Efficient method router that supports multiple simultaneous object versions

280 <

class signature for super class at class-level ^

offset into object for instance variables of class-level 0

-282
-283
-284

method table pointer for class-level 1

class signature for super class at class-level 1

offset into object for instance variables of class-level 1

method table pointer for class-level 2

class signature for super class at class-level 2

offset into object for instance variables of class-level 2

method table pointer for class-level X

class signature for super class at class-level X

offset into object for instance variables of class-level X

FIG. 2B