[heap] Move RecordSlot to concurrent marking

Move Slot recording to concurrent and incremental marking phase and
out of the atomic pause. Records more slots to remove
slot recording completely from the pause.

Bug: chromium:844008
Change-Id: I13ba20b4839990134dc37bd909fb0a2d66e13c64
Reviewed-on: https://chromium-review.googlesource.com/1104348
Commit-Queue: Dominik Inführ <dinfuehr@google.com>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53804}

src/heap/concurrent-marking.cc

@@ -362,12 +362,24 @@ class ConcurrentMarkingVisitor final
     weak_objects_->ephemeron_hash_tables.Push(task_id_, table);
 
     for (int i = 0; i < table->Capacity(); i++) {
+      Object** key_slot =
+          table->RawFieldOfElementAt(EphemeronHashTable::EntryToIndex(i));
       HeapObject* key = HeapObject::cast(table->KeyAt(i));
+      MarkCompactCollector::RecordSlot(table, key_slot, key);
+
+      Object** value_slot =
+          table->RawFieldOfElementAt(EphemeronHashTable::EntryToValueIndex(i));
 
       if (marking_state_.IsBlackOrGrey(key)) {
-        Object** value_slot = table->RawFieldOfElementAt(
-            EphemeronHashTable::EntryToValueIndex(i));
         VisitPointer(table, value_slot);
+
+      } else {
+        Object* value = table->ValueAt(i);
+
+        if (value->IsHeapObject()) {
+          MarkCompactCollector::RecordSlot(table, value_slot,
+                                           HeapObject::cast(value));
+        }
       }
     }
 

src/heap/mark-compact-inl.h

@@ -93,11 +93,23 @@ int MarkingVisitor<fixed_array_mode, retaining_path_mode, MarkingState>::
   collector_->AddEphemeronHashTable(table);
 
   for (int i = 0; i < table->Capacity(); i++) {
+    Object** key_slot =
+        table->RawFieldOfElementAt(EphemeronHashTable::EntryToIndex(i));
     HeapObject* key = HeapObject::cast(table->KeyAt(i));
+    collector_->RecordSlot(table, key_slot, key);
+
+    Object** value_slot =
+        table->RawFieldOfElementAt(EphemeronHashTable::EntryToValueIndex(i));
+
     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()) {
+        collector_->RecordSlot(table, value_slot, HeapObject::cast(value));
+      }
     }
   }
 

src/heap/mark-compact.cc

@@ -1910,16 +1910,10 @@ class EphemeronHashTableMarkingTask : public ItemParallelJob::Task {
       for (int i = start; i < limit; i++) {
         HeapObject* key = HeapObject::cast(table->KeyAt(i));
         if (collector_->marking_state()->IsBlackOrGrey(key)) {
-          Object** key_slot =
-              table->RawFieldOfElementAt(EphemeronHashTable::EntryToIndex(i));
-          collector_->RecordSlot(table, key_slot, key);
-          Object** value_slot = table->RawFieldOfElementAt(
-              EphemeronHashTable::EntryToValueIndex(i));
-          Object* value_obj = *value_slot;
+          Object* value_obj = table->ValueAt(i);
 
           if (value_obj->IsHeapObject()) {
             HeapObject* value = HeapObject::cast(value_obj);
-            collector_->RecordSlot(table, value_slot, value);
 
             if (collector_->marking_state()->WhiteToGrey(value)) {
               worklist_->Push(task_id_, value);