mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-09-04 20:19:47 +08:00
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
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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 $(wildcard ...) for cmd_files calculation
kbuild: create directory for make cache only when necessary
sh: select KBUILD_DEFCONFIG depending on ARCH
kbuild: fix linker feature test macros when cross compiling with Clang
kbuild: shrink .cache.mk when it exceeds 1000 lines
kbuild: do not call cc-option before KBUILD_CFLAGS initialization
kbuild: Cache a few more calls to the compiler
kbuild: Add a cache for generated variables
kbuild: add forward declaration of default target to Makefile.asm-generic
kbuild: remove KBUILD_SUBDIR_ASFLAGS and KBUILD_SUBDIR_CCFLAGS
hexagon/kbuild: replace CFLAGS_MODULE with KBUILD_CFLAGS_MODULE
...
43 lines
1.2 KiB
Makefile
43 lines
1.2 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0
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# include/asm-generic contains a lot of files that are used
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# verbatim by several architectures.
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#
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# This Makefile reads the file arch/$(SRCARCH)/include/$(src)/Kbuild
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# and for each file listed in this file with generic-y creates
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# a small wrapper file in $(obj) (arch/$(SRCARCH)/include/generated/$(src))
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PHONY := all
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all:
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kbuild-file := $(srctree)/arch/$(SRCARCH)/include/$(src)/Kbuild
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-include $(kbuild-file)
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include scripts/Kbuild.include
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# Create output directory if not already present
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_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
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# Stale wrappers when the corresponding files are removed from generic-y
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# need removing.
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generated-y := $(generic-y) $(generated-y)
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all-files := $(patsubst %, $(obj)/%, $(generated-y))
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old-headers := $(wildcard $(obj)/*.h)
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unwanted := $(filter-out $(all-files),$(old-headers))
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quiet_cmd_wrap = WRAP $@
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cmd_wrap = echo "\#include <asm-generic/$*.h>" >$@
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quiet_cmd_remove = REMOVE $(unwanted)
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cmd_remove = rm -f $(unwanted)
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all: $(patsubst %, $(obj)/%, $(generic-y)) FORCE
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$(if $(unwanted),$(call cmd,remove),)
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@:
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$(obj)/%.h:
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$(call cmd,wrap)
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PHONY += FORCE
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.PHONY: $(PHONY)
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FORCE: ;
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