Re: ANNOUNCE: pahole v1.23 (BTF tags and alignment inference)

[Andrii Nakryiko]

On Wed, Dec 8, 2021 at 10:37 AM Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> wrote:
>
> Em Wed, Dec 08, 2021 at 03:35:36PM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Wed, Dec 08, 2021 at 03:26:31PM +0100, Jan Engelhardt escreveu:
> > > On Wednesday 2021-12-08 14:54, Arnaldo Carvalho de Melo wrote:
> > > >   The v1.23 release of pahole and its friends is out, this time
> > > >the main new features are the ability to encode BTF tags, to carry
> > >
> > > [    7s] /home/abuild/rpmbuild/BUILD/dwarves-1.23/btf_encoder.c:145:10: error: 'BTF_KIND_DECL_TAG' undeclared here (not in a function); did you mean 'BTF_KIND_FLOAT'?
>
> > > libbpf-0.5.0 is present, since CMakeLists.txt checked for >= 0.4.0.
>
> > My fault, knowing the flux that libbpf is in getting to 1.0 I should
> > have retested with the perf tools container based tests.
>
> > Can you think about some fix for that? Lemme see if BTF_KIND_DECL_TAG is
> > a define or an enum...
>
> enum {
>         BTF_KIND_UNKN           = 0,    /* Unknown      */
>         BTF_KIND_INT            = 1,    /* Integer      */
>         BTF_KIND_PTR            = 2,    /* Pointer      */
>         BTF_KIND_ARRAY          = 3,    /* Array        */
>         BTF_KIND_STRUCT         = 4,    /* Struct       */
>         BTF_KIND_UNION          = 5,    /* Union        */
>         BTF_KIND_ENUM           = 6,    /* Enumeration  */
>         BTF_KIND_FWD            = 7,    /* Forward      */
>         BTF_KIND_TYPEDEF        = 8,    /* Typedef      */
>         BTF_KIND_VOLATILE       = 9,    /* Volatile     */
>         BTF_KIND_CONST          = 10,   /* Const        */
>         BTF_KIND_RESTRICT       = 11,   /* Restrict     */
>         BTF_KIND_FUNC           = 12,   /* Function     */
>         BTF_KIND_FUNC_PROTO     = 13,   /* Function Proto       */
>         BTF_KIND_VAR            = 14,   /* Variable     */
>         BTF_KIND_DATASEC        = 15,   /* Section      */
>         BTF_KIND_FLOAT          = 16,   /* Floating point       */
>         BTF_KIND_DECL_TAG       = 17,   /* Decl Tag */
>         BTF_KIND_TYPE_TAG       = 18,   /* Type Tag */
>
>         NR_BTF_KINDS,
>         BTF_KIND_MAX            = NR_BTF_KINDS - 1,
> };
>
> Do you guys have any plans on updating libbpf?
>

In what sense? It's already updated and knows about all those new KINDS ([0])

  [0] https://github.com/libbpf/libbpf/blob/3ef05a585efd47abf4dc92265430d0248d7f388a/src/btf.c#L302

> - Arnaldo