stage3: unify to cleanup; MIR return-defer; docs+smokes updated; LLVM(harness): finalize_phis ownership, ret.py simplified, uses-predeclare; cleanup return override green; method-postfix cleanup return WIP (PHI head)

src/llvm_py/tests/test_phi_tagging.py

@@ -0,0 +1,80 @@
+import unittest
+import llvmlite.ir as ir
+
+from src.llvm_py.phi_wiring import setup_phi_placeholders
+
+
+class DummyResolver:
+    def __init__(self):
+        self.marked = set()
+
+    def mark_string(self, vid: int):
+        self.marked.add(int(vid))
+
+
+class DummyBuilder:
+    def __init__(self, bb_map):
+        self.i64 = ir.IntType(64)
+        self.vmap = {}
+        self.def_blocks = {}
+        self.resolver = DummyResolver()
+        self.bb_map = bb_map
+
+
+class TestPhiTagging(unittest.TestCase):
+    def _mk_blocks_and_bbs(self):
+        mod = ir.Module(name="m")
+        fnty = ir.FunctionType(ir.VoidType(), [])
+        fn = ir.Function(mod, fnty, name="f")
+        b0 = fn.append_basic_block(name="b0")
+        b1 = fn.append_basic_block(name="b1")
+        return mod, {0: b0, 1: b1}
+
+    def test_mark_by_dst_type(self):
+        _mod, bb_map = self._mk_blocks_and_bbs()
+        builder = DummyBuilder(bb_map)
+        blocks = [
+            {
+                "id": 1,
+                "instructions": [
+                    {
+                        "op": "phi",
+                        "dst": 42,
+                        "dst_type": {"kind": "handle", "box_type": "StringBox"},
+                        "incoming": [[7, 0]],
+                    }
+                ],
+            }
+        ]
+        setup_phi_placeholders(builder, blocks)
+        self.assertIn(42, builder.resolver.marked)
+
+    def test_mark_by_incoming_stringish(self):
+        _mod, bb_map = self._mk_blocks_and_bbs()
+        builder = DummyBuilder(bb_map)
+        blocks = [
+            {
+                "id": 0,
+                "instructions": [
+                    {"op": "const", "dst": 7, "value": {"type": "string", "value": "hi"}}
+                ],
+            },
+            {
+                "id": 1,
+                "instructions": [
+                    {
+                        "op": "phi",
+                        "dst": 43,
+                        # no dst_type string; inference should happen via incoming
+                        "incoming": [[7, 0]],
+                    }
+                ],
+            },
+        ]
+        setup_phi_placeholders(builder, blocks)
+        self.assertIn(43, builder.resolver.marked)
+
+
+if __name__ == "__main__":
+    unittest.main()
+