selftests/bpf: Add btf_dedup case with duplicated structs within CU

Add an artificial minimal example simulating compilers producing two
different types within a single CU that correspond to identical struct
definitions.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211117194114.347675-2-andrii@kernel.org

diff --git a/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c b/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c
index 9d3b8d7..94ff975 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c
@@ -314,6 +314,117 @@ cleanup:
        btf__free(btf1);
 }
 
+static void btf_add_dup_struct_in_cu(struct btf *btf, int start_id)
+{
+#define ID(n) (start_id + n)
+       btf__set_pointer_size(btf, 8); /* enforce 64-bit arch */
+
+       btf__add_int(btf, "int", 4, BTF_INT_SIGNED);    /* [1] int */
+
+       btf__add_struct(btf, "s", 8);                   /* [2] struct s { */
+       btf__add_field(btf, "a", ID(3), 0, 0);          /*      struct anon a; */
+       btf__add_field(btf, "b", ID(4), 0, 0);          /*      struct anon b; */
+                                                       /* } */
+
+       btf__add_struct(btf, "(anon)", 8);              /* [3] struct anon { */
+       btf__add_field(btf, "f1", ID(1), 0, 0);         /*      int f1; */
+       btf__add_field(btf, "f2", ID(1), 32, 0);        /*      int f2; */
+                                                       /* } */
+
+       btf__add_struct(btf, "(anon)", 8);              /* [4] struct anon { */
+       btf__add_field(btf, "f1", ID(1), 0, 0);         /*      int f1; */
+       btf__add_field(btf, "f2", ID(1), 32, 0);        /*      int f2; */
+                                                       /* } */
+#undef ID
+}
+
+static void test_split_dup_struct_in_cu()
+{
+       struct btf *btf1, *btf2;
+       int err;
+
+       /* generate the base data.. */
+       btf1 = btf__new_empty();
+       if (!ASSERT_OK_PTR(btf1, "empty_main_btf"))
+               return;
+
+       btf_add_dup_struct_in_cu(btf1, 0);
+
+       VALIDATE_RAW_BTF(
+                       btf1,
+                       "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
+                       "[2] STRUCT 's' size=8 vlen=2\n"
+                       "\t'a' type_id=3 bits_offset=0\n"
+                       "\t'b' type_id=4 bits_offset=0",
+                       "[3] STRUCT '(anon)' size=8 vlen=2\n"
+                       "\t'f1' type_id=1 bits_offset=0\n"
+                       "\t'f2' type_id=1 bits_offset=32",
+                       "[4] STRUCT '(anon)' size=8 vlen=2\n"
+                       "\t'f1' type_id=1 bits_offset=0\n"
+                       "\t'f2' type_id=1 bits_offset=32");
+
+       /* ..dedup them... */
+       err = btf__dedup(btf1, NULL, NULL);
+       if (!ASSERT_OK(err, "btf_dedup"))
+               goto cleanup;
+
+       VALIDATE_RAW_BTF(
+                       btf1,
+                       "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
+                       "[2] STRUCT 's' size=8 vlen=2\n"
+                       "\t'a' type_id=3 bits_offset=0\n"
+                       "\t'b' type_id=3 bits_offset=0",
+                       "[3] STRUCT '(anon)' size=8 vlen=2\n"
+                       "\t'f1' type_id=1 bits_offset=0\n"
+                       "\t'f2' type_id=1 bits_offset=32");
+
+       /* and add the same data on top of it */
+       btf2 = btf__new_empty_split(btf1);
+       if (!ASSERT_OK_PTR(btf2, "empty_split_btf"))
+               goto cleanup;
+
+       btf_add_dup_struct_in_cu(btf2, 3);
+
+       VALIDATE_RAW_BTF(
+                       btf2,
+                       "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
+                       "[2] STRUCT 's' size=8 vlen=2\n"
+                       "\t'a' type_id=3 bits_offset=0\n"
+                       "\t'b' type_id=3 bits_offset=0",
+                       "[3] STRUCT '(anon)' size=8 vlen=2\n"
+                       "\t'f1' type_id=1 bits_offset=0\n"
+                       "\t'f2' type_id=1 bits_offset=32",
+                       "[4] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
+                       "[5] STRUCT 's' size=8 vlen=2\n"
+                       "\t'a' type_id=6 bits_offset=0\n"
+                       "\t'b' type_id=7 bits_offset=0",
+                       "[6] STRUCT '(anon)' size=8 vlen=2\n"
+                       "\t'f1' type_id=4 bits_offset=0\n"
+                       "\t'f2' type_id=4 bits_offset=32",
+                       "[7] STRUCT '(anon)' size=8 vlen=2\n"
+                       "\t'f1' type_id=4 bits_offset=0\n"
+                       "\t'f2' type_id=4 bits_offset=32");
+
+       err = btf__dedup(btf2, NULL, NULL);
+       if (!ASSERT_OK(err, "btf_dedup"))
+               goto cleanup;
+
+       /* after dedup it should match the original data */
+       VALIDATE_RAW_BTF(
+                       btf2,
+                       "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
+                       "[2] STRUCT 's' size=8 vlen=2\n"
+                       "\t'a' type_id=3 bits_offset=0\n"
+                       "\t'b' type_id=3 bits_offset=0",
+                       "[3] STRUCT '(anon)' size=8 vlen=2\n"
+                       "\t'f1' type_id=1 bits_offset=0\n"
+                       "\t'f2' type_id=1 bits_offset=32");
+
+cleanup:
+       btf__free(btf2);
+       btf__free(btf1);
+}
+
 void test_btf_dedup_split()
 {
        if (test__start_subtest("split_simple"))
@@ -322,4 +433,6 @@ void test_btf_dedup_split()
                test_split_struct_duped();
        if (test__start_subtest("split_fwd_resolve"))
                test_split_fwd_resolve();
+       if (test__start_subtest("split_dup_struct_in_cu"))
+               test_split_dup_struct_in_cu();
 }