A Principled, Complete, and Efficient Representation of C++

We present a systematic representation of C++, called IPR, for complete semantic analysis and semantics-based transformations. We describe the ideas and design principles that shaped the IPR. In particular, we describe how general type-based unification is key to minimal compact representation, fast type-safe traversal, and scalability. The IPR is general enough to handle real-world programs involving many translation units, archaic programming styles, and generic programming using likely C++0x extensions that affect the type system. The difficult issue of how to represent irregular (ad hoc) features in a systematic (non ad hoc) manner is among key contributions of this paper. The IPR can represent all of C++ with just slightly less than 200 node types; to compare the ISO C++ grammar has over 700 productions. Finally, we report impacts of this work on existing C++ compilers.