Does what it says on the tin: lays out the fields, storing their offsets into the metadata, and initializes the size, flags, and stride of the value witness table.
Swift SVN r9120
We'll want to use the same logic to lay out generic struct fields at runtime. While we're here, fix a bug where we weren't aligning field offsets prior to storing them in the tuple metadata.
Swift SVN r9117
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
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
