If a single-payload union doesn't use up all of its payload's extra inhabitants, it can claim the remaining ones as its own. While we're here, specialize the extra inhabitants implementation for no-payload unions to generously (and more efficiently) give out all integer values within its storage type above the largest discriminator as extra inhabitants, instead of relying entirely on the spare bits mask.
Swift SVN r8470
Add functions to dynamically query the extra inhabitants of a single-payload union's payload metadata, then identify or store bit patterns used to represent empty cases, whether they happen to use extra inhabitants or added tag bits.
Swift SVN r8320
Instead of hardcoding a walk of a list of fill ops, have generic metadata templates carry a pointer to a fill function for swift_getGenericMetadata to invoke to perform the fill operations. For types with dynamic layout, we will need to be able to perform more complex fill operations than a simple transfer of arguments into generic metadata slots.
Swift SVN r7893
Instead of letting swift_NSStringToString leak malloced memory, use swift_allocPOD to allocate storage for the converted String, and stash the heap object into the created string.
Swift SVN r7872
swift_allocPOD allocates a heap object capable of holding POD data of some given size and alignment. This will allow 'alloc_box' and 'alloc_array' to lower specially without instantiating do-nothing heap metadata for POD types, as described in <rdar://problem/13129334>. Update the dynamic swift_allocBox entry point to use swift_allocPOD for POD types. This can also be used by other runtime functions that need to allocate reference-counted scratch memory, such as swift_NSStringToString, as noted in <rdar://problem/14646715>.
Swift SVN r7860
We haven't fully updated references to union cases, and enums still are not
their own thing yet, but "oneof" is gone. Long live "union"!
Swift SVN r6783
