Re: [PATCH] dissect: add support for _Generic

[Luc Van Oostenryck <luc.vanoostenryck@gmail.com>]

On Fri, Jul 31, 2020 at 04:43:01PM +0200, Oleg Nesterov wrote:
> On 07/30, Luc Van Oostenryck wrote:
> >
> > On Thu, Jul 30, 2020 at 05:08:37PM +0200, Oleg Nesterov wrote:
> > > But I do not know how to improve it without serious complications, and
> >
> > Are you thinking about calling evaluate_symbol_list()
> 
> I meant, it is not simple to teach dissect() to handle this case correctly.
> It understand the types, but for example it doesn't even try to distinguish
> "int" and "float".

OK, that's fine. It's just like using a super type like 'scalar'
or 'basetype' or something.

> And I would like to avoid evaluate_expression/etc.
> 
> > or about
> > something else?
> 
> And something else. See the example above, this code is incomplete and in this
> case evaluate can't help. Ideally dissect should also report the (possible) usage
> of B.mem and C.mem.

OK, I begin to understand. You want your own type evaluation with
its own rules. evaluate_expression() and friends would indeed not help.

But I'm afraid that, once _Generic() will be used more extensively
in macros, it will create a lot of these 'possible usages' that would,
in fact, be irrelevant to the code analyzed, possibly with an explosion
of combinations.

> > > (so far) I think it doesn't worth the effort.
> >
> > Yes, _Generic() clearly makes things a bit more complicated here.
> > Same for __auto_type,
> 
> Yes, but hopefully dissect needs much more simple changes to handle __auto_type.

Yes, it should.

Thanks for the reply.

--Luc