They forked PHP into Hack. They've diverged pretty far by this point (especially with data structures), but it maintains some of PHPs quirks and request-oriented runtime. It's jitted by HHVM. Both Hack and HHVM are open-source, but I'm not aware of any major users outside Meta.
They forked PHP into Hack. They've diverged pretty far by this point (especially with data structures), but it maintains some of PHPs quirks and request-oriented runtime. It's jitted by HHVM. Both Hack and HHVM are open-source, but I'm not aware of any major users outside Meta.
Compiled PHP. I'm pretty sure they ran the numbers.