RFC-0010: JIT and AOT

Status: Draft | Version: 0.1.0

1. Modes

• Interpreter: debug, editor, cold start, dynamic experimentation.
• JIT: hot paths, runtime specialization, dynamic worlds.
• AOT: stable deployments, edge, robotics, servers.

2. Hotness

Cold -> Warm -> Hot -> VeryHot.

3. Code cache key

pub struct CodeCacheKey {
    pub module_hash: Hash,
    pub target: TargetId,
    pub profile: ProfileHash,
}

4. JIT lifecycle

Compile -> Validate -> Install -> Execute -> Profile -> Recompile/Invalidate.

5. Assumptions

Specialized code must record assumptions such as component schema, entity count range, constant values and device capabilities.

6. Deoptimization

If an assumption becomes false, execution must safely fall back to generic EIR/interpreter or another valid compiled version.

7. Reference backends

Cranelift for fast CPU JIT; LLVM for high-optimization AOT; wgpu/SPIR-V/WGSL and native GPU backends for device targets.

8. Safety

Unvalidated generated code cannot enter production execution.