Generate artificial hashCode for often used classes.

pkg/analysis_server/lib/src/services/index/index.dart

Index: pkg/analysis_server/lib/src/services/index/index.dart
diff --git a/pkg/analysis_server/lib/src/services/index/index.dart b/pkg/analysis_server/lib/src/services/index/index.dart
index e80a190e3281821f7d11e976e7fe733c8baacc39..cea7395cd6fea61badcdcba65c018e937cccd6f9 100644
--- a/pkg/analysis_server/lib/src/services/index/index.dart
+++ b/pkg/analysis_server/lib/src/services/index/index.dart
@@ -320,6 +320,16 @@ class Relationship {
   static Map<String, Relationship> _RELATIONSHIP_MAP = {};
 
   /**
+   * The next artificial hash code.
+   */
+  static int _NEXT_HASH_CODE = 0;
+
+  /**
+   * The artifitial hash code for this object.
+   */
+  final int _hashCode = _NEXT_HASH_CODE++;

[kasperl, 2015/02/18 08:04:16]

Have you considered masking here? If you start overflowing the smi limit, you
might get considerably worse performance.

[scheglov, 2015/02/18 17:20:32]

Good question.
See https://codereview.chromium.org/936823002

+
+  /**
    * The unique identifier for this relationship.
    */
   final String identifier;
@@ -330,6 +340,9 @@ class Relationship {
   Relationship(this.identifier);
 
   @override
+  int get hashCode => _hashCode;
+
+  @override
   String toString() => identifier;
 
   /**