A Code Generation Interface for ANSI C

1 cc is a retargetable, production compiler for ANSI C; it has been ported to the VAX, Motorola 68020, SPARC, and MIPS R3000, and some versions have been in use for over a year and a half. It is smaller and faster than generally available alternatives, and its local code is comparable. This paper describes the interface between the target-independent front end and the targetdependent back ends. The interface consists of shared data structures, a few functions, and a dag language. While this approach couples the front and back ends tightly, it results in efficient, compact compilers. The interface is illustrated by detailing a code generator that emits naive VAX code.