Makefile.build

  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
 15build-dir := $(srctree)/tools/build
 16
 17# Define $(fixdep) for dep-cmd function
 18ifeq ($(OUTPUT),)
 19  fixdep := $(build-dir)/fixdep
 20else
 21  fixdep := $(OUTPUT)/fixdep
 22endif
 23
 24# Generic definitions
 25include $(build-dir)/Build.include
 26
 27# do not force detected configuration
 28-include $(OUTPUT).config-detected
 29
 30# Init all relevant variables used in build files so
 31# 1) they have correct type
 32# 2) they do not inherit any value from the environment
 33subdir-y     :=
 34obj-y        :=
 35subdir-y     :=
 36subdir-obj-y :=
 37
 38# Build definitions
 39build-file := $(dir)/Build
 40-include $(build-file)
 41
 42quiet_cmd_flex  = FLEX    $@
 43quiet_cmd_bison = BISON   $@
 44quiet_cmd_test  = TEST    $@
 45
 46# Create directory unless it exists
 47quiet_cmd_mkdir = MKDIR   $(dir $@)
 48      cmd_mkdir = mkdir -p $(dir $@)
 49     rule_mkdir = $(if $(wildcard $(dir $@)),,@$(call echo-cmd,mkdir) $(cmd_mkdir))
 50
 51# Compile command
 52quiet_cmd_cc_o_c = CC      $@
 53      cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
 54
 55quiet_cmd_host_cc_o_c = HOSTCC  $@
 56      cmd_host_cc_o_c = $(HOSTCC) $(host_c_flags) -c -o $@ $<
 57
 58quiet_cmd_cxx_o_c = CXX     $@
 59      cmd_cxx_o_c = $(CXX) $(cxx_flags) -c -o $@ $<
 60
 61quiet_cmd_cpp_i_c = CPP     $@
 62      cmd_cpp_i_c = $(CC) $(c_flags) -E -o $@ $<
 63
 64quiet_cmd_cc_s_c = AS      $@
 65      cmd_cc_s_c = $(CC) $(c_flags) -S -o $@ $<
 66
 67quiet_cmd_gen = GEN     $@
 68
 69# Link agregate command
 70# If there's nothing to link, create empty $@ object.
 71quiet_cmd_ld_multi = LD      $@
 72      cmd_ld_multi = $(if $(strip $(obj-y)),\
 73                     $(LD) -r -o $@  $(filter $(obj-y),$^),rm -f $@; $(AR) rcs $@)
 74
 75quiet_cmd_host_ld_multi = HOSTLD  $@
 76      cmd_host_ld_multi = $(if $(strip $(obj-y)),\
 77                          $(HOSTLD) -r -o $@  $(filter $(obj-y),$^),rm -f $@; $(HOSTAR) rcs $@)
 78
 79ifneq ($(filter $(obj),$(hostprogs)),)
 80  host = host_
 81endif
 82
 83# Build rules
 84$(OUTPUT)%.o: %.c FORCE
 85	$(call rule_mkdir)
 86	$(call if_changed_dep,$(host)cc_o_c)
 87
 88$(OUTPUT)%.o: %.cpp FORCE
 89	$(call rule_mkdir)
 90	$(call if_changed_dep,cxx_o_c)
 91
 92$(OUTPUT)%.o: %.S FORCE
 93	$(call rule_mkdir)
 94	$(call if_changed_dep,$(host)cc_o_c)
 95
 96$(OUTPUT)%.i: %.c FORCE
 97	$(call rule_mkdir)
 98	$(call if_changed_dep,cpp_i_c)
 99
100$(OUTPUT)%.s: %.S FORCE
101	$(call rule_mkdir)
102	$(call if_changed_dep,cpp_i_c)
103
104$(OUTPUT)%.s: %.c FORCE
105	$(call rule_mkdir)
106	$(call if_changed_dep,cc_s_c)
107
108# bison and flex files are generated in the OUTPUT directory
109# so it needs a separate rule to depend on them properly
110$(OUTPUT)%-bison.o: $(OUTPUT)%-bison.c FORCE
111	$(call rule_mkdir)
112	$(call if_changed_dep,$(host)cc_o_c)
113
114$(OUTPUT)%-flex.o: $(OUTPUT)%-flex.c FORCE
115	$(call rule_mkdir)
116	$(call if_changed_dep,$(host)cc_o_c)
117
118# Gather build data:
119#   obj-y        - list of build objects
120#   subdir-y     - list of directories to nest
121#   subdir-obj-y - list of directories objects 'dir/$(obj)-in.o'
122obj-y        := $($(obj)-y)
123subdir-y     := $(patsubst %/,%,$(filter %/, $(obj-y)))
124obj-y        := $(patsubst %/, %/$(obj)-in.o, $(obj-y))
125subdir-obj-y := $(filter %/$(obj)-in.o, $(obj-y))
126
127# '$(OUTPUT)/dir' prefix to all objects
128objprefix    := $(subst ./,,$(OUTPUT)$(dir)/)
129obj-y        := $(addprefix $(objprefix),$(obj-y))
130subdir-obj-y := $(addprefix $(objprefix),$(subdir-obj-y))
131
132# Separate out test log files from real build objects.
133test-y       := $(filter %_log, $(obj-y))
134obj-y        := $(filter-out %_log, $(obj-y))
135
136# Final '$(obj)-in.o' object
137in-target := $(objprefix)$(obj)-in.o
138
139PHONY += $(subdir-y)
140
141$(subdir-y):
142	$(Q)$(MAKE) -f $(build-dir)/Makefile.build dir=$(dir)/$@ obj=$(obj)
143
144$(sort $(subdir-obj-y)): $(subdir-y) ;
145
146$(in-target): $(obj-y) $(test-y) FORCE
147	$(call rule_mkdir)
148	$(call if_changed,$(host)ld_multi)
149
150__build: $(in-target)
151	@:
152
153PHONY += FORCE
154FORCE:
155
156# Include all cmd files to get all the dependency rules
157# for all objects included
158targets   := $(wildcard $(sort $(obj-y) $(in-target) $(MAKECMDGOALS)))
159cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
160
161ifneq ($(cmd_files),)
162  include $(cmd_files)
163endif
164
165.PHONY: $(PHONY)