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References: <20230109204520.539080-1-ojeda@kernel.org>
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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Mon, 9 Jan 2023 12:54:24 -0800
Message-ID: <CAKwvOdkr6mAdNOkZqGdkosAN6JABHRU3bHg=K8ujjbw2GxEsKQ@mail.gmail.com>
Subject: Re: [PATCH 1/6] docs: rust: add paragraph about finding a suitable `libclang`
To:     Miguel Ojeda <ojeda@kernel.org>
Cc:     Masahiro Yamada <masahiroy@kernel.org>,
        linux-kbuild@vger.kernel.org,
        Nathan Chancellor <nathan@kernel.org>,
        Nicolas Schier <nicolas@fjasle.eu>,
        rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
        patches@lists.linux.dev, Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>,
        Jonathan Corbet <corbet@lwn.net>, linux-doc@vger.kernel.org
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On Mon, Jan 9, 2023 at 12:45 PM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> Sometimes users need to tweak the finding process of `libclang`
> for `bindgen` via the `clang-sys`-provided environment variables.
>
> Thus add a paragraph to the setting up guide, including a reference
> to `clang-sys`'s relevant documentation.
>
> Link: https://lore.kernel.org/rust-for-linux/CAKwvOdm5JT4wbdQQYuW+RT07rCi6whGBM2iUAyg8A1CmLXG6Nw@mail.gmail.com/
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

This is super helpful for me, since I build clang from source and
would like to use my libclang.so! Thanks for this documentation
Miguel!
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
>  Documentation/rust/quick-start.rst | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
>
> diff --git a/Documentation/rust/quick-start.rst b/Documentation/rust/quick-start.rst
> index 13b7744b1e27..cae21ea7de41 100644
> --- a/Documentation/rust/quick-start.rst
> +++ b/Documentation/rust/quick-start.rst
> @@ -100,6 +100,23 @@ Install it via (note that this will download and build the tool from source)::
>
>         cargo install --locked --version $(scripts/min-tool-version.sh bindgen) bindgen
>
> +``bindgen`` needs to find a suitable ``libclang`` in order to work. If it is
> +not found (or a different ``libclang`` than the one found should be used),
> +the process can be tweaked using the environment variables understood by
> +``clang-sys`` (the Rust bindings crate that ``bindgen`` uses to access
> +``libclang``):
> +
> +* ``LLVM_CONFIG_PATH`` can be pointed to an ``llvm-config`` executable.
> +
> +* Or ``LIBCLANG_PATH`` can be pointed to a ``libclang`` shared library
> +  or to the directoy containing it.
> +
> +* Or ``CLANG_PATH`` can be pointed to a ``clang`` executable.
> +
> +For details, please see ``clang-sys``'s documentation at:
> +
> +       https://github.com/KyleMayes/clang-sys#environment-variables
> +
>
>  Requirements: Developing
>  ------------------------
> --
> 2.39.0
>


-- 
Thanks,
~Nick Desaulniers