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 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 # output directory for tests below
  60 TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
  61
  62 # try-run
  63 # Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
  64 # Exit code chooses option. "$$TMP" is can be used as temporary file and
  65 # is automatically cleaned up.
  66 try-run = $(shell set -e;               \
  67         TMP="$(TMPOUT).$$$$.tmp";       \
  68         if ($(1)) >/dev/null 2>&1;      \
  69         then echo "$(2)";               \
  70         else echo "$(3)";               \
  71         fi;                             \
  72         rm -f "$$TMP")
  73
  74 # as-option
  75 # Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
  76
  77 as-option = $(call try-run,\
  78         $(CC) $(CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2))
  79
  80 # as-instr
  81 # Usage: cflags-y += $(call as-instr,instr,option1,option2)
  82
  83 as-instr = $(call try-run,\
  84         echo -e "$(1)" | $(CC) $(AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
  85
  86 # cc-option
  87 # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
  88
  89 cc-option = $(call try-run,\
  90         $(CC) $(CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",$(1),$(2))
  91
  92 # cc-option-yn
  93 # Usage: flag := $(call cc-option-yn,-march=winchip-c6)
  94 cc-option-yn = $(call try-run,\
  95         $(CC) $(CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",y,n)
  96
  97 # cc-option-align
  98 # Prefix align with either -falign or -malign
  99 cc-option-align = $(subst -functions=0,,\
 100         $(call cc-option,-falign-functions=0,-malign-functions=0))
 101
 102 # cc-version
 103 # Usage gcc-ver := $(call cc-version,$(CC))
 104 cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
 105
 106 # cc-ifversion
 107 # Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
 108 cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
 109
 110 # ld-option
 111 # Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
 112 ld-option = $(call try-run,\
 113         $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
 114
 115 ######
 116
 117 ###
 118 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
 119 # Usage:
 120 # $(Q)$(MAKE) $(build)=dir
 121 build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
 122
 123 # Prefix -I with $(srctree) if it is not an absolute path.
 124 addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
 125
 126 # Find all -I options and call addtree
 127 flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
 128
 129 # echo command.
 130 # Short version is used, if $(quiet) equals `quiet_', otherwise full one.
 131 echo-cmd = $(if $($(quiet)cmd_$(1)),\
 132         echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
 133
 134 # printing commands
 135 cmd = @$(echo-cmd) $(cmd_$(1))
 136
 137 # Add $(obj)/ for paths that are not absolute
 138 objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
 139
 140 ###
 141 # if_changed      - execute command if any prerequisite is newer than
 142 #                   target, or command line has changed
 143 # if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
 144 #                   including used config symbols
 145 # if_changed_rule - as if_changed but execute rule instead
 146 # See Documentation/kbuild/makefiles.txt for more info
 147
 148 ifneq ($(KBUILD_NOCMDDEP),1)
 149 # Check if both arguments has same arguments. Result is empty string if equal.
 150 # User may override this check using make KBUILD_NOCMDDEP=1
 151 arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
 152                     $(filter-out $(cmd_$@),   $(cmd_$(1))) )
 153 endif
 154
 155 # >'< substitution is for echo to work,
 156 # >$< substitution to preserve $ when reloading .cmd file
 157 # note: when using inline perl scripts [perl -e '...$$t=1;...']
 158 # in $(cmd_xxx) double $$ your perl vars
 159 make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
 160
 161 # Find any prerequisites that is newer than target or that does not exist.
 162 # PHONY targets skipped in both cases.
 163 any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
 164
 165 # Execute command if command has changed or prerequisite(s) are updated.
 166 #
 167 if_changed = $(if $(strip $(any-prereq) $(arg-check)),                       \
 168         @set -e;                                                             \
 169         $(echo-cmd) $(cmd_$(1));                                             \
 170         echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
 171
 172 # Execute the command and also postprocess generated .d dependencies file.
 173 if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ),                  \
 174         @set -e;                                                             \
 175         $(echo-cmd) $(cmd_$(1));                                             \
 176         scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
 177         rm -f $(depfile);                                                    \
 178         mv -f $(dot-target).tmp $(dot-target).cmd)
 179
 180 # Usage: $(call if_changed_rule,foo)
 181 # Will check if $(cmd_foo) or any of the prerequisites changed,
 182 # and if so will execute $(rule_foo).
 183 if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ),                 \
 184         @set -e;                                                             \
 185         $(rule_$(1)))
 186
 187 ###
 188 # why - tell why a a target got build
 189 #       enabled by make V=2
 190 #       Output (listed in the order they are checked):
 191 #          (1) - due to target is PHONY
 192 #          (2) - due to target missing
 193 #          (3) - due to: file1.h file2.h
 194 #          (4) - due to command line change
 195 #          (5) - due to missing .cmd file
 196 #          (6) - due to target not in $(targets)
 197 # (1) PHONY targets are always build
 198 # (2) No target, so we better build it
 199 # (3) Prerequisite is newer than target
 200 # (4) The command line stored in the file named dir/.target.cmd
 201 #     differed from actual command line. This happens when compiler
 202 #     options changes
 203 # (5) No dir/.target.cmd file (used to store command line)
 204 # (6) No dir/.target.cmd file and target not listed in $(targets)
 205 #     This is a good hint that there is a bug in the kbuild file
 206 ifeq ($(KBUILD_VERBOSE),2)
 207 why =                                                                        \
 208     $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
 209         $(if $(wildcard $@),                                                 \
 210             $(if $(strip $(any-prereq)),- due to: $(any-prereq),             \
 211                 $(if $(arg-check),                                           \
 212                     $(if $(cmd_$@),- due to command line change,             \
 213                         $(if $(filter $@, $(targets)),                       \
 214                             - due to missing .cmd file,                      \
 215                             - due to $(notdir $@) not in $$(targets)         \
 216                          )                                                   \
 217                      )                                                       \
 218                  )                                                           \
 219              ),                                                              \
 220              - due to target missing                                         \
 221          )                                                                   \
 222      )
 223
 224 echo-why = $(call escsq, $(strip $(why)))
 225 endif