Phase 25.1a: selfhost builder hotfix (fn rename, docs)

tools/selfhost/README.md

@@ -29,3 +29,45 @@ Notes
 - Stage‑B emit uses either the Stage‑B entry or BuildBox（HAKO_USE_BUILDBOX=1 for emit-only）
 - Runner executes Core‑Direct in-proc under HAKO_CORE_DIRECT_INPROC=1.
 - For heavier cases (bundles/alias/require), keep Stage‑B canaries opt‑in in quick profile.
+
+---
+
+Stage1 Selfhost Binary (Phase 25.1 — initial wiring)
+
+Purpose
+- Provide a concrete Stage1 binary (`hakorune`) built from Hako sources.
+- Separate the Rust bootstrap binary (Stage0, `nyash`) from the Hakorune selfhost binary at the build-script level.
+
+Script
+- tools/selfhost/build_stage1.sh
+  - Builds a Stage1 selfhost executable from a Nyash/Hako entry point.
+  - Current entry (default):
+    - `lang/src/runner/launcher.hako` — Stage1 CLI launcher (commands: emit program-json/mir-json, etc.).
+  - Output:
+    - `target/selfhost/hakorune` by default.
+
+Usage
+```bash
+# Build Stage1 selfhost binary with defaults
+tools/selfhost/build_stage1.sh
+
+# Custom output path
+tools/selfhost/build_stage1.sh --out /tmp/hakorune-dev
+
+# Custom entry (experimental)
+tools/selfhost/build_stage1.sh --entry apps/selfhost-minimal/main.hako --out /tmp/hako_min
+```
+
+How it works
+- Pipeline:
+  1) Stage‑B + MirBuilder:
+     - `tools/hakorune_emit_mir.sh <entry.hako> <mir.json>`
+  2) LLVM EXE build:
+     - `tools/ny_mir_builder.sh --in <mir.json> --emit exe -o <exe>`
+- The Rust binary (Stage0) is resolved via the existing helpers inside `hakorune_emit_mir.sh` / `ny_mir_builder.sh`:
+  - Prefers `target/release/hakorune` when present.
+  - Falls back to `target/release/nyash` otherwise.
+
+Notes
+- This Stage1 binary is a minimal Ny Executor and not yet a full CLI replacement.
+- Full CLI / mode selection for Stage1 will be implemented in later phases; this script focuses on establishing the binary layout and build wiring.

tools/selfhost/build_stage1.sh

@@ -0,0 +1,89 @@
+#!/usr/bin/env bash
+# build_stage1.sh — Build Hakorune Stage1 selfhost binary
+#
+# Purpose
+# - Produce a minimal Stage1 (Hakorune selfhost) executable from Nyash/Hako sources.
+# - Current target is the Stage1 CLI launcher in lang/src/runner/launcher.hako.
+# - This is an initial implementation for Phase 25.1: binary layoutと Stage1 dev bin 用導線のみ。
+#
+# Output
+# - target/selfhost/hakorune (by default)
+#
+# Env / args
+# - HAKORUNE_STAGE1_ENTRY: override Stage1 entry .hako (optional).
+# - HAKORUNE_STAGE1_OUT:   override output path (optional).
+# - NYASH_LLVM_SKIP_BUILD: set to 1 to skip cargo build in ny_mir_builder.sh when artifacts already exist.
+# - Args:
+#     --out <path>   : override output path (same as HAKORUNE_STAGE1_OUT).
+#     --entry <file> : override entry .hako (same as HAKORUNE_STAGE1_ENTRY).
+#     -h|--help      : show usage and exit.
+#
+set -euo pipefail
+
+usage() {
+  cat <<'USAGE'
+build_stage1.sh — Build Hakorune Stage1 selfhost binary
+
+Usage:
+  tools/selfhost/build_stage1.sh [--out <exe_path>] [--entry <entry.hako>]
+
+Defaults:
+  entry .hako : lang/src/runner/launcher.hako
+  output exe  : target/selfhost/hakorune
+
+Notes:
+  - This script uses the Stage-B + MirBuilder pipeline:
+      lang/src/runner/launcher.hako
+        → tools/hakorune_emit_mir.sh (Program(JSON v0 → MIR JSON)
+        → tools/ny_mir_builder.sh --emit exe
+  - The Rust binary (Stage0) is treated as bootstrap and is resolved via
+    the existing helpers inside hakorune_emit_mir.sh / ny_mir_builder.sh.
+USAGE
+}
+
+ROOT="${NYASH_ROOT:-$(cd "$(dirname "$0")/../.." && pwd)}"
+
+ENTRY_DEFAULT="$ROOT/lang/src/runner/launcher.hako"
+OUT_DEFAULT="$ROOT/target/selfhost/hakorune"
+
+ENTRY="${HAKORUNE_STAGE1_ENTRY:-$ENTRY_DEFAULT}"
+OUT="${HAKORUNE_STAGE1_OUT:-$OUT_DEFAULT}"
+
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --out)
+      OUT="$2"
+      shift 2
+      ;;
+    --entry)
+      ENTRY="$2"
+      shift 2
+      ;;
+    -h|--help)
+      usage
+      exit 0
+      ;;
+    *)
+      echo "[stage1] unknown arg: $1" >&2
+      usage
+      exit 2
+      ;;
+  esac
+done
+
+if [ ! -f "$ENTRY" ]; then
+  echo "[stage1] entry .hako not found: $ENTRY" >&2
+  exit 2
+fi
+
+OUT_DIR="$(dirname "$OUT")"
+mkdir -p "$OUT_DIR"
+
+echo "[stage1] building Stage1 selfhost binary" >&2
+echo "         entry : $ENTRY" >&2
+echo "         output: $OUT" >&2
+
+# Use the Stage‑B → MirBuilder → ny-llvmc path
+NYASH_ROOT="$ROOT" bash "$ROOT/tools/selfhost_exe_stageb.sh" "$ENTRY" -o "$OUT"
+
+echo "[stage1] done: $OUT" >&2