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)
42define 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
53endef
54
55######
56# gcc support functions
57# See documentation in Documentation/kbuild/makefiles.txt
58
59# output directory for tests below
60TMPOUT := $(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.
66try-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
77as-option = $(call try-run,\
78	$(CC) $(CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2))
79
80# as-instr
81# Usage: cflags-y += $(call as-instr,instr,option1,option2)
82
83as-instr = $(call try-run,\
84	echo -e "$(1)" | $(CC) $(AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
85
86# cc-option
87# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
88
89cc-option = $(call try-run,\
90	$(CC) $(CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",$(1),$(2))
91
92# cc-option-yn
93# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
94cc-option-yn = $(call try-run,\
95	$(CC) $(CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",y,n)
96
97# cc-option-align
98# Prefix align with either -falign or -malign
99cc-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))
104cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
105
106# cc-ifversion
107# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
108cc-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)
112ld-option = $(call try-run,\
113	$(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
114
115######
116
117###
118# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
119# Usage:
120# $(Q)$(MAKE) $(build)=dir
121build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
122
123# Prefix -I with $(srctree) if it is not an absolute path.
124addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
125
126# Find all -I options and call addtree
127flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
128
129# echo command.
130# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
131echo-cmd = $(if $($(quiet)cmd_$(1)),\
132	echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
133
134# printing commands
135cmd = @$(echo-cmd) $(cmd_$(1))
136
137# Add $(obj)/ for paths that are not absolute
138objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
139
140###
141# if_changed      - execute command if any prerequisite is newer than
142#                   target, or command line has changed
143# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
144#                   including used config symbols
145# if_changed_rule - as if_changed but execute rule instead
146# See Documentation/kbuild/makefiles.txt for more info
147
148ifneq ($(KBUILD_NOCMDDEP),1)
149# Check if both arguments has same arguments. Result is empty string if equal.
150# User may override this check using make KBUILD_NOCMDDEP=1
151arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
152                    $(filter-out $(cmd_$@),   $(cmd_$(1))) )
153endif
154
155# >'< substitution is for echo to work,
156# >$< substitution to preserve $ when reloading .cmd file
157# note: when using inline perl scripts [perl -e '...$$t=1;...']
158# in $(cmd_xxx) double $$ your perl vars
159make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(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.
163any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
164
165# Execute command if command has changed or prerequisite(s) are updated.
166#
167if_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.
173if_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).
183if_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
206ifeq ($(KBUILD_VERBOSE),2)
207why =                                                                        \
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
224echo-why = $(call escsq, $(strip $(why)))
225endif
226