Hi all, this patch fixes an issue where an oop in JvmtiBreakpoint, JvmtiBreakpoint::_class_loader, was found by the unhandled oop detector.
Instead of registering the oop as an unhandled oop, which would have worked, I decided to wrap the oop in a handle as long as it is on the stack. A JvmtiBreakpoint is created on the stack by the two methods JvmtiEnv::SetBreakpoint and JvmtiEnv::ClearBreakpoint. This JvmtiBreakpoint is only created to carry the Method*, jlocation and oop to a VM operation, VM_ChangeBreakpoints. VM_ChangeBreakpoints will, when at a safepoint, allocate a new JvmtiBreakpoint on the native heap, copy the values from the stack allocated JvmtiBreakpoint and then place/clear the newly alloacted JvmtiBreakpoint in JvmtiCurrentBreakpoints::_jvmti_breakpoints. I have updated to the code to check that the public constructor is only used to allocate JvmtiBreakpoints on the stack (to warn a future programmer if he/she decides to allocate one on the heap). The class_loader oop is now wrapped in a Handle for stack allocated JvmtiBreakpoints. Due to the stack allocated JvmtiBreakpoint having the oop in a handle, the oops_do method of VM_ChangeBreakpoints can be removed. This also makes the oop in the handle safe for use after the VM_ChangeBreakpoint operation is finished. The unhandled oop in the JvmtiBreakpoint allocated on the heap will be visited by the GC via jvmtiExport::oops_do -> JvmtiCurrentBreakpoints::oops_do -> JvmtiBreakpoints::oops_do -> GrowableCache::oops_do -> JvmtiBreakpoint::oops_do, since it is being added to. I've also removed some dead code to simplify the change: - GrowableCache::insert - JvmtiBreakpoint::copy - JvmtiBreakpoint::lessThan - GrowableElement::lessThan Finally, I also formatted JvmtiEnv::ClearBreakpoint and Jvmti::SetBreakpoint exactly the same to highlight that they share all code except one line. Unfortunately, I was not able to remove this code duplication in a good way. Webrev: http://cr.openjdk.java.net/~ehelin/8025834/webrev.00/ Testing: - JPRT - The four tests that were failing are now passing Thanks, Erik
