Summary: Add a second form for OIL AoT compilation which returns a `std::optional` instead of throwing. This is preferred if it's possible for the symbol to not be defined and you must not throw, instead preferring to handle the failure a different way. This still calls the throwing interface as that's what oilgen depends on, but makes sure the precondition is true first such that it won't throw.
Differential Revision: D50363926
Summary:
Update `OIGenerator` and out BUCK stuff for compile time OIL with OIL v2. Main things:
- Switch `OIGenerator` from the `getObjectSize` call to the new `introspect` call.
- Switch from looking at template parameters to looking at function parameters, as this was exposing a bug in our elfutils/drgn and this way it's the same as OID.
- Migrate `OIGenerator` to CodeGen v2 and update CodeGen v2 to accept a linkage name.
- Update the compile time example to be the same as the JIT example, using the new interface and the JSON exporter.
- Clean up the `ObjectIntrospection.h` header.
Differential Revision: D48687728
fbshipit-source-id: 2c3c041fd1b6499c5e02eb5e2082a977bfa529d7
