- Represent strings internally in UTF-16 format, this makes it

runtime/vm/flow_graph_compiler.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/globals.h"  // Needed here to get TARGET_ARCH_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
@@ skipping 522 matching lines @@
   CheckClassIds(kClassIdReg, args, is_instance_lbl, is_not_instance_lbl);
 }
 
 
 void FlowGraphCompiler::GenerateStringTypeCheck(Register kClassIdReg,
                                                 Label* is_instance_lbl,
                                                 Label* is_not_instance_lbl) {
   GrowableArray<intptr_t> args;
   args.Add(kOneByteStringCid);
   args.Add(kTwoByteStringCid);
-  args.Add(kFourByteStringCid);
   args.Add(kExternalOneByteStringCid);
   args.Add(kExternalTwoByteStringCid);
-  args.Add(kExternalFourByteStringCid);
   CheckClassIds(kClassIdReg, args, is_instance_lbl, is_not_instance_lbl);
 }
 
 
 void FlowGraphCompiler::GenerateListTypeCheck(Register kClassIdReg,
                                               Label* is_instance_lbl) {
   Label unknown;
   GrowableArray<intptr_t> args;
   args.Add(kArrayCid);
   args.Add(kGrowableObjectArrayCid);
@@ skipping 362 matching lines @@
       ASSERT(Utils::IsInt(31, disp));
       return FieldAddress(array, disp);
     }
     default:
       UNIMPLEMENTED();
       return FieldAddress(SPREG, 0);
   }
 }
 
 }  // namespace dart