The non-builtin route for offsetof has a dependency on size_t from
stdlib.h/stdint.h that is undeclared and may break targets.
The offsetof macro in bpf_helpers may disable the same macro in other
headers that have a #ifdef offsetof guard. Rather than add additional
dependencies improve the offsetof macro declared here to use the
builtin that is available since llvm 3.7 (the first with a BPF backend).
Signed-off-by: Ian Rogers <[email protected]>
---
tools/lib/bpf/bpf_helpers.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index a510d8ed716f..bc14db706b88 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -40,7 +40,7 @@
* Helper macro to manipulate data structures
*/
#ifndef offsetof
-#define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER)
+#define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE, MEMBER)
#endif
#ifndef container_of
#define container_of(ptr, type, member) \
--
2.28.0.rc0.105.gf9edc3c819-goog
On Sun, Jul 19, 2020 at 11:18 PM Ian Rogers <[email protected]> wrote:
>
> The non-builtin route for offsetof has a dependency on size_t from
> stdlib.h/stdint.h that is undeclared and may break targets.
> The offsetof macro in bpf_helpers may disable the same macro in other
> headers that have a #ifdef offsetof guard. Rather than add additional
> dependencies improve the offsetof macro declared here to use the
> builtin that is available since llvm 3.7 (the first with a BPF backend).
>
> Signed-off-by: Ian Rogers <[email protected]>
> ---
Acked-by: Andrii Nakryiko <[email protected]>
> tools/lib/bpf/bpf_helpers.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
> index a510d8ed716f..bc14db706b88 100644
> --- a/tools/lib/bpf/bpf_helpers.h
> +++ b/tools/lib/bpf/bpf_helpers.h
> @@ -40,7 +40,7 @@
> * Helper macro to manipulate data structures
> */
> #ifndef offsetof
> -#define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER)
> +#define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE, MEMBER)
> #endif
> #ifndef container_of
> #define container_of(ptr, type, member) \
> --
> 2.28.0.rc0.105.gf9edc3c819-goog
>
On Sun, Jul 19, 2020 at 11:21 PM Andrii Nakryiko
<[email protected]> wrote:
>
> On Sun, Jul 19, 2020 at 11:18 PM Ian Rogers <[email protected]> wrote:
> >
> > The non-builtin route for offsetof has a dependency on size_t from
> > stdlib.h/stdint.h that is undeclared and may break targets.
> > The offsetof macro in bpf_helpers may disable the same macro in other
> > headers that have a #ifdef offsetof guard. Rather than add additional
> > dependencies improve the offsetof macro declared here to use the
> > builtin that is available since llvm 3.7 (the first with a BPF backend).
> >
> > Signed-off-by: Ian Rogers <[email protected]>
> > ---
>
> Acked-by: Andrii Nakryiko <[email protected]>
Applied. Thanks