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)
43 quiet_chk_filechk = echo ' CHK $@'
44 silent_chk_filechk = :
46 quiet_upd_filechk = echo ' UPD $@'
47 silent_upd_filechk = :
51 $($(quiet)chk_filechk); \
53 $(filechk_$(1)) < $< > $@.tmp; \
54 if [ -r $@ ] && cmp -s $@ $@.tmp; then \
57 $($(quiet)upd_filechk); \
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).$$$$.tmp"; \
86 if ($(1)) >/dev/null 2>&1; \
93 # Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
95 as-option = $(call try-run,\
96 $(CC) $(KBUILD_CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2))
99 # Usage: cflags-y += $(call as-instr,instr,option1,option2)
101 as-instr = $(call try-run,\
102 echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
105 # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
107 cc-option = $(call try-run,\
108 $(CC) $(KBUILD_CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",$(1),$(2))
111 # Usage: flag := $(call cc-option-yn,-march=winchip-c6)
112 cc-option-yn = $(call try-run,\
113 $(CC) $(KBUILD_CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",y,n)
116 # Prefix align with either -falign or -malign
117 cc-option-align = $(subst -functions=0,,\
118 $(call cc-option,-falign-functions=0,-malign-functions=0))
121 # Usage gcc-ver := $(call cc-version)
122 cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
125 # Usage gcc-ver := $(call cc-fullversion)
126 cc-fullversion = $(shell $(CONFIG_SHELL) \
127 $(srctree)/scripts/gcc-version.sh -p $(CC))
130 # Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
131 cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
134 # Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
135 ld-option = $(call try-run,\
136 $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
141 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
143 # $(Q)$(MAKE) $(build)=dir
144 build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
146 # Prefix -I with $(srctree) if it is not an absolute path.
147 addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
149 # Find all -I options and call addtree
150 flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
153 # Short version is used, if $(quiet) equals `quiet_', otherwise full one.
154 echo-cmd = $(if $($(quiet)cmd_$(1)),\
155 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
158 cmd = @$(echo-cmd) $(cmd_$(1))
160 # Add $(obj)/ for paths that are not absolute
161 objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
164 # if_changed - execute command if any prerequisite is newer than
165 # target, or command line has changed
166 # if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
167 # including used config symbols
168 # if_changed_rule - as if_changed but execute rule instead
169 # See Documentation/kbuild/makefiles.txt for more info
171 ifneq ($(KBUILD_NOCMDDEP),1)
172 # Check if both arguments has same arguments. Result is empty string if equal.
173 # User may override this check using make KBUILD_NOCMDDEP=1
174 arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
175 $(filter-out $(cmd_$@), $(cmd_$(1))) )
178 # >'< substitution is for echo to work,
179 # >$< substitution to preserve $ when reloading .cmd file
180 # note: when using inline perl scripts [perl -e '...$$t=1;...']
181 # in $(cmd_xxx) double $$ your perl vars
182 make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
184 # Find any prerequisites that is newer than target or that does not exist.
185 # PHONY targets skipped in both cases.
186 any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
188 # Execute command if command has changed or prerequisite(s) are updated.
190 if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
192 $(echo-cmd) $(cmd_$(1)); \
193 echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
195 # Execute the command and also postprocess generated .d dependencies file.
196 if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \
198 $(echo-cmd) $(cmd_$(1)); \
199 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
201 mv -f $(dot-target).tmp $(dot-target).cmd)
203 # Usage: $(call if_changed_rule,foo)
204 # Will check if $(cmd_foo) or any of the prerequisites changed,
205 # and if so will execute $(rule_foo).
206 if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \
211 # why - tell why a a target got build
212 # enabled by make V=2
213 # Output (listed in the order they are checked):
214 # (1) - due to target is PHONY
215 # (2) - due to target missing
216 # (3) - due to: file1.h file2.h
217 # (4) - due to command line change
218 # (5) - due to missing .cmd file
219 # (6) - due to target not in $(targets)
220 # (1) PHONY targets are always build
221 # (2) No target, so we better build it
222 # (3) Prerequisite is newer than target
223 # (4) The command line stored in the file named dir/.target.cmd
224 # differed from actual command line. This happens when compiler
226 # (5) No dir/.target.cmd file (used to store command line)
227 # (6) No dir/.target.cmd file and target not listed in $(targets)
228 # This is a good hint that there is a bug in the kbuild file
229 ifeq ($(KBUILD_VERBOSE),2)
231 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \
232 $(if $(wildcard $@), \
233 $(if $(strip $(any-prereq)),- due to: $(any-prereq), \
235 $(if $(cmd_$@),- due to command line change, \
236 $(if $(filter $@, $(targets)), \
237 - due to missing .cmd file, \
238 - due to $(notdir $@) not in $$(targets) \
243 - due to target missing \
247 echo-why = $(call escsq, $(strip $(why)))