DoctorWkt/acwj

A Compiler Writing Journey

In this Github repository, I'm documenting my journey to write a self-compiling compiler for a subset of the C language. I'm also writing out the details so that, if you want to follow along, there will be an explanation of what I did, why, and with some references back to the theory of compilers.

But not too much theory, I want this to be a practical journey.

Here are the steps I've taken so far:

• Part 0: Introduction to the Journey
• Part 1: Introduction to Lexical Scanning
• Part 2: Introduction to Parsing
• Part 3: Operator Precedence
• Part 4: An Actual Compiler
• Part 5: Statements
• Part 6: Variables
• Part 7: Comparison Operators
• Part 8: If Statements
• Part 9: While Loops
• Part 10: For Loops
• Part 11: Functions, part 1
• Part 12: Types, part 1
• Part 13: Functions, part 2
• Part 14: Generating ARM Assembly Code
• Part 15: Pointers, part 1
• Part 16: Declaring Global Variables Properly
• Part 17: Better Type Checking and Pointer Offsets
• Part 18: Lvalues and Rvalues Revisited
• Part 19: Arrays, part 1
• Part 20: Character and String Literals
• Part 21: More Operators
• Part 22: Design Ideas for Local Variables and Function Calls
• Part 23: Local Variables
• Part 24: Function Parameters
• Part 25: Function Calls and Arguments
• Part 26: Function Prototypes
• Part 27: Regression Testing and a Nice Surprise
• Part 28: Adding More Run-time Flags
• Part 29: A Bit of Refactoring
• Part 30: Designing Structs, Unions and Enums
• Part 31: Implementing Structs, Part 1
• Part 32: Accessing Members in a Struct
• Part 33: Implementing Unions and Member Access
• Part 34: Enums and Typedefs
• Part 35: The C Pre-Processor
• Part 36: break and continue
• Part 37: Switch Statements
• Part 38: Dangling Else and More
• Part 39: Variable Initialisation, part 1
• Part 40: Global Variable Initialisation
• Part 41: Local Variable Initialisation
• Part 42: Type Casting and NULL
• Part 43: Bugfixes and More Operators
• Part 44: Constant Folding
• Part 45: Global Variable Declarations, revisited
• Part 46: Void Function Parameters and Scanning Changes
• Part 47: A Subset of sizeof
• Part 48: A Subset of static
• Part 49: The Ternary Operator
• Part 50: Mopping Up, part 1
• Part 51: Arrays, part 2
• Part 52: Pointers, part 2
• Part 53: Mopping Up, part 2
• Part 54: Spilling Registers
• Part 55: Lazy Evaluation
• Part 56: Local Arrays
• Part 57: Mopping Up, part 3
• Part 58: Fixing Pointer Increments/Decrements
• Part 59: Why Doesn't It Work, part 1
• Part 60: Passing the Triple Test
• Part 61: What's Next?
• Part 62: Code Cleanup
• Part 63: A New Backend using QBE
• Part 64: A Backend for the 6809 CPU

I've stopped work on acwj and now I'm writing a new language called alic from scratch. Check it out!

Copyrights

I have borrowed some of the code, and lots of ideas, from the SubC compiler written by Nils M Holm. His code is in the public domain. I think that my code is substantially different enough that I can apply a different license to my code.

Unless otherwise noted,

• all source code and scripts are (c) Warren Toomey under the GPL3 license.
• all non-source code documents (e.g. English documents, image files) are (c) Warren Toomey under the Creative Commons BY-NC-SA 4.0 license.