linux/scripts/Kbuild.include
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   1# SPDX-License-Identifier: GPL-2.0
   2####
   3# kbuild: Generic definitions
   4
   5# Convenient variables
   6comma   := ,
   7quote   := "
   8squote  := '
   9empty   :=
  10space   := $(empty) $(empty)
  11space_escape := _-_SPACE_-_
  12pound := \#
  13
  14###
  15# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
  16dot-target = $(dir $@).$(notdir $@)
  17
  18###
  19# The temporary file to save gcc -MD generated dependencies must not
  20# contain a comma
  21depfile = $(subst $(comma),_,$(dot-target).d)
  22
  23###
  24# filename of target with directory and extension stripped
  25basetarget = $(basename $(notdir $@))
  26
  27###
  28# real prerequisites without phony targets
  29real-prereqs = $(filter-out $(PHONY), $^)
  30
  31###
  32# Escape single quote for use in echo statements
  33escsq = $(subst $(squote),'\$(squote)',$1)
  34
  35###
  36# Easy method for doing a status message
  37       kecho := :
  38 quiet_kecho := echo
  39silent_kecho := :
  40kecho := $($(quiet)kecho)
  41
  42###
  43# filechk is used to check if the content of a generated file is updated.
  44# Sample usage:
  45#
  46# filechk_sample = echo $(KERNELRELEASE)
  47# version.h: FORCE
  48#       $(call filechk,sample)
  49#
  50# The rule defined shall write to stdout the content of the new file.
  51# The existing file will be compared with the new one.
  52# - If no file exist it is created
  53# - If the content differ the new file is used
  54# - If they are equal no change, and no timestamp update
  55# - stdin is piped in from the first prerequisite ($<) so one has
  56#   to specify a valid file as first prerequisite (often the kbuild file)
  57define filechk
  58        $(Q)set -e;                             \
  59        mkdir -p $(dir $@);                     \
  60        { $(filechk_$(1)); } > $@.tmp;          \
  61        if [ -r $@ ] && cmp -s $@ $@.tmp; then  \
  62                rm -f $@.tmp;                   \
  63        else                                    \
  64                $(kecho) '  UPD     $@';        \
  65                mv -f $@.tmp $@;                \
  66        fi
  67endef
  68
  69######
  70# gcc support functions
  71# See documentation in Documentation/kbuild/makefiles.rst
  72
  73# cc-cross-prefix
  74# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
  75# Return first <prefix> where a <prefix>gcc is found in PATH.
  76# If no gcc found in PATH with listed prefixes return nothing
  77#
  78# Note: '2>/dev/null' is here to force Make to invoke a shell. Otherwise, it
  79# would try to directly execute the shell builtin 'command'. This workaround
  80# should be kept for a long time since this issue was fixed only after the
  81# GNU Make 4.2.1 release.
  82cc-cross-prefix = $(firstword $(foreach c, $(1), \
  83                        $(if $(shell command -v -- $(c)gcc 2>/dev/null), $(c))))
  84
  85# output directory for tests below
  86TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
  87
  88# try-run
  89# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
  90# Exit code chooses option. "$$TMP" serves as a temporary file and is
  91# automatically cleaned up.
  92try-run = $(shell set -e;               \
  93        TMP="$(TMPOUT).$$$$.tmp";       \
  94        TMPO="$(TMPOUT).$$$$.o";        \
  95        if ($(1)) >/dev/null 2>&1;      \
  96        then echo "$(2)";               \
  97        else echo "$(3)";               \
  98        fi;                             \
  99        rm -f "$$TMP" "$$TMPO")
 100
 101# as-option
 102# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
 103
 104as-option = $(call try-run,\
 105        $(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))
 106
 107# as-instr
 108# Usage: cflags-y += $(call as-instr,instr,option1,option2)
 109
 110as-instr = $(call try-run,\
 111        printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
 112
 113# __cc-option
 114# Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586)
 115__cc-option = $(call try-run,\
 116        $(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4))
 117
 118# Do not attempt to build with gcc plugins during cc-option tests.
 119# (And this uses delayed resolution so the flags will be up to date.)
 120CC_OPTION_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS))
 121
 122# cc-option
 123# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
 124
 125cc-option = $(call __cc-option, $(CC),\
 126        $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS),$(1),$(2))
 127
 128# cc-option-yn
 129# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
 130cc-option-yn = $(call try-run,\
 131        $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
 132
 133# cc-disable-warning
 134# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
 135cc-disable-warning = $(call try-run,\
 136        $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
 137
 138# cc-ifversion
 139# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
 140cc-ifversion = $(shell [ $(CONFIG_GCC_VERSION)0 $(1) $(2)000 ] && echo $(3) || echo $(4))
 141
 142# ld-option
 143# Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y)
 144ld-option = $(call try-run, $(LD) $(KBUILD_LDFLAGS) $(1) -v,$(1),$(2),$(3))
 145
 146# ar-option
 147# Usage: KBUILD_ARFLAGS := $(call ar-option,D)
 148# Important: no spaces around options
 149ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2))
 150
 151# ld-version
 152# Note this is mainly for HJ Lu's 3 number binutil versions
 153ld-version = $(shell $(LD) --version | $(srctree)/scripts/ld-version.sh)
 154
 155# ld-ifversion
 156# Usage:  $(call ld-ifversion, -ge, 22252, y)
 157ld-ifversion = $(shell [ $(ld-version) $(1) $(2) ] && echo $(3) || echo $(4))
 158
 159######
 160
 161###
 162# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
 163# Usage:
 164# $(Q)$(MAKE) $(build)=dir
 165build := -f $(srctree)/scripts/Makefile.build obj
 166
 167###
 168# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj=
 169# Usage:
 170# $(Q)$(MAKE) $(modbuiltin)=dir
 171modbuiltin := -f $(srctree)/scripts/Makefile.modbuiltin obj
 172
 173###
 174# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.dtbinst obj=
 175# Usage:
 176# $(Q)$(MAKE) $(dtbinst)=dir
 177dtbinst := -f $(srctree)/scripts/Makefile.dtbinst obj
 178
 179###
 180# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=
 181# Usage:
 182# $(Q)$(MAKE) $(clean)=dir
 183clean := -f $(srctree)/scripts/Makefile.clean obj
 184
 185# echo command.
 186# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
 187echo-cmd = $(if $($(quiet)cmd_$(1)),\
 188        echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
 189
 190# printing commands
 191cmd = @set -e; $(echo-cmd) $(cmd_$(1))
 192
 193###
 194# if_changed      - execute command if any prerequisite is newer than
 195#                   target, or command line has changed
 196# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
 197#                   including used config symbols
 198# if_changed_rule - as if_changed but execute rule instead
 199# See Documentation/kbuild/makefiles.rst for more info
 200
 201ifneq ($(KBUILD_NOCMDDEP),1)
 202# Check if both commands are the same including their order. Result is empty
 203# string if equal. User may override this check using make KBUILD_NOCMDDEP=1
 204cmd-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \
 205                         $(subst $(space),$(space_escape),$(strip $(cmd_$1))))
 206else
 207cmd-check = $(if $(strip $(cmd_$@)),,1)
 208endif
 209
 210# Replace >$< with >$$< to preserve $ when reloading the .cmd file
 211# (needed for make)
 212# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
 213# (needed for make)
 214# Replace >'< with >'\''< to be able to enclose the whole string in '...'
 215# (needed for the shell)
 216make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
 217
 218# Find any prerequisites that is newer than target or that does not exist.
 219# PHONY targets skipped in both cases.
 220any-prereq = $(filter-out $(PHONY),$?)$(filter-out $(PHONY) $(wildcard $^),$^)
 221
 222# Execute command if command has changed or prerequisite(s) are updated.
 223if_changed = $(if $(any-prereq)$(cmd-check),                                 \
 224        $(cmd);                                                              \
 225        printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
 226
 227# Execute the command and also postprocess generated .d dependencies file.
 228if_changed_dep = $(if $(any-prereq)$(cmd-check),$(cmd_and_fixdep),@:)
 229
 230cmd_and_fixdep =                                                             \
 231        $(cmd);                                                              \
 232        scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\
 233        rm -f $(depfile)
 234
 235# Usage: $(call if_changed_rule,foo)
 236# Will check if $(cmd_foo) or any of the prerequisites changed,
 237# and if so will execute $(rule_foo).
 238if_changed_rule = $(if $(any-prereq)$(cmd-check),$(rule_$(1)),@:)
 239
 240###
 241# why - tell why a target got built
 242#       enabled by make V=2
 243#       Output (listed in the order they are checked):
 244#          (1) - due to target is PHONY
 245#          (2) - due to target missing
 246#          (3) - due to: file1.h file2.h
 247#          (4) - due to command line change
 248#          (5) - due to missing .cmd file
 249#          (6) - due to target not in $(targets)
 250# (1) PHONY targets are always build
 251# (2) No target, so we better build it
 252# (3) Prerequisite is newer than target
 253# (4) The command line stored in the file named dir/.target.cmd
 254#     differed from actual command line. This happens when compiler
 255#     options changes
 256# (5) No dir/.target.cmd file (used to store command line)
 257# (6) No dir/.target.cmd file and target not listed in $(targets)
 258#     This is a good hint that there is a bug in the kbuild file
 259ifeq ($(KBUILD_VERBOSE),2)
 260why =                                                                        \
 261    $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
 262        $(if $(wildcard $@),                                                 \
 263            $(if $(any-prereq),- due to: $(any-prereq),                      \
 264                $(if $(cmd-check),                                           \
 265                    $(if $(cmd_$@),- due to command line change,             \
 266                        $(if $(filter $@, $(targets)),                       \
 267                            - due to missing .cmd file,                      \
 268                            - due to $(notdir $@) not in $$(targets)         \
 269                         )                                                   \
 270                     )                                                       \
 271                 )                                                           \
 272             ),                                                              \
 273             - due to target missing                                         \
 274         )                                                                   \
 275     )
 276
 277echo-why = $(call escsq, $(strip $(why)))
 278endif
 279
 280###############################################################################
 281#
 282# When a Kconfig string contains a filename, it is suitable for
 283# passing to shell commands. It is surrounded by double-quotes, and
 284# any double-quotes or backslashes within it are escaped by
 285# backslashes.
 286#
 287# This is no use for dependencies or $(wildcard). We need to strip the
 288# surrounding quotes and the escaping from quotes and backslashes, and
 289# we *do* need to escape any spaces in the string. So, for example:
 290#
 291# Usage: $(eval $(call config_filename,FOO))
 292#
 293# Defines FOO_FILENAME based on the contents of the CONFIG_FOO option,
 294# transformed as described above to be suitable for use within the
 295# makefile.
 296#
 297# Also, if the filename is a relative filename and exists in the source
 298# tree but not the build tree, define FOO_SRCPREFIX as $(srctree)/ to
 299# be prefixed to *both* command invocation and dependencies.
 300#
 301# Note: We also print the filenames in the quiet_cmd_foo text, and
 302# perhaps ought to have a version specially escaped for that purpose.
 303# But it's only cosmetic, and $(patsubst "%",%,$(CONFIG_FOO)) is good
 304# enough.  It'll strip the quotes in the common case where there's no
 305# space and it's a simple filename, and it'll retain the quotes when
 306# there's a space. There are some esoteric cases in which it'll print
 307# the wrong thing, but we don't really care. The actual dependencies
 308# and commands *do* get it right, with various combinations of single
 309# and double quotes, backslashes and spaces in the filenames.
 310#
 311###############################################################################
 312#
 313define config_filename
 314ifneq ($$(CONFIG_$(1)),"")
 315$(1)_FILENAME := $$(subst \\,\,$$(subst \$$(quote),$$(quote),$$(subst $$(space_escape),\$$(space),$$(patsubst "%",%,$$(subst $$(space),$$(space_escape),$$(CONFIG_$(1)))))))
 316ifneq ($$(patsubst /%,%,$$(firstword $$($(1)_FILENAME))),$$(firstword $$($(1)_FILENAME)))
 317else
 318ifeq ($$(wildcard $$($(1)_FILENAME)),)
 319ifneq ($$(wildcard $$(srctree)/$$($(1)_FILENAME)),)
 320$(1)_SRCPREFIX := $(srctree)/
 321endif
 322endif
 323endif
 324endif
 325endef
 326#
 327###############################################################################
 328
 329# delete partially updated (i.e. corrupted) files on error
 330.DELETE_ON_ERROR:
 331
 332# do not delete intermediate files automatically
 333.SECONDARY:
 334