Fast Template-Based Code Generation for MLIR

Fast compilation is essential for JIT-compilation use cases like dynamic languages or databases as well as development productivity when compiling static languages. Template-based compilation allows fast compilation times, but in existing approaches, templates are generally handwritten, limiting flexibility and causing substantial engineering effort. In this paper, we introduce an approach based on MLIR that derives code templates for the instructions of any dialect automatically ahead-of-time. Template generation re-uses the existing compilation path present in the MLIR lowering of the instructions and thereby inherently supports code generation from different abstraction levels in a single step. Our results on compiling database queries and standard C programs show a compile-time improvement of 10–30x compared to LLVM -O0 with only moderate run-time slow-downs of 1–3x, resulting in an overall improvement of 2x in a JIT-compilation-based database setting.