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authorLinus Torvalds <torvalds@linux-foundation.org>2017-11-18 02:45:29 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-18 02:45:29 +0100
commit09bd7c75e55cbaa6c731b0c3a5512ad89159f26f (patch)
treea73bd9f94d7661d6ff82f3374d4efea81925f7c8 /scripts/Makefile.build
parentMerge branch 'akpm' (patches from Andrew) (diff)
parentkbuild: move coccicheck help from scripts/Makefile.help to top Makefile (diff)
downloadlinux-09bd7c75e55cbaa6c731b0c3a5512ad89159f26f.tar.xz
linux-09bd7c75e55cbaa6c731b0c3a5512ad89159f26f.zip
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 $(wildcard ...) for cmd_files calculation kbuild: create directory for make cache only when necessary sh: select KBUILD_DEFCONFIG depending on ARCH kbuild: fix linker feature test macros when cross compiling with Clang kbuild: shrink .cache.mk when it exceeds 1000 lines kbuild: do not call cc-option before KBUILD_CFLAGS initialization kbuild: Cache a few more calls to the compiler kbuild: Add a cache for generated variables kbuild: add forward declaration of default target to Makefile.asm-generic kbuild: remove KBUILD_SUBDIR_ASFLAGS and KBUILD_SUBDIR_CCFLAGS hexagon/kbuild: replace CFLAGS_MODULE with KBUILD_CFLAGS_MODULE ...
Diffstat (limited to 'scripts/Makefile.build')
-rw-r--r--scripts/Makefile.build25
1 files changed, 13 insertions, 12 deletions
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index e63af4e19382..f171225383cc 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -65,15 +65,6 @@ ifneq ($(hostprogs-y)$(hostprogs-m)$(hostlibs-y)$(hostlibs-m)$(hostcxxlibs-y)$(h
include scripts/Makefile.host
endif
-ifneq ($(KBUILD_SRC),)
-# Create output directory if not already present
-_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
-
-# Create directories for object files if directory does not exist
-# Needed when obj-y := dir/file.o syntax is used
-_dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))
-endif
-
ifndef obj
$(warning kbuild: Makefile.build is included improperly)
endif
@@ -563,7 +554,7 @@ $(multi-used-m): FORCE
$(call multi_depend, $(multi-used-m), .o, -objs -y -m)
targets += $(multi-used-y) $(multi-used-m)
-
+targets := $(filter-out $(PHONY), $(targets))
# Descending
# ---------------------------------------------------------------------------
@@ -584,13 +575,23 @@ FORCE:
# optimization, we don't need to read them if the target does not
# exist, we will rebuild anyway in that case.
-targets := $(wildcard $(sort $(targets)))
-cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
+cmd_files := $(wildcard $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd))
ifneq ($(cmd_files),)
include $(cmd_files)
endif
+ifneq ($(KBUILD_SRC),)
+# Create directories for object files if they do not exist
+obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets))))
+# If cmd_files exist, their directories apparently exist. Skip mkdir.
+exist-dirs := $(sort $(patsubst %/,%, $(dir $(cmd_files))))
+obj-dirs := $(strip $(filter-out $(exist-dirs), $(obj-dirs)))
+ifneq ($(obj-dirs),)
+$(shell mkdir -p $(obj-dirs))
+endif
+endif
+
# Declare the contents of the .PHONY variable as phony. We keep that
# information in a variable se we can use it in if_changed and friends.