has been tested beyond my crude sanity
> checks.
>
Yes, it is a typo.
Sorry for it. I won't happen anymore...

> Thanks,
> Richard
>
> > +    if (extension == mips_mach_32_64[i].extension)
> > +      return base == mips_mach_32_64[i].base;
> > +
> > +  return false;
> > +}
> >
> >  static bool
> >  mips_mach_extends_p (unsigned long base, unsigned long extension)
> >  {
> >    size_t i;
> >
> > -  if (extension == base)
> > -    return true;
> > -
> > -  if (base == bfd_mach_mipsisa32
> > -      && mips_mach_extends_p (bfd_mach_mipsisa64, extension))
> > -    return true;
> > -
> > -  if (base == bfd_mach_mipsisa32r2
> > -      && mips_mach_extends_p (bfd_mach_mipsisa64r2, extension))
> > +  if (mips_mach_extends_32_64 (base, extension))
> >      return true;
> >
> >    for (i = 0; i < ARRAY_SIZE (mips_mach_extensions); i++)
> >      if (extension == mips_mach_extensions[i].extension)
> >        {
> >       extension = mips_mach_extensions[i].base;
>
>
>
> > -     if (extension == base)
> > +     if (mips_mach_extends_32_64 (base, extension))
> >         return true;
> >        }