phc is an open source PHP compiler with support for plugins. In addition, it can be used to pretty-print or obfuscate PHP code, as a framework for developing applications that process PHP scripts, or to convert PHP into XML and back, enabling processing of PHP scripts using XML tools.

phc for PHP programmers:
- Compile PHP source into an (optimized) executable (supports entire PHP standard library).
- Compile a web application into an (optimized) extension (supports entire PHP standard library).
- Pretty-print PHP code.
- Obfuscate PHP code (--obfuscate flag - experimental).
- Combine many php scripts into a single file (--include flag - experimental).
- Optimize PHP code using classical compiler optimizations (in the dataflow branch - very experimental).

phc for tools developers:
- Analyse, modify or refactor PHP scripts using C++ plugins.
- Convert PHP into a well-defined XML format, process it with your own tools, and convert it back to PHP.
- Operate on ASTs, simplified ASTs, or 3-address code.
- Analyse or optimize PHP code using an SSA-based IR (in the dataflow branch - very experimental).