Although I don't plan to bring over new assertions wholesale
into the current qualification branch, it's entirely possible
that various minor changes in main will use the new assertions;
having this basic support in the release branch will simplify that.
(This is why I'm adding the includes as a separate pass from
rewriting the individual assertions)
Compute, update and handle borrowed-from instruction in various utilities and passes.
Also, used borrowed-from to simplify `gatherBorrowIntroducers` and `gatherEnclosingValues`.
Replace those utilities by `Value.getBorrowIntroducers` and `Value.getEnclosingValues`, which return a lazily computed Sequence of borrowed/enclosing values.
In the absence of this bailout, reborrows can be introduced while replacing the @owned value with
a local borrow introducer. Since lifetime adjustment for this case was not implemented, disable here.
rdar://106757446
Andy some time ago already created the new API but didn't go through and update
the old occurences. I did that in this PR and then deprecated the old API. The
tree is clean, so I could just remove it, but I decided to be nicer to
downstream people by deprecating it first.
The specific problem here is that I am going to be adding some code to
SemanticARCOpts that eliminates reborrows and may need to create new phi
arguments and thus add arguments to edges. The weird thing about this is that
doing so actually requires us to create a new terminator!
This means that subtle pointer invalidation issues can occur here. To work
around that we store our terminators as SILBasicBlock, operand number since we
can always immediately find a terminator from its basic block. If we do not have
a terminator, we keep on just storing the SILInstruction itself.
NOTE: This only saves us from additive changes. Deletions are still an issue.
This makes it easier to understand conceptually why a ValueOwnershipKind with
Any ownership is invalid and also allowed me to explicitly document the lattice
that relates ownership constraints/value ownership kinds.
This patch moves state from the main SemanticARCOptVisitor struct to instead be
on a context object. Sub-transformations should not need to know about the
visitor since how it processes things is orthogonal from the transformations
themselves.
