[Bug target/65780] [5/6 Regression] Uninitialized common handling in executables

["law at redhat dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65780

--- Comment #29 from Jeffrey A. Law <law at redhat dot com> ---
Oh how I wish all this stuff was better documented, both in the GCC sources and
at a higher level in some linkers/loaders documentation.

ix86_binds_local_p needs a function comment.  I think with a function comment,
no comments would be needed in the function body.

I think it's also advisable to get a function comment for the
default_binds_local* that don't currently have one. 

What I'm trying to wrap my head around is what "defined_locally" really means. 
Is it a "must" or "maybe" property when it gets set in default_binds_local_p_3?

If it's a must property, then "common_maybe_local" seems mis-named and/or
mis-used (the former seems most likely to me).

If it's a maybe property, then why is a common uninit local filtered out?  At
this point we don't know if a common uninit local will be defined locally or
not, so it's a maybe.

I can probably go forward with an approval or specific change recommendations
that would lead to approval once someone can tell me if defined_locally is a
maybe or must property.