[PATCH] selftests: kselftest_deps.sh: Support LLVM

[PATCH] selftests: kselftest_deps.sh: Support LLVM

[Mark Brown]

The kselftest_deps.sh script currently takes a compiler as the first
argument and uses it to check that libraries needed by the selftests
are installed.  This works well for GCC where a separate binary is
provided for each target architecture but is less of a good fit for
LLVM where a single compiler binary can target all of the supported
architetures.  Extend the script to accept "LLVM" as the compiler with
an additional optional ARCH= argument so that it can be used when
building with LLVM in a similar fashion to how the actual build works.

The duplication with the main Makefile isn't ideal here.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/kselftest_deps.sh | 83 +++++++++++++++++++++++++++++--
 1 file changed, 80 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/kselftest_deps.sh b/tools/testing/selftests/kselftest_deps.sh
index 487e49fdf2a6..70b834361cb7 100755
--- a/tools/testing/selftests/kselftest_deps.sh
+++ b/tools/testing/selftests/kselftest_deps.sh
@@ -10,13 +10,20 @@
 usage()
 {
 
-echo -e "Usage: $0 -[p] <compiler> [test_name]\n"
+echo -e "Usage: $0 -[p] <compiler> [ARCH=<arch>] [test_name]\n"
 echo -e "\tkselftest_deps.sh [-p] gcc"
 echo -e "\tkselftest_deps.sh [-p] gcc mm"
 echo -e "\tkselftest_deps.sh [-p] aarch64-linux-gnu-gcc"
-echo -e "\tkselftest_deps.sh [-p] aarch64-linux-gnu-gcc mm\n"
+echo -e "\tkselftest_deps.sh [-p] aarch64-linux-gnu-gcc mm"
+echo -e "\tkselftest_deps.sh [-p] LLVM"
+echo -e "\tkselftest_deps.sh [-p] LLVM ARCH=arm64 mm\n"
 echo "- Should be run in selftests directory in the kernel repo."
 echo "- Checks if Kselftests can be built/cross-built on a system."
+echo "- Compiler can be given as LLVM to use clang, as with LLVM=1 in"
+echo "  the kselftest build. LLVM=<prefix>/ and LLVM=-<suffix> select"
+echo "  the clang binary as in the kselftest build. ARCH=<arch> selects"
+echo "  the clang target architecture, defaulting to the host; it is"
+echo "  ignored for other compilers."
 echo "- Parses all test/sub-test Makefile to find library dependencies."
 echo "- Runs compile test on a trivial C file with LDLIBS specified"
 echo "  in the test Makefiles to identify missing library dependencies."
@@ -53,13 +60,32 @@ while getopts "p" arg; do
 	esac
 done
 
+# Pull an optional ARCH=<arch> out of the remaining arguments. The
+# environment is used if it is not given on the command line, as with
+# make.
+args=()
+for arg in "$@"; do
+	case "$arg" in
+		ARCH=*)
+		ARCH=${arg#ARCH=};;
+		*)
+		args+=("$arg");;
+	esac
+done
+set -- "${args[@]}"
+
 if [ $# -eq 0 ]
 then
 	usage
 fi
 
 # Compiler
-CC=$1
+case "$1" in
+	LLVM|LLVM=*)
+	setup_llvm "${1#LLVM}";;
+	*)
+	CC=$1;;
+esac
 
 tmp_file=$(mktemp).c
 trap "rm -f $tmp_file.o $tmp_file $tmp_file.bin" EXIT
@@ -178,6 +204,56 @@ exit $?
 }
 # end main()
 
+# Mirror the LLVM handling in lib.mk: LLVM=<prefix>/ or LLVM=-<suffix>
+# select the clang binary, and ARCH selects the target triple with the
+# host as the default.
+setup_llvm()
+{
+	local llvm=${1#=}
+	local llvm_prefix=""
+	local llvm_suffix=""
+	local clang
+	local target
+
+	declare -A clang_target
+	clang_target[arm]=arm-linux-gnueabi
+	clang_target[arm64]=aarch64-linux-gnu
+	clang_target[hexagon]=hexagon-linux-musl
+	clang_target[i386]=i386-linux-gnu
+	clang_target[m68k]=m68k-linux-gnu
+	clang_target[mips]=mipsel-linux-gnu
+	clang_target[powerpc]=powerpc64le-linux-gnu
+	clang_target[riscv]=riscv64-linux-gnu
+	clang_target[s390]=s390x-linux-gnu
+	clang_target[x86]=x86_64-linux-gnu
+	clang_target[x86_64]=x86_64-linux-gnu
+
+	case "$llvm" in
+		*/)
+		llvm_prefix=$llvm;;
+		-*)
+		llvm_suffix=$llvm;;
+	esac
+	clang=${llvm_prefix}clang${llvm_suffix}
+
+	if [ -z "$ARCH" ]; then
+		target=$($clang -print-target-triple 2>/dev/null)
+		if [ -z "$target" ]; then
+			echo -e "\tUnable to run $clang ..."
+			exit 1
+		fi
+	else
+		target=${clang_target[$ARCH]}
+		if [ -z "$target" ]; then
+			echo -e "\tUnknown ARCH $ARCH for LLVM, supported:"
+			echo -e "\t$(echo "${!clang_target[*]}" | xargs -n1 | sort | xargs)"
+			exit 1
+		fi
+	fi
+
+	CC="$clang --target=$target -fintegrated-as"
+}
+
 all_tests()
 {
 	for test in $l1_tests; do
@@ -285,6 +361,7 @@ print_results()
 {
 	echo -e "========================================================";
 	echo -e "Kselftest Dependency Check for [$0 $1 $2] results..."
+	echo -e "Compiler: $CC"
 
 	if [ $print_targets -ne 0 ]
 	then

---
base-commit: 24a19b953e2a3d0ea5a8c4951a0ab8f32720c907
base-tree: git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm master
change-id: 20261013-kselftest-deps-llvm-51be8d160008

Best regards,
--  
Mark Brown <broonie@kernel.org>

Re: [PATCH] selftests: kselftest_deps.sh: Support LLVM

[Shuah Khan]

On 10/13/26 13:40, Mark Brown wrote:
> The kselftest_deps.sh script currently takes a compiler as the first
> argument and uses it to check that libraries needed by the selftests
> are installed.  This works well for GCC where a separate binary is
> provided for each target architecture but is less of a good fit for
> LLVM where a single compiler binary can target all of the supported
> architetures.  Extend the script to accept "LLVM" as the compiler with
> an additional optional ARCH= argument so that it can be used when
> building with LLVM in a similar fashion to how the actual build works.
> 
> The duplication with the main Makefile isn't ideal here.
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
>   tools/testing/selftests/kselftest_deps.sh | 83 +++++++++++++++++++++++++++++--
>   1 file changed, 80 insertions(+), 3 deletions(-)
> 

Thank you Mark.

Looks good to me. I will wait for others to chime in and will
apply this for 7.4-rc1

thanks,
-- Shuah

Re: [PATCH] selftests: kselftest_deps.sh: Support LLVM

[Nick Desaulniers]

On Tue, Oct 13, 2026 at 12:40 PM Mark Brown <broonie@kernel.org> wrote:
>
> The kselftest_deps.sh script currently takes a compiler as the first
> argument and uses it to check that libraries needed by the selftests
> are installed.  This works well for GCC where a separate binary is
> provided for each target architecture but is less of a good fit for
> LLVM where a single compiler binary can target all of the supported
> architetures.  Extend the script to accept "LLVM" as the compiler with
> an additional optional ARCH= argument so that it can be used when
> building with LLVM in a similar fashion to how the actual build works.
>
> The duplication with the main Makefile isn't ideal here.
>
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
>  tools/testing/selftests/kselftest_deps.sh | 83 +++++++++++++++++++++++++++++--
>  1 file changed, 80 insertions(+), 3 deletions(-)
>
> diff --git a/tools/testing/selftests/kselftest_deps.sh b/tools/testing/selftests/kselftest_deps.sh
> index 487e49fdf2a6..70b834361cb7 100755
> --- a/tools/testing/selftests/kselftest_deps.sh
> +++ b/tools/testing/selftests/kselftest_deps.sh
> @@ -10,13 +10,20 @@
>  usage()
>  {
>
> -echo -e "Usage: $0 -[p] <compiler> [test_name]\n"
> +echo -e "Usage: $0 -[p] <compiler> [ARCH=<arch>] [test_name]\n"
>  echo -e "\tkselftest_deps.sh [-p] gcc"
>  echo -e "\tkselftest_deps.sh [-p] gcc mm"
>  echo -e "\tkselftest_deps.sh [-p] aarch64-linux-gnu-gcc"
> -echo -e "\tkselftest_deps.sh [-p] aarch64-linux-gnu-gcc mm\n"
> +echo -e "\tkselftest_deps.sh [-p] aarch64-linux-gnu-gcc mm"
> +echo -e "\tkselftest_deps.sh [-p] LLVM"
> +echo -e "\tkselftest_deps.sh [-p] LLVM ARCH=arm64 mm\n"
>  echo "- Should be run in selftests directory in the kernel repo."
>  echo "- Checks if Kselftests can be built/cross-built on a system."
> +echo "- Compiler can be given as LLVM to use clang, as with LLVM=1 in"
> +echo "  the kselftest build. LLVM=<prefix>/ and LLVM=-<suffix> select"
> +echo "  the clang binary as in the kselftest build. ARCH=<arch> selects"
> +echo "  the clang target architecture, defaulting to the host; it is"
> +echo "  ignored for other compilers."
>  echo "- Parses all test/sub-test Makefile to find library dependencies."
>  echo "- Runs compile test on a trivial C file with LDLIBS specified"
>  echo "  in the test Makefiles to identify missing library dependencies."
> @@ -53,13 +60,32 @@ while getopts "p" arg; do
>         esac
>  done
>
> +# Pull an optional ARCH=<arch> out of the remaining arguments. The
> +# environment is used if it is not given on the command line, as with
> +# make.
> +args=()
> +for arg in "$@"; do
> +       case "$arg" in
> +               ARCH=*)
> +               ARCH=${arg#ARCH=};;
> +               *)
> +               args+=("$arg");;
> +       esac
> +done
> +set -- "${args[@]}"
> +
>  if [ $# -eq 0 ]
>  then
>         usage
>  fi
>
>  # Compiler
> -CC=$1
> +case "$1" in
> +       LLVM|LLVM=*)
> +       setup_llvm "${1#LLVM}";;
> +       *)
> +       CC=$1;;
> +esac
>
>  tmp_file=$(mktemp).c
>  trap "rm -f $tmp_file.o $tmp_file $tmp_file.bin" EXIT
> @@ -178,6 +204,56 @@ exit $?
>  }
>  # end main()
>
> +# Mirror the LLVM handling in lib.mk: LLVM=<prefix>/ or LLVM=-<suffix>
> +# select the clang binary, and ARCH selects the target triple with the
> +# host as the default.
> +setup_llvm()
> +{
> +       local llvm=${1#=}
> +       local llvm_prefix=""
> +       local llvm_suffix=""
> +       local clang
> +       local target
> +
> +       declare -A clang_target
> +       clang_target[arm]=arm-linux-gnueabi
> +       clang_target[arm64]=aarch64-linux-gnu
> +       clang_target[hexagon]=hexagon-linux-musl
> +       clang_target[i386]=i386-linux-gnu
> +       clang_target[m68k]=m68k-linux-gnu
> +       clang_target[mips]=mipsel-linux-gnu
> +       clang_target[powerpc]=powerpc64le-linux-gnu
> +       clang_target[riscv]=riscv64-linux-gnu
> +       clang_target[s390]=s390x-linux-gnu
> +       clang_target[x86]=x86_64-linux-gnu

^ should this be either i386-linux-gnu or i686-linux-gnu, or does
`-m32` get set somewhere?

> +       clang_target[x86_64]=x86_64-linux-gnu
> +
> +       case "$llvm" in
> +               */)
> +               llvm_prefix=$llvm;;
> +               -*)
> +               llvm_suffix=$llvm;;
> +       esac
> +       clang=${llvm_prefix}clang${llvm_suffix}
> +
> +       if [ -z "$ARCH" ]; then
> +               target=$($clang -print-target-triple 2>/dev/null)
> +               if [ -z "$target" ]; then
> +                       echo -e "\tUnable to run $clang ..."
> +                       exit 1
> +               fi
> +       else
> +               target=${clang_target[$ARCH]}
> +               if [ -z "$target" ]; then
> +                       echo -e "\tUnknown ARCH $ARCH for LLVM, supported:"
> +                       echo -e "\t$(echo "${!clang_target[*]}" | xargs -n1 | sort | xargs)"
> +                       exit 1
> +               fi
> +       fi
> +
> +       CC="$clang --target=$target -fintegrated-as"
> +}
> +
>  all_tests()
>  {
>         for test in $l1_tests; do
> @@ -285,6 +361,7 @@ print_results()
>  {
>         echo -e "========================================================";
>         echo -e "Kselftest Dependency Check for [$0 $1 $2] results..."
> +       echo -e "Compiler: $CC"
>
>         if [ $print_targets -ne 0 ]
>         then
>
> ---
> base-commit: 24a19b953e2a3d0ea5a8c4951a0ab8f32720c907
> base-tree: git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm master
> change-id: 20261013-kselftest-deps-llvm-51be8d160008
>
> Best regards,
> --
> Mark Brown <broonie@kernel.org>
>


-- 
Thanks,
~Nick Desaulniers

Re: [PATCH] selftests: kselftest_deps.sh: Support LLVM

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 597 bytes --]

On Tue, Oct 13, 2026 at 02:07:28PM -0700, Nick Desaulniers wrote:
> On Tue, Oct 13, 2026 at 12:40 PM Mark Brown <broonie@kernel.org> wrote:

> > +       clang_target[riscv]=riscv64-linux-gnu
> > +       clang_target[s390]=s390x-linux-gnu
> > +       clang_target[x86]=x86_64-linux-gnu

> ^ should this be either i386-linux-gnu or i686-linux-gnu, or does
> `-m32` get set somewhere?

Hrm, that'll just be a cut'n'paste from lib.mk which does not so far as
I can see set -m32 - it sets i386-linux-gnu for _i386.  Does that need a
fix too, or am I missing something with how it works?

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]