LXR busybox/scripts/Kbuild.include

   1####
   2# kbuild: Generic definitions
   3
   4# Convinient variables
   5comma   := ,
   6squote  := '
   7empty   :=
   8space   := $(empty) $(empty)
   9
  10###
  11# The temporary file to save gcc -MD generated dependencies must not
  12# contain a comma
  13depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
  14
  15###
  16# Escape single quote for use in echo statements
  17escsq = $(subst $(squote),'\$(squote)',$1)
  18
  19###
  20# filechk is used to check if the content of a generated file is updated.
  21# Sample usage:
  22# define filechk_sample
  23#       echo $KERNELRELEASE
  24# endef
  25# version.h : Makefile
  26#       $(call filechk,sample)
  27# The rule defined shall write to stdout the content of the new file.
  28# The existing file will be compared with the new one.
  29# - If no file exist it is created
  30# - If the content differ the new file is used
  31# - If they are equal no change, and no timestamp update
  32# - stdin is piped in from the first prerequisite ($<) so one has
  33#   to specify a valid file as first prerequisite (often the kbuild file)
  34define filechk
  35        $(Q)set -e;                             \
  36        echo '  CHK     $@';                    \
  37        mkdir -p $(dir $@);                     \
  38        $(filechk_$(1)) < $< > $@.tmp;          \
  39        if [ -r $@ ] && cmp -s $@ $@.tmp; then  \
  40                rm -f $@.tmp;                   \
  41        else                                    \
  42                echo '  UPD     $@';            \
  43                mv -f $@.tmp $@;                \
  44        fi
  45endef
  46
  47######
  48# gcc support functions
  49# See documentation in Documentation/kbuild/makefiles.txt
  50
  51# as-option
  52# Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,)
  53
  54as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \
  55             -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \
  56             else echo "$(2)"; fi ;)
  57
  58# cc-option
  59# Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586)
  60
  61cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
  62             > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
  63
  64# hostcc-option
  65# Usage: hostcflags-y += $(call hostcc-option, -march=winchip-c6, -march=i586)
  66
  67hostcc-option = $(shell if $(HOSTCC) $(HOSTCFLAGS) $(1) -S -o /dev/null -xc /dev/null \
  68             > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
  69
  70# cc-option-yn
  71# Usage: flag := $(call cc-option-yn, -march=winchip-c6)
  72cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
  73                > /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
  74
  75# cc-option-align
  76# Prefix align with either -falign or -malign
  77cc-option-align = $(subst -functions=0,,\
  78        $(call cc-option,-falign-functions=0,-malign-functions=0))
  79
  80# cc-version
  81# Usage gcc-ver := $(call cc-version, $(CC))
  82cc-version = $(shell PATH="$(PATH)" $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh \
  83              $(if $(1), $(1), $(CC)))
  84
  85# cc-ifversion
  86# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
  87cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \
  88                       echo $(3); fi;)
  89
  90###
  91# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
  92# Usage:
  93# $(Q)$(MAKE) $(build)=dir
  94build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
  95
  96# Prefix -I with $(srctree) if it is not an absolute path
  97addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
  98# Find all -I options and call addtree
  99flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
 100
 101# If quiet is set, only print short version of command
 102cmd = @$(echo-cmd) $(cmd_$(1))
 103
 104# Add $(obj)/ for paths that is not absolute
 105objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
 106
 107###
 108# if_changed      - execute command if any prerequisite is newer than
 109#                   target, or command line has changed
 110# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
 111#                   including used config symbols
 112# if_changed_rule - as if_changed but execute rule instead
 113# See Documentation/kbuild/makefiles.txt for more info
 114
 115ifneq ($(KBUILD_NOCMDDEP),1)
 116# Check if both arguments has same arguments. Result in empty string if equal
 117# User may override this check using make KBUILD_NOCMDDEP=1
 118arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )
 119endif
 120
 121# echo command. Short version is $(quiet) equals quiet, otherwise full command
 122echo-cmd = $(if $($(quiet)cmd_$(1)), \
 123        echo '  $(call escsq,$($(quiet)cmd_$(1)))';)
 124
 125make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
 126
 127# function to only execute the passed command if necessary
 128# >'< substitution is for echo to work, >$< substitution to preserve $ when reloading .cmd file
 129# note: when using inline perl scripts [perl -e '...$$t=1;...'] in $(cmd_xxx) double $$ your perl vars
 130#
 131if_changed = $(if $(strip $(filter-out $(PHONY),$?)          \
 132                $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
 133        @set -e; \
 134        $(echo-cmd) $(cmd_$(1)); \
 135        echo 'cmd_$@ := $(make-cmd)' > $(@D)/.$(@F).cmd)
 136
 137# execute the command and also postprocess generated .d dependencies
 138# file
 139if_changed_dep = $(if $(strip $(filter-out $(PHONY),$?)  \
 140                $(filter-out FORCE $(wildcard $^),$^)    \
 141        $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),     \
 142        @set -e; \
 143        $(echo-cmd) $(cmd_$(1)); \
 144        scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(@D)/.$(@F).tmp; \
 145        rm -f $(depfile); \
 146        mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd)
 147
 148# Usage: $(call if_changed_rule,foo)
 149# will check if $(cmd_foo) changed, or any of the prequisites changed,
 150# and if so will execute $(rule_foo)
 151if_changed_rule = $(if $(strip $(filter-out $(PHONY),$?)            \
 152                        $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\
 153                        @set -e; \
 154                        $(rule_$(1)))
 155