linux-kernel - [PATCH] scripts: coccinelle: check for !(un)?likely usage

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Message-Id: <20190825130536.14683-1-efremov@linux.com>
Date:   Sun, 25 Aug 2019 16:05:36 +0300
From:   Denis Efremov <efremov@...ux.com>
To:     cocci@...teme.lip6.fr
Cc:     Denis Efremov <efremov@...ux.com>, linux-kernel@...r.kernel.org,
        Julia Lawall <Julia.Lawall@...6.fr>,
        Gilles Muller <Gilles.Muller@...6.fr>,
        Nicolas Palix <nicolas.palix@...g.fr>,
        Michal Marek <michal.lkml@...kovi.net>
Subject: [PATCH] scripts: coccinelle: check for !(un)?likely usage

This patch adds coccinelle script for detecting !likely and !unlikely
usage. It's better to use unlikely instead of !likely and vice versa.

Signed-off-by: Denis Efremov <efremov@...ux.com>
---
 scripts/coccinelle/misc/unlikely.cocci | 70 ++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 scripts/coccinelle/misc/unlikely.cocci

diff --git a/scripts/coccinelle/misc/unlikely.cocci b/scripts/coccinelle/misc/unlikely.cocci
new file mode 100644
index 000000000000..88278295d76a
--- /dev/null
+++ b/scripts/coccinelle/misc/unlikely.cocci
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/// Use unlikely instead of !likely and likely instead of !unlikely.
+///
+// Confidence: High
+// Copyright: (C) 2019 Denis Efremov, ISPRAS.
+// Options: --include-headers
+
+virtual patch
+virtual context
+virtual org
+virtual report
+
+//----------------------------------------------------------
+//  For context mode
+//----------------------------------------------------------
+
+@...ends on context disable unlikely@
+expression E;
+@@
+
+(
+* !likely(E)
+|
+* !unlikely(E)
+)
+
+//----------------------------------------------------------
+//  For patch mode
+//----------------------------------------------------------
+
+@...ends on patch disable unlikely@
+expression E;
+@@
+
+(
+-!likely(E)
++unlikely(E)
+|
+-!unlikely(E)
++likely(E)
+)
+
+//----------------------------------------------------------
+//  For org and report mode
+//----------------------------------------------------------
+
+@r depends on (org || report) disable unlikely@
+expression E;
+position p;
+@@
+
+(
+ !likely@p(E)
+|
+ !unlikely@p(E)
+)
+
+@...ipt:python depends on org@
+p << r.p;
+@@
+
+coccilib.org.print_todo(p[0], "WARNING use unlikely instead of !likely")
+
+@...ipt:python depends on report@
+p << r.p;
+@@
+
+msg="WARNING: Use unlikely instead of !likely"
+coccilib.report.print_report(p[0], msg)
+
-- 
2.21.0