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