As mentioned elsewhere in the thread, hiphop is a name of a project, its not just a php-to-c++ compiler. hphp was a program built from hiphop that compiled php

As mentioned elsewhere in the thread, hiphop is a name of a project, its not just a php-to-c++ compiler. hphp was a program built from hiphop that compiled php to c++. This is being completely ripped out of hiphop. hhvm is also built from the hiphop source. It is a JIT for php, and currently the main focus of the hiphop project. The rest is still of course true, you cant just switch to hiphop it supports an incomplete set of php which is enough for facebook, but not the average library that you want to import via composer(also doesnt support composer, due to no namespaces yet).