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