Weirdness in parsing cpp macros

[Julia Lawall]

On Wed, 20 Mar 2024, Jani Nikula wrote:

> On Wed, 20 Mar 2024, Julia Lawall <julia.lawall at inria.fr> wrote:
> > On Wed, 20 Mar 2024, Jani Nikula wrote:
> >> Okay, I have another one wrt macros. :)
> >>
> >> I'm trying to add a completely new variadic macro, but it fails at
> >> "...". I've tried all sorts of things, but can't seem to be able to add
> >> a literal "...".
> >>
> >> I've tested that my cocci patch works with x's:
> >>
> >> + #define fn(p, xxx) foo(__VA_ARGS__)
> >>
> >> but when I try to make it actually variadic like:
> >>
> >> + #define fn(p, ...) foo(__VA_ARGS__)
> >>
> >> it gives me error. Is there a way to escape? Even tried to use a fresh
> >> identifier vararg = "..."; but cocci made them unique with numbering
> >> "...0" and "...1" etc.
> >
> > Put 6 dots.  It's silly, but ... is a Coccinelle thing, so we had to use
> > something else.
>
> I've tried, but it doesn't seem to work in the + side:
>
> plus: parse error:
>   File "/tmp/tmp.clvvc812Qe", line 20, column 2, charpos = 254
>   around = '#define fn(',
>   whole content = + #define fn(p, ......) __fn(__to_intel_display(p), __VA_ARGS__)

A patch is below.  I haven't tested it.  It's working its way through the
CI at the moment, but I'll be offline for the rest of the day, so I don't
think I will be able to make it public today.  But let me know if it
works.

In particular, I don't think it would work for matching or removals, but
it should work for additions.

julia

---

commit 8a637290a87ca86ca75a216ef1a7ac07c6a1fd57
Author: Julia Lawall <Julia.Lawall at inria.fr>
Date:   Thu Mar 21 09:16:07 2024 +0100

    allow ...... as a #define param in SmPL

diff --git a/parsing_cocci/parser_cocci_menhir.mly b/parsing_cocci/parser_cocci_menhir.mly
index afba9e8f..4f9be9a6 100644
--- a/parsing_cocci/parser_cocci_menhir.mly
+++ b/parsing_cocci/parser_cocci_menhir.mly
@@ -1614,6 +1614,12 @@ defineop:

 dparam: mident { Ast0_cocci.wrap(Ast0_cocci.DParam $1) }
 | TMetaDParamList { Parse_aux.meta_dparam_list $1 }
+| TVAEllipsis
+    { let id = ("...",$1) in
+      Ast0_cocci.wrap
+	(Ast0_cocci.DParam
+	   (Ast0_cocci.wrap
+	      (Ast0_cocci.Id(Parse_aux.id2mcode id)))) }

 define_param_list_option:
     empty_list_start(dparam,TEllipsis)