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. # Easy method for doing a status message
  23. kecho := :
  24. quiet_kecho := echo
  25. silent_kecho := :
  26. kecho := $($(quiet)kecho)
  27. ###
  28. # filechk is used to check if the content of a generated file is updated.
  29. # Sample usage:
  30. # define filechk_sample
  31. # echo $KERNELRELEASE
  32. # endef
  33. # version.h : Makefile
  34. # $(call filechk,sample)
  35. # The rule defined shall write to stdout the content of the new file.
  36. # The existing file will be compared with the new one.
  37. # - If no file exist it is created
  38. # - If the content differ the new file is used
  39. # - If they are equal no change, and no timestamp update
  40. # - stdin is piped in from the first prerequisite ($<) so one has
  41. # to specify a valid file as first prerequisite (often the kbuild file)
  42. define filechk
  43. $(Q)set -e; \
  44. $(kecho) ' CHK $@'; \
  45. mkdir -p $(dir $@); \
  46. $(filechk_$(1)) < $< > $@.tmp; \
  47. if [ -r $@ ] && cmp -s $@ $@.tmp; then \
  48. rm -f $@.tmp; \
  49. else \
  50. $(kecho) ' UPD $@'; \
  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) -c -xc /dev/null -o "$$TMP",$(1),$(2))
  92. # cc-option-yn
  93. # Usage: flag := $(call cc-option-yn,-march=winchip-c6)
  94. cc-option-yn = $(call try-run,\
  95. $(CC) $(KBUILD_CFLAGS) $(1) -c -xc /dev/null -o "$$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 "$$TMP",$(1),$(2))
  114. ######
  115. ###
  116. # Shorthand for $(Q)$(MAKE) -f scripts/Makefile.build obj=
  117. # Usage:
  118. # $(Q)$(MAKE) $(build)=dir
  119. build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
  120. # Prefix -I with $(srctree) if it is not an absolute path.
  121. # skip if -I has no parameter
  122. addtree = $(if $(patsubst -I%,%,$(1)), \
  123. $(if $(filter-out -I/%,$(1)),$(patsubst -I%,-I$(srctree)/%,$(1))) $(1))
  124. # Find all -I options and call addtree
  125. flags = $(foreach o,$($(1)),$(if $(filter -I%,$(o)),$(call addtree,$(o)),$(o)))
  126. # echo command.
  127. # Short version is used, if $(quiet) equals `quiet_', otherwise full one.
  128. echo-cmd = $(if $($(quiet)cmd_$(1)),\
  129. echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
  130. # printing commands
  131. cmd = @$(echo-cmd) $(cmd_$(1))
  132. # Add $(obj)/ for paths that are not absolute
  133. objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
  134. ###
  135. # if_changed - execute command if any prerequisite is newer than
  136. # target, or command line has changed
  137. # if_changed_dep - as if_changed, but uses fixdep to reveal dependencies
  138. # including used config symbols
  139. # if_changed_rule - as if_changed but execute rule instead
  140. # See Documentation/kbuild/makefiles.txt for more info
  141. ifneq ($(KBUILD_NOCMDDEP),1)
  142. # Check if both arguments has same arguments. Result is empty string if equal.
  143. # User may override this check using make KBUILD_NOCMDDEP=1
  144. arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
  145. $(filter-out $(cmd_$@), $(cmd_$(1))) )
  146. endif
  147. # >'< substitution is for echo to work,
  148. # >$< substitution to preserve $ when reloading .cmd file
  149. # note: when using inline perl scripts [perl -e '...$$t=1;...']
  150. # in $(cmd_xxx) double $$ your perl vars
  151. make-cmd = $(subst \#,\\\#,$(subst $$,$$$$,$(call escsq,$(cmd_$(1)))))
  152. # Find any prerequisites that is newer than target or that does not exist.
  153. # PHONY targets skipped in both cases.
  154. any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
  155. # Execute command if command has changed or prerequisite(s) are updated.
  156. #
  157. if_changed = $(if $(strip $(any-prereq) $(arg-check)), \
  158. @set -e; \
  159. $(echo-cmd) $(cmd_$(1)); \
  160. echo 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
  161. # Execute the command and also postprocess generated .d dependencies file.
  162. if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \
  163. @set -e; \
  164. $(echo-cmd) $(cmd_$(1)); \
  165. scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\
  166. rm -f $(depfile); \
  167. mv -f $(dot-target).tmp $(dot-target).cmd)
  168. # Usage: $(call if_changed_rule,foo)
  169. # Will check if $(cmd_foo) or any of the prerequisites changed,
  170. # and if so will execute $(rule_foo).
  171. if_changed_rule = $(if $(strip $(any-prereq) $(arg-check) ), \
  172. @set -e; \
  173. $(rule_$(1)))
  174. ###
  175. # why - tell why a a target got build
  176. # enabled by make V=2
  177. # Output (listed in the order they are checked):
  178. # (1) - due to target is PHONY
  179. # (2) - due to target missing
  180. # (3) - due to: file1.h file2.h
  181. # (4) - due to command line change
  182. # (5) - due to missing .cmd file
  183. # (6) - due to target not in $(targets)
  184. # (1) PHONY targets are always build
  185. # (2) No target, so we better build it
  186. # (3) Prerequisite is newer than target
  187. # (4) The command line stored in the file named dir/.target.cmd
  188. # differed from actual command line. This happens when compiler
  189. # options changes
  190. # (5) No dir/.target.cmd file (used to store command line)
  191. # (6) No dir/.target.cmd file and target not listed in $(targets)
  192. # This is a good hint that there is a bug in the kbuild file
  193. ifeq ($(KBUILD_VERBOSE),2)
  194. why = \
  195. $(if $(filter $@, $(PHONY)),- due to target is PHONY, \
  196. $(if $(wildcard $@), \
  197. $(if $(strip $(any-prereq)),- due to: $(any-prereq), \
  198. $(if $(arg-check), \
  199. $(if $(cmd_$@),- due to command line change, \
  200. $(if $(filter $@, $(targets)), \
  201. - due to missing .cmd file, \
  202. - due to $(notdir $@) not in $$(targets) \
  203. ) \
  204. ) \
  205. ) \
  206. ), \
  207. - due to target missing \
  208. ) \
  209. )
  210. echo-why = $(call escsq, $(strip $(why)))
  211. endif