Scaladoc: Reducing the memory footprint

 - diagrams are not stored because they create many TypeEntities, nodes
and edges -- now they are created on demand, so make sure you don't
demand them twice!
 - eliminated the type entity cache, which was nearly useless (6s gain)
but was preventing the GC from eliminating TypeEntities
 - an unsuccessful attempt at reducing the tons of :: garbage we're
generating - there's 200MB-250MB of ::s during a typical 'ant docs.lib'

5 files changed, 31 insertions, 37 deletions

diff --git a/src/compiler/scala/tools/nsc/doc/DocFactory.scala b/src/compiler/scala/tools/nsc/doc/DocFactory.scala
index 9fccc57e44..27a03d5381 100644
--- a/src/compiler/scala/tools/nsc/doc/DocFactory.scala
+++ b/src/compiler/scala/tools/nsc/doc/DocFactory.scala
@@ -101,7 +101,6 @@ class DocFactory(val reporter: Reporter, val settings: doc.Settings) { processor
           println("no documentable class found in compilation units")
         None
     }
-
   }
 
   object NoCompilerRunException extends ControlThrowable { }
diff --git a/src/compiler/scala/tools/nsc/doc/html/page/Template.scala b/src/compiler/scala/tools/nsc/doc/html/page/Template.scala
index cfd50db99f..417bfcfb96 100644
--- a/src/compiler/scala/tools/nsc/doc/html/page/Template.scala
+++ b/src/compiler/scala/tools/nsc/doc/html/page/Template.scala
@@ -601,13 +601,13 @@ class Template(universe: doc.Universe, generator: DiagramGenerator, tpl: DocTemp
     }
 
     val typeHierarchy = if (s.docDiagrams.isSetByUser) mbr match {
-      case dtpl: DocTemplateEntity if isSelf && !isReduced && dtpl.inheritanceDiagram.isDefined =>
+      case dtpl: DocTemplateEntity if isSelf && !isReduced =>
         makeDiagramHtml(dtpl, dtpl.inheritanceDiagram, "Type Hierarchy", "inheritance-diagram")
       case _ => NodeSeq.Empty
     } else NodeSeq.Empty // diagrams not generated
 
     val contentHierarchy = if (s.docDiagrams.isSetByUser) mbr match {
-      case dtpl: DocTemplateEntity if isSelf && !isReduced && dtpl.contentDiagram.isDefined =>
+      case dtpl: DocTemplateEntity if isSelf && !isReduced =>
         makeDiagramHtml(dtpl, dtpl.contentDiagram, "Content Hierarchy", "content-diagram")
       case _ => NodeSeq.Empty
     } else NodeSeq.Empty // diagrams not generated
@@ -916,16 +916,18 @@ class Template(universe: doc.Universe, generator: DiagramGenerator, tpl: DocTemp
   }
 
   def makeDiagramHtml(tpl: DocTemplateEntity, diagram: Option[Diagram], description: String, id: String) = {
-    val s = universe.settings
-    val diagramSvg = generator.generate(diagram.get, tpl, this)
-    if (diagramSvg != NodeSeq.Empty) {
-      <div class="toggleContainer block diagram-container" id={ id + "-container"}>
-        <span class="toggle diagram-link">{ description }</span>
-        <a href="http://docs.scala-lang.org/overviews/scaladoc/usage.html#diagrams" target="_blank" class="diagram-help">Learn more about scaladoc diagrams</a>
-        <div class="diagram" id={ id }>{
-          diagramSvg
-        }</div>
-      </div>
+    if (diagram.isDefined) {
+      val s = universe.settings
+      val diagramSvg = generator.generate(diagram.get, tpl, this)
+      if (diagramSvg != NodeSeq.Empty) {
+        <div class="toggleContainer block diagram-container" id={ id + "-container"}>
+          <span class="toggle diagram-link">{ description }</span>
+          <a href="http://docs.scala-lang.org/overviews/scaladoc/usage.html#diagrams" target="_blank" class="diagram-help">Learn more about scaladoc diagrams</a>
+          <div class="diagram" id={ id }>{
+            diagramSvg
+          }</div>
+        </div>
+      } else NodeSeq.Empty
     } else NodeSeq.Empty
   }
 }
diff --git a/src/compiler/scala/tools/nsc/doc/model/ModelFactory.scala b/src/compiler/scala/tools/nsc/doc/model/ModelFactory.scala
index 2642551aa8..d3d229d848 100644
--- a/src/compiler/scala/tools/nsc/doc/model/ModelFactory.scala
+++ b/src/compiler/scala/tools/nsc/doc/model/ModelFactory.scala
@@ -449,9 +449,9 @@ class ModelFactory(val global: Global, val settings: doc.Settings) {
       case _ => None
     }
 
-    // We make the diagram a lazy val, since we're not sure we'll include the diagrams in the page
-    lazy val inheritanceDiagram = makeInheritanceDiagram(this)
-    lazy val contentDiagram = makeContentDiagram(this)
+    // These are generated on-demand, make sure you don't call them more than once
+    def inheritanceDiagram = makeInheritanceDiagram(this)
+    def contentDiagram = makeContentDiagram(this)
   }
 
   abstract class PackageImpl(sym: Symbol, inTpl: PackageImpl) extends DocTemplateImpl(sym, inTpl) with Package {
diff --git a/src/compiler/scala/tools/nsc/doc/model/ModelFactoryTypeSupport.scala b/src/compiler/scala/tools/nsc/doc/model/ModelFactoryTypeSupport.scala
index 5efae3257c..d2a26d1309 100644
--- a/src/compiler/scala/tools/nsc/doc/model/ModelFactoryTypeSupport.scala
+++ b/src/compiler/scala/tools/nsc/doc/model/ModelFactoryTypeSupport.scala
@@ -30,8 +30,7 @@ trait ModelFactoryTypeSupport {
   import definitions.{ ObjectClass, NothingClass, AnyClass, AnyValClass, AnyRefClass }
   import rootMirror.{ RootPackage, RootClass, EmptyPackage }
 
-  protected var typeCache = new mutable.LinkedHashMap[(Type, TemplateImpl), TypeEntity]
-  protected var typeCacheNoPrefix = new mutable.LinkedHashMap[Type, TypeEntity]
+  protected var typeCache = new mutable.LinkedHashMap[Type, TypeEntity]
 
   /** */
   def makeType(aType: Type, inTpl: TemplateImpl): TypeEntity = {
@@ -309,21 +308,16 @@ trait ModelFactoryTypeSupport {
 
     // SI-4360: Entity caching depends on both the type AND the template it's in, as the prefixes might change for the
     // same type based on the template the type is shown in.
-    val cached =
-      if (!settings.docNoPrefixes.value)
-        typeCache.get((aType, inTpl))
-      else
-        typeCacheNoPrefix.get(aType)
-
-    cached match {
-      case Some(typeEntity) => typeEntity
-      case None =>
-        val typeEntity = createTypeEntity
-        if (!settings.docNoPrefixes.value)
-          typeCache += (aType, inTpl) -> typeEntity
-        else
-          typeCacheNoPrefix += aType -> typeEntity
-        typeEntity
-    }
+    if (settings.docNoPrefixes.value) {
+      val cached = typeCache.get(aType)
+      cached match {
+        case Some(typeEntity) =>
+          typeEntity
+        case None =>
+          val typeEntity = createTypeEntity
+          typeCache += aType -> typeEntity
+          typeEntity
+      }
+    } else createTypeEntity
   }
 }
\ No newline at end of file
diff --git a/src/compiler/scala/tools/nsc/doc/model/diagram/DiagramFactory.scala b/src/compiler/scala/tools/nsc/doc/model/diagram/DiagramFactory.scala
index d0b363854c..9b56509623 100644
--- a/src/compiler/scala/tools/nsc/doc/model/diagram/DiagramFactory.scala
+++ b/src/compiler/scala/tools/nsc/doc/model/diagram/DiagramFactory.scala
@@ -61,9 +61,8 @@ trait DiagramFactory extends DiagramDirectiveParser {
 
         // subclasses
         var subclasses: List[Node] =
-          tpl.directSubClasses.flatMap {
-            case d: TemplateImpl if !classExcluded(d) => List(NormalNode(makeType(d.sym.tpe, tpl), Some(d))())
-            case _ => Nil
+          tpl.directSubClasses.collect {
+            case d: TemplateImpl if !classExcluded(d) => NormalNode(makeType(d.sym.tpe, tpl), Some(d))()
           }.sortBy(_.tpl.get.name)(implicitly[Ordering[String]].reverse)
 
         // outgoing implicit coversions