Replace the existing suite of checked cast instructions with:
- unconditional_checked_cast, which performs an unconditional cast that aborts on failure (like the former downcast unconditional); and
- checked_cast_br, which performs a conditional pass and branches on whether the cast succeeds, passing the result to the true branch as an argument.
Both instructions take a CheckedCastKind that discriminates the different casting modes formerly discriminated by instruction type. This eliminates a source of null references in SIL and eliminates null SIL addresses completely.
Swift SVN r8696
The current implementation of dealloc_stack in IR-gen is a
no-op, but that's very much wrong for types with non-trivial
local allocation requirements, e.g. archetypes. So we need
to be able to do non-trivial code here. However, that means
modeling both the buffer pointer and the allocated address
in SIL.
To make this more type-safe, introduce a SIL-specific
'[local_storage] T' type that represents the required
allocation for locally storing a T. alloc_stack now returns
one of those in additon to a *T, and dealloc_stack expects
the former.
IR-gen still implements dealloc_stack as a no-op, but
that's now easy to fix.
Swift SVN r6937
a lot closer to successfully emitting the polymorphic-min-over-ranges
example; the main blocker right now seems to be that the witness
for a static member function is not, in fact, a static member
function at al, but a freestanding function. That's legitimate,
but it probably needs some shepherding through the witness
system.
Swift SVN r2532
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
