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