Add llvm to PR ci

Author: patrick-rivos

.github/workflows/build.yaml

@@ -16,9 +16,14 @@ jobs:
         os:     [ubuntu-20.04, ubuntu-22.04]
         mode:   [newlib, linux, musl]
         target: [rv32gc-ilp32d, rv64gc-lp64d]
+        compiler: [gcc, llvm]
         exclude:
           - mode: musl
             target: rv32gc-ilp32d
+          - mode: newlib
+            compiler: llvm
+          - mode: musl
+            compiler: llvm
     steps:
       - uses: actions/checkout@v2
 
@@ -33,13 +38,19 @@ jobs:
       - name: build toolchain
         run: |
           TARGET_TUPLE=($(echo ${{ matrix.target }} | tr "-" "\n"))
-          ./configure --prefix=/opt/riscv --with-arch=${TARGET_TUPLE[0]} --with-abi=${TARGET_TUPLE[1]}
+          BUILD_TOOLCHAIN="./configure --prefix=/opt/riscv --with-arch=${TARGET_TUPLE[0]} --with-abi=${TARGET_TUPLE[1]}"
+          if [ "${{ matrix.compiler }}" == "llvm" ]; then # build toolchain with llvm
+            $BUILD_TOOLCHAIN --enable-llvm --enable-linux
+          else
+            $BUILD_TOOLCHAIN
+          fi
           sudo make -j $(nproc) ${{ matrix.mode }}
 
       - name: make report
         if: |
           matrix.os == 'ubuntu-20.04'
           && (matrix.mode == 'linux' || matrix.mode == 'newlib')
+          && matrix.compiler == 'gcc'
         run: |
           sudo make report-${{ matrix.mode }} -j $(nproc)
 
@@ -58,7 +69,7 @@ jobs:
             *)
               MODE="elf";;
           esac
-          echo ::set-output name=TOOLCHAIN_NAME::riscv$BITS-$MODE-${{ matrix.os }}-nightly
+          echo ::set-output name=TOOLCHAIN_NAME::riscv$BITS-$MODE-${{ matrix.os }}-${{ matrix.compiler }}-nightly
 
       - uses: actions/upload-artifact@v2
         with: