On Fri, Dec 13, 2019 at 02:32:04PM -0800, Andrii Nakryiko wrote:
> Expose API that allows to emit type declaration and field/variable definition
> (if optional field name is specified) in valid C syntax for any provided BTF
> type. This is going to be used by bpftool when emitting data section layout as
> a struct. As part of making this API useful in a stand-alone fashion, move
> initialization of some of the internal btf_dump state to earlier phase.
>
> Acked-by: Martin KaFai Lau <kafai@xxxxxx>
> Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
> ---
> tools/lib/bpf/btf.h | 22 ++++++++++++++
> tools/lib/bpf/btf_dump.c | 62 +++++++++++++++++++++++-----------------
> tools/lib/bpf/libbpf.map | 1 +
> 3 files changed, 59 insertions(+), 26 deletions(-)
>
> diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
> index a114c8ef4f08..1f9625946ead 100644
> --- a/tools/lib/bpf/btf.h
> +++ b/tools/lib/bpf/btf.h
> @@ -126,6 +126,28 @@ LIBBPF_API void btf_dump__free(struct btf_dump *d);
>
> LIBBPF_API int btf_dump__dump_type(struct btf_dump *d, __u32 id);
>
> +struct btf_dump_emit_type_decl_opts {
> + /* size of this struct, for forward/backward compatiblity */
> + size_t sz;
> + /* optional field name for type declaration, e.g.:
> + * - struct my_struct <FNAME>
> + * - void (*<FNAME>)(int)
> + * - char (*<FNAME>)[123]
> + */
> + const char *field_name;
> + /* extra indentation level (in number of tabs) to emit for multi-line
> + * type declarations (e.g., anonymous struct); applies for lines
> + * starting from the second one (first line is assumed to have
> + * necessary indentation already
> + */
> + int indent_level;
> +};
> +#define btf_dump_emit_type_decl_opts__last_field attach_prog_fd
OPTS_VALID() is missing in btf_dump__emit_type_decl() ?
Otherwise it would have caught above typo.
> d->ident_names = hashmap__new(str_hash_fn, str_equal_fn, NULL);
> if (IS_ERR(d->ident_names)) {
> err = PTR_ERR(d->ident_names);
> d->ident_names = NULL;
> - btf_dump__free(d);
> - return ERR_PTR(err);
> + goto err;
> + }
> + d->type_states = calloc(1 + btf__get_nr_types(d->btf),
> + sizeof(d->type_states[0]));
> + if (!d->type_states) {
> + err = -ENOMEM;
> + goto err;
> + }
> + d->cached_names = calloc(1 + btf__get_nr_types(d->btf),
> + sizeof(d->cached_names[0]));
> + if (!d->cached_names) {
> + err = -ENOMEM;
> + goto err;
> }
>
> + /* VOID is special */
> + d->type_states[0].order_state = ORDERED;
> + d->type_states[0].emit_state = EMITTED;
Not following the logic with 1 + btf__get_nr_types(d->btf) and
above init...
type_states[0] is void. true.
But btf__get_nr_types() includes that type_id=0 == void.
So what this 1+ is for?
I know it's just a move of old code. I just noticed.
Would be great to add a comment.
