[Xenomai] Won`t build on new Debian Stable

Henning Schild henning.schild at siemens.com
Fri Oct 13 11:16:19 CEST 2017


Am Fri, 13 Oct 2017 09:40:54 +0200
schrieb Norbert Lange <nolange79 at gmail.com>:

> Ok I just realized there is a "-Ur" option, aside from "-U -r".

In the docs of ld there is _only_ "-Ur", "-U" is not there and "-r" is
not in the docs of gcc. Also when looking at "--help -v".

Henning

> You get alot otherwise undocumented flags with "gcc --help -v" BTW
> 
> 2017-10-13 9:13 GMT+02:00 Norbert Lange <nolange79 at gmail.com>:
> > Hello,
> >
> > I tracked down the source of information to this:
> > https://wiki.ubuntu.com/SecurityTeam/PIE
> >
> > I changed the flags from "-Wl,-Ur" to "-Wl,-U -r", so you wont get
> > an explanation from me, why -U has to be passed for the linker.
> > And by the way, gcc accepts -U aswell, so this might be preferable
> > to be used directly too.
> >
> > I don`t know why those flags aren' t documented, bug in gcc
> > documentation? As far as I understand is that gcc is smart enough to
> > correctly deal with the flags gcc directly received, but the linker
> > lacks that information.
> >
> > I don' t know what the issue is with the C++ Constructors, in the
> > context of this change?
> > (I heard about the issues if those reside in a shared library, use
> > function from libcobald and don't depend on libcobald. Which is more
> > of a broken build to me if you don't add the depended libs, and will
> > bite you the same way if you use GCCs constructor attribute)
> >
> > Kind regards,
> > Norbert.
> >
> > 2017-10-12 10:33 GMT+02:00 Henning Schild
> > <henning.schild at siemens.com>:  
> >> Hey Norbert,
> >>
> >> thanks for looking into that again! Could you please explain how
> >> and why that works, or point out what to look at in flint? Mailing
> >> list thread, commit, something like that.
> >>
> >> As far as i can see gcc now gets a "-r" which i do not find in the
> >> manpage. And ld gets a "-U" which i do not find in its manpage. And
> >> there is something about c++ constructors which might change the
> >> behaviour of xenomai.
> >>
> >> Henning
> >>
> >> Am Tue, 10 Oct 2017 16:38:50 +0200
> >> schrieb Norbert Lange <nolange79 at gmail.com>:
> >>  
> >>> Some highly trivial fix attached!
> >>> Its strange that this flag is not documented in the manual (I
> >>> found out abaout this fix from
> >>> https://launchpad.net/ubuntu/+source/flint)
> >>>
> >>> Norbert Lange
> >>>
> >>> 2017-08-10 11:49 GMT+02:00 Henning Schild
> >>> <henning.schild at siemens.com>:  
> >>> > Hi Norbert,
> >>> >
> >>> > Thanks! In fact that issue has come up before and a similar
> >>> > workaround was described. It should be fixed, patches welcome!
> >>> >
> >>> > Henning
> >>> >
> >>> > Am Wed, 9 Aug 2017 16:21:02 +0200
> >>> > schrieb Norbert Lange <nolange79 at gmail.com>:
> >>> >  
> >>> >> Hello,
> >>> >>
> >>> >> Building the xenomai package won`t work because debian now
> >>> >> defaults to using pie, and the linker will complain with "ld:
> >>> >> -r and -pie may not be used together"
> >>> >>
> >>> >> A workaround for now is to add the flags manually:
> >>> >> ../xenomai-3.0.5/configure LDFLAGS=-no-pie CFLAGS="-fno-PIE
> >>> >> -fno-pie -no-pie"
> >>> >>
> >>> >> A real fix would be similar to
> >>> >> http://lists.gnu.org/archive/html/bug-grub/2016-11/msg00011.html
> >>> >> (no-pie is not supported on old and other compilers)
> >>> >>
> >>> >> Kind regards,
> >>> >> Norbert
> >>> >>
> >>> >> _______________________________________________
> >>> >> Xenomai mailing list
> >>> >> Xenomai at xenomai.org
> >>> >> https://xenomai.org/mailman/listinfo/xenomai  
> >>> >  
> >>  




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