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Subject: Re: [PATCH] Documentation: add minimum clang/llvm version
To:     Nathan Chancellor <natechancellor@gmail.com>,
        Nick Desaulniers <ndesaulniers@google.com>
Cc:     Masahiro Yamada <masahiroy@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        Jonathan Corbet <corbet@lwn.net>,
        Randy Dunlap <rdunlap@infradead.org>,
        Theodore Ts'o <tytso@mit.edu>,
        Kees Cook <keescook@chromium.org>,
        Will Deacon <will@kernel.org>, Borislav Petkov <bp@suse.de>,
        "Alexander A. Klimov" <grandmaster@al2klimov.de>,
        clang-built-linux@googlegroups.com, linux-kbuild@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20200825222552.3113760-1-ndesaulniers@google.com>
 <20200825225131.GA2702183@ubuntu-n2-xlarge-x86>
From:   "Gustavo A. R. Silva" <gustavo@embeddedor.com>
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Message-ID: <8e867824-48ca-f63a-c863-d4ce9f9ebf75@embeddedor.com>
Date:   Tue, 25 Aug 2020 18:04:09 -0500
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On 8/25/20 17:51, Nathan Chancellor wrote:
> On Tue, Aug 25, 2020 at 03:25:51PM -0700, Nick Desaulniers wrote:
>> Based on a vote at the LLVM BoF at Plumbers 2020, we decided to start
>> small, supporting just one formal upstream release of LLVM for now.
>>
>> We can probably widen the support window of supported versions over
>> time.  Also, note that LLVM's release process is different than GCC's.
>> GCC tends to have 1 major release per year while releasing minor updates
>> to the past 3 major versions.  LLVM tends to support one major release
>> and one minor release every six months.
>>
>> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
>> ---
>> Note to reviewers: working remote, I'm having trouble testing/verifying
>> that I have the RST links wired up correctly; I would appreciate it if
>> someone is able to `make htmldocs` and check
>> Documentation/output/process/changes.html properly links to
>> Documentation/output/kbuild/llvm.html.
> 
> I ran 'make O=out htmldocs' and can confirm that the link works properly
> in process/changes.html, pointing to kbuild/llvm.html.
> 

The same here.

Tested-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
--
Gustavo

>>  Documentation/kbuild/llvm.rst     |  2 ++
>>  Documentation/process/changes.rst | 10 ++++++++++
>>  2 files changed, 12 insertions(+)
>>
>> diff --git a/Documentation/kbuild/llvm.rst b/Documentation/kbuild/llvm.rst
>> index 2aac50b97921..70ec6e9a183b 100644
>> --- a/Documentation/kbuild/llvm.rst
>> +++ b/Documentation/kbuild/llvm.rst
>> @@ -1,3 +1,5 @@
>> +.. _kbuild_llvm:
>> +
>>  ==============================
>>  Building Linux with Clang/LLVM
>>  ==============================
>> diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
>> index ee741763a3fc..6c580ef9f2a3 100644
>> --- a/Documentation/process/changes.rst
>> +++ b/Documentation/process/changes.rst
>> @@ -30,6 +30,7 @@ you probably needn't concern yourself with pcmciautils.
>>          Program        Minimal version       Command to check the version
>>  ====================== ===============  ========================================
>>  GNU C                  4.9              gcc --version
>> +Clang/LLVM (optional)  10.0.1           clang --version
> 
> Maybe it is worth making the "(optional)" a footnote like Sphinx? Seems
> to just kind of stick out to me but I do not have a strong opinion
> unless others do.
> 
>>  GNU make               3.81             make --version
>>  binutils               2.23             ld -v
>>  flex                   2.5.35           flex --version
>> @@ -68,6 +69,15 @@ GCC
>>  The gcc version requirements may vary depending on the type of CPU in your
>>  computer.
>>  
>> +Clang/LLVM (optional)
>> +---------------------
>> +
>> +The latest formal release of clang and LLVM utils (according to
>> +`releases.llvm.org <https://releases.llvm.org>`_) are supported for building
>> +kernels. Older releases aren't gauranteed to work, and we may drop workarounds
>> +from the kernel that were used to support older versions. Please see additional
>> +docs on :ref:`Building Linux with Clang/LLVM <kbuild_llvm>`.
>> +
> 
> Do we maybe want to add a section for LLVM/clang in the "Getting updated
> software" section? Maybe just a link to the existing section that we
> have in kbuild/llvm.rst?
> 
>>  Make
>>  ----
>>  
>> -- 
>> 2.28.0.297.g1956fa8f8d-goog
>>
> 
> Regardless of the nits above:
> 
> Reviewed-and-tested-by: Nathan Chancellor <natechancellor@gmail.com>
>