On Wed, Jan 12, 2022 at 12:16 PM Yonghong Song <yhs@xxxxxx> wrote:
> +
> + /* check __user tag */
> + t = btf_type_by_id(btf, mtype->type);
> + if (btf_type_is_type_tag(t)) {
> + tag_value = __btf_name_by_offset(btf, t->name_off);
> + if (strcmp(tag_value, "user") == 0)
> + tmp_flag = MEM_USER;
> + }
> +
> stype = btf_type_skip_modifiers(btf, mtype->type, &id);
Does LLVM guarantee that btf_tag will be the first in the modifiers?
Looking at the selftest:
+struct bpf_testmod_btf_type_tag_2 {
+ struct bpf_testmod_btf_type_tag_1 __user *p;
+};
What if there are 'const' or 'volatile' modifiers on that pointer too?
And in different order with btf_tag?
BTF gets normalized or not?
I wonder whether we should introduce something like
btf_type_collect_modifiers() instead of btf_type_skip_modifiers() ?
