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kbuild: fix up CFLAGS usage
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1####
2# kbuild: Generic definitions
3
beda9f3a 4# Convenient variables
8ec4b4ff 5comma := ,
d51bfb78 6squote := '
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7empty :=
8space := $(empty) $(empty)
9
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10###
11# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
12dot-target = $(dir $@).$(notdir $@)
13
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14###
15# The temporary file to save gcc -MD generated dependencies must not
16# contain a comma
48f1f058 17depfile = $(subst $(comma),_,$(dot-target).d)
8ec4b4ff 18
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19###
20# filename of target with directory and extension stripped
21basetarget = $(basename $(notdir $@))
22
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23###
24# Escape single quote for use in echo statements
25escsq = $(subst $(squote),'\$(squote)',$1)
26
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27###
28# filechk is used to check if the content of a generated file is updated.
29# Sample usage:
30# define filechk_sample
31# echo $KERNELRELEASE
32# endef
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)
42define filechk
43 $(Q)set -e; \
44 echo ' CHK $@'; \
45 mkdir -p $(dir $@); \
46 $(filechk_$(1)) < $< > $@.tmp; \
47 if [ -r $@ ] && cmp -s $@ $@.tmp; then \
48 rm -f $@.tmp; \
49 else \
50 echo ' UPD $@'; \
51 mv -f $@.tmp $@; \
52 fi
53endef
54
20a468b5 55######
9d6e7a70 56# gcc support functions
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57# See documentation in Documentation/kbuild/makefiles.txt
58
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59# output directory for tests below
60TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
61
62# try-run
63# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
64# Exit code chooses option. "$$TMP" is can be used as temporary file and
65# is automatically cleaned up.
66try-run = $(shell set -e; \
67 TMP="$(TMPOUT).$$$$.tmp"; \
68 if ($(1)) >/dev/null 2>&1; \
69 then echo "$(2)"; \
70 else echo "$(3)"; \
71 fi; \
72 rm -f "$$TMP")
347a00fb 73
20a468b5 74# as-option
bff288c1 75# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
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76
77as-option = $(call try-run,\
78 $(CC) $(CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2))
20a468b5 79
e2414910 80# as-instr
bff288c1 81# Usage: cflags-y += $(call as-instr,instr,option1,option2)
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82
83as-instr = $(call try-run,\
84 echo -e "$(1)" | $(CC) $(AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
e2414910 85
20a468b5 86# cc-option
bff288c1 87# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
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88
89cc-option = $(call try-run,\
90 $(CC) $(CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",$(1),$(2))
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91
92# cc-option-yn
bff288c1 93# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
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94cc-option-yn = $(call try-run,\
95 $(CC) $(CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",y,n)
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96
97# cc-option-align
98# Prefix align with either -falign or -malign
99cc-option-align = $(subst -functions=0,,\
beda9f3a 100 $(call cc-option,-falign-functions=0,-malign-functions=0))
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101
102# cc-version
0ab2a272 103# Usage gcc-ver := $(call cc-version)
8eb3afe0 104cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
20a468b5 105
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106# cc-fullversion
107# Usage gcc-ver := $(call cc-fullversion)
108cc-fullversion = $(shell $(CONFIG_SHELL) \
109 $(srctree)/scripts/gcc-version.sh -p $(CC))
110
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111# cc-ifversion
112# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
5de043f4 113cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
20a468b5 114
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115# ld-option
116# Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
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117ld-option = $(call try-run,\
118 $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
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119
120######
0b0bf7a3 121
beda9f3a 122###
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123# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
124# Usage:
125# $(Q)$(MAKE) $(build)=dir
126build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
127
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128# Prefix -I with $(srctree) if it is not an absolute path.
129addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
5de043f4 130
d9df92e2 131# Find all -I options and call addtree
beda9f3a 132flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
d9df92e2 133
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134# echo command.
135# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
bff288c1 136echo-cmd = $(if $($(quiet)cmd_$(1)),\
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137 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
138
139# printing commands
6176aa9a 140cmd = @$(echo-cmd) $(cmd_$(1))
8ec4b4ff 141
5de043f4 142# Add $(obj)/ for paths that are not absolute
bff288c1 143objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
0a504f25 144
8ec4b4ff 145###
5de043f4 146# if_changed - execute command if any prerequisite is newer than
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147# target, or command line has changed
148# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
149# including used config symbols
150# if_changed_rule - as if_changed but execute rule instead
151# See Documentation/kbuild/makefiles.txt for more info
152
153ifneq ($(KBUILD_NOCMDDEP),1)
beda9f3a 154# Check if both arguments has same arguments. Result is empty string if equal.
8ec4b4ff 155# User may override this check using make KBUILD_NOCMDDEP=1
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156arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
157 $(filter-out $(cmd_$@), $(cmd_$(1))) )
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158endif
159
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160# >'< substitution is for echo to work,
161# >$< substitution to preserve $ when reloading .cmd file
162# note: when using inline perl scripts [perl -e '...$$t=1;...']
163# in $(cmd_xxx) double $$ your perl vars
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164make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
165
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166# Find any prerequisites that is newer than target or that does not exist.
167# PHONY targets skipped in both cases.
168any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
169
5de043f4 170# Execute command if command has changed or prerequisite(s) are updated.
4f193362 171#
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172if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
173 @set -e; \
174 $(echo-cmd) $(cmd_$(1)); \
175 echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
8ec4b4ff 176
5de043f4 177# Execute the command and also postprocess generated .d dependencies file.
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178if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \
179 @set -e; \
180 $(echo-cmd) $(cmd_$(1)); \
181 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
182 rm -f $(depfile); \
183 mv -f $(dot-target).tmp $(dot-target).cmd)
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184
185# Usage: $(call if_changed_rule,foo)
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186# Will check if $(cmd_foo) or any of the prerequisites changed,
187# and if so will execute $(rule_foo).
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188if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \
189 @set -e; \
190 $(rule_$(1)))
191
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192###
193# why - tell why a a target got build
194# enabled by make V=2
195# Output (listed in the order they are checked):
196# (1) - due to target is PHONY
197# (2) - due to target missing
198# (3) - due to: file1.h file2.h
199# (4) - due to command line change
200# (5) - due to missing .cmd file
201# (6) - due to target not in $(targets)
202# (1) PHONY targets are always build
203# (2) No target, so we better build it
204# (3) Prerequisite is newer than target
205# (4) The command line stored in the file named dir/.target.cmd
206# differed from actual command line. This happens when compiler
207# options changes
208# (5) No dir/.target.cmd file (used to store command line)
209# (6) No dir/.target.cmd file and target not listed in $(targets)
210# This is a good hint that there is a bug in the kbuild file
211ifeq ($(KBUILD_VERBOSE),2)
212why = \
213 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \
214 $(if $(wildcard $@), \
215 $(if $(strip $(any-prereq)),- due to: $(any-prereq), \
216 $(if $(arg-check), \
217 $(if $(cmd_$@),- due to command line change, \
218 $(if $(filter $@, $(targets)), \
219 - due to missing .cmd file, \
220 - due to $(notdir $@) not in $$(targets) \
221 ) \
222 ) \
223 ) \
224 ), \
225 - due to target missing \
226 ) \
227 )
228
229echo-why = $(call escsq, $(strip $(why)))
230endif