From: Masahiro Yamada Date: Mon, 15 Mar 2021 16:12:56 +0000 (+0900) Subject: kbuild: check the minimum assembler version in Kconfig X-Git-Tag: accepted/tizen/unified/20230118.172025~7334^2~28 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ba64beb17493a4bfec563100c86a462a15926f24;p=platform%2Fkernel%2Flinux-rpi.git kbuild: check the minimum assembler version in Kconfig Documentation/process/changes.rst defines the minimum assembler version (binutils version), but we have never checked it in the build time. Kbuild never invokes 'as' directly because all assembly files in the kernel tree are *.S, hence must be preprocessed. I do not expect raw assembly source files (*.s) would be added to the kernel tree. Therefore, we always use $(CC) as the assembler driver, and commit aa824e0c962b ("kbuild: remove AS variable") removed 'AS'. However, we are still interested in the version of the assembler acting behind. As usual, the --version option prints the version string. $ as --version | head -n 1 GNU assembler (GNU Binutils for Ubuntu) 2.35.1 But, we do not have $(AS). So, we can add the -Wa prefix so that $(CC) passes --version down to the backing assembler. $ gcc -Wa,--version | head -n 1 gcc: fatal error: no input files compilation terminated. OK, we need to input something to satisfy gcc. $ gcc -Wa,--version -c -x assembler /dev/null -o /dev/null | head -n 1 GNU assembler (GNU Binutils for Ubuntu) 2.35.1 The combination of Clang and GNU assembler works in the same way: $ clang -no-integrated-as -Wa,--version -c -x assembler /dev/null -o /dev/null | head -n 1 GNU assembler (GNU Binutils for Ubuntu) 2.35.1 Clang with the integrated assembler fails like this: $ clang -integrated-as -Wa,--version -c -x assembler /dev/null -o /dev/null | head -n 1 clang: error: unsupported argument '--version' to option 'Wa,' For the last case, checking the error message is fragile. If the proposal for -Wa,--version support [1] is accepted, this may not be even an error in the future. One easy way is to check if -integrated-as is present in the passed arguments. We did not pass -integrated-as to CLANG_FLAGS before, but we can make it explicit. Nathan pointed out -integrated-as is the default for all of the architectures/targets that the kernel cares about, but it goes along with "explicit is better than implicit" policy. [2] With all this in my mind, I implemented scripts/as-version.sh to check the assembler version in Kconfig time. $ scripts/as-version.sh gcc GNU 23501 $ scripts/as-version.sh clang -no-integrated-as GNU 23501 $ scripts/as-version.sh clang -integrated-as LLVM 0 [1]: https://github.com/ClangBuiltLinux/linux/issues/1320 [2]: https://lore.kernel.org/linux-kbuild/20210307044253.v3h47ucq6ng25iay@archlinux-ax161/ Signed-off-by: Masahiro Yamada Reviewed-by: Nathan Chancellor --- diff --git a/Makefile b/Makefile index cc5b7e3..2b161f5 100644 --- a/Makefile +++ b/Makefile @@ -580,7 +580,9 @@ ifneq ($(findstring clang,$(CC_VERSION_TEXT)),) ifneq ($(CROSS_COMPILE),) CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%)) endif -ifneq ($(LLVM_IAS),1) +ifeq ($(LLVM_IAS),1) +CLANG_FLAGS += -integrated-as +else CLANG_FLAGS += -no-integrated-as GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit)) CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE)) diff --git a/arch/Kconfig b/arch/Kconfig index ecfd352..555b4f0 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -631,8 +631,7 @@ config ARCH_SUPPORTS_LTO_CLANG_THIN config HAS_LTO_CLANG def_bool y # Clang >= 11: https://github.com/ClangBuiltLinux/linux/issues/510 - depends on CC_IS_CLANG && CLANG_VERSION >= 110000 && LD_IS_LLD - depends on $(success,test $(LLVM_IAS) -eq 1) + depends on CC_IS_CLANG && CLANG_VERSION >= 110000 && LD_IS_LLD && AS_IS_LLVM depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm) depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm) depends on ARCH_SUPPORTS_LTO_CLANG diff --git a/init/Kconfig b/init/Kconfig index 5f5c776..019c187 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -41,6 +41,18 @@ config CLANG_VERSION default $(cc-version) if CC_IS_CLANG default 0 +config AS_IS_GNU + def_bool $(success,test "$(as-name)" = GNU) + +config AS_IS_LLVM + def_bool $(success,test "$(as-name)" = LLVM) + +config AS_VERSION + int + # Use clang version if this is the integrated assembler + default CLANG_VERSION if AS_IS_LLVM + default $(as-version) + config LD_IS_BFD def_bool $(success,test "$(ld-name)" = BFD) diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include index 58fdb53..0496efd 100644 --- a/scripts/Kconfig.include +++ b/scripts/Kconfig.include @@ -45,6 +45,12 @@ $(error-if,$(success,test -z "$(cc-info)"),Sorry$(comma) this compiler is not su cc-name := $(shell,set -- $(cc-info) && echo $1) cc-version := $(shell,set -- $(cc-info) && echo $2) +# Get the assembler name, version, and error out if it is not supported. +as-info := $(shell,$(srctree)/scripts/as-version.sh $(CC) $(CLANG_FLAGS)) +$(error-if,$(success,test -z "$(as-info)"),Sorry$(comma) this assembler is not supported.) +as-name := $(shell,set -- $(as-info) && echo $1) +as-version := $(shell,set -- $(as-info) && echo $2) + # Get the linker name, version, and error out if it is not supported. ld-info := $(shell,$(srctree)/scripts/ld-version.sh $(LD)) $(error-if,$(success,test -z "$(ld-info)"),Sorry$(comma) this linker is not supported.) diff --git a/scripts/as-version.sh b/scripts/as-version.sh new file mode 100755 index 0000000..8b9410e --- /dev/null +++ b/scripts/as-version.sh @@ -0,0 +1,82 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0-only +# +# Print the assembler name and its version in a 5 or 6-digit form. +# Also, perform the minimum version check. +# (If it is the integrated assembler, return 0 as the version, and +# skip the version check.) + +set -e + +# Convert the version string x.y.z to a canonical 5 or 6-digit form. +get_canonical_version() +{ + IFS=. + set -- $1 + + # If the 2nd or 3rd field is missing, fill it with a zero. + # + # The 4th field, if present, is ignored. + # This occurs in development snapshots as in 2.35.1.20201116 + echo $((10000 * $1 + 100 * ${2:-0} + ${3:-0})) +} + +# Clang fails to handle -Wa,--version unless -no-integrated-as is given. +# We check -(f)integrated-as, expecting it is explicitly passed in for the +# integrated assembler case. +check_integrated_as() +{ + while [ $# -gt 0 ]; do + if [ "$1" = -integrated-as -o "$1" = -fintegrated-as ]; then + # For the intergrated assembler, we do not check the + # version here. It is the same as the clang version, and + # it has been already checked by scripts/cc-version.sh. + echo LLVM 0 + exit 0 + fi + shift + done +} + +check_integrated_as "$@" + +orig_args="$@" + +# Get the first line of the --version output. +IFS=' +' +set -- $(LC_ALL=C "$@" -Wa,--version -c -x assembler /dev/null -o /dev/null 2>/dev/null) + +# Split the line on spaces. +IFS=' ' +set -- $1 + +min_tool_version=$(dirname $0)/min-tool-version.sh + +if [ "$1" = GNU -a "$2" = assembler ]; then + shift $(($# - 1)) + version=$1 + min_version=$($min_tool_version binutils) + name=GNU +else + echo "$orig_args: unknown assembler invoked" >&2 + exit 1 +fi + +# Some distributions append a package release number, as in 2.34-4.fc32 +# Trim the hyphen and any characters that follow. +version=${version%-*} + +cversion=$(get_canonical_version $version) +min_cversion=$(get_canonical_version $min_version) + +if [ "$cversion" -lt "$min_cversion" ]; then + echo >&2 "***" + echo >&2 "*** Assembler is too old." + echo >&2 "*** Your $name assembler version: $version" + echo >&2 "*** Minimum $name assembler version: $min_version" + echo >&2 "***" + exit 1 +fi + +echo $name $cversion diff --git a/scripts/dummy-tools/gcc b/scripts/dummy-tools/gcc index 39e65fe..f6d5437 100755 --- a/scripts/dummy-tools/gcc +++ b/scripts/dummy-tools/gcc @@ -67,6 +67,12 @@ if arg_contain -E "$@"; then fi fi +# To set CONFIG_AS_IS_GNU +if arg_contain -Wa,--version "$@"; then + echo "GNU assembler (scripts/dummy-tools) 2.50" + exit 0 +fi + if arg_contain -S "$@"; then # For scripts/gcc-x86-*-has-stack-protector.sh if arg_contain -fstack-protector "$@"; then