mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
164f0d2efa
Commit c353acba ("kbuild: make: fix if_changed when command contains
backslashes") attempted to handle backslashes in *.cmd files, but it
only handled double backslashes for some reason. Changing make-cmd to also
handle single backslashes fixes rebuilds with dash, but it breaks bash
again. The reason is that the two shells disagree about the
interpretation of backslash sequences in the echo builtin. The way out
of this is to print the command with printf '%s\n'. While at it,
document what the individual parts of make-cmd do and why.
Reported-and-tested-by: Konstantin Khlebnikov <koct9i@gmail.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
290 lines
10 KiB
Text
290 lines
10 KiB
Text
####
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# kbuild: Generic definitions
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# Convenient variables
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comma := ,
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quote := "
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squote := '
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empty :=
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space := $(empty) $(empty)
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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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# 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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# filename of target with directory and extension stripped
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basetarget = $(basename $(notdir $@))
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###
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# filename of first prerequisite with directory and extension stripped
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baseprereq = $(basename $(notdir $<))
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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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###
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# Easy method for doing a status message
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kecho := :
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quiet_kecho := echo
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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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######
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# gcc support functions
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# See documentation in Documentation/kbuild/makefiles.txt
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# cc-cross-prefix
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# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
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# Return first prefix where a prefix$(CC) is found in PATH.
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# If no $(CC) found in PATH with listed prefixes return nothing
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cc-cross-prefix = \
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$(word 1, $(foreach c,$(1), \
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$(shell set -e; \
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if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \
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echo $(c); \
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fi)))
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# output directory for tests below
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TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
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# try-run
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# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
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# Exit code chooses option. "$$TMP" is can be used as temporary file and
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# is automatically cleaned up.
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try-run = $(shell set -e; \
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TMP="$(TMPOUT).$$$$.tmp"; \
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TMPO="$(TMPOUT).$$$$.o"; \
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if ($(1)) >/dev/null 2>&1; \
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then echo "$(2)"; \
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else echo "$(3)"; \
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fi; \
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rm -f "$$TMP" "$$TMPO")
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# as-option
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# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
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as-option = $(call try-run,\
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$(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))
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# as-instr
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# Usage: cflags-y += $(call as-instr,instr,option1,option2)
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as-instr = $(call try-run,\
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printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
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# cc-option
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# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
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cc-option = $(call try-run,\
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$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
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# cc-option-yn
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# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
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cc-option-yn = $(call try-run,\
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$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
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# cc-option-align
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# Prefix align with either -falign or -malign
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cc-option-align = $(subst -functions=0,,\
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$(call cc-option,-falign-functions=0,-malign-functions=0))
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# cc-disable-warning
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# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
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cc-disable-warning = $(call try-run,\
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$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
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# cc-version
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# Usage gcc-ver := $(call cc-version)
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cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
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# cc-fullversion
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# Usage gcc-ver := $(call cc-fullversion)
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cc-fullversion = $(shell $(CONFIG_SHELL) \
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$(srctree)/scripts/gcc-version.sh -p $(CC))
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# cc-ifversion
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# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
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cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
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# cc-ldoption
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# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
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cc-ldoption = $(call try-run,\
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$(CC) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))
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# ld-option
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# Usage: LDFLAGS += $(call ld-option, -X)
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ld-option = $(call try-run,\
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$(CC) -x c /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
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# ar-option
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# Usage: KBUILD_ARFLAGS := $(call ar-option,D)
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# Important: no spaces around options
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ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2))
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# ld-version
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# Usage: $(call ld-version)
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# Note this is mainly for HJ Lu's 3 number binutil versions
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ld-version = $(shell $(LD) --version | $(srctree)/scripts/ld-version.sh)
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# ld-ifversion
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# Usage: $(call ld-ifversion, -ge, 22252, y)
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ld-ifversion = $(shell [ $(call ld-version) $(1) $(2) ] && echo $(3))
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######
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###
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# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
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# Usage:
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# $(Q)$(MAKE) $(build)=dir
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build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
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###
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# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj=
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# Usage:
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# $(Q)$(MAKE) $(modbuiltin)=dir
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modbuiltin := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.modbuiltin obj
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# Prefix -I with $(srctree) if it is not an absolute path.
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# skip if -I has no parameter
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addtree = $(if $(patsubst -I%,%,$(1)), \
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$(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1))
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# Find all -I options and call addtree
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flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
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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)))$(echo-why)';)
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# printing commands
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cmd = @$(echo-cmd) $(cmd_$(1))
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# Add $(obj)/ for paths that are not absolute
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objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
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###
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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_dep - as if_changed, but uses fixdep to reveal dependencies
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# including used config symbols
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# if_changed_rule - as if_changed but execute rule instead
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# See Documentation/kbuild/makefiles.txt for more info
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ifneq ($(KBUILD_NOCMDDEP),1)
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# Check if both arguments has same arguments. Result is empty string if equal.
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# User may override this check using make KBUILD_NOCMDDEP=1
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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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else
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arg-check = $(if $(strip $(cmd_$@)),,1)
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endif
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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 >\#< 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 \#,\\\#,$(subst $$,$$$$,$(cmd_$(1)))))
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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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# Execute command if command has changed or prerequisite(s) are updated.
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#
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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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# Execute the command and also postprocess generated .d dependencies 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)); \
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scripts/basic/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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# Usage: $(call if_changed_rule,foo)
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# Will check if $(cmd_foo) or any of the prerequisites changed,
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# and if so will execute $(rule_foo).
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if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \
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@set -e; \
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$(rule_$(1)))
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###
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# why - tell why a a target got build
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# enabled by make V=2
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# Output (listed in the order they are checked):
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# (1) - due to target is PHONY
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# (2) - due to target missing
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# (3) - due to: file1.h file2.h
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# (4) - due to command line change
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# (5) - due to missing .cmd file
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# (6) - due to target not in $(targets)
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# (1) PHONY targets are always build
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# (2) No target, so we better build it
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# (3) Prerequisite is newer than target
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# (4) The command line stored in the file named dir/.target.cmd
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# differed from actual command line. This happens when compiler
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# options changes
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# (5) No dir/.target.cmd file (used to store command line)
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# (6) No dir/.target.cmd file and target not listed in $(targets)
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# This is a good hint that there is a bug in the kbuild file
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ifeq ($(KBUILD_VERBOSE),2)
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why = \
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$(if $(filter $@, $(PHONY)),- due to target is PHONY, \
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$(if $(wildcard $@), \
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$(if $(strip $(any-prereq)),- due to: $(any-prereq), \
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$(if $(arg-check), \
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$(if $(cmd_$@),- due to command line change, \
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$(if $(filter $@, $(targets)), \
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- due to missing .cmd file, \
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- due to $(notdir $@) not in $$(targets) \
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) \
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) \
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) \
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), \
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- due to target missing \
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) \
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)
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echo-why = $(call escsq, $(strip $(why)))
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endif
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