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 # Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
  12 dot-target = $(dir $@).$(notdir $@)
  13
  14 ###
  15 # The temporary file to save gcc -MD generated dependencies must not
  16 # contain a comma
  17 depfile = $(subst $(comma),_,$(dot-target).d)
  18
  19 ###
  20 # filename of target with directory and extension stripped
  21 basetarget = $(basename $(notdir $@))
  22
  23 ###
  24 # Escape single quote for use in echo statements
  25 escsq = $(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 define 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
  53 endef
  54
  55 ######
  56 # gcc support functions
  57 # See documentation in Documentation/kbuild/makefiles.txt
  58
  59 # as-option
  60 # Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,)
  61
  62 as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \
  63              -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \
  64              else echo "$(2)"; fi ;)
  65
  66 # cc-option
  67 # Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586)
  68
  69 cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
  70              > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
  71
  72 # cc-option-yn
  73 # Usage: flag := $(call cc-option-yn, -march=winchip-c6)
  74 cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
  75                 > /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
  76
  77 # cc-option-align
  78 # Prefix align with either -falign or -malign
  79 cc-option-align = $(subst -functions=0,,\
  80         $(call cc-option,-falign-functions=0,-malign-functions=0))
  81
  82 # cc-version
  83 # Usage gcc-ver := $(call cc-version, $(CC))
  84 cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
  85
  86 # cc-ifversion
  87 # Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
  88 cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \
  89                        echo $(3); fi;)
  90
  91 # ld-option
  92 # Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
  93 ld-option = $(shell if $(CC) $(1) \
  94                              -nostdlib -o ldtest$$$$.out -xc /dev/null \
  95              > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi; \
  96              rm -f ldtest$$$$.out)
  97
  98 ###
  99 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
 100 # Usage:
 101 # $(Q)$(MAKE) $(build)=dir
 102 build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
 103
 104 # Prefix -I with $(srctree) if it is not an absolute path
 105 addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
 106 # Find all -I options and call addtree
 107 flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
 108
 109 # If quiet is set, only print short version of command
 110 cmd = @$(echo-cmd) $(cmd_$(1))
 111
 112 # Add $(obj)/ for paths that is not absolute
 113 objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
 114
 115 ###
 116 # if_changed      - execute command if any prerequisite is newer than
 117 #                   target, or command line has changed
 118 # if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
 119 #                   including used config symbols
 120 # if_changed_rule - as if_changed but execute rule instead
 121 # See Documentation/kbuild/makefiles.txt for more info
 122
 123 ifneq ($(KBUILD_NOCMDDEP),1)
 124 # Check if both arguments has same arguments. Result in empty string if equal
 125 # User may override this check using make KBUILD_NOCMDDEP=1
 126 arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
 127                     $(filter-out $(cmd_$@),   $(cmd_$(1))) )
 128 endif
 129
 130 # echo command. Short version is $(quiet) equals quiet, otherwise full command
 131 echo-cmd = $(if $($(quiet)cmd_$(1)), \
 132         echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
 133
 134 # >'< substitution is for echo to work,
 135 # >$< substitution to preserve $ when reloading .cmd file
 136 # note: when using inline perl scripts [perl -e '...$$t=1;...']
 137 # in $(cmd_xxx) double $$ your perl vars
 138 make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
 139
 140 # Find any prerequisites that is newer than target or that does not exist.
 141 # PHONY targets skipped in both cases.
 142 any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
 143
 144 # Execute command if command has changed or prerequisitei(s) are updated
 145 #
 146 if_changed = $(if $(strip $(any-prereq) $(arg-check)),                       \
 147         @set -e;                                                             \
 148         $(echo-cmd) $(cmd_$(1));                                             \
 149         echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
 150
 151 # execute the command and also postprocess generated .d dependencies
 152 # file
 153 if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ),                  \
 154         @set -e;                                                             \
 155         $(echo-cmd) $(cmd_$(1));                                             \
 156         scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
 157         rm -f $(depfile);                                                    \
 158         mv -f $(dot-target).tmp $(dot-target).cmd)
 159
 160 # Usage: $(call if_changed_rule,foo)
 161 # will check if $(cmd_foo) changed, or any of the prequisites changed,
 162 # and if so will execute $(rule_foo)
 163 if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ),                 \
 164         @set -e;                                                             \
 165         $(rule_$(1)))
 166
 167 ###
 168 # why - tell why a a target got build
 169 #       enabled by make V=2
 170 #       Output (listed in the order they are checked):
 171 #          (1) - due to target is PHONY
 172 #          (2) - due to target missing
 173 #          (3) - due to: file1.h file2.h
 174 #          (4) - due to command line change
 175 #          (5) - due to missing .cmd file
 176 #          (6) - due to target not in $(targets)
 177 # (1) PHONY targets are always build
 178 # (2) No target, so we better build it
 179 # (3) Prerequisite is newer than target
 180 # (4) The command line stored in the file named dir/.target.cmd
 181 #     differed from actual command line. This happens when compiler
 182 #     options changes
 183 # (5) No dir/.target.cmd file (used to store command line)
 184 # (6) No dir/.target.cmd file and target not listed in $(targets)
 185 #     This is a good hint that there is a bug in the kbuild file
 186 ifeq ($(KBUILD_VERBOSE),2)
 187 why =                                                                        \
 188     $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
 189         $(if $(wildcard $@),                                                 \
 190             $(if $(strip $(any-prereq)),- due to: $(any-prereq),             \
 191                 $(if $(arg-check),                                           \
 192                     $(if $(cmd_$@),- due to command line change,             \
 193                         $(if $(filter $@, $(targets)),                       \
 194                             - due to missing .cmd file,                      \
 195                             - due to $(notdir $@) not in $$(targets)         \
 196                          )                                                   \
 197                      )                                                       \
 198                  )                                                           \
 199              ),                                                              \
 200              - due to target missing                                         \
 201          )                                                                   \
 202      )
 203
 204 echo-why = $(call escsq, $(strip $(why)))
 205 endif