Serializing from_node info in et serializer

devtools/etrecord/tests/etrecord_test.py

@@ -92,6 +92,17 @@ def check_graph_closeness(self, graph_a, graph_b):
                 self.assertEqual(
                     node_a.meta.get("debug_handle"), node_b.meta.get("debug_handle")
                 )
+                from_node_a = node_a.meta.get("from_node")
+                from_node_b = node_b.meta.get("from_node")
+
+                if from_node_a is None:
+                    self.assertIsNone(from_node_b)
+                else:
+                    self.assertIsNotNone(from_node_b)
+                    for node_source_a, node_source_b in zip(from_node_a, from_node_b):
+                        self.assertEqual(
+                            node_source_a.to_dict(), node_source_b.to_dict()
+                        )
 
     def test_etrecord_generation(self):
         captured_output, edge_output, et_output = self.get_test_model()

exir/serde/serialize.py

@@ -41,6 +41,7 @@
 )
 from torch._export.verifier import load_verifier
 from torch.fx.experimental import symbolic_shapes
+from torch.fx.traceback import NodeSource
 
 log: logging.Logger = logging.getLogger(__name__)
 
@@ -141,8 +142,24 @@ def serialize_metadata(self, node: torch.fx.Node) -> Dict[str, str]:
             debug_handle = node.meta["debug_handle"]
             meta["debug_handle"] = str(debug_handle)
 
+        if "from_node" in node.meta:
+            from_node = node.meta["from_node"]
+            # Serialize from_node as JSON since it's a complex nested structure
+            meta["from_node"] = json.dumps(self._make_from_node_json_acceptable(from_node))
+
         return meta
 
+    def _make_from_node_json_acceptable(self, from_node: Optional[List[NodeSource]]):
+        """
+        Serialize from_node metadata from a list of NodeSource objects to a list of dictionaries.
+        """
+        if from_node is None:
+            return None
+
+        json_acceptable_from_node = [node_source.to_dict() for node_source in from_node if isinstance(node_source, NodeSource)]
+
+        return json_acceptable_from_node
+
     def serialize_alloc_inputs(
         self, inputs  # pyre-ignore
     ) -> List[schema.NamedArgument]:
@@ -473,8 +490,22 @@ def deserialize_metadata(self, metadata: Dict[str, str]) -> Dict[str, Any]:
         if debug_handle := metadata.get("debug_handle"):
             res["debug_handle"] = int(debug_handle)
 
+        if from_node_str := metadata.get("from_node"):
+            res["from_node"] = self._deserialize_from_node(json.loads(from_node_str))
+
         return res
 
+    def _deserialize_from_node(self, from_node_data: Optional[List[Dict[str, Any]]]) -> Optional[List[NodeSource]]:
+        """
+        Recursively deserialize from_node metadata from JSON data.
+        """
+        if from_node_data is None:
+            return None
+
+        assert isinstance(from_node_data, list)
+
+        return [NodeSource._from_dict(fn_dict) for fn_dict in from_node_data]
+
     # pyre-ignore
     def deserialize_alloc_inputs(self, serialized_inputs: List[schema.NamedArgument]):
         def deserialize_alloc_spec(serialized_alloc_spec: str) -> memory.AllocSpec:

exir/tests/test_serde.py

@@ -275,3 +275,37 @@ def forward(self, x):
         )
         self.assertEqual(metadata[0], metadata_serde[0])
         self.assertEqual(list(metadata[1].keys()), list(metadata_serde[1].keys()))
+
+    def test_meta_debug_handle_and_from_node(self) -> None:
+        class Model(nn.Module):
+            def __init__(self):
+                super(Model, self).__init__()
+                self.conv_layer = nn.Conv2d(
+                    in_channels=1, out_channels=64, kernel_size=3, padding=1
+                )
+
+            def forward(self, x):
+                return self.conv_layer(x)
+
+        m = Model()
+        inputs = (torch.randn(1, 1, 32, 32),)
+
+        edge = to_edge(export(m, inputs, strict=True))
+        edge_new = deserialize(serialize(edge.exported_program()))
+        for node, node_new in zip(
+            edge.exported_program().graph_module.graph.nodes,
+            edge_new.graph_module.graph.nodes,
+        ):
+            if node.op not in {"placeholder", "output"}:
+                self.assertIsNotNone(node.meta.get("debug_handle"))
+                self.assertIsNotNone(node.meta.get("from_node"))
+                self.assertEqual(
+                    node.meta.get("debug_handle"), node_new.meta.get("debug_handle")
+                )
+                self.assertEqual(
+                    len(node.meta.get("from_node")), len(node_new.meta.get("from_node"))
+                )
+                for node_source, node_source_new in zip(
+                    node.meta.get("from_node"), node_new.meta.get("from_node")
+                ):
+                    self.assertEqual(node_source.to_dict(), node_source_new.to_dict())