Misc performance improvements by eliminating stupid allocations

- Avoid closure creation in Position.
- Avoid creating debug string in SymDenotations
- Avoid creating Flag translation tables in pickle buffers

5 files changed, 25 insertions, 21 deletions

diff --git a/src/dotty/tools/dotc/core/SymDenotations.scala b/src/dotty/tools/dotc/core/SymDenotations.scala
index 7bd64a6c2..4ff6e629e 100644
--- a/src/dotty/tools/dotc/core/SymDenotations.scala
+++ b/src/dotty/tools/dotc/core/SymDenotations.scala
@@ -709,7 +709,7 @@ object SymDenotations {
       s"$kindString $name"
     }
 
-    val debugString = toString+"#"+symbol.id // !!! DEBUG
+    def debugString = toString+"#"+symbol.id // !!! DEBUG
 
     // ----- copies ------------------------------------------------------
 
diff --git a/src/dotty/tools/dotc/core/pickling/PickleBuffer.scala b/src/dotty/tools/dotc/core/pickling/PickleBuffer.scala
index b44d7f292..72007758c 100644
--- a/src/dotty/tools/dotc/core/pickling/PickleBuffer.scala
+++ b/src/dotty/tools/dotc/core/pickling/PickleBuffer.scala
@@ -166,6 +166,27 @@ class PickleBuffer(data: Array[Byte], from: Int, to: Int) {
   def times[T](n: Int, op: ()=>T): List[T] =
     if (n == 0) List() else op() :: times(n-1, op)
 
+  /** Pickle = majorVersion_Nat minorVersion_Nat nbEntries_Nat {Entry}
+   *  Entry  = type_Nat length_Nat [actual entries]
+   *
+   *  Assumes that the ..Version_Nat are already consumed.
+   *
+   *  @return an array mapping entry numbers to locations in
+   *  the byte array where the entries start.
+   */
+  def createIndex: Array[Int] = {
+    val index = new Array[Int](readNat()) // nbEntries_Nat
+    for (i <- 0 until index.length) {
+      index(i) = readIndex
+      readByte() // skip type_Nat
+      readIndex = readNat() + readIndex // read length_Nat, jump to next entry
+    }
+    index
+  }
+}
+
+object PickleBuffer {
+
   private final val ScalaFlagEnd = 48
   private final val ChunkBits = 8
   private final val ChunkSize = 1 << ChunkBits
@@ -261,24 +282,6 @@ class PickleBuffer(data: Array[Byte], from: Int, to: Int) {
     (chunkMap(termMap), chunkMap(typeMap))
   }
 
-  /** Pickle = majorVersion_Nat minorVersion_Nat nbEntries_Nat {Entry}
-   *  Entry  = type_Nat length_Nat [actual entries]
-   *
-   *  Assumes that the ..Version_Nat are already consumed.
-   *
-   *  @return an array mapping entry numbers to locations in
-   *  the byte array where the entries start.
-   */
-  def createIndex: Array[Int] = {
-    val index = new Array[Int](readNat()) // nbEntries_Nat
-    for (i <- 0 until index.length) {
-      index(i) = readIndex
-      readByte() // skip type_Nat
-      readIndex = readNat() + readIndex // read length_Nat, jump to next entry
-    }
-    index
-  }
-
   def unpickleScalaFlags(sflags: Long, isType: Boolean): FlagSet = {
     val map: FlagMap = if (isType) scalaTypeFlagMap else scalaTermFlagMap
     val shift = ChunkBits
diff --git a/src/dotty/tools/dotc/core/pickling/UnPickler.scala b/src/dotty/tools/dotc/core/pickling/UnPickler.scala
index 544a2ebdb..84b300a2a 100644
--- a/src/dotty/tools/dotc/core/pickling/UnPickler.scala
+++ b/src/dotty/tools/dotc/core/pickling/UnPickler.scala
@@ -15,6 +15,7 @@ import printing.Texts._
 import printing.Printer
 import io.AbstractFile
 import util.common._
+import PickleBuffer._
 import scala.reflect.internal.pickling.PickleFormat._
 import Decorators._
 import scala.collection.{ mutable, immutable }
diff --git a/src/dotty/tools/dotc/util/Positions.scala b/src/dotty/tools/dotc/util/Positions.scala
index 21ee788ca..293bb4a4c 100644
--- a/src/dotty/tools/dotc/util/Positions.scala
+++ b/src/dotty/tools/dotc/util/Positions.scala
@@ -125,7 +125,7 @@ object Positions {
   def Position(start: Int, end: Int, point: Int): Position = {
     val pointDelta = (point - start) max 0
     val pos = fromOffsets(start, end, if (pointDelta >= SyntheticPointDelta) 0 else pointDelta)
-    assert(pos.isSourceDerived, pos+" "+SyntheticPointDelta)
+    assert(pos.isSourceDerived)
     pos
   }
 
diff --git a/src/dotty/tools/dotc/util/ShowPickled.scala b/src/dotty/tools/dotc/util/ShowPickled.scala
index 92ce44bc6..1a9da23d5 100644
--- a/src/dotty/tools/dotc/util/ShowPickled.scala
+++ b/src/dotty/tools/dotc/util/ShowPickled.scala
@@ -149,7 +149,7 @@ object ShowPickled {
             idx + "(" + s + ")"
           }
         )
-        val flagString = buf.unpickleScalaFlags(pflags, isType).toString
+        val flagString = PickleBuffer.unpickleScalaFlags(pflags, isType).toString
         out.print(" %s[%s]".format(toHexString(pflags), flagString))
       }