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