feat(traced_module): add visit method

GitOrigin-RevId: 251ecebf87c94fd5b60c27596a45149d479603e9

imperative/python/megengine/experimental/traced_module/traced_module.py

@@ -10,7 +10,7 @@ import collections
 import copy
 import functools
 from inspect import getmembers, isclass, ismethod
-from typing import List, Type
+from typing import Dict, List, Type
 
 from ... import module as M
 from ...core._imperative_rt.core2 import Tensor as RawTensor
@@ -64,6 +64,14 @@ class InternalGraph:
     def insert(self, expr):
         self._exprs.append(expr)
 
+    @property
+    def inputs(self):
+        return self._inputs
+
+    @property
+    def outputs(self):
+        return self._outputs
+
     def add_input(self, i):
         self._inputs.append(i)
 
@@ -271,6 +279,22 @@ class TracedModuleBuilder(NodeMixin):
             return wrapped
 
 
+class _expr_list:
+    def __init__(self, module: "TracedModule"):
+        self.module = module
+
+    def __iter__(self):
+        graph = self.module.m_node.graph
+        for expr in graph._exprs:
+            if isinstance(expr, CallMethod) and isinstance(expr.inputs[0], ModuleNode):
+                yield expr
+                assert isinstance(expr.inputs[0].expr, GetAttr)
+                (obj,) = expr.inputs[0].expr.interpret(self.module)
+                if isinstance(obj, TracedModule):
+                    yield from obj.exprs
+            yield expr
+
+
 class TracedModule(Module):
     """
     `TracedModule` is the Module created by tracing normal module. It owns a ModuleNode(m_node), and will interpret the m_node.graph when it is called.
@@ -291,14 +315,21 @@ class TracedModule(Module):
         return rst
 
     @property
-    def all_exprs(self):
+    def exprs(self):
+        """
+        Get all ``Expr`` s recursively.
+
+        :return: Iterator[Expr]
         """
-        Visit all ``Expr``s in the graph recursively.
+        return _expr_list(self)
 
-        :return: List[Expr]
+    def flatten(self):
         """
+        Get a new module, which eliminates ``GetAttr`` and has no hierarchy.
 
-        in_nodes = [i.expr for i in self.m_node.graph._inputs if not i is self]
+        :return: :class:`TracedModule`
+        """
+        new_module = copy.deepcopy(self)
 
         def _flatten_submodule(module, call=None):
             if not isinstance(module, TracedModule):
@@ -328,6 +359,7 @@ class TracedModule(Module):
                 elif isinstance(expr, CallMethod):
                     obj_node = expr.inputs[0]
                     if isinstance(obj_node, ModuleNode):
+                        assert isinstance(expr.inputs[0].expr, GetAttr)
                         (obj,) = expr.inputs[0].expr.interpret(module)
                         exprs.extend(_flatten_submodule(obj, expr))
                     else:
@@ -337,7 +369,9 @@ class TracedModule(Module):
 
             return exprs
 
-        return in_nodes + _flatten_submodule(self)
+        new_module.m_node.graph._exprs = _flatten_submodule(new_module)
+
+        return new_module
 
     def __getstate__(self):
         d = self.__dict__