Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20220805154231.31257-1-ojeda@kernel.org> <20220805154231.31257-21-ojeda@kernel.org>
 <CAKwvOdndYxQ+KgVhC8F3vWnHDT8pD3px8cKjinu-khn25_FSYw@mail.gmail.com>
In-Reply-To: <CAKwvOdndYxQ+KgVhC8F3vWnHDT8pD3px8cKjinu-khn25_FSYw@mail.gmail.com>
From:   Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Date:   Tue, 23 Aug 2022 14:12:31 +0200
Message-ID: <CANiq72nA0WwfnSaNxxz27iM5LXPELQVzTAQGBE30SXeLGVEf1A@mail.gmail.com>
Subject: Re: [PATCH v9 20/27] scripts: add `rust_is_available.sh`
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Miguel Ojeda <ojeda@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, patches@lists.linux.dev,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@google.com>,
        Finn Behrens <me@kloenk.de>, Miguel Cano <macanroj@gmail.com>,
        Tiago Lam <tiagolam@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>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Mon, Aug 22, 2022 at 10:09 PM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> because I'm using clang built from source from ToT.  Is this supposed
> to mean that I can't use clang-16, clang-14, clang-13, clang-12, or
> clang-11 (in the kernel we support clang-11+) in order to use rust?
> I'm guessing that's going to hinder adoption.  Is there a way to

No, it is only a warning, so you can proceed if you want to risk it.

However, is there a reason you would like to mix the versions?

If not, please point `bindgen` to your newer libclang (see below).

> specify which libclang version bindgen should be using?

Yes, see below.

> I have libclang built in my clang sources,
> llvm-project/llvm/build/lib/libclang.so.  I also tried:
>
> $ CLANG_PATH=/android0/llvm-project/llvm/build/lib/libclang.so.15 make
> LLVM=1 -j72 rustavailable

`CLANG_PATH` is for pointing to a `clang` executable, not `libclang`.

Instead, please try `LIBCLANG_PATH` (note the `LIB` there).

For instance, using the test header to print the libclang version,
this works for me:

    $ bindgen scripts/rust_is_available_bindgen_libclang.h
    ... clang version 14.0.6 (https://github.com/llvm/llvm-project.git ...

    $ LIBCLANG_PATH=.../libclang-6.0.so.1 \
      bindgen scripts/rust_is_available_bindgen_libclang.h
    ... clang version 6.0.0 (tags/RELEASE_600/final) ...

If the above does not work, for details on how the dependency is
resolved, please see:

    https://github.com/KyleMayes/clang-sys#linking
    https://github.com/KyleMayes/clang-sys#dependencies
    https://github.com/KyleMayes/clang-sys#environment-variables
    https://github.com/rust-lang/rust-bindgen#environment-variables

I will add a note about this to the docs.

Cheers,
Miguel