breadcrumbs: For Developers > page_name: gn-build-configuration title: GN build configuration
This page provides some common build setups for the GN build. It assumes you already got a Chromium checkout.
See also
Recall that in GN, you pick your own build directory. These should generally go in a subdirectory of src/out. You set build arguments on a build directory by typing:
$ gn args out/mybuild
This will bring up an editor. The format of the stuff in the args file is just GN code, so set variables according to normal GN syntax (true/false for booleans, double-quotes for string values, # for comments). When you close the editor, a build will be made in that directory. To change the arguments for an existing build, just re-run this command on the existing directory.
You can get a list of all available build arguments for a given build directory, with documentation, by typing
$ gn args out/mybuild --list
To get documentation for a single flag (in this example, is_component_build):
$ gn args out/mybuild --list=is_component_build
You have to list your build directory as the first argument because the available arguments and their default values are build-specific. For example, setting Android as your target OS might expose new Android-specific build arguments or use different default values.
“GN args” as used on this page are not the command line arguments passed to GN. They refer to the individual variables that are passed as part of the --args command line flag and/or written to the args.gn file.
The component build links many parts of Chrome into separate shared libraries to avoid the long link step at the end. It is the default when compiling debug non-iOS builds and most developers use this mode for everyday builds and debugging. Startup is slower and some linker optimizations won‘t work, so don’t do benchmarks in this mode. Some people like to turn it on for release builds to get both faster links and reasonable runtime performance.
is_component_build = true
The symbol_level setting varies from 0 (no symbols or minimal symbols) to 2 (full symbols). Lower levels make debugging almost impossible, but the build will be much faster. It can be useful in some cases where you just want a build ASAP (many build bots do this).
symbol_level = 0
enable_nacl = false
blink_symbol_level=0
By default, the GN build will match that of the host OS and CPU architecture. To override:
target_cpu = “x86”
Possible values for the target_cpu:
Windows supports “x86” and “x64”. Since building is only supported on 64-bit machines, the default will always be “x64”.
Mac and desktop Linux supports only “x64”. On desktop Linux you might also theoretically try any of the ARM or MIPS architecture strings form the Android section below, but these aren't supported or tested and you will also need a sysroot.
Chrome OS supports “x86” and “x64”, but to build a 32-bit binary you will need to use a sysroot on a 64-bit machine.
If you specify an Android build (see below) the default CPU architecture will be “arm”. You could try overriding it to “arm64”, “x86”, “mipsel”, or “mips64el” but the GN builds for these aren't regularly tested.
This build requires that you are a Googler with src-internal checked out.
Use these args for official builds:
is_official_build = true is_chrome_branded = true is_debug = false
For 32-bit official builds, append this arg to the above set:
target_cpu = “x86”
On Windows and Mac you also need to add the following entry to your .gclient file to automatically fetch the PGO profiles required to do an official build:
solutions = [ { “name”: “src”, # ... “custom_vars”: { “checkout_pgo_profiles”: True, }, }, ],
chrome_pgo_phase = 0
There is a ‘gn gen’ argument (--ide) for producing Visual Studio project and solution files:
$ gn gen out\mybuild --ide=vs
Projects are configured for VS 2015 by default.
See this page for more information on configuring Chromium builds for Windows.
This assumes you've already followed the Android build instructions to check out.
# Add this to get Android stuff checked out.
This will build the Chrome OS variant of the browser that is distributed with the operating system. You can run it on your Linux desktop for feature development.
target_os = “chromeos”
Checkouts which are used to build Chrome OS builds must also have 'chromeos'
added to the target_os
list in the .gclient file. After making this change, you will need to run gclient sync
once.
solutions = [ ...existing stuff in here... ] target_os = [‘chromeos’] # Or if you also build e.g. android, this might be # target_os = [‘android’, ‘chromeos’]