From: pengdonglin This introduces a new BTF sorting phase that specifically sorts BTF types by name in ascending order, so that the binary search can be used to look up types. Cc: Eduard Zingerman Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Alan Maguire Cc: Ihor Solodrai Cc: Xiaoqin Zhang Signed-off-by: pengdonglin --- tools/bpf/resolve_btfids/main.c | 68 +++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c index e0e792017e77..b4ec3b556518 100644 --- a/tools/bpf/resolve_btfids/main.c +++ b/tools/bpf/resolve_btfids/main.c @@ -846,6 +846,71 @@ static int dump_raw_btf(struct btf *btf, const char *out_path) return 0; } +/* + * Sort types by name in ascending order resulting in all + * anonymous types being placed before named types. + */ +static int cmp_type_names(const void *a, const void *b, void *priv) +{ + struct btf *btf = (struct btf *)priv; + const struct btf_type *ta = btf__type_by_id(btf, *(__u32 *)a); + const struct btf_type *tb = btf__type_by_id(btf, *(__u32 *)b); + const char *na, *nb; + + na = btf__str_by_offset(btf, ta->name_off); + nb = btf__str_by_offset(btf, tb->name_off); + return strcmp(na, nb); +} + +static int sort_btf_by_name(struct btf *btf) +{ + __u32 *permute_ids = NULL, *id_map = NULL; + int nr_types, i, err = 0; + __u32 start_id = 1, id; + + if (btf__base_btf(btf)) + start_id = btf__type_cnt(btf__base_btf(btf)); + nr_types = btf__type_cnt(btf) - start_id; + if (nr_types < 2) + goto out; + + permute_ids = calloc(nr_types, sizeof(*permute_ids)); + if (!permute_ids) { + err = -ENOMEM; + goto out; + } + + id_map = calloc(nr_types, sizeof(*id_map)); + if (!id_map) { + err = -ENOMEM; + goto out; + } + + for (i = 0, id = start_id; i < nr_types; i++, id++) + permute_ids[i] = id; + + qsort_r(permute_ids, nr_types, sizeof(*permute_ids), cmp_type_names, btf); + + for (i = 0; i < nr_types; i++) { + id = permute_ids[i] - start_id; + id_map[id] = i + start_id; + } + + err = btf__permute(btf, id_map, nr_types, NULL); + if (err) + pr_err("FAILED: btf permute: %s\n", strerror(-err)); + +out: + free(permute_ids); + free(id_map); + return err; +} + +static int btf2btf(struct object *obj) +{ + return sort_btf_by_name(obj->btf); +} + static inline int make_out_path(char *buf, const char *in_path, const char *suffix) { int len = snprintf(buf, PATH_MAX, "%s%s", in_path, suffix); @@ -904,6 +969,9 @@ int main(int argc, const char **argv) if (load_btf(&obj)) goto out; + if (btf2btf(&obj)) + goto out; + if (elf_collect(&obj)) goto out; -- 2.34.1