[PATCH] silence gcc array-bounds warning
- From
Jeff King <peff@peff.net>
- Date
- Oct 24, 2013, 08:45 UTC
- Message-ID
- <20131024084513.GA582@sigill.intra.peff.net>
In shorten_unambiguous_ref, we build and cache a reverse-map of the rev-parse rules like this:
static char **scanf_fmts;
static int nr_rules;
if (!nr_rules) {
for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
... generate scanf_fmts ...
}where ref_rev_parse_rules is terminated with a NULL pointer. Compiling with "gcc -O2 -Wall" does not cause any problems, but compiling with "-O3 -Wall" generates:
$ make CFLAGS='-O3 -Wall' refs.o
refs.c: In function ‘shorten_unambiguous_ref’:
refs.c:3379:29: warning: array subscript is above array bounds [-Warray-bounds]
for (; ref_rev_parse_rules[nr_rules]; nr_rules++)Curiously, we can silence this by explicitly nr_rules to 0 in the beginning of the loop, even though the compiler should be able to tell that we follow this code path only when nr_rules is already 0.
Signed-off-by: Jeff King <peff@peff.net> --- This is a repost of:
http://article.gmane.org/gmane.comp.version-control.git/235703
which contains a little more cover-letter discussion.
refs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/refs.c b/refs.c index 3710748..0c0e963 100644 --- a/refs.c +++ b/refs.c @@ -3376,7 +3376,7 @@ char *shorten_unambiguous_ref(const char *refname, int strict) size_t total_len = 0; /* the rule list is NULL terminated, count them first */ - for (; ref_rev_parse_rules[nr_rules]; nr_rules++) + for (nr_rules = 0; ref_rev_parse_rules[nr_rules]; nr_rules++) /* no +1 because strlen("%s") < strlen("%.*s") */ total_len += strlen(ref_rev_parse_rules[nr_rules]);
-- 1.8.4.1.898.g8bf8a41.dirty