Re: [PATCH v2] kbuild, rust: use -fremap-path-prefix to make paths relative

[Gary Guo <gary@garyguo.net>]

On Wed, 19 Feb 2025 22:22:13 +0100
Thomas Weißschuh <linux@weissschuh.net> wrote:

> Remap source path prefixes in all output, including compiler
> diagnostics, debug information, macro expansions, etc.
> This removes a few absolute paths from the binary and also makes it
> possible to use core::panic::Location properly.
> 
> Equivalent to the same configuration done for C sources in
> commit 1d3730f0012f ("kbuild: support -fmacro-prefix-map for external modules")
> and commit a73619a845d5 ("kbuild: use -fmacro-prefix-map to make __FILE__ a relative path").
> 
> Link: https://doc.rust-lang.org/rustc/command-line-arguments.html#--remap-path-prefix-remap-source-names-in-output
> Acked-by: Miguel Ojeda <ojeda@kernel.org>
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
> ---
> Changes in v2:
> - Drop the usage of $(call rustc-option)
> - Link to v1: https://lore.kernel.org/r/20250210-rust-path-remap-v1-1-021c48188df1@weissschuh.net
> ---
>  Makefile | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/Makefile b/Makefile
> index 9e0d63d9d94b90672f91929e5e148e5a0c346cb6..9ed2222fafd4fa37a367b87a5c681936368318e7 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1068,6 +1068,7 @@ endif
>  # change __FILE__ to the relative path to the source directory
>  ifdef building_out_of_srctree
>  KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srcroot)/=)
> +KBUILD_RUSTFLAGS += --remap-path-prefix=$(srcroot)/=
>  endif
>  
>  # include additional Makefiles when needed
> 
> ---
> base-commit: beeb78d46249cab8b2b8359a2ce8fa5376b5ad2d
> change-id: 20250210-rust-path-remap-e97cec71e61a
> 
> Best regards,

Hi Thomas,

Thanks for sending this. I can confirm that this is working as
intended, and it also fixes my language server error reporting when
building out of srctree. So,

Tested-by: Gary Guo <gary@garyguo.net>

Best,
Gary