2 # kbuild: Generic definitions
8 space := $(empty) $(empty)
11 # The temporary file to save gcc -MD generated dependencies must not
13 depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
16 # filename of target with directory and extension stripped
17 basetarget = $(basename $(notdir $@))
20 # Escape single quote for use in echo statements
21 escsq = $(subst $(squote),'\$(squote)',$1)
24 # filechk is used to check if the content of a generated file is updated.
26 # define filechk_sample
29 # version.h : Makefile
30 # $(call filechk,sample)
31 # The rule defined shall write to stdout the content of the new file.
32 # The existing file will be compared with the new one.
33 # - If no file exist it is created
34 # - If the content differ the new file is used
35 # - If they are equal no change, and no timestamp update
36 # - stdin is piped in from the first prerequisite ($<) so one has
37 # to specify a valid file as first prerequisite (often the kbuild file)
42 $(filechk_$(1)) < $< > $@.tmp; \
43 if [ -r $@ ] && cmp -s $@ $@.tmp; then \
52 # gcc support functions
53 # See documentation in Documentation/kbuild/makefiles.txt
56 # Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,)
58 as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \
59 -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \
60 else echo "$(2)"; fi ;)
63 # Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586)
65 cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
66 > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
69 # Usage: flag := $(call cc-option-yn, -march=winchip-c6)
70 cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
71 > /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
74 # Prefix align with either -falign or -malign
75 cc-option-align = $(subst -functions=0,,\
76 $(call cc-option,-falign-functions=0,-malign-functions=0))
79 # Usage gcc-ver := $(call cc-version, $(CC))
80 cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
83 # Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
84 cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \
88 # Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
89 ld-option = $(shell if $(CC) $(1) \
90 -nostdlib -o ldtest$$$$.out -xc /dev/null \
91 > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi; \
95 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
97 # $(Q)$(MAKE) $(build)=dir
98 build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
100 # Prefix -I with $(srctree) if it is not an absolute path
101 addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
102 # Find all -I options and call addtree
103 flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
105 # If quiet is set, only print short version of command
106 cmd = @$(echo-cmd) $(cmd_$(1))
108 # Add $(obj)/ for paths that is not absolute
109 objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
112 # if_changed - execute command if any prerequisite is newer than
113 # target, or command line has changed
114 # if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
115 # including used config symbols
116 # if_changed_rule - as if_changed but execute rule instead
117 # See Documentation/kbuild/makefiles.txt for more info
119 ifneq ($(KBUILD_NOCMDDEP),1)
120 # Check if both arguments has same arguments. Result in empty string if equal
121 # User may override this check using make KBUILD_NOCMDDEP=1
122 arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )
125 # echo command. Short version is $(quiet) equals quiet, otherwise full command
126 echo-cmd = $(if $($(quiet)cmd_$(1)), \
127 echo ' $(call escsq,$($(quiet)cmd_$(1)))';)
129 make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
131 # function to only execute the passed command if necessary
132 # >'< substitution is for echo to work, >$< substitution to preserve $ when reloading .cmd file
133 # note: when using inline perl scripts [perl -e '...$$t=1;...'] in $(cmd_xxx) double $$ your perl vars
135 if_changed = $(if $(strip $(filter-out $(PHONY),$?) \
136 $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
138 $(echo-cmd) $(cmd_$(1)); \
139 echo 'cmd_$@ := $(make-cmd)' > $(@D)/.$(@F).cmd)
141 # execute the command and also postprocess generated .d dependencies
143 if_changed_dep = $(if $(strip $(filter-out $(PHONY),$?) \
144 $(filter-out FORCE $(wildcard $^),$^) \
145 $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
147 $(echo-cmd) $(cmd_$(1)); \
148 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(@D)/.$(@F).tmp; \
150 mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd)
152 # Usage: $(call if_changed_rule,foo)
153 # will check if $(cmd_foo) changed, or any of the prequisites changed,
154 # and if so will execute $(rule_foo)
155 if_changed_rule = $(if $(strip $(filter-out $(PHONY),$?) \
156 $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\