1####
2# kbuild: Generic definitions
3
4# Convinient variables
5comma   := ,
6squote  := '
7quote   := "
8empty   :=
9space   := $(empty) $(empty)
10
11###
12# The temporary file to save gcc -MD generated dependencies must not
13# contain a comma
14depfile = $(subst $(comma),_,$(@D)/.$(@F).d)
15
16###
17# Escape single quote for use in echo statements
18escsq = $(subst $(squote),'\$(squote)',$1)
19
20###
21# filechk is used to check if the content of a generated file is updated.
22# Sample usage:
23# define filechk_sample
24#	echo $KERNELRELEASE
25# endef
26# version.h : Makefile
27#	$(call filechk,sample)
28# The rule defined shall write to stdout the content of the new file.
29# The existing file will be compared with the new one.
30# - If no file exist it is created
31# - If the content differ the new file is used
32# - If they are equal no change, and no timestamp update
33# - stdin is piped in from the first prerequisite ($<) so one has
34#   to specify a valid file as first prerequisite (often the kbuild file)
35define filechk
36	$(Q)set -e;				\
37	echo '  CHK     $@';			\
38	mkdir -p $(dir $@);			\
39	$(filechk_$(1)) < $< > $@.tmp;		\
40	if [ -r $@ ] && cmp -s $@ $@.tmp; then	\
41		rm -f $@.tmp;			\
42	else					\
43		echo '  UPD     $@';		\
44		mv -f $@.tmp $@;		\
45	fi
46endef
47
48######
49# gcc support functions
50# See documentation in Documentation/kbuild/makefiles.txt
51
52# as-option
53# Usage: cflags-y += $(call as-option, -Wa$(comma)-isa=foo,)
54
55as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \
56	     -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \
57	     else echo "$(2)"; fi ;)
58
59# cc-option
60# Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586)
61
62cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
63             > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
64
65# hostcc-option
66# Usage: hostcflags-y += $(call hostcc-option, -march=winchip-c6, -march=i586)
67
68hostcc-option = $(shell if $(HOSTCC) $(HOSTCFLAGS) $(1) -S -o /dev/null -xc /dev/null \
69             > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
70
71# cc-option-yn
72# Usage: flag := $(call cc-option-yn, -march=winchip-c6)
73cc-option-yn = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
74                > /dev/null 2>&1; then echo "y"; else echo "n"; fi;)
75
76# cc-option-align
77# Prefix align with either -falign or -malign
78cc-option-align = $(subst -functions=0,,\
79	$(call cc-option,-falign-functions=0,-malign-functions=0))
80
81# cc-version
82# Usage gcc-ver := $(call cc-version, $(CC))
83cc-version = $(shell PATH="$(PATH)" $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh \
84              $(if $(1), $(1), $(CC)))
85
86# cc-ifversion
87# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
88cc-ifversion = $(shell if [ $(call cc-version, $(CC)) $(1) $(2) ]; then \
89                       echo $(3); fi;)
90
91###
92# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
93# Usage:
94# $(Q)$(MAKE) $(build)=dir
95build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
96
97# Prefix -I with $(srctree) if it is not an absolute path
98addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
99# Find all -I options and call addtree
100flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
101
102# If quiet is set, only print short version of command
103cmd = @$(echo-cmd) $(cmd_$(1))
104
105# Add $(obj)/ for paths that is not absolute
106objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
107
108###
109# if_changed      - execute command if any prerequisite is newer than
110#                   target, or command line has changed
111# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
112#                   including used config symbols
113# if_changed_rule - as if_changed but execute rule instead
114# See Documentation/kbuild/makefiles.txt for more info
115
116ifneq ($(KBUILD_NOCMDDEP),1)
117# Check if both arguments has same arguments. Result in empty string if equal
118# User may override this check using make KBUILD_NOCMDDEP=1
119arg-check = $(strip $(filter-out $(1), $(2)) $(filter-out $(2), $(1)) )
120endif
121
122# echo command. Short version is $(quiet) equals quiet, otherwise full command
123echo-cmd = $(if $($(quiet)cmd_$(1)), \
124	echo '  $(call escsq,$($(quiet)cmd_$(1)))';)
125
126make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
127
128# function to only execute the passed command if necessary
129# >'< substitution is for echo to work, >$< substitution to preserve $ when reloading .cmd file
130# note: when using inline perl scripts [perl -e '...$$t=1;...'] in $(cmd_xxx) double $$ your perl vars
131#
132if_changed = $(if $(strip $(filter-out $(PHONY),$?)          \
133		$(call arg-check, $(cmd_$(1)), $(cmd_$@)) ), \
134	@set -e; \
135	$(echo-cmd) $(cmd_$(1)); \
136	echo 'cmd_$@ := $(make-cmd)' > $(@D)/.$(@F).cmd)
137
138# execute the command and also postprocess generated .d dependencies
139# file
140if_changed_dep = $(if $(strip $(filter-out $(PHONY),$?)  \
141		$(filter-out FORCE $(wildcard $^),$^)    \
142	$(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),     \
143	@set -e; \
144	$(echo-cmd) $(cmd_$(1)); \
145	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(@D)/.$(@F).tmp; \
146	rm -f $(depfile); \
147	mv -f $(@D)/.$(@F).tmp $(@D)/.$(@F).cmd)
148
149# Usage: $(call if_changed_rule,foo)
150# will check if $(cmd_foo) changed, or any of the prequisites changed,
151# and if so will execute $(rule_foo)
152if_changed_rule = $(if $(strip $(filter-out $(PHONY),$?)            \
153			$(call arg-check, $(cmd_$(1)), $(cmd_$@)) ),\
154			@set -e; \
155			$(rule_$(1)))
156