# SPDX-License-Identifier: GPL-2.0
####
# kbuild: Generic definitions
# Convenient variables
comma := ,
quote := "
squote := '
empty :=
space := $(empty) $(empty)
space_escape := _-_SPACE_-_
pound := \#
###
# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
dot-target = $(dir $@).$(notdir $@)
###
# The temporary file to save gcc -MMD generated dependencies must not
# contain a comma
depfile = $(subst $(comma),_,$(dot-target).d)
###
# filename of target with directory and extension stripped
basetarget = $(basename $(notdir $@))
###
# real prerequisites without phony targets
real-prereqs = $(filter-out $(PHONY), $^)
###
# Escape single quote for use in echo statements
escsq = $(subst $(squote),'\$(squote)',$1)
###
# Quote a string to pass it to C files. foo => '"foo"'
stringify = $(squote)$(quote)$1$(quote)$(squote)
###
# 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:
#
# filechk_sample = echo $(KERNELRELEASE)
# version.h: FORCE
# $(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
define filechk
$(check-FORCE)
$(Q)set -e; \
mkdir -p $(dir $@); \
trap "rm -f $(dot-target).tmp" EXIT; \
{ $(filechk_$(1)); } > $(dot-target).tmp; \
if [ ! -r $@ ] || ! cmp -s $@ $(dot-target).tmp; then \
$(kecho) ' UPD $@'; \
mv -f $(dot-target).tmp $@; \
fi
endef
###
# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
# Usage:
# $(Q)$(MAKE) $(build)=dir
build := -f $(srctree)/scripts/Makefile.build obj
###
# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.dtbinst obj=
# Usage:
# $(Q)$(MAKE) $(dtbinst)=dir
dtbinst := -f $(srctree)/scripts/Makefile.dtbinst obj
###
# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=
# Usage:
# $(Q)$(MAKE) $(clean)=dir
clean := -f $(srctree)/scripts/Makefile.clean obj
# 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)';)
# sink stdout for 'make -s'
redirect :=
quiet_redirect :=
silent_redirect := exec >/dev/null;
# printing commands
cmd = @set -e; $(echo-cmd) $($(quiet)redirect) $(cmd_$(1))
###
# 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.rst for more info
ifneq ($(KBUILD_NOCMDDEP),1)
# Check if both commands are the same including their order. Result is empty
# string if equal. User may override this check using make KBUILD_NOCMDDEP=1
cmd-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \
$(subst $(space),$(space_escape),$(strip $(cmd_$1))))
else
cmd-check = $(if $(strip $(cmd_$@)),,1)
endif
# Replace >$< with >$$< to preserve $ when reloading the .cmd file
# (needed for make)
# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
# (needed for make)
# Replace >'< with >'\''< to be able to enclose the whole string in '...'
# (needed for the shell)
make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
# Find any prerequisites that are newer than target or that do not exist.
# (This is not true for now; $? should contain any non-existent prerequisites,
# but it does not work as expected when .SECONDARY is present. This seems a bug
# of GNU Make.)
# PHONY targets skipped in both cases.
newer-prereqs = $(filter-out $(PHONY),$?)
# It is a typical mistake to forget the FORCE prerequisite. Check it here so
# no more breakage will slip in.
check-FORCE = $(if $(filter FORCE, $^),,$(warning FORCE prerequisite is missing))
if-changed-cond = $(newer-prereqs)$(cmd-check)$(check-FORCE)
# Execute command if command has changed or prerequisite(s) are updated.
if_changed = $(if $(if-changed-cond), \
$(cmd); \
printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
# Execute the command and also postprocess generated .d dependencies file.
if_changed_dep = $(if $(if-changed-cond),$(cmd_and_fixdep),@:)
cmd_and_fixdep = \
$(cmd); \
scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\
rm -f $(depfile)
# 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 $(if-changed-cond),$(rule_$(1)),@:)
###
# why - tell why a target got built
# 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 $(newer-prereqs),- due to: $(newer-prereqs), \
$(if $(cmd-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
###############################################################################
# delete partially updated (i.e. corrupted) files on error
.DELETE_ON_ERROR:
# do not delete intermediate files automatically
.SECONDARY:
