1# SPDX-License-Identifier: GPL-2.0
2####
3# kbuild: Generic definitions
4
5# Convenient variables
6squote  := '
7empty   :=
8space   := $(empty) $(empty)
9space_escape := _-_SPACE_-_
10pound   := \#
11
12###
13# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
14dot-target = $(@D)/.$(@F)
15
16###
17# dependencies
18DEPS = .*.d
19DEPS_INCLUDE = $(addsuffix .d2, $(basename $(wildcard $(DEPS))))
20
21###
22# real prerequisites without phony targets
23real-prereqs = $(filter-out $(PHONY), $^)
24
25###
26# Escape single quote for use in echo statements
27escsq = $(subst $(squote),'\$(squote)',$1)
28
29# as-insn: Check whether assembler supports an instruction.
30# Usage: cflags-y += $(call as-insn,CC FLAGS,"insn",option-yes,option-no)
31as-insn = $(if $(shell echo 'void _(void) { asm volatile ( $(2) ); }' \
32                       | $(filter-out -M% %.d -include %/include/xen/config.h,$(1)) \
33                              -c -x c -o /dev/null - 2>&1),$(4),$(3))
34
35# as-option-add: Conditionally add options to flags
36# Usage: $(call as-option-add,CFLAGS,CC,"insn",option-yes,option-no)
37as-option-add = $(eval $(call as-option-add-closure,$(1),$(2),$(3),$(4),$(5)))
38define as-option-add-closure
39    ifeq ($$(call as-insn,$$($(2)) $$($(1)),$(3),y,n),y)
40        $(1) += $(4)
41    else
42        $(1) += $(5)
43    endif
44endef
45
46# cc-ifversion
47# Usage:  EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
48cc-ifversion = $(shell [ $(CONFIG_GCC_VERSION)0 $(1) $(2)000 ] && echo $(3) || echo $(4))
49
50# Shorthand for $(MAKE) clean
51# Usage:
52# $(MAKE) $(clean) dir
53clean := -f $(BASEDIR)/scripts/Makefile.clean clean -C
54
55# echo command.
56# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
57echo-cmd = $(if $($(quiet)cmd_$(1)),\
58        echo '  $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
59
60# printing commands
61cmd = @set -e; $(echo-cmd) $(cmd_$(1))
62
63###
64# if_changed      - execute command if any prerequisite is newer than
65#                   target, or command line has changed
66# if_changed_rule - as if_changed but execute rule instead
67
68ifneq ($(KBUILD_NOCMDDEP),1)
69# Check if both commands are the same including their order. Result is empty
70# string if equal. User may override this check using make KBUILD_NOCMDDEP=1
71cmd-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \
72                         $(subst $(space),$(space_escape),$(strip $(cmd_$1))))
73else
74cmd-check = $(if $(strip $(cmd_$@)),,1)
75endif
76
77# Replace >$< with >$$< to preserve $ when reloading the .cmd file
78# (needed for make)
79# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
80# (needed for make)
81# Replace >'< with >'\''< to be able to enclose the whole string in '...'
82# (needed for the shell)
83make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
84
85# Find any prerequisites that is newer than target or that does not exist.
86# PHONY targets skipped in both cases.
87any-prereq = $(filter-out $(PHONY),$?)$(filter-out $(PHONY) $(wildcard $^),$^)
88
89# Execute command if command has changed or prerequisite(s) are updated.
90if_changed = $(if $(any-prereq)$(cmd-check),                                 \
91        $(cmd);                                                              \
92        printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
93
94# Usage: $(call if_changed_rule,foo)
95# Will check if $(cmd_foo) or any of the prerequisites changed,
96# and if so will execute $(rule_foo).
97if_changed_rule = $(if $(any-prereq)$(cmd-check),$(rule_$(1)),@:)
98
99cmd_and_record =                                                             \
100        $(cmd);                                                              \
101        printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd
102
103###
104# why - tell why a target got built
105#       enabled by make V=2
106#       Output (listed in the order they are checked):
107#          (1) - due to target is PHONY
108#          (2) - due to target missing
109#          (3) - due to: file1.h file2.h
110#          (4) - due to command line change
111#          (5) - due to missing .cmd file
112#          (6) - due to target not in $(targets)
113# (1) PHONY targets are always build
114# (2) No target, so we better build it
115# (3) Prerequisite is newer than target
116# (4) The command line stored in the file named dir/.target.cmd
117#     differed from actual command line. This happens when compiler
118#     options changes
119# (5) No dir/.target.cmd file (used to store command line)
120# (6) No dir/.target.cmd file and target not listed in $(targets)
121#     This is a good hint that there is a bug in the kbuild file
122ifeq ($(KBUILD_VERBOSE),2)
123why =                                                                        \
124    $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
125        $(if $(wildcard $@),                                                 \
126            $(if $(any-prereq),- due to: $(any-prereq),                      \
127                $(if $(cmd-check),                                           \
128                    $(if $(cmd_$@),- due to command line change,             \
129                        $(if $(filter $@, $(targets)),                       \
130                            - due to missing .cmd file,                      \
131                            - due to $(notdir $@) not in $$(targets)         \
132                         )                                                   \
133                     )                                                       \
134                 )                                                           \
135             ),                                                              \
136             - due to target missing                                         \
137         )                                                                   \
138     )
139
140echo-why = $(call escsq, $(strip $(why)))
141endif
142