* Must update PHI node to have a pair between predecessor and value.
* Enhance BB to make predecessor handling easier (to update PHI nodes)
* Must add BB iterator to iterate depth first, and reverse depth first
* Move getBinaryOperator from Instruction to BinaryOperator
* Provide a pass that eliminates critical edges from the CFG
* Provide a print hook to print out xvcg format files for vis
* I need to provide an option to the bytecode loader to ignore memory 
  dependance edges.  Instead, the VM would just treat memory operations 
  (load, store, getfield, putfield, call) as pinned instructions.
* I need to have a way to prevent taking the address of a constant pool
  reference.  You should only be able to take the address of a variable.
  Maybe taking the address of a constant copies it?  What about virtual 
  function tables?  Maybe a const pointer would be better...
* Structures should be accessed something like this: ubyte is ok.  Limits 
  structure size to 256 members.  This can be fixed later by either: 
    1. adding varient that takes ushort
    2. Splitting structures into nested structures each of half size
  <float> %f = loadfield *{int, {float}} Str, ubyte 1, ubyte 0
  storefield float %f, *{int, {float}} Str, ubyte 1, ubyte 0
* I'm noticing me writing a lot of code that looks like this (dtor material here):
  ConstPool.dropAllReferences();
  ConstPool.delete_all();
  ConstPool.setParent(0);
  ~ConstPool

* Need a way to attach bytecode block info at various levels of asm code.
* Rename "ConstantPool" to "ConstPool"
* Maybe ConstantPool objects should keep themselves sorted as things are 
  inserted.
* Need to be able to inflate recursive types.  %x = { *%x }, %x = %x ()
* Recognize and save comments in assembly and bytecode format
* Encode line number table in bytecode (like #line), optional table

* Encode negative relative offsets in the bytecode file

* Implement switch to switch on a constant pool array of type: 
  [{ label, int }] or [label]   (lookup vs index switch)
* Apparently bison has a %pure_parser option.  Maybe useful for Assembly/Parser

* Implement a header file that can read either assembly or bytecode, implement 
  a writer that can output either based on what is read with this reader..
* Implement the following derived types:
  * structure/record               { int %foo, int %bar} or { %foo = int, int }
  * pointer                          int *
  * "packed format", like this:    [4 x sbyte]: Packed SIMD datatype
* Maybe 'tailcall' also?
* It might be nice to support enumerations of some sort... especially for use
  as a compiler IR
* Include a method level bytecode block that defines a mapping between values 
  and registers that defines a minimally register allocated code.  This can
  make me finally address how to encode extensions in assembly.
* Bytecode reader should use extensions that may or may not be linked into the
  application to read blocks.  Thus an easy way to ignore symbol table info
  would be to not link in that reader into the app.