feat(joinir): Phase 184 - Body-local MIR Lowering Infrastructure

Phase 184 implements the foundation for body-local variable support in update expressions, completing the three-box architecture: LoopBodyLocalEnv (storage), UpdateEnv (composition), and CarrierUpdateEmitter (emission). ## Implementation Summary ### Task 184-1: Design Document - Created phase184-body-local-mir-lowering.md - Two-Environment System design (ConditionEnv + LoopBodyLocalEnv) - Box-First design principles documented ### Task 184-2: LoopBodyLocalEnv Implementation - New file: src/mir/join_ir/lowering/loop_body_local_env.rs (216 lines) - Storage box for body-local variable name → ValueId mappings - BTreeMap for deterministic ordering (PHI consistency) - 7 unit tests: empty env, single/multiple locals, get/contains, iteration ### Task 184-3: UpdateEnv Implementation - New file: src/mir/join_ir/lowering/update_env.rs (237 lines) - Composition box for unified variable resolution - Priority order: ConditionEnv (condition vars) → LoopBodyLocalEnv (body-local) - 8 unit tests: priority, fallback, not found, combined lookup ### Task 184-4: CarrierUpdateEmitter Integration - Modified: src/mir/join_ir/lowering/carrier_update_emitter.rs - Added emit_carrier_update_with_env() (UpdateEnv version) - Kept emit_carrier_update() for backward compatibility - 4 new unit tests: body-local variable, priority, not found, const update - Total 10 tests PASS (6 existing + 4 new) ### Task 184-5: Representative Test Cases - apps/tests/phase184_body_local_update.hako (Pattern1 baseline) - apps/tests/phase184_body_local_with_break.hako (Pattern2, Phase 185 target) ### Task 184-6: Documentation Updates - Updated: docs/development/current/main/joinir-architecture-overview.md - Updated: CURRENT_TASK.md (Phase 184 completion record) ## Test Results All 25 unit tests PASS: - LoopBodyLocalEnv: 7 tests - UpdateEnv: 8 tests - CarrierUpdateEmitter: 10 tests (6 existing + 4 new) Build: ✅ Success (0 errors) ## Design Constraints Following 箱理論 (Box Theory) principles: - Single Responsibility: Each box has one clear purpose - Deterministic: BTreeMap ensures consistent ordering - Conservative: Pattern5 (Trim) integration deferred to Phase 185 - Fail-Fast: Explicit errors for unsupported patterns ## Scope Limitation Phase 184 provides the **infrastructure only**: - ✅ Storage box (LoopBodyLocalEnv) - ✅ Composition box (UpdateEnv) - ✅ Emission support (CarrierUpdateEmitter) - ❌ Pattern2/4 integration (requires body-local collection, Phase 185) ## Next Steps Phase 185: Pattern2/4 Integration - Integrate LoopBodyLocalEnv into Pattern2/4 lowerers - Add body-local variable collection from loop body AST - Enable full E2E body-local variable support in update expressions 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
2025-12-08 23:59:19 +09:00
parent 440f8646b1
commit b6e31cf8ca
9 changed files with 1263 additions and 6 deletions
--- a/docs/development/current/main/joinir-architecture-overview.md
+++ b/docs/development/current/main/joinir-architecture-overview.md
@ -169,6 +169,23 @@ JoinIR ラインで守るべきルールを先に書いておくよ：
    - else-continue を then-continue へ正規化し、Select ベースの continue を簡潔にする。
    - ループ本体で実際に更新されるキャリアだけを抽出（Pattern 4 で不要キャリアを排除）。

+- **LoopBodyLocalEnv / UpdateEnv / CarrierUpdateEmitter（Phase 184）**
+  - ファイル:
+    - `src/mir/join_ir/lowering/loop_body_local_env.rs`
+    - `src/mir/join_ir/lowering/update_env.rs`
+    - `src/mir/join_ir/lowering/carrier_update_emitter.rs`
+  - 責務:
+    - **LoopBodyLocalEnv**: ループ本体で宣言された body-local 変数の名前→ValueId マッピングを管理（箱化設計）。
+    - **UpdateEnv**: 条件変数（ConditionEnv）と body-local 変数（LoopBodyLocalEnv）を統合した変数解決層。
+      - Priority order: 1. Condition variables（高優先度） → 2. Body-local variables（フォールバック）
+    - **CarrierUpdateEmitter**: UpdateExpr を JoinIR 命令に変換する際、UpdateEnv を使用して body-local 変数をサポート。
+      - `emit_carrier_update_with_env()`: UpdateEnv 版（Phase 184 新規）
+      - `emit_carrier_update()`: ConditionEnv 版（後方互換）
+  - 設計原則:
+    - **箱理論**: 各 Box が単一責任を持ち、境界明確。
+    - **決定性**: BTreeMap 使用で一貫した順序保証（PHI 生成の決定性）。
+    - **保守的**: Pattern5 (Trim) は対象外、Phase 185 で統合予定。
+
 ### 2.3 キャリア / Exit / Boundary ライン

 - **CarrierInfo / LoopUpdateAnalyzer**
--- a/docs/development/current/main/phase184-body-local-mir-lowering.md
+++ b/docs/development/current/main/phase184-body-local-mir-lowering.md
@ -0,0 +1,374 @@
+# Phase 184: Body-local MIR Lowering Design
+
+## Status: In Progress (2025-12-08)
+
+## Overview
+
+Phase 183 completed **LoopBodyLocal role separation** (condition vs body-only).
+Phase 184 implements **body-local MIR lowering** - the ability to use body-only local variables in update expressions safely.
+
+### Problem Statement
+
+**Current limitation**:
+```nyash
+local sum = 0
+local i = 0
+loop(i < 5) {
+    local temp = i * 2  // body-local variable
+    sum = sum + temp    // ❌ ERROR: temp not found in ConditionEnv
+    i = i + 1
+}
+```
+
+**Root cause**:
+- `CarrierUpdateEmitter` only has access to `ConditionEnv`
+- `ConditionEnv` only contains condition variables (loop parameters)
+- Body-local variables (`temp`) are not in `ConditionEnv`
+- Update expression `sum = sum + temp` fails to resolve `temp`
+
+**Goal**: Enable body-local variables in update expressions while maintaining architectural clarity.
+
+## Design Solution
+
+### Architecture: Two-Environment System
+
+```
+┌─────────────────────┐
+│   ConditionEnv      │  Condition variables (loop parameters)
+│  - i → ValueId(0)   │  Priority: HIGH
+│  - end → ValueId(1) │
+└─────────────────────┘
+         ↓
+┌─────────────────────┐
+│ LoopBodyLocalEnv    │  Body-local variables
+│  - temp → ValueId(5)│  Priority: LOW (only if not in ConditionEnv)
+│  - digit → ValueId(6)│
+└─────────────────────┘
+         ↓
+┌─────────────────────┐
+│    UpdateEnv        │  Unified resolution layer
+│  resolve(name):     │  1. Try ConditionEnv first
+│    cond.get(name)   │  2. Fallback to LoopBodyLocalEnv
+│    .or(body.get())  │
+└─────────────────────┘
+```
+
+### Box-First Design
+
+Following **箱理論 (Box Theory)** principles:
+
+#### Box 1: LoopBodyLocalEnv (Storage Box)
+
+**Single Responsibility**: Collect and manage body-local variable mappings (name → ValueId).
+
+```rust
+pub struct LoopBodyLocalEnv {
+    locals: BTreeMap<String, ValueId>, // Deterministic ordering
+}
+
+impl LoopBodyLocalEnv {
+    /// Scan loop body AST and collect local definitions
+    pub fn from_loop_body(
+        body: &[ASTNode],
+        builder: &mut JoinIrBuilder
+    ) -> Self;
+
+    /// Resolve a body-local variable name to JoinIR ValueId
+    pub fn get(&self, name: &str) -> Option<ValueId>;
+}
+```
+
+**Design rationale**:
+- **BTreeMap**: Ensures deterministic iteration (PHI ordering consistency)
+- **from_loop_body()**: Separates collection logic from lowering logic
+- **get()**: Simple lookup, no side effects
+
+#### Box 2: UpdateEnv (Composition Box)
+
+**Single Responsibility**: Unified variable resolution for update expressions.
+
+```rust
+pub struct UpdateEnv<'a> {
+    condition_env: &'a ConditionEnv,      // Priority 1: Condition vars
+    body_local_env: &'a LoopBodyLocalEnv, // Priority 2: Body-local vars
+}
+
+impl<'a> UpdateEnv<'a> {
+    /// Resolve variable name with priority order
+    pub fn resolve(&self, name: &str) -> Option<ValueId> {
+        self.condition_env.get(name)
+            .or_else(|| self.body_local_env.get(name))
+    }
+}
+```
+
+**Design rationale**:
+- **Composition**: Combines two environments without owning them
+- **Priority order**: Condition variables take precedence (shadowing prevention)
+- **Lightweight**: No allocation, just references
+
+### Integration Points
+
+#### Current Flow (Pattern2 Example)
+
+```rust
+// Pattern2Lowerer::lower()
+let condition_env = /* ... */;
+
+// Emit carrier update
+let update_value = emit_carrier_update(
+    &carrier,
+    &update_expr,
+    &mut alloc_value,
+    &condition_env,  // ❌ Only has condition variables
+    &mut instructions,
+)?;
+```
+
+#### Phase 184 Flow
+
+```rust
+// Pattern2Lowerer::lower()
+let condition_env = /* ... */;
+let body_local_env = LoopBodyLocalEnv::from_loop_body(&body_nodes, builder);
+
+// Create unified environment
+let update_env = UpdateEnv {
+    condition_env: &condition_env,
+    body_local_env: &body_local_env,
+};
+
+// Emit carrier update (now with body-local support)
+let update_value = emit_carrier_update_with_env(
+    &carrier,
+    &update_expr,
+    &mut alloc_value,
+    &update_env,  // ✅ Has both condition and body-local variables
+    &mut instructions,
+)?;
+```
+
+## Scope and Constraints
+
+### In Scope (Phase 184)
+
+1. **Body-local variable collection**: `LoopBodyLocalEnv::from_loop_body()`
+2. **Unified resolution**: `UpdateEnv::resolve()`
+3. **CarrierUpdateEmitter integration**: Use `UpdateEnv` instead of `ConditionEnv`
+4. **Pattern2/4 integration**: Pass `body_local_env` to update lowering
+
+### Out of Scope
+
+1. **Condition variable usage**: Body-locals still cannot be used in conditions
+2. **Pattern5 (Trim) integration**: Defer to Phase 185
+3. **Complex expressions**: Only simple variable references in updates
+4. **Type checking**: Assume type correctness (existing type inference handles this)
+
+### Design Constraints
+
+Following **Phase 178 Fail-Fast** and **箱理論** principles:
+
+1. **Single Responsibility**: Each Box has one clear purpose
+2. **Deterministic**: BTreeMap for consistent ordering
+3. **Conservative**: No changes to Trim/Pattern5 logic
+4. **Explicit errors**: If body-local used in condition → Fail loudly
+
+## Implementation Tasks
+
+### Task 184-1: Design Document ✅ (This document)
+
+### Task 184-2: LoopBodyLocalEnv Implementation
+
+**File**: `src/mir/join_ir/lowering/loop_body_local_env.rs` (new)
+
+**Core logic**:
+```rust
+impl LoopBodyLocalEnv {
+    pub fn from_loop_body(body: &[ASTNode], builder: &mut JoinIrBuilder) -> Self {
+        let mut locals = BTreeMap::new();
+
+        for node in body {
+            if let ASTNode::LocalDecl { name, init_value } = node {
+                // Lower init_value to JoinIR
+                let value_id = builder.lower_expr(init_value)?;
+                locals.insert(name.clone(), value_id);
+            }
+        }
+
+        Self { locals }
+    }
+}
+```
+
+**Unit tests** (3-5 tests):
+- `test_empty_body`: No locals → empty env
+- `test_single_local`: One local → one mapping
+- `test_multiple_locals`: Multiple locals → sorted keys
+- `test_get_existing`: Lookup succeeds
+- `test_get_nonexistent`: Lookup returns None
+
+### Task 184-3: UpdateEnv Implementation
+
+**File**: `src/mir/join_ir/lowering/update_env.rs` (new)
+
+**Core logic**:
+```rust
+pub struct UpdateEnv<'a> {
+    condition_env: &'a ConditionEnv,
+    body_local_env: &'a LoopBodyLocalEnv,
+}
+
+impl<'a> UpdateEnv<'a> {
+    pub fn new(
+        condition_env: &'a ConditionEnv,
+        body_local_env: &'a LoopBodyLocalEnv,
+    ) -> Self {
+        Self { condition_env, body_local_env }
+    }
+
+    pub fn resolve(&self, name: &str) -> Option<ValueId> {
+        self.condition_env.get(name)
+            .or_else(|| self.body_local_env.get(name))
+    }
+}
+```
+
+**Unit tests** (2-3 tests):
+- `test_resolve_condition_priority`: Condition var found first
+- `test_resolve_body_local_fallback`: Body-local found when condition absent
+- `test_resolve_not_found`: Neither env has variable → None
+
+### Task 184-4: CarrierUpdateEmitter Integration
+
+**File**: `src/mir/join_ir/lowering/carrier_update_emitter.rs` (modify)
+
+**Changes**:
+1. Add new function variant accepting `UpdateEnv`:
+```rust
+pub fn emit_carrier_update_with_env(
+    carrier: &CarrierVar,
+    update: &UpdateExpr,
+    alloc_value: &mut dyn FnMut() -> ValueId,
+    env: &UpdateEnv,  // New: UpdateEnv instead of ConditionEnv
+    instructions: &mut Vec<JoinInst>,
+) -> Result<ValueId, String> {
+    // Use env.resolve() instead of env.get()
+}
+```
+
+2. Keep existing `emit_carrier_update()` for backward compatibility
+3. Update Pattern2/4 callers to use new variant
+
+**Validation**: Existing tests must pass (backward compatibility).
+
+### Task 184-5: Representative Tests
+
+**File**: `apps/tests/phase184_body_local_update.hako` (new)
+
+```nyash
+// Body-local used in update expression
+static box Main {
+    main() {
+        local sum = 0
+        local i = 0
+        loop(i < 5) {
+            local temp = i * 2  // Body-local variable
+            sum = sum + temp    // Use in update expression
+            i = i + 1
+        }
+        print(sum)  // Expected: 0+2+4+6+8 = 20
+    }
+}
+```
+
+**Test commands**:
+```bash
+# Structure trace
+NYASH_JOINIR_STRUCTURE_ONLY=1 ./target/release/hakorune apps/tests/phase184_body_local_update.hako
+
+# Full execution
+NYASH_JOINIR_CORE=1 ./target/release/hakorune apps/tests/phase184_body_local_update.hako
+```
+
+### Task 184-6: Documentation Updates
+
+1. **Update**: `docs/development/current/main/joinir-architecture-overview.md`
+   - Add LoopBodyLocalEnv section
+   - Update UpdateEnv integration diagram
+
+2. **Update**: `CURRENT_TASK.md`
+   - Mark Phase 184 complete
+   - Add Phase 185 preview
+
+## Validation Strategy
+
+### Success Criteria
+
+1. **Unit tests pass**: LoopBodyLocalEnv and UpdateEnv tests green
+2. **Backward compatibility**: Existing Pattern2/4 tests still pass
+3. **Representative test**: phase184_body_local_update.hako executes correctly (output: 20)
+4. **No regression**: Trim patterns (Pattern5) unaffected
+
+### Test Commands
+
+```bash
+# Unit tests
+cargo test --release --lib loop_body_local_env
+cargo test --release --lib update_env
+cargo test --release --lib carrier_update
+
+# Integration test
+NYASH_JOINIR_CORE=1 ./target/release/hakorune apps/tests/phase184_body_local_update.hako
+
+# Regression check (Trim pattern)
+NYASH_JOINIR_CORE=1 ./target/release/hakorune apps/tests/phase172_trim_while.hako
+```
+
+## Known Limitations
+
+### Not Supported (Explicit Design Decision)
+
+1. **Body-local in conditions**:
+```nyash
+loop(i < 5) {
+    local temp = i * 2
+    if (temp > 6) break  // ❌ ERROR: Body-local in condition not allowed
+}
+```
+**Reason**: Condition variables must be loop parameters (JoinIR entry signature constraint).
+
+2. **Shadowing**:
+```nyash
+loop(i < 5) {
+    local i = 10  // ❌ ERROR: Shadows condition variable
+}
+```
+**Reason**: `UpdateEnv` prioritizes condition variables - shadowing forbidden.
+
+3. **Complex expressions**:
+```nyash
+loop(i < 5) {
+    local temp = obj.method()  // ⚠️ May not work yet
+}
+```
+**Reason**: Limited to expressions `JoinIrBuilder::lower_expr()` supports.
+
+## Future Work (Phase 185+)
+
+### Phase 185: Trim Pattern Integration
+
+- Extend LoopBodyLocalEnv to handle Trim carrier variables
+- Update TrimLoopLowerer to use UpdateEnv
+
+### Phase 186: Condition Expression Support
+
+- Allow body-local variables in break/continue conditions
+- Requires inline expression evaluation in condition lowering
+
+## References
+
+- **Phase 183**: LoopBodyLocal role separation (condition vs body-only)
+- **Phase 178**: Fail-Fast error handling principles
+- **Phase 171-C**: LoopBodyCarrierPromoter original design
+- **carrier_update_emitter.rs**: Current update emission logic
+- **condition_env.rs**: Condition variable environment design