Replace ClosedWorld.backend with ClosedWorld.backendClasses

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 Backend;
+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,
@@ skipping 13 matching lines @@
 
 /// 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 {
-  // TODO(johnniwinther): Refine this into a `BackendClasses` interface.
-  Backend get backend;
+  /// 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.
   bool isDirectlyInstantiated(ClassElement cls);
 
   /// Returns `true` if [cls] is indirectly instantiated, that is through a
   /// subclass.
@@ skipping 439 matching lines @@
     if (classSet == null) {
       // Vacuously true.
       return true;
     }
     return classSet.hasOnlyInstantiatedSubclasses;
   }
 
   @override
   ClassElement getLubOfInstantiatedSubclasses(ClassElement cls) {
     assert(isClosed);
-    if (backend.isJsInterop(cls)) {
-      return backend.helpers.jsJavaScriptObjectClass;
+    if (_backend.isJsInterop(cls)) {
+      return _backend.helpers.jsJavaScriptObjectClass;
     }
     ClassHierarchyNode hierarchy = _classHierarchyNodes[cls.declaration];
     return hierarchy != null
         ? hierarchy.getLubOfInstantiatedSubclasses()
         : null;
   }
 
   @override
   ClassElement getLubOfInstantiatedSubtypes(ClassElement cls) {
     assert(isClosed);
-    if (backend.isJsInterop(cls)) {
-      return backend.helpers.jsJavaScriptObjectClass;
+    if (_backend.isJsInterop(cls)) {
+      return _backend.helpers.jsJavaScriptObjectClass;
     }
     ClassSet classSet = _classSets[cls.declaration];
     return classSet != null ? classSet.getLubOfInstantiatedSubtypes() : null;
   }
 
   /// Returns an iterable over the common supertypes of the [classes].
   Iterable<ClassElement> commonSupertypesOf(Iterable<ClassElement> classes) {
     assert(isClosed);
     Iterator<ClassElement> iterator = classes.iterator;
     if (!iterator.moveNext()) return const <ClassElement>[];
@@ skipping 123 matching lines @@
   /// Returns `true` if any subclass of [superclass] implements [type].
   bool hasAnySubclassThatImplements(
       ClassElement superclass, ClassElement type) {
     assert(isClosed);
     Set<ClassElement> subclasses = typesImplementedBySubclassesOf(superclass);
     if (subclasses == null) return false;
     return subclasses.contains(type);
   }
 
   final Compiler _compiler;
-  JavaScriptBackend get backend => _compiler.backend;
+  BackendClasses get backendClasses => _backend.backendClasses;
+  JavaScriptBackend get _backend => _compiler.backend;
   CommonMasks get commonMasks => _compiler.commonMasks;
   final FunctionSet allFunctions;
   final Set<Element> functionsCalledInLoop = new Set<Element>();
   final Map<Element, SideEffects> sideEffects = new Map<Element, SideEffects>();
 
   final Set<TypedefElement> _allTypedefs = new Set<TypedefElement>();
 
   final Map<ClassElement, Set<MixinApplicationElement>> _mixinUses =
       new Map<ClassElement, Set<MixinApplicationElement>>();
   Map<ClassElement, List<MixinApplicationElement>> _liveMixinUses;
@@ skipping 14 matching lines @@
 
   final Set<Element> elementsThatCannotThrow = new Set<Element>();
 
   final Set<Element> functionsThatMightBePassedToApply =
       new Set<FunctionElement>();
 
   final Set<Element> alreadyPopulated;
 
   bool get isClosed => _closed;
 
-  // Used by selectors.

[Johnni Winther, 2016/09/26 14:05:56]

No it isn't!

-  bool isForeign(Element element) {
-    return backend.isForeign(element);
-  }
-
   Set<ClassElement> typesImplementedBySubclassesOf(ClassElement cls) {
     return _typesImplementedBySubclasses[cls.declaration];
   }
 
   WorldImpl(Compiler compiler)
       : allFunctions = new FunctionSet(compiler),
         this._compiler = compiler,
         alreadyPopulated = compiler.cacheStrategy.newSet();
 
   CoreClasses get coreClasses => _compiler.coreClasses;
@@ skipping 195 matching lines @@
   void addFunctionCalledInLoop(Element element) {
     functionsCalledInLoop.add(element.declaration);
   }
 
   bool isCalledInLoop(Element element) {
     return functionsCalledInLoop.contains(element.declaration);
   }
 
   bool fieldNeverChanges(Element element) {
     if (!element.isField) return false;
-    if (backend.isNative(element)) {
+    if (_backend.isNative(element)) {
       // Some native fields are views of data that may be changed by operations.
       // E.g. node.firstChild depends on parentNode.removeBefore(n1, n2).
       // TODO(sra): Refine the effect classification so that native effects are
       // distinct from ordinary Dart effects.
       return false;
     }
 
     if (element.isFinal || element.isConst) {
       return true;
     }
@@ skipping 80 matching lines @@
       return getMightBePassedToApply(element.expression);
     }
     return functionsThatMightBePassedToApply.contains(element);
   }
 
   @override
   bool getCurrentlyKnownMightBePassedToApply(Element element) {
     return getMightBePassedToApply(element);
   }
 }