linux/tools/build/Makefile.build
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   1# SPDX-License-Identifier: GPL-2.0
   2###
   3# Main build makefile.
   4#
   5#  Lots of this code have been borrowed or heavily inspired from parts
   6#  of kbuild code, which is not credited, but mostly developed by:
   7#
   8#  Copyright (C) Sam Ravnborg <sam@mars.ravnborg.org>, 2015
   9#  Copyright (C) Linus Torvalds <torvalds@linux-foundation.org>, 2015
  10#
  11
  12PHONY := __build
  13__build:
  14
  15ifeq ($(V),1)
  16  quiet =
  17  Q =
  18else
  19  quiet=quiet_
  20  Q=@
  21endif
  22
  23ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),)
  24  quiet=silent_
  25endif
  26
  27build-dir := $(srctree)/tools/build
  28
  29# Define $(fixdep) for dep-cmd function
  30ifeq ($(OUTPUT),)
  31  fixdep := $(build-dir)/fixdep
  32else
  33  fixdep := $(OUTPUT)/fixdep
  34endif
  35
  36# Generic definitions
  37include $(build-dir)/Build.include
  38
  39# do not force detected configuration
  40-include $(OUTPUT).config-detected
  41
  42# Init all relevant variables used in build files so
  43# 1) they have correct type
  44# 2) they do not inherit any value from the environment
  45subdir-y     :=
  46obj-y        :=
  47subdir-y     :=
  48subdir-obj-y :=
  49
  50# Build definitions
  51build-file := $(dir)/Build
  52-include $(build-file)
  53
  54quiet_cmd_flex  = FLEX    $@
  55quiet_cmd_bison = BISON   $@
  56
  57# Create directory unless it exists
  58quiet_cmd_mkdir = MKDIR   $(dir $@)
  59      cmd_mkdir = mkdir -p $(dir $@)
  60     rule_mkdir = $(if $(wildcard $(dir $@)),,@$(call echo-cmd,mkdir) $(cmd_mkdir))
  61
  62# Compile command
  63quiet_cmd_cc_o_c = CC      $@
  64      cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
  65
  66quiet_cmd_host_cc_o_c = HOSTCC  $@
  67      cmd_host_cc_o_c = $(HOSTCC) $(host_c_flags) -c -o $@ $<
  68
  69quiet_cmd_cxx_o_c = CXX     $@
  70      cmd_cxx_o_c = $(CXX) $(cxx_flags) -c -o $@ $<
  71
  72quiet_cmd_cpp_i_c = CPP     $@
  73      cmd_cpp_i_c = $(CC) $(c_flags) -E -o $@ $<
  74
  75quiet_cmd_cc_s_c = AS      $@
  76      cmd_cc_s_c = $(CC) $(c_flags) -S -o $@ $<
  77
  78quiet_cmd_gen = GEN     $@
  79
  80# Link agregate command
  81# If there's nothing to link, create empty $@ object.
  82quiet_cmd_ld_multi = LD      $@
  83      cmd_ld_multi = $(if $(strip $(obj-y)),\
  84                     $(LD) -r -o $@  $(filter $(obj-y),$^),rm -f $@; $(AR) rcs $@)
  85
  86quiet_cmd_host_ld_multi = HOSTLD  $@
  87      cmd_host_ld_multi = $(if $(strip $(obj-y)),\
  88                          $(HOSTLD) -r -o $@  $(filter $(obj-y),$^),rm -f $@; $(HOSTAR) rcs $@)
  89
  90ifneq ($(filter $(obj),$(hostprogs)),)
  91  host = host_
  92endif
  93
  94# Build rules
  95$(OUTPUT)%.o: %.c FORCE
  96        $(call rule_mkdir)
  97        $(call if_changed_dep,$(host)cc_o_c)
  98
  99$(OUTPUT)%.o: %.cpp FORCE
 100        $(call rule_mkdir)
 101        $(call if_changed_dep,cxx_o_c)
 102
 103$(OUTPUT)%.o: %.S FORCE
 104        $(call rule_mkdir)
 105        $(call if_changed_dep,$(host)cc_o_c)
 106
 107$(OUTPUT)%.i: %.c FORCE
 108        $(call rule_mkdir)
 109        $(call if_changed_dep,cpp_i_c)
 110
 111$(OUTPUT)%.s: %.S FORCE
 112        $(call rule_mkdir)
 113        $(call if_changed_dep,cpp_i_c)
 114
 115$(OUTPUT)%.s: %.c FORCE
 116        $(call rule_mkdir)
 117        $(call if_changed_dep,cc_s_c)
 118
 119# Gather build data:
 120#   obj-y        - list of build objects
 121#   subdir-y     - list of directories to nest
 122#   subdir-obj-y - list of directories objects 'dir/$(obj)-in.o'
 123obj-y        := $($(obj)-y)
 124subdir-y     := $(patsubst %/,%,$(filter %/, $(obj-y)))
 125obj-y        := $(patsubst %/, %/$(obj)-in.o, $(obj-y))
 126subdir-obj-y := $(filter %/$(obj)-in.o, $(obj-y))
 127
 128# '$(OUTPUT)/dir' prefix to all objects
 129objprefix    := $(subst ./,,$(OUTPUT)$(dir)/)
 130obj-y        := $(addprefix $(objprefix),$(obj-y))
 131subdir-obj-y := $(addprefix $(objprefix),$(subdir-obj-y))
 132
 133# Final '$(obj)-in.o' object
 134in-target := $(objprefix)$(obj)-in.o
 135
 136PHONY += $(subdir-y)
 137
 138$(subdir-y):
 139        $(Q)$(MAKE) -f $(build-dir)/Makefile.build dir=$(dir)/$@ obj=$(obj)
 140
 141$(sort $(subdir-obj-y)): $(subdir-y) ;
 142
 143$(in-target): $(obj-y) FORCE
 144        $(call rule_mkdir)
 145        $(call if_changed,$(host)ld_multi)
 146
 147__build: $(in-target)
 148        @:
 149
 150PHONY += FORCE
 151FORCE:
 152
 153# Include all cmd files to get all the dependency rules
 154# for all objects included
 155targets   := $(wildcard $(sort $(obj-y) $(in-target) $(MAKECMDGOALS)))
 156cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
 157
 158ifneq ($(cmd_files),)
 159  include $(cmd_files)
 160endif
 161
 162.PHONY: $(PHONY)
 163