Hi, Please review this implementation for the RFE to enable escape analysis when debugging.
Bug: https://bugs.openjdk.java.net/browse/JDK-8227745 Webrev: http://cr.openjdk.java.net/~rrich/webrevs/2019/8227745/webrev.0/ In short the JVMTI implementation is changed to revert EA based optimizations just before objects escape through JVMTI. At runtime there is no escape information for each object in scope. Instead each scope is annotated, if non-escaping objects exist and if some are passed as parameters. If a JVMTI agent accesses a reference on stack, then the owning compiled frame C is deoptimized, if any non-escaping object is in scope. Scalar replaced objects are reallocated on the heap and objects with eliminated locking are relocked. This is called "deoptimizing objects" for short. If the agent accesses a reference in a callee frame of C and C is passing any non-escaping object as argument then C and its objects are deoptimized as well. Deoptimized objects are kept as deferred updates (preexisting JavaThread::_deferred_locals_updates). Either all objects of a compiled frame are deoptimized or none. It is annotated at the corresponding deferred updates if it happened already in order to avoid doing it twice. There is preexisting code to deoptimize objects when deoptimizing a compiled frame. The code was extended to be able to deoptimize objects of a frame that is not the top frame and to let another thread than the owning thread do it. Thanks, Richard.
