projects/linux·blob master · refs

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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
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 $(obj-y)),\
73 printf "$(objprefix)%s " $(patsubst $(objprefix)%,%,$(filter $(obj-y),$^)) | \
74 xargs $(LD) -r -o $@,rm -f $@; $(AR) rcs $@)
75
76quiet_cmd_host_ld_multi = HOSTLD $@
77 cmd_host_ld_multi = $(if $(strip $(obj-y)),\
78 printf "$(objprefix)%s " $(patsubst $(objprefix)%,%,$(filter $(obj-y),$^)) | \
79 xargs $(HOSTLD) -r -o $@,rm -f $@; $(HOSTAR) rcs $@)
80
81rust_common_cmd = \
82 $(RUSTC) $(rust_flags) \
83 --crate-type staticlib -L $(objtree)/rust/ \
84 --emit=dep-info=$(depfile),link
85
86quiet_cmd_rustc_a_rs = $(RUSTC) $(quiet_modtag) $@
87 cmd_rustc_a_rs = $(rust_common_cmd) -o $@ -g $< $(cmd_objtool)
88
89ifneq ($(filter $(obj),$(hostprogs)),)
90 host = host_
91endif
92
93# Build rules
94$(OUTPUT)%.o: %.c FORCE
95 $(call rule_mkdir)
96 $(call if_changed_dep,$(host)cc_o_c)
97
98$(OUTPUT)%.o: %.cpp FORCE
99 $(call rule_mkdir)
100 $(call if_changed_dep,cxx_o_c)
101
102$(OUTPUT)%.o: %.S FORCE
103 $(call rule_mkdir)
104 $(call if_changed_dep,$(host)cc_o_c)
105
106$(OUTPUT)%.i: %.c FORCE
107 $(call rule_mkdir)
108 $(call if_changed_dep,cpp_i_c)
109
110$(OUTPUT)%.s: %.S FORCE
111 $(call rule_mkdir)
112 $(call if_changed_dep,cpp_i_c)
113
114$(OUTPUT)%.s: %.c FORCE
115 $(call rule_mkdir)
116 $(call if_changed_dep,cc_s_c)
117
118# it's recommended to build a static rust library, when a foreight (to rust)
119# linker is used.
120$(OUTPUT)%.a: %.rs FORCE
121 $(call rule_mkdir)
122 $(call if_changed_dep,rustc_a_rs)
123
124# bison and flex files are generated in the OUTPUT directory
125# so it needs a separate rule to depend on them properly
126$(OUTPUT)%-bison.o: $(OUTPUT)%-bison.c FORCE
127 $(call rule_mkdir)
128 $(call if_changed_dep,$(host)cc_o_c)
129
130$(OUTPUT)%-flex.o: $(OUTPUT)%-flex.c FORCE
131 $(call rule_mkdir)
132 $(call if_changed_dep,$(host)cc_o_c)
133
134# Gather build data:
135# obj-y - list of build objects
136# subdir-y - list of directories to nest
137# subdir-obj-y - list of directories objects 'dir/$(obj)-in.o'
138obj-y := $($(obj)-y)
139subdir-y := $(patsubst %/,%,$(filter %/, $(obj-y)))
140obj-y := $(patsubst %/, %/$(obj)-in.o, $(obj-y))
141subdir-obj-y := $(filter %/$(obj)-in.o, $(obj-y))
142
143# '$(OUTPUT)/dir' prefix to all objects
144objprefix := $(subst ./,,$(OUTPUT)$(dir)/)
145obj-y := $(addprefix $(objprefix),$(obj-y))
146subdir-obj-y := $(addprefix $(objprefix),$(subdir-obj-y))
147
148# Separate out test log files from real build objects.
149test-y := $(filter %_log, $(obj-y))
150obj-y := $(filter-out %_log, $(obj-y))
151
152# Final '$(obj)-in.o' object
153in-target := $(objprefix)$(obj)-in.o
154
155PHONY += $(subdir-y)
156
157$(subdir-y):
158 $(Q)$(MAKE) -f $(build-dir)/Makefile.build dir=$(dir)/$@ obj=$(obj)
159
160$(sort $(subdir-obj-y)): $(subdir-y) ;
161
162$(in-target): $(obj-y) $(test-y) FORCE
163 $(call rule_mkdir)
164 $(call if_changed,$(host)ld_multi)
165
166__build: $(in-target)
167 @:
168
169PHONY += FORCE
170FORCE:
171
172# Include all cmd files to get all the dependency rules
173# for all objects included
174targets := $(wildcard $(sort $(obj-y) $(in-target) $(MAKECMDGOALS)))
175cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
176
177ifneq ($(cmd_files),)
178 include $(cmd_files)
179endif
180
181.PHONY: $(PHONY)