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 # Easy method for doing a status message
32 kecho := $($(quiet)kecho)
35 # filechk is used to check if the content of a generated file is updated.
37 # define filechk_sample
40 # version.h : Makefile
41 # $(call filechk,sample)
42 # The rule defined shall write to stdout the content of the new file.
43 # The existing file will be compared with the new one.
44 # - If no file exist it is created
45 # - If the content differ the new file is used
46 # - If they are equal no change, and no timestamp update
47 # - stdin is piped in from the first prerequisite ($<) so one has
48 # to specify a valid file as first prerequisite (often the kbuild file)
53 $(filechk_$(1)) < $< > $@.tmp; \
54 if [ -r $@ ] && cmp -s $@ $@.tmp; then \
63 # gcc support functions
64 # See documentation in Documentation/kbuild/makefiles.txt
67 # Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
68 # Return first prefix where a prefix$(CC) is found in PATH.
69 # If no $(CC) found in PATH with listed prefixes return nothing
71 $(word 1, $(foreach c,$(1), \
73 if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \
77 # output directory for tests below
78 TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
81 # Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
82 # Exit code chooses option. "$$TMP" is can be used as temporary file and
83 # is automatically cleaned up.
84 try-run = $(shell set -e; \
85 TMP="$(TMPOUT).$$$$.tmp"; \
86 TMPO="$(TMPOUT).$$$$.o"; \
87 if ($(1)) >/dev/null 2>&1; \
91 rm -f "$$TMP" "$$TMPO")
94 # Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
96 as-option = $(call try-run,\
97 $(CC) $(KBUILD_CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2))
100 # Usage: cflags-y += $(call as-instr,instr,option1,option2)
102 as-instr = $(call try-run,\
103 /bin/echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
106 # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
108 cc-option = $(call try-run,\
109 $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",$(1),$(2))
112 # Usage: flag := $(call cc-option-yn,-march=winchip-c6)
113 cc-option-yn = $(call try-run,\
114 $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",y,n)
117 # Prefix align with either -falign or -malign
118 cc-option-align = $(subst -functions=0,,\
119 $(call cc-option,-falign-functions=0,-malign-functions=0))
122 # Usage gcc-ver := $(call cc-version)
123 cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
126 # Usage gcc-ver := $(call cc-fullversion)
127 cc-fullversion = $(shell $(CONFIG_SHELL) \
128 $(srctree)/scripts/gcc-version.sh -p $(CC))
131 # Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
132 cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
135 # Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
136 cc-ldoption = $(call try-run,\
137 $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
140 # Usage: LDFLAGS += $(call ld-option, -X)
141 ld-option = $(call try-run,\
142 $(CC) /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
147 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
149 # $(Q)$(MAKE) $(build)=dir
150 build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
153 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj=
155 # $(Q)$(MAKE) $(modbuiltin)=dir
156 modbuiltin := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.modbuiltin obj
158 # Prefix -I with $(srctree) if it is not an absolute path.
159 # skip if -I has no parameter
160 addtree = $(if $(patsubst -I%,%,$(1)), \
161 $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1))
163 # Find all -I options and call addtree
164 flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
167 # Short version is used, if $(quiet) equals `quiet_', otherwise full one.
168 echo-cmd = $(if $($(quiet)cmd_$(1)),\
169 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
172 cmd = @$(echo-cmd) $(cmd_$(1))
174 # Add $(obj)/ for paths that are not absolute
175 objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
178 # if_changed - execute command if any prerequisite is newer than
179 # target, or command line has changed
180 # if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
181 # including used config symbols
182 # if_changed_rule - as if_changed but execute rule instead
183 # See Documentation/kbuild/makefiles.txt for more info
185 ifneq ($(KBUILD_NOCMDDEP),1)
186 # Check if both arguments has same arguments. Result is empty string if equal.
187 # User may override this check using make KBUILD_NOCMDDEP=1
188 arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
189 $(filter-out $(cmd_$@), $(cmd_$(1))) )
192 # >'< substitution is for echo to work,
193 # >$< substitution to preserve $ when reloading .cmd file
194 # note: when using inline perl scripts [perl -e '...$$t=1;...']
195 # in $(cmd_xxx) double $$ your perl vars
196 make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
198 # Find any prerequisites that is newer than target or that does not exist.
199 # PHONY targets skipped in both cases.
200 any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
202 # Execute command if command has changed or prerequisite(s) are updated.
204 if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
206 $(echo-cmd) $(cmd_$(1)); \
207 echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
209 # Execute the command and also postprocess generated .d dependencies file.
210 if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \
212 $(echo-cmd) $(cmd_$(1)); \
213 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
215 mv -f $(dot-target).tmp $(dot-target).cmd)
217 # Usage: $(call if_changed_rule,foo)
218 # Will check if $(cmd_foo) or any of the prerequisites changed,
219 # and if so will execute $(rule_foo).
220 if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \
225 # why - tell why a a target got build
226 # enabled by make V=2
227 # Output (listed in the order they are checked):
228 # (1) - due to target is PHONY
229 # (2) - due to target missing
230 # (3) - due to: file1.h file2.h
231 # (4) - due to command line change
232 # (5) - due to missing .cmd file
233 # (6) - due to target not in $(targets)
234 # (1) PHONY targets are always build
235 # (2) No target, so we better build it
236 # (3) Prerequisite is newer than target
237 # (4) The command line stored in the file named dir/.target.cmd
238 # differed from actual command line. This happens when compiler
240 # (5) No dir/.target.cmd file (used to store command line)
241 # (6) No dir/.target.cmd file and target not listed in $(targets)
242 # This is a good hint that there is a bug in the kbuild file
243 ifeq ($(KBUILD_VERBOSE),2)
245 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \
246 $(if $(wildcard $@), \
247 $(if $(strip $(any-prereq)),- due to: $(any-prereq), \
249 $(if $(cmd_$@),- due to command line change, \
250 $(if $(filter $@, $(targets)), \
251 - due to missing .cmd file, \
252 - due to $(notdir $@) not in $$(targets) \
257 - due to target missing \
261 echo-why = $(call escsq, $(strip $(why)))