From: Julia Lawall <julia.lawall@lip6.fr>
To: Markus Elfring <Markus.Elfring@web.de>
Cc: Yi Wang <wang.yi59@zte.com.cn>,
Michal Marek <michal.lkml@markovi.net>,
Nicolas Palix <nicolas.palix@imag.fr>,
linux-kernel@vger.kernel.org, Wen Yang <wen.yang99@zte.com.cn>,
cocci@systeme.lip6.fr
Subject: Re: [Cocci] [v2] coccinelle: semantic code search for missing of_node_put
Date: Sat, 29 Jun 2019 09:49:04 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1906290947470.2579@hadrien> (raw)
In-Reply-To: <76641efc-2e3e-8664-03b2-4eb82f01c275@web.de>
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On Sat, 29 Jun 2019, Markus Elfring wrote:
> >> +if (x == NULL || ...) S
> >> +... when != e = (T)x
> >> + when != true x == NULL
> >
> > I wonder if this code exclusion specification is really required
> > after a null pointer was checked before.
>
> I would like to add another view for this implementation detail.
>
> The when constraint can express a software desire which can be reasonable
> to some degree. You would like to be sure that a null pointer will not occur
> after a corresponding check succeeded.
He wants to be sure that the true branch through a NULL pointer check is
not taken.
> * But I feel unsure about the circumstances under which the Coccinelle software
> can determine this aspect actually.
>
> * I find that it can eventually make sense only after the content of
> the local variable (which is identified by “x”) was modified.
> Thus I would find the exclusion of assignments more useful at this place.
I assume that it was added because it was found to be useful. Please
actually try things out before declaring them to be useless.
julia
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next prev parent reply other threads:[~2019-06-29 7:49 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-28 2:58 [Cocci] [PATCH v2] coccinelle: semantic code search for missing of_node_put Wen Yang
2019-06-28 9:38 ` Markus Elfring
2019-06-28 11:07 ` Julia Lawall
2019-06-28 14:16 ` [Cocci] [v2] " Markus Elfring
2019-06-28 14:16 ` Markus Elfring
2019-07-04 3:03 ` [Cocci] [PATCH v2] coccinelle: semantic code search for missingof_node_put wen.yang99
2019-07-04 6:28 ` [Cocci] [v2] coccinelle: semantic code search for missing of_node_put Markus Elfring
2019-07-05 5:29 ` [Cocci] [PATCH v2] coccinelle: semantic code search for missingof_node_put Julia Lawall
2019-07-05 5:57 ` [Cocci] [PATCH v2] coccinelle: semantic code search formissingof_node_put wen.yang99
2019-07-05 6:17 ` Julia Lawall
2019-07-05 6:45 ` [Cocci] [v2] coccinelle: semantic code search for missing of_node_put Markus Elfring
2019-06-29 7:40 ` Markus Elfring
2019-06-29 7:49 ` Julia Lawall [this message]
2019-06-29 8:35 ` Markus Elfring
2019-06-29 19:30 ` [Cocci] [v2] Coccinelle: Testing SmPL constraints Markus Elfring
2019-07-04 2:41 ` [Cocci] 答复: Re: [PATCH v2] coccinelle: semantic code search for missingof_node_put wen.yang99
2019-07-04 5:40 ` [Cocci] [v2] coccinelle: semantic code search for missing of_node_put Markus Elfring
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