[heap] Record slots in atomic pause

Bug: chromium:851877
Change-Id: Ib3b4ec7086ecf2115e42a30fab10be1ae6b67593
Reviewed-on: https://chromium-review.googlesource.com/1096943Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@google.com>
Cr-Commit-Position: refs/heads/master@{#53663}

src/heap/concurrent-marking.cc

@@ -364,22 +364,10 @@ class ConcurrentMarkingVisitor final
     for (int i = 0; i < table->Capacity(); i++) {
       HeapObject* key = HeapObject::cast(table->KeyAt(i));
 
-      Object** key_slot =
-          table->RawFieldOfElementAt(EphemeronHashTable::EntryToIndex(i));
-      Object** value_slot =
-          table->RawFieldOfElementAt(EphemeronHashTable::EntryToValueIndex(i));
-
-      MarkCompactCollector::RecordSlot(table, key_slot, key);
-
       if (marking_state_.IsBlackOrGrey(key)) {
+        Object** value_slot = table->RawFieldOfElementAt(
+            EphemeronHashTable::EntryToValueIndex(i));
         VisitPointer(table, value_slot);
-      } else {
-        Object* value = *value_slot;
-
-        if (value->IsHeapObject()) {
-          MarkCompactCollector::RecordSlot(table, value_slot,
-                                           HeapObject::cast(value));
-        }
       }
     }
 

src/heap/mark-compact.cc

@@ -1861,6 +1861,9 @@ void MarkCompactCollector::ProcessWeakCollections() {
     for (int i = 0; i < table->Capacity(); i++) {
       HeapObject* heap_object = HeapObject::cast(table->KeyAt(i));
       if (non_atomic_marking_state()->IsBlackOrGrey(heap_object)) {
+        Object** key_slot =
+            table->RawFieldOfElementAt(EphemeronHashTable::EntryToIndex(i));
+        RecordSlot(table, key_slot, heap_object);
         Object** value_slot = table->RawFieldOfElementAt(
             EphemeronHashTable::EntryToValueIndex(i));
         if (V8_UNLIKELY(FLAG_track_retaining_path) &&