xref: /linux/tools/build/Makefile.build (revision bf4afc53b77aeaa48b5409da5c8da6bb4eff7f43) 
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
79rust_common_cmd = \
80	$(RUSTC) $(rust_flags) \
81	--crate-type staticlib -L $(objtree)/rust/ \
82	--emit=dep-info=$(depfile),link
83
84quiet_cmd_rustc_a_rs = $(RUSTC) $(quiet_modtag) $@
85      cmd_rustc_a_rs = $(rust_common_cmd) -o $@ -g $< $(cmd_objtool)
86
87ifneq ($(filter $(obj),$(hostprogs)),)
88  host = host_
89endif
90
91# Build rules
92$(OUTPUT)%.o: %.c FORCE
93	$(call rule_mkdir)
94	$(call if_changed_dep,$(host)cc_o_c)
95
96$(OUTPUT)%.o: %.cpp FORCE
97	$(call rule_mkdir)
98	$(call if_changed_dep,cxx_o_c)
99
100$(OUTPUT)%.o: %.S FORCE
101	$(call rule_mkdir)
102	$(call if_changed_dep,$(host)cc_o_c)
103
104$(OUTPUT)%.i: %.c FORCE
105	$(call rule_mkdir)
106	$(call if_changed_dep,cpp_i_c)
107
108$(OUTPUT)%.s: %.S FORCE
109	$(call rule_mkdir)
110	$(call if_changed_dep,cpp_i_c)
111
112$(OUTPUT)%.s: %.c FORCE
113	$(call rule_mkdir)
114	$(call if_changed_dep,cc_s_c)
115
116# it's recommended to build a static rust library, when a foreight (to rust)
117# linker is used.
118$(OUTPUT)%.a: %.rs FORCE
119	$(call rule_mkdir)
120	$(call if_changed_dep,rustc_a_rs)
121
122# bison and flex files are generated in the OUTPUT directory
123# so it needs a separate rule to depend on them properly
124$(OUTPUT)%-bison.o: $(OUTPUT)%-bison.c FORCE
125	$(call rule_mkdir)
126	$(call if_changed_dep,$(host)cc_o_c)
127
128$(OUTPUT)%-flex.o: $(OUTPUT)%-flex.c FORCE
129	$(call rule_mkdir)
130	$(call if_changed_dep,$(host)cc_o_c)
131
132# Gather build data:
133#   obj-y        - list of build objects
134#   subdir-y     - list of directories to nest
135#   subdir-obj-y - list of directories objects 'dir/$(obj)-in.o'
136obj-y        := $($(obj)-y)
137subdir-y     := $(patsubst %/,%,$(filter %/, $(obj-y)))
138obj-y        := $(patsubst %/, %/$(obj)-in.o, $(obj-y))
139subdir-obj-y := $(filter %/$(obj)-in.o, $(obj-y))
140
141# '$(OUTPUT)/dir' prefix to all objects
142objprefix    := $(subst ./,,$(OUTPUT)$(dir)/)
143obj-y        := $(addprefix $(objprefix),$(obj-y))
144subdir-obj-y := $(addprefix $(objprefix),$(subdir-obj-y))
145
146# Separate out test log files from real build objects.
147test-y       := $(filter %_log, $(obj-y))
148obj-y        := $(filter-out %_log, $(obj-y))
149
150# Final '$(obj)-in.o' object
151in-target := $(objprefix)$(obj)-in.o
152
153PHONY += $(subdir-y)
154
155$(subdir-y):
156	$(Q)$(MAKE) -f $(build-dir)/Makefile.build dir=$(dir)/$@ obj=$(obj)
157
158$(sort $(subdir-obj-y)): $(subdir-y) ;
159
160$(in-target): $(obj-y) $(test-y) FORCE
161	$(call rule_mkdir)
162	$(call if_changed,$(host)ld_multi)
163
164__build: $(in-target)
165	@:
166
167PHONY += FORCE
168FORCE:
169
170# Include all cmd files to get all the dependency rules
171# for all objects included
172targets   := $(wildcard $(sort $(obj-y) $(in-target) $(MAKECMDGOALS)))
173cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
174
175ifneq ($(cmd_files),)
176  include $(cmd_files)
177endif
178
179.PHONY: $(PHONY)
180