scripts/Kbuild.klibc - pub/scm/libs/klibc/klibc - Git at Google

 # ==========================================================================
 # Support for building klibc programs and klibc library
 # ==========================================================================
 #
 # 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 composite files do the following:
 # Kbuild:
 #
 # static-y := kinit
 # kinit-y  := main.o netdev.c
 # So kinit will be linked statically using the two .o files
 # specified with kinit-y.
 #
 # Are part of the program located in a sub-directory do like this:
 # kinit-y += ipconfig/
 #
 # And in the subdirectory:
 # ipconfig/Kbuild:
 # lib-y := packet.o dhcp_proto.o
 # # All .o files listed with lib-y will be used to create a single .a file.
 # # The .a file is created before any subdirectories are visited so it
 # # may be used in the sub-directory programs.
 #
 #####
 # For a klibc libary file do like this
 # klibc/Kbuild
 # klib-y := error.o pipe.o zlib/
 #
 #####
 # Handling of compiler/linker options
 #
 # 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:

 # Read .config if it exist, otherwise ignore
 -include $(objtree)/.config

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

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

 KLIBCREQFLAGS     := $(call cc-option, -fno-stack-protector, ) \
                      $(call cc-option, -fwrapv, ) \
                      $(call cc-option, -fno-PIE, ) \
                      $(call cc-option, -fno-builtin-bcmp, ) \
                      $(call cc-option, -fcommon, ) \
                      -ggdb
 KLIBCARCHREQFLAGS :=
 KLIBCOPTFLAGS     :=
 KLIBCWARNFLAGS    := -W -Wall -Wno-sign-compare -Wno-unused-parameter
 KLIBCSHAREDFLAGS  :=
 KLIBCBITSIZE      :=
 KLIBCLDFLAGS      :=
 KLIBCCFLAGS       :=

 # Defaults for arch to override
 KLIBCARCHINCFLAGS =
 KLIBCCRTSHARED    := $(KLIBCOBJ)/interp.o

 LD_IS_LLD         := $(shell $(LD) --version 2>&1 | grep LLD)
 LD_IMAGE_BASE_OPT := $(if $(LD_IS_LLD),--image-base,-Ttext-segment)

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

 # include/asm-* architecture
 KLIBCASMARCH	  ?= $(KLIBCARCH)

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

 # binutils
 KLIBCLD          := $(LD)
 KLIBCCC          := $(CC)
 KLIBCAR          := $(AR)

 KLIBCRANLIB      := $(RANLIB) -D
 KLIBCSTRIP       := $(if $(CONFIG_DEBUG_INFO),true,$(STRIP))
 KLIBCNM          := $(NM)
 KLIBCOBJCOPY     := $(OBJCOPY)
 KLIBCOBJDUMP     := $(OBJDUMP)

 # klibc include paths
 KLIBCCPPFLAGS    := -nostdinc -iwithprefix include \
                     -I$(KLIBCINC)/arch/$(KLIBCARCHDIR)	\
                     -I$(KLIBCINC)/bits$(KLIBCBITSIZE)	\
                     -I$(KLIBCOBJ)/../include		\
                     -I$(KLIBCINC)
 ifeq ($(cc-name),clang)
 KLIBCCPPFLAGS    += -I$(shell $(KLIBCCC) $(KLIBCCFLAGS) --print-file-name=include)
 endif

 # kernel include paths
 KLIBCKERNELSRC	 ?= $(srctree)
 KLIBCCPPFLAGS    += -I$(KLIBCKERNELSRC)/include		\
                      $(if $(KBUILD_SRC),-I$(srctree)/include)  \
 		     $(KLIBCARCHINCFLAGS)

 # compiler/assembler option for whether we want an executable stack
 KLIBCSTACKFLAGS  := -Wa,--$(if $(filter n,$(KLIBCEXECSTACK)),no)execstack

 # klibc definitions
 KLIBCDEFS        += -D__KLIBC__=$(KLIBCMAJOR)          \
 		    -D__KLIBC_MINOR__=$(KLIBCMINOR)    \
 		    -D_BITSIZE=$(KLIBCBITSIZE)
 KLIBCCPPFLAGS    += $(KLIBCDEFS)
 KLIBCCFLAGS      += $(KLIBCCPPFLAGS) $(KLIBCREQFLAGS) $(KLIBCARCHREQFLAGS)  \
                     $(KLIBCOPTFLAGS) $(KLIBCSTACKFLGS) $(KLIBCWARNFLAGS)
 KLIBCAFLAGS      += -D__ASSEMBLY__ $(KLIBCCFLAGS)
 KLIBCSTRIPFLAGS  += --strip-all -R .comment -R .note

 KLIBCLIBGCC_DEF  := $(shell $(KLIBCCC) $(KLIBCCFLAGS) $(if $(filter gcc,$(cc-name)),--print-libgcc,--print-libgcc-file-name))
 KLIBCLIBGCC      ?= $(KLIBCLIBGCC_DEF)
 KLIBCCRT0        := $(KLIBCOBJ)/arch/$(KLIBCARCHDIR)/crt0.o
 KLIBCLIBC        := $(KLIBCOBJ)/libc.a
 KLIBCLIBCSHARED  := $(KLIBCOBJ)/libc.so
 # How to tell the linker main() is the entrypoint
 KLIBCEMAIN	 ?= -e main

 ifdef CONFIG_DEBUG_INFO
 KLIBCLDFLAGS     += --build-id=sha1
 endif

 #
 # 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

 # 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 $(srctree)/$(obj)/Kbuild

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

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

 #####
 # klib-y handling
 # .o files to build in this dir
 klib-real-objs := $(patsubst %/,,$(klib-y))
 # Directories we need to visit before libs are up-to-date
 klib-dirs := $(patsubst %/,%,$(filter %/, $(klib-y)))
 # replace all dir/ with dir/klib.list
 klib-objs := $(patsubst %/, %/klib.list, $(klib-y))

 # $(output-dirs) are a list of directories that contain object files
 output-dirs := $(dir $(kprog-dirs) $(kprog-objs))
 output-dirs += $(foreach f, $(hostprogs-y) $(targets), \
                $(if $(dir $(f)), $(dir $(f))))
 output-dirs += $(dir $(klib-objs))
 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))
 kprog-objs      := $(addprefix $(obj)/,$(kprog-objs))
 kprog-real-objs := $(addprefix $(obj)/,$(kprog-real-objs))
 output-dirs     := $(addprefix $(obj)/,$(output-dirs))
 kprog-dirs      := $(addprefix $(obj)/,$(kprog-dirs))
 subdir-y        := $(addprefix $(obj)/,$(subdir-y))
 always          := $(addprefix $(obj)/,$(always))
 targets         := $(addprefix $(obj)/,$(targets))
 lib-y           := $(addprefix $(obj)/,$(lib-y))
 klib-y          := $(addprefix $(obj)/,$(klib-y))
 klib-objs       := $(addprefix $(obj)/,$(klib-objs))
 klib-real-objs  := $(addprefix $(obj)/,$(klib-real-objs))
 klib-dirs       := $(addprefix $(obj)/,$(klib-dirs))

 #####
 # Handle options to gcc. Support building with separate output directory

 __klibccflags    = $(KLIBCCFLAGS) $(EXTRA_KLIBCCFLAGS) $(KLIBCCFLAGS_$(*F).o)
 __klibcaflags    = $(KLIBCAFLAGS) $(EXTRA_KLIBCAFLAGS) $(KLIBCAFLAGS_$(*F).o)

 _klibccflags    = $(call flags,__klibccflags)
 _klibcaflags    = $(call flags,__klibcaflags)

 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)
 	$(Q):

 # 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)

 quiet_cmd_cc_i_c = CPP     $@
       cmd_cc_i_c = $(KLIBCCC) -E $(klibccflags) -o $@ $<
 %.i: %.c FORCE
 	$(call if_changed_dep,cc_i_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) Dcr $@ $(filter $(lib-y), $^),\
                     rm -f $@; $(KLIBCAR) Dcrs $@)

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

 #
 # Create klib.list
 #
 # Do we have to create a klibc library file in this dir?
 ifneq ($(strip $(klib-y) $(klib-n) $(klib-)),)
 klib-target := $(obj)/klib.list
 endif

 ifdef klib-target
 # include this in build
 __build: $(klib-target) $(klib-dirs)

 # descend if needed
 $(sort $(addsuffix /klib.list,$(klib-dirs))): $(klib-dirs) ;

 # create klib.list
 quiet_cmd_klib-list = LIST    $@
       cmd_klib-list = echo $(klib-real-objs) > $@
 $(klib-target): $(klib-objs) FORCE
 	$(call if_changed,klib-list)
 targets += $(klib-target) $(klib-real-objs)
 endif # klib-target

 ifdef kprogs
 # Compile klibc-programs for the target
 # ===========================================================================

 __build : $(kprog-dirs) $(static-y)
 ifdef KLIBCSHAREDFLAGS
 __build : $(shared-y)
 endif

 # Descend if needed
 $(sort $(addsuffix /lib.a,$(kprog-dirs))): $(kprog-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) \
 	    $(call objectify,$($(stripobj)-lib))

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


 $(static-y): $(kprog-objs) $(lib-target) $(KLIBCCRT0) $(KLIBCLIBC) FORCE
 	$(call if_changed,ld-static)

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


 $(shared-y): $(kprog-objs) $(lib-target) $(KLIBCCRTSHARED) \
                                          $(KLIBCLIBCSHARED) FORCE
 	$(call if_changed,ld-shared)

 # Do not try to build KLIBC libaries if we are building klibc
 ifeq ($(klibc-build),)
 $(KLIBCCRT0) $(KLIBCLIBC): ;
 $(KLIBCCRTSHARED) $(KLIBCLIBCSHARED): ;
 endif

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

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

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

 PHONY += $(subdir-y) $(kprog-dirs) $(klib-dirs)
 $(sort $(subdir-y) $(kprog-dirs) $(klib-dirs)): $(lib-target)
 	$(Q)$(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 $(srctree)/scripts/Kbuild.klibc obj

 # Declare the contents of the PHONY variable as phony.  We keep the variable for
 # if_changed.
 .PHONY: $(PHONY)
	# ==========================================================================
	# Support for building klibc programs and klibc library
	# ==========================================================================
	#
	# 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 composite files do the following:
	# Kbuild:
	#
	# static-y := kinit
	# kinit-y := main.o netdev.c
	# So kinit will be linked statically using the two .o files
	# specified with kinit-y.
	#
	# Are part of the program located in a sub-directory do like this:
	# kinit-y += ipconfig/
	#
	# And in the subdirectory:
	# ipconfig/Kbuild:
	# lib-y := packet.o dhcp_proto.o
	# # All .o files listed with lib-y will be used to create a single .a file.
	# # The .a file is created before any subdirectories are visited so it
	# # may be used in the sub-directory programs.
	#
	#####
	# For a klibc libary file do like this
	# klibc/Kbuild
	# klib-y := error.o pipe.o zlib/
	#
	#####
	# Handling of compiler/linker options
	#
	# 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:

	# Read .config if it exist, otherwise ignore
	-include $(objtree)/.config

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

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

	KLIBCREQFLAGS := $(call cc-option, -fno-stack-protector, ) \
	$(call cc-option, -fwrapv, ) \
	$(call cc-option, -fno-PIE, ) \
	$(call cc-option, -fno-builtin-bcmp, ) \
	$(call cc-option, -fcommon, ) \
	-ggdb
	KLIBCARCHREQFLAGS :=
	KLIBCOPTFLAGS :=
	KLIBCWARNFLAGS := -W -Wall -Wno-sign-compare -Wno-unused-parameter
	KLIBCSHAREDFLAGS :=
	KLIBCBITSIZE :=
	KLIBCLDFLAGS :=
	KLIBCCFLAGS :=

	# Defaults for arch to override
	KLIBCARCHINCFLAGS =
	KLIBCCRTSHARED := $(KLIBCOBJ)/interp.o

	LD_IS_LLD := $(shell $(LD) --version 2>&1 \| grep LLD)
	LD_IMAGE_BASE_OPT := $(if $(LD_IS_LLD),--image-base,-Ttext-segment)

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

	# include/asm-* architecture
	KLIBCASMARCH ?= $(KLIBCARCH)

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

	# binutils
	KLIBCLD := $(LD)
	KLIBCCC := $(CC)
	KLIBCAR := $(AR)

	KLIBCRANLIB := $(RANLIB) -D
	KLIBCSTRIP := $(if $(CONFIG_DEBUG_INFO),true,$(STRIP))
	KLIBCNM := $(NM)
	KLIBCOBJCOPY := $(OBJCOPY)
	KLIBCOBJDUMP := $(OBJDUMP)

	# klibc include paths
	KLIBCCPPFLAGS := -nostdinc -iwithprefix include \
	-I$(KLIBCINC)/arch/$(KLIBCARCHDIR) \
	-I$(KLIBCINC)/bits$(KLIBCBITSIZE) \
	-I$(KLIBCOBJ)/../include \
	-I$(KLIBCINC)
	ifeq ($(cc-name),clang)
	KLIBCCPPFLAGS += -I$(shell $(KLIBCCC) $(KLIBCCFLAGS) --print-file-name=include)
	endif

	# kernel include paths
	KLIBCKERNELSRC ?= $(srctree)
	KLIBCCPPFLAGS += -I$(KLIBCKERNELSRC)/include \
	$(if $(KBUILD_SRC),-I$(srctree)/include) \
	$(KLIBCARCHINCFLAGS)

	# compiler/assembler option for whether we want an executable stack
	KLIBCSTACKFLAGS := -Wa,--$(if $(filter n,$(KLIBCEXECSTACK)),no)execstack

	# klibc definitions
	KLIBCDEFS += -D__KLIBC__=$(KLIBCMAJOR) \
	-D__KLIBC_MINOR__=$(KLIBCMINOR) \
	-D_BITSIZE=$(KLIBCBITSIZE)
	KLIBCCPPFLAGS += $(KLIBCDEFS)
	KLIBCCFLAGS += $(KLIBCCPPFLAGS) $(KLIBCREQFLAGS) $(KLIBCARCHREQFLAGS) \
	$(KLIBCOPTFLAGS) $(KLIBCSTACKFLGS) $(KLIBCWARNFLAGS)
	KLIBCAFLAGS += -D__ASSEMBLY__ $(KLIBCCFLAGS)
	KLIBCSTRIPFLAGS += --strip-all -R .comment -R .note

	KLIBCLIBGCC_DEF := $(shell $(KLIBCCC) $(KLIBCCFLAGS) $(if $(filter gcc,$(cc-name)),--print-libgcc,--print-libgcc-file-name))
	KLIBCLIBGCC ?= $(KLIBCLIBGCC_DEF)
	KLIBCCRT0 := $(KLIBCOBJ)/arch/$(KLIBCARCHDIR)/crt0.o
	KLIBCLIBC := $(KLIBCOBJ)/libc.a
	KLIBCLIBCSHARED := $(KLIBCOBJ)/libc.so
	# How to tell the linker main() is the entrypoint
	KLIBCEMAIN ?= -e main

	ifdef CONFIG_DEBUG_INFO
	KLIBCLDFLAGS += --build-id=sha1
	endif

	#
	# 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

	# 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 $(srctree)/$(obj)/Kbuild

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

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

	#####
	# klib-y handling
	# .o files to build in this dir
	klib-real-objs := $(patsubst %/,,$(klib-y))
	# Directories we need to visit before libs are up-to-date
	klib-dirs := $(patsubst %/,%,$(filter %/, $(klib-y)))
	# replace all dir/ with dir/klib.list
	klib-objs := $(patsubst %/, %/klib.list, $(klib-y))

	# $(output-dirs) are a list of directories that contain object files
	output-dirs := $(dir $(kprog-dirs) $(kprog-objs))
	output-dirs += $(foreach f, $(hostprogs-y) $(targets), \
	$(if $(dir $(f)), $(dir $(f))))
	output-dirs += $(dir $(klib-objs))
	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))
	kprog-objs := $(addprefix $(obj)/,$(kprog-objs))
	kprog-real-objs := $(addprefix $(obj)/,$(kprog-real-objs))
	output-dirs := $(addprefix $(obj)/,$(output-dirs))
	kprog-dirs := $(addprefix $(obj)/,$(kprog-dirs))
	subdir-y := $(addprefix $(obj)/,$(subdir-y))
	always := $(addprefix $(obj)/,$(always))
	targets := $(addprefix $(obj)/,$(targets))
	lib-y := $(addprefix $(obj)/,$(lib-y))
	klib-y := $(addprefix $(obj)/,$(klib-y))
	klib-objs := $(addprefix $(obj)/,$(klib-objs))
	klib-real-objs := $(addprefix $(obj)/,$(klib-real-objs))
	klib-dirs := $(addprefix $(obj)/,$(klib-dirs))

	#####
	# Handle options to gcc. Support building with separate output directory

	__klibccflags = $(KLIBCCFLAGS) $(EXTRA_KLIBCCFLAGS) $(KLIBCCFLAGS_$(*F).o)
	__klibcaflags = $(KLIBCAFLAGS) $(EXTRA_KLIBCAFLAGS) $(KLIBCAFLAGS_$(*F).o)

	_klibccflags = $(call flags,__klibccflags)
	_klibcaflags = $(call flags,__klibcaflags)

	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)
	$(Q):

	# 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)

	quiet_cmd_cc_i_c = CPP $@
	cmd_cc_i_c = $(KLIBCCC) -E $(klibccflags) -o $@ $<
	%.i: %.c FORCE
	$(call if_changed_dep,cc_i_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) Dcr $@ $(filter $(lib-y), $^),\
	rm -f $@; $(KLIBCAR) Dcrs $@)

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

	#
	# Create klib.list
	#
	# Do we have to create a klibc library file in this dir?
	ifneq ($(strip $(klib-y) $(klib-n) $(klib-)),)
	klib-target := $(obj)/klib.list
	endif

	ifdef klib-target
	# include this in build
	__build: $(klib-target) $(klib-dirs)

	# descend if needed
	$(sort $(addsuffix /klib.list,$(klib-dirs))): $(klib-dirs) ;

	# create klib.list
	quiet_cmd_klib-list = LIST $@
	cmd_klib-list = echo $(klib-real-objs) > $@
	$(klib-target): $(klib-objs) FORCE
	$(call if_changed,klib-list)
	targets += $(klib-target) $(klib-real-objs)
	endif # klib-target

	ifdef kprogs
	# Compile klibc-programs for the target
	# ===========================================================================

	__build : $(kprog-dirs) $(static-y)
	ifdef KLIBCSHAREDFLAGS
	__build : $(shared-y)
	endif

	# Descend if needed
	$(sort $(addsuffix /lib.a,$(kprog-dirs))): $(kprog-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) \
	$(call objectify,$($(stripobj)-lib))

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


	$(static-y): $(kprog-objs) $(lib-target) $(KLIBCCRT0) $(KLIBCLIBC) FORCE
	$(call if_changed,ld-static)

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


	$(shared-y): $(kprog-objs) $(lib-target) $(KLIBCCRTSHARED) \
	$(KLIBCLIBCSHARED) FORCE
	$(call if_changed,ld-shared)

	# Do not try to build KLIBC libaries if we are building klibc
	ifeq ($(klibc-build),)
	$(KLIBCCRT0) $(KLIBCLIBC): ;
	$(KLIBCCRTSHARED) $(KLIBCLIBCSHARED): ;
	endif

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

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

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

	PHONY += $(subdir-y) $(kprog-dirs) $(klib-dirs)
	$(sort $(subdir-y) $(kprog-dirs) $(klib-dirs)): $(lib-target)
	$(Q)$(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 $(srctree)/scripts/Kbuild.klibc obj

	# Declare the contents of the PHONY variable as phony. We keep the variable for
	# if_changed.
	.PHONY: $(PHONY)