scripts/Kbuild.include

   1 ####
   2 # kbuild: Generic definitions
   3
   4 # Convinient variables
   5 comma   := ,
   6 empty   :=
   7 space   := $(empty) $(empty)
   8
   9 ###
  10 # The temporary file to save gcc -MD generated dependencies must not
  11 # contain a comma
  12 depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
  13
  14 ###
  15 # filechk is used to check if the content of a generated file is updated.
  16 # Sample usage:
  17 # define filechk_sample
  18 #       echo $KERNELRELEASE
  19 # endef
  20 # version.h : Makefile
  21 #       $(call filechk,sample)
  22 # The rule defined shall write to stdout the content of the new file.
  23 # The existing file will be compared with the new one.
  24 # - If no file exist it is created
  25 # - If the content differ the new file is used
  26 # - If they are equal no change, and no timestamp update
  27 # - stdin is piped in from the first prerequisite ($<) so one has
  28 #   to specify a valid file as first prerequisite (often the kbuild file)
  29 define filechk
  30         $(Q)set -e;                             \
  31         echo '  CHK     $@';                    \
  32         mkdir -p $(dir $@);                     \
  33         $(filechk_$(1)) < $< > $@.tmp;          \
  34         if [ -r $@ ] && cmp -s $@ $@.tmp; then  \
  35                 rm -f $@.tmp;                   \
  36         else                                    \
  37                 echo '  UPD     $@';            \
  38                 mv -f $@.tmp $@;                \
  39         fi
  40 endef
  41
  42 ###
  43 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
  44 # Usage:
  45 # $(Q)$(MAKE) $(build)=dir
  46 build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
  47
  48 # If quiet is set, only print short version of command
  49 cmd = @$(if $($(quiet)cmd_$(1)),\
  50       echo '  $(subst ','\'',$($(quiet)cmd_$(1)))' &&) $(cmd_$(1))
  51
  52 ###
  53 # if_changed      - execute command if any prerequisite is newer than
  54 #                   target, or command line has changed
  55 # if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
  56 #                   including used config symbols
  57 # if_changed_rule - as if_changed but execute rule instead
  58 # See Documentation/kbuild/makefiles.txt for more info
  59
  60 ifneq ($(KBUILD_NOCMDDEP),1)
  61 # Check if both arguments has same arguments. Result in empty string if equal
  62 # User may override this check using make KBUILD_NOCMDDEP=1
  63 arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )
  64 endif
  65
  66 # echo command. Short version is $(quiet) equals quiet, otherwise full command
  67 echo-cmd = $(if $($(quiet)cmd_$(1)), \
  68         echo '  $(subst ','\'',$($(quiet)cmd_$(1)))';)
  69
  70 # function to only execute the passed command if necessary
  71 # >'< substitution is for echo to work, >$< substitution to preserve $ when reloading .cmd file
  72 # note: when using inline perl scripts [perl -e '...$$t=1;...'] in $(cmd_xxx) double $$ your perl vars
  73 #
  74 if_changed = $(if $(strip $? $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
  75         @set -e; \
  76         $(echo-cmd) \
  77         $(cmd_$(1)); \
  78         echo 'cmd_$@ := $(subst $$,$$$$,$(subst ','\'',$(cmd_$(1))))' > $(@D)/.$(@F).cmd)
  79
  80 # execute the command and also postprocess generated .d dependencies
  81 # file
  82 if_changed_dep = $(if $(strip $? $(filter-out FORCE $(wildcard $^),$^)\
  83         $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),                  \
  84         @set -e; \
  85         $(echo-cmd) \
  86         $(cmd_$(1)); \
  87         scripts/basic/fixdep $(depfile) $@ '$(subst $$,$$$$,$(subst ','\'',$(cmd_$(1))))' > $(@D)/.$(@F).tmp; \
  88         rm -f $(depfile); \
  89         mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd)
  90
  91 # Usage: $(call if_changed_rule,foo)
  92 # will check if $(cmd_foo) changed, or any of the prequisites changed,
  93 # and if so will execute $(rule_foo)
  94 if_changed_rule = $(if $(strip $? $(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\
  95                         @set -e; \
  96                         $(rule_$(1)))