xref: /openbmc/linux/scripts/Kbuild.include (revision 18da174d) 
1# SPDX-License-Identifier: GPL-2.0
2####
3# kbuild: Generic definitions
4
5# Convenient variables
6comma   := ,
7quote   := "
8squote  := '
9empty   :=
10space   := $(empty) $(empty)
11space_escape := _-_SPACE_-_
12pound := \#
13define newline
14
15
16endef
17
18###
19# Comparison macros.
20# Usage: $(call test-lt, $(CONFIG_LLD_VERSION), 150000)
21#
22# Use $(intcmp ...) if supported. (Make >= 4.4)
23# Otherwise, fall back to the 'test' shell command.
24ifeq ($(intcmp 1,0,,,y),y)
25test-ge = $(intcmp $(strip $1)0, $(strip $2)0,,y,y)
26test-gt = $(intcmp $(strip $1)0, $(strip $2)0,,,y)
27else
28test-ge = $(shell test $(strip $1)0 -ge $(strip $2)0 && echo y)
29test-gt = $(shell test $(strip $1)0 -gt $(strip $2)0 && echo y)
30endif
31test-le = $(call test-ge, $2, $1)
32test-lt = $(call test-gt, $2, $1)
33
34###
35# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
36dot-target = $(dir $@).$(notdir $@)
37
38###
39# Name of target with a '.tmp_' as filename prefix. foo/bar.o => foo/.tmp_bar.o
40tmp-target = $(dir $@).tmp_$(notdir $@)
41
42###
43# The temporary file to save gcc -MMD generated dependencies must not
44# contain a comma
45depfile = $(subst $(comma),_,$(dot-target).d)
46
47###
48# filename of target with directory and extension stripped
49basetarget = $(basename $(notdir $@))
50
51###
52# real prerequisites without phony targets
53real-prereqs = $(filter-out $(PHONY), $^)
54
55###
56# Escape single quote for use in echo statements
57escsq = $(subst $(squote),'\$(squote)',$1)
58
59###
60# Quote a string to pass it to C files. foo => '"foo"'
61stringify = $(squote)$(quote)$1$(quote)$(squote)
62
63###
64# The path to Kbuild or Makefile. Kbuild has precedence over Makefile.
65kbuild-dir = $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
66kbuild-file = $(or $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Makefile)
67
68###
69# Read a file, replacing newlines with spaces
70#
71# Make 4.2 or later can read a file by using its builtin function.
72ifneq ($(filter-out 3.% 4.0 4.1, $(MAKE_VERSION)),)
73read-file = $(subst $(newline),$(space),$(file < $1))
74else
75read-file = $(shell cat $1 2>/dev/null)
76endif
77
78###
79# Easy method for doing a status message
80       kecho := :
81 quiet_kecho := echo
82silent_kecho := :
83kecho := $($(quiet)kecho)
84
85###
86# filechk is used to check if the content of a generated file is updated.
87# Sample usage:
88#
89# filechk_sample = echo $(KERNELRELEASE)
90# version.h: FORCE
91#	$(call filechk,sample)
92#
93# The rule defined shall write to stdout the content of the new file.
94# The existing file will be compared with the new one.
95# - If no file exist it is created
96# - If the content differ the new file is used
97# - If they are equal no change, and no timestamp update
98define filechk
99	$(check-FORCE)
100	$(Q)set -e;						\
101	mkdir -p $(dir $@);					\
102	trap "rm -f $(tmp-target)" EXIT;			\
103	{ $(filechk_$(1)); } > $(tmp-target);			\
104	if [ ! -r $@ ] || ! cmp -s $@ $(tmp-target); then	\
105		$(kecho) '  UPD     $@';			\
106		mv -f $(tmp-target) $@;				\
107	fi
108endef
109
110###
111# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
112# Usage:
113# $(Q)$(MAKE) $(build)=dir
114build := -f $(srctree)/scripts/Makefile.build obj
115
116###
117# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.dtbinst obj=
118# Usage:
119# $(Q)$(MAKE) $(dtbinst)=dir
120dtbinst := -f $(srctree)/scripts/Makefile.dtbinst obj
121
122###
123# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=
124# Usage:
125# $(Q)$(MAKE) $(clean)=dir
126clean := -f $(srctree)/scripts/Makefile.clean obj
127
128# pring log
129#
130# If quiet is "silent_", print nothing and sink stdout
131# If quiet is "quiet_", print short log
132# If quiet is empty, print short log and whole command
133silent_log_print = exec >/dev/null;
134 quiet_log_print = $(if $(quiet_cmd_$1), echo '  $(call escsq,$(quiet_cmd_$1)$(why))';)
135       log_print = echo '$(pound) $(call escsq,$(or $(quiet_cmd_$1),cmd_$1 $@)$(why))'; \
136                   echo '  $(call escsq,$(cmd_$1))';
137
138# Delete the target on interruption
139#
140# GNU Make automatically deletes the target if it has already been changed by
141# the interrupted recipe. So, you can safely stop the build by Ctrl-C (Make
142# will delete incomplete targets), and resume it later.
143#
144# However, this does not work when the stderr is piped to another program, like
145#  $ make >&2 | tee log
146# Make dies with SIGPIPE before cleaning the targets.
147#
148# To address it, we clean the target in signal traps.
149#
150# Make deletes the target when it catches SIGHUP, SIGINT, SIGQUIT, SIGTERM.
151# So, we cover them, and also SIGPIPE just in case.
152#
153# Of course, this is unneeded for phony targets.
154delete-on-interrupt = \
155	$(if $(filter-out $(PHONY), $@), \
156		$(foreach sig, HUP INT QUIT TERM PIPE, \
157			trap 'rm -f $@; trap - $(sig); kill -s $(sig) $$$$' $(sig);))
158
159# print and execute commands
160cmd = @$(if $(cmd_$(1)),set -e; $($(quiet)log_print) $(delete-on-interrupt) $(cmd_$(1)),:)
161
162###
163# if_changed      - execute command if any prerequisite is newer than
164#                   target, or command line has changed
165# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
166#                   including used config symbols
167# if_changed_rule - as if_changed but execute rule instead
168# See Documentation/kbuild/makefiles.rst for more info
169
170ifneq ($(KBUILD_NOCMDDEP),1)
171# Check if both commands are the same including their order. Result is empty
172# string if equal. User may override this check using make KBUILD_NOCMDDEP=1
173# If the target does not exist, the *.cmd file should not be included so
174# $(savedcmd_$@) gets empty. Then, target will be built even if $(newer-prereqs)
175# happens to become empty.
176cmd-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(savedcmd_$@))), \
177                         $(subst $(space),$(space_escape),$(strip $(cmd_$1))))
178else
179# We still need to detect missing targets.
180cmd-check = $(if $(strip $(savedcmd_$@)),,1)
181endif
182
183# Replace >$< with >$$< to preserve $ when reloading the .cmd file
184# (needed for make)
185# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
186# (needed for make)
187# Replace >'< with >'\''< to be able to enclose the whole string in '...'
188# (needed for the shell)
189make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
190
191# Find any prerequisites that are newer than target or that do not exist.
192# PHONY targets skipped in both cases.
193# If there is no prerequisite other than phony targets, $(newer-prereqs) becomes
194# empty even if the target does not exist. cmd-check saves this corner case.
195newer-prereqs = $(filter-out $(PHONY),$?)
196
197# It is a typical mistake to forget the FORCE prerequisite. Check it here so
198# no more breakage will slip in.
199check-FORCE = $(if $(filter FORCE, $^),,$(warning FORCE prerequisite is missing))
200
201if-changed-cond = $(newer-prereqs)$(cmd-check)$(check-FORCE)
202
203# Execute command if command has changed or prerequisite(s) are updated.
204if_changed = $(if $(if-changed-cond),$(cmd_and_savecmd),@:)
205
206cmd_and_savecmd =                                                            \
207	$(cmd);                                                              \
208	printf '%s\n' 'savedcmd_$@ := $(make-cmd)' > $(dot-target).cmd
209
210# Execute the command and also postprocess generated .d dependencies file.
211if_changed_dep = $(if $(if-changed-cond),$(cmd_and_fixdep),@:)
212
213cmd_and_fixdep =                                                             \
214	$(cmd);                                                              \
215	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\
216	rm -f $(depfile)
217
218# Usage: $(call if_changed_rule,foo)
219# Will check if $(cmd_foo) or any of the prerequisites changed,
220# and if so will execute $(rule_foo).
221if_changed_rule = $(if $(if-changed-cond),$(rule_$(1)),@:)
222
223###
224# why - tell why a target got built
225#       enabled by make V=2
226#       Output (listed in the order they are checked):
227#          (1) - due to target is PHONY
228#          (2) - due to target missing
229#          (3) - due to: file1.h file2.h
230#          (4) - due to command line change
231#          (5) - due to missing .cmd file
232#          (6) - due to target not in $(targets)
233# (1) PHONY targets are always build
234# (2) No target, so we better build it
235# (3) Prerequisite is newer than target
236# (4) The command line stored in the file named dir/.target.cmd
237#     differed from actual command line. This happens when compiler
238#     options changes
239# (5) No dir/.target.cmd file (used to store command line)
240# (6) No dir/.target.cmd file and target not listed in $(targets)
241#     This is a good hint that there is a bug in the kbuild file
242ifneq ($(findstring 2, $(KBUILD_VERBOSE)),)
243_why =                                                                        \
244    $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
245        $(if $(wildcard $@),                                                 \
246            $(if $(newer-prereqs),- due to: $(newer-prereqs),                \
247                $(if $(cmd-check),                                           \
248                    $(if $(savedcmd_$@),- due to command line change,        \
249                        $(if $(filter $@, $(targets)),                       \
250                            - due to missing .cmd file,                      \
251                            - due to $(notdir $@) not in $$(targets)         \
252                         )                                                   \
253                     )                                                       \
254                 )                                                           \
255             ),                                                              \
256             - due to target missing                                         \
257         )                                                                   \
258     )
259
260why = $(space)$(strip $(_why))
261endif
262
263###############################################################################
264
265# delete partially updated (i.e. corrupted) files on error
266.DELETE_ON_ERROR:
267
268# do not delete intermediate files automatically
269#
270# .NOTINTERMEDIATE is more correct, but only available on newer Make versions.
271# Make 4.4 introduced .NOTINTERMEDIATE, and it appears in .FEATURES, but the
272# global .NOTINTERMEDIATE does not work. We can use it on Make > 4.4.
273# Use .SECONDARY for older Make versions, but "newer-prereq" cannot detect
274# deleted files.
275ifneq ($(and $(filter notintermediate, $(.FEATURES)),$(filter-out 4.4,$(MAKE_VERSION))),)
276.NOTINTERMEDIATE:
277else
278.SECONDARY:
279endif
280