[PATCH v3] kbuild: check the minimum compiler version in Kconfig
From: Masahiro Yamada
Date: Thu Jan 14 2021 - 13:09:47 EST
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 similar two scripts, gcc-version.sh and clang-version.sh
into the new 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
The cc-version.sh also shows the error if the compiler is 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
I removed the clang version check from <linux/compiler-clang.h>
For now, I did not touch <linux/compiler-gcc.h> in order to avoid
merge conflict with [3], which has been queued up in the arm64 tree.
We will be able to clean it up later.
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://lkml.org/lkml/2021/1/10/250
[2] https://lkml.org/lkml/2021/1/12/1708
[3] https://lkml.org/lkml/2021/1/12/1533
Fixes: 87de84c9140e ("kbuild: remove cc-option test of -Werror=date-time")
Reported-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---
Changes in v3:
- add $(srctree)/ to fix out-of-tree build
- support ICC version
Changes in v2:
- fix the function name
include/linux/compiler-clang.h | 10 -----
init/Kconfig | 9 ++--
scripts/Kconfig.include | 6 +++
scripts/cc-version.sh | 76 ++++++++++++++++++++++++++++++++++
scripts/clang-version.sh | 19 ---------
scripts/gcc-version.sh | 20 ---------
6 files changed, 87 insertions(+), 53 deletions(-)
create mode 100755 scripts/cc-version.sh
delete mode 100755 scripts/clang-version.sh
delete mode 100755 scripts/gcc-version.sh
diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
index 98cff1b4b088..04c0a5a717f7 100644
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -3,16 +3,6 @@
#error "Please don't include <linux/compiler-clang.h> directly, include <linux/compiler.h> instead."
#endif
-#define CLANG_VERSION (__clang_major__ * 10000 \
- + __clang_minor__ * 100 \
- + __clang_patchlevel__)
-
-#if CLANG_VERSION < 100001
-#ifndef __BPF_TRACING__
-# error Sorry, your version of Clang is too old - please use 10.0.1 or newer.
-#endif
-#endif
-
/* Compiler specific definitions for Clang compiler */
/* same as gcc, this was present in clang-2.6 so we can assume it works
diff --git a/init/Kconfig b/init/Kconfig
index b77c60f8b963..01108dd1318b 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -26,11 +26,11 @@ config CC_VERSION_TEXT
and then every file will be rebuilt.
config CC_IS_GCC
- def_bool $(success,echo "$(CC_VERSION_TEXT)" | grep -q gcc)
+ def_bool $(success,test $(cc-name) = GCC)
config GCC_VERSION
int
- default $(shell,$(srctree)/scripts/gcc-version.sh $(CC)) if CC_IS_GCC
+ default $(cc-version) if CC_IS_GCC
default 0
config LD_VERSION
@@ -38,14 +38,15 @@ config LD_VERSION
default $(shell,$(LD) --version | $(srctree)/scripts/ld-version.sh)
config CC_IS_CLANG
- def_bool $(success,echo "$(CC_VERSION_TEXT)" | grep -q clang)
+ def_bool $(success,test $(cc-name) = Clang)
config LD_IS_LLD
def_bool $(success,$(LD) -v | head -n 1 | grep -q LLD)
config CLANG_VERSION
int
- default $(shell,$(srctree)/scripts/clang-version.sh $(CC))
+ default $(cc-version) if CC_IS_CLANG
+ default 0
config LLD_VERSION
int
diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
index a5fe72c504ff..26c355a84c19 100644
--- a/scripts/Kconfig.include
+++ b/scripts/Kconfig.include
@@ -39,6 +39,12 @@ as-instr = $(success,printf "%b\n" "$(1)" | $(CC) $(CLANG_FLAGS) -c -x assembler
$(error-if,$(failure,command -v $(CC)),compiler '$(CC)' not found)
$(error-if,$(failure,command -v $(LD)),linker '$(LD)' not found)
+# Get the compiler name, version, and error out if it is unsupported.
+cc-info := $(shell,$(srctree)/scripts/cc-version.sh $(CC))
+$(error-if,$(success,test -z "$(cc-info)"),Sorry$(comma) this compiler is not supported.)
+cc-name := $(shell,set -- $(cc-info) && echo $1)
+cc-version := $(shell,set -- $(cc-info) && echo $2)
+
# Fail if the linker is gold as it's not capable of linking the kernel proper
$(error-if,$(success, $(LD) -v | grep -q gold), gold linker '$(LD)' not supported)
diff --git a/scripts/cc-version.sh b/scripts/cc-version.sh
new file mode 100755
index 000000000000..818d233bb0ad
--- /dev/null
+++ b/scripts/cc-version.sh
@@ -0,0 +1,76 @@
+#!/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 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
+
+# print the compiler name and versions
+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 $cversion
diff --git a/scripts/clang-version.sh b/scripts/clang-version.sh
deleted file mode 100755
index 6fabf0695761..000000000000
--- a/scripts/clang-version.sh
+++ /dev/null
@@ -1,19 +0,0 @@
-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0
-#
-# clang-version clang-command
-#
-# Print the compiler version of `clang-command' in a 5 or 6-digit form
-# such as `50001' for clang-5.0.1 etc.
-
-compiler="$*"
-
-if ! ( $compiler --version | grep -q clang) ; then
- echo 0
- exit 1
-fi
-
-MAJOR=$(echo __clang_major__ | $compiler -E -x c - | tail -n 1)
-MINOR=$(echo __clang_minor__ | $compiler -E -x c - | tail -n 1)
-PATCHLEVEL=$(echo __clang_patchlevel__ | $compiler -E -x c - | tail -n 1)
-printf "%d%02d%02d\\n" $MAJOR $MINOR $PATCHLEVEL
diff --git a/scripts/gcc-version.sh b/scripts/gcc-version.sh
deleted file mode 100755
index ae353432539b..000000000000
--- a/scripts/gcc-version.sh
+++ /dev/null
@@ -1,20 +0,0 @@
-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0
-#
-# gcc-version gcc-command
-#
-# Print the gcc version of `gcc-command' in a 5 or 6-digit form
-# such as `29503' for gcc-2.95.3, `30301' for gcc-3.3.1, etc.
-
-compiler="$*"
-
-if [ ${#compiler} -eq 0 ]; then
- echo "Error: No compiler specified." >&2
- printf "Usage:\n\t$0 <gcc-command>\n" >&2
- exit 1
-fi
-
-MAJOR=$(echo __GNUC__ | $compiler -E -x c - | tail -n 1)
-MINOR=$(echo __GNUC_MINOR__ | $compiler -E -x c - | tail -n 1)
-PATCHLEVEL=$(echo __GNUC_PATCHLEVEL__ | $compiler -E -x c - | tail -n 1)
-printf "%d%02d%02d\\n" $MAJOR $MINOR $PATCHLEVEL
--
2.27.0