Re: [PATCH bpf-next 3/6] selftests/bpf: add non-standardly sized enum tests for btf_dump

[Eduard Zingerman <eddyz87@gmail.com>]

On Mon, 2022-12-12 at 10:45 -0800, Andrii Nakryiko wrote:
> On Fri, Dec 9, 2022 at 9:32 AM Eduard Zingerman <eddyz87@gmail.com> wrote:
> > 
> > On Thu, 2022-12-08 at 10:57 -0800, Andrii Nakryiko wrote:
> > > Add few custom enum definitions testing mode(byte) and mode(word)
> > > attributes.
> > > 
> > > Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
> > > ---
> > >  .../bpf/progs/btf_dump_test_case_syntax.c     | 36 +++++++++++++++++++
> > >  1 file changed, 36 insertions(+)
> > > 
> > > diff --git a/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c b/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c
> > > index 4ee4748133fe..26fffb02ed10 100644
> > > --- a/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c
> > > +++ b/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c
> > > @@ -25,6 +25,39 @@ typedef enum {
> > >       H = 2,
> > >  } e3_t;
> > > 
> > > +/* ----- START-EXPECTED-OUTPUT ----- */
> > > +/*
> > > + *enum e_byte {
> > > + *   EBYTE_1 = 0,
> > > + *   EBYTE_2 = 1,
> > > + *} __attribute__((mode(byte)));
> > > + *
> > > + */
> > > +/* ----- END-EXPECTED-OUTPUT ----- */
> > > +enum e_byte {
> > > +     EBYTE_1,
> > > +     EBYTE_2,
> > > +} __attribute__((mode(byte)));
> > > +
> > > +/* ----- START-EXPECTED-OUTPUT ----- */
> > > +/*
> > > + *enum e_word {
> > > + *   EWORD_1 = 0LL,
> > > + *   EWORD_2 = 1LL,
> > > + *} __attribute__((mode(word)));
> > > + *
> > > + */
> > > +/* ----- END-EXPECTED-OUTPUT ----- */
> > > +enum e_word {
> > > +     EWORD_1,
> > > +     EWORD_2,
> > > +} __attribute__((mode(word))); /* force to use 8-byte backing for this enum */
> > > +
> > > +/* ----- START-EXPECTED-OUTPUT ----- */
> > > +enum e_big {
> > > +     EBIG_1 = 1000000000000ULL,
> > > +};
> > > +
> > >  typedef int int_t;
> > > 
> > 
> > Something is off with this test, when executed on my little-endian
> > machine the output looks as follows:
> > 
> > # ./test_progs -n 23/1
> > --- -   2022-12-09 17:22:03.412602033 +0000
> > +++ /tmp/btf_dump_test_case_syntax.output.Z28uhX        2022-12-09 17:22:03.403945082 +0000
> > @@ -23,13 +23,13 @@
> >  } __attribute__((mode(byte)));
> > 
> >  enum e_word {
> > -       EWORD_1 = 0LL,
> > -       EWORD_2 = 1LL,
> > +       EWORD_1 = 0,
> > +       EWORD_2 = 1,
> >  } __attribute__((mode(word)));
> > 
> >  enum e_big {
> > -       EBIG_1 = 1000000000000ULL,
> > -};
> > +       EBIG_1 = 3567587328,
> > +} __attribute__((mode(word)));
> > 
> 
> You seem to have too old Clang which doesn't emit ENUM64 types, try upgrading?

My apologies, you are correct.

> 
> 
> > But this is not related to your changes, here is a raw dump:
> > 
> > $ bpftool btf dump file ./btf_dump_test_case_syntax.bpf.o
> > 
> > [10] ENUM 'e_big' encoding=UNSIGNED size=8 vlen=1
> >         'EBIG_1' val=3567587328
> > 
> > >  typedef volatile const int * volatile const crazy_ptr_t;
> > > @@ -224,6 +257,9 @@ struct root_struct {
> > >       enum e2 _2;
> > >       e2_t _2_1;
> > >       e3_t _2_2;
> > > +     enum e_byte _100;
> > > +     enum e_word _101;
> > > +     enum e_big _102;
> > >       struct struct_w_typedefs _3;
> > >       anon_struct_t _7;
> > >       struct struct_fwd *_8;
> >