1#### 2# kbuild: Generic definitions 3 4# Convinient variables 5comma := , 6squote := ' 7empty := 8space := $(empty) $(empty) 9 10### 11# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o 12dot-target = $(dir $@).$(notdir $@) 13 14### 15# The temporary file to save gcc -MD generated dependencies must not 16# contain a comma 17depfile = $(subst $(comma),_,$(dot-target).d) 18 19### 20# filename of target with directory and extension stripped 21basetarget = $(basename $(notdir $@)) 22 23### 24# Escape single quote for use in echo statements 25escsq = $(subst $(squote),'\$(squote)',$1) 26 27### 28# filechk is used to check if the content of a generated file is updated. 29# Sample usage: 30# define filechk_sample 31# echo $KERNELRELEASE 32# endef 33# version.h : Makefile 34# $(call filechk,sample) 35# The rule defined shall write to stdout the content of the new file. 36# The existing file will be compared with the new one. 37# - If no file exist it is created 38# - If the content differ the new file is used 39# - If they are equal no change, and no timestamp update 40# - stdin is piped in from the first prerequisite ($<) so one has 41# to specify a valid file as first prerequisite (often the kbuild file) 42define filechk 43 $(Q)set -e; \ 44 echo ' CHK $@'; \ 45 mkdir -p $(dir $@); \ 46 $(filechk_$(1)) < $< > $@.tmp; \ 47 if [ -r $@ ] && cmp -s $@ $@.tmp; then \ 48 rm -f $@.tmp; \ 49 else \ 50 echo ' UPD $@'; \ 51 mv -f $@.tmp $@; \ 52 fi 53endef 54 55###### 56# gcc support functions 57# See documentation in Documentation/kbuild/makefiles.txt 58 59# as-option 60# Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,) 61 62as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \ 63 -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \ 64 else echo "$(2)"; fi ;) 65 66# cc-option 67# Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586) 68 69cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \ 70 > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;) 71 72# cc-option-yn 73# Usage: flag := $(call cc-option-yn, -march=winchip-c6) 74cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \ 75 > /dev/null 2>&1; then echo "y"; else echo "n"; fi;) 76 77# cc-option-align 78# Prefix align with either -falign or -malign 79cc-option-align = $(subst -functions=0,,\ 80 $(call cc-option,-falign-functions=0,-malign-functions=0)) 81 82# cc-version 83# Usage gcc-ver := $(call cc-version, $(CC)) 84cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(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# ld-option 92# Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both) 93ld-option = $(shell if $(CC) $(1) \ 94 -nostdlib -o ldtest$$$$.out -xc /dev/null \ 95 > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi; \ 96 rm -f ldtest$$$$.out) 97 98### 99# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= 100# Usage: 101# $(Q)$(MAKE) $(build)=dir 102build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj 103 104# Prefix -I with $(srctree) if it is not an absolute path 105addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1) 106# Find all -I options and call addtree 107flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o))) 108 109# If quiet is set, only print short version of command 110cmd = @$(echo-cmd) $(cmd_$(1)) 111 112# Add $(obj)/ for paths that is not absolute 113objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o))) 114 115### 116# if_changed - execute command if any prerequisite is newer than 117# target, or command line has changed 118# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies 119# including used config symbols 120# if_changed_rule - as if_changed but execute rule instead 121# See Documentation/kbuild/makefiles.txt for more info 122 123ifneq ($(KBUILD_NOCMDDEP),1) 124# Check if both arguments has same arguments. Result in empty string if equal 125# User may override this check using make KBUILD_NOCMDDEP=1 126arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \ 127 $(filter-out $(cmd_$@), $(cmd_$(1))) ) 128endif 129 130# echo command. Short version is $(quiet) equals quiet, otherwise full command 131echo-cmd = $(if $($(quiet)cmd_$(1)), \ 132 echo ' $(call escsq,$($(quiet)cmd_$(1)))';) 133 134# >'< substitution is for echo to work, 135# >$< substitution to preserve $ when reloading .cmd file 136# note: when using inline perl scripts [perl -e '...$$t=1;...'] 137# in $(cmd_xxx) double $$ your perl vars 138make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1))))) 139 140# Find any prerequisites that is newer than target or that does not exist. 141# PHONY targets skipped in both cases. 142any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^) 143 144# Execute command if command has changed or prerequisitei(s) are updated 145# 146if_changed = $(if $(strip $(any-prereq) $(arg-check)), \ 147 @set -e; \ 148 $(echo-cmd) $(cmd_$(1)); \ 149 echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd) 150 151# execute the command and also postprocess generated .d dependencies 152# file 153if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \ 154 @set -e; \ 155 $(echo-cmd) $(cmd_$(1)); \ 156 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\ 157 rm -f $(depfile); \ 158 mv -f $(dot-target).tmp $(dot-target).cmd) 159 160# Usage: $(call if_changed_rule,foo) 161# will check if $(cmd_foo) changed, or any of the prequisites changed, 162# and if so will execute $(rule_foo) 163if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \ 164 @set -e; \ 165 $(rule_$(1))) 166 167