Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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)
104cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
105
106# cc-fullversion
107# Usage gcc-ver := $(call cc-fullversion)
108cc-fullversion = $(shell $(CONFIG_SHELL) \
109 $(srctree)/scripts/gcc-version.sh -p $(CC))
110
111# cc-ifversion
112# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
113cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
114
115# ld-option
116# Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
117ld-option = $(call try-run,\
118 $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
119
120######
121
122###
123# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
124# Usage:
125# $(Q)$(MAKE) $(build)=dir
126build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
127
128# Prefix -I with $(srctree) if it is not an absolute path.
129addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
130
131# Find all -I options and call addtree
132flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
133
134# echo command.
135# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
136echo-cmd = $(if $($(quiet)cmd_$(1)),\
137 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
138
139# printing commands
140cmd = @$(echo-cmd) $(cmd_$(1))
141
142# Add $(obj)/ for paths that are not absolute
143objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
144
145###
146# if_changed - execute command if any prerequisite is newer than
147# target, or command line has changed
148# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
149# including used config symbols
150# if_changed_rule - as if_changed but execute rule instead
151# See Documentation/kbuild/makefiles.txt for more info
152
153ifneq ($(KBUILD_NOCMDDEP),1)
154# Check if both arguments has same arguments. Result is empty string if equal.
155# User may override this check using make KBUILD_NOCMDDEP=1
156arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
157 $(filter-out $(cmd_$@), $(cmd_$(1))) )
158endif
159
160# >'< substitution is for echo to work,
161# >$< substitution to preserve $ when reloading .cmd file
162# note: when using inline perl scripts [perl -e '...$$t=1;...']
163# in $(cmd_xxx) double $$ your perl vars
164make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
165
166# Find any prerequisites that is newer than target or that does not exist.
167# PHONY targets skipped in both cases.
168any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
169
170# Execute command if command has changed or prerequisite(s) are updated.
171#
172if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
173 @set -e; \
174 $(echo-cmd) $(cmd_$(1)); \
175 echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
176
177# Execute the command and also postprocess generated .d dependencies file.
178if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \
179 @set -e; \
180 $(echo-cmd) $(cmd_$(1)); \
181 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
182 rm -f $(depfile); \
183 mv -f $(dot-target).tmp $(dot-target).cmd)
184
185# Usage: $(call if_changed_rule,foo)
186# Will check if $(cmd_foo) or any of the prerequisites changed,
187# and if so will execute $(rule_foo).
188if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \
189 @set -e; \
190 $(rule_$(1)))
191
192###
193# why - tell why a a target got build
194# enabled by make V=2
195# Output (listed in the order they are checked):
196# (1) - due to target is PHONY
197# (2) - due to target missing
198# (3) - due to: file1.h file2.h
199# (4) - due to command line change
200# (5) - due to missing .cmd file
201# (6) - due to target not in $(targets)
202# (1) PHONY targets are always build
203# (2) No target, so we better build it
204# (3) Prerequisite is newer than target
205# (4) The command line stored in the file named dir/.target.cmd
206# differed from actual command line. This happens when compiler
207# options changes
208# (5) No dir/.target.cmd file (used to store command line)
209# (6) No dir/.target.cmd file and target not listed in $(targets)
210# This is a good hint that there is a bug in the kbuild file
211ifeq ($(KBUILD_VERBOSE),2)
212why = \
213 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \
214 $(if $(wildcard $@), \
215 $(if $(strip $(any-prereq)),- due to: $(any-prereq), \
216 $(if $(arg-check), \
217 $(if $(cmd_$@),- due to command line change, \
218 $(if $(filter $@, $(targets)), \
219 - due to missing .cmd file, \
220 - due to $(notdir $@) not in $$(targets) \
221 ) \
222 ) \
223 ) \
224 ), \
225 - due to target missing \
226 ) \
227 )
228
229echo-why = $(call escsq, $(strip $(why)))
230endif