[Executorch][Export][2/N] Add to_edge and to_backend stages

Pull Request resolved: #12937

Address (6) in the rfc: #12660

1. Adds stage implementations for `to_edge` and `to_backend`
2. Adds unit tests for the two stages
3. Adds these two stages in the validation pipeline.

Fixes #12932
ghstack-source-id: 299959405
@exported-using-ghexport

Differential Revision: [D79120576](https://our.internmc.facebook.com/intern/diff/D79120576/)

Author: abhinaykukkadapu

export/export.py

@@ -24,6 +24,8 @@
     QuantizeStage,
     SourceTransformStage,
     Stage,
+    ToBackendStage,
+    ToEdgeStage,
     TorchExportStage,
 )
 from .types import StageType
@@ -147,7 +149,9 @@ def __init__(
         )
 
         # Stage registry: map of StageType to Stage instances
-        self._stage_registry: Dict[StageType, Stage] = self._build_default_stages()
+        self._stage_registry: Dict[StageType, Stage] = self._build_stages(
+            self._pipeline_stages
+        )
 
         # Intialize run context
         self._run_context: Dict[str, Any] = {
@@ -170,10 +174,12 @@ def _get_default_pipeline(self) -> List[StageType]:
             StageType.TO_EXECUTORCH,
         ]
 
-    def _build_default_stages(self) -> Dict[StageType, Stage]:
+    def _build_stages(self, stages: List[StageType]) -> Dict[StageType, Stage]:
+        """Build the stage registry from the given stages."""
         stage_registry: Dict[StageType, Stage] = {}
 
-        for stage_type in self._get_default_pipeline():
+        stage = None
+        for stage_type in stages or self._get_default_pipeline():
             if stage_type == StageType.SOURCE_TRANSFORM:
                 stage = SourceTransformStage(self._quant_recipe)
             elif stage_type == StageType.QUANTIZE:
@@ -191,12 +197,24 @@ def _build_default_stages(self) -> Dict[StageType, Stage]:
                     transform_passes=self._export_recipe.edge_transform_passes,
                     compile_config=self._export_recipe.edge_compile_config,
                 )
+            elif stage_type == StageType.TO_EDGE:
+                stage = ToEdgeStage(
+                    edge_compile_config=self._export_recipe.edge_compile_config
+                )
+            elif stage_type == StageType.TO_BACKEND:
+                stage = ToBackendStage(
+                    partitioners=self._export_recipe.partitioners,
+                    transform_passes=self._export_recipe.edge_transform_passes,
+                )
             elif stage_type == StageType.TO_EXECUTORCH:
                 stage = ExecutorchStage(self._export_recipe.executorch_backend_config)
             else:
-                raise ValueError(f"Unknown stage type: {stage_type}")
+                logging.info(
+                    f"{stage_type} is unknown, you have to register it before executing export()"
+                )
 
-            stage_registry[stage_type] = stage
+            if stage:
+                stage_registry[stage_type] = stage
         return stage_registry
 
     def register_stage(self, stage_type: StageType, stage: Stage) -> None:
@@ -241,7 +259,9 @@ def _validate_pipeline_sequence(
         first_stage = stages[0]
         first_stage_instance = self._stage_registry.get(first_stage)
         if first_stage_instance is None:
-            raise ValueError(f"Stage {first_stage} not found in registry")
+            raise ValueError(
+                f"Stage {first_stage} not found in registry, register it using session.register_stage()"
+            )
 
         if not first_stage_instance.can_start_pipeline:
             raise ValueError(f"Stage {first_stage} cannot start a pipeline. ")
@@ -254,7 +274,9 @@ def _validate_pipeline_sequence(
             # Get the stage instance to check its valid predecessors
             stage_instance = self._stage_registry.get(current_stage)
             if stage_instance is None:
-                raise ValueError(f"Stage {current_stage} not found in registry")
+                raise ValueError(
+                    f"Stage {current_stage} not found in registry, , register it using session.register_stage()"
+                )
 
             valid_predecessors = stage_instance.valid_predecessor_stages
 

export/stages.py

@@ -10,8 +10,9 @@
 
 import torch
 from executorch.devtools.backend_debug import get_delegation_info
+from executorch.exir import EdgeCompileConfig
 from executorch.exir.backend.backend_api import validation_disabled
-from executorch.exir.program import to_edge_transform_and_lower
+from executorch.exir.program import to_edge, to_edge_transform_and_lower
 from executorch.exir.program._program import _transform
 from executorch.export.recipe import QuantizationRecipe
 from executorch.export.types import StageType
@@ -223,7 +224,7 @@ def stage_type(self) -> str:
 
     @property
     def valid_predecessor_stages(self) -> List["StageType"]:
-        return [StageType.TO_EDGE_TRANSFORM_AND_LOWER]
+        return [StageType.TO_EDGE_TRANSFORM_AND_LOWER, StageType.TO_BACKEND]
 
     @property
     def can_start_pipeline(self) -> bool:
@@ -354,3 +355,114 @@ def run(self, artifact: PipelineArtifact) -> None:
             quantized_models[method_name] = quantized_model
 
         self._artifact = artifact.copy_with_new_data(quantized_models)
+
+
+class ToEdgeStage(Stage):
+    """
+    Stage: Convert ExportedProgram to EdgeProgramManager.
+    """
+
+    def __init__(
+        self,
+        edge_compile_config: Optional[EdgeCompileConfig] = None,  # pyre-ignore
+    ) -> None:
+        super().__init__()
+        self._edge_compile_config = edge_compile_config
+
+    @property
+    def stage_type(self) -> str:
+        return StageType.TO_EDGE
+
+    @property
+    def valid_predecessor_stages(self) -> List["StageType"]:
+        return [StageType.TORCH_EXPORT]
+
+    @property
+    def can_start_pipeline(self) -> bool:
+        return False
+
+    def run(self, artifact: PipelineArtifact) -> None:
+        """
+        Convert ExportedProgram to EdgeProgramManager.
+
+        Args:
+            artifact: Contains exported programs and context
+        """
+        exported_programs = artifact.data
+        constant_methods = artifact.get_context("constant_methods")
+
+        # Convert to edge program manager
+        edge_program_manager = to_edge(
+            exported_programs,
+            constant_methods=constant_methods,
+            compile_config=self._edge_compile_config,
+        )
+
+        self._artifact = artifact.copy_with_new_data(edge_program_manager)
+
+
+class ToBackendStage(Stage):
+    """
+    Stage: Apply transformations and partitioning to EdgeProgramManager.
+    """
+
+    def __init__(
+        self,
+        partitioners: Optional[List[Any]] = None,
+        transform_passes: Optional[Sequence[Callable[[Any], Optional[Any]]]] = None,
+    ) -> None:
+        super().__init__()
+        self._partitioners = partitioners
+        self._transform_passes = transform_passes
+
+    @property
+    def stage_type(self) -> str:
+        return StageType.TO_BACKEND
+
+    @property
+    def valid_predecessor_stages(self) -> List["StageType"]:
+        return [StageType.TO_EDGE]
+
+    @property
+    def can_start_pipeline(self) -> bool:
+        return False
+
+    def run(self, artifact: PipelineArtifact) -> None:
+        """
+        Apply transformations and partitioning to EdgeProgramManager.
+
+        Args:
+            artifact: Contains edge program manager and context
+        """
+        edge_program_manager = artifact.data
+
+        if edge_program_manager is None:
+            raise RuntimeError("Edge program manager is not set.")
+
+        # Apply transform passes if available
+        if self._transform_passes:
+            edge_program_manager = edge_program_manager.transform(
+                self._transform_passes
+            )
+
+        # Apply partitioners if available
+        if self._partitioners is not None and len(self._partitioners) > 0:
+            with validation_disabled():
+                # pyre-ignore
+                for partitioner in self._partitioners:
+                    edge_program_manager = edge_program_manager.to_backend(partitioner)
+
+        # Get delegation info
+        delegation_info = get_delegation_info(
+            edge_program_manager.exported_program().graph_module
+        )
+
+        self._artifact = artifact.copy_with_new_data(edge_program_manager)
+        self._artifact.add_context("delegation_info", delegation_info)
+
+    @property
+    def delegation_info(self) -> Any:
+        """
+        Returns the delegation info.
+        """
+        return self._artifact.get_context("delegation_info")

export/tests/test_export_session.py

@@ -249,14 +249,23 @@ def _get_export_session(self, stages: List[StageType]):
     def test_valid_pipeline_sequences(self) -> None:
         """Test various valid pipeline sequences."""
         valid_sequences = [
-            # Full pipeline
+            # Full pipeline with to_edge_transform_lower
             [
                 StageType.SOURCE_TRANSFORM,
                 StageType.QUANTIZE,
                 StageType.TORCH_EXPORT,
                 StageType.TO_EDGE_TRANSFORM_AND_LOWER,
                 StageType.TO_EXECUTORCH,
             ],
+            # Full pipeline with to_edge, to_backend
+            [
+                StageType.SOURCE_TRANSFORM,
+                StageType.QUANTIZE,
+                StageType.TORCH_EXPORT,
+                StageType.TO_EDGE,
+                StageType.TO_BACKEND,
+                StageType.TO_EXECUTORCH,
+            ],
             # Skip quantize
             [
                 StageType.SOURCE_TRANSFORM,

export/tests/test_export_stages.py

@@ -19,6 +19,8 @@
     QuantizeStage,
     SourceTransformStage,
     StageType,
+    ToBackendStage,
+    ToEdgeStage,
     TorchExportStage,
 )
 from torch.export import ExportedProgram
@@ -282,3 +284,105 @@ def test_run_empty_example_inputs(self) -> None:
         self.assertIn(
             "Example inputs for method forward not found or empty", str(cm.exception)
         )
+
+
+class TestToEdgeStage(unittest.TestCase):
+    def setUp(self) -> None:
+        self.mock_exported_program = Mock(spec=ExportedProgram)
+        self.exported_programs = {"forward": self.mock_exported_program}
+        self.context = {"constant_methods": None}
+
+    @patch("executorch.export.stages.to_edge")
+    def test_run_success(self, mock_to_edge: Mock) -> None:
+        mock_edge_manager = Mock(spec=EdgeProgramManager)
+        mock_to_edge.return_value = mock_edge_manager
+        mock_config = Mock()
+
+        stage = ToEdgeStage(edge_compile_config=mock_config)
+        artifact = PipelineArtifact(data=self.exported_programs, context=self.context)
+        stage.run(artifact)
+
+        # Verify to_edge was called with correct parameters
+        mock_to_edge.assert_called_once_with(
+            self.exported_programs,
+            constant_methods=None,
+            compile_config=mock_config,
+        )
+
+        # Verify artifacts are set correctly
+        result_artifact = stage.get_artifacts()
+        self.assertEqual(result_artifact.data, mock_edge_manager)
+
+
+class TestToBackendStage(unittest.TestCase):
+    def setUp(self) -> None:
+        self.mock_edge_manager = Mock(spec=EdgeProgramManager)
+        self.context = {}
+
+    @patch("executorch.export.stages.get_delegation_info")
+    def test_run_success_no_transforms_or_partitioners(
+        self, mock_get_delegation_info: Mock
+    ) -> None:
+        # Test successful execution without transforms or partitioners
+        mock_delegation_info = {"delegation": "info"}
+        mock_get_delegation_info.return_value = mock_delegation_info
+        mock_exported_program = Mock()
+        mock_graph_module = Mock()
+        mock_exported_program.graph_module = mock_graph_module
+        self.mock_edge_manager.exported_program.return_value = mock_exported_program
+
+        stage = ToBackendStage()
+        artifact = PipelineArtifact(data=self.mock_edge_manager, context=self.context)
+        stage.run(artifact)
+
+        # Verify get_delegation_info was called
+        mock_get_delegation_info.assert_called_once_with(mock_graph_module)
+
+        # Verify artifacts are set correctly
+        result_artifact = stage.get_artifacts()
+        self.assertEqual(result_artifact.data, self.mock_edge_manager)
+        self.assertEqual(
+            result_artifact.get_context("delegation_info"), mock_delegation_info
+        )
+
+    @patch("executorch.export.stages.get_delegation_info")
+    def test_run_with_partitioners_and_passes(
+        self, mock_get_delegation_info: Mock
+    ) -> None:
+        mock_delegation_info = {"delegation": "info"}
+        mock_get_delegation_info.return_value = mock_delegation_info
+        mock_exported_program = Mock()
+        mock_graph_module = Mock()
+        mock_exported_program.graph_module = mock_graph_module
+
+        mock_edge_program_manager = Mock(spec=EdgeProgramManager)
+        mock_edge_program_manager.transform.return_value = mock_edge_program_manager
+        mock_edge_program_manager.to_backend.return_value = mock_edge_program_manager
+
+        mock_partitioner = Mock()
+        mock_transform_passes = [Mock(), Mock()]
+        stage = ToBackendStage(
+            partitioners=[mock_partitioner], transform_passes=mock_transform_passes
+        )
+        artifact = PipelineArtifact(
+            data=mock_edge_program_manager, context=self.context
+        )
+        stage.run(artifact)
+
+        # Verify transform and to_backend called correctly
+        mock_edge_program_manager.transform.assert_called_once_with(
+            mock_transform_passes
+        )
+        mock_edge_program_manager.to_backend.assert_called_once_with(mock_partitioner)
+
+        # Verify artifacts contain the backend manager
+        result_artifact = stage.get_artifacts()
+        self.assertEqual(result_artifact.data, mock_edge_program_manager)
+
+    def test_run_edge_manager_none(self) -> None:
+        stage = ToBackendStage()
+        artifact = PipelineArtifact(data=None, context=self.context)
+
+        with self.assertRaises(RuntimeError) as cm:
+            stage.run(artifact)
+        self.assertIn("Edge program manager is not set", str(cm.exception))

export/types.py

@@ -11,8 +11,11 @@ class StageType(str, Enum):
     """
     Enum representing the different stages in the ExecuTorch export pipeline.
     """
+
     SOURCE_TRANSFORM = "source_transform"
     QUANTIZE = "quantize"
     TORCH_EXPORT = "torch_export"
     TO_EDGE_TRANSFORM_AND_LOWER = "to_edge_transform_and_lower"
+    TO_EDGE = "to_edge"
+    TO_BACKEND = "to_backend"
     TO_EXECUTORCH = "to_executorch"