Box values of LoadCodeUnits that fall outside of smi range on 32bit platforms.

runtime/vm/intermediate_language_x64.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/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
@@ skipping 1113 matching lines @@
       __ SmiTag(result);
       break;
     default:
       ASSERT((class_id() == kArrayCid) || (class_id() == kImmutableArrayCid));
       __ movq(result, element_address);
       break;
   }
 }
 
 
-Representation LoadCodeUnitsInstr::representation() const {
-  switch (class_id()) {
-    case kOneByteStringCid:
-    case kTwoByteStringCid:
-    case kExternalOneByteStringCid:
-    case kExternalTwoByteStringCid:
-      return kTagged;
-    default:
-      UNIMPLEMENTED();
-      return kTagged;
-  }
-}
-
-
 LocationSummary* LoadCodeUnitsInstr::MakeLocationSummary(Isolate* isolate,
                                                          bool opt) const {
   const intptr_t kNumInputs = 2;
   const intptr_t kNumTemps = 0;
   LocationSummary* summary = new(isolate) LocationSummary(
       isolate, kNumInputs, kNumTemps, LocationSummary::kNoCall);
   summary->set_in(0, Location::RequiresRegister());
   // The smi index is either untagged (element size == 1), or it is left smi
   // tagged (for all element sizes > 1).
   summary->set_in(1, index_scale() == 1 ? Location::WritableRegister()
@@ skipping 5239 matching lines @@
   __ movq(R10, Immediate(kInvalidObjectPointer));
   __ movq(RBX, Immediate(kInvalidObjectPointer));
 #endif
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64