Kbuild.include 9.1 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. chk_filechk = :
  37. quiet_chk_filechk = echo ' CHK $@'
  38. silent_chk_filechk = :
  39. upd_filechk = :
  40. quiet_upd_filechk = echo ' UPD $@'
  41. silent_upd_filechk = :
  42. define filechk
  43. $(Q)set -e; \
  44. $($(quiet)chk_filechk); \
  45. mkdir -p $(dir $@); \
  46. $(filechk_$(1)) < $< > $@.tmp; \
  47. if [ -r $@ ] && cmp -s $@ $@.tmp; then \
  48. rm -f $@.tmp; \
  49. else \
  50. $($(quiet)upd_filechk); \
  51. mv -f $@.tmp $@; \
  52. fi
  53. endef
  54. ######
  55. # gcc support functions
  56. # See documentation in Documentation/kbuild/makefiles.txt
  57. # cc-cross-prefix
  58. # Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
  59. # Return first prefix where a prefix$(CC) is found in PATH.
  60. # If no $(CC) found in PATH with listed prefixes return nothing
  61. cc-cross-prefix = \
  62. $(word 1, $(foreach c,$(1), \
  63. $(shell set -e; \
  64. if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \
  65. echo $(c); \
  66. fi)))
  67. # output directory for tests below
  68. TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
  69. # try-run
  70. # Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
  71. # Exit code chooses option. "$$TMP" is can be used as temporary file and
  72. # is automatically cleaned up.
  73. try-run = $(shell set -e; \
  74. TMP="$(TMPOUT).$$$$.tmp"; \
  75. if ($(1)) >/dev/null 2>&1; \
  76. then echo "$(2)"; \
  77. else echo "$(3)"; \
  78. fi; \
  79. rm -f "$$TMP")
  80. # as-option
  81. # Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
  82. as-option = $(call try-run,\
  83. $(CC) $(KBUILD_CFLAGS) $(1) -c -xassembler /dev/null -o "$$TMP",$(1),$(2))
  84. # as-instr
  85. # Usage: cflags-y += $(call as-instr,instr,option1,option2)
  86. as-instr = $(call try-run,\
  87. echo -e "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" -,$(2),$(3))
  88. # cc-option
  89. # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
  90. cc-option = $(call try-run,\
  91. $(CC) $(KBUILD_CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",$(1),$(2))
  92. # cc-option-yn
  93. # Usage: flag := $(call cc-option-yn,-march=winchip-c6)
  94. cc-option-yn = $(call try-run,\
  95. $(CC) $(KBUILD_CFLAGS) $(1) -S -xc /dev/null -o "$$TMP",y,n)
  96. # cc-option-align
  97. # Prefix align with either -falign or -malign
  98. cc-option-align = $(subst -functions=0,,\
  99. $(call cc-option,-falign-functions=0,-malign-functions=0))
  100. # cc-version
  101. # Usage gcc-ver := $(call cc-version)
  102. cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC))
  103. # cc-fullversion
  104. # Usage gcc-ver := $(call cc-fullversion)
  105. cc-fullversion = $(shell $(CONFIG_SHELL) \
  106. $(srctree)/scripts/gcc-version.sh -p $(CC))
  107. # cc-ifversion
  108. # Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
  109. cc-ifversion = $(shell [ $(call cc-version, $(CC)) $(1) $(2) ] && echo $(3))
  110. # ld-option
  111. # Usage: ldflags += $(call ld-option, -Wl$(comma)--hash-style=both)
  112. ld-option = $(call try-run,\
  113. $(CC) $(1) -nostdlib -xc /dev/null -o "$$TMP",$(1),$(2))
  114. ######
  115. ###
  116. # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
  117. # Usage:
  118. # $(Q)$(MAKE) $(build)=dir
  119. build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
  120. # Prefix -I with $(srctree) if it is not an absolute path.
  121. addtree = $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1)
  122. # Find all -I options and call addtree
  123. flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
  124. # echo command.
  125. # Short version is used, if $(quiet) equals `quiet_', otherwise full one.
  126. echo-cmd = $(if $($(quiet)cmd_$(1)),\
  127. echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
  128. # printing commands
  129. cmd = @$(echo-cmd) $(cmd_$(1))
  130. # Add $(obj)/ for paths that are not absolute
  131. objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
  132. ###
  133. # if_changed - execute command if any prerequisite is newer than
  134. # target, or command line has changed
  135. # if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
  136. # including used config symbols
  137. # if_changed_rule - as if_changed but execute rule instead
  138. # See Documentation/kbuild/makefiles.txt for more info
  139. ifneq ($(KBUILD_NOCMDDEP),1)
  140. # Check if both arguments has same arguments. Result is empty string if equal.
  141. # User may override this check using make KBUILD_NOCMDDEP=1
  142. arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
  143. $(filter-out $(cmd_$@), $(cmd_$(1))) )
  144. endif
  145. # >'< substitution is for echo to work,
  146. # >$< substitution to preserve $ when reloading .cmd file
  147. # note: when using inline perl scripts [perl -e '...$$t=1;...']
  148. # in $(cmd_xxx) double $$ your perl vars
  149. make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
  150. # Find any prerequisites that is newer than target or that does not exist.
  151. # PHONY targets skipped in both cases.
  152. any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
  153. # Execute command if command has changed or prerequisite(s) are updated.
  154. #
  155. if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
  156. @set -e; \
  157. $(echo-cmd) $(cmd_$(1)); \
  158. echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
  159. # Execute the command and also postprocess generated .d dependencies file.
  160. if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \
  161. @set -e; \
  162. $(echo-cmd) $(cmd_$(1)); \
  163. scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
  164. rm -f $(depfile); \
  165. mv -f $(dot-target).tmp $(dot-target).cmd)
  166. # Usage: $(call if_changed_rule,foo)
  167. # Will check if $(cmd_foo) or any of the prerequisites changed,
  168. # and if so will execute $(rule_foo).
  169. if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \
  170. @set -e; \
  171. $(rule_$(1)))
  172. ###
  173. # why - tell why a a target got build
  174. # enabled by make V=2
  175. # Output (listed in the order they are checked):
  176. # (1) - due to target is PHONY
  177. # (2) - due to target missing
  178. # (3) - due to: file1.h file2.h
  179. # (4) - due to command line change
  180. # (5) - due to missing .cmd file
  181. # (6) - due to target not in $(targets)
  182. # (1) PHONY targets are always build
  183. # (2) No target, so we better build it
  184. # (3) Prerequisite is newer than target
  185. # (4) The command line stored in the file named dir/.target.cmd
  186. # differed from actual command line. This happens when compiler
  187. # options changes
  188. # (5) No dir/.target.cmd file (used to store command line)
  189. # (6) No dir/.target.cmd file and target not listed in $(targets)
  190. # This is a good hint that there is a bug in the kbuild file
  191. ifeq ($(KBUILD_VERBOSE),2)
  192. why = \
  193. $(if $(filter $@, $(PHONY)),- due to target is PHONY, \
  194. $(if $(wildcard $@), \
  195. $(if $(strip $(any-prereq)),- due to: $(any-prereq), \
  196. $(if $(arg-check), \
  197. $(if $(cmd_$@),- due to command line change, \
  198. $(if $(filter $@, $(targets)), \
  199. - due to missing .cmd file, \
  200. - due to $(notdir $@) not in $$(targets) \
  201. ) \
  202. ) \
  203. ) \
  204. ), \
  205. - due to target missing \
  206. ) \
  207. )
  208. echo-why = $(call escsq, $(strip $(why)))
  209. endif