.. _build_toolchains:

===========================
Creating Toolchain Archives
===========================

There are various scripts in the repository for producing archives
of the build tools (e.g. compilers and linkers) required to build.

Clang
=====

See the ``build/build-clang`` directory. Read ``build/build-clang/README``
for more.

Windows
=======

The ``build/windows_toolchain.py`` script is used to build and manage
Windows toolchain archives containing Visual Studio executables, SDKs,
etc.

The way Firefox build automation works is an archive containing the
toolchain is produced and uploaded to an internal Mozilla server. The
build automation will download, verify, and extract this archive before
building. The archive is self-contained so machines don't need to install
Visual Studio, SDKs, or various other dependencies. Unfortunately,
Microsoft's terms don't allow Mozilla to distribute this archive
publicly. However, the same tool can be used to create your own copy.

Configuring Your System
-----------------------

It is **highly** recommended to perform this process on a fresh installation
of Windows 7 or 10 (such as in a VM). Installing all updates through
Windows Update is not only acceptable - it is encouraged. Although it
shouldn't matter.

Next, install Visual Studio 2017 Community. The download link can be found
at https://www.visualstudio.com/vs/community/.
Be sure to follow these install instructions:

1. Choose a ``Custom`` installation and click ``Next``
2. Select ``Programming Languages`` -> ``Visual C++`` (make sure all sub items are
   selected)
3. Under ``Windows and Web Development`` uncheck everything except
   ``Universal Windows App Development Tools`` and the items under it
   (should be ``Tools (1.3.1)...`` and the ``Windows 10 SDK``).

Once Visual Studio 2017 Community has been installed, from a checkout
of mozilla-central, run something like the following to produce a ZIP
archive::

   $ ./mach python build/windows_toolchain.py create-zip vs2017_15.8.4

The produced archive will be the argument to ``create-zip`` + ``.zip``.

Firefox for Android with Gradle
===============================

To build Firefox for Android with Gradle in automation, archives
containing both the Gradle executable and a Maven repository
comprising the exact build dependencies are produced and uploaded to
an internal Mozilla server.  The build automation will download,
verify, and extract these archive before building.  These archives
provide a self-contained Gradle and Maven repository so that machines
don't need to fetch additional Maven dependencies at build time.
(Gradle and the downloaded Maven dependencies can be both
redistributed publicly.)

Archiving the Gradle executable is straight-forward, but archiving a
local Maven repository is not.  Therefore a special Task Cluster
Docker image and toolchain job exist for producing the required
archives.  The Docker image definition is rooted in
``taskcluster/docker/android-build``.  The Task Cluster toolchain job
is named `android-gradle-dependencies`.  The job runs in a container
based on the custom Docker image and spawns a Sonatype Nexus proxying
Maven repository process in the background.  The job builds Firefox
for Android using Gradle and the in-tree Gradle configuration rooted
at ``build.gradle``.  The spawned proxying Maven repository downloads
external dependencies and collects them.  After the Gradle build
completes, the job archives the Gradle version used to build, and the
downloaded Maven repository, and exposes them as Task Cluster
artifacts.

To update the version of Gradle in the archive produced, update
``gradle/wrapper/gradle-wrapper.properties``.  Be sure to also update
the SHA256 checksum to prevent poisoning the build machines!

To update the versions of Gradle dependencies used, update
``dependencies`` sections in the in-tree Gradle configuration rooted
at ``build.gradle``.  Once you are confident your changes build
locally, push a fresh build to try.  The `android-gradle-dependencies`
toolchain should run automatically, fetching your new dependencies and
wiring them into the appropriate try build jobs.

To update the version of Sonatype Nexus, update `NEXUS_VERSION` in the
`android-build` Docker image.

To modify the Sonatype Nexus configuration, typically to proxy a new
remote Maven repository, modify
`taskcluster/scripts/misc/android-gradle-dependencies/nexus.xml`.

There is also a toolchain job that fetches the Android SDK and related
packages.  To update the versions of packaged fetched, modify
`python/mozboot/mozboot/android-packages.txt` and update the various
in-tree versions accordingly.
