Miden IR Interpreter

This crate defines a lightweight interpreter for arbitrary HIR operations, primarily intended for use in verification and tests.

It is implemented for all of the builtin dialects, but by implementing the Eval trait for operations in your dialect, they can be evaluated by the interpreter as well.

The primary interface is the HirEvaluator struct, which is provided to implementations of Eval::eval, and contains a number of primitive helpers that one can use to interact with the current state of the evaluator, e.g. read/write memory or local variables, get/set the concrete values associated with SSA registers, and more.

The evaluator works as a sort of coroutine evaluator, i.e. the core interpreter loop is managed by HirEvaluator, but the actual details of each operation are delegated to the Eval implemntation for that type. Operations interact with the evaluator for control flow by returning a ControlFlowEffect when returning from their eval implementation. The evaluator will use this to effect control transfers or other effects (e.g. traps).

For example, a Call-like operation would return ControlFlowEffect::Call, and let the evaluator perform the actual control flow, but the Call-like op itself would handle the validation and details unique to its implementation. For example, a call that needs to switch into a new interpreter context would call HirEvaluator::enter_context before returning from its eval implementation.