On Wed, Jun 8, 2022 at 11:24 PM James Hilliard
<james.hilliard1@xxxxxxxxx> wrote:
>
> It seems the gcc preprocessor breaks unless pragmas are wrapped
> individually inside macros when surrounding __attribute__.
>
> Fixes errors like:
> error: expected identifier or '(' before '#pragma'
> 106 | SEC("cgroup/bind6")
> | ^~~
>
> error: expected '=', ',', ';', 'asm' or '__attribute__' before '#pragma'
> 114 | char _license[] SEC("license") = "GPL";
> | ^~~
>
> Signed-off-by: James Hilliard <james.hilliard1@xxxxxxxxx>
> ---
> Changes v2 -> v3:
> - just fix SEC pragma
> Changes v1 -> v2:
> - replace typeof with __typeof__ instead of changing pragma macros
> ---
> tools/lib/bpf/bpf_helpers.h | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
> index fb04eaf367f1..66d23c47c206 100644
> --- a/tools/lib/bpf/bpf_helpers.h
> +++ b/tools/lib/bpf/bpf_helpers.h
> @@ -22,11 +22,12 @@
> * To allow use of SEC() with externs (e.g., for extern .maps declarations),
> * make sure __attribute__((unused)) doesn't trigger compilation warning.
> */
> +#define DO_PRAGMA(x) _Pragma(#x)
> #define SEC(name) \
> - _Pragma("GCC diagnostic push") \
> - _Pragma("GCC diagnostic ignored \"-Wignored-attributes\"") \
> + DO_PRAGMA("GCC diagnostic push") \
> + DO_PRAGMA("GCC diagnostic ignored \"-Wignored-attributes\"") \
> __attribute__((section(name), used)) \
> - _Pragma("GCC diagnostic pop") \
> + DO_PRAGMA("GCC diagnostic pop") \
>
I'm not going to accept this unless I can repro it in the first place.
Using -std=c17 doesn't trigger such issue. Please provide the repro
first. Building systemd is not a repro, unfortunately. Please try to
do it based on libbpf-bootstrap ([0])
[0] https://github.com/libbpf/libbpf-bootstrap
> /* Avoid 'linux/stddef.h' definition of '__always_inline'. */
> #undef __always_inline
> --
> 2.25.1
>
