![Julia Lawall](/assets/img/avatar_default.png)
Adding two #define constants is less common than performing & and | operations on them, so put the addition first to reduce the set of cases that have to be considered in detail. At the same time, add & and | patterns for both arguments of +, to account for commutativity and obtain more results. Running time is divided by 3 when applying this to the whole kernel on my laptop with an Intel i5-6200U CPU. Signed-off-by: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
71 lines
1 KiB
Plaintext
71 lines
1 KiB
Plaintext
/// Check for constants that are added but are used elsewhere as bitmasks
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/// The results should be checked manually to ensure that the nonzero
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/// bits in the two constants are actually disjoint.
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///
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// Confidence: Moderate
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// Copyright: (C) 2013 Julia Lawall, INRIA/LIP6. GPLv2.
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// Copyright: (C) 2013 Gilles Muller, INRIA/LIP6. GPLv2.
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// URL: http://coccinelle.lip6.fr/
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// Comments:
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// Options: --no-includes --include-headers
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virtual org
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virtual report
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virtual context
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@r@
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constant c,c1;
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identifier i,i1;
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position p;
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@@
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(
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c1 + c - 1
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c1@i1 +@p c@i
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)
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@s@
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constant r.c, r.c1;
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identifier i;
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expression e;
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@@
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(
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e | c@i
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e & c@i
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e |= c@i
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e &= c@i
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e | c1@i
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e & c1@i
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e |= c1@i
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e &= c1@i
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)
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@depends on s@
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position r.p;
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constant c1,c2;
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@@
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* c1 +@p c2
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@script:python depends on s && org@
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p << r.p;
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@@
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cocci.print_main("sum of probable bitmasks, consider |",p)
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@script:python depends on s && report@
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p << r.p;
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@@
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msg = "WARNING: sum of probable bitmasks, consider |"
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coccilib.report.print_report(p[0],msg)
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