#### # kbuild: Generic definitions # Convinient variables comma := , 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 $(comma),_,$(dot-target).d) ### # filename of target with directory and extension stripped basetarget = $(basename $(notdir $@)) ### # Escape single quote for use in echo statements escsq = $(subst $(squote),'\$(squote)',$1) ### # 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 ###### # gcc support functions # See documentation in Documentation/kbuild/makefiles.txt # as-option # Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,) as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \ -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \ else echo "$(2)"; fi ;) # as-instr # Usage: cflags-y += $(call as-instr, instr, option1, option2) as-instr = $(shell if echo -e "$(1)" | $(AS) >/dev/null 2>&1 -W -Z -o astest$$$$.out ; \ then echo "$(2)"; else echo "$(3)"; fi; \ rm -f astest$$$$.out) # cc-option # Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586) cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \ > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;) # cc-option-yn # Usage: flag := $(call cc-option-yn, -march=winchip-c6) cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \ > /dev/null 2>&1; then echo "y"; else echo "n"; fi;) # cc-option-align # Prefix align with either -falign or -malign cc-option-align = $(subst -functions=0,,\ $(call cc-option,-falign-functions=0,-malign-functions=0)) # cc-version # Usage gcc-ver := $(call cc-version, $(CC)) cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC)) # cc-ifversion # Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1) cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \ echo $(3); fi;) # ld-option # Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both) ld-option = $(shell if $(CC) $(1) \ -nostdlib -o ldtest$$$$.out -xc /dev/null \ > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi; \ rm -f ldtest$$$$.out) ### # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= # Usage: # $(Q)$(MAKE) $(build)=dir build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj # Prefix -I with $(srctree) if it is not an absolute path addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1) # Find all -I options and call addtree flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o))) # If quiet is set, only print short version of command cmd = @$(echo-cmd) $(cmd_$(1)) # Add $(obj)/ for paths that is not absolute objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o))) ### # if_changed - execute command if any prerequisite is newer than # target, or command line has changed # if_changed_dep - as if_changed, but uses fixdep to reveal dependencies # including used config symbols # if_changed_rule - as if_changed but execute rule instead # See Documentation/kbuild/makefiles.txt for more info ifneq ($(KBUILD_NOCMDDEP),1) # Check if both arguments has same arguments. Result in empty string if equal # User may override this check using make KBUILD_NOCMDDEP=1 arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \ $(filter-out $(cmd_$@), $(cmd_$(1))) ) endif # echo command. Short version is $(quiet) equals quiet, otherwise full command echo-cmd = $(if $($(quiet)cmd_$(1)), \ echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';) # >'< substitution is for echo to work, # >$< substitution to preserve $ when reloading .cmd file # note: when using inline perl scripts [perl -e '...$$t=1;...'] # in $(cmd_xxx) double $$ your perl vars make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1))))) # 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 $(any-prereq) $(arg-check)), \ @set -e; \ $(echo-cmd) $(cmd_$(1)); \ echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd) # execute the command and also postprocess generated .d dependencies # file if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \ @set -e; \ $(echo-cmd) $(cmd_$(1)); \ scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\ rm -f $(depfile); \ 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 $(any-prereq) $(arg-check) ), \ @set -e; \ $(rule_$(1))) ### # why - tell why a a target got build # enabled by make V=2 # Output (listed in the order they are checked): # (1) - due to target is PHONY # (2) - due to target missing # (3) - due to: file1.h file2.h # (4) - due to command line change # (5) - due to missing .cmd file # (6) - due to target not in $(targets) # (1) PHONY targets are always build # (2) No target, so we better build it # (3) Prerequisite is newer than target # (4) The command line stored in the file named dir/.target.cmd # differed from actual command line. This happens when compiler # options changes # (5) No dir/.target.cmd file (used to store command line) # (6) No dir/.target.cmd file and target not listed in $(targets) # This is a good hint that there is a bug in the kbuild file ifeq ($(KBUILD_VERBOSE),2) why = \ $(if $(filter $@, $(PHONY)),- due to target is PHONY, \ $(if $(wildcard $@), \ $(if $(strip $(any-prereq)),- due to: $(any-prereq), \ $(if $(arg-check), \ $(if $(cmd_$@),- due to command line change, \ $(if $(filter $@, $(targets)), \ - due to missing .cmd file, \ - due to $(notdir $@) not in $$(targets) \ ) \ ) \ ) \ ), \ - due to target missing \ ) \ ) echo-why = $(call escsq, $(strip $(why))) endif