docs/mac_build_instructions.md

# Checking out and building Chromium for Mac

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 Intel Mac running 10.15.4+. (Building on Arm Macs is
    [not yet supported](https://chromium.googlesource.com/chromium/src.git/+/master/docs/mac_arm64.md).)
*   [Xcode](https://developer.apple.com/xcode/) 12.2+. This version of Xcode
    comes with ...
*   The macOS 11.0 SDK. Run

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

    to check whether you have it. Building with a newer SDK usually works too
    (please fix it if it doesn't), but the releases
    [currently use Xcode 12.2](https://source.chromium.org/search?q=MAC_BINARIES_LABEL&ss=chromium)
    and the macOS 11.0 SDK.

## 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 `~/.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):

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

## Get the code

Ensure that unicode filenames aren't mangled by HFS:

```shell
$ 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):

```shell
$ mkdir chromium && cd chromium
```

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

```shell
$ 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:

```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

Chromium uses [Ninja](https://ninja-build.org) as its main build tool along with
a tool called [GN](https://gn.googlesource.com/gn/+/master/docs/quick_start.md)
to generate `.ninja` files. You can create any number of *build directories*
with different configurations. To create a build directory:

```shell
$ gn gen out/Default
```

* You only have to run this once for each new build directory, Ninja will
  update the build files as needed.
* You can replace `Default` with another name, but
  it should be a subdirectory of `out`.
* For other build arguments, including release settings, see [GN build
  configuration](https://www.chromium.org/developers/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](https://gn.googlesource.com/gn/+/master/docs/quick_start.md).
* Building Chromium for arm Macs requires [additional setup](mac_arm64.md).


### Faster builds

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