Reland r24563 and r24564 with fixes cumbersome API leading to leaks.

runtime/vm/gc_marker.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/gc_marker.h"
 
 #include <map>
 #include <utility>
 
 #include "vm/allocation.h"
@@ skipping 361 matching lines @@
       !raw_key->IsMarked()) {
     // Key is white.  Delay the weak property.
     visitor->DelayWeakProperty(raw_weak);
   } else {
     // Key is gray or black.  Make the weak property black.
     raw_weak->VisitPointers(visitor);
   }
 }
 
 
-void GCMarker::ProcessPeerReferents(PageSpace* page_space) {
-  PageSpace::PeerTable* peer_table = page_space->GetPeerTable();
-  PageSpace::PeerTable::iterator it = peer_table->begin();
-  while (it != peer_table->end()) {
-    RawObject* raw_obj = it->first;
-    ASSERT(raw_obj->IsHeapObject());
-    if (raw_obj->IsMarked()) {
-      // The object has survived.  Do nothing.
-      ++it;
-    } else {
-      // The object has become garbage.  Remove its record.
-      peer_table->erase(it++);
+void GCMarker::ProcessWeakTables(PageSpace* page_space) {
+  for (int sel = 0;
+       sel < Heap::kNumWeakSelectors;
+       sel++) {
+    WeakTable* table = heap_->GetWeakTable(
+        Heap::kOld, static_cast<Heap::WeakSelector>(sel));
+    intptr_t size = table->size();
+    for (intptr_t i = 0; i < size; i++) {
+      if (table->IsValidEntryAt(i)) {
+        RawObject* raw_obj = table->ObjectAt(i);
+        ASSERT(raw_obj->IsHeapObject());
+        if (!raw_obj->IsMarked()) {
+          table->InvalidateAt(i);
+        }
+      }
     }
   }
 }
 
 
 void GCMarker::MarkObjects(Isolate* isolate,
                            PageSpace* page_space,
                            bool invoke_api_callbacks) {
   MarkingStack marking_stack;
   Prologue(isolate, invoke_api_callbacks);
   MarkingVisitor mark(isolate, heap_, page_space, &marking_stack);
   IterateRoots(isolate, &mark, !invoke_api_callbacks);
   DrainMarkingStack(isolate, &mark);
   IterateWeakReferences(isolate, &mark);
   MarkingWeakVisitor mark_weak;
   IterateWeakRoots(isolate, &mark_weak, invoke_api_callbacks);
   mark.Finalize();
-  ProcessPeerReferents(page_space);
+  ProcessWeakTables(page_space);
   Epilogue(isolate, invoke_api_callbacks);
 }
 
 }  // namespace dart