Use PassiveObject were possible.

runtime/vm/object.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/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 13078 matching lines @@
 }
 
 
 RawObject* Instance::Evaluate(const String& expr,
                               const Array& param_names,
                               const Array& param_values) const {
   const Class& cls = Class::Handle(clazz());
   const Function& eval_func =
       Function::Handle(EvaluateHelper(cls, expr, param_names, false));
   const Array& args = Array::Handle(Array::New(1 + param_values.Length()));
-  Object& param = Object::Handle();
+  PassiveObject& param = PassiveObject::Handle();
   args.SetAt(0, *this);
   for (intptr_t i = 0; i < param_values.Length(); i++) {
     param = param_values.At(i);
     args.SetAt(i + 1, param);
   }
-  const Object& result =
-      Object::Handle(DartEntry::InvokeFunction(eval_func, args));
+  const PassiveObject& result =
+      PassiveObject::Handle(DartEntry::InvokeFunction(eval_func, args));
   return result.raw();
 }
 
 
 RawObject* Instance::HashCode() const {
   // TODO(koda): Optimize for all builtin classes and all classes
   // that do not override hashCode.
   return DartLibraryCalls::HashCode(*this);
 }
 
@@ skipping 211 matching lines @@
     other_type_arguments = other.arguments();
   }
   return cls.IsSubtypeOf(type_arguments, other_class, other_type_arguments,
                          bound_error);
 }
 
 
 bool Instance::OperatorEquals(const Instance& other) const {
   // TODO(koda): Optimize for all builtin classes and all classes
   // that do not override operator==.
-  const Object& result =
-      Object::Handle(DartLibraryCalls::Equals(*this, other));
+  const PassiveObject& result =
+      PassiveObject::Handle(DartLibraryCalls::Equals(*this, other));
   return result.raw() == Object::bool_true().raw();

[Ivan Posva, 2014/08/28 19:31:53]

I don't think we need to wrap it in a handle to compare the raw values with a VM
predefined object.

[siva, 2014/08/29 00:17:01]

Done.

 }
 
 
 bool Instance::IsIdenticalTo(const Instance& other) const {
   if (raw() == other.raw()) return true;
   if (IsInteger() && other.IsInteger()) {
     return Integer::Cast(*this).Equals(other);
   }
   if (IsDouble() && other.IsDouble()) {
     return Double::Cast(*this).CanonicalizeEquals(other);
@@ skipping 4755 matching lines @@
       JSONObject jselement(&jsarr);
       jselement.AddProperty("index", index);
 
       Object& element = Object::Handle(At(index));
       jselement.AddProperty("value", element);
     }
   }
 }
 
 
 RawArray* Array::Grow(const Array& source,

[Ivan Posva, 2014/08/28 19:31:53]

Should we be requiring the isolate be passed into this as the first parameter?

[siva, 2014/08/29 00:17:01]

I added a local variable isolate and used that in all the three
handle creation calls here.

On 2014/08/28 19:31:53, Ivan Posva wrote:

                       intptr_t new_length,
                       Heap::Space space) {
   const Array& result = Array::Handle(Array::New(new_length, space));
   intptr_t len = 0;
   if (!source.IsNull()) {
     len = source.Length();
     result.SetTypeArguments(TypeArguments::Handle(source.GetTypeArguments()));
   }
   ASSERT(new_length >= len);  // Cannot copy 'source' into new array.
   ASSERT(new_length != len);  // Unnecessary copying of array.
-  Object& obj = Object::Handle();
+  PassiveObject& obj = PassiveObject::Handle();
   for (int i = 0; i < len; i++) {
     obj = source.At(i);
     result.SetAt(i, obj);
   }
   return result.raw();
 }
 
 
 RawArray* Array::MakeArray(const GrowableObjectArray& growable_array) {
   ASSERT(!growable_array.IsNull());
@@ skipping 99 matching lines @@
       Array::Handle(Array::Grow(contents, new_capacity, space));
   StorePointer(&(raw_ptr()->data_), new_contents.raw());
 }
 
 
 RawObject* GrowableObjectArray::RemoveLast() const {
   ASSERT(!IsNull());
   ASSERT(Length() > 0);
   intptr_t index = Length() - 1;
   const Array& contents = Array::Handle(data());
-  const Object& obj = Object::Handle(contents.At(index));
+  const PassiveObject& obj = PassiveObject::Handle(contents.At(index));
   contents.SetAt(index, Object::null_object());
   SetLength(index);
   return obj.raw();
 }
 
 
 bool GrowableObjectArray::CanonicalizeEquals(const Instance& other) const {
   // If both handles point to the same raw instance they are equal.
   if (this->raw() == other.raw()) {
     return true;
@@ skipping 141 matching lines @@
   if (!map.UpdateOrInsert(key, value)) {
     SetModified();
   }
   StorePointer(&raw_ptr()->data_, map.Release().raw());
 }
 
 
 RawObject* LinkedHashMap::LookUp(const Object& key) const {
   ASSERT(!IsNull());
   EnumIndexDefaultMap map(data());
-  const Object& result = Object::Handle(map.GetOrNull(key));
+  const PassiveObject& result = PassiveObject::Handle(map.GetOrNull(key));
   ASSERT(map.Release().raw() == data());

[Ivan Posva, 2014/08/28 19:31:53]

You could stick the ASSERT in a NoGCScope and then we do not need to
wrap/unwrap.

[siva, 2014/08/29 00:17:01]

Done.

   return result.raw();
 }
 
 
 bool LinkedHashMap::Contains(const Object& key) const {
   ASSERT(!IsNull());
   EnumIndexDefaultMap map(data());
   bool result = map.ContainsKey(key);
   ASSERT(map.Release().raw() == data());
   return result;
 }
 
 
 RawObject* LinkedHashMap::Remove(const Object& key) const {
   ASSERT(!IsNull());
   EnumIndexDefaultMap map(data());
   // TODO(koda): Make 'Remove' also return the old value.
-  const Object& result = Object::Handle(map.GetOrNull(key));
+  const PassiveObject& result = PassiveObject::Handle(map.GetOrNull(key));
   if (map.Remove(key)) {
     SetModified();
   }
   StorePointer(&raw_ptr()->data_, map.Release().raw());
   return result.raw();
 }
 
 
 void LinkedHashMap::Clear() const {
   ASSERT(!IsNull());
@@ skipping 640 matching lines @@
   }
   result.set_code_array(code_array);
   result.set_pc_offset_array(pc_offset_array);
   result.SetCatchStacktrace(Object::empty_array(),
                             Object::empty_array());
   result.set_expand_inlined(true);  // default.
   return result.raw();
 }
 
 
 void Stacktrace::Append(const Array& code_list,

[Ivan Posva, 2014/08/28 19:31:53]

Pass in isolate over here?

[siva, 2014/08/29 00:17:01]

I added a local variable isolate and used that in all the handle
creation in this function.

On 2014/08/28 19:31:53, Ivan Posva wrote:

                         const Array& pc_offset_list,
                         const intptr_t start_index) const {
   ASSERT(start_index <= code_list.Length());
   ASSERT(pc_offset_list.Length() == code_list.Length());
   intptr_t old_length = Length();
   intptr_t new_length = old_length + pc_offset_list.Length() - start_index;
   if (new_length == old_length) {
     // Nothing to append. Avoid work and an assert that growing arrays always
     // increases their size.
     return;
   }
 
   // Grow the arrays for code, pc_offset pairs to accommodate the new stack
   // frames.
   Array& code_array = Array::Handle(raw_ptr()->code_array_);
   Array& pc_offset_array = Array::Handle(raw_ptr()->pc_offset_array_);
   code_array = Array::Grow(code_array, new_length);
   pc_offset_array = Array::Grow(pc_offset_array, new_length);
   set_code_array(code_array);
   set_pc_offset_array(pc_offset_array);
   // Now append the new function and code list to the existing arrays.
   intptr_t j = start_index;
-  Object& obj = Object::Handle();
+  PassiveObject& obj = PassiveObject::Handle();
   for (intptr_t i = old_length; i < new_length; i++, j++) {
     obj = code_list.At(j);
     code_array.SetAt(i, obj);
     obj = pc_offset_list.At(j);
     pc_offset_array.SetAt(i, obj);
   }
 }
 
 
 void Stacktrace::SetCatchStacktrace(const Array& code_array,
@@ skipping 452 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart