Crusade against string lookup

[karkhaz]

We have plenty of this sort of thing:

for(extremely_tight_performance_critical_loop)
{
  unsigned max_depth=options.get_unsigned_int_option("depth");
}

depth doesn't ever change, there's no need to look it up in a table every time we do a symex step. I recommend that we find these things, and replace them with

class symext
{
public:
  symext(const optionst &options)
  : depth(options.get_unsigned_int_option("depth"))
  {
  }
protected:
  const unsigned depth;
}

even if the option isn't constant, we can still have it as a member variable (although options that change through the life of the program are somewhat questionable...). Having a member variable means we don't do table lookups, and having the member const additionally means that the branch predictor has a happier time (for boolean members).