As an alternative to using hmethod address, this correctioni pairs in the vtable entries of a language withmultiple inheritance, we could leave the entries as simple pointers, but make them point to code that updates this in-line, and then jumps to the beginning of the appropriate method, much as Java 8 and Scala do to implement default methods on a standard Java virtual machine. Show the sequence of instructions executed under this scheme. What factors will influence whether it runs faster or slower than the sequence shown in Example C 10.60? Which scheme will use less space? (Remember to count both code and data structure size, and consider which instructions must be replicated at every call site.)

Pursuing the replacement of data structures with executable code even further, consider an implementation in which the vtable itself consists of executable code. Show what this code would look like and, again, discuss the implications for time and space overhead.