Created methods to surface zone memory information for each isolate and thread in JSON.

runtime/vm/zone.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 RUNTIME_VM_ZONE_H_
 #define RUNTIME_VM_ZONE_H_
 
 #include "platform/utils.h"
 #include "vm/allocation.h"
 #include "vm/handles.h"
+#include "vm/json_stream.h"
 #include "vm/thread.h"
 #include "vm/memory_region.h"
 
 namespace dart {
 
 // Zones support very fast allocation of small chunks of memory. The
 // chunks cannot be deallocated individually, but instead zones
 // support deallocating all chunks in one fast operation.
 
 class Zone {
@@ skipping 37 matching lines @@
   // These calls are deprecated. Do not add further calls to these functions.
   // instead use OS::SCreate and OS::VSCreate.
   // Make a zone-allocated string based on printf format and args.
   char* PrintToString(const char* format, ...) PRINTF_ATTRIBUTE(2, 3);
   char* VPrint(const char* format, va_list args);
 
   // Compute the total size of this zone. This includes wasted space that is
   // due to internal fragmentation in the segments.
   intptr_t SizeInBytes() const;
 
+  // Computes the amount of space used in the zone.
+  intptr_t UsedSizeInBytes() const {
+    return SizeInBytes() - (limit_ - position_);
+  }
+
   // Structure for managing handles allocation.
   VMHandles* handles() { return &handles_; }
 
   void VisitObjectPointers(ObjectPointerVisitor* visitor);
 
   Zone* previous() const { return previous_; }
 
+#ifndef PRODUCT
+  void PrintJSON(JSONStream* stream) const;
+#endif
+
  private:
   Zone();
   ~Zone();  // Delete all memory associated with the zone.
 
   // All pointers returned from AllocateUnsafe() and New() have this alignment.
   static const intptr_t kAlignment = kDoubleSize;
 
   // Default initial chunk size.
   static const intptr_t kInitialChunkSize = 1 * KB;
 
@@ skipping 82 matching lines @@
   // Create an empty zone and set is at the current zone for the Thread.
   explicit StackZone(Thread* thread);
 
   // Delete all memory associated with the zone.
   ~StackZone();
 
   // Compute the total size of this zone. This includes wasted space that is
   // due to internal fragmentation in the segments.
   intptr_t SizeInBytes() const { return zone_.SizeInBytes(); }
 
+  // Computes the used space in the zone.
+  intptr_t UsedSizeInBytes() const { return zone_.UsedSizeInBytes(); }
+
   Zone* GetZone() { return &zone_; }
 
  private:
   Zone zone_;
 
   template <typename T>
   friend class GrowableArray;
   template <typename T>
   friend class ZoneGrowableArray;
 
@@ skipping 65 matching lines @@
   if (old_data != 0) {
     memmove(reinterpret_cast<void*>(new_data),
             reinterpret_cast<void*>(old_data), old_len * kElementSize);
   }
   return new_data;
 }
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_ZONE_H_