Re: [PATCH v6] Introduce attribute sym_alias

[Jan Hubicka <hubicka@ucw.cz>]

> On Nov 22, 2023, Jan Hubicka <hubicka@ucw.cz> wrote:
> 
> > I wonder why you use same body aliases, which are kind of special to C++
> > frontend (and come with fixup code working around its quirks you had to
> > disable above).
> 
> TBH, I don't recall whether I had any reason to have gone down that
> path, or I just didn't realize I could have done something simpler.
> I've worked on and off on this patch for the past 3.5y, so many details
> have faded away from memory by now.  I do recall there were some
> challenges in making the sym_alias name available as an alias target
> early enough for it to be found, and this may have been related with
> these odd choices back then.  But the good news is that calling
> create_alias works just fine.  I'm suppose that creating alias
> attributes would as well, but why bother?  This looks even clearner!
> Thanks!

> diff --git a/gcc/cgraphunit.cc b/gcc/cgraphunit.cc
> index bccd2f2abb5a3..eb2d05094e989 100644
> --- a/gcc/cgraphunit.cc
> +++ b/gcc/cgraphunit.cc
> @@ -1175,7 +1175,7 @@ analyze_functions (bool first_time)
>       C++ FE is confused about the COMDAT groups being right.  */
>    if (symtab->cpp_implicit_aliases_done)
>      FOR_EACH_SYMBOL (node)
> -      if (node->cpp_implicit_alias)
> +      if (node->cpp_implicit_alias && node->analyzed)

I think you hould be able to drop this, since aliases you create now are
not same body aliases.
> +      if (VAR_P (replaced))
> +	varpool_node::create_alias (sym_node->decl, replacement);
> +      else
> +	cgraph_node::create_alias (sym_node->decl, replacement);
We probably chould have create_alias on symbol node directly, but that
is something I can clean up next stage1.

The IPA bits are fine.  I will take a look on your second patch.
Honza