scripts/Kbuild.klibc - maze/klibc - Git at Google

 # ==========================================================================
 # Support for building klibc and related programs
 # ==========================================================================
 #
 # To create a kbuild file for a userspace program do the following:
 #
 # Kbuild:
 #
 # static-y := cat
 # # This will compile a file named cat.c -> the executable 'cat'
 # # The executable will be linked statically
 #
 # shared-y := cats
 # # This will compile a file named cats.c -> the executable 'cats'
 # # The executable will be linked shared
 #
 # If the userspace program consist of more files do the following:
 # Kbuild:
 #
 # static-y   := ipconfig
 # ipconfig-y := main.o netdev.c
 # So ipconfig will be linked statically using the two .o files
 # specified with ipconfig-y.
 #
 # To set directory wide CFLAGS use:
 # EXTRA_KLIBCCFLAGS := -DDEBUG
 # To set directory wide AFLAGS use:
 # EXTRA_KLIBCAFLAGS := -DDEBUG
 #
 # To set target specific CFLAGS (for .c files) use
 # KLIBCCFLAGS-main.o := -DDEBUG=3
 # To set target specific AFLAGS (for .s files) use
 # KLIBCAFLAGS-main.o := -DDEBUG=3

 src := $(obj)
 # Preset target and make sure it is a ':=' variable
 targets :=

 .phony: __build
 __build:

 # Generic Kbuild routines
 include $(srctree)/scripts/Kbuild.include

 # Defines used when compiling early userspace (klibc programs)
 # ---------------------------------------------------------------------------

 KLIBCREQFLAGS     :=
 KLIBCARCHREQFLAGS :=
 KLIBCOPTFLAGS     :=
 KLIBCWARNFLAGS    := -W -Wall -Wno-sign-compare -Wno-unused-parameter
 KLIBCSHAREDFLAGS  :=
 KLIBCBITSIZE      :=
 KLIBCLDFLAGS      :=

 # Arch specific definitions for klibc
 include $(KLIBCSRC)/arch/$(ARCH)/MCONFIG

 # klibc version
 KLIBCMAJOR        := $(shell cut -d. -f1 $(srctree)/version)
 KLIBCMINOR        := $(shell cut -d. -f2 $(srctree)/version)

 # FIXME - backwards compatibility. Remove when all MCONFIGs are corrected
 KLIBCREQFLAGS     += $(REQFLAGS)
 KLIBCARCHREQFLAGS += $(ARCHREQFLAGS)
 KLIBCOPTFLAGS     += $(OPTFLAGS)
 KLIBCWARNFLAGS    += $(WARNFLAGS)
 KLIBCSHAREDFLAGS  += $(SHAREDFLAGS)
 KLIBCBITSIZE      := $(strip $(KLIBCBITSIZE) $(BITSIZE))
 KLIBCLDFLAGS      += $(LDFLAGS)
 KLIBCROSS        := $(CROSS_COMPILE)

 # binutils
 KLIBCLD          := $(KLIBCROSS)ld
 KLIBCCC          := $(KLIBCROSS)gcc
 KLIBCAR          := $(KLIBCROSS)ar
 KLIBCRANLIB      := $(KLIBCROSS)ranlib
 KLIBCSTRIP       := $(KLIBCROSS)strip
 KLIBCNM          := $(KLIBCROSS)nm


 # klibc include paths
 KLIBCCPPFLAGS    := -I$(KLIBCINC)/arch/$(ARCH)         \
                     -I$(KLIBCINC)/bits$(KLIBCBITSIZE)  \
                     -I$(KLIBCINC)
 # kernel include paths
 KLIBCCPPFLAGS    += -I$(KLIBCKERNELSRC)include                              \
                      $(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include)
 # klibc definitions
 KLIBCDEFS        := -D__KLIBC__=$(KLIBCMAJOR)          \
 		    -D__KLIBC_MINOR__=$(KLIBCMINOR)    \
 		    -D_BITSIZE=$(KLIBCBITSIZE)
 KLIBCCPPFLAGS    += $(KLIBCDEFS)
 KLIBCCFLAGS      := $(KLIBCCPPFLAGS) $(KLIBCREQFLAGS) $(KLIBCARCHREQFLAGS)  \
                     $(KLIBCOPTFLAGS) $(KLIBCWARNFLAGS)
 KLIBCAFLAGS      := -D__ASSEMBLY__ $(KLIBCCFLAGS)
 KLIBCSTRIPFLAGS  := --strip-all -R .comment -R .note

 KLIBCLIBGCC      := $(shell $(KLIBCCC) --print-libgcc)
 KLIBCCRT0        := $(KLIBCOBJ)/arch/$(ARCH)/crt0.o
 KLIBCLIBC        := $(KLIBCOBJ)/libc.a
 KLIBCCRTSHARED   := $(KLIBCOBJ)/interp.o
 KLIBCLIBCSHARED  := $(KLIBCOBJ)/libc.so
 # How to tell the linker main() is the entrypoint
 KLIBCEMAIN	?= -e main

 #
 # This indicates the location of the final version of the shared library.
 # THIS MUST BE AN ABSOLUTE PATH WITH NO FINAL SLASH.
 # Leave this empty to make it the root.
 #
 SHLIBDIR = /lib

 export KLIBCLD KLIBCCC KLIBCAR KLIBCSTRIP KLIBCNM
 export KLIBCCFLAGS KLIBCAFLAGS KLIBCLIBGCC KLIBCSHAREDFLAGS KLIBCSTRIPFLAGS
 export KLIBCCRT0 KLIBCLIBC SHLIBDIR

 # kernel configuration
 include .config

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

 # Kbuild file in the directory that is being build
 include $(obj)/Kbuild

 #####
 # static-y + shared-y handling
 klibc-progs := $(static-y) $(shared-y)
 # klibc-progs based on a single .o file (with same name + .o)
 klibc-objs := $(foreach p, $(klibc-progs), $(if $($(p)-y),,$(p)))
 klibc-objs := $(addsuffix .o, $(klibc-objs))
 # klibc-progs which is based on several .o files
 klibc-multi := $(foreach p, $(klibc-progs), $(if $($(p)-y),$(p)))
 # objects used for klibc-progs with more then one .o file
 klibc-objs += $(foreach p, $(klibc-multi), $($(p)-y))
 # objects build in this dir
 klibc-real-objs := $(patsubst %/,,$(klibc-objs))
 # Directories we need to visit before klibc-objs are up-to-date
 klibc-dirs :=  $(patsubst %/,%,$(filter %/, $(klibc-objs)))
 # replace all dir/ with dir/lib.a
 klibc-objs := $(patsubst %/, %/lib.a, $(klibc-objs))

 targets += $(static-y) $(shared-y)

 # $(output-dirs) are a list of directories that contain object files
 output-dirs := $(dir $(klibc-dirs))
 output-dirs += $(foreach f, $(hostprogs-y) $(targets), \
                $(if $(dir $(f)), $(dir $(f))))
 output-dirs := $(strip $(sort $(filter-out ./,$(output-dirs))))

 # prefix so we get full dir
 static-y        := $(addprefix $(obj)/,$(static-y))
 shared-y        := $(addprefix $(obj)/,$(shared-y))
 klibc-objs      := $(addprefix $(obj)/,$(klibc-objs))
 klibc-real-objs := $(addprefix $(obj)/,$(klibc-real-objs))
 output-dirs     := $(addprefix $(obj)/,$(output-dirs))
 klibc-dirs      := $(addprefix $(obj)/,$(klibc-dirs))
 subdir-y        := $(addprefix $(obj)/,$(subdir-y))
 lib-y           := $(addprefix $(obj)/,$(lib-y))
 always          := $(addprefix $(obj)/,$(always))
 targets         := $(addprefix $(obj)/,$(targets))


 _klibccflags    = $(KLIBCCFLAGS) $(EXTRA_KLIBCCFLAGS) $(KLIBCCFLAGS_$(*F).o)
 _klibcaflags    = $(KLIBCAFLAGS) $(EXTRA_KLIBCAFLAGS) $(KLIBCAFLAGS_$(*F).o)

 klibccflags     = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(_klibccflags)
 klibcaflags     = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(_klibcaflags)

 # Create output directory if not already present
 _dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))

 # Create directories for object files if directory does not exist
 # Needed when lib-y := dir/file.o syntax is used
 _dummy := $(foreach d,$(output-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))

 # Do we have to make a lib.a in this dir?
 ifneq ($(strip $(lib-y) $(lib-n) $(lib-)),)
 lib-target := $(obj)/lib.a
 endif

 __build: $(subdir-y) $(lib-target) $(always)
 	@:

 # Compile C sources (.c)
 # ---------------------------------------------------------------------------

 quiet_cmd_cc_s_c = KLIBCCC $@
       cmd_cc_s_c = $(KLIBCCC) $(klibccflags) -S -o $@ $<

 %.s: %.c FORCE
 	$(call if_changed_dep,cc_s_c)

 quiet_cmd_cc_o_c = KLIBCCC $@
       cmd_cc_o_c = $(KLIBCCC) $(klibccflags) -c -o $@ $<

 %.o: %.c FORCE
 	$(call if_changed_dep,cc_o_c)

 # Compile assembler sources (.S)
 # ---------------------------------------------------------------------------

 quiet_cmd_as_o_S = KLIBCAS $@
       cmd_as_o_S = $(KLIBCCC) $(klibcaflags) -c -o $@ $<

 %.o: %.S FORCE
 	$(call if_changed_dep,as_o_S)

 targets += $(real-objs-y)

 #
 # Rule to compile a set of .o files into one .o file
 #
 ifdef lib-target
 quiet_cmd_link_o_target = LD      $@
 # If the list of objects to link is empty, just create an empty lib.a
 cmd_link_o_target = $(if $(strip $(lib-y)),\
                     rm -f $@; $(KLIBCAR) cru $@ $(filter $(lib-y), $^),\
                     rm -f $@; $(KLIBCAR) crs $@)

 $(lib-target): $(lib-y) FORCE
 	$(call if_changed,link_o_target)
 targets += $(lib-target) $(lib-y)
 endif # lib-target


 ifdef klibc-progs
 # Compile klibcspace programs for the target
 # ===========================================================================

 __build : $(klibc-dirs) $(static-y) $(shared-y)

 # Descend if needed
 $(sort $(addsuffix /lib.a,$(klibc-dirs))): $(klibc-dirs) ;

 # Define dependencies for link of progs
 # For the simple program:
 #	file.o => file
 # A program with multiple objects
 #	filea.o, fileb.o => file
 # A program with .o files in another dir
 #	dir/lib.a filea.o => file

 stripobj  = $(subst $(obj)/,,$@)
 addliba   = $(addprefix $(obj)/, $(patsubst %/, %/lib.a, $(1)))
 link-deps = $(if $($(stripobj)-y), $(call addliba, $($(stripobj)-y)), $@.o)

 quiet_cmd_ld-static = KLIBCLD $@
       cmd_ld-static = $(KLIBCLD) $(KLIBCLDFLAGS) -o $@    \
                        $(EXTRA_KLIBCLDFLAGS)              \
                        $(KLIBCCRT0)                       \
                        $(link-deps)                       \
                        $(KLIBCLIBC) $(KLIBCLIBGCC);       \
                        cp -f $@ $@.g;                     \
                        $(KLIBCSTRIP) $(KLIBCSTRIPFLAGS) $@


 $(static-y): $(klibc-objs) $(lib-target) FORCE
 	$(call if_changed,ld-static)

 quiet_cmd_ld-shared = KLIBCLD $@
       cmd_ld-shared = $(KLIBCLD) $(KLIBCLDFLAGS) -o $@    \
                        $(EXTRA_KLIBCLDFLAGS)              \
                        $(KLIBCEMAIN) $(KLIBCCRTSHARED)    \
                        $(link-deps)                       \
                        -R $(KLIBCLIBCSHARED) $(KLIBCLIBGCC);\
                        cp -f $@ $@.g;                     \
                        $(KLIBCSTRIP) $(KLIBCSTRIPFLAGS) $@


 $(shared-y): $(klibc-objs) $(lib-target) FORCE
 	$(call if_changed,ld-shared)

 targets += $(klibc-real-objs)
 endif

 # Compile programs on the host
 # ===========================================================================
 ifdef hostprogs-y
 include $(srctree)/scripts/Makefile.host
 endif

 # Descending
 # ---------------------------------------------------------------------------

 .PHONY: $(subdir-y) $(klibc-dirs)
 $(subdir-y) $(klibc-dirs):
 	$(Q)$(MAKE) $(klibc)=$@

 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 # ---------------------------------------------------------------------------

 .PHONY: FORCE

 FORCE:

 # Linking
 # Create a reloctable composite object file
 # ---------------------------------------------------------------------------
 quiet_cmd_klibcld = KLIBCLD $@
       cmd_klibcld = $(KLIBCLD) -r $(KLIBCLDFLAGS) \
                                 $(EXTRA_KLIBCLDFLAGS) $(KLIBCLDFLAGS_$(@F)) \
                                 $(filter-out FORCE,$^) -o $@


 # Link target to a new name
 # ---------------------------------------------------------------------------
 quiet_cmd_ln = LN      $@
       cmd_ln = rm -f $@ && ln $< $@

 # Strip target (remove all debugging info)
 quiet_cmd_strip = STRIP   $@
       cmd_strip = $(KLIBCSTRIP) $(KLIBCSTRIPFLAGS) $< -o $@


 # Read all saved command lines and dependencies for the $(targets) we
 # may be building above, using $(if_changed{,_dep}). As an
 # optimization, we don't need to read them if the target does not
 # exist, we will rebuild anyway in that case.
 targets := $(wildcard $(sort $(targets)))
 cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))

 ifneq ($(cmd_files),)
   include $(cmd_files)
 endif

 # Shorthand for $(Q)$(MAKE) -f scripts/Kbuild.klibc obj
 # Usage:
 # $(Q)$(MAKE) $(klibc)=dir
 klibc := -rR -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Kbuild.klibc obj
	# ==========================================================================
	# Support for building klibc and related programs
	# ==========================================================================
	#
	# To create a kbuild file for a userspace program do the following:
	#
	# Kbuild:
	#
	# static-y := cat
	# # This will compile a file named cat.c -> the executable 'cat'
	# # The executable will be linked statically
	#
	# shared-y := cats
	# # This will compile a file named cats.c -> the executable 'cats'
	# # The executable will be linked shared
	#
	# If the userspace program consist of more files do the following:
	# Kbuild:
	#
	# static-y := ipconfig
	# ipconfig-y := main.o netdev.c
	# So ipconfig will be linked statically using the two .o files
	# specified with ipconfig-y.
	#
	# To set directory wide CFLAGS use:
	# EXTRA_KLIBCCFLAGS := -DDEBUG
	# To set directory wide AFLAGS use:
	# EXTRA_KLIBCAFLAGS := -DDEBUG
	#
	# To set target specific CFLAGS (for .c files) use
	# KLIBCCFLAGS-main.o := -DDEBUG=3
	# To set target specific AFLAGS (for .s files) use
	# KLIBCAFLAGS-main.o := -DDEBUG=3

	src := $(obj)
	# Preset target and make sure it is a ':=' variable
	targets :=

	.phony: __build
	__build:

	# Generic Kbuild routines
	include $(srctree)/scripts/Kbuild.include

	# Defines used when compiling early userspace (klibc programs)
	# ---------------------------------------------------------------------------

	KLIBCREQFLAGS :=
	KLIBCARCHREQFLAGS :=
	KLIBCOPTFLAGS :=
	KLIBCWARNFLAGS := -W -Wall -Wno-sign-compare -Wno-unused-parameter
	KLIBCSHAREDFLAGS :=
	KLIBCBITSIZE :=
	KLIBCLDFLAGS :=

	# Arch specific definitions for klibc
	include $(KLIBCSRC)/arch/$(ARCH)/MCONFIG

	# klibc version
	KLIBCMAJOR := $(shell cut -d. -f1 $(srctree)/version)
	KLIBCMINOR := $(shell cut -d. -f2 $(srctree)/version)

	# FIXME - backwards compatibility. Remove when all MCONFIGs are corrected
	KLIBCREQFLAGS += $(REQFLAGS)
	KLIBCARCHREQFLAGS += $(ARCHREQFLAGS)
	KLIBCOPTFLAGS += $(OPTFLAGS)
	KLIBCWARNFLAGS += $(WARNFLAGS)
	KLIBCSHAREDFLAGS += $(SHAREDFLAGS)
	KLIBCBITSIZE := $(strip $(KLIBCBITSIZE) $(BITSIZE))
	KLIBCLDFLAGS += $(LDFLAGS)
	KLIBCROSS := $(CROSS_COMPILE)

	# binutils
	KLIBCLD := $(KLIBCROSS)ld
	KLIBCCC := $(KLIBCROSS)gcc
	KLIBCAR := $(KLIBCROSS)ar
	KLIBCRANLIB := $(KLIBCROSS)ranlib
	KLIBCSTRIP := $(KLIBCROSS)strip
	KLIBCNM := $(KLIBCROSS)nm


	# klibc include paths
	KLIBCCPPFLAGS := -I$(KLIBCINC)/arch/$(ARCH) \
	-I$(KLIBCINC)/bits$(KLIBCBITSIZE) \
	-I$(KLIBCINC)
	# kernel include paths
	KLIBCCPPFLAGS += -I$(KLIBCKERNELSRC)include \
	$(if $(KBUILD_SRC),-Iinclude2 -I$(srctree)/include)
	# klibc definitions
	KLIBCDEFS := -D__KLIBC__=$(KLIBCMAJOR) \
	-D__KLIBC_MINOR__=$(KLIBCMINOR) \
	-D_BITSIZE=$(KLIBCBITSIZE)
	KLIBCCPPFLAGS += $(KLIBCDEFS)
	KLIBCCFLAGS := $(KLIBCCPPFLAGS) $(KLIBCREQFLAGS) $(KLIBCARCHREQFLAGS) \
	$(KLIBCOPTFLAGS) $(KLIBCWARNFLAGS)
	KLIBCAFLAGS := -D__ASSEMBLY__ $(KLIBCCFLAGS)
	KLIBCSTRIPFLAGS := --strip-all -R .comment -R .note

	KLIBCLIBGCC := $(shell $(KLIBCCC) --print-libgcc)
	KLIBCCRT0 := $(KLIBCOBJ)/arch/$(ARCH)/crt0.o
	KLIBCLIBC := $(KLIBCOBJ)/libc.a
	KLIBCCRTSHARED := $(KLIBCOBJ)/interp.o
	KLIBCLIBCSHARED := $(KLIBCOBJ)/libc.so
	# How to tell the linker main() is the entrypoint
	KLIBCEMAIN ?= -e main

	#
	# This indicates the location of the final version of the shared library.
	# THIS MUST BE AN ABSOLUTE PATH WITH NO FINAL SLASH.
	# Leave this empty to make it the root.
	#
	SHLIBDIR = /lib

	export KLIBCLD KLIBCCC KLIBCAR KLIBCSTRIP KLIBCNM
	export KLIBCCFLAGS KLIBCAFLAGS KLIBCLIBGCC KLIBCSHAREDFLAGS KLIBCSTRIPFLAGS
	export KLIBCCRT0 KLIBCLIBC SHLIBDIR

	# kernel configuration
	include .config

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

	# Kbuild file in the directory that is being build
	include $(obj)/Kbuild

	#####
	# static-y + shared-y handling
	klibc-progs := $(static-y) $(shared-y)
	# klibc-progs based on a single .o file (with same name + .o)
	klibc-objs := $(foreach p, $(klibc-progs), $(if $($(p)-y),,$(p)))
	klibc-objs := $(addsuffix .o, $(klibc-objs))
	# klibc-progs which is based on several .o files
	klibc-multi := $(foreach p, $(klibc-progs), $(if $($(p)-y),$(p)))
	# objects used for klibc-progs with more then one .o file
	klibc-objs += $(foreach p, $(klibc-multi), $($(p)-y))
	# objects build in this dir
	klibc-real-objs := $(patsubst %/,,$(klibc-objs))
	# Directories we need to visit before klibc-objs are up-to-date
	klibc-dirs := $(patsubst %/,%,$(filter %/, $(klibc-objs)))
	# replace all dir/ with dir/lib.a
	klibc-objs := $(patsubst %/, %/lib.a, $(klibc-objs))

	targets += $(static-y) $(shared-y)

	# $(output-dirs) are a list of directories that contain object files
	output-dirs := $(dir $(klibc-dirs))
	output-dirs += $(foreach f, $(hostprogs-y) $(targets), \
	$(if $(dir $(f)), $(dir $(f))))
	output-dirs := $(strip $(sort $(filter-out ./,$(output-dirs))))

	# prefix so we get full dir
	static-y := $(addprefix $(obj)/,$(static-y))
	shared-y := $(addprefix $(obj)/,$(shared-y))
	klibc-objs := $(addprefix $(obj)/,$(klibc-objs))
	klibc-real-objs := $(addprefix $(obj)/,$(klibc-real-objs))
	output-dirs := $(addprefix $(obj)/,$(output-dirs))
	klibc-dirs := $(addprefix $(obj)/,$(klibc-dirs))
	subdir-y := $(addprefix $(obj)/,$(subdir-y))
	lib-y := $(addprefix $(obj)/,$(lib-y))
	always := $(addprefix $(obj)/,$(always))
	targets := $(addprefix $(obj)/,$(targets))


	_klibccflags = $(KLIBCCFLAGS) $(EXTRA_KLIBCCFLAGS) $(KLIBCCFLAGS_$(*F).o)
	_klibcaflags = $(KLIBCAFLAGS) $(EXTRA_KLIBCAFLAGS) $(KLIBCAFLAGS_$(*F).o)

	klibccflags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(_klibccflags)
	klibcaflags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(_klibcaflags)

	# Create output directory if not already present
	_dummy := $(shell [ -d $(obj) ] \|\| mkdir -p $(obj))

	# Create directories for object files if directory does not exist
	# Needed when lib-y := dir/file.o syntax is used
	_dummy := $(foreach d,$(output-dirs), $(shell [ -d $(d) ] \|\| mkdir -p $(d)))

	# Do we have to make a lib.a in this dir?
	ifneq ($(strip $(lib-y) $(lib-n) $(lib-)),)
	lib-target := $(obj)/lib.a
	endif

	__build: $(subdir-y) $(lib-target) $(always)
	@:

	# Compile C sources (.c)
	# ---------------------------------------------------------------------------

	quiet_cmd_cc_s_c = KLIBCCC $@
	cmd_cc_s_c = $(KLIBCCC) $(klibccflags) -S -o $@ $<

	%.s: %.c FORCE
	$(call if_changed_dep,cc_s_c)

	quiet_cmd_cc_o_c = KLIBCCC $@
	cmd_cc_o_c = $(KLIBCCC) $(klibccflags) -c -o $@ $<

	%.o: %.c FORCE
	$(call if_changed_dep,cc_o_c)

	# Compile assembler sources (.S)
	# ---------------------------------------------------------------------------

	quiet_cmd_as_o_S = KLIBCAS $@
	cmd_as_o_S = $(KLIBCCC) $(klibcaflags) -c -o $@ $<

	%.o: %.S FORCE
	$(call if_changed_dep,as_o_S)

	targets += $(real-objs-y)

	#
	# Rule to compile a set of .o files into one .o file
	#
	ifdef lib-target
	quiet_cmd_link_o_target = LD $@
	# If the list of objects to link is empty, just create an empty lib.a
	cmd_link_o_target = $(if $(strip $(lib-y)),\
	rm -f $@; $(KLIBCAR) cru $@ $(filter $(lib-y), $^),\
	rm -f $@; $(KLIBCAR) crs $@)

	$(lib-target): $(lib-y) FORCE
	$(call if_changed,link_o_target)
	targets += $(lib-target) $(lib-y)
	endif # lib-target


	ifdef klibc-progs
	# Compile klibcspace programs for the target
	# ===========================================================================

	__build : $(klibc-dirs) $(static-y) $(shared-y)

	# Descend if needed
	$(sort $(addsuffix /lib.a,$(klibc-dirs))): $(klibc-dirs) ;

	# Define dependencies for link of progs
	# For the simple program:
	# file.o => file
	# A program with multiple objects
	# filea.o, fileb.o => file
	# A program with .o files in another dir
	# dir/lib.a filea.o => file

	stripobj = $(subst $(obj)/,,$@)
	addliba = $(addprefix $(obj)/, $(patsubst %/, %/lib.a, $(1)))
	link-deps = $(if $($(stripobj)-y), $(call addliba, $($(stripobj)-y)), $@.o)

	quiet_cmd_ld-static = KLIBCLD $@
	cmd_ld-static = $(KLIBCLD) $(KLIBCLDFLAGS) -o $@ \
	$(EXTRA_KLIBCLDFLAGS) \
	$(KLIBCCRT0) \
	$(link-deps) \
	$(KLIBCLIBC) $(KLIBCLIBGCC); \
	cp -f $@ $@.g; \
	$(KLIBCSTRIP) $(KLIBCSTRIPFLAGS) $@


	$(static-y): $(klibc-objs) $(lib-target) FORCE
	$(call if_changed,ld-static)

	quiet_cmd_ld-shared = KLIBCLD $@
	cmd_ld-shared = $(KLIBCLD) $(KLIBCLDFLAGS) -o $@ \
	$(EXTRA_KLIBCLDFLAGS) \
	$(KLIBCEMAIN) $(KLIBCCRTSHARED) \
	$(link-deps) \
	-R $(KLIBCLIBCSHARED) $(KLIBCLIBGCC);\
	cp -f $@ $@.g; \
	$(KLIBCSTRIP) $(KLIBCSTRIPFLAGS) $@


	$(shared-y): $(klibc-objs) $(lib-target) FORCE
	$(call if_changed,ld-shared)

	targets += $(klibc-real-objs)
	endif

	# Compile programs on the host
	# ===========================================================================
	ifdef hostprogs-y
	include $(srctree)/scripts/Makefile.host
	endif

	# Descending
	# ---------------------------------------------------------------------------

	.PHONY: $(subdir-y) $(klibc-dirs)
	$(subdir-y) $(klibc-dirs):
	$(Q)$(MAKE) $(klibc)=$@

	# Add FORCE to the prequisites of a target to force it to be always rebuilt.
	# ---------------------------------------------------------------------------

	.PHONY: FORCE

	FORCE:

	# Linking
	# Create a reloctable composite object file
	# ---------------------------------------------------------------------------
	quiet_cmd_klibcld = KLIBCLD $@
	cmd_klibcld = $(KLIBCLD) -r $(KLIBCLDFLAGS) \
	$(EXTRA_KLIBCLDFLAGS) $(KLIBCLDFLAGS_$(@F)) \
	$(filter-out FORCE,$^) -o $@


	# Link target to a new name
	# ---------------------------------------------------------------------------
	quiet_cmd_ln = LN $@
	cmd_ln = rm -f $@ && ln $< $@

	# Strip target (remove all debugging info)
	quiet_cmd_strip = STRIP $@
	cmd_strip = $(KLIBCSTRIP) $(KLIBCSTRIPFLAGS) $< -o $@


	# Read all saved command lines and dependencies for the $(targets) we
	# may be building above, using $(if_changed{,_dep}). As an
	# optimization, we don't need to read them if the target does not
	# exist, we will rebuild anyway in that case.
	targets := $(wildcard $(sort $(targets)))
	cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))

	ifneq ($(cmd_files),)
	include $(cmd_files)
	endif

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