[Bug bootstrap/46037] --enable-stage1-languages=c,lto --enable-languages=c,lto --with-build-config=bootstrap-lto fails on darwin

[Jan Hubicka]

> Why not retain the original code behavior unless generating lto? The patch
Because the original code bahviour is wrong.  It assumes that debug_hooks is initialized
while it is not at the point.

Honza
> below works with both a standard and lto-bootstrap on x86_64-apple-darwin10.
> 
> Index: gcc/config/darwin.c
> ===================================================================
> --- gcc/config/darwin.c    (revision 168662)
> +++ gcc/config/darwin.c    (working copy)
> @@ -2618,7 +2618,8 @@
>    if (flag_var_tracking
>        && (generating_for_darwin_version >= 9)
>        && debug_info_level >= DINFO_LEVEL_NORMAL
> -      && debug_hooks->var_location != do_nothing_debug_hooks.var_location)
> +      && (flag_generate_lto ? (write_symbols == DWARF2_DEBUG)
> +      : (debug_hooks->var_location != do_nothing_debug_hooks.var_location)))
>      flag_var_tracking_uninit = 1;
> 
>    if (MACHO_DYNAMIC_NO_PIC_P)