RFA: Changes to interpreter to avoid non-debugging slowdown

[Tom Tromey]

>>>>> "Kyle" == Kyle Galloway <kgallowa@redhat.com> writes:

Tom> We talked about it offline and the idea is, we need to track the types
Tom> of stack and local variable slots while interpreting if the debugging
Tom> code is enabled.  However, we don't want to do this unconditionally as
Tom> it adds overhead to interpretation.

So, I looked at JVMTI a little more.  It seems that we only need to
know the types of locals, is that correct?

I'm wondering now if it is worthwhile to make an entire second
interpreter just for this.  Perhaps an extra store in the various
'store' instructions is not too much overhead.

Are there other reasons we may want a special debug-only interpreter?
I thought Keith said there were, but I don't recall why exactly...


That said, your updated patch is looking pretty good to me.
One more addition I didn't think of yesterday: you have to update
stacktrace.cc to account for the new interpreter.

Tom