Skip to content
Snippets Groups Projects
Kbuild.include 10.4 KiB
Newer Older
  • Learn to ignore specific revisions
  • ####
    # kbuild: Generic definitions
    
    # Convenient variables
    comma   := ,
    squote  := '
    empty   :=
    space   := $(empty) $(empty)
    
    ###
    # 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)))
    
    # 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" is can be used as temporary file and
    # is automatically cleaned up.
    
    # modifed for U-Boot: prevent cc-option from leaving .*.su files
    
    try-run = $(shell set -e;		\
    	TMP="$(TMPOUT).$$$$.tmp";	\
    	TMPO="$(TMPOUT).$$$$.o";	\
    
    	TMPSU="$(TMPOUT).$$$$.su";	\
    
    	if ($(1)) >/dev/null 2>&1;	\
    	then echo "$(2)";		\
    	else echo "$(3)";		\
    	fi;				\
    
    	rm -f "$$TMP" "$$TMPO" "$$TMPSU")
    
    
    # as-option
    # Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
    
    as-option = $(call try-run,\
    	$(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 = $(call try-run,\
    	printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
    
    # cc-option
    # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
    
    cc-option = $(call try-run,\
    	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
    
    # cc-option-yn
    # Usage: flag := $(call cc-option-yn,-march=winchip-c6)
    cc-option-yn = $(call try-run,\
    	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
    
    # cc-option-align
    # Prefix align with either -falign or -malign
    cc-option-align = $(subst -functions=0,,\
    	$(call cc-option,-falign-functions=0,-malign-functions=0))
    
    # cc-disable-warning
    # Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
    cc-disable-warning = $(call try-run,\
    	$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
    
    # cc-version
    # Usage gcc-ver := $(call cc-version)
    cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
    
    # cc-fullversion
    # Usage gcc-ver := $(call cc-fullversion)
    cc-fullversion = $(shell $(CONFIG_SHELL) \
    	$(srctree)/scripts/gcc-version.sh -p $(CC))
    
    # cc-ifversion
    # Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
    cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
    
    
    # added for U-Boot
    binutils-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/binutils-version.sh $(AS))
    dtc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/dtc-version.sh $(DTC))
    
    
    # cc-ldoption
    # Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
    cc-ldoption = $(call try-run,\
    	$(CC) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))
    
    # ld-option
    # Usage: LDFLAGS += $(call ld-option, -X)
    ld-option = $(call try-run,\
    	$(CC) -x c /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
    
    # ar-option
    # Usage: KBUILD_ARFLAGS := $(call ar-option,D)
    # Important: no spaces around options
    ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2))
    
    ######
    
    ###
    # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
    # Usage:
    # $(Q)$(MAKE) $(build)=dir
    
    build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
    
    
    ###
    # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj=
    # Usage:
    # $(Q)$(MAKE) $(modbuiltin)=dir
    modbuiltin := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.modbuiltin obj
    
    # Prefix -I with $(srctree) if it is not an absolute path.
    # skip if -I has no parameter
    addtree = $(if $(patsubst -I%,%,$(1)), \
    $(if $(filter-out -I/%,$(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 has same arguments. Result is empty string if equal.
    # User may override this check using make KBUILD_NOCMDDEP=1
    arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
                        $(filter-out $(cmd_$@),   $(cmd_$(1))) )
    else
    arg-check = $(if $(strip $(cmd_$@)),,1)
    endif
    
    # >'< substitution is for echo to work,
    # >$< substitution to preserve $ when reloading .cmd file
    # note: when using inline perl scripts [perl -e '...$$t=1;...']
    # in $(cmd_xxx) double $$ your perl vars
    make-cmd = $(subst \\,\\\\,$(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(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));                                             \
    	echo '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;                                                             \
    	$(echo-cmd) $(cmd_$(1));                                             \
    	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
    	rm -f $(depfile);                                                    \
    	mv -f $(dot-target).tmp $(dot-target).cmd)
    
    # 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 a target got build
    #       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