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 $(CC)) 81 82# cc-ifversion 83# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1) 84cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \ 85 echo $(3); fi;) 86 87# ld-option 88# Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both) 89ld-option = $(shell if $(CC) $(1) \ 90 -nostdlib -o ldtest$$$$.out -xc /dev/null \ 91 > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi; \ 92 rm -f ldtest$$$$.out) 93 94### 95# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= 96# Usage: 97# $(Q)$(MAKE) $(build)=dir 98build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj 99 100# Prefix -I with $(srctree) if it is not an absolute path 101addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1) 102# Find all -I options and call addtree 103flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o))) 104 105# If quiet is set, only print short version of command 106cmd = @$(echo-cmd) $(cmd_$(1)) 107 108# Add $(obj)/ for paths that is not absolute 109objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o))) 110 111### 112# if_changed - execute command if any prerequisite is newer than 113# target, or command line has changed 114# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies 115# including used config symbols 116# if_changed_rule - as if_changed but execute rule instead 117# See Documentation/kbuild/makefiles.txt for more info 118 119ifneq ($(KBUILD_NOCMDDEP),1) 120# Check if both arguments has same arguments. Result in empty string if equal 121# User may override this check using make KBUILD_NOCMDDEP=1 122arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) ) 123endif 124 125# echo command. Short version is $(quiet) equals quiet, otherwise full command 126echo-cmd = $(if $($(quiet)cmd_$(1)), \ 127 echo ' $(call escsq,$($(quiet)cmd_$(1)))';) 128 129make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1))))) 130 131# function to only execute the passed command if necessary 132# >'< substitution is for echo to work, >$< substitution to preserve $ when reloading .cmd file 133# note: when using inline perl scripts [perl -e '...$$t=1;...'] in $(cmd_xxx) double $$ your perl vars 134# 135if_changed = $(if $(strip $(filter-out $(PHONY),$?) \ 136 $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \ 137 @set -e; \ 138 $(echo-cmd) $(cmd_$(1)); \ 139 echo 'cmd_$@ := $(make-cmd)' > $(@D)/.$(@F).cmd) 140 141# execute the command and also postprocess generated .d dependencies 142# file 143if_changed_dep = $(if $(strip $(filter-out $(PHONY),$?) \ 144 $(filter-out FORCE $(wildcard $^),$^) \ 145 $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \ 146 @set -e; \ 147 $(echo-cmd) $(cmd_$(1)); \ 148 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(@D)/.$(@F).tmp; \ 149 rm -f $(depfile); \ 150 mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd) 151 152# Usage: $(call if_changed_rule,foo) 153# will check if $(cmd_foo) changed, or any of the prequisites changed, 154# and if so will execute $(rule_foo) 155if_changed_rule = $(if $(strip $(filter-out $(PHONY),$?) \ 156 $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\ 157 @set -e; \ 158 $(rule_$(1))) 159