Getting class names from precompiled Ruby byte code with RubyVM::InstructionSequence

instruction_sequence_classes.rb

      queued_classes = []
      queued_classes << [@instructions.to_a[13].select! {|item| item.is_a? Array }]
      while true
        iterations += 1
        instructions, super_class, parent_class = queued_classes.shift
        break unless instructions
        if instructions[0] == :defineclass
          next if instructions[1] == :singletonclass
          class_name = parent_class ? :"#{parent_class}::#{instructions[1]}" : instructions[1]
          class_info = instructions[2]
          info = ClassInfo.new(class_info[5][/\<([^:]+)/, 1], class_name, super_class)
          class_instructions = class_info[13]
          @classes << info
          parent_class = parent_class ? "#{parent_class}::#{class_name}" : class_name
          i = 0
          class_instructions.each do |instruction|
            next unless instruction.is_a? Array
            super_class = nil
            if instruction[0] == :defineclass
              index = i - 2
              while index > 1
                inst = class_instructions[index]
                break unless inst[0] == :getconstant
                if super_class
                  super_class = "#{inst[1]}::#{super_class}"
                else
                  super_class = inst[1].to_s
                end
                index -= 1
              end
            end
            queued_classes << [instruction, super_class, parent_class]
            i += 1
          end
        else
          i = 0
          instructions.each do |instruction|
            next unless instruction.is_a? Array
            super_class = nil
            name = instruction[0]
            if name == :defineclass
              index = i - 2
              while index > 1
                inst = instructions[index]
                break unless inst[0] == :getconstant
                if super_class
                  super_class = "#{inst[1]}::#{super_class}"
                else
                  super_class = inst[1].to_s
                end
                index -= 1
              end
            end
            queued_classes << [instruction, super_class, parent_class]
            i += 1
          end
        end
      end