Build on PowerPC breaks at linking stage

[kkostyan]

I try to build i2pd 0.10.0 for powerpc 32bit arch

# lscpu
Architecture:          ppc
CPU op-mode(s):        32-bit
Byte Order:            Big Endian

and it stops at linking stage with following message:

Linking CXX executable ../i2pd
../libi2pd-core.a(Transports.cpp.o): In function `i2p::transport::Transports::UpdateBandwidth()':
Transports.cpp:(.text+0x234): undefined reference to `__atomic_load_8'
Transports.cpp:(.text+0x248): undefined reference to `__atomic_load_8'
Transports.cpp:(.text+0x298): undefined reference to `__atomic_load_8'
Transports.cpp:(.text+0x2dc): undefined reference to `__atomic_load_8'
../libi2pd-core.a(NTCPSession.cpp.o): In function `i2p::transport::NTCPSession::HandleReceived(boost::system::error_code const&, unsigned int)':
NTCPSession.cpp:(.text+0x3d90): undefined reference to `__atomic_fetch_add_8'
../libi2pd-core.a(NTCPSession.cpp.o): In function `i2p::transport::NTCPSession::HandleSent(boost::system::error_code const&, unsigned int, std::vector<std::shared_ptr<i2p::I2NPMessage>, std::allocator<std::shared_ptr<i2p::I2NPMessage> > >)':
NTCPSession.cpp:(.text+0x894c): undefined reference to `__atomic_fetch_add_8'
../libi2pd-core.a(SSUSession.cpp.o): In function `i2p::transport::SSUSession::Send(unsigned char const*, unsigned int)':
SSUSession.cpp:(.text+0x344): undefined reference to `__atomic_fetch_add_8'
../libi2pd-core.a(SSUSession.cpp.o): In function `i2p::transport::SSUSession::ProcessNextMessage(unsigned char*, unsigned int, boost::asio::ip::basic_endpoint<boost::asio::ip::udp> const&)':
SSUSession.cpp:(.text+0x6420): undefined reference to `__atomic_fetch_add_8'
collect2: error: ld returned 1 exit status
client/CMakeFiles/i2pd-client.dir/build.make:396: ошибка выполнения рецепта для цели «i2pd»
make[2]: *** [i2pd] Ошибка 1
CMakeFiles/Makefile2:142: ошибка выполнения рецепта для цели «client/CMakeFiles/i2pd-client.dir/all»
make[1]: *** [client/CMakeFiles/i2pd-client.dir/all] Ошибка 2
Makefile:117: ошибка выполнения рецепта для цели «all»
make: *** [all] Ошибка 2

adding -latomic to linker flags solves this problem.

Linking CXX executable ../i2pd
[100%] Built target i2pd-client

Could you add checking if arch supports __atomic_load_8 or __atomic_fetch_add_8 function, and link to libatomic if not.

[orignal]

Linux or Mac OS X?

[mlt]

It might help if you could pastebin your ./CMakeFiles//CMakeCXXCompiler.cmake and post a link here or mail it. I wonder if we can narrow it down to platform and/or compiler maybe just check CMAKE_CXX_COMPILER_ID for (Apple)Clang.

[orignal]

I doubt if there is clang for Mac OS X PPC since last one is 10.4

[kkostyan]

This is a Linux box running Debian 8.0 / Linux 2.6.32.
The contets of CMakeCXXCompiler.cmake could be found at http://pastebin.com/F3BANaed

[mlt]

@kkostyan Do you think it would work otherwise? Like checking for libatomic presence and it having that function and linking against it? It seems like that's what I saw in llvm patch check_library_exists(atomic __atomic_fetch_add_4 "" HAVE_LIBATOMIC). I would assume there is no libatomic on platforms having it natively so it is probably safe.

[majestrate]

i had a similar problem when building for MIPS, temp solution was to add -latomic to link flags.

[barracuda156]

Trying to make it work for Darwin PPC: #1726 (comment)