Fix performance regression on some benchmarks: add an extendable array type where push and pop can …

lib/compiler/implementation/ssa/tracer.dart

 // Copyright (c) 2011, 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.
 
 #library('tracer');
 
 #import('dart:io');
 #import('ssa.dart');
 #import('../leg.dart');
 
@@ skipping 154 matching lines @@
 
   String temporaryId(HInstruction instruction) {
     String prefix;
     HType type = instruction.propagatedType;
     if (type.isNonPrimitive()) {
       prefix = 'U';
     } else {
       switch (type) {
         case HType.MUTABLE_ARRAY: prefix = 'm'; break;
         case HType.READABLE_ARRAY: prefix = 'a'; break;
+        case HType.EXTENDABLE_ARRAY: prefix = 'e'; break;
         case HType.BOOLEAN: prefix = 'b'; break;
         case HType.INTEGER: prefix = 'i'; break;
         case HType.DOUBLE: prefix = 'd'; break;
         case HType.NUMBER: prefix = 'n'; break;
         case HType.STRING: prefix = 's'; break;
         case HType.UNKNOWN: prefix = 'v'; break;
         case HType.CONFLICTING: prefix = 'c'; break;
         case HType.STRING_OR_ARRAY: prefix = 'r'; break;
         default: unreachable();
       }
@@ skipping 243 matching lines @@
     String on = node.isOn ? "on" : "off";
     String id = temporaryId(node.guarded);
     return "TypeGuard($on): $id is $type env: $envBuffer";
   }
 
   String visitIs(HIs node) {
     String type = node.typeName.toString();
     return "TypeTest: ${temporaryId(node.expression)} is $type";
   }
 }