Introduce isAbstractlyInstantiated to avoid exact masks of abstract classes.

pkg/compiler/lib/src/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.
 
 library dart2js.world;
 
 import 'closure.dart' show SynthesizedCallMethodElementX;
 import 'common/backend_api.dart' show BackendClasses;
 import 'common.dart';
 import 'compiler.dart' show Compiler;
 import 'core_types.dart' show CoreClasses;
 import 'dart_types.dart';
 import 'elements/elements.dart'
     show
         ClassElement,
         Element,
         FunctionElement,
         MixinApplicationElement,
         TypedefElement,
         VariableElement;
 import 'js_backend/backend.dart' show JavaScriptBackend;
 import 'ordered_typeset.dart';
 import 'types/masks.dart' show CommonMasks, FlatTypeMask, TypeMask;
 import 'universe/class_set.dart';
 import 'universe/function_set.dart' show FunctionSet;
 import 'universe/selector.dart' show Selector;
 import 'universe/side_effects.dart' show SideEffects;
+import 'util/enumset.dart';
 import 'util/util.dart' show Link;
 
 /// Common superinterface for [OpenWorld] and [ClosedWorld].
 abstract class World {}
 
 /// The [ClosedWorld] represents the information known about a program when
 /// compiling with closed-world semantics.
 ///
 /// Given the entrypoint of an application, we can track what's reachable from
 /// it, what functions are called, what classes are allocated, which native
 /// JavaScript types are touched, what language features are used, and so on.
 /// This precise knowledge about what's live in the program is later used in
 /// optimizations and other compiler decisions during code generation.
 abstract class ClosedWorld implements World {
   /// Access to core classes used by the backend.
   BackendClasses get backendClasses;
 
   /// Access to core classes used in the Dart language.
   CoreClasses get coreClasses;
 
   /// Returns `true` if [cls] is either directly or indirectly instantiated.
   bool isInstantiated(ClassElement cls);
 
-  /// Returns `true` if [cls] is directly instantiated.
+  /// Returns `true` if [cls] is directly instantiated. This means that at
+  /// runtime instances of exactly [cls] are assumed to exist.
   bool isDirectlyInstantiated(ClassElement cls);
 
+  /// Returns `true` if [cls] is abstractly instantiated. This means that at
+  /// runtime instances of [cls] or unknown subclasses of [cls] are assumed to
+  /// exist.
+  ///
+  /// This is used to mark native and/or reflectable classes as instantiated.
+  /// For native classes we do not know the exact class that instantiates [cls]
+  /// so [cls] here represents the root of the subclasses. For reflectable
+  /// classes we need event abstract classes to be 'live' even though they
+  /// cannot themselves be instantiated.
+  bool isAbstractlyInstantiated(ClassElement cls);
+
+  /// Returns `true` if [cls] is either directly or abstractly instantiated.
+  ///
+  /// See [isDirectlyInstantiated] and [isAbstractlyInstantiated].
+  bool isRootInstantiated(ClassElement cls);
+
   /// Returns `true` if [cls] is indirectly instantiated, that is through a
   /// subclass.
   bool isIndirectlyInstantiated(ClassElement cls);
 
   /// Returns `true` if [cls] is abstract and thus can only be instantiated
   /// through subclasses.
   bool isAbstract(ClassElement cls);
 
   /// Returns `true` if [cls] is implemented by an instantiated class.
   bool isImplemented(ClassElement cls);
@@ skipping 322 matching lines @@
   }
 
   @override
   bool isDirectlyInstantiated(ClassElement cls) {
     assert(isClosed);
     ClassHierarchyNode node = _classHierarchyNodes[cls.declaration];
     return node != null && node.isDirectlyInstantiated;
   }
 
   @override
+  bool isAbstractlyInstantiated(ClassElement cls) {
+    assert(isClosed);
+    ClassHierarchyNode node = _classHierarchyNodes[cls.declaration];
+    return node != null && node.isAbstractlyInstantiated;
+  }
+
+  @override
+  bool isRootInstantiated(ClassElement cls) {
+    assert(isClosed);
+    ClassHierarchyNode node = _classHierarchyNodes[cls.declaration];
+    return node != null && node.isRootInstantiated;
+  }
+
+  @override
   bool isIndirectlyInstantiated(ClassElement cls) {
     assert(isClosed);
     ClassHierarchyNode node = _classHierarchyNodes[cls.declaration];
     return node != null && node.isIndirectlyInstantiated;
   }
 
   @override
   bool isAbstract(ClassElement cls) => cls.isAbstract;
 
   /// Returns `true` if [cls] is implemented by an instantiated class.
   bool isImplemented(ClassElement cls) {
     assert(isClosed);
     return _compiler.resolverWorld.isImplemented(cls);
   }
 
   /// Returns an iterable over the directly instantiated classes that extend
   /// [cls] possibly including [cls] itself, if it is live.
   Iterable<ClassElement> subclassesOf(ClassElement cls) {
     assert(isClosed);
     ClassHierarchyNode hierarchy = _classHierarchyNodes[cls.declaration];
     if (hierarchy == null) return const <ClassElement>[];
-    return hierarchy.subclassesByMask(ClassHierarchyNode.DIRECTLY_INSTANTIATED);
+    return hierarchy.subclassesByMask(ClassHierarchyNode.ROOT_INSTANTIATED);
   }
 
   /// Returns an iterable over the directly instantiated classes that extend
   /// [cls] _not_ including [cls] itself.
   Iterable<ClassElement> strictSubclassesOf(ClassElement cls) {
     assert(isClosed);
     ClassHierarchyNode subclasses = _classHierarchyNodes[cls.declaration];
     if (subclasses == null) return const <ClassElement>[];
-    return subclasses.subclassesByMask(ClassHierarchyNode.DIRECTLY_INSTANTIATED,
+    return subclasses.subclassesByMask(ClassHierarchyNode.ROOT_INSTANTIATED,
         strict: true);
   }
 
   /// Returns the number of live classes that extend [cls] _not_
   /// including [cls] itself.
   int strictSubclassCount(ClassElement cls) {
     assert(isClosed);
     ClassHierarchyNode subclasses = _classHierarchyNodes[cls.declaration];
     if (subclasses == null) return 0;
     return subclasses.instantiatedSubclassCount;
   }
 
   /// Applies [f] to each live class that extend [cls] _not_ including [cls]
   /// itself.
   void forEachStrictSubclassOf(
       ClassElement cls, IterationStep f(ClassElement cls)) {
     assert(isClosed);
     ClassHierarchyNode subclasses = _classHierarchyNodes[cls.declaration];
     if (subclasses == null) return;
-    subclasses.forEachSubclass(f, ClassHierarchyNode.DIRECTLY_INSTANTIATED,
+    subclasses.forEachSubclass(f, ClassHierarchyNode.ROOT_INSTANTIATED,
         strict: true);
   }
 
   /// Returns `true` if [predicate] applies to any live class that extend [cls]
   /// _not_ including [cls] itself.
   bool anyStrictSubclassOf(ClassElement cls, bool predicate(ClassElement cls)) {
     assert(isClosed);
     ClassHierarchyNode subclasses = _classHierarchyNodes[cls.declaration];
     if (subclasses == null) return false;
     return subclasses.anySubclass(
-        predicate, ClassHierarchyNode.DIRECTLY_INSTANTIATED,
+        predicate, ClassHierarchyNode.ROOT_INSTANTIATED,
         strict: true);
   }
 
   /// Returns an iterable over the directly instantiated that implement [cls]
   /// possibly including [cls] itself, if it is live.
   Iterable<ClassElement> subtypesOf(ClassElement cls) {
     assert(isClosed);
     ClassSet classSet = _classSets[cls.declaration];
     if (classSet == null) {
       return const <ClassElement>[];
     } else {
-      return classSet.subtypesByMask(ClassHierarchyNode.DIRECTLY_INSTANTIATED);
+      return classSet.subtypesByMask(ClassHierarchyNode.ROOT_INSTANTIATED);
     }
   }
 
   /// Returns an iterable over the directly instantiated that implement [cls]
   /// _not_ including [cls].
   Iterable<ClassElement> strictSubtypesOf(ClassElement cls) {
     assert(isClosed);
     ClassSet classSet = _classSets[cls.declaration];
     if (classSet == null) {
       return const <ClassElement>[];
     } else {
-      return classSet.subtypesByMask(ClassHierarchyNode.DIRECTLY_INSTANTIATED,
+      return classSet.subtypesByMask(ClassHierarchyNode.ROOT_INSTANTIATED,
           strict: true);
     }
   }
 
   /// Returns the number of live classes that implement [cls] _not_
   /// including [cls] itself.
   int strictSubtypeCount(ClassElement cls) {
     assert(isClosed);
     ClassSet classSet = _classSets[cls.declaration];
     if (classSet == null) return 0;
     return classSet.instantiatedSubtypeCount;
   }
 
   /// Applies [f] to each live class that implements [cls] _not_ including [cls]
   /// itself.
   void forEachStrictSubtypeOf(
       ClassElement cls, IterationStep f(ClassElement cls)) {
     assert(isClosed);
     ClassSet classSet = _classSets[cls.declaration];
     if (classSet == null) return;
-    classSet.forEachSubtype(f, ClassHierarchyNode.DIRECTLY_INSTANTIATED,
+    classSet.forEachSubtype(f, ClassHierarchyNode.ROOT_INSTANTIATED,
         strict: true);
   }
 
   /// Returns `true` if [predicate] applies to any live class that extend [cls]
   /// _not_ including [cls] itself.
   bool anyStrictSubtypeOf(ClassElement cls, bool predicate(ClassElement cls)) {
     assert(isClosed);
     ClassSet classSet = _classSets[cls.declaration];
     if (classSet == null) return false;
-    return classSet.anySubtype(
-        predicate, ClassHierarchyNode.DIRECTLY_INSTANTIATED,
+    return classSet.anySubtype(predicate, ClassHierarchyNode.ROOT_INSTANTIATED,
         strict: true);
   }
 
   /// Returns `true` if [a] and [b] have any known common subtypes.
   bool haveAnyCommonSubtypes(ClassElement a, ClassElement b) {
     assert(isClosed);
     ClassSet classSetA = _classSets[a.declaration];
     ClassSet classSetB = _classSets[b.declaration];
     if (classSetA == null || classSetB == null) return false;
     // TODO(johnniwinther): Implement an optimized query on [ClassSet].
@@ skipping 238 matching lines @@
       if (!rootNode.isInstantiated) {
         // No subclass needs noSuchMethod handling since they are all
         // uninstantiated.
         return false;
       }
       ClassElement rootClass = rootNode.cls;
       if (hasConcreteMatch(rootClass, selector)) {
         // The root subclass has a concrete implementation so no subclass needs
         // noSuchMethod handling.
         return false;
-      } else if (rootNode.isDirectlyInstantiated) {
+      } else if (rootNode.isRootInstantiated) {
         // The root class need noSuchMethod handling.
         return true;
       }
       IterationStep result = rootNode.forEachSubclass((ClassElement subclass) {
         if (hasConcreteMatch(subclass, selector, stopAtSuperclass: rootClass)) {
           // Found a match - skip all subclasses.
           return IterationStep.SKIP_SUBCLASSES;
         } else {
           // Stop fast - we found a need for noSuchMethod handling.
           return IterationStep.STOP;
         }
-      }, ClassHierarchyNode.DIRECTLY_INSTANTIATED, strict: true);
+      }, ClassHierarchyNode.ROOT_INSTANTIATED, strict: true);
       // We stopped fast so we need noSuchMethod handling.
       return result == IterationStep.STOP;
     }
 
     ClassSet classSet = getClassSet(base);
     ClassHierarchyNode node = classSet.node;
     if (query == ClassQuery.EXACT) {
       return node.isDirectlyInstantiated && !hasConcreteMatch(base, selector);
     } else if (query == ClassQuery.SUBCLASS) {
       return subclassesNeedNoSuchMethod(node);
@@ skipping 141 matching lines @@
         cls.implementsFunction(coreClasses)) {
       ClassSet subtypeSet = _ensureClassSet(coreClasses.functionClass);
       subtypeSet.addSubtype(node);
     }
     if (!node.isInstantiated && node.parentNode != null) {
       _updateSuperClassHierarchyNodeForClass(node.parentNode);
     }
   }
 
   void _updateClassHierarchyNodeForClass(ClassElement cls,
-      {bool directlyInstantiated: false}) {
+      {bool directlyInstantiated: false, bool abstractlyInstantiated: false}) {
     ClassHierarchyNode node = getClassHierarchyNode(cls);
     _updateSuperClassHierarchyNodeForClass(node);
     if (directlyInstantiated) {
       node.isDirectlyInstantiated = true;
     }
+    if (abstractlyInstantiated) {
+      node.isAbstractlyInstantiated = true;
+    }
   }
 
   ClosedWorld closeWorld() {
     /// Updates the `isDirectlyInstantiated` and `isIndirectlyInstantiated`
     /// properties of the [ClassHierarchyNode] for [cls].
 
-    void addSubtypes(ClassElement cls) {
+    void addSubtypes(ClassElement cls, EnumSet<Instantiation> instantiations) {
       if (_compiler.options.hasIncrementalSupport &&
           !alreadyPopulated.add(cls)) {
         return;
       }
       assert(cls.isDeclaration);
       if (!cls.isResolved) {
         reporter.internalError(cls, 'Class "${cls.name}" is not resolved.');
       }
 
-      _updateClassHierarchyNodeForClass(cls, directlyInstantiated: true);
+      _updateClassHierarchyNodeForClass(cls,
+          directlyInstantiated:
+              instantiations.contains(Instantiation.DIRECTLY_INSTANTIATED),
+          abstractlyInstantiated:
+              instantiations.contains(Instantiation.ABSTRACTLY_INSTANTIATED));
 
       // Walk through the superclasses, and record the types
       // implemented by that type on the superclasses.
       ClassElement superclass = cls.superclass;
       while (superclass != null) {
         Set<Element> typesImplementedBySubclassesOfCls =
             _typesImplementedBySubclasses.putIfAbsent(
                 superclass, () => new Set<ClassElement>());
         for (DartType current in cls.allSupertypes) {
           typesImplementedBySubclassesOfCls.add(current.element);
         }
         superclass = superclass.superclass;
       }
     }
 
     // Use the [:seenClasses:] set to include non-instantiated
     // classes: if the superclass of these classes require RTI, then
     // they also need RTI, so that a constructor passes the type
     // variables to the super constructor.
-    _compiler.resolverWorld.directlyInstantiatedClasses.forEach(addSubtypes);
+    _compiler.resolverWorld.forEachInstantiatedClass(addSubtypes);
 
     _closed = true;
     return this;
   }
 
   @override
   String dump([ClassElement cls]) {
     StringBuffer sb = new StringBuffer();
     if (cls != null) {
       sb.write("Classes in the closed world related to $cls:\n");
@@ skipping 161 matching lines @@
   /// Only the class itself is included.
   EXACT,
 
   /// The class and all subclasses (transitively) are included.
   SUBCLASS,
 
   /// The class and all classes that implement or subclass it (transitively)
   /// are included.
   SUBTYPE,
 }