Improved runtime speed for Vector, restoring previous performance.

All calls to Platform.arraycopy were rewritten as java.lang.System.arraycopy to reduce the work that the JIT compiler has to do to produce optimized bytecode that avoids zeroing just-allocated arrays that are about to be copied over.

(Tested with -XX:-ReduceBulkZeroing as suggested by retronym.)

1 files changed, 4 insertions, 5 deletions

diff --git a/src/library/scala/collection/immutable/Vector.scala b/src/library/scala/collection/immutable/Vector.scala
index a162fdaaf8..d9d925705f 100644
--- a/src/library/scala/collection/immutable/Vector.scala
+++ b/src/library/scala/collection/immutable/Vector.scala
@@ -11,7 +11,6 @@ package collection
 package immutable
 
 import scala.annotation.unchecked.uncheckedVariance
-import scala.compat.Platform
 import scala.collection.generic._
 import scala.collection.mutable.{Builder, ReusableBuilder}
 import scala.collection.parallel.immutable.ParVector
@@ -478,12 +477,12 @@ override def companion: GenericCompanion[Vector] = Vector
 //    if (array eq null)
 //      println("OUCH!!! " + right + "/" + depth + "/"+startIndex + "/" + endIndex + "/" + focus)
     val a2 = new Array[AnyRef](array.length)
-    Platform.arraycopy(array, 0, a2, 0, right)
+    java.lang.System.arraycopy(array, 0, a2, 0, right)
     a2
   }
   private def copyRight(array: Array[AnyRef], left: Int): Array[AnyRef] = {
     val a2 = new Array[AnyRef](array.length)
-    Platform.arraycopy(array, left, a2, left, a2.length - left)
+    java.lang.System.arraycopy(array, left, a2, left, a2.length - left)
     a2
   }
 
@@ -955,7 +954,7 @@ private[immutable] trait VectorPointer[T] {
 
     private[immutable] final def copyOf(a: Array[AnyRef]) = {
       val b = new Array[AnyRef](a.length)
-      Platform.arraycopy(a, 0, b, 0, a.length)
+      java.lang.System.arraycopy(a, 0, b, 0, a.length)
       b
     }
 
@@ -1119,7 +1118,7 @@ private[immutable] trait VectorPointer[T] {
 
     private[immutable] final def copyRange(array: Array[AnyRef], oldLeft: Int, newLeft: Int) = {
       val elems = new Array[AnyRef](32)
-      Platform.arraycopy(array, oldLeft, elems, newLeft, 32 - math.max(newLeft,oldLeft))
+      java.lang.System.arraycopy(array, oldLeft, elems, newLeft, 32 - math.max(newLeft,oldLeft))
       elems
     }