Commit 48f1f058 authored by Sam Ravnborg's avatar Sam Ravnborg Committed by Sam Ravnborg
Browse files

kbuild: consistently decide when to rebuild a target 



Consistently decide when to rebuild a target across all of
if_changed, if_changed_dep, if_changed_rule.
PHONY targets are now treated alike (ignored) for all targets

While add it make Kbuild.include almost readable by factoring out a few
bits to some common variables and reuse this in Makefile.build.

Signed-off-by: default avatarSam Ravnborg <sam@ravnborg.org>
parent d3660a8c

scripts/Kbuild.include

+30 −22
Original line number Diff line number Diff line
@@ -7,10 +7,14 @@ squote := ' 
empty   :=

space   := $(empty) $(empty)



###

# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o

dot-target = $(dir $@).$(notdir $@)



###

# The temporary file to save gcc -MD generated dependencies must not

# contain a comma

depfile = $(subst $(comma),_,$(@D)/.$(@F).d)

depfile = $(subst $(comma),_,$(dot-target).d)



###

# filename of target with directory and extension stripped
@@ -119,40 +123,44 @@ objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o))) 
ifneq ($(KBUILD_NOCMDDEP),1)

# Check if both arguments has same arguments. Result in empty string if equal

# User may override this check using make KBUILD_NOCMDDEP=1

arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )

arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \

                    $(filter-out $(cmd_$@),   $(cmd_$(1))) )

endif



# echo command. Short version is $(quiet) equals quiet, otherwise full command

echo-cmd = $(if $($(quiet)cmd_$(1)), \

	echo '  $(call escsq,$($(quiet)cmd_$(1)))';)



# >'< substitution is for echo to work,

# >$< substitution to preserve $ when reloading .cmd file

# note: when using inline perl scripts [perl -e '...$$t=1;...']

# in $(cmd_xxx) double $$ your perl vars

make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))



# function to only execute the passed command if necessary

# >'< substitution is for echo to work, >$< substitution to preserve $ when reloading .cmd file

# note: when using inline perl scripts [perl -e '...$$t=1;...'] in $(cmd_xxx) double $$ your perl vars

# Find any prerequisites that is newer than target or that does not exist.

# PHONY targets skipped in both cases.

any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)



# Execute command if command has changed or prerequisitei(s) are updated

#

if_changed = $(if $(strip $(filter-out $(PHONY),$?)          \

		$(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \

if_changed = $(if $(strip $(any-prereq) $(arg-check)),                       \

	@set -e;                                                             \

	$(echo-cmd) $(cmd_$(1));                                             \

	echo 'cmd_$@ := $(make-cmd)' > $(@D)/.$(@F).cmd)

	echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)



# execute the command and also postprocess generated .d dependencies

# file

if_changed_dep = $(if $(strip $(filter-out $(PHONY),$?)  \

		$(filter-out FORCE $(wildcard $^),$^)    \

	$(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),     \

if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ),                  \

	@set -e;                                                             \

	$(echo-cmd) $(cmd_$(1));                                             \

	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(@D)/.$(@F).tmp; \

	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\

	rm -f $(depfile);                                                    \

	mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd)

	mv -f $(dot-target).tmp $(dot-target).cmd)



# Usage: $(call if_changed_rule,foo)

# will check if $(cmd_foo) changed, or any of the prequisites changed,

# and if so will execute $(rule_foo)

if_changed_rule = $(if $(strip $(filter-out $(PHONY),$?)            \

			$(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\

if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ),                 \

	@set -e;                                                             \

	$(rule_$(1)))

scripts/Makefile.build

+3 −2
Original line number Diff line number Diff line
@@ -191,9 +191,10 @@ define rule_cc_o_c 
	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \

	$(call echo-cmd,cc_o_c) $(cmd_cc_o_c);				  \

	$(cmd_modversions)						  \

	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' > $(@D)/.$(@F).tmp;  \

	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' >    \

	                                              $(dot-target).tmp;  \

	rm -f $(depfile);						  \

	mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd

	mv -f $(dot-target).tmp $(dot-target).cmd

endef



# Built-in and composite module parts

usr/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -3,6 +3,8 @@ 
#



klibcdirs:;

PHONY += klibcdirs





# Generate builtin.o based on initramfs_data.o

obj-y := initramfs_data.o

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