Kbuild.include 8.3 KB

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  1. ####
  2. # kbuild: Generic definitions
  3. # Convenient variables
  4. comma := ,
  5. squote := '
  6. empty :=
  7. space := $(empty) $(empty)
  8. ###
  9. # Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
  10. dot-target = $(dir $@).$(notdir $@)
  11. ###
  12. # The temporary file to save gcc -MD generated dependencies must not
  13. # contain a comma
  14. depfile = $(subst $(comma),_,$(dot-target).d)
  15. ###
  16. # filename of target with directory and extension stripped
  17. basetarget = $(basename $(notdir $@))
  18. ###
  19. # Escape single quote for use in echo statements
  20. escsq = $(subst $(squote),'\$(squote)',$1)
  21. ###
  22. # filechk is used to check if the content of a generated file is updated.
  23. # Sample usage:
  24. # define filechk_sample
  25. # echo $KERNELRELEASE
  26. # endef
  27. # version.h : Makefile
  28. # $(call filechk,sample)
  29. # The rule defined shall write to stdout the content of the new file.
  30. # The existing file will be compared with the new one.
  31. # - If no file exist it is created
  32. # - If the content differ the new file is used
  33. # - If they are equal no change, and no timestamp update
  34. # - stdin is piped in from the first prerequisite ($<) so one has
  35. # to specify a valid file as first prerequisite (often the kbuild file)
  36. define filechk
  37. $(Q)set -e; \
  38. echo ' CHK $@'; \
  39. mkdir -p $(dir $@); \
  40. $(filechk_$(1)) < $< > $@.tmp; \
  41. if [ -r $@ ] && cmp -s $@ $@.tmp; then \
  42. rm -f $@.tmp; \
  43. else \
  44. echo ' UPD $@'; \
  45. mv -f $@.tmp $@; \
  46. fi
  47. endef
  48. ######
  49. # gcc support functions
  50. # See documentation in Documentation/kbuild/makefiles.txt
  51. # output directory for tests below
  52. TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
  53. # try-run
  54. # Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
  55. # Exit code chooses option. "$$TMP" is can be used as temporary file and
  56. # is automatically cleaned up.
  57. try-run = $(shell set -e; \
  58. TMP="$(TMPOUT).$$$$.tmp"; \
  59. if ($(1)) >/dev/null 2>&1; \
  60. then echo "$(2)"; \
  61. else echo "$(3)"; \
  62. fi; \
  63. rm -f "$$TMP")
  64. # as-option
  65. # Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
  66. as-option = $(call try-run,\
  67. $(CC) $(CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2))
  68. # as-instr
  69. # Usage: cflags-y += $(call as-instr,instr,option1,option2)
  70. as-instr = $(call try-run,\
  71. echo -e "$(1)" | $(CC) $(AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
  72. # cc-option
  73. # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
  74. cc-option = $(call try-run,\
  75. $(CC) $(CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",$(1),$(2))
  76. # cc-option-yn
  77. # Usage: flag := $(call cc-option-yn,-march=winchip-c6)
  78. cc-option-yn = $(call try-run,\
  79. $(CC) $(CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",y,n)
  80. # cc-option-align
  81. # Prefix align with either -falign or -malign
  82. cc-option-align = $(subst -functions=0,,\
  83. $(call cc-option,-falign-functions=0,-malign-functions=0))
  84. # cc-version
  85. # Usage gcc-ver := $(call cc-version,$(CC))
  86. cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
  87. # cc-ifversion
  88. # Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
  89. cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
  90. # ld-option
  91. # Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
  92. ld-option = $(call try-run,\
  93. $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
  94. ######
  95. ###
  96. # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
  97. # Usage:
  98. # $(Q)$(MAKE) $(build)=dir
  99. build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
  100. # Prefix -I with $(srctree) if it is not an absolute path.
  101. addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
  102. # Find all -I options and call addtree
  103. flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
  104. # echo command.
  105. # Short version is used, if $(quiet) equals `quiet_', otherwise full one.
  106. echo-cmd = $(if $($(quiet)cmd_$(1)),\
  107. echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
  108. # printing commands
  109. cmd = @$(echo-cmd) $(cmd_$(1))
  110. # Add $(obj)/ for paths that are not absolute
  111. objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
  112. ###
  113. # if_changed - execute command if any prerequisite is newer than
  114. # target, or command line has changed
  115. # if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
  116. # including used config symbols
  117. # if_changed_rule - as if_changed but execute rule instead
  118. # See Documentation/kbuild/makefiles.txt for more info
  119. ifneq ($(KBUILD_NOCMDDEP),1)
  120. # Check if both arguments has same arguments. Result is empty string if equal.
  121. # User may override this check using make KBUILD_NOCMDDEP=1
  122. arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
  123. $(filter-out $(cmd_$@), $(cmd_$(1))) )
  124. endif
  125. # >'< substitution is for echo to work,
  126. # >$< substitution to preserve $ when reloading .cmd file
  127. # note: when using inline perl scripts [perl -e '...$$t=1;...']
  128. # in $(cmd_xxx) double $$ your perl vars
  129. make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
  130. # Find any prerequisites that is newer than target or that does not exist.
  131. # PHONY targets skipped in both cases.
  132. any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
  133. # Execute command if command has changed or prerequisite(s) are updated.
  134. #
  135. if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
  136. @set -e; \
  137. $(echo-cmd) $(cmd_$(1)); \
  138. echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
  139. # Execute the command and also postprocess generated .d dependencies file.
  140. if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \
  141. @set -e; \
  142. $(echo-cmd) $(cmd_$(1)); \
  143. scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
  144. rm -f $(depfile); \
  145. mv -f $(dot-target).tmp $(dot-target).cmd)
  146. # Usage: $(call if_changed_rule,foo)
  147. # Will check if $(cmd_foo) or any of the prerequisites changed,
  148. # and if so will execute $(rule_foo).
  149. if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \
  150. @set -e; \
  151. $(rule_$(1)))
  152. ###
  153. # why - tell why a a target got build
  154. # enabled by make V=2
  155. # Output (listed in the order they are checked):
  156. # (1) - due to target is PHONY
  157. # (2) - due to target missing
  158. # (3) - due to: file1.h file2.h
  159. # (4) - due to command line change
  160. # (5) - due to missing .cmd file
  161. # (6) - due to target not in $(targets)
  162. # (1) PHONY targets are always build
  163. # (2) No target, so we better build it
  164. # (3) Prerequisite is newer than target
  165. # (4) The command line stored in the file named dir/.target.cmd
  166. # differed from actual command line. This happens when compiler
  167. # options changes
  168. # (5) No dir/.target.cmd file (used to store command line)
  169. # (6) No dir/.target.cmd file and target not listed in $(targets)
  170. # This is a good hint that there is a bug in the kbuild file
  171. ifeq ($(KBUILD_VERBOSE),2)
  172. why = \
  173. $(if $(filter $@, $(PHONY)),- due to target is PHONY, \
  174. $(if $(wildcard $@), \
  175. $(if $(strip $(any-prereq)),- due to: $(any-prereq), \
  176. $(if $(arg-check), \
  177. $(if $(cmd_$@),- due to command line change, \
  178. $(if $(filter $@, $(targets)), \
  179. - due to missing .cmd file, \
  180. - due to $(notdir $@) not in $$(targets) \
  181. ) \
  182. ) \
  183. ) \
  184. ), \
  185. - due to target missing \
  186. ) \
  187. )
  188. echo-why = $(call escsq, $(strip $(why)))
  189. endif