Re: [PATCH bpf-next 1/7] libbpf: disable -Wswitch-enum compiler warning

[Andrii Nakryiko <andrii.nakryiko@gmail.com>]

On Tue, Aug 18, 2020 at 6:23 PM Yonghong Song <yhs@fb.com> wrote:
>
>
>
> On 8/18/20 2:33 PM, Andrii Nakryiko wrote:
> > That compilation warning is more annoying, than helpful.
>
> Curious which compiler and which version caused this issue?
> I did not hit with gcc 8.2 or latest clang in my environment.
>

Strange, I just tried on bpf-next, removed -Wno-switch-enum and got
tons of errors:

libbpf.c: In function ‘bpf_object__sanitize_prog’:
libbpf.c:5560:3: error: enumeration value ‘BPF_FUNC_unspec’ not
handled in switch [-Werror=switch-enum]
   switch (func_id) {
   ^~~~~~
libbpf.c:5560:3: error: enumeration value ‘BPF_FUNC_map_lookup_elem’
not handled in switch [-Werror=switch-enum]
libbpf.c:5560:3: error: enumeration value ‘BPF_FUNC_map_update_elem’
not handled in switch [-Werror=switch-enum]
... and many more ...

My compiler:

$ cc --version
cc (GCC) 8.2.1 20180801 (Red Hat 8.2.1-2)


> >
> > Signed-off-by: Andrii Nakryiko <andriin@fb.com>
> > ---
> >   tools/lib/bpf/Makefile | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
> > index bf8ed134cb8a..95c946e94ca5 100644
> > --- a/tools/lib/bpf/Makefile
> > +++ b/tools/lib/bpf/Makefile
> > @@ -107,7 +107,7 @@ ifeq ($(feature-reallocarray), 0)
> >   endif
> >
> >   # Append required CFLAGS
> > -override CFLAGS += $(EXTRA_WARNINGS)
> > +override CFLAGS += $(EXTRA_WARNINGS) -Wno-switch-enum
> >   override CFLAGS += -Werror -Wall
> >   override CFLAGS += -fPIC
> >   override CFLAGS += $(INCLUDES)
> >