Segfault on exit with GCC 6.3.0 Release Builds

[Tino]

I noticed this problem on my system when upgrading to GCC 6.3.0 in January and now Appveyor shows the same:

When doing Release builds and optimizing with -O3, widelands itself and the economy_test do segfault on exit.
Debug builds or release builds done with -O2 are fine.

I am not sure if this is only MinGW64 GCC 6.3.0 on Windows or it also affects other platforms. Travis does still use GCC 6.2.0 as far as i can see.

[Hans Joachim Desserud (hjd)]

I did a brief test with Ubuntu Zesty (the current development version), which from what I can see used GCC 6.3.0 to build the PPA build [1]:

>The CXX compiler identification is GNU 6.3.0

The tests ran ok, and I didn't have any problems with closing Widelands after installing the package in a vm. (Ok, strictly speaking it complained about waiting 5 minutes to close audio and that Widelands had to be killed manually but a) I believe this to be unrelated (?) and b) strongly suspect it is due to running in a vm.

I can double-check a bit by building a release manually though ;)

[1] https://code.launchpad.net/~widelands-dev/+recipe/widelands-daily, more specifically https://code.launchpad.net/~widelands-dev/+archive/ubuntu/widelands-daily/+build/12062131/+files/buildlog_ubuntu-zesty-amd64.widelands_1%3A19-ppa0-bzr8307-201702271132~ubuntu17.04.1_BUILDING.txt.gz

[Tino (tino79)]

Ok, so probably only a bug/problem with mingw64 on windows. Wouldn't be the first time...

I've found a nice article on optimization [1], which states:

  -O3: the highest level of optimization possible. It enables optimizations that are expensive in terms of compile time and memory usage. Compiling with -O3 is not a guaranteed way to improve performance, and in fact, in many cases, can slow down a system due to larger binaries and increased memory usage. -O3 is also known to break several packages. Using -O3 is not recommended.

Perhaps switching to O2 for widelands in general would be a safe solution? Has anyone ever tested, if widelands actually profits from O3 (filesize/compiletime/runtime fps or cpu usage)?

[1] https://wiki.gentoo.org/wiki/GCC_optimization

[GunChleoc (gunchleoc)]

Size of the build directory:

With -02: 173.4 MB

With -03: 175.9 MB

Compiler version: gcc (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609

So, it's slightly bigger for me with -03.

My machine is too slow to do anything meaningful with Valgrind, so I'll leave those tests to somebody else.

[Jukka Pakarinen (flegu)]

I did a release build from revision 8467 with -03 flag and gcc (Debian 6.3.0-18) 6.3.0 20170516. After that I ran regression_test.py without any problems. I played "Basic Control" tutorial few moments and exited from the game without segfalt or any other problems. Then I player the same tutorial with Valgrind. There was some memory leaks while the game was starting up but after that everything went fine.

[GunChleoc (gunchleoc)]

Thanks for testing!

Do you still have any info on the memory leaks for a new bug? We'd be interested in fixing those.

[Jukka Pakarinen (flegu)]

I only started the game and pressed "Exit Widelands". The attachment includes Valgrind log from Debug build. I compared Debug and Release results and the both seems to have same memory leaks.

[GunChleoc (gunchleoc)]

Fixed in build20-rc1