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From: Julia Lawall <julia.lawall@inria.fr>
To: David Frey <dpfrey@gmail.com>
Cc: cocci@systeme.lip6.fr
Subject: Re: [Cocci] Problem writing simple patch
Date: Wed, 27 Nov 2019 07:00:49 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.21.1911270659540.2670@hadrien> (raw)
In-Reply-To: <ce221377-e841-aef4-720d-0ea5a51102c6@gmail.com>



--- Please note the new email address ---


On Tue, 26 Nov 2019, David Frey wrote:

> On 11/25/2019 1:10 PM, Julia Lawall wrote:
> > On Mon, 25 Nov 2019, David Frey wrote:
> >
> >> Hi,
> >>
> >> I'm trying to write a .cocci file to transform all calls to a function
> >> "f(ex)" to something like this:
> >>
> >> #ifdef USE_F
> >> f(ex)
> >> #else
> >> g(ex)
> >> #endif
> >>
> >> The function has this signature:
> >> bool f(int x);
> >>
> >> This is the patch that I tried to use:
> >> @@
> >> expression ex;
> >> @@
> >> +#ifdef USE_F
> >>  f(ex)
> >> +#else
> >> +g(ex)
> >> +#endif
> >>
> >>
> >> This is the result of running it:
> >> $ spatch --show-c --sp-file test.cocci test.c
> >> init_defs_builtins: /usr/bin/../lib/coccinelle/standard.h
> >> plus: parse error:
> >>   File "test.cocci", line 7, column 1, charpos = 50
> >>   around = 'g',
> >>   whole content = +g(ex)
> >>
> >> What is wrong with the patch above?
> >
> > Coccinelle doesn't currently support adding ifdefs on expressions, only on
> > statements.
> >
> > You could try for some typical usage contexts, like
> >
> > +ifdef...
> > x = f(ex);
> > +#else
> > +x = g(ex);
> > +#endif
> >
> > julia
> >
>
>
> Hi Julia,
>
> Thanks for your explanation and your suggestion.  I ended up creating a
> new header that was like this:
>
> #ifdef SOMETHING
> #define foo_backport_x(_arg) bar_x(_arg)
> #define foo_backport_y(_arg) bar_y(_arg)
> #else
> #define foo_backport_x(_arg) foo_x(_arg)
> #define foo_backport_y(_arg) foo_y(_arg)
> #endif
>
> and then I defined coccinelle rules to change:
> foo_x -> foo_backport_x
> foo_y -> foo_backport_y
>
> It's not the most elegant solution, but it works.

Persoally, I would find lots of ifdefs around expressions in the code
rather ugly too, so I'm not sure that it is such a bad solution, although
the name is not pretty...

julia
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      reply	other threads:[~2019-11-27  6:01 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-25 19:57 [Cocci] Problem writing simple patch David Frey
2019-11-25 21:10 ` Julia Lawall
2019-11-26  7:24   ` [Cocci] Specifying conditional compilation with SmPL Markus Elfring
2019-11-26  7:47     ` Julia Lawall
2019-11-26 23:46   ` [Cocci] Problem writing simple patch David Frey
2019-11-27  6:00     ` Julia Lawall [this message]

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