On Wed, Dec 09, 2020 at 04:15:35PM -0800, Andrii Nakryiko wrote:
> On Wed, Dec 9, 2020 at 2:24 PM Seth Forshee <seth.fors...@canonical.com>
> wrote:
> >
> > Building the BPF selftests with clang 11, I'm getting the following
> > error:
> >
> > CLNG-LLC [test_maps] profiler1.o
> > In file included from progs/profiler1.c:6:
> > progs/profiler.inc.h:260:17: error: use of unknown builtin
> > '__builtin_preserve_enum_value' [-Wimplicit-function-declaration]
> > int cgrp_id = bpf_core_enum_value(enum
> > cgroup_subsys_id___local,
> > ^
> >
> > /home/ubuntu/unstable/tools/testing/selftests/bpf/tools/include/bpf/bpf_core_read.h:179:2:
> > note: expanded from macro 'bpf_core_enum_value'
> > __builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value,
> > BPF_ENUMVAL_VALUE)
> > ^
> > 1 error generated.
> > llc: error: llc: <stdin>:1:1: error: expected top-level entity
> > BPF obj compilation failed
>
> Addressed by fb3558127cb6 ("bpf: Fix selftest compilation on clang 11")
Great, thanks!
>
> >
> > I see that test_core_reloc_enumval.c takes precautions around the use of
> > __builtin_preserve_enum_value as it is currently only available in clang
> > 12 nightlies. Is it possible to do something similar here? Though I see
> > that the use of the builtin is not nearly so neatly localized as it is
> > in test_core_reloc_enumval.c.
> >
> > Thanks,
> > Seth
