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).$$$$.tmp"; \ 86 TMPO="$(TMPOUT).$$$$.o"; \ 87 if ($(1)) >/dev/null 2>&1; \ 88 then echo "$(2)"; \ 89 else echo "$(3)"; \ 90 fi; \ 91 rm -f "$$TMP" "$$TMPO") 92 93# as-option 94# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,) 95 96as-option = $(call try-run,\ 97 $(CC) $(KBUILD_CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2)) 98 99# as-instr 100# Usage: cflags-y += $(call as-instr,instr,option1,option2) 101 102as-instr = $(call try-run,\ 103 /bin/echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3)) 104 105# cc-option 106# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586) 107 108cc-option = $(call try-run,\ 109 $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",$(1),$(2)) 110 111# cc-option-yn 112# Usage: flag := $(call cc-option-yn,-march=winchip-c6) 113cc-option-yn = $(call try-run,\ 114 $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",y,n) 115 116# cc-option-align 117# Prefix align with either -falign or -malign 118cc-option-align = $(subst -functions=0,,\ 119 $(call cc-option,-falign-functions=0,-malign-functions=0)) 120 121# cc-version 122# Usage gcc-ver := $(call cc-version) 123cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC)) 124 125# cc-fullversion 126# Usage gcc-ver := $(call cc-fullversion) 127cc-fullversion = $(shell $(CONFIG_SHELL) \ 128 $(srctree)/scripts/gcc-version.sh -p $(CC)) 129 130# cc-ifversion 131# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1) 132cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3)) 133 134# cc-ldoption 135# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both) 136cc-ldoption = $(call try-run,\ 137 $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2)) 138 139# ld-option 140# Usage: LDFLAGS += $(call ld-option, -X) 141ld-option = $(call try-run,\ 142 $(CC) /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2)) 143 144###### 145 146### 147# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= 148# Usage: 149# $(Q)$(MAKE) $(build)=dir 150build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj 151 152# Prefix -I with $(srctree) if it is not an absolute path. 153# skip if -I has no parameter 154addtree = $(if $(patsubst -I%,%,$(1)), \ 155$(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)) 156 157# Find all -I options and call addtree 158flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o))) 159 160# echo command. 161# Short version is used, if $(quiet) equals `quiet_', otherwise full one. 162echo-cmd = $(if $($(quiet)cmd_$(1)),\ 163 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';) 164 165# printing commands 166cmd = @$(echo-cmd) $(cmd_$(1)) 167 168# Add $(obj)/ for paths that are not absolute 169objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o))) 170 171### 172# if_changed - execute command if any prerequisite is newer than 173# target, or command line has changed 174# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies 175# including used config symbols 176# if_changed_rule - as if_changed but execute rule instead 177# See Documentation/kbuild/makefiles.txt for more info 178 179ifneq ($(KBUILD_NOCMDDEP),1) 180# Check if both arguments has same arguments. Result is empty string if equal. 181# User may override this check using make KBUILD_NOCMDDEP=1 182arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \ 183 $(filter-out $(cmd_$@), $(cmd_$(1))) ) 184endif 185 186# >'< substitution is for echo to work, 187# >$< substitution to preserve $ when reloading .cmd file 188# note: when using inline perl scripts [perl -e '...$$t=1;...'] 189# in $(cmd_xxx) double $$ your perl vars 190make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1))))) 191 192# Find any prerequisites that is newer than target or that does not exist. 193# PHONY targets skipped in both cases. 194any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^) 195 196# Execute command if command has changed or prerequisite(s) are updated. 197# 198if_changed = $(if $(strip $(any-prereq) $(arg-check)), \ 199 @set -e; \ 200 $(echo-cmd) $(cmd_$(1)); \ 201 echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd) 202 203# Execute the command and also postprocess generated .d dependencies file. 204if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \ 205 @set -e; \ 206 $(echo-cmd) $(cmd_$(1)); \ 207 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\ 208 rm -f $(depfile); \ 209 mv -f $(dot-target).tmp $(dot-target).cmd) 210 211# Usage: $(call if_changed_rule,foo) 212# Will check if $(cmd_foo) or any of the prerequisites changed, 213# and if so will execute $(rule_foo). 214if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \ 215 @set -e; \ 216 $(rule_$(1))) 217 218### 219# why - tell why a a target got build 220# enabled by make V=2 221# Output (listed in the order they are checked): 222# (1) - due to target is PHONY 223# (2) - due to target missing 224# (3) - due to: file1.h file2.h 225# (4) - due to command line change 226# (5) - due to missing .cmd file 227# (6) - due to target not in $(targets) 228# (1) PHONY targets are always build 229# (2) No target, so we better build it 230# (3) Prerequisite is newer than target 231# (4) The command line stored in the file named dir/.target.cmd 232# differed from actual command line. This happens when compiler 233# options changes 234# (5) No dir/.target.cmd file (used to store command line) 235# (6) No dir/.target.cmd file and target not listed in $(targets) 236# This is a good hint that there is a bug in the kbuild file 237ifeq ($(KBUILD_VERBOSE),2) 238why = \ 239 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \ 240 $(if $(wildcard $@), \ 241 $(if $(strip $(any-prereq)),- due to: $(any-prereq), \ 242 $(if $(arg-check), \ 243 $(if $(cmd_$@),- due to command line change, \ 244 $(if $(filter $@, $(targets)), \ 245 - due to missing .cmd file, \ 246 - due to $(notdir $@) not in $$(targets) \ 247 ) \ 248 ) \ 249 ) \ 250 ), \ 251 - due to target missing \ 252 ) \ 253 ) 254 255echo-why = $(call escsq, $(strip $(why))) 256endif 257