HHVM's OS X support is still fairly experimental. It should be fine for development, but Linux is still the recommended OS for production usage.

To install,

brew tap hhvm/hhvm
brew install hhvm

And then wait a long time for it to compile since we don't provide bottles yet. (This will be anywhere from twenty minutes on a beefy Mac Pro to a couple of hours on a MacBook Air.)

• Only issues with the packaging itself which don't require a change to HHVM should be reported here. This includes things like missing dependencies or an out-of-date formula.
• Most issues should be reported directly to the HHVM project since they will need to be fixed there. This includes everything from "this code doesn't work on OS X" to "--HEAD doesn't build".

• HHVM homepage
• HHVM github project
• Homebrew homepage