Checking out and building Thorium for Mac

There are instructions for other platforms here in the Thorium Docs directory.

System requirements

  • A Mac, Intel or Arm. (More details about Arm Macs.)

  • MacOS 10.15 or higher.

  • Xcode. Xcode comes with...

  • The macOS SDK. Run

    $ ls `xcode-select -p`/Platforms/MacOSX.platform/Developer/SDKs

    to check whether you have it, and what version you have. mac_sdk_official_version in mac_sdk.gni is the SDK version used on all the bots and for official builds, so that version is guaranteed to work. Building with a newer SDK usually works too (please fix or file a bug if it doesn't).

    Building with an older SDK might also work, but if it doesn't then we won't accept changes for making it work.

    The easiest way to get the newest SDK is to use the newest version of Xcode, which often requires using the newest version of macOS. We don't use Xcode itself much, so if you're know what you're doing, you can likely get the build working with an older version of macOS as long as you get a new version of the macOS SDK on it.

  • An APFS-formatted volume (this is the default format for macOS volumes).

Downloading the Thorium code

Using Git:

git clone --recursive https://github.com/Alex313031/thorium.git

Install depot_tools

Clone the depot_tools repository:

$ git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git

Add depot_tools to the end of your PATH (you will probably want to put this in your ~/.bash_profile or ~/.zshrc). Assuming you cloned depot_tools to /path/to/depot_tools (note: you must use the absolute path or Python will not be able to find infra tools): 

$ export PATH="$PATH:/path/to/depot_tools"

Get the Chromium code

Create a chromium directory for the checkout and change to it (you can call this whatever you like and put it wherever you like, as long as the full path has no spaces):

$ mkdir chromium && cd chromium

Run the fetch tool from depot_tools to check out the code and its dependencies.

$ caffeinate fetch chromium

Running the fetch with caffeinate is optional, but it will prevent the system from sleeping for the duration of the fetch command, which may run for a considerable amount of time.

If you don't need the full repo history, you can save time by using fetch --no-history chromium. You can call git fetch --unshallow to retrieve the full history later.

Expect the command to take 30 minutes on even a fast connection, and many hours on slower ones.

When fetch completes, it will have created a hidden .gclient file and a directory called src in the working directory. The remaining instructions assume you have switched to the src directory: 

$ cd src

Optional: You can also build with API keys if you want your build to talk to some Google services like Google Sync, Translate, and GeoLocation.   Thorium has its own keys in a private repository, if you are a builder or would like access to them, contact me. Otherwise, for personal or development builds, you can create your own keys and add yourself to google-browser-signin-testaccounts to enable Sync.

Setting up the build

First, we need to make sure we have all the tags/branches and are on Tip of Tree. For this, run (from within the Thorium repo):

./trunk.sh

Secondly, we need to check out the revision that Thorium is currently using. For this, run:

./version.sh

At the end it will download the PGO profiles for Chromium for all platforms. The file for MacOS will be downloaded to /Users/$USERNAME/chromium/src/build/pgo_profiles/*.profdata with the actual file name looking something like 'chrome-mac-6167-1706032279-25144dc1c87be275c5981becbafed7785e2f39f2.profdata', which should be added to the end of args.gn as per below. Take note of this, as we will be using it in the args.gn below.

Lastly, we need to copy the Thorium source files over the Chromium tree. For this, run:

./setup.sh --mac

This will copy all the files and patches to the needed locations.

  • NOTE: To build for arm64, use ./setup.sh --mac as well. Use ./setup.sh --help to see all options/platforms.

Chromium uses Ninja as its main build tool along with a tool called GN to generate .ninja files. You can create any number of build directories with different configurations. Create the build output directory by running: 

$ gn args out/thorium

The contents of 'mac_args.gn' in the root of this repo should be copy/pasted into the editor. and edit the last line to point to the actual path and file name of the '*.profdata' it
Use the 'mac_ARM_args.gn' for arm64 builds.

  • For other build arguments, including release settings, see GN build configuration. The default will be a debug component build matching the current host operating system and CPU.
  • For more info on GN, run gn help on the command line or read the quick start guide.
  • Building Thorium for arm64 Macs requires additional setup.

Build Thorium

Build Thorium (the "chrome" target) with Ninja using the command:

$ autoninja -C out/thorium thorium chromedriver

(autoninja is a wrapper that automatically provides optimal values for the arguments passed to ninja.)

You can get a list of all of the other build targets from GN by running gn ls out/thorium from the command line. To compile one, pass the GN label to Ninja with no preceding "//" (so, for //chrome/test:unit_tests use autoninja -C out/thorium chrome/test:unit_tests).

Run/Install Thorium

Once it is built, you can simply run the browser:

$ out/thorium/Thorium.app/Contents/MacOS/Thorium

To generate a .dmg installation package, run (from within the Thorium repo):

$ ./build_dmg.sh

Avoiding repetitive system permissions dialogs after each build

Every time you start a new developer build, you may get two system dialogs: Thorium wants to use your confidential information stored in "Thorium Safe Storage" in your keychain., and Do you want the application "Thorium.app" to accept incoming network connections?.

To avoid them, you can run Thorium with these command-line flags (but of course beware that they will change the behavior of certain subsystems, like password storage):

--use-mock-keychain --disable-features=DialMediaRouteProvider

Debugging

Good debugging tips can be found here.

If you have problems building, join us in the Thorium IRC Channel at #thorium on irc.libera.chat and ask there.

Build and run test targets

Tests are split into multiple test targets based on their type and where they exist in the directory structure. To see what target a given unit test or browser test file corresponds to, the following command can be used: 

$ gn refs out/thorium --testonly=true --type=executable --all chrome/browser/ui/browser_list_unittest.cc
//chrome/test:unit_tests

In the example above, the target is unit_tests. The unit_tests binary can be built by running the following command:

$ autoninja -C out/thorium unit_tests

You can run the tests by running the unit_tests binary. You can also limit which tests are run using the --gtest_filter arg, e.g.:

$ out/thorium/unit_tests --gtest_filter="BrowserListUnitTest.*"

You can find out more about GoogleTest at its GitHub page.

Update your checkout

To update an existing checkout, you can run (from within the Thorium repo):

$ ./trunk.sh

Tips, tricks, and troubleshooting

Improving performance of git status

Increase the vnode cache size

git status is used frequently to determine the status of your checkout. Due to the large number of files in Chromium's checkout, git status performance can be quite variable. Increasing the system's vnode cache appears to help. By default, this command: 

$ sysctl -a | egrep 'kern\..*vnodes'

Outputs kern.maxvnodes: 263168 (263168 is 257 * 1024). To increase this setting:

$ sudo sysctl kern.maxvnodes=$((512*1024))

Higher values may be appropriate if you routinely move between different Chromium checkouts. This setting will reset on reboot. To apply it at startup:

$ sudo tee /Library/LaunchDaemons/kern.maxvnodes.plist > /dev/null <<EOF
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  <dict>
    <key>Label</key>
      <string>kern.maxvnodes</string>
    <key>ProgramArguments</key>
      <array>
        <string>sysctl</string>
        <string>kern.maxvnodes=524288</string>
      </array>
    <key>RunAtLoad</key>
      <true/>
  </dict>
</plist>
EOF

Or edit the file directly.

Configure git to use an untracked cache

Try running

$ git update-index --test-untracked-cache

If the output ends with OK, then the following may also improve performance of git status:

$ git config core.untrackedCache true

Configure git to use fsmonitor

You can significantly speed up git by using fsmonitor. You should enable fsmonitor in large repos, such as Chromium and v8. Enabling it globally will launch many processes and probably isn't worthwhile. The command to enable fsmonitor in the current repo is: 

$ git config core.fsmonitor true

Xcode license agreement

If you're getting the error

Agreeing to the Xcode/iOS license requires admin privileges, please re-run as root via sudo.

the Xcode license hasn't been accepted yet which (contrary to the message) any user can do by running:

$ xcodebuild -license

Only accepting for all users of the machine requires root:

$ sudo xcodebuild -license

Exclude checkout from Spotlight indexing

Chromium's checkout contains a lot of files, and building generates many more. Spotlight will try to index all of those files, and uses a lot of CPU time doing so, especially during a build, which can slow things down.

To prevent the Chromium checkout from being indexed by Spotlight, open System Preferences, go to "Spotlight" -> "Privacy" and add your Chromium checkout directory to the list of excluded locations.