Re: [PATCH bpf-next] selftests/bpf: move struct definitions out of function params

sdf
2022-12-21T19:07:46Z

On 12/20, James Hilliard wrote:
> Anonymous structs can't be declared inside function parameter
> definitions in current c standards, however clang doesn't detect this
> condition currently while GCC does.

> Details: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108189

> Fixes errors like:
> progs/btf_dump_test_case_bitfields.c:85:7: error: anonymous struct
> declared inside parameter list will not be visible outside of this
> definition or declaration [-Werror]
> 85 | int f(struct {
> | ^~~~~~

> Signed-off-by: James Hilliard <james.hilliard1@gmail.com>

Acked-by: Stanislav Fomichev <sdf@google.com>

Looking at the referenced thread, seems like it requires at lest C23
and I doubt default clang is using that; so seems fine to be pedantic
here and move the definitions out.

> ---
> .../bpf/progs/btf_dump_test_case_bitfields.c | 9 ++++--
> .../progs/btf_dump_test_case_namespacing.c | 10 ++++---
> .../bpf/progs/btf_dump_test_case_packing.c | 10 ++++---
> .../bpf/progs/btf_dump_test_case_padding.c | 10 ++++---
> .../bpf/progs/btf_dump_test_case_syntax.c | 30 +++++++++++++------
> 5 files changed, 46 insertions(+), 23 deletions(-)

> diff --git
> a/tools/testing/selftests/bpf/progs/btf_dump_test_case_bitfields.c
> b/tools/testing/selftests/bpf/progs/btf_dump_test_case_bitfields.c
> index e01690618e1e..c75f6bd06a49 100644
> --- a/tools/testing/selftests/bpf/progs/btf_dump_test_case_bitfields.c
> +++ b/tools/testing/selftests/bpf/progs/btf_dump_test_case_bitfields.c
> @@ -82,11 +82,16 @@ struct bitfield_flushed {
> long b: 16;
> };

> -int f(struct {
> +/* ----- START-EXPECTED-OUTPUT ----- */
> +struct root_struct {
> struct bitfields_only_mixed_types _1;
> struct bitfield_mixed_with_others _2;
> struct bitfield_flushed _3;
> -} *_)
> +};
> +
> +/* ------ END-EXPECTED-OUTPUT ------ */
> +
> +int f(struct root_struct *_)
> {
> return 0;
> }
> diff --git
> a/tools/testing/selftests/bpf/progs/btf_dump_test_case_namespacing.c
> b/tools/testing/selftests/bpf/progs/btf_dump_test_case_namespacing.c
> index 92a4ad428710..d7cf2a8487c9 100644
> --- a/tools/testing/selftests/bpf/progs/btf_dump_test_case_namespacing.c
> +++ b/tools/testing/selftests/bpf/progs/btf_dump_test_case_namespacing.c
> @@ -49,9 +49,7 @@ typedef int Y;

> typedef int Z;

> -/*------ END-EXPECTED-OUTPUT ------ */
> -
> -int f(struct {
> +struct root_struct {
> struct S _1;
> S _2;
> union U _3;
> @@ -67,7 +65,11 @@ int f(struct {
> X xx;
> Y yy;
> Z zz;
> -} *_)
> +};
> +
> +/*------ END-EXPECTED-OUTPUT ------ */
> +
> +int f(struct root_struct *_)
> {
> return 0;
> }
> diff --git
> a/tools/testing/selftests/bpf/progs/btf_dump_test_case_packing.c
> b/tools/testing/selftests/bpf/progs/btf_dump_test_case_packing.c
> index 7998f27df7dd..e039ceb50c43 100644
> --- a/tools/testing/selftests/bpf/progs/btf_dump_test_case_packing.c
> +++ b/tools/testing/selftests/bpf/progs/btf_dump_test_case_packing.c
> @@ -132,9 +132,7 @@ struct outer_packed_struct {
> struct nested_packed_struct b;
> } __attribute__((packed));

> -/* ------ END-EXPECTED-OUTPUT ------ */
> -
> -int f(struct {
> +struct root_struct {
> struct packed_trailing_space _1;
> struct non_packed_trailing_space _2;
> struct packed_fields _3;
> @@ -147,7 +145,11 @@ int f(struct {
> struct usb_host_endpoint _10;
> struct outer_nonpacked_struct _11;
> struct outer_packed_struct _12;
> -} *_)
> +};
> +
> +/* ------ END-EXPECTED-OUTPUT ------ */
> +
> +int f(struct root_struct *_)
> {
> return 0;
> }
> diff --git
> a/tools/testing/selftests/bpf/progs/btf_dump_test_case_padding.c
> b/tools/testing/selftests/bpf/progs/btf_dump_test_case_padding.c
> index 79276fbe454a..2ca46ad8d66a 100644
> --- a/tools/testing/selftests/bpf/progs/btf_dump_test_case_padding.c
> +++ b/tools/testing/selftests/bpf/progs/btf_dump_test_case_padding.c
> @@ -220,9 +220,7 @@ struct outer_mixed_but_unpacked {
> struct nested_packed b2;
> };

> -/* ------ END-EXPECTED-OUTPUT ------ */
> -
> -int f(struct {
> +struct root_struct {
> struct padded_implicitly _1;
> struct padded_explicitly _2;
> struct padded_a_lot _3;
> @@ -243,7 +241,11 @@ int f(struct {
> struct ib_wc _201;
> struct acpi_object_method _202;
> struct outer_mixed_but_unpacked _203;
> -} *_)
> +} __attribute__((packed));
> +
> +/* ------ END-EXPECTED-OUTPUT ------ */
> +
> +int f(struct root_struct *_)
> {
> return 0;
> }
> diff --git
> a/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c
> b/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c
> index 26fffb02ed10..3e31df7cecc6 100644
> --- a/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c
> +++ b/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c
> @@ -104,24 +104,24 @@ typedef void (*printf_fn_t)(const char *, ...);
> * typedef const fn_output_inner_t fn_ptr_arr2_t[5];
> */
> /* ----- START-EXPECTED-OUTPUT ----- */
> -typedef char * const * (*fn_ptr2_t)(struct {
> - int a;
> -}, int (*)(int));
> +struct struct_a;
> +
> +typedef char * const * (*fn_ptr2_t)(struct struct_a, int (*)(int));
> +
> +struct struct_c;
> +
> +struct struct_h;

> typedef struct {
> int a;
> - void (*b)(int, struct {
> - int c;
> - }, union {
> + void (*b)(int, struct struct_c, union {
> char d;
> int e[5];
> });
> } (*fn_complex_t)(union {
> void *f;
> char g[16];
> -}, struct {
> - int h;
> -});
> +}, struct struct_h);

> typedef void (* (*signal_t)(int, void (*)(int)))(int);

> @@ -272,6 +272,18 @@ struct root_struct {
> struct float_struct _15;
> };

> +struct struct_a {
> + int a;
> +};
> +
> +struct struct_h {
> + int h;
> +};
> +
> +struct struct_c {
> + int c;
> +};
> +
> /* ------ END-EXPECTED-OUTPUT ------ */

> int f(struct root_struct *s)
> --
> 2.34.1