8370726: GenShen: Misplaced assertion that old referent is marked during young collection

Reviewed-by: xpeng, ysr

src/hotspot/share/gc/shenandoah/shenandoahGeneration.cpp

@@ -800,7 +800,7 @@ ShenandoahGeneration::ShenandoahGeneration(ShenandoahGenerationType type,
                                            size_t max_capacity) :
   _type(type),
   _task_queues(new ShenandoahObjToScanQueueSet(max_workers)),
-  _ref_processor(new ShenandoahReferenceProcessor(MAX2(max_workers, 1U))),
+  _ref_processor(new ShenandoahReferenceProcessor(this, MAX2(max_workers, 1U))),
   _affiliated_region_count(0), _humongous_waste(0), _evacuation_reserve(0),
   _used(0), _bytes_allocated_since_gc_start(0),
   _max_capacity(max_capacity),

src/hotspot/share/gc/shenandoah/shenandoahReferenceProcessor.cpp

@@ -223,13 +223,13 @@ void ShenandoahRefProcThreadLocal::set_discovered_list_head<oop>(oop head) {
 
 AlwaysClearPolicy ShenandoahReferenceProcessor::_always_clear_policy;
 
-ShenandoahReferenceProcessor::ShenandoahReferenceProcessor(uint max_workers) :
+ShenandoahReferenceProcessor::ShenandoahReferenceProcessor(ShenandoahGeneration* generation, uint max_workers) :
   _soft_reference_policy(&_always_clear_policy),
   _ref_proc_thread_locals(NEW_C_HEAP_ARRAY(ShenandoahRefProcThreadLocal, max_workers, mtGC)),
   _pending_list(nullptr),
   _pending_list_tail(&_pending_list),
   _iterate_discovered_list_id(0U),
-  _stats() {
+  _generation(generation) {
   for (size_t i = 0; i < max_workers; i++) {
     _ref_proc_thread_locals[i].reset();
   }
@@ -311,7 +311,7 @@ bool ShenandoahReferenceProcessor::should_discover(oop reference, ReferenceType
     return false;
   }
 
-  if (!heap->is_in_active_generation(referent)) {
+  if (!_generation->contains(referent)) {
     log_trace(gc,ref)("Referent outside of active generation: " PTR_FORMAT, p2i(referent));
     return false;
   }
@@ -329,31 +329,23 @@ bool ShenandoahReferenceProcessor::should_drop(oop reference, ReferenceType type
     return true;
   }
 
-  shenandoah_assert_mark_complete(raw_referent);
-  ShenandoahHeap* heap = ShenandoahHeap::heap();
   // Check if the referent is still alive, in which case we should drop the reference.
   if (type == REF_PHANTOM) {
-    return heap->marking_context()->is_marked(raw_referent);
+    return _generation->complete_marking_context()->is_marked(raw_referent);
   } else {
-    return heap->marking_context()->is_marked_strong(raw_referent);
+    return _generation->complete_marking_context()->is_marked_strong(raw_referent);
   }
 }
 
 template <typename T>
 void ShenandoahReferenceProcessor::make_inactive(oop reference, ReferenceType type) const {
   if (type == REF_FINAL) {
-#ifdef ASSERT
-    auto referent = reference_referent_raw<T>(reference);
-    auto heap = ShenandoahHeap::heap();
-    shenandoah_assert_mark_complete(referent);
-    assert(reference_next<T>(reference) == nullptr, "Already inactive");
-    assert(heap->marking_context()->is_marked(referent), "only make inactive final refs with alive referents");
-#endif
-
     // Don't clear referent. It is needed by the Finalizer thread to make the call
     // to finalize(). A FinalReference is instead made inactive by self-looping the
     // next field. An application can't call FinalReference.enqueue(), so there is
     // no race to worry about when setting the next field.
+    assert(reference_next<T>(reference) == nullptr, "Already inactive");
+    assert(_generation->complete_marking_context()->is_marked(reference_referent_raw<T>(reference)), "only make inactive final refs with alive referents");
     reference_set_next(reference, reference);
   } else {
     // Clear referent
@@ -443,12 +435,8 @@ oop ShenandoahReferenceProcessor::drop(oop reference, ReferenceType type) {
   HeapWord* raw_referent = reference_referent_raw<T>(reference);
 
 #ifdef ASSERT
-  if (raw_referent != nullptr) {
-    ShenandoahHeap* heap = ShenandoahHeap::heap();
-    ShenandoahHeapRegion* region  = heap->heap_region_containing(raw_referent);
-    ShenandoahMarkingContext* ctx = heap->generation_for(region->affiliation())->complete_marking_context();
-    assert(ctx->is_marked(raw_referent), "only drop references with alive referents");
-  }
+  assert(raw_referent == nullptr || _generation->complete_marking_context()->is_marked(raw_referent),
+         "only drop references with alive referents");
 #endif
 
   // Unlink and return next in list

src/hotspot/share/gc/shenandoah/shenandoahReferenceProcessor.hpp

@@ -140,6 +140,8 @@ private:
 
   ReferenceProcessorStats _stats;
 
+  ShenandoahGeneration* _generation;
+
   template <typename T>
   bool is_inactive(oop reference, oop referent, ReferenceType type) const;
   bool is_strongly_live(oop referent) const;
@@ -172,7 +174,7 @@ private:
   void clean_discovered_list(T* list);
 
 public:
-  ShenandoahReferenceProcessor(uint max_workers);
+  ShenandoahReferenceProcessor(ShenandoahGeneration* generation, uint max_workers);
 
   void reset_thread_locals();
   void set_mark_closure(uint worker_id, ShenandoahMarkRefsSuperClosure* mark_closure);