When reading a full snapshot use the class id from the snapshot instead of generating a new one. Th…

runtime/vm/heap_histogram.h

-// Copyright (c) 2013, 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_HEAP_HISTOGRAM_H_
-#define VM_HEAP_HISTOGRAM_H_
-
-#include "platform/assert.h"
-#include "vm/flags.h"
-#include "vm/globals.h"
-#include "vm/raw_object.h"
-
-namespace dart {
-
-class JSONStream;
-
-DECLARE_FLAG(bool, print_object_histogram);
-
-// ObjectHistogram is used to compute an average object histogram over
-// the lifetime of an isolate and then print the histogram when the isolate
-// is shut down. Information is gathered at the back-edge of each major GC
-// event. When an object histogram is collected for an isolate, an extra major
-// GC is performed just prior to shutdown.
-class ObjectHistogram {
- public:
-  explicit ObjectHistogram(Isolate* isolate);
-  ~ObjectHistogram();
-
-  // Called when a new class is registered in the isolate.
-  void RegisterClass(const Class& cls);
-
-  // Collect sample for the histogram. Called at back-edge of major GC.
-  void Collect();
-
-  // Print the histogram on stdout.
-  void Print();
-
-  void PrintToJSONStream(JSONStream* stream);
-
- private:
-  // Add obj to histogram
-  void Add(RawObject* obj);
-
-  // For each class an Element keeps track of the accounting.
-  class Element : public ValueObject {
-   public:
-    void Add(int size) {
-      count_++;
-      size_ += size;
-    }
-    intptr_t class_id_;
-    intptr_t count_;
-    intptr_t size_;
-  };
-
-  // Compare function for sorting result.
-  static int compare(const Element** a, const Element** b);
-
-  // This function returns a malloced array. Caller is responsible for calling
-  // free().
-  Element** GetSortedArray(intptr_t* array_length);
-
-  intptr_t major_gc_count_;
-  intptr_t table_length_;
-  Element* table_;
-  Isolate* isolate_;
-
-  friend class ObjectHistogramVisitor;
-
-  DISALLOW_COPY_AND_ASSIGN(ObjectHistogram);
-};
-
-}  // namespace dart
-
-#endif  // VM_HEAP_HISTOGRAM_H_
-