eta compiler

As part of a course project, I worked with a team of four to build a compiler for a language called Eta, an imperative, procedural language similar to C. The compiler targets x86-64 and supports the System V calling convention.

The compiler was implemented in Rust using the pest parser. Pest takes as input a parsing expression grammar (PEG) over a more typical BNF grammar. Some of the syntax of Eta is described in this snippet of the grammar:

uses = { use_expr* }
definitions = { definition+ }
program = { SOI ~ uses ~ definitions ~ EOI }

interface_definitions = { interface_function+ }
interface = { SOI ~ interface_definitions ~ EOI}

The compiler used a custom IR based on the specification in Appel’s Modern Compiler Implementation in Java text. We implemented optimizations and extensions on the compiler as well, including:

• Linear Scan Register Allocation
• SSA conversion
• Function inlining
• Dead Code Elimination
• Support for object-oriented features including record types

Building a compiler is no small task, but this course got me into programming languages and compilers as a discipline. If your university has a compilers course, you should take it!