Allocate the environment's location backing store during register allocation.

runtime/vm/il_printer.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/il_printer.h"
 
 #include "vm/intermediate_language.h"
 #include "vm/os.h"
 #include "vm/parser.h"
 
@@ skipping 757 matching lines @@
 void ParallelMoveInstr::PrintToVisualizer(BufferFormatter* f) const {
   UNIMPLEMENTED();
 }
 
 
 void Environment::PrintTo(BufferFormatter* f) const {
   f->Print(" env={ ");
   for (intptr_t i = 0; i < values_.length(); ++i) {
     if (i > 0) f->Print(", ");
     values_[i]->PrintTo(f);
-    if ((i < locations_.length()) && !locations_[i].IsInvalid()) {
+    if ((locations_ != NULL) && !locations_[i].IsInvalid()) {
       f->Print(" [");
       locations_[i].PrintTo(f);
       f->Print("]");
     }
   }
   f->Print(" }");
 }
 
 }  // namespace dart