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From: Markus Elfring <Markus.Elfring@web.de>
To: Denis Efremov <efremov@linux.com>,
	cocci@systeme.lip6.fr, kernel-janitors@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
	Gilles Muller <Gilles.Muller@lip6.fr>,
	Julia Lawall <julia.lawall@lip6.fr>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	Michal Marek <michal.lkml@markovi.net>,
	Nicolas Palix <nicolas.palix@imag.fr>
Subject: Re: [RFC PATCH] coccinelle: check for integer overflow in binary search
Date: Thu, 5 Sep 2019 14:32:54 +0200	[thread overview]
Message-ID: <8f454c56-735c-0620-ead4-b59e328b0283@web.de> (raw)
In-Reply-To: <20190904221223.5281-1-efremov@linux.com>

> +identifier l, h, m;

Can expressions make sense for these metavariables?


> +@@
> +(
> + while (\(l < h\|l <= h\|(h - l) > 1\|(l + 1) < h\|l < (h - 1)\)) {
> +  ...
> +(
> +  ((l + h)@p / c)
> +|
> +  ((l + h)@p >> c)
> +)
> +  ...
> + }

* I suggest again to look at further possibilities to reduce undesirable
  code duplication also together with the usage of SmPL disjunctions.

* The condition specification might be easier to read with a few
  additional spaces (or the following variant).

* The SmPL ellipses will probably need further considerations.


+@@
+(
+ while (
+(       l \( < \| <= \) h
+|       (h - l) > 1
+|       (h - 1) > l
+|       (l + 1) < h
+)      )
+ {
+ <+...
+ ((l + h)@p \( / \| >> \) c)
+ ...+>
+ }


> +@script:python depends on report@
> +p << r.p;
> +@@
> +
> +msg="WARNING: custom implementation of bsearch is error-prone. "
> +msg+="Consider using lib/bsearch.c or fix the midpoint calculation "
> +msg+="as 'm = l + (h - l) / 2;' to prevent the arithmetic overflow."
> +coccilib.report.print_report(p[0], msg)

The Linux coding style supports to put a long string literal also into a single line.
Thus I find such a message construction nicer without the extra variable “msg”.

Regards,
Markus

  parent reply	other threads:[~2019-09-05 12:33 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-04 22:12 [RFC PATCH] coccinelle: check for integer overflow in binary search Denis Efremov
2019-09-05  6:20 ` Julia Lawall
2019-09-05  7:36   ` Denis Efremov
2019-09-05  7:51     ` Julia Lawall
2019-09-05 12:32 ` Markus Elfring [this message]
2019-09-05 14:23 ` Markus Elfring

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