8286814: Shenandoah: RedefineRunningMethods.java test failed with Loom

Reviewed-by: shade

Author: zhengyu123

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

@@ -2308,10 +2308,20 @@ void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
 }
 
 bool ShenandoahHeap::requires_barriers(stackChunkOop obj) const {
-  ShenandoahHeapRegion* region = heap_region_containing(obj);
-  bool allocated_after_mark_start = marking_context()->allocated_after_mark_start(obj);
-  bool requires_concmark_barriers = is_concurrent_mark_in_progress() && !allocated_after_mark_start;
-  bool requires_loadref_barriers = has_forwarded_objects() && cast_from_oop<HeapWord*>(obj) < heap_region_containing(obj)->get_update_watermark();
-  bool requires_deep_loadref_barriers = allocated_after_mark_start && has_forwarded_objects();
-  return requires_concmark_barriers || requires_loadref_barriers || requires_deep_loadref_barriers;
+  if (is_idle()) return false;
+
+  // Objects allocated after marking start are implicitly alive, don't need any barriers during
+  // marking phase.
+  if (is_concurrent_mark_in_progress() && marking_context()->allocated_after_mark_start(obj)) {
+    return false;
+  }
+
+  // Objects allocated after evacuation start are guaranteed in to-space, don't need any barriers
+  // during evacuation/update references phases.
+  if (has_forwarded_objects() &&
+      cast_from_oop<HeapWord*>(obj) >= heap_region_containing(obj)->get_update_watermark()) {
+    return false;
+  }
+
+  return true;
 }

src/hotspot/share/runtime/continuationFreezeThaw.cpp

@@ -1285,8 +1285,8 @@ stackChunkOop Freeze<ConfigT>::allocate_chunk(size_t stack_size) {
   if (fast_oop != nullptr) {
     assert(!chunk->requires_barriers(), "Unfamiliar GC requires barriers on TLAB allocation");
   } else {
-    assert(!UseZGC || !chunk->requires_barriers(), "Allocated ZGC object requires barriers");
-    _barriers = !UseZGC && chunk->requires_barriers();
+    assert(!UseZGC || !UseShenandoahGC || !chunk->requires_barriers(), "Allocated ZGC/ShenandoahGC object requires barriers");
+    _barriers = !UseZGC && !UseShenandoahGC && chunk->requires_barriers();
 
     if (_barriers) {
       log_develop_trace(continuations)("allocation requires barriers");