Summary:
LLVM and llair have similar memory models, and we don't want to
duplicate any definitions or theorems. This adds a new memory model
theory which should be understandable in its own right. A heap is a
mapping from addresses to bytes, alongside a set of valid addresses, and
intervals that have been allocated already. Primitives are defined for
allocating and de-allocating as well as reading and writing chuncks of
bytes.
There is also a generic type of structured values, and functions for
converting them to/from byte arrays.
Reviewed By: jberdine
Differential Revision: D17074470
fbshipit-source-id: bdab6089f