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