LXR busybox/scripts/Kbuild.include

   1####
   2# kbuild: Generic definitions
   3
   4# Convinient variables
   5comma   := ,
   6squote  := '
   7quote   := "
   8empty   :=
   9space   := $(empty) $(empty)
  10
  11###
  12# The temporary file to save gcc -MD generated dependencies must not
  13# contain a comma
  14depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
  15
  16###
  17# Escape single quote for use in echo statements
  18escsq = $(subst $(squote),'\$(squote)',$1)
  19
  20###
  21# filechk is used to check if the content of a generated file is updated.
  22# Sample usage:
  23# define filechk_sample
  24#       echo $KERNELRELEASE
  25# endef
  26# version.h : Makefile
  27#       $(call filechk,sample)
  28# The rule defined shall write to stdout the content of the new file.
  29# The existing file will be compared with the new one.
  30# - If no file exist it is created
  31# - If the content differ the new file is used
  32# - If they are equal no change, and no timestamp update
  33# - stdin is piped in from the first prerequisite ($<) so one has
  34#   to specify a valid file as first prerequisite (often the kbuild file)
  35define filechk
  36        $(Q)set -e;                             \
  37        echo '  CHK     $@';                    \
  38        mkdir -p $(dir $@);                     \
  39        $(filechk_$(1)) < $< > $@.tmp;          \
  40        if [ -r $@ ] && cmp -s $@ $@.tmp; then  \
  41                rm -f $@.tmp;                   \
  42        else                                    \
  43                echo '  UPD     $@';            \
  44                mv -f $@.tmp $@;                \
  45        fi
  46endef
  47
  48######
  49# gcc support functions
  50# See documentation in Documentation/kbuild/makefiles.txt
  51
  52# as-option
  53# Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,)
  54
  55as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \
  56             -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \
  57             else echo "$(2)"; fi ;)
  58
  59# cc-option
  60# Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586)
  61
  62cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
  63             > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
  64
  65# hostcc-option
  66# Usage: hostcflags-y += $(call hostcc-option, -march=winchip-c6, -march=i586)
  67
  68hostcc-option = $(shell if $(HOSTCC) $(HOSTCFLAGS) $(1) -S -o /dev/null -xc /dev/null \
  69             > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
  70
  71# cc-option-yn
  72# Usage: flag := $(call cc-option-yn, -march=winchip-c6)
  73cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
  74                > /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
  75
  76# cc-option-align
  77# Prefix align with either -falign or -malign
  78cc-option-align = $(subst -functions=0,,\
  79        $(call cc-option,-falign-functions=0,-malign-functions=0))
  80
  81# cc-version
  82# Usage gcc-ver := $(call cc-version, $(CC))
  83cc-version = $(shell PATH="$(PATH)" $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh \
  84              $(if $(1), $(1), $(CC)))
  85
  86# cc-ifversion
  87# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
  88cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \
  89                       echo $(3); fi;)
  90
  91###
  92# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
  93# Usage:
  94# $(Q)$(MAKE) $(build)=dir
  95build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
  96
  97# Prefix -I with $(srctree) if it is not an absolute path
  98addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
  99# Find all -I options and call addtree
 100flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
 101
 102# If quiet is set, only print short version of command
 103cmd = @$(echo-cmd) $(cmd_$(1))
 104
 105# Add $(obj)/ for paths that is not absolute
 106objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
 107
 108###
 109# if_changed      - execute command if any prerequisite is newer than
 110#                   target, or command line has changed
 111# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
 112#                   including used config symbols
 113# if_changed_rule - as if_changed but execute rule instead
 114# See Documentation/kbuild/makefiles.txt for more info
 115
 116ifneq ($(KBUILD_NOCMDDEP),1)
 117# Check if both arguments has same arguments. Result in empty string if equal
 118# User may override this check using make KBUILD_NOCMDDEP=1
 119arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )
 120endif
 121
 122# echo command. Short version is $(quiet) equals quiet, otherwise full command
 123echo-cmd = $(if $($(quiet)cmd_$(1)), \
 124        echo '  $(call escsq,$($(quiet)cmd_$(1)))';)
 125
 126make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
 127
 128# function to only execute the passed command if necessary
 129# >'< substitution is for echo to work, >$< substitution to preserve $ when reloading .cmd file
 130# note: when using inline perl scripts [perl -e '...$$t=1;...'] in $(cmd_xxx) double $$ your perl vars
 131#
 132if_changed = $(if $(strip $(filter-out $(PHONY),$?)          \
 133                $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
 134        @set -e; \
 135        $(echo-cmd) $(cmd_$(1)); \
 136        echo 'cmd_$@ := $(make-cmd)' > $(@D)/.$(@F).cmd)
 137
 138# execute the command and also postprocess generated .d dependencies
 139# file
 140if_changed_dep = $(if $(strip $(filter-out $(PHONY),$?)  \
 141                $(filter-out FORCE $(wildcard $^),$^)    \
 142        $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),     \
 143        @set -e; \
 144        $(echo-cmd) $(cmd_$(1)); \
 145        scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(@D)/.$(@F).tmp; \
 146        rm -f $(depfile); \
 147        mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd)
 148
 149# Usage: $(call if_changed_rule,foo)
 150# will check if $(cmd_foo) changed, or any of the prequisites changed,
 151# and if so will execute $(rule_foo)
 152if_changed_rule = $(if $(strip $(filter-out $(PHONY),$?)            \
 153                        $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\
 154                        @set -e; \
 155                        $(rule_$(1)))
 156