Fix allocation stats bug on ARM; add unit test.

runtime/vm/class_table.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_CLASS_TABLE_H_
 #define VM_CLASS_TABLE_H_
 
 #include "platform/assert.h"
 #include "vm/globals.h"
 
@@ skipping 42 matching lines @@
     old_size = 0;
   }
 
   // For classes with fixed instance size we do not emit code to update
   // the size statistics. Update them by calling this method.
   void UpdateSize(intptr_t instance_size) {
     ASSERT(instance_size > 0);
     old_size = old_count * instance_size;
     new_size = new_count * instance_size;
   }
+
+  void Verify() {
+    ASSERT(new_count >= 0);
+    ASSERT(new_size >= 0);
+    ASSERT(old_count >= 0);
+    ASSERT(old_size >= 0);
+  }
 };
 
 class ClassHeapStats {
  public:
   // Snapshot before GC.
   AllocStats<intptr_t> pre_gc;
   // Live after GC.
   AllocStats<intptr_t> post_gc;
   // Allocations since the last GC.
   AllocStats<intptr_t> recent;
@@ skipping 27 matching lines @@
   void ResetAtOldGC();
   void ResetAccumulator();
   void UpdatePromotedAfterNewGC();
   void UpdateSize(intptr_t instance_size);
   void PrintToJSONObject(const Class& cls, JSONObject* obj) const;
 
  private:
   // Recent old at start of last new GC (used to compute promoted_*).
   intptr_t old_pre_new_gc_count_;
   intptr_t old_pre_new_gc_size_;
+
+  void Verify();
 };
 
 
 class ClassTable {
  public:
   ClassTable();
   // Create a copy of the original class table only, without copying any of the
   // stats data.
   explicit ClassTable(ClassTable* original);
   ~ClassTable();
@@ skipping 82 matching lines @@
   ClassHeapStats* PreliminaryStatsAt(intptr_t cid);
   void UpdateLiveOld(intptr_t cid, intptr_t size);
   void UpdateLiveNew(intptr_t cid, intptr_t size);
 
   DISALLOW_COPY_AND_ASSIGN(ClassTable);
 };
 
 }  // namespace dart
 
 #endif  // VM_CLASS_TABLE_H_