Syntax-Driven Translation

The compiler's task is to translate the input program into a form where it can execute directly on the target machine. The scanner and parser can analyze the code presented for compilation and determine whether that code constitutes a well-formed program in the source language. If the compiler is to perform translation, optimization, and code generation, however, it must build an ir version of the code for the compiler's later use. That process requires the compiler to reason about the code at a level that is deeper than the context-free syntax. This chapter looks at some of the problems that arise in performing that first translation from source code to ir in the compiler's front end, along with the mechanisms used to solve those problems. It focuses on a particular style of syntax-driven computation that was popularized by parser generators—a style that has become common practice.