Stage-A selfhost emitter fixes and LLVM opt toggle

tools/llvmlite_harness.py

@@ -31,6 +31,50 @@ except Exception:
 ROOT = _env_root or _default_root
 PY_BUILDER = ROOT / "src" / "llvm_py" / "llvm_builder.py"
 
+_OPT_ENV_KEYS = ("HAKO_LLVM_OPT_LEVEL", "NYASH_LLVM_OPT_LEVEL")
+
+def _parse_opt_level_env() -> int:
+    """Parse optimization level from env (0-3, default 2)."""
+    for key in _OPT_ENV_KEYS:
+        raw = os.environ.get(key)
+        if not raw:
+            continue
+        value = raw.strip()
+        if not value:
+            continue
+        upper = value.upper()
+        if upper.startswith("O"):
+            value = upper[1:]
+        try:
+            lvl = int(value)
+        except ValueError:
+            continue
+        if lvl < 0:
+            lvl = 0
+        if lvl > 3:
+            lvl = 3
+        return lvl
+    return 2
+
+def _resolve_llvm_opt_level():
+    level = _parse_opt_level_env()
+    try:
+        import llvmlite.binding as llvm_binding
+        names = {0: "None", 1: "Less", 2: "Default", 3: "Aggressive"}
+        attr = names.get(level, "Default")
+        enum = getattr(llvm_binding, "CodeGenOptLevel")
+        return getattr(enum, attr)
+    except Exception:
+        return level
+
+def _maybe_trace_opt(source: str) -> None:
+    if os.environ.get("NYASH_CLI_VERBOSE") == "1":
+        try:
+            level = _parse_opt_level_env()
+            print(f"[llvmlite harness] opt-level={level} ({source})", file=sys.stderr)
+        except Exception:
+            pass
+
 def run_dummy(out_path: str) -> None:
     # Minimal llvmlite program: ny_main() -> i32 0
     import llvmlite.ir as ir
@@ -52,7 +96,8 @@ def run_dummy(out_path: str) -> None:
     m = llvm.parse_assembly(str(mod))
     m.verify()
     target = llvm.Target.from_default_triple()
-    tm = target.create_target_machine()
+    tm = target.create_target_machine(opt=_resolve_llvm_opt_level())
+    _maybe_trace_opt("dummy")
     obj = tm.emit_object(m)
     Path(out_path).parent.mkdir(parents=True, exist_ok=True)
     with open(out_path, "wb") as f: