Hi Cupetino,
On 1/8/24 03:05, Cupertino Miranda wrote:
> Hi everyone,
>
> This patch address the problem reported in:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113225
>
> Looking forward to your review.
LGTM, thanks. Please apply.
>
> Cheers,
> Cupertino
>
>
> This patch fix a problem with kernel_helper attribute BTF information,
> which incorrectly generates BTF_KIND_FUNC entry.
> This BTF entry although accurate with traditional extern function
> declarations, once the function is attributed with kernel_helper, it is
> semantically incompatible of the kernel helpers in BPF infrastructure.
>
> gcc/ChangeLog:
> PR target/113225
> * btfout.cc (btf_collect_datasec): Skip creating BTF info for
> extern and kernel_helper attributed function decls.
> gcc/testsuite/ChangeLog:
> * gcc.target/bpf/attr-kernel-helper.c: New test.
> ---
> gcc/btfout.cc | 7 +++++++
> gcc/testsuite/gcc.target/bpf/attr-kernel-helper.c | 15 +++++++++++++++
> 2 files changed, 22 insertions(+)
> create mode 100644 gcc/testsuite/gcc.target/bpf/attr-kernel-helper.c
>
> diff --git a/gcc/btfout.cc b/gcc/btfout.cc
> index 04218adc9e66..39e7bec43bfb 100644
> --- a/gcc/btfout.cc
> +++ b/gcc/btfout.cc
> @@ -35,6 +35,8 @@ along with GCC; see the file COPYING3. If not see
> #include "diagnostic-core.h"
> #include "cgraph.h"
> #include "varasm.h"
> +#include "stringpool.h"
> +#include "attribs.h"
> #include "dwarf2out.h" /* For lookup_decl_die. */
>
> static int btf_label_num;
> @@ -429,6 +431,11 @@ btf_collect_datasec (ctf_container_ref ctfc)
> if (dtd == NULL)
> continue;
>
> + if (DECL_EXTERNAL (func->decl)
> + && (lookup_attribute ("kernel_helper",
> + DECL_ATTRIBUTES (func->decl))) != NULL_TREE)
> + continue;
> +
> /* Functions actually get two types: a BTF_KIND_FUNC_PROTO, and
> also a BTF_KIND_FUNC. But the CTF container only allocates one
> type per function, which matches closely with BTF_KIND_FUNC_PROTO.
> diff --git a/gcc/testsuite/gcc.target/bpf/attr-kernel-helper.c
> b/gcc/testsuite/gcc.target/bpf/attr-kernel-helper.c
> new file mode 100644
> index 000000000000..7c5a0007c979
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/attr-kernel-helper.c
> @@ -0,0 +1,15 @@
> +/* Basic test for kernel_helper attribute BTF information. */
> +
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -dA -gbtf" } */
> +
> +extern int foo_helper(int) __attribute((kernel_helper(42)));
> +extern int foo_nohelper(int);
> +
> +int bar (int arg)
> +{
> + return foo_helper (arg) + foo_nohelper (arg);
> +}
> +
> +/* { dg-final { scan-assembler-times "BTF_KIND_FUNC 'foo_nohelper'" 1 } } */
> +/* { dg-final { scan-assembler-times "BTF_KIND_FUNC 'foo_helper'" 0 } } */
