hakorune/mir_25_instruction_mapping.md

MIR 25-Instruction Mapping Plan

Current State: 32 Instructions → Target: 25 Instructions

Tier-0: Universal Core (8 instructions)

1. Const ✅ (already exists)
2. BinOp ✅ (already exists)
3. Compare ✅ (already exists)
4. Branch ✅ (already exists)
5. Jump ✅ (already exists)
6. Phi ✅ (already exists)
7. Call ✅ (already exists)
8. Return ✅ (already exists)

Tier-1: Nyash Semantics (12 instructions)

9. NewBox ✅ (already exists)
10. BoxFieldLoad ← RENAME from Load/RefGet
11. BoxFieldStore ← RENAME from Store/RefSet
12. BoxCall ✅ (already exists)
13. Safepoint ✅ (already exists as separate instruction)
14. RefGet → RENAME to RefGet ✅
15. RefSet → RENAME to RefSet ✅
16. WeakNew ✅ (already exists)
17. WeakLoad ✅ (already exists)
18. WeakCheck ← NEW (check weak reference validity)
19. Send ← NEW (Bus communication)
20. Recv ← NEW (Bus communication)

Tier-2: Implementation Assistance (5 instructions)

21. TailCall ← NEW (tail call optimization)
22. Adopt ← NEW (ownership transfer)
23. Release ← NEW (ownership release)
24. MemCopy ← NEW (optimized memory operations)
25. AtomicFence ← RENAME from BarrierRead/BarrierWrite

Instructions to Remove/Consolidate (7 instructions)

• UnaryOp → Merge into BinOp or eliminate
• Load → Consolidate into BoxFieldLoad
• Store → Consolidate into BoxFieldStore
• ArrayGet → Use BoxFieldLoad with array indexing
• ArraySet → Use BoxFieldStore with array indexing
• Cast → Eliminate or merge into BinOp
• Copy → Eliminate (optimization-specific)
• Debug → Remove from MIR (keep as separate system)
• Print → Use Call with print function
• Throw → Use Call with exception function
• Catch → Use Call with catch handler
• RefNew → Eliminate (use NewBox)
• TypeCheck → Use Compare with type introspection
• BarrierRead/BarrierWrite → Consolidate into AtomicFence
• FutureNew/FutureSet/Await → Use BoxCall with Future methods

Effect System Mapping

Current → New Effect Categories

• Pure: Const, BinOp, Compare, Phi, RefGet, WeakNew, WeakLoad, WeakCheck
• Mut: BoxFieldStore, RefSet, Adopt, Release, MemCopy
• Io: Send, Recv, Safepoint, AtomicFence
• Control: Branch, Jump, Return, TailCall
• Context-dependent: Call, BoxCall

Implementation Strategy

Phase 1: Core Instruction Consolidation

1. Rename Load → BoxFieldLoad
2. Rename Store → BoxFieldStore
3. Remove eliminated instructions
4. Add missing new instructions

Phase 2: Effect System Update

1. Update effect classification to 4 categories
2. Update all instruction effect mappings
3. Implement effect-based optimization rules

Phase 3: Backend Updates

1. Update Interpreter backend
2. Update VM backend
3. Update WASM backend
4. Ensure all support exactly 25 instructions

Phase 4: Verification System

1. Implement ownership forest verification
2. Add strong cycle detection
3. Add weak reference safety checks
4. Implement RefSet ownership validation