🐮 Cow Compiler

Welcome to the Cow Compiler — a lightweight compiler written in C that compiles a minimalistic language called CowLang into LLVM IR.

This project walks you through a complete compilation pipeline, making it ideal for learning how compilers work at a low level.

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🔧 Compilation Pipeline

This compiler includes the following stages:

• Lexer: Tokenizes the input source code.
• Parser: Parses tokens into an abstract syntax tree (AST)
• AST: Represents the structure of the program
• IR Generation: Converts the AST into a simple intermediate representation (IR)
• LLVM Code Emission: Emits LLVM IR for a simple main() function

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📦 Features

• 🧮 Basic arithmetic expressions (+, -)
• 📝 Variable declarations
• 🧠 Constant folding via IR
• 🧾 LLVM IR code generation (for testing purposes)
• 🔧 Easy to extend (add new operators, variables, data types)

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⚠️ Notes

• The current LLVM IR backend is basic and linked-list-based.
• LLVM output is minimal — a simple main function is emitted.
• You are encouraged to:
  • ✅ Extend the linked list IR to support variable types (VAR)
  • 🔁 Replace switch-case based IR-to-LLVM mapping with real LLVM C API for scalability and real-world usage

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🧠 Example

Input (input.cow)

x = 4 + 4;

Running the Compiler

make        # Compile all source files
make run    # Compile + run the CowLang file

For IR

Custom IR (Extend the Linkedlist for printing):

t0 : const 4 t1 : const 4 t2 : add t0, t1 LLVM IR (saved to output.ll):

define i32 @main() { entry: %t0 = add i32 4, 4 ret i32 %t0 }

🗂️ Project Structure

cow-compiler/
├── front-end/
│   ├── lexer/        # Lexical analyzer
│   ├── parser/       # Syntax parser
│   ├── ast/          # Abstract syntax tree definitions
│   └── token/        # Token types and utilities
├── middle-end/
│   ├── ir/           # Custom intermediate representation (IR)
│   └── irgen/        # AST → IR transformation logic
├── back-end/
│   ├── llvm/         # IR → LLVM IR generator
│   └── evaluator/    # IR evaluator (optional)
├── tests/            # Sample test cases for CowLang
├── src/
│   ├── main.c             # Entry point (main compiler driver)
├── Makefile          # Build system
└── README.md         # Project documentation

💬 Join the Discussion

Have questions, ideas, or suggestions? Want to contribute but don’t know where to start? Let’s talk!

We use GitHub Discussions to foster a collaborative and welcoming community around the Cow Compiler project. Whether you're a beginner learning how compilers work or an experienced contributor looking to improve our IR/LLVM pipeline — you’re welcome here!

🗣️ What You Can Do:

• 💡 Ask Questions
  Not sure how something works? Curious about compiler internals? Ask away!

• 🧠 Share Ideas
  Got a feature request or a suggestion? We’d love to hear your thoughts.

• 🐞 Report Issues
  Found a bug or unexpected behavior? Drop a message before opening an issue.

• 🙌 Collaborate on Features
  Join other developers to brainstorm or discuss new enhancements.

🙌 Contributing

We welcome all contributions — whether you're fixing bugs, improving documentation, or adding exciting new features!