swift234

several improvements to CFG printer.
Finish implementing the basics of AllocVarInst
Stub out support for (initialized) NamedPatterns.

We now compile:

func named_pattern() -> Int {
  var local_var : Int = 4
  return local_var
}

Into:

bb0:	 ; Preds:
  %0 = alloc_var local_var, type=[byref(heap)] Int
*  %1 = constantref convertFromIntegerLiteral, type=metatype<Int64> -> (val : Builtin.Int64) -> Int
*  %2 = typeof metatype<Int64>
*  %3 = apply %1(%2)
*  %4 = integerliteral 4, width=64
*  %5 = apply %3(%4)
  %6 = store %5 -> %0 [initialization]
  %7 = varref local_var, type=Int
  %8 = load %7
  %9 = return (%8)

... where the *'d instructions are all the nonsense currently used to generate "4" as a value.  

The alloc_var and store feel right to me, but varref now needs to go away, and the zero initialized case is still missing.



Swift SVN r2969