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# Escape single quote for use in echo statements
25escsq = $(subst $(squote),'\$(squote)',$1)
26
27###
28# Easy method for doing a status message
29       kecho := :
30 quiet_kecho := echo
31silent_kecho := :
32kecho := $($(quiet)kecho)
33
34###
35# filechk is used to check if the content of a generated file is updated.
36# Sample usage:
37# define filechk_sample
38#	echo $KERNELRELEASE
39# endef
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)
49define filechk
50	$(Q)set -e;				\
51	$(kecho) '  CHK     $@';		\
52	mkdir -p $(dir $@);			\
53	$(filechk_$(1)) < $< > $@.tmp;		\
54	if [ -r $@ ] && cmp -s $@ $@.tmp; then	\
55		rm -f $@.tmp;			\
56	else					\
57		$(kecho) '  UPD     $@';	\
58		mv -f $@.tmp $@;		\
59	fi
60endef
61
62######
63# gcc support functions
64# See documentation in Documentation/kbuild/makefiles.txt
65
66# cc-cross-prefix
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
70cc-cross-prefix =  \
71	$(word 1, $(foreach c,$(1),                                   \
72		$(shell set -e;                                       \
73		if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \
74			echo $(c);                                    \
75		fi)))
76
77# output directory for tests below
78TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
79
80# try-run
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.
84try-run = $(shell set -e;		\
85	TMP="$(TMPOUT).$$$$.tmp";	\
86	TMPO="$(TMPOUT).$$$$.o";	\
87	if ($(1)) >/dev/null 2>&1;	\
88	then echo "$(2)";		\
89	else echo "$(3)";		\
90	fi;				\
91	rm -f "$$TMP" "$$TMPO")
92
93# as-option
94# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
95
96as-option = $(call try-run,\
97	$(CC) $(KBUILD_CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2))
98
99# as-instr
100# Usage: cflags-y += $(call as-instr,instr,option1,option2)
101
102as-instr = $(call try-run,\
103	/bin/echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
104
105# cc-option
106# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
107
108cc-option = $(call try-run,\
109	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",$(1),$(2))
110
111# cc-option-yn
112# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
113cc-option-yn = $(call try-run,\
114	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",y,n)
115
116# cc-option-align
117# Prefix align with either -falign or -malign
118cc-option-align = $(subst -functions=0,,\
119	$(call cc-option,-falign-functions=0,-malign-functions=0))
120
121# cc-version
122# Usage gcc-ver := $(call cc-version)
123cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
124
125# cc-fullversion
126# Usage gcc-ver := $(call cc-fullversion)
127cc-fullversion = $(shell $(CONFIG_SHELL) \
128	$(srctree)/scripts/gcc-version.sh -p $(CC))
129
130# cc-ifversion
131# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
132cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
133
134# cc-ldoption
135# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
136cc-ldoption = $(call try-run,\
137	$(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
138
139# ld-option
140# Usage: LDFLAGS += $(call ld-option, -X)
141ld-option = $(call try-run,\
142	$(CC) /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
143
144######
145
146###
147# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
148# Usage:
149# $(Q)$(MAKE) $(build)=dir
150build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
151
152###
153# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj=
154# Usage:
155# $(Q)$(MAKE) $(modbuiltin)=dir
156modbuiltin := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.modbuiltin obj
157
158# Prefix -I with $(srctree) if it is not an absolute path.
159# skip if -I has no parameter
160addtree = $(if $(patsubst -I%,%,$(1)), \
161$(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1))
162
163# Find all -I options and call addtree
164flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
165
166# echo command.
167# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
168echo-cmd = $(if $($(quiet)cmd_$(1)),\
169	echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
170
171# printing commands
172cmd = @$(echo-cmd) $(cmd_$(1))
173
174# Add $(obj)/ for paths that are not absolute
175objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
176
177###
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
184
185ifneq ($(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
188arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
189                    $(filter-out $(cmd_$@),   $(cmd_$(1))) )
190endif
191
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 $$ your perl vars
196make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
197
198# Find any prerequisites that is newer than target or that does not exist.
199# PHONY targets skipped in both cases.
200any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
201
202# Execute command if command has changed or prerequisite(s) are updated.
203#
204if_changed = $(if $(strip $(any-prereq) $(arg-check)),                       \
205	@set -e;                                                             \
206	$(echo-cmd) $(cmd_$(1));                                             \
207	echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
208
209# Execute the command and also postprocess generated .d dependencies file.
210if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ),                  \
211	@set -e;                                                             \
212	$(echo-cmd) $(cmd_$(1));                                             \
213	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
214	rm -f $(depfile);                                                    \
215	mv -f $(dot-target).tmp $(dot-target).cmd)
216
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).
220if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ),                 \
221	@set -e;                                                             \
222	$(rule_$(1)))
223
224###
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
239#     options changes
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
243ifeq ($(KBUILD_VERBOSE),2)
244why =                                                                        \
245    $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
246        $(if $(wildcard $@),                                                 \
247            $(if $(strip $(any-prereq)),- due to: $(any-prereq),             \
248                $(if $(arg-check),                                           \
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)         \
253                         )                                                   \
254                     )                                                       \
255                 )                                                           \
256             ),                                                              \
257             - due to target missing                                         \
258         )                                                                   \
259     )
260
261echo-why = $(call escsq, $(strip $(why)))
262endif
263