Graal IR: An Extensible Declarative Intermediate Representation

We present an intermediate representation (IR) for a Java just in time (JIT) compiler written in Java. It is a graph-based IR that models both control-flow and data-flow dependencies between nodes. We show the framework in which we developed our IR. Much care has been taken to allow the programmer to focus on compiler optimization rather than IR bookkeeping. Edges between nodes are declared concisely using Java annotations, and common properties and functions on nodes are communicated to the framework by implementing interfaces. Building upon these declarations, the graph framework automatically implements a set of useful primitives that the programmer can use to implement optimizations.