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 chk_filechk = : 43 quiet_chk_filechk = echo ' CHK $@' 44silent_chk_filechk = : 45 upd_filechk = : 46 quiet_upd_filechk = echo ' UPD $@' 47silent_upd_filechk = : 48 49define filechk 50 $(Q)set -e; \ 51 $($(quiet)chk_filechk); \ 52 mkdir -p $(dir $@); \ 53 $(filechk_$(1)) < $< > $@.tmp; \ 54 if [ -r $@ ] && cmp -s $@ $@.tmp; then \ 55 rm -f $@.tmp; \ 56 else \ 57 $($(quiet)upd_filechk); \ 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) -S -xc /dev/null -o "$$TMP",$(1),$(2)) 109 110# cc-option-yn 111# Usage: flag := $(call cc-option-yn,-march=winchip-c6) 112cc-option-yn = $(call try-run,\ 113 $(CC) $(KBUILD_CFLAGS) $(1) -S -xc /dev/null -o "$$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 "$$TMP",$(1),$(2)) 137 138###### 139 140### 141# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= 142# Usage: 143# $(Q)$(MAKE) $(build)=dir 144build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj 145 146# Prefix -I with $(srctree) if it is not an absolute path. 147addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1) 148 149# Find all -I options and call addtree 150flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o))) 151 152# echo command. 153# Short version is used, if $(quiet) equals `quiet_', otherwise full one. 154echo-cmd = $(if $($(quiet)cmd_$(1)),\ 155 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';) 156 157# printing commands 158cmd = @$(echo-cmd) $(cmd_$(1)) 159 160# Add $(obj)/ for paths that are not absolute 161objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o))) 162 163### 164# if_changed - execute command if any prerequisite is newer than 165# target, or command line has changed 166# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies 167# including used config symbols 168# if_changed_rule - as if_changed but execute rule instead 169# See Documentation/kbuild/makefiles.txt for more info 170 171ifneq ($(KBUILD_NOCMDDEP),1) 172# Check if both arguments has same arguments. Result is empty string if equal. 173# User may override this check using make KBUILD_NOCMDDEP=1 174arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \ 175 $(filter-out $(cmd_$@), $(cmd_$(1))) ) 176endif 177 178# >'< substitution is for echo to work, 179# >$< substitution to preserve $ when reloading .cmd file 180# note: when using inline perl scripts [perl -e '...$$t=1;...'] 181# in $(cmd_xxx) double $$ your perl vars 182make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1))))) 183 184# Find any prerequisites that is newer than target or that does not exist. 185# PHONY targets skipped in both cases. 186any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^) 187 188# Execute command if command has changed or prerequisite(s) are updated. 189# 190if_changed = $(if $(strip $(any-prereq) $(arg-check)), \ 191 @set -e; \ 192 $(echo-cmd) $(cmd_$(1)); \ 193 echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd) 194 195# Execute the command and also postprocess generated .d dependencies file. 196if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \ 197 @set -e; \ 198 $(echo-cmd) $(cmd_$(1)); \ 199 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\ 200 rm -f $(depfile); \ 201 mv -f $(dot-target).tmp $(dot-target).cmd) 202 203# Usage: $(call if_changed_rule,foo) 204# Will check if $(cmd_foo) or any of the prerequisites changed, 205# and if so will execute $(rule_foo). 206if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \ 207 @set -e; \ 208 $(rule_$(1))) 209 210### 211# why - tell why a a target got build 212# enabled by make V=2 213# Output (listed in the order they are checked): 214# (1) - due to target is PHONY 215# (2) - due to target missing 216# (3) - due to: file1.h file2.h 217# (4) - due to command line change 218# (5) - due to missing .cmd file 219# (6) - due to target not in $(targets) 220# (1) PHONY targets are always build 221# (2) No target, so we better build it 222# (3) Prerequisite is newer than target 223# (4) The command line stored in the file named dir/.target.cmd 224# differed from actual command line. This happens when compiler 225# options changes 226# (5) No dir/.target.cmd file (used to store command line) 227# (6) No dir/.target.cmd file and target not listed in $(targets) 228# This is a good hint that there is a bug in the kbuild file 229ifeq ($(KBUILD_VERBOSE),2) 230why = \ 231 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \ 232 $(if $(wildcard $@), \ 233 $(if $(strip $(any-prereq)),- due to: $(any-prereq), \ 234 $(if $(arg-check), \ 235 $(if $(cmd_$@),- due to command line change, \ 236 $(if $(filter $@, $(targets)), \ 237 - due to missing .cmd file, \ 238 - due to $(notdir $@) not in $$(targets) \ 239 ) \ 240 ) \ 241 ) \ 242 ), \ 243 - due to target missing \ 244 ) \ 245 ) 246 247echo-why = $(call escsq, $(strip $(why))) 248endif 249