Re: [PATCH v2 0/3] Inline helpers into Rust without full LTO

[David Gow]

Le 23/03/2026 à 3:21 AM, Miguel Ojeda a écrit :
> On Tue, 03 Feb 2026 11:34:07 +0000 Alice Ryhl <aliceryhl@xxxxxxxxxx> wrote:
> > To get rid of these helper symbols, provide functionality to inline
> > helpers into Rust using llvm-link. This option complements full LTO, by
> > being much cheaper and avoiding incompatibility with BTF.
>
> I have been testing this. I think we can go ahead with it, with a few
> notes.
>
> I will reply to a couple other bindings in separate emails to avoid
> spamming people too much.
>
>    - I will mark the Kconfig option as "(EXPERIMENTAL)", since that is
>      what the commit message says and it allows us to be a bit
>      conservative.
>
>
>    - Clang passes `-Werror=unused-command-line-argument`, which means
>      under arm (i.e. 32-bit) we get:
>
>        clang: error: argument unused during compilation: '-U arm' [-Werror,-Wunused-command-line-argument]
>
>      And under UML I see:
>
>        clang: error: argument unused during compilation: '-I ./arch/um/include/shared' [-Werror,-Wunused-command-line-argument]
>        clang: error: argument unused during compilation: '-I ./arch/x86/um/shared' [-Werror,-Wunused-command-line-argument]
>        clang: error: argument unused during compilation: '-I ./arch/um/include/shared/skas' [-Werror,-Wunused-command-line-argument]
>
>      So we would need e.g. `-Wno-unused-command-line-argument` there
>      close to the `-Wno-override-module` one, unless Kbuild or
>      ClangBuiltLinux thinks it is important to keep it for this case.
>
>      On the other hand, regardless of whether we fix this (and another
>      issue in a separate email found thanks to the UML build), we could
>      instead add `depends on` listing explicitly the architectures where
>      this is going to be actually tested. That way maintainers can decide
>      whether they want to support it when they are ready. Thoughts?
>
>      Cc'ing Nathan, Nicolas, Nick, Bill, Justin, David, UML, ARM.
I'm quite happy personally to just have 
-Wno-unused-command-line-argument here, given that it otherwise is 
working pretty well on UML and 32-bit UML.

That being said, I expect it won't get a lot of testing (regardless of 
architecture) while it's hidden behind CONFIG_EXPERT.

Cheers,
-- David