Canonicalize all integer constants taht we create by parsing a string.

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 "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 3446 matching lines @@
     UNREACHABLE();
     return false;
   }
   OBJECT_IMPLEMENTATION(Number, Instance);
   friend class Class;
 };
 
 
 class Integer : public Number {
  public:
-  static RawInteger* New(const String& str, Heap::Space space = Heap::kNew);
+  // Returns a canonical Integer object allocated in the old gen space.
+  static RawInteger* NewCanonical(const String& str);
+
   static RawInteger* New(int64_t value, Heap::Space space = Heap::kNew);
 
   virtual double AsDoubleValue() const;
   virtual int64_t AsInt64Value() const;
 
   // Returns 0, -1 or 1.
   virtual int CompareWith(const Integer& other) const;
 
   // Return the most compact presentation of an integer.
   RawInteger* AsValidInteger() const;
@@ skipping 136 matching lines @@
   static const intptr_t kBytesPerElement = kChunkSize;
   static const intptr_t kMaxElements = kSmiMax / kBytesPerElement;
 
   static intptr_t InstanceSize() { return 0; }
 
   static intptr_t InstanceSize(intptr_t len) {
     ASSERT(0 <= len && len <= kMaxElements);
     return RoundedAllocationSize(sizeof(RawBigint) + (len * kBytesPerElement));
   }
 
-  static RawBigint* New(const String& str, Heap::Space space = Heap::kNew);
+  // Returns a canonical Bigint object allocated in the old gen space.
+  static RawBigint* NewCanonical(const String& str);
 
   RawBigint* ArithmeticOp(Token::Kind operation, const Bigint& other) const;
 
  private:
   Chunk GetChunkAt(intptr_t i) const {
     return *ChunkAddr(i);
   }
 
   void SetChunkAt(intptr_t i, Chunk newValue) const {
     *ChunkAddr(i) = newValue;
@@ skipping 2339 matching lines @@
     if (this->CharAt(i) != str.CharAt(begin_index + i)) {
       return false;
     }
   }
   return true;
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_