# ==========================================================================# Building binaries on the host system# Binaries are used during the compilation of the kernel, for example# to preprocess a data file.## Both C and C++ are supported, but preferred language is C for such utilities.## Sample syntax (see Documentation/kbuild/makefiles.txt for reference)# hostprogs-y := bin2hex# Will compile bin2hex.c and create an executable named bin2hex## hostprogs-y    := lxdialog# lxdialog-objs := checklist.o lxdialog.o# Will compile lxdialog.c and checklist.c, and then link the executable# lxdialog, based on checklist.o and lxdialog.o## hostprogs-y      := qconf# qconf-cxxobjs   := qconf.o# qconf-objs      := menu.o# Will compile qconf as a C++ program, and menu as a C program.# They are linked as C++ code to the executable qconf __hostprogs := $(sort $(hostprogs-y) $(hostprogs-m)) # C code# Executables compiled from a single .c filehost-csingle	:= $(foreach m,$(__hostprogs), \			$(if $($(m)-objs)$($(m)-cxxobjs),,$(m))) # C executables linked based on several .o fileshost-cmulti	:= $(foreach m,$(__hostprogs),\		   $(if $($(m)-cxxobjs),,$(if $($(m)-objs),$(m)))) # Object (.o) files compiled from .c fileshost-cobjs	:= $(sort $(foreach m,$(__hostprogs),$($(m)-objs))) # C++ code# C++ executables compiled from at least one .cc file# and zero or more .c fileshost-cxxmulti	:= $(foreach m,$(__hostprogs),$(if $($(m)-cxxobjs),$(m))) # C++ Object (.o) files compiled from .cc fileshost-cxxobjs	:= $(sort $(foreach m,$(host-cxxmulti),$($(m)-cxxobjs))) # output directory for programs/.o files# hostprogs-y := tools/build may have been specified.# Retrieve also directory of .o files from prog-objs or prog-cxxobjs notationhost-objdirs := $(dir $(__hostprogs) $(host-cobjs) $(host-cxxobjs)) host-objdirs := $(strip $(sort $(filter-out ./,$(host-objdirs))))  __hostprogs     := $(addprefix $(obj)/,$(__hostprogs))host-csingle	:= $(addprefix $(obj)/,$(host-csingle))host-cmulti	:= $(addprefix $(obj)/,$(host-cmulti))host-cobjs	:= $(addprefix $(obj)/,$(host-cobjs))host-cxxmulti	:= $(addprefix $(obj)/,$(host-cxxmulti))host-cxxobjs	:= $(addprefix $(obj)/,$(host-cxxobjs))host-objdirs    := $(addprefix $(obj)/,$(host-objdirs)) obj-dirs += $(host-objdirs) ###### Handle options to gcc. Support building with separate output directory _hostc_flags   = $(HOSTCFLAGS)   $(HOST_EXTRACFLAGS)   \                 $(HOSTCFLAGS_$(basetarget).o)_hostcxx_flags = $(HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \                 $(HOSTCXXFLAGS_$(basetarget).o) ifeq ($(KBUILD_SRC),)__hostc_flags	= $(_hostc_flags)__hostcxx_flags	= $(_hostcxx_flags)else__hostc_flags	= -I$(obj) $(call flags,_hostc_flags)__hostcxx_flags	= -I$(obj) $(call flags,_hostcxx_flags)endif hostc_flags    = -Wp,-MD,$(depfile) $(__hostc_flags)hostcxx_flags  = -Wp,-MD,$(depfile) $(__hostcxx_flags) ###### Compile programs on the host # Create executable from a single .c file# host-csingle -> Executablequiet_cmd_host-csingle 	= HOSTCC  $@      cmd_host-csingle	= $(HOSTCC) $(hostc_flags) -o $@ $< \	  	$(HOST_LOADLIBES) $(HOSTLOADLIBES_$(@F))$(host-csingle): $(obj)/%: $(src)/%.c FORCE	$(call if_changed_dep,host-csingle) # Link an executable based on list of .o files, all plain c# host-cmulti -> executablequiet_cmd_host-cmulti	= HOSTLD  $@      cmd_host-cmulti	= $(HOSTCC) $(HOSTLDFLAGS) -o $@ \			  $(addprefix $(obj)/,$($(@F)-objs)) \			  $(HOST_LOADLIBES) $(HOSTLOADLIBES_$(@F))$(host-cmulti): $(obj)/%: $(host-cobjs) FORCE	$(call if_changed,host-cmulti) # Create .o file from a single .c file# host-cobjs -> .oquiet_cmd_host-cobjs	= HOSTCC  $@      cmd_host-cobjs	= $(HOSTCC) $(hostc_flags) -c -o $@ $<$(host-cobjs): $(obj)/%.o: $(src)/%.c FORCE	$(call if_changed_dep,host-cobjs) # Link an executable based on list of .o files, a mixture of .c and .cc# host-cxxmulti -> executablequiet_cmd_host-cxxmulti	= HOSTLD  $@      cmd_host-cxxmulti	= $(HOSTCXX) $(HOSTLDFLAGS) -o $@ \			  $(foreach o,objs cxxobjs,\			  $(addprefix $(obj)/,$($(@F)-$(o)))) \			  $(HOST_LOADLIBES) $(HOSTLOADLIBES_$(@F))$(host-cxxmulti): $(obj)/%: $(host-cobjs) $(host-cxxobjs) FORCE	$(call if_changed,host-cxxmulti) # Create .o file from a single .cc (C++) filequiet_cmd_host-cxxobjs	= HOSTCXX $@      cmd_host-cxxobjs	= $(HOSTCXX) $(hostcxx_flags) -c -o $@ $<$(host-cxxobjs): $(obj)/%.o: $(src)/%.cc FORCE	$(call if_changed_dep,host-cxxobjs) targets += $(host-csingle)  $(host-cmulti) $(host-cobjs)\	   $(host-cxxmulti) $(host-cxxobjs)