[PATCH] RISC-V: Clear EF_RISCV_RVC/EF_RISCV_TSO when RVC/TSO is disabled using .attribute arch

[Nelson Chu]

Yes, "used anywhere in the object" is correct, so we should enable flags as
long as they are ever enabled.  I think the comment and code "elf_flags |=
value" in the riscv_set_rvc/tso should be clear enough to understand.

Nelson

On Mon, Nov 11, 2024 at 5:17 PM Jan Beulich <jbeulich@suse.com> wrote:

> On 11.11.2024 09:49, Yu-Cheng Liang wrote:
> > If we enable RVC/TSO using -march and disable RVC/TSO using .attribute
> > arch, EF_RISCV_RVC/EF_RISCV_TSO won't be cleared in the current
> > implementation.
>
> Right, but isn't that what is wanted? Don't the flags have the meaning
> "used anywhere in the object" rather than "used throughout the object"?
>
> Jan
>
> > --- a/gas/config/tc-riscv.c
> > +++ b/gas/config/tc-riscv.c
> > @@ -5666,7 +5666,13 @@ s_riscv_attribute (int ignored ATTRIBUTE_UNUSED)
> >        old_xlen = xlen;
> >        attr = elf_known_obj_attributes_proc (stdoutput);
> >        if (!start_assemble)
> > -       riscv_set_arch (attr[Tag_RISCV_arch].s);
> > +       {
> > +         riscv_set_arch (attr[Tag_RISCV_arch].s);
> > +         if (!riscv_opts.rvc)
> > +           elf_flags &= ~(EF_RISCV_RVC);
> > +         if (!riscv_subset_supports (&riscv_rps_as, "ztso"))
> > +           elf_flags &= ~(EF_RISCV_TSO);
> > +       }
> >        else
> >          as_fatal (_("architecture elf attributes must set before "
> >                      "any instructions"));
> > --
> > 2.45.2
>
>
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