On 9/24/19 8:26 AM, Shuah Khan wrote: > Hi Alexei and Daniel, > > bpf test doesn't build on Linux 5.4 mainline. Do you know what's > happening here. > > > make -C tools/testing/selftests/bpf/ > > -c progs/test_core_reloc_ptr_as_arr.c -o - || echo "clang failed") | \ > llc -march=bpf -mcpu=generic -filetype=obj -o > /mnt/data/lkml/linux_5.4/tools/testing/selftests/bpf/test_core_reloc_ptr_as_arr.o > > progs/test_core_reloc_ptr_as_arr.c:25:6: error: use of unknown builtin > '__builtin_preserve_access_index' [-Wimplicit-function-declaration] > if (BPF_CORE_READ(&out->a, &in[2].a)) > ^ > ./bpf_helpers.h:533:10: note: expanded from macro 'BPF_CORE_READ' > __builtin_preserve_access_index(src)) > ^ > progs/test_core_reloc_ptr_as_arr.c:25:6: warning: incompatible integer to > pointer conversion passing 'int' to parameter of type 'const void *' > [-Wint-conversion] > if (BPF_CORE_READ(&out->a, &in[2].a)) > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > ./bpf_helpers.h:533:10: note: expanded from macro 'BPF_CORE_READ' > __builtin_preserve_access_index(src)) > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > 1 warning and 1 error generated. > llc: error: llc: <stdin>:1:1: error: expected top-level entity > clang failed > > Also > > make TARGETS=bpf kselftest fails as well. Dependency between > tools/lib/bpf and the test. How can we avoid this type of > dependency or resolve it in a way it doesn't result in build > failures? Thanks, Shuah. The clang __builtin_preserve_access_index() intrinsic is introduced in LLVM9 (which just released last week) and the builtin and other CO-RE features are only supported in LLVM10 (current development branch) with more bug fixes and added features. I think we should do a feature test for llvm version and only enable these tests when llvm version >= 10. Andrii, what do you think? > > thanks, > -- Shuah
