Attempts to improve inlining behavior for map, flatMap.

Reduced method size of map/flatMap to under 35 bytes to make them
inlinable. Also specialized filterNot code so that it does not create
a second closure. Finally, avoided default argument for sizeHint to
reduce size of methods calling it.

1 files changed, 19 insertions, 1 deletions

diff --git a/src/library/scala/collection/mutable/Builder.scala b/src/library/scala/collection/mutable/Builder.scala
index bbf4f5889d..b6887df61e 100644
--- a/src/library/scala/collection/mutable/Builder.scala
+++ b/src/library/scala/collection/mutable/Builder.scala
@@ -62,9 +62,27 @@ trait Builder[-Elem, +To] extends Growable[Elem] {
    *  wrong, i.e. a different number of elements is added.
    *
    *  @param coll  the collection which serves as a hint for the result's size.
+   */
+  def sizeHint(coll: TraversableLike[_, _]) {
+    if (coll.isInstanceOf[collection.IndexedSeqLike[_,_]]) {
+      sizeHint(coll.size)
+    }
+  }
+
+  /** Gives a hint that one expects the `result` of this builder
+   *  to have the same size as the given collection, plus some delta. This will
+   *  provide a hint only if the collection is known to have a cheap
+   *  `size` method. Currently this is assumed to be the case if and only if
+   *  the collection is of type `IndexedSeqLike`.
+   *  Some builder classes
+   *  will optimize their representation based on the hint. However,
+   *  builder implementations are still required to work correctly even if the hint is
+   *  wrong, i.e. a different number of elements is added.
+   *
+   *  @param coll  the collection which serves as a hint for the result's size.
    *  @param delta a correction to add to the `coll.size` to produce the size hint.
    */
-  def sizeHint(coll: TraversableLike[_, _], delta: Int = 0) {
+  def sizeHint(coll: TraversableLike[_, _], delta: Int) {
     if (coll.isInstanceOf[collection.IndexedSeqLike[_,_]]) {
       sizeHint(coll.size + delta)
     }