Summary:
This diff uses a type parameter of `Provider.get` to decide whether assigning expensive cost to the
function call or not. For example, if the type is small one like `Provider<Integer>`, it be
evaluated to have a unit cost, otherwise a linear cost.
To get the return type of `Provider.get`, I added a simple analyzer that collects "casted" types
backwards. In Sil, while the function call statement loses the return type, e.g,
```
n$5=_fun_Object Provider.get()(n$3:javax.inject.Provider*);
```
the `n$5`'s value is usually casted to a specific type at some point later.
```
*&$irvar0:java.lang.Object*=n$5
n$8=*&$irvar0:java.lang.Object*
n$9=_fun___cast(n$8:java.lang.Object*,sizeof(t=java.lang.Integer;sub_t=( sub )(cast)):void)
```
So, the analyzer starts from the cast statements backward, collecting the types to cast for each
variables.
Reviewed By: ezgicicek
Differential Revision: D20345268
fbshipit-source-id: 704b42ec1
Sungkeun Cho