mirrors/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2025-10-31 16:48:26 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

kbuild: check the minimum compiler version in Kconfig

Browse source 
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: 87de84c914 ("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>
This commit is contained in:
Masahiro Yamada 2021-01-16 08:35:42 +09:00
parent 052c805a18
commit aec6c60a01
8 changed files with 93 additions and 65 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

1
MAINTAINERS
View file

@ -4314,7 +4314,6 @@ C: irc://chat.freenode.net/clangbuiltlinux
F: Documentation/kbuild/llvm.rst
F: include/linux/compiler-clang.h
F: scripts/clang-tools/
F: scripts/clang-version.sh
F: scripts/lld-version.sh
K: \b(?i:clang|llvm)\b

10
include/linux/compiler-clang.h
View file

@ -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

11
include/linux/compiler-gcc.h
View file

@ -10,17 +10,6 @@
+ __GNUC_MINOR__ * 100 \
+ __GNUC_PATCHLEVEL__)
/* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 */
#if GCC_VERSION < 40900
# error Sorry, your version of GCC is too old - please use 4.9 or newer.
#elif defined(CONFIG_ARM64) && GCC_VERSION < 50100
/*
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293
* https://lore.kernel.org/r/20210107111841.GN1551@shell.armlinux.org.uk
*/
# error Sorry, your version of GCC is too old - please use 5.1 or newer.
#endif
/*
* This macro obfuscates arithmetic on a variable address so that gcc
* shouldn't recognize the original var, and make assumptions about it.

9
init/Kconfig
View file

@ -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

6
scripts/Kconfig.include
View file

@ -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 not supported.
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)

82
scripts/cc-version.sh Executable file
View file

@ -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

19
scripts/clang-version.sh
View file

@ -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

20
scripts/gcc-version.sh
View file

@ -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