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