Don't leak memory between iterations of the message serialization benchmarks.

runtime/vm/benchmark_test.cc

 // 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.
 
 #include "vm/benchmark_test.h"
 
 #include "bin/builtin.h"
 #include "bin/file.h"
 
 #include "platform/assert.h"
@@ skipping 493 matching lines @@
 
 
 BENCHMARK(SerializeNull) {
   const Object& null_object = Object::Handle();
   const intptr_t kLoopCount = 1000000;
   Isolate* isolate = Isolate::Current();
   uint8_t* buffer;
   Timer timer(true, "Serialize Null");
   timer.Start();
   for (intptr_t i = 0; i < kLoopCount; i++) {
+    StackZone zone(isolate);
     MessageWriter writer(&buffer, &message_allocator);
     writer.WriteMessage(null_object);
     intptr_t buffer_len = writer.BytesWritten();
 
     // Read object back from the snapshot.
     SnapshotReader reader(buffer, buffer_len, Snapshot::kMessage, isolate);
     reader.ReadObject();
   }
   timer.Stop();
   int64_t elapsed_time = timer.TotalElapsedTime();
   benchmark->set_score(elapsed_time);
 }
 
 
 BENCHMARK(SerializeSmi) {
   const Integer& smi_object = Integer::Handle(Smi::New(42));
   const intptr_t kLoopCount = 1000000;
   Isolate* isolate = Isolate::Current();
   uint8_t* buffer;
   Timer timer(true, "Serialize Smi");
   timer.Start();
   for (intptr_t i = 0; i < kLoopCount; i++) {
+    StackZone zone(isolate);
     MessageWriter writer(&buffer, &message_allocator);
     writer.WriteMessage(smi_object);
     intptr_t buffer_len = writer.BytesWritten();
 
     // Read object back from the snapshot.
     SnapshotReader reader(buffer, buffer_len, Snapshot::kMessage, isolate);
     reader.ReadObject();
   }
   timer.Stop();
   int64_t elapsed_time = timer.TotalElapsedTime();
   benchmark->set_score(elapsed_time);
 }
 
 
 BENCHMARK(SimpleMessage) {
   const Array& array_object = Array::Handle(Array::New(2));
   array_object.SetAt(0, Integer::Handle(Smi::New(42)));
   array_object.SetAt(1, Object::Handle());
   const intptr_t kLoopCount = 1000000;
   Isolate* isolate = Isolate::Current();
   uint8_t* buffer;
   Timer timer(true, "Simple Message");
   timer.Start();
   for (intptr_t i = 0; i < kLoopCount; i++) {
+    StackZone zone(isolate);
     MessageWriter writer(&buffer, &malloc_allocator);
     writer.WriteMessage(array_object);
     intptr_t buffer_len = writer.BytesWritten();
 
     // Read object back from the snapshot.
     SnapshotReader reader(buffer, buffer_len, Snapshot::kMessage, isolate);
     reader.ReadObject();
     free(buffer);
   }
   timer.Stop();
   int64_t elapsed_time = timer.TotalElapsedTime();
   benchmark->set_score(elapsed_time);
 }
 
 }  // namespace dart