Redesign code layout

[lausek]

Current

The current Module looks like this:

• CodeObject main
  • globals
  • locals
  • consts
  • code
• CodeObject add
  • globals
  • locals
  • consts
  • code
• ...

New Layout

• idents: globals + locals
• consts
• entries: HashMap<Variable, usize> mapping the function name to the offset inside code
• code which is the concatenated list of bytecode instructions from main and add

main:
    ...
    ret
add:
    ...
    ret

Pros

• Size of Module is expected to decrease by a lot
  • CodeObject can reuse identifiers and constants
• The new layout is way simpler than the previous one

Steps for redesign

• remove current struct Module
• redefine CodeObject according to new layout
  • wait until #6 is resolved
  • refactor ModuleProtocol trait -> remove slot method
  • implement ModuleProtocol
• create new type CodeObjectFunction wip name
  • tuple containing a reference to the CodeObject and an offset
  • implement CallProtocol

[lausek]

If we define the ENTRY_POINT to be always at offset 0, resolution of a programs starting point will become way simpler. Modules without an entry point will have a ret as first instruction.

[lausek]

implemented by #7