1#### 2# kbuild: Generic definitions 3 4# Convenient variables 5comma := , 6quote := " 7squote := ' 8empty := 9space := $(empty) $(empty) 10 11### 12# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o 13dot-target = $(dir $@).$(notdir $@) 14 15### 16# The temporary file to save gcc -MD generated dependencies must not 17# contain a comma 18depfile = $(subst $(comma),_,$(dot-target).d) 19 20### 21# filename of target with directory and extension stripped 22basetarget = $(basename $(notdir $@)) 23 24### 25# filename of first prerequisite with directory and extension stripped 26baseprereq = $(basename $(notdir $<)) 27 28### 29# Escape single quote for use in echo statements 30escsq = $(subst $(squote),'\$(squote)',$1) 31 32### 33# Easy method for doing a status message 34 kecho := : 35 quiet_kecho := echo 36silent_kecho := : 37kecho := $($(quiet)kecho) 38 39### 40# filechk is used to check if the content of a generated file is updated. 41# Sample usage: 42# define filechk_sample 43# echo $KERNELRELEASE 44# endef 45# version.h : Makefile 46# $(call filechk,sample) 47# The rule defined shall write to stdout the content of the new file. 48# The existing file will be compared with the new one. 49# - If no file exist it is created 50# - If the content differ the new file is used 51# - If they are equal no change, and no timestamp update 52# - stdin is piped in from the first prerequisite ($<) so one has 53# to specify a valid file as first prerequisite (often the kbuild file) 54define filechk 55 $(Q)set -e; \ 56 $(kecho) ' CHK $@'; \ 57 mkdir -p $(dir $@); \ 58 $(filechk_$(1)) < $< > $@.tmp; \ 59 if [ -r $@ ] && cmp -s $@ $@.tmp; then \ 60 rm -f $@.tmp; \ 61 else \ 62 $(kecho) ' UPD $@'; \ 63 mv -f $@.tmp $@; \ 64 fi 65endef 66 67###### 68# gcc support functions 69# See documentation in Documentation/kbuild/makefiles.txt 70 71# cc-cross-prefix 72# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-) 73# Return first prefix where a prefix$(CC) is found in PATH. 74# If no $(CC) found in PATH with listed prefixes return nothing 75cc-cross-prefix = \ 76 $(word 1, $(foreach c,$(1), \ 77 $(shell set -e; \ 78 if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \ 79 echo $(c); \ 80 fi))) 81 82# output directory for tests below 83TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/) 84 85# try-run 86# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise) 87# Exit code chooses option. "$$TMP" is can be used as temporary file and 88# is automatically cleaned up. 89try-run = $(shell set -e; \ 90 TMP="$(TMPOUT).$$$$.tmp"; \ 91 TMPO="$(TMPOUT).$$$$.o"; \ 92 if ($(1)) >/dev/null 2>&1; \ 93 then echo "$(2)"; \ 94 else echo "$(3)"; \ 95 fi; \ 96 rm -f "$$TMP" "$$TMPO") 97 98# as-option 99# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,) 100 101as-option = $(call try-run,\ 102 $(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2)) 103 104# as-instr 105# Usage: cflags-y += $(call as-instr,instr,option1,option2) 106 107as-instr = $(call try-run,\ 108 printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3)) 109 110# cc-option 111# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586) 112 113cc-option = $(call try-run,\ 114 $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2)) 115 116# cc-option-yn 117# Usage: flag := $(call cc-option-yn,-march=winchip-c6) 118cc-option-yn = $(call try-run,\ 119 $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n) 120 121# cc-option-align 122# Prefix align with either -falign or -malign 123cc-option-align = $(subst -functions=0,,\ 124 $(call cc-option,-falign-functions=0,-malign-functions=0)) 125 126# cc-disable-warning 127# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable) 128cc-disable-warning = $(call try-run,\ 129 $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) 130 131# cc-version 132# Usage gcc-ver := $(call cc-version) 133cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC)) 134 135# cc-fullversion 136# Usage gcc-ver := $(call cc-fullversion) 137cc-fullversion = $(shell $(CONFIG_SHELL) \ 138 $(srctree)/scripts/gcc-version.sh -p $(CC)) 139 140# cc-ifversion 141# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1) 142cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3)) 143 144# cc-ldoption 145# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both) 146cc-ldoption = $(call try-run,\ 147 $(CC) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2)) 148 149# ld-option 150# Usage: LDFLAGS += $(call ld-option, -X) 151ld-option = $(call try-run,\ 152 $(CC) -x c /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2)) 153 154# ar-option 155# Usage: KBUILD_ARFLAGS := $(call ar-option,D) 156# Important: no spaces around options 157ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2)) 158 159# ld-version 160# Usage: $(call ld-version) 161# Note this is mainly for HJ Lu's 3 number binutil versions 162ld-version = $(shell $(LD) --version | $(srctree)/scripts/ld-version.sh) 163 164# ld-ifversion 165# Usage: $(call ld-ifversion, -ge, 22252, y) 166ld-ifversion = $(shell [ $(call ld-version) $(1) $(2) ] && echo $(3)) 167 168###### 169 170### 171# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= 172# Usage: 173# $(Q)$(MAKE) $(build)=dir 174build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj 175 176### 177# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.modbuiltin obj= 178# Usage: 179# $(Q)$(MAKE) $(modbuiltin)=dir 180modbuiltin := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.modbuiltin obj 181 182# Prefix -I with $(srctree) if it is not an absolute path. 183# skip if -I has no parameter 184addtree = $(if $(patsubst -I%,%,$(1)), \ 185$(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)) 186 187# Find all -I options and call addtree 188flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o))) 189 190# echo command. 191# Short version is used, if $(quiet) equals `quiet_', otherwise full one. 192echo-cmd = $(if $($(quiet)cmd_$(1)),\ 193 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';) 194 195# printing commands 196cmd = @$(echo-cmd) $(cmd_$(1)) 197 198# Add $(obj)/ for paths that are not absolute 199objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o))) 200 201### 202# if_changed - execute command if any prerequisite is newer than 203# target, or command line has changed 204# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies 205# including used config symbols 206# if_changed_rule - as if_changed but execute rule instead 207# See Documentation/kbuild/makefiles.txt for more info 208 209ifneq ($(KBUILD_NOCMDDEP),1) 210# Check if both arguments has same arguments. Result is empty string if equal. 211# User may override this check using make KBUILD_NOCMDDEP=1 212arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \ 213 $(filter-out $(cmd_$@), $(cmd_$(1))) ) 214else 215arg-check = $(if $(strip $(cmd_$@)),,1) 216endif 217 218# >'< substitution is for echo to work, 219# >$< substitution to preserve $ when reloading .cmd file 220# note: when using inline perl scripts [perl -e '...$$t=1;...'] 221# in $(cmd_xxx) double $$ your perl vars 222make-cmd = $(subst \\,\\\\,$(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))) 223 224# Find any prerequisites that is newer than target or that does not exist. 225# PHONY targets skipped in both cases. 226any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^) 227 228# Execute command if command has changed or prerequisite(s) are updated. 229# 230if_changed = $(if $(strip $(any-prereq) $(arg-check)), \ 231 @set -e; \ 232 $(echo-cmd) $(cmd_$(1)); \ 233 echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd) 234 235# Execute the command and also postprocess generated .d dependencies file. 236if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \ 237 @set -e; \ 238 $(echo-cmd) $(cmd_$(1)); \ 239 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\ 240 rm -f $(depfile); \ 241 mv -f $(dot-target).tmp $(dot-target).cmd) 242 243# Usage: $(call if_changed_rule,foo) 244# Will check if $(cmd_foo) or any of the prerequisites changed, 245# and if so will execute $(rule_foo). 246if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \ 247 @set -e; \ 248 $(rule_$(1))) 249 250### 251# why - tell why a a target got build 252# enabled by make V=2 253# Output (listed in the order they are checked): 254# (1) - due to target is PHONY 255# (2) - due to target missing 256# (3) - due to: file1.h file2.h 257# (4) - due to command line change 258# (5) - due to missing .cmd file 259# (6) - due to target not in $(targets) 260# (1) PHONY targets are always build 261# (2) No target, so we better build it 262# (3) Prerequisite is newer than target 263# (4) The command line stored in the file named dir/.target.cmd 264# differed from actual command line. This happens when compiler 265# options changes 266# (5) No dir/.target.cmd file (used to store command line) 267# (6) No dir/.target.cmd file and target not listed in $(targets) 268# This is a good hint that there is a bug in the kbuild file 269ifeq ($(KBUILD_VERBOSE),2) 270why = \ 271 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \ 272 $(if $(wildcard $@), \ 273 $(if $(strip $(any-prereq)),- due to: $(any-prereq), \ 274 $(if $(arg-check), \ 275 $(if $(cmd_$@),- due to command line change, \ 276 $(if $(filter $@, $(targets)), \ 277 - due to missing .cmd file, \ 278 - due to $(notdir $@) not in $$(targets) \ 279 ) \ 280 ) \ 281 ) \ 282 ), \ 283 - due to target missing \ 284 ) \ 285 ) 286 287echo-why = $(call escsq, $(strip $(why))) 288endif 289