2 # kbuild: Generic definitions
7 space := $(empty) $(empty)
10 # The temporary file to save gcc -MD generated dependencies must not
12 depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
15 # filechk is used to check if the content of a generated file is updated.
17 # define filechk_sample
20 # version.h : Makefile
21 # $(call filechk,sample)
22 # The rule defined shall write to stdout the content of the new file.
23 # The existing file will be compared with the new one.
24 # - If no file exist it is created
25 # - If the content differ the new file is used
26 # - If they are equal no change, and no timestamp update
27 # - stdin is piped in from the first prerequisite ($<) so one has
28 # to specify a valid file as first prerequisite (often the kbuild file)
33 $(filechk_$(1)) < $< > $@.tmp; \
34 if [ -r $@ ] && cmp -s $@ $@.tmp; then \
43 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
45 # $(Q)$(MAKE) $(build)=dir
46 build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
48 # If quiet is set, only print short version of command
49 cmd = @$(if $($(quiet)cmd_$(1)),\
50 echo ' $(subst ','\'',$($(quiet)cmd_$(1)))' &&) $(cmd_$(1))
52 # Add $(obj)/ for paths that is not absolute
53 objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
56 # if_changed - execute command if any prerequisite is newer than
57 # target, or command line has changed
58 # if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
59 # including used config symbols
60 # if_changed_rule - as if_changed but execute rule instead
61 # See Documentation/kbuild/makefiles.txt for more info
63 ifneq ($(KBUILD_NOCMDDEP),1)
64 # Check if both arguments has same arguments. Result in empty string if equal
65 # User may override this check using make KBUILD_NOCMDDEP=1
66 arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )
69 # echo command. Short version is $(quiet) equals quiet, otherwise full command
70 echo-cmd = $(if $($(quiet)cmd_$(1)), \
71 echo ' $(subst ','\'',$($(quiet)cmd_$(1)))';)
73 # function to only execute the passed command if necessary
74 # >'< substitution is for echo to work, >$< substitution to preserve $ when reloading .cmd file
75 # note: when using inline perl scripts [perl -e '...$$t=1;...'] in $(cmd_xxx) double $$ your perl vars
77 if_changed = $(if $(strip $? $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
81 echo 'cmd_$@ := $(subst $$,$$$$,$(subst ','\'',$(cmd_$(1))))' > $(@D)/.$(@F).cmd)
83 # execute the command and also postprocess generated .d dependencies
85 if_changed_dep = $(if $(strip $? $(filter-out FORCE $(wildcard $^),$^)\
86 $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
90 scripts/basic/fixdep $(depfile) $@ '$(subst $$,$$$$,$(subst ','\'',$(cmd_$(1))))' > $(@D)/.$(@F).tmp; \
92 mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd)
94 # Usage: $(call if_changed_rule,foo)
95 # will check if $(cmd_foo) changed, or any of the prequisites changed,
96 # and if so will execute $(rule_foo)
97 if_changed_rule = $(if $(strip $? $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\