Move types out of the HInstructions.

lib/compiler/implementation/ssa/types.dart

 // 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.
 
 abstract class HType {
   const HType();
 
   /**
    * Returns an [HType] that represents [type] and all types that have
    * [type] as supertype.
@@ skipping 744 matching lines @@
   HType intersection(HType other) {
     if (other.isString()) return HType.STRING;
     if (other.isStringOrNull()) {
       return canBeNull() ? HType.STRING_OR_NULL : HType.STRING;
     }
     if (other.isReadableArray()) return HType.CONFLICTING;
     if (other.isIndexablePrimitive()) return HType.STRING;
     return super.intersection(other);
   }
 }
+
+class HTypeMap {
+  Map<HInstruction, HType> _map;
+
+  HTypeMap() : _map = new Map<HInstruction, HType>();
+
+  operator [](HInstruction instruction) {
+    HType result = _map[instruction];
+    if (result == null) return instruction.guaranteedType;
+    return result;
+  }
+
+  operator []=(HInstruction instruction, HType value) {
+    _map[instruction] = value;
+  }
+}