LXR linux/scripts/Kbuild.include

   1####
   2# kbuild: Generic definitions
   3
   4# Convenient variables
   5comma   := ,
   6squote  := '
   7empty   :=
   8space   := $(empty) $(empty)
   9
  10###
  11# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
  12dot-target = $(dir $@).$(notdir $@)
  13
  14###
  15# The temporary file to save gcc -MD generated dependencies must not
  16# contain a comma
  17depfile = $(subst $(comma),_,$(dot-target).d)
  18
  19###
  20# filename of target with directory and extension stripped
  21basetarget = $(basename $(notdir $@))
  22
  23###
  24# Escape single quote for use in echo statements
  25escsq = $(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     $@'
  44silent_chk_filechk = :
  45       upd_filechk = :
  46 quiet_upd_filechk = echo '  UPD     $@'
  47silent_upd_filechk = :
  48
  49define 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
  60endef
  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
  70cc-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
  78TMPOUT := $(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.
  84try-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
  95as-option = $(call try-run,\
  96        $(CC) $(KBUILD_CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2))
  97
  98# as-instr
  99# Usage: cflags-y += $(call as-instr,instr,option1,option2)
 100
 101as-instr = $(call try-run,\
 102        echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
 103
 104# cc-option
 105# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
 106
 107cc-option = $(call try-run,\
 108        $(CC) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",$(1),$(2))
 109
 110# cc-option-yn
 111# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
 112cc-option-yn = $(call try-run,\
 113        $(CC) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$TMP",y,n)
 114
 115# cc-option-align
 116# Prefix align with either -falign or -malign
 117cc-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)
 122cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
 123
 124# cc-fullversion
 125# Usage gcc-ver := $(call cc-fullversion)
 126cc-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)
 131cc-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)
 135ld-option = $(call try-run,\
 136        $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
 137
 138######
 139
 140###
 141# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
 142# Usage:
 143# $(Q)$(MAKE) $(build)=dir
 144build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
 145
 146# Prefix -I with $(srctree) if it is not an absolute path.
 147addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
 148
 149# Find all -I options and call addtree
 150flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
 151
 152# echo command.
 153# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
 154echo-cmd = $(if $($(quiet)cmd_$(1)),\
 155        echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
 156
 157# printing commands
 158cmd = @$(echo-cmd) $(cmd_$(1))
 159
 160# Add $(obj)/ for paths that are not absolute
 161objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
 162
 163###
 164# if_changed      - execute command if any prerequisite is newer than
 165#                   target, or command line has changed
 166# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
 167#                   including used config symbols
 168# if_changed_rule - as if_changed but execute rule instead
 169# See Documentation/kbuild/makefiles.txt for more info
 170
 171ifneq ($(KBUILD_NOCMDDEP),1)
 172# Check if both arguments has same arguments. Result is empty string if equal.
 173# User may override this check using make KBUILD_NOCMDDEP=1
 174arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
 175                    $(filter-out $(cmd_$@),   $(cmd_$(1))) )
 176endif
 177
 178# >'< substitution is for echo to work,
 179# >$< substitution to preserve $ when reloading .cmd file
 180# note: when using inline perl scripts [perl -e '...$$t=1;...']
 181# in $(cmd_xxx) double $$ your perl vars
 182make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(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.
 186any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
 187
 188# Execute command if command has changed or prerequisite(s) are updated.
 189#
 190if_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.
 196if_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).
 206if_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
 229ifeq ($(KBUILD_VERBOSE),2)
 230why =                                                                        \
 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
 247echo-why = $(call escsq, $(strip $(why)))
 248endif
 249