# Checking out and building Chromium for iOS There are instructions for other platforms linked from the [get the code](../get_the_code.md) page. ## Instructions for Google Employees Are you a Google employee? See [go/building-chrome](https://goto.google.com/building-chrome) instead. [TOC] ## System requirements * A 64-bit Mac running 11.3 or later. * [Xcode](https://developer.apple.com/xcode) 13.1 or higher. ## Install `depot_tools` Clone the `depot_tools` repository: ```shell $ 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 `~/.bashrc` or `~/.zshrc`). Assuming you cloned `depot_tools` to `/path/to/depot_tools`: ```shell $ 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): ```shell $ mkdir chromium && cd chromium ``` Run the `fetch` tool from `depot_tools` to check out the code and its dependencies. ```shell $ 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: ```shell $ cd src ``` *Optional*: You can also [install API keys](https://www.chromium.org/developers/how-tos/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/setup-gn.py`, which will create four appropriately configured build directories under `out` for Release and Debug device and simulator builds, and generates an appropriate Xcode project (`out/build/all.xcodeproj`) as well. More information about [developing with Xcode](xcode_tips.md). *Xcode project is an artifact, any changes made in the project itself will be ignored.* You can customize the build by editing the file `$HOME/.setup-gn` (create it if it does not exist). Look at `src/ios/build/tools/setup-gn.config` for available configuration options. From this point, you can either build from Xcode or from the command line using `autoninja`. `setup-gn.py` creates sub-directories named `out/${configuration}-${platform}`, so for a `Debug` build for simulator use: ```shell $ autoninja -C out/Debug-iphonesimulator gn_all ``` (`autoninja` is a wrapper that automatically provides optimal values for the arguments passed to `ninja`.) Note: The `setup-gn.py` script needs to run every time one of the `BUILD.gn` files 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 run the script directly or use either `gclient sync` or `gclient runhooks` which will run `setup-gn.py` for you as part of the update hooks. You can add a custom hook to `.gclient` file to configure `setup-gn.py` to be run as part of `gclient runhooks`. In that case, your `.gclient` file would look like this: ``` solutions = [ { "name" : "src", "url" : "https://chromium.googlesource.com/chromium/src.git", "deps_file" : "DEPS", "managed" : False, "custom_deps" : {}, "custom_vars" : {}, "custom_hooks": [{ "name": "setup_gn", "pattern": ".", "action": [ "python3", "src/ios/build/tools/setup-gn.py", ] }], "safesync_url": "", }, ] target_os = ["ios"] target_os_only = True ``` You can also follow the manual instructions on the [Mac page](../mac_build_instructions.md), but make sure you set the GN arg `target_os="ios"`. ## Building for device To be able to build and run Chromium and the tests for devices, you need to have an Apple developer account (a free one will work) and the appropriate provisioning profiles, then configure the build to use them. ### Code signing identity Please refer to the Apple documentation on how to get a code signing identity and certificates. You can check that you have a code signing identity correctly installed by running the following command. ```shell $ xcrun security find-identity -v -p codesigning 1) 0123456789ABCDEF0123456789ABCDEF01234567 "iPhone Developer: someone@example.com (XXXXXXXXXX)" 1 valid identities found ``` If the command output says you have zero valid identities, then you do not have a code signing identity installed and need to get one from Apple. If you have more than one identity, the build system may select the wrong one automatically, and you can use the `ios_code_signing_identity` gn variable to control which one to use by setting it to the identity hash, e.g. to `"0123456789ABCDEF0123456789ABCDEF01234567"`. ### Mobile provisioning profiles Once you have the code signing identity, you need to decide on a prefix for the application bundle identifier. This is controlled by the gn variable `ios_app_bundle_id_prefix` and usually corresponds to a reversed domain name (the default value is `"org.chromium"`). You then need to request provisioning profiles from Apple for your devices for the following bundle identifiers to build and run Chromium with these application extensions: - `${prefix}.chrome.ios.dev` - `${prefix}.chrome.ios.dev.ContentTodayExtension` - `${prefix}.chrome.ios.dev.CredentialProviderExtension` - `${prefix}.chrome.ios.dev.IntentsExtension` - `${prefix}.chrome.ios.dev.SearchTodayExtension` - `${prefix}.chrome.ios.dev.ShareExtension` - `${prefix}.chrome.ios.dev.TodayExtension` - `${prefix}.chrome.ios.dev.WidgetKitExtension` All these certificates need to have the "App Groups" (`com.apple.security.application-groups`) capability enabled for the following groups: - `group.${prefix}.chrome` - `group.${prefix}.common` The `group.${prefix}.chrome` is only shared by Chromium and its extensions to share files and configurations while the `group.${prefix}.common` is shared with Chromium and other applications from the same organisation and can be used to send commands to Chromium. `${prefix}.chrome.ios.dev.CredentialProviderExtension` needs the AutoFill Credential Provider Entitlement, which corresponds to the key `com.apple.developer.authentication-services.autofill-credential-provider` Please refer to Apple's documentation on how to set this up. ### Mobile provisioning profiles for tests In addition to that, you need a different provisioning profile for each test application. Those provisioning profile will have a bundle identifier matching the following pattern `${prefix}.gtest.${test-suite-name}` where `${test-suite-name}` is the name of the test suite with underscores changed to dashes (e.g. `base_unittests` app will use `${prefix}.gest.base-unittests` as bundle identifier). To be able to run the EarlGrey tests on a device, you'll need two provisioning profiles for EarlGrey and OCHamcrest frameworks: - `${prefix}.test.OCHamcrest` - `${prefix}.test.EarlGrey` In addition to that, then you'll need one additional provisioning profile for the XCTest module too. It must match the pattern: `${prefix}.gtest.${test-suite-name}-module`. ### Other applications Other applications like `ios_web_shell` usually will require mobile provisioning profiles with bundle identifiers that may usually match the following pattern `${prefix}.${application-name}` and may require specific capabilities. Generally, if the mobile provisioning profile is missing then the code signing step will fail and will print the bundle identifier of the bundle that could not be signed on the command line, e.g.: ```shell $ autoninja -C out/Debug-iphoneos ios_web_shell ninja: Entering directory `out/Debug-iphoneos' FAILED: ios_web_shell.app/ios_web_shell ios_web_shell.app/_CodeSignature/CodeResources ios_web_shell.app/embedded.mobileprovision python ../../build/config/ios/codesign.py code-sign-bundle -t=iphoneos -i=0123456789ABCDEF0123456789ABCDEF01234567 -e=../../build/config/ios/entitlements.plist -b=obj/ios/web/shell/ios_web_shell ios_web_shell.app Error: no mobile provisioning profile found for "org.chromium.ios-web-shell". ninja: build stopped: subcommand failed. ``` Here, the build is failing because there are no mobile provisioning profiles installed that could sign the `ios_web_shell.app` bundle with the identity `0123456789ABCDEF0123456789ABCDEF01234567`. To fix the build, you'll need to request such a mobile provisioning profile from Apple. You can inspect the file passed via the `-e` flag to the `codesign.py` script to check which capabilities are required for the mobile provisioning profile (e.g. `src/build/config/ios/entitlements.plist` for the above build error, remember that the paths are relative to the build directory, not to the source directory). If the required capabilities are not enabled on the mobile provisioning profile, then it will be impossible to install the application on a device (Xcode will display an error stating that "The application was signed with invalid entitlements"). ## Running apps from the command line Any target that is built and runs on the bots (see [below](#Troubleshooting)) 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`: ```shell $ out/Debug-iphonesimulator/iossim out/Debug-iphonesimulator/Chromium.app ``` With Xcode 9, `iossim` no longer automatically launches the Simulator. This must now be done manually from within Xcode (`Xcode > Open Developer Tool > Simulator`), and also must be done *after* running `iossim`. ### Passing arguments Arguments needed to be passed to the test application through `iossim`, such as `--gtest_filter=SomeTest.FooBar` should be passed through the `-c` flag: ```shell $ out/Debug-iphonesimulator/iossim \ -c "--gtest_filter=SomeTest.FooBar --gtest_repeat=3" \ out/Debug-iphonesimulator/base_unittests.app ``` ### Running EarlGrey tests EarlGrey tests are run differently than other test targets, as there is an XCTest bundle that is injected into the target application. Therefore you must also pass in the test bundle: ```shell $ out/Debug-iphonesimulator/iossim \ out/Debug-iphonesimulator/ios_chrome_ui_egtests.app \ out/Debug-iphonesimulator/ios_chrome_ui_egtests.app/PlugIns/ios_chrome_ui_egtests_module.xctest ``` ### Running on specific simulator By default, `iossim` will pick an arbitrary simulator to run the tests. If you want to run them on a specific simulator, you can use `-d` to pick the simulated device and `-s` to select the iOS version. For example, to run the tests on a simulated iPhone 6s running iOS 10.0, you would invoke `iossim` like this. ```shell $ out/Debug-iphonesimulator/iossim -d 'iPhone 6s' -s '10.0' \ out/Debug-iphonesimulator/base_unittests.app ``` Please note that by default only a subset of simulator devices are installed with Xcode. You may have to install additional simulators in Xcode (or even an older version of Xcode) to be able to run on a specific configuration. Go to "Preferences > Components" tab in Xcode to install other simulator images (this is the location the setting is in Xcode 9.2; it may be different in other version of the tool). ## Update your checkout To update an existing checkout, you can run ```shell $ 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/main`). 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 Remember that the XCode project you interact with while working on Chromium is a build artifact, generated from the `BUILD.gn` files. Do not use it to add new files; instead see the procedures for [working with files](working_with_files.md). If you have problems building, join us in `#chromium` on `irc.freenode.net` and ask there. As mentioned above, be sure that the [waterfall](https://build.chromium.org/buildbot/waterfall/) is green and the tree is open before checking out. This will increase your chances of success. ### Debugging To help with deterministic builds, and to work with Goma, the path to source files in debugging symbols are relative to source directory. To allow Xcode to find the source files, you need to ensure to have an `~/.lldbinit-Xcode` file with the following lines into it (substitute {SRC} for your actual path to the root of Chromium's sources): ``` script sys.path[:0] = ['{SRC}/tools/lldb'] script import lldbinit ``` This will also allow you to see the content of some of Chromium types in the debugger like `std::u16string`, ... If you want to use `lldb` directly, name the file `~/.lldbinit` instead of `~/.lldbinit-Xcode`. Note: if you are using `ios/build/tools/setup-gn.py` to generate the Xcode project, the script also generate an `.lldbinit` file next to the project and configure Xcode to use that file instead of the global one. ### Changing the version of Xcode To change the version of Xcode used to build Chromium on iOS, please follow the steps below: 1. Launch the new version of Xcode.app. This is required as Xcode may need to install some components into the system before the new version can be used from the command-line. 1. Reboot your computer. This is required as some of Xcode components are daemons that are not automatically stopped when updating Xcode, and command-line tools will fail if the daemon version is incompatible (usually `actool` fails). 1. Run `gn gen`. This is required as the `ninja` files generated by `gn` encodes some information about Xcode (notably the path to the SDK, ...) that will change with each version. It is not possible to have `ninja` re-run `gn gen` automatically when those changes unfortunately. If you have a downstream chekout, run `gclient runhooks` instead of `gn gen` as it will ensure that `gn gen` will be run automatically for all possible combination of target and configuration from within Xcode. If you skip some of those steps, the build may occasionally succeed, but it has been observed in the past that those steps are required in the vast majority of the situation. Please save yourself some painful build debugging and follow them. If you use `xcode-select` to switch between multiple version of Xcode, you will have to follow the same steps. ### 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: ```shell $ sysctl -a | egrep kern\..*vnodes ``` Outputs `kern.maxvnodes: 263168` (263168 is 257 * 1024). To increase this setting: ```shell $ 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`: ```shell $ echo kern.maxvnodes=$((512*1024)) | sudo tee -a /etc/sysctl.conf ``` Or edit the file directly. #### Configure git to use an untracked cache If `git --version` reports 2.8 or higher, try running ```shell $ git update-index --test-untracked-cache ``` If the output ends with `OK`, then the following may also improve performance of `git status`: ```shell $ git config core.untrackedCache true ``` If `git --version` reports 2.6 or higher, but below 2.8, you can instead run ```shell $ 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: ```shell $ xcodebuild -license ``` Only accepting for all users of the machine requires root: ```shell $ sudo xcodebuild -license ```