Add Support to Dicts and Strings in ONNX for Inputs and Outputs (#25889)
Summary:
ONNX does not support dictionaries for inputs and output. The reason is that the arg flattening and unflattening does not handle Dictionary types.
This PR adds flattening/unflattening support for dictionaries and strings.
However this feature should be handled with caution for input dictionaries; and users need to verify their dict inputs carefully, and keep in mind that dynamic lookups are not available.
This PR will allow exporting cases where models have dictionnary outputs (detection and segmentation models in torchvision), and where dictionary inputs are used for model configurations (MultiScaleRoiAlign in torchvision).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/25889
Reviewed By: hl475
Differential Revision: D17613605
Pulled By: houseroad
fbshipit-source-id: c62da4f35e5dc2aa23a85dfd5e2e11f63e9174db
