Do not generate some temporary String objects while compiling (field names extracted from getter/se…

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 7151 matching lines @@
   return String::Concat(Symbols::SetterPrefix(), field_name);
 }
 
 
 RawString* Field::SetterSymbol(const String& field_name) {
   return Symbols::FromConcat(Symbols::SetterPrefix(), field_name);
 }
 
 
 RawString* Field::NameFromGetter(const String& getter_name) {
-  return String::SubString(getter_name, strlen(kGetterPrefix));
+  return Symbols::New(getter_name, kGetterPrefixLength,
+      getter_name.Length() - kGetterPrefixLength);
 }
 
 
 RawString* Field::NameFromSetter(const String& setter_name) {
-  return String::SubString(setter_name, strlen(kSetterPrefix));
+  return Symbols::New(setter_name, kSetterPrefixLength,
+      setter_name.Length() - kSetterPrefixLength);
 }
 
 
 bool Field::IsGetterName(const String& function_name) {
   return function_name.StartsWith(Symbols::GetterPrefix());
 }
 
 
 bool Field::IsSetterName(const String& function_name) {
   return function_name.StartsWith(Symbols::SetterPrefix());
@@ skipping 14197 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart