temp: disable hash improvement

scala · retronym · Mar 9, 2017 · Mar 11, 2017 · Mar 15, 2017 · Mar 12, 2017
commit 79efd96506f5231b6ec94b924d6a62f1e855f0b9
diff --git a/src/reflect/scala/reflect/internal/util/WeakHashSet.scala b/src/reflect/scala/reflect/internal/util/WeakHashSet.scala
@@ -1,9 +1,11 @@
 package scala
 package reflect.internal.util

-import java.lang.ref.{WeakReference, ReferenceQueue}
+import java.lang.ref.{ReferenceQueue, WeakReference}
+
 import scala.annotation.tailrec
 import scala.collection.mutable.{Set => MSet}
+import scala.util.hashing.MurmurHash3

 /**
 * A HashSet where the elements are stored weakly. Elements in this set are eligible for GC if no other
@@ -64,19 +66,13 @@ final class WeakHashSet[A <: AnyRef](val initialCapacity: Int, val loadFactor: D
   * find the bucket associated with an element's hash code
   */
  private[this] def bucketFor(hash: Int): Int = {
-    // spread the bits around to try to avoid accidental collisions using the
-    // same algorithm as java.util.HashMap
-    var h = hash
-    h ^= h >>> 20 ^ h >>> 12
-    h ^= h >>> 7 ^ h >>> 4
-
    // this is finding h % table.length, but takes advantage of the
    // fact that table length is a power of 2,
    // if you don't do bit flipping in your head, if table.length
    // is binary 100000.. (with n 0s) then table.length - 1
    // is 1111.. with n 1's.
    // In other words this masks on the last n bits in the hash
-    h & (table.length - 1)
+    hash & (table.length - 1)
  }

  /**
@@ -180,20 +176,21 @@ final class WeakHashSet[A <: AnyRef](val initialCapacity: Int, val loadFactor: D
        elem
      }

-      def linkedListLoop(entry: Entry[A]): A = entry match {
+      def linkedListLoop(entry: Entry[A], depth: Int): A = entry match {
        case null                    => add()
        case _                       => {
          val entryElem = entry.get
          if (elem.equals(entryElem)) entryElem
          else {
-            val result = linkedListLoop(entry.tail)
-            result.getClass
+            val result = linkedListLoop(entry.tail, depth + 1)
+            if (depth > 0)
+              result.getClass
            result
          }
        }
      }

-      linkedListLoop(oldHead)
+      linkedListLoop(oldHead, 0)
    }
  }