xref: /openbmc/linux/scripts/Kbuild.include (revision f15cbe6f) 
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) -S -xc /dev/null -o "$$TMP",$(1),$(2))
109
110# cc-option-yn
111# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
112cc-option-yn = $(call try-run,\
113	$(CC) $(KBUILD_CFLAGS) $(1) -S -xc /dev/null -o "$$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