1 # SPDX-License-Identifier: GPL-2.0 2 #### 3 # kbuild: Generic definitions 4 5 # Convenient variables 6 comma := , 7 quote := " 8 squote := ' 9 empty := 10 space := $(empty) $(empty) 11 space_escape := _-_SPACE_-_ 12 pound := \# 13 define newline 14 15 16 endef 17 18 ### 19 # Comparison macros. 20 # Usage: $(call test-lt, $(CONFIG_LLD_VERSION), 150000) 21 # 22 # Use $(intcmp ...) if supported. (Make >= 4.4) 23 # Otherwise, fall back to the 'test' shell command. 24 ifeq ($(intcmp 1,0,,,y),y) 25 test-ge = $(intcmp $(strip $1)0, $(strip $2)0,,y,y) 26 test-gt = $(intcmp $(strip $1)0, $(strip $2)0,,,y) 27 else 28 test-ge = $(shell test $(strip $1)0 -ge $(strip $2)0 && echo y) 29 test-gt = $(shell test $(strip $1)0 -gt $(strip $2)0 && echo y) 30 endif 31 test-le = $(call test-ge, $2, $1) 32 test-lt = $(call test-gt, $2, $1) 33 34 ### 35 # Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o 36 dot-target = $(dir $@).$(notdir $@) 37 38 ### 39 # Name of target with a '.tmp_' as filename prefix. foo/bar.o => foo/.tmp_bar.o 40 tmp-target = $(dir $@).tmp_$(notdir $@) 41 42 ### 43 # The temporary file to save gcc -MMD generated dependencies must not 44 # contain a comma 45 depfile = $(subst $(comma),_,$(dot-target).d) 46 47 ### 48 # filename of target with directory and extension stripped 49 basetarget = $(basename $(notdir $@)) 50 51 ### 52 # real prerequisites without phony targets 53 real-prereqs = $(filter-out $(PHONY), $^) 54 55 ### 56 # Escape single quote for use in echo statements 57 escsq = $(subst $(squote),'\$(squote)',$1) 58 59 ### 60 # Quote a string to pass it to C files. foo => '"foo"' 61 stringify = $(squote)$(quote)$1$(quote)$(squote) 62 63 ### 64 # The path to Kbuild or Makefile. Kbuild has precedence over Makefile. 65 kbuild-file = $(or $(wildcard $(src)/Kbuild),$(src)/Makefile) 66 67 ### 68 # Read a file, replacing newlines with spaces 69 # 70 # Make 4.2 or later can read a file by using its builtin function. 71 ifneq ($(filter-out 4.0 4.1, $(MAKE_VERSION)),) 72 read-file = $(subst $(newline),$(space),$(file < $1)) 73 else 74 read-file = $(shell cat $1 2>/dev/null) 75 endif 76 77 ### 78 # Easy method for doing a status message 79 kecho := : 80 quiet_kecho := echo 81 silent_kecho := : 82 kecho := $($(quiet)kecho) 83 84 ### 85 # filechk is used to check if the content of a generated file is updated. 86 # Sample usage: 87 # 88 # filechk_sample = echo $(KERNELRELEASE) 89 # version.h: FORCE 90 # $(call filechk,sample) 91 # 92 # The rule defined shall write to stdout the content of the new file. 93 # The existing file will be compared with the new one. 94 # - If no file exist it is created 95 # - If the content differ the new file is used 96 # - If they are equal no change, and no timestamp update 97 define filechk 98 $(check-FORCE) 99 $(Q)set -e; \ 100 mkdir -p $(dir $@); \ 101 trap "rm -f $(tmp-target)" EXIT; \ 102 { $(filechk_$(1)); } > $(tmp-target); \ 103 if [ ! -r $@ ] || ! cmp -s $@ $(tmp-target); then \ 104 $(kecho) ' UPD $@'; \ 105 mv -f $(tmp-target) $@; \ 106 fi 107 endef 108 109 ### 110 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj= 111 # Usage: 112 # $(Q)$(MAKE) $(build)=dir 113 build := -f $(srctree)/scripts/Makefile.build obj 114 115 ### 116 # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.clean obj= 117 # Usage: 118 # $(Q)$(MAKE) $(clean)=dir 119 clean := -f $(srctree)/scripts/Makefile.clean obj 120 121 # pring log 122 # 123 # If quiet is "silent_", print nothing and sink stdout 124 # If quiet is "quiet_", print short log 125 # If quiet is empty, print short log and whole command 126 silent_log_print = exec >/dev/null; 127 quiet_log_print = $(if $(quiet_cmd_$1), echo ' $(call escsq,$(quiet_cmd_$1)$(why))';) 128 log_print = echo '$(pound) $(call escsq,$(or $(quiet_cmd_$1),cmd_$1 $@)$(why))'; \ 129 echo ' $(call escsq,$(cmd_$1))'; 130 131 # Delete the target on interruption 132 # 133 # GNU Make automatically deletes the target if it has already been changed by 134 # the interrupted recipe. So, you can safely stop the build by Ctrl-C (Make 135 # will delete incomplete targets), and resume it later. 136 # 137 # However, this does not work when the stderr is piped to another program, like 138 # $ make >&2 | tee log 139 # Make dies with SIGPIPE before cleaning the targets. 140 # 141 # To address it, we clean the target in signal traps. 142 # 143 # Make deletes the target when it catches SIGHUP, SIGINT, SIGQUIT, SIGTERM. 144 # So, we cover them, and also SIGPIPE just in case. 145 # 146 # Of course, this is unneeded for phony targets. 147 delete-on-interrupt = \ 148 $(if $(filter-out $(PHONY), $@), \ 149 $(foreach sig, HUP INT QUIT TERM PIPE, \ 150 trap 'rm -f $@; trap - $(sig); kill -s $(sig) $$$$' $(sig);)) 151 152 # print and execute commands 153 cmd = @$(if $(cmd_$(1)),set -e; $($(quiet)log_print) $(delete-on-interrupt) $(cmd_$(1)),:) 154 155 ### 156 # if_changed - execute command if any prerequisite is newer than 157 # target, or command line has changed 158 # if_changed_dep - as if_changed, but uses fixdep to reveal dependencies 159 # including used config symbols 160 # if_changed_rule - as if_changed but execute rule instead 161 # See Documentation/kbuild/makefiles.rst for more info 162 163 ifneq ($(KBUILD_NOCMDDEP),1) 164 # Check if both commands are the same including their order. Result is empty 165 # string if equal. User may override this check using make KBUILD_NOCMDDEP=1 166 # If the target does not exist, the *.cmd file should not be included so 167 # $(savedcmd_$@) gets empty. Then, target will be built even if $(newer-prereqs) 168 # happens to become empty. 169 cmd-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(savedcmd_$@))), \ 170 $(subst $(space),$(space_escape),$(strip $(cmd_$1)))) 171 else 172 # We still need to detect missing targets. 173 cmd-check = $(if $(strip $(savedcmd_$@)),,1) 174 endif 175 176 # Replace >$< with >$$< to preserve $ when reloading the .cmd file 177 # (needed for make) 178 # Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file 179 # (needed for make) 180 # Replace >'< with >'\''< to be able to enclose the whole string in '...' 181 # (needed for the shell) 182 make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1))))) 183 184 # Find any prerequisites that are newer than target or that do not exist. 185 # PHONY targets skipped in both cases. 186 # If there is no prerequisite other than phony targets, $(newer-prereqs) becomes 187 # empty even if the target does not exist. cmd-check saves this corner case. 188 newer-prereqs = $(filter-out $(PHONY),$?) 189 190 # It is a typical mistake to forget the FORCE prerequisite. Check it here so 191 # no more breakage will slip in. 192 check-FORCE = $(if $(filter FORCE, $^),,$(warning FORCE prerequisite is missing)) 193 194 if-changed-cond = $(newer-prereqs)$(cmd-check)$(check-FORCE) 195 196 # Execute command if command has changed or prerequisite(s) are updated. 197 if_changed = $(if $(if-changed-cond),$(cmd_and_savecmd),@:) 198 199 cmd_and_savecmd = \ 200 $(cmd); \ 201 printf '%s\n' 'savedcmd_$@ := $(make-cmd)' > $(dot-target).cmd 202 203 # Execute the command and also postprocess generated .d dependencies file. 204 if_changed_dep = $(if $(if-changed-cond),$(cmd_and_fixdep),@:) 205 206 cmd_and_fixdep = \ 207 $(cmd); \ 208 scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).cmd;\ 209 rm -f $(depfile) 210 211 # Usage: $(call if_changed_rule,foo) 212 # Will check if $(cmd_foo) or any of the prerequisites changed, 213 # and if so will execute $(rule_foo). 214 if_changed_rule = $(if $(if-changed-cond),$(rule_$(1)),@:) 215 216 ### 217 # why - tell why a target got built 218 # enabled by make V=2 219 # Output (listed in the order they are checked): 220 # (1) - due to target is PHONY 221 # (2) - due to target missing 222 # (3) - due to: file1.h file2.h 223 # (4) - due to command line change 224 # (5) - due to missing .cmd file 225 # (6) - due to target not in $(targets) 226 # (1) PHONY targets are always build 227 # (2) No target, so we better build it 228 # (3) Prerequisite is newer than target 229 # (4) The command line stored in the file named dir/.target.cmd 230 # differed from actual command line. This happens when compiler 231 # options changes 232 # (5) No dir/.target.cmd file (used to store command line) 233 # (6) No dir/.target.cmd file and target not listed in $(targets) 234 # This is a good hint that there is a bug in the kbuild file 235 ifneq ($(findstring 2, $(KBUILD_VERBOSE)),) 236 _why = \ 237 $(if $(filter $@, $(PHONY)),- due to target is PHONY, \ 238 $(if $(wildcard $@), \ 239 $(if $(newer-prereqs),- due to: $(newer-prereqs), \ 240 $(if $(cmd-check), \ 241 $(if $(savedcmd_$@),- due to command line change, \ 242 $(if $(filter $@, $(targets)), \ 243 - due to missing .cmd file, \ 244 - due to $(notdir $@) not in $$(targets) \ 245 ) \ 246 ) \ 247 ) \ 248 ), \ 249 - due to target missing \ 250 ) \ 251 ) 252 253 why = $(space)$(strip $(_why)) 254 endif 255 256 ############################################################################### 257 258 # delete partially updated (i.e. corrupted) files on error 259 .DELETE_ON_ERROR: 260 261 # do not delete intermediate files automatically 262 # 263 # .NOTINTERMEDIATE is more correct, but only available on newer Make versions. 264 # Make 4.4 introduced .NOTINTERMEDIATE, and it appears in .FEATURES, but the 265 # global .NOTINTERMEDIATE does not work. We can use it on Make > 4.4. 266 # Use .SECONDARY for older Make versions, but "newer-prereq" cannot detect 267 # deleted files. 268 ifneq ($(and $(filter notintermediate, $(.FEATURES)),$(filter-out 4.4,$(MAKE_VERSION))),) 269 .NOTINTERMEDIATE: 270 else 271 .SECONDARY: 272 endif
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