scripts: Add install-toolchain script

The script can be called in make target with in the docker image
creation to install the GCC/LLVM toolchain.

Change-Id: I58139c3b4d84fadee30e883846b7a924042b1578

install-toolchain.sh

diff --git a/install-toolchain.sh b/install-toolchain.sh
new file mode 100755
index 0000000..7997678
--- /dev/null
+++ b/install-toolchain.sh
@@ -0,0 +1,84 @@
+#!/bin/bash
+#
+# Copyright 2021 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Install the prebuilt RISC-V GCC/LLVM toolchain.
+
+function clean {
+  rm "${DOWNLOAD_DIR}/${TOOLCHAIN_TARBALL}" \
+     "${DOWNLOAD_DIR}/${TOOLCHAIN_TARBALL}.sha256sum"
+}
+
+function die {
+  echo "$@" >/dev/stderr
+  exit 1
+}
+
+function try {
+  $@ || die "Failed to execute '$@'"
+}
+
+if [[ -z "${ROOTDIR}" ]]; then
+  echo "Source build/setup.sh first"
+  exit 1
+fi
+if [[ -z "$1" ]]; then
+  cat << EOM
+Usage: install-toolchain.sh target
+Where target is gcc or llvm
+EOM
+  exit 1
+fi
+
+TARGET=${1:-gcc}
+TOOLCHAIN_TARBALL=""
+case "${TARGET}" in
+  gcc)
+    TOOLCHAIN_TARBALL="toolchain.tar.gz"
+    ;;
+
+  llvm)
+    TOOLCHAIN_TARBALL="toolchain_iree_rv32.tar.gz"
+    ;;
+
+  *)
+    echo "unsupported target: ${TARGET}"
+    exit 1
+    ;;
+esac
+
+DOWNLOAD_URL="https://storage.googleapis.com/shodan-public-artifacts/${TOOLCHAIN_TARBALL}"
+DOWNLOAD_DIR="${OUT}/tmp"
+
+trap clean EXIT
+
+wget -P "${DOWNLOAD_DIR}" "${DOWNLOAD_URL}"
+wget -P "${DOWNLOAD_DIR}" "${DOWNLOAD_URL}.sha256sum"
+pushd "${DOWNLOAD_DIR}" > /dev/null
+try sha256sum -c "${TOOLCHAIN_TARBALL}.sha256sum"
+popd > /dev/null
+
+try tar -C "${CACHE}" -xf "${DOWNLOAD_DIR}/${TOOLCHAIN_TARBALL}"
+
+# Prepare a newlib-nano directory for the default link of -lc, -lgloss, etc.
+# TODO(hcindyl): Remove the duped symlink creation once we switched to a toolchain from CI.
+if [[ "${TARGET}" == "llvm" ]]; then
+  lib_dir="${CACHE}/toolchain_iree_rv32imf/riscv32-unknown-elf/lib/"
+  try mkdir -p "${lib_dir}/newlib-nano"
+  try ln -rsf "${lib_dir}/libc_nano.a" "${lib_dir}/newlib-nano/libc.a"
+  try ln -rsf "${lib_dir}/libg_nano.a" "${lib_dir}/newlib-nano/libg.a"
+  try ln -rsf "${lib_dir}/libm_nano.a" "${lib_dir}/newlib-nano/libm.a"
+  try ln -rsf "${lib_dir}/libgloss_nano.a" "${lib_dir}/newlib-nano/libgloss.a"
+fi