icecream-chromium-mac

These instructions can be used to build Chromium or Chromium-based projects on Mac using icecream, possibly in combination with ccache. Compilation can be distributed to macOS and Linux hosts. It was inspired by a similar effort found at https://github.com/darktears/icecream-mac.

What happens when I follow these instructions?

You'll install a modified version of the icecc client on Mac that is up to date and has changes to work better with Clang plugins as used by Chromium
You'll use a script when building Chromium which builds two icecc compilation environments: one for Mac (using the Clang compiler for Mac found in your local Chromium repository) and one for Linux (using a matching Clang compiler for Linux downloaded from Google, similar to what a Chromium build on Linux would do)

Icecream setup on Mac client

On the client (the machine you're running the build on), you'll need to install a recent version of icecream. At the moment of writing the latest release, 1.1, doesn't include some of the fixes that are needed to make this work. I've prepared an unofficial '1.2pre' release from icecream's master branch as of 3 January 2018 (see the forked repository).

I assume you have Homebrew installed. Install icecream using Homebrew:

$ brew install avl7771/homebrew-icecream/icecream

Now start the iceccd daemon, as root:

$ sudo brew services start icecream

Check using ps whether iceccd is running on your machine.

Now clone this repository which contains scripts to create the icecream environment pakages from Chromium's clang binaries, so that we can use the included clang version to compile on Mac and Linux:

$ git clone https://github.com/avl7771/icecream-chromium-mac

Icecream setup on Mac or Linux hosts

You'll need icecream 1.1 or newer on any host you want to participate. Install and start it as normal. At least one host will need to run an icecc scheduler.

Building with icecream

You'll need to set the following GN arguments to make building with icecc possible. Set these using gn args:

enable_precompiled_headers=false
ffmpeg_use_atomics_fallback=true

In addition, if you don't use ccache, also set

cc_wrapper="icecc"

If you do use ccache, put this in your ccache.conf:

prefix_command=icecc

Alternatively you can use the CCACHE_PREFIX environment variable to get the same effect.

Finally, you'll need to set the ICECC_VERSION environment variable to use custom-built environments when you're running ninja to build. It's set like this, using the scripts and files from this repository:

$ export ICECC_VERSION=`path/to/geticeccversion.sh path/to/chromium/src`

To make sure that you're always using the correct environment for the repository you're building from, I recommend setting it for your ninja build only:

$ ICECC_VERSION=`path/to/geticeccversion.sh path/to/chromium/src` ninja -j30 -C out/Debug chrome

Vary the -j parameter to find something fitting for the number of hosts available. That's it, enjoy your distributed compile!