selftests/bpf: Update btf_dump case for conflicting names

Update btf_dump case for conflicting names caused by forward declaration.
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220301053250.1464204-3-xukuohai@huawei.com

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

@@ -148,22 +148,38 @@ static void test_btf_dump_incremental(void)
 
 	/* First, generate BTF corresponding to the following C code:
 	 *
-	 * enum { VAL = 1 };
+	 * enum x;
+	 *
+	 * enum x { X = 1 };
+	 *
+	 * enum { Y = 1 };
+	 *
+	 * struct s;
 	 *
 	 * struct s { int x; };
 	 *
 	 */
+	id = btf__add_enum(btf, "x", 4);
+	ASSERT_EQ(id, 1, "enum_declaration_id");
+	id = btf__add_enum(btf, "x", 4);
+	ASSERT_EQ(id, 2, "named_enum_id");
+	err = btf__add_enum_value(btf, "X", 1);
+	ASSERT_OK(err, "named_enum_val_ok");
+
 	id = btf__add_enum(btf, NULL, 4);
-	ASSERT_EQ(id, 1, "enum_id");
-	err = btf__add_enum_value(btf, "VAL", 1);
-	ASSERT_OK(err, "enum_val_ok");
+	ASSERT_EQ(id, 3, "anon_enum_id");
+	err = btf__add_enum_value(btf, "Y", 1);
+	ASSERT_OK(err, "anon_enum_val_ok");
 
 	id = btf__add_int(btf, "int", 4, BTF_INT_SIGNED);
-	ASSERT_EQ(id, 2, "int_id");
+	ASSERT_EQ(id, 4, "int_id");
+
+	id = btf__add_fwd(btf, "s", BTF_FWD_STRUCT);
+	ASSERT_EQ(id, 5, "fwd_id");
 
 	id = btf__add_struct(btf, "s", 4);
-	ASSERT_EQ(id, 3, "struct_id");
-	err = btf__add_field(btf, "x", 2, 0, 0);
+	ASSERT_EQ(id, 6, "struct_id");
+	err = btf__add_field(btf, "x", 4, 0, 0);
 	ASSERT_OK(err, "field_ok");
 
 	for (i = 1; i < btf__type_cnt(btf); i++) {
@@ -173,11 +189,20 @@ static void test_btf_dump_incremental(void)
 
 	fflush(dump_buf_file);
 	dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */
+
 	ASSERT_STREQ(dump_buf,
+"enum x;\n"
+"\n"
+"enum x {\n"
+"	X = 1,\n"
+"};\n"
+"\n"
 "enum {\n"
-"	VAL = 1,\n"
+"	Y = 1,\n"
 "};\n"
 "\n"
+"struct s;\n"
+"\n"
 "struct s {\n"
 "	int x;\n"
 "};\n\n", "c_dump1");
@@ -199,10 +224,12 @@ static void test_btf_dump_incremental(void)
 	fseek(dump_buf_file, 0, SEEK_SET);
 
 	id = btf__add_struct(btf, "s", 4);
-	ASSERT_EQ(id, 4, "struct_id");
-	err = btf__add_field(btf, "x", 1, 0, 0);
+	ASSERT_EQ(id, 7, "struct_id");
+	err = btf__add_field(btf, "x", 2, 0, 0);
+	ASSERT_OK(err, "field_ok");
+	err = btf__add_field(btf, "y", 3, 32, 0);
 	ASSERT_OK(err, "field_ok");
-	err = btf__add_field(btf, "s", 3, 32, 0);
+	err = btf__add_field(btf, "s", 6, 64, 0);
 	ASSERT_OK(err, "field_ok");
 
 	for (i = 1; i < btf__type_cnt(btf); i++) {
@@ -214,9 +241,10 @@ static void test_btf_dump_incremental(void)
 	dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */
 	ASSERT_STREQ(dump_buf,
 "struct s___2 {\n"
+"	enum x x;\n"
 "	enum {\n"
-"		VAL___2 = 1,\n"
-"	} x;\n"
+"		Y___2 = 1,\n"
+"	} y;\n"
 "	struct s s;\n"
 "};\n\n" , "c_dump1");