On Mon, Mar 6, 2023 at 9:56 PM Ian Rogers <irogers@xxxxxxxxxx> wrote: > > On Mon, Mar 6, 2023 at 8:43 PM Namhyung Kim <namhyung@xxxxxxxxxx> wrote: > > > > Hi Ian, > > > > On Mon, Mar 6, 2023 at 7:21 PM Ian Rogers <irogers@xxxxxxxxxx> wrote: > > > > > > __has_builtin was passed the macro rather than the actual builtin > > > feature. > > > > Oh, I missed it's a macro define in tools/lib/bpf/bpf_core_read.h file. > > > > Looking at some BPF test codes, it seems you also need to check the > > clang compiler version. Please take a look at the file below: > > > > tools/testing/selftests/bpf/progs/test_core_reloc_type_base.c > > > > Thanks, > > Namhyung > > Hmm.. > > tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c: > ... > /* Support for the BPF_TYPE_MATCHES argument to the > * __builtin_preserve_type_info builtin was added at some point during > * development of clang 15 and it's what we require for this test. > */ > #if __has_builtin(__builtin_preserve_type_info) && __clang_major__ >= 15 > ... > > I'm not sure we need to worry about development clang builds and just > the __has_builtin is cleaner. Perhaps the BPF folks can chime in. My understanding is that __builtin_preserve_type_info is supported before. But clang 15 added BPF_TYPE_MATCHES which is used for bpf_core_type_matches(). So just checking the builtin would not work. Thanks, Namhyung
