From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D048853E0C for ; Mon, 1 Apr 2024 19:50:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712001040; cv=none; b=dmF5Qq97T7FFy500hxaFxAQOFolPQ70b/0JwV0kUogCnMf5XyyqouYahhyHS5o8nMyXsx8gmRGGopcWqO18AkeuIISJLdS92NQA73XYuD2wnAV/ZPA0GcF9CDrIwKfTL4yzeWKTDiG8HAoEDv6Y2xCqTO3VL5GXc8KkLXD1941s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712001040; c=relaxed/simple; bh=eByiN90C0tzLm/B0DWkGFX79TdN28GrZdBgxIgeQ5UE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Qo8yQQ0rUaHF7Ii6qRnM3IK19da0j34zLLi9li0Qz5Vw1zRXRKgKI+Dgac6RuiS6mxye0kxuHApR8eOvKRtB5gcgaYNrnbzQfkcXyfatuIY3G6ioqkq6t0xu2cFZMEtvOgrlXQupDWCzggUHdBehRqArhdgeHH/KD9cZ5w37ZiA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=StpxS3ey; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="StpxS3ey" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C27AEC433F1; Mon, 1 Apr 2024 19:50:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712001039; bh=eByiN90C0tzLm/B0DWkGFX79TdN28GrZdBgxIgeQ5UE=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=StpxS3eym56PNjMFXPwlh6jy3IQhmMU+n0TYAKRvjISHXFvOMY4Zfs46K41eMvudy jEdCMkpF8JzH+SauIy99bTzNl0BlBkWhEf0MB7aAn2zqj+Upj3CBtG6T8y6vN52LKw bL5j7QemPvXI9BugHk4UB8YkQCaJjwCUe6r5O0Sbmlp1nCPFnVXSe5Gr3jZoQfyHus v3jOY/+53qIDwm3r/8dzllvZrlAy49A8fYTkdmLTlTn1zUy7KhR29X5ffUsSUsQlU9 YvWO/NfcUdbehibAdg2+kEfjPaUJ2wzsSpu9zDdp1mR3uMocjpHGpYbycfEGBrsQt+ VqasSDSSm14fg== Message-ID: <2dde160c-930c-452e-9107-c9e34f6ebdff@kernel.org> Date: Mon, 1 Apr 2024 20:50:35 +0100 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH bpf-next] bpftool: use __typeof__() instead of typeof() in BPF skeleton To: Kui-Feng Lee , Andrii Nakryiko , bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, martin.lau@kernel.org Cc: kernel-team@meta.com References: <20240401170713.2081368-1-andrii@kernel.org> From: Quentin Monnet Content-Language: en-GB In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 01/04/2024 18:59, Kui-Feng Lee wrote: > > > On 4/1/24 10:07, Andrii Nakryiko wrote: >> 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 >> --- >>   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); > > > LGTM! > > Acked-by: Kui-Feng Lee > > Thanks! > Acked-by: Quentin Monnet