Don't overload FreeListElement for become.

runtime/vm/class_table.cc

 // Copyright (c) 2012, 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/atomic.h"
 #include "vm/class_table.h"
 #include "vm/flags.h"
 #include "vm/freelist.h"
 #include "vm/growable_array.h"
 #include "vm/heap.h"
@@ skipping 17 matching lines @@
   } else {
     // Duplicate the class table from the VM isolate.
     ClassTable* vm_class_table = Dart::vm_isolate()->class_table();
     capacity_ = vm_class_table->capacity_;
     table_ = reinterpret_cast<RawClass**>(
         calloc(capacity_, sizeof(RawClass*)));  // NOLINT
     for (intptr_t i = kObjectCid; i < kInstanceCid; i++) {
       table_[i] = vm_class_table->At(i);
     }
     table_[kFreeListElement] = vm_class_table->At(kFreeListElement);
+    table_[kForwardingCorpse] = vm_class_table->At(kForwardingCorpse);
     table_[kDynamicCid] = vm_class_table->At(kDynamicCid);
     table_[kVoidCid] = vm_class_table->At(kVoidCid);
     class_heap_stats_table_ = reinterpret_cast<ClassHeapStats*>(
         calloc(capacity_, sizeof(ClassHeapStats)));  // NOLINT
     for (intptr_t i = 0; i < capacity_; i++) {
       class_heap_stats_table_[i].Initialize();
     }
   }
   predefined_class_heap_stats_table_ = reinterpret_cast<ClassHeapStats*>(
         calloc(kNumPredefinedCids, sizeof(ClassHeapStats)));  // NOLINT
@@ skipping 163 matching lines @@
 
 
 void ClassTable::Print() {
   Class& cls = Class::Handle();
   String& name = String::Handle();
 
   for (intptr_t i = 1; i < top_; i++) {
     if (!HasValidClassAt(i)) {
       continue;
     }
-    if (i == kFreeListElement) {
+    if (i == kFreeListElement || i == kForwardingCorpse) {

[Cutch, 2016/06/02 14:09:53]

This continue shouldn't be necessary anymore because we can now call Name on
both free list and forwarding corpse classes?

[rmacnak, 2016/06/02 17:57:06]

Done.

       continue;
     }
     cls = At(i);
     if (cls.raw() != reinterpret_cast<RawClass*>(0)) {
       name = cls.Name();
       OS::Print("%" Pd ": %s\n", i, name.ToCString());
     }
   }
 }
 
@@ skipping 156 matching lines @@
   ASSERT(cid > 0);
   if (cid < kNumPredefinedCids) {
     return &predefined_class_heap_stats_table_[cid];
   }
   ASSERT(cid < top_);
   return &class_heap_stats_table_[cid];
 }
 
 
 ClassHeapStats* ClassTable::StatsWithUpdatedSize(intptr_t cid) {
-  if (!HasValidClassAt(cid) || (cid == kFreeListElement) || (cid == kSmiCid)) {
+  if (!HasValidClassAt(cid) ||
+      (cid == kFreeListElement) ||
+      (cid == kForwardingCorpse) ||
+      (cid == kSmiCid)) {
     return NULL;
   }
   Class& cls = Class::Handle(At(cid));
   if (!(cls.is_finalized() || cls.is_prefinalized())) {
     // Not finalized.
     return NULL;
   }
   ClassHeapStats* stats = PreliminaryStatsAt(cid);
   if (ShouldUpdateSizeForClassId(cid)) {
     stats->UpdateSize(cls.instance_size());
@@ skipping 139 matching lines @@
 
 void ClassTable::UpdateLiveNew(intptr_t cid, intptr_t size) {
   ClassHeapStats* stats = PreliminaryStatsAt(cid);
   ASSERT(stats != NULL);
   ASSERT(size >= 0);
   stats->post_gc.AddNew(size);
 }
 
 
 }  // namespace dart