On Tue, Jan 29, 2019 at 01:56:19PM +0100, Jakub Jelinek wrote: > On Tue, Jan 29, 2019 at 12:51:25PM +0000, Daniel P. Berrangé wrote: > > Libvirt has hit a problem with -Wjump-misses-init newly reporting bogus > > warnings for code using anonymous struct initializers during assignments: > > > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89061 > > https://bugzilla.redhat.com/show_bug.cgi?id=1669489 > > > > It is quite an ununfortunate bug as it is not straightforward to workaround > > the bogus warning by changing code, while we also don't want to disable > > -Wjump-misses-init since it is a useful/important warning in general. > > So we'd really like to see the regression fixed before F30 GA. > > That is not a false positive, you are crossing initialization of the > compound literal. Older GCC versions mistakenly haven't put the automatic > variables for the compound literals into the right scope. The variable was already initialized right at the start. The compound literal is just a short-hand for later changing the values in several fields of the struct at once. This is no different to manually assigning new values to each individual field one at a time. eg struct demo demo = {0}; ...some code with a goto... demo = (struct demo) { .cmd = "foo" }; is no different from struct demo demo = {0}; ...some code with a goto... demo.cmd = "foo" and neither should generate warnings about missing initializers with gotos. > Yes, in your case you are not accessing the compound literal in the cleanup: > code, but that is exactly the same case when you get a warning for: Even if we were accessing the the variable in the cleanup code, it would not be a missing initializer, as the variable was initialized at the time it was declared before any goto. > if (whatever) > goto cleanup; > > int i = 26; > > cleanup: > return 0; This is a completely different scenario, as it is jumping over the declaration of the variable and its only initializer. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
