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/arch/sandbox/config.mk b/arch/sandbox/config.mk
index 4058438..dd9b747 100644
--- a/arch/sandbox/config.mk
+++ b/arch/sandbox/config.mk
@@ -22,7 +22,9 @@
endif
KBUILD_CFLAGS += $(SANITIZERS)
-cmd_u-boot__ = $(CC) -o $@ -Wl,-T u-boot.lds $(u-boot-init) \
+cmd_u-boot__ = \
+ touch $(u-boot-main) ; \
+ $(CC) -o $@ -Wl,-T u-boot.lds $(u-boot-init) \
$(KBUILD_LDFLAGS:%=-Wl,%) \
$(SANITIZERS) \
$(LTO_FINAL_LDFLAGS) \
@@ -32,7 +34,9 @@
-Wl,--no-whole-archive \
$(PLATFORM_LIBS) -Wl,-Map -Wl,u-boot.map -Wl,--gc-sections
-cmd_u-boot-spl = (cd $(obj) && $(CC) -o $(SPL_BIN) -Wl,-T u-boot-spl.lds \
+cmd_u-boot-spl = (cd $(obj) && \
+ touch $(patsubst $(obj)/%,%,$(u-boot-spl-main)) && \
+ $(CC) -o $(SPL_BIN) -Wl,-T u-boot-spl.lds \
$(KBUILD_LDFLAGS:%=-Wl,%) \
$(SANITIZERS) \
$(LTO_FINAL_LDFLAGS) \