[dynamo] support custom __getattr__ on torch.nn.Modules (#94658)
**Summary**: torch.nn.Module implementations previously did not support custom implementations of `__getattr__`; if a torch.nn.Module subclass implemented `__getattr__` and we tried to access an attribute that was expected to be present in `__getattr__`, dynamo would not check `__getattr__` and would error out with an AttributeError. This PR copies the functionality from UserDefinedObjectVariable into torch.nn.Module so that it also supports `__getattr__`
Example of a module which previously would fail:
```python
class MyMod(torch.nn.Module):
def __init__(self):
super().__init__()
self.custom_dict = {"queue": [torch.rand((2, 2)) for _ in range(3)]}
self.other_attr = torch.rand((2, 2))
def __getattr__(self, name):
custom_dict = self.custom_dict
if name in custom_dict:
return custom_dict[name]
return super().__getattr__(name)
def forward(self, x):
return x @ self.other_attr + self.queue[-1]
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/94658
Approved by: https://github.com/yanboliang, https://github.com/jansel
