[PATCH v3 bpf-next 03/18] libbpf: suppress compiler warning when using SEC() macro with externs
From: Andrii Nakryiko <andrii@kernel.org>
Date: 2021-04-23 18:14:05
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [library] (libbpf), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
When used on externs SEC() macro will trigger compilation warning about inapplicable `__attribute__((used))`. That's expected for extern declarations, so suppress it with the corresponding _Pragma. Acked-by: Yonghong Song <redacted> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> --- tools/lib/bpf/bpf_helpers.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index b904128626c2..75c7581b304c 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h@@ -25,9 +25,16 @@ /* * Helper macro to place programs, maps, license in * different sections in elf_bpf file. Section names - * are interpreted by elf_bpf loader + * are interpreted by libbpf depending on the context (BPF programs, BPF maps, + * extern variables, etc). + * To allow use of SEC() with externs (e.g., for extern .maps declarations), + * make sure __attribute__((unused)) doesn't trigger compilation warning. */ -#define SEC(NAME) __attribute__((section(NAME), used)) +#define SEC(name) \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wignored-attributes\"") \ + __attribute__((section(name), used)) \ + _Pragma("GCC diagnostic pop") \ /* Avoid 'linux/stddef.h' definition of '__always_inline'. */ #undef __always_inline
--
2.30.2