From da7a35062bcccd3f67779a357065ba707b02ff2b Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Sun, 19 Jul 2020 23:17:41 -0700 Subject: [PATCH] libbpf bpf_helpers: Use __builtin_offsetof for offsetof 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 Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200720061741.1514673-1-irogers@google.com --- 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) \ -- 2.20.1