1#### 2# kbuild: Generic definitions 3 4# Convenient 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# filename of first prerequisite with directory and extension stripped 25baseprereq = $(basename $(notdir $<)) 26 27### 28# Escape single quote for use in echo statements 29escsq = $(subst $(squote),'\$(squote)',$1) 30 31### 32# Easy method for doing a status message 33 kecho := : 34 quiet_kecho := echo 35silent_kecho := : 36kecho := $($(quiet)kecho) 37 38### 39# filechk is used to check if the content of a generated file is updated. 40# Sample usage: 41# define filechk_sample 42# echo $KERNELRELEASE 43# endef 44# version.h : Makefile 45# $(call filechk,sample) 46# The rule defined shall write to stdout the content of the new file. 47# The existing file will be compared with the new one. 48# - If no file exist it is created 49# - If the content differ the new file is used 50# - If they are equal no change, and no timestamp update 51# - stdin is piped in from the first prerequisite ($<) so one has 52# to specify a valid file as first prerequisite (often the kbuild file) 53define filechk 54 $(Q)set -e; \ 55 $(kecho) ' CHK $@'; \ 56 mkdir -p $(dir $@); \ 57 $(filechk_$(1)) < $< > $@.tmp; \ 58 if [ -r $@ ] && cmp -s $@ $@.tmp; then \ 59 rm -f $@.tmp; \ 60 else \ 61 $(kecho) ' UPD $@'; \ 62 mv -f $@.tmp $@; \ 63 fi 64endef 65 66###### 67# gcc support functions 68# See documentation in Documentation/kbuild/makefiles.txt 69 70# cc-cross-prefix 71# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-) 72# Return first prefix where a prefix$(CC) is found in PATH. 73# If no $(CC) found in PATH with listed prefixes return nothing 74cc-cross-prefix = \ 75 $(word 1, $(foreach c,$(1), \ 76 $(shell set -e; \ 77 if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \ 78 echo $(c); \ 79 fi))) 80 81# output directory for tests below 82TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/) 83 84# try-run 85# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise) 86# Exit code chooses option. "$$TMP" is can be used as temporary file and 87# is automatically cleaned up. 88try-run = $(shell set -e; \ 89 TMP="$(TMPOUT).$$$$.tmp"; \ 90 TMPO="$(TMPOUT).$$$$.o"; \ 91 if ($(1)) >/dev/null 2>&1; \ 92 then echo "$(2)"; \ 93 else echo "$(3)"; \ 94 fi; \ 95 rm -f "$$TMP" "$$TMPO") 96 97# as-option 98# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,) 99 100as-option = $(call try-run,\ 101 $(CC) $(KBUILD_CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2)) 102 103# as-instr 104# Usage: cflags-y += $(call as-instr,instr,option1,option2) 105 106as-instr = $(call try-run,\ 107 /bin/echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3)) 108 109# cc-option 110# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586) 111 112cc-option = $(call try-run,\ 113 $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",$(1),$(2)) 114 115# cc-option-yn 116# Usage: flag := $(call cc-option-yn,-march=winchip-c6) 117cc-option-yn = $(call try-run,\ 118 $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",y,n) 119 120# cc-option-align 121# Prefix align with either -falign or -malign 122cc-option-align = $(subst -functions=0,,\ 123 $(call cc-option,-falign-functions=0,-malign-functions=0)) 124 125# cc-disable-warning 126# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable) 127cc-disable-warning = $(call try-run,\ 128 $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -xc /dev/null -o "$$TMP",-Wno-$(strip $(1))) 129 130# cc-version 131# Usage gcc-ver := $(call cc-version) 132cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC)) 133 134# cc-fullversion 135# Usage gcc-ver := $(call cc-fullversion) 136cc-fullversion = $(shell $(CONFIG_SHELL) \ 137 $(srctree)/scripts/gcc-version.sh -p $(CC)) 138 139# cc-ifversion 140# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1) 141cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3)) 142 143# cc-ldoption 144# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both) 145cc-ldoption = $(call try-run,\ 146 $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2)) 147 148# ld-option 149# Usage: LDFLAGS += $(call ld-option, -X) 150ld-option = $(call try-run,\ 151 $(CC) /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2)) 152 153# ar-option 154# Usage: KBUILD_ARFLAGS := $(call ar-option,D) 155# Important: no spaces around options 156ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2)) 157 158###### 159 160### 161# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= 162# Usage: 163# $(Q)$(MAKE) $(build)=dir 164build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj 165 166### 167# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj= 168# Usage: 169# $(Q)$(MAKE) $(modbuiltin)=dir 170modbuiltin := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.modbuiltin obj 171 172# Prefix -I with $(srctree) if it is not an absolute path. 173# skip if -I has no parameter 174addtree = $(if $(patsubst -I%,%,$(1)), \ 175$(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)) 176 177# Find all -I options and call addtree 178flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o))) 179 180# echo command. 181# Short version is used, if $(quiet) equals `quiet_', otherwise full one. 182echo-cmd = $(if $($(quiet)cmd_$(1)),\ 183 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';) 184 185# printing commands 186cmd = @$(echo-cmd) $(cmd_$(1)) 187 188# Add $(obj)/ for paths that are not absolute 189objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o))) 190 191### 192# if_changed - execute command if any prerequisite is newer than 193# target, or command line has changed 194# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies 195# including used config symbols 196# if_changed_rule - as if_changed but execute rule instead 197# See Documentation/kbuild/makefiles.txt for more info 198 199ifneq ($(KBUILD_NOCMDDEP),1) 200# Check if both arguments has same arguments. Result is empty string if equal. 201# User may override this check using make KBUILD_NOCMDDEP=1 202arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \ 203 $(filter-out $(cmd_$@), $(cmd_$(1))) ) 204else 205arg-check = $(if $(strip $(cmd_$@)),,1) 206endif 207 208# >'< substitution is for echo to work, 209# >$< substitution to preserve $ when reloading .cmd file 210# note: when using inline perl scripts [perl -e '...$$t=1;...'] 211# in $(cmd_xxx) double $$ your perl vars 212make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1))))) 213 214# Find any prerequisites that is newer than target or that does not exist. 215# PHONY targets skipped in both cases. 216any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^) 217 218# Execute command if command has changed or prerequisite(s) are updated. 219# 220if_changed = $(if $(strip $(any-prereq) $(arg-check)), \ 221 @set -e; \ 222 $(echo-cmd) $(cmd_$(1)); \ 223 echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd) 224 225# Execute the command and also postprocess generated .d dependencies file. 226if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \ 227 @set -e; \ 228 $(echo-cmd) $(cmd_$(1)); \ 229 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\ 230 rm -f $(depfile); \ 231 mv -f $(dot-target).tmp $(dot-target).cmd) 232 233# Usage: $(call if_changed_rule,foo) 234# Will check if $(cmd_foo) or any of the prerequisites changed, 235# and if so will execute $(rule_foo). 236if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \ 237 @set -e; \ 238 $(rule_$(1))) 239 240### 241# why - tell why a a target got build 242# enabled by make V=2 243# Output (listed in the order they are checked): 244# (1) - due to target is PHONY 245# (2) - due to target missing 246# (3) - due to: file1.h file2.h 247# (4) - due to command line change 248# (5) - due to missing .cmd file 249# (6) - due to target not in $(targets) 250# (1) PHONY targets are always build 251# (2) No target, so we better build it 252# (3) Prerequisite is newer than target 253# (4) The command line stored in the file named dir/.target.cmd 254# differed from actual command line. This happens when compiler 255# options changes 256# (5) No dir/.target.cmd file (used to store command line) 257# (6) No dir/.target.cmd file and target not listed in $(targets) 258# This is a good hint that there is a bug in the kbuild file 259ifeq ($(KBUILD_VERBOSE),2) 260why = \ 261 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \ 262 $(if $(wildcard $@), \ 263 $(if $(strip $(any-prereq)),- due to: $(any-prereq), \ 264 $(if $(arg-check), \ 265 $(if $(cmd_$@),- due to command line change, \ 266 $(if $(filter $@, $(targets)), \ 267 - due to missing .cmd file, \ 268 - due to $(notdir $@) not in $$(targets) \ 269 ) \ 270 ) \ 271 ) \ 272 ), \ 273 - due to target missing \ 274 ) \ 275 ) 276 277echo-why = $(call escsq, $(strip $(why))) 278endif 279