Merging ContentArray into DescriptorArray

src/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1849 matching lines @@
     base_marker()->MarkObjectAndPush(reinterpret_cast<HeapObject*>(obj));
   }
 }
 
 
 template <class T>
 void Marker<T>::MarkDescriptorArray(DescriptorArray* descriptors) {
   // Empty descriptor array is marked as a root before any maps are marked.
   ASSERT(descriptors != descriptors->GetHeap()->empty_descriptor_array());
 
-  // The DescriptorArray contains a pointer to its contents array, but the
-  // contents array will be marked black and hence not be visited again.
-  if (!base_marker()->MarkObjectAndPush(descriptors)) return;
-  FixedArray* contents = FixedArray::cast(
-      descriptors->get(DescriptorArray::kContentArrayIndex));
-  ASSERT(Marking::IsWhite(Marking::MarkBitFrom(contents)));
-  base_marker()->MarkObjectWithoutPush(contents);
+  if (!base_marker()->MarkObjectWithoutPush(descriptors)) return;
+  Object** descriptor_start = descriptors->data_start();
+
+  if (descriptors->HasEnumCache()) {

[Michael Starzinger, 2012/06/01 14:03:15]

It's important that we don't forget to mark every object that could be
referenced from the header. So a comment about this block explaining that might
be a good idea.

[Toon Verwaest, 2012/06/04 07:30:45]

Done.

+    Object** enum_cache_slot = descriptors->GetEnumCacheSlot();
+    Object* enum_cache = *enum_cache_slot;
+    base_marker()->MarkObjectAndPush(
+        reinterpret_cast<HeapObject*>(enum_cache));
+    mark_compact_collector()->RecordSlot(descriptor_start,
+                                         enum_cache_slot,
+                                         enum_cache);
+  }
 
   // If the descriptor contains a transition (value is a Map), we don't mark the
   // value as live. It might be set to the NULL_DESCRIPTOR in
   // ClearNonLiveTransitions later.
   for (int i = 0; i < descriptors->number_of_descriptors(); ++i) {
+    Object** key_slot = descriptors->GetKeySlot(i);
+    Object* key = *key_slot;
+    if (key->IsHeapObject()) {
+      base_marker()->MarkObjectAndPush(reinterpret_cast<HeapObject*>(key));
+      mark_compact_collector()->RecordSlot(descriptor_start, key_slot, key);
+    }
+
+    Object** value_slot = descriptors->GetValueSlot(i);
+    if (!(*value_slot)->IsHeapObject()) continue;
+    HeapObject* value = HeapObject::cast(*value_slot);
+
+    mark_compact_collector()->RecordSlot(descriptor_start,
+                                         value_slot,
+                                         *value_slot);

[Michael Starzinger, 2012/06/01 14:03:15]

Just pass "value" as the third parameter here.

[Toon Verwaest, 2012/06/04 07:30:45]

Done.

+
     PropertyDetails details(descriptors->GetDetails(i));
-    Object** slot = descriptors->GetValueSlot(i);
-
-    if (!(*slot)->IsHeapObject()) continue;
-    HeapObject* value = HeapObject::cast(*slot);
-
-    mark_compact_collector()->RecordSlot(slot, slot, *slot);
 
     switch (details.type()) {
       case NORMAL:
       case FIELD:
       case CONSTANT_FUNCTION:
       case HANDLER:
       case INTERCEPTOR:
         base_marker()->MarkObjectAndPush(value);
         break;
       case CALLBACKS:
@@ skipping 2202 matching lines @@
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 
 
 } }  // namespace v8::internal