Re: [PATCH bpf v2] libbpf: Handle GCC built-in types for Arm NEON

From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>, Martin Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	Andrii Nakryiko <andriin@fb.com>,
	john fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>, bpf <bpf@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	Jakov Petrina <jakov.petrina@sartura.hr>
Subject: Re: [PATCH bpf v2] libbpf: Handle GCC built-in types for Arm NEON
Date: Wed, 12 Aug 2020 18:12:57 -0700	[thread overview]
Message-ID: <CAADnVQ+sw4p0O5E8UiU=wh-yN69pW6z1jeWUEU5ig1xRbk0fxQ@mail.gmail.com> (raw)
In-Reply-To: <CAEf4BzZKEfgHSeZMMHfGt=WvcChuDh+a_0pyBbwU3riKSt2z5w@mail.gmail.com>

On Wed, Aug 12, 2020 at 10:35 AM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Wed, Aug 12, 2020 at 7:42 AM Jean-Philippe Brucker
> <jean-philippe@linaro.org> wrote:
> >
> > When building Arm NEON (SIMD) code from lib/raid6/neon.uc, GCC emits
> > DWARF information using a base type "__Poly8_t", which is internal to
> > GCC and not recognized by Clang. This causes build failures when
> > building with Clang a vmlinux.h generated from an arm64 kernel that was
> > built with GCC.
> >
> >         vmlinux.h:47284:9: error: unknown type name '__Poly8_t'
> >         typedef __Poly8_t poly8x16_t[16];
> >                 ^~~~~~~~~
> >
> > The polyX_t types are defined as unsigned integers in the "Arm C
> > Language Extension" document (101028_Q220_00_en). Emit typedefs based on
> > standard integer types for the GCC internal types, similar to those
> > emitted by Clang.
> >
> > Including linux/kernel.h to use ARRAY_SIZE() incidentally redefined
> > max(), causing a build bug due to different types, hence the seemingly
> > unrelated change.
> >
> > Reported-by: Jakov Petrina <jakov.petrina@sartura.hr>
> > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > ---
>
> LGTM.
>
> Acked-by: Andrii Nakryiko <andriin@fb.com>

Applied. Thanks