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