Workaround for http://crbug.com/9746:...

src/mark-compact.cc

 // Copyright 2006-2008 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 78 matching lines @@
   Finish();
 
   // Save the count of marked objects remaining after the collection and
   // null out the GC tracer.
   previous_marked_count_ = tracer_->marked_count();
   ASSERT(previous_marked_count_ == 0);
   tracer_ = NULL;
 }
 
 
+#ifdef DEBUG
+// Helper class for verifying the symbol table.
+class SymbolTableVerifier : public ObjectVisitor {
+ public:
+  SymbolTableVerifier() { }
+  void VisitPointers(Object** start, Object** end) {
+    // Visit all HeapObject pointers in [start, end).
+    for (Object** p = start; p < end; p++) {
+      if ((*p)->IsHeapObject()) {
+        // Check that the symbol is actually a symbol.
+        ASSERT((*p)->IsNull() || (*p)->IsUndefined() || (*p)->IsSymbol());
+      }
+    }
+  }
+};
+#endif  // DEBUG
+
+
 void MarkCompactCollector::Prepare(GCTracer* tracer) {
   // Rather than passing the tracer around we stash it in a static member
   // variable.
   tracer_ = tracer;
 
   static const int kFragmentationLimit = 50;  // Percent.
 #ifdef DEBUG
   ASSERT(state_ == IDLE);
   state_ = PREPARE_GC;
 #endif
@@ skipping 32 matching lines @@
     Page::set_rset_state(Page::NOT_IN_USE);
   }
 #endif
 
   PagedSpaces spaces;
   while (PagedSpace* space = spaces.next()) {
     space->PrepareForMarkCompact(compacting_collection_);
   }
 
 #ifdef DEBUG
+  SymbolTable* symbol_table = SymbolTable::cast(Heap::symbol_table());
+  SymbolTableVerifier v;
+  symbol_table->IterateElements(&v);
+
   live_bytes_ = 0;
   live_young_objects_ = 0;
   live_old_pointer_objects_ = 0;
   live_old_data_objects_ = 0;
   live_code_objects_ = 0;
   live_map_objects_ = 0;
   live_lo_objects_ = 0;
 #endif
 }
 
@@ skipping 1597 matching lines @@
 
 void MarkCompactCollector::RebuildRSets() {
 #ifdef DEBUG
   ASSERT(state_ == RELOCATE_OBJECTS);
   state_ = REBUILD_RSETS;
 #endif
   Heap::RebuildRSets();
 }
 
 } }  // namespace v8::internal