These two value types represent the state of CPU flags after an integer
comparison and a floating point comparison respectively.
Instructions using these types TBD.
- Create a new kind of stack slot: emergency_slot.
- Add a get_emergency_slot() method which finds a suitable emergency
slot given a list of slots already in use.
- Use emergency spill slots when schedule_moves needs them.
Add a StackSlotKind enumeration to help keep track of the different
kinds of stack slots supported:
- Incoming and outgoing function arguments on the stack.
- Spill slots and locals.
Change the text format syntax for declaring a stack slot to use a kind
keyword rather than just 'stack_slot'.
All values are now references into the value table, so drop the
distinction between direct and table values. Direct values don't exist
any more.
Also remove the parser support for the 'vxNN' syntax. Only 'vNN' values
can be parsed now.
