Update the design document to reflect the actual implementation
of polymorphic entities.
Reviewed By: jeanPerier, PeteSteinfeld
Differential Revision: https://reviews.llvm.org/D147665
When allocating a polymorphic entity, its type descriptor can come
from the declared type or can be provided in the allocate statement.
This patch adds lowering for allocate on polymorphic by calling
the `AllocatableInitDerived` runtime function with the correct
type descriptor. Some adaptation are made in the code generation
to accept fir.class where it is appropriate.
Reviewed By: jeanPerier
Differential Revision: https://reviews.llvm.org/D136426
This document aims to give insights at the representation of polymorphic
entities in FIR and how polymorphic related constructs and features are lowered
to FIR.
Reviewed By: klausler, razvanlupusoru
Differential Revision: https://reviews.llvm.org/D131515