Root/scripts/Kbuild.include

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 "$$TMP",y,n)
115
116# cc-option-align
117# Prefix align with either -falign or -malign
118cc-option-align = $(subst -functions=0,,\
119    $(call cc-option,-falign-functions=0,-malign-functions=0))
120
121# cc-disable-warning
122# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
123cc-disable-warning = $(call try-run,\
124    $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -xc /dev/null -o "$$TMP",-Wno-$(strip $(1)))
125
126# cc-version
127# Usage gcc-ver := $(call cc-version)
128cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
129
130# cc-fullversion
131# Usage gcc-ver := $(call cc-fullversion)
132cc-fullversion = $(shell $(CONFIG_SHELL) \
133    $(srctree)/scripts/gcc-version.sh -p $(CC))
134
135# cc-ifversion
136# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
137cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
138
139# cc-ldoption
140# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
141cc-ldoption = $(call try-run,\
142    $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
143
144# ld-option
145# Usage: LDFLAGS += $(call ld-option, -X)
146ld-option = $(call try-run,\
147    $(CC) /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
148
149# ar-option
150# Usage: KBUILD_ARFLAGS := $(call ar-option,D)
151# Important: no spaces around options
152ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2))
153
154######
155
156###
157# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
158# Usage:
159# $(Q)$(MAKE) $(build)=dir
160build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
161
162###
163# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj=
164# Usage:
165# $(Q)$(MAKE) $(modbuiltin)=dir
166modbuiltin := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.modbuiltin obj
167
168# Prefix -I with $(srctree) if it is not an absolute path.
169# skip if -I has no parameter
170addtree = $(if $(patsubst -I%,%,$(1)), \
171$(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1))
172
173# Find all -I options and call addtree
174flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
175
176# echo command.
177# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
178echo-cmd = $(if $($(quiet)cmd_$(1)),\
179    echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
180
181# printing commands
182cmd = @$(echo-cmd) $(cmd_$(1))
183
184# Add $(obj)/ for paths that are not absolute
185objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
186
187###
188# if_changed - execute command if any prerequisite is newer than
189# target, or command line has changed
190# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
191# including used config symbols
192# if_changed_rule - as if_changed but execute rule instead
193# See Documentation/kbuild/makefiles.txt for more info
194
195ifneq ($(KBUILD_NOCMDDEP),1)
196# Check if both arguments has same arguments. Result is empty string if equal.
197# User may override this check using make KBUILD_NOCMDDEP=1
198arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
199                    $(filter-out $(cmd_$@), $(cmd_$(1))) )
200else
201arg-check = $(if $(strip $(cmd_$@)),,1)
202endif
203
204# >'< substitution is for echo to work,
205# >$< substitution to preserve $ when reloading .cmd file
206# note: when using inline perl scripts [perl -e '...$$t=1;...']
207# in $(cmd_xxx) double $$ your perl vars
208make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
209
210# Find any prerequisites that is newer than target or that does not exist.
211# PHONY targets skipped in both cases.
212any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
213
214# Execute command if command has changed or prerequisite(s) are updated.
215#
216if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
217    @set -e; \
218    $(echo-cmd) $(cmd_$(1)); \
219    echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
220
221# Execute the command and also postprocess generated .d dependencies file.
222if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \
223    @set -e; \
224    $(echo-cmd) $(cmd_$(1)); \
225    scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
226    rm -f $(depfile); \
227    mv -f $(dot-target).tmp $(dot-target).cmd)
228
229# Usage: $(call if_changed_rule,foo)
230# Will check if $(cmd_foo) or any of the prerequisites changed,
231# and if so will execute $(rule_foo).
232if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \
233    @set -e; \
234    $(rule_$(1)))
235
236###
237# why - tell why a a target got build
238# enabled by make V=2
239# Output (listed in the order they are checked):
240# (1) - due to target is PHONY
241# (2) - due to target missing
242# (3) - due to: file1.h file2.h
243# (4) - due to command line change
244# (5) - due to missing .cmd file
245# (6) - due to target not in $(targets)
246# (1) PHONY targets are always build
247# (2) No target, so we better build it
248# (3) Prerequisite is newer than target
249# (4) The command line stored in the file named dir/.target.cmd
250# differed from actual command line. This happens when compiler
251# options changes
252# (5) No dir/.target.cmd file (used to store command line)
253# (6) No dir/.target.cmd file and target not listed in $(targets)
254# This is a good hint that there is a bug in the kbuild file
255ifeq ($(KBUILD_VERBOSE),2)
256why = \
257    $(if $(filter $@, $(PHONY)),- due to target is PHONY, \
258        $(if $(wildcard $@), \
259            $(if $(strip $(any-prereq)),- due to: $(any-prereq), \
260                $(if $(arg-check), \
261                    $(if $(cmd_$@),- due to command line change, \
262                        $(if $(filter $@, $(targets)), \
263                            - due to missing .cmd file, \
264                            - due to $(notdir $@) not in $$(targets) \
265                         ) \
266                     ) \
267                 ) \
268             ), \
269             - due to target missing \
270         ) \
271     )
272
273echo-why = $(call escsq, $(strip $(why)))
274endif
275

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