--- a/llvm.SlackBuild	2021-05-13 20:52:58.237323167 +0300
+++ b/llvm.SlackBuild	2021-05-20 19:35:01.902913345 +0300
@@ -39,10 +39,14 @@
   esac
 fi
 
+# Choose a compiler (gcc/g++ or clang/clang++):
+export CC=${CC:-clang}
+export CXX=${CXX:-clang++}
+
 # Building clangd will be determined automatically unless BUILD_CLANG is
 # preset to YES or NO:
 if [ -z $BUILD_CLANGD ]; then
-  if [ "$ARCH" = "i586" -o "$ARCH" = "i686" ]; then
+  if [ "$ARCH" = "i586" -o "$ARCH" = "i686" -o "$ARCH" = "riscv64" ]; then
     BUILD_CLANGD=NO
   else
     BUILD_CLANGD=YES
@@ -82,6 +86,12 @@
 elif [ "$ARCH" = "x86_64" ]; then
   SLKCFLAGS="-O2 -fPIC"
   LIBDIRSUFFIX="64"
+elif [ "$ARCH" = "aarch64" ]; then
+  SLKCFLAGS="-O2 -fPIC"
+  LIBDIRSUFFIX="64"
+elif [ "$ARCH" = "riscv64" ]; then
+  SLKCFLAGS="-O2 -fPIC"
+  LIBDIRSUFFIX="64"
 else
   SLKCFLAGS="-O2"
   LIBDIRSUFFIX=""
@@ -149,6 +159,12 @@
 # Hack to fix build with polly. Maybe we should just not use polly... ?
 zcat $CWD/llvm.polly.hack.diff.gz | patch -p1 --verbose || exit 1
 
+xzcat $CWD/clang.dynamic.linker.aarch64.patch.xz | patch -p1 --verbose || exit 1
+xzcat $CWD/clang.toolchains.aarch64.triple.patch.xz | patch -p1 --verbose || exit 1
+
+xzcat $CWD/clang.dynamic.linker.riscv64.patch.xz | patch -p1 --verbose || exit 1
+xzcat $CWD/clang.toolchains.riscv64.triple.patch.xz | patch -p1 --verbose || exit 1
+
 chown -R root:root .
 find . \
   \( -perm 777 -o -perm 775 -o -perm 750 -o -perm 711 -o -perm 555 -o -perm 511 \) \
@@ -156,6 +172,22 @@
   \( -perm 666 -o -perm 664 -o -perm 640 -o -perm 600 -o -perm 444 -o -perm 440 -o -perm 400 \) \
   -exec chmod 644 {} \+
 
+if [[ "$ARCH" == "riscv64" ]]; then
+    # when compiling gcc
+    # /usr/bin/ld: lib64/liblldbTarget.a(Process.cpp.o): in function `lldb_private::Process::Finalize()':
+    # Process.cpp:(.text._ZN12lldb_private7Process8FinalizeEv+0x2a): undefined reference to `__atomic_exchange_1'
+    [[ $CC == "gcc" ]] && export LDFLAGS="-latomic"
+
+    # /usr/bin/ld: lib64/liblldbPluginProcessLinux.a(NativeThreadLinux.cpp.o): in function `.LBB0_1':
+    # NativeThreadLinux.cpp:(.text._ZN12lldb_private13process_linux17NativeThreadLinuxC2ERNS0_18NativeProcessLinuxEm+0x46): undefined reference to `lldb_private::process_linux::NativeRegisterContextLinux::CreateHostNativeRegisterContextLinux(lldb_private::ArchSpec const&, lldb_private::NativeThreadProtocol&)'
+    OPTIONS="   -DLLDB_TOOL_LLDB_SERVER_BUILD=OFF \
+                -DLLVM_BUILD_EXAMPLES:BOOL=OFF \
+                -DLLVM_ENABLE_LIBCXX:BOOL=OFF \
+                -DLLVM_INSTALL_TOOLCHAIN_ONLY:BOOL=OFF"
+else
+    OPTIONS="-DLLVM_USE_LINKER=gold"
+fi
+
 mkdir build
 cd build
   mkdir include
@@ -164,15 +196,15 @@
   # Nuke LLVM libunwind as it conflicts with the one already on the system:
   rm -r ../projects/libunwind
   cmake -GNinja \
-    -DCMAKE_C_COMPILER="clang" \
-    -DCMAKE_CXX_COMPILER="clang++" \
+    -DCMAKE_C_COMPILER="$CC" \
+    -DCMAKE_CXX_COMPILER="$CXX" \
     -DCMAKE_C_FLAGS:STRING="$SLKCFLAGS" \
     -DCMAKE_CXX_FLAGS:STRING="$SLKCFLAGS" \
     -DCMAKE_INSTALL_PREFIX=/usr \
     -DLLVM_LIBDIR_SUFFIX=${LIBDIRSUFFIX} \
     -DCMAKE_BUILD_TYPE=Release \
     -DBUILD_SHARED_LIBS=ON \
-    -DLLVM_USE_LINKER=gold \
+    $OPTIONS \
     -DLLVM_ENABLE_RTTI=ON \
     -DLLVM_ENABLE_FFI=ON \
     -DLLVM_ENABLE_ASSERTIONS=OFF \