[TS2E] Remove reference to torch.onnx internals (#132186)

Instead, this PR moves the code to the converter to avoid dependence. Feel free to refactor it afterward.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/132186
Approved by: https://github.com/angelayi

torch/_export/converter.py

@@ -2,12 +2,14 @@
 import builtins
 import logging
 import operator
+import typing
 import warnings
 from contextlib import contextmanager
-from typing import Any, Dict, List, Optional, Set, Tuple, Union
+from typing import Any, Dict, List, Optional, Sequence, Set, Tuple, Union
 
 import torch
 import torch.export._trace
+from torch import _C
 from torch.export.exported_program import ExportedProgram
 from torch.export.graph_signature import (
     ConstantArgument,
@@ -18,12 +20,101 @@ from torch.export.graph_signature import (
     TensorArgument,
 )
 from torch.fx import subgraph_rewriter
-from torch.onnx.utils import _create_jit_graph
 
 
 log = logging.getLogger(__name__)
 
 
+def _get_param_count_list(method_graph, args_params):
+    param_count_list = []
+    for input_, arg_params_ in zip(method_graph.inputs(), args_params):
+        if "PackedParams" in str(input_.type()):
+            in_vars, _ = torch.jit._flatten(arg_params_)
+            param_count_list.append(len(in_vars))
+        else:
+            param_count_list.append(arg_params_ is not None)
+
+    return param_count_list
+
+
+def _trace_and_get_graph_from_model(model, args):
+    # A basic sanity check: make sure the state_dict keys are the same
+    # before and after running the model.  Fail fast!
+    orig_state_dict_keys = torch.jit._unique_state_dict(model).keys()
+
+    # Disable Autocast cache because it replaces kernel's weight and bias
+    # by (undesired) constants.
+    # No perf impact for when there are reused weights since https://github.com/pytorch/pytorch/pull/85665
+    prev_autocast_cache_enabled = torch.is_autocast_cache_enabled()
+    torch.set_autocast_cache_enabled(False)
+    trace_graph, torch_out, inputs_states = torch.jit._get_trace_graph(
+        model,
+        args,
+        strict=False,
+        _force_outplace=False,
+        _return_inputs_states=True,
+    )
+    torch.set_autocast_cache_enabled(prev_autocast_cache_enabled)
+
+    if orig_state_dict_keys != torch.jit._unique_state_dict(model).keys():
+        raise RuntimeError(
+            "state_dict changed after running the tracer; "
+            "something weird is happening in your model!"
+        )
+
+    return trace_graph, torch_out
+
+
+def _create_jit_graph(
+    model: Union[torch.nn.Module, torch.jit.ScriptFunction], args: Sequence[Any]
+) -> Tuple[torch.Graph, List["_C.IValue"], Any, Optional[torch.ScriptModule]]:
+    if isinstance(model, (torch.jit.ScriptFunction, torch.jit.ScriptModule)):
+        flattened_args = tuple(torch.jit._flatten(tuple(args))[0])
+        torch_out = None
+
+        if isinstance(model, torch.jit.ScriptModule):
+            try:
+                graph = model.forward.graph  # type: ignore[attr-defined]
+            except AttributeError as e:
+                raise RuntimeError("'forward' method must be a script method") from e
+            _C._jit_pass_onnx_function_substitution(graph)
+            freezed_module = _C._freeze_module(
+                typing.cast(_C.ScriptModule, model._c), preserveParameters=True
+            )
+            module, params = _C._jit_onnx_list_model_parameters(freezed_module)
+            method_graph = module._get_method("forward").graph
+            args_params = tuple(args) + tuple(params)
+            param_count_list = _get_param_count_list(method_graph, args_params)
+            in_vars, _ = torch.jit._flatten(args_params)
+            graph = _C._propagate_and_assign_input_shapes(
+                method_graph, tuple(in_vars), param_count_list, False, False
+            )
+            return graph, params, torch_out, module
+
+        # torch.jit.ScriptFunction
+        params = []
+        graph = model.graph
+        _C._jit_pass_onnx_function_substitution(graph)
+        param_count_list = _get_param_count_list(graph, args)
+        graph = _C._propagate_and_assign_input_shapes(
+            graph, flattened_args, param_count_list, False, False
+        )
+        return graph, params, torch_out, None
+
+    graph, torch_out = _trace_and_get_graph_from_model(model, args)
+    _C._jit_pass_onnx_lint(graph)
+    state_dict = torch.jit._unique_state_dict(model)
+    params = list(state_dict.values())
+    graph_inputs = list(graph.inputs())
+    user_input_num = len(graph_inputs) - len(state_dict)
+    param_names = list(state_dict.keys())
+    for i, inp in enumerate(graph_inputs):
+        if i >= user_input_num:
+            inp.setDebugName(param_names[i - user_input_num])
+    _C._jit_pass_onnx_function_substitution(graph)
+    return graph, params, torch_out, None
+
+
 def inplace_optimize_sym_size_div(gm: torch.fx.GraphModule):
     def pattern(im, dim, scale):
         sym_size_int = torch.ops.aten.sym_size.int(im, dim)