COMP 3101 · The Art of Abstraction: How Compilers Think

Led by Lattnerian Compiler Simulacrum

What is an intermediate representation — and why is it the most powerful idea in compiler design? Based on the writings of Chris Lattner.

1. Module 1

   What Is an Intermediate Representation?

   Led by Lattnerian Compiler Simulacrum

   The question

   Why does a compiler need an intermediate representation? What does "language-neutral, machine-neutral" mean — and what does this level of abstraction enable that direct translation would not?

   Outcome

   The student can explain what an intermediate representation is and what it enables.

   Sub-units

   1. ○ 1.1 Three Phases Open this unit → ✓ ↻
   2. ○ 1.2 Why IR Enables Sharing Open this unit → ✓ ↻
   Begin the course → Print certificate of completion
2. Module 2

   LLVM: The Architecture

   Led by Lattnerian Compiler Simulacrum

   The question

   LLVM's modularity made it adaptable to hardware and languages that didn't exist when it was written. Every component is replaceable. Why does modularity produce adaptability — and what would a monolithic design have prevented?

   Outcome

   The student can describe LLVM's architecture and explain the optimisation pass concept.

   Sub-units

   1. ○ 2.1 The Pass Architecture Open this unit → ✓ ↻
   2. ○ 2.2 Essay: Why Modularity Matters Open this unit → ✓ ↻
   Open this module → Print certificate of completion
3. Module 3

   MLIR: Multi-Level IR

   Led by Lattnerian Compiler Simulacrum

   The question

   MLIR allows multiple IRs at multiple levels of abstraction. A TensorFlow model passes through TF dialect → Linalg → LLVM IR → machine code. What does each level see that the others cannot?

   Outcome

   The student can explain MLIR and why multiple abstraction levels outperform a single IR.

   Sub-units

   1. ○ 3.1 Why Multiple Levels? Open this unit → ✓ ↻
   Open this module → Print certificate of completion
4. Module 4

   IR as a General Concept

   Led by Lattnerian Compiler Simulacrum

   The question

   Any complex translation benefits from an intermediate stage that makes meaning explicit. Design an IR for a non-software domain: legal, medical, educational. What information does it preserve, add, and enable?

   Outcome

   The student can apply the IR concept to a non-software domain.

   Sub-units

   1. ○ 4.1 Design a Non-Software IR Open this unit → ✓ ↻
   Open this module → Print certificate of completion
5. Module 5

   Elegance and Abstraction

   Led by Lattnerian Compiler Simulacrum

   The question

   LLVM's success is due to the elegance of the IR — it is at exactly the right level of abstraction. Too low exposes unnecessary detail. Too high hides information needed for optimisation. What makes an abstraction right?

   Outcome

   The student can take a defended position on what makes an abstraction the right one.

   Sub-units

   1. ○ 5.1 Final Essay: What Makes an Abstraction Right? Open this unit → ✓ ↻
   Open this module → Print certificate of completion