https://github.com/occisor2/clc

A small C compiler in Common Lisp
https://github.com/occisor2/clc

c-language c-programming c-programming-language common-lisp compiler compilers programming-language programming-languages

Last synced: about 10 hours ago
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A small C compiler in Common Lisp

• Host: GitHub
• URL: https://github.com/occisor2/clc
• Owner: occisor2
• Created: 2024-06-23T14:39:40.000Z (3 months ago)
• Default Branch: master
• Last Pushed: 2024-08-29T23:26:48.000Z (27 days ago)
• Last Synced: 2024-09-24T21:16:54.829Z (about 15 hours ago)
• Topics: c-language, c-programming, c-programming-language, common-lisp, compiler, compilers, programming-language, programming-languages
• Language: Common Lisp
• Homepage:
• Size: 57.6 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.org

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README

        
#+TITLE:     CLC Compiler

#+AUTHOR:    Russell Smith

#+EMAIL:     [email protected]

#+DESCRIPTION: A small C compiler written in Common Lisp 

#+KEYWORDS:  C, Compiler, Lisp

#+LANGUAGE:  en

#+OPTIONS:   H:4 num:nil toc:2 p:t

* Summary

** Current Features

- Variables: No intialization at all; no global variables; can be

  defined anywhere in the function

- Types: Only int supported right now

- Functions: No multiple or separate definitions from implementation;

  only 6 or less arguments in calls; only int return type, no void;

  since no declaring functions, you can't link against other libraries

  yet

- Operators: Currently supported: +, -, *

- Control Flow: If statements with optional else; if and else must

  have a compound statement following them

- Error Handling: Syntax and other errors generate Common Lisp

  conditions as of now, so are not very user friendly

  

The entire compilation pipeline is implemented, so all these features

compile to assembly code. The compiler is really just a fancy

calculator with basic control flow right now. You can get program

output by returning values from main. No runtime has been implemented

yet, so you need to link against gcc or clang's.

* About

I've been trying to write a C compiler for about a year, but either

got busy or stuck with a design issue. I've finally got something

working though small with this project and have big goals for the

future.

** Why Lisp?

I've always found Lisp really interesting, especially Common Lisp. The

REPL oriented development style of Lisp also made trying new things

during development a lot easier compared to C++, which is what I was

using.

** Future Goals

- Implement a much larger subset of the language

- Improve the diagnostic messages

- Add optimization passes after the IR generation stage, specifically

  constant propogation, mem2reg, and dead code elimination.

- Implement my own crt0 and small LibC

** Resources

For the frontend, I learned most of what I know about and lexing and

parsing, specifically Pratt Parsing, from Robert Nystrom's /Crafting

Interpreters/. My AST and symbol handling design is some of my own,

probaly not very original, and based on other various sources. My IR

is very inspired by LLVM without the SSA format, and a large portion

of my assembly code generator is based on the methods described in

Nora Sandler's /Writing a C Compiler/. I learned most of the weird

language semantics related to C from Nora's book too.

* Automatic Installation

Clone the repository into ~/quicklisp/local-projects then load and

install dependencies via quicklisp.

#+BEGIN_SRC lisp

  (ql:quickload 'clc)

#+END_SRC