Re: [PATCH v8] kbuild: host: use single executable for rustc -C linker

[Nathan Chancellor]

Hi Mohamad,

On Sat, May 09, 2026 at 01:19:38PM +0300, Mohamad Alsadhan wrote:
> rustc's -C linker= option expects a single executable path. When
> HOSTCC contains a wrapper (e.g. "ccache gcc"), passing
> `-Clinker=$(HOSTCC)` results in the shell splitting the value into
> multiple words, and rustc interprets the additional word as an
> input filename:
> 
>   error: multiple input filenames provided ...
> 
> Generate a small wrapper script and pass it to -Clinker e.g.
> 
>   ```
>   #!/bin/sh
>   ccache gcc "$@"
>   ```
> 
> Note that the wrapper intentionally avoids a leading `exec` to
> naturally support leading environment assignments such as:
> `VAR=VAL ccache gcc`.
> 
> This fix should be general enough to address most if not all cases
> (incl. wrappers or subcommands) and avoids surprises of simpler fixes
> like just defaulting to gcc.
> 
> This avoids passing the user command as an environment variable as
> that would be more challenging to trace and debug shell expansions.
> 
> Link: https://github.com/Rust-for-Linux/linux/issues/1224
> Suggested-by: Yoann Congal <yoann.congal@xxxxxxxx>
> Signed-off-by: Mohamad Alsadhan <mo@xxxxxxx>

Thanks, this seems reasonable from a Kbuild perspective (although
Nicolas may have other comments) and it appears to work for me. I expect
this to go via the Rust tree.

Acked-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx>

> diff --git a/Makefile b/Makefile
> index 1a219bf1c..5ebeef67f 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1651,7 +1651,8 @@ CLEAN_FILES += vmlinux.symvers modules-only.symvers \
>  	       modules.builtin.ranges vmlinux.o.map vmlinux.unstripped \
>  	       compile_commands.json rust/test \
>  	       rust-project.json .vmlinux.objs .vmlinux.export.c \
> -               .builtin-dtbs-list .builtin-dtb.S
> +               .builtin-dtbs-list .builtin-dtb.S \
> +	       scripts/rustc-wrapper

What tree was this generated against? It conflicts with Linus's tree due
to commit a76e30c2479c ("kbuild: Delete .builtin-dtbs.S when running
make clean") that landed in 7.0-rc6.

>  
>  # Directories & files removed with 'make mrproper'
>  MRPROPER_FILES += include/config include/generated          \

-- 
Cheers,
Nathan