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authorNick Desaulniers <ndesaulniers@google.com>2021-02-05 14:01:25 -0800
committerMasahiro Yamada <masahiroy@kernel.org>2021-02-24 15:11:17 +0900
commitdb07562aeac77923370bff4733d8b0e09cbc93c4 (patch)
treeb69799d84344cbf543cbf5b810c56e7c2f93d18c /Makefile
parent02aff85922043cf175ebbe5fc3430acfeaeb8393 (diff)
downloadlinux-db07562aeac77923370bff4733d8b0e09cbc93c4.tar.bz2
Makefile: reuse CC_VERSION_TEXT
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 $(findstring ) will give real performance benefit.] Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile14
1 files changed, 7 insertions, 7 deletions
diff --git a/Makefile b/Makefile
index 1fdd44fe1659..6c3a2064072d 100644
--- a/Makefile
+++ b/Makefile
@@ -557,7 +557,13 @@ ifdef building_out_of_srctree
{ echo "# this is build directory, ignore it"; echo "*"; } > .gitignore
endif
-ifneq ($(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),)
CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%))
GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
@@ -576,12 +582,6 @@ KBUILD_AFLAGS += $(CLANG_FLAGS)
export CLANG_FLAGS
endif
-# The expansion should be delayed until arch/$(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
# ===========================================================================
# *config targets only - make sure prerequisites are updated, and descend