support directly load the mask (#4144)

nni/compression/pytorch/speedup/compressor.py

 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT license.
-
+import os
 import queue
 import logging
 import copy
@@ -35,8 +35,8 @@ class ModelSpeedup:
             Note: The first dimension of the dummy_input should be the batchsize.
             The dummy input for ```jit.trace```, users should put it on the right
             device.
-        masks_file : str
-            The path of user provided mask file
+        masks_file : str/dict
+            The path of user provided mask file, or the mask object
         map_location : str
             the device on which masks are placed, same to map_location in ```torch.load```
         batch_dim : int
@@ -63,9 +63,13 @@ class ModelSpeedup:
         # load the mask tensor to the same device with the dummy_input
         # self.masks save the mask tensors pruned by the user and the infered
         # masks of the others modules
-        self.masks = torch.load(
-            masks_file, map_location if map_location is not None else str(self.device))
-
+        if isinstance(masks_file, str) and os.path.exists(masks_file):
+            self.masks = torch.load(
+                masks_file, map_location if map_location is not None else str(self.device))
+        elif isinstance(masks_file, dict):
+            self.masks = masks_file
+        else:
+            raise Exception('Please provide the mask or the path of the mask file')
         self.constant = {}
         # self.internal_result save the internal output of the submodules
         self.internal_result = {}