Remove assumption from the heap verifier that objects occupy a narrow range of the address space.

runtime/vm/scavenger.h

 // 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.
 
 #ifndef VM_SCAVENGER_H_
 #define VM_SCAVENGER_H_
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/dart.h"
 #include "vm/flags.h"
 #include "vm/globals.h"
 #include "vm/raw_object.h"
 #include "vm/ring_buffer.h"
 #include "vm/spaces.h"
 #include "vm/virtual_memory.h"
 #include "vm/visitor.h"
 
 namespace dart {
 
 // Forward declarations.
 class Heap;
 class Isolate;
 class JSONObject;
+class ObjectSet;
 class ScavengerVisitor;
 
 // Wrapper around VirtualMemory that adds caching and handles the empty case.
 class SemiSpace {
  public:
   static void InitOnce();
 
   // Get a space of the given size. Returns NULL on out of memory. If size is 0,
   // returns an empty space: pointer(), start() and end() all return NULL.
   static SemiSpace* New(intptr_t size_in_words);
@@ skipping 139 matching lines @@
     SpaceUsage usage;
     usage.used_in_words = UsedInWords();
     usage.capacity_in_words = CapacityInWords();
     usage.external_in_words = ExternalInWords();
     return usage;
   }
 
   void VisitObjects(ObjectVisitor* visitor) const;
   void VisitObjectPointers(ObjectPointerVisitor* visitor) const;
 
-  void StartEndAddress(uword* start, uword* end) const {
-    *start = to_->start();
-    *end = to_->end();
-  }
+  void AddRegionsToObjectSet(ObjectSet* set) const;
 
   void WriteProtect(bool read_only);
 
   void AddGCTime(int64_t micros) {
     gc_time_micros_ += micros;
   }
 
   int64_t gc_time_micros() const {
     return gc_time_micros_;
   }
@@ skipping 110 matching lines @@
 
   friend class ScavengerVisitor;
   friend class ScavengerWeakVisitor;
 
   DISALLOW_COPY_AND_ASSIGN(Scavenger);
 };
 
 }  // namespace dart
 
 #endif  // VM_SCAVENGER_H_