[regression in 0.2.1.6] relocation R_X86_64_PC32 cannot be used against symbol __stack_chk_guard; recompile with -fPIC

[yurivict]

ld: error: relocation R_X86_64_PC32 cannot be used against symbol __stack_chk_guard; recompile with -fPIC
>>> defined in /lib/libc.so.7
>>> referenced by AutoTime.cpp
>>>               CMakeFiles/MNNCore.dir/source/core/AutoTime.cpp.o:(MNN::Timer::Timer())

ld: error: relocation R_X86_64_PC32 cannot be used against symbol __stack_chk_guard; recompile with -fPIC
>>> defined in /lib/libc.so.7
>>> referenced by AutoTime.cpp
>>>               CMakeFiles/MNNCore.dir/source/core/AutoTime.cpp.o:(MNN::Timer::Timer())

clang-8

FreeBSD 12

[Naville]

-fPIC is indeeded added in our CMakeLists and MNN builds without any issue on our Ubuntu CI so I'm a bit confused about what's going on here. Any more context? output of initial cmake configuration or better yet, a full build log would do.

Also please consider using #549 instead so I could track issues better

[yurivict]

-fPIC is missing in some command lines. Adding it to CXXFLAGS and CFLAGS environment variables solved the problem.

[Naville]

Right. Unless I'm missing something here, CMakeLists.txt#L173 already sets this flag. And consider this line is above any other target is created/imported, this should have effect on all targets created by CMake.

Are you sure CMAKE_SYSTEM_NAME is Linux on FreeBSD?

[Naville]

So CMAKE_SYSTEM_NAME is FreeBSD on FreeBSD which breaks that part of the logic. This was never discovered in previous versions because the old CMakeLists.txt was passing -fPIC everywhere. This should be fixable in our next release

[yurivict]

No, on FreeBSD CMAKE_SYSTEM_NAME=FreeBSD