HipHop for PHP: Move Fast

Introduced HipHop for PHP, a source code transformer that converts PHP to highly optimized C++ for compilation. This significantly reduces CPU usage (average 50%) and server overhead, enabling faster iteration and scaling of complex PHP applications. It includes a code transformer, a reimplementation of PHP's runtime system, and rewrites of common PHP extensions. Also developed HPHPi, an experimental interpreter for development to catch bugs and provide a seamless development experience.