Kbuild.include 8.26 KB
Newer Older
1 2 3
####
# kbuild: Generic definitions

4
# Convenient constants
5
comma   := ,
6
squote  := '
7 8 9
empty   :=
space   := $(empty) $(empty)

10 11 12 13
###
# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
dot-target = $(dir $@).$(notdir $@)

14 15 16
###
# The temporary file to save gcc -MD generated dependencies must not
# contain a comma
17
depfile = $(subst $(comma),_,$(dot-target).d)
18

19 20 21 22
###
# filename of target with directory and extension stripped
basetarget = $(basename $(notdir $@))

23 24 25 26
###
# Escape single quote for use in echo statements
escsq = $(subst $(squote),'\$(squote)',$1)

27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
###
# filechk is used to check if the content of a generated file is updated.
# Sample usage:
# define filechk_sample
#	echo $KERNELRELEASE
# endef
# version.h : Makefile
#	$(call filechk,sample)
# The rule defined shall write to stdout the content of the new file.
# The existing file will be compared with the new one.
# - If no file exist it is created
# - If the content differ the new file is used
# - If they are equal no change, and no timestamp update
# - stdin is piped in from the first prerequisite ($<) so one has
#   to specify a valid file as first prerequisite (often the kbuild file)
define filechk
	$(Q)set -e;				\
	echo '  CHK     $@';			\
	mkdir -p $(dir $@);			\
	$(filechk_$(1)) < $< > $@.tmp;		\
	if [ -r $@ ] && cmp -s $@ $@.tmp; then	\
		rm -f $@.tmp;			\
	else					\
		echo '  UPD     $@';		\
		mv -f $@.tmp $@;		\
	fi
endef

55
######
56
# gcc support functions
57 58
# See documentation in Documentation/kbuild/makefiles.txt

59
# checker-shell
60
# Usage: option = $(call checker-shell,$(CC)...-o $$OUT,option-ok,otherwise)
61 62
# Exit code chooses option. $$OUT is safe location for needless output.
define checker-shell
63
 $(strip
64 65 66 67 68 69 70 71
  $(shell set -e; \
    DIR=$(KBUILD_EXTMOD); \
    cd $${DIR:-$(objtree)}; \
    OUT=$$PWD/.$$$$.null; \
    if $(1) >/dev/null 2>&1; \
      then echo "$(2)"; \
      else echo "$(3)"; \
    fi; \
72
    rm -f $$OUT))
73
endef
74

75
# as-option
76 77 78
# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
as-option = $(call checker-shell,\
   $(CC) $(CFLAGS) $(1) -c -xassembler /dev/null -o $$OUT,$(1),$(2))
79

80
# as-instr
81 82 83
# Usage: cflags-y += $(call as-instr,instr,option1,option2)
as-instr = $(call checker-shell,\
   printf "$(1)" | $(CC) $(AFLAGS) -c -xassembler -o $$OUT -,$(2),$(3))
84

85
# cc-option
86 87 88
# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
cc-option = $(call checker-shell,\
   $(CC) $(CFLAGS) $(if $(3),$(3),$(1)) -S -xc /dev/null -o $$OUT,$(1),$(2))
89 90

# cc-option-yn
91 92
# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
cc-option-yn = $(call cc-option,"y","n",$(1))
93 94 95 96

# cc-option-align
# Prefix align with either -falign or -malign
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))
102 103 104

# cc-ifversion
# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
105
cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
106

Roland McGrath's avatar
Roland McGrath committed
107 108
# ld-option
# Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
109 110
ld-option = $(call checker-shell,\
   $(CC) $(1) -nostdlib -xc /dev/null -o $$OUT,$(1),$(2))
111 112

######
Roland McGrath's avatar
Roland McGrath committed
113

114 115 116 117 118
# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
# Usage:
# $(Q)$(MAKE) $(build)=dir
build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj

119 120 121
# Prefix -I with $(srctree) if it is not an absolute path,
# add original to the end
addtree = $(if \
122
	$(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
123

124
# Find all -I options and call addtree
125 126
flags = $(foreach o,$($(1)),\
	$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
127

128 129
# echo command.
# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
130
echo-cmd = $(if $($(quiet)cmd_$(1)),\
131 132 133
	echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)

# 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)))
Sam Ravnborg's avatar
Sam Ravnborg committed
138

139
###
140
# if_changed      - execute command if any prerequisite is newer than
141 142 143 144 145 146 147
#                   target, or command line has changed
# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
#                   including used config symbols
# if_changed_rule - as if_changed but execute rule instead
# See Documentation/kbuild/makefiles.txt for more info

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
150 151
arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
                    $(filter-out $(cmd_$@),   $(cmd_$(1))) )
152 153
endif

154 155 156 157
# >'< substitution is for echo to work,
# >$< substitution to preserve $ when reloading .cmd file
# note: when using inline perl scripts [perl -e '...$$t=1;...']
# in $(cmd_xxx) double $$ your perl vars
158 159
make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))

160 161 162 163
# Find any prerequisites that is newer than target or that does not exist.
# PHONY targets skipped in both cases.
any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)

164
# Execute command if command has changed or prerequisite(s) are updated.
165
#
166 167 168 169
if_changed = $(if $(strip $(any-prereq) $(arg-check)),                       \
	@set -e;                                                             \
	$(echo-cmd) $(cmd_$(1));                                             \
	echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
170

171 172
# Execute the command and also postprocess generated .d dependencies file.
#
173 174 175 176 177 178
if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ),                  \
	@set -e;                                                             \
	$(echo-cmd) $(cmd_$(1));                                             \
	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
	rm -f $(depfile);                                                    \
	mv -f $(dot-target).tmp $(dot-target).cmd)
179

180 181
# Will check if $(cmd_foo) changed, or any of the prerequisites changed,
# and if so will execute $(rule_foo).
182
# Usage: $(call if_changed_rule,foo)
183
#
184 185 186 187
if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ),                 \
	@set -e;                                                             \
	$(rule_$(1)))

188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226
###
# why - tell why a a target got build
#       enabled by make V=2
#       Output (listed in the order they are checked):
#          (1) - due to target is PHONY
#          (2) - due to target missing
#          (3) - due to: file1.h file2.h
#          (4) - due to command line change
#          (5) - due to missing .cmd file
#          (6) - due to target not in $(targets)
# (1) PHONY targets are always build
# (2) No target, so we better build it
# (3) Prerequisite is newer than target
# (4) The command line stored in the file named dir/.target.cmd
#     differed from actual command line. This happens when compiler
#     options changes
# (5) No dir/.target.cmd file (used to store command line)
# (6) No dir/.target.cmd file and target not listed in $(targets)
#     This is a good hint that there is a bug in the kbuild file
ifeq ($(KBUILD_VERBOSE),2)
why =                                                                        \
    $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
        $(if $(wildcard $@),                                                 \
            $(if $(strip $(any-prereq)),- due to: $(any-prereq),             \
                $(if $(arg-check),                                           \
                    $(if $(cmd_$@),- due to command line change,             \
                        $(if $(filter $@, $(targets)),                       \
                            - due to missing .cmd file,                      \
                            - due to $(notdir $@) not in $$(targets)         \
                         )                                                   \
                     )                                                       \
                 )                                                           \
             ),                                                              \
             - due to target missing                                         \
         )                                                                   \
     )

echo-why = $(call escsq, $(strip $(why)))
endif