scripts/coccinelle: find constant additions that could be bit ors

Semantic patch (http://coccinelle.lip6.fr/) to check for constants that are
added but are used elsewhere as bitmasks.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/coccinelle/misc/orplus.cocci

+/// Check for constants that are added but are used elsewhere as bitmasks
+/// The results should be checked manually to ensure that the nonzero
+/// bits in the two constants are actually disjoint.
+///
+// Confidence: Moderate
+// Copyright: (C) 2013 Julia Lawall, INRIA/LIP6.  GPLv2.
+// Copyright: (C) 2013 Gilles Muller, INRIA/LIP6.  GPLv2.
+// URL: http://coccinelle.lip6.fr/
+// Comments:
+// Options: -no_includes -include_headers
+
+virtual org
+virtual report
+virtual context
+
+@r@
+constant c;
+identifier i;
+expression e;
+@@
+
+(
+e | c@i
+|
+e & c@i
+|
+e |= c@i
+|
+e &= c@i
+)
+
+@s@
+constant r.c,c1;
+identifier i1;
+position p;
+@@
+
+(
+ c1 + c - 1
+|
+*c1@i1 +@p c
+)
+
+@script:python depends on org@
+p << s.p;
+@@
+
+cocci.print_main("sum of probable bitmasks, consider |",p)
+
+@script:python depends on report@
+p << s.p;
+@@
+
+msg = "WARNING: sum of probable bitmasks, consider |"
+coccilib.report.print_report(p[0],msg)