#### # kbuild: Generic definitions # Convinient variables comma := , empty := space := $(empty) $(empty) ### # The temporary file to save gcc -MD generated dependencies must not # contain a comma depfile = $(subst $(comma),_,$(@D)/.$(@F).d) ### # filechk is used to check if the content of a generated file is updated. # Sample usage: # define filechk_sample # echo $KERNELRELEASE # endef # version.h : Makefile # $(call filechk,sample) # The rule defined shall write to stdout the content of the new file. # The existing file will be compared with the new one. # - If no file exist it is created # - If the content differ the new file is used # - If they are equal no change, and no timestamp update # - stdin is piped in from the first prerequisite ($<) so one has # to specify a valid file as first prerequisite (often the kbuild file) define filechk $(Q)set -e; \ echo ' CHK $@'; \ mkdir -p $(dir $@); \ $(filechk_$(1)) < $< > $@.tmp; \ if [ -r $@ ] && cmp -s $@ $@.tmp; then \ rm -f $@.tmp; \ else \ echo ' UPD $@'; \ mv -f $@.tmp $@; \ fi endef ### # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= # Usage: # $(Q)$(MAKE) $(build)=dir build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj # If quiet is set, only print short version of command cmd = @$(if $($(quiet)cmd_$(1)),\ echo ' $(subst ','\'',$($(quiet)cmd_$(1)))' &&) $(cmd_$(1)) # Add $(obj)/ for paths that is not absolute objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o))) ### # if_changed - execute command if any prerequisite is newer than # target, or command line has changed # if_changed_dep - as if_changed, but uses fixdep to reveal dependencies # including used config symbols # if_changed_rule - as if_changed but execute rule instead # See Documentation/kbuild/makefiles.txt for more info ifneq ($(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)) ) endif # echo command. Short version is $(quiet) equals quiet, otherwise full command echo-cmd = $(if $($(quiet)cmd_$(1)), \ echo ' $(subst ','\'',$($(quiet)cmd_$(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 # if_changed = $(if $(strip $? $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \ @set -e; \ $(echo-cmd) \ $(cmd_$(1)); \ echo 'cmd_$@ := $(subst $$,$$$$,$(subst ','\'',$(cmd_$(1))))' > $(@D)/.$(@F).cmd) # execute the command and also postprocess generated .d dependencies # file if_changed_dep = $(if $(strip $? $(filter-out FORCE $(wildcard $^),$^)\ $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \ @set -e; \ $(echo-cmd) \ $(cmd_$(1)); \ scripts/basic/fixdep $(depfile) $@ '$(subst $$,$$$$,$(subst ','\'',$(cmd_$(1))))' > $(@D)/.$(@F).tmp; \ rm -f $(depfile); \ mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).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 $? $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\ @set -e; \ $(rule_$(1)))