2 # kbuild: Generic definitions
8 space := $(empty) $(empty)
11 # Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
12 dot-target = $(dir $@).$(notdir $@)
15 # The temporary file to save gcc -MD generated dependencies must not
17 depfile = $(subst $(comma),_,$(dot-target).d)
20 # filename of target with directory and extension stripped
21 basetarget = $(basename $(notdir $@))
24 # Escape single quote for use in echo statements
25 escsq = $(subst $(squote),'\$(squote)',$1)
28 # filechk is used to check if the content of a generated file is updated.
30 # define filechk_sample
33 # version.h : Makefile
34 # $(call filechk,sample)
35 # The rule defined shall write to stdout the content of the new file.
36 # The existing file will be compared with the new one.
37 # - If no file exist it is created
38 # - If the content differ the new file is used
39 # - If they are equal no change, and no timestamp update
40 # - stdin is piped in from the first prerequisite ($<) so one has
41 # to specify a valid file as first prerequisite (often the kbuild file)
46 $(filechk_$(1)) < $< > $@.tmp; \
47 if [ -r $@ ] && cmp -s $@ $@.tmp; then \
56 # gcc support functions
57 # See documentation in Documentation/kbuild/makefiles.txt
60 # Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,)
62 as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \
63 -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \
64 else echo "$(2)"; fi ;)
67 # Usage: cflags-y += $(call as-instr, instr, option1, option2)
69 as-instr = $(shell if echo -e "$(1)" | $(AS) >/dev/null 2>&1 -W -Z -o astest$$$$.out ; \
70 then echo "$(2)"; else echo "$(3)"; fi; \
74 # Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586)
76 cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
77 > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
80 # Usage: flag := $(call cc-option-yn, -march=winchip-c6)
81 cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
82 > /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
85 # Prefix align with either -falign or -malign
86 cc-option-align = $(subst -functions=0,,\
87 $(call cc-option,-falign-functions=0,-malign-functions=0))
90 # Usage gcc-ver := $(call cc-version, $(CC))
91 cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
94 # Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
95 cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \
99 # Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
100 ld-option = $(shell if $(CC) $(1) \
101 -nostdlib -o ldtest$$$$.out -xc /dev/null \
102 > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi; \
103 rm -f ldtest$$$$.out)
106 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
108 # $(Q)$(MAKE) $(build)=dir
109 build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
111 # Prefix -I with $(srctree) if it is not an absolute path
112 addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
113 # Find all -I options and call addtree
114 flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
116 # If quiet is set, only print short version of command
117 cmd = @$(echo-cmd) $(cmd_$(1))
119 # Add $(obj)/ for paths that is not absolute
120 objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
123 # if_changed - execute command if any prerequisite is newer than
124 # target, or command line has changed
125 # if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
126 # including used config symbols
127 # if_changed_rule - as if_changed but execute rule instead
128 # See Documentation/kbuild/makefiles.txt for more info
130 ifneq ($(KBUILD_NOCMDDEP),1)
131 # Check if both arguments has same arguments. Result in empty string if equal
132 # User may override this check using make KBUILD_NOCMDDEP=1
133 arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
134 $(filter-out $(cmd_$@), $(cmd_$(1))) )
137 # echo command. Short version is $(quiet) equals quiet, otherwise full command
138 echo-cmd = $(if $($(quiet)cmd_$(1)), \
139 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
141 # >'< substitution is for echo to work,
142 # >$< substitution to preserve $ when reloading .cmd file
143 # note: when using inline perl scripts [perl -e '...$$t=1;...']
144 # in $(cmd_xxx) double $$ your perl vars
145 make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
147 # Find any prerequisites that is newer than target or that does not exist.
148 # PHONY targets skipped in both cases.
149 any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
151 # Execute command if command has changed or prerequisitei(s) are updated
153 if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
155 $(echo-cmd) $(cmd_$(1)); \
156 echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
158 # execute the command and also postprocess generated .d dependencies
160 if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \
162 $(echo-cmd) $(cmd_$(1)); \
163 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
165 mv -f $(dot-target).tmp $(dot-target).cmd)
167 # Usage: $(call if_changed_rule,foo)
168 # will check if $(cmd_foo) changed, or any of the prequisites changed,
169 # and if so will execute $(rule_foo)
170 if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \
175 # why - tell why a a target got build
176 # enabled by make V=2
177 # Output (listed in the order they are checked):
178 # (1) - due to target is PHONY
179 # (2) - due to target missing
180 # (3) - due to: file1.h file2.h
181 # (4) - due to command line change
182 # (5) - due to missing .cmd file
183 # (6) - due to target not in $(targets)
184 # (1) PHONY targets are always build
185 # (2) No target, so we better build it
186 # (3) Prerequisite is newer than target
187 # (4) The command line stored in the file named dir/.target.cmd
188 # differed from actual command line. This happens when compiler
190 # (5) No dir/.target.cmd file (used to store command line)
191 # (6) No dir/.target.cmd file and target not listed in $(targets)
192 # This is a good hint that there is a bug in the kbuild file
193 ifeq ($(KBUILD_VERBOSE),2)
195 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \
196 $(if $(wildcard $@), \
197 $(if $(strip $(any-prereq)),- due to: $(any-prereq), \
199 $(if $(cmd_$@),- due to command line change, \
200 $(if $(filter $@, $(targets)), \
201 - due to missing .cmd file, \
202 - due to $(notdir $@) not in $$(targets) \
207 - due to target missing \
211 echo-why = $(call escsq, $(strip $(why)))