modpost: invoke modpost only when input files are updated
Currently, the second pass of modpost is always invoked when you run
'make' or 'make modules' even if none of modules is changed.
Use if_changed to invoke it only when it is necessary.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 896c799..f29a021 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -90,7 +90,7 @@
# modpost options for modules (both in-kernel and external)
MODPOST += \
- $(addprefix -i ,$(input-symdump)) \
+ $(addprefix -i ,$(wildcard $(input-symdump))) \
$(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N)
# 'make -i -k' ignores compile errors, and builds as many modules as possible.
@@ -98,13 +98,18 @@
MODPOST += -n
endif
+$(input-symdump):
+ @:
+
# Read out modules.order to pass in modpost.
# Otherwise, allmodconfig would fail with "Argument list too long".
quiet_cmd_modpost = MODPOST $@
- cmd_modpost = sed 's/ko$$/o/' $(MODORDER) | $(MODPOST) -T -
+ cmd_modpost = sed 's/ko$$/o/' $< | $(MODPOST) -T -
-$(output-symdump): FORCE
- $(call cmd,modpost)
+$(output-symdump): $(MODORDER) $(input-symdump) FORCE
+ $(call if_changed,modpost)
+
+targets += $(output-symdump)
__modpost: $(output-symdump)
ifneq ($(KBUILD_MODPOST_NOFINAL),1)
@@ -114,6 +119,13 @@
PHONY += FORCE
FORCE:
+existing-targets := $(wildcard $(sort $(targets)))
+
+-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
+
+PHONY += FORCE
+FORCE:
+
endif
.PHONY: $(PHONY)