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# 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# try-run 63# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise) 64# Exit code chooses option. "$$TMP" is can be used as temporary file and 65# is automatically cleaned up. 66try-run = $(shell set -e; \ 67 TMP="$(TMPOUT).$$$$.tmp"; \ 68 if ($(1)) >/dev/null 2>&1; \ 69 then echo "$(2)"; \ 70 else echo "$(3)"; \ 71 fi; \ 72 rm -f "$$TMP") 73 74# as-option 75# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,) 76 77as-option = $(call try-run,\ 78 $(CC) $(KBUILD_CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2)) 79 80# as-instr 81# Usage: cflags-y += $(call as-instr,instr,option1,option2) 82 83as-instr = $(call try-run,\ 84 echo -e "$(1)" | $(CC) $(AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3)) 85 86# cc-option 87# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586) 88 89cc-option = $(call try-run,\ 90 $(CC) $(KBUILD_CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",$(1),$(2)) 91 92# cc-option-yn 93# Usage: flag := $(call cc-option-yn,-march=winchip-c6) 94cc-option-yn = $(call try-run,\ 95 $(CC) $(KBUILD_CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",y,n) 96 97# cc-option-align 98# Prefix align with either -falign or -malign 99cc-option-align = $(subst -functions=0,,\ 100 $(call cc-option,-falign-functions=0,-malign-functions=0)) 101 102# cc-version 103# Usage gcc-ver := $(call cc-version) 104cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC)) 105 106# cc-fullversion 107# Usage gcc-ver := $(call cc-fullversion) 108cc-fullversion = $(shell $(CONFIG_SHELL) \ 109 $(srctree)/scripts/gcc-version.sh -p $(CC)) 110 111# cc-ifversion 112# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1) 113cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3)) 114 115# ld-option 116# Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both) 117ld-option = $(call try-run,\ 118 $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2)) 119 120###### 121 122### 123# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= 124# Usage: 125# $(Q)$(MAKE) $(build)=dir 126build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj 127 128# Prefix -I with $(srctree) if it is not an absolute path. 129addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1) 130 131# Find all -I options and call addtree 132flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o))) 133 134# echo command. 135# Short version is used, if $(quiet) equals `quiet_', otherwise full one. 136echo-cmd = $(if $($(quiet)cmd_$(1)),\ 137 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';) 138 139# printing commands 140cmd = @$(echo-cmd) $(cmd_$(1)) 141 142# Add $(obj)/ for paths that are not absolute 143objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o))) 144 145### 146# if_changed - execute command if any prerequisite is newer than 147# target, or command line has changed 148# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies 149# including used config symbols 150# if_changed_rule - as if_changed but execute rule instead 151# See Documentation/kbuild/makefiles.txt for more info 152 153ifneq ($(KBUILD_NOCMDDEP),1) 154# Check if both arguments has same arguments. Result is empty string if equal. 155# User may override this check using make KBUILD_NOCMDDEP=1 156arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \ 157 $(filter-out $(cmd_$@), $(cmd_$(1))) ) 158endif 159 160# >'< substitution is for echo to work, 161# >$< substitution to preserve $ when reloading .cmd file 162# note: when using inline perl scripts [perl -e '...$$t=1;...'] 163# in $(cmd_xxx) double $$ your perl vars 164make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1))))) 165 166# Find any prerequisites that is newer than target or that does not exist. 167# PHONY targets skipped in both cases. 168any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^) 169 170# Execute command if command has changed or prerequisite(s) are updated. 171# 172if_changed = $(if $(strip $(any-prereq) $(arg-check)), \ 173 @set -e; \ 174 $(echo-cmd) $(cmd_$(1)); \ 175 echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd) 176 177# Execute the command and also postprocess generated .d dependencies file. 178if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \ 179 @set -e; \ 180 $(echo-cmd) $(cmd_$(1)); \ 181 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\ 182 rm -f $(depfile); \ 183 mv -f $(dot-target).tmp $(dot-target).cmd) 184 185# Usage: $(call if_changed_rule,foo) 186# Will check if $(cmd_foo) or any of the prerequisites changed, 187# and if so will execute $(rule_foo). 188if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \ 189 @set -e; \ 190 $(rule_$(1))) 191 192### 193# why - tell why a a target got build 194# enabled by make V=2 195# Output (listed in the order they are checked): 196# (1) - due to target is PHONY 197# (2) - due to target missing 198# (3) - due to: file1.h file2.h 199# (4) - due to command line change 200# (5) - due to missing .cmd file 201# (6) - due to target not in $(targets) 202# (1) PHONY targets are always build 203# (2) No target, so we better build it 204# (3) Prerequisite is newer than target 205# (4) The command line stored in the file named dir/.target.cmd 206# differed from actual command line. This happens when compiler 207# options changes 208# (5) No dir/.target.cmd file (used to store command line) 209# (6) No dir/.target.cmd file and target not listed in $(targets) 210# This is a good hint that there is a bug in the kbuild file 211ifeq ($(KBUILD_VERBOSE),2) 212why = \ 213 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \ 214 $(if $(wildcard $@), \ 215 $(if $(strip $(any-prereq)),- due to: $(any-prereq), \ 216 $(if $(arg-check), \ 217 $(if $(cmd_$@),- due to command line change, \ 218 $(if $(filter $@, $(targets)), \ 219 - due to missing .cmd file, \ 220 - due to $(notdir $@) not in $$(targets) \ 221 ) \ 222 ) \ 223 ) \ 224 ), \ 225 - due to target missing \ 226 ) \ 227 ) 228 229echo-why = $(call escsq, $(strip $(why))) 230endif 231