static int btf_dedup_ref_type()

in third/libbpf/src/btf.c [4335:4459]

• 107 lines of code
• 26 McCabe index (conditional complexity)

static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id)
{
	struct hashmap_entry *hash_entry;
	__u32 new_id = type_id, cand_id;
	struct btf_type *t, *cand;
	/* if we don't find equivalent type, then we are representative type */
	int ref_type_id;
	long h;

	if (d->map[type_id] == BTF_IN_PROGRESS_ID)
		return -ELOOP;
	if (d->map[type_id] <= BTF_MAX_NR_TYPES)
		return resolve_type_id(d, type_id);

	t = btf_type_by_id(d->btf, type_id);
	d->map[type_id] = BTF_IN_PROGRESS_ID;

	switch (btf_kind(t)) {
	case BTF_KIND_CONST:
	case BTF_KIND_VOLATILE:
	case BTF_KIND_RESTRICT:
	case BTF_KIND_PTR:
	case BTF_KIND_TYPEDEF:
	case BTF_KIND_FUNC:
	case BTF_KIND_TYPE_TAG:
		ref_type_id = btf_dedup_ref_type(d, t->type);
		if (ref_type_id < 0)
			return ref_type_id;
		t->type = ref_type_id;

		h = btf_hash_common(t);
		for_each_dedup_cand(d, hash_entry, h) {
			cand_id = (__u32)(long)hash_entry->value;
			cand = btf_type_by_id(d->btf, cand_id);
			if (btf_equal_common(t, cand)) {
				new_id = cand_id;
				break;
			}
		}
		break;

	case BTF_KIND_DECL_TAG:
		ref_type_id = btf_dedup_ref_type(d, t->type);
		if (ref_type_id < 0)
			return ref_type_id;
		t->type = ref_type_id;

		h = btf_hash_int_decl_tag(t);
		for_each_dedup_cand(d, hash_entry, h) {
			cand_id = (__u32)(long)hash_entry->value;
			cand = btf_type_by_id(d->btf, cand_id);
			if (btf_equal_int_tag(t, cand)) {
				new_id = cand_id;
				break;
			}
		}
		break;

	case BTF_KIND_ARRAY: {
		struct btf_array *info = btf_array(t);

		ref_type_id = btf_dedup_ref_type(d, info->type);
		if (ref_type_id < 0)
			return ref_type_id;
		info->type = ref_type_id;

		ref_type_id = btf_dedup_ref_type(d, info->index_type);
		if (ref_type_id < 0)
			return ref_type_id;
		info->index_type = ref_type_id;

		h = btf_hash_array(t);
		for_each_dedup_cand(d, hash_entry, h) {
			cand_id = (__u32)(long)hash_entry->value;
			cand = btf_type_by_id(d->btf, cand_id);
			if (btf_equal_array(t, cand)) {
				new_id = cand_id;
				break;
			}
		}
		break;
	}

	case BTF_KIND_FUNC_PROTO: {
		struct btf_param *param;
		__u16 vlen;
		int i;

		ref_type_id = btf_dedup_ref_type(d, t->type);
		if (ref_type_id < 0)
			return ref_type_id;
		t->type = ref_type_id;

		vlen = btf_vlen(t);
		param = btf_params(t);
		for (i = 0; i < vlen; i++) {
			ref_type_id = btf_dedup_ref_type(d, param->type);
			if (ref_type_id < 0)
				return ref_type_id;
			param->type = ref_type_id;
			param++;
		}

		h = btf_hash_fnproto(t);
		for_each_dedup_cand(d, hash_entry, h) {
			cand_id = (__u32)(long)hash_entry->value;
			cand = btf_type_by_id(d->btf, cand_id);
			if (btf_equal_fnproto(t, cand)) {
				new_id = cand_id;
				break;
			}
		}
		break;
	}

	default:
		return -EINVAL;
	}

	d->map[type_id] = new_id;
	if (type_id == new_id && btf_dedup_table_add(d, h, type_id))
		return -ENOMEM;

	return new_id;
}