resolve_btfids: Refactor the sort_btf_by_name function

Preserve original relative order of anonymous or same-named
types to improve the consistency.

No functional changes.

Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260202120114.3707141-1-dolinux.peng@gmail.com

diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index db8d1554bdcca216b8c7e26406927f035aa21d3c..ca7fcd03efb6ea31b3b3b6ef1a960ac957f1cac4 100644 (file)
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c
@@ -1226,22 +1226,26 @@ static int cmp_type_names(const void *a, const void *b, void *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;
+       int r;
 
        na = btf__str_by_offset(btf, ta->name_off);
        nb = btf__str_by_offset(btf, tb->name_off);
-       return strcmp(na, nb);
+       r = strcmp(na, nb);
+       if (r != 0)
+               return r;
+
+       /* preserve original relative order of anonymous or same-named types */
+       return *(__u32 *)a < *(__u32 *)b ? -1 : 1;
 }
 
 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;
+       __u32 start_id = 0, id;
 
-       if (btf__base_btf(btf)) {
+       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));
@@ -1259,8 +1263,8 @@ static int sort_btf_by_name(struct btf *btf)
        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);
+       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;