Avoid allocating an exception object in the snapshot reader.

runtime/vm/object_store.cc

 // 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.
 
 #include "vm/object_store.h"
 
 #include "vm/exceptions.h"
 #include "vm/dart_entry.h"
 #include "vm/isolate.h"
 #include "vm/object.h"
@@ skipping 114 matching lines @@
   set_stack_overflow(Instance::Cast(result));
 
   result = DartLibraryCalls::InstanceCreate(library,
                                             Symbols::OutOfMemoryError(),
                                             Symbols::Dot(),
                                             Object::empty_array());
   if (result.IsError()) {
     return false;
   }
   set_out_of_memory(Instance::Cast(result));
+
+  const UnhandledException& unhandled_exception = UnhandledException::Handle(
+      UnhandledException::New(Instance::Cast(result), Instance::Handle()));

[siva, 2014/07/16 01:00:13]

maybe add a comment here that the preallocated unhandled exception
object is initialized with the out of memory exception object to
make it clear.

[Florian Schneider, 2014/07/16 11:15:42]

Done.

+  set_preallocated_unhandled_exception(unhandled_exception);
+
   const Array& code_array = Array::Handle(
       isolate,
       Array::New(Stacktrace::kPreallocatedStackdepth, Heap::kOld));
   const Array& pc_offset_array = Array::Handle(
       isolate,
       Array::New(Stacktrace::kPreallocatedStackdepth, Heap::kOld));
   const Stacktrace& stack_trace =
       Stacktrace::Handle(Stacktrace::New(code_array, pc_offset_array));
   // Expansion of inlined functions requires additional memory at run time,
   // avoid it.
   stack_trace.set_expand_inlined(false);
   set_preallocated_stack_trace(stack_trace);
 
   return true;
 }
 
 }  // namespace dart