Flexible Type Analysis Karl Crary Carnegie Mellon University

Abstract Run-time type dispatch enables a variety of advanced optimization techniques for polymorphic languages, including tag-free garbage collection, unboxed function arguments, and flattened data structures. However, modern type-preserving compilers transform types between stages of compilation, making type dispatch prohibitively complex at low levels of typed compilation. It is crucial therefore for type analysis at these low levels to refer to the types of previous stages. Unfortunately, no current intermediate language supports this facility