###
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# build: Generic definitions
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#
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# Lots of this code have been borrowed or heavily inspired from parts
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# of kbuild code, which is not credited, but mostly developed by:
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#
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# Copyright (C) Sam Ravnborg <sam@mars.ravnborg.org>, 2015
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# Copyright (C) Linus Torvalds <torvalds@linux-foundation.org>, 2015
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#
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###
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# Convenient variables
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comma := ,
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squote := '
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pound := \#
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###
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# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
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dot-target = $(dir $@).$(notdir $@)
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###
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# filename of target with directory and extension stripped
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basetarget = $(basename $(notdir $@))
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###
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# The temporary file to save gcc -MD generated dependencies must not
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# contain a comma
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depfile = $(subst $(comma),_,$(dot-target).d)
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###
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# Check if both arguments has same arguments. Result is empty string if equal.
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arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
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$(filter-out $(cmd_$@), $(cmd_$(1))) )
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###
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# Escape single quote for use in echo statements
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escsq = $(subst $(squote),'\$(squote)',$1)
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# Echo command
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# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
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echo-cmd = $(if $($(quiet)cmd_$(1)),\
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echo ' $(call escsq,$($(quiet)cmd_$(1)))';)
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###
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# Replace >$< with >$$< to preserve $ when reloading the .cmd file
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# (needed for make)
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# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
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# (needed for make)
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# Replace >'< with >'\''< to be able to enclose the whole string in '...'
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# (needed for the shell)
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make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
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###
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# Find any prerequisites that is newer than target or that does not exist.
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# PHONY targets skipped in both cases.
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any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
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###
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# Copy dependency data into .cmd file
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# - gcc -M dependency info
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# - command line to create object 'cmd_object :='
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dep-cmd = $(if $(wildcard $(fixdep)), \
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$(fixdep) $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp; \
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rm -f $(depfile); \
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mv -f $(dot-target).tmp $(dot-target).cmd, \
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printf '$(pound) cannot find fixdep (%s)\n' $(fixdep) > $(dot-target).cmd; \
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printf '$(pound) using basic dep data\n\n' >> $(dot-target).cmd; \
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cat $(depfile) >> $(dot-target).cmd; \
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printf '\n%s\n' 'cmd_$@ := $(make-cmd)' >> $(dot-target).cmd)
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###
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# if_changed_dep - execute command if any prerequisite is newer than
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# target, or command line has changed and update
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# dependencies in the cmd file
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if_changed_dep = $(if $(strip $(any-prereq) $(arg-check)), \
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@set -e; \
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$(echo-cmd) $(cmd_$(1)) && $(dep-cmd))
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# if_changed - execute command if any prerequisite is newer than
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# target, or command line has changed
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if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
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@set -e; \
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$(echo-cmd) $(cmd_$(1)); \
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printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
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###
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# C flags to be used in rule definitions, includes:
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# - depfile generation
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# - global $(CFLAGS)
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# - per target C flags
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# - per object C flags
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# - BUILD_STR macro to allow '-D"$(variable)"' constructs
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c_flags_1 = -Wp,-MD,$(depfile) -Wp,-MT,$@ $(CFLAGS) -I$(dir $@) -D"BUILD_STR(s)=\#s" -D"KBUILD_NAME=BUILD_STR($(basetarget))" $(CFLAGS_$(basetarget).o) $(CFLAGS_$(obj))
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c_flags_2 = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(c_flags_1))
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c_flags = $(filter-out $(CFLAGS_REMOVE_$(obj)), $(c_flags_2))
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cxx_flags = -Wp,-MD,$(depfile) -Wp,-MT,$@ $(CXXFLAGS) -I$(dir $@) -D"BUILD_STR(s)=\#s" $(CXXFLAGS_$(basetarget).o) $(CXXFLAGS_$(obj))
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###
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## HOSTCC C flags
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host_c_flags = -Wp,-MD,$(depfile) -Wp,-MT,$@ $(CHOSTFLAGS) -D"BUILD_STR(s)=\#s" $(CHOSTFLAGS_$(basetarget).o) $(CHOSTFLAGS_$(obj))
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###
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# Easy method for doing a status message
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kecho := echo
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quiet_kecho := :
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silent_kecho := :
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kecho := $($(quiet)kecho)
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###
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# filechk is used to check if the content of a generated file is updated.
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# Sample usage:
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# define filechk_sample
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# echo $KERNELRELEASE
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# endef
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# version.h : Makefile
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# $(call filechk,sample)
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# The rule defined shall write to stdout the content of the new file.
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# The existing file will be compared with the new one.
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# - If no file exist it is created
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# - If the content differ the new file is used
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# - If they are equal no change, and no timestamp update
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# - stdin is piped in from the first prerequisite ($<) so one has
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# to specify a valid file as first prerequisite (often the kbuild file)
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define filechk
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$(Q)set -e; \
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$(kecho) ' CHK $@'; \
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mkdir -p $(dir $@); \
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$(filechk_$(1)) < $< > $@.tmp; \
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if [ -r $@ ] && cmp -s $@ $@.tmp; then \
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rm -f $@.tmp; \
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else \
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$(kecho) ' UPD $@'; \
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mv -f $@.tmp $@; \
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fi
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endef
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