[PATCH] elf: Drop GRP_COMDAT when localizing a global symbol

[Alan Modra]

On Mon, Dec 06, 2021 at 08:54:42AM -0800, H.J. Lu via Binutils wrote:
> --- a/binutils/objcopy.c
> +++ b/binutils/objcopy.c
> @@ -1696,6 +1696,21 @@ filter_symbols (bfd *abfd, bfd *obfd, asymbol **osyms,
>  		      && ! is_specified_symbol (name, keepglobal_specific_htab))
>  		  || (localize_hidden && is_hidden_symbol (sym))))
>  	    {
> +	      if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
> +		{
> +		  sec_ptr s = sym->section;
> +		  if (s != NULL
> +		      && elf_section_data (s) != NULL
> +		      && elf_group_name (s) != NULL)
> +		    {
> +		      /* When a global symbol in a COMDAT group was
> +			 changed to local, drop GRP_COMDAT on the
> +			 group.  */
> +		      s = elf_sec_group (s);
> +		      if (s != NULL && s->output_section != NULL)
> +			s->output_section->flags &= ~SEC_LINK_ONCE;
> +		    }
> +		}
>  	      sym->flags &= ~ (BSF_GLOBAL | BSF_WEAK);
>  	      sym->flags |= BSF_LOCAL;
>  	    }

I don't think this is quite correct.  Surely you only want to change
the group semantics if the group symbol changes?  This patch would
change group semantics if *any* symbol defined in the group is
localised.

-- 
Alan Modra
Australia Development Lab, IBM