21 Nov
2017
21 Nov
'17
8:19 a.m.
On Tue, Nov 21, 2017 at 03:06:24AM +0100, Neels Hofmeyr wrote:
Now I'm confused. Why does a lack of -O2 break a
linkage.
because it removes dead code.
It's not the osmo-hnbgw linkage per se that seems
to be the cause. I can link
that last step with or without -O2 successfully. It must be a combination of
building a depending library without -O2 and then linking that to osmo-iuh.
I diffed the entire build log between a succeeding and a failing build of
osmo-iuh, and really the only difference everywhere is that the succeeding
build uses -O2 everywhere.
The only differences in config.log are the same: most conftest programs have
-O2 removed, few have a -g added. The conftest conclusions are all identical.
My big question now is: sctp_send() is actually called
from hnbgw.c directly.
this is the big surprise here, as this shouldn't be the case ever we introduced
libosmo-sigtran.
So IIUC, we should in fact be required to pass -lsctp
to the linker for
osmo-hnbgw. If that is correct, how am I allowed to skip that by passing -O2?
Because the call to sctp_send() is in dead code, specifically in a
static function that the compiler will drop during optimziation. Hence
the offending symbol reference is gone at the time of linking if any -O
is used.
In I8d52b11e3f476ffd77f3ab185b679817cd3b2163 I introduce the -Wall and
then in subseqent Ifbcb21d43e17bf512bc7b219e590410e06c434ca I remove it.
There's also an interesting catch in I9dbad21e75a55ad91b12d3d3ee8bd6dfb5326c3e
and plenty of warnings fixes in c7a158211fa59ac27c70faa0813a27e2f3a7a569
--
- Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/
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