* Dynamic Cast Rework: Runtime
This is a completely refactored version of the core swift_dynamicCast
runtime method.
This fixes a number of bugs, especially in the handling of multiply-wrapped
types such as Optional within Any. The result should be much closer to the
behavior specified by `docs/DynamicCasting.md`.
Most of the type-specific logic is simply copied over from the
earlier implementation, but the overall structure has been changed
to be uniformly recursive. In particular, this provides uniform
handling of Optional, existentials, Any and other common "box"
types along all paths. The consistent structure should also be
easier to update in the future with new general types.
Benchmarking does not show any noticable performance implications.
**Temporarily**, the old implementation is still available. Setting the
environment variable `SWIFT_OLD_DYNAMIC_CAST_RUNTIME` before launching a program
will use the old runtime implementation. This is only to facilitate testing;
once the new implementation is stable, I expect to completely remove the old
implementation.
includes a number of QoI things to help people write the correct code. I will commit
the testcase for it as the next patch.
The bulk of this patch is moving the stdlib, testsuite and validation testsuite to
the new syntax. I moved a few uses of "as" patterns back to as? expressions in the
stdlib as well.
Swift SVN r27959
We have an SPI between the Swift compiler and Foundation based on the
SWIFT_SDK_OVERLAY_FOUNDATION_EPOCH preprocessor macro that allows us to
request the new API. rdar://20270080 tracks removing it.
Swift SVN r26475
This exposes an issue with CF types. Looking up their dynamic types gives us an ObjC class, which doesn't necessarily have the same protocol conformances (and for non-bridged types is just NSObject).
Swift SVN r23153
As a stopgap till IRGen properly emits indirected class references, support direct class reference protocol conformance records. This should get us to the point we can replace the dlsym hack with the new implementation.
Swift SVN r23073
We should unique foreign struct/enum metadata the same way we do CF foreign class metadata, but for now, treat them as direct references like we do in IRGen.
Swift SVN r23072
