1####
2# kbuild: Generic definitions
3
4# Convenient variables
5comma   := ,
6squote  := '
7empty   :=
8space   := $(empty) $(empty)
9
10###
11# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
12dot-target = $(dir $@).$(notdir $@)
13
14###
15# The temporary file to save gcc -MD generated dependencies must not
16# contain a comma
17depfile = $(subst $(comma),_,$(dot-target).d)
18
19###
20# filename of target with directory and extension stripped
21basetarget = $(basename $(notdir $@))
22
23###
24# filename of first prerequisite with directory and extension stripped
25baseprereq = $(basename $(notdir $<))
26
27###
28# Escape single quote for use in echo statements
29escsq = $(subst $(squote),'\$(squote)',$1)
30
31###
32# Easy method for doing a status message
33       kecho := :
34 quiet_kecho := echo
35silent_kecho := :
36kecho := $($(quiet)kecho)
37
38###
39# filechk is used to check if the content of a generated file is updated.
40# Sample usage:
41# define filechk_sample
42#	echo $KERNELRELEASE
43# endef
44# version.h : Makefile
45#	$(call filechk,sample)
46# The rule defined shall write to stdout the content of the new file.
47# The existing file will be compared with the new one.
48# - If no file exist it is created
49# - If the content differ the new file is used
50# - If they are equal no change, and no timestamp update
51# - stdin is piped in from the first prerequisite ($<) so one has
52#   to specify a valid file as first prerequisite (often the kbuild file)
53define filechk
54	$(Q)set -e;				\
55	$(kecho) '  CHK     $@';		\
56	mkdir -p $(dir $@);			\
57	$(filechk_$(1)) < $< > $@.tmp;		\
58	if [ -r $@ ] && cmp -s $@ $@.tmp; then	\
59		rm -f $@.tmp;			\
60	else					\
61		$(kecho) '  UPD     $@';	\
62		mv -f $@.tmp $@;		\
63	fi
64endef
65
66######
67# gcc support functions
68# See documentation in Documentation/kbuild/makefiles.txt
69
70# cc-cross-prefix
71# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
72# Return first prefix where a prefix$(CC) is found in PATH.
73# If no $(CC) found in PATH with listed prefixes return nothing
74cc-cross-prefix =  \
75	$(word 1, $(foreach c,$(1),                                   \
76		$(shell set -e;                                       \
77		if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \
78			echo $(c);                                    \
79		fi)))
80
81# output directory for tests below
82TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
83
84# try-run
85# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
86# Exit code chooses option. "$$TMP" is can be used as temporary file and
87# is automatically cleaned up.
88try-run = $(shell set -e;		\
89	TMP="$(TMPOUT).$$$$.tmp";	\
90	TMPO="$(TMPOUT).$$$$.o";	\
91	if ($(1)) >/dev/null 2>&1;	\
92	then echo "$(2)";		\
93	else echo "$(3)";		\
94	fi;				\
95	rm -f "$$TMP" "$$TMPO")
96
97# as-option
98# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
99
100as-option = $(call try-run,\
101	$(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))
102
103# as-instr
104# Usage: cflags-y += $(call as-instr,instr,option1,option2)
105
106as-instr = $(call try-run,\
107	printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
108
109# cc-option
110# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
111
112cc-option = $(call try-run,\
113	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
114
115# cc-option-yn
116# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
117cc-option-yn = $(call try-run,\
118	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
119
120# cc-option-align
121# Prefix align with either -falign or -malign
122cc-option-align = $(subst -functions=0,,\
123	$(call cc-option,-falign-functions=0,-malign-functions=0))
124
125# cc-disable-warning
126# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
127cc-disable-warning = $(call try-run,\
128	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
129
130# cc-version
131# Usage gcc-ver := $(call cc-version)
132cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
133
134# cc-fullversion
135# Usage gcc-ver := $(call cc-fullversion)
136cc-fullversion = $(shell $(CONFIG_SHELL) \
137	$(srctree)/scripts/gcc-version.sh -p $(CC))
138
139# cc-ifversion
140# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
141cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
142
143# cc-ldoption
144# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
145cc-ldoption = $(call try-run,\
146	$(CC) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))
147
148# ld-option
149# Usage: LDFLAGS += $(call ld-option, -X)
150ld-option = $(call try-run,\
151	$(CC) /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
152
153# ar-option
154# Usage: KBUILD_ARFLAGS := $(call ar-option,D)
155# Important: no spaces around options
156ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2))
157
158######
159
160###
161# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
162# Usage:
163# $(Q)$(MAKE) $(build)=dir
164build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
165
166###
167# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj=
168# Usage:
169# $(Q)$(MAKE) $(modbuiltin)=dir
170modbuiltin := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.modbuiltin obj
171
172# Prefix -I with $(srctree) if it is not an absolute path.
173# skip if -I has no parameter
174addtree = $(if $(patsubst -I%,%,$(1)), \
175$(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1))
176
177# Find all -I options and call addtree
178flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
179
180# echo command.
181# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
182echo-cmd = $(if $($(quiet)cmd_$(1)),\
183	echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
184
185# printing commands
186cmd = @$(echo-cmd) $(cmd_$(1))
187
188# Add $(obj)/ for paths that are not absolute
189objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
190
191###
192# if_changed      - execute command if any prerequisite is newer than
193#                   target, or command line has changed
194# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
195#                   including used config symbols
196# if_changed_rule - as if_changed but execute rule instead
197# See Documentation/kbuild/makefiles.txt for more info
198
199ifneq ($(KBUILD_NOCMDDEP),1)
200# Check if both arguments has same arguments. Result is empty string if equal.
201# User may override this check using make KBUILD_NOCMDDEP=1
202arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
203                    $(filter-out $(cmd_$@),   $(cmd_$(1))) )
204else
205arg-check = $(if $(strip $(cmd_$@)),,1)
206endif
207
208# >'< substitution is for echo to work,
209# >$< substitution to preserve $ when reloading .cmd file
210# note: when using inline perl scripts [perl -e '...$$t=1;...']
211# in $(cmd_xxx) double $$ your perl vars
212make-cmd = $(subst \\,\\\\,$(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1))))))
213
214# Find any prerequisites that is newer than target or that does not exist.
215# PHONY targets skipped in both cases.
216any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
217
218# Execute command if command has changed or prerequisite(s) are updated.
219#
220if_changed = $(if $(strip $(any-prereq) $(arg-check)),                       \
221	@set -e;                                                             \
222	$(echo-cmd) $(cmd_$(1));                                             \
223	echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
224
225# Execute the command and also postprocess generated .d dependencies file.
226if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ),                  \
227	@set -e;                                                             \
228	$(echo-cmd) $(cmd_$(1));                                             \
229	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
230	rm -f $(depfile);                                                    \
231	mv -f $(dot-target).tmp $(dot-target).cmd)
232
233# Usage: $(call if_changed_rule,foo)
234# Will check if $(cmd_foo) or any of the prerequisites changed,
235# and if so will execute $(rule_foo).
236if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ),                 \
237	@set -e;                                                             \
238	$(rule_$(1)))
239
240###
241# why - tell why a a target got build
242#       enabled by make V=2
243#       Output (listed in the order they are checked):
244#          (1) - due to target is PHONY
245#          (2) - due to target missing
246#          (3) - due to: file1.h file2.h
247#          (4) - due to command line change
248#          (5) - due to missing .cmd file
249#          (6) - due to target not in $(targets)
250# (1) PHONY targets are always build
251# (2) No target, so we better build it
252# (3) Prerequisite is newer than target
253# (4) The command line stored in the file named dir/.target.cmd
254#     differed from actual command line. This happens when compiler
255#     options changes
256# (5) No dir/.target.cmd file (used to store command line)
257# (6) No dir/.target.cmd file and target not listed in $(targets)
258#     This is a good hint that there is a bug in the kbuild file
259ifeq ($(KBUILD_VERBOSE),2)
260why =                                                                        \
261    $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
262        $(if $(wildcard $@),                                                 \
263            $(if $(strip $(any-prereq)),- due to: $(any-prereq),             \
264                $(if $(arg-check),                                           \
265                    $(if $(cmd_$@),- due to command line change,             \
266                        $(if $(filter $@, $(targets)),                       \
267                            - due to missing .cmd file,                      \
268                            - due to $(notdir $@) not in $$(targets)         \
269                         )                                                   \
270                     )                                                       \
271                 )                                                           \
272             ),                                                              \
273             - due to target missing                                         \
274         )                                                                   \
275     )
276
277echo-why = $(call escsq, $(strip $(why)))
278endif
279