xref: /openbmc/linux/scripts/Kbuild.include (revision 249592bf) 
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 := \#
13
14###
15# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
16dot-target = $(dir $@).$(notdir $@)
17
18###
19# The temporary file to save gcc -MMD generated dependencies must not
20# contain a comma
21depfile = $(subst $(comma),_,$(dot-target).d)
22
23###
24# filename of target with directory and extension stripped
25basetarget = $(basename $(notdir $@))
26
27###
28# real prerequisites without phony targets
29real-prereqs = $(filter-out $(PHONY), $^)
30
31###
32# Escape single quote for use in echo statements
33escsq = $(subst $(squote),'\$(squote)',$1)
34
35###
36# Quote a string to pass it to C files. foo => '"foo"'
37stringify = $(squote)$(quote)$1$(quote)$(squote)
38
39###
40# Easy method for doing a status message
41       kecho := :
42 quiet_kecho := echo
43silent_kecho := :
44kecho := $($(quiet)kecho)
45
46###
47# filechk is used to check if the content of a generated file is updated.
48# Sample usage:
49#
50# filechk_sample = echo $(KERNELRELEASE)
51# version.h: FORCE
52#	$(call filechk,sample)
53#
54# The rule defined shall write to stdout the content of the new file.
55# The existing file will be compared with the new one.
56# - If no file exist it is created
57# - If the content differ the new file is used
58# - If they are equal no change, and no timestamp update
59define filechk
60	$(Q)set -e;						\
61	mkdir -p $(dir $@);					\
62	trap "rm -f $(dot-target).tmp" EXIT;			\
63	{ $(filechk_$(1)); } > $(dot-target).tmp;		\
64	if [ ! -r $@ ] || ! cmp -s $@ $(dot-target).tmp; then	\
65		$(kecho) '  UPD     $@';			\
66		mv -f $(dot-target).tmp $@;			\
67	fi
68endef
69
70###
71# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
72# Usage:
73# $(Q)$(MAKE) $(build)=dir
74build := -f $(srctree)/scripts/Makefile.build obj
75
76###
77# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.dtbinst obj=
78# Usage:
79# $(Q)$(MAKE) $(dtbinst)=dir
80dtbinst := -f $(srctree)/scripts/Makefile.dtbinst obj
81
82###
83# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj=
84# Usage:
85# $(Q)$(MAKE) $(clean)=dir
86clean := -f $(srctree)/scripts/Makefile.clean obj
87
88# echo command.
89# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
90echo-cmd = $(if $($(quiet)cmd_$(1)),\
91	echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
92
93# printing commands
94cmd = @set -e; $(echo-cmd) $(cmd_$(1))
95
96###
97# if_changed      - execute command if any prerequisite is newer than
98#                   target, or command line has changed
99# if_changed_dep  - as if_changed, but uses fixdep to reveal dependencies
100#                   including used config symbols
101# if_changed_rule - as if_changed but execute rule instead
102# See Documentation/kbuild/makefiles.rst for more info
103
104ifneq ($(KBUILD_NOCMDDEP),1)
105# Check if both commands are the same including their order. Result is empty
106# string if equal. User may override this check using make KBUILD_NOCMDDEP=1
107cmd-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \
108                         $(subst $(space),$(space_escape),$(strip $(cmd_$1))))
109else
110cmd-check = $(if $(strip $(cmd_$@)),,1)
111endif
112
113# Replace >$< with >$$< to preserve $ when reloading the .cmd file
114# (needed for make)
115# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
116# (needed for make)
117# Replace >'< with >'\''< to be able to enclose the whole string in '...'
118# (needed for the shell)
119make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
120
121# Find any prerequisites that are newer than target or that do not exist.
122# (This is not true for now; $? should contain any non-existent prerequisites,
123# but it does not work as expected when .SECONDARY is present. This seems a bug
124# of GNU Make.)
125# PHONY targets skipped in both cases.
126newer-prereqs = $(filter-out $(PHONY),$?)
127
128# Execute command if command has changed or prerequisite(s) are updated.
129if_changed = $(if $(newer-prereqs)$(cmd-check),                              \
130	$(cmd);                                                              \
131	printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
132
133# Execute the command and also postprocess generated .d dependencies file.
134if_changed_dep = $(if $(newer-prereqs)$(cmd-check),$(cmd_and_fixdep),@:)
135
136cmd_and_fixdep =                                                             \
137	$(cmd);                                                              \
138	scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\
139	rm -f $(depfile)
140
141# Usage: $(call if_changed_rule,foo)
142# Will check if $(cmd_foo) or any of the prerequisites changed,
143# and if so will execute $(rule_foo).
144if_changed_rule = $(if $(newer-prereqs)$(cmd-check),$(rule_$(1)),@:)
145
146###
147# why - tell why a target got built
148#       enabled by make V=2
149#       Output (listed in the order they are checked):
150#          (1) - due to target is PHONY
151#          (2) - due to target missing
152#          (3) - due to: file1.h file2.h
153#          (4) - due to command line change
154#          (5) - due to missing .cmd file
155#          (6) - due to target not in $(targets)
156# (1) PHONY targets are always build
157# (2) No target, so we better build it
158# (3) Prerequisite is newer than target
159# (4) The command line stored in the file named dir/.target.cmd
160#     differed from actual command line. This happens when compiler
161#     options changes
162# (5) No dir/.target.cmd file (used to store command line)
163# (6) No dir/.target.cmd file and target not listed in $(targets)
164#     This is a good hint that there is a bug in the kbuild file
165ifeq ($(KBUILD_VERBOSE),2)
166why =                                                                        \
167    $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
168        $(if $(wildcard $@),                                                 \
169            $(if $(newer-prereqs),- due to: $(newer-prereqs),                \
170                $(if $(cmd-check),                                           \
171                    $(if $(cmd_$@),- due to command line change,             \
172                        $(if $(filter $@, $(targets)),                       \
173                            - due to missing .cmd file,                      \
174                            - due to $(notdir $@) not in $$(targets)         \
175                         )                                                   \
176                     )                                                       \
177                 )                                                           \
178             ),                                                              \
179             - due to target missing                                         \
180         )                                                                   \
181     )
182
183echo-why = $(call escsq, $(strip $(why)))
184endif
185
186###############################################################################
187#
188# When a Kconfig string contains a filename, it is suitable for
189# passing to shell commands. It is surrounded by double-quotes, and
190# any double-quotes or backslashes within it are escaped by
191# backslashes.
192#
193# This is no use for dependencies or $(wildcard). We need to strip the
194# surrounding quotes and the escaping from quotes and backslashes, and
195# we *do* need to escape any spaces in the string. So, for example:
196#
197# Usage: $(eval $(call config_filename,FOO))
198#
199# Defines FOO_FILENAME based on the contents of the CONFIG_FOO option,
200# transformed as described above to be suitable for use within the
201# makefile.
202#
203# Also, if the filename is a relative filename and exists in the source
204# tree but not the build tree, define FOO_SRCPREFIX as $(srctree)/ to
205# be prefixed to *both* command invocation and dependencies.
206#
207# Note: We also print the filenames in the quiet_cmd_foo text, and
208# perhaps ought to have a version specially escaped for that purpose.
209# But it's only cosmetic, and $(patsubst "%",%,$(CONFIG_FOO)) is good
210# enough.  It'll strip the quotes in the common case where there's no
211# space and it's a simple filename, and it'll retain the quotes when
212# there's a space. There are some esoteric cases in which it'll print
213# the wrong thing, but we don't really care. The actual dependencies
214# and commands *do* get it right, with various combinations of single
215# and double quotes, backslashes and spaces in the filenames.
216#
217###############################################################################
218#
219define config_filename
220ifneq ($$(CONFIG_$(1)),"")
221$(1)_FILENAME := $$(subst \\,\,$$(subst \$$(quote),$$(quote),$$(subst $$(space_escape),\$$(space),$$(patsubst "%",%,$$(subst $$(space),$$(space_escape),$$(CONFIG_$(1)))))))
222ifneq ($$(patsubst /%,%,$$(firstword $$($(1)_FILENAME))),$$(firstword $$($(1)_FILENAME)))
223else
224ifeq ($$(wildcard $$($(1)_FILENAME)),)
225ifneq ($$(wildcard $$(srctree)/$$($(1)_FILENAME)),)
226$(1)_SRCPREFIX := $(srctree)/
227endif
228endif
229endif
230endif
231endef
232#
233###############################################################################
234
235# delete partially updated (i.e. corrupted) files on error
236.DELETE_ON_ERROR:
237
238# do not delete intermediate files automatically
239.SECONDARY:
240