Optimization: Don't result of addrOfTree in Some

Instead use NoAddr as a sentinel for None.

Author: odersky

compiler/src/dotty/tools/dotc/core/tasty/CommentPickler.scala

@@ -3,11 +3,11 @@ package dotty.tools.dotc.core.tasty
 import dotty.tools.dotc.ast.tpd
 import dotty.tools.dotc.core.Comments.{Comment, CommentsContext, ContextDocstrings}
 import dotty.tools.dotc.core.Contexts.Context
-import dotty.tools.dotc.core.tasty.TastyBuffer.Addr
+import dotty.tools.dotc.core.tasty.TastyBuffer.{Addr, NoAddr}
 
 import java.nio.charset.Charset
 
-class CommentPickler(pickler: TastyPickler, addrOfTree: tpd.Tree => Option[Addr])(implicit ctx: Context) {
+class CommentPickler(pickler: TastyPickler, addrOfTree: tpd.Tree => Addr)(implicit ctx: Context) {
   private[this] val buf = new TastyBuffer(5000)
   pickler.newSection("Comments", buf)
 
@@ -16,8 +16,8 @@ class CommentPickler(pickler: TastyPickler, addrOfTree: tpd.Tree => Option[Addr]
     new Traverser(ctx.docCtx.get).traverse(root)
   }
 
-  def pickleComment(addrOfTree: Option[Addr], comment: Option[Comment]): Unit = (addrOfTree, comment) match {
-    case (Some(addr), Some(cmt)) =>
+  def pickleComment(addr: Addr, comment: Option[Comment]): Unit = comment match {
+    case Some(cmt) if addr != NoAddr =>
       val bytes = cmt.raw.getBytes(Charset.forName("UTF-8"))
       val length = bytes.length
       buf.writeAddr(addr)

compiler/src/dotty/tools/dotc/core/tasty/PositionPickler.scala

@@ -14,7 +14,7 @@ import TastyBuffer._
 import util.Spans._
 import TastyFormat.SOURCE
 
-class PositionPickler(pickler: TastyPickler, addrOfTree: untpd.Tree => Option[Addr]) {
+class PositionPickler(pickler: TastyPickler, addrOfTree: untpd.Tree => Addr) {
   val buf: TastyBuffer = new TastyBuffer(5000)
   pickler.newSection("Positions", buf)
   import ast.tpd._
@@ -72,19 +72,18 @@ class PositionPickler(pickler: TastyPickler, addrOfTree: untpd.Tree => Option[Ad
     def traverse(x: Any, current: SourceFile): Unit = x match {
       case x: untpd.Tree =>
         if (x.span.exists) {
-          val sourceChange = x.source != current
-          val needsPos = x.span.toSynthetic != x.envelope(x.source) || alwaysNeedsPos(x)
-          addrOfTree(x) match {
-            case Some(addr)
-            if needsPos && !pickledIndices.contains(addr.index) || sourceChange =>
-                // we currently do not share trees when unpickling, so if one path to a tree contains
-                // a source change while another does not, we have to record the position of the tree twice
-                // in order not to miss the source change. Test case is t3232a.scala.
-              //println(i"pickling $x with $span at $addr")
+          val addr = addrOfTree(x)
+          if (addr != NoAddr) {
+            if (x.source != current) {
+              // we currently do not share trees when unpickling, so if one path to a tree contains
+              // a source change while another does not, we have to record the position of the tree twice
+              // in order not to miss the source change. Test case is t3232a.scala.
+              pickleDeltas(addr.index, x.span)
+              pickleSource(x.source)
+            }
+            else if (!pickledIndices.contains(addr.index) &&
+                     (x.span.toSynthetic != x.envelope(x.source) || alwaysNeedsPos(x)))
               pickleDeltas(addr.index, x.span)
-              if (sourceChange) pickleSource(x.source)
-            case _ =>
-              //println(i"no address for $x")
           }
         }
         x match {

compiler/src/dotty/tools/dotc/core/tasty/TastyPickler.scala

@@ -67,7 +67,7 @@ class TastyPickler(val rootCls: ClassSymbol) {
    *  Note that trees are looked up by reference equality,
    *  so one can reliably use this function only directly after `pickler`.
    */
-  var addrOfTree: tpd.Tree => Option[Addr] = (_ => None)
+  var addrOfTree: tpd.Tree => Addr = (_ => NoAddr)
 
   /**
    * Addresses in TASTY file of symbols, stored by pickling.

compiler/src/dotty/tools/dotc/core/tasty/TreeBuffer.scala

@@ -4,7 +4,7 @@ package core
 package tasty
 
 import util.Util.{bestFit, dble}
-import TastyBuffer.{Addr, AddrWidth}
+import TastyBuffer.{Addr, NoAddr, AddrWidth}
 import config.Printers.pickling
 import ast.untpd.Tree
 
@@ -25,9 +25,9 @@ class TreeBuffer extends TastyBuffer(50000) {
     case addr: Addr => addr
   }
 
-  def addrOfTree(tree: Tree): Option[Addr] = treeAddrs.get(tree) match {
-    case null => None
-    case addr: Addr => Some(addr)
+  def addrOfTree(tree: Tree): Addr = treeAddrs.get(tree) match {
+    case null => NoAddr
+    case addr: Addr => addr
   }
 
   private def offset(i: Int): Addr = Addr(offsets(i))