The JVM also doesn't (I'm fairly sure) have an indirect JMP instruction, which means you can't compile a polymorphic source-language method call into a JMP inside of a single generated method. Instead you have to use a call to a method. That means that tail-calls to functions passed as parameters (rather than functions that can be statically bound at compile time) can't use JMP.
I'm talking about the bytecode instructions standardized in the "JVM" specification. The "JVM" has to implement the semantics of the instructions found in your bytecode program, or your program won't run. Your bytecode program can only use bytecodes defined in the "JVM" specification, or it won't run on the "JVM".
Because the security manager needs to be able to introspect the stack. Avian isn't a JVM; it's "designed to provide a useful subset of Java's features" and can run some Java code.
It's actually possible to implement the stack inspection in a tail-call-friendly way (along the lines of Racket's continuation marks IIRC), though AFAIK nobody does it.
> Because the security manager needs to be able to introspect the stack.
Not allowing certain “optimizations” in security-sensitive contexts is perfectly fine. In fact, this is exactly what Avian, the CLR (and pretty much everyone else) is doing.
> Avian isn't a JVM; it's "designed to provide a useful subset of Java's features" and can run some Java code.
Now you're talking about legal aspects. Frankly, I'm not interested in discussing those.
Avian is a JVM for all practical purposes. If you disagree, please provide a test-case which runs on HotSpot but not on Avian.
