10adf3b558de5eb818205514c43194c33365f135
[sfrench/cifs-2.6.git] / scripts / Makefile.build
1 # SPDX-License-Identifier: GPL-2.0
2 # ==========================================================================
3 # Building
4 # ==========================================================================
5
6 src := $(obj)
7
8 PHONY := __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
14 obj-y :=
15 obj-m :=
16 lib-y :=
17 lib-m :=
18 always :=
19 targets :=
20 subdir-y :=
21 subdir-m :=
22 EXTRA_AFLAGS   :=
23 EXTRA_CFLAGS   :=
24 EXTRA_CPPFLAGS :=
25 EXTRA_LDFLAGS  :=
26 asflags-y  :=
27 ccflags-y  :=
28 cppflags-y :=
29 ldflags-y  :=
30
31 subdir-asflags-y :=
32 subdir-ccflags-y :=
33
34 # Read auto.conf if it exists, otherwise ignore
35 -include include/config/auto.conf
36
37 include scripts/Kbuild.include
38
39 # The filename Kbuild has precedence over Makefile
40 kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
41 kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
42 include $(kbuild-file)
43
44 include scripts/Makefile.lib
45
46 # Do not include host rules unless needed
47 ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(hostcxxlibs-m),)
48 include scripts/Makefile.host
49 endif
50
51 ifndef obj
52 $(warning kbuild: Makefile.build is included improperly)
53 endif
54
55 ifeq ($(need-modorder),)
56 ifneq ($(obj-m),)
57 $(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.)
58 $(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.)
59 endif
60 endif
61
62 # ===========================================================================
63
64 ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
65 lib-target := $(obj)/lib.a
66 real-obj-y += $(obj)/lib-ksyms.o
67 endif
68
69 ifneq ($(strip $(real-obj-y) $(need-builtin)),)
70 builtin-target := $(obj)/built-in.a
71 endif
72
73 ifeq ($(CONFIG_MODULES)$(need-modorder),y1)
74 modorder-target := $(obj)/modules.order
75 endif
76
77 mod-targets := $(patsubst %.o, %.mod, $(obj-m))
78
79 # Linus' kernel sanity checking tool
80 ifeq ($(KBUILD_CHECKSRC),1)
81   quiet_cmd_checksrc       = CHECK   $<
82         cmd_checksrc       = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
83 else ifeq ($(KBUILD_CHECKSRC),2)
84   quiet_cmd_force_checksrc = CHECK   $<
85         cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
86 endif
87
88 ifneq ($(KBUILD_ENABLE_EXTRA_GCC_CHECKS),)
89   cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $<
90 endif
91
92 # Compile C sources (.c)
93 # ---------------------------------------------------------------------------
94
95 # Default is built-in, unless we know otherwise
96 part-of-module = $(if $(filter $(basename $@).o, $(real-obj-m)),y)
97
98 modkern_cflags =                                          \
99         $(if $(part-of-module),                           \
100                 $(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
101                 $(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL))
102 quiet_modtag = $(if $(part-of-module),[M],   )
103
104 quiet_cmd_cc_s_c = CC $(quiet_modtag)  $@
105       cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS), $(c_flags)) $(DISABLE_LTO) -fverbose-asm -S -o $@ $<
106
107 $(obj)/%.s: $(src)/%.c FORCE
108         $(call if_changed_dep,cc_s_c)
109
110 quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
111 cmd_cpp_i_c       = $(CPP) $(c_flags) -o $@ $<
112
113 $(obj)/%.i: $(src)/%.c FORCE
114         $(call if_changed_dep,cpp_i_c)
115
116 # These mirror gensymtypes_S and co below, keep them in synch.
117 cmd_gensymtypes_c =                                                         \
118     $(CPP) -D__GENKSYMS__ $(c_flags) $< |                                   \
119     scripts/genksyms/genksyms $(if $(1), -T $(2))                           \
120      $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
121      $(if $(KBUILD_PRESERVE),-p)                                            \
122      -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
123
124 quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
125 cmd_cc_symtypes_c =                                                         \
126     $(call cmd_gensymtypes_c,true,$@) >/dev/null;                           \
127     test -s $@ || rm -f $@
128
129 $(obj)/%.symtypes : $(src)/%.c FORCE
130         $(call cmd,cc_symtypes_c)
131
132 # LLVM assembly
133 # Generate .ll files from .c
134 quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
135       cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $<
136
137 $(obj)/%.ll: $(src)/%.c FORCE
138         $(call if_changed_dep,cc_ll_c)
139
140 # C (.c) files
141 # The C file is compiled and updated dependency information is generated.
142 # (See cmd_cc_o_c + relevant part of rule_cc_o_c)
143
144 quiet_cmd_cc_o_c = CC $(quiet_modtag)  $@
145       cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
146
147 ifdef CONFIG_MODVERSIONS
148 # When module versioning is enabled the following steps are executed:
149 # o compile a <file>.o from <file>.c
150 # o if <file>.o doesn't contain a __ksymtab version, i.e. does
151 #   not export symbols, it's done.
152 # o otherwise, we calculate symbol versions using the good old
153 #   genksyms on the preprocessed source and postprocess them in a way
154 #   that they are usable as a linker script
155 # o generate .tmp_<file>.o from <file>.o using the linker to
156 #   replace the unresolved symbols __crc_exported_symbol with
157 #   the actual value of the checksum generated by genksyms
158 # o remove .tmp_<file>.o to <file>.o
159
160 cmd_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
170 endif
171
172 ifdef CONFIG_FTRACE_MCOUNT_RECORD
173 ifndef CC_USING_RECORD_MCOUNT
174 # compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
175 ifdef BUILD_C_RECORDMCOUNT
176 ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
177   RECORDMCOUNT_FLAGS = -w
178 endif
179 # Due to recursion, we must skip empty.o.
180 # The empty.o file is created in the make process in order to determine
181 # the target endianness and word size. It is made before all other C
182 # files, including recordmcount.
183 sub_cmd_record_mcount =                                 \
184         if [ $(@) != "scripts/mod/empty.o" ]; then      \
185                 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";   \
186         fi;
187 recordmcount_source := $(srctree)/scripts/recordmcount.c \
188                     $(srctree)/scripts/recordmcount.h
189 else
190 sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
191         "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
192         "$(if $(CONFIG_64BIT),64,32)" \
193         "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
194         "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \
195         "$(if $(part-of-module),1,0)" "$(@)";
196 recordmcount_source := $(srctree)/scripts/recordmcount.pl
197 endif # BUILD_C_RECORDMCOUNT
198 cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \
199         $(sub_cmd_record_mcount))
200 endif # CC_USING_RECORD_MCOUNT
201 endif # CONFIG_FTRACE_MCOUNT_RECORD
202
203 ifdef CONFIG_STACK_VALIDATION
204 ifneq ($(SKIP_STACK_VALIDATION),1)
205
206 __objtool_obj := $(objtree)/tools/objtool/objtool
207
208 objtool_args = $(if $(CONFIG_UNWINDER_ORC),orc generate,check)
209
210 objtool_args += $(if $(part-of-module), --module,)
211
212 ifndef CONFIG_FRAME_POINTER
213 objtool_args += --no-fp
214 endif
215 ifdef CONFIG_GCOV_KERNEL
216 objtool_args += --no-unreachable
217 endif
218 ifdef CONFIG_RETPOLINE
219   objtool_args += --retpoline
220 endif
221 ifdef CONFIG_X86_SMAP
222   objtool_args += --uaccess
223 endif
224
225 # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
226 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
227 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
228 cmd_objtool = $(if $(patsubst y%,, \
229         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
230         $(__objtool_obj) $(objtool_args) $@)
231 objtool_obj = $(if $(patsubst y%,, \
232         $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
233         $(__objtool_obj))
234
235 endif # SKIP_STACK_VALIDATION
236 endif # CONFIG_STACK_VALIDATION
237
238 # Rebuild all objects when objtool changes, or is enabled/disabled.
239 objtool_dep = $(objtool_obj)                                    \
240               $(wildcard include/config/orc/unwinder.h          \
241                          include/config/stack/validation.h)
242
243 ifdef CONFIG_TRIM_UNUSED_KSYMS
244 cmd_gen_ksymdeps = \
245         $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd
246 endif
247
248 define rule_cc_o_c
249         $(call cmd,checksrc)
250         $(call cmd_and_fixdep,cc_o_c)
251         $(call cmd,gen_ksymdeps)
252         $(call cmd,checkdoc)
253         $(call cmd,objtool)
254         $(call cmd,modversions_c)
255         $(call cmd,record_mcount)
256 endef
257
258 define rule_as_o_S
259         $(call cmd_and_fixdep,as_o_S)
260         $(call cmd,gen_ksymdeps)
261         $(call cmd,objtool)
262         $(call cmd,modversions_S)
263 endef
264
265 # List module undefined symbols (or empty line if not enabled)
266 ifdef CONFIG_TRIM_UNUSED_KSYMS
267 cmd_undef_syms = $(NM) $< | sed -n 's/^  *U //p' | xargs echo
268 else
269 cmd_undef_syms = echo
270 endif
271
272 # Built-in and composite module parts
273 $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE
274         $(call cmd,force_checksrc)
275         $(call if_changed_rule,cc_o_c)
276
277 cmd_mod = { \
278         echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \
279         $(cmd_undef_syms); \
280         } > $@
281
282 $(obj)/%.mod: $(obj)/%.o FORCE
283         $(call if_changed,mod)
284
285 targets += $(mod-targets)
286
287 quiet_cmd_cc_lst_c = MKLST   $@
288       cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
289                      $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
290                                      System.map $(OBJDUMP) > $@
291
292 $(obj)/%.lst: $(src)/%.c FORCE
293         $(call if_changed_dep,cc_lst_c)
294
295 # header test (header-test-y, header-test-m target)
296 # ---------------------------------------------------------------------------
297
298 quiet_cmd_cc_s_h = CC      $@
299       cmd_cc_s_h = $(CC) $(c_flags) -S -o $@ -x c /dev/null -include $<
300
301 $(obj)/%.h.s: $(src)/%.h FORCE
302         $(call if_changed_dep,cc_s_h)
303
304 # Compile assembler sources (.S)
305 # ---------------------------------------------------------------------------
306
307 modkern_aflags = $(if $(part-of-module),                                \
308                         $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE),       \
309                         $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL))
310
311 # .S file exports must have their C prototypes defined in asm/asm-prototypes.h
312 # or a file that it includes, in order to get versioned symbols. We build a
313 # dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
314 # the .S file (with trailing ';'), and run genksyms on that, to extract vers.
315 #
316 # This is convoluted. The .S file must first be preprocessed to run guards and
317 # expand names, then the resulting exports must be constructed into plain
318 # EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
319 # to make the genksyms input.
320 #
321 # These mirror gensymtypes_c and co above, keep them in synch.
322 cmd_gensymtypes_S =                                                         \
323    { echo "\#include <linux/kernel.h>" ;                                    \
324      echo "\#include <asm/asm-prototypes.h>" ;                              \
325     $(CPP) $(a_flags) $< |                                                  \
326      grep "\<___EXPORT_SYMBOL\>" |                                          \
327      sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \
328     $(CPP) -D__GENKSYMS__ $(c_flags) -xc - |                                \
329     scripts/genksyms/genksyms $(if $(1), -T $(2))                           \
330      $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
331      $(if $(KBUILD_PRESERVE),-p)                                            \
332      -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
333
334 quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
335 cmd_cc_symtypes_S =                                                         \
336     $(call cmd_gensymtypes_S,true,$@) >/dev/null;                           \
337     test -s $@ || rm -f $@
338
339 $(obj)/%.symtypes : $(src)/%.S FORCE
340         $(call cmd,cc_symtypes_S)
341
342
343 quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
344 cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $<
345
346 $(obj)/%.s: $(src)/%.S FORCE
347         $(call if_changed_dep,cpp_s_S)
348
349 quiet_cmd_as_o_S = AS $(quiet_modtag)  $@
350       cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
351
352 ifdef CONFIG_MODVERSIONS
353
354 ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
355
356 ifneq ($(ASM_PROTOTYPES),)
357
358 # versioning matches the C process described above, with difference that
359 # we parse asm-prototypes.h C header to get function definitions.
360
361 cmd_modversions_S =                                                             \
362         if $(OBJDUMP) -h $@ | grep -q __ksymtab; then                           \
363                 $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))  \
364                     > $(@D)/.tmp_$(@F:.o=.ver);                                 \
365                                                                                 \
366                 $(LD) $(KBUILD_LDFLAGS) -r -o $(@D)/.tmp_$(@F) $@               \
367                         -T $(@D)/.tmp_$(@F:.o=.ver);                            \
368                 mv -f $(@D)/.tmp_$(@F) $@;                                      \
369                 rm -f $(@D)/.tmp_$(@F:.o=.ver);                                 \
370         fi
371 endif
372 endif
373
374 $(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
375         $(call if_changed_rule,as_o_S)
376
377 targets += $(filter-out $(subdir-obj-y), $(real-obj-y)) $(real-obj-m) $(lib-y)
378 targets += $(extra-y) $(MAKECMDGOALS) $(always)
379
380 # Linker scripts preprocessor (.lds.S -> .lds)
381 # ---------------------------------------------------------------------------
382 quiet_cmd_cpp_lds_S = LDS     $@
383       cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
384                              -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
385
386 $(obj)/%.lds: $(src)/%.lds.S FORCE
387         $(call if_changed_dep,cpp_lds_S)
388
389 # ASN.1 grammar
390 # ---------------------------------------------------------------------------
391 quiet_cmd_asn1_compiler = ASN.1   $(basename $@).[ch]
392       cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
393                                 $(basename $@).c $(basename $@).h
394
395 $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
396         $(call cmd,asn1_compiler)
397
398 # Build the compiled-in targets
399 # ---------------------------------------------------------------------------
400
401 # To build objects in subdirs, we need to descend into the directories
402 $(sort $(subdir-obj-y)): $(subdir-ym) ;
403
404 #
405 # Rule to compile a set of .o files into one .a file (without symbol table)
406 #
407 ifdef builtin-target
408
409 quiet_cmd_ar_builtin = AR      $@
410       cmd_ar_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(real-prereqs)
411
412 $(builtin-target): $(real-obj-y) FORCE
413         $(call if_changed,ar_builtin)
414
415 targets += $(builtin-target)
416 endif # builtin-target
417
418 #
419 # Rule to create modules.order file
420 #
421 # Create commands to either record .ko file or cat modules.order from
422 # a subdirectory
423 $(modorder-target): $(subdir-ym) FORCE
424         $(Q){ $(foreach m, $(modorder), \
425         $(if $(filter %/modules.order, $m), cat $m, echo $m);) :; } \
426         | $(AWK) '!x[$$0]++' - > $@
427
428 #
429 # Rule to compile a set of .o files into one .a file (with symbol table)
430 #
431 ifdef lib-target
432
433 $(lib-target): $(lib-y) FORCE
434         $(call if_changed,ar)
435
436 targets += $(lib-target)
437
438 dummy-object = $(obj)/.lib_exports.o
439 ksyms-lds = $(dot-target).lds
440
441 quiet_cmd_export_list = EXPORTS $@
442 cmd_export_list = $(OBJDUMP) -h $< | \
443         sed -ne '/___ksymtab/s/.*+\([^ ]*\).*/EXTERN(\1)/p' >$(ksyms-lds);\
444         rm -f $(dummy-object);\
445         echo | $(CC) $(a_flags) -c -o $(dummy-object) -x assembler -;\
446         $(LD) $(ld_flags) -r -o $@ -T $(ksyms-lds) $(dummy-object);\
447         rm $(dummy-object) $(ksyms-lds)
448
449 $(obj)/lib-ksyms.o: $(lib-target) FORCE
450         $(call if_changed,export_list)
451
452 targets += $(obj)/lib-ksyms.o
453
454 endif
455
456 # NOTE:
457 # Do not replace $(filter %.o,^) with $(real-prereqs). When a single object
458 # module is turned into a multi object module, $^ will contain header file
459 # dependencies recorded in the .*.cmd file.
460 quiet_cmd_link_multi-m = LD [M]  $@
461       cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^)
462
463 $(multi-used-m): FORCE
464         $(call if_changed,link_multi-m)
465 $(call multi_depend, $(multi-used-m), .o, -objs -y -m)
466
467 targets += $(multi-used-m)
468 targets := $(filter-out $(PHONY), $(targets))
469
470 # Add intermediate targets:
471 # When building objects with specific suffix patterns, add intermediate
472 # targets that the final targets are derived from.
473 intermediate_targets = $(foreach sfx, $(2), \
474                                 $(patsubst %$(strip $(1)),%$(sfx), \
475                                         $(filter %$(strip $(1)), $(targets))))
476 # %.asn1.o <- %.asn1.[ch] <- %.asn1
477 # %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
478 # %.lex.o <- %.lex.c <- %.l
479 # %.tab.o <- %.tab.[ch] <- %.y
480 targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
481            $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
482            $(call intermediate_targets, .lex.o, .lex.c) \
483            $(call intermediate_targets, .tab.o, .tab.c .tab.h)
484
485 # Build
486 # ---------------------------------------------------------------------------
487
488 ifdef single-build
489
490 curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \
491                         $(if $(filter $(x) $(basename $(x)).o, $(targets)), $(x))))
492
493 # Handle single targets without any rule: show "Nothing to be done for ..." or
494 # "No rule to make target ..." depending on whether the target exists.
495 unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \
496                         $(filter $(obj)/%, \
497                                 $(filter-out $(curdir-single), \
498                                         $(KBUILD_SINGLE_TARGETS))))
499
500 __build: $(curdir-single) $(subdir-ym)
501 ifneq ($(unknown-single),)
502         $(Q)$(MAKE) -f /dev/null $(unknown-single)
503 endif
504         @:
505
506 ifeq ($(curdir-single),)
507 # Nothing to do in this directory. Do not include any .*.cmd file for speed-up
508 targets :=
509 else
510 targets += $(curdir-single)
511 endif
512
513 else
514
515 __build: $(if $(KBUILD_BUILTIN),$(builtin-target) $(lib-target) $(extra-y)) \
516          $(if $(KBUILD_MODULES),$(obj-m) $(mod-targets) $(modorder-target)) \
517          $(subdir-ym) $(always)
518         @:
519
520 endif
521
522 # Descending
523 # ---------------------------------------------------------------------------
524
525 PHONY += $(subdir-ym)
526 $(subdir-ym):
527         $(Q)$(MAKE) $(build)=$@ \
528         $(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \
529         need-builtin=$(if $(filter $@/built-in.a, $(subdir-obj-y)),1) \
530         need-modorder=$(if $(need-modorder),$(if $(filter $@/modules.order, $(modorder)),1))
531
532 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
533 # ---------------------------------------------------------------------------
534
535 PHONY += FORCE
536
537 FORCE:
538
539 # Read all saved command lines and dependencies for the $(targets) we
540 # may be building above, using $(if_changed{,_dep}). As an
541 # optimization, we don't need to read them if the target does not
542 # exist, we will rebuild anyway in that case.
543
544 existing-targets := $(wildcard $(sort $(targets)))
545
546 -include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
547
548 ifdef building_out_of_srctree
549 # Create directories for object files if they do not exist
550 obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets))))
551 # If targets exist, their directories apparently exist. Skip mkdir.
552 existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets))))
553 obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs)))
554 ifneq ($(obj-dirs),)
555 $(shell mkdir -p $(obj-dirs))
556 endif
557 endif
558
559 .PHONY: $(PHONY)