From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,PLING_QUERY,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 251C7C43331 for ; Fri, 6 Sep 2019 20:19:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04174207FC for ; Fri, 6 Sep 2019 20:19:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394483AbfIFUTY (ORCPT ); Fri, 6 Sep 2019 16:19:24 -0400 Received: from mail2-relais-roc.national.inria.fr ([192.134.164.83]:36296 "EHLO mail2-relais-roc.national.inria.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389797AbfIFUTX (ORCPT ); Fri, 6 Sep 2019 16:19:23 -0400 X-IronPort-AV: E=Sophos;i="5.64,474,1559512800"; d="scan'208";a="400644695" Received: from abo-12-105-68.mrs.modulonet.fr (HELO hadrien) ([85.68.105.12]) by mail2-relais-roc.national.inria.fr with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Sep 2019 22:19:21 +0200 Date: Fri, 6 Sep 2019 22:19:21 +0200 (CEST) From: Julia Lawall X-X-Sender: jll@hadrien To: Denis Efremov cc: linux-kernel@vger.kernel.org, cocci@systeme.lip6.fr, Julia Lawall , Gilles Muller , Nicolas Palix , Michal Marek , Markus Elfring , Joe Perches , Rasmus Villemoes Subject: Re: [PATCH v2] scripts: coccinelle: check for !(un)?likely usage In-Reply-To: <20190829171013.22956-1-efremov@linux.com> Message-ID: References: <20190825130536.14683-1-efremov@linux.com> <20190829171013.22956-1-efremov@linux.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 29 Aug 2019, Denis Efremov wrote: > This patch adds coccinelle script for detecting !likely and > !unlikely usage. These notations are confusing. It's better > to replace !likely(x) with unlikely(!x) and !unlikely(x) with > likely(!x) for readability. > > The rule transforms !likely(x) to unlikely(!x) based on this logic: > !likely(x) iff > !__builtin_expect(!!(x), 1) iff > __builtin_expect(!!!(x), 0) iff > unlikely(!x) > > For !unlikely(x) to likely(!x): > !unlikely(x) iff > !__builtin_expect(!!(x), 0) iff > __builtin_expect(!!!(x), 1) iff > likely(!x) > > Signed-off-by: Denis Efremov > Cc: Julia Lawall > Cc: Gilles Muller > Cc: Nicolas Palix > Cc: Michal Marek > Cc: Markus Elfring > Cc: Joe Perches > Cc: Rasmus Villemoes Acked-by: Julia Lawall A small improvement though would be to improve the explicit dependency of the last four python rules on r1 and r2. Those rules won't execute unless the inherited metavariable has a value, which makes the same dependency. julia > --- > scripts/coccinelle/misc/neg_unlikely.cocci | 89 ++++++++++++++++++++++ > 1 file changed, 89 insertions(+) > create mode 100644 scripts/coccinelle/misc/neg_unlikely.cocci > > diff --git a/scripts/coccinelle/misc/neg_unlikely.cocci b/scripts/coccinelle/misc/neg_unlikely.cocci > new file mode 100644 > index 000000000000..9aac0a7ff042 > --- /dev/null > +++ b/scripts/coccinelle/misc/neg_unlikely.cocci > @@ -0,0 +1,89 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/// Use unlikely(!x) instead of !likely(x) and vice versa. > +/// Notations !unlikely(x) and !likely(x) are confusing. > +// > +// Confidence: High > +// Copyright: (C) 2019 Denis Efremov, ISPRAS. > +// Options: --no-includes --include-headers > + > +virtual patch > +virtual context > +virtual org > +virtual report > + > +//---------------------------------------------------------- > +// For context mode > +//---------------------------------------------------------- > + > +@depends on context disable unlikely@ > +expression E; > +@@ > + > +*! \( likely \| unlikely \) (E) > + > +//---------------------------------------------------------- > +// For patch mode > +//---------------------------------------------------------- > + > +@depends on patch disable unlikely@ > +expression E; > +@@ > + > +( > +-!likely(!E) > ++unlikely(E) > +| > +-!likely(E) > ++unlikely(!E) > +| > +-!unlikely(!E) > ++likely(E) > +| > +-!unlikely(E) > ++likely(!E) > +) > + > +//---------------------------------------------------------- > +// For org and report mode > +//---------------------------------------------------------- > + > +@r1 depends on (org || report) disable unlikely@ > +expression E; > +position p; > +@@ > + > +!likely@p(E) > + > +@r2 depends on (org || report) disable unlikely@ > +expression E; > +position p; > +@@ > + > +!unlikely@p(E) > + > +@script:python depends on org && r1@ > +p << r1.p; > +@@ > + > +coccilib.org.print_todo(p[0], "unlikely(!x) is more readable than !likely(x)") > + > +@script:python depends on org && r2@ > +p << r2.p; > +@@ > + > +coccilib.org.print_todo(p[0], "likely(!x) is more readable than !unlikely(x)") > + > +@script:python depends on report && r1@ > +p << r1.p; > +@@ > + > +coccilib.report.print_report(p[0], > + "unlikely(!x) is more readable than !likely(x)") > + > +@script:python depends on report && r2@ > +p << r2.p; > +@@ > + > +coccilib.report.print_report(p[0], > + "likely(!x) is more readable than !unlikely(x)") > + > -- > 2.21.0 > >