Commit 9a49afe6 authored by Jiri Olsa's avatar Jiri Olsa Committed by Daniel Borkmann
Browse files

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: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211117194114.347675-2-andrii@kernel.org
parent efdd3eb8

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

+113 −0
Original line number Diff line number Diff line
@@ -314,6 +314,117 @@ static void test_split_struct_duped() { 
	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();

}