The IR Tree: Named Nodes and Namespaces

Working out effective name handling mechanisms in Cone’s IR took several tries. The key challenges: Although most node types don’t use names, the ones that do are spread out unevenly across every node group: a few expressions (variables and functions), most types, and some statements (e.g., module nodes). What is the best way to make a node’s name information generically accessible regardless of node type, without wasting a lot of space for non-named nodes?

The IR Tree: The INode Interface

Having spoken about the compiler’s IR tree in general terms, let’s focus in on an important detail: how to represent a node that could be any arbitary type. Cone’s IR makes use of dozens of different types of nodes, each defined using a different struct. However, sometimes the compiler needs to point to a node without restricting which type of node it must be. For example, consider an assignment node.

The IR Tree - Introduction

The Cone compiler uses a traditional pipeline to transform source programs into object files. The Intermediate Representation (IR) plays a central role in this design. It is the glue binding together the parser, semantic analysis passes, and the LLVM IR generator. The literature on effective IR design is relatively sparse as compared to other topics, such as parsing, type inference/theory, and optimization techniques. This is a shame. I have devoted far more time trying to get Cone’s IR “right” than I have on any other aspect of the compiler.

Gradual Memory Management

Realtime, quality 3D is punishing on hardware and software alike. At least every 17 milliseconds, the scene needs to be updated and redrawn. Managing memory efficiently across the many large and small data structures that make up an interesting 3D scene is a well-known and important part of that challenge.