Break names out of the cake

Allow names to be shared

adapted from retronym#43

adapted from

Author: mkeskells

src/compiler/scala/tools/nsc/Global.scala

@@ -41,6 +41,8 @@ import scala.tools.nsc.classpath._
 import scala.tools.nsc.profile.Profiler
 import scala.util.control.NonFatal
 import java.io.Closeable
+import java.util.concurrent.atomic.AtomicReference
+
 import scala.annotation.tailrec
 
 class Global(var currentSettings: Settings, reporter0: LegacyReporter)
@@ -1731,6 +1733,17 @@ class Global(var currentSettings: Settings, reporter0: LegacyReporter)
     perRunCaches.clearAll()
     closeableRegistry.close()
   }
+  override protected def newNameTable: NameTable = {
+    if (currentSettings.YcacheNameTable) {
+      var shared: NameTable = null
+      do {
+        shared = Global.nameTableCache.get
+        if (shared == null) Global.nameTableCache.compareAndSet(null, new scala.reflect.internal.NameTable)
+      } while (shared == null)
+      shared
+    }
+    else super.newNameTable
+  }
 }
 
 object Global {
@@ -1743,4 +1756,5 @@ object Global {
     override def keepsTypeParams = false
     def run(): Unit = { throw new Error("InitPhase.run") }
   }
+  private val nameTableCache = new AtomicReference[scala.reflect.internal.NameTable]
 }

src/compiler/scala/tools/nsc/settings/ScalaSettings.scala

@@ -251,6 +251,7 @@ trait ScalaSettings extends AbsScalaSettings
   val YcachePluginClassLoader  = CachePolicy.setting("plugin", "compiler plugins")
   val YcacheMacroClassLoader   = CachePolicy.setting("macro", "macros")
   val YmacroClasspath = PathSetting       ("-Ymacro-classpath", "The classpath used to reflectively load macro implementations, default is the compilation classpath.", "")
+  val YcacheNameTable = BooleanSetting    ("-Ycache-name-table", "Share a single name table for concurrently running instances of the compiler")
 
   val exposeEmptyPackage = BooleanSetting ("-Yexpose-empty-package", "Internal only: expose the empty package.").internalOnly()
   val Ydelambdafy        = ChoiceSetting  ("-Ydelambdafy", "strategy", "Strategy used for translating lambdas into JVM code.", List("inline", "method"), "method")

src/reflect/scala/reflect/api/Names.scala

@@ -55,30 +55,82 @@ trait Names {
 //  @deprecated("use explicit `TypeName(s)` instead", "2.11.0")
 //  implicit def stringToTypeName(s: String): TypeName = TypeName(s)
 
+  type NameTable <: NameTableApi
+
+  val nameTable: NameTable
+
   /** The abstract type of names.
    *  @group Names
    */
-  type Name >: Null <: AnyRef with NameApi
+  type Name >: Null <: AnyRef with nameTable.NameApi
 
   /** The abstract type of names representing terms.
    *  @group Names
    */
-  type TypeName >: Null <: TypeNameApi with Name
+  type TypeName >: Null <: nameTable.TypeNameApi with Name
+  /** The abstract type of names representing types.
+    *  @group Names
+    */
+  type TermName >: Null <: nameTable.TermNameApi with Name
+
+  /** The API of Name instances.
+    *  @group API
+    */
+  type NameApi <: nameTable.NameApi
+
+  /** Create a new term name.
+    *  @group Names
+    */
+  @deprecated("use TermName instead", "2.11.0")
+  def newTermName(s: String): TermName
+
+  /** Creates a new type name.
+    *  @group Names
+    */
+  @deprecated("use TypeName instead", "2.11.0")
+  def newTypeName(s: String): TypeName
+
+  /** The constructor/extractor for `TermName` instances.
+    *  @group Extractors
+    */
+  val TermName: TermNameExtractor
+
+  /** An extractor class to create and pattern match with syntax `TermName(s)`.
+    *  @group Extractors
+    */
+  abstract class TermNameExtractor {
+    def apply(s: String): TermName
+    def unapply(name: TermName): Option[String]
+  }
+
+  /** The constructor/extractor for `TypeName` instances.
+    *  @group Extractors
+    */
+  val TypeName: TypeNameExtractor
+
+  /** An extractor class to create and pattern match with syntax `TypeName(s)`.
+    *  @group Extractors
+    */
+  abstract class TypeNameExtractor {
+    def apply(s: String): TypeName
+    def unapply(name: TypeName): Option[String]
+  }
+}
+
+abstract class NameTableApi {
+  /** The abstract type of names.
+    *  @group Names
+    */
+ type Name >: Null <: AnyRef with NameApi
+
+ type TypeName >: Null <: TypeNameApi with Name
 
-  /** Has no special methods. Is here to provides erased identity for `TypeName`.
-   *  @group API
-   */
-  trait TypeNameApi
 
   /** The abstract type of names representing types.
    *  @group Names
    */
   type TermName >: Null <: TermNameApi with Name
 
-  /** Has no special methods. Is here to provides erased identity for `TermName`.
-   *  @group API
-   */
-  trait TermNameApi
 
   /** The API of Name instances.
    *  @group API
@@ -116,6 +168,15 @@ trait Names {
      */
     def encodedName: Name
   }
+  /** Has no special methods. Is here to provides erased identity for `TypeName`.
+    *  @group API
+    */
+  trait TypeNameApi extends NameApi
+  /** Has no special methods. Is here to provides erased identity for `TermName`.
+    *  @group API
+    */
+  trait TermNameApi extends NameApi
+
 
   /** Create a new term name.
    *  @group Names
@@ -129,29 +190,4 @@ trait Names {
   @deprecated("use TypeName instead", "2.11.0")
   def newTypeName(s: String): TypeName
 
-  /** The constructor/extractor for `TermName` instances.
-   *  @group Extractors
-   */
-  val TermName: TermNameExtractor
-
-  /** An extractor class to create and pattern match with syntax `TermName(s)`.
-   *  @group Extractors
-   */
-  abstract class TermNameExtractor {
-    def apply(s: String): TermName
-    def unapply(name: TermName): Option[String]
-  }
-
-  /** The constructor/extractor for `TypeName` instances.
-   *  @group Extractors
-   */
-  val TypeName: TypeNameExtractor
-
-  /** An extractor class to create and pattern match with syntax `TypeName(s)`.
-   *  @group Extractors
-   */
-  abstract class TypeNameExtractor {
-    def apply(s: String): TypeName
-    def unapply(name: TypeName): Option[String]
-  }
 }

src/reflect/scala/reflect/internal/Names.scala

@@ -16,30 +16,51 @@ package internal
 
 import java.util.concurrent.ConcurrentHashMap
 
+import scala.reflect.api.NameTableApi
+
 trait Names extends api.Names {
-  def nameTableSize: Int = cache.size
+  type NameTable = scala.reflect.internal.NameTable
+  override val nameTable: NameTable = newNameTable
 
-  override final type Name =  AName
-  override final type TypeName = TermNameImpl#TypeNameImpl
-  override final type TermName = TermNameImpl
+  protected def newNameTable: NameTable = new NameTable
+
+  def nameTableSize: Int = nameTable.nameTableSize
+  override final type Name = nameTable.AName
+  override final type TypeName = nameTable.TypeNameImpl
+  override final type TermName = nameTable.TermNameImpl
 
   implicit final val NameTag = ClassTag[Name](classOf[Name])
   implicit final val TermNameTag = ClassTag[TermName](classOf[TermName])
   implicit final val TypeNameTag = ClassTag[TypeName](classOf[TypeName])
 
-
-  override object TermName extends TermNameExtractor {
-    @inline override def apply(s: String): TermName = newTermName(s)
-    override def unapply(name: TermName): Option[String] = Some(name.rawString)
+  override final def newTypeName(value: String): TypeName = nameTable.newTypeName(value)
+  override final def newTermName(value: String): TermName = nameTable.newTermName(value)
+  object TermName extends TermNameExtractor {
+    def apply(s: String) = newTermName(s)
+    def unapply(name: TermName): Option[String] = Some(name.toString)
   }
-  override object TypeName extends TypeNameExtractor {
-    @inline override def apply(s: String): TypeName = newTypeName(s)
-    override def unapply(name: TypeName): Option[String] = Some(name.rawString)
+  object TypeName extends TypeNameExtractor {
+    def apply(s: String) = newTypeName(s)
+    def unapply(name: TypeName): Option[String] = Some(name.toString)
   }
-  override final def newTypeName(value: String): TypeName = newTermName(value).companionName
+  //deprecated stuff
+  @deprecated
+  @inline final def newTermNameCached(s: String): TermName = newTermName(s)
+
+  @deprecated
+  @inline final def newTypeNameCached(s: String): TypeName = newTypeName(s)
+}
+class NameTable extends NameTableApi {
+  override final type Name = AName
+  override final type TypeName = TypeNameImpl
+  override final type TermName = TermNameImpl
+
+  def nameTableSize: Int = cache.size
+
+  private[this] final val cache = new ConcurrentHashMap[String, TermNameImpl](1000, 0.75F, 1)
 
-  override final def newTermName(value: String): TermName = {
-  //TODO consider a better structure to use than a CHM
+  override final def newTermName(value: String): TermNameImpl = {
+    //TODO consider a better structure to use than a CHM
     var res = cache.get(value)
     if (res eq null) {
       val next = new TermNameImpl(value)
@@ -50,25 +71,22 @@ trait Names extends api.Names {
     res
     //same as cache.computeIfAbsent(value, new NameHolder(_)) but faster
   }
-  private[this] final val cache = new ConcurrentHashMap[String, TermName](1000, 0.75F, 1)
-  //deprecated stuff
-  @deprecated @inline final def newTermNameCached(s: String): TermName = newTermName(s)
-  @deprecated @inline final def newTypeNameCached(s: String): TypeName = newTypeName(s)
+  final def newTypeName(value:String): TypeName = newTermName(value).companionName
 
   abstract sealed class AName extends NameApi with CharSequence {
     type ThisNameType <: AName
     @inline override final def length(): Int = value.length
     override final def subSequence(start: Int, end: Int): CharSequence = value.subSequence(start, end)
     override def decoded: String = decodedName.toString
     override def encoded: String = encodedName.toString
-    @inline private[Names] def rawString = value
-    override def decodedName: ThisNameType
-    override def encodedName: ThisNameType
+    @inline private[NameTable] def rawString = value
+    def decodedName: ThisNameType
+    def encodedName: ThisNameType
 
     //non API methods
     protected def value: String
 
-    def companionName: Name
+    def companionName: AName
 
     /** Return the subname with characters from from to to-1. */
     def subName(from: Int, to: Int): ThisNameType =
@@ -250,12 +268,12 @@ trait Names extends api.Names {
   }
   final class TermNameImpl(override val toString: String) extends AName with TermNameApi {
     type ThisNameType = TermName
+
     override def isTermName = true
     override def isTypeName = false
 
     override protected def value: String = toString
 
-
     override def toTermName: TermName = this
     override def toTypeName: TypeName = typeName
 
@@ -269,7 +287,7 @@ trait Names extends api.Names {
     def identifier = identifier_ & 0x80FF
     def markAsIdentifier(java: Boolean, newIdentifier: Int) {
       require((identifier.toShort & 0x80FF) == identifier.toShort)
-      val flag =  (if (java) 0x1000 else 0x2000).toShort
+      val flag = (if (java) 0x1000 else 0x2000).toShort
       if (identifier_ == 0) {
         //first call
         this.identifier_ = (newIdentifier | flag).toShort
@@ -290,31 +308,30 @@ trait Names extends api.Names {
       else this
     }
     override lazy final val encodedName: TermName = {
-        val res = NameTransformer.encode(value)
-        if (res == value) this else newName(res)
-      }
-
-    private lazy val typeName:TypeName = new TypeNameImpl
+      val res = NameTransformer.encode(value)
+      if (res == value) this else newName(res)
+    }
 
+    private[NameTable] lazy val typeName: TypeNameImpl = new TypeNameImpl(this)
 
-    final class TypeNameImpl extends AName with TypeNameApi {
-      type ThisNameType = TypeName
-      override def isTermName = false
-      override def isTypeName = true
-      override def decodedName: TypeName = TermNameImpl.this.decodedName.typeName
-      override def encodedName: TypeName  = TermNameImpl.this.encodedName.typeName
+  }
+  final class TypeNameImpl(term: TermNameImpl) extends AName with TypeNameApi {
+    type ThisNameType = TypeName
+    override def isTermName = false
+    override def isTypeName = true
+    override def decodedName: TypeName = term.decodedName.typeName
+    override def encodedName: TypeName  = term.encodedName.typeName
 
 
-      override protected def value: String = TermNameImpl.this.toString
-      override def toString: String = TermNameImpl.this.toString
+    override protected def value: String = term.toString
+    override def toString: String = term.toString
 
-      override def toTermName: TermName = TermNameImpl.this
-      override def toTypeName: TypeName = this
+    override def toTermName: TermName = term
+    override def toTypeName: TypeName = this
 
-      override def companionName = TermNameImpl.this
-      override def newName(str: String) = newTypeName(str)
-      override def nameKind = "type"
-      def debugString = decoded + "!"
-    }
+    override def companionName = term
+    override def newName(str: String) = newTypeName(str)
+    override def nameKind = "type"
+    def debugString = decoded + "!"
   }
 }

test/files/run/reflection-names.check

@@ -1,4 +1,4 @@
 (java.lang.String,bc)
-(scala.reflect.internal.Names$TermName_R,bc)
-(scala.reflect.internal.Names$TypeName_R,bc)
-(scala.reflect.internal.Names$TypeName_R,bc)
+(scala.reflect.internal.NameTable$TermNameImpl,bc)
+(scala.reflect.internal.NameTable$TypeNameImpl,bc)
+(scala.reflect.internal.NameTable$TypeNameImpl,bc)