btf__add_decl_tag
err = btf__add_decl_tag(btf, tag_name, new_func_id, idx);
LIBBPF_API int btf__add_decl_tag(struct btf *btf, const char *value, int ref_type_id,
tag_id = btf__add_decl_tag(btf, ctx_tag, func_rec->type_id, arg_idx);
btf__add_decl_tag(btf, "decltag", 11, -1); /* [18] decltag const int; */
id = btf__add_decl_tag(btf, "tag1", 16, -1);
id = btf__add_decl_tag(btf, "tag2", 14, 1);
id = btf__add_decl_tag(btf, "contains:bar:a", foo_btf_id, 0);
id = btf__add_decl_tag(btf, "contains:baz:a", 5, 0);
id = btf__add_decl_tag(btf, "contains:foo:b", 5, 0);
id = btf__add_decl_tag(btf, "contains:bar:bar", 5, 1);
id = btf__add_decl_tag(btf, "contains:foo:c", 5, 1);
id = btf__add_decl_tag(btf, "contains:bar:a", 5, 0);
id = btf__add_decl_tag(btf, "contains:foo:b", 5, 0);
id = btf__add_decl_tag(btf, "contains:foo:b", 5, 0);
id = btf__add_decl_tag(btf, "contains:bar:b", 5, 0);
id = btf__add_decl_tag(btf, "contains:foo:b", 7, 0);
id = btf__add_decl_tag(btf, "contains:bar:a", 5, 0);
id = btf__add_decl_tag(btf, "contains:bar:b", 5, 0);
id = btf__add_decl_tag(btf, "contains:baz:a", 7, 0);
id = btf__add_decl_tag(btf, "contains:bar:b", 5, 0);
id = btf__add_decl_tag(btf, "contains:baz:a", 7, 0);
id = btf__add_decl_tag(btf, "contains:bar:b", 5, 0);
id = btf__add_decl_tag(btf, "contains:baz:b", 7, 0);
id = btf__add_decl_tag(btf, "contains:bam:a", 9, 0);