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)
42 quiet_chk_filechk = echo ' CHK $@'
43silent_chk_filechk = :
44 quiet_upd_filechk = echo ' UPD $@'
45silent_upd_filechk = :
46define filechk
47 $(Q)set -e; \
48 $($(quiet)chk_filechk); \
49 mkdir -p $(dir $@); \
50 $(filechk_$(1)) < $< > $@.tmp; \
51 if [ -r $@ ] && cmp -s $@ $@.tmp; then \
52 rm -f $@.tmp; \
53 else \
54 $($(quiet)upd_filechk); \
55 mv -f $@.tmp $@; \
56 fi
57endef
58
59######
60# gcc support functions
61# See documentation in Documentation/kbuild/makefiles.txt
62
63# cc-cross-prefix
64# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
65# Return first prefix where a prefix$(CC) is found in PATH.
66# If no $(CC) found in PATH with listed prefixes return nothing
67cc-cross-prefix = \
68 $(word 1, $(foreach c,$(1), \
69 $(shell set -e; \
70 if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \
71 echo $(c); \
72 fi)))
73
74# output directory for tests below
75TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
76
77# try-run
78# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
79# Exit code chooses option. "$$TMP" is can be used as temporary file and
80# is automatically cleaned up.
81try-run = $(shell set -e; \
82 TMP="$(TMPOUT).$$$$.tmp"; \
83 if ($(1)) >/dev/null 2>&1; \
84 then echo "$(2)"; \
85 else echo "$(3)"; \
86 fi; \
87 rm -f "$$TMP")
88
89# as-option
90# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
91
92as-option = $(call try-run,\
93 $(CC) $(KBUILD_CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2))
94
95# as-instr
96# Usage: cflags-y += $(call as-instr,instr,option1,option2)
97
98as-instr = $(call try-run,\
99 echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
100
101# cc-option
102# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
103
104cc-option = $(call try-run,\
105 $(CC) $(KBUILD_CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",$(1),$(2))
106
107# cc-option-yn
108# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
109cc-option-yn = $(call try-run,\
110 $(CC) $(KBUILD_CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",y,n)
111
112# cc-option-align
113# Prefix align with either -falign or -malign
114cc-option-align = $(subst -functions=0,,\
115 $(call cc-option,-falign-functions=0,-malign-functions=0))
116
117# cc-version
118# Usage gcc-ver := $(call cc-version)
119cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
120
121# cc-fullversion
122# Usage gcc-ver := $(call cc-fullversion)
123cc-fullversion = $(shell $(CONFIG_SHELL) \
124 $(srctree)/scripts/gcc-version.sh -p $(CC))
125
126# cc-ifversion
127# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
128cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
129
130# ld-option
131# Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
132ld-option = $(call try-run,\
133 $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
134
135######
136
137###
138# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
139# Usage:
140# $(Q)$(MAKE) $(build)=dir
141build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
142
143# Prefix -I with $(srctree) if it is not an absolute path.
144addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
145
146# Find all -I options and call addtree
147flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
148
149# echo command.
150# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
151echo-cmd = $(if $($(quiet)cmd_$(1)),\
152 echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
153
154# printing commands
155cmd = @$(echo-cmd) $(cmd_$(1))
156
157# Add $(obj)/ for paths that are not absolute
158objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
159
160###
161# if_changed - execute command if any prerequisite is newer than
162# target, or command line has changed
163# if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
164# including used config symbols
165# if_changed_rule - as if_changed but execute rule instead
166# See Documentation/kbuild/makefiles.txt for more info
167
168ifneq ($(KBUILD_NOCMDDEP),1)
169# Check if both arguments has same arguments. Result is empty string if equal.
170# User may override this check using make KBUILD_NOCMDDEP=1
171arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
172 $(filter-out $(cmd_$@), $(cmd_$(1))) )
173endif
174
175# >'< substitution is for echo to work,
176# >$< substitution to preserve $ when reloading .cmd file
177# note: when using inline perl scripts [perl -e '...$$t=1;...']
178# in $(cmd_xxx) double $$ your perl vars
179make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
180
181# Find any prerequisites that is newer than target or that does not exist.
182# PHONY targets skipped in both cases.
183any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
184
185# Execute command if command has changed or prerequisite(s) are updated.
186#
187if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
188 @set -e; \
189 $(echo-cmd) $(cmd_$(1)); \
190 echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
191
192# Execute the command and also postprocess generated .d dependencies file.
193if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \
194 @set -e; \
195 $(echo-cmd) $(cmd_$(1)); \
196 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
197 rm -f $(depfile); \
198 mv -f $(dot-target).tmp $(dot-target).cmd)
199
200# Usage: $(call if_changed_rule,foo)
201# Will check if $(cmd_foo) or any of the prerequisites changed,
202# and if so will execute $(rule_foo).
203if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \
204 @set -e; \
205 $(rule_$(1)))
206
207###
208# why - tell why a a target got build
209# enabled by make V=2
210# Output (listed in the order they are checked):
211# (1) - due to target is PHONY
212# (2) - due to target missing
213# (3) - due to: file1.h file2.h
214# (4) - due to command line change
215# (5) - due to missing .cmd file
216# (6) - due to target not in $(targets)
217# (1) PHONY targets are always build
218# (2) No target, so we better build it
219# (3) Prerequisite is newer than target
220# (4) The command line stored in the file named dir/.target.cmd
221# differed from actual command line. This happens when compiler
222# options changes
223# (5) No dir/.target.cmd file (used to store command line)
224# (6) No dir/.target.cmd file and target not listed in $(targets)
225# This is a good hint that there is a bug in the kbuild file
226ifeq ($(KBUILD_VERBOSE),2)
227why = \
228 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \
229 $(if $(wildcard $@), \
230 $(if $(strip $(any-prereq)),- due to: $(any-prereq), \
231 $(if $(arg-check), \
232 $(if $(cmd_$@),- due to command line change, \
233 $(if $(filter $@, $(targets)), \
234 - due to missing .cmd file, \
235 - due to $(notdir $@) not in $$(targets) \
236 ) \
237 ) \
238 ) \
239 ), \
240 - due to target missing \
241 ) \
242 )
243
244echo-why = $(call escsq, $(strip $(why)))
245endif