Merge branch 'fix-fwd-enum-resolution'
Andrii Nakryiko says:
====================
This patchset adds ability to resolve forward-declared enums into their
corresponding full enum definition types during type deduplication,
eliminating one of the reasons for having duplicated graphs of types.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 1b8d8cd..87e3020 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -1602,16 +1602,12 @@ static bool btf_equal_int(struct btf_type *t1, struct btf_type *t2)
/* Calculate type signature hash of ENUM. */
static __u32 btf_hash_enum(struct btf_type *t)
{
- struct btf_enum *member = (struct btf_enum *)(t + 1);
- __u32 vlen = BTF_INFO_VLEN(t->info);
- __u32 h = btf_hash_common(t);
- int i;
+ __u32 h;
- for (i = 0; i < vlen; i++) {
- h = hash_combine(h, member->name_off);
- h = hash_combine(h, member->val);
- member++;
- }
+ /* don't hash vlen and enum members to support enum fwd resolving */
+ h = hash_combine(0, t->name_off);
+ h = hash_combine(h, t->info & ~0xffff);
+ h = hash_combine(h, t->size);
return h;
}
@@ -1637,6 +1633,22 @@ static bool btf_equal_enum(struct btf_type *t1, struct btf_type *t2)
return true;
}
+static inline bool btf_is_enum_fwd(struct btf_type *t)
+{
+ return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM &&
+ BTF_INFO_VLEN(t->info) == 0;
+}
+
+static bool btf_compat_enum(struct btf_type *t1, struct btf_type *t2)
+{
+ if (!btf_is_enum_fwd(t1) && !btf_is_enum_fwd(t2))
+ return btf_equal_enum(t1, t2);
+ /* ignore vlen when comparing */
+ return t1->name_off == t2->name_off &&
+ (t1->info & ~0xffff) == (t2->info & ~0xffff) &&
+ t1->size == t2->size;
+}
+
/*
* Calculate type signature hash of STRUCT/UNION, ignoring referenced type IDs,
* as referenced type IDs equivalence is established separately during type
@@ -1860,6 +1872,17 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id)
new_id = cand_node->type_id;
break;
}
+ if (d->opts.dont_resolve_fwds)
+ continue;
+ if (btf_compat_enum(t, cand)) {
+ if (btf_is_enum_fwd(t)) {
+ /* resolve fwd to full enum */
+ new_id = cand_node->type_id;
+ break;
+ }
+ /* resolve canonical enum fwd to full enum */
+ d->map[cand_node->type_id] = type_id;
+ }
}
break;
@@ -2084,15 +2107,15 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id,
return fwd_kind == real_kind;
}
- if (cand_type->info != canon_type->info)
- return 0;
-
switch (cand_kind) {
case BTF_KIND_INT:
return btf_equal_int(cand_type, canon_type);
case BTF_KIND_ENUM:
- return btf_equal_enum(cand_type, canon_type);
+ if (d->opts.dont_resolve_fwds)
+ return btf_equal_enum(cand_type, canon_type);
+ else
+ return btf_compat_enum(cand_type, canon_type);
case BTF_KIND_FWD:
return btf_equal_common(cand_type, canon_type);
@@ -2103,6 +2126,8 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id,
case BTF_KIND_PTR:
case BTF_KIND_TYPEDEF:
case BTF_KIND_FUNC:
+ if (cand_type->info != canon_type->info)
+ return 0;
return btf_dedup_is_equiv(d, cand_type->type, canon_type->type);
case BTF_KIND_ARRAY: {
diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c
index 38797aa..23e3b31 100644
--- a/tools/testing/selftests/bpf/test_btf.c
+++ b/tools/testing/selftests/bpf/test_btf.c
@@ -5874,6 +5874,50 @@ const struct btf_dedup_test dedup_tests[] = {
.dont_resolve_fwds = false,
},
},
+{
+ .descr = "dedup: enum fwd resolution",
+ .input = {
+ .raw_types = {
+ /* [1] fwd enum 'e1' before full enum */
+ BTF_TYPE_ENC(NAME_NTH(1), BTF_INFO_ENC(BTF_KIND_ENUM, 0, 0), 4),
+ /* [2] full enum 'e1' after fwd */
+ BTF_TYPE_ENC(NAME_NTH(1), BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1), 4),
+ BTF_ENUM_ENC(NAME_NTH(2), 123),
+ /* [3] full enum 'e2' before fwd */
+ BTF_TYPE_ENC(NAME_NTH(3), BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1), 4),
+ BTF_ENUM_ENC(NAME_NTH(4), 456),
+ /* [4] fwd enum 'e2' after full enum */
+ BTF_TYPE_ENC(NAME_NTH(3), BTF_INFO_ENC(BTF_KIND_ENUM, 0, 0), 4),
+ /* [5] incompatible fwd enum with different size */
+ BTF_TYPE_ENC(NAME_NTH(1), BTF_INFO_ENC(BTF_KIND_ENUM, 0, 0), 1),
+ /* [6] incompatible full enum with different value */
+ BTF_TYPE_ENC(NAME_NTH(1), BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1), 4),
+ BTF_ENUM_ENC(NAME_NTH(2), 321),
+ BTF_END_RAW,
+ },
+ BTF_STR_SEC("\0e1\0e1_val\0e2\0e2_val"),
+ },
+ .expect = {
+ .raw_types = {
+ /* [1] full enum 'e1' */
+ BTF_TYPE_ENC(NAME_NTH(1), BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1), 4),
+ BTF_ENUM_ENC(NAME_NTH(2), 123),
+ /* [2] full enum 'e2' */
+ BTF_TYPE_ENC(NAME_NTH(3), BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1), 4),
+ BTF_ENUM_ENC(NAME_NTH(4), 456),
+ /* [3] incompatible fwd enum with different size */
+ BTF_TYPE_ENC(NAME_NTH(1), BTF_INFO_ENC(BTF_KIND_ENUM, 0, 0), 1),
+ /* [4] incompatible full enum with different value */
+ BTF_TYPE_ENC(NAME_NTH(1), BTF_INFO_ENC(BTF_KIND_ENUM, 0, 1), 4),
+ BTF_ENUM_ENC(NAME_NTH(2), 321),
+ BTF_END_RAW,
+ },
+ BTF_STR_SEC("\0e1\0e1_val\0e2\0e2_val"),
+ },
+ .opts = {
+ .dont_resolve_fwds = false,
+ },
+},
};