linux/scripts/Kbuild.include
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   1####
   2# kbuild: Generic definitions
   3
   4# Convenient variables
   5comma   := ,
   6squote  := '
   7empty   :=
   8space   := $(empty) $(empty)
   9
  10###
  11# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
  12dot-target = $(dir $@).$(notdir $@)
  13
  14###
  15# The temporary file to save gcc -MD generated dependencies must not
  16# contain a comma
  17depfile = $(subst $(comma),_,$(dot-target).d)
  18
  19###
  20# filename of target with directory and extension stripped
  21basetarget = $(basename $(notdir $@))
  22
  23###
  24# filename of first prerequisite with directory and extension stripped
  25baseprereq = $(basename $(notdir $<))
  26
  27###
  28# Escape single quote for use in echo statements
  29escsq = $(subst $(squote),'\$(squote)',$1)
  30
  31###
  32# Easy method for doing a status message
  33       kecho := :
  34 quiet_kecho := echo
  35silent_kecho := :
  36kecho := $($(quiet)kecho)
  37
  38###
  39# filechk is used to check if the content of a generated file is updated.
  40# Sample usage:
  41# define filechk_sample
  42#       echo $KERNELRELEASE
  43# endef
  44# version.h : Makefile
  45#       $(call filechk,sample)
  46# The rule defined shall write to stdout the content of the new file.
  47# The existing file will be compared with the new one.
  48# - If no file exist it is created
  49# - If the content differ the new file is used
  50# - If they are equal no change, and no timestamp update
  51# - stdin is piped in from the first prerequisite ($<) so one has
  52#   to specify a valid file as first prerequisite (often the kbuild file)
  53define filechk
  54        $(Q)set -e;                             \
  55        $(kecho) '  CHK     $@';                \
  56        mkdir -p $(dir $@);                     \
  57        $(filechk_$(1)) < $< > $@.tmp;          \
  58        if [ -r $@ ] && cmp -s $@ $@.tmp; then  \
  59                rm -f $@.tmp;                   \
  60        else                                    \
  61                $(kecho) '  UPD     $@';        \
  62                mv -f $@.tmp $@;                \
  63        fi
  64endef
  65
  66######
  67# gcc support functions
  68# See documentation in Documentation/kbuild/makefiles.txt
  69
  70# cc-cross-prefix
  71# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
  72# Return first prefix where a prefix$(CC) is found in PATH.
  73# If no $(CC) found in PATH with listed prefixes return nothing
  74cc-cross-prefix =  \
  75        $(word 1, $(foreach c,$(1),                                   \
  76                $(shell set -e;                                       \
  77                if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \
  78                        echo $(c);                                    \
  79                fi)))
  80
  81# output directory for tests below
  82TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
  83
  84# try-run
  85# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
  86# Exit code chooses option. "$$TMP" is can be used as temporary file and
  87# is automatically cleaned up.
  88try-run = $(shell set -e;               \
  89        TMP="$(TMPOUT).$$$$.tmp";       \
  90        TMPO="$(TMPOUT).$$$$.o";        \
  91        if ($(1)) >/dev/null 2>&1;      \
  92        then echo "$(2)";               \
  93        else echo "$(3)";               \
  94        fi;                             \
  95        rm -f "$$TMP" "$$TMPO")
  96
  97# as-option
  98# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
  99
 100as-option = $(call try-run,\
 101        $(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2))
 102
 103# as-instr
 104# Usage: cflags-y += $(call as-instr,instr,option1,option2)
 105
 106as-instr = $(call try-run,\
 107        printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
 108
 109# cc-option
 110# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
 111
 112cc-option = $(call try-run,\
 113        $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
 114
 115# cc-option-yn
 116# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
 117cc-option-yn = $(call try-run,\
 118        $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
 119
 120# cc-option-align
 121# Prefix align with either -falign or -malign
 122cc-option-align = $(subst -functions=0,,\
 123        $(call cc-option,-falign-functions=0,-malign-functions=0))
 124
 125# cc-disable-warning
 126# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
 127cc-disable-warning = $(call try-run,\
 128        $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
 129
 130# cc-version
 131# Usage gcc-ver := $(call cc-version)
 132cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
 133
 134# cc-fullversion
 135# Usage gcc-ver := $(call cc-fullversion)
 136cc-fullversion = $(shell $(CONFIG_SHELL) \
 137        $(srctree)/scripts/gcc-version.sh -p $(CC))
 138
 139# cc-ifversion
 140# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
 141cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
 142
 143# cc-ldoption
 144# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
 145cc-ldoption = $(call try-run,\
 146        $(CC) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))
 147
 148# ld-option
 149# Usage: LDFLAGS += $(call ld-option, -X)
 150ld-option = $(call try-run,\
 151        $(CC) -x c /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
 152
 153# ar-option
 154# Usage: KBUILD_ARFLAGS := $(call ar-option,D)
 155# Important: no spaces around options
 156ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2))
 157
 158######
 159
 160###
 161# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
 162# Usage:
 163# $(Q)$(MAKE) $(build)=dir
 164build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
 165
 166###
 167# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj=
 168# Usage:
 169# $(Q)$(MAKE) $(modbuiltin)=dir
 170modbuiltin := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.modbuiltin obj
 171
 172# Prefix -I with $(srctree) if it is not an absolute path.
 173# skip if -I has no parameter
 174addtree = $(if $(patsubst -I%,%,$(1)), \
 175$(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1))
 176
 177# Find all -I options and call addtree
 178flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
 179
 180# echo command.
 181# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
 182echo-cmd = $(if $($(quiet)cmd_$(1)),\
 183        echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
 184
 185# printing commands
 186cmd = @$(echo-cmd) $(cmd_$(1))
 187
 188# Add $(obj)/ for paths that are not absolute
 189objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
 190
 191###
 192# if_changed      - execute command if any prerequisite is newer than
 193#                   target, or command line has changed
 194# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
 195#                   including used config symbols
 196# if_changed_rule - as if_changed but execute rule instead
 197# See Documentation/kbuild/makefiles.txt for more info
 198
 199ifneq ($(KBUILD_NOCMDDEP),1)
 200# Check if both arguments has same arguments. Result is empty string if equal.
 201# User may override this check using make KBUILD_NOCMDDEP=1
 202arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
 203                    $(filter-out $(cmd_$@),   $(cmd_$(1))) )
 204else
 205arg-check = $(if $(strip $(cmd_$@)),,1)
 206endif
 207
 208# >'< substitution is for echo to work,
 209# >$< substitution to preserve $ when reloading .cmd file
 210# note: when using inline perl scripts [perl -e '...$$t=1;...']
 211# in $(cmd_xxx) double $$ your perl vars
 212make-cmd = $(subst \\,\\\\,$(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1))))))
 213
 214# Find any prerequisites that is newer than target or that does not exist.
 215# PHONY targets skipped in both cases.
 216any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
 217
 218# Execute command if command has changed or prerequisite(s) are updated.
 219#
 220if_changed = $(if $(strip $(any-prereq) $(arg-check)),                       \
 221        @set -e;                                                             \
 222        $(echo-cmd) $(cmd_$(1));                                             \
 223        echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
 224
 225# Execute the command and also postprocess generated .d dependencies file.
 226if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ),                  \
 227        @set -e;                                                             \
 228        $(echo-cmd) $(cmd_$(1));                                             \
 229        scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
 230        rm -f $(depfile);                                                    \
 231        mv -f $(dot-target).tmp $(dot-target).cmd)
 232
 233# Usage: $(call if_changed_rule,foo)
 234# Will check if $(cmd_foo) or any of the prerequisites changed,
 235# and if so will execute $(rule_foo).
 236if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ),                 \
 237        @set -e;                                                             \
 238        $(rule_$(1)))
 239
 240###
 241# why - tell why a a target got build
 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 $(strip $(any-prereq)),- due to: $(any-prereq),             \
 264                $(if $(arg-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
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