Various caches for incremental compilation.

dart/sdk/lib/_internal/compiler/implementation/world.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart2js;
 
 class World {
   final Compiler compiler;
   final FunctionSet allFunctions;
   final Set<Element> functionsCalledInLoop = new Set<Element>();
@@ skipping 14 matching lines @@
   final Map<ClassElement, Set<ClassElement>> _supertypes =
       new Map<ClassElement, Set<ClassElement>>();
 
   final Set<Element> sideEffectsFreeElements = new Set<Element>();
 
   final Set<Element> elementsThatCannotThrow = new Set<Element>();
 
   final Set<Element> functionsThatMightBePassedToApply =
       new Set<FunctionElement>();
 
+  final Set<Element> alreadyPopulated = new Set<Element>.identity();
+
   Set<ClassElement> subclassesOf(ClassElement cls) {
     return _subclasses[cls.declaration];
   }
 
   Set<ClassElement> subtypesOf(ClassElement cls) {
     return _subtypes[cls.declaration];
   }
 
   Set<ClassElement> supertypesOf(ClassElement cls) {
     return _supertypes[cls.declaration];
   }
 
   Set<ClassElement> typesImplementedBySubclassesOf(ClassElement cls) {
     return _typesImplementedBySubclasses[cls.declaration];
   }
 
   bool hasSubclasses(ClassElement cls) {
     Set<ClassElement> subclasses = compiler.world.subclassesOf(cls);
     return subclasses != null && !subclasses.isEmpty;
   }
 
   World(Compiler compiler)
       : allFunctions = new FunctionSet(compiler),
         this.compiler = compiler;
 
   void populate() {
     void addSubtypes(ClassElement cls) {
+      if (compiler.hasIncrementalSupport && !alreadyPopulated.add(cls)) {
+        return;
+      }
       assert(cls.isDeclaration);
       if (cls.resolutionState != STATE_DONE) {
         compiler.internalError(cls, 'Class "${cls.name}" is not resolved.');
       }
 
       for (DartType type in cls.allSupertypes) {
         Set<Element> supertypesOfClass =
             _supertypes.putIfAbsent(cls, () => new Set<ClassElement>());
         Set<Element> subtypesOfSupertype =
             _subtypes.putIfAbsent(type.element, () => new Set<ClassElement>());
@@ skipping 220 matching lines @@
     // method of function classes that were generated for function
     // expressions. In such a case, we have to look at the original
     // function expressions's element.
     // TODO(herhut): Generate classes for function expressions earlier.
     if (element is closureMapping.SynthesizedCallMethodElementX) {
       return getMightBePassedToApply(element.expression);
     }
     return functionsThatMightBePassedToApply.contains(element);
   }
 }