Makefile: Make sure all linker input objects exist
In case the build system builds a directory with empty Makefile,
one which does not contain any obj-y entries, the build fails to
link due to missing built-in.o .
This happens because of this part of scripts/Makefile.build
81 ifneq ($(strip $(obj-y) $(obj-m) $(obj-) $(subdir-m) $(lib-target)),)
82 builtin-target := $(obj)/built-in.o
83 endif
which does not assign builtin-target in case obj-y is empty. The
built-in target is then not built at all, and built-in.o is not
generated by this part of scripts/Makefile.build
325 ifdef builtin-target
326 quiet_cmd_link_o_target = AR $@
327 # If the list of objects to link is empty, just create an empty built-in.o
...
335 targets += $(builtin-target)
336 endif # builtin-target
This is the correct behavior.
The final link however expects the built-in.o to exist in every directory
included in the build, even in those where the aforementioned code skipped
generation of built-in.o . Make sure the built-in.o does exist for every
directory used in final link simply by doing touch on every built-in.o used
for the link, which will create empty built-in.o in case any built-in.o is
missing.
A possible alternative fix is the always define the builtin-target
and always generate built-in.o .
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Tested-by: Quentin Schulz <quentin.schulz@cherry.de>
diff --git a/Makefile b/Makefile
index c731895..bcb1fdd 100644
--- a/Makefile
+++ b/Makefile
@@ -1788,6 +1788,7 @@
ifeq ($(LTO_ENABLE),y)
quiet_cmd_u-boot__ ?= LTO $@
cmd_u-boot__ ?= \
+ touch $(u-boot-main) ; \
$(CC) -nostdlib -nostartfiles \
$(LTO_FINAL_LDFLAGS) $(c_flags) \
$(KBUILD_LDFLAGS:%=-Wl,%) $(LDFLAGS_u-boot:%=-Wl,%) -o $@ \
@@ -1801,7 +1802,9 @@
$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
else
quiet_cmd_u-boot__ ?= LD $@
- cmd_u-boot__ ?= $(LD) $(KBUILD_LDFLAGS) $(LDFLAGS_u-boot) -o $@ \
+ cmd_u-boot__ ?= \
+ touch $(u-boot-main) ; \
+ $(LD) $(KBUILD_LDFLAGS) $(LDFLAGS_u-boot) -o $@ \
-T u-boot.lds $(u-boot-init) \
--whole-archive \
$(u-boot-main) \