steps:

- bash: |
    set -e
    curl -f http://releases.llvm.org/7.0.0/clang+llvm-7.0.0-x86_64-apple-darwin.tar.xz | tar xJf -

    export CC=`pwd`/clang+llvm-7.0.0-x86_64-apple-darwin/bin/clang
    echo "##vso[task.setvariable variable=CC]$CC"

    export CXX=`pwd`/clang+llvm-7.0.0-x86_64-apple-darwin/bin/clang++
    echo "##vso[task.setvariable variable=CXX]$CXX"

    # Configure `AR` specifically so rustbuild doesn't try to infer it as
    # `clang-ar` by accident.
    echo "##vso[task.setvariable variable=AR]ar"
  displayName: Install clang (OSX)
  condition: and(succeeded(), eq(variables['Agent.OS'], 'Darwin'))

# 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!
#
# Note that the LLVM installer is an NSIS installer
#
# Original downloaded here came from
# http://releases.llvm.org/7.0.0/LLVM-7.0.0-win64.exe
- script: |
    powershell -Command "iwr -outf %TEMP%\LLVM-7.0.0-win64.exe https://rust-lang-ci2.s3.amazonaws.com/rust-ci-mirror/LLVM-7.0.0-win64.exe"
    set CLANG_DIR=%CD%\citools\clang-rust
    %TEMP%\LLVM-7.0.0-win64.exe /S /NCRC /D=%CLANG_DIR%
    set RUST_CONFIGURE_ARGS=%RUST_CONFIGURE_ARGS% --set llvm.clang-cl=%CLANG_DIR%\bin\clang-cl.exe
    echo ##vso[task.setvariable variable=RUST_CONFIGURE_ARGS]%RUST_CONFIGURE_ARGS%
  condition: and(succeeded(), eq(variables['Agent.OS'], 'Windows_NT'), eq(variables['MINGW_URL'],''))
  displayName: Install clang (Windows)

# 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.