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# output directory for tests below 60TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/) 61 62# as-option 63# Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,) 64 65as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \ 66 -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \ 67 else echo "$(2)"; fi ;) 68 69# as-instr 70# Usage: cflags-y += $(call as-instr, instr, option1, option2) 71 72as-instr = $(shell if echo -e "$(1)" | \ 73 $(CC) $(AFLAGS) -c -xassembler - \ 74 -o $(TMPOUT)astest$$$$.out > /dev/null 2>&1; \ 75 then rm $(TMPOUT)astest$$$$.out; echo "$(2)"; \ 76 else echo "$(3)"; fi) 77 78# cc-option 79# Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586) 80 81cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \ 82 > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;) 83 84# cc-option-yn 85# Usage: flag := $(call cc-option-yn, -march=winchip-c6) 86cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \ 87 > /dev/null 2>&1; then echo "y"; else echo "n"; fi;) 88 89# cc-option-align 90# Prefix align with either -falign or -malign 91cc-option-align = $(subst -functions=0,,\ 92 $(call cc-option,-falign-functions=0,-malign-functions=0)) 93 94# cc-version 95# Usage gcc-ver := $(call cc-version, $(CC)) 96cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC)) 97 98# cc-ifversion 99# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1) 100cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \ 101 echo $(3); fi;) 102 103# ld-option 104# Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both) 105ld-option = $(shell if $(CC) $(1) -nostdlib -xc /dev/null \ 106 -o $(TMPOUT)ldtest$$$$.out > /dev/null 2>&1; \ 107 then rm $(TMPOUT)ldtest$$$$.out; echo "$(1)"; \ 108 else echo "$(2)"; fi) 109 110### 111# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= 112# Usage: 113# $(Q)$(MAKE) $(build)=dir 114build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj 115 116# Prefix -I with $(srctree) if it is not an absolute path 117addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1) 118# Find all -I options and call addtree 119flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o))) 120 121# If quiet is set, only print short version of command 122cmd = @$(echo-cmd) $(cmd_$(1)) 123 124# Add $(obj)/ for paths that is not absolute 125objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o))) 126 127### 128# if_changed - execute command if any prerequisite is newer than 129# target, or command line has changed 130# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies 131# including used config symbols 132# if_changed_rule - as if_changed but execute rule instead 133# See Documentation/kbuild/makefiles.txt for more info 134 135ifneq ($(KBUILD_NOCMDDEP),1) 136# Check if both arguments has same arguments. Result in empty string if equal 137# User may override this check using make KBUILD_NOCMDDEP=1 138arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \ 139 $(filter-out $(cmd_$@), $(cmd_$(1))) ) 140endif 141 142# echo command. Short version is $(quiet) equals quiet, otherwise full command 143echo-cmd = $(if $($(quiet)cmd_$(1)), \ 144 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';) 145 146# >'< substitution is for echo to work, 147# >$< substitution to preserve $ when reloading .cmd file 148# note: when using inline perl scripts [perl -e '...$$t=1;...'] 149# in $(cmd_xxx) double $$ your perl vars 150make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1))))) 151 152# Find any prerequisites that is newer than target or that does not exist. 153# PHONY targets skipped in both cases. 154any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^) 155 156# Execute command if command has changed or prerequisitei(s) are updated 157# 158if_changed = $(if $(strip $(any-prereq) $(arg-check)), \ 159 @set -e; \ 160 $(echo-cmd) $(cmd_$(1)); \ 161 echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd) 162 163# execute the command and also postprocess generated .d dependencies 164# file 165if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \ 166 @set -e; \ 167 $(echo-cmd) $(cmd_$(1)); \ 168 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\ 169 rm -f $(depfile); \ 170 mv -f $(dot-target).tmp $(dot-target).cmd) 171 172# Usage: $(call if_changed_rule,foo) 173# will check if $(cmd_foo) changed, or any of the prequisites changed, 174# and if so will execute $(rule_foo) 175if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \ 176 @set -e; \ 177 $(rule_$(1))) 178 179### 180# why - tell why a a target got build 181# enabled by make V=2 182# Output (listed in the order they are checked): 183# (1) - due to target is PHONY 184# (2) - due to target missing 185# (3) - due to: file1.h file2.h 186# (4) - due to command line change 187# (5) - due to missing .cmd file 188# (6) - due to target not in $(targets) 189# (1) PHONY targets are always build 190# (2) No target, so we better build it 191# (3) Prerequisite is newer than target 192# (4) The command line stored in the file named dir/.target.cmd 193# differed from actual command line. This happens when compiler 194# options changes 195# (5) No dir/.target.cmd file (used to store command line) 196# (6) No dir/.target.cmd file and target not listed in $(targets) 197# This is a good hint that there is a bug in the kbuild file 198ifeq ($(KBUILD_VERBOSE),2) 199why = \ 200 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \ 201 $(if $(wildcard $@), \ 202 $(if $(strip $(any-prereq)),- due to: $(any-prereq), \ 203 $(if $(arg-check), \ 204 $(if $(cmd_$@),- due to command line change, \ 205 $(if $(filter $@, $(targets)), \ 206 - due to missing .cmd file, \ 207 - due to $(notdir $@) not in $$(targets) \ 208 ) \ 209 ) \ 210 ) \ 211 ), \ 212 - due to target missing \ 213 ) \ 214 ) 215 216echo-why = $(call escsq, $(strip $(why))) 217endif 218