blob: cdc21270625e26b08c1171d021a89ff12422288f [file] [log] [blame]
b.liue9582032025-04-17 19:18:16 +08001# SPDX-License-Identifier: GPL-2.0
2# ==========================================================================
3# Building
4# ==========================================================================
5
6src := $(obj)
7
8PHONY := __build
9__build:
10
11# Init all relevant variables used in kbuild files so
12# 1) they have correct type
13# 2) they do not inherit any value from the environment
14obj-y :=
15obj-m :=
16lib-y :=
17lib-m :=
18always :=
19targets :=
20subdir-y :=
21subdir-m :=
22EXTRA_AFLAGS :=
23EXTRA_CFLAGS :=
24EXTRA_CPPFLAGS :=
25EXTRA_LDFLAGS :=
26asflags-y :=
27ccflags-y :=
28cppflags-y :=
29ldflags-y :=
30
31subdir-asflags-y :=
32subdir-ccflags-y :=
33
34# Read auto.conf if it exists, otherwise ignore
35-include include/config/auto.conf
36
37include scripts/Kbuild.include
38
39# The filename Kbuild has precedence over Makefile
40kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
41kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
42include $(kbuild-file)
43
44include scripts/Makefile.lib
45
46# Do not include host rules unless needed
47ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
48include scripts/Makefile.host
49endif
50
51ifndef obj
52$(warning kbuild: Makefile.build is included improperly)
53endif
54
55ifeq ($(need-modorder),)
56ifneq ($(obj-m),)
57$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.)
58$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.)
59endif
60endif
61
62# ===========================================================================
63
64ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
65lib-target := $(obj)/lib.a
66real-obj-y += $(obj)/lib-ksyms.o
67endif
68
69ifneq ($(strip $(real-obj-y) $(need-builtin)),)
70builtin-target := $(obj)/built-in.a
71endif
72
73ifeq ($(CONFIG_MODULES)$(need-modorder),y1)
74modorder-target := $(obj)/modules.order
75endif
76
77mod-targets := $(patsubst %.o, %.mod, $(obj-m))
78
79# Linus' kernel sanity checking tool
80ifeq ($(KBUILD_CHECKSRC),1)
81 quiet_cmd_checksrc = CHECK $<
82 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
83else ifeq ($(KBUILD_CHECKSRC),2)
84 quiet_cmd_force_checksrc = CHECK $<
85 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
86endif
87
88ifneq ($(KBUILD_EXTRA_WARN),)
89 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $<
90endif
91
92# Compile C sources (.c)
93# ---------------------------------------------------------------------------
94
95quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
96 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
97
98$(obj)/%.s: $(src)/%.c FORCE
99 $(call if_changed_dep,cc_s_c)
100
101quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
102cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $<
103
104$(obj)/%.i: $(src)/%.c FORCE
105 $(call if_changed_dep,cpp_i_c)
106
107# These mirror gensymtypes_S and co below, keep them in synch.
108cmd_gensymtypes_c = \
109 $(CPP) -D__GENKSYMS__ $(c_flags) $< | \
110 scripts/genksyms/genksyms $(if $(1), -T $(2)) \
111 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
112 $(if $(KBUILD_PRESERVE),-p) \
113 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
114
115quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
116cmd_cc_symtypes_c = \
117 $(call cmd_gensymtypes_c,true,$@) >/dev/null; \
118 test -s $@ || rm -f $@
119
120$(obj)/%.symtypes : $(src)/%.c FORCE
121 $(call cmd,cc_symtypes_c)
122
123# LLVM assembly
124# Generate .ll files from .c
125quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@
126 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
127
128$(obj)/%.ll: $(src)/%.c FORCE
129 $(call if_changed_dep,cc_ll_c)
130
131# C (.c) files
132# The C file is compiled and updated dependency information is generated.
133# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
134
135quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
136 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
137
138ifdef CONFIG_MODVERSIONS
139# When module versioning is enabled the following steps are executed:
140# o compile a <file>.o from <file>.c
141# o if <file>.o doesn't contain a __ksymtab version, i.e. does
142# not export symbols, it's done.
143# o otherwise, we calculate symbol versions using the good old
144# genksyms on the preprocessed source and postprocess them in a way
145# that they are usable as a linker script
146# o generate .tmp_<file>.o from <file>.o using the linker to
147# replace the unresolved symbols __crc_exported_symbol with
148# the actual value of the checksum generated by genksyms
149# o remove .tmp_<file>.o to <file>.o
150
151ifdef CONFIG_LTO_CLANG
152# Generate .o.symversions files for each .o with exported symbols, and link these
153# to the kernel and/or modules at the end.
154cmd_modversions_c = \
155 if $(NM) $@ | grep -q __ksymtab; then \
156 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
157 > $@.symversions; \
158 fi;
159else
160cmd_modversions_c = \
161 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
162 $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
163 > $(@D)/.tmp_$(@F:.o=.ver); \
164 \
165 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
166 -T $(@D)/.tmp_$(@F:.o=.ver); \
167 mv -f $(@D)/.tmp_$(@F) $@; \
168 rm -f $(@D)/.tmp_$(@F:.o=.ver); \
169 fi
170endif
171endif
172
173ifdef CONFIG_FTRACE_MCOUNT_RECORD
174ifndef CC_USING_RECORD_MCOUNT
175# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
176ifdef BUILD_C_RECORDMCOUNT
177ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
178 RECORDMCOUNT_FLAGS = -w
179endif
180
181ifdef CONFIG_LTO_CLANG
182# With LTO, we postpone running recordmcount until after the LTO link step, so
183# let's export the parameters for the link script.
184export RECORDMCOUNT_FLAGS
185else
186# Due to recursion, we must skip empty.o.
187# The empty.o file is created in the make process in order to determine
188# the target endianness and word size. It is made before all other C
189# files, including recordmcount.
190sub_cmd_record_mcount = \
191 if [ $(@) != "scripts/mod/empty.o" ]; then \
192 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
193 fi;
194endif
195
196recordmcount_source := $(srctree)/scripts/recordmcount.c \
197 $(srctree)/scripts/recordmcount.h
198else
199sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
200 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
201 "$(if $(CONFIG_64BIT),64,32)" \
202 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
203 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \
204 "$(if $(part-of-module),1,0)" "$(@)";
205
206recordmcount_source := $(srctree)/scripts/recordmcount.pl
207endif # BUILD_C_RECORDMCOUNT
208ifndef CONFIG_LTO_CLANG
209cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \
210 $(sub_cmd_record_mcount))
211endif # CONFIG_LTO_CLANG
212endif # CC_USING_RECORD_MCOUNT
213endif # CONFIG_FTRACE_MCOUNT_RECORD
214
215ifdef CONFIG_STACK_VALIDATION
216ifneq ($(SKIP_STACK_VALIDATION),1)
217
218__objtool_obj := $(objtree)/tools/objtool/objtool
219
220objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
221
222objtool_args += $(if $(part-of-module), --module,)
223
224ifndef CONFIG_FRAME_POINTER
225objtool_args += --no-fp
226endif
227ifdef CONFIG_GCOV_KERNEL
228objtool_args += --no-unreachable
229endif
230ifdef CONFIG_RETPOLINE
231 objtool_args += --retpoline
232endif
233ifdef CONFIG_X86_SMAP
234 objtool_args += --uaccess
235endif
236
237# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
238# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
239# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
240cmd_objtool = $(if $(patsubst y%,, \
241 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
242 $(__objtool_obj) $(objtool_args) $@)
243objtool_obj = $(if $(patsubst y%,, \
244 $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
245 $(__objtool_obj))
246
247endif # SKIP_STACK_VALIDATION
248endif # CONFIG_STACK_VALIDATION
249
250# Rebuild all objects when objtool changes, or is enabled/disabled.
251objtool_dep = $(objtool_obj) \
252 $(wildcard include/config/orc/unwinder.h \
253 include/config/stack/validation.h)
254
255ifdef CONFIG_TRIM_UNUSED_KSYMS
256cmd_gen_ksymdeps = \
257 $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd
258
259# List module undefined symbols
260undefined_syms = $(NM) $< | $(AWK) '$$1 == "U" { printf("%s%s", x++ ? " " : "", $$2) }';
261endif
262
263define rule_cc_o_c
264 $(call cmd_and_fixdep,cc_o_c)
265 $(call cmd,gen_ksymdeps)
266 $(call cmd,checksrc)
267 $(call cmd,checkdoc)
268 $(call cmd,objtool)
269 $(call cmd,modversions_c)
270 $(call cmd,record_mcount)
271endef
272
273define rule_as_o_S
274 $(call cmd_and_fixdep,as_o_S)
275 $(call cmd,gen_ksymdeps)
276 $(call cmd,objtool)
277 $(call cmd,modversions_S)
278endef
279
280# Built-in and composite module parts
281.SECONDEXPANSION:
282$(obj)/%.o: $(src)/%.c $(recordmcount_source) $$(objtool_dep) FORCE
283 $(call if_changed_rule,cc_o_c)
284 $(call cmd,force_checksrc)
285
286cmd_mod = { \
287 echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \
288 $(undefined_syms) echo; \
289 } > $@
290
291$(obj)/%.mod: $(obj)/%.o FORCE
292 $(call if_changed,mod)
293
294targets += $(mod-targets)
295
296quiet_cmd_cc_lst_c = MKLST $@
297 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
298 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
299 System.map $(OBJDUMP) > $@
300
301$(obj)/%.lst: $(src)/%.c FORCE
302 $(call if_changed_dep,cc_lst_c)
303
304# Compile assembler sources (.S)
305# ---------------------------------------------------------------------------
306
307# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
308# or a file that it includes, in order to get versioned symbols. We build a
309# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
310# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
311#
312# This is convoluted. The .S file must first be preprocessed to run guards and
313# expand names, then the resulting exports must be constructed into plain
314# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
315# to make the genksyms input.
316#
317# These mirror gensymtypes_c and co above, keep them in synch.
318cmd_gensymtypes_S = \
319 { echo "\#include <linux/kernel.h>" ; \
320 echo "\#include <asm/asm-prototypes.h>" ; \
321 $(CPP) $(a_flags) $< | \
322 grep "\<___EXPORT_SYMBOL\>" | \
323 sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \
324 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \
325 scripts/genksyms/genksyms $(if $(1), -T $(2)) \
326 $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS)) \
327 $(if $(KBUILD_PRESERVE),-p) \
328 -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
329
330quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
331cmd_cc_symtypes_S = \
332 $(call cmd_gensymtypes_S,true,$@) >/dev/null; \
333 test -s $@ || rm -f $@
334
335$(obj)/%.symtypes : $(src)/%.S FORCE
336 $(call cmd,cc_symtypes_S)
337
338
339quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
340cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
341
342$(obj)/%.s: $(src)/%.S FORCE
343 $(call if_changed_dep,cpp_s_S)
344
345quiet_cmd_as_o_S = AS $(quiet_modtag) $@
346 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
347
348ifdef CONFIG_ASM_MODVERSIONS
349
350# versioning matches the C process described above, with difference that
351# we parse asm-prototypes.h C header to get function definitions.
352
353cmd_modversions_S = \
354 if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \
355 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
356 > $(@D)/.tmp_$(@F:.o=.ver); \
357 \
358 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@ \
359 -T $(@D)/.tmp_$(@F:.o=.ver); \
360 mv -f $(@D)/.tmp_$(@F) $@; \
361 rm -f $(@D)/.tmp_$(@F:.o=.ver); \
362 fi
363endif
364
365$(obj)/%.o: $(src)/%.S $$(objtool_dep) FORCE
366 $(call if_changed_rule,as_o_S)
367
368targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y)
369targets += $(extra-y) $(MAKECMDGOALS) $(always)
370
371# Linker scripts preprocessor (.lds.S -> .lds)
372# ---------------------------------------------------------------------------
373quiet_cmd_cpp_lds_S = LDS $@
374 cmd_cpp_lds_S = $(CPP) $(EXTRA_LDSFLAGS) $(cpp_flags) -P -U$(ARCH) \
375 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
376
377$(obj)/%.lds: $(src)/%.lds.S FORCE
378 $(call if_changed_dep,cpp_lds_S)
379
380# ASN.1 grammar
381# ---------------------------------------------------------------------------
382quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch]
383 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
384 $(basename $@).c $(basename $@).h
385
386$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
387 $(call cmd,asn1_compiler)
388
389# Build the compiled-in targets
390# ---------------------------------------------------------------------------
391
392# To build objects in subdirs, we need to descend into the directories
393$(sort $(subdir-obj-y)): $(subdir-ym) ;
394
395# combine symversions for later processing
396quiet_cmd_update_lto_symversions = SYMVER $@
397ifeq ($(CONFIG_LTO_CLANG) $(CONFIG_MODVERSIONS),y y)
398 cmd_update_lto_symversions = \
399 rm -f $@.symversions \
400 $(foreach n, $(filter-out FORCE,$^), \
401 $(if $(wildcard $(n).symversions), \
402 ; cat $(n).symversions >> $@.symversions))
403else
404 cmd_update_lto_symversions = echo >/dev/null
405endif
406
407#
408# Rule to compile a set of .o files into one .a file (without symbol table)
409#
410ifdef builtin-target
411
412quiet_cmd_ar_builtin = AR $@
413 cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs)
414
415quiet_cmd_ar_and_symver = AR $@
416 cmd_ar_and_symver = $(cmd_update_lto_symversions); $(cmd_ar_builtin)
417
418$(builtin-target): $(real-obj-y) FORCE
419 $(call if_changed,ar_and_symver)
420
421targets += $(builtin-target)
422endif # builtin-target
423
424#
425# Rule to create modules.order file
426#
427# Create commands to either record .ko file or cat modules.order from
428# a subdirectory
429$(modorder-target): $(subdir-ym) FORCE
430 $(Q){ $(foreach m, $(modorder), \
431 $(if $(filter %/modules.order, $m), cat $m, echo $m);) :; } \
432 | $(AWK) '!x[$$0]++' - > $@
433
434#
435# Rule to compile a set of .o files into one .a file (with symbol table)
436#
437ifdef lib-target
438
439quiet_cmd_ar_lib = AR $@
440 cmd_ar_lib = $(cmd_update_lto_symversions); $(cmd_ar)
441
442$(lib-target): $(lib-y) FORCE
443 $(call if_changed,ar_lib)
444
445targets += $(lib-target)
446
447dummy-object = $(obj)/.lib_exports.o
448ksyms-lds = $(dot-target).lds
449
450ifdef CONFIG_LTO_CLANG
451# Objdump doesn't understand LLVM IR. Use llvm-nm to dump symbols.
452dump_export_list = $(NM)
453else
454dump_export_list = $(OBJDUMP) -h
455endif
456
457quiet_cmd_export_list = EXPORTS $@
458cmd_export_list = $(dump_export_list) $< | \
459 sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\
460 rm -f $(dummy-object);\
461 echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
462 $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
463 rm $(dummy-object) $(ksyms-lds)
464
465$(obj)/lib-ksyms.o: $(lib-target) FORCE
466 $(call if_changed,export_list)
467
468targets += $(obj)/lib-ksyms.o
469
470endif
471
472# NOTE:
473# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object
474# module is turned into a multi object module, $^ will contain header file
475# dependencies recorded in the .*.cmd file.
476ifdef CONFIG_LTO_CLANG
477quiet_cmd_link_multi-m = AR [M] $@
478cmd_link_multi-m = \
479 $(cmd_update_lto_symversions); \
480 rm -f $@; \
481 $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(filter %.o,$^)
482else
483quiet_cmd_link_multi-m = LD [M] $@
484 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^)
485endif
486
487$(multi-used-m): FORCE
488 $(call if_changed,link_multi-m)
489$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
490
491targets += $(multi-used-m)
492targets := $(filter-out $(PHONY), $(targets))
493
494# Add intermediate targets:
495# When building objects with specific suffix patterns, add intermediate
496# targets that the final targets are derived from.
497intermediate_targets = $(foreach sfx, $(2), \
498 $(patsubst %$(strip $(1)),%$(sfx), \
499 $(filter %$(strip $(1)), $(targets))))
500# %.asn1.o <- %.asn1.[ch] <- %.asn1
501# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
502# %.lex.o <- %.lex.c <- %.l
503# %.tab.o <- %.tab.[ch] <- %.y
504targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
505 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
506 $(call intermediate_targets, .lex.o, .lex.c) \
507 $(call intermediate_targets, .tab.o, .tab.c .tab.h)
508
509# Build
510# ---------------------------------------------------------------------------
511
512ifdef single-build
513
514curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \
515 $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x))))
516
517# Handle single targets without any rule: show "Nothing to be done for ..." or
518# "No rule to make target ..." depending on whether the target exists.
519unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \
520 $(filter $(obj)/%, \
521 $(filter-out $(curdir-single), \
522 $(KBUILD_SINGLE_TARGETS))))
523
524__build: $(curdir-single) $(subdir-ym)
525ifneq ($(unknown-single),)
526 $(Q)$(MAKE) -f /dev/null $(unknown-single)
527endif
528 @:
529
530ifeq ($(curdir-single),)
531# Nothing to do in this directory. Do not include any .*.cmd file for speed-up
532targets :=
533else
534targets += $(curdir-single)
535endif
536
537else
538
539__build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
540 $(if $(KBUILD_MODULES),$(obj-m) $(mod-targets) $(modorder-target)) \
541 $(subdir-ym) $(always)
542 @:
543
544endif
545
546# Descending
547# ---------------------------------------------------------------------------
548
549PHONY += $(subdir-ym)
550$(subdir-ym):
551 $(Q)$(MAKE) $(build)=$@ \
552 $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \
553 need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1) \
554 need-modorder=$(if $(need-modorder),$(if $(filter $@/modules.order, $(modorder)),1))
555
556# Add FORCE to the prequisites of a target to force it to be always rebuilt.
557# ---------------------------------------------------------------------------
558
559PHONY += FORCE
560
561FORCE:
562
563# Read all saved command lines and dependencies for the $(targets) we
564# may be building above, using $(if_changed{,_dep}). As an
565# optimization, we don't need to read them if the target does not
566# exist, we will rebuild anyway in that case.
567
568existing-targets := $(wildcard $(sort $(targets)))
569
570-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
571
572# Create directories for object files if they do not exist
573obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets))))
574# If targets exist, their directories apparently exist. Skip mkdir.
575existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets))))
576obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs)))
577ifneq ($(obj-dirs),)
578$(shell mkdir -p $(obj-dirs))
579endif
580
581.PHONY: $(PHONY)