Move bits mask from Metadata.h to SwiftShims's HeapObject.h. This
exposes the bit masks to the stdlib, so that the stdlib doesn't have
to have its own magic numbers per-platform. This also enhances
readability for BridgeObject, whose magic numbers are mostly derived
from Swift's ABI.
I had optimistically written the code here optimistically hoping #7837 would land in time for me to merge, but that didn't happen, so adjust some things to match the current 12-byte object header size on 32-bit, and introduce some ABI constants for the expected 32- and 64-bit object header sizes we can assert against so that we have some robustness when it eventually changes again. Implements rdar://problem/31768303.
- Add RuntimeTarget template This will allow for converting between
metadata structures for native host and remote target architectures.
- Create InProcess and External templates for stored pointers
Add a few more types to abstract pointer access in the runtime
structures but keep native in-process pointer access the same as that
with a plain old pointer type.
There is now a notion of a "stored pointer", which is just the raw value
of the pointer, and the actual pointer type, which is used for loads.
Decoupling these allows us to fork the behavior when looking at metadata
in an external process, but keep things the same for the in-process
case.
There are two basic "runtime targets" that you can use to work with
metadata:
InProcess: Defines the pointer to be trivially a T* and stored as a
uintptr_t. A Metadata * is exactly as it was before, but defined via
AbstractMetadata<InProcess>.
External: A template that requires a target to specify its pointer size.
ExternalPointer: An opaque pointer in another address space that can't
(and shouldn't) be indirected with operator* or operator->. The memory
reader will fetch the data explicitly.
The standard library has grown significantly, and we need a new
directory structure that clearly reflects the role of the APIs, and
allows future growth.
See stdlib/{public,internal,private}/README.txt for more information.
Swift SVN r25876
