[lldb] Handle storage nodes in TypeSystemSwiftTypeRef::IsAggregateType

[kastiglione]

Update TypeSystemSwiftTypeRef::IsAggregateType to match SwiftASTContext. This handles non-strong storage types (weak, unowned, unmanaged) by looking at the underlying type.

For example, given this top of a demangle tree:

kind=Global
  kind=TypeMangling
    kind=Type
      kind=Weak
        kind=Type
          kind=BoundGenericEnum

This code traverses past Weak and its child Type and then decides based on the node kind below that (BoundGenericEnum in this case).

rdar://73173573

[kastiglione]

@swift-ci test

[kastiglione]

To test this I am adding IsAggregateType to the SB API: https://reviews.llvm.org/D121252

[adrian-prantl]

This is good — is there any reason why we should handle why IsAggregateType handles Storage nodes and other Is... functions possibly don't? Should we peel them of in getCanonicalDemangleTree()?

[adrian-prantl]

In the short term consistency with SwiftASTContext is also a good goal, of course.

[kastiglione]

Should we peel them off in getCanonicalDemangleTree()?

I was asking myself this question too, and was going to bring it up. I think the next step is to try that suggestion, and see where tests fail.