Checking out and building Chromium for iOS

There are instructions for other platforms linked from the get the code page.

Instructions for Google Employees

Are you a Google employee? See go/building-chrome instead.

System requirements

  • A 64-bit Mac running 10.11+.

  • Xcode 8.0+.

  • The OS X 10.10 SDK. Run

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

    to check whether you have it. Building with the 10.11 SDK works too, but the releases currently use the 10.10 SDK.

  • The current version of the JDK (required for the Closure compiler).

Install depot_tools

Clone the depot_tools repository:

$ git clone

Add depot_tools to the end of your PATH (you will probably want to put this in your ~/.bashrc or ~/.zshrc). Assuming you cloned depot_tools to /path/to/depot_tools:

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

Get the 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.

$ fetch ios

If you don't want the full repo history, you can save a lot of time by adding the --no-history flag to fetch.

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 install API keys if you want your build to talk to some Google services, but this is not necessary for most development and testing purposes.

Setting up the build

Since the iOS build is a bit more complicated than a desktop build, we provide ios/build/tools/, which will create four appropriately configured build directories under out for Release and Debug device and simulator builds, and generates an appropriate Xcode workspace as well.

This script is run automatically by fetch (as part of gclient runhooks).

You can customize the build by editing the file $HOME/.setup-gn (create it if it does not exist). Look at src/ios/build/tools/setup-gn.config for available configuration options.

From this point, you can either build from Xcode or from the command line using ninja. creates sub-directories named out/${configuration}-${platform}, so for a Debug build for simulator use:

$ ninja -C out/Debug-iphonesimulator gn_all

Note: you need to run script every time one of the file is updated (either by you or after rebasing). If you forget to run it, the list of targets and files in the Xcode solution may be stale.

You can also follow the manual instructions on the Mac page, but make sure you set the GN arg target_os="ios".

Running apps from the commandline

Any target that is built and runs on the bots (see below) should run successfully in a local build. To run in the simulator from the command line, you can use iossim. For example, to run a debug build of Chromium:

$ out/Debug-iphonesimulator/iossim out/Debug-iphonesimulator/

Update your checkout

To update an existing checkout, you can run

$ git rebase-update
$ gclient sync

The first command updates the primary Chromium source repository and rebases any of your local branches on top of tip-of-tree (aka the Git branch origin/master). If you don't want to use this script, you can also just use git pull or other common Git commands to update the repo.

The second command syncs dependencies to the appropriate versions and re-runs hooks as needed.

Tips, tricks, and troubleshooting

If you have problems building, join us in #chromium on and ask there. As mentioned above, be sure that the waterfall is green and the tree is open before checking out. This will increase your chances of success.

Improving performance of git status

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, the startup setting can be set in /etc/sysctl.conf:

$ echo kern.maxvnodes=$((512*1024)) | sudo tee -a /etc/sysctl.conf

Or edit the file directly.

If git --version reports 2.6 or higher, the following may also improve performance of git status:

$ git update-index --untracked-cache

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