install-clang.sh

#!/bin/bash
# ignore-tidy-linelength
# This script installs clang on the local machine. Note that we don't install
# clang on Linux since its compiler story is just so different. Each container
# has its own toolchain configured appropriately already.

set -euo pipefail
IFS=$'\n\t'

source "$(cd "$(dirname "$0")" && pwd)/../shared.sh"

# Update both macOS's and Windows's tarballs when bumping the version here.
# Try to keep this in sync with src/ci/docker/host-x86_64/dist-x86_64-linux/build-clang.sh
LLVM_VERSION="18.1.4"

if isMacOS; then
    # FIXME: This is the latest pre-built version of LLVM that's available for
    # x86_64 MacOS. We may want to consider bulding our own LLVM binaries
    # instead, or set `USE_XCODE_CLANG` like AArch64 does.
    LLVM_VERSION="15.0.7"

    # If the job selects a specific Xcode version, use that instead of
    # downloading our own version.
    if [[ ${USE_XCODE_CLANG-0} -eq 1 ]]; then
        bindir="$(xcode-select --print-path)/Toolchains/XcodeDefault.xctoolchain/usr/bin"
    else
        file="${MIRRORS_BASE}/clang%2Bllvm-${LLVM_VERSION}-x86_64-apple-darwin21.0.tar.xz"
        retry curl -f "${file}" -o "clang+llvm-${LLVM_VERSION}-x86_64-apple-darwin21.0.tar.xz"
        tar xJf "clang+llvm-${LLVM_VERSION}-x86_64-apple-darwin21.0.tar.xz"
        bindir="$(pwd)/clang+llvm-${LLVM_VERSION}-x86_64-apple-darwin21.0/bin"
    fi

    ciCommandSetEnv CC "${bindir}/clang"
    ciCommandSetEnv CXX "${bindir}/clang++"

    # macOS 10.15 onwards doesn't have libraries in /usr/include anymore: those
    # are now located deep into the filesystem, under Xcode's own files. The
    # native clang is configured to use the correct path, but our custom one
    # doesn't. This sets the SDKROOT environment variable to the SDK so that
    # our own clang can figure out the correct include path on its own.
    ciCommandSetEnv SDKROOT "$(xcrun --sdk macosx --show-sdk-path)"

    # Configure `AR` specifically so bootstrap doesn't try to infer it as
    # `clang-ar` by accident.
    ciCommandSetEnv AR "ar"
elif isWindows && ! isKnownToBeMingwBuild; then
    # If we're compiling for MSVC then we, like most other distribution builders,
    # switch to clang as the compiler. This'll allow us eventually to enable LTO
    # amongst LLVM and rustc. Note that we only do this on MSVC as I don't think
    # clang has an output mode compatible with MinGW that we need. If it does we
    # should switch to clang for MinGW as well!
    #
    # The LLVM installer is an NSIS installer, which we can extract with 7z. We
    # don't want to run the installer directly; extracting it is more reliable
    # in CI environments.

    mkdir -p citools/clang-rust
    cd citools
    retry curl -f "${MIRRORS_BASE}/LLVM-${LLVM_VERSION}-win64.exe" \
        -o "LLVM-${LLVM_VERSION}-win64.exe"
    7z x -oclang-rust/ "LLVM-${LLVM_VERSION}-win64.exe"
    ciCommandSetEnv RUST_CONFIGURE_ARGS \
        "${RUST_CONFIGURE_ARGS} --set llvm.clang-cl=$(pwd)/clang-rust/bin/clang-cl.exe"

    # Disable downloading CI LLVM on this builder;
    # setting up clang-cl just above conflicts with the default if-unchanged option.
    ciCommandSetEnv NO_DOWNLOAD_CI_LLVM 1
fi

if isWindows; then
    # GitHub image 20210928.2 added LLVM, but it is broken (and we don't want
    # to use it anyways).
    rm -rf /c/Program\ Files/LLVM
fi