This commit makes -fmacro-prefix-map work for external modules built in
a separate output directory. It improves the reproducibility of external
modules and provides the benefits described in commit a73619a845d5
("kbuild: use -fmacro-prefix-map to make __FILE__ a relative path").
When building_out_of_srctree is not defined (e.g., when the kernel or
external module is built in the source directory), this option is
unnecessary.
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Reviewed-by: Nicolas Schier <nicolas@xxxxxxxxx>
---
Changes in v2:
- Check building_out_of_srctree instead of VPATH
Makefile | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/Makefile b/Makefile
index 38ce19747728..5488aa96b46b 100644
--- a/Makefile
+++ b/Makefile
@@ -1041,8 +1041,10 @@ ifdef CONFIG_CC_IS_GCC
KBUILD_CFLAGS += -fconserve-stack
endif
-# change __FILE__ to the relative path from the srctree
-KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
+# change __FILE__ to the relative path to the source directory
+ifdef building_out_of_srctree
+KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srcroot)/=)
+endif
# include additional Makefiles when needed
include-y := scripts/Makefile.extrawarn
--
2.43.0
