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Makefile: reuse CC_VERSION_TEXT

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I noticed we're invoking $(CC) via $(shell) more than once to check the
version.  Let's reuse the first string captured in $CC_VERSION_TEXT.

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
[masahiro.yamada:
CC_VERSION_TEXT is assigned by = instead of :=, so this $(shell ) is
evaluated multiple times anyway. The number of $(CC) invocations will
be still the same. Replacing 'grep' with the built-in $(findstring )
will give real performance benefit.]
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This commit is contained in:
Nick Desaulniers 2021-02-05 14:01:25 -08:00 committed by Masahiro Yamada
parent 02aff85922
commit db07562aea
1 changed files with 7 additions and 7 deletions
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14
Makefile
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@ -557,7 +557,13 @@ ifdef building_out_of_srctree
{ echo "# this is build directory, ignore it"; echo "*"; } > .gitignore { echo "# this is build directory, ignore it"; echo "*"; } > .gitignore
endif endif
ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),) # The expansion should be delayed until arch/$(SRCARCH)/Makefile is included.
# Some architectures define CROSS_COMPILE in arch/$(SRCARCH)/Makefile.
# CC_VERSION_TEXT is referenced from Kconfig (so it needs export),
# and from include/config/auto.conf.cmd to detect the compiler upgrade.
CC_VERSION_TEXT = $(shell $(CC) --version 2>/dev/null | head -n 1)
ifneq ($(findstring clang,$(CC_VERSION_TEXT)),)
ifneq ($(CROSS_COMPILE),) ifneq ($(CROSS_COMPILE),)
CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%)) CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%))
GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit)) GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
@ -576,12 +582,6 @@ KBUILD_AFLAGS += $(CLANG_FLAGS)
export CLANG_FLAGS export CLANG_FLAGS
endif endif
# The expansion should be delayed until arch/$(SRCARCH)/Makefile is included.
# Some architectures define CROSS_COMPILE in arch/$(SRCARCH)/Makefile.
# CC_VERSION_TEXT is referenced from Kconfig (so it needs export),
# and from include/config/auto.conf.cmd to detect the compiler upgrade.
CC_VERSION_TEXT = $(shell $(CC) --version 2>/dev/null | head -n 1)
ifdef config-build ifdef config-build
# =========================================================================== # ===========================================================================
# *config targets only - make sure prerequisites are updated, and descend # *config targets only - make sure prerequisites are updated, and descend