scripts/Kbuild.include

   1 ####
   2 # kbuild: Generic definitions
   3
   4 # Convenient 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        chk_filechk = :
  43  quiet_chk_filechk = echo '  CHK     $@'
  44 silent_chk_filechk = :
  45        upd_filechk = :
  46  quiet_upd_filechk = echo '  UPD     $@'
  47 silent_upd_filechk = :
  48
  49 define 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
  60 endef
  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
  70 cc-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
  78 TMPOUT := $(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.
  84 try-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
  95 as-option = $(call try-run,\
  96         $(CC) $(KBUILD_CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2))
  97
  98 # as-instr
  99 # Usage: cflags-y += $(call as-instr,instr,option1,option2)
 100
 101 as-instr = $(call try-run,\
 102         echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
 103
 104 # cc-option
 105 # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
 106
 107 cc-option = $(call try-run,\
 108         $(CC) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",$(1),$(2))
 109
 110 # cc-option-yn
 111 # Usage: flag := $(call cc-option-yn,-march=winchip-c6)
 112 cc-option-yn = $(call try-run,\
 113         $(CC) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",y,n)
 114
 115 # cc-option-align
 116 # Prefix align with either -falign or -malign
 117 cc-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)
 122 cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
 123
 124 # cc-fullversion
 125 # Usage gcc-ver := $(call cc-fullversion)
 126 cc-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)
 131 cc-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)
 135 ld-option = $(call try-run,\
 136         $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
 137
 138 ######
 139
 140 ###
 141 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
 142 # Usage:
 143 # $(Q)$(MAKE) $(build)=dir
 144 build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
 145
 146 # Prefix -I with $(srctree) if it is not an absolute path.
 147 addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
 148
 149 # Find all -I options and call addtree
 150 flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
 151
 152 # echo command.
 153 # Short version is used, if $(quiet) equals `quiet_', otherwise full one.
 154 echo-cmd = $(if $($(quiet)cmd_$(1)),\
 155         echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
 156
 157 # printing commands
 158 cmd = @$(echo-cmd) $(cmd_$(1))
 159
 160 # Add $(obj)/ for paths that are not absolute
 161 objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
 162
 163 ###
 164 # if_changed      - execute command if any prerequisite is newer than
 165 #                   target, or command line has changed
 166 # if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
 167 #                   including used config symbols
 168 # if_changed_rule - as if_changed but execute rule instead
 169 # See Documentation/kbuild/makefiles.txt for more info
 170
 171 ifneq ($(KBUILD_NOCMDDEP),1)
 172 # Check if both arguments has same arguments. Result is empty string if equal.
 173 # User may override this check using make KBUILD_NOCMDDEP=1
 174 arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
 175                     $(filter-out $(cmd_$@),   $(cmd_$(1))) )
 176 endif
 177
 178 # >'< substitution is for echo to work,
 179 # >$< substitution to preserve $ when reloading .cmd file
 180 # note: when using inline perl scripts [perl -e '...$$t=1;...']
 181 # in $(cmd_xxx) double $$ your perl vars
 182 make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(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.
 186 any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
 187
 188 # Execute command if command has changed or prerequisite(s) are updated.
 189 #
 190 if_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.
 196 if_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).
 206 if_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
 229 ifeq ($(KBUILD_VERBOSE),2)
 230 why =                                                                        \
 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
 247 echo-why = $(call escsq, $(strip $(why)))
 248 endif