[Cocci] Replacing one (specific!) type with another

From: Nikolaus@rath.org (Nikolaus Rath)
To: cocci@systeme.lip6.fr
Subject: [Cocci] Replacing one (specific!) type with another
Date: Sun, 09 Oct 2016 13:45:58 -0700	[thread overview]
Message-ID: <87wphhz1x5.fsf@vostro.rath.org> (raw)
In-Reply-To: <alpine.DEB.2.10.1610082317180.3373@hadrien> (Julia Lawall's message of "Sat, 8 Oct 2016 23:21:10 +0200 (CEST)")

On Oct 08 2016, Julia Lawall <julia.lawall@lip6.fr> wrote:
>> > Write separate rules for that.  You would need one case for a local
>> > variable and one case fora parameter.  You can actually probably just drop
>> > the rule you have currently.  I would imagine something like the
>> > following:
>> >
>> > @@
>> > symbol f, se; // avoid unneeded warnings from Coccinelle
>> > @@
>> >
>> > struct fuse_session *
>> > -f
>> > +se
>> >  ;
>> > <...
>> > -f
>> > +se
>> > ...>
>> > @@
>> > identifier fn;
>> > @@
>> >
>> > fn(...,struct fuse_session *f,...) { <...
>> > -f
>> > +se
>> > ...> }
>> >
>> > I think that the symbol declaration has effect in the rest of the semantic
>> > patch, and does not have to be repeated.  If you get warnings for the
>> > second rule, just copy it down.
>>
>> I don't get Coccinelle warnings, but if I just use the two rules as
>> you gave them, then it looks as if the second one isn't working:
>>
>> @@ -584,9 +584,9 @@ static struct fuse_ll_pipe *fuse_ll_get_
>>
>>  static void fuse_ll_clear_pipe(struct fuse_session *f)
>>  {
>> -	struct fuse_ll_pipe *llp = pthread_getspecific(f->pipe_key);
>> +	struct fuse_ll_pipe *llp = pthread_getspecific(se->pipe_key);
>>  	if (llp) {
>> -		pthread_setspecific(f->pipe_key, NULL);
>> +		pthread_setspecific(se->pipe_key, NULL);
>>  		fuse_ll_pipe_free(llp);
>>  	}
>>  }
>>
>>
>> Is the problem that "...," does not match nothing, i.e. *f must not be
>> the first argument of the function?
>
> It should match nothing.  What version of Coccinelle do you have?

I used 1.0.0-rc22 (from Debian stable). However, I just downloaded the
pre-compiled version from http://coccinelle.lip6.fr/download.php and it
gives the same result.

In case you want to try yourself: the sources that I'm running this on
are available at https://github.com/libfuse/libfuse.

Best,
-Nikolaus

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