Phantom references support internal fields

src/heap/mark-compact.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
@@ skipping 286 matching lines @@
   DCHECK(heap_->incremental_marking()->IsStopped());
 
   if (FLAG_collect_maps) ClearNonLiveReferences();
 
   ProcessAndClearWeakCells();
 
   ClearWeakCollections();
 
   heap_->set_encountered_weak_cells(Smi::FromInt(0));
 
+  isolate()->global_handles()->CollectPhantomCallbackData();
+
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap) {
     VerifyMarking(heap_);
   }
 #endif
 
   SweepSpaces();
 
 #ifdef VERIFY_HEAP
   if (heap()->weak_embedded_objects_verification_enabled()) {
@@ skipping 1889 matching lines @@
   // The objects reachable from the roots, weak maps or object groups
   // are marked, yet unreachable objects are unmarked.  Mark objects
   // reachable only from weak global handles.
   //
   // First we identify nonlive weak handles and mark them as pending
   // destruction.
   heap()->isolate()->global_handles()->IdentifyWeakHandles(
       &IsUnmarkedHeapObject);
   // Then we mark the objects and process the transitive closure.
   heap()->isolate()->global_handles()->IterateWeakRoots(&root_visitor);
-  while (marking_deque_.overflowed()) {
-    RefillMarkingDeque();
-    EmptyMarkingDeque();
-  }
+
+  ProcessMarkingDeque();

[jochen (gone - plz use gerrit), 2014/12/02 10:25:59]

this is not needed, because the following call to ProcessEphemeralMarking
processes the deque anyways

[Erik Corry, 2014/12/02 10:40:49]

I think this is wrong, and it is needed.

Nothing in the ProcessEphemeralMarking will check for an overflowed marking
deque, before the work_to_do variable is set.  That means it can be incorrectly
set to false, and the ephemeral iteration can terminate early.

 
   // Repeat host application specific and Harmony weak maps marking to
   // mark unmarked objects reachable from the weak roots.
   ProcessEphemeralMarking(&root_visitor);
 
   AfterMarking();
 
   if (FLAG_print_cumulative_gc_stat) {
     heap_->tracer()->AddMarkingTime(base::OS::TimeCurrentMillis() - start_time);
   }
@@ skipping 2180 matching lines @@
   SlotsBuffer* buffer = *buffer_address;
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 }
 }  // namespace v8::internal