Re: [PATCH bpf-next 5/6] selftests/bpf: replace test_progs and test_maps w/ general rule

[Alexei Starovoitov <ast@fb.com>]

On 10/15/19 3:03 PM, Andrii Nakryiko wrote:
> Define test runner generation meta-rule that codifies dependencies
> between test runner, its tests, and its dependent BPF programs. Use that
> for defining test_progs and test_maps test-runners. Also additionally define
> 3 flavors of test_progs:
> - alu32, which builds BPF programs with 32-bit registers codegen;
> - bpf_gcc, which build BPF programs using GCC, if it supports BPF target;
> - native, which uses a mix of native Clang target and BPF target for LLC.

Great improvement, but it's taking it too far.
(clang  -I. -I/data/users/ast/net-next/tools/testing/selftests/bpf -g 
-D__TARGET_ARCH_x86 -I. -I./include/uapi 
-I/data/users/ast/net-next/tools/include/uapi 
-I/data/users/ast/net-next/tools/lib/bpf 
-I/data/users/ast/net-next/tools/testing/selftests/usr/include 
-idirafter /usr/local/include -idirafter 
/data/users/ast/llvm/bld/lib/clang/10.0.0/include -idirafter 
/usr/include -Wno-compare-distinct-pointer-types -O2 -emit-llvm -c 
progs/test_core_reloc_existence.c -o - || echo "BPF obj compilation 
failed") | llc -march=bpf -mcpu=probe   -filetype=obj -o 
/data/users/ast/net-next/tools/testing/selftests/bpf/native/test_core_reloc_existence.o
progs/test_core_reloc_existence.c:47:18: error: use of unknown builtin 
'__builtin_preserve_field_info' [-Wimplicit-function-declaration]
         out->a_exists = bpf_core_field_exists(in->a);

native clang + llc is useful for old school tracing only (before CO-RE).