diff options
Diffstat (limited to 'scripts/Kbuild.include')
| -rw-r--r-- | scripts/Kbuild.include | 90 |
1 files changed, 76 insertions, 14 deletions
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 9ffd3dda3889..dfadb1c94368 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -8,6 +8,8 @@ squote := ' empty := space := $(empty) $(empty) space_escape := _-_SPACE_-_ +right_paren := ) +left_paren := ( ### # Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o @@ -80,6 +82,60 @@ cc-cross-prefix = \ echo $(c); \ fi))) +# Tools for caching Makefile variables that are "expensive" to compute. +# +# Here we want to help deal with variables that take a long time to compute +# by making it easy to store these variables in a cache. +# +# The canonical example here is testing for compiler flags. On a simple system +# each call to the compiler takes 10 ms, but on a system with a compiler that's +# called through various wrappers it can take upwards of 100 ms. If we have +# 100 calls to the compiler this can take 1 second (on a simple system) or 10 +# seconds (on a complicated system). +# +# The "cache" will be in Makefile syntax and can be directly included. +# Any time we try to reference a variable that's not in the cache we'll +# calculate it and store it in the cache for next time. + +# Include values from last time +make-cache := $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/,$(if $(obj),$(obj)/)).cache.mk +ifeq ($(wildcard $(dir $(make-cache))),) +$(shell mkdir -p '$(dir $(make-cache))') +endif +$(make-cache): ; +-include $(make-cache) + +# Usage: $(call __sanitize-opt,Hello=Hola$(comma)Goodbye Adios) +# +# Convert all '$', ')', '(', '\', '=', ' ', ',', ':' to '_' +__sanitize-opt = $(subst $$,_,$(subst $(right_paren),_,$(subst $(left_paren),_,$(subst \,_,$(subst =,_,$(subst $(space),_,$(subst $(comma),_,$(subst :,_,$(1))))))))) + +# Usage: $(call shell-cached,shell_command) +# Example: $(call shell-cached,md5sum /usr/bin/gcc) +# +# If we've already seen a call to this exact shell command (even in a +# previous invocation of make!) we'll return the value. If not, we'll +# compute it and store the result for future runs. +# +# This is a bit of voodoo, but basic explanation is that if the variable +# was undefined then we'll evaluate the shell command and store the result +# into the variable. We'll then store that value in the cache and finally +# output the value. +# +# NOTE: The $$(2) here isn't actually a parameter to __run-and-store. We +# happen to know that the caller will have their shell command in $(2) so the +# result of "call"ing this will produce a reference to that $(2). The reason +# for this strangeness is to avoid an extra level of eval (and escaping) of +# $(2). +define __run-and-store +ifeq ($(origin $(1)),undefined) + $$(eval $(1) := $$(shell $$(2))) + $$(shell echo '$(1) := $$($(1))' >> $(make-cache)) +endif +endef +__shell-cached = $(eval $(call __run-and-store,$(1)))$($(1)) +shell-cached = $(call __shell-cached,__cached_$(call __sanitize-opt,$(1)),$(1)) + # output directory for tests below TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/) @@ -87,30 +143,36 @@ TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/) # Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise) # Exit code chooses option. "$$TMP" serves as a temporary file and is # automatically cleaned up. -try-run = $(shell set -e; \ +__try-run = set -e; \ TMP="$(TMPOUT).$$$$.tmp"; \ TMPO="$(TMPOUT).$$$$.o"; \ if ($(1)) >/dev/null 2>&1; \ then echo "$(2)"; \ else echo "$(3)"; \ fi; \ - rm -f "$$TMP" "$$TMPO") + rm -f "$$TMP" "$$TMPO" + +try-run = $(shell $(__try-run)) + +# try-run-cached +# This works like try-run, but the result is cached. +try-run-cached = $(call shell-cached,$(__try-run)) # as-option # Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,) -as-option = $(call try-run,\ +as-option = $(call try-run-cached,\ $(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2)) # as-instr # Usage: cflags-y += $(call as-instr,instr,option1,option2) -as-instr = $(call try-run,\ +as-instr = $(call try-run-cached,\ printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3)) # __cc-option # Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586) -__cc-option = $(call try-run,\ +__cc-option = $(call try-run-cached,\ $(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4)) # Do not attempt to build with gcc plugins during cc-option tests. @@ -130,23 +192,23 @@ hostcc-option = $(call __cc-option, $(HOSTCC),\ # cc-option-yn # Usage: flag := $(call cc-option-yn,-march=winchip-c6) -cc-option-yn = $(call try-run,\ +cc-option-yn = $(call try-run-cached,\ $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n) # cc-disable-warning # Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable) -cc-disable-warning = $(call try-run,\ +cc-disable-warning = $(call try-run-cached,\ $(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) # cc-name # Expands to either gcc or clang -cc-name = $(shell $(CC) -v 2>&1 | grep -q "clang version" && echo clang || echo gcc) +cc-name = $(call shell-cached,$(CC) -v 2>&1 | grep -q "clang version" && echo clang || echo gcc) # cc-version -cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC)) +cc-version = $(call shell-cached,$(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh $(CC)) # cc-fullversion -cc-fullversion = $(shell $(CONFIG_SHELL) \ +cc-fullversion = $(call shell-cached,$(CONFIG_SHELL) \ $(srctree)/scripts/gcc-version.sh -p $(CC)) # cc-ifversion @@ -159,22 +221,22 @@ cc-if-fullversion = $(shell [ $(cc-fullversion) $(1) $(2) ] && echo $(3) || echo # cc-ldoption # Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both) -cc-ldoption = $(call try-run,\ +cc-ldoption = $(call try-run-cached,\ $(CC) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2)) # ld-option # Usage: LDFLAGS += $(call ld-option, -X) -ld-option = $(call try-run,\ +ld-option = $(call try-run-cached,\ $(CC) -x c /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2)) # ar-option # Usage: KBUILD_ARFLAGS := $(call ar-option,D) # Important: no spaces around options -ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2)) +ar-option = $(call try-run-cached, $(AR) rc$(1) "$$TMP",$(1),$(2)) # ld-version # Note this is mainly for HJ Lu's 3 number binutil versions -ld-version = $(shell $(LD) --version | $(srctree)/scripts/ld-version.sh) +ld-version = $(call shell-cached,$(LD) --version | $(srctree)/scripts/ld-version.sh) # ld-ifversion # Usage: $(call ld-ifversion, -ge, 22252, y) |