2017-06-27 6:47 GMT+02:00 David Kastrup <d...@gnu.org>: > Thomas Morley <thomasmorle...@gmail.com> writes: > >> Hi all, >> >> in the german forum a user reported a segfault. >> >> If you understand german please read: >> https://lilypondforum.de/index.php/topic,70.0.html >> It's too much to refer here in all details. >> >> In short: >> He tried to compile >> horn.ly from >> www.mutopiaproject.org/ftp/MozartWA/KV447/MozartHornConcerto3/MozartHornConcerto3-lys.zip >> with 2.18.2 which he got via apt-get from Debian 9.0 testing, "buster" i386 >> Logs under the link above in the german forum >> >> In the light of >> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=746005#278 >> I'd recommend someone more skilled than me could have a look. > > Pretty sure this would be > > commit b0dce76daf27721ba157cd2ac5d7662d4c8d75f8 > Author: Guido Aulisi <guido.aul...@gmail.com> > Date: Fri Jul 22 15:26:29 2016 +0200 > > Issue 4814: grob.cc segfaults with gcc6 > > From the release notes of GCC 6: > > Optimizations remove null pointer checks for this > > When optimizing, GCC now assumes the this pointer can never be null, > which is guaranteed by the language rules. Invalid programs which > assume it is OK to invoke a member function through a null > pointer (possibly relying on checks like this != NULL) may crash or > otherwise fail at run time if null pointer checks are optimized > away. With the -Wnull-dereference option the compiler tries to warn > when it detects such invalid code. > > If the program cannot be fixed to remove the undefined behavior then > the option -fno-delete-null-pointer-checks can be used to disable > this optimization. That option also disables other optimizations > involving pointers, not only those involving this. > > As a consequence, we cannot call a member function on a prospective null > pointer (which actually is a bad idea for a number of other reasons, > like when anything tries accessing the vtable) and then try sorting out > the condition in the routine itself. > > This problem was first observed with Fedora 24. The Ubuntu GCC6 > prerelease does not show this problem; presumably the respective > optimization has been disabled in the Ubuntu/Debian packaging because of > affecting other programs. > > Commit-message-by: David Kastrup <d...@gnu.org> > Signed-off-by: David Kastrup <d...@gnu.org> > > > -- > David Kastrup
Do I understand correctly, 2.18.2 as distrubuted by debian 9 testing is mostly unusable? And they should apply the patch for 4814? Cheers, Harm _______________________________________________ lilypond-devel mailing list lilypond-devel@gnu.org https://lists.gnu.org/mailman/listinfo/lilypond-devel
