docs/ci: selfhost bootstrap/exe-first workflows; add ny-llvmc scaffolding + JSON v0 schema validation; plan: unify to Nyash ABI v2 (no backwards compat)

.github/workflows/selfhost-bootstrap.yml

@@ -0,0 +1,50 @@
+name: Selfhost Bootstrap Smoke
+
+on:
+  push:
+    paths:
+      - 'src/**'
+      - 'apps/**'
+      - 'tools/**'
+      - 'docs/**'
+      - 'Cargo.toml'
+      - 'Cargo.lock'
+      - '.github/workflows/selfhost-bootstrap.yml'
+  pull_request:
+    paths:
+      - 'src/**'
+      - 'apps/**'
+      - 'tools/**'
+      - 'docs/**'
+
+jobs:
+  selfhost-bootstrap:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    env:
+      CARGO_TERM_COLOR: always
+      NYASH_DISABLE_PLUGINS: '1'
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Rust (stable)
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Cache cargo registry and build
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-cargo-
+
+      - name: Build (release, cranelift-jit)
+        run: cargo build --release --features cranelift-jit -j 2
+
+      - name: Run bootstrap selfhost smoke
+        run: timeout -s KILL 40s bash tools/bootstrap_selfhost_smoke.sh
+

.github/workflows/selfhost-exe-first.yml

@@ -0,0 +1,57 @@
+name: Selfhost EXE-first (Optional)
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '0 7 * * *'
+
+jobs:
+  selfhost-exe-first:
+    runs-on: ubuntu-latest
+    timeout-minutes: 25
+    env:
+      CARGO_TERM_COLOR: always
+      NYASH_DISABLE_PLUGINS: '1'
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Rust (stable)
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Cache cargo registry and build
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-cargo-
+
+      - name: Install LLVM 18 (llvm-config-18)
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y curl ca-certificates lsb-release wget gnupg python3-pip
+          curl -fsSL https://apt.llvm.org/llvm.sh -o llvm.sh
+          chmod +x llvm.sh
+          sudo ./llvm.sh 18
+          llvm-config-18 --version
+
+      - name: Install llvmlite (Python)
+        run: |
+          python3 -m pip install --upgrade pip
+          python3 -m pip install llvmlite jsonschema
+
+      - name: Build nyash (release)
+        run: cargo build --release -j 2
+
+      - name: ny-llvmc dummy smoke
+        run: |
+          cargo build --release -p nyash-llvm-compiler -j 2
+          ./target/release/ny-llvmc --dummy --out /tmp/dummy.o
+          file /tmp/dummy.o || true
+
+      - name: Run EXE-first smoke (parser EXE + bridge)
+        run: timeout -s KILL 10m bash tools/exe_first_smoke.sh

CURRENT_TASK.md

@@ -3,6 +3,7 @@
 Summary
 - Default execution is MIR13 (PHI‑off). Bridge/Builder do not emit PHIs; llvmlite synthesizes PHIs when needed. MIR14 (PHI‑on) remains experimental for targeted tests.
 - PyVM is the semantic reference engine; llvmlite is used for AOT and parity checks.
+ - GC: user modes defined; controller実装（rc+cycle skeleton + metrics/diagnostics）に移行。LLVM safepoint輸出/NyRT配線と自動挿入（envゲートON）を完了。
 
 What Changed (recent)
 - MIR13 default enabled
@@ -16,30 +17,56 @@ What Changed (recent)
   - Selfhost/PyVM スモークを通して E2E 確認（peek/ternary）。
 - llvmlite stability for MIR13（bring‑up進行中）
   - Control‑flow 分離: `instructions/controlflow/{branch,jump,while_.py}` を導入し、`llvm_builder.py` の責務を縮小。
-  - プリパス導入（環境変数で有効化）: `NYASH_LLVM_PREPASS_LOOP=1`
+  - プリパス（環境変数で有効化）: `NYASH_LLVM_PREPASS_LOOP=1`, `NYASH_LLVM_PREPASS_IFMERGE=1`
     - ループ検出（単純 while 形）→ 構造化 lower（LoopForm失敗時は regular while）
-    - CFG ユーティリティ: `cfg/utils.py`（preds/succs）
-  - 値解決ポリシー共通化: `utils/values.py`（prefer same‑block SSA → resolver）
-  - vmap の per‑block 化: `lower_block` 内で `vmap_cur` を用意し、ブロック末に `block_end_values` へスナップショット。cross‑block 汚染を抑制。
-  - Resolver 強化: end‑of‑block解決で他ブロックのPHIを安易に採用しない（自己参照/非支配回避）。
+    - if‑merge（ret‑merge）前処理: ret 値 PHI の前宣言と finalize 配線の一意化
+    - CFG ユーティリティ: `src/llvm_py/cfg/utils.py`（preds/succs）
+  - PHI 配線の分離: `src/llvm_py/phi_wiring.py` に placeholder/finalize を移管（builder 薄化）
+  - 値解決ポリシー共通化: `src/llvm_py/utils/values.py`（prefer same‑block SSA → resolver）
+  - vmap の per‑block 化: `vmap_cur` を用意し、ブロック末に `block_end_values` へスナップショット。cross‑block 汚染を抑制。
+  - Resolver 強化: end‑of‑block 解決で他ブロック PHI を安易に採用しない（自己参照/非支配を回避）。
+  - BuildCtx 導入: `src/llvm_py/build_ctx.py` で lowering 引数を集約（compare/ret/call/boxcall/externcall/typeop/newbox/safepoint が ctx 対応）
+  - トレース統一: `src/llvm_py/trace.py` を追加し、`NYASH_CLI_VERBOSE`/`NYASH_LLVM_TRACE_PHI`/`NYASH_LLVM_TRACE_VALUES` を一元管理
+  - curated スモーク拡張: `tools/smokes/curated_llvm.sh --with-if-merge` を追加（if‑merge ケース含む）
 - Parity runner pragmatics
   - `tools/pyvm_vs_llvmlite.sh` compares exit code by default; use `CMP_STRICT=1` for stdout+exit.
   - Stage‑2 smokes更新: `tools/selfhost_stage2_smoke.sh` に "Peek basic" を追加。
+- GC controller/metrics（Phase‑15）
+  - `GcController`（統合フック）導入＋CLI `--gc`（`NYASH_GC_MODE`）。CountingGcは互換ラッパに縮退。
+  - NyRT exports: `ny_safepoint` / `ny_check_safepoint` / `nyash.gc.barrier_write` → runtime hooks 連携。
+  - LLVM：自動 safepoint 挿入（loop header / call / externcall / boxcall）。`NYASH_LLVM_AUTO_SAFEPOINT` で制御（既定=1）。
+  - メトリクス：text/JSON（`NYASH_GC_METRICS{,_JSON}=1`）。JSONに alloc_count/alloc_bytes/trial_nodes/edges/collections/last_ms/reason_bits/thresholds を含む。
+  - 診断：`NYASH_GC_LEAK_DIAG=1` でハンドルTop‑K（残存）出力。Array/Map 到達集合の試走（gc_trace）。
+
+- CI/DevOps（Self‑Hosting パイロット強化）
+  - 追加: `.github/workflows/selfhost-bootstrap.yml`（常時） — `tools/bootstrap_selfhost_smoke.sh` を40s timeoutで実行。
+  - 追加: `.github/workflows/selfhost-exe-first.yml`（任意/cron） — LLVM18 + llvmlite をセットアップし `tools/exe_first_smoke.sh` を実行。
+  - スモーク堅牢化: `tools/bootstrap_selfhost_smoke.sh`/`tools/exe_first_smoke.sh` に timeout を付与。
+  - JSON v0 スキーマ追加: `docs/reference/mir/json_v0.schema.json` と検証ツール `tools/validate_mir_json.py`。EXE‑first スモークに組み込み。
+
+- LLVM crate 分離の足場（Phase‑15.6 向け）
+  - 新規クレート（スキャフォールド）: `crates/nyash-llvm-compiler`（CLI名: `ny-llvmc`）。
+    - `--dummy --out <o>` でダミー `.o` を生成。
+    - `--in <mir.json|-> --out <o>` で MIR(JSON)→`.o` を llvmlite ハーネス経由で生成（`tools/llvmlite_harness.py`）。
+  - ドキュメント追記: `docs/LLVM_HARNESS.md` に `ny-llvmc` とスキーマ検証の項を追加。
+
+- Nyash ABI v2（TypeBox）検出の足場
+  - ローダに `nyash_typebox_<Box>` シンボル検出を追加（`abi_tag='TYBX'`/`version`/`invoke_id`）し、Boxスペックへ保持（まだ実行には未使用）。
 
 Current Status
 - Self‑hosting Bridge → PyVM smokes: PASS（Stage‑2 代表: array/string/logic/if/loop/ternary/peek/dot-chain）
 - PyVM core fixes applied: compare(None,x) の安全化、Copy 命令サポート、最大ステップ上限（NYASH_PYVM_MAX_STEPS）
 - MIR13（PHI‑off）: if/ternary/loop の合流で Copy が正しく JSON に出るよう修正（emit_mir_json + builder no‑phi 合流）
 - Curated LLVM（PHI‑off 既定）: 継続（個別ケースの IR 生成不備は未着手）
-- LLVM ハーネス（llvmlite）:
+LLVM ハーネス（llvmlite/AOT）:
   - `loop_if_phi`: プリパスON＋構造化whileで EXE 退出コード 0（緑）。
-  - `ternary_nested`: vmap per‑block で安定度向上。残タスク: merge(ret) の PHI 配線をプリパス/resolve 側で確定・重複排除。
+  - `ternary_nested`: if‑merge プリパス＋phi_wiring で ret‑merge を構造化し、退出コード一致（緑）。
 
 Next (short plan)
 0) Refactor/Structure（継続）
-   - controlflow の切出し完了（branch/jump/while）。binop/compare/copy の前処理を `utils/values.resolve_i64_strict` に集約（完了）。
-   - vmap per‑block 化（完了）。builder の責務縮小と prepass/cfg/util への移譲（進行中）。
-   - if‑merge プリパス実装: ret‑merge の構造化/PHI確定（予定）。
+   - BuildCtx 展開を完了（barrier/atomic/loopform も ctx 主経路に）
+   - trace 化の残り掃除（環境直読み print を削減）
+   - phi_wiring を関数分割（解析/配線/タグ付け）→ ユニットテスト追加
 1) Legacy Interpreter/VM offboarding (phase‑A):
    - ✅ Introduced `vm-legacy` feature (default OFF) to gate old VM execution層。
    - ✅ 抽出: JIT が参照する最小型（例: `VMValue`）を薄い共通モジュールへ切替（`vm_types`）。
@@ -50,23 +77,48 @@ Next (short plan)
 2) Legacy Interpreter/VM offboarding (phase‑B):
    - 物理移動: `src/archive/{interpreter_legacy,vm_legacy}/` へ移設（ドキュメント更新）。
 3) LLVM/llvmlite 整備（優先中）:
-   - MIR13 の Copy 合流を LLVM IR に等価反映（pred‑localize or PHI 合成）: per‑block vmap 完了、resolver 強化済。
+   - MIR13 の Copy 合流を LLVM IR に等価反映（pred‑localize or PHI 合成）: per‑block vmap 完了、resolver/phi_wiring 強化済。
    - 代表ケース:
      - `apps/tests/loop_if_phi.nyash`: プリパスONで緑（退出コード一致）。
-     - `apps/tests/ternary_nested.nyash`: if‑merge プリパスでの構造化/PHI 確定を実装 → IR 検証通過・退出コード一致まで。
+     - `apps/tests/ternary_nested.nyash`: if‑merge + phi_wiring で退出コード一致を継続。
    - `tools/pyvm_vs_llvmlite.sh` で PyVM と EXE の退出コード一致（必要に応じて CMP_STRICT=1）。
 4) PHI‑on lane（任意）: `loop_if_phi` 支配関係を finalize/resolve の順序強化で観察（低優先）。
 5) Runner refactor（小PR）:
    - `selfhost/{child.rs,json.rs}` 分離; `modes/common/{io,resolve,exec}.rs` 分割; `runner/mod.rs`の表面削減。
 6) Optimizer/Verifier thin‑hub cleanup（非機能）: orchestrator最小化とパス境界の明確化。
+7) GC（controller）観測の磨き込み
+   - JSON: running averages / roots要約（任意） / 理由タグ拡張
+   - 収集頻度のサンプリング支援
+   - plugin/FFI は非移動のまま、ハンドル間接を継続
+8) LLVM crate split（EXE‑first）
+   - LLVM harness/builder を `nyash-llvm-compiler` crate と CLI（`ny-llvmc`）に分離（入力: MIR JSON v0 / 出力: .o/.exe）
+   - `tools/build_llvm.sh` 内部を新crate APIに寄せ、Runnerからも呼べるよう段階移行
+   - CI: selfhost smokes と LLVM EXE smokes を分離しアーティファクト配布線を評価
+
+9) Nyash ABI v2 統一（後方互換なし）
+   - 方針: 既存 Type‑C ABI（library‑level `nyash_plugin_invoke`）を撤退し、Box単位の TypeBox へ一本化。
+   - ローダ: `nyash_typebox_<Box>` の `invoke_id(instance_id, method_id, ...)` を実行ポインタとして保持し、birth/fini も含めて統一。
+   - プラグイン: 公式プラグイン（String/File/Array/Map/Console/Integer）を順次 v2 へ移行。`resolve(name)->method_id` 実装。
+   - 仕様: エラー規約（OK/E_SHORT/E_ARGS/E_TYPE/E_METHOD/E_HANDLE/E_PLUGIN）・TLVタグ一覧を docs に凍結、Cヘッダ雛形（`nyash_abi.h`）を配布。
+   - CI: v2専用スモークを常時化（Linux）。Windows/macOS は任意ジョブで追随。
 
 How to Run
 - PyVM reference smokes: `tools/pyvm_stage2_smoke.sh`
 - Bridge → PyVM smokes: `tools/selfhost_stage2_bridge_smoke.sh`
 - LLVM curated (PHI‑off default): `tools/smokes/curated_llvm.sh`
 - LLVM PHI‑on (experimental): `tools/smokes/curated_llvm.sh --phi-on`
+- LLVM curated with if‑merge prepass: `tools/smokes/curated_llvm.sh --with-if-merge`
 - Parity (AOT vs PyVM): `tools/pyvm_vs_llvmlite.sh <file.nyash>` (`CMP_STRICT=1` to enable stdout check)
   - 開発時の補助: `NYASH_LLVM_PREPASS_LOOP=1` を併用（loop/if‑merge のプリパス有効化）。
+ - GC modes/metrics: see `docs/reference/runtime/gc.md`（`--gc` / 自動 safepoint / 収集トリガ / JSONメトリクス）
+
+Self‑Hosting CI
+- Bootstrap（常時）: `.github/workflows/selfhost-bootstrap.yml`
+- EXE‑first（任意）: `.github/workflows/selfhost-exe-first.yml`
+
+LLVM Crate（試用）
+- ダミー: `cargo build -p nyash-llvm-compiler --release && ./target/release/ny-llvmc --dummy --out /tmp/dummy.o`
+- JSON→.o: `./target/release/ny-llvmc --in mir.json --out out.o`
 
 Operational Notes
 - 環境変数
@@ -93,9 +145,13 @@ Key Flags
 - `NYASH_VERIFY_ALLOW_NO_PHI` (default 1): relax verifier for PHI‑less MIR.
 - `NYASH_LLVM_USE_HARNESS=1`: route AOT through llvmlite harness.
 - `NYASH_LLVM_TRACE_PHI=1`: trace PHI resolution/wiring.
+- `NYASH_LLVM_PREPASS_LOOP=1`: enable loop prepass (while detection/structure)
+- `NYASH_LLVM_PREPASS_IFMERGE=1`: enable if‑merge (ret‑merge) prepass
+- `NYASH_LLVM_TRACE_VALUES=1`: trace value resolution path
 
 Notes / Policies
 - Focus is self‑hosting stability. JIT/Cranelift is out of scope (safety fixes only).
 - PHI generation remains centralized in llvmlite; Bridge/Builder keep PHI‑off by default.
-- No full tracing GC yet; handles/Arc lifetimes govern object retention. Safepoint/barrier/roots are staging utilities.
+- No full tracing/moving GC yet; handles/Arc lifetimes govern object retention. Safepoint/barrier/roots are staging utilities.
+ - GC mode UX: keep user‑facing modes minimal (rc+cycle, minorgen); advanced modes are opt‑in for language dev.
  - Legacy Interpreter/VM は段階的にアーカイブへ。日常の意味論確認は PyVM を基準として継続。

crates/nyash-llvm-compiler/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "nyash-llvm-compiler"
+version = "0.1.0"
+edition = "2021"
+description = "Nyash LLVM compiler CLI (harness wrapper). Compiles MIR(JSON) -> object (.o) or dummy."
+
+[dependencies]
+anyhow = "1.0"
+clap = { version = "4.5", features = ["derive"] }
+serde_json = "1.0"
+

crates/nyash-llvm-compiler/src/main.rs

@@ -0,0 +1,122 @@
+use std::fs::File;
+use std::io::{Read, Write};
+use std::path::{Path, PathBuf};
+use std::process::Command;
+
+use anyhow::{bail, Context, Result};
+use clap::{ArgAction, Parser};
+
+#[derive(Parser, Debug)]
+#[command(name = "ny-llvmc", about = "Nyash LLVM compiler (llvmlite harness wrapper)")]
+struct Args {
+    /// MIR JSON input file path (use '-' to read from stdin). When omitted with --dummy, a dummy ny_main is emitted.
+    #[arg(long = "in", value_name = "FILE", default_value = "-")]
+    infile: String,
+
+    /// Output object file (.o)
+    #[arg(long, value_name = "FILE")]
+    out: PathBuf,
+
+    /// Generate a dummy object (ny_main -> i32 0). Ignores --in when set.
+    #[arg(long, action = ArgAction::SetTrue)]
+    dummy: bool,
+
+    /// Path to Python harness script (defaults to tools/llvmlite_harness.py in CWD)
+    #[arg(long, value_name = "FILE")]
+    harness: Option<PathBuf>,
+}
+
+fn main() -> Result<()> {
+    let args = Args::parse();
+
+    // Ensure parent dir exists
+    if let Some(parent) = args.out.parent() {
+        std::fs::create_dir_all(parent).ok();
+    }
+
+    // Resolve harness path
+    let harness_path = if let Some(p) = args.harness.clone() {
+        p
+    } else {
+        PathBuf::from("tools/llvmlite_harness.py")
+    };
+
+    if args.dummy {
+        run_harness_dummy(&harness_path, &args.out)
+            .with_context(|| "failed to run harness in dummy mode")?;
+        println!("[ny-llvmc] dummy object written: {}", args.out.display());
+        return Ok(());
+    }
+
+    // Prepare input JSON path: either from file or stdin -> temp file
+    let mut temp_path: Option<PathBuf> = None;
+    let input_path = if args.infile == "-" {
+        let mut buf = String::new();
+        std::io::stdin()
+            .read_to_string(&mut buf)
+            .context("reading MIR JSON from stdin")?;
+        // Basic sanity check that it's JSON
+        let _: serde_json::Value = serde_json::from_str(&buf)
+            .context("stdin does not contain valid JSON")?;
+        let tmp = std::env::temp_dir().join("ny_llvmc_stdin.json");
+        let mut f = File::create(&tmp).context("create temp json file")?;
+        f.write_all(buf.as_bytes()).context("write temp json")?;
+        temp_path = Some(tmp.clone());
+        tmp
+    } else {
+        PathBuf::from(&args.infile)
+    };
+
+    if !input_path.exists() {
+        bail!("input JSON not found: {}", input_path.display());
+    }
+
+    run_harness_in(&harness_path, &input_path, &args.out)
+        .with_context(|| format!("failed to compile MIR JSON via harness: {}", input_path.display()))?;
+    println!("[ny-llvmc] object written: {}", args.out.display());
+
+    // Cleanup temp file if used
+    if let Some(p) = temp_path {
+        let _ = std::fs::remove_file(p);
+    }
+
+    Ok(())
+}
+
+fn run_harness_dummy(harness: &Path, out: &Path) -> Result<()> {
+    ensure_python()?;
+    let status = Command::new("python3")
+        .arg(harness)
+        .arg("--out")
+        .arg(out)
+        .status()
+        .context("failed to execute python harness (dummy)")?;
+    if !status.success() {
+        bail!("harness exited with status: {:?}", status.code());
+    }
+    Ok(())
+}
+
+fn run_harness_in(harness: &Path, input: &Path, out: &Path) -> Result<()> {
+    ensure_python()?;
+    let status = Command::new("python3")
+        .arg(harness)
+        .arg("--in")
+        .arg(input)
+        .arg("--out")
+        .arg(out)
+        .status()
+        .context("failed to execute python harness")?;
+    if !status.success() {
+        bail!("harness exited with status: {:?}", status.code());
+    }
+    Ok(())
+}
+
+fn ensure_python() -> Result<()> {
+    match Command::new("python3").arg("--version").output() {
+        Ok(out) if out.status.success() => Ok(()),
+        _ => bail!("python3 not found in PATH (required for llvmlite harness)"),
+    }
+}
+

crates/nyrt/src/lib.rs

@@ -78,6 +78,7 @@ pub extern "C" fn nyash_string_concat_hh_export(a_h: i64, b_h: i64) -> i64 {
         String::new()
     };
     let s = format!("{}{}", to_s(a_h), to_s(b_h));
+    nyash_rust::runtime::global_hooks::gc_alloc(s.len() as u64);
     let arc: std::sync::Arc<dyn NyashBox> = std::sync::Arc::new(StringBox::new(s));
     let h = handles::to_handle(arc) as i64;
     eprintln!("[TRACE] concat_hh -> {}", h);
@@ -134,6 +135,7 @@ pub extern "C" fn nyash_string_substring_hii_export(h: i64, start: i64, end: i64
     let (st_u, en_u) = (st as usize, en as usize);
     let sub = s.get(st_u.min(s.len())..en_u.min(s.len())).unwrap_or("");
     let arc: std::sync::Arc<dyn NyashBox> = std::sync::Arc::new(StringBox::new(sub.to_string()));
+    nyash_rust::runtime::global_hooks::gc_alloc(sub.len() as u64);
     let nh = handles::to_handle(arc) as i64;
     eprintln!("[TRACE] substring_hii -> {}", nh);
     nh
@@ -196,7 +198,8 @@ pub extern "C" fn nyash_box_from_i8_string(ptr: *const i8) -> i64 {
         Ok(v) => v.to_string(),
         Err(_) => return 0,
     };
-    let arc: std::sync::Arc<dyn NyashBox> = std::sync::Arc::new(StringBox::new(s));
+    let arc: std::sync::Arc<dyn NyashBox> = std::sync::Arc::new(StringBox::new(s.clone()));
+    nyash_rust::runtime::global_hooks::gc_alloc(s.len() as u64);
     let h = handles::to_handle(arc) as i64;
     eprintln!("[TRACE] from_i8_string -> {}", h);
     h
@@ -208,6 +211,7 @@ pub extern "C" fn nyash_box_from_i8_string(ptr: *const i8) -> i64 {
 pub extern "C" fn nyash_box_from_f64(val: f64) -> i64 {
     use nyash_rust::{box_trait::NyashBox, boxes::FloatBox, jit::rt::handles};
     let arc: std::sync::Arc<dyn NyashBox> = std::sync::Arc::new(FloatBox::new(val));
+    nyash_rust::runtime::global_hooks::gc_alloc(8);
     handles::to_handle(arc) as i64
 }
 
@@ -220,6 +224,7 @@ pub extern "C" fn nyash_box_from_i64(val: i64) -> i64 {
         jit::rt::handles,
     };
     let arc: std::sync::Arc<dyn NyashBox> = std::sync::Arc::new(IntegerBox::new(val));
+    nyash_rust::runtime::global_hooks::gc_alloc(8);
     handles::to_handle(arc) as i64
 }
 
@@ -487,7 +492,8 @@ pub extern "C" fn nyash_string_from_u64x2_export(lo: i64, hi: i64, len: i64) ->
         bytes.push(((hi_u >> (8 * i)) & 0xff) as u8);
     }
     let s = String::from_utf8_lossy(&bytes).to_string();
-    let arc: std::sync::Arc<dyn NyashBox> = std::sync::Arc::new(StringBox::new(s));
+    let arc: std::sync::Arc<dyn NyashBox> = std::sync::Arc::new(StringBox::new(s.clone()));
+    nyash_rust::runtime::global_hooks::gc_alloc(s.len() as u64);
     handles::to_handle(arc) as i64
 }
 
@@ -542,9 +548,25 @@ pub extern "C" fn nyash_gc_barrier_write_export(handle_or_ptr: i64) -> i64 {
     if std::env::var("NYASH_GC_BARRIER_TRACE").ok().as_deref() == Some("1") {
         eprintln!("[nyrt] nyash.gc.barrier_write h=0x{:x}", handle_or_ptr);
     }
+    // Forward to runtime GC hooks when available (Write barrier)
+    nyash_rust::runtime::global_hooks::gc_barrier(nyash_rust::runtime::BarrierKind::Write);
     0
 }
 
+// LLVM safepoint exports (llvmlite harness)
+// export: ny_safepoint(live_count: i64, live_values: i64*) -> void
+#[no_mangle]
+pub extern "C" fn ny_safepoint(_live_count: i64, _live_values: *const i64) {
+    // For now we ignore live-values; runtime uses cooperative safepoint + poll
+    nyash_rust::runtime::global_hooks::safepoint_and_poll();
+}
+
+// export: ny_check_safepoint() -> void
+#[no_mangle]
+pub extern "C" fn ny_check_safepoint() {
+    nyash_rust::runtime::global_hooks::safepoint_and_poll();
+}
+
 #[export_name = "nyash.string.birth_h"]
 pub extern "C" fn nyash_string_birth_h_export() -> i64 {
     // Create a new StringBox via unified plugin host; return runtime handle as i64
@@ -552,6 +574,7 @@ pub extern "C" fn nyash_string_birth_h_export() -> i64 {
         if let Ok(b) = host_g.create_box("StringBox", &[]) {
             let arc: std::sync::Arc<dyn nyash_rust::box_trait::NyashBox> = std::sync::Arc::from(b);
             let h = nyash_rust::jit::rt::handles::to_handle(arc);
+            nyash_rust::runtime::global_hooks::gc_alloc(0);
             return h as i64;
         }
     }
@@ -564,6 +587,7 @@ pub extern "C" fn nyash_integer_birth_h_export() -> i64 {
         if let Ok(b) = host_g.create_box("IntegerBox", &[]) {
             let arc: std::sync::Arc<dyn nyash_rust::box_trait::NyashBox> = std::sync::Arc::from(b);
             let h = nyash_rust::jit::rt::handles::to_handle(arc);
+            nyash_rust::runtime::global_hooks::gc_alloc(0);
             return h as i64;
         }
     }
@@ -576,6 +600,7 @@ pub extern "C" fn nyash_console_birth_h_export() -> i64 {
         if let Ok(b) = host_g.create_box("ConsoleBox", &[]) {
             let arc: std::sync::Arc<dyn nyash_rust::box_trait::NyashBox> = std::sync::Arc::from(b);
             let h = nyash_rust::jit::rt::handles::to_handle(arc);
+            nyash_rust::runtime::global_hooks::gc_alloc(0);
             return h as i64;
         }
     }
@@ -587,6 +612,7 @@ pub extern "C" fn nyash_console_birth_h_export() -> i64 {
 pub extern "C" fn nyash_array_birth_h_export() -> i64 {
     let arc: std::sync::Arc<dyn nyash_rust::box_trait::NyashBox> =
         std::sync::Arc::new(nyash_rust::boxes::array::ArrayBox::new());
+    nyash_rust::runtime::global_hooks::gc_alloc(0);
     nyash_rust::jit::rt::handles::to_handle(arc) as i64
 }
 
@@ -595,6 +621,7 @@ pub extern "C" fn nyash_array_birth_h_export() -> i64 {
 pub extern "C" fn nyash_map_birth_h_export() -> i64 {
     let arc: std::sync::Arc<dyn nyash_rust::box_trait::NyashBox> =
         std::sync::Arc::new(nyash_rust::boxes::map_box::MapBox::new());
+    nyash_rust::runtime::global_hooks::gc_alloc(0);
     nyash_rust::jit::rt::handles::to_handle(arc) as i64
 }
 // ---- Process entry (driver) ----
@@ -646,6 +673,15 @@ pub extern "C" fn main() -> i32 {
             }
         }
     }
+    // Initialize a minimal runtime to back global hooks (GC/scheduler) for safepoints
+    // Choose GC hooks based on env (default dev: Counting for observability unless explicitly off)
+    let mut rt_builder = nyash_rust::runtime::NyashRuntimeBuilder::new();
+    let gc_mode = nyash_rust::runtime::gc_mode::GcMode::from_env();
+    let controller = std::sync::Arc::new(nyash_rust::runtime::gc_controller::GcController::new(gc_mode));
+    rt_builder = rt_builder.with_gc_hooks(controller);
+    let rt_hooks = rt_builder.build();
+    nyash_rust::runtime::global_hooks::set_from_runtime(&rt_hooks);
+
     let mut inited = false;
     if let Some(dir) = &exe_dir {
         let candidate = dir.join("nyash.toml");
@@ -680,6 +716,70 @@ pub extern "C" fn main() -> i32 {
         let v = ny_main();
         // Print standardized result line for golden comparisons
         println!("Result: {}", v);
+        // Optional GC metrics after program completes
+        let want_json = std::env::var("NYASH_GC_METRICS_JSON").ok().as_deref() == Some("1");
+        let want_text = std::env::var("NYASH_GC_METRICS").ok().as_deref() == Some("1");
+        if want_json || want_text {
+            let (sp, br, bw) = rt_hooks
+                .gc
+                .snapshot_counters()
+                .unwrap_or((0, 0, 0));
+            let handles = nyash_rust::jit::rt::handles::len();
+            let gc_mode_s = gc_mode.as_str();
+            // Include allocation totals if controller is used
+            let any_gc: &dyn std::any::Any = &*rt_hooks.gc;
+            let (alloc_count, alloc_bytes, trial_nodes, trial_edges, collect_total, collect_sp, collect_alloc, last_ms, last_reason) = if let Some(ctrl) = any_gc
+                .downcast_ref::<nyash_rust::runtime::gc_controller::GcController>()
+            {
+                let (ac, ab) = ctrl.alloc_totals();
+                let (tn, te) = ctrl.trial_reachability_last();
+                let (ct, csp, calloc) = ctrl.collection_totals();
+                let lms = ctrl.trial_duration_last_ms();
+                let lrf = ctrl.trial_reason_last_bits();
+                (ac, ab, tn, te, ct, csp, calloc, lms, lrf)
+            } else {
+                (0, 0, 0, 0, 0, 0, 0, 0, 0)
+            };
+            // Settings snapshot (env)
+            let sp_interval = std::env::var("NYASH_GC_COLLECT_SP").ok().and_then(|s| s.parse::<u64>().ok()).unwrap_or(0);
+            let alloc_thresh = std::env::var("NYASH_GC_COLLECT_ALLOC").ok().and_then(|s| s.parse::<u64>().ok()).unwrap_or(0);
+            let auto_sp = std::env::var("NYASH_LLVM_AUTO_SAFEPOINT").ok().map(|v| v == "1").unwrap_or(true);
+            if want_json {
+                // Minimal JSON assembly to avoid extra deps in nyrt
+                println!(
+                    "{{\"kind\":\"gc_metrics\",\"safepoints\":{},\"barrier_reads\":{},\"barrier_writes\":{},\"jit_handles\":{},\"alloc_count\":{},\"alloc_bytes\":{},\"trial_nodes\":{},\"trial_edges\":{},\"collections\":{},\"collect_by_sp\":{},\"collect_by_alloc\":{},\"last_collect_ms\":{},\"last_reason_bits\":{},\"sp_interval\":{},\"alloc_threshold\":{},\"auto_safepoint\":{},\"gc_mode\":\"{}\"}}",
+                    sp, br, bw, handles, alloc_count, alloc_bytes, trial_nodes, trial_edges, collect_total, collect_sp, collect_alloc, last_ms, last_reason, sp_interval, alloc_thresh, if auto_sp {1} else {0}, gc_mode_s
+                );
+            } else if want_text {
+                eprintln!(
+                    "[GC] metrics: safepoints={} read_barriers={} write_barriers={} jit_handles={} allocs={} bytes={} collections={} (sp={} alloc={}) last_ms={} mode={}",
+                    sp, br, bw, handles, alloc_count, alloc_bytes, collect_total, collect_sp, collect_alloc, last_ms, gc_mode_s
+                );
+            }
+            // Threshold warning
+            if let Ok(s) = std::env::var("NYASH_GC_ALLOC_THRESHOLD") {
+                if let Ok(th) = s.parse::<u64>() {
+                    if alloc_bytes > th {
+                        eprintln!(
+                            "[GC][warn] allocation bytes {} exceeded threshold {}",
+                            alloc_bytes, th
+                        );
+                    }
+                }
+            }
+        }
+
+        // Leak diagnostics: report remaining JIT handles by type (Top-10)
+        if std::env::var("NYASH_GC_LEAK_DIAG").ok().as_deref() == Some("1") {
+            let tally = nyash_rust::jit::rt::handles::type_tally();
+            let total = tally.iter().map(|(_, n)| *n as u64).sum::<u64>();
+            if total > 0 {
+                eprintln!("[leak] Remaining handles by type (top 10):");
+                for (i, (ty, n)) in tally.into_iter().take(10).enumerate() {
+                    eprintln!("  {}. {} x{}", i + 1, ty, n);
+                }
+            }
+        }
         v as i32
     }
 }

crates/nyrt/src/plugin/console.rs

@@ -131,7 +131,7 @@ pub extern "C" fn nyash_console_readline_export() -> *mut i8 {
     // Use read_to_end if stdin is not a TTY? Simpler: read_line through BufRead
     // For simplicity, read from stdin into buffer until newline or EOF
     let mut buf = String::new();
-    let mut handle = io::stdin();
+    // Note: use std::io::stdin() directly without an unused handle binding
     // On failure or EOF, return empty string
     match io::stdin().read_line(&mut buf) {
         Ok(_n) => {

crates/nyrt/src/plugin/future.rs

@@ -114,7 +114,7 @@ pub extern "C" fn nyash_future_spawn_method_h(
     let handle =
         nyash_rust::jit::rt::handles::to_handle(fut_box.clone() as std::sync::Arc<dyn NyashBox>);
     // Copy data for async task
-    let mut cap: usize = 512;
+    let cap: usize = 512;
     let tlv = buf.clone();
     let inv = invoke.unwrap();
     nyash_rust::runtime::global_hooks::spawn_task(

crates/nyrt/src/plugin/invoke.rs

@@ -1,4 +1,5 @@
 use crate::encode::{nyrt_encode_arg_or_legacy, nyrt_encode_from_legacy_at};
+use crate::plugin::invoke_core;
 #[no_mangle]
 pub extern "C" fn nyash_plugin_invoke3_i64(
     type_id: i64,
@@ -8,39 +9,14 @@ pub extern "C" fn nyash_plugin_invoke3_i64(
     a1: i64,
     a2: i64,
 ) -> i64 {
-    use nyash_rust::runtime::plugin_loader_v2::PluginBoxV2;
-    // Resolve receiver instance from handle first; fallback to legacy VM args (param index)
-    let mut instance_id: u32 = 0;
-    let mut real_type_id: u32 = 0;
-    let mut invoke: Option<
-        unsafe extern "C" fn(u32, u32, u32, *const u8, usize, *mut u8, *mut usize) -> i32,
-    > = None;
-    if a0 > 0 {
-        if let Some(obj) = nyash_rust::jit::rt::handles::get(a0 as u64) {
-            if let Some(p) = obj.as_any().downcast_ref::<PluginBoxV2>() {
-                instance_id = p.instance_id();
-                real_type_id = p.inner.type_id;
-                invoke = Some(p.inner.invoke_fn);
-            }
-        }
-    }
-    if invoke.is_none()
-        && a0 >= 0
-        && std::env::var("NYASH_JIT_ARGS_HANDLE_ONLY").ok().as_deref() != Some("1")
-    {
-        nyash_rust::jit::rt::with_legacy_vm_args(|args| {
-            let idx = a0 as usize;
-            if let Some(nyash_rust::backend::vm::VMValue::BoxRef(b)) = args.get(idx) {
-                if let Some(p) = b.as_any().downcast_ref::<PluginBoxV2>() {
-                    instance_id = p.instance_id();
-                    invoke = Some(p.inner.invoke_fn);
-                }
-            }
-        });
-    }
-    if invoke.is_none() {
-        return 0;
-    }
+    // Resolve receiver via shared core helper
+    let recv = match invoke_core::resolve_receiver_for_a0(a0) {
+        Some(r) => r,
+        None => return 0,
+    };
+    let instance_id: u32 = recv.instance_id;
+    let _real_type_id: u32 = recv.real_type_id;
+    let invoke = recv.invoke;
     // Build TLV args from a1/a2 if present. Prefer handles/StringBox/IntegerBox via runtime host.
     use nyash_rust::{backend::vm::VMValue, jit::rt::handles};
     // argc from LLVM lowering is explicit arg count (excludes receiver)
@@ -48,164 +24,11 @@ pub extern "C" fn nyash_plugin_invoke3_i64(
     let mut buf = nyash_rust::runtime::plugin_ffi_common::encode_tlv_header(nargs as u16);
     // Encode legacy VM arg at position into provided buffer (avoid capturing &mut buf)
     let mut encode_from_legacy_into = |dst: &mut Vec<u8>, arg_pos: usize| {
-        nyash_rust::jit::rt::with_legacy_vm_args(|args| {
-            if let Some(v) = args.get(arg_pos) {
-                match v {
-                    VMValue::String(s) => {
-                        nyash_rust::runtime::plugin_ffi_common::encode::string(dst, s)
-                    }
-                    VMValue::Integer(i) => {
-                        nyash_rust::runtime::plugin_ffi_common::encode::i64(dst, *i)
-                    }
-                    VMValue::Float(f) => {
-                        nyash_rust::runtime::plugin_ffi_common::encode::f64(dst, *f)
-                    }
-                    VMValue::Bool(b) => {
-                        nyash_rust::runtime::plugin_ffi_common::encode::bool(dst, *b)
-                    }
-                    VMValue::BoxRef(b) => {
-                        // BufferBox → TLV bytes
-                        if let Some(bufbox) = b
-                            .as_any()
-                            .downcast_ref::<nyash_rust::boxes::buffer::BufferBox>()
-                        {
-                            nyash_rust::runtime::plugin_ffi_common::encode::bytes(
-                                dst,
-                                &bufbox.to_vec(),
-                            );
-                            return;
-                        }
-                        if let Some(p) = b.as_any().downcast_ref::<PluginBoxV2>() {
-                            // Prefer StringBox/IntegerBox primitives when possible
-                            let host = nyash_rust::runtime::get_global_plugin_host();
-                            if let Ok(hg) = host.read() {
-                                if p.box_type == "StringBox" {
-                                    if let Ok(Some(sb)) = hg.invoke_instance_method(
-                                        "StringBox",
-                                        "toUtf8",
-                                        p.instance_id(),
-                                        &[],
-                                    ) {
-                                        if let Some(s) = sb
-                                            .as_any()
-                                            .downcast_ref::<nyash_rust::box_trait::StringBox>()
-                                        {
-                                            nyash_rust::runtime::plugin_ffi_common::encode::string(
-                                                dst, &s.value,
-                                            );
-                                            return;
-                                        }
-                                    }
-                                } else if p.box_type == "IntegerBox" {
-                                    if let Ok(Some(ibx)) = hg.invoke_instance_method(
-                                        "IntegerBox",
-                                        "get",
-                                        p.instance_id(),
-                                        &[],
-                                    ) {
-                                        if let Some(i) =
-                                            ibx.as_any()
-                                                .downcast_ref::<nyash_rust::box_trait::IntegerBox>()
-                                        {
-                                            nyash_rust::runtime::plugin_ffi_common::encode::i64(
-                                                dst, i.value,
-                                            );
-                                            return;
-                                        }
-                                    }
-                                }
-                            }
-                            // Fallback: pass handle as plugin-handle TLV
-                            nyash_rust::runtime::plugin_ffi_common::encode::plugin_handle(
-                                dst,
-                                p.inner.type_id,
-                                p.instance_id(),
-                            );
-                        } else {
-                            // Stringify unknown boxes
-                            let s = b.to_string_box().value;
-                            nyash_rust::runtime::plugin_ffi_common::encode::string(dst, &s)
-                        }
-                    }
-                    _ => {}
-                }
-            }
-        });
+        nyrt_encode_from_legacy_at(dst, arg_pos)
     };
     // Encode argument value or fallback to legacy slot (avoid capturing &mut buf)
     let mut encode_arg_into = |dst: &mut Vec<u8>, val: i64, pos: usize| {
-        let mut appended = false;
-        // Try handle first
-        if val > 0 {
-            if let Some(obj) = handles::get(val as u64) {
-                // BufferBox handle → TLV bytes
-                if let Some(bufbox) = obj
-                    .as_any()
-                    .downcast_ref::<nyash_rust::boxes::buffer::BufferBox>()
-                {
-                    nyash_rust::runtime::plugin_ffi_common::encode::bytes(dst, &bufbox.to_vec());
-                    appended = true;
-                    return;
-                }
-                if let Some(p) = obj.as_any().downcast_ref::<PluginBoxV2>() {
-                    let host = nyash_rust::runtime::get_global_plugin_host();
-                    if let Ok(hg) = host.read() {
-                        if p.box_type == "StringBox" {
-                            if let Ok(Some(sb)) = hg.invoke_instance_method(
-                                "StringBox",
-                                "toUtf8",
-                                p.instance_id(),
-                                &[],
-                            ) {
-                                if let Some(s) = sb
-                                    .as_any()
-                                    .downcast_ref::<nyash_rust::box_trait::StringBox>()
-                                {
-                                    nyash_rust::runtime::plugin_ffi_common::encode::string(
-                                        dst, &s.value,
-                                    );
-                                    appended = true;
-                                    return;
-                                }
-                            }
-                        } else if p.box_type == "IntegerBox" {
-                            if let Ok(Some(ibx)) =
-                                hg.invoke_instance_method("IntegerBox", "get", p.instance_id(), &[])
-                            {
-                                if let Some(i) = ibx
-                                    .as_any()
-                                    .downcast_ref::<nyash_rust::box_trait::IntegerBox>()
-                                {
-                                    nyash_rust::runtime::plugin_ffi_common::encode::i64(
-                                        dst, i.value,
-                                    );
-                                    appended = true;
-                                    return;
-                                }
-                            }
-                        }
-                    }
-                    // Otherwise, pass as handle TLV
-                    nyash_rust::runtime::plugin_ffi_common::encode::plugin_handle(
-                        dst,
-                        p.inner.type_id,
-                        p.instance_id(),
-                    );
-                    appended = true;
-                    return;
-                }
-            }
-        }
-        // Legacy VM args by positional index (1-based for a1)
-        let before = dst.len();
-        encode_from_legacy_into(dst, pos);
-        if dst.len() != before {
-            appended = true;
-        }
-        // If still nothing appended (no-op), fallback to raw i64
-        if !appended {
-            nyash_rust::runtime::plugin_ffi_common::encode::i64(dst, val);
-        }
+        nyrt_encode_arg_or_legacy(dst, val, pos)
     };
     if nargs >= 1 {
         encode_arg_into(&mut buf, a1, 1);
@@ -219,123 +42,20 @@ pub extern "C" fn nyash_plugin_invoke3_i64(
             encode_from_legacy_into(&mut buf, pos);
         }
     }
-    // Prepare output buffer (dynamic growth on short buffer)
-    let mut cap: usize = 256;
-    let (mut tag_ret, mut sz_ret, mut payload_ret): (u8, usize, Vec<u8>) = (0, 0, Vec::new());
-    loop {
-        let mut out = vec![0u8; cap];
-        let mut out_len: usize = out.len();
-        let rc = unsafe {
-            invoke.unwrap()(
-                type_id as u32,
-                method_id as u32,
-                instance_id,
-                buf.as_ptr(),
-                buf.len(),
-                out.as_mut_ptr(),
-                &mut out_len,
-            )
-        };
-        if rc != 0 {
-            // Retry on short buffer hint (-1) or when plugin wrote beyond capacity (len > cap)
-            if rc == -1 || out_len > cap {
-                cap = cap.saturating_mul(2).max(out_len + 16);
-                if cap > 1 << 20 {
-                    break;
-                }
-                continue;
-            }
-            return 0;
-        }
-        let slice = &out[..out_len];
-        if let Some((t, s, p)) = nyash_rust::runtime::plugin_ffi_common::decode::tlv_first(slice) {
-            tag_ret = t;
-            sz_ret = s;
-            payload_ret = p.to_vec();
-        }
-        break;
-    }
-    if payload_ret.is_empty() {
-        return 0;
-    }
+    // Call invoke with dynamic buffer logic centralized
+    let (tag_ret, sz_ret, payload_ret): (u8, usize, Vec<u8>) = match invoke_core::plugin_invoke_call(
+        invoke,
+        type_id as u32,
+        method_id as u32,
+        instance_id,
+        &buf,
+    ) {
+        Some((t, s, p)) => (t, s, p),
+        None => return 0,
+    };
     if let Some((tag, sz, payload)) = Some((tag_ret, sz_ret, payload_ret.as_slice())) {
-        match tag {
-            2 => {
-                // I32
-                if let Some(v) = nyash_rust::runtime::plugin_ffi_common::decode::i32(payload) {
-                    return v as i64;
-                }
-            }
-            3 => {
-                // I64
-                if let Some(v) = nyash_rust::runtime::plugin_ffi_common::decode::i32(payload) {
-                    return v as i64;
-                }
-                if payload.len() == 8 {
-                    let mut b = [0u8; 8];
-                    b.copy_from_slice(payload);
-                    return i64::from_le_bytes(b);
-                }
-            }
-            6 | 7 => {
-                // String/Bytes -> register StringBox handle
-                use nyash_rust::box_trait::{NyashBox, StringBox};
-                let s = nyash_rust::runtime::plugin_ffi_common::decode::string(payload);
-                let arc: std::sync::Arc<dyn NyashBox> = std::sync::Arc::new(StringBox::new(s));
-                let h = nyash_rust::jit::rt::handles::to_handle(arc);
-                return h as i64;
-            }
-            8 => {
-                // Handle(tag=8) -> register and return handle id (i64)
-                if sz == 8 {
-                    let mut t = [0u8; 4];
-                    t.copy_from_slice(&payload[0..4]);
-                    let mut i = [0u8; 4];
-                    i.copy_from_slice(&payload[4..8]);
-                    let r_type = u32::from_le_bytes(t);
-                    let r_inst = u32::from_le_bytes(i);
-                    // Build PluginBoxV2 and register into handle-registry
-                    let meta_opt =
-                        nyash_rust::runtime::plugin_loader_v2::metadata_for_type_id(r_type);
-                    let (box_type_name, invoke_ptr) = if let Some(meta) = meta_opt {
-                        (meta.box_type.clone(), meta.invoke_fn)
-                    } else {
-                        ("PluginBox".to_string(), invoke.unwrap())
-                    };
-                    let pb = nyash_rust::runtime::plugin_loader_v2::make_plugin_box_v2(
-                        box_type_name.clone(),
-                        r_type,
-                        r_inst,
-                        invoke_ptr,
-                    );
-                    let arc: std::sync::Arc<dyn nyash_rust::box_trait::NyashBox> =
-                        std::sync::Arc::new(pb);
-                    let h = nyash_rust::jit::rt::handles::to_handle(arc);
-                    return h as i64;
-                }
-            }
-            1 => {
-                // Bool
-                return if nyash_rust::runtime::plugin_ffi_common::decode::bool(payload)
-                    .unwrap_or(false)
-                {
-                    1
-                } else {
-                    0
-                };
-            }
-            5 => {
-                // F64 → optional conversion to i64
-                if std::env::var("NYASH_JIT_NATIVE_F64").ok().as_deref() == Some("1") {
-                    if sz == 8 {
-                        let mut b = [0u8; 8];
-                        b.copy_from_slice(payload);
-                        let f = f64::from_le_bytes(b);
-                        return f as i64;
-                    }
-                }
-            }
-            _ => {}
+        if let Some(v) = invoke_core::decode_entry_to_i64(tag, sz, payload, invoke) {
+            return v;
         }
     }
     0
@@ -484,77 +204,7 @@ pub extern "C" fn nyash_plugin_invoke3_f64(
         });
     };
     let mut encode_arg = |val: i64, pos: usize| {
-        let mut appended = false;
-        if val > 0 {
-            if let Some(obj) = handles::get(val as u64) {
-                if let Some(bufbox) = obj
-                    .as_any()
-                    .downcast_ref::<nyash_rust::boxes::buffer::BufferBox>()
-                {
-                    nyash_rust::runtime::plugin_ffi_common::encode::bytes(
-                        &mut buf,
-                        &bufbox.to_vec(),
-                    );
-                    appended = true;
-                    return;
-                }
-                if let Some(p) = obj.as_any().downcast_ref::<PluginBoxV2>() {
-                    let host = nyash_rust::runtime::get_global_plugin_host();
-                    if let Ok(hg) = host.read() {
-                        if p.box_type == "StringBox" {
-                            if let Ok(Some(sb)) = hg.invoke_instance_method(
-                                "StringBox",
-                                "toUtf8",
-                                p.instance_id(),
-                                &[],
-                            ) {
-                                if let Some(s) = sb
-                                    .as_any()
-                                    .downcast_ref::<nyash_rust::box_trait::StringBox>()
-                                {
-                                    nyash_rust::runtime::plugin_ffi_common::encode::string(
-                                        &mut buf, &s.value,
-                                    );
-                                    appended = true;
-                                    return;
-                                }
-                            }
-                        } else if p.box_type == "IntegerBox" {
-                            if let Ok(Some(ibx)) =
-                                hg.invoke_instance_method("IntegerBox", "get", p.instance_id(), &[])
-                            {
-                                if let Some(i) = ibx
-                                    .as_any()
-                                    .downcast_ref::<nyash_rust::box_trait::IntegerBox>()
-                                {
-                                    nyash_rust::runtime::plugin_ffi_common::encode::i64(
-                                        &mut buf, i.value,
-                                    );
-                                    appended = true;
-                                    return;
-                                }
-                            }
-                        }
-                    }
-                    nyash_rust::runtime::plugin_ffi_common::encode::plugin_handle(
-                        &mut buf,
-                        p.inner.type_id,
-                        p.instance_id(),
-                    );
-                    appended = true;
-                    return;
-                }
-            }
-        }
-        let before = buf.len();
-        // Use global helper to avoid nested mutable borrows on buf
-        nyrt_encode_from_legacy_at(&mut buf, pos);
-        if buf.len() != before {
-            appended = true;
-        }
-        if !appended {
-            nyash_rust::runtime::plugin_ffi_common::encode::i64(&mut buf, val);
-        }
+        crate::encode::nyrt_encode_arg_or_legacy(&mut buf, val, pos)
     };
     if nargs >= 1 {
         encode_arg(a1, 1);
@@ -567,77 +217,20 @@ pub extern "C" fn nyash_plugin_invoke3_f64(
             nyrt_encode_from_legacy_at(&mut buf, pos);
         }
     }
-    // Prepare output buffer (dynamic growth on short buffer)
-    let mut cap: usize = 256;
-    let (mut tag_ret, mut sz_ret, mut payload_ret): (u8, usize, Vec<u8>) = (0, 0, Vec::new());
-    loop {
-        let mut out = vec![0u8; cap];
-        let mut out_len: usize = out.len();
-        let rc = unsafe {
-            invoke.unwrap()(
-                type_id as u32,
-                method_id as u32,
-                instance_id,
-                buf.as_ptr(),
-                buf.len(),
-                out.as_mut_ptr(),
-                &mut out_len,
-            )
-        };
-        if rc != 0 {
-            // Retry on short buffer (-1) or when plugin wrote beyond capacity
-            if rc == -1 || out_len > cap {
-                cap = cap.saturating_mul(2).max(out_len + 16);
-                if cap > 1 << 20 {
-                    break;
-                }
-                continue;
-            }
-            return 0.0;
-        }
-        let slice = &out[..out_len];
-        if let Some((t, s, p)) = nyash_rust::runtime::plugin_ffi_common::decode::tlv_first(slice) {
-            tag_ret = t;
-            sz_ret = s;
-            payload_ret = p.to_vec();
-        }
-        break;
-    }
-    if payload_ret.is_empty() {
-        return 0.0;
-    }
+    // Invoke via shared helper
+    let (mut tag_ret, mut sz_ret, mut payload_ret): (u8, usize, Vec<u8>) = match invoke_core::plugin_invoke_call(
+        invoke.unwrap(),
+        type_id as u32,
+        method_id as u32,
+        instance_id,
+        &buf,
+    ) {
+        Some((t, s, p)) => (t, s, p),
+        None => return 0.0,
+    };
     if let Some((tag, sz, payload)) = Some((tag_ret, sz_ret, payload_ret.as_slice())) {
-        match tag {
-            5 => {
-                // F64
-                if sz == 8 {
-                    let mut b = [0u8; 8];
-                    b.copy_from_slice(payload);
-                    return f64::from_le_bytes(b);
-                }
-            }
-            3 => {
-                // I64 -> f64
-                if let Some(v) = nyash_rust::runtime::plugin_ffi_common::decode::i32(payload) {
-                    return v as f64;
-                }
-                if payload.len() == 8 {
-                    let mut b = [0u8; 8];
-                    b.copy_from_slice(payload);
-                    return (i64::from_le_bytes(b)) as f64;
-                }
-            }
-            1 => {
-                // Bool -> f64
-                return if nyash_rust::runtime::plugin_ffi_common::decode::bool(payload)
-                    .unwrap_or(false)
-                {
-                    1.0
-                } else {
-                    0.0
-                };
-            }
-            _ => {}
+        if let Some(f) = invoke_core::decode_entry_to_f64(tag, sz, payload) {
+            return f;
         }
     }
     0.0
@@ -832,42 +425,10 @@ fn nyash_plugin_invoke_name_common_i64(method: &str, argc: i64, a0: i64, a1: i64
             &mut out_len,
         )
     };
-    if rc != 0 {
-        return 0;
-    }
+    if rc != 0 { return 0; }
     let out_slice = &out[..out_len];
-    if let Some((tag, _sz, payload)) =
-        nyash_rust::runtime::plugin_ffi_common::decode::tlv_first(out_slice)
-    {
-        match tag {
-            3 => {
-                if payload.len() == 8 {
-                    let mut b = [0u8; 8];
-                    b.copy_from_slice(payload);
-                    return i64::from_le_bytes(b);
-                }
-            }
-            1 => {
-                return if nyash_rust::runtime::plugin_ffi_common::decode::bool(payload)
-                    .unwrap_or(false)
-                {
-                    1
-                } else {
-                    0
-                };
-            }
-            5 => {
-                if std::env::var("NYASH_JIT_NATIVE_F64").ok().as_deref() == Some("1") {
-                    if payload.len() == 8 {
-                        let mut b = [0u8; 8];
-                        b.copy_from_slice(payload);
-                        let f = f64::from_le_bytes(b);
-                        return f as i64;
-                    }
-                }
-            }
-            _ => {}
-        }
+    if let Some((tag, sz, payload)) = nyash_rust::runtime::plugin_ffi_common::decode::tlv_first(out_slice) {
+        if let Some(v) = super::invoke_core::decode_entry_to_i64(tag, sz, payload, invoke.unwrap()) { return v; }
     }
     0
 }
@@ -1106,73 +667,8 @@ pub extern "C" fn nyash_plugin_invoke3_tagged_i64(
     if rc != 0 {
         return 0;
     }
-    if let Some((tag, _sz, payload)) =
-        nyash_rust::runtime::plugin_ffi_common::decode::tlv_first(&out[..out_len])
-    {
-        match tag {
-            2 => {
-                if let Some(v) = nyash_rust::runtime::plugin_ffi_common::decode::i32(payload) {
-                    return v as i64;
-                }
-            }
-            3 => {
-                if payload.len() == 8 {
-                    let mut b = [0u8; 8];
-                    b.copy_from_slice(payload);
-                    return i64::from_le_bytes(b);
-                }
-                if let Some(v) = nyash_rust::runtime::plugin_ffi_common::decode::i32(payload) {
-                    return v as i64;
-                }
-            }
-            6 | 7 => {
-                use nyash_rust::box_trait::{NyashBox, StringBox};
-                let s = nyash_rust::runtime::plugin_ffi_common::decode::string(payload);
-                let arc: std::sync::Arc<dyn NyashBox> = std::sync::Arc::new(StringBox::new(s));
-                let h = nyash_rust::jit::rt::handles::to_handle(arc);
-                return h as i64;
-            }
-            1 => {
-                return if nyash_rust::runtime::plugin_ffi_common::decode::bool(payload)
-                    .unwrap_or(false)
-                {
-                    1
-                } else {
-                    0
-                };
-            }
-            8 => {
-                if payload.len() == 8 {
-                    let mut t = [0u8; 4];
-                    t.copy_from_slice(&payload[0..4]);
-                    let mut i = [0u8; 4];
-                    i.copy_from_slice(&payload[4..8]);
-                    let r_type = u32::from_le_bytes(t);
-                    let r_inst = u32::from_le_bytes(i);
-                    let pb = nyash_rust::runtime::plugin_loader_v2::make_plugin_box_v2(
-                        "PluginBox".into(),
-                        r_type,
-                        r_inst,
-                        invoke.unwrap(),
-                    );
-                    let arc: std::sync::Arc<dyn nyash_rust::box_trait::NyashBox> =
-                        std::sync::Arc::new(pb);
-                    let h = nyash_rust::jit::rt::handles::to_handle(arc);
-                    return h as i64;
-                }
-            }
-            5 => {
-                if std::env::var("NYASH_JIT_NATIVE_F64").ok().as_deref() == Some("1") {
-                    if payload.len() == 8 {
-                        let mut b = [0u8; 8];
-                        b.copy_from_slice(payload);
-                        let f = f64::from_le_bytes(b);
-                        return f as i64;
-                    }
-                }
-            }
-            _ => {}
-        }
+    if let Some((tag, sz, payload)) = nyash_rust::runtime::plugin_ffi_common::decode::tlv_first(&out[..out_len]) {
+        if let Some(v) = invoke_core::decode_entry_to_i64(tag, sz, payload, invoke.unwrap()) { return v; }
     }
     0
 }
@@ -1263,73 +759,8 @@ pub extern "C" fn nyash_plugin_invoke_tagged_v_i64(
     if rc != 0 {
         return 0;
     }
-    if let Some((tag, _sz, payload)) =
-        nyash_rust::runtime::plugin_ffi_common::decode::tlv_first(&out[..out_len])
-    {
-        match tag {
-            2 => {
-                if let Some(v) = nyash_rust::runtime::plugin_ffi_common::decode::i32(payload) {
-                    return v as i64;
-                }
-            }
-            3 => {
-                if payload.len() == 8 {
-                    let mut b = [0u8; 8];
-                    b.copy_from_slice(payload);
-                    return i64::from_le_bytes(b);
-                }
-                if let Some(v) = nyash_rust::runtime::plugin_ffi_common::decode::i32(payload) {
-                    return v as i64;
-                }
-            }
-            6 | 7 => {
-                use nyash_rust::box_trait::{NyashBox, StringBox};
-                let s = nyash_rust::runtime::plugin_ffi_common::decode::string(payload);
-                let arc: std::sync::Arc<dyn NyashBox> = std::sync::Arc::new(StringBox::new(s));
-                let h = nyash_rust::jit::rt::handles::to_handle(arc);
-                return h as i64;
-            }
-            1 => {
-                return if nyash_rust::runtime::plugin_ffi_common::decode::bool(payload)
-                    .unwrap_or(false)
-                {
-                    1
-                } else {
-                    0
-                };
-            }
-            8 => {
-                if payload.len() == 8 {
-                    let mut t = [0u8; 4];
-                    t.copy_from_slice(&payload[0..4]);
-                    let mut i = [0u8; 4];
-                    i.copy_from_slice(&payload[4..8]);
-                    let r_type = u32::from_le_bytes(t);
-                    let r_inst = u32::from_le_bytes(i);
-                    let pb = nyash_rust::runtime::plugin_loader_v2::make_plugin_box_v2(
-                        "PluginBox".into(),
-                        r_type,
-                        r_inst,
-                        invoke.unwrap(),
-                    );
-                    let arc: std::sync::Arc<dyn nyash_rust::box_trait::NyashBox> =
-                        std::sync::Arc::new(pb);
-                    let h = nyash_rust::jit::rt::handles::to_handle(arc);
-                    return h as i64;
-                }
-            }
-            5 => {
-                if std::env::var("NYASH_JIT_NATIVE_F64").ok().as_deref() == Some("1") {
-                    if payload.len() == 8 {
-                        let mut b = [0u8; 8];
-                        b.copy_from_slice(payload);
-                        let f = f64::from_le_bytes(b);
-                        return f as i64;
-                    }
-                }
-            }
-            _ => {}
-        }
+    if let Some((tag, sz, payload)) = nyash_rust::runtime::plugin_ffi_common::decode::tlv_first(&out[..out_len]) {
+        if let Some(v) = invoke_core::decode_entry_to_i64(tag, sz, payload, invoke.unwrap()) { return v; }
     }
     0
 }

crates/nyrt/src/plugin/invoke_core.rs

@@ -0,0 +1,199 @@
+use nyash_rust::runtime::plugin_loader_v2::PluginBoxV2;
+
+/// Thin shared helpers for plugin invoke shims (i64/f64)
+///
+/// Goal: centralize receiver resolution and the dynamic buffer call loop,
+/// keeping extern functions in invoke.rs small and consistent.
+
+pub struct Receiver {
+    pub instance_id: u32,
+    pub real_type_id: u32,
+    pub invoke:
+        unsafe extern "C" fn(u32, u32, u32, *const u8, usize, *mut u8, *mut usize) -> i32,
+}
+
+/// Resolve receiver from a0: prefer handle registry; fallback to legacy VM args when allowed.
+pub fn resolve_receiver_for_a0(a0: i64) -> Option<Receiver> {
+    // 1) Handle registry (preferred)
+    if a0 > 0 {
+        if let Some(obj) = nyash_rust::jit::rt::handles::get(a0 as u64) {
+            if let Some(p) = obj.as_any().downcast_ref::<PluginBoxV2>() {
+                return Some(Receiver {
+                    instance_id: p.instance_id(),
+                    real_type_id: p.inner.type_id,
+                    invoke: p.inner.invoke_fn,
+                });
+            }
+        }
+    }
+    // 2) Legacy VM args (index by a0) unless handle-only is enforced
+    if a0 >= 0
+        && std::env::var("NYASH_JIT_ARGS_HANDLE_ONLY").ok().as_deref() != Some("1")
+    {
+        nyash_rust::jit::rt::with_legacy_vm_args(|args| {
+            let idx = a0 as usize;
+            if let Some(nyash_rust::backend::vm::VMValue::BoxRef(b)) = args.get(idx) {
+                if let Some(p) = b.as_any().downcast_ref::<PluginBoxV2>() {
+                    return Some(Receiver {
+                        instance_id: p.instance_id(),
+                        real_type_id: p.inner.type_id,
+                        invoke: p.inner.invoke_fn,
+                    });
+                }
+            }
+            None
+        })
+    } else {
+        None
+    }
+}
+
+/// Call plugin invoke with dynamic buffer growth, returning first TLV entry on success.
+pub fn plugin_invoke_call(
+    invoke: unsafe extern "C" fn(u32, u32, u32, *const u8, usize, *mut u8, *mut usize) -> i32,
+    type_id: u32,
+    method_id: u32,
+    instance_id: u32,
+    tlv_args: &[u8],
+) -> Option<(u8, usize, Vec<u8>)> {
+    let mut cap: usize = 256;
+    let mut tag_ret: u8 = 0;
+    let mut sz_ret: usize = 0;
+    let mut payload_ret: Vec<u8> = Vec::new();
+    loop {
+        let mut out = vec![0u8; cap];
+        let mut out_len: usize = out.len();
+        let rc = unsafe {
+            invoke(
+                type_id,
+                method_id,
+                instance_id,
+                tlv_args.as_ptr(),
+                tlv_args.len(),
+                out.as_mut_ptr(),
+                &mut out_len,
+            )
+        };
+        if rc != 0 {
+            // Retry on short buffer hint (-1) or when plugin wrote beyond capacity (len > cap)
+            if rc == -1 || out_len > cap {
+                cap = cap.saturating_mul(2).max(out_len + 16);
+                if cap > 1 << 20 {
+                    break;
+                }
+                continue;
+            }
+            return None;
+        }
+        let slice = &out[..out_len];
+        if let Some((t, s, p)) = nyash_rust::runtime::plugin_ffi_common::decode::tlv_first(slice) {
+            tag_ret = t;
+            sz_ret = s;
+            payload_ret = p.to_vec();
+        }
+        break;
+    }
+    if payload_ret.is_empty() {
+        return None;
+    }
+    Some((tag_ret, sz_ret, payload_ret))
+}
+
+/// Decode a single TLV entry to i64 with side-effects (handle registration) when applicable.
+pub fn decode_entry_to_i64(
+    tag: u8,
+    sz: usize,
+    payload: &[u8],
+    fallback_invoke: unsafe extern "C" fn(u32, u32, u32, *const u8, usize, *mut u8, *mut usize) -> i32,
+) -> Option<i64> {
+    match tag {
+        2 => nyash_rust::runtime::plugin_ffi_common::decode::i32(payload).map(|v| v as i64),
+        3 => {
+            if let Some(v) = nyash_rust::runtime::plugin_ffi_common::decode::i32(payload) {
+                return Some(v as i64);
+            }
+            if payload.len() == 8 {
+                let mut b = [0u8; 8];
+                b.copy_from_slice(payload);
+                return Some(i64::from_le_bytes(b));
+            }
+            None
+        }
+        6 | 7 => {
+            use nyash_rust::box_trait::{NyashBox, StringBox};
+            let s = nyash_rust::runtime::plugin_ffi_common::decode::string(payload);
+            let arc: std::sync::Arc<dyn NyashBox> = std::sync::Arc::new(StringBox::new(s));
+            let h = nyash_rust::jit::rt::handles::to_handle(arc);
+            Some(h as i64)
+        }
+        8 => {
+            if sz == 8 {
+                let mut t = [0u8; 4];
+                t.copy_from_slice(&payload[0..4]);
+                let mut i = [0u8; 4];
+                i.copy_from_slice(&payload[4..8]);
+                let r_type = u32::from_le_bytes(t);
+                let r_inst = u32::from_le_bytes(i);
+                // Use metadata if available to set box_type/invoke_fn
+                let meta_opt = nyash_rust::runtime::plugin_loader_v2::metadata_for_type_id(r_type);
+                let (box_type_name, invoke_ptr) = if let Some(meta) = meta_opt {
+                    (meta.box_type.clone(), meta.invoke_fn)
+                } else {
+                    ("PluginBox".to_string(), fallback_invoke)
+                };
+                let pb = nyash_rust::runtime::plugin_loader_v2::make_plugin_box_v2(
+                    box_type_name,
+                    r_type,
+                    r_inst,
+                    invoke_ptr,
+                );
+                let arc: std::sync::Arc<dyn nyash_rust::box_trait::NyashBox> =
+                    std::sync::Arc::new(pb);
+                let h = nyash_rust::jit::rt::handles::to_handle(arc);
+                return Some(h as i64);
+            }
+            None
+        }
+        1 => nyash_rust::runtime::plugin_ffi_common::decode::bool(payload)
+            .map(|b| if b { 1 } else { 0 }),
+        5 => {
+            if std::env::var("NYASH_JIT_NATIVE_F64").ok().as_deref() == Some("1") && sz == 8 {
+                let mut b = [0u8; 8];
+                b.copy_from_slice(payload);
+                let f = f64::from_le_bytes(b);
+                return Some(f as i64);
+            }
+            None
+        }
+        _ => None,
+    }
+}
+
+/// Decode a single TLV entry to f64 when possible.
+pub fn decode_entry_to_f64(tag: u8, sz: usize, payload: &[u8]) -> Option<f64> {
+    match tag {
+        5 => {
+            if sz == 8 {
+                let mut b = [0u8; 8];
+                b.copy_from_slice(payload);
+                Some(f64::from_le_bytes(b))
+            } else {
+                None
+            }
+        }
+        3 => {
+            if let Some(v) = nyash_rust::runtime::plugin_ffi_common::decode::i32(payload) {
+                return Some(v as f64);
+            }
+            if payload.len() == 8 {
+                let mut b = [0u8; 8];
+                b.copy_from_slice(payload);
+                return Some((i64::from_le_bytes(b)) as f64);
+            }
+            None
+        }
+        1 => nyash_rust::runtime::plugin_ffi_common::decode::bool(payload)
+            .map(|b| if b { 1.0 } else { 0.0 }),
+        _ => None,
+    }
+}

crates/nyrt/src/plugin/mod.rs

@@ -4,6 +4,7 @@ pub mod console;
 pub mod future;
 pub mod instance;
 pub mod invoke;
+pub mod invoke_core;
 pub mod map;
 pub mod semantics;
 pub mod string;
@@ -14,6 +15,7 @@ pub use console::*;
 pub use future::*;
 pub use instance::*;
 pub use invoke::*;
+pub use invoke_core::*;
 pub use map::*;
 pub use semantics::*;
 pub use string::*;

docs/LLVM_HARNESS.md

@@ -16,6 +16,12 @@ Protocol
 - Output: `.o` オブジェクト（既定: `NYASH_AOT_OBJECT_OUT` または `NYASH_LLVM_OBJ_OUT`）。
 - 入口: `ny_main() -> i64`（戻り値は exit code 相当。必要時 handle 正規化を行う）。
 
+CLI（crate）
+- `crates/nyash-llvm-compiler` 提供の `ny-llvmc` は llvmlite ハーネスの薄ラッパーだよ。
+  - ダミー: `./target/release/ny-llvmc --dummy --out /tmp/dummy.o`
+  - JSON から: `./target/release/ny-llvmc --in mir.json --out out.o`
+  - 既定のハーネスパスは `tools/llvmlite_harness.py`。変更は `--harness <path>` で上書き可。
+
 Quick Start
 - 依存: `python3 -m pip install llvmlite`
 - ダミー生成（配線検証）:
@@ -41,5 +47,9 @@ Notes
 - 初版は固定 `ny_main` から開始してもよい（配線確認）。以降、MIR 命令を順次対応。
 - ハーネスは自律（外部状態に依存しない）。エラーは即 stderr に詳細を出す。
 
+Schema Validation（任意）
+- JSON v0 のスキーマは `docs/reference/mir/json_v0.schema.json` にあるよ。
+- 検証: `python3 tools/validate_mir_json.py <mir.json>`（要: `python3 -m pip install jsonschema`）。
+
 Appendix: 静的リンクについて
 - 生成 EXE は NyRT（libnyrt.a）を静的リンク。完全静的（-static）は musl 推奨（dlopen 不可になるため動的プラグインは使用不可）。

docs/README.md

@@ -55,6 +55,7 @@
 - [言語リファレンス](reference/language/LANGUAGE_REFERENCE_2025.md)
 - [アーキテクチャ概要](reference/architecture/TECHNICAL_ARCHITECTURE_2025.md)
 - [実行バックエンド](reference/architecture/execution-backends.md)
+- [GC モードと運用](reference/runtime/gc.md)
 - [プラグインシステム](reference/plugin-system/)
  - [CLIオプション早見表](tools/cli-options.md)
  

docs/guides/selfhost-pilot.md

@@ -0,0 +1,36 @@
+Self‑Hosting Pilot — Quick Guide (Phase‑15)
+
+Overview
+- Goal: Run Ny→JSON v0 via the selfhost compiler path and execute with PyVM/LLVM.
+- Default remains env‑gated for safety; CI runs smokes to build confidence.
+
+Recommended Flows
+- Runner (pilot): `NYASH_USE_NY_COMPILER=1 ./target/release/nyash --backend vm apps/examples/string_p0.nyash`
+- Emit‑only: `NYASH_USE_NY_COMPILER=1 NYASH_NY_COMPILER_EMIT_ONLY=1 ...`
+- EXE‑first (parser EXE): `tools/build_compiler_exe.sh && NYASH_USE_NY_COMPILER=1 NYASH_USE_NY_COMPILER_EXE=1 ./target/release/nyash --backend vm apps/examples/string_p0.nyash`
+- LLVM AOT: `NYASH_LLVM_USE_HARNESS=1 tools/build_llvm.sh apps/... -o app && ./app`
+
+CI Workflows
+- Selfhost Bootstrap (always): `.github/workflows/selfhost-bootstrap.yml`
+  - Builds nyash (`cranelift-jit`) and runs `tools/bootstrap_selfhost_smoke.sh`.
+- Selfhost EXE‑first (optional): `.github/workflows/selfhost-exe-first.yml`
+  - Installs LLVM 18 + llvmlite, then runs `tools/exe_first_smoke.sh`.
+
+Useful Env Flags
+- `NYASH_USE_NY_COMPILER=1`: Enable selfhost compiler pipeline.
+- `NYASH_NY_COMPILER_EMIT_ONLY=1`: Print JSON v0 only (no execution).
+- `NYASH_NY_COMPILER_TIMEOUT_MS=4000`: Child timeout (ms). Default 2000.
+- `NYASH_USE_NY_COMPILER_EXE=1`: Prefer external parser EXE.
+- `NYASH_NY_COMPILER_EXE_PATH=<path>`: Override EXE path.
+- `NYASH_SELFHOST_READ_TMP=1`: Child reads `tmp/ny_parser_input.ny` when supported.
+
+Troubleshooting (short)
+- No Python found: install `python3` (PyVM / harness).
+- No `llvm-config-18`: install LLVM 18 dev (see EXE‑first workflow).
+- llvmlite import error: `python3 -m pip install llvmlite`.
+- Parser child timeout: raise `NYASH_NY_COMPILER_TIMEOUT_MS`.
+- EXE‑first bridge mismatch: re‑run with `NYASH_CLI_VERBOSE=1` and keep `dist/nyash_compiler/sample.json` for inspection.
+
+Notes
+- JSON v0 schema is stable but not yet versioned; validation is planned.
+- Default backend `vm` maps to PyVM unless legacy VM features are enabled.

docs/reference/mir/json_v0.schema.json

@@ -0,0 +1,96 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://nyash.dev/schema/mir/json_v0.schema.json",
+  "title": "Nyash MIR JSON v0",
+  "type": "object",
+  "additionalProperties": true,
+  "properties": {
+    "schema_version": { "type": ["integer", "string" ] },
+    "functions": {
+      "oneOf": [
+        { "$ref": "#/definitions/functionList" },
+        { "$ref": "#/definitions/functionMap" }
+      ]
+    }
+  },
+  "required": ["functions"],
+  "definitions": {
+    "functionList": {
+      "type": "array",
+      "items": { "$ref": "#/definitions/function" }
+    },
+    "functionMap": {
+      "type": "object",
+      "additionalProperties": { "$ref": "#/definitions/functionBody" }
+    },
+    "function": {
+      "type": "object",
+      "additionalProperties": true,
+      "properties": {
+        "name": { "type": "string" },
+        "params": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "additionalProperties": true,
+            "properties": {
+              "name": { "type": "string" },
+              "type": { "type": "string" }
+            },
+            "required": ["name", "type"]
+          }
+        },
+        "return_type": { "type": "string" },
+        "entry_block": { "type": ["integer", "string"] },
+        "blocks": { "$ref": "#/definitions/blocks" }
+      },
+      "required": ["name", "blocks"]
+    },
+    "functionBody": {
+      "type": "object",
+      "additionalProperties": true,
+      "properties": {
+        "params": { "$ref": "#/definitions/function/properties/params" },
+        "return_type": { "type": "string" },
+        "entry_block": { "type": ["integer", "string"] },
+        "blocks": { "$ref": "#/definitions/blocks" }
+      },
+      "required": ["blocks"]
+    },
+    "blocks": {
+      "oneOf": [
+        {
+          "type": "array",
+          "items": { "$ref": "#/definitions/block" }
+        },
+        {
+          "type": "object",
+          "additionalProperties": { "$ref": "#/definitions/block" }
+        }
+      ]
+    },
+    "block": {
+      "type": "object",
+      "additionalProperties": true,
+      "properties": {
+        "id": { "type": ["integer", "string"] },
+        "instructions": { "$ref": "#/definitions/instructions" },
+        "terminator": { "$ref": "#/definitions/instruction" }
+      },
+      "required": ["id", "instructions"]
+    },
+    "instructions": {
+      "type": "array",
+      "items": { "$ref": "#/definitions/instruction" }
+    },
+    "instruction": {
+      "type": "object",
+      "additionalProperties": true,
+      "properties": {
+        "kind": { "type": "string" }
+      },
+      "required": ["kind"]
+    }
+  }
+}
+

docs/reference/runtime/gc.md

@@ -0,0 +1,62 @@
+Nyash GC Modes — Design and Usage
+
+Overview
+- Nyash adopts a pragmatic GC strategy that balances safety, performance, and simplicity.
+- Default is reference counting with a periodic cycle collector; advanced modes exist for tuning and debugging.
+
+User‑Facing Modes (recommended)
+- rc+cycle (default, safe)
+  - Reference counting with periodic cycle detection/collection.
+  - Recommended for most applications; memory leaks from cycles are handled.
+- minorgen (high‑performance)
+  - Lightweight generational GC: moving nursery (Gen‑0), non‑moving upper generations.
+  - Write barrier (old→new) is minimal; plugin/FFI objects remain non‑moving via handle indirection.
+
+Advanced Modes (for language dev/debug)
+- stw (debug/verification)
+  - Non‑moving stop‑the‑world mark‑and‑sweep. Useful for strict correctness checks and leak cause isolation.
+- rc (baseline for comparisons)
+  - rc+cycle with cycle detection disabled. For performance comparisons or targeted debugging.
+- off (expert, self‑responsibility)
+  - Cycle detection and tracing off. Use only when cycles are guaranteed not to occur. Not recommended for long‑running services.
+
+Selection & Precedence
+- CLI: `--gc {auto,rc+cycle,minorgen,stw,rc,off}` (auto = rc+cycle)
+- ENV: `NYASH_GC_MODE` (overridden by CLI)
+- nyash.toml [env] applies last
+
+Instrumentation & Diagnostics
+- `NYASH_GC_METRICS=1`: print brief metrics (allocs/bytes/cycles/pauses)
+- `NYASH_GC_METRICS_JSON=1`: emit JSON metrics for CI/aggregation
+- `NYASH_GC_LEAK_DIAG=1`: on exit, dump suspected unreleased objects (Top‑K by type/site)
+- `NYASH_GC_ALLOC_THRESHOLD=<N>`: warn or fail when allocations/bytes exceed threshold
+
+Operational Guidance
+- Default: rc+cycle for stable operations.
+- Try minorgen when throughput/latency matter; it will fall back to rc+cycle on unsupported platforms or when plugin objects are declared non‑moving.
+- off/rc are for special cases only; prefer enabling leak diagnostics when using them in development.
+
+Implementation Roadmap (Step‑wise)
+1) Wiring & Observability
+   - Introduce `GcMode`, `GcController`, unify roots (handles, globals, frames) and safepoints.
+   - Add `LeakRegistry` (allocation ledger) and exit‑time dump.
+   - Ship rc+cycle (trial deletion) behind the controller (dev default can be rc+cycle).
+2) minorgen (nursery)
+   - Moving Gen‑0 with simple promotion; upper generations non‑moving mark‑sweep.
+   - Minimal write barrier (old→new card marking). Plugin/FFI remain non‑moving.
+3) stw (dev verify)
+   - Non‑moving STW mark‑and‑sweep for correctness checks.
+
+Notes
+- Safepoint and barrier MIR ops already exist and are reused as GC coordination hooks.
+- Handle indirection keeps future moving GCs compatible with plugin/FFI boundaries.
+
+LLVM Safepoints
+- Automatic safepoint insertion can be toggled for the LLVM harness/backend:
+  - NYASH_LLVM_AUTO_SAFEPOINT=1 enables insertion (default 1)
+  - Injection points: loop headers, function calls, externcalls, and selected boxcalls.
+  - Safepoints call ny_check_safepoint/ny_safepoint in NyRT, which forwards to runtime hooks (GC.safepoint + scheduler poll).
+
+Controller & Metrics
+- The unified GcController implements GcHooks and aggregates metrics (safepoints/read/write/alloc).
+- CountingGc is a thin wrapper around GcController for compatibility.

docs/tools/cli-options.md

@@ -16,6 +16,19 @@
 - `--vm-stats`: VM命令統計を有効化（`NYASH_VM_STATS=1`）
 - `--vm-stats-json`: VM統計をJSONで出力（`NYASH_VM_STATS_JSON=1`）
 
+## GC
+- `--gc {auto|rc+cycle|minorgen|stw|rc|off}`: GCモード（既定: `auto` → rc+cycle）
+  - `rc+cycle`: 参照カウント + 循環回収（推奨・安定）
+  - `minorgen`: 高速向けの軽量世代別（Gen‑0移動、上位非移動）
+  - `stw`: 検証用の非移動Mark‑Sweep（開発者向け）
+  - `rc`: 循環回収なしのRC（比較用）
+  - `off`: 自己責任モード（循環はリーク）
+- 関連ENV
+  - `NYASH_GC_MODE`（CLIが優先）
+  - `NYASH_GC_METRICS` / `NYASH_GC_METRICS_JSON`
+  - `NYASH_GC_LEAK_DIAG` / `NYASH_GC_ALLOC_THRESHOLD`
+  - 詳細: `docs/reference/runtime/gc.md`
+
 ## WASM/AOT
 - `--compile-wasm`: WATを出力
 - `--compile-native` / `--aot`: AOT実行ファイル出力（要wasm-backend）

src/cli.rs

@@ -58,6 +58,8 @@ pub struct CliConfig {
     // Phase-15: JSON IR v0 bridge
     pub ny_parser_pipe: bool,
     pub json_file: Option<String>,
+    // GC mode (dev; forwarded to env as NYASH_GC_MODE)
+    pub gc_mode: Option<String>,
     // Build system (MVP)
     pub build_path: Option<String>,
     pub build_app: Option<String>,
@@ -105,6 +107,12 @@ impl CliConfig {
                     .value_name("FILE")
                     .index(1)
             )
+            .arg(
+                Arg::new("gc")
+                    .long("gc")
+                    .value_name("{auto,rc+cycle,minorgen,stw,rc,off}")
+                    .help("Select GC mode (default: rc+cycle)")
+            )
             .arg(
                 Arg::new("parser")
                     .long("parser")
@@ -456,6 +464,7 @@ impl CliConfig {
             cli_verbose: matches.get_flag("verbose"),
             run_task: matches.get_one::<String>("run-task").cloned(),
             load_ny_plugins: matches.get_flag("load-ny-plugins"),
+            gc_mode: matches.get_one::<String>("gc").cloned(),
             parser_ny: matches
                 .get_one::<String>("parser")
                 .map(|s| s == "ny")
@@ -516,6 +525,7 @@ impl Default for CliConfig {
             cli_verbose: false,
             run_task: None,
             load_ny_plugins: false,
+            gc_mode: None,
             parser_ny: false,
             ny_parser_pipe: false,
             json_file: None,

src/config/env.rs

@@ -211,6 +211,41 @@ pub fn gc_trace_level() -> u8 {
     }
 }
 
+// ---- GC mode and instrumentation ----
+/// Return current GC mode string (auto default = "rc+cycle").
+/// Allowed: "auto", "rc+cycle", "minorgen", "stw", "rc", "off"
+pub fn gc_mode() -> String {
+    match std::env::var("NYASH_GC_MODE").ok() {
+        Some(m) if !m.trim().is_empty() => m,
+        _ => "rc+cycle".to_string(),
+    }
+}
+/// Brief metrics emission (text)
+pub fn gc_metrics() -> bool {
+    std::env::var("NYASH_GC_METRICS").ok().as_deref() == Some("1")
+}
+/// JSON metrics emission (single line)
+pub fn gc_metrics_json() -> bool {
+    std::env::var("NYASH_GC_METRICS_JSON").ok().as_deref() == Some("1")
+}
+/// Leak diagnostics on exit
+pub fn gc_leak_diag() -> bool {
+    std::env::var("NYASH_GC_LEAK_DIAG").ok().as_deref() == Some("1")
+}
+/// Optional allocation threshold; if Some(n) and exceeded, print warning
+pub fn gc_alloc_threshold() -> Option<u64> {
+    std::env::var("NYASH_GC_ALLOC_THRESHOLD").ok()?.parse().ok()
+}
+
+/// Run a collection every N safepoints (if Some)
+pub fn gc_collect_sp_interval() -> Option<u64> {
+    std::env::var("NYASH_GC_COLLECT_SP").ok()?.parse().ok()
+}
+/// Run a collection when allocated bytes since last >= N (if Some)
+pub fn gc_collect_alloc_bytes() -> Option<u64> {
+    std::env::var("NYASH_GC_COLLECT_ALLOC").ok()?.parse().ok()
+}
+
 // ---- Rewriter flags (optimizer transforms)
 pub fn rewrite_debug() -> bool {
     std::env::var("NYASH_REWRITE_DEBUG").ok().as_deref() == Some("1")

src/jit/rt.rs

@@ -162,6 +162,28 @@ pub mod handles {
     pub fn len() -> usize {
         REG.with(|cell| cell.borrow().map.len())
     }
+    /// Tally handles by NyashBox type name (best-effort)
+    pub fn type_tally() -> Vec<(String, usize)> {
+        use std::collections::HashMap;
+        REG.with(|cell| {
+            let reg = cell.borrow();
+            let mut map: HashMap<String, usize> = HashMap::new();
+            for (_h, obj) in reg.map.iter() {
+                let tn = obj.type_name().to_string();
+                *map.entry(tn).or_insert(0) += 1;
+            }
+            let mut v: Vec<(String, usize)> = map.into_iter().collect();
+            v.sort_by(|a, b| b.1.cmp(&a.1).then_with(|| a.0.cmp(&b.0)));
+            v
+        })
+    }
+    /// Snapshot current handle objects (Arc clones)
+    pub fn snapshot_arcs() -> Vec<Arc<dyn crate::box_trait::NyashBox>> {
+        REG.with(|cell| {
+            let reg = cell.borrow();
+            reg.map.values().cloned().collect()
+        })
+    }
 
     // Scope management: track and clear handles created within a JIT call
     pub fn begin_scope() {

src/llvm_py/instructions/barrier.py

@@ -51,7 +51,8 @@ def lower_atomic_op(
     resolver=None,
     preds=None,
     block_end_values=None,
-    bb_map=None
+    bb_map=None,
+    ctx=None,
 ) -> None:
     """
     Lower atomic operations
@@ -66,7 +67,12 @@ def lower_atomic_op(
         ordering: Memory ordering
     """
     # Get pointer
-    if resolver is not None and preds is not None and block_end_values is not None and bb_map is not None:
+    if ctx is not None:
+        try:
+            ptr = ctx.resolver.resolve_ptr(ptr_vid, builder.block, ctx.preds, ctx.block_end_values, ctx.vmap)
+        except Exception:
+            ptr = vmap.get(ptr_vid)
+    elif resolver is not None and preds is not None and block_end_values is not None and bb_map is not None:
         ptr = resolver.resolve_ptr(ptr_vid, builder.block, preds, block_end_values, vmap)
     else:
         ptr = vmap.get(ptr_vid)
@@ -85,7 +91,12 @@ def lower_atomic_op(
     elif op == "store":
         # Atomic store
         if val_vid is not None:
-            if resolver is not None and preds is not None and block_end_values is not None and bb_map is not None:
+            if ctx is not None:
+                try:
+                    val = ctx.resolver.resolve_i64(val_vid, builder.block, ctx.preds, ctx.block_end_values, ctx.vmap, ctx.bb_map)
+                except Exception:
+                    val = vmap.get(val_vid, ir.Constant(ir.IntType(64), 0))
+            elif resolver is not None and preds is not None and block_end_values is not None and bb_map is not None:
                 val = resolver.resolve_i64(val_vid, builder.block, preds, block_end_values, vmap, bb_map)
             else:
                 val = vmap.get(val_vid, ir.Constant(ir.IntType(64), 0))
@@ -94,7 +105,12 @@ def lower_atomic_op(
     elif op == "add":
         # Atomic add (fetch_add)
         if val_vid is not None:
-            if resolver is not None and preds is not None and block_end_values is not None and bb_map is not None:
+            if ctx is not None:
+                try:
+                    val = ctx.resolver.resolve_i64(val_vid, builder.block, ctx.preds, ctx.block_end_values, ctx.vmap, ctx.bb_map)
+                except Exception:
+                    val = ir.Constant(ir.IntType(64), 1)
+            elif resolver is not None and preds is not None and block_end_values is not None and bb_map is not None:
                 val = resolver.resolve_i64(val_vid, builder.block, preds, block_end_values, vmap, bb_map)
             else:
                 val = ir.Constant(ir.IntType(64), 1)

src/llvm_py/instructions/boxcall.py

@@ -5,6 +5,7 @@ Core of Nyash's "Everything is Box" philosophy
 
 import llvmlite.ir as ir
 from typing import Dict, List, Optional, Any
+from instructions.safepoint import insert_automatic_safepoint
 
 def _declare(module: ir.Module, name: str, ret, args):
     for f in module.functions:
@@ -68,6 +69,13 @@ def lower_boxcall(
     i64 = ir.IntType(64)
     i8 = ir.IntType(8)
     i8p = i8.as_pointer()
+    # Insert a safepoint around potential heavy boxcall sites (pre-call)
+    try:
+        import os
+        if os.environ.get('NYASH_LLVM_AUTO_SAFEPOINT', '1') == '1':
+            insert_automatic_safepoint(builder, module, "boxcall")
+    except Exception:
+        pass
 
     # Short-hands with ctx (backward-compatible fallback)
     r = resolver

src/llvm_py/instructions/call.py

@@ -6,6 +6,7 @@ Handles regular function calls (not BoxCall or ExternCall)
 import llvmlite.ir as ir
 from typing import Dict, List, Optional, Any
 from trace import debug as trace_debug
+from instructions.safepoint import insert_automatic_safepoint
 
 def lower_call(
     builder: ir.IRBuilder,
@@ -45,6 +46,13 @@ def lower_call(
                 bb_map = ctx.bb_map
         except Exception:
             pass
+    # Insert an automatic safepoint after the function call
+    try:
+        import os
+        if os.environ.get('NYASH_LLVM_AUTO_SAFEPOINT', '1') == '1':
+            insert_automatic_safepoint(builder, module, "function_call")
+    except Exception:
+        pass
     # Short-hands with ctx (backward-compatible fallback)
     r = resolver
     p = preds

src/llvm_py/instructions/controlflow/while_.py

@@ -4,6 +4,7 @@ Lowering helpers for while-control flow (regular structured)
 
 from typing import List, Dict, Any
 import llvmlite.ir as ir
+from instructions.safepoint import insert_automatic_safepoint
 
 def lower_while_regular(
     builder: ir.IRBuilder,
@@ -57,6 +58,13 @@ def lower_while_regular(
     else:
         cond_val = ir.Constant(i1, 0)
 
+    # Insert a safepoint at loop header to allow cooperative GC
+    try:
+        import os
+        if os.environ.get('NYASH_LLVM_AUTO_SAFEPOINT', '1') == '1':
+            insert_automatic_safepoint(cbuild, builder.block.parent.module, "loop_header")
+    except Exception:
+        pass
     cbuild.cbranch(cond_val, body_bb, exit_bb)
 
     # Body block
@@ -77,4 +85,3 @@ def lower_while_regular(
 
     # Continue at exit
     builder.position_at_end(exit_bb)
-

src/llvm_py/instructions/externcall.py

@@ -5,6 +5,7 @@ Minimal mapping for NyRT-exported symbols (console/log family等)
 
 import llvmlite.ir as ir
 from typing import Dict, List, Optional, Any
+from instructions.safepoint import insert_automatic_safepoint
 
 def lower_externcall(
     builder: ir.IRBuilder,
@@ -197,3 +198,10 @@ def lower_externcall(
             vmap[dst_vid] = ir.Constant(i64, 0)
         else:
             vmap[dst_vid] = result
+    # Insert an automatic safepoint after externcall
+    try:
+        import os
+        if os.environ.get('NYASH_LLVM_AUTO_SAFEPOINT', '1') == '1':
+            insert_automatic_safepoint(builder, module, "extern_call")
+    except Exception:
+        pass

src/llvm_py/instructions/loopform.py

@@ -7,6 +7,7 @@ import os
 import llvmlite.ir as ir
 from dataclasses import dataclass
 from typing import Dict, Tuple, List, Optional, Any
+from instructions.safepoint import insert_automatic_safepoint
 
 @dataclass
 class LoopFormContext:
@@ -53,7 +54,8 @@ def lower_while_loopform(
     bb_map: Dict[int, ir.Block],
     resolver=None,
     preds=None,
-    block_end_values=None
+    block_end_values=None,
+    ctx=None,
 ) -> bool:
     """
     Lower a while loop using LoopForm structure
@@ -72,9 +74,22 @@ def lower_while_loopform(
     builder.position_at_end(lf.preheader)
     builder.branch(lf.header)
     
-    # Header: Evaluate condition
+    # Header: Evaluate condition (insert a safepoint at loop header)
     builder.position_at_end(lf.header)
-    if resolver is not None and preds is not None and block_end_values is not None:
+    try:
+        import os
+        if os.environ.get('NYASH_LLVM_AUTO_SAFEPOINT', '1') == '1':
+            insert_automatic_safepoint(builder, func.module, "loop_header")
+    except Exception:
+        pass
+    if ctx is not None:
+        try:
+            cond64 = ctx.resolver.resolve_i64(condition_vid, builder.block, ctx.preds, ctx.block_end_values, ctx.vmap, ctx.bb_map)
+            zero64 = ir.IntType(64)(0)
+            cond = builder.icmp_unsigned('!=', cond64, zero64)
+        except Exception:
+            cond = vmap.get(condition_vid, ir.Constant(ir.IntType(1), 0))
+    elif resolver is not None and preds is not None and block_end_values is not None:
         cond64 = resolver.resolve_i64(condition_vid, builder.block, preds, block_end_values, vmap, bb_map)
         zero64 = ir.IntType(64)(0)
         cond = builder.icmp_unsigned('!=', cond64, zero64)

src/llvm_py/llvm_builder.py

@@ -776,7 +776,7 @@ class NyashLLVMBuilder:
         for inst in term_ops:
             try:
                 import os
-            trace_debug(f"[llvm-py] term op: {inst.get('op')} dst={inst.get('dst')} cond={inst.get('cond')}")
+                trace_debug(f"[llvm-py] term op: {inst.get('op')} dst={inst.get('dst')} cond={inst.get('cond')}")
             except Exception:
                 pass
             try:
@@ -950,7 +950,8 @@ class NyashLLVMBuilder:
             self.loop_count += 1
             if not lower_while_loopform(builder, func, cond, body,
                                        self.loop_count, self.vmap, self.bb_map,
-                                       self.resolver, self.preds, self.block_end_values):
+                                       self.resolver, self.preds, self.block_end_values,
+                                       getattr(self, 'ctx', None)):
                 # Fallback to regular while (structured)
                 try:
                     self.resolver._owner_lower_instruction = self.lower_instruction
@@ -975,58 +976,10 @@ class NyashLLVMBuilder:
         except Exception:
             pass
     
-    def _lower_while_regular(self, builder: ir.IRBuilder, inst: Dict[str, Any], func: ir.Function):
-        """Fallback regular while lowering"""
-        # Create basic blocks: cond -> body -> cond, and exit
-        cond_vid = inst.get("cond")
-        body_insts = inst.get("body", [])
-
-        cur_bb = builder.block
-        cond_bb = func.append_basic_block(name=f"while{self.loop_count}_cond")
-        body_bb = func.append_basic_block(name=f"while{self.loop_count}_body")
-        exit_bb = func.append_basic_block(name=f"while{self.loop_count}_exit")
-
-        # Jump from current to cond
-        builder.branch(cond_bb)
-
-        # Cond block
-        cbuild = ir.IRBuilder(cond_bb)
-        try:
-            # Resolve against the condition block to localize dominance
-            cond_val = self.resolver.resolve_i64(cond_vid, cbuild.block, self.preds, self.block_end_values, self.vmap, self.bb_map)
-        except Exception:
-            cond_val = self.vmap.get(cond_vid)
-        if cond_val is None:
-            cond_val = ir.Constant(self.i1, 0)
-        # Normalize to i1
-        if hasattr(cond_val, 'type'):
-            if isinstance(cond_val.type, ir.IntType) and cond_val.type.width == 64:
-                zero64 = ir.Constant(self.i64, 0)
-                cond_val = cbuild.icmp_unsigned('!=', cond_val, zero64, name="while_cond_i1")
-            elif isinstance(cond_val.type, ir.PointerType):
-                nullp = ir.Constant(cond_val.type, None)
-                cond_val = cbuild.icmp_unsigned('!=', cond_val, nullp, name="while_cond_p1")
-            elif isinstance(cond_val.type, ir.IntType) and cond_val.type.width == 1:
-                # already i1
-                pass
-            else:
-                # Fallback: treat as false
-                cond_val = ir.Constant(self.i1, 0)
-        else:
-            cond_val = ir.Constant(self.i1, 0)
-
-        cbuild.cbranch(cond_val, body_bb, exit_bb)
-
-        # Body block
-        bbuild = ir.IRBuilder(body_bb)
-        # Allow nested lowering of body instructions within this block
-        self._lower_instruction_list(bbuild, body_insts, func)
-        # Ensure terminator: if not terminated, branch back to cond
-        if bbuild.block.terminator is None:
-            bbuild.branch(cond_bb)
-
-        # Continue at exit
-        builder.position_at_end(exit_bb)
+    # NOTE: regular while lowering is implemented in
+    # instructions/controlflow/while_.py::lower_while_regular and invoked
+    # from NyashLLVMBuilder.lower_instruction(). This legacy helper is removed
+    # to avoid divergence between two implementations.
 
     def _lower_instruction_list(self, builder: ir.IRBuilder, insts: List[Dict[str, Any]], func: ir.Function):
         """Lower a flat list of instructions using current builder and function."""

src/llvm_py/phi_wiring.py

@@ -5,11 +5,161 @@ PHI wiring helpers
 - finalize_phis: Wire PHI incomings using end-of-block snapshots and resolver
 
 These operate on the NyashLLVMBuilder instance to keep changes minimal.
+
+Refactor note: core responsibilities are split into smaller helpers so they
+can be unit-tested in isolation.
 """
 
-from typing import Dict, List, Any
+from typing import Dict, List, Any, Optional, Tuple
 import llvmlite.ir as ir
 
+# ---- Small helpers (analyzable/testable) ----
+
+def _collect_produced_stringish(blocks: List[Dict[str, Any]]) -> Dict[int, bool]:
+    produced_str: Dict[int, bool] = {}
+    for block_data in blocks:
+        for inst in block_data.get("instructions", []) or []:
+            try:
+                opx = inst.get("op")
+                dstx = inst.get("dst")
+                if dstx is None:
+                    continue
+                is_str = False
+                if opx == "const":
+                    v = inst.get("value", {}) or {}
+                    t = v.get("type")
+                    if t == "string" or (isinstance(t, dict) and t.get("kind") in ("handle", "ptr") and t.get("box_type") == "StringBox"):
+                        is_str = True
+                elif opx in ("binop", "boxcall", "externcall"):
+                    t = inst.get("dst_type")
+                    if isinstance(t, dict) and t.get("kind") == "handle" and t.get("box_type") == "StringBox":
+                        is_str = True
+                if is_str:
+                    produced_str[int(dstx)] = True
+            except Exception:
+                pass
+    return produced_str
+
+def analyze_incomings(blocks: List[Dict[str, Any]]) -> Dict[int, Dict[int, List[Tuple[int, int]]]]:
+    """Return block_phi_incomings map: block_id -> { dst_vid -> [(decl_b, v_src), ...] }"""
+    result: Dict[int, Dict[int, List[Tuple[int, int]]]] = {}
+    for block_data in blocks:
+        bid0 = block_data.get("id", 0)
+        for inst in block_data.get("instructions", []) or []:
+            if inst.get("op") == "phi":
+                try:
+                    dst0 = int(inst.get("dst"))
+                    incoming0 = inst.get("incoming", []) or []
+                except Exception:
+                    dst0 = None; incoming0 = []
+                if dst0 is None:
+                    continue
+                try:
+                    result.setdefault(int(bid0), {})[dst0] = [(int(b), int(v)) for (v, b) in incoming0]
+                except Exception:
+                    pass
+    return result
+
+def ensure_phi(builder, block_id: int, dst_vid: int, bb: ir.Block) -> ir.Instruction:
+    """Ensure a PHI placeholder exists at the block head for dst_vid and return it."""
+    b = ir.IRBuilder(bb)
+    try:
+        b.position_at_start(bb)
+    except Exception:
+        pass
+    # Prefer predeclared PHIs (e.g., from if-merge prepass)
+    predecl = getattr(builder, 'predeclared_ret_phis', {}) if hasattr(builder, 'predeclared_ret_phis') else {}
+    phi = predecl.get((int(block_id), int(dst_vid))) if predecl else None
+    if phi is not None:
+        builder.vmap[dst_vid] = phi
+        return phi
+    # Reuse current if it is a PHI in the correct block
+    cur = builder.vmap.get(dst_vid)
+    try:
+        if cur is not None and hasattr(cur, 'add_incoming') and getattr(getattr(cur, 'basic_block', None), 'name', None) == bb.name:
+            return cur
+    except Exception:
+        pass
+    # Create a new placeholder
+    ph = b.phi(builder.i64, name=f"phi_{dst_vid}")
+    builder.vmap[dst_vid] = ph
+    return ph
+
+def _build_succs(preds: Dict[int, List[int]]) -> Dict[int, List[int]]:
+    succs: Dict[int, List[int]] = {}
+    for to_bid, from_list in (preds or {}).items():
+        for fr in from_list:
+            succs.setdefault(fr, []).append(to_bid)
+    return succs
+
+def _nearest_pred_on_path(succs: Dict[int, List[int]], preds_list: List[int], decl_b: int, target_bid: int) -> Optional[int]:
+    from collections import deque
+    q = deque([decl_b])
+    visited = set([decl_b])
+    parent: Dict[int, Any] = {decl_b: None}
+    while q:
+        cur = q.popleft()
+        if cur == target_bid:
+            par = parent.get(target_bid)
+            return par if par in preds_list else None
+        for nx in succs.get(cur, []):
+            if nx not in visited:
+                visited.add(nx)
+                parent[nx] = cur
+                q.append(nx)
+    return None
+
+def wire_incomings(builder, block_id: int, dst_vid: int, incoming: List[Tuple[int, int]]):
+    """Wire PHI incoming edges for (block_id, dst_vid) using declared (decl_b, v_src) pairs."""
+    bb = builder.bb_map.get(block_id)
+    if bb is None:
+        return
+    phi = ensure_phi(builder, block_id, dst_vid, bb)
+    # Normalize predecessor list
+    preds_raw = [p for p in builder.preds.get(block_id, []) if p != block_id]
+    seen = set()
+    preds_list: List[int] = []
+    for p in preds_raw:
+        if p not in seen:
+            preds_list.append(p)
+            seen.add(p)
+    succs = _build_succs(builder.preds)
+    # Precompute a non-self initial source for self-carry
+    init_src_vid = None
+    for (_bd0, vs0) in incoming:
+        try:
+            vi = int(vs0)
+        except Exception:
+            continue
+        if vi != int(dst_vid):
+            init_src_vid = vi
+            break
+    chosen: Dict[int, ir.Value] = {}
+    for (b_decl, v_src) in incoming:
+        try:
+            bd = int(b_decl); vs = int(v_src)
+        except Exception:
+            continue
+        pred_match = _nearest_pred_on_path(succs, preds_list, bd, block_id)
+        if pred_match is None:
+            continue
+        if vs == int(dst_vid) and init_src_vid is not None:
+            vs = int(init_src_vid)
+        try:
+            val = builder.resolver._value_at_end_i64(vs, pred_match, builder.preds, builder.block_end_values, builder.vmap, builder.bb_map)
+        except Exception:
+            val = None
+        if val is None:
+            val = ir.Constant(builder.i64, 0)
+        chosen[pred_match] = val
+    for pred_bid, val in chosen.items():
+        pred_bb = builder.bb_map.get(pred_bid)
+        if pred_bb is None:
+            continue
+        phi.add_incoming(val, pred_bb)
+
+# ---- Public API (used by llvm_builder) ----
+
 def setup_phi_placeholders(builder, blocks: List[Dict[str, Any]]):
     """Predeclare PHIs and collect incoming metadata for finalize_phis.
 
@@ -18,183 +168,55 @@ def setup_phi_placeholders(builder, blocks: List[Dict[str, Any]]):
     values eagerly to help downstream resolvers choose correct intrinsics.
     """
     try:
-        # Pass A: collect producer stringish hints per value-id
-        produced_str: Dict[int, bool] = {}
-        for block_data in blocks:
-            for inst in block_data.get("instructions", []) or []:
-                try:
-                    opx = inst.get("op")
-                    dstx = inst.get("dst")
-                    if dstx is None:
-                        continue
-                    is_str = False
-                    if opx == "const":
-                        v = inst.get("value", {}) or {}
-                        t = v.get("type")
-                        if t == "string" or (isinstance(t, dict) and t.get("kind") in ("handle","ptr") and t.get("box_type") == "StringBox"):
-                            is_str = True
-                    elif opx in ("binop","boxcall","externcall"):
-                        t = inst.get("dst_type")
-                        if isinstance(t, dict) and t.get("kind") == "handle" and t.get("box_type") == "StringBox":
-                            is_str = True
-                    if is_str:
-                        produced_str[int(dstx)] = True
-                except Exception:
-                    pass
-        # Pass B: materialize PHI placeholders and record incoming metadata
-        builder.block_phi_incomings = {}
+        produced_str = _collect_produced_stringish(blocks)
+        builder.block_phi_incomings = analyze_incomings(blocks)
+        # Materialize placeholders and propagate stringish tags
         for block_data in blocks:
             bid0 = block_data.get("id", 0)
             bb0 = builder.bb_map.get(bid0)
             for inst in block_data.get("instructions", []) or []:
-                if inst.get("op") == "phi":
-                    try:
-                        dst0 = int(inst.get("dst"))
-                        incoming0 = inst.get("incoming", []) or []
-                    except Exception:
-                        dst0 = None; incoming0 = []
-                    if dst0 is None:
-                        continue
-                    # Record incoming metadata for finalize_phis
-                    try:
-                        builder.block_phi_incomings.setdefault(bid0, {})[dst0] = [
-                            (int(b), int(v)) for (v, b) in incoming0
-                        ]
-                    except Exception:
-                        pass
-                    # Ensure placeholder exists at block head
-                    if bb0 is not None:
-                        b0 = ir.IRBuilder(bb0)
-                        try:
-                            b0.position_at_start(bb0)
-                        except Exception:
-                            pass
-                        existing = builder.vmap.get(dst0)
-                        is_phi = False
-                        try:
-                            is_phi = hasattr(existing, 'add_incoming')
-                        except Exception:
-                            is_phi = False
-                        if not is_phi:
-                            ph0 = b0.phi(builder.i64, name=f"phi_{dst0}")
-                            builder.vmap[dst0] = ph0
-                        # Tag propagation: if explicit dst_type marks string or any incoming was produced as string-ish, tag dst
-                        try:
-                            dst_type0 = inst.get("dst_type")
-                            mark_str = isinstance(dst_type0, dict) and dst_type0.get("kind") == "handle" and dst_type0.get("box_type") == "StringBox"
-                            if not mark_str:
-                                for (_b_decl_i, v_src_i) in incoming0:
-                                    try:
-                                        if produced_str.get(int(v_src_i)):
-                                            mark_str = True; break
-                                    except Exception:
-                                        pass
-                            if mark_str and hasattr(builder.resolver, 'mark_string'):
-                                builder.resolver.mark_string(int(dst0))
-                        except Exception:
-                            pass
+                if inst.get("op") != "phi":
+                    continue
+                try:
+                    dst0 = int(inst.get("dst"))
+                    incoming0 = inst.get("incoming", []) or []
+                except Exception:
+                    dst0 = None; incoming0 = []
+                if dst0 is None or bb0 is None:
+                    continue
+                _ = ensure_phi(builder, bid0, dst0, bb0)
+                # Tag propagation
+                try:
+                    dst_type0 = inst.get("dst_type")
+                    mark_str = isinstance(dst_type0, dict) and dst_type0.get("kind") == "handle" and dst_type0.get("box_type") == "StringBox"
+                    if not mark_str:
+                        for (_b_decl_i, v_src_i) in incoming0:
+                            try:
+                                if produced_str.get(int(v_src_i)):
+                                    mark_str = True; break
+                            except Exception:
+                                pass
+                    if mark_str and hasattr(builder.resolver, 'mark_string'):
+                        builder.resolver.mark_string(int(dst0))
+                except Exception:
+                    pass
+                # Definition hint: PHI defines dst in this block
+                try:
+                    builder.def_blocks.setdefault(int(dst0), set()).add(int(bid0))
+                except Exception:
+                    pass
+        # Sync to resolver
+        try:
+            builder.resolver.block_phi_incomings = builder.block_phi_incomings
+        except Exception:
+            pass
     except Exception:
         pass
 
 def finalize_phis(builder):
     """Finalize PHIs declared in JSON by wiring incoming edges at block heads.
-    Uses resolver._value_at_end_i64 to materialize values at predecessor ends,
-    ensuring casts/boxing are inserted in predecessor blocks (dominance-safe)."""
-    # Build succ map for nearest-predecessor mapping
-    succs: Dict[int, List[int]] = {}
-    for to_bid, from_list in (builder.preds or {}).items():
-        for fr in from_list:
-            succs.setdefault(fr, []).append(to_bid)
+    Uses resolver._value_at_end_i64 to materialize values at predecessor ends.
+    """
     for block_id, dst_map in (getattr(builder, 'block_phi_incomings', {}) or {}).items():
-        bb = builder.bb_map.get(block_id)
-        if bb is None:
-            continue
-        b = ir.IRBuilder(bb)
-        try:
-            b.position_at_start(bb)
-        except Exception:
-            pass
         for dst_vid, incoming in (dst_map or {}).items():
-            # Ensure placeholder exists at block head
-            # Prefer predeclared ret-phi when available and force using it.
-            predecl = getattr(builder, 'predeclared_ret_phis', {}) if hasattr(builder, 'predeclared_ret_phis') else {}
-            phi = predecl.get((int(block_id), int(dst_vid))) if predecl else None
-            if phi is not None:
-                builder.vmap[dst_vid] = phi
-            else:
-                phi = builder.vmap.get(dst_vid)
-                need_local_phi = False
-                try:
-                    if not (phi is not None and hasattr(phi, 'add_incoming')):
-                        need_local_phi = True
-                    else:
-                        bb_of_phi = getattr(getattr(phi, 'basic_block', None), 'name', None)
-                        if bb_of_phi != bb.name:
-                            need_local_phi = True
-                except Exception:
-                    need_local_phi = True
-                if need_local_phi:
-                    phi = b.phi(builder.i64, name=f"phi_{dst_vid}")
-                    builder.vmap[dst_vid] = phi
-            # Wire incoming per CFG predecessor; map src_vid when provided
-            preds_raw = [p for p in builder.preds.get(block_id, []) if p != block_id]
-            # Deduplicate while preserving order
-            seen = set()
-            preds_list: List[int] = []
-            for p in preds_raw:
-                if p not in seen:
-                    preds_list.append(p)
-                    seen.add(p)
-            # Helper: find the nearest immediate predecessor on a path decl_b -> ... -> block_id
-            def nearest_pred_on_path(decl_b: int):
-                from collections import deque
-                q = deque([decl_b])
-                visited = set([decl_b])
-                parent: Dict[int, Any] = {decl_b: None}
-                while q:
-                    cur = q.popleft()
-                    if cur == block_id:
-                        par = parent.get(block_id)
-                        return par if par in preds_list else None
-                    for nx in succs.get(cur, []):
-                        if nx not in visited:
-                            visited.add(nx)
-                            parent[nx] = cur
-                            q.append(nx)
-                return None
-            # Precompute a non-self initial source (if present) to use for self-carry cases
-            init_src_vid = None
-            for (b_decl0, v_src0) in incoming:
-                try:
-                    vs0 = int(v_src0)
-                except Exception:
-                    continue
-                if vs0 != int(dst_vid):
-                    init_src_vid = vs0
-                    break
-            # Pre-resolve declared incomings to nearest immediate predecessors
-            chosen: Dict[int, ir.Value] = {}
-            for (b_decl, v_src) in incoming:
-                try:
-                    bd = int(b_decl); vs = int(v_src)
-                except Exception:
-                    continue
-                pred_match = nearest_pred_on_path(bd)
-                if pred_match is None:
-                    continue
-                if vs == int(dst_vid) and init_src_vid is not None:
-                    vs = int(init_src_vid)
-                try:
-                    val = builder.resolver._value_at_end_i64(vs, pred_match, builder.preds, builder.block_end_values, builder.vmap, builder.bb_map)
-                except Exception:
-                    val = None
-                if val is None:
-                    # As a last resort, zero
-                    val = ir.Constant(builder.i64, 0)
-                chosen[pred_match] = val
-            # Finally add incomings
-            for pred_bid, val in chosen.items():
-                pred_bb = builder.bb_map.get(pred_bid)
-                if pred_bb is None:
-                    continue
-                phi.add_incoming(val, pred_bb)
+            wire_incomings(builder, int(block_id), int(dst_vid), incoming)

src/llvm_py/tests/test_phi_wiring.py

@@ -0,0 +1,65 @@
+"""
+Unit tests for phi_wiring helpers
+
+These tests construct a minimal function with two blocks and a PHI in the
+second block. We verify that placeholders are created and incoming edges
+are wired from the correct predecessor, using end-of-block snapshots.
+"""
+
+import sys
+from pathlib import Path
+
+# Ensure 'src' is importable when running this test directly
+TEST_DIR = Path(__file__).resolve().parent
+PKG_DIR = TEST_DIR.parent  # src/llvm_py
+ROOT = PKG_DIR.parent      # src
+if str(ROOT) not in sys.path:
+    sys.path.insert(0, str(ROOT))
+if str(PKG_DIR) not in sys.path:
+    sys.path.insert(0, str(PKG_DIR))
+
+import llvmlite.ir as ir  # type: ignore
+
+from phi_wiring import setup_phi_placeholders, finalize_phis  # type: ignore
+import llvm_builder  # type: ignore
+
+
+def _simple_mir_with_phi():
+    """
+    Build a minimal MIR JSON that compiles to:
+      bb0: const v1=42; jump bb1
+      bb1: phi v2=[(bb0,v1)] ; ret v2
+    """
+    return {
+        "functions": [
+            {
+                "name": "main",
+                "params": [],
+                "blocks": [
+                    {"id": 0, "instructions": [
+                        {"op": "const", "dst": 1, "value": {"type": "int", "value": 42}},
+                        {"op": "jump", "target": 1}
+                    ]},
+                    {"id": 1, "instructions": [
+                        {"op": "phi", "dst": 2, "incoming": [[1, 0]]},
+                        {"op": "ret", "value": 2}
+                    ]}
+                ]
+            }
+        ]
+    }
+
+
+def test_phi_placeholders_and_finalize_basic():
+    mir = _simple_mir_with_phi()
+    b = llvm_builder.NyashLLVMBuilder()
+    # Build once to create function, blocks, preds; stop before finalize by calling internals like lower_function
+    reader_functions = mir["functions"]
+    assert reader_functions
+    b.lower_function(reader_functions[0])
+    # After lowering a function, finalize_phis is already called at the end of lower_function.
+    # Verify via IR text that a PHI exists in bb1 with an incoming from bb0.
+    ir_text = str(b.module)
+    assert 'bb1' in ir_text
+    assert 'phi  i64' in ir_text
+    assert '[0, %"bb0"]' in ir_text or '[ i64 0, %"bb0"]' in ir_text

src/mir/optimizer.rs

@@ -105,7 +105,7 @@ impl MirOptimizer {
 
         // Pass 7 (optional): Core-13 pure normalization
         if crate::config::env::mir_core13_pure() {
-            stats.merge(self.normalize_pure_core13(module));
+            stats.merge(crate::mir::optimizer_passes::normalize_core13_pure::normalize_pure_core13(self, module));
         }
 
         if self.debug {
@@ -147,200 +147,7 @@ impl MirOptimizer {
     ///     Neg x    => BinOp(Sub, Const 0, x)
     ///     Not x    => Compare(Eq, x, Const false)
     ///     BitNot x => BinOp(BitXor, x, Const(-1))
-    fn normalize_pure_core13(&mut self, module: &mut MirModule) -> OptimizationStats {
-        use super::instruction::ConstValue;
-        use super::{BinaryOp, CompareOp, MirInstruction as I};
-        let mut stats = OptimizationStats::new();
-        for (_fname, function) in &mut module.functions {
-            for (_bb, block) in &mut function.blocks {
-                let mut out: Vec<I> = Vec::with_capacity(block.instructions.len() + 8);
-                let old = std::mem::take(&mut block.instructions);
-                for inst in old.into_iter() {
-                    match inst {
-                        I::Load { dst, ptr } => {
-                            out.push(I::ExternCall {
-                                dst: Some(dst),
-                                iface_name: "env.local".to_string(),
-                                method_name: "get".to_string(),
-                                args: vec![ptr],
-                                effects: super::EffectMask::READ,
-                            });
-                            stats.intrinsic_optimizations += 1;
-                        }
-                        I::Store { value, ptr } => {
-                            out.push(I::ExternCall {
-                                dst: None,
-                                iface_name: "env.local".to_string(),
-                                method_name: "set".to_string(),
-                                args: vec![ptr, value],
-                                effects: super::EffectMask::WRITE,
-                            });
-                            stats.intrinsic_optimizations += 1;
-                        }
-                        I::NewBox {
-                            dst,
-                            box_type,
-                            mut args,
-                        } => {
-                            // prepend type name as Const String
-                            let ty_id = super::ValueId::new(function.next_value_id);
-                            function.next_value_id += 1;
-                            out.push(I::Const {
-                                dst: ty_id,
-                                value: ConstValue::String(box_type),
-                            });
-                            let mut call_args = Vec::with_capacity(1 + args.len());
-                            call_args.push(ty_id);
-                            call_args.append(&mut args);
-                            out.push(I::ExternCall {
-                                dst: Some(dst),
-                                iface_name: "env.box".to_string(),
-                                method_name: "new".to_string(),
-                                args: call_args,
-                                effects: super::EffectMask::PURE, // constructor is logically alloc; conservatively PURE here
-                            });
-                            stats.intrinsic_optimizations += 1;
-                        }
-                        I::UnaryOp { dst, op, operand } => {
-                            match op {
-                                super::UnaryOp::Neg => {
-                                    let zero = super::ValueId::new(function.next_value_id);
-                                    function.next_value_id += 1;
-                                    out.push(I::Const {
-                                        dst: zero,
-                                        value: ConstValue::Integer(0),
-                                    });
-                                    out.push(I::BinOp {
-                                        dst,
-                                        op: BinaryOp::Sub,
-                                        lhs: zero,
-                                        rhs: operand,
-                                    });
-                                }
-                                super::UnaryOp::Not => {
-                                    let f = super::ValueId::new(function.next_value_id);
-                                    function.next_value_id += 1;
-                                    out.push(I::Const {
-                                        dst: f,
-                                        value: ConstValue::Bool(false),
-                                    });
-                                    out.push(I::Compare {
-                                        dst,
-                                        op: CompareOp::Eq,
-                                        lhs: operand,
-                                        rhs: f,
-                                    });
-                                }
-                                super::UnaryOp::BitNot => {
-                                    let all1 = super::ValueId::new(function.next_value_id);
-                                    function.next_value_id += 1;
-                                    out.push(I::Const {
-                                        dst: all1,
-                                        value: ConstValue::Integer(-1),
-                                    });
-                                    out.push(I::BinOp {
-                                        dst,
-                                        op: BinaryOp::BitXor,
-                                        lhs: operand,
-                                        rhs: all1,
-                                    });
-                                }
-                            }
-                            stats.intrinsic_optimizations += 1;
-                        }
-                        other => out.push(other),
-                    }
-                }
-                block.instructions = out;
-                if let Some(term) = block.terminator.take() {
-                    block.terminator = Some(match term {
-                        I::Load { dst, ptr } => I::ExternCall {
-                            dst: Some(dst),
-                            iface_name: "env.local".to_string(),
-                            method_name: "get".to_string(),
-                            args: vec![ptr],
-                            effects: super::EffectMask::READ,
-                        },
-                        I::Store { value, ptr } => I::ExternCall {
-                            dst: None,
-                            iface_name: "env.local".to_string(),
-                            method_name: "set".to_string(),
-                            args: vec![ptr, value],
-                            effects: super::EffectMask::WRITE,
-                        },
-                        I::NewBox {
-                            dst,
-                            box_type,
-                            mut args,
-                        } => {
-                            let ty_id = super::ValueId::new(function.next_value_id);
-                            function.next_value_id += 1;
-                            block.instructions.push(I::Const {
-                                dst: ty_id,
-                                value: ConstValue::String(box_type),
-                            });
-                            let mut call_args = Vec::with_capacity(1 + args.len());
-                            call_args.push(ty_id);
-                            call_args.append(&mut args);
-                            I::ExternCall {
-                                dst: Some(dst),
-                                iface_name: "env.box".to_string(),
-                                method_name: "new".to_string(),
-                                args: call_args,
-                                effects: super::EffectMask::PURE,
-                            }
-                        }
-                        I::UnaryOp { dst, op, operand } => match op {
-                            super::UnaryOp::Neg => {
-                                let zero = super::ValueId::new(function.next_value_id);
-                                function.next_value_id += 1;
-                                block.instructions.push(I::Const {
-                                    dst: zero,
-                                    value: ConstValue::Integer(0),
-                                });
-                                I::BinOp {
-                                    dst,
-                                    op: BinaryOp::Sub,
-                                    lhs: zero,
-                                    rhs: operand,
-                                }
-                            }
-                            super::UnaryOp::Not => {
-                                let f = super::ValueId::new(function.next_value_id);
-                                function.next_value_id += 1;
-                                block.instructions.push(I::Const {
-                                    dst: f,
-                                    value: ConstValue::Bool(false),
-                                });
-                                I::Compare {
-                                    dst,
-                                    op: CompareOp::Eq,
-                                    lhs: operand,
-                                    rhs: f,
-                                }
-                            }
-                            super::UnaryOp::BitNot => {
-                                let all1 = super::ValueId::new(function.next_value_id);
-                                function.next_value_id += 1;
-                                block.instructions.push(I::Const {
-                                    dst: all1,
-                                    value: ConstValue::Integer(-1),
-                                });
-                                I::BinOp {
-                                    dst,
-                                    op: BinaryOp::BitXor,
-                                    lhs: operand,
-                                    rhs: all1,
-                                }
-                            }
-                        },
-                        other => other,
-                    });
-                }
-            }
-        }
-        stats
-    }
+    // normalize_pure_core13 moved to optimizer_passes::normalize_core13_pure
 
     /// Eliminate dead code in a single function
     fn eliminate_dead_code_in_function(&mut self, function: &mut MirFunction) -> usize {

src/mir/optimizer_passes/mod.rs

@@ -3,3 +3,5 @@ pub mod diagnostics;
 pub mod intrinsics;
 pub mod normalize;
 pub mod reorder;
+pub mod normalize_core13_pure;
+pub mod normalize_legacy_all;

src/mir/optimizer_passes/normalize_core13_pure.rs

@@ -0,0 +1,145 @@
+use crate::mir::optimizer::MirOptimizer;
+use crate::mir::optimizer_stats::OptimizationStats;
+use crate::mir::{BinaryOp, CompareOp, EffectMask, MirInstruction as I, MirModule, MirType, ValueId};
+
+/// Core-13 "pure" normalization: rewrite a few non-13 ops to allowed forms.
+/// - Load(dst, ptr)  => ExternCall(Some dst, env.local.get, [ptr])
+/// - Store(val, ptr) => ExternCall(None, env.local.set, [ptr, val])
+/// - NewBox(dst, T, args...) => ExternCall(Some dst, env.box.new, [Const String(T), args...])
+/// - UnaryOp:
+///     Neg x    => BinOp(Sub, Const 0, x)
+///     Not x    => Compare(Eq, x, Const false)
+///     BitNot x => BinOp(BitXor, x, Const(-1))
+pub fn normalize_pure_core13(_opt: &mut MirOptimizer, module: &mut MirModule) -> OptimizationStats {
+    use crate::mir::instruction::ConstValue;
+    let mut stats = OptimizationStats::new();
+    for (_fname, function) in &mut module.functions {
+        for (_bb, block) in &mut function.blocks {
+            let mut out: Vec<I> = Vec::with_capacity(block.instructions.len() + 8);
+            let old = std::mem::take(&mut block.instructions);
+            for inst in old.into_iter() {
+                match inst {
+                    I::Load { dst, ptr } => {
+                        out.push(I::ExternCall {
+                            dst: Some(dst),
+                            iface_name: "env.local".to_string(),
+                            method_name: "get".to_string(),
+                            args: vec![ptr],
+                            effects: EffectMask::READ,
+                        });
+                        stats.intrinsic_optimizations += 1;
+                    }
+                    I::Store { value, ptr } => {
+                        out.push(I::ExternCall {
+                            dst: None,
+                            iface_name: "env.local".to_string(),
+                            method_name: "set".to_string(),
+                            args: vec![ptr, value],
+                            effects: EffectMask::WRITE,
+                        });
+                        stats.intrinsic_optimizations += 1;
+                    }
+                    I::NewBox { dst, box_type, mut args } => {
+                        // prepend type name as Const String
+                        let ty_id = ValueId::new(function.next_value_id);
+                        function.next_value_id += 1;
+                        out.push(I::Const { dst: ty_id, value: ConstValue::String(box_type) });
+                        let mut call_args = Vec::with_capacity(1 + args.len());
+                        call_args.push(ty_id);
+                        call_args.append(&mut args);
+                        out.push(I::ExternCall {
+                            dst: Some(dst),
+                            iface_name: "env.box".to_string(),
+                            method_name: "new".to_string(),
+                            args: call_args,
+                            effects: EffectMask::PURE, // constructor is logically alloc; conservatively PURE here
+                        });
+                        stats.intrinsic_optimizations += 1;
+                    }
+                    I::UnaryOp { dst, op, operand } => {
+                        match op {
+                            crate::mir::UnaryOp::Neg => {
+                                let zero = ValueId::new(function.next_value_id);
+                                function.next_value_id += 1;
+                                out.push(I::Const { dst: zero, value: ConstValue::Integer(0) });
+                                out.push(I::BinOp { dst, op: BinaryOp::Sub, lhs: zero, rhs: operand });
+                            }
+                            crate::mir::UnaryOp::Not => {
+                                let f = ValueId::new(function.next_value_id);
+                                function.next_value_id += 1;
+                                out.push(I::Const { dst: f, value: ConstValue::Bool(false) });
+                                out.push(I::Compare { dst, op: CompareOp::Eq, lhs: operand, rhs: f });
+                            }
+                            crate::mir::UnaryOp::BitNot => {
+                                let all1 = ValueId::new(function.next_value_id);
+                                function.next_value_id += 1;
+                                out.push(I::Const { dst: all1, value: ConstValue::Integer(-1) });
+                                out.push(I::BinOp { dst, op: BinaryOp::BitXor, lhs: operand, rhs: all1 });
+                            }
+                        }
+                        stats.intrinsic_optimizations += 1;
+                    }
+                    other => out.push(other),
+                }
+            }
+            block.instructions = out;
+
+            if let Some(term) = block.terminator.take() {
+                block.terminator = Some(match term {
+                    I::Load { dst, ptr } => I::ExternCall {
+                        dst: Some(dst),
+                        iface_name: "env.local".to_string(),
+                        method_name: "get".to_string(),
+                        args: vec![ptr],
+                        effects: EffectMask::READ,
+                    },
+                    I::Store { value, ptr } => I::ExternCall {
+                        dst: None,
+                        iface_name: "env.local".to_string(),
+                        method_name: "set".to_string(),
+                        args: vec![ptr, value],
+                        effects: EffectMask::WRITE,
+                    },
+                    I::NewBox { dst, box_type, mut args } => {
+                        let ty_id = ValueId::new(function.next_value_id);
+                        function.next_value_id += 1;
+                        block.instructions.push(I::Const { dst: ty_id, value: ConstValue::String(box_type) });
+                        let mut call_args = Vec::with_capacity(1 + args.len());
+                        call_args.push(ty_id);
+                        call_args.append(&mut args);
+                        I::ExternCall {
+                            dst: Some(dst),
+                            iface_name: "env.box".to_string(),
+                            method_name: "new".to_string(),
+                            args: call_args,
+                            effects: EffectMask::PURE,
+                        }
+                    }
+                    I::UnaryOp { dst, op, operand } => match op {
+                        crate::mir::UnaryOp::Neg => {
+                            let zero = ValueId::new(function.next_value_id);
+                            function.next_value_id += 1;
+                            block.instructions.push(I::Const { dst: zero, value: ConstValue::Integer(0) });
+                            I::BinOp { dst, op: BinaryOp::Sub, lhs: zero, rhs: operand }
+                        }
+                        crate::mir::UnaryOp::Not => {
+                            let f = ValueId::new(function.next_value_id);
+                            function.next_value_id += 1;
+                            block.instructions.push(I::Const { dst: f, value: ConstValue::Bool(false) });
+                            I::Compare { dst, op: CompareOp::Eq, lhs: operand, rhs: f }
+                        }
+                        crate::mir::UnaryOp::BitNot => {
+                            let all1 = ValueId::new(function.next_value_id);
+                            function.next_value_id += 1;
+                            block.instructions.push(I::Const { dst: all1, value: ConstValue::Integer(-1) });
+                            I::BinOp { dst, op: BinaryOp::BitXor, lhs: operand, rhs: all1 }
+                        }
+                    },
+                    other => other,
+                });
+            }
+        }
+    }
+    stats
+}
+

src/mir/optimizer_passes/normalize_legacy_all.rs

@@ -0,0 +1,8 @@
+use crate::mir::optimizer::MirOptimizer;
+use crate::mir::optimizer_stats::OptimizationStats;
+
+/// Delegate: legacy normalization (moved from optimizer.rs)
+pub fn normalize_legacy_instructions(opt: &mut MirOptimizer, module: &mut crate::mir::MirModule) -> OptimizationStats {
+    crate::mir::optimizer_passes::normalize::normalize_legacy_instructions(opt, module)
+}
+

src/runner/mod.rs

@@ -143,6 +143,12 @@ impl NyashRunner {
         if self.config.cli_verbose {
             std::env::set_var("NYASH_CLI_VERBOSE", "1");
         }
+        // GC mode forwarding: map CLI --gc to NYASH_GC_MODE for downstream runtimes
+        if let Some(ref m) = self.config.gc_mode {
+            if !m.trim().is_empty() {
+                std::env::set_var("NYASH_GC_MODE", m);
+            }
+        }
         // Script-level env directives (special comments) — parse early
         // Supported:
         //   // @env KEY=VALUE

src/runner/modes/common.rs

@@ -11,8 +11,6 @@ use std::thread::sleep;
 use crate::runner::pipeline::{suggest_in_base, resolve_using_target};
 use crate::runner::trace::cli_verbose;
 use crate::cli_v;
-use crate::runner::trace::cli_verbose;
-use crate::cli_v;
 
 // (moved) suggest_in_base is now in runner/pipeline.rs
 
@@ -131,97 +129,13 @@ impl NyashRunner {
 
     /// Helper: run PyVM harness over a MIR module, returning the exit code
     fn run_pyvm_harness(&self, module: &nyash_rust::mir::MirModule, tag: &str) -> Result<i32, String> {
-        let py3 = which::which("python3").map_err(|e| format!("python3 not found: {}", e))?;
-        let runner = std::path::Path::new("tools/pyvm_runner.py");
-        if !runner.exists() { return Err(format!("PyVM runner not found: {}", runner.display())); }
-        let tmp_dir = std::path::Path::new("tmp");
-        let _ = std::fs::create_dir_all(tmp_dir);
-        let mir_json_path = tmp_dir.join("nyash_pyvm_mir.json");
-        crate::runner::mir_json_emit::emit_mir_json_for_harness_bin(module, &mir_json_path)
-            .map_err(|e| format!("PyVM MIR JSON emit error: {}", e))?;
-        cli_v!("[ny-compiler] using PyVM ({} ) → {}", tag, mir_json_path.display());
-        // Determine entry function hint (prefer Main.main if present)
-        let entry = if module.functions.contains_key("Main.main") { "Main.main" }
-                    else if module.functions.contains_key("main") { "main" } else { "Main.main" };
-        let status = std::process::Command::new(py3)
-            .args([
-                runner.to_string_lossy().as_ref(),
-                "--in",
-                &mir_json_path.display().to_string(),
-                "--entry",
-                entry,
-            ])
-            .status()
-            .map_err(|e| format!("spawn pyvm: {}", e))?;
-        let code = status.code().unwrap_or(1);
-        if !status.success() { cli_v!("❌ PyVM ({}) failed (status={})", tag, code); }
-        Ok(code)
+        super::common_util::pyvm::run_pyvm_harness(module, tag)
     }
 
     /// Helper: try external selfhost compiler EXE to parse Ny -> JSON v0 and return MIR module
     /// Returns Some(module) on success, None on failure (timeout/invalid output/missing exe)
     fn exe_try_parse_json_v0(&self, filename: &str, timeout_ms: u64) -> Option<nyash_rust::mir::MirModule> {
-        // Resolve parser EXE path
-        let exe_path = if let Ok(p) = std::env::var("NYASH_NY_COMPILER_EXE_PATH") {
-            std::path::PathBuf::from(p)
-        } else {
-            let mut p = std::path::PathBuf::from("dist/nyash_compiler");
-            #[cfg(windows)]
-            { p.push("nyash_compiler.exe"); }
-            #[cfg(not(windows))]
-            { p.push("nyash_compiler"); }
-            if !p.exists() {
-                if let Ok(w) = which::which("nyash_compiler") { w } else { p }
-            } else { p }
-        };
-        if !exe_path.exists() { cli_v!("[ny-compiler] exe not found at {}", exe_path.display()); return None; }
-
-        // Build command
-        let mut cmd = std::process::Command::new(&exe_path);
-        cmd.arg(filename);
-        if crate::config::env::ny_compiler_min_json() { cmd.arg("--min-json"); }
-        if crate::config::env::selfhost_read_tmp() { cmd.arg("--read-tmp"); }
-        if let Some(raw) = crate::config::env::ny_compiler_child_args() { for tok in raw.split_whitespace() { cmd.arg(tok); } }
-        let mut cmd = cmd.stdout(Stdio::piped()).stderr(Stdio::piped());
-        let mut child = match cmd.spawn() { Ok(c) => c, Err(e) => { eprintln!("[ny-compiler] exe spawn failed: {}", e); return None; } };
-        let mut ch_stdout = child.stdout.take();
-        let mut ch_stderr = child.stderr.take();
-        let start = Instant::now();
-        let mut timed_out = false;
-        loop {
-            match child.try_wait() {
-                Ok(Some(_)) => break,
-                Ok(None) => {
-                    if start.elapsed() >= Duration::from_millis(timeout_ms) { let _ = child.kill(); let _ = child.wait(); timed_out = true; break; }
-                    sleep(Duration::from_millis(10));
-                }
-                Err(e) => { eprintln!("[ny-compiler] exe wait error: {}", e); return None; }
-            }
-        }
-        let mut out_buf = Vec::new();
-        let mut err_buf = Vec::new();
-        if let Some(mut s) = ch_stdout { let _ = s.read_to_end(&mut out_buf); }
-        if let Some(mut s) = ch_stderr { let _ = s.read_to_end(&mut err_buf); }
-        if timed_out {
-            let head = String::from_utf8_lossy(&out_buf).chars().take(200).collect::<String>();
-            eprintln!("[ny-compiler] exe timeout after {} ms; stdout(head)='{}'", timeout_ms, head.replace('\n', "\\n"));
-            return None;
-        }
-        let stdout = match String::from_utf8(out_buf) { Ok(s) => s, Err(_) => String::new() };
-        let mut json_line = String::new();
-        for line in stdout.lines() { let t = line.trim(); if t.starts_with('{') && t.contains("\"version\"") && t.contains("\"kind\"") { json_line = t.to_string(); break; } }
-        if json_line.is_empty() {
-            if cli_verbose() {
-                let head: String = stdout.chars().take(200).collect();
-                let errh: String = String::from_utf8_lossy(&err_buf).chars().take(200).collect();
-                cli_v!("[ny-compiler] exe produced no JSON; stdout(head)='{}' stderr(head)='{}'", head.replace('\n', "\\n"), errh.replace('\n', "\\n"));
-            }
-            return None;
-        }
-        match json_v0_bridge::parse_json_v0_to_module(&json_line) {
-            Ok(module) => Some(module),
-            Err(e) => { eprintln!("[ny-compiler] JSON parse failed (exe): {}", e); None }
-        }
+        super::common_util::selfhost_exe::exe_try_parse_json_v0(filename, timeout_ms)
     }
 
     /// Phase-15.3: Attempt Ny compiler pipeline (Ny -> JSON v0 via Ny program), then execute MIR
@@ -324,38 +238,22 @@ impl NyashRunner {
                 if crate::config::env::selfhost_read_tmp() { cmd.arg("--read-tmp"); }
                 if let Some(raw) = crate::config::env::ny_compiler_child_args() { for tok in raw.split_whitespace() { cmd.arg(tok); } }
                 let timeout_ms: u64 = crate::config::env::ny_compiler_timeout_ms();
-                let mut cmd = cmd.stdout(Stdio::piped()).stderr(Stdio::piped());
-                let mut child = match cmd.spawn() { Ok(c) => c, Err(e) => { eprintln!("[ny-compiler] exe spawn failed: {}", e); return false; } };
-                let mut ch_stdout = child.stdout.take();
-                let mut ch_stderr = child.stderr.take();
-                let start = Instant::now();
-                let mut timed_out = false;
-                loop {
-                    match child.try_wait() {
-                        Ok(Some(_status)) => { break; }
-                        Ok(None) => {
-                            if start.elapsed() >= Duration::from_millis(timeout_ms) { let _ = child.kill(); let _ = child.wait(); timed_out = true; break; }
-                            sleep(Duration::from_millis(10));
-                        }
-                        Err(e) => { eprintln!("[ny-compiler] exe wait error: {}", e); return false; }
-                    }
-                }
-                let mut out_buf = Vec::new();
-                let mut err_buf = Vec::new();
-                if let Some(mut s) = ch_stdout { let _ = s.read_to_end(&mut out_buf); }
-                if let Some(mut s) = ch_stderr { let _ = s.read_to_end(&mut err_buf); }
-                if timed_out {
-                    let head = String::from_utf8_lossy(&out_buf).chars().take(200).collect::<String>();
+                let out = match super::common_util::io::spawn_with_timeout(cmd, timeout_ms) {
+                    Ok(o) => o,
+                    Err(e) => { eprintln!("[ny-compiler] exe spawn failed: {}", e); return false; }
+                };
+                if out.timed_out {
+                    let head = String::from_utf8_lossy(&out.stdout).chars().take(200).collect::<String>();
                     eprintln!("[ny-compiler] exe timeout after {} ms; stdout(head)='{}'", timeout_ms, head.replace('\n', "\\n"));
                     return false;
                 }
-                let stdout = match String::from_utf8(out_buf) { Ok(s) => s, Err(_) => String::new() };
+                let stdout = match String::from_utf8(out.stdout) { Ok(s) => s, Err(_) => String::new() };
                 let mut json_line = String::new();
                 for line in stdout.lines() { let t = line.trim(); if t.starts_with('{') && t.contains("\"version\"") && t.contains("\"kind\"") { json_line = t.to_string(); break; } }
                 if json_line.is_empty() {
                     if crate::config::env::cli_verbose() {
                         let head: String = stdout.chars().take(200).collect();
-                        let errh: String = String::from_utf8_lossy(&err_buf).chars().take(200).collect();
+                        let errh: String = String::from_utf8_lossy(&out.stderr).chars().take(200).collect();
                         eprintln!("[ny-compiler] exe produced no JSON; stdout(head)='{}' stderr(head)='{}'", head.replace('\n', "\\n"), errh.replace('\n', "\\n"));
                     }
                     return false;
@@ -450,40 +348,15 @@ impl NyashRunner {
             .ok()
             .and_then(|s| s.parse::<u64>().ok())
             .unwrap_or(2000);
-        let mut cmd = cmd.stdout(Stdio::piped()).stderr(Stdio::piped());
-        let mut child = match cmd.spawn() {
-            Ok(c) => c,
+        let out = match super::common_util::io::spawn_with_timeout(cmd, timeout_ms) {
+            Ok(o) => o,
             Err(e) => { eprintln!("[ny-compiler] spawn failed: {}", e); return false; }
         };
-        let mut ch_stdout = child.stdout.take();
-        let mut ch_stderr = child.stderr.take();
-        let start = Instant::now();
-        let mut timed_out = false;
-        loop {
-            match child.try_wait() {
-                Ok(Some(_status)) => { break; }
-                Ok(None) => {
-                    if start.elapsed() >= Duration::from_millis(timeout_ms) {
-                        let _ = child.kill();
-                        let _ = child.wait();
-                        timed_out = true;
-                        break;
-                    }
-                    sleep(Duration::from_millis(10));
-                }
-                Err(e) => { eprintln!("[ny-compiler] wait error: {}", e); return false; }
-            }
-        }
-        // Collect any available output
-        let mut out_buf = Vec::new();
-        let mut err_buf = Vec::new();
-        if let Some(mut s) = ch_stdout { let _ = s.read_to_end(&mut out_buf); }
-        if let Some(mut s) = ch_stderr { let _ = s.read_to_end(&mut err_buf); }
-        if timed_out {
-            let head = String::from_utf8_lossy(&out_buf).chars().take(200).collect::<String>();
+        if out.timed_out {
+            let head = String::from_utf8_lossy(&out.stdout).chars().take(200).collect::<String>();
             eprintln!("[ny-compiler] child timeout after {} ms; stdout(head)='{}'", timeout_ms, head.replace('\n', "\\n"));
         }
-        let stdout = match String::from_utf8(out_buf) { Ok(s) => s, Err(_) => String::new() };
+        let stdout = match String::from_utf8(out.stdout.clone()) { Ok(s) => s, Err(_) => String::new() };
         if timed_out {
             // Fall back path will be taken below when json_line remains empty
         } else if let Ok(s) = String::from_utf8(err_buf.clone()) {

src/runner/modes/common_util/io.rs

@@ -0,0 +1,55 @@
+use std::io::Read;
+use std::process::{Command, Stdio};
+use std::thread::sleep;
+use std::time::{Duration, Instant};
+
+pub struct ChildOutput {
+    pub stdout: Vec<u8>,
+    pub stderr: Vec<u8>,
+    pub status_ok: bool,
+    pub exit_code: Option<i32>,
+    pub timed_out: bool,
+}
+
+/// Spawn command with timeout (ms), capture stdout/stderr, and return ChildOutput.
+pub fn spawn_with_timeout(mut cmd: Command, timeout_ms: u64) -> std::io::Result<ChildOutput> {
+    let mut cmd = cmd.stdout(Stdio::piped()).stderr(Stdio::piped());
+    let mut child = cmd.spawn()?;
+    let mut ch_stdout = child.stdout.take();
+    let mut ch_stderr = child.stderr.take();
+    let start = Instant::now();
+    let mut timed_out = false;
+    let mut exit_status: Option<std::process::ExitStatus> = None;
+    loop {
+        match child.try_wait()? {
+            Some(status) => { exit_status = Some(status); break },
+            None => {
+                if start.elapsed() >= Duration::from_millis(timeout_ms) {
+                    let _ = child.kill();
+                    let _ = child.wait();
+                    timed_out = true;
+                    break;
+                }
+                sleep(Duration::from_millis(10));
+            }
+        }
+    }
+    let mut out_buf = Vec::new();
+    let mut err_buf = Vec::new();
+    if let Some(mut s) = ch_stdout {
+        let _ = s.read_to_end(&mut out_buf);
+    }
+    if let Some(mut s) = ch_stderr {
+        let _ = s.read_to_end(&mut err_buf);
+    }
+    let (status_ok, exit_code) = if let Some(st) = exit_status {
+        (st.success(), st.code())
+    } else { (false, None) };
+    Ok(ChildOutput {
+        stdout: out_buf,
+        stderr: err_buf,
+        status_ok,
+        exit_code,
+        timed_out,
+    })
+}

src/runner/modes/common_util/mod.rs

@@ -0,0 +1,9 @@
+/*!
+ * Shared helpers for runner/modes/common.rs
+ *
+ * Minimal extraction to reduce duplication and prepare for full split.
+ */
+
+pub mod pyvm;
+pub mod selfhost_exe;
+pub mod io;

src/runner/modes/common_util/pyvm.rs

@@ -0,0 +1,39 @@
+use std::process::Stdio;
+
+/// Run PyVM harness over a MIR module, returning the exit code
+pub fn run_pyvm_harness(module: &crate::mir::MirModule, tag: &str) -> Result<i32, String> {
+    let py3 = which::which("python3").map_err(|e| format!("python3 not found: {}", e))?;
+    let runner = std::path::Path::new("tools/pyvm_runner.py");
+    if !runner.exists() {
+        return Err(format!("PyVM runner not found: {}", runner.display()));
+    }
+    let tmp_dir = std::path::Path::new("tmp");
+    let _ = std::fs::create_dir_all(tmp_dir);
+    let mir_json_path = tmp_dir.join("nyash_pyvm_mir.json");
+    crate::runner::mir_json_emit::emit_mir_json_for_harness_bin(module, &mir_json_path)
+        .map_err(|e| format!("PyVM MIR JSON emit error: {}", e))?;
+    crate::cli_v!("[ny-compiler] using PyVM ({} ) → {}", tag, mir_json_path.display());
+    // Determine entry function hint (prefer Main.main if present)
+    let entry = if module.functions.contains_key("Main.main") {
+        "Main.main"
+    } else if module.functions.contains_key("main") {
+        "main"
+    } else {
+        "Main.main"
+    };
+    let status = std::process::Command::new(py3)
+        .args([
+            runner.to_string_lossy().as_ref(),
+            "--in",
+            &mir_json_path.display().to_string(),
+            "--entry",
+            entry,
+        ])
+        .status()
+        .map_err(|e| format!("spawn pyvm: {}", e))?;
+    let code = status.code().unwrap_or(1);
+    if !status.success() {
+        crate::cli_v!("❌ PyVM ({}) failed (status={})", tag, code);
+    }
+    Ok(code)
+}

src/runner/modes/common_util/selfhost_exe.rs

@@ -0,0 +1,131 @@
+use std::io::Read;
+use std::process::Stdio;
+use std::thread::sleep;
+use std::time::{Duration, Instant};
+
+/// Try external selfhost compiler EXE to parse Ny -> JSON v0 and return MIR module.
+/// Returns Some(module) on success, None on failure (timeout/invalid output/missing exe)
+pub fn exe_try_parse_json_v0(filename: &str, timeout_ms: u64) -> Option<crate::mir::MirModule> {
+    // Resolve parser EXE path
+    let exe_path = if let Ok(p) = std::env::var("NYASH_NY_COMPILER_EXE_PATH") {
+        std::path::PathBuf::from(p)
+    } else {
+        let mut p = std::path::PathBuf::from("dist/nyash_compiler");
+        #[cfg(windows)]
+        {
+            p.push("nyash_compiler.exe");
+        }
+        #[cfg(not(windows))]
+        {
+            p.push("nyash_compiler");
+        }
+        if !p.exists() {
+            if let Ok(w) = which::which("nyash_compiler") {
+                w
+            } else {
+                p
+            }
+        } else {
+            p
+        }
+    };
+    if !exe_path.exists() {
+        crate::cli_v!("[ny-compiler] exe not found at {}", exe_path.display());
+        return None;
+    }
+    // Build command
+    let mut cmd = std::process::Command::new(&exe_path);
+    cmd.arg(filename);
+    if crate::config::env::ny_compiler_min_json() {
+        cmd.arg("--min-json");
+    }
+    if crate::config::env::selfhost_read_tmp() {
+        cmd.arg("--read-tmp");
+    }
+    if let Some(raw) = crate::config::env::ny_compiler_child_args() {
+        for tok in raw.split_whitespace() {
+            cmd.arg(tok);
+        }
+    }
+    let mut cmd = cmd.stdout(Stdio::piped()).stderr(Stdio::piped());
+    let mut child = match cmd.spawn() {
+        Ok(c) => c,
+        Err(e) => {
+            eprintln!("[ny-compiler] exe spawn failed: {}", e);
+            return None;
+        }
+    };
+    let mut ch_stdout = child.stdout.take();
+    let mut ch_stderr = child.stderr.take();
+    let start = Instant::now();
+    let mut timed_out = false;
+    loop {
+        match child.try_wait() {
+            Ok(Some(_)) => break,
+            Ok(None) => {
+                if start.elapsed() >= Duration::from_millis(timeout_ms) {
+                    let _ = child.kill();
+                    let _ = child.wait();
+                    timed_out = true;
+                    break;
+                }
+                sleep(Duration::from_millis(10));
+            }
+            Err(e) => {
+                eprintln!("[ny-compiler] exe wait error: {}", e);
+                return None;
+            }
+        }
+    }
+    let mut out_buf = Vec::new();
+    let mut err_buf = Vec::new();
+    if let Some(mut s) = ch_stdout {
+        let _ = s.read_to_end(&mut out_buf);
+    }
+    if let Some(mut s) = ch_stderr {
+        let _ = s.read_to_end(&mut err_buf);
+    }
+    if timed_out {
+        let head = String::from_utf8_lossy(&out_buf)
+            .chars()
+            .take(200)
+            .collect::<String>();
+        eprintln!(
+            "[ny-compiler] exe timeout after {} ms; stdout(head)='{}'",
+            timeout_ms,
+            head.replace('\n', "\\n")
+        );
+        return None;
+    }
+    let stdout = match String::from_utf8(out_buf) {
+        Ok(s) => s,
+        Err(_) => String::new(),
+    };
+    let mut json_line = String::new();
+    for line in stdout.lines() {
+        let t = line.trim();
+        if t.starts_with('{') && t.contains("\"version\"") && t.contains("\"kind\"") {
+            json_line = t.to_string();
+            break;
+        }
+    }
+    if json_line.is_empty() {
+        if crate::config::env::cli_verbose() {
+            let head: String = stdout.chars().take(200).collect();
+            let errh: String = String::from_utf8_lossy(&err_buf).chars().take(200).collect();
+            crate::cli_v!(
+                "[ny-compiler] exe produced no JSON; stdout(head)='{}' stderr(head)='{}'",
+                head.replace('\n', "\\n"),
+                errh.replace('\n', "\\n")
+            );
+        }
+        return None;
+    }
+    match crate::runner::json_v0_bridge::parse_json_v0_to_module(&json_line) {
+        Ok(module) => Some(module),
+        Err(e) => {
+            eprintln!("[ny-compiler] JSON parse failed: {}", e);
+            None
+        }
+    }
+}

src/runner/modes/llvm.rs

@@ -84,21 +84,22 @@ impl NyashRunner {
                                 );
                             }
                             // 2) Run harness with --in/--out（失敗時は即エラー）
-                            let status = std::process::Command::new(py3)
-                                .args([
-                                    harness.to_string_lossy().as_ref(),
-                                    "--in",
-                                    &mir_json_path.display().to_string(),
-                                    "--out",
-                                    &_out_path,
-                                ])
-                                .status()
+                            let mut cmd = std::process::Command::new(py3);
+                            cmd.args([
+                                harness.to_string_lossy().as_ref(),
+                                "--in",
+                                &mir_json_path.display().to_string(),
+                                "--out",
+                                &_out_path,
+                            ]);
+                            let out = crate::runner::modes::common_util::io::spawn_with_timeout(cmd, 20_000)
                                 .map_err(|e| format!("spawn harness: {}", e))
                                 .unwrap();
-                            if !status.success() {
+                            if out.timed_out || !out.status_ok {
                                 eprintln!(
-                                    "❌ llvmlite harness failed (status={})",
-                                    status.code().unwrap_or(-1)
+                                    "❌ llvmlite harness failed (timeout={} code={:?})",
+                                    out.timed_out,
+                                    out.exit_code
                                 );
                                 process::exit(1);
                             }

src/runner/modes/mod.rs

@@ -8,5 +8,8 @@ pub mod mir;
 pub mod vm;
 pub mod pyvm;
 
+// Shared helpers extracted from common.rs (in progress)
+pub mod common_util;
+
 #[cfg(feature = "cranelift-jit")]
 pub mod aot;

src/runner/modes/pyvm.rs

@@ -76,22 +76,20 @@ pub fn execute_pyvm_only(_runner: &NyashRunner, filename: &str) {
                 mir_json_path.display()
             );
         }
-        let status = std::process::Command::new(py3)
-            .args([
-                runner.to_string_lossy().as_ref(),
-                "--in",
-                &mir_json_path.display().to_string(),
-                "--entry",
-                entry,
-            ])
-            .status()
+        let mut cmd = std::process::Command::new(py3);
+        cmd.args([
+            runner.to_string_lossy().as_ref(),
+            "--in",
+            &mir_json_path.display().to_string(),
+            "--entry",
+            entry,
+        ]);
+        let out = crate::runner::modes::common_util::io::spawn_with_timeout(cmd, 10_000)
             .map_err(|e| format!("spawn pyvm: {}", e))
             .unwrap();
-        let code = status.code().unwrap_or(1);
-        if !status.success() {
-            if std::env::var("NYASH_CLI_VERBOSE").ok().as_deref() == Some("1") {
-                eprintln!("❌ PyVM failed (status={})", code);
-            }
+        let code = if out.timed_out { 1 } else { out.exit_code.unwrap_or(1) };
+        if out.timed_out && std::env::var("NYASH_CLI_VERBOSE").ok().as_deref() == Some("1") {
+            eprintln!("❌ PyVM timeout");
         }
         process::exit(code);
     } else {
@@ -99,4 +97,3 @@ pub fn execute_pyvm_only(_runner: &NyashRunner, filename: &str) {
         process::exit(1);
     }
 }
-

src/runner/modes/vm.rs

@@ -207,23 +207,20 @@ impl NyashRunner {
                         "Main.main"
                     };
                     // Spawn runner
-                    let status = std::process::Command::new(py3)
-                        .args([
-                            runner.to_string_lossy().as_ref(),
-                            "--in",
-                            &mir_json_path.display().to_string(),
-                            "--entry",
-                            entry,
-                        ])
-                        .status()
+                    let mut cmd = std::process::Command::new(py3);
+                    cmd.args([
+                        runner.to_string_lossy().as_ref(),
+                        "--in",
+                        &mir_json_path.display().to_string(),
+                        "--entry",
+                        entry,
+                    ]);
+                    let out = super::common_util::io::spawn_with_timeout(cmd, 10_000)
                         .map_err(|e| format!("spawn pyvm: {}", e))
                         .unwrap();
-                    // Always propagate PyVM exit code to match llvmlite semantics
-                    let code = status.code().unwrap_or(1);
-                    if !status.success() {
-                        if std::env::var("NYASH_CLI_VERBOSE").ok().as_deref() == Some("1") {
-                            eprintln!("❌ PyVM failed (status={})", code);
-                        }
+                    let code = if out.timed_out { 1 } else { out.exit_code.unwrap_or(1) };
+                    if out.timed_out && std::env::var("NYASH_CLI_VERBOSE").ok().as_deref() == Some("1") {
+                        eprintln!("❌ PyVM timeout");
                     }
                     process::exit(code);
                 } else {

src/runner/selfhost.rs

@@ -248,14 +248,15 @@ impl NyashRunner {
                 if py.exists() {
                     let mut cmd = std::process::Command::new(&py3);
                     cmd.arg(py).arg(&tmp_path);
-                    let out = match cmd.output() {
+                    let timeout_ms: u64 = std::env::var("NYASH_NY_COMPILER_TIMEOUT_MS")
+                        .ok()
+                        .and_then(|s| s.parse().ok())
+                        .unwrap_or(2000);
+                    let out = match super::modes::common_util::io::spawn_with_timeout(cmd, timeout_ms) {
                         Ok(o) => o,
-                        Err(e) => {
-                            eprintln!("[ny-compiler] python harness failed to spawn: {}", e);
-                            return false;
-                        }
+                        Err(e) => { eprintln!("[ny-compiler] python harness failed: {}", e); return false; }
                     };
-                    if out.status.success() {
+                    if !out.timed_out {
                         if let Ok(line) = String::from_utf8(out.stdout)
                             .map(|s| s.lines().next().unwrap_or("").to_string())
                         {
@@ -366,179 +367,48 @@ impl NyashRunner {
                 }
             };
             if exe_path.exists() {
-                let mut cmd = std::process::Command::new(&exe_path);
-                // Prefer passing the original filename directly (parser EXE accepts positional path)
-                cmd.arg(filename);
-                // Gates
-                if std::env::var("NYASH_NY_COMPILER_MIN_JSON").ok().as_deref() == Some("1") {
-                    cmd.arg("--min-json");
-                }
-                if std::env::var("NYASH_SELFHOST_READ_TMP").ok().as_deref() == Some("1") {
-                    cmd.arg("--read-tmp");
-                }
-                if std::env::var("NYASH_NY_COMPILER_STAGE3").ok().as_deref() == Some("1") {
-                    cmd.arg("--stage3");
-                }
-                if let Ok(raw) = std::env::var("NYASH_NY_COMPILER_CHILD_ARGS") {
-                    for tok in raw.split_whitespace() {
-                        cmd.arg(tok);
-                    }
-                }
                 let timeout_ms: u64 = std::env::var("NYASH_NY_COMPILER_TIMEOUT_MS")
                     .ok()
                     .and_then(|s| s.parse().ok())
                     .unwrap_or(2000);
-                let mut cmd = cmd.stdout(Stdio::piped()).stderr(Stdio::piped());
-                let mut child = match cmd.spawn() {
-                    Ok(c) => c,
-                    Err(e) => {
-                        eprintln!("[ny-compiler] exe spawn failed: {}", e);
-                        return false;
-                    }
-                };
-                let mut ch_stdout = child.stdout.take();
-                let mut ch_stderr = child.stderr.take();
-                let start = Instant::now();
-                let mut timed_out = false;
-                loop {
-                    match child.try_wait() {
-                        Ok(Some(_status)) => {
-                            break;
-                        }
-                        Ok(None) => {
-                            if start.elapsed() >= Duration::from_millis(timeout_ms) {
-                                let _ = child.kill();
-                                let _ = child.wait();
-                                timed_out = true;
-                                break;
-                            }
-                            sleep(Duration::from_millis(10));
-                        }
-                        Err(e) => {
-                            eprintln!("[ny-compiler] exe wait error: {}", e);
-                            return false;
-                        }
-                    }
-                }
-                let mut out_buf = Vec::new();
-                let mut err_buf = Vec::new();
-                if let Some(mut s) = ch_stdout {
-                    let _ = s.read_to_end(&mut out_buf);
-                }
-                if let Some(mut s) = ch_stderr {
-                    let _ = s.read_to_end(&mut err_buf);
-                }
-                if timed_out {
-                    let head = String::from_utf8_lossy(&out_buf)
-                        .chars()
-                        .take(200)
-                        .collect::<String>();
-                    eprintln!(
-                        "[ny-compiler] exe timeout after {} ms; stdout(head)='{}'",
-                        timeout_ms,
-                        head.replace('\n', "\\n")
-                    );
-                    return false;
-                }
-                let stdout = match String::from_utf8(out_buf) {
-                    Ok(s) => s,
-                    Err(_) => String::new(),
-                };
-                let mut json_line = String::new();
-                for line in stdout.lines() {
-                    let t = line.trim();
-                    if t.starts_with('{') && t.contains("\"version\"") && t.contains("\"kind\"") {
-                        json_line = t.to_string();
-                        break;
-                    }
-                }
-                if json_line.is_empty() {
-                    if std::env::var("NYASH_CLI_VERBOSE").ok().as_deref() == Some("1") {
-                        let head: String = stdout.chars().take(200).collect();
-                        let errh: String = String::from_utf8_lossy(&err_buf)
-                            .chars()
-                            .take(200)
-                            .collect();
-                        eprintln!("[ny-compiler] exe produced no JSON; stdout(head)='{}' stderr(head)='{}'", head.replace('\n', "\\n"), errh.replace('\n', "\\n"));
-                    }
-                    return false;
-                }
-                // Parse JSON v0 → MIR module
-                match super::json_v0_bridge::parse_json_v0_to_module(&json_line) {
-                    Ok(module) => {
-                        println!("🚀 Ny compiler EXE path (ny→json_v0) ON");
-                        super::json_v0_bridge::maybe_dump_mir(&module);
-                        let emit_only = std::env::var("NYASH_NY_COMPILER_EMIT_ONLY")
-                            .unwrap_or_else(|_| "1".to_string())
-                            == "1";
-                        if emit_only {
-                            return false;
-                        } else {
-                            // Prefer PyVM when requested (reference semantics), regardless of BoxCall presence
-                            let prefer_pyvm =
-                                std::env::var("NYASH_VM_USE_PY").ok().as_deref() == Some("1");
-                            if prefer_pyvm {
-                                if let Ok(py3) = which::which("python3") {
-                                    let runner = std::path::Path::new("tools/pyvm_runner.py");
-                                    if runner.exists() {
-                                        let tmp_dir = std::path::Path::new("tmp");
-                                        let _ = std::fs::create_dir_all(tmp_dir);
-                                        let mir_json_path = tmp_dir.join("nyash_pyvm_mir.json");
-                                        if let Err(e) = crate::runner::mir_json_emit::emit_mir_json_for_harness_bin(&module, &mir_json_path) {
-                                            eprintln!("❌ PyVM MIR JSON emit error: {}", e);
-                                            process::exit(1);
-                                        }
-                                        if std::env::var("NYASH_CLI_VERBOSE").ok().as_deref()
-                                            == Some("1")
-                                        {
-                                            eprintln!(
-                                                "[Bridge] using PyVM (selfhost) → {}",
-                                                mir_json_path.display()
-                                            );
-                                        }
-                                        let entry = if module.functions.contains_key("Main.main") {
-                                            "Main.main"
-                                        } else if module.functions.contains_key("main") {
-                                            "main"
-                                        } else {
-                                            "Main.main"
-                                        };
-                                        let status = std::process::Command::new(py3)
-                                            .args([
-                                                "tools/pyvm_runner.py",
-                                                "--in",
-                                                &mir_json_path.display().to_string(),
-                                                "--entry",
-                                                entry,
-                                            ])
-                                            .status()
-                                            .map_err(|e| format!("spawn pyvm: {}", e))
-                                            .unwrap();
-                                        let code = status.code().unwrap_or(1);
-                                        if !status.success() {
-                                            if std::env::var("NYASH_CLI_VERBOSE").ok().as_deref()
-                                                == Some("1")
-                                            {
-                                                eprintln!(
-                                                    "❌ PyVM (selfhost) failed (status={})",
-                                                    code
-                                                );
-                                            }
-                                        }
-                                        // Harmonize with interpreter path for smokes: print Result then exit code
-                                        println!("Result: {}", code);
-                                        std::process::exit(code);
-                                    }
+                if let Some(module) = super::modes::common_util::selfhost_exe::exe_try_parse_json_v0(filename, timeout_ms) {
+                    super::json_v0_bridge::maybe_dump_mir(&module);
+                    let emit_only = std::env::var("NYASH_NY_COMPILER_EMIT_ONLY")
+                        .unwrap_or_else(|_| "1".to_string())
+                        == "1";
+                    if emit_only { return false; }
+                    // Prefer PyVM when requested (reference semantics)
+                    if std::env::var("NYASH_VM_USE_PY").ok().as_deref() == Some("1") {
+                        if let Ok(py3) = which::which("python3") {
+                            let runner = std::path::Path::new("tools/pyvm_runner.py");
+                            if runner.exists() {
+                                let tmp_dir = std::path::Path::new("tmp");
+                                let _ = std::fs::create_dir_all(tmp_dir);
+                                let mir_json_path = tmp_dir.join("nyash_pyvm_mir.json");
+                                if let Err(e) = crate::runner::mir_json_emit::emit_mir_json_for_harness_bin(&module, &mir_json_path) {
+                                    eprintln!("❌ PyVM MIR JSON emit error: {}", e);
+                                    process::exit(1);
                                 }
+                                if std::env::var("NYASH_CLI_VERBOSE").ok().as_deref() == Some("1") {
+                                    eprintln!("[Bridge] using PyVM (selfhost) → {}", mir_json_path.display());
+                                }
+                                let entry = if module.functions.contains_key("Main.main") { "Main.main" }
+                                            else if module.functions.contains_key("main") { "main" } else { "Main.main" };
+                                let status = std::process::Command::new(py3)
+                                    .args(["tools/pyvm_runner.py", "--in", &mir_json_path.display().to_string(), "--entry", entry])
+                                    .status()
+                                    .map_err(|e| format!("spawn pyvm: {}", e))
+                                    .unwrap();
+                                let code = status.code().unwrap_or(1);
+                                println!("Result: {}", code);
+                                std::process::exit(code);
                             }
-                            self.execute_mir_module(&module);
-                            return true;
                         }
                     }
-                    Err(e) => {
-                        eprintln!("[ny-compiler] json parse error: {}", e);
-                        return false;
-                    }
+                    self.execute_mir_module(&module);
+                    return true;
+                } else {
+                    return false;
                 }
             }
         }
@@ -578,52 +448,15 @@ impl NyashRunner {
                 .ok()
                 .and_then(|s| s.parse().ok())
                 .unwrap_or(2000);
-            let mut cmd = cmd.stdout(Stdio::piped()).stderr(Stdio::piped());
-            let mut child = match cmd.spawn() {
-                Ok(c) => c,
-                Err(e) => {
-                    eprintln!("[ny-compiler] spawn inline vm failed: {}", e);
-                    return false;
-                }
+            let out = match super::modes::common_util::io::spawn_with_timeout(cmd, timeout_ms) {
+                Ok(o) => o,
+                Err(e) => { eprintln!("[ny-compiler] spawn inline vm failed: {}", e); return false; }
             };
-            let mut ch_stdout = child.stdout.take();
-            let mut ch_stderr = child.stderr.take();
-            let start = Instant::now();
-            let mut timed_out = false;
-            loop {
-                match child.try_wait() {
-                    Ok(Some(_)) => break,
-                    Ok(None) => {
-                        if start.elapsed() >= Duration::from_millis(timeout_ms) {
-                            let _ = child.kill();
-                            let _ = child.wait();
-                            timed_out = true;
-                            break;
-                        }
-                        sleep(Duration::from_millis(10));
-                    }
-                    Err(e) => {
-                        eprintln!("[ny-compiler] inline wait error: {}", e);
-                        break;
-                    }
-                }
+            if out.timed_out {
+                let head = String::from_utf8_lossy(&out.stdout).chars().take(200).collect::<String>();
+                eprintln!("[ny-compiler] inline timeout after {} ms; stdout(head)='{}'", timeout_ms, head.replace('\n', "\\n"));
             }
-            let mut out_buf = Vec::new();
-            if let Some(mut s) = ch_stdout {
-                let _ = s.read_to_end(&mut out_buf);
-            }
-            if timed_out {
-                let head = String::from_utf8_lossy(&out_buf)
-                    .chars()
-                    .take(200)
-                    .collect::<String>();
-                eprintln!(
-                    "[ny-compiler] inline timeout after {} ms; stdout(head)='{}'",
-                    timeout_ms,
-                    head.replace('\n', "\\n")
-                );
-            }
-            raw = String::from_utf8_lossy(&out_buf).to_string();
+            raw = String::from_utf8_lossy(&out.stdout).to_string();
         }
         let mut json_line = String::new();
         for line in raw.lines() {

src/runtime/gc.rs

@@ -11,11 +11,13 @@ pub enum BarrierKind {
 
 /// GC hooks that execution engines may call at key points.
 /// Implementations must be Send + Sync for multi-thread preparation.
-pub trait GcHooks: Send + Sync {
+pub trait GcHooks: Send + Sync + std::any::Any {
     /// Safe point for cooperative GC (e.g., poll or yield).
     fn safepoint(&self) {}
     /// Memory barrier hint for loads/stores.
     fn barrier(&self, _kind: BarrierKind) {}
+    /// Allocation accounting (bytes are best-effort; may be 0 when unknown)
+    fn alloc(&self, _bytes: u64) {}
     /// Optional counters snapshot for diagnostics. Default: None.
     fn snapshot_counters(&self) -> Option<(u64, u64, u64)> {
         None
@@ -27,48 +29,35 @@ pub struct NullGc;
 
 impl GcHooks for NullGc {}
 
-use std::sync::atomic::{AtomicU64, Ordering};
-
-/// Simple counting GC (PoC): counts safepoints and barriers.
-/// Useful to validate hook frequency without affecting semantics.
+/// CountingGc is now a thin wrapper around the unified GcController.
 pub struct CountingGc {
-    pub safepoints: AtomicU64,
-    pub barrier_reads: AtomicU64,
-    pub barrier_writes: AtomicU64,
+    inner: crate::runtime::gc_controller::GcController,
 }
 
 impl CountingGc {
     pub fn new() -> Self {
+        // Default to rc+cycle mode for development metrics
+        let mode = crate::runtime::gc_mode::GcMode::RcCycle;
         Self {
-            safepoints: AtomicU64::new(0),
-            barrier_reads: AtomicU64::new(0),
-            barrier_writes: AtomicU64::new(0),
+            inner: crate::runtime::gc_controller::GcController::new(mode),
         }
     }
     pub fn snapshot(&self) -> (u64, u64, u64) {
-        (
-            self.safepoints.load(Ordering::Relaxed),
-            self.barrier_reads.load(Ordering::Relaxed),
-            self.barrier_writes.load(Ordering::Relaxed),
-        )
+        self.inner.snapshot()
     }
 }
 
 impl GcHooks for CountingGc {
     fn safepoint(&self) {
-        self.safepoints.fetch_add(1, Ordering::Relaxed);
+        self.inner.safepoint();
     }
     fn barrier(&self, kind: BarrierKind) {
-        match kind {
-            BarrierKind::Read => {
-                self.barrier_reads.fetch_add(1, Ordering::Relaxed);
-            }
-            BarrierKind::Write => {
-                self.barrier_writes.fetch_add(1, Ordering::Relaxed);
-            }
-        }
+        self.inner.barrier(kind);
+    }
+    fn alloc(&self, bytes: u64) {
+        self.inner.alloc(bytes);
     }
     fn snapshot_counters(&self) -> Option<(u64, u64, u64)> {
-        Some(self.snapshot())
+        Some(self.inner.snapshot())
     }
 }

src/runtime/gc_controller.rs

@@ -0,0 +1,207 @@
+//! Unified GC controller (skeleton)
+//! Implements GcHooks and centralizes mode selection and metrics.
+
+use std::sync::atomic::{AtomicU64, Ordering};
+
+use super::gc::{BarrierKind, GcHooks};
+use super::gc_mode::GcMode;
+use crate::config::env;
+use crate::runtime::gc_trace;
+use std::collections::{HashSet, VecDeque};
+
+pub struct GcController {
+    mode: GcMode,
+    safepoints: AtomicU64,
+    barrier_reads: AtomicU64,
+    barrier_writes: AtomicU64,
+    alloc_bytes: AtomicU64,
+    alloc_count: AtomicU64,
+    sp_since_last: AtomicU64,
+    bytes_since_last: AtomicU64,
+    collect_sp_interval: Option<u64>,
+    collect_alloc_bytes: Option<u64>,
+    // Diagnostics: last trial reachability counters
+    trial_nodes_last: AtomicU64,
+    trial_edges_last: AtomicU64,
+    // Diagnostics: collection counters and last duration/flags
+    collect_count_total: AtomicU64,
+    collect_by_sp: AtomicU64,
+    collect_by_alloc: AtomicU64,
+    trial_duration_last_ms: AtomicU64,
+    trial_reason_last: AtomicU64, // bitflags: 1=sp, 2=alloc
+}
+
+impl GcController {
+    pub fn new(mode: GcMode) -> Self {
+        Self {
+            mode,
+            safepoints: AtomicU64::new(0),
+            barrier_reads: AtomicU64::new(0),
+            barrier_writes: AtomicU64::new(0),
+            alloc_bytes: AtomicU64::new(0),
+            alloc_count: AtomicU64::new(0),
+            sp_since_last: AtomicU64::new(0),
+            bytes_since_last: AtomicU64::new(0),
+            collect_sp_interval: env::gc_collect_sp_interval(),
+            collect_alloc_bytes: env::gc_collect_alloc_bytes(),
+            trial_nodes_last: AtomicU64::new(0),
+            trial_edges_last: AtomicU64::new(0),
+            collect_count_total: AtomicU64::new(0),
+            collect_by_sp: AtomicU64::new(0),
+            collect_by_alloc: AtomicU64::new(0),
+            trial_duration_last_ms: AtomicU64::new(0),
+            trial_reason_last: AtomicU64::new(0),
+        }
+    }
+    pub fn mode(&self) -> GcMode {
+        self.mode
+    }
+    pub fn snapshot(&self) -> (u64, u64, u64) {
+        (
+            self.safepoints.load(Ordering::Relaxed),
+            self.barrier_reads.load(Ordering::Relaxed),
+            self.barrier_writes.load(Ordering::Relaxed),
+        )
+    }
+}
+
+impl GcHooks for GcController {
+    fn safepoint(&self) {
+        // Off mode: minimal overhead but still callable
+        if self.mode != GcMode::Off {
+            self.safepoints.fetch_add(1, Ordering::Relaxed);
+            let sp = self.sp_since_last.fetch_add(1, Ordering::Relaxed) + 1;
+            // Opportunistic collection trigger
+            let sp_hit = self
+                .collect_sp_interval
+                .map(|n| n > 0 && sp >= n)
+                .unwrap_or(false);
+            let bytes = self.bytes_since_last.load(Ordering::Relaxed);
+            let bytes_hit = self
+                .collect_alloc_bytes
+                .map(|n| n > 0 && bytes >= n)
+                .unwrap_or(false);
+            if sp_hit || bytes_hit {
+                // Record reason flags for diagnostics
+                let mut flags: u64 = 0;
+                if sp_hit { flags |= 1; self.collect_by_sp.fetch_add(1, Ordering::Relaxed); }
+                if bytes_hit { flags |= 2; self.collect_by_alloc.fetch_add(1, Ordering::Relaxed); }
+                self.trial_reason_last.store(flags, Ordering::Relaxed);
+                self.run_trial_collection();
+            }
+        }
+        // Future: per-mode collection/cooperation hooks
+    }
+    fn barrier(&self, kind: BarrierKind) {
+        if self.mode == GcMode::Off {
+            return;
+        }
+        match kind {
+            BarrierKind::Read => {
+                self.barrier_reads.fetch_add(1, Ordering::Relaxed);
+            }
+            BarrierKind::Write => {
+                self.barrier_writes.fetch_add(1, Ordering::Relaxed);
+            }
+        }
+    }
+    fn snapshot_counters(&self) -> Option<(u64, u64, u64)> {
+        Some(self.snapshot())
+    }
+    fn alloc(&self, bytes: u64) {
+        if self.mode == GcMode::Off {
+            return;
+        }
+        self.alloc_count.fetch_add(1, Ordering::Relaxed);
+        self.alloc_bytes.fetch_add(bytes, Ordering::Relaxed);
+        self.bytes_since_last
+            .fetch_add(bytes, Ordering::Relaxed);
+    }
+}
+
+impl GcController {
+    pub fn alloc_totals(&self) -> (u64, u64) {
+        (
+            self.alloc_count.load(Ordering::Relaxed),
+            self.alloc_bytes.load(Ordering::Relaxed),
+        )
+    }
+}
+
+impl GcController {
+    fn run_trial_collection(&self) {
+        // Reset windows
+        self.sp_since_last.store(0, Ordering::Relaxed);
+        self.bytes_since_last.store(0, Ordering::Relaxed);
+        // PoC: no object graph; report current handles as leak candidates and return.
+        if self.mode == GcMode::Off {
+            return;
+        }
+        // Only run for rc/rc+cycle/stw; rc+cycle is default.
+        match self.mode {
+            GcMode::Rc | GcMode::RcCycle | GcMode::STW => {
+                let started = std::time::Instant::now();
+                // Roots: JIT/AOT handle registry snapshot
+                let roots = crate::jit::rt::handles::snapshot_arcs();
+                let mut visited: HashSet<u64> = HashSet::new();
+                let mut q: VecDeque<std::sync::Arc<dyn crate::box_trait::NyashBox>> =
+                    VecDeque::new();
+                for r in roots.into_iter() {
+                    let id = r.box_id();
+                    if visited.insert(id) {
+                        q.push_back(r);
+                    }
+                }
+                let mut nodes: u64 = visited.len() as u64;
+                let mut edges: u64 = 0;
+                while let Some(cur) = q.pop_front() {
+                    gc_trace::trace_children(&*cur, &mut |child| {
+                        edges += 1;
+                        let id = child.box_id();
+                        if visited.insert(id) {
+                            nodes += 1;
+                            q.push_back(child);
+                        }
+                    });
+                }
+                // Store last diagnostics (available for JSON metrics)
+                self.trial_nodes_last.store(nodes, Ordering::Relaxed);
+                self.trial_edges_last.store(edges, Ordering::Relaxed);
+                if (nodes + edges) > 0 && crate::config::env::gc_metrics() {
+                    eprintln!(
+                        "[GC] trial: reachable nodes={} edges={} (roots=jit_handles)",
+                        nodes, edges
+                    );
+                }
+                // Update counters
+                let dur = started.elapsed();
+                let ms = dur.as_millis() as u64;
+                self.trial_duration_last_ms.store(ms, Ordering::Relaxed);
+                self.collect_count_total.fetch_add(1, Ordering::Relaxed);
+                // Reason flags derive from current env thresholds vs last windows reaching triggers
+                // Note: we set flags in safepoint() where triggers were decided.
+            }
+            _ => {}
+        }
+    }
+}
+
+impl GcController {
+    pub fn trial_reachability_last(&self) -> (u64, u64) {
+        (
+            self.trial_nodes_last.load(Ordering::Relaxed),
+            self.trial_edges_last.load(Ordering::Relaxed),
+        )
+    }
+    pub fn collection_totals(&self) -> (u64, u64, u64) {
+        (
+            self.collect_count_total.load(Ordering::Relaxed),
+            self.collect_by_sp.load(Ordering::Relaxed),
+            self.collect_by_alloc.load(Ordering::Relaxed),
+        )
+    }
+    pub fn trial_duration_last_ms(&self) -> u64 {
+        self.trial_duration_last_ms.load(Ordering::Relaxed)
+    }
+    pub fn trial_reason_last_bits(&self) -> u64 { self.trial_reason_last.load(Ordering::Relaxed) }
+}

src/runtime/gc_mode.rs

@@ -0,0 +1,34 @@
+//! GC mode selection (user-facing)
+use crate::config::env;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum GcMode {
+    RcCycle,
+    Minorgen,
+    STW,
+    Rc,
+    Off,
+}
+
+impl GcMode {
+    pub fn from_env() -> Self {
+        match env::gc_mode().to_ascii_lowercase().as_str() {
+            "auto" | "rc+cycle" => GcMode::RcCycle,
+            "minorgen" => GcMode::Minorgen,
+            "stw" => GcMode::STW,
+            "rc" => GcMode::Rc,
+            "off" => GcMode::Off,
+            _ => GcMode::RcCycle,
+        }
+    }
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            GcMode::RcCycle => "rc+cycle",
+            GcMode::Minorgen => "minorgen",
+            GcMode::STW => "stw",
+            GcMode::Rc => "rc",
+            GcMode::Off => "off",
+        }
+    }
+}
+

src/runtime/gc_trace.rs

@@ -0,0 +1,35 @@
+//! Minimal GC tracing helpers (skeleton)
+//!
+//! Downcast-based child edge enumeration for builtin containers.
+//! This is a non-invasive helper to support diagnostics and future collectors.
+
+use std::sync::Arc;
+
+use crate::box_trait::NyashBox;
+
+/// Visit child boxes of a given object and invoke `visit(child)` for each.
+/// This function recognizes builtin containers (ArrayBox/MapBox) and is a no-op otherwise.
+pub fn trace_children(obj: &dyn NyashBox, visit: &mut dyn FnMut(Arc<dyn NyashBox>)) {
+    // ArrayBox
+    if let Some(arr) = obj.as_any().downcast_ref::<crate::boxes::array::ArrayBox>() {
+        if let Ok(items) = arr.items.read() {
+            for it in items.iter() {
+                // Convert Box<dyn NyashBox> to Arc<dyn NyashBox>
+                let arc: Arc<dyn NyashBox> = Arc::from(it.clone_box());
+                visit(arc);
+            }
+        }
+        return;
+    }
+    // MapBox
+    if let Some(map) = obj.as_any().downcast_ref::<crate::boxes::map_box::MapBox>() {
+        if let Ok(data) = map.get_data().read() {
+            for (_k, v) in data.iter() {
+                let arc: Arc<dyn NyashBox> = Arc::from(v.clone_box());
+                visit(arc);
+            }
+        }
+        return;
+    }
+}
+

src/runtime/global_hooks.rs

@@ -4,97 +4,74 @@ use once_cell::sync::OnceCell;
 use std::sync::{Arc, RwLock};
 
 use super::scheduler::CancellationToken;
-use super::{gc::GcHooks, scheduler::Scheduler};
+use super::{gc::BarrierKind, gc::GcHooks, scheduler::Scheduler};
 
-static GLOBAL_GC: OnceCell<RwLock<Option<Arc<dyn GcHooks>>>> = OnceCell::new();
-static GLOBAL_SCHED: OnceCell<RwLock<Option<Arc<dyn Scheduler>>>> = OnceCell::new();
-// Phase 2 scaffold: current task group's cancellation token (no-op default)
-static GLOBAL_CUR_TOKEN: OnceCell<RwLock<Option<CancellationToken>>> = OnceCell::new();
-// Phase 2 scaffold: current group's child futures registry (best-effort)
-static GLOBAL_GROUP_FUTURES: OnceCell<RwLock<Vec<crate::boxes::future::FutureWeak>>> =
-    OnceCell::new();
-// Strong ownership list for implicit group (pre-TaskGroup actualization)
-static GLOBAL_GROUP_STRONG: OnceCell<RwLock<Vec<crate::boxes::future::FutureBox>>> =
-    OnceCell::new();
-// Simple scope depth counter for implicit group (join-at-scope-exit footing)
-static TASK_SCOPE_DEPTH: OnceCell<RwLock<usize>> = OnceCell::new();
-// TaskGroup scope stack (explicit group ownership per function scope)
-static TASK_GROUP_STACK: OnceCell<
-    RwLock<Vec<std::sync::Arc<crate::boxes::task_group_box::TaskGroupInner>>>,
-> = OnceCell::new();
+// Unified global runtime hooks state (single lock for consistency)
+struct GlobalHooksState {
+    gc: Option<Arc<dyn GcHooks>>,
+    sched: Option<Arc<dyn Scheduler>>,
+    cur_token: Option<CancellationToken>,
+    futures: Vec<crate::boxes::future::FutureWeak>,
+    strong: Vec<crate::boxes::future::FutureBox>,
+    scope_depth: usize,
+    group_stack: Vec<std::sync::Arc<crate::boxes::task_group_box::TaskGroupInner>>,
+}
 
-fn gc_cell() -> &'static RwLock<Option<Arc<dyn GcHooks>>> {
-    GLOBAL_GC.get_or_init(|| RwLock::new(None))
+impl GlobalHooksState {
+    fn new() -> Self {
+        Self {
+            gc: None,
+            sched: None,
+            cur_token: None,
+            futures: Vec::new(),
+            strong: Vec::new(),
+            scope_depth: 0,
+            group_stack: Vec::new(),
+        }
+    }
 }
-fn sched_cell() -> &'static RwLock<Option<Arc<dyn Scheduler>>> {
-    GLOBAL_SCHED.get_or_init(|| RwLock::new(None))
-}
-fn token_cell() -> &'static RwLock<Option<CancellationToken>> {
-    GLOBAL_CUR_TOKEN.get_or_init(|| RwLock::new(None))
-}
-fn futures_cell() -> &'static RwLock<Vec<crate::boxes::future::FutureWeak>> {
-    GLOBAL_GROUP_FUTURES.get_or_init(|| RwLock::new(Vec::new()))
-}
-fn strong_cell() -> &'static RwLock<Vec<crate::boxes::future::FutureBox>> {
-    GLOBAL_GROUP_STRONG.get_or_init(|| RwLock::new(Vec::new()))
-}
-fn scope_depth_cell() -> &'static RwLock<usize> {
-    TASK_SCOPE_DEPTH.get_or_init(|| RwLock::new(0))
-}
-fn group_stack_cell(
-) -> &'static RwLock<Vec<std::sync::Arc<crate::boxes::task_group_box::TaskGroupInner>>> {
-    TASK_GROUP_STACK.get_or_init(|| RwLock::new(Vec::new()))
+
+static GLOBAL_STATE: OnceCell<RwLock<GlobalHooksState>> = OnceCell::new();
+
+fn state() -> &'static RwLock<GlobalHooksState> {
+    GLOBAL_STATE.get_or_init(|| RwLock::new(GlobalHooksState::new()))
 }
 
 pub fn set_from_runtime(rt: &crate::runtime::nyash_runtime::NyashRuntime) {
-    if let Ok(mut g) = gc_cell().write() {
-        *g = Some(rt.gc.clone());
-    }
-    if let Ok(mut s) = sched_cell().write() {
-        *s = rt.scheduler.as_ref().cloned();
-    }
-    // Optional: initialize a fresh token for the runtime's root group (Phase 2 wiring)
-    if let Ok(mut t) = token_cell().write() {
-        if t.is_none() {
-            *t = Some(CancellationToken::new());
+    if let Ok(mut st) = state().write() {
+        st.gc = Some(rt.gc.clone());
+        st.sched = rt.scheduler.as_ref().cloned();
+        if st.cur_token.is_none() {
+            st.cur_token = Some(CancellationToken::new());
         }
-    }
-    // Reset group futures registry on new runtime
-    if let Ok(mut f) = futures_cell().write() {
-        f.clear();
-    }
-    if let Ok(mut s) = strong_cell().write() {
-        s.clear();
-    }
-    if let Ok(mut d) = scope_depth_cell().write() {
-        *d = 0;
-    }
-    if let Ok(mut st) = group_stack_cell().write() {
-        st.clear();
+        st.futures.clear();
+        st.strong.clear();
+        st.scope_depth = 0;
+        st.group_stack.clear();
     }
 }
 
 pub fn set_gc(gc: Arc<dyn GcHooks>) {
-    if let Ok(mut g) = gc_cell().write() {
-        *g = Some(gc);
+    if let Ok(mut st) = state().write() {
+        st.gc = Some(gc);
     }
 }
 pub fn set_scheduler(s: Arc<dyn Scheduler>) {
-    if let Ok(mut w) = sched_cell().write() {
-        *w = Some(s);
+    if let Ok(mut st) = state().write() {
+        st.sched = Some(s);
     }
 }
 /// Set the current task group's cancellation token (scaffold).
 pub fn set_current_group_token(tok: CancellationToken) {
-    if let Ok(mut w) = token_cell().write() {
-        *w = Some(tok);
+    if let Ok(mut st) = state().write() {
+        st.cur_token = Some(tok);
     }
 }
 
 /// Get the current task group's cancellation token (no-op default).
 pub fn current_group_token() -> CancellationToken {
-    if let Ok(r) = token_cell().read() {
-        if let Some(t) = r.as_ref() {
+    if let Ok(st) = state().read() {
+        if let Some(t) = st.cur_token.as_ref() {
             return t.clone();
         }
     }
@@ -103,21 +80,17 @@ pub fn current_group_token() -> CancellationToken {
 
 /// Register a Future into the current group's registry (best-effort; clones share state)
 pub fn register_future_to_current_group(fut: &crate::boxes::future::FutureBox) {
-    // Prefer explicit current TaskGroup at top of stack
-    if let Ok(st) = group_stack_cell().read() {
-        if let Some(inner) = st.last() {
+    if let Ok(mut st) = state().write() {
+        // Prefer explicit current TaskGroup at top of stack
+        if let Some(inner) = st.group_stack.last() {
             if let Ok(mut v) = inner.strong.lock() {
                 v.push(fut.clone());
                 return;
             }
         }
-    }
-    // Fallback to implicit global group
-    if let Ok(mut list) = futures_cell().write() {
-        list.push(fut.downgrade());
-    }
-    if let Ok(mut s) = strong_cell().write() {
-        s.push(fut.clone());
+        // Fallback to implicit global group
+        st.futures.push(fut.downgrade());
+        st.strong.push(fut.clone());
     }
 }
 
@@ -127,26 +100,15 @@ pub fn join_all_registered_futures(timeout_ms: u64) {
     let deadline = Instant::now() + Duration::from_millis(timeout_ms);
     loop {
         let mut all_ready = true;
-        // purge list of dropped or completed futures opportunistically
-        {
-            // purge weak list: keep only upgradeable futures
-            if let Ok(mut list) = futures_cell().write() {
-                list.retain(|fw| fw.is_ready().is_some());
-            }
-            // purge strong list: remove completed futures to reduce retention
-            if let Ok(mut s) = strong_cell().write() {
-                s.retain(|f| !f.ready());
-            }
-        }
-        // check readiness
-        {
-            if let Ok(list) = futures_cell().read() {
-                for fw in list.iter() {
-                    if let Some(ready) = fw.is_ready() {
-                        if !ready {
-                            all_ready = false;
-                            break;
-                        }
+        // purge + readiness check under single state lock (short critical sections)
+        if let Ok(mut st) = state().write() {
+            st.futures.retain(|fw| fw.is_ready().is_some());
+            st.strong.retain(|f| !f.ready());
+            for fw in st.futures.iter() {
+                if let Some(ready) = fw.is_ready() {
+                    if !ready {
+                        all_ready = false;
+                        break;
                     }
                 }
             }
@@ -161,22 +123,18 @@ pub fn join_all_registered_futures(timeout_ms: u64) {
         std::thread::yield_now();
     }
     // Final sweep
-    if let Ok(mut s) = strong_cell().write() {
-        s.retain(|f| !f.ready());
-    }
-    if let Ok(mut list) = futures_cell().write() {
-        list.retain(|fw| matches!(fw.is_ready(), Some(false)));
+    if let Ok(mut st) = state().write() {
+        st.strong.retain(|f| !f.ready());
+        st.futures.retain(|fw| matches!(fw.is_ready(), Some(false)));
     }
 }
 
 /// Push a task scope (footing). On pop of the outermost scope, perform a best-effort join.
 pub fn push_task_scope() {
-    if let Ok(mut d) = scope_depth_cell().write() {
-        *d += 1;
-    }
-    // Push a new explicit TaskGroup for this scope
-    if let Ok(mut st) = group_stack_cell().write() {
-        st.push(std::sync::Arc::new(
+    if let Ok(mut st) = state().write() {
+        st.scope_depth += 1;
+        // Push a new explicit TaskGroup for this scope
+        st.group_stack.push(std::sync::Arc::new(
             crate::boxes::task_group_box::TaskGroupInner {
                 strong: std::sync::Mutex::new(Vec::new()),
             },
@@ -190,19 +148,13 @@ pub fn push_task_scope() {
 pub fn pop_task_scope() {
     let mut do_join = false;
     let mut popped: Option<std::sync::Arc<crate::boxes::task_group_box::TaskGroupInner>> = None;
-    {
-        if let Ok(mut d) = scope_depth_cell().write() {
-            if *d > 0 {
-                *d -= 1;
-            }
-            if *d == 0 {
-                do_join = true;
-            }
+    if let Ok(mut st) = state().write() {
+        if st.scope_depth > 0 {
+            st.scope_depth -= 1;
         }
-    }
-    // Pop explicit group for this scope
-    if let Ok(mut st) = group_stack_cell().write() {
-        popped = st.pop();
+        if st.scope_depth == 0 { do_join = true; }
+        // Pop explicit group for this scope
+        popped = st.group_stack.pop();
     }
     if do_join {
         let ms: u64 = std::env::var("NYASH_TASK_SCOPE_JOIN_MS")
@@ -240,13 +192,11 @@ pub fn pop_task_scope() {
 
 /// Perform a runtime safepoint and poll the scheduler if available.
 pub fn safepoint_and_poll() {
-    if let Ok(g) = gc_cell().read() {
-        if let Some(gc) = g.as_ref() {
+    if let Ok(st) = state().read() {
+        if let Some(gc) = st.gc.as_ref() {
             gc.safepoint();
         }
-    }
-    if let Ok(s) = sched_cell().read() {
-        if let Some(sched) = s.as_ref() {
+        if let Some(sched) = st.sched.as_ref() {
             sched.poll();
         }
     }
@@ -255,8 +205,8 @@ pub fn safepoint_and_poll() {
 /// Try to schedule a task on the global scheduler. Returns true if scheduled.
 pub fn spawn_task(name: &str, f: Box<dyn FnOnce() + Send + 'static>) -> bool {
     // If a scheduler is registered, enqueue the task; otherwise run inline.
-    if let Ok(s) = sched_cell().read() {
-        if let Some(sched) = s.as_ref() {
+    if let Ok(st) = state().read() {
+        if let Some(sched) = st.sched.as_ref() {
             sched.spawn(name, f);
             return true;
         }
@@ -272,8 +222,8 @@ pub fn spawn_task_with_token(
     token: crate::runtime::scheduler::CancellationToken,
     f: Box<dyn FnOnce() + Send + 'static>,
 ) -> bool {
-    if let Ok(s) = sched_cell().read() {
-        if let Some(sched) = s.as_ref() {
+    if let Ok(st) = state().read() {
+        if let Some(sched) = st.sched.as_ref() {
             sched.spawn_with_token(name, token, f);
             return true;
         }
@@ -284,8 +234,8 @@ pub fn spawn_task_with_token(
 
 /// Spawn a delayed task via scheduler if available; returns true if scheduled.
 pub fn spawn_task_after(delay_ms: u64, name: &str, f: Box<dyn FnOnce() + Send + 'static>) -> bool {
-    if let Ok(s) = sched_cell().read() {
-        if let Some(sched) = s.as_ref() {
+    if let Ok(st) = state().read() {
+        if let Some(sched) = st.sched.as_ref() {
             sched.spawn_after(delay_ms, name, f);
             return true;
         }
@@ -297,3 +247,21 @@ pub fn spawn_task_after(delay_ms: u64, name: &str, f: Box<dyn FnOnce() + Send +
     });
     false
 }
+
+/// Forward a GC barrier event to the currently registered GC hooks (if any).
+pub fn gc_barrier(kind: BarrierKind) {
+    if let Ok(st) = state().read() {
+        if let Some(gc) = st.gc.as_ref() {
+            gc.barrier(kind);
+        }
+    }
+}
+
+/// Report an allocation to the current GC hooks (best-effort)
+pub fn gc_alloc(bytes: u64) {
+    if let Ok(st) = state().read() {
+        if let Some(gc) = st.gc.as_ref() {
+            gc.alloc(bytes);
+        }
+    }
+}

src/runtime/mod.rs

@@ -4,6 +4,9 @@
 
 pub mod box_registry;
 pub mod gc;
+pub mod gc_controller;
+pub mod gc_mode;
+pub mod gc_trace;
 pub mod global_hooks;
 pub mod leak_tracker;
 pub mod nyash_runtime;

src/runtime/plugin_loader_v2/enabled/loader.rs

@@ -1,4 +1,4 @@
-use super::types::{LoadedPluginV2, PluginBoxMetadata, PluginBoxV2, PluginHandleInner};
+use super::types::{LoadedPluginV2, NyashTypeBoxFfi, PluginBoxMetadata, PluginBoxV2, PluginHandleInner};
 use crate::bid::{BidError, BidResult};
 use crate::box_trait::NyashBox;
 use crate::config::nyash_toml_v2::{LibraryDefinition, NyashConfigV2};
@@ -12,11 +12,15 @@ fn dbg_on() -> bool {
     std::env::var("NYASH_DEBUG_PLUGIN").unwrap_or_default() == "1"
 }
 
+type BoxInvokeFn = extern "C" fn(u32, u32, *const u8, usize, *mut u8, *mut usize) -> i32;
+
 #[derive(Debug, Clone, Default)]
 struct LoadedBoxSpec {
     type_id: Option<u32>,
     methods: HashMap<String, MethodSpec>,
     fini_method_id: Option<u32>,
+    // Optional Nyash ABI v2 per-box invoke entry (not yet used for calls)
+    invoke_id: Option<BoxInvokeFn>,
 }
 #[derive(Debug, Clone, Copy)]
 struct MethodSpec {
@@ -124,7 +128,7 @@ impl PluginLoaderV2 {
         let lib = unsafe { Library::new(&lib_path) }.map_err(|_| BidError::PluginError)?;
         let lib_arc = Arc::new(lib);
 
-        // Resolve required invoke symbol (TypeBox v2: nyash_plugin_invoke)
+        // Resolve required invoke symbol (legacy library-level): nyash_plugin_invoke
         unsafe {
             let invoke_sym: Symbol<
                 unsafe extern "C" fn(u32, u32, u32, *const u8, usize, *mut u8, *mut usize) -> i32,
@@ -152,6 +156,35 @@ impl PluginLoaderV2 {
                 .insert(lib_name.to_string(), Arc::new(loaded));
         }
 
+        // Try to resolve Nyash ABI v2 per-box TypeBox symbols and record invoke_id
+        // Symbol pattern: nyash_typebox_<BoxType>
+        for box_type in &lib_def.boxes {
+            let sym_name = format!("nyash_typebox_{}\0", box_type);
+            unsafe {
+                if let Ok(tb_sym) = lib_arc.get::<Symbol<&NyashTypeBoxFfi>>(sym_name.as_bytes()) {
+                    let st: &NyashTypeBoxFfi = &*tb_sym;
+                    // Validate ABI tag 'TYBX' (0x54594258) and basic invariants
+                    let abi_ok = st.abi_tag == 0x5459_4258
+                        && st.struct_size as usize >= std::mem::size_of::<NyashTypeBoxFfi>();
+                    if !abi_ok {
+                        continue;
+                    }
+                    // Remember invoke_id in box_specs for (lib_name, box_type)
+                    if let Some(invoke_id) = st.invoke_id {
+                        let key = (lib_name.to_string(), box_type.to_string());
+                        let mut map = self.box_specs.write().map_err(|_| BidError::PluginError)?;
+                        let entry = map.entry(key).or_insert(LoadedBoxSpec {
+                            type_id: None,
+                            methods: HashMap::new(),
+                            fini_method_id: None,
+                            invoke_id: None,
+                        });
+                        entry.invoke_id = Some(invoke_id);
+                    }
+                }
+            }
+        }
+
         Ok(())
     }
 

tools/bootstrap_selfhost_smoke.sh

@@ -13,13 +13,16 @@ fi
 echo "[bootstrap] c0 (rust) → c1 (ny) → c1' parity (JIT-only)" >&2
 
 # c0: baseline run (rust path)
-NYASH_DISABLE_PLUGINS=1 NYASH_CLI_VERBOSE=1 "$BIN" --backend vm "$ROOT_DIR/apps/examples/string_p0.nyash" > /tmp/nyash-c0.out
+timeout -s KILL 20s env NYASH_DISABLE_PLUGINS=1 NYASH_CLI_VERBOSE=1 \
+  "$BIN" --backend vm "$ROOT_DIR/apps/examples/string_p0.nyash" > /tmp/nyash-c0.out
 
 # c1: try Ny compiler path (flagged); tolerate fallback to rust path
-NYASH_DISABLE_PLUGINS=1 NYASH_USE_NY_COMPILER=1 NYASH_CLI_VERBOSE=1 "$BIN" --backend vm "$ROOT_DIR/apps/examples/string_p0.nyash" > /tmp/nyash-c1.out || true
+timeout -s KILL 20s env NYASH_DISABLE_PLUGINS=1 NYASH_USE_NY_COMPILER=1 NYASH_CLI_VERBOSE=1 \
+  "$BIN" --backend vm "$ROOT_DIR/apps/examples/string_p0.nyash" > /tmp/nyash-c1.out || true
 
 # c1': re-run (simulated second pass)
-NYASH_DISABLE_PLUGINS=1 NYASH_USE_NY_COMPILER=1 NYASH_CLI_VERBOSE=1 "$BIN" --backend vm "$ROOT_DIR/apps/examples/string_p0.nyash" > /tmp/nyash-c1p.out || true
+timeout -s KILL 20s env NYASH_DISABLE_PLUGINS=1 NYASH_USE_NY_COMPILER=1 NYASH_CLI_VERBOSE=1 \
+  "$BIN" --backend vm "$ROOT_DIR/apps/examples/string_p0.nyash" > /tmp/nyash-c1p.out || true
 
 H0=$(rg -n '^Result:\s*' /tmp/nyash-c0.out | sed 's/\s\+/ /g')
 H1=$(rg -n '^Result:\s*' /tmp/nyash-c1.out | sed 's/\s\+/ /g' || true)

tools/exe_first_smoke.sh

@@ -15,7 +15,10 @@ mkdir -p dist/nyash_compiler/tmp
 echo 'return 1+2*3' > dist/nyash_compiler/tmp/sample_exe_smoke.nyash
 
 echo "[3/4] Running parser EXE → JSON ..."
-(cd dist/nyash_compiler && ./nyash_compiler tmp/sample_exe_smoke.nyash > sample.json)
+(cd dist/nyash_compiler && timeout -s KILL 60s ./nyash_compiler tmp/sample_exe_smoke.nyash > sample.json)
+
+echo "[3.5/4] Validating JSON schema ..."
+python3 tools/validate_mir_json.py dist/nyash_compiler/sample.json
 
 if ! head -n1 dist/nyash_compiler/sample.json | grep -q '"kind":"Program"'; then
   echo "error: JSON does not look like a Program" >&2
@@ -26,7 +29,7 @@ echo "[4/4] Executing via bridge (pipe) to verify semantics ..."
 # Keep core minimal and deterministic
 export NYASH_DISABLE_PLUGINS=1
 set +e
-cat dist/nyash_compiler/sample.json | ./target/release/nyash --ny-parser-pipe --backend vm >/dev/null
+timeout -s KILL 60s bash -c 'cat dist/nyash_compiler/sample.json | ./target/release/nyash --ny-parser-pipe --backend vm >/dev/null'
 RC=$?
 set -e
 if [[ "$RC" -ne 7 ]]; then
@@ -36,4 +39,3 @@ fi
 
 echo "✅ EXE-first smoke passed (parser EXE + bridge run)"
 exit 0
-

tools/validate_mir_json.py

@@ -0,0 +1,57 @@
+#!/usr/bin/env python3
+"""
+Validate a MIR JSON file against the Nyash JSON v0 schema.
+
+Usage:
+  python3 tools/validate_mir_json.py <file.json> [--schema docs/reference/mir/json_v0.schema.json]
+
+Requires the 'jsonschema' Python package. Install via:
+  python3 -m pip install jsonschema
+"""
+
+import argparse
+import json
+import sys
+from pathlib import Path
+
+def main() -> int:
+    ap = argparse.ArgumentParser()
+    ap.add_argument('json_file', help='MIR JSON file path')
+    ap.add_argument('--schema', default='docs/reference/mir/json_v0.schema.json', help='Schema JSON path')
+    args = ap.parse_args()
+
+    try:
+        import jsonschema  # type: ignore
+    except Exception:
+        print('[schema] error: Python package "jsonschema" not found.\n'
+              'Install with: python3 -m pip install jsonschema', file=sys.stderr)
+        return 2
+
+    try:
+        with open(args.json_file, 'r', encoding='utf-8') as f:
+            data = json.load(f)
+    except Exception as e:
+        print(f'[schema] error: failed to read JSON: {e}', file=sys.stderr)
+        return 3
+
+    try:
+        with open(args.schema, 'r', encoding='utf-8') as f:
+            schema = json.load(f)
+    except Exception as e:
+        print(f'[schema] error: failed to read schema: {e}', file=sys.stderr)
+        return 4
+
+    try:
+        jsonschema.validate(instance=data, schema=schema)
+    except jsonschema.ValidationError as e:  # type: ignore
+        # Show human-friendly context
+        path = '/'.join([str(p) for p in e.path])
+        print(f'[schema] validation failed at $.{path}: {e.message}', file=sys.stderr)
+        return 5
+
+    print('[schema] validation OK')
+    return 0
+
+if __name__ == '__main__':
+    sys.exit(main())
+