Old Swift and new Swift runtimes and overlays need to coexist in the same process. This means there must not be any classes which have the same ObjC runtime name in old and new, because the ObjC runtime doesn't like name collisions.
When possible without breaking source compatibility, classes were renamed in Swift, which results in a different ObjC name.
Public classes were renamed only on the ObjC side using the @_objcRuntimeName attribute.
This is similar to the work done in pull request #19295. That only renamed @objc classes. This renames all of the others, since even pure Swift classes still get an ObjC name.
rdar://problem/46646438
Like before, allow the use of Cocoa indices to access native sets/dictionaries, but approximate the same mutation count-based check as we do for native indices.
- Ensure that native collections that were converted from Cocoa have an age generated from the address of the original Cocoa object.
- To get the age of a Cocoa index, regenerate one from the object embedded in it.
- Compare self.age to index.age and trap if it doesn’t match.
# Conflicts:
# stdlib/public/core/HashTable.swift
Native sets and (especially!) native dictionaries must support indexing with Cocoa indices — indices must be preserved when a Cocoa set/dictionary is converted to native.
This is especially the case for Dictionaries that were converted because of a mutation restricted to values — such as those done through the Values view.
The mutation count will allow us to recognize and trap on invalid indices more reliably. (However, it won’t be foolproof — some invalid indices may pass through the checks.)
- Change _scale to Int8 to make space for an extra Int32 without enlarging the storage header.
- Add an _age field inside the new gap.
- Initialize the age to a scrambled version of the storage address.
- Generate a new counter for every newly allocated storage instance, except for identical copy-on-write copies.
- Increment the mutation counter after every removal.
Add __consuming and __owned to Set and Dictionary members where applicable.
Ignore compiler intrinsics for casting for now — their ARC behavior is covered by unit tests that need to be updated.
