Added Dockerfiles to build clang from sources.

Reviewers: klimek, chandlerc, mehdi_amini

Reviewed By: klimek, mehdi_amini

Subscribers: mehdi_amini, jlebar, llvm-commits

Differential Revision: https://reviews.llvm.org/D34197

llvm-svn: 306810

11 files changed, 654 insertions, 0 deletions

diff --git a/llvm/docs/Docker.rst b/llvm/docs/Docker.rst
new file mode 100644
index 00000000000..d873e1ebeeb
--- /dev/null
+++ b/llvm/docs/Docker.rst
@@ -0,0 +1,205 @@
+=========================================
+A guide to Dockerfiles for building LLVM
+=========================================
+
+Introduction
+============
+You can find a number of sources to build docker images with LLVM components in
+``llvm/utils/docker``. They can be used by anyone who wants to build the docker
+images for their own use, or as a starting point for someone who wants to write
+their own Dockerfiles.
+
+We currently provide Dockerfiles with ``debian8`` and ``nvidia-cuda`` base images.
+We also provide an ``example`` image, which contains placeholders that one would need
+to fill out in order to produce Dockerfiles for a new docker image.
+
+Why?
+----
+Docker images provide a way to produce binary distributions of
+software inside a controlled environment. Having Dockerfiles to builds docker images
+inside LLVM repo makes them much more discoverable than putting them into any other
+place.
+
+Docker basics
+-------------
+If you've never heard about Docker before, you might find this section helpful
+to get a very basic explanation of it.
+`Docker <https://www.docker.com/>`_ is a popular solution for running programs in
+an isolated and reproducible environment, especially to maintain releases for
+software deployed to large distributed fleets.
+It uses linux kernel namespaces and cgroups to provide a lightweight isolation
+inside currently running linux kernel.
+A single active instance of dockerized environment is called a *docker
+container*.
+A snapshot of a docker container filesystem is called a *docker image*.
+One can start a container from a prebuilt docker image.
+
+Docker images are built from a so-called *Dockerfile*, a source file written in
+a specialized language that defines instructions to be used when build
+the docker image (see `official
+documentation <https://docs.docker.com/engine/reference/builder/>`_ for more
+details). A minimal Dockerfile typically contains a base image and a number
+of RUN commands that have to be executed to build the image. When building a new
+image, docker will first download your base image, mount its filesystem as
+read-only and then add a writable overlay on top of it to keep track of all
+filesystem modifications, performed while building your image. When the build
+process is finished, a diff between your image's final filesystem state and the
+base image's filesystem is stored in the resulting image.
+
+Overview
+========
+The ``llvm/utils/docker`` folder contains Dockerfiles and simple bash scripts to
+serve as a basis for anyone who wants to create their own Docker image with
+LLVM components, compiled from sources. The sources are checked out from the
+upstream svn repository when building the image.
+
+Inside each subfolder we host Dockerfiles for two images:
+
+- ``build/`` image is used to compile LLVM, it installs a system compiler and all
+  build dependencies of LLVM. After the build process is finished, the build
+  image will have an archive with compiled components at ``/tmp/clang.tar.gz``.
+- ``release/`` image usually only contains LLVM components, compiled by the
+  ``build/`` image, and also libstdc++ and binutils to make image minimally
+  useful for C++ development. The assumption is that you usually want clang to
+  be one of the provided components.
+
+To build both of those images, use ``build_docker_image.sh`` script.
+It will checkout LLVM sources and build clang in the ``build`` container, copy results
+of the build to the local filesystem and then build the ``release`` container using
+those. The ``build_docker_image.sh`` accepts a list of LLVM repositories to
+checkout, and arguments for CMake invocation.
+
+If you want to write your own docker image, start with an ``example/`` subfolder.
+It provides incomplete Dockerfiles with (very few) FIXMEs explaining the steps
+you need to take in order to make your Dockerfiles functional.
+
+Usage
+=====
+The ``llvm/utils/build_docker_image.sh`` script provides a rather high degree of
+control on how to run the build. It allows you to specify the projects to
+checkout from svn and provide a list of CMake arguments to use during when
+building LLVM inside docker container.
+
+Here's a very simple example of getting a docker image with clang binary,
+compiled by the system compiler in the debian8 image:
+
+.. code-block:: bash
+
+    ./llvm/utils/docker/build_docker_image.sh \
+	--source debian8 \
+	--docker-repository clang-debian8 --docker-tag "staging" \
+	-- \
+	-p clang -i install-clang -i install-clang-headers \
+	-- \
+	-DCMAKE_BUILD_TYPE=Release
+
+Note there are two levels of ``--`` indirection. First one separates
+``build_docker_image.sh`` arguments from ``llvm/utils/build_install_llvm.sh``
+arguments. Second one separates CMake arguments from ``build_install_llvm.sh``
+arguments. Note that build like that doesn't use a 2-stage build process that
+you probably want for clang. Running a 2-stage build is a little more intricate,
+this command will do that:
+
+.. code-block:: bash
+
+    # Run a 2-stage build.
+    #   LLVM_TARGETS_TO_BUILD=Native is to reduce stage1 compile time.
+    #   Options, starting with BOOTSTRAP_* are passed to stage2 cmake invocation.
+    ./build_docker_image.sh \
+	--source debian8 \
+	--docker-repository clang-debian8 --docker-tag "staging" \
+	-- \
+	-p clang -i stage2-install-clang -i stage2-install-clang-headers \
+	-- \
+	-DLLVM_TARGETS_TO_BUILD=Native -DCMAKE_BUILD_TYPE=Release \
+	-DBOOTSTRAP_CMAKE_BUILD_TYPE=Release \
+	-DCLANG_ENABLE_BOOTSTRAP=ON -DCLANG_BOOTSTRAP_TARGETS="install-clang;install-clang-headers"
+	
+This will produce two images, a release image ``clang-debian8:staging`` and a
+build image ``clang-debian8-build:staging`` from the latest upstream revision.
+After the image is built you can run bash inside a container based on your
+image like this:
+
+.. code-block:: bash
+
+    docker run -ti clang-debian8:staging bash
+
+Now you can run bash commands as you normally would:
+
+.. code-block:: bash
+
+    root@80f351b51825:/# clang -v
+    clang version 5.0.0 (trunk 305064)
+    Target: x86_64-unknown-linux-gnu
+    Thread model: posix
+    InstalledDir: /bin
+    Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
+    Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.4
+    Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
+    Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.2
+    Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
+    Candidate multilib: .;@m64
+    Selected multilib: .;@m64
+
+
+Which image should I choose?
+============================
+We currently provide two images: debian8-based and nvidia-cuda-based. They
+differ in the base image that they use, i.e. they have a different set of
+preinstalled binaries. Debian8 is very minimal, nvidia-cuda is larger, but has
+preinstalled CUDA libraries and allows to access a GPU, installed on your
+machine.
+
+If you need a minimal linux distribution with only clang and libstdc++ included,
+you should try debian8-based image.
+
+If you want to use CUDA libraries and have access to a GPU on your machine,
+you should choose nvidia-cuda-based image and use `nvidia-docker
+<https://github.com/NVIDIA/nvidia-docker>`_ to run your docker containers. Note
+that you don't need nvidia-docker to build the images, but you need it in order
+to have an access to GPU from a docker container that is running the built
+image.
+
+If you have a different use-case, you could create your own image based on
+``example/`` folder.
+
+Any docker image can be built and run using only the docker binary, i.e. you can
+run debian8 build on Fedora or any other Linux distribution. You don't need to
+install CMake, compilers or any other clang dependencies. It is all handled
+during the build process inside Docker's isolated environment.
+
+Stable build
+============
+If you want a somewhat recent and somewhat stable build, use the
+``branches/google/stable`` branch, i.e. the following command will produce a
+debian8-based image using the latest ``google/stable`` sources for you:
+
+.. code-block:: bash
+
+    ./llvm/utils/docker/build_docker_image.sh \
+	-s debian8 --d clang-debian8 -t "staging" \
+	-- \
+	--branch branches/google/stable \
+	-p clang -i install-clang -i install-clang-headers \
+	-- \
+	-DCMAKE_BUILD_TYPE=Release
+
+
+Minimizing docker image size
+============================
+Due to Docker restrictions we use two images (i.e., build and release folders)
+for the release image to be as small as possible. It's much easier to achieve
+that using two images, because Docker would store a filesystem layer for each
+command in the  Dockerfile, i.e. if you install some packages in one command,
+then remove  those in a separate command, the size of the resulting image will
+still be proportinal to the size of an image with installed packages.
+Therefore, we strive to provide a very simple release image which only copies
+compiled clang and does not do anything else.
+
+Docker 1.13 added a ``--squash`` flag that allows to flatten the layers of the
+image, i.e. remove the parts that were actually deleted. That is an easier way
+to produce the smallest images possible by using just a single image. We do not
+use it because as of today the flag is in experimental stage and not everyone
+may have the latest docker version available. When the flag is out of
+experimental stage, we should investigate replacing two images approach with
+just a single image, built using ``--squash`` flag.
diff --git a/llvm/docs/index.rst b/llvm/docs/index.rst
index 54b60823653..7f3788f95b6 100644
--- a/llvm/docs/index.rst
+++ b/llvm/docs/index.rst
@@ -91,6 +91,7 @@ representation.
    CompileCudaWithLLVM
    ReportingGuide
    Benchmarking
+   Docker
 
 :doc:`GettingStarted`
    Discusses how to get up and running quickly with the LLVM infrastructure.
@@ -161,6 +162,9 @@ representation.
    A collection of tips for frontend authors on how to generate IR 
    which LLVM is able to effectively optimize.
 
+:doc:`Docker`
+   A reference for using Dockerfiles provided with LLVM.
+
 
 Programming Documentation
 =========================
diff --git a/llvm/utils/docker/README b/llvm/utils/docker/README
new file mode 100644
index 00000000000..be08dfa4c50
--- /dev/null
+++ b/llvm/utils/docker/README
@@ -0,0 +1 @@
+See llvm/docs/Docker.rst for details
diff --git a/llvm/utils/docker/build_docker_image.sh b/llvm/utils/docker/build_docker_image.sh
new file mode 100755
index 00000000000..2ec07ab6da4
--- /dev/null
+++ b/llvm/utils/docker/build_docker_image.sh
@@ -0,0 +1,121 @@
+#!/bin/bash
+#===- llvm/utils/docker/build_docker_image.sh ----------------------------===//
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===----------------------------------------------------------------------===//
+set -e
+
+IMAGE_SOURCE=""
+DOCKER_REPOSITORY=""
+DOCKER_TAG=""
+BUILDSCRIPT_ARGS=""
+
+function show_usage() {
+  usage=$(cat << EOF
+Usage: build_docker_image.sh [options] [-- [buildscript_args]...]
+
+Available options:
+    -s|--source             image source dir (i.e. debian8, nvidia-cuda, etc)
+    -d|--docker-repository  docker repository for the image
+    -t|--docker-tag         docker tag for the image
+Required options: --source and --docker-repository.
+
+All options after '--' are passed to buildscript (see
+scripts/build_install_llvm.sh).
+
+For example, running:
+$ build_docker_image.sh -s debian8 -d mydocker/debian8-clang -t latest \ 
+  -- -p clang -i install-clang -i install-clang-headers
+will produce two docker images:
+    mydocker/debian8-clang-build:latest - an intermediate image used to compile
+      clang.
+    mydocker/clang-debian8:latest       - a small image with preinstalled clang.
+Please note that this example produces a not very useful installation, since it
+doesn't override CMake defaults, which produces a Debug and non-boostrapped
+version of clang.
+For an example of a somewhat more useful build, see build_clang_image.sh.
+EOF
+)
+  echo "$usage"
+}
+
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    -h|--help)
+      show_usage
+      exit 0
+      ;;
+    -s|--source)
+      shift
+      IMAGE_SOURCE="$1"
+      shift
+      ;;
+    -d|--docker-repository)
+      shift
+      DOCKER_REPOSITORY="$1"
+      shift
+      ;;
+    -t|--docker-tag)
+      shift
+      DOCKER_TAG="$1"
+      shift
+      ;;
+    --)
+      shift
+      BUILDSCRIPT_ARGS="$*"
+      shift $#
+      ;;
+    *)
+      echo "Unknown argument $1"
+      exit 1
+      ;;
+  esac
+done
+
+command -v docker >/dev/null ||
+  {
+    echo "Docker binary cannot be found. Please install Docker to use this script."
+    exit 1
+  }
+
+if [ "$IMAGE_SOURCE" == "" ]; then
+  echo "Required argument missing: --source"
+  exit 1
+fi
+
+if [ "$DOCKER_REPOSITORY" == "" ]; then
+  echo "Required argument missing: --docker-repository"
+  exit 1
+fi
+
+cd $(dirname $0)
+if [ ! -d $IMAGE_SOURCE ]; then
+  echo "No sources for '$IMAGE_SOURCE' were found in $PWD"
+  exit 1
+fi
+
+echo "Building from $IMAGE_SOURCE"
+
+if [ "$DOCKER_TAG" != "" ]; then
+  DOCKER_TAG=":$DOCKER_TAG"
+fi
+
+echo "Building $DOCKER_REPOSITORY-build$DOCKER_TAG"
+docker build -t "$DOCKER_REPOSITORY-build$DOCKER_TAG" \
+  --build-arg "buildscript_args=$BUILDSCRIPT_ARGS" \
+  -f "$IMAGE_SOURCE/build/Dockerfile" .
+
+echo "Copying clang installation to release image sources"
+docker run -v "$PWD/$IMAGE_SOURCE:/workspace" "$DOCKER_REPOSITORY-build$DOCKER_TAG" \
+  cp /tmp/clang.tar.gz /workspace/release
+trap "rm -f $PWD/$IMAGE_SOURCE/release/clang.tar.gz" EXIT
+
+echo "Building release image"
+docker build -t "${DOCKER_REPOSITORY}${DOCKER_TAG}" \
+  "$IMAGE_SOURCE/release"
+
+echo "Done"
diff --git a/llvm/utils/docker/debian8/build/Dockerfile b/llvm/utils/docker/debian8/build/Dockerfile
new file mode 100644
index 00000000000..13a11a73be6
--- /dev/null
+++ b/llvm/utils/docker/debian8/build/Dockerfile
@@ -0,0 +1,35 @@
+#===- llvm/utils/docker/debian8/build/Dockerfile -------------------------===//
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===----------------------------------------------------------------------===//
+# Produces an image that compiles and archives clang, based on debian8.
+FROM launcher.gcr.io/google/debian8:latest
+
+LABEL maintainer "LLVM Developers"
+
+# Install build dependencies of llvm.
+# First, Update the apt's source list and include the sources of the packages.
+RUN grep deb /etc/apt/sources.list | \
+    sed 's/^deb/deb-src /g' >> /etc/apt/sources.list
+
+# Install compiler, python and subversion.
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends build-essential python2.7 wget \
+            subversion ninja-build && \
+    rm -rf /var/lib/apt/lists/*
+
+# Install cmake version that can compile clang into /usr/local.
+# (Version in debian8 repos is is too old)
+RUN wget -O - "https://cmake.org/files/v3.7/cmake-3.7.2-Linux-x86_64.tar.gz" | \
+    tar xzf - -C /usr/local --strip-components=1
+
+# Arguments passed to build_install_clang.sh.
+ARG buildscript_args
+
+# Run the build. Results of the build will be available as /tmp/clang.tar.gz.
+ADD scripts/build_install_llvm.sh /tmp
+RUN /tmp/build_install_llvm.sh ${buildscript_args}
diff --git a/llvm/utils/docker/debian8/release/Dockerfile b/llvm/utils/docker/debian8/release/Dockerfile
new file mode 100644
index 00000000000..d0214b9c67a
--- /dev/null
+++ b/llvm/utils/docker/debian8/release/Dockerfile
@@ -0,0 +1,21 @@
+#===- llvm/utils/docker/debian8/release/Dockerfile -----------------------===//
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===----------------------------------------------------------------------===//
+# A release image, containing clang installation, produced by the 'build/' image
+# and adding libstdc++ and binutils.
+FROM launcher.gcr.io/google/debian8:latest
+
+LABEL maintainer "LLVM Developers"
+
+# Install packages for minimal usefull image.
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends libstdc++-4.9-dev binutils && \
+    rm -rf /var/lib/apt/lists/*
+
+# Unpack clang installation into this image.
+ADD clang.tar.gz /
diff --git a/llvm/utils/docker/example/build/Dockerfile b/llvm/utils/docker/example/build/Dockerfile
new file mode 100644
index 00000000000..597ccfeb4f2
--- /dev/null
+++ b/llvm/utils/docker/example/build/Dockerfile
@@ -0,0 +1,26 @@
+#===- llvm/utils/docker/example/build/Dockerfile -------------------------===//
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===----------------------------------------------------------------------===//
+# This is an example Dockerfile to build an image that compiles clang.
+# Replace FIXMEs to prepare your own image.
+
+# FIXME: Replace 'ubuntu' with your base image
+FROM ubuntu
+
+# FIXME: Change maintainer name
+LABEL maintainer "Maintainer <maintainer@email>"
+
+# FIXME: Install llvm/clang build dependencies. Including compiler to
+# build stage1, cmake, subversion, ninja, etc.
+
+# Arguments to pass to build_install_clang.sh.
+ARG buildscript_args
+
+# Run the build. Results of the build will be available as /tmp/clang.tar.gz.
+ADD scripts/build_install_llvm.sh /tmp
+RUN /tmp/build_install_llvm.sh ${buildscript_args}
diff --git a/llvm/utils/docker/example/release/Dockerfile b/llvm/utils/docker/example/release/Dockerfile
new file mode 100644
index 00000000000..953d81fc995
--- /dev/null
+++ b/llvm/utils/docker/example/release/Dockerfile
@@ -0,0 +1,24 @@
+#===- llvm/utils/docker/example/release/Dockerfile -----------------------===//
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===----------------------------------------------------------------------===//
+# An image that unpacks a clang installation, compiled by the 'build/'
+# container.
+# Replace FIXMEs to prepare your own image.
+
+# FIXME: Replace 'ubuntu' with your base image.
+FROM ubuntu
+
+# FIXME: Change maintainer name.
+LABEL maintainer "Maintainer <maintainer@email>"
+
+# FIXME: Install all packages you want to have in your release container.
+# A minimal usefull installation must include libstdc++ and binutils.
+
+# Unpack clang installation into this container.
+# It is copied to this directory by build_docker_image.sh script.
+ADD clang.tar.gz /
diff --git a/llvm/utils/docker/nvidia-cuda/build/Dockerfile b/llvm/utils/docker/nvidia-cuda/build/Dockerfile
new file mode 100644
index 00000000000..619b80cbb61
--- /dev/null
+++ b/llvm/utils/docker/nvidia-cuda/build/Dockerfile
@@ -0,0 +1,25 @@
+#===- llvm/utils/docker/nvidia-cuda/build/Dockerfile ---------------------===//
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===----------------------------------------------------------------------===//
+# Produces an image that compiles and archives clang, based on nvidia/cuda
+# image.
+FROM nvidia/cuda:8.0-devel
+
+LABEL maintainer "LLVM Developers"
+
+# Arguments to pass to build_install_clang.sh.
+ARG buildscript_args
+
+# Install llvm build dependencies.
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends cmake python2.7 subversion ninja-build && \
+    rm -rf /var/lib/apt/lists/*
+
+# Run the build. Results of the build will be available as /tmp/clang.tar.gz.
+ADD scripts/build_install_llvm.sh /tmp
+RUN /tmp/build_install_llvm.sh ${buildscript_args}
diff --git a/llvm/utils/docker/nvidia-cuda/release/Dockerfile b/llvm/utils/docker/nvidia-cuda/release/Dockerfile
new file mode 100644
index 00000000000..b9bcae15978
--- /dev/null
+++ b/llvm/utils/docker/nvidia-cuda/release/Dockerfile
@@ -0,0 +1,23 @@
+#===- llvm/utils/docker/nvidia-cuda/release/Dockerfile -------------------===//
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===----------------------------------------------------------------------===//
+# This is an example Dockerfile that copies a clang installation, compiled
+# by the 'build/' container into a fresh docker image to get a container of
+# minimal size.
+# Replace FIXMEs to prepare a new Dockerfile.
+
+# FIXME: Replace 'ubuntu' with your base image.
+FROM nvidia/cuda:8.0-devel
+
+# FIXME: Change maintainer name.
+LABEL maintainer "LLVM Developers"
+
+# Unpack clang installation into this container.
+ADD clang.tar.gz /
+
+# C++ standard library and binutils are already included in the base package.
diff --git a/llvm/utils/docker/scripts/build_install_llvm.sh b/llvm/utils/docker/scripts/build_install_llvm.sh
new file mode 100755
index 00000000000..7e0e9065741
--- /dev/null
+++ b/llvm/utils/docker/scripts/build_install_llvm.sh
@@ -0,0 +1,169 @@
+#!/usr/bin/env bash
+#===- llvm/utils/docker/scripts/build_install_llvm.sh ---------------------===//
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===-----------------------------------------------------------------------===//
+
+set -e
+
+function show_usage() {
+  usage=$(cat << EOF
+Usage: build_install_llvm.sh [options] -- [cmake-args]
+
+Checkout svn sources and run cmake with the specified arguments. Used
+inside docker container.
+Passes additional -DCMAKE_INSTALL_PREFIX and archives the contents of
+the directory to /tmp/clang.tar.gz.
+
+Available options:
+  -h|--help           show this help message
+  -b|--branch         svn branch to checkout, i.e. 'trunk',
+                      'branches/release_40'
+                      (default: 'trunk')
+  -r|--revision       svn revision to checkout
+  -p|--llvm-project   name of an svn project to checkout. Will also add the
+                      project to a list LLVM_ENABLE_PROJECTS, passed to CMake.
+                      For clang, please use 'clang', not 'cfe'.
+                      Project 'llvm' is always included and ignored, if
+                      specified.
+                      Can be specified multiple times.
+  -i|--install-target name of a cmake install target to build and include in
+                      the resulting archive. Can be specified multiple times.
+Required options: At least one --install-target.
+
+All options after '--' are passed to CMake invocation.
+EOF
+)
+  echo "$usage"
+}
+
+LLVM_SVN_REV=""
+LLVM_BRANCH=""
+CMAKE_ARGS=""
+CMAKE_INSTALL_TARGETS=""
+# We always checkout llvm
+LLVM_PROJECTS="llvm"
+CMAKE_LLVM_ENABLE_PROJECTS=""
+
+function contains_project() {
+  local TARGET_PROJ="$1"
+  local PROJ
+  for PROJ in $LLVM_PROJECTS; do
+    if [ "$PROJ" == "$TARGET_PROJ" ]; then
+      return 0
+    fi
+  done
+  return 1
+}
+
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    -r|--revision)
+      shift
+      LLVM_SVN_REV="$1"
+      ;;
+    -b|--branch)
+      shift
+      LLVM_BRANCH="$1"
+      shift
+      ;;
+    -p|--llvm-project)
+      shift
+      PROJ="$1"
+      if [ "$PROJ" == "cfe" ]; then
+        PROJ="clang"
+      fi
+      if ! contains_project "$PROJ" ; then
+        LLVM_PROJECTS="$LLVM_PROJECTS $PROJ"
+        CMAKE_LLVM_ENABLE_PROJECTS="$CMAKE_LLVM_ENABLED_PROJECTS;$PROJ"
+      else
+        echo "Project '$PROJ' is already enabled, ignoring extra occurences."
+      fi
+      shift
+      ;;
+    -i|--install-target)
+      shift
+      CMAKE_INSTALL_TARGETS="$CMAKE_INSTALL_TARGETS $1"
+      shift
+      ;;
+    --)
+      shift
+      CMAKE_ARGS="$*"
+      shift $#
+      ;;
+    -h|--help)
+      show_usage
+      exit 0
+      ;;
+    *)
+      echo "Unknown option: $1"
+      exit 1
+  esac
+done
+
+if [ "$CMAKE_INSTALL_TARGETS" == "" ]; then
+  echo "No install targets. Please pass one or more --install-target."
+  exit 1
+fi
+
+if [ "$LLVM_BRANCH" == "" ]; then
+  LLVM_BRANCH="trunk"
+fi
+
+if [ "$LLVM_SVN_REVISION" != "" ]; then
+  SVN_REV_ARG="-r$LLVM_SVN_REVISION"
+else
+  SVN_REV_ARG=""
+fi
+
+CLANG_BUILD_DIR=/tmp/clang-build
+CLANG_INSTALL_DIR=/tmp/clang-install
+
+mkdir "$CLANG_BUILD_DIR"
+
+# Get the sources from svn.
+echo "Checking out sources from svn"
+mkdir "$CLANG_BUILD_DIR/src"
+for LLVM_PROJECT in $LLVM_PROJECTS; do
+  if [ "$LLVM_PROJECT" == "clang" ]; then
+    SVN_PROJECT="cfe"
+  else
+    SVN_PROJECT="$LLVM_PROJECT"
+  fi
+
+  echo "Checking out http://llvm.org/svn/llvm-project/$SVN_PROJECT to $CLANG_BUILD_DIR/src/$LLVM_PROJECT"
+  # FIXME: --trust-server-cert is required to workaround 'SSL issuer is not
+  #        trusted' error. Using https seems preferable to http either way,
+  #        albeit this is not secure.
+  svn co -q $SVN_REV_ARG --trust-server-cert \
+    "https://llvm.org/svn/llvm-project/$SVN_PROJECT/$LLVM_BRANCH" \
+    "$CLANG_BUILD_DIR/src/$LLVM_PROJECT"
+done
+
+pushd "$CLANG_BUILD_DIR"
+
+# Run the build as specified in the build arguments.
+echo "Running build"
+mkdir "$CLANG_BUILD_DIR/build"
+cmake -GNinja \
+  -DCMAKE_INSTALL_PREFIX="$CLANG_INSTALL_DIR" \
+  -DLLVM_ENABLE_PROJECTS="$CMAKE_LLVM_ENABLE_PROJECTS" \
+  $CMAKE_ARGS \
+  "$CLANG_BUILD_DIR/src/llvm"
+ninja $CMAKE_INSTALL_TARGETS
+
+popd
+
+# Pack the installed clang into an archive.
+echo "Archiving clang installation to /tmp/clang.tar.gz"
+cd "$CLANG_INSTALL_DIR"
+tar -czf /tmp/clang.tar.gz *
+
+# Cleanup.
+rm -rf "$CLANG_BUILD_DIR" "$CLANG_INSTALL_DIR"
+
+echo "Done"