[systemd-devel] [PATCH] Fix a few compiler warnings

[Djalal Harouni]

On Wed, May 21, 2014 at 10:46:21AM +0200, Lennart Poettering wrote:
> On Wed, 21.05.14 10:29, Thomas H.P. Andersen (phomes at gmail.com) wrote:
> 
> > 
> > On Tue, May 20, 2014 at 5:43 PM, Lennart Poettering
> > <lennart at poettering.net> wrote:
> > > On Mon, 19.05.14 19:52, Tom Gundersen (teg at jklm.no) wrote:
> > >
> > >> >  _public_ int sd_peer_get_session(int fd, char **session) {
> > >> > -        struct ucred ucred;
> > >> > +        struct ucred ucred = {};
> > >>
> > >> I can't reproduce this warning, but more importantly, why is this
> > >> necessary in this function and not the subsequent noes (which all seem
> > >> to be more or less equivalent)?
> > >
> > > Hmm, given the current flakiness of the gcc warnings when -flto is in
> > > the mix I think we should follow the rule that we do not fix gcc
> > > warnings that show up only with -flto is used. We can revisit that in a
> > > few years when LTO has settled a bit, but for now I am pretty sure
> > > trying to fix all those issues is a waste of time and certainly don't
> > > improve our code...
> > >
> > > Cristian, are those warnings you saw related to -flto?
> > 
> > The warning in namespace_open is not related to LTO. It shows up with
> > "autogen.sh g && make" and that gets in the way for my workflow. It
> > would make my life easier if we could silence it with the fix in this
> > patch or suppress it with
> > #pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
> > 
> > Would that be okay?
> 
> Ok, fixed that one. It is a false positive, but I can see why gcc gets
> confused, and this sounds OK to fix. Have done so now. Please test!
Yes, thank you! I was spammed with reports of namespace_open due to
optimization flags and later by the LTO on that function each time its
unit is involved in linking.

There is also this one genrated by LTO, IMO it's a false positive since
we do *check* for "lease" but the code is not consistent since in that
code path, "lease" is initialized to NULL in other places, except for
this one:

src/resolve/resolved-manager.c: In function 'manager_update_resolv_conf':
src/libsystemd-network/sd-dhcp-lease.c:67:18: warning: 'lease' may be used uninitialized in this function [-Wmaybe-uninitialized]
	if (lease->dns_size) {
		 ^
src/network/sd-network.c:146:24: note: 'lease' was declared here
	sd_dhcp_lease *lease;
		       ^

Thanks!

-- 
Djalal Harouni
http://opendz.org