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![Linus Torvalds](/assets/img/avatar_default.png)
One of the most remarkable improvements in this cycle is, Kbuild is now able to cache the result of shell commands. Some variables are expensive to compute, for example, $(call cc-option,...) invokes the compiler. It is not efficient to redo this computation every time, even when we are not actually building anything. Kbuild creates a hidden file ".cache.mk" that contains invoked shell commands and their results. The speed-up should be noticeable. Summary: - Fix arch build issues (hexagon, sh) - Clean up various Makefiles and scripts - Fix wrong usage of {CFLAGS,LDFLAGS}_MODULE in arch Makefiles - Cache variables that are expensive to compute - Improve cc-ldopton and ld-option for Clang - Optimize output directory creation -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAABAgAGBQJaDxaLAAoJED2LAQed4NsGIHQP/isMxxaIxIAWU56+ZcII74k7 639VgrKi9n5y25d1dBRTQg+vReHE6E2JbkCqpVOu11t7m0LT7yUK8v3WwyLf1qTN GxnqZ/WMQU5/AYVqIWo8jN4FGHpivHJ6qbeiNJM9qN4RAkzG0sZUq746VaFZYmIR Lu0Gf4m4qjifkkhXsQdWT5i7yNTidPqaL6GNb+FcFkEHlVre8jma0kJlgfHxru84 WmETpjQXvHAZ/R61vY6ekAWpqFhw3ecJY96A9npnx+SQVQdSNAdpaU0SK29jB0ON /SAfpHg9oa/gD0LFOKV6zkjnAkd4TEjrJEiHHhz5gjT/SbS3T1llBIGZ1oV4X7Y0 Vlh9KWlm1FJJI4SIzc9qUaQMp6JtLfEfHKJCc45xVaN3fNrDnR8jl80x5+95ELga dCkZgnq5u82MtTysCbHBESwDYQaVPyIrh7In+mduglaCqhqj9KoDjoLoiGfCg7SA 3tPflYVd629w5l5GrazJ40jWn1+ggMtgMOVooJNJ+dINCP+GxsUpH84Ww2Pdic+/ qLdud6TeqxrZDGzWXqKNLu8alM8NGgSr101l9gIf1oqSyy63duBpMrxGDoIJS3FU rFDoFFUhlfkAXNbQHtVGNzKtcpCjURh992j9Fa1+NfMwSce5IHkMwTvPmNSRowi8 0llLjXhD/bxK6FpdvlV8 =zIdO -----END PGP SIGNATURE----- Merge tag 'kbuild-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: "One of the most remarkable improvements in this cycle is, Kbuild is now able to cache the result of shell commands. Some variables are expensive to compute, for example, $(call cc-option,...) invokes the compiler. It is not efficient to redo this computation every time, even when we are not actually building anything. Kbuild creates a hidden file ".cache.mk" that contains invoked shell commands and their results. The speed-up should be noticeable. Summary: - Fix arch build issues (hexagon, sh) - Clean up various Makefiles and scripts - Fix wrong usage of {CFLAGS,LDFLAGS}_MODULE in arch Makefiles - Cache variables that are expensive to compute - Improve cc-ldopton and ld-option for Clang - Optimize output directory creation" * tag 'kbuild-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (30 commits) kbuild: move coccicheck help from scripts/Makefile.help to top Makefile sh: decompressor: add shipped files to .gitignore frv: .gitignore: ignore vmlinux.lds selinux: remove unnecessary assignment to subdir- kbuild: specify FORCE in Makefile.headersinst as .PHONY target kbuild: remove redundant mkdir from ./Kbuild kbuild: optimize object directory creation for incremental build kbuild: create object directories simpler and faster kbuild: filter-out PHONY targets from "targets" kbuild: remove redundant $(wildcard ...) for cmd_files calculation kbuild: create directory for make cache only when necessary sh: select KBUILD_DEFCONFIG depending on ARCH kbuild: fix linker feature test macros when cross compiling with Clang kbuild: shrink .cache.mk when it exceeds 1000 lines kbuild: do not call cc-option before KBUILD_CFLAGS initialization kbuild: Cache a few more calls to the compiler kbuild: Add a cache for generated variables kbuild: add forward declaration of default target to Makefile.asm-generic kbuild: remove KBUILD_SUBDIR_ASFLAGS and KBUILD_SUBDIR_CCFLAGS hexagon/kbuild: replace CFLAGS_MODULE with KBUILD_CFLAGS_MODULE ...
130 lines
4 KiB
Makefile
130 lines
4 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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# ==========================================================================
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# Installing headers
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#
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# All headers under include/uapi, include/generated/uapi,
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# arch/<arch>/include/uapi and arch/<arch>/include/generated/uapi are
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# exported.
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# They are preprocessed to remove __KERNEL__ section of the file.
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#
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# ==========================================================================
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PHONY := __headers
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__headers:
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include scripts/Kbuild.include
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srcdir := $(srctree)/$(obj)
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# When make is run under a fakechroot environment, the function
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# $(wildcard $(srcdir)/*/.) doesn't only return directories, but also regular
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# files. So, we are using a combination of sort/dir/wildcard which works
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# with fakechroot.
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subdirs := $(patsubst $(srcdir)/%/,%,\
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$(filter-out $(srcdir)/,\
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$(sort $(dir $(wildcard $(srcdir)/*/)))))
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# Recursion
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__headers: $(subdirs)
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PHONY += $(subdirs)
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$(subdirs):
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$(Q)$(MAKE) $(hdr-inst)=$(obj)/$@ dst=$(dst)/$@
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# Skip header install/check for include/uapi and arch/$(SRCARCH)/include/uapi.
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# We have only sub-directories there.
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skip-inst := $(if $(filter %/uapi,$(obj)),1)
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ifeq ($(skip-inst),)
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# Kbuild file is optional
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kbuild-file := $(srctree)/$(obj)/Kbuild
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-include $(kbuild-file)
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installdir := $(INSTALL_HDR_PATH)/$(dst)
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gendir := $(objtree)/$(subst include/,include/generated/,$(obj))
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header-files := $(notdir $(wildcard $(srcdir)/*.h))
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header-files += $(notdir $(wildcard $(srcdir)/*.agh))
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header-files := $(filter-out $(no-export-headers), $(header-files))
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genhdr-files := $(notdir $(wildcard $(gendir)/*.h))
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genhdr-files := $(filter-out $(header-files), $(genhdr-files))
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# files used to track state of install/check
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install-file := $(installdir)/.install
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check-file := $(installdir)/.check
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# all headers files for this dir
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all-files := $(header-files) $(genhdr-files)
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output-files := $(addprefix $(installdir)/, $(all-files))
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ifneq ($(mandatory-y),)
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missing := $(filter-out $(all-files),$(mandatory-y))
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ifneq ($(missing),)
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$(error Some mandatory headers ($(missing)) are missing in $(obj))
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endif
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endif
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# Work out what needs to be removed
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oldheaders := $(patsubst $(installdir)/%,%,$(wildcard $(installdir)/*.h))
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unwanted := $(filter-out $(all-files),$(oldheaders))
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# Prefix unwanted with full paths to $(INSTALL_HDR_PATH)
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unwanted-file := $(addprefix $(installdir)/, $(unwanted))
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printdir = $(patsubst $(INSTALL_HDR_PATH)/%/,%,$(dir $@))
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quiet_cmd_install = INSTALL $(printdir) ($(words $(all-files))\
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file$(if $(word 2, $(all-files)),s))
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cmd_install = \
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$(CONFIG_SHELL) $< $(installdir) $(srcdir) $(header-files); \
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$(CONFIG_SHELL) $< $(installdir) $(gendir) $(genhdr-files); \
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touch $@
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quiet_cmd_remove = REMOVE $(unwanted)
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cmd_remove = rm -f $(unwanted-file)
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quiet_cmd_check = CHECK $(printdir) ($(words $(all-files)) files)
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# Headers list can be pretty long, xargs helps to avoid
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# the "Argument list too long" error.
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cmd_check = for f in $(all-files); do \
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echo "$(installdir)/$${f}"; done \
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| xargs \
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$(PERL) $< $(INSTALL_HDR_PATH)/include $(SRCARCH); \
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touch $@
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ifndef HDRCHECK
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# Rules for installing headers
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__headers: $(install-file)
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@:
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targets += $(install-file)
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$(install-file): scripts/headers_install.sh \
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$(addprefix $(srcdir)/,$(header-files)) \
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$(addprefix $(gendir)/,$(genhdr-files)) FORCE
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$(if $(unwanted),$(call cmd,remove),)
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$(if $(wildcard $(dir $@)),,$(shell mkdir -p $(dir $@)))
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$(call if_changed,install)
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else
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__headers: $(check-file)
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@:
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targets += $(check-file)
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$(check-file): scripts/headers_check.pl $(output-files) FORCE
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$(call if_changed,check)
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endif
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cmd_files := $(wildcard \
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$(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd))
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ifneq ($(cmd_files),)
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include $(cmd_files)
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endif
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endif # skip-inst
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PHONY += FORCE
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FORCE: ;
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.PHONY: $(PHONY)
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