abstractions, such as closures, tuples, and user-defined abstract data types. The type system ensures that well-typed programs cannot violate these abstractions. In addition, the typing constructs admit many low-level compiler optimizations. Our translation to TAL is specified as a sequence of type-preserving transformations, including CPS and closure conversion phases; type-correct source programs are mapped to type-correct assembly language. A key contribution is an approach to polymorphic closure conversion that is considerably simpler than previous work. The compiler and typed assembly language provide a fully automatic way to produce certified code, suitable for use in systems where untrusted and potentially malicious code must be checked for safety before execution. Categories and Subject Descriptors: D.2.11 [Software Engineering]: Software Architectures— Languages; D.3.1 [Programming Languages]: Formal Definitions and Theory—Semantics, Syntax; D.3.2 [Programming Language...
J. Gregory Morrisett, David Walker, Karl Crary, Ne