[mirror_ubuntu-bionic-kernel.git] / scripts / Kbuild.include

####
# kbuild: Generic definitions

# Convenient variables
comma   := ,
quote   := "
squote  := '
empty   :=
space   := $(empty) $(empty)
space_escape := _-_SPACE_-_
pound := \#
right_paren := )
left_paren := (

###
# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
dot-target = $(dir $@).$(notdir $@)

###
# The temporary file to save gcc -MD generated dependencies must not
# contain a comma
depfile = $(subst $(comma),_,$(dot-target).d)

###
# filename of target with directory and extension stripped
basetarget = $(basename $(notdir $@))

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

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

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

###
# 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;				\
	$(kecho) '  CHK     $@';		\
	mkdir -p $(dir $@);			\
	$(filechk_$(1)) < $< > $@.tmp;		\
	if [ -r $@ ] && cmp -s $@ $@.tmp; then	\
		rm -f $@.tmp;			\
	else					\
		$(kecho) '  UPD     $@';	\
		mv -f $@.tmp $@;		\
	fi
endef

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

# 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)))

# Tools for caching Makefile variables that are "expensive" to compute.
#
# Here we want to help deal with variables that take a long time to compute
# by making it easy to store these variables in a cache.
#
# The canonical example here is testing for compiler flags.  On a simple system
# each call to the compiler takes 10 ms, but on a system with a compiler that's
# called through various wrappers it can take upwards of 100 ms.  If we have
# 100 calls to the compiler this can take 1 second (on a simple system) or 10
# seconds (on a complicated system).
#
# The "cache" will be in Makefile syntax and can be directly included.
# Any time we try to reference a variable that's not in the cache we'll
# calculate it and store it in the cache for next time.

# Include values from last time
make-cache := $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/,$(if $(obj),$(obj)/)).cache.mk
$(make-cache): ;
-include $(make-cache)

cached-data := $(filter __cached_%, $(.VARIABLES))

# If cache exceeds 1000 lines, shrink it down to 500.
ifneq ($(word 1000,$(cached-data)),)
$(shell tail -n 500 $(make-cache) > $(make-cache).tmp; \
	mv $(make-cache).tmp $(make-cache))
endif

create-cache-dir := $(if $(KBUILD_SRC),$(if $(cache-data),,1))

# Usage: $(call __sanitize-opt,Hello=Hola$(comma)Goodbye Adios)
#
# Convert all '$', ')', '(', '\', '=', ' ', ',', ':' to '_'
__sanitize-opt = $(subst $$,_,$(subst $(right_paren),_,$(subst $(left_paren),_,$(subst \,_,$(subst =,_,$(subst $(space),_,$(subst $(comma),_,$(subst :,_,$(1)))))))))

# Usage:   $(call shell-cached,shell_command)
# Example: $(call shell-cached,md5sum /usr/bin/gcc)
#
# If we've already seen a call to this exact shell command (even in a
# previous invocation of make!) we'll return the value.  If not, we'll
# compute it and store the result for future runs.
#
# This is a bit of voodoo, but basic explanation is that if the variable
# was undefined then we'll evaluate the shell command and store the result
# into the variable.  We'll then store that value in the cache and finally
# output the value.
#
# NOTE: The $$(2) here isn't actually a parameter to __run-and-store.  We
# happen to know that the caller will have their shell command in $(2) so the
# result of "call"ing this will produce a reference to that $(2).  The reason
# for this strangeness is to avoid an extra level of eval (and escaping) of
# $(2).
define __run-and-store
ifeq ($(origin $(1)),undefined)
  $$(eval $(1) := $$(shell $$(2)))
ifeq ($(create-cache-dir),1)
  $$(shell mkdir -p $(dir $(make-cache)))
  $$(eval create-cache-dir :=)
endif
  $$(shell echo '$(1) := $$($(1))' >> $(make-cache))
endif
endef
__shell-cached = $(eval $(call __run-and-store,$(1)))$($(1))
shell-cached = $(call __shell-cached,__cached_$(call __sanitize-opt,$(1)),$(1))

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

# try-run
# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
# Exit code chooses option. "$$TMP" serves as a temporary file and is
# automatically cleaned up.
__try-run = set -e;			\
	TMP="$(TMPOUT).$$$$.tmp";	\
	TMPO="$(TMPOUT).$$$$.o";	\
	if ($(1)) >/dev/null 2>&1;	\
	then echo "$(2)";		\
	else echo "$(3)";		\
	fi;				\
	rm -f "$$TMP" "$$TMPO"

try-run = $(shell $(__try-run))

# try-run-cached
# This works like try-run, but the result is cached.
try-run-cached = $(call shell-cached,$(__try-run))

# as-option
# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)

as-option = $(call try-run-cached,\
	$(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))

# as-instr
# Usage: cflags-y += $(call as-instr,instr,option1,option2)

as-instr = $(call try-run-cached,\
	printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))

# __cc-option
# Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586)
__cc-option = $(call try-run-cached,\
	$(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4))

# 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))

# cc-option
# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)

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))

# cc-option-yn
# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
cc-option-yn = $(call try-run-cached,\
	$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)

# cc-disable-warning
# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
cc-disable-warning = $(call try-run-cached,\
	$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))

# cc-name
# Expands to either gcc or clang
cc-name = $(call shell-cached,$(CC) -v 2>&1 | grep -q "clang version" && echo clang || echo gcc)

# cc-version
cc-version = $(call shell-cached,$(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))

# cc-fullversion
cc-fullversion = $(call shell-cached,$(CONFIG_SHELL) \
	$(srctree)/scripts/gcc-version.sh -p $(CC))

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

# 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))

# cc-ldoption
# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
cc-ldoption = $(call try-run-cached,\
	$(CC) $(1) $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))

# ld-option
# Usage: LDFLAGS += $(call ld-option, -X)
ld-option = $(call try-run-cached,\
	$(CC) $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -x c /dev/null -c -o "$$TMPO"; \
	$(LD) $(LDFLAGS) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))

# ar-option
# Usage: KBUILD_ARFLAGS := $(call ar-option,D)
# Important: no spaces around options
ar-option = $(call try-run-cached, $(AR) rc$(1) "$$TMP",$(1),$(2))

# ld-version
# Note this is mainly for HJ Lu's 3 number binutil versions
ld-version = $(call shell-cached,$(LD) --version | $(srctree)/scripts/ld-version.sh)

# ld-ifversion
# Usage:  $(call ld-ifversion, -ge, 22252, y)
ld-ifversion = $(shell [ $(ld-version) $(1) $(2) ] && echo $(3) || echo $(4))

######

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

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

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

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

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

# Prefix -I with $(srctree) if it is not an absolute path.
# skip if -I has no parameter
addtree = $(if $(patsubst -I%,%,$(1)), \
$(if $(filter-out -I/% -I./% -I../%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1)),$(1)))

# Find all -I options and call addtree
flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))

# echo command.
# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
echo-cmd = $(if $($(quiet)cmd_$(1)),\
	echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)

# printing commands
cmd = @$(echo-cmd) $(cmd_$(1))

# Add $(obj)/ for paths that are not absolute
objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))

###
# if_changed      - execute command if any prerequisite is newer than
#                   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)
# 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))))
else
arg-check = $(if $(strip $(cmd_$@)),,1)
endif

# Replace >$< with >$$< to preserve $ when reloading the .cmd file
# (needed for make)
# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
# (needed for make)
# Replace >'< with >'\''< to be able to enclose the whole string in '...'
# (needed for the shell)
make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))

# 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 $^),$^)

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

# Execute the command and also postprocess generated .d dependencies file.
if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ),                  \
	@set -e;                                                             \
	$(cmd_and_fixdep), @:)

ifndef CONFIG_TRIM_UNUSED_KSYMS

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

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                                                       \
	  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__ $< ;;        \
	  boot*|build*|cpp_its_S|*cpp_lds_S|dtc|host*|vdso*) : ;;            \
	  *) echo "Don't know how to preprocess $(1)" >&2; false ;;          \
	esac | tr ";" "\n" | sed -rn 's/^.*=== __KSYM_(.*) ===.*$$/KSYM_\1/p'

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

# Usage: $(call if_changed_rule,foo)
# Will check if $(cmd_foo) or any of the prerequisites changed,
# and if so will execute $(rule_foo).
if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ),                 \
	@set -e;                                                             \
	$(rule_$(1)), @:)

###
# why - tell why a target got built
#       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

###############################################################################
#
# 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
#
###############################################################################
Commit	Line	Data
8ec4b4ff SR	1	####
	2	# kbuild: Generic definitions
	3
beda9f3a	4	# Convenient variables
8ec4b4ff	5	comma := ,
13338935	6	quote := "
d51bfb78	7	squote := '
8ec4b4ff SR	8	empty :=
8ec4b4ff SR	9	space := $(empty) $(empty)
9c8fa9bc	10	space_escape := _-_SPACE_-_
322d8e79	11	pound := \#
3298b690 DA	12	right_paren := )
3298b690 DA	13	left_paren := (
8ec4b4ff	14
48f1f058 SR	15	###
	16	# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
	17	dot-target = $(dir $@).$(notdir $@)
	18
8ec4b4ff SR	19	###
	20	# The temporary file to save gcc -MD generated dependencies must not
	21	# contain a comma
48f1f058	22	depfile = $(subst $(comma),_,$(dot-target).d)
8ec4b4ff	23
5e8d780d SR	24	###
	25	# filename of target with directory and extension stripped
	26	basetarget = $(basename $(notdir $@))
	27
e0318d85 AL	28	###
	29	# filename of first prerequisite with directory and extension stripped
	30	baseprereq = $(basename $(notdir $<))
	31
d51bfb78 SR	32	###
	33	# Escape single quote for use in echo statements
	34	escsq = $(subst $(squote),'\$(squote)',$1)
	35
5410ecc0 MF	36	###
	37	# Easy method for doing a status message
	38	kecho := :
	39	quiet_kecho := echo
	40	silent_kecho := :
	41	kecho := $($(quiet)kecho)
	42
8ec4b4ff SR	43	###
	44	# filechk is used to check if the content of a generated file is updated.
	45	# Sample usage:
	46	# define filechk_sample
	47	# echo $KERNELRELEASE
	48	# endef
	49	# version.h : Makefile
	50	# $(call filechk,sample)
	51	# The rule defined shall write to stdout the content of the new file.
	52	# The existing file will be compared with the new one.
	53	# - If no file exist it is created
	54	# - If the content differ the new file is used
	55	# - If they are equal no change, and no timestamp update
	56	# - stdin is piped in from the first prerequisite ($<) so one has
	57	# to specify a valid file as first prerequisite (often the kbuild file)
	58	define filechk
	59	$(Q)set -e; \
fd54f502	60	$(kecho) ' CHK $@'; \
8ec4b4ff SR	61	mkdir -p $(dir $@); \
	62	$(filechk_$(1)) < $< > $@.tmp; \
	63	if [ -r $@ ] && cmp -s $@ $@.tmp; then \
	64	rm -f $@.tmp; \
	65	else \
fd54f502	66	$(kecho) ' UPD $@'; \
8ec4b4ff SR	67	mv -f $@.tmp $@; \
	68	fi
	69	endef
	70
20a468b5	71	######
9d6e7a70	72	# gcc support functions
20a468b5 SR	73	# See documentation in Documentation/kbuild/makefiles.txt
20a468b5 SR	74
910b4046 SR	75	# cc-cross-prefix
	76	# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
	77	# Return first prefix where a prefix$(CC) is found in PATH.
	78	# If no $(CC) found in PATH with listed prefixes return nothing
	79	cc-cross-prefix = \
	80	$(word 1, $(foreach c,$(1), \
	81	$(shell set -e; \
	82	if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \
	83	echo $(c); \
	84	fi)))
	85
3298b690 DA	86	# Tools for caching Makefile variables that are "expensive" to compute.
	87	#
	88	# Here we want to help deal with variables that take a long time to compute
	89	# by making it easy to store these variables in a cache.
	90	#
	91	# The canonical example here is testing for compiler flags. On a simple system
	92	# each call to the compiler takes 10 ms, but on a system with a compiler that's
	93	# called through various wrappers it can take upwards of 100 ms. If we have
	94	# 100 calls to the compiler this can take 1 second (on a simple system) or 10
	95	# seconds (on a complicated system).
	96	#
	97	# The "cache" will be in Makefile syntax and can be directly included.
	98	# Any time we try to reference a variable that's not in the cache we'll
	99	# calculate it and store it in the cache for next time.
	100
	101	# Include values from last time
	102	make-cache := $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/,$(if $(obj),$(obj)/)).cache.mk
3298b690 DA	103	$(make-cache): ;
	104	-include $(make-cache)
	105
9a234a2e MY	106	cached-data := $(filter __cached_%, $(.VARIABLES))
9a234a2e MY	107
e17c400a	108	# If cache exceeds 1000 lines, shrink it down to 500.
9a234a2e	109	ifneq ($(word 1000,$(cached-data)),)
e17c400a MY	110	$(shell tail -n 500 $(make-cache) > $(make-cache).tmp; \
	111	mv $(make-cache).tmp $(make-cache))
	112	endif
	113
9a234a2e MY	114	create-cache-dir := $(if $(KBUILD_SRC),$(if $(cache-data),,1))
9a234a2e MY	115
3298b690 DA	116	# Usage: $(call __sanitize-opt,Hello=Hola$(comma)Goodbye Adios)
	117	#
	118	# Convert all '$', ')', '(', '\', '=', ' ', ',', ':' to '_'
	119	__sanitize-opt = $(subst $$,_,$(subst $(right_paren),_,$(subst $(left_paren),_,$(subst \,_,$(subst =,_,$(subst $(space),_,$(subst $(comma),_,$(subst :,_,$(1)))))))))
	120
	121	# Usage: $(call shell-cached,shell_command)
	122	# Example: $(call shell-cached,md5sum /usr/bin/gcc)
	123	#
	124	# If we've already seen a call to this exact shell command (even in a
	125	# previous invocation of make!) we'll return the value. If not, we'll
	126	# compute it and store the result for future runs.
	127	#
	128	# This is a bit of voodoo, but basic explanation is that if the variable
	129	# was undefined then we'll evaluate the shell command and store the result
	130	# into the variable. We'll then store that value in the cache and finally
	131	# output the value.
	132	#
	133	# NOTE: The $$(2) here isn't actually a parameter to __run-and-store. We
	134	# happen to know that the caller will have their shell command in $(2) so the
	135	# result of "call"ing this will produce a reference to that $(2). The reason
	136	# for this strangeness is to avoid an extra level of eval (and escaping) of
	137	# $(2).
	138	define __run-and-store
	139	ifeq ($(origin $(1)),undefined)
	140	$$(eval $(1) := $$(shell $$(2)))
9a234a2e MY	141	ifeq ($(create-cache-dir),1)
	142	$$(shell mkdir -p $(dir $(make-cache)))
	143	$$(eval create-cache-dir :=)
	144	endif
3298b690 DA	145	$$(shell echo '$(1) := $$($(1))' >> $(make-cache))
	146	endif
	147	endef
	148	__shell-cached = $(eval $(call __run-and-store,$(1)))$($(1))
	149	shell-cached = $(call __shell-cached,__cached_$(call __sanitize-opt,$(1)),$(1))
	150
beda9f3a RZ	151	# output directory for tests below
	152	TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
	153
	154	# try-run
	155	# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
312a3d09 C	156	# Exit code chooses option. "$$TMP" serves as a temporary file and is
312a3d09 C	157	# automatically cleaned up.
3298b690	158	__try-run = set -e; \
beda9f3a	159	TMP="$(TMPOUT).$$$$.tmp"; \
691ef3e7	160	TMPO="$(TMPOUT).$$$$.o"; \
beda9f3a RZ	161	if ($(1)) >/dev/null 2>&1; \
	162	then echo "$(2)"; \
	163	else echo "$(3)"; \
	164	fi; \
3298b690 DA	165	rm -f "$$TMP" "$$TMPO"
	166
	167	try-run = $(shell $(__try-run))
	168
	169	# try-run-cached
	170	# This works like try-run, but the result is cached.
	171	try-run-cached = $(call shell-cached,$(__try-run))
347a00fb	172
20a468b5	173	# as-option
bff288c1	174	# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
beda9f3a	175
3298b690	176	as-option = $(call try-run-cached,\
b1e0d8b7	177	$(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))
20a468b5	178
e2414910	179	# as-instr
bff288c1	180	# Usage: cflags-y += $(call as-instr,instr,option1,option2)
beda9f3a	181
3298b690	182	as-instr = $(call try-run-cached,\
b1e0d8b7	183	printf "%b\n" "$(1)" \| $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
e2414910	184
9f3f1fd2 MK	185	# __cc-option
9f3f1fd2 MK	186	# Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586)
3298b690	187	__cc-option = $(call try-run-cached,\
9f3f1fd2 MK	188	$(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4))
9f3f1fd2 MK	189
d26e9414 ER	190	# Do not attempt to build with gcc plugins during cc-option tests.
	191	# (And this uses delayed resolution so the flags will be up to date.)
	192	CC_OPTION_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS))
	193
20a468b5	194	# cc-option
bff288c1	195	# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
beda9f3a	196
9f3f1fd2 MK	197	cc-option = $(call __cc-option, $(CC),\
	198	$(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS),$(1),$(2))
	199
	200	# hostcc-option
	201	# Usage: cflags-y += $(call hostcc-option,-march=winchip-c6,-march=i586)
	202	hostcc-option = $(call __cc-option, $(HOSTCC),\
	203	$(HOSTCFLAGS) $(HOST_EXTRACFLAGS),$(1),$(2))
20a468b5 SR	204
20a468b5 SR	205	# cc-option-yn
bff288c1	206	# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
3298b690	207	cc-option-yn = $(call try-run-cached,\
c3f0d0bc	208	$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
20a468b5	209
8417da6f MM	210	# cc-disable-warning
8417da6f MM	211	# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
3298b690	212	cc-disable-warning = $(call try-run-cached,\
c3f0d0bc	213	$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
8417da6f	214
5631d9c4 MM	215	# cc-name
5631d9c4 MM	216	# Expands to either gcc or clang
3298b690	217	cc-name = $(call shell-cached,$(CC) -v 2>&1 \| grep -q "clang version" && echo clang \|\| echo gcc)
5631d9c4	218
20a468b5	219	# cc-version
3298b690	220	cc-version = $(call shell-cached,$(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
20a468b5	221
0ab2a272	222	# cc-fullversion
3298b690	223	cc-fullversion = $(call shell-cached,$(CONFIG_SHELL) \
0ab2a272 SB	224	$(srctree)/scripts/gcc-version.sh -p $(CC))
0ab2a272 SB	225
20a468b5 SR	226	# cc-ifversion
20a468b5 SR	227	# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
6dcb4e5e	228	cc-ifversion = $(shell [ $(cc-version) $(1) $(2) ] && echo $(3) \|\| echo $(4))
20a468b5	229
3f135e57 JP	230	# cc-if-fullversion
	231	# Usage: EXTRA_CFLAGS += $(call cc-if-fullversion, -lt, 040502, -O1)
	232	cc-if-fullversion = $(shell [ $(cc-fullversion) $(1) $(2) ] && echo $(3) \|\| echo $(4))
	233
f86fd306 SR	234	# cc-ldoption
f86fd306 SR	235	# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
3298b690	236	cc-ldoption = $(call try-run-cached,\
86a9df59	237	$(CC) $(1) $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))
5de043f4	238
691ef3e7 SR	239	# ld-option
691ef3e7 SR	240	# Usage: LDFLAGS += $(call ld-option, -X)
3298b690	241	ld-option = $(call try-run-cached,\
86a9df59 ND	242	$(CC) $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -x c /dev/null -c -o "$$TMPO"; \
86a9df59 ND	243	$(LD) $(LDFLAGS) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
691ef3e7	244
40df759e MM	245	# ar-option
	246	# Usage: KBUILD_ARFLAGS := $(call ar-option,D)
	247	# Important: no spaces around options
3298b690	248	ar-option = $(call try-run-cached, $(AR) rc$(1) "$$TMP",$(1),$(2))
40df759e	249
ccbef167	250	# ld-version
ccbef167	251	# Note this is mainly for HJ Lu's 3 number binutil versions
3298b690	252	ld-version = $(call shell-cached,$(LD) --version \| $(srctree)/scripts/ld-version.sh)
ccbef167 AK	253
	254	# ld-ifversion
	255	# Usage: $(call ld-ifversion, -ge, 22252, y)
6dcb4e5e	256	ld-ifversion = $(shell [ $(ld-version) $(1) $(2) ] && echo $(3) \|\| echo $(4))
ccbef167	257
5de043f4	258	######
0b0bf7a3	259
beda9f3a	260	###
8ec4b4ff SR	261	# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
	262	# Usage:
	263	# $(Q)$(MAKE) $(build)=dir
5b2389b4	264	build := -f $(srctree)/scripts/Makefile.build obj
8ec4b4ff	265
bc081dd6 MM	266	###
	267	# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj=
	268	# Usage:
	269	# $(Q)$(MAKE) $(modbuiltin)=dir
5b2389b4	270	modbuiltin := -f $(srctree)/scripts/Makefile.modbuiltin obj
bc081dd6	271
9fb5e537 RR	272	###
	273	# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.dtbinst obj=
	274	# Usage:
	275	# $(Q)$(MAKE) $(dtbinst)=dir
	276	dtbinst := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.dtbinst obj
	277
371fdc77 MY	278	###
	279	# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=
	280	# Usage:
	281	# $(Q)$(MAKE) $(clean)=dir
	282	clean := -f $(srctree)/scripts/Makefile.clean obj
	283
	284	###
1846dfbd	285	# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.headersinst obj=
371fdc77 MY	286	# Usage:
371fdc77 MY	287	# $(Q)$(MAKE) $(hdr-inst)=dir
1846dfbd	288	hdr-inst := -f $(srctree)/scripts/Makefile.headersinst obj
371fdc77	289
beda9f3a	290	# Prefix -I with $(srctree) if it is not an absolute path.
5b91c33c SR	291	# skip if -I has no parameter
5b91c33c SR	292	addtree = $(if $(patsubst -I%,%,$(1)), \
db547ef1	293	$(if $(filter-out -I/% -I./% -I../%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1)),$(1)))
5de043f4	294
d9df92e2	295	# Find all -I options and call addtree
beda9f3a	296	flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
d9df92e2	297
5de043f4 OV	298	# echo command.
5de043f4 OV	299	# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
bff288c1	300	echo-cmd = $(if $($(quiet)cmd_$(1)),\
5de043f4 OV	301	echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
	302
	303	# printing commands
6176aa9a	304	cmd = @$(echo-cmd) $(cmd_$(1))
8ec4b4ff	305
5de043f4	306	# Add $(obj)/ for paths that are not absolute
bff288c1	307	objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
0a504f25	308
8ec4b4ff	309	###
5de043f4	310	# if_changed - execute command if any prerequisite is newer than
8ec4b4ff SR	311	# target, or command line has changed
	312	# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
	313	# including used config symbols
	314	# if_changed_rule - as if_changed but execute rule instead
	315	# See Documentation/kbuild/makefiles.txt for more info
	316
	317	ifneq ($(KBUILD_NOCMDDEP),1)
9c8fa9bc MY	318	# Check if both arguments are the same including their order. Result is empty
	319	# string if equal. User may override this check using make KBUILD_NOCMDDEP=1
	320	arg-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \
	321	$(subst $(space),$(space_escape),$(strip $(cmd_$1))))
c4d5ee13 MM	322	else
c4d5ee13 MM	323	arg-check = $(if $(strip $(cmd_$@)),,1)
8ec4b4ff SR	324	endif
8ec4b4ff SR	325
164f0d2e MM	326	# Replace >$< with >$$< to preserve $ when reloading the .cmd file
164f0d2e MM	327	# (needed for make)
322d8e79	328	# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
164f0d2e MM	329	# (needed for make)
	330	# Replace >'< with >'\''< to be able to enclose the whole string in '...'
	331	# (needed for the shell)
322d8e79	332	make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
6176aa9a	333
48f1f058 SR	334	# Find any prerequisites that is newer than target or that does not exist.
	335	# PHONY targets skipped in both cases.
	336	any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
	337
5de043f4	338	# Execute command if command has changed or prerequisite(s) are updated.
48f1f058 SR	339	if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
	340	@set -e; \
	341	$(echo-cmd) $(cmd_$(1)); \
2aedcd09	342	printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
8ec4b4ff	343
5de043f4	344	# Execute the command and also postprocess generated .d dependencies file.
48f1f058 SR	345	if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \
48f1f058 SR	346	@set -e; \
e4aca459 NP	347	$(cmd_and_fixdep), @:)
e4aca459 NP	348
c1a95fda NP	349	ifndef CONFIG_TRIM_UNUSED_KSYMS
c1a95fda NP	350
e4aca459	351	cmd_and_fixdep = \
48f1f058 SR	352	$(echo-cmd) $(cmd_$(1)); \
	353	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
	354	rm -f $(depfile); \
e4aca459	355	mv -f $(dot-target).tmp $(dot-target).cmd;
8ec4b4ff	356
c1a95fda NP	357	else
	358
	359	# Filter out exported kernel symbol names from the preprocessor output.
	360	# See also __KSYM_DEPS__ in include/linux/export.h.
	361	# We disable the depfile generation here, so as not to overwrite the existing
	362	# depfile while fixdep is parsing it.
	363	flags_nodeps = $(filter-out -Wp$(comma)-M%, $($(1)))
	364	ksym_dep_filter = \
	365	case "$(1)" in \
366f4856 NP	366	cc_*_c\|cpp_i_c) \
	367	$(CPP) $(call flags_nodeps,c_flags) -D__KSYM_DEPS__ $< ;; \
	368	as_*_S\|cpp_s_S) \
	369	$(CPP) $(call flags_nodeps,a_flags) -D__KSYM_DEPS__ $< ;; \
0d070d2b	370	boot\|build\|cpp_its_S\|cpp_lds_S\|dtc\|host\|vdso*) : ;; \
366f4856	371	*) echo "Don't know how to preprocess $(1)" >&2; false ;; \
f110e0fe	372	esac \| tr ";" "\n" \| sed -rn 's/^.=== __KSYM_(.) ===.*$$/KSYM_\1/p'
c1a95fda NP	373
	374	cmd_and_fixdep = \
	375	$(echo-cmd) $(cmd_$(1)); \
	376	$(ksym_dep_filter) \| \
	377	scripts/basic/fixdep -e $(depfile) $@ '$(make-cmd)' \
	378	> $(dot-target).tmp; \
	379	rm -f $(depfile); \
	380	mv -f $(dot-target).tmp $(dot-target).cmd;
	381
	382	endif
	383
8ec4b4ff	384	# Usage: $(call if_changed_rule,foo)
beda9f3a RZ	385	# Will check if $(cmd_foo) or any of the prerequisites changed,
beda9f3a RZ	386	# and if so will execute $(rule_foo).
48f1f058 SR	387	if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \
48f1f058 SR	388	@set -e; \
2aedcd09	389	$(rule_$(1)), @:)
48f1f058	390
45d506bd	391	###
312a3d09	392	# why - tell why a target got built
45d506bd SR	393	# enabled by make V=2
	394	# Output (listed in the order they are checked):
	395	# (1) - due to target is PHONY
	396	# (2) - due to target missing
	397	# (3) - due to: file1.h file2.h
	398	# (4) - due to command line change
	399	# (5) - due to missing .cmd file
	400	# (6) - due to target not in $(targets)
	401	# (1) PHONY targets are always build
	402	# (2) No target, so we better build it
	403	# (3) Prerequisite is newer than target
	404	# (4) The command line stored in the file named dir/.target.cmd
	405	# differed from actual command line. This happens when compiler
	406	# options changes
	407	# (5) No dir/.target.cmd file (used to store command line)
	408	# (6) No dir/.target.cmd file and target not listed in $(targets)
	409	# This is a good hint that there is a bug in the kbuild file
	410	ifeq ($(KBUILD_VERBOSE),2)
	411	why = \
	412	$(if $(filter $@, $(PHONY)),- due to target is PHONY, \
	413	$(if $(wildcard $@), \
	414	$(if $(strip $(any-prereq)),- due to: $(any-prereq), \
	415	$(if $(arg-check), \
	416	$(if $(cmd_$@),- due to command line change, \
	417	$(if $(filter $@, $(targets)), \
	418	- due to missing .cmd file, \
	419	- due to $(notdir $@) not in $$(targets) \
	420	) \
	421	) \
	422	) \
	423	), \
	424	- due to target missing \
	425	) \
	426	)
	427
	428	echo-why = $(call escsq, $(strip $(why)))
	429	endif
3ee550f1 DW	430
	431	###############################################################################
	432	#
	433	# When a Kconfig string contains a filename, it is suitable for
	434	# passing to shell commands. It is surrounded by double-quotes, and
	435	# any double-quotes or backslashes within it are escaped by
	436	# backslashes.
	437	#
	438	# This is no use for dependencies or $(wildcard). We need to strip the
	439	# surrounding quotes and the escaping from quotes and backslashes, and
	440	# we do need to escape any spaces in the string. So, for example:
	441	#
	442	# Usage: $(eval $(call config_filename,FOO))
	443	#
	444	# Defines FOO_FILENAME based on the contents of the CONFIG_FOO option,
	445	# transformed as described above to be suitable for use within the
	446	# makefile.
	447	#
	448	# Also, if the filename is a relative filename and exists in the source
	449	# tree but not the build tree, define FOO_SRCPREFIX as $(srctree)/ to
	450	# be prefixed to both command invocation and dependencies.
	451	#
	452	# Note: We also print the filenames in the quiet_cmd_foo text, and
	453	# perhaps ought to have a version specially escaped for that purpose.
	454	# But it's only cosmetic, and $(patsubst "%",%,$(CONFIG_FOO)) is good
	455	# enough. It'll strip the quotes in the common case where there's no
	456	# space and it's a simple filename, and it'll retain the quotes when
	457	# there's a space. There are some esoteric cases in which it'll print
	458	# the wrong thing, but we don't really care. The actual dependencies
	459	# and commands do get it right, with various combinations of single
	460	# and double quotes, backslashes and spaces in the filenames.
	461	#
	462	###############################################################################
	463	#
3ee550f1 DW	464	define config_filename
	465	ifneq ($$(CONFIG_$(1)),"")
	466	$(1)_FILENAME := $$(subst \\,\,$$(subst \$$(quote),$$(quote),$$(subst $$(space_escape),\$$(space),$$(patsubst "%",%,$$(subst $$(space),$$(space_escape),$$(CONFIG_$(1)))))))
	467	ifneq ($$(patsubst /%,%,$$(firstword $$($(1)_FILENAME))),$$(firstword $$($(1)_FILENAME)))
	468	else
	469	ifeq ($$(wildcard $$($(1)_FILENAME)),)
	470	ifneq ($$(wildcard $$(srctree)/$$($(1)_FILENAME)),)
	471	$(1)_SRCPREFIX := $(srctree)/
	472	endif
	473	endif
	474	endif
	475	endif
	476	endef
	477	#
	478	###############################################################################