[PATCH] x86: Check the versioned __tls_get_addr symbol

[Alan Modra]

On Fri, Jan 19, 2018 at 10:57:37AM -0800, H.J. Lu wrote:
> --- a/bfd/elfxx-x86.c
> +++ b/bfd/elfxx-x86.c
> @@ -856,7 +856,16 @@ _bfd_x86_elf_link_check_relocs (bfd *abfd, struct bfd_link_info *info)
>  				    htab->tls_get_addr,
>  				    FALSE, FALSE, FALSE);
>  	  if (h != NULL)
> -	    elf_x86_hash_entry (h)->tls_get_addr = 1;
> +	    {
> +	      elf_x86_hash_entry (h)->tls_get_addr = 1;
> +
> +	      /* Check the versioned __tls_get_addr symbol.  */
> +	      while (h->root.type == bfd_link_hash_indirect)
> +		{
> +		  h = (struct elf_link_hash_entry *) h->root.u.i.link;
> +		  elf_x86_hash_entry (h)->tls_get_addr = 1;
> +		}
> +	    }

I think it would be a little more bomb proof to pass follow=TRUE on
the elf_link_hash_lookup call, and then always test the flag on the
real symbol (which would mean a patch to elf_i386_check_tls_transition
and elf_x86_64_check_tls_transition).  We have some really odd cases
in _bfd_elf_merge_symbol where a versioned symbol can end up pointing
at the undecorated symbol.  So it might be possible to have
  __tls_get_addr@VER -> __tls_get_addr -> __tls_get_addr@@VER
in which case you wouldn't set the flag on __tls_get_addr@VER.

-- 
Alan Modra
Australia Development Lab, IBM