linux/scripts/Kbuild.include
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   1####
   2# kbuild: Generic definitions
   3
   4# Convenient variables
   5comma   := ,
   6quote   := "
   7squote  := '
   8empty   :=
   9space   := $(empty) $(empty)
  10space_escape := _-_SPACE_-_
  11right_paren := )
  12left_paren := (
  13pound := \#
  14
  15###
  16# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
  17dot-target = $(dir $@).$(notdir $@)
  18
  19###
  20# The temporary file to save gcc -MD generated dependencies must not
  21# contain a comma
  22depfile = $(subst $(comma),_,$(dot-target).d)
  23
  24###
  25# filename of target with directory and extension stripped
  26basetarget = $(basename $(notdir $@))
  27
  28###
  29# filename of first prerequisite with directory and extension stripped
  30baseprereq = $(basename $(notdir $<))
  31
  32###
  33# Escape single quote for use in echo statements
  34escsq = $(subst $(squote),'\$(squote)',$1)
  35
  36###
  37# Easy method for doing a status message
  38       kecho := :
  39 quiet_kecho := echo
  40silent_kecho := :
  41kecho := $($(quiet)kecho)
  42
  43###
  44# filechk is used to check if the content of a generated file is updated.
  45# Sample usage:
  46# define filechk_sample
  47#       echo $KERNELRELEASE
  48# endef
  49# version.h : Makefile
  50#       $(call filechk,sample)
  51# The rule defined shall write to stdout the content of the new file.
  52# The existing file will be compared with the new one.
  53# - If no file exist it is created
  54# - If the content differ the new file is used
  55# - If they are equal no change, and no timestamp update
  56# - stdin is piped in from the first prerequisite ($<) so one has
  57#   to specify a valid file as first prerequisite (often the kbuild file)
  58define filechk
  59        $(Q)set -e;                             \
  60        $(kecho) '  CHK     $@';                \
  61        mkdir -p $(dir $@);                     \
  62        $(filechk_$(1)) < $< > $@.tmp;          \
  63        if [ -r $@ ] && cmp -s $@ $@.tmp; then  \
  64                rm -f $@.tmp;                   \
  65        else                                    \
  66                $(kecho) '  UPD     $@';        \
  67                mv -f $@.tmp $@;                \
  68        fi
  69endef
  70
  71######
  72# gcc support functions
  73# See documentation in Documentation/kbuild/makefiles.txt
  74
  75# cc-cross-prefix
  76# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
  77# Return first prefix where a prefix$(CC) is found in PATH.
  78# If no $(CC) found in PATH with listed prefixes return nothing
  79cc-cross-prefix =  \
  80        $(word 1, $(foreach c,$(1),                                   \
  81                $(shell set -e;                                       \
  82                if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \
  83                        echo $(c);                                    \
  84                fi)))
  85
  86# Tools for caching Makefile variables that are "expensive" to compute.
  87#
  88# Here we want to help deal with variables that take a long time to compute
  89# by making it easy to store these variables in a cache.
  90#
  91# The canonical example here is testing for compiler flags.  On a simple system
  92# each call to the compiler takes 10 ms, but on a system with a compiler that's
  93# called through various wrappers it can take upwards of 100 ms.  If we have
  94# 100 calls to the compiler this can take 1 second (on a simple system) or 10
  95# seconds (on a complicated system).
  96#
  97# The "cache" will be in Makefile syntax and can be directly included.
  98# Any time we try to reference a variable that's not in the cache we'll
  99# calculate it and store it in the cache for next time.
 100
 101# Include values from last time
 102make-cache := $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/,$(if $(obj),$(obj)/)).cache.mk
 103$(make-cache): ;
 104-include $(make-cache)
 105
 106cached-data := $(filter __cached_%, $(.VARIABLES))
 107
 108# If cache exceeds 1000 lines, shrink it down to 500.
 109ifneq ($(word 1000,$(cached-data)),)
 110$(shell tail -n 500 $(make-cache) > $(make-cache).tmp; \
 111        mv $(make-cache).tmp $(make-cache))
 112endif
 113
 114create-cache-dir := $(if $(KBUILD_SRC),$(if $(cache-data),,1))
 115
 116# Usage: $(call __sanitize-opt,Hello=Hola$(comma)Goodbye Adios)
 117#
 118# Convert all '$', ')', '(', '\', '=', ' ', ',', ':' to '_'
 119__sanitize-opt = $(subst $$,_,$(subst $(right_paren),_,$(subst $(left_paren),_,$(subst \,_,$(subst =,_,$(subst $(space),_,$(subst $(comma),_,$(subst :,_,$(1)))))))))
 120
 121# Usage:   $(call shell-cached,shell_command)
 122# Example: $(call shell-cached,md5sum /usr/bin/gcc)
 123#
 124# If we've already seen a call to this exact shell command (even in a
 125# previous invocation of make!) we'll return the value.  If not, we'll
 126# compute it and store the result for future runs.
 127#
 128# This is a bit of voodoo, but basic explanation is that if the variable
 129# was undefined then we'll evaluate the shell command and store the result
 130# into the variable.  We'll then store that value in the cache and finally
 131# output the value.
 132#
 133# NOTE: The $$(2) here isn't actually a parameter to __run-and-store.  We
 134# happen to know that the caller will have their shell command in $(2) so the
 135# result of "call"ing this will produce a reference to that $(2).  The reason
 136# for this strangeness is to avoid an extra level of eval (and escaping) of
 137# $(2).
 138define __run-and-store
 139ifeq ($(origin $(1)),undefined)
 140  $$(eval $(1) := $$(shell $$(2)))
 141ifeq ($(create-cache-dir),1)
 142  $$(shell mkdir -p $(dir $(make-cache)))
 143  $$(eval create-cache-dir :=)
 144endif
 145  $$(shell echo '$(1) := $$($(1))' >> $(make-cache))
 146endif
 147endef
 148__shell-cached = $(eval $(call __run-and-store,$(1)))$($(1))
 149shell-cached = $(call __shell-cached,__cached_$(call __sanitize-opt,$(1)),$(1))
 150
 151# output directory for tests below
 152TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
 153
 154# try-run
 155# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
 156# Exit code chooses option. "$$TMP" serves as a temporary file and is
 157# automatically cleaned up.
 158__try-run = set -e;                     \
 159        TMP="$(TMPOUT).$$$$.tmp";       \
 160        TMPO="$(TMPOUT).$$$$.o";        \
 161        if ($(1)) >/dev/null 2>&1;      \
 162        then echo "$(2)";               \
 163        else echo "$(3)";               \
 164        fi;                             \
 165        rm -f "$$TMP" "$$TMPO"
 166
 167try-run = $(shell $(__try-run))
 168
 169# try-run-cached
 170# This works like try-run, but the result is cached.
 171try-run-cached = $(call shell-cached,$(__try-run))
 172
 173# as-option
 174# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
 175
 176as-option = $(call try-run-cached,\
 177        $(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))
 178
 179# as-instr
 180# Usage: cflags-y += $(call as-instr,instr,option1,option2)
 181
 182as-instr = $(call try-run-cached,\
 183        printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
 184
 185# __cc-option
 186# Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586)
 187__cc-option = $(call try-run-cached,\
 188        $(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4))
 189
 190# Do not attempt to build with gcc plugins during cc-option tests.
 191# (And this uses delayed resolution so the flags will be up to date.)
 192CC_OPTION_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS))
 193
 194# cc-option
 195# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
 196
 197cc-option = $(call __cc-option, $(CC),\
 198        $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS),$(1),$(2))
 199
 200# hostcc-option
 201# Usage: cflags-y += $(call hostcc-option,-march=winchip-c6,-march=i586)
 202hostcc-option = $(call __cc-option, $(HOSTCC),\
 203        $(HOSTCFLAGS) $(HOST_EXTRACFLAGS),$(1),$(2))
 204
 205# cc-option-yn
 206# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
 207cc-option-yn = $(call try-run-cached,\
 208        $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
 209
 210# cc-disable-warning
 211# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
 212cc-disable-warning = $(call try-run-cached,\
 213        $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
 214
 215# cc-name
 216# Expands to either gcc or clang
 217cc-name = $(call shell-cached,$(CC) -v 2>&1 | grep -q "clang version" && echo clang || echo gcc)
 218
 219# cc-version
 220cc-version = $(call shell-cached,$(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
 221
 222# cc-fullversion
 223cc-fullversion = $(call shell-cached,$(CONFIG_SHELL) \
 224        $(srctree)/scripts/gcc-version.sh -p $(CC))
 225
 226# cc-ifversion
 227# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
 228cc-ifversion = $(shell [ $(cc-version) $(1) $(2) ] && echo $(3) || echo $(4))
 229
 230# cc-if-fullversion
 231# Usage:  EXTRA_CFLAGS += $(call cc-if-fullversion, -lt, 040502, -O1)
 232cc-if-fullversion = $(shell [ $(cc-fullversion) $(1) $(2) ] && echo $(3) || echo $(4))
 233
 234# cc-ldoption
 235# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
 236cc-ldoption = $(call try-run-cached,\
 237        $(CC) $(1) $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))
 238
 239# ld-option
 240# Usage: LDFLAGS += $(call ld-option, -X)
 241ld-option = $(call try-run-cached, $(LD) $(LDFLAGS) $(1) -v,$(1),$(2))
 242
 243# ar-option
 244# Usage: KBUILD_ARFLAGS := $(call ar-option,D)
 245# Important: no spaces around options
 246ar-option = $(call try-run-cached, $(AR) rc$(1) "$$TMP",$(1),$(2))
 247
 248# ld-version
 249# Note this is mainly for HJ Lu's 3 number binutil versions
 250ld-version = $(call shell-cached,$(LD) --version | $(srctree)/scripts/ld-version.sh)
 251
 252# ld-ifversion
 253# Usage:  $(call ld-ifversion, -ge, 22252, y)
 254ld-ifversion = $(shell [ $(ld-version) $(1) $(2) ] && echo $(3) || echo $(4))
 255
 256######
 257
 258###
 259# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
 260# Usage:
 261# $(Q)$(MAKE) $(build)=dir
 262build := -f $(srctree)/scripts/Makefile.build obj
 263
 264###
 265# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj=
 266# Usage:
 267# $(Q)$(MAKE) $(modbuiltin)=dir
 268modbuiltin := -f $(srctree)/scripts/Makefile.modbuiltin obj
 269
 270###
 271# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.dtbinst obj=
 272# Usage:
 273# $(Q)$(MAKE) $(dtbinst)=dir
 274dtbinst := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.dtbinst obj
 275
 276###
 277# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=
 278# Usage:
 279# $(Q)$(MAKE) $(clean)=dir
 280clean := -f $(srctree)/scripts/Makefile.clean obj
 281
 282###
 283# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.headersinst obj=
 284# Usage:
 285# $(Q)$(MAKE) $(hdr-inst)=dir
 286hdr-inst := -f $(srctree)/scripts/Makefile.headersinst obj
 287
 288# Prefix -I with $(srctree) if it is not an absolute path.
 289# skip if -I has no parameter
 290addtree = $(if $(patsubst -I%,%,$(1)), \
 291$(if $(filter-out -I/% -I./% -I../%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1)),$(1)))
 292
 293# Find all -I options and call addtree
 294flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
 295
 296# echo command.
 297# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
 298echo-cmd = $(if $($(quiet)cmd_$(1)),\
 299        echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
 300
 301# printing commands
 302cmd = @$(echo-cmd) $(cmd_$(1))
 303
 304# Add $(obj)/ for paths that are not absolute
 305objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
 306
 307###
 308# if_changed      - execute command if any prerequisite is newer than
 309#                   target, or command line has changed
 310# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
 311#                   including used config symbols
 312# if_changed_rule - as if_changed but execute rule instead
 313# See Documentation/kbuild/makefiles.txt for more info
 314
 315ifneq ($(KBUILD_NOCMDDEP),1)
 316# Check if both arguments are the same including their order. Result is empty
 317# string if equal. User may override this check using make KBUILD_NOCMDDEP=1
 318arg-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \
 319                         $(subst $(space),$(space_escape),$(strip $(cmd_$1))))
 320else
 321arg-check = $(if $(strip $(cmd_$@)),,1)
 322endif
 323
 324# Replace >$< with >$$< to preserve $ when reloading the .cmd file
 325# (needed for make)
 326# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
 327# (needed for make)
 328# Replace >'< with >'\''< to be able to enclose the whole string in '...'
 329# (needed for the shell)
 330make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
 331
 332# Find any prerequisites that is newer than target or that does not exist.
 333# PHONY targets skipped in both cases.
 334any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
 335
 336# Execute command if command has changed or prerequisite(s) are updated.
 337if_changed = $(if $(strip $(any-prereq) $(arg-check)),                       \
 338        @set -e;                                                             \
 339        $(echo-cmd) $(cmd_$(1));                                             \
 340        printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
 341
 342# Execute the command and also postprocess generated .d dependencies file.
 343if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ),                  \
 344        @set -e;                                                             \
 345        $(cmd_and_fixdep), @:)
 346
 347ifndef CONFIG_TRIM_UNUSED_KSYMS
 348
 349cmd_and_fixdep =                                                             \
 350        $(echo-cmd) $(cmd_$(1));                                             \
 351        scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
 352        rm -f $(depfile);                                                    \
 353        mv -f $(dot-target).tmp $(dot-target).cmd;
 354
 355else
 356
 357# Filter out exported kernel symbol names from the preprocessor output.
 358# See also __KSYM_DEPS__ in include/linux/export.h.
 359# We disable the depfile generation here, so as not to overwrite the existing
 360# depfile while fixdep is parsing it.
 361flags_nodeps = $(filter-out -Wp$(comma)-M%, $($(1)))
 362ksym_dep_filter =                                                            \
 363        case "$(1)" in                                                       \
 364          cc_*_c|cpp_i_c)                                                    \
 365            $(CPP) $(call flags_nodeps,c_flags) -D__KSYM_DEPS__ $< ;;        \
 366          as_*_S|cpp_s_S)                                                    \
 367            $(CPP) $(call flags_nodeps,a_flags) -D__KSYM_DEPS__ $< ;;        \
 368          boot*|build*|cpp_its_S|*cpp_lds_S|dtc|host*|vdso*) : ;;            \
 369          *) echo "Don't know how to preprocess $(1)" >&2; false ;;          \
 370        esac | tr ";" "\n" | sed -n 's/^.*=== __KSYM_\(.*\) ===.*$$/_\1/p'
 371
 372cmd_and_fixdep =                                                             \
 373        $(echo-cmd) $(cmd_$(1));                                             \
 374        $(ksym_dep_filter) |                                                 \
 375                scripts/basic/fixdep -e $(depfile) $@ '$(make-cmd)'          \
 376                        > $(dot-target).tmp;                                 \
 377        rm -f $(depfile);                                                    \
 378        mv -f $(dot-target).tmp $(dot-target).cmd;
 379
 380endif
 381
 382# Usage: $(call if_changed_rule,foo)
 383# Will check if $(cmd_foo) or any of the prerequisites changed,
 384# and if so will execute $(rule_foo).
 385if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ),                 \
 386        @set -e;                                                             \
 387        $(rule_$(1)), @:)
 388
 389###
 390# why - tell why a target got built
 391#       enabled by make V=2
 392#       Output (listed in the order they are checked):
 393#          (1) - due to target is PHONY
 394#          (2) - due to target missing
 395#          (3) - due to: file1.h file2.h
 396#          (4) - due to command line change
 397#          (5) - due to missing .cmd file
 398#          (6) - due to target not in $(targets)
 399# (1) PHONY targets are always build
 400# (2) No target, so we better build it
 401# (3) Prerequisite is newer than target
 402# (4) The command line stored in the file named dir/.target.cmd
 403#     differed from actual command line. This happens when compiler
 404#     options changes
 405# (5) No dir/.target.cmd file (used to store command line)
 406# (6) No dir/.target.cmd file and target not listed in $(targets)
 407#     This is a good hint that there is a bug in the kbuild file
 408ifeq ($(KBUILD_VERBOSE),2)
 409why =                                                                        \
 410    $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
 411        $(if $(wildcard $@),                                                 \
 412            $(if $(strip $(any-prereq)),- due to: $(any-prereq),             \
 413                $(if $(arg-check),                                           \
 414                    $(if $(cmd_$@),- due to command line change,             \
 415                        $(if $(filter $@, $(targets)),                       \
 416                            - due to missing .cmd file,                      \
 417                            - due to $(notdir $@) not in $$(targets)         \
 418                         )                                                   \
 419                     )                                                       \
 420                 )                                                           \
 421             ),                                                              \
 422             - due to target missing                                         \
 423         )                                                                   \
 424     )
 425
 426echo-why = $(call escsq, $(strip $(why)))
 427endif
 428
 429###############################################################################
 430#
 431# When a Kconfig string contains a filename, it is suitable for
 432# passing to shell commands. It is surrounded by double-quotes, and
 433# any double-quotes or backslashes within it are escaped by
 434# backslashes.
 435#
 436# This is no use for dependencies or $(wildcard). We need to strip the
 437# surrounding quotes and the escaping from quotes and backslashes, and
 438# we *do* need to escape any spaces in the string. So, for example:
 439#
 440# Usage: $(eval $(call config_filename,FOO))
 441#
 442# Defines FOO_FILENAME based on the contents of the CONFIG_FOO option,
 443# transformed as described above to be suitable for use within the
 444# makefile.
 445#
 446# Also, if the filename is a relative filename and exists in the source
 447# tree but not the build tree, define FOO_SRCPREFIX as $(srctree)/ to
 448# be prefixed to *both* command invocation and dependencies.
 449#
 450# Note: We also print the filenames in the quiet_cmd_foo text, and
 451# perhaps ought to have a version specially escaped for that purpose.
 452# But it's only cosmetic, and $(patsubst "%",%,$(CONFIG_FOO)) is good
 453# enough.  It'll strip the quotes in the common case where there's no
 454# space and it's a simple filename, and it'll retain the quotes when
 455# there's a space. There are some esoteric cases in which it'll print
 456# the wrong thing, but we don't really care. The actual dependencies
 457# and commands *do* get it right, with various combinations of single
 458# and double quotes, backslashes and spaces in the filenames.
 459#
 460###############################################################################
 461#
 462define config_filename
 463ifneq ($$(CONFIG_$(1)),"")
 464$(1)_FILENAME := $$(subst \\,\,$$(subst \$$(quote),$$(quote),$$(subst $$(space_escape),\$$(space),$$(patsubst "%",%,$$(subst $$(space),$$(space_escape),$$(CONFIG_$(1)))))))
 465ifneq ($$(patsubst /%,%,$$(firstword $$($(1)_FILENAME))),$$(firstword $$($(1)_FILENAME)))
 466else
 467ifeq ($$(wildcard $$($(1)_FILENAME)),)
 468ifneq ($$(wildcard $$(srctree)/$$($(1)_FILENAME)),)
 469$(1)_SRCPREFIX := $(srctree)/
 470endif
 471endif
 472endif
 473endif
 474endef
 475#
 476###############################################################################
 477