Started partitioning of transfer function logic (and thus the policy behind 
these operations) into GRTransferFuncs and its subclasses.  Originally all
of this logic was handled by the class RValue, but in reality different
analyses will want more flexibility on how they evaluate different values.

Transfer functions migrated so far: "Cast"


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@47125 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed