Add Instance::HashCode that matches hashCode.

runtime/vm/object.h

 // 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.
 
 #ifndef VM_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include <limits>
 #include "include/dart_api.h"
 #include "platform/assert.h"
@@ skipping 4230 matching lines @@
 
   // Evaluate the given expression as if it appeared in an instance
   // method of this instance and return the resulting value, or an
   // error object if evaluating the expression fails. The method has
   // the formal parameters given in param_names, and is invoked with
   // the argument values given in param_values.
   RawObject* Evaluate(const String& expr,
                       const Array& param_names,
                       const Array& param_values) const;
 
+  // Equivalent to invoking hashCode on this instance.
+  virtual RawObject* HashCode() const;
+
   static intptr_t InstanceSize() {
     return RoundedAllocationSize(sizeof(RawInstance));
   }
 
   static RawInstance* New(const Class& cls, Heap::Space space = Heap::kNew);
 
   // Array/list element address computations.
   static intptr_t DataOffsetFor(intptr_t cid);
   static intptr_t ElementSizeFor(intptr_t cid);
 
@@ skipping 678 matching lines @@
     return Equals(other);
   }
   virtual bool CanonicalizeEquals(const Instance& other) const {
     return Equals(other);
   }
   virtual bool Equals(const Instance& other) const {
     UNREACHABLE();
     return false;
   }
 
+  virtual RawObject* HashCode() const { return raw(); }
+
   // Integer is an abstract class.
   virtual bool IsZero() const {
     UNREACHABLE();
     return false;
   }
   virtual bool IsNegative() const {
     // Number is an abstract class.
     UNREACHABLE();
     return false;
   }
@@ skipping 351 matching lines @@
     this->SetHash(result);
     return result;
   }
 
   static intptr_t hash_offset() { return OFFSET_OF(RawString, hash_); }
   static intptr_t Hash(const String& str, intptr_t begin_index, intptr_t len);
   static intptr_t Hash(const uint8_t* characters, intptr_t len);
   static intptr_t Hash(const uint16_t* characters, intptr_t len);
   static intptr_t Hash(const int32_t* characters, intptr_t len);
 
+  virtual RawObject* HashCode() const { return Integer::New(Hash()); }
+
   int32_t CharAt(intptr_t index) const;
 
   Scanner::CharAtFunc CharAtFunc() const;
 
   intptr_t CharSize() const;
 
   inline bool Equals(const String& str) const;
   inline bool Equals(const String& str,
                      intptr_t begin_index,  // begin index on 'str'.
                      intptr_t len) const;  // len on 'str'.
@@ skipping 1802 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_