Hello! I'm currently trying to solve a problem in LLVM which arises when building the compiler-rt library on 32-bit SPARC [1].
More specifically, I'm getting a linker error which indicates that the target does not 64-bit atomic operations natively and has to use libatomic: /usr/bin/ld: warning: -z gnu-version-script-compat ignored /usr/bin/ld: projects/compiler-rt/lib/sanitizer_common/CMakeFiles/RTSanitizerCommon.sparc.dir/sanitizer_libignore.cpp.o: in function `bool __sanitizer::atomic_compare_exchange_strong<__sanitizer::atomic_uint64_t>(__sanitizer::atomic_uint64_t volatile*, __sanitizer::atomic_uint64_t::Type*, __sanitizer::atomic_uint64_t::Type, __sanitizer::memory_order)': /var/lib/buildbot/workers/debian-stadler-sparc64/clang-sparc64-linux-multistage/llvm/compiler-rt/lib/sanitizer_common/sanitizer_atomic_clang.h:80: undefined reference to `__sync_val_compare_and_swap_8' While playing around with the compiler options trying to find a solution, I made an interesting discovery which is that GCC support 64-bit compare and swap on SPARCv8plus but not on 32-bit SPARCv9: glaubitz@gcc202:~$ echo | gcc -mv8plus -E -dM -|grep -i SWAP #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1 #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1 #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1 #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 1 glaubitz@gcc202:~$ echo | gcc -mcpu=v9 -m32 -E -dM -|grep -i SWAP #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 1 #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 1 #define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 1 glaubitz@gcc202:~$ Is this intentional? If yes, what is the exact difference between V8+ and 32-bit V9? Thanks, Adrian > [1] https://github.com/llvm/llvm-project/issues/53337 -- .''`. John Paul Adrian Glaubitz : :' : Debian Developer - glaub...@debian.org `. `' Freie Universitaet Berlin - glaub...@physik.fu-berlin.de `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
