The motivations here are that (1) the parametric types
that actually need the 'self' argument don't necessarily
all want to do what tuples do and put the VWT relative
to the metatype at some definable offset and (2)
recovering type parameters from the metatype is much
better defined than also hopping some relationship back.
Plus this allows VWTs to be shared across instances of
generic types. Also, I'm going to need to add a VW
that takes a metatype, and consistency seems right here.
If keeping two values live is actually punishing, I
might have to reconsider this. But the VWT is at least
always recoverable from the metatype, so....
I ended up abstracting the thing that GenHeap was doing
in order to save archetypes for arrays, because I
needed it to save metatypes instead of VWTs and because
it really needed abstractin'.
Swift SVN r3096
It does seem silly for this to all be templated, but I couldn't
really see a very elegant solution given how I wanted things to
be genericized.
...interestingly, a ?t.t[] type would have done nicely for some
of this.
Swift SVN r1807
heap allocations it makes, and switch swift_alloc over to pass
that pointer in as well as the alignment. Also, compute
whether a type is POD during its generation and cache that in
the object, and introduce a method on TypeInfo to destroy an
object in memory.
Swift SVN r1356
an owner attached. Use this to implement [byref(heap)]. Force
locals to the heap if they've been referenced in a way that requires
this.
Swift SVN r1265
