[PATCH] bfd/ELF: refine PR binutils/31872 fix

[Alan Modra]

On Tue, Dec 17, 2024 at 11:59:07AM +0100, Jan Beulich wrote:
> The fix for PR binutils/31872 (commit b20ab53f81db) neglected the case
> of targets with only RELA support, where nevertheless object files using
> REL exist. In particular objcopy will create such objects for x86-64
> when converting from an i?86 ELF object (this by itself probably isn't
> quite right, but we ought to cope with what our own tools are doing).
> 
> Restore the fallback to the RELA lookup, just without re-introducing the
> blind NULL de-ref that was there before.

Fail enough.

> --- a/bfd/elfcode.h
> +++ b/bfd/elfcode.h
> @@ -1615,7 +1615,8 @@ elf_slurp_reloc_table_from_section (bfd
>        relent->addend = rela.r_addend;
>  
>        res = false;
> -      if (entsize == sizeof (Elf_External_Rela)
> +      if ((entsize == sizeof (Elf_External_Rela)
> +	   || ebd->elf_info_to_howto_rel == NULL)
>  	  && ebd->elf_info_to_howto != NULL)
>  	res = ebd->elf_info_to_howto (abfd, relent, &rela);
>        else if (ebd->elf_info_to_howto_rel != NULL)

-- 
Alan Modra