RFC-0003: Execution IR

Status: Draft | Version: 0.1.0

1. Purpose

EIR is the common executable representation for interpreter, JIT and AOT.

2. Structure

pub struct Module {
    pub functions: Vec<Function>,
    pub globals: Vec<Global>,
    pub resources: Vec<Resource>,
}
pub struct Function {
    pub id: FunctionId,
    pub signature: Signature,
    pub blocks: Vec<Block>,
}
pub struct Block {
    pub id: BlockId,
    pub args: Vec<Value>,
    pub operations: Vec<Operation>,
    pub terminator: Terminator,
}

EIR uses SSA-like values.

3. Operations

Scalar: Load, Store, Add, Sub, Mul, Div, FMA, Compare, Select, Cast, Call. Vector: VecLoad, VecStore, Shuffle, Reduce. Memory: Alloc, Free, Copy, Prefetch. Parallel: ParallelFor, Map, Reduce, Scan, Pipeline, Barrier. Device: Dispatch, Copy, Fence. Distributed: RemoteCall, RemoteData, Migration, Replication.

Domain operations may exist temporarily but must lower to base EIR before production code generation.

4. Memory spaces

ReadOnly, ReadWrite, Atomic, Shared, GPU.

5. Determinism

Operations that participate in deterministic execution must declare deterministic semantics; unordered floating-point reductions are forbidden in strict deterministic mode.

6. Validation

SSA dominance, type correctness, memory-space legality, dependency correctness, bounded resource use, and capability requirements must be validated before execution.

7. Invariant

The same valid EIR must have semantically equivalent interpreter, JIT and AOT execution.