From 2a24e2485722b0e12e17a2bd473bd15c9e420bdb Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Mon, 1 Apr 2024 10:07:13 -0700 Subject: [PATCH] bpftool: Use __typeof__() instead of typeof() in BPF skeleton When generated BPF skeleton header is included in C++ code base, some compiler setups will emit warning about using language extensions due to typeof() usage, resulting in something like: error: extension used [-Werror,-Wlanguage-extension-token] obj->struct_ops.empty_tcp_ca = (typeof(obj->struct_ops.empty_tcp_ca)) ^ It looks like __typeof__() is a preferred way to do typeof() with better C++ compatibility behavior, so switch to that. With __typeof__() we get no such warning. Fixes: c2a0257c1edf ("bpftool: Cast pointers for shadow types explicitly.") Fixes: 00389c58ffe9 ("bpftool: Add support for subskeletons") Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: Kui-Feng Lee Acked-by: Quentin Monnet Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20240401170713.2081368-1-andrii@kernel.org --- tools/bpf/bpftool/gen.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c index 786268f1a483..b3979ddc0189 100644 --- a/tools/bpf/bpftool/gen.c +++ b/tools/bpf/bpftool/gen.c @@ -386,7 +386,7 @@ static int codegen_subskel_datasecs(struct bpf_object *obj, const char *obj_name */ needs_typeof = btf_is_array(var) || btf_is_ptr_to_func_proto(btf, var); if (needs_typeof) - printf("typeof("); + printf("__typeof__("); err = btf_dump__emit_type_decl(d, var_type_id, &opts); if (err) @@ -1131,7 +1131,7 @@ static void gen_st_ops_shadow_init(struct btf *btf, struct bpf_object *obj) continue; codegen("\ \n\ - obj->struct_ops.%1$s = (typeof(obj->struct_ops.%1$s))\n\ + obj->struct_ops.%1$s = (__typeof__(obj->struct_ops.%1$s))\n\ bpf_map__initial_value(obj->maps.%1$s, NULL);\n\ \n\ ", ident); -- 2.25.1