Introduction

Low Level Virtual Machine

Created by Christ Lattnew in 2003 at the University of Illinois.

BSD style license.

Design

IR: Intermediate Representation

Front end converts source code into IR.

• A lexer converts text into tokens.
• A parser loops over the tokens and creates the AST.
• AST: Abstract syntax tree. Represents the code’s structure.
• Makes it easy to develop a new language.

Middle end analyzes and optimizes.

• Multiple passes.
• Eliminates dead code.
• Performance optimizations.
• Deduplication.
• Loop unrolling (executing iterations in bulk).
• Etc.