LTO incremental linking and early debug

[Jan Hubicka]

> 
> Hmm, if that's from ltrans stage then you probably need
> 
> Index: gcc/dwarf2out.c
> ===================================================================
> --- gcc/dwarf2out.c     (revision 259764)
> +++ gcc/dwarf2out.c     (working copy)
> @@ -5835,7 +5835,7 @@ dwarf2out_die_ref_for_decl (tree decl, c
>    /* During WPA stage we currently use DIEs to store the
>       decl <-> label + offset map.  That's quite inefficient but it
>       works for now.  */
> -  if (flag_wpa)
> +  if (in_lto_p)
>      {
>        dw_die_ref ref = get_AT_ref (die, DW_AT_abstract_origin);
>        if (!ref)
> 
> we currently only ever end up here during LTRANS or compile stage.

Makes sense, for incremental link use neither of the flags. It starts
same way as -flto-partition=none compilation...
Will give it a try.

Honza