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https://github.com/torvalds/linux.git
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adf1423698
Current gcc generates calls not jumps to noreturn functions. When that happens the return address can point to the next function, which confuses the unwinder. This patch works around it by marking asynchronous exception frames in contrast normal call frames in the unwind information. Then teach the unwinder to decode this. For normal call frames the unwinder now subtracts one from the address which avoids this problem. The standard libgcc unwinder uses the same trick. It doesn't include adjustment of the printed address (i.e. for the original example, it'd still be kernel_math_error+0 that gets displayed, but the unwinder wouldn't get confused anymore. This only works with binutils 2.6.17+ and some versions of H.J.Lu's 2.6.16 unfortunately because earlier binutils don't support .cfi_signal_frame [AK: added automatic detection of the new binutils and wrote description] Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de>
213 lines
8.2 KiB
Plaintext
213 lines
8.2 KiB
Plaintext
####
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# kbuild: Generic definitions
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# Convinient variables
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comma := ,
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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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# 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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# 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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echo ' 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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echo ' 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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# as-option
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# Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,)
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as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \
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-xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \
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else echo "$(2)"; fi ;)
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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 = $(shell if echo -e "$(1)" | $(AS) >/dev/null 2>&1 -W -Z -o astest$$$$.out ; \
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then echo "$(2)"; else echo "$(3)"; fi; \
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rm -f astest$$$$.out)
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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 = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
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> /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
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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 = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
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> /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
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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-version
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# Usage gcc-ver := $(call cc-version, $(CC))
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cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(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 if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \
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echo $(3); fi;)
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# ld-option
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# Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
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ld-option = $(shell if $(CC) $(1) \
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-nostdlib -o ldtest$$$$.out -xc /dev/null \
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> /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi; \
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rm -f ldtest$$$$.out)
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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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# Prefix -I with $(srctree) if it is not an absolute path
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addtree = $(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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# If quiet is set, only print short version of command
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cmd = @$(echo-cmd) $(cmd_$(1))
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# Add $(obj)/ for paths that is 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 in 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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endif
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# echo command. Short version is $(quiet) equals quiet, otherwise full command
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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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# >'< substitution is for echo to work,
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# >$< substitution to preserve $ when reloading .cmd file
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# note: when using inline perl scripts [perl -e '...$$t=1;...']
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# in $(cmd_xxx) double $$ your perl vars
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make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(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 prerequisitei(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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echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
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# execute the command and also postprocess generated .d dependencies
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# 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) changed, or any of the prequisites 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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