selftests/bpf: Add test checking more characteristics

This change adds another type-based self-test that specifically aims to
test some more characteristics of the TYPE_MATCH logic. Specifically, it
covers a few more potential differences between types, such as different
orders, enum variant values, and integer signedness.

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

···
 	TYPE_BASED_CASE(type_based___all_missing, {
 		/* all zeros */
 	}),
+	TYPE_BASED_CASE(type_based___diff, {
+		.struct_exists = 1,
+		.union_exists = 1,
+		.enum_exists = 1,
+		.typedef_named_struct_exists = 1,
+		.typedef_anon_struct_exists = 1,
+		.typedef_struct_ptr_exists = 1,
+		.typedef_int_exists = 1,
+		.typedef_enum_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 = 0,
+		.typedef_enum_matches = 1,
+		.typedef_void_ptr_matches = 1,
+		.typedef_func_proto_matches = 0,
+		.typedef_arr_matches = 0,
+
+		.struct_sz = sizeof(struct a_struct___diff),
+		.union_sz = sizeof(union a_union___diff),
+		.enum_sz = sizeof(enum an_enum___diff),
+		.typedef_named_struct_sz = sizeof(named_struct_typedef___diff),
+		.typedef_anon_struct_sz = sizeof(anon_struct_typedef___diff),
+		.typedef_struct_ptr_sz = sizeof(struct_ptr_typedef___diff),
+		.typedef_int_sz = sizeof(int_typedef___diff),
+		.typedef_enum_sz = sizeof(enum_typedef___diff),
+		.typedef_void_ptr_sz = sizeof(void_ptr_typedef___diff),
+		.typedef_func_proto_sz = sizeof(func_proto_typedef___diff),
+		.typedef_arr_sz = sizeof(arr_typedef___diff),
+	}),
 	TYPE_BASED_CASE(type_based___diff_sz, {
 		.struct_exists = 1,
 		.union_exists = 1,

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

···
+#include "core_reloc_types.h"
+
+void f(struct core_reloc_type_based___diff x) {}

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

···
 struct core_reloc_type_based___all_missing {
 };
 
+/* different member orders, enum variant values, signedness, etc */
+struct a_struct___diff {
+	int x;
+	int a;
+};
+
+union a_union___diff {
+	int z;
+	int y;
+};
+
+typedef struct a_struct___diff named_struct_typedef___diff;
+
+typedef struct { int z, x, y; } anon_struct_typedef___diff;
+
+typedef struct {
+	int c;
+	int b;
+	int a;
+} *struct_ptr_typedef___diff;
+
+enum an_enum___diff {
+	AN_ENUM_VAL2___diff = 0,
+	AN_ENUM_VAL1___diff = 42,
+	AN_ENUM_VAL3___diff = 1,
+};
+
+typedef unsigned int int_typedef___diff;
+
+typedef enum { TYPEDEF_ENUM_VAL2___diff, TYPEDEF_ENUM_VAL1___diff = 50 } enum_typedef___diff;
+
+typedef const void *void_ptr_typedef___diff;
+
+typedef int_typedef___diff (*func_proto_typedef___diff)(long);
+
+typedef char arr_typedef___diff[3];
+
+struct core_reloc_type_based___diff {
+	struct a_struct___diff f1;
+	union a_union___diff f2;
+	enum an_enum___diff f3;
+	named_struct_typedef___diff f4;
+	anon_struct_typedef___diff f5;
+	struct_ptr_typedef___diff f6;
+	int_typedef___diff f7;
+	enum_typedef___diff f8;
+	void_ptr_typedef___diff f9;
+	func_proto_typedef___diff f10;
+	arr_typedef___diff f11;
+};
+
 /* different type sizes, extra modifiers, anon vs named enums, etc */
 struct a_struct___diff_sz {
 	long x;