Numerous changes, including:
* Changed the way variables and instructions are handled in basic blocks to
be more efficient.
* Eliminated SExprRef.
* Simplified futures.
* Fixed documentation.
* Compute dominator and post dominator trees.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@217556 91177308-0d34-0410-b5e6-96231b3b80d8
til::SExpr. This is a large patch, with many small changes to pretty printing
and expression lowering to make the new SExpr representation equivalent in
functionality to the old.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214089 91177308-0d34-0410-b5e6-96231b3b80d8