There are instructions for other platforms linked from the get the code page.
Are you a Google employee? See go/building-chrome instead.
A 64-bit Mac running 10.12+.
Xcode 8+
The OS X 10.12 SDK. Run
$ ls `xcode-select -p`/Platforms/MacOSX.platform/Developer/SDKs
to check whether you have it. Building with a newer SDK works too, but the releases currently use the 10.12 SDK.
depot_toolsClone 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"
Ensure that unicode filenames aren't mangled by HFS:
$ git config --global core.precomposeUnicode true
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 chromium
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 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.
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. To create a build directory:
$ gn gen out/Default
Default with another name, but it should be a subdirectory of out.gn help on the command line or read the quick start guide.Full rebuilds are about the same speed in Debug and Release, but linking is a lot faster in Release builds.
Put
is_debug = false
in your args.gn to do a release build.
Put
is_component_build = true
in your args.gn to build many small dylibs instead of a single large executable. This makes incremental builds much faster, at the cost of producing a binary that opens less quickly. Component builds work in both debug and release.
Put
symbol_level = 0
in your args.gn to disable debug symbols altogether. This makes both full rebuilds and linking faster (at the cost of not getting symbolized backtraces in gdb).
Jumbo builds merge many translation units (“source files”) and compile them together. Since a large portion of Chromium's code is in shared header files, this dramatically reduces the total amount of work needed. Check out the Jumbo / Unity builds for more information.
Enable jumbo builds by setting the GN arg use_jumbo_build=true.
You might also want to install ccache to speed up the build.
Build Chromium (the “chrome” target) with Ninja using the command:
$ autoninja -C out/Default chrome
(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/Default 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/Default chrome/test:unit_tests).
Once it is built, you can simply run the browser:
$ out/Default/Chromium.app/Contents/MacOS/Chromium
You can run the tests in the same way. You can also limit which tests are run using the --gtest_filter arg, e.g.:
$ out/Default/unit_tests --gtest_filter="PushClientTest.*"
You can find out more about GoogleTest at its GitHub page.
Good debugging tips can be found here. If you would like to debug in a graphical environment, rather than using lldb at the command line, that is possible without building in Xcode (see Debugging in Xcode).
Tips for printing variables from lldb prompt (both in Xcode or in terminal):
uptr is a std::unique_ptr, the address it wraps is accessible as uptr.__ptr_.__value_.base::string16, ensure you have a ~/.lldbinit file and add the following line into it (substitute {SRC} for your actual path to the root of Chromium's sources):command script import {SRC}/tools/lldb/lldb_chrome.py
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.
While using Xcode is unsupported, GN supports a hybrid approach of using Ninja for building, but Xcode for editing and driving compilation. Xcode is still slow, but it runs fairly well even with indexing enabled. Most people build in the Terminal and write code with a text editor, though.
With hybrid builds, compilation is still handled by Ninja, and can be run from the command line (e.g. autoninja -C out/gn chrome) or by choosing the chrome target in the hybrid workspace and choosing Build.
To use Xcode-Ninja Hybrid pass --ide=xcode to gn gen:
$ gn gen out/gn --ide=xcode
Open it:
$ open out/gn/ninja/all.xcworkspace
You may run into a problem where http://YES is opened as a new tab every time you launch Chrome. To fix this, open the scheme editor for the Run scheme, choose the Options tab, and uncheck “Allow debugging when using document Versions Browser”. When this option is checked, Xcode adds --NSDocumentRevisionsDebugMode YES to the launch arguments, and the YES gets interpreted as a URL to open.
If you have problems building, join us in #chromium on irc.freenode.net and ask there. Be sure that the waterfall is green and the tree is open before checking out. This will increase your chances of success.
git statusgit 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 2.8 or higher, 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
If git --version reports 2.6 or higher, but below 2.8, you can instead run
$ git update-index --untracked-cache
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