.. index:: LLVM
.. _LLVM:

LLVM
====

Description
-----------

The LLVM Project is a collection of modular and reusable compiler and toolchain technologies.  It includes compilers, debuggers, libraries and much more.

User instructions
-----------------

llvm (including the clang and clang++ compilers) is available via the modules system.  To add it to your environment run:

.. code-block:: bash

    $ module load llvm/4.0.1

Note that the llvm module includes the clang and clang++ compilers and the lldb debugger.

Source
------

www.llvm.org

License
-------

UIUC (BSD-style)

Admin notes
-----------

The complete build takes a while and including everything in the right place is a little complicated. So I wrote a script to do everything necessary based on the guide at http://clang.llvm.org. Note swig and libxml2-dev must be installed. Note also the build requires several tens of GB of space.

.. code-block:: bash

    #!/bin/bash

    llvm_release=4.0.1
    install_dir="/common/debian/9.1/Core/llvm/llvm-${llvm_release}"

    tools="cfe lld lldb polly clang-tools-extra"
    projects="compiler-rt libcxx libcxxabi libunwind openmp test-suite"
    packages="llvm ${tools} ${projects}"

    # Download source files
    for package in ${packages}; do
        if [ ! -f "${package}-${llvm_release}.src.tar.xz" ]; then
            wget http://releases.llvm.org/${llvm_release}/${package}-${llvm_release}.src.tar.xz
            if [ ! -f "${package}-${llvm_release}.src.tar.xz" ]; then
                echo Error downloading.
                exit 1
            fi

        fi
    done

    # unpack base
    tar -xf llvm-${llvm_release}.src.tar.xz

    # upack tools
    cd llvm-${llvm_release}.src/tools
    for tool in ${tools}; do
        tar --transform "s/-${llvm_release}.src//" -xf ../../${tool}-${llvm_release}.src.tar.xz
    done
    mv cfe clang
    mv clang-tools-extra clang/tools/extra

    # unpack projects
    cd ../projects
    for project in ${projects}; do
        tar --transform "s/-${llvm_release}.src//" -xf ../../${project}-${llvm_release}.src.tar.xz
    done

    # cmake in a build-dir
    cd ../../
    mkdir "build-${llvm_release}"
    cd "build-${llvm_release}"
    cmake -DCMAKE_INSTALL_PREFIX=${install_dir} ../llvm-${llvm_release}.src
    make
    make install