scripts/Kbuild.include

   1 ####
   2 # kbuild: Generic definitions
   3
   4 # Convinient variables
   5 comma   := ,
   6 squote  := '
   7 empty   :=
   8 space   := $(empty) $(empty)
   9
  10 ###
  11 # The temporary file to save gcc -MD generated dependencies must not
  12 # contain a comma
  13 depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
  14
  15 ###
  16 # Escape single quote for use in echo statements
  17 escsq = $(subst $(squote),'\$(squote)',$1)
  18
  19 ###
  20 # filechk is used to check if the content of a generated file is updated.
  21 # Sample usage:
  22 # define filechk_sample
  23 #       echo $KERNELRELEASE
  24 # endef
  25 # version.h : Makefile
  26 #       $(call filechk,sample)
  27 # The rule defined shall write to stdout the content of the new file.
  28 # The existing file will be compared with the new one.
  29 # - If no file exist it is created
  30 # - If the content differ the new file is used
  31 # - If they are equal no change, and no timestamp update
  32 # - stdin is piped in from the first prerequisite ($<) so one has
  33 #   to specify a valid file as first prerequisite (often the kbuild file)
  34 define filechk
  35         $(Q)set -e;                             \
  36         echo '  CHK     $@';                    \
  37         mkdir -p $(dir $@);                     \
  38         $(filechk_$(1)) < $< > $@.tmp;          \
  39         if [ -r $@ ] && cmp -s $@ $@.tmp; then  \
  40                 rm -f $@.tmp;                   \
  41         else                                    \
  42                 echo '  UPD     $@';            \
  43                 mv -f $@.tmp $@;                \
  44         fi
  45 endef
  46
  47 ######
  48 # gcc support functions
  49 # See documentation in Documentation/kbuild/makefiles.txt
  50
  51 # as-option
  52 # Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,)
  53
  54 as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \
  55              -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \
  56              else echo "$(2)"; fi ;)
  57
  58 # cc-option
  59 # Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586)
  60
  61 cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
  62              > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
  63
  64 # cc-option-yn
  65 # Usage: flag := $(call cc-option-yn, -march=winchip-c6)
  66 cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
  67                 > /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
  68
  69 # cc-option-align
  70 # Prefix align with either -falign or -malign
  71 cc-option-align = $(subst -functions=0,,\
  72         $(call cc-option,-falign-functions=0,-malign-functions=0))
  73
  74 # cc-version
  75 # Usage gcc-ver := $(call cc-version, $(CC))
  76 cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh \
  77               $(if $(1), $(1), $(CC)))
  78
  79 # cc-ifversion
  80 # Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
  81 cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \
  82                        echo $(3); fi;)
  83
  84 ###
  85 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
  86 # Usage:
  87 # $(Q)$(MAKE) $(build)=dir
  88 build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
  89
  90 # If quiet is set, only print short version of command
  91 cmd = @$(echo-cmd) $(cmd_$(1))
  92
  93 # Add $(obj)/ for paths that is not absolute
  94 objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
  95
  96 ###
  97 # if_changed      - execute command if any prerequisite is newer than
  98 #                   target, or command line has changed
  99 # if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
 100 #                   including used config symbols
 101 # if_changed_rule - as if_changed but execute rule instead
 102 # See Documentation/kbuild/makefiles.txt for more info
 103
 104 ifneq ($(KBUILD_NOCMDDEP),1)
 105 # Check if both arguments has same arguments. Result in empty string if equal
 106 # User may override this check using make KBUILD_NOCMDDEP=1
 107 arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )
 108 endif
 109
 110 # echo command. Short version is $(quiet) equals quiet, otherwise full command
 111 echo-cmd = $(if $($(quiet)cmd_$(1)), \
 112         echo '  $(call escsq,$($(quiet)cmd_$(1)))';)
 113
 114 make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
 115
 116 # function to only execute the passed command if necessary
 117 # >'< substitution is for echo to work, >$< substitution to preserve $ when reloading .cmd file
 118 # note: when using inline perl scripts [perl -e '...$$t=1;...'] in $(cmd_xxx) double $$ your perl vars
 119 #
 120 if_changed = $(if $(strip $(filter-out $(PHONY),$?)          \
 121                 $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
 122         @set -e; \
 123         $(echo-cmd) $(cmd_$(1)); \
 124         echo 'cmd_$@ := $(make-cmd)' > $(@D)/.$(@F).cmd)
 125
 126 # execute the command and also postprocess generated .d dependencies
 127 # file
 128 if_changed_dep = $(if $(strip $(filter-out $(PHONY),$?)  \
 129                 $(filter-out FORCE $(wildcard $^),$^)    \
 130         $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),     \
 131         @set -e; \
 132         $(echo-cmd) $(cmd_$(1)); \
 133         scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(@D)/.$(@F).tmp; \
 134         rm -f $(depfile); \
 135         mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd)
 136
 137 # Usage: $(call if_changed_rule,foo)
 138 # will check if $(cmd_foo) changed, or any of the prequisites changed,
 139 # and if so will execute $(rule_foo)
 140 if_changed_rule = $(if $(strip $(filter-out $(PHONY),$?)            \
 141                         $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\
 142                         @set -e; \
 143                         $(rule_$(1)))