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

[Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx>]

On Sat, Feb 15, 2025 at 1:57 PM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
>
> I will apply this if Miguel gives Ack.

Thanks Masahiro -- I left some comments above.

This does remove some absolute paths for me, though not all (e.g.
`core.o` that comes from the sysroot). Since it is an improvement
already, if you want to apply it:

Acked-by: Miguel Ojeda <ojeda@xxxxxxxxxx>

I leave below a diff that works for `core.o` for me -- it would do it
in all cases, not just `building_out_of_srctree`, since it is outside
the repository in all cases, which I think makes sense, e.g. in an
in-tree build I get:

    $ strings rust/core.o | grep validations.rs
    lib/rustlib/src/rust/library/core/src/str/validations.rs

Cheers,
Miguel

diff --git a/rust/Makefile b/rust/Makefile
index ea3849eb78f6..42f242472031 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -438,7 +438,7 @@ $(obj)/exports.o: private skip_gendwarfksyms = 1
 $(obj)/core.o: private skip_clippy = 1
 $(obj)/core.o: private skip_flags = -Wunreachable_pub
 $(obj)/core.o: private rustc_objcopy = $(foreach
sym,$(redirect-intrinsics),--redefine-sym $(sym)=__rust$(sym))
-$(obj)/core.o: private rustc_target_flags = $(core-cfgs)
+$(obj)/core.o: private rustc_target_flags = $(core-cfgs)
--remap-path-prefix=$(rustc_sysroot)/=
 $(obj)/core.o: $(RUST_LIB_SRC)/core/src/lib.rs \
     $(wildcard $(objtree)/include/config/RUSTC_VERSION_TEXT) FORCE
        +$(call if_changed_rule,rustc_library)