diff options
| -rw-r--r-- | tools/lib/bpf/btf.c | 137 |
1 files changed, 89 insertions, 48 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index b7513d4cce55..f18d7e6a453c 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -4356,59 +4356,109 @@ static inline __u16 btf_fwd_kind(struct btf_type *t) return btf_kflag(t) ? BTF_KIND_UNION : BTF_KIND_STRUCT; } -/* Check if given two types are identical ARRAY definitions */ -static bool btf_dedup_identical_arrays(struct btf_dedup *d, __u32 id1, __u32 id2) +static bool btf_dedup_identical_types(struct btf_dedup *d, __u32 id1, __u32 id2, int depth) { struct btf_type *t1, *t2; + int k1, k2; +recur: + if (depth <= 0) + return false; t1 = btf_type_by_id(d->btf, id1); t2 = btf_type_by_id(d->btf, id2); - if (!btf_is_array(t1) || !btf_is_array(t2)) + + k1 = btf_kind(t1); + k2 = btf_kind(t2); + if (k1 != k2) return false; - return btf_equal_array(t1, t2); -} + switch (k1) { + case BTF_KIND_UNKN: /* VOID */ + return true; + case BTF_KIND_INT: + return btf_equal_int_tag(t1, t2); + case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: + return btf_compat_enum(t1, t2); + case BTF_KIND_FWD: + case BTF_KIND_FLOAT: + return btf_equal_common(t1, t2); + 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: + if (t1->info != t2->info || t1->name_off != t2->name_off) + return false; + id1 = t1->type; + id2 = t2->type; + goto recur; + case BTF_KIND_ARRAY: { + struct btf_array *a1, *a2; -/* Check if given two types are identical STRUCT/UNION definitions */ -static bool btf_dedup_identical_structs(struct btf_dedup *d, __u32 id1, __u32 id2) -{ - const struct btf_member *m1, *m2; - struct btf_type *t1, *t2; - int n, i; + if (!btf_compat_array(t1, t2)) + return false; - t1 = btf_type_by_id(d->btf, id1); - t2 = btf_type_by_id(d->btf, id2); + a1 = btf_array(t1); + a2 = btf_array(t1); - if (!btf_is_composite(t1) || btf_kind(t1) != btf_kind(t2)) - return false; + if (a1->index_type != a2->index_type && + !btf_dedup_identical_types(d, a1->index_type, a2->index_type, depth - 1)) + return false; - if (!btf_shallow_equal_struct(t1, t2)) - return false; + if (a1->type != a2->type && + !btf_dedup_identical_types(d, a1->type, a2->type, depth - 1)) + return false; - m1 = btf_members(t1); - m2 = btf_members(t2); - for (i = 0, n = btf_vlen(t1); i < n; i++, m1++, m2++) { - if (m1->type != m2->type && - !btf_dedup_identical_arrays(d, m1->type, m2->type) && - !btf_dedup_identical_structs(d, m1->type, m2->type)) + return true; + } + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: { + const struct btf_member *m1, *m2; + int i, n; + + if (!btf_shallow_equal_struct(t1, t2)) return false; + + m1 = btf_members(t1); + m2 = btf_members(t2); + for (i = 0, n = btf_vlen(t1); i < n; i++, m1++, m2++) { + if (m1->type == m2->type) + continue; + if (!btf_dedup_identical_types(d, m1->type, m2->type, depth - 1)) + return false; + } + return true; } - return true; -} + case BTF_KIND_FUNC_PROTO: { + const struct btf_param *p1, *p2; + int i, n; -static bool btf_dedup_identical_ptrs(struct btf_dedup *d, __u32 id1, __u32 id2) -{ - struct btf_type *t1, *t2; + if (!btf_compat_fnproto(t1, t2)) + return false; - t1 = btf_type_by_id(d->btf, id1); - t2 = btf_type_by_id(d->btf, id2); + if (t1->type != t2->type && + !btf_dedup_identical_types(d, t1->type, t2->type, depth - 1)) + return false; - if (!btf_is_ptr(t1) || !btf_is_ptr(t2)) + p1 = btf_params(t1); + p2 = btf_params(t2); + for (i = 0, n = btf_vlen(t1); i < n; i++, p1++, p2++) { + if (p1->type == p2->type) + continue; + if (!btf_dedup_identical_types(d, p1->type, p2->type, depth - 1)) + return false; + } + return true; + } + default: return false; - - return t1->type == t2->type; + } } + /* * Check equivalence of BTF type graph formed by candidate struct/union (we'll * call it "candidate graph" in this description for brevity) to a type graph @@ -4527,22 +4577,13 @@ static int btf_dedup_is_equiv(struct btf_dedup *d, __u32 cand_id, * different fields within the *same* struct. This breaks type * equivalence check, which makes an assumption that candidate * types sub-graph has a consistent and deduped-by-compiler - * types within a single CU. So work around that by explicitly - * allowing identical array types here. + * types within a single CU. And similar situation can happen + * with struct/union sometimes, and event with pointers. + * So accommodate cases like this doing a structural + * comparison recursively, but avoiding being stuck in endless + * loops by limiting the depth up to which we check. */ - if (btf_dedup_identical_arrays(d, hypot_type_id, cand_id)) - return 1; - /* It turns out that similar situation can happen with - * struct/union sometimes, sigh... Handle the case where - * structs/unions are exactly the same, down to the referenced - * type IDs. Anything more complicated (e.g., if referenced - * types are different, but equivalent) is *way more* - * complicated and requires a many-to-many equivalence mapping. - */ - if (btf_dedup_identical_structs(d, hypot_type_id, cand_id)) - return 1; - /* A similar case is again observed for PTRs. */ - if (btf_dedup_identical_ptrs(d, hypot_type_id, cand_id)) + if (btf_dedup_identical_types(d, hypot_type_id, cand_id, 16)) return 1; return 0; } |