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