Definition of __weak_reference that preserves weak
symbols in llvm IR
Fix stringification of collections of functions
Better handling of GEPs - now fixed-point computation
propagates back to the aggregate
Prune implausible FP targets
Add support for rewinding geps to call instructions.
Note, as we don't have time to do this properly,
we currently hardcode the specific cases
Add support for weak-reference functions in callgraph analysis