kbuild: collect minimum tool versions into scripts/min-tool-version.sh

The kernel build uses various tools, many of which are provided by the
same software suite, for example, LLVM and Binutils.

When you raise the minimum version of Clang/LLVM, you need to update
clang_min_version in scripts/cc-version.sh and also lld_min_version in
scripts/ld-version.sh.

Kbuild can handle CC=clang and LD=ld.lld independently, but it does not
make much sense to maintain their versions separately.

Let's create a central place of minimum tool versions so you do not need
to touch multiple files. scripts/min-tool-version.sh prints the minimum
version of the given tool.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>

scripts/cc-version.sh

@@ -6,18 +6,6 @@
 
 set -e
 
-# When you raise the minimum compiler version, please update
-# Documentation/process/changes.rst as well.
-gcc_min_version=4.9.0
-clang_min_version=10.0.1
-icc_min_version=16.0.3 # temporary
-
-# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293
-# https://lore.kernel.org/r/20210107111841.GN1551@shell.armlinux.org.uk
-if [ "$SRCARCH" = arm64 ]; then
-	gcc_min_version=5.1.0
-fi
-
 # Print the compiler name and some version components.
 get_compiler_info()
 {
@@ -48,18 +36,20 @@ set -- $(get_compiler_info "$@")
 
 name=$1
 
+min_tool_version=$(dirname $0)/min-tool-version.sh
+
 case "$name" in
 GCC)
 	version=$2.$3.$4
-	min_version=$gcc_min_version
+	min_version=$($min_tool_version gcc)
 	;;
 Clang)
 	version=$2.$3.$4
-	min_version=$clang_min_version
+	min_version=$($min_tool_version llvm)
 	;;
 ICC)
 	version=$(($2 / 100)).$(($2 % 100)).$3
-	min_version=$icc_min_version
+	min_version=$($min_tool_version icc)
 	;;
 *)
 	echo "$orig_args: unknown compiler" >&2

scripts/ld-version.sh

@@ -6,11 +6,6 @@
 
 set -e
 
-# When you raise the minimum linker version, please update
-# Documentation/process/changes.rst as well.
-bfd_min_version=2.23.0
-lld_min_version=10.0.1
-
 # Convert the version string x.y.z to a canonical 5 or 6-digit form.
 get_canonical_version()
 {
@@ -35,10 +30,12 @@ set -- $(LC_ALL=C "$@" --version)
 IFS=' '
 set -- $1
 
+min_tool_version=$(dirname $0)/min-tool-version.sh
+
 if [ "$1" = GNU -a "$2" = ld ]; then
 	shift $(($# - 1))
 	version=$1
-	min_version=$bfd_min_version
+	min_version=$($min_tool_version binutils)
 	name=BFD
 	disp_name="GNU ld"
 elif [ "$1" = GNU -a "$2" = gold ]; then
@@ -51,7 +48,7 @@ else
 
 	if [ "$1" = LLD ]; then
 		version=$2
-		min_version=$lld_min_version
+		min_version=$($min_tool_version llvm)
 		name=LLD
 		disp_name=LLD
 	else

scripts/min-tool-version.sh

@@ -0,0 +1,39 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Print the minimum supported version of the given tool.
+# When you raise the minimum version, please update
+# Documentation/process/changes.rst as well.
+
+set -e
+
+if [ $# != 1 ]; then
+	echo "Usage: $0 toolname" >&2
+	exit 1
+fi
+
+case "$1" in
+binutils)
+	echo 2.23.0
+	;;
+gcc)
+	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293
+	# https://lore.kernel.org/r/20210107111841.GN1551@shell.armlinux.org.uk
+	if [ "$SRCARCH" = arm64 ]; then
+		echo 5.1.0
+	else
+		echo 4.9.0
+	fi
+	;;
+icc)
+	# temporary
+	echo 16.0.3
+	;;
+llvm)
+	echo 10.0.1
+	;;
+*)
+	echo "$1: unknown tool" >&2
+	exit 1
+	;;
+esac