xref: /openbmc/linux/tools/build/Makefile.build (revision c819e2cf) 
1###
2# Main build makefile.
3#
4#  Lots of this code have been borrowed or heavily inspired from parts
5#  of kbuild code, which is not credited, but mostly developed by:
6#
7#  Copyright (C) Sam Ravnborg <sam@mars.ravnborg.org>, 2015
8#  Copyright (C) Linus Torvalds <torvalds@linux-foundation.org>, 2015
9#
10
11PHONY := __build
12__build:
13
14ifeq ($(V),1)
15  quiet =
16else
17  quiet=quiet_
18endif
19
20build-dir := $(srctree)/tools/build
21
22# Generic definitions
23include $(build-dir)/Build.include
24
25# Init all relevant variables used in build files so
26# 1) they have correct type
27# 2) they do not inherit any value from the environment
28subdir-y     :=
29obj-y        :=
30subdir-y     :=
31subdir-obj-y :=
32
33# Build definitions
34build-file := $(dir)/Build
35include $(build-file)
36
37# Compile command
38quiet_cmd_cc_o_c = CC       $@
39      cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
40
41# Link agregate command
42# If there's nothing to link, create empty $@ object.
43quiet_cmd_ld_multi = LD       $@
44      cmd_ld_multi = $(if $(strip $(obj-y)),\
45		       $(LD) -r -o $@ $(obj-y),rm -f $@; $(AR) rcs $@)
46
47# Build rules
48$(OUTPUT)%.o: %.c FORCE
49	$(call if_changed_dep,cc_o_c)
50
51$(OUTPUT)%.o: %.S FORCE
52	$(call if_changed_dep,cc_o_c)
53
54# Gather build data:
55#   obj-y        - list of build objects
56#   subdir-y     - list of directories to nest
57#   subdir-obj-y - list of directories objects 'dir/$(obj)-in.o'
58obj-y        := $($(obj)-y)
59subdir-y     := $(patsubst %/,%,$(filter %/, $(obj-y)))
60obj-y        := $(patsubst %/, %/$(obj)-in.o, $(obj-y))
61subdir-obj-y := $(filter %/$(obj)-in.o, $(obj-y))
62
63# '$(OUTPUT)/dir' prefix to all objects
64prefix       := $(subst ./,,$(OUTPUT)$(dir)/)
65obj-y        := $(addprefix $(prefix),$(obj-y))
66subdir-obj-y := $(addprefix $(prefix),$(subdir-obj-y))
67
68# Final '$(obj)-in.o' object
69in-target := $(prefix)$(obj)-in.o
70
71PHONY += $(subdir-y)
72
73$(subdir-y):
74	@$(MAKE) -f $(build-dir)/Makefile.build dir=$(dir)/$@ obj=$(obj)
75
76$(sort $(subdir-obj-y)): $(subdir-y) ;
77
78$(in-target): $(obj-y) FORCE
79	$(call rule_mkdir)
80	$(call if_changed,ld_multi)
81
82__build: $(in-target)
83	@:
84
85PHONY += FORCE
86FORCE:
87
88# Include all cmd files to get all the dependency rules
89# for all objects included
90targets   := $(wildcard $(sort $(obj-y) $(in-target)))
91cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
92
93ifneq ($(cmd_files),)
94  include $(cmd_files)
95endif
96
97.PHONY: $(PHONY)
98