Re: Weirdness in parsing cpp macros

[Jani Nikula <jani.nikula@linux.intel.com>]

On Thu, 21 Mar 2024, Julia Lawall <julia.lawall@inria.fr> wrote:
> On Wed, 20 Mar 2024, Jani Nikula wrote:
>
>> On Wed, 20 Mar 2024, Julia Lawall <julia.lawall@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.

Thanks for looking into it!

I'm afraid setting up an environment to try cocci patches is a bit too
involved for me right now.

BR,
Jani.


>
> 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@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)

-- 
Jani Nikula, Intel