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Subject: Re: [PATCH] bpf: Replace deprecated -target with --target= for Clang
To:     Quentin Monnet <quentin@isovalent.com>,
        Fangrui Song <maskray@google.com>,
        Alexei Starovoitov <ast@kernel.org>,
        John Fastabend <john.fastabend@gmail.com>, bpf@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, llvm@lists.linux.dev
References: <20230623020908.1410959-1-maskray@google.com>
 <a5d419e4-f2ea-27f6-9259-a7b6486ab616@isovalent.com>
From:   Daniel Borkmann <daniel@iogearbox.net>
Message-ID: <bab57007-ddf6-7134-cefd-dfd1c8be17be@iogearbox.net>
Date:   Fri, 23 Jun 2023 13:30:00 +0200
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On 6/23/23 10:51 AM, Quentin Monnet wrote:
> 2023-06-23 02:09 UTC+0000 ~ Fangrui Song <maskray@google.com>
>> -target has been deprecated since Clang 3.4 in 2013. Use the preferred
>> --target=bpf form instead. This matches how we use --target= in
>> scripts/Makefile.clang.
> 
> This seems to be the relevant commit, for reference:
> 
> https://github.com/llvm/llvm-project/commit/274b6f0c87a6a1798de0a68135afc7f95def6277
> 
>>
>> Signed-off-by: Fangrui Song <maskray@google.com>
>> ---
>>   Documentation/bpf/bpf_devel_QA.rst              | 10 +++++-----
>>   Documentation/bpf/btf.rst                       |  4 ++--
>>   Documentation/bpf/llvm_reloc.rst                |  6 +++---
>>   drivers/hid/bpf/entrypoints/Makefile            |  2 +-
>>   kernel/bpf/preload/iterators/Makefile           |  2 +-
>>   samples/bpf/Makefile                            |  6 +++---
>>   samples/bpf/gnu/stubs.h                         |  3 ++-
>>   samples/bpf/test_lwt_bpf.sh                     |  2 +-
>>   samples/hid/Makefile                            |  6 +++---
>>   tools/bpf/bpftool/Documentation/bpftool-gen.rst |  4 ++--
>>   tools/bpf/bpftool/Makefile                      |  2 +-
>>   tools/bpf/runqslower/Makefile                   |  2 +-
>>   tools/build/feature/Makefile                    |  2 +-
>>   tools/perf/Documentation/perf-config.txt        |  2 +-
>>   tools/perf/Makefile.perf                        |  4 ++--
>>   tools/perf/util/llvm-utils.c                    |  4 ++--
>>   tools/testing/selftests/bpf/Makefile            |  6 +++---
>>   tools/testing/selftests/bpf/gnu/stubs.h         |  3 ++-
>>   tools/testing/selftests/hid/Makefile            |  6 +++---
>>   tools/testing/selftests/net/Makefile            |  4 ++--
>>   tools/testing/selftests/tc-testing/Makefile     |  2 +-
>>   21 files changed, 42 insertions(+), 40 deletions(-)
>>
> 
>> diff --git a/samples/bpf/gnu/stubs.h b/samples/bpf/gnu/stubs.h
>> index 719225b16626..cc37155fbfa5 100644
>> --- a/samples/bpf/gnu/stubs.h
>> +++ b/samples/bpf/gnu/stubs.h
>> @@ -1 +1,2 @@
>> -/* dummy .h to trick /usr/include/features.h to work with 'clang -target bpf' */
>> +/* SPDX-License-Identifier: GPL-2.0 */
> 
> Are these necessary, seeing that the files only contain this single-line
> comment?

Yeah, lets drop that one. Otherwise looks good. Could you split out the tools/perf/
changes into a separate commit? I would assume that Arnaldo wants to take these
changes via perf tree instead.

>> +/* dummy .h to trick /usr/include/features.h to work with 'clang --target=bpf' */
> 
> Other than this, the change looks good, thanks. Although it should
> probably target bpf-next rather than bpf?
> 
> Acked-by: Quentin Monnet <quentin@isovalent.com>