9 Simulating Tailcalls in C

Abstract

Implementations of modern high-level languages sometimes generate C as their ‘machine code’. While this can lead to a reasonable degree of portability and efficiency of the generated code, some features are difficult to express correctly, portably, and efficiently in C. One such feature is the tailcall, which is present in most functional and logic programming languages. This chapter describes and evaluates a number of techniques for simulating tailcalls in C.

Since RML can only express loops by tailcalls, and our compiler uses a continuation-passing style intermediate representation, efficient and correct implementation of tailcalls is of utmost importance to the rml2c compiler.