docs/building.md

# Building Dawn

Dawn uses the Chromium build system and dependency management so you need to [install depot_tools] and add it to the PATH.

[install depot_tools]: http://commondatastorage.googleapis.com/chrome-infra-docs/flat/depot_tools/docs/html/depot_tools_tutorial.html#_setting_up

On Linux you need to have the `pkg-config` command:
```sh
# Install pkg-config on Ubuntu
sudo apt-get install pkg-config
```

Then get the source as follows:

```sh
# Clone the repo as "dawn"
git clone https://dawn.googlesource.com/dawn dawn && cd dawn

# Bootstrap the gclient configuration
cp scripts/standalone.gclient .gclient

# Fetch external dependencies and toolchains with gclient
gclient sync
```

Then generate build files using `gn args out/Debug` or `gn args out/Release`.
A text editor will appear asking build options, the most common option is `is_debug=true/false`; otherwise `gn args out/Release --list` shows all the possible options.

On macOS you'll want to add the `use_system_xcode=true` in most cases. (and if you're a googler please get XCode from go/xcode).

Then use `ninja -C out/Release` to build dawn and for example `./out/Release/dawn_end2end_tests` to run the tests.