This patch adds initial version of `FortranObjectViewOpInterface`
that helps walking def-use chains containing "pass-through"
operations (like `fir.convert`, etc.). The new interface is used
in FIR AliasAnalysis to demonstrate potential usage (I know we have
such walks elsewhere in Flang, but I am only changing FIR AliasAnalysis
in this patch).
This is an NFC change. I noticed that if I remove followBoxData
code there are no failing LIT tests, but I decided to keep it
in order to keep the change looking more like NFC.
This change is a follow-up on the discussion in #164020:
it is unclear if the `FortranObjectViewOpInterface` methods and their
usage, as in this patch, apply to the ViewLike operations that
use the core MLIR `ViewLikeOpInterface`. So this patch is the path
towards simplifying Flang code while also enabling a future discussion
about having such an interface in core MLIR.
be717af693