install_llvm

#!/usr/bin/env bash

set -uo pipefail

# File: Setup LLVM/Clang Toolchain
# See: https://apt.llvm.org/

LLVM_VERSION=17
LLVM_VERSIONS=("${LLVM_VERSION}")

function install_llvm()
{
	local codename
	codename=$(grep "DISTRIB_CODENAME" /etc/lsb-release)
	codename=${CODENAME:17}

	# retrieve the archive signature
	wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key|sudo apt-key add -

	local apt_file="/etc/apt/sources.list.d/llvm-toolchain-${codename}.list"
	sudo rm -f "${apt_file}"
	echo "deb http://apt.llvm.org/${codename}/ llvm-toolchain-${codename}-${LLVM_VERSION} main
deb-src http://apt.llvm.org/${codename}/ llvm-toolchain-${codename}-${LLVM_VERSION} main" | \
		sudo tee "${apt_file}"
	sudo apt update -q=2

	sudo apt install \
		 "clang-${LLVM_VERSION}" \
		 "clang-${LLVM_VERSION}-doc" \
		 "clang-${LLVM_VERSION}-examples" \
		 "clang-format-${LLVM_VERSION}" \
		 "clang-tools-${LLVM_VERSION}" \
		 "clangd-${LLVM_VERSION}" \
		 "llvm-${LLVM_VERSION}-dev" \
		 "llvm-${LLVM_VERSION}-tools" \
		 "llvm-${LLVM_VERSION}-linker-tools" \
		 "lld-${LLVM_VERSION}"

	# make recent clang default
	sudo ln -sf "/usr/lib/llvm-${LLVM_VERSION}/bin/clang" /usr/bin/clang
	sudo ln -sf "/usr/lib/llvm-${LLVM_VERSION}/bin/clang++" /usr/bin/clang++
	sudo ln -sf "/usr/bin/lld-${LLVM_VERSION}" /usr/bin/lld
}

function assert_llvm()
{
	CLANG="/usr/lib/llvm-${LLVM_VERSION}/bin/clang"
	if [ ! -e "${CLANG}" ]; then
		echo "Installing Clang and LLVM version ${LLVM_VERSION} ..."
		install_llvm
	fi
}

for LLVM_VERSION in "${LLVM_VERSIONS[@]}"; do
	assert_llvm
done