submodule swapping via module interface (#28409)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/28409
This PR enables submodule swapping via module interface. User could
declare a submodule as an module interface type in the ScriptModule,
during compilation we will record the module interface type in
ModuleInfo of ConcreteModuleType, the JIT type associated will have the
correct ModuleInterfaceType, and CppModule will get the correct module list
Given that we still keep the module interface type in the type system,
the graph is not inlined when we call Module::Attr and it will use
prim::CallMethod to call the method, this allow us to do module swapping
for the ScriptModule that also meet the same module interface type, and
we only allow the module swapping through the module interface
approach.
Test Plan: Imported from OSS
Reviewed By: driazati
Differential Revision: D18284309
fbshipit-source-id: 2cb843e4b75fa3fcd8c6020832a81014dbff4f03
