Kbuild.include 15.2 KB
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####
# kbuild: Generic definitions

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# Convenient variables
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comma   := ,
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quote   := "
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squote  := '
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empty   :=
space   := $(empty) $(empty)
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space_escape := _-_SPACE_-_
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pound := \#
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###
# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
dot-target = $(dir $@).$(notdir $@)

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###
# The temporary file to save gcc -MD generated dependencies must not
# contain a comma
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depfile = $(subst $(comma),_,$(dot-target).d)
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###
# filename of target with directory and extension stripped
basetarget = $(basename $(notdir $@))

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###
# filename of first prerequisite with directory and extension stripped
baseprereq = $(basename $(notdir $<))

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###
# Escape single quote for use in echo statements
escsq = $(subst $(squote),'\$(squote)',$1)

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###
# Easy method for doing a status message
       kecho := :
 quiet_kecho := echo
silent_kecho := :
kecho := $($(quiet)kecho)

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###
# filechk is used to check if the content of a generated file is updated.
# Sample usage:
# define filechk_sample
#	echo $KERNELRELEASE
# endef
# version.h : Makefile
#	$(call filechk,sample)
# The rule defined shall write to stdout the content of the new file.
# The existing file will be compared with the new one.
# - If no file exist it is created
# - If the content differ the new file is used
# - If they are equal no change, and no timestamp update
# - stdin is piped in from the first prerequisite ($<) so one has
#   to specify a valid file as first prerequisite (often the kbuild file)
define filechk
	$(Q)set -e;				\
	mkdir -p $(dir $@);			\
	$(filechk_$(1)) < $< > $@.tmp;		\
	if [ -r $@ ] && cmp -s $@ $@.tmp; then	\
		rm -f $@.tmp;			\
	else					\
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		$(kecho) '  UPD     $@';	\
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		mv -f $@.tmp $@;		\
	fi
endef

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######
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# gcc support functions
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# See documentation in Documentation/kbuild/makefiles.txt

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# cc-cross-prefix
# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
# Return first prefix where a prefix$(CC) is found in PATH.
# If no $(CC) found in PATH with listed prefixes return nothing
cc-cross-prefix =  \
	$(word 1, $(foreach c,$(1),                                   \
		$(shell set -e;                                       \
		if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \
			echo $(c);                                    \
		fi)))

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# output directory for tests below
TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)

# try-run
# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
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# Exit code chooses option. "$$TMP" serves as a temporary file and is
# automatically cleaned up.
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try-run = $(shell set -e;		\
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	TMP="$(TMPOUT).$$$$.tmp";	\
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	TMPO="$(TMPOUT).$$$$.o";	\
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	if ($(1)) >/dev/null 2>&1;	\
	then echo "$(2)";		\
	else echo "$(3)";		\
	fi;				\
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	rm -f "$$TMP" "$$TMPO")
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# as-option
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# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
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as-option = $(call try-run,\
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	$(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))
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# as-instr
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# Usage: cflags-y += $(call as-instr,instr,option1,option2)
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as-instr = $(call try-run,\
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	printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
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# __cc-option
# Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586)
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__cc-option = $(call try-run,\
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	$(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4))

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# Do not attempt to build with gcc plugins during cc-option tests.
# (And this uses delayed resolution so the flags will be up to date.)
CC_OPTION_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS))

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# cc-option
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# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
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cc-option = $(call __cc-option, $(CC),\
	$(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS),$(1),$(2))

# hostcc-option
# Usage: cflags-y += $(call hostcc-option,-march=winchip-c6,-march=i586)
hostcc-option = $(call __cc-option, $(HOSTCC),\
	$(HOSTCFLAGS) $(HOST_EXTRACFLAGS),$(1),$(2))
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# cc-option-yn
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# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
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cc-option-yn = $(call try-run,\
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	$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
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# cc-disable-warning
# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
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cc-disable-warning = $(call try-run,\
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	$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
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# cc-name
# Expands to either gcc or clang
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cc-name = $(shell $(CC) -v 2>&1 | grep -q "clang version" && echo clang || echo gcc)
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# cc-version
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cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
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# cc-fullversion
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cc-fullversion = $(shell $(CONFIG_SHELL) \
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	$(srctree)/scripts/gcc-version.sh -p $(CC))

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# cc-ifversion
# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
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cc-ifversion = $(shell [ $(cc-version) $(1) $(2) ] && echo $(3) || echo $(4))
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# cc-if-fullversion
# Usage:  EXTRA_CFLAGS += $(call cc-if-fullversion, -lt, 040502, -O1)
cc-if-fullversion = $(shell [ $(cc-fullversion) $(1) $(2) ] && echo $(3) || echo $(4))

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# cc-ldoption
# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
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cc-ldoption = $(call try-run,\
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	$(CC) $(1) $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))
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# ld-option
# Usage: LDFLAGS += $(call ld-option, -X)
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ld-option = $(call try-run, $(LD) $(LDFLAGS) $(1) -v,$(1),$(2))
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# ar-option
# Usage: KBUILD_ARFLAGS := $(call ar-option,D)
# Important: no spaces around options
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ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2))
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# ld-version
# Note this is mainly for HJ Lu's 3 number binutil versions
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ld-version = $(shell $(LD) --version | $(srctree)/scripts/ld-version.sh)
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# ld-ifversion
# Usage:  $(call ld-ifversion, -ge, 22252, y)
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ld-ifversion = $(shell [ $(ld-version) $(1) $(2) ] && echo $(3) || echo $(4))
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######
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###
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# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
# Usage:
# $(Q)$(MAKE) $(build)=dir
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build := -f $(srctree)/scripts/Makefile.build obj
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###
# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj=
# Usage:
# $(Q)$(MAKE) $(modbuiltin)=dir
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modbuiltin := -f $(srctree)/scripts/Makefile.modbuiltin obj
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###
# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.dtbinst obj=
# Usage:
# $(Q)$(MAKE) $(dtbinst)=dir
dtbinst := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.dtbinst obj

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###
# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=
# Usage:
# $(Q)$(MAKE) $(clean)=dir
clean := -f $(srctree)/scripts/Makefile.clean obj

###
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# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.headersinst obj=
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# Usage:
# $(Q)$(MAKE) $(hdr-inst)=dir
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hdr-inst := -f $(srctree)/scripts/Makefile.headersinst obj
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# Prefix -I with $(srctree) if it is not an absolute path.
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# skip if -I has no parameter
addtree = $(if $(patsubst -I%,%,$(1)), \
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$(if $(filter-out -I/% -I./% -I../%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1)),$(1)),$(1))
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# Find all -I options and call addtree
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flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
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# echo command.
# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
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echo-cmd = $(if $($(quiet)cmd_$(1)),\
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	echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)

# printing commands
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cmd = @$(echo-cmd) $(cmd_$(1))
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# Add $(obj)/ for paths that are not absolute
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objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
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###
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# if_changed      - execute command if any prerequisite is newer than
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#                   target, or command line has changed
# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
#                   including used config symbols
# if_changed_rule - as if_changed but execute rule instead
# See Documentation/kbuild/makefiles.txt for more info

ifneq ($(KBUILD_NOCMDDEP),1)
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# Check if both arguments are the same including their order. Result is empty
# string if equal. User may override this check using make KBUILD_NOCMDDEP=1
arg-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \
                         $(subst $(space),$(space_escape),$(strip $(cmd_$1))))
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else
arg-check = $(if $(strip $(cmd_$@)),,1)
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endif

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# Replace >$< with >$$< to preserve $ when reloading the .cmd file
# (needed for make)
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# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
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# (needed for make)
# Replace >'< with >'\''< to be able to enclose the whole string in '...'
# (needed for the shell)
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make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
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# Find any prerequisites that is newer than target or that does not exist.
# PHONY targets skipped in both cases.
any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)

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# Execute command if command has changed or prerequisite(s) are updated.
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if_changed = $(if $(strip $(any-prereq) $(arg-check)),                       \
	@set -e;                                                             \
	$(echo-cmd) $(cmd_$(1));                                             \
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	printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
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# Execute the command and also postprocess generated .d dependencies file.
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if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ),                  \
	@set -e;                                                             \
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	$(cmd_and_fixdep), @:)

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ifndef CONFIG_TRIM_UNUSED_KSYMS

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cmd_and_fixdep =                                                             \
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	$(echo-cmd) $(cmd_$(1));                                             \
	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
	rm -f $(depfile);                                                    \
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	mv -f $(dot-target).tmp $(dot-target).cmd;
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else

# Filter out exported kernel symbol names from the preprocessor output.
# See also __KSYM_DEPS__ in include/linux/export.h.
# We disable the depfile generation here, so as not to overwrite the existing
# depfile while fixdep is parsing it.
flags_nodeps = $(filter-out -Wp$(comma)-M%, $($(1)))
ksym_dep_filter =                                                            \
	case "$(1)" in                                                       \
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	  cc_*_c|cpp_i_c)                                                    \
	    $(CPP) $(call flags_nodeps,c_flags) -D__KSYM_DEPS__ $< ;;        \
	  as_*_S|cpp_s_S)                                                    \
	    $(CPP) $(call flags_nodeps,a_flags) -D__KSYM_DEPS__ $< ;;        \
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	  boot*|build*|cpp_its_S|*cpp_lds_S|dtc|host*|vdso*) : ;;            \
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	  *) echo "Don't know how to preprocess $(1)" >&2; false ;;          \
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	esac | tr ";" "\n" | sed -n 's/^.*=== __KSYM_\(.*\) ===.*$$/_\1/p'
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cmd_and_fixdep =                                                             \
	$(echo-cmd) $(cmd_$(1));                                             \
	$(ksym_dep_filter) |                                                 \
		scripts/basic/fixdep -e $(depfile) $@ '$(make-cmd)'          \
			> $(dot-target).tmp;	                             \
	rm -f $(depfile);                                                    \
	mv -f $(dot-target).tmp $(dot-target).cmd;

endif

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# Usage: $(call if_changed_rule,foo)
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# Will check if $(cmd_foo) or any of the prerequisites changed,
# and if so will execute $(rule_foo).
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if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ),                 \
	@set -e;                                                             \
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	$(rule_$(1)), @:)
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###
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# why - tell why a target got built
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#       enabled by make V=2
#       Output (listed in the order they are checked):
#          (1) - due to target is PHONY
#          (2) - due to target missing
#          (3) - due to: file1.h file2.h
#          (4) - due to command line change
#          (5) - due to missing .cmd file
#          (6) - due to target not in $(targets)
# (1) PHONY targets are always build
# (2) No target, so we better build it
# (3) Prerequisite is newer than target
# (4) The command line stored in the file named dir/.target.cmd
#     differed from actual command line. This happens when compiler
#     options changes
# (5) No dir/.target.cmd file (used to store command line)
# (6) No dir/.target.cmd file and target not listed in $(targets)
#     This is a good hint that there is a bug in the kbuild file
ifeq ($(KBUILD_VERBOSE),2)
why =                                                                        \
    $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
        $(if $(wildcard $@),                                                 \
            $(if $(strip $(any-prereq)),- due to: $(any-prereq),             \
                $(if $(arg-check),                                           \
                    $(if $(cmd_$@),- due to command line change,             \
                        $(if $(filter $@, $(targets)),                       \
                            - due to missing .cmd file,                      \
                            - due to $(notdir $@) not in $$(targets)         \
                         )                                                   \
                     )                                                       \
                 )                                                           \
             ),                                                              \
             - due to target missing                                         \
         )                                                                   \
     )

echo-why = $(call escsq, $(strip $(why)))
endif
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###############################################################################
#
# When a Kconfig string contains a filename, it is suitable for
# passing to shell commands. It is surrounded by double-quotes, and
# any double-quotes or backslashes within it are escaped by
# backslashes.
#
# This is no use for dependencies or $(wildcard). We need to strip the
# surrounding quotes and the escaping from quotes and backslashes, and
# we *do* need to escape any spaces in the string. So, for example:
#
# Usage: $(eval $(call config_filename,FOO))
#
# Defines FOO_FILENAME based on the contents of the CONFIG_FOO option,
# transformed as described above to be suitable for use within the
# makefile.
#
# Also, if the filename is a relative filename and exists in the source
# tree but not the build tree, define FOO_SRCPREFIX as $(srctree)/ to
# be prefixed to *both* command invocation and dependencies.
#
# Note: We also print the filenames in the quiet_cmd_foo text, and
# perhaps ought to have a version specially escaped for that purpose.
# But it's only cosmetic, and $(patsubst "%",%,$(CONFIG_FOO)) is good
# enough.  It'll strip the quotes in the common case where there's no
# space and it's a simple filename, and it'll retain the quotes when
# there's a space. There are some esoteric cases in which it'll print
# the wrong thing, but we don't really care. The actual dependencies
# and commands *do* get it right, with various combinations of single
# and double quotes, backslashes and spaces in the filenames.
#
###############################################################################
#
define config_filename
ifneq ($$(CONFIG_$(1)),"")
$(1)_FILENAME := $$(subst \\,\,$$(subst \$$(quote),$$(quote),$$(subst $$(space_escape),\$$(space),$$(patsubst "%",%,$$(subst $$(space),$$(space_escape),$$(CONFIG_$(1)))))))
ifneq ($$(patsubst /%,%,$$(firstword $$($(1)_FILENAME))),$$(firstword $$($(1)_FILENAME)))
else
ifeq ($$(wildcard $$($(1)_FILENAME)),)
ifneq ($$(wildcard $$(srctree)/$$($(1)_FILENAME)),)
$(1)_SRCPREFIX := $(srctree)/
endif
endif
endif
endif
endef
#
###############################################################################