Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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)