Messages in this thread | | | Date | Thu, 20 Aug 2020 10:33:33 +0200 (CEST) | From | Julia Lawall <> | Subject | Re: [Cocci] coccinelle: Convert comma to semicolons (was Re: [PATCH] checkpatch: Add test for comma use that should be semicolon) |
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On Wed, 19 Aug 2020, Joe Perches wrote:
> On Wed, 2020-08-19 at 14:22 -0700, Joe Perches wrote: > > There are commas used as statement terminations that should typically > > have used semicolons instead. Only direct assignments or use of a single > > function or value on a single line are detected by this test. > > > > e.g.: > > foo = bar(), /* typical use is semicolon not comma */ > > bar = baz(); > > > > Add an imperfect test to detect these comma uses. > > > > No false positives were found in testing, but many types of false negatives > > are possible. > > > > e.g.: > > foo = bar() + 1, /* comma use, but not direct assignment */ > > bar = baz(); > > Hi. > > I recently added a test for this condition to linux's checkpatch. > > A similar coccinelle script might be: > > $ cat comma.cocci > @@ > expression e1; > expression e2; > @@ > > e1 > - , > + ; > e2; > $ > > This works reasonably well but it has several false positives > for declarations like: > > $ spatch --sp-file comma.cocci mm/huge_memory.c > diff -u -p a/huge_memory.c b/huge_memory.c > --- a/huge_memory.c > +++ b/huge_memory.c > @@ -2778,7 +2778,7 @@ static unsigned long deferred_split_scan > struct pglist_data *pgdata = NODE_DATA(sc->nid); > struct deferred_split *ds_queue = &pgdata->deferred_split_queue; > unsigned long flags; > - LIST_HEAD(list), *pos, *next; > + LIST_HEAD(list), *pos; *next; > struct page *page; > int split = 0; > $ > > Any script improvement suggestions?
I have a bunch of variations of this that are more complicated than I would have expected. One shorter variant that I have is:
@@ expression e1,e2; statement S; @@
S e1 -, +; (<+... e2 ...+>);
This will miss cases where the first statement is the comma thing. But I think it is possible to improve this now. I will check.
thanks, julia
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