...as detected by initializing an individual field without having
initialized the whole object (via `self = value`).
This only applies in pre-Swift-5 mode because the next commit will
treat all cross-module struct initializers as delegating in Swift 5.
This requires the witness table accessor function to gain two new parameters: a
pointer to an array of witness tables and their count. These are then passed down
to the instantiation function which reads them out of the array and writes them
into the newly-allocated witness table.
We use the count to assert that the number of conditional witness tables passed
in is what the protocol conformance expects, which is especially useful while
the feature is still experimental: it is a compiler/runtime bug if an incorrect
number is passed.
Switch most general endpoint to be `flags, parameters, parameterFlags, result`,
instead of opaque `void **`, more specialized ones to use follow argument scheme:
`flags, param0, [flags0], ..., paramN, [flagsN], result` and store parameter/flags
information separately in `FunctionCacheEntry::{Key, Data}` as well.
Currently only single 'inout' flag has been encoded into function
metadata, these changes extend function metadata to support up to
32 flags per parameter.
In the absence of conditional conformances, they are now extra types
with different constraints, plus extra overloads to the
stride(from:to:by:) and stride(from:through:by:).
Switch most general endpoint to be `flags, parameters, parameterFlags, result`,
instead of opaque `void **`, more specialized ones to use follow argument scheme:
`flags, param0, [flags0], ..., paramN, [flagsN], result` and store parameter/flags
information separately in `FunctionCacheEntry::{Key, Data}` as well.
Currently only single 'inout' flag has been encoded into function
metadata, these changes extend function metadata to support up to
32 flags per parameter.
This is a small code size win, and also gives us some abstraction so that future cooperative ObjC compilers/runtimes might be able to interoperate ObjC class objects with Swift type metadata efficiently than they currently are in the fragile Swift runtime.
While I'm here, I also noticed that swift_getObjCClassMetadata was unnecessarily getting exposed in non-ObjC-interop runtime builds, so I fixed that as well.
This is different from swift_deallocObject in that it applies to objects
at +1 while swift_deallocObject actually only applies to objects whose
state is deiniting (swift_release was called).
