kbuild: check the minimum compiler version in Kconfig
Paul Gortmaker reported a regression in the GCC version check. [1]
If you use GCC 4.8, the build breaks before showing the error message
"error Sorry, your version of GCC is too old - please use 4.9 or newer."
I do not want to apply his fix-up since it implies we would not be able
to remove any cc-option test. Anyway, I admit checking the GCC version
in <linux/compiler-gcc.h> is too late.
Almost at the same time, Linus also suggested to move the compiler
version error to Kconfig time. [2]
I unified the two similar scripts, gcc-version.sh and clang-version.sh
into cc-version.sh. The old scripts invoked the compiler multiple times
(3 times for gcc-version.sh, 4 times for clang-version.sh). I refactored
the code so the new one invokes the compiler just once, and also tried
my best to use shell-builtin commands where possible.
The new script runs faster.
$ time ./scripts/clang-version.sh clang
120000
real 0m0.029s
user 0m0.012s
sys 0m0.021s
$ time ./scripts/cc-version.sh clang
Clang 120000
real 0m0.009s
user 0m0.006s
sys 0m0.004s
cc-version.sh also shows an error message if the compiler is too old:
$ make defconfig CC=clang-9
*** Default configuration is based on 'x86_64_defconfig'
***
*** Compiler is too old.
*** Your Clang version: 9.0.1
*** Minimum Clang version: 10.0.1
***
scripts/Kconfig.include:46: Sorry, this compiler is not supported.
make[1]: *** [scripts/kconfig/Makefile:81: defconfig] Error 1
make: *** [Makefile:602: defconfig] Error 2
The new script takes care of ICC because we have <linux/compiler-intel.h>
although I am not sure if building the kernel with ICC is well-supported.
[1]: https://lore.kernel.org/r/20210110190807.134996-1-paul.gortmaker@windriver.com
[2]: https://lore.kernel.org/r/CAHk-=wh-+TMHPTFo1qs-MYyK7tZh-OQovA=pP3=e06aCVp6_kA@mail.gmail.com
Fixes: 87de84c9140e ("kbuild: remove cc-option test of -Werror=date-time")
Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
diff --git a/scripts/cc-version.sh b/scripts/cc-version.sh
new file mode 100755
index 0000000..3f2ee88
--- /dev/null
+++ b/scripts/cc-version.sh
@@ -0,0 +1,82 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Print the compiler name and its version in a 5 or 6-digit form.
+# Also, perform the minimum version check.
+
+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 [ "$SRCARCH" = arm64 ]; then
+ gcc_min_version=5.1.0
+fi
+
+# Print the compiler name and some version components.
+get_compiler_info()
+{
+ cat <<- EOF | "$@" -E -P -x c - 2>/dev/null
+ #if defined(__clang__)
+ Clang __clang_major__ __clang_minor__ __clang_patchlevel__
+ #elif defined(__INTEL_COMPILER)
+ ICC __INTEL_COMPILER __INTEL_COMPILER_UPDATE
+ #elif defined(__GNUC__)
+ GCC __GNUC__ __GNUC_MINOR__ __GNUC_PATCHLEVEL__
+ #else
+ unknown
+ #endif
+ EOF
+}
+
+# Convert the version string x.y.z to a canonical 5 or 6-digit form.
+get_canonical_version()
+{
+ IFS=.
+ set -- $1
+ echo $((10000 * $1 + 100 * $2 + $3))
+}
+
+# $@ instead of $1 because multiple words might be given, e.g. CC="ccache gcc".
+orig_args="$@"
+set -- $(get_compiler_info "$@")
+
+name=$1
+
+case "$name" in
+GCC)
+ version=$2.$3.$4
+ min_version=$gcc_min_version
+ ;;
+Clang)
+ version=$2.$3.$4
+ min_version=$clang_min_version
+ ;;
+ICC)
+ version=$(($2 / 100)).$(($2 % 100)).$3
+ min_version=$icc_min_version
+ ;;
+*)
+ echo "$orig_args: unknown compiler" >&2
+ exit 1
+ ;;
+esac
+
+cversion=$(get_canonical_version $version)
+min_cversion=$(get_canonical_version $min_version)
+
+if [ "$cversion" -lt "$min_cversion" ]; then
+ echo >&2 "***"
+ echo >&2 "*** Compiler is too old."
+ echo >&2 "*** Your $name version: $version"
+ echo >&2 "*** Minimum $name version: $min_version"
+ echo >&2 "***"
+ exit 1
+fi
+
+echo $name $cversion