There are currently no multidimensional array tests for
BTF-based data dumping. In BTF, a multidimensional array is
represented as an array with an element type of array. However,
pahole and llvm collapse multidimensional arrays into a
one-dimensional array [1]. Accordingly, the test uses the BTF
add interfaces to create a multidimensional char [2][4] array,
and tests type-based display matches expectations.
[1] See Documentation/bpf/btf.rst Section 2.2.3
Suggested-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
tools/testing/selftests/bpf/prog_tests/btf_dump.c | 39 +++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/btf_dump.c b/tools/testing/selftests/bpf/prog_tests/btf_dump.c
index 52ccf0c..70d26cf 100644
--- a/tools/testing/selftests/bpf/prog_tests/btf_dump.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf_dump.c
@@ -681,6 +681,45 @@ static void test_btf_dump_struct_data(struct btf *btf, struct btf_dump *d,
"}",
{ .cb = { 0, 0, 1, 0, 0},});
+ /* multidimensional array; because pahole and llvm collapse arrays
+ * with multiple dimensions into a single dimension, we add a
+ * multidimensional array explicitly.
+ */
+ type_id = btf__find_by_name(btf, "char");
+ if (ASSERT_GT(type_id, 0, "find char")) {
+ __s32 index_id, array1_id, array2_id;
+ char strs[2][4] = { "one", "two" };
+
+ index_id = btf__find_by_name(btf, "int");
+ ASSERT_GT(index_id, 0, "find int");
+
+ array2_id = btf__add_array(btf, index_id, type_id, 4);
+ ASSERT_GT(array2_id, 0, "add multidim 2");
+
+ array1_id = btf__add_array(btf, index_id, array2_id, 2);
+ ASSERT_GT(array1_id, 0, "add multidim 1");
+
+ str[0] = '\0';
+ ret = btf_dump__dump_type_data(d, array1_id, &strs, sizeof(strs), &opts);
+ ASSERT_GT(ret, 0, "dump multidimensional array");
+
+ ASSERT_STREQ(str,
+"(char[2][4])[\n"
+" [\n"
+" 'o',\n"
+" 'n',\n"
+" 'e',\n"
+" ],\n"
+" [\n"
+" 't',\n"
+" 'w',\n"
+" 'o',\n"
+" ],\n"
+"]",
+ "multidimensional char array matches");
+ }
+
+
/* struct with bitfields */
TEST_BTF_DUMP_DATA_C(btf, d, "struct", str, struct bpf_insn, BTF_F_COMPACT,
{.code = (__u8)1,.dst_reg = (__u8)0x2,.src_reg = (__u8)0x3,.off = (__s16)4,.imm = (__s32)5,});
--
1.8.3.1
