selftests/bpf: Ensure typedef are deduplicated in split BTF

If a typedef is defined both in a base and in a split BTF, after
deduplication a single instance should be found in the base BTF.

Suggested-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260417083319.32716-2-atenart@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 6bc31236805cefb6920ea00a093e15209fbe315c..9d61611515938a94c18f472525855a777906cef0 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c
@@ -20,18 +20,22 @@ static void test_split_simple() {
        btf__add_struct(btf1, "s1", 4);                 /* [3] struct s1 { */
        btf__add_field(btf1, "f1", 1, 0, 0);            /*      int f1; */
                                                        /* } */
+       btf__add_typedef(btf1, "t1", 1);                /* [4] typedef int */
 
        VALIDATE_RAW_BTF(
                btf1,
                "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
                "[2] PTR '(anon)' type_id=1",
                "[3] STRUCT 's1' size=4 vlen=1\n"
-               "\t'f1' type_id=1 bits_offset=0");
+               "\t'f1' type_id=1 bits_offset=0",
+               "[4] TYPEDEF 't1' type_id=1");
 
        ASSERT_STREQ(btf_type_c_dump(btf1), "\
 struct s1 {\n\
        int f1;\n\
-};\n\n", "c_dump");
+};\n\
+\n\
+typedef int t1;\n\n", "c_dump");
 
        btf2 = btf__new_empty_split(btf1);
        if (!ASSERT_OK_PTR(btf2, "empty_split_btf"))
@@ -49,39 +53,46 @@ struct s1 {\n\
        ASSERT_EQ(btf_is_int(t), true, "int_kind");
        ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "int", "int_name");
 
-       btf__add_struct(btf2, "s2", 16);                /* [4] struct s2 {      */
-       btf__add_field(btf2, "f1", 6, 0, 0);            /*      struct s1 f1;   */
-       btf__add_field(btf2, "f2", 5, 32, 0);           /*      int f2;         */
+       btf__add_struct(btf2, "s2", 16);                /* [5] struct s2 {      */
+       btf__add_field(btf2, "f1", 7, 0, 0);            /*      struct s1 f1;   */
+       btf__add_field(btf2, "f2", 6, 32, 0);           /*      int f2;         */
        btf__add_field(btf2, "f3", 2, 64, 0);           /*      int *f3;        */
                                                        /* } */
 
        /* duplicated int */
-       btf__add_int(btf2, "int", 4, BTF_INT_SIGNED);   /* [5] int */
+       btf__add_int(btf2, "int", 4, BTF_INT_SIGNED);   /* [6] int */
 
        /* duplicated struct s1 */
-       btf__add_struct(btf2, "s1", 4);                 /* [6] struct s1 { */
-       btf__add_field(btf2, "f1", 5, 0, 0);            /*      int f1; */
+       btf__add_struct(btf2, "s1", 4);                 /* [7] struct s1 { */
+       btf__add_field(btf2, "f1", 6, 0, 0);            /*      int f1; */
                                                        /* } */
 
+       /* duplicated typedef t1 */
+       btf__add_typedef(btf2, "t1", 6);                /* [8] typedef int */
+
        VALIDATE_RAW_BTF(
                btf2,
                "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
                "[2] PTR '(anon)' type_id=1",
                "[3] STRUCT 's1' size=4 vlen=1\n"
                "\t'f1' type_id=1 bits_offset=0",
-               "[4] STRUCT 's2' size=16 vlen=3\n"
-               "\t'f1' type_id=6 bits_offset=0\n"
-               "\t'f2' type_id=5 bits_offset=32\n"
+               "[4] TYPEDEF 't1' type_id=1",
+               "[5] STRUCT 's2' size=16 vlen=3\n"
+               "\t'f1' type_id=7 bits_offset=0\n"
+               "\t'f2' type_id=6 bits_offset=32\n"
                "\t'f3' type_id=2 bits_offset=64",
-               "[5] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
-               "[6] STRUCT 's1' size=4 vlen=1\n"
-               "\t'f1' type_id=5 bits_offset=0");
+               "[6] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
+               "[7] STRUCT 's1' size=4 vlen=1\n"
+               "\t'f1' type_id=6 bits_offset=0",
+               "[8] TYPEDEF 't1' type_id=6");
 
        ASSERT_STREQ(btf_type_c_dump(btf2), "\
 struct s1 {\n\
        int f1;\n\
 };\n\
 \n\
+typedef int t1;\n\
+\n\
 struct s1___2 {\n\
        int f1;\n\
 };\n\
@@ -90,7 +101,9 @@ struct s2 {\n\
        struct s1___2 f1;\n\
        int f2;\n\
        int *f3;\n\
-};\n\n", "c_dump");
+};\n\
+\n\
+typedef int t1___2;\n\n", "c_dump");
 
        err = btf__dedup(btf2, NULL);
        if (!ASSERT_OK(err, "btf_dedup"))
@@ -102,7 +115,8 @@ struct s2 {\n\
                "[2] PTR '(anon)' type_id=1",
                "[3] STRUCT 's1' size=4 vlen=1\n"
                "\t'f1' type_id=1 bits_offset=0",
-               "[4] STRUCT 's2' size=16 vlen=3\n"
+               "[4] TYPEDEF 't1' type_id=1",
+               "[5] STRUCT 's2' size=16 vlen=3\n"
                "\t'f1' type_id=3 bits_offset=0\n"
                "\t'f2' type_id=1 bits_offset=32\n"
                "\t'f3' type_id=2 bits_offset=64");
@@ -112,6 +126,8 @@ struct s1 {\n\
        int f1;\n\
 };\n\
 \n\
+typedef int t1;\n\
+\n\
 struct s2 {\n\
        struct s1 f1;\n\
        int f2;\n\