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