Python binding to export bytecode format for lite interpreter (#32621)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/32621
Export the "_save_for_mobile" method to Python so that the bytecode format for lite interpreter can be added or updated to the original script model.
It's the first step of python binding for lite interpreter, as discussed in this [internal post](https://fb.workplace.com/groups/1144215345733672/permalink/1478900738931796/) and offline.
Next step is to export the load_for_mobile and run method of mobile module, so that users could verify the mobile model from Python.
Test: use the following python script to display the bytecode part of the updated model file.
```
#!/usr/bin/env python3
import sys
import pickle
import pprint
import zipfile
class FakeObject(object):
def __init__(self, module, name, args):
self.module = module
self.name = name
self.args = args
self.state = None
def __repr__(self):
state_str = "" if self.state is None else f"(state={self.state!r})"
return f"{self.module}.{self.name}{self.args!r}{state_str}"
def __setstate__(self, state):
self.state = state
class FakeClass(object):
def __init__(self, module, name):
self.module = module
self.name = name
self.__new__ = self.fake_new
def __repr__(self):
return f"{self.module}.{self.name}"
def __call__(self, *args):
return FakeObject(self.module, self.name, args)
def fake_new(self, *args):
return FakeObject(self.module, self.name, args)
class DumpUnpickler(pickle._Unpickler):
def find_class(self, module, name):
return FakeClass(module, name)
def persistent_load(self, pid):
return FakeObject("pers", "obj", (pid,))
def main(argv):
zfile = zipfile.ZipFile(argv[1])
names = [i for i in zfile.namelist() if "bytecode.pkl" in i]
if not names:
print("bytecode.pkl not found.")
return
with zfile.open(names[0], "r") as handle:
value = DumpUnpickler(handle).load()
pprint.pprint(value)
if __name__ == "__main__":
sys.exit(main(sys.argv))
```
Test Plan: Imported from OSS
Differential Revision: D19596359
Pulled By: iseeyuan
fbshipit-source-id: 19a4a771320f95217f5b0f031c2c04db7b4079a8
pytorch
c64dec19 - Python binding to export bytecode format for lite interpreter (#32621)
