[PATCH AUTOSEL 6.14 1/3] kbuild, rust: use -fremap-path-prefix to make paths relative

[Sasha Levin <sashal@kernel.org>]

From: Thomas Weißschuh <linux@weissschuh.net>

[ Upstream commit dbdffaf50ff9cee3259a7cef8a7bd9e0f0ba9f13 ]

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>
Tested-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Makefile b/Makefile
index 8b6764d44a610..c4eeb97ab3df2 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
-- 
2.39.5