FreeBSD/Linux Kernel Cross Reference
sys/scripts/Makefile.host

     # ==========================================================================
     # 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-y := conf
    # conf-objs  := conf.o libkconfig.so
    # libkconfig-objs := expr.o type.o
    # Will create a shared library named libkconfig.so that consists of
    # expr.o and type.o (they are both compiled as C code and the object files
    # are made as position independent code).
    # conf.c is compiled as a C program, and conf.o is linked together with
    # libkconfig.so as the executable conf.
    # Note: Shared libraries consisting of C++ files are not supported
    
    __hostprogs := $(sort $(hostprogs-y) $(hostprogs-m))
    
    # C code
    # Executables compiled from a single .c file
    host-csingle    := $(foreach m,$(__hostprogs),$(if $($(m)-objs),,$(m)))
    
    # C executables linked based on several .o files
    host-cmulti     := $(foreach m,$(__hostprogs),\
                       $(if $($(m)-cxxobjs),,$(if $($(m)-objs),$(m))))
    
    # Object (.o) files compiled from .c files
    host-cobjs      := $(sort $(foreach m,$(__hostprogs),$($(m)-objs)))
    
    # C++ code
    # C++ executables compiled from at least on .cc file
    # and zero or more .c files
    host-cxxmulti   := $(foreach m,$(__hostprogs),$(if $($(m)-cxxobjs),$(m)))
    
    # C++ Object (.o) files compiled from .cc files
    host-cxxobjs    := $(sort $(foreach m,$(host-cxxmulti),$($(m)-cxxobjs)))
    
    # Shared libaries (only .c supported)
    # Shared libraries (.so) - all .so files referenced in "xxx-objs"
    host-cshlib     := $(sort $(filter %.so, $(host-cobjs)))
    # Remove .so files from "xxx-objs"
    host-cobjs      := $(filter-out %.so,$(host-cobjs))
    
    #Object (.o) files used by the shared libaries
    host-cshobjs    := $(sort $(foreach m,$(host-cshlib),$($(m:.so=-objs))))
    
    # output directory for programs/.o files
    # hostprogs-y := tools/build may have been specified. Retrieve directory
    host-objdirs := $(foreach f,$(__hostprogs), $(if $(dir $(f)),$(dir $(f))))
    # directory of .o files from prog-objs notation
    host-objdirs += $(foreach f,$(host-cmulti),                  \
                        $(foreach m,$($(f)-objs),                \
                            $(if $(dir $(m)),$(dir $(m)))))
    # directory of .o files from prog-cxxobjs notation
    host-objdirs += $(foreach f,$(host-cxxmulti),                  \
                        $(foreach m,$($(f)-cxxobjs),                \
                            $(if $(dir $(m)),$(dir $(m)))))
    
    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-cshlib     := $(addprefix $(obj)/,$(host-cshlib))
    host-cshobjs    := $(addprefix $(obj)/,$(host-cshobjs))
    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 -> Executable
   quiet_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 -> executable
   quiet_cmd_host-cmulti   = HOSTLD  $@
         cmd_host-cmulti   = $(HOSTCC) $(HOSTLDFLAGS) -o $@ \
                             $(addprefix $(obj)/,$($(@F)-objs)) \
                             $(HOST_LOADLIBES) $(HOSTLOADLIBES_$(@F))
   $(host-cmulti): $(obj)/%: $(host-cobjs) $(host-cshlib) FORCE
           $(call if_changed,host-cmulti)
   
   # Create .o file from a single .c file
   # host-cobjs -> .o
   quiet_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 -> executable
   quiet_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) $(host-cshlib) FORCE
           $(call if_changed,host-cxxmulti)
   
   # Create .o file from a single .cc (C++) file
   quiet_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)
   
   # Compile .c file, create position independent .o file
   # host-cshobjs -> .o
   quiet_cmd_host-cshobjs  = HOSTCC  -fPIC $@
         cmd_host-cshobjs  = $(HOSTCC) $(hostc_flags) -fPIC -c -o $@ $<
   $(host-cshobjs): $(obj)/%.o: $(src)/%.c FORCE
           $(call if_changed_dep,host-cshobjs)
   
   # Link a shared library, based on position independent .o files
   # *.o -> .so shared library (host-cshlib)
   quiet_cmd_host-cshlib   = HOSTLLD -shared $@
         cmd_host-cshlib   = $(HOSTCC) $(HOSTLDFLAGS) -shared -o $@ \
                             $(addprefix $(obj)/,$($(@F:.so=-objs))) \
                             $(HOST_LOADLIBES) $(HOSTLOADLIBES_$(@F))
   $(host-cshlib): $(obj)/%: $(host-cshobjs) FORCE
           $(call if_changed,host-cshlib)
   
   targets += $(host-csingle)  $(host-cmulti) $(host-cobjs)\
              $(host-cxxmulti) $(host-cxxobjs) $(host-cshlib) $(host-cshobjs) 
   

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