Add clang compile support

Backport commit 6ddb09145930b03c88e63f5930e718a33501024d Support CC=clang and LD=ld.lld & add clang llvm lld requires

Support-CC-clang-and-LD-ld.lld.patch

@@ -0,0 +1,59 @@
+From cfe6363124a0d0495727c6f4e8a1809b295a8cbf Mon Sep 17 00:00:00 2001
+From: liyunfei <liyunfei33@huawei.com>
+Date: Wed, 13 Sep 2023 10:05:33 +0800
+Subject: [PATCH] Support CC=clang and LD=ld.lld When building the Linux
+ kernel, one may use `make LLVM=1` to set multiple flags, akin to `make
+ CC=clang LD=ld.lld NM=llvm-nm ...` (see the link below for kernel docs
+ explaining this further in detail).
+
+When building kernel modules, to ensure we're using the same toolchain
+as the underlying core kernel image, Kbuild will error if it's reinvoked
+with a toolchain that differs. This causes DKMS to fail, since it's not
+re-specifying the same compiler (or linker, etc).
+
+Check the .comment section of the vmlinux file in the Linux kernel
+source dir, and set CC= and LD= flags for make based on that.
+
+If vmlinux does not exist, grep .config for CONFIG_CC_IS_CLANG=y and
+CONFIG_LD_IS_LLD=y.
+
+Fixes: #124
+Fixes: ClangBuiltLinux/linux#1104
+Link: https://docs.kernel.org/kbuild/llvm.html
+Suggested-by: Colin Ian King <colin.king@canonical.com>
+Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
+---
+ dkms | 17 +++++++++++++++++
+ 1 file changed, 17 insertions(+)
+
+diff --git a/dkms b/dkms
+index c4b9a26..983aefc 100755
+--- a/dkms
++++ b/dkms
+@@ -699,6 +699,23 @@ read_conf()
+         [[ ${MODULES_CONF[$index]} ]] && modules_conf_array[$index]="${MODULES_CONF[$index]}"
+     done
+ 
++    # Check if clang was used to compile or lld was used to link the kernel.
++    if [[ -e $kernel_source_dir/vmlinux ]]; then
++      if  readelf -p .comment $kernel_source_dir/vmlinux | grep -q clang; then
++        make_command="${make_command} CC=clang"
++      fi
++      if  readelf -p .comment $kernel_source_dir/vmlinux | grep -q LLD; then
++        make_command="${make_command} LD=ld.lld"
++      fi
++    elif [[ -e $kernel_source_dir/.config ]]; then
++      if grep -q CONFIG_CC_IS_CLANG=y $kernel_source_dir/.config; then
++        make_command="${make_command} CC=clang"
++      fi
++      if grep -q CONFIG_LD_IS_LLD=y $kernel_source_dir/.config; then
++        make_command="${make_command} LD=ld.lld"
++      fi
++    fi
++
+     # Set patch_array (including kernel specific patches)
+     count=0
+     for ((index=0; index < ${#PATCH[@]}; index++)); do
+-- 
+2.27.0
+

dkms.spec

@@ -1,19 +1,21 @@
 Summary: Dynamic Kernel Module Support Framework
 Name: dkms
 Version: 2.6.1
-Release: 7
+Release: 8
 License: GPLv2+
 BuildArch: noarch
 URL: https://github.com/dell/dkms
 Source0: https://github.com/dell/dkms/archive/v%{version}.tar.gz#/dkms-%{version}.tar.gz
 # because Mandriva calls this package dkms-minimal
 Patch0:   change-deprecated-egrep-for-grep-E.patch
+Patch1:   Support-CC-clang-and-LD-ld.lld.patch
 Provides: dkms-minimal = %{version}
 Requires: coreutils
 Requires: cpio
 Requires: findutils
 Requires: gawk
 Requires: gcc
+Requires: clang llvm lld
 Requires: grep
 Requires: gzip
 Requires: kernel-devel
@@ -128,6 +130,9 @@ fi
 %{_sysconfdir}/bash_completion.d/%{name}
 
 %changelog
+* Tue Sep 19 2023 liyunfei <liyunfei@huawei.com> - 2.6.1-8
+- Add clang compile support
+
 * Mon Mar 27 2023 wangkai <wangkai385@h-partners.com> - 2.6.1-7
 - Change deprecated egrep for grep -E