How does it compare to HipHop or fb's newest offering?

Terr_ · on March 24, 2014

IIRC:

1. Normally, PHP becomes opcodes for the PHP interpreter to run.

2. Quercus takes PHP code and generates .java source files from it, which then run in the JVM like other Java code.

3. The earlier HipHop (HPHPc) compiles PHP to C++ source

4. The more-recently-released HipHop Virtual Machine (HHVM) is an alternative to PHP's typical interpreter.