Re: [cocci] Checking SmPL test cases?

[Julia Lawall <julia.lawall@inria.fr>]

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On Sat, 8 Feb 2025, Markus Elfring wrote:

> > That seems ... simple enough?
> Can you get further development ideas from test data like the following?
>
> SmPL script example:
> @deletion@
> identifier i;
> @@
>  static inline int
>  i(...)
>  {
>  ...
> -if (rnr_elems) {...}
>  ...
>  }
>
>
> Test result:
> Markus_Elfring@Sonne:…/Projekte/Coccinelle/Probe> time spatch delete_statement3-Johannes_Berg.cocci test-beacon_len-20250206.c
> …
> diff =
> warning: deletion, node 19: statement[1,2,4,5,7,8] in my_beacon_len may be inconsistently modified
> warning: deletion, node 16: [fortrue][1,2,4,5,7] in my_beacon_len may be inconsistently modified
> warning: deletion, node 15: for[1,2,4,5,7]* in my_beacon_len may be inconsistently modified
> …
> @@ -7,12 +7,5 @@ my_beacon_len(struct cfg80211_mbssid_ele
>  {
>         int len = 0;
>
> -       if (rnr_elems) {
> -               u8 i;
> -
> -               for (i = 0; i < rnr_elems->cnt; i++)
> -                       len += rnr_elems->elem[i].len;
> -       }
> -
>         return len;
>  }
>
> real    0m0,058s
> user    0m0,041s
> sys     0m0,016s
>
>
> Another source file example:
> static inline int
> my_beacon_len(struct cfg80211_mbssid_elems *elems,
> 	      struct cfg80211_rnr_elems *rnr_elems,
> 	      u8 i)
> {
> 	int len = 0;
>
> 	if (i < elems->cnt) {
> 		len = elems->elem[i].len;
> 		if (rnr_elems) {
> 			len += rnr_elems->elem[i].len;
> 			for (i = elems->cnt; i < rnr_elems->cnt; i++)
> 				len += rnr_elems->elem[i].len;
> 		}
> 		return len;
> 	}
>
> 	return len;
> }
>
>
> Questionable test result:
> Markus_Elfring@Sonne:…/Projekte/Coccinelle/Probe> time spatch delete_statement3-Johannes_Berg.cocci test2-beacon_len-20250206.c
> …
> real    0m1,653s
> user    0m1,635s
> sys     0m0,017s
>
>
> May I expect the generation of corresponding difference output here?

No.  The matched if doesn't occur on every control-flow path.

julia