selftests/bpf: Add type-match checks to type-based tests

Now that we have type-match logic in both libbpf and the kernel, this
change adjusts the existing BPF self tests to check this functionality.
Specifically, we extend the existing type-based tests to check the
previously introduced bpf_core_type_matches macro.

Signed-off-by: Daniel Müller <[e-mail]>
Signed-off-by: Andrii Nakryiko <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

tools/testing/selftests/bpf/prog_tests/core_reloc.c

···
 	return 0;
 }
 
-
 static const struct core_reloc_test_case test_cases[] = {
 	/* validate we can find kernel image and use its BTF for relocs */
 	{
···
 	SIZE_CASE(size___diff_offs),
 	SIZE_ERR_CASE(size___err_ambiguous),
 
-	/* validate type existence and size relocations */
+	/* validate type existence, match, and size relocations */
 	TYPE_BASED_CASE(type_based, {
 		.struct_exists = 1,
 		.union_exists = 1,
···
 		.typedef_void_ptr_exists = 1,
 		.typedef_func_proto_exists = 1,
 		.typedef_arr_exists = 1,
+
+		.struct_matches = 1,
+		.union_matches = 1,
+		.enum_matches = 1,
+		.typedef_named_struct_matches = 1,
+		.typedef_anon_struct_matches = 1,
+		.typedef_struct_ptr_matches = 1,
+		.typedef_int_matches = 1,
+		.typedef_enum_matches = 1,
+		.typedef_void_ptr_matches = 1,
+		.typedef_func_proto_matches = 1,
+		.typedef_arr_matches = 1,
+
 		.struct_sz = sizeof(struct a_struct),
 		.union_sz = sizeof(union a_union),
 		.enum_sz = sizeof(enum an_enum),
···
 		.typedef_void_ptr_exists = 1,
 		.typedef_func_proto_exists = 1,
 		.typedef_arr_exists = 1,
+
+		.struct_matches = 0,
+		.union_matches = 0,
+		.enum_matches = 0,
+		.typedef_named_struct_matches = 0,
+		.typedef_anon_struct_matches = 0,
+		.typedef_struct_ptr_matches = 1,
+		.typedef_int_matches = 0,
+		.typedef_enum_matches = 0,
+		.typedef_void_ptr_matches = 1,
+		.typedef_func_proto_matches = 0,
+		.typedef_arr_matches = 0,
+
 		.struct_sz = sizeof(struct a_struct___diff_sz),
 		.union_sz = sizeof(union a_union___diff_sz),
 		.enum_sz = sizeof(enum an_enum___diff_sz),
···
 	}),
 	TYPE_BASED_CASE(type_based___incompat, {
 		.enum_exists = 1,
+		.enum_matches = 1,
 		.enum_sz = sizeof(enum an_enum),
 	}),
 	TYPE_BASED_CASE(type_based___fn_wrong_args, {
 		.struct_exists = 1,
+		.struct_matches = 1,
 		.struct_sz = sizeof(struct a_struct),
 	}),
 

tools/testing/selftests/bpf/progs/core_reloc_types.h

···
 };
 
 /*
- * TYPE EXISTENCE & SIZE
+ * TYPE EXISTENCE, MATCH & SIZE
  */
 struct core_reloc_type_based_output {
 	bool struct_exists;
···
 	bool typedef_void_ptr_exists;
 	bool typedef_func_proto_exists;
 	bool typedef_arr_exists;
+
+	bool struct_matches;
+	bool union_matches;
+	bool enum_matches;
+	bool typedef_named_struct_matches;
+	bool typedef_anon_struct_matches;
+	bool typedef_struct_ptr_matches;
+	bool typedef_int_matches;
+	bool typedef_enum_matches;
+	bool typedef_void_ptr_matches;
+	bool typedef_func_proto_matches;
+	bool typedef_arr_matches;
 
 	int struct_sz;
 	int union_sz;

tools/testing/selftests/bpf/progs/test_core_reloc_type_based.c

···
 	bool typedef_func_proto_exists;
 	bool typedef_arr_exists;
 
+	bool struct_matches;
+	bool union_matches;
+	bool enum_matches;
+	bool typedef_named_struct_matches;
+	bool typedef_anon_struct_matches;
+	bool typedef_struct_ptr_matches;
+	bool typedef_int_matches;
+	bool typedef_enum_matches;
+	bool typedef_void_ptr_matches;
+	bool typedef_func_proto_matches;
+	bool typedef_arr_matches;
+
 	int struct_sz;
 	int union_sz;
 	int enum_sz;
···
 SEC("raw_tracepoint/sys_enter")
 int test_core_type_based(void *ctx)
 {
-#if __has_builtin(__builtin_preserve_type_info)
+	/* Support for the BPF_TYPE_MATCHES argument to the
+	 * __builtin_preserve_type_info builtin was added at some point during
+	 * development of clang 15 and it's what we require for this test. Part of it
+	 * could run with merely __builtin_preserve_type_info (which could be checked
+	 * separately), but we have to find an upper bound.
+	 */
+#if __has_builtin(__builtin_preserve_type_info) && __clang_major__ >= 15
 	struct core_reloc_type_based_output *out = (void *)&data.out;
 
 	out->struct_exists = bpf_core_type_exists(struct a_struct);
···
 	out->typedef_void_ptr_exists = bpf_core_type_exists(void_ptr_typedef);
 	out->typedef_func_proto_exists = bpf_core_type_exists(func_proto_typedef);
 	out->typedef_arr_exists = bpf_core_type_exists(arr_typedef);
+
+	out->struct_matches = bpf_core_type_matches(struct a_struct);
+	out->union_matches = bpf_core_type_matches(union a_union);
+	out->enum_matches = bpf_core_type_matches(enum an_enum);
+	out->typedef_named_struct_matches = bpf_core_type_matches(named_struct_typedef);
+	out->typedef_anon_struct_matches = bpf_core_type_matches(anon_struct_typedef);
+	out->typedef_struct_ptr_matches = bpf_core_type_matches(struct_ptr_typedef);
+	out->typedef_int_matches = bpf_core_type_matches(int_typedef);
+	out->typedef_enum_matches = bpf_core_type_matches(enum_typedef);
+	out->typedef_void_ptr_matches = bpf_core_type_matches(void_ptr_typedef);
+	out->typedef_func_proto_matches = bpf_core_type_matches(func_proto_typedef);
+	out->typedef_arr_matches = bpf_core_type_matches(arr_typedef);
 
 	out->struct_sz = bpf_core_type_size(struct a_struct);
 	out->union_sz = bpf_core_type_size(union a_union);