interface dispatch

Sat Oct 23 17:29:00 GMT 1999

>> > On another note regarding the size of the ioffset tables, how would you 
> > deal with
> > 	invokeinterface	InterfaceMethodRef(InterfaceType, "equals")
> > instructions?
> > 
> > If you adopted the assumption that java.lang.Object is an interface
>> Why? Object is a class. My assumption was that class inheritance
> and virtual calls would be handled using a simpler and faster scheme
> than what you use for interfaces.

It may be trivial, but I just wanted to point out that you have to
recognize that case in your compiler in order to identify cases where
you can synthesize a virtual call out of an invokeinterface instruction.
It won't work to blindly apply the interface dispatch scheme whenever you
see an invokeinterface instruction in the bytecode.
In an earlier discussion, I pointed out that the correct way to compile
interface A {}
f(A x) {
	x.equals(...)
}
is by using "invokeinterface" as opposed to "invokevirtual", and that the
correct run-time semantics is
	checkcast A
	invokevirtual "equals"
Basically, all I meant to say is that the compiler needs to identify
such instances of invokeinterface to which the faster scheme can be 
applied.
	- Godmar