| Message ID | 20171221042236.1667-1-andrew.gregory.8@gmail.com |
|---|---|
| State | Accepted, archived |
| Headers | show |
On 21/12/17 14:22, Andrew Gregory wrote: > 6cfc4757b98e813428d261dbc185e20618ca83a6 was overzealous in attempting > to optimize away a call to strcmp based on a comparison of hashes. The > call can be skipped if the hashes are different, but different strings > could have the same hash. > > Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com> > --- Good catch! I'm interest if you saw an issue in the wild? A
On 01/06/18 at 01:36pm, Allan McRae wrote: > On 21/12/17 14:22, Andrew Gregory wrote: > > 6cfc4757b98e813428d261dbc185e20618ca83a6 was overzealous in attempting > > to optimize away a call to strcmp based on a comparison of hashes. The > > call can be skipped if the hashes are different, but different strings > > could have the same hash. > > > > Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com> > > --- > > Good catch! I'm interest if you saw an issue in the wild? > > A Nope, just noticed it as I was looking through the deps code. apg
diff --git a/lib/libalpm/deps.c b/lib/libalpm/deps.c index 96f91739..3d3f8ef2 100644 --- a/lib/libalpm/deps.c +++ b/lib/libalpm/deps.c @@ -698,10 +698,8 @@ static alpm_pkg_t *resolvedep(alpm_handle_t *handle, alpm_depend_t *dep, } for(j = _alpm_db_get_pkgcache(db); j; j = j->next) { alpm_pkg_t *pkg = j->data; - /* with hash != hash, we can even skip the strcmp() as we know they can't - * possibly be the same string */ - if(pkg->name_hash != dep->name_hash && _alpm_depcmp(pkg, dep) - && !alpm_pkg_find(excluding, pkg->name)) { + if((pkg->name_hash != dep->name_hash || strcmp(pkg->name, dep->name) != 0) + && _alpm_depcmp(pkg, dep) && !alpm_pkg_find(excluding, pkg->name)) { if(alpm_pkg_should_ignore(handle, pkg)) { alpm_question_install_ignorepkg_t question = { .type = ALPM_QUESTION_INSTALL_IGNOREPKG,
6cfc4757b98e813428d261dbc185e20618ca83a6 was overzealous in attempting to optimize away a call to strcmp based on a comparison of hashes. The call can be skipped if the hashes are different, but different strings could have the same hash. Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com> --- lib/libalpm/deps.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)