Attempt #1 to optimize findMember

Keeps fingerprints in scopes which are bitsets telling you what the last 6 bits of each hashcode of the names stored in the scope are. findMember will avoid looking in a scope if inferprints do not match.

Author: odersky

src/reflect/scala/reflect/internal/Scopes.scala

@@ -42,6 +42,11 @@ trait Scopes extends api.Scopes { self: SymbolTable =>
    *  SynchronizedScope as mixin.
    */
   class Scope protected[Scopes] (initElems: ScopeEntry = null) extends Iterable[Symbol] {
+    
+    /** A bitset containing the last 6 bits of the start value of every name 
+     *  stored in this scope.
+     */
+    var fingerPrints: Long = 0L
 
     protected[Scopes] def this(base: Scope) = {
       this(base.elems)
@@ -95,7 +100,7 @@ trait Scopes extends api.Scopes { self: SymbolTable =>
      *
      *  @param e ...
      */
-    protected def enter(e: ScopeEntry) {
+    protected def enterEntry(e: ScopeEntry) {
       elemsCache = null
       if (hashtable ne null)
         enterInHash(e)
@@ -113,7 +118,11 @@ trait Scopes extends api.Scopes { self: SymbolTable =>
      *
      *  @param sym ...
      */
-    def enter[T <: Symbol](sym: T): T = { enter(newScopeEntry(sym, this)); sym }
+    def enter[T <: Symbol](sym: T): T = { 
+      fingerPrints |= (1L << sym.name.start)
+      enterEntry(newScopeEntry(sym, this)) 
+      sym 
+    }
 
     /** enter a symbol, asserting that no symbol with same name exists in scope
      *
@@ -344,7 +353,7 @@ trait Scopes extends api.Scopes { self: SymbolTable =>
   /** The empty scope (immutable).
    */
   object EmptyScope extends Scope {
-    override def enter(e: ScopeEntry) {
+    override def enterEntry(e: ScopeEntry) {
       abort("EmptyScope.enter")
     }
   }

src/reflect/scala/reflect/internal/Types.scala

@@ -1045,14 +1045,17 @@ trait Types extends api.Types { self: SymbolTable =>
       var continue = true
       var self: Type = null
       var membertpe: Type = null
+      val fingerPrint: Long = (1L << name.start)
       while (continue) {
         continue = false
         val bcs0 = baseClasses
         var bcs = bcs0
         while (!bcs.isEmpty) {
           val decls = bcs.head.info.decls
           var entry =
-            if (name == nme.ANYNAME) decls.elems else decls.lookupEntry(name)
+            if (name == nme.ANYNAME) decls.elems 
+            else if ((fingerPrint & decls.fingerPrints) == 0) null
+            else decls.lookupEntry(name)
           while (entry ne null) {
             val sym = entry.sym
             if (sym hasAllFlags requiredFlags) {