Threaded Code Generation with a Meta-Tracing JIT Compiler

TL;DR

This paper introduces a method to generate threaded code within a meta-tracing JIT compiler framework, significantly reducing code size and compilation time while improving execution speed, without major modifications to existing systems.

Contribution

It presents a novel approach to generate threaded code using an existing meta-tracing JIT, enabling efficient multitier JIT support with minimal changes to RPython.

Findings

Code size reduced by 80%

Compilation time decreased by 60%

Execution ran 7% faster than interpreter-only

Abstract

Language implementation frameworks, e.g., RPython and Truffle/Graal, are practical tools for creating efficient virtual machines, including a well-functioning just-in-time (JIT) compiler. It is demanding to support multitier JIT compilation in such a framework for language developers. This paper presents an idea to generate threaded code by reusing an existing meta-tracing JIT compiler, as well as an interpreter design for it. Our approach does not largely modify RPython itself but constructs an effective interpreter definition to enable threaded code generation in RPython. We expect our system to be extended to support multilevel JIT compilation in the RPython framework. We measured the potential performance of our threaded code generation by simulating its behavior in PyPy. We confirmed that our approach reduced code sizes by 80 \% and compilation times by 60 \% compared to PyPy's JIT compiler on average, and ran about 7 \% faster than the interpreter-only execution.