xref: /openbmc/linux/tools/build/Build.include (revision 827634ad)
1###
2# build: Generic definitions
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
11###
12# Convenient variables
13comma   := ,
14squote  := '
15
16###
17# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
18dot-target = $(dir $@).$(notdir $@)
19
20###
21# filename of target with directory and extension stripped
22basetarget = $(basename $(notdir $@))
23
24###
25# The temporary file to save gcc -MD generated dependencies must not
26# contain a comma
27depfile = $(subst $(comma),_,$(dot-target).d)
28
29###
30# Check if both arguments has same arguments. Result is empty string if equal.
31arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
32                    $(filter-out $(cmd_$@),   $(cmd_$(1))) )
33
34###
35# Escape single quote for use in echo statements
36escsq = $(subst $(squote),'\$(squote)',$1)
37
38# Echo command
39# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
40echo-cmd = $(if $($(quiet)cmd_$(1)),\
41           echo '  $(call escsq,$($(quiet)cmd_$(1)))';)
42
43###
44# Replace >$< with >$$< to preserve $ when reloading the .cmd file
45# (needed for make)
46# Replace >#< with >\#< to avoid starting a comment in the .cmd file
47# (needed for make)
48# Replace >'< with >'\''< to be able to enclose the whole string in '...'
49# (needed for the shell)
50make-cmd = $(call escsq,$(subst \#,\\\#,$(subst $$,$$$$,$(cmd_$(1)))))
51
52###
53# Find any prerequisites that is newer than target or that does not exist.
54# PHONY targets skipped in both cases.
55any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
56
57###
58# if_changed_dep  - execute command if any prerequisite is newer than
59#                   target, or command line has changed and update
60#                   dependencies in the cmd file
61if_changed_dep = $(if $(strip $(any-prereq) $(arg-check)),         \
62	@set -e;                                                   \
63	$(echo-cmd) $(cmd_$(1));                                   \
64	cat $(depfile) > $(dot-target).cmd;                        \
65	printf '%s\n' 'cmd_$@ := $(make-cmd)' >> $(dot-target).cmd)
66
67# if_changed      - execute command if any prerequisite is newer than
68#                   target, or command line has changed
69if_changed = $(if $(strip $(any-prereq) $(arg-check)),             \
70	@set -e;                                                   \
71	$(echo-cmd) $(cmd_$(1));                                   \
72	printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
73
74###
75# C flags to be used in rule definitions, includes:
76# - depfile generation
77# - global $(CFLAGS)
78# - per target C flags
79# - per object C flags
80# - BUILD_STR macro to allow '-D"$(variable)"' constructs
81c_flags = -Wp,-MD,$(depfile),-MT,$@ $(CFLAGS) -D"BUILD_STR(s)=\#s" $(CFLAGS_$(basetarget).o) $(CFLAGS_$(obj))
82