5251   verify_work_stacks_empty();
5252 
5253   {
5254     GCTraceTime(Debug, gc, phases) t("Weak Processing", _gc_timer_cm);
5255     WeakProcessor::weak_oops_do(&_is_alive_closure, &do_nothing_cl);
5256   }
5257 
5258   if (should_unload_classes()) {
5259     {
5260       GCTraceTime(Debug, gc, phases) t("Class Unloading", _gc_timer_cm);
5261 
5262       // Unload classes and purge the SystemDictionary.
5263       bool purged_class = SystemDictionary::do_unloading(_gc_timer_cm);
5264 
5265       // Unload nmethods.
5266       CodeCache::do_unloading(&_is_alive_closure, purged_class);
5267 
5268       // Prune dead klasses from subklass/sibling/implementor lists.
5269       Klass::clean_weak_klass_links(purged_class);
5270 
5271 #if INCLUDE_JVMCI
5272       // Clean JVMCI metadata handles.
5273       JVMCI::do_unloading(&_is_alive_closure, purged_class);
5274 #endif
5275     }
5276   }
5277 
5278   // Restore any preserved marks as a result of mark stack or
5279   // work queue overflow
5280   restore_preserved_marks_if_any();  // done single-threaded for now
5281 
5282   rp->set_enqueuing_is_done(true);
5283   rp->verify_no_references_recorded();
5284 }
5285 
5286 #ifndef PRODUCT
5287 void CMSCollector::check_correct_thread_executing() {
5288   Thread* t = Thread::current();
5289   // Only the VM thread or the CMS thread should be here.
5290   assert(t->is_ConcurrentGC_thread() || t->is_VM_thread(),
5291          "Unexpected thread type");
5292   // If this is the vm thread, the foreground process
5293   // should not be waiting.  Note that _foregroundGCIsActive is
5294   // true while the foreground collector is waiting.

5251   verify_work_stacks_empty();
5252 
5253   {
5254     GCTraceTime(Debug, gc, phases) t("Weak Processing", _gc_timer_cm);
5255     WeakProcessor::weak_oops_do(&_is_alive_closure, &do_nothing_cl);
5256   }
5257 
5258   if (should_unload_classes()) {
5259     {
5260       GCTraceTime(Debug, gc, phases) t("Class Unloading", _gc_timer_cm);
5261 
5262       // Unload classes and purge the SystemDictionary.
5263       bool purged_class = SystemDictionary::do_unloading(_gc_timer_cm);
5264 
5265       // Unload nmethods.
5266       CodeCache::do_unloading(&_is_alive_closure, purged_class);
5267 
5268       // Prune dead klasses from subklass/sibling/implementor lists.
5269       Klass::clean_weak_klass_links(purged_class);
5270 

5271       // Clean JVMCI metadata handles.
5272       JVMCI_ONLY(JVMCI::do_unloading(&_is_alive_closure, purged_class));

5273     }
5274   }
5275 
5276   // Restore any preserved marks as a result of mark stack or
5277   // work queue overflow
5278   restore_preserved_marks_if_any();  // done single-threaded for now
5279 
5280   rp->set_enqueuing_is_done(true);
5281   rp->verify_no_references_recorded();
5282 }
5283 
5284 #ifndef PRODUCT
5285 void CMSCollector::check_correct_thread_executing() {
5286   Thread* t = Thread::current();
5287   // Only the VM thread or the CMS thread should be here.
5288   assert(t->is_ConcurrentGC_thread() || t->is_VM_thread(),
5289          "Unexpected thread type");
5290   // If this is the vm thread, the foreground process
5291   // should not be waiting.  Note that _foregroundGCIsActive is
5292   // true while the foreground collector is waiting.