scripts/Kbuild.include

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