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tools/resolve_btfids: Support BTF sorting feature

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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.

Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260109130003.3313716-4-dolinux.peng@gmail.com
This commit is contained in:
Donglin Peng 2026-01-09 20:59:55 +08:00 • committed by Andrii Nakryiko
parent a3acd7d434
commit 230e7d7de5
1 changed files with 64 additions and 0 deletions
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64
tools/bpf/resolve_btfids/main.c
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@ -850,6 +850,67 @@ 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 = 0, start_offs = 1, id;
if (btf__base_btf(btf)) {
start_id = btf__type_cnt(btf__base_btf(btf));
start_offs = 0;
}
nr_types = btf__type_cnt(btf) - start_id;
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 + start_offs, nr_types - start_offs,
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 inline int make_out_path(char *buf, u32 buf_sz, const char *in_path, const char *suffix)
{
int len = snprintf(buf, buf_sz, "%s%s", in_path, suffix);
@ -1025,6 +1086,9 @@ int main(int argc, const char **argv)
if (load_btf(&obj))
goto out;
if (sort_btf_by_name(obj.btf))
goto out;
if (elf_collect(&obj))
goto out;