catch useless conditionals like (1 == 1) or (1 != 0) - it seems like some code generators like this "style"
Signed-off-by: Nicholas Mc Guire <[email protected]> --- After stumbling across this code in drivers/media/dvb-frontends/dib7000p.c <snip> value = 0; if (1 != 0) value |= (1 << 6); if (ch->hierarchy == 1) value |= (1 << 4); if (1 == 1) value |= 1; switch ((ch->hierarchy == 0 || 1 == 1) ? ch->code_rate_HP : ch->code_rate_LP) { case FEC_2_3: <snip> It might be good to have a test for such conditions. If they can not be avoided they at least need to be commented as intentional This semantic patch only provides report mode as it is not generally possible to deduce a sound fix for such code. Tested with spatch version 1.0.0-rc23 on linux-3.19.0-rc4 which resulted in 12 findings in 6 files - none of which were false positives. scripts/coccinelle/tests/uselesscondition.cocci | 39 +++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 scripts/coccinelle/tests/uselesscondition.cocci diff --git a/scripts/coccinelle/tests/uselesscondition.cocci b/scripts/coccinelle/tests/uselesscondition.cocci new file mode 100644 index 0000000..50cff3a --- /dev/null +++ b/scripts/coccinelle/tests/uselesscondition.cocci @@ -0,0 +1,39 @@ +// Find conditions comparing two identical constants +// e.g 1 == 1 or 1 != 0 +// +// Some of these code sequences are due to code generators. +// Never the less they should be flagged and if not removed +// atleast commented. +virtual context +virtual org +virtual report + +@condeq@ +constant C; +position p; +@@ + +<+... +( +* C@p == C +| +* C@p != C +| +* C@p <= C +| +* C@p < C +) +...+> + +@script:python depends on org@ +p << condeq.p; +@@ + +cocci.print_main("bad/useless conditional",p) + +@script:python depends on report@ +p << condeq.p; +@@ + +msg = "bad/useless conditional line %s" % (p[0].line) +coccilib.report.print_report(p[0],msg) -- 1.7.10.4 _______________________________________________ Cocci mailing list [email protected] https://systeme.lip6.fr/mailman/listinfo/cocci
