Extract InterceptorData from JavaScriptBackend.

pkg/compiler/lib/src/js_backend/interceptor_data.dart

+// Copyright (c) 2017, 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 js_backend.interceptor_data;
+
+import '../common/names.dart' show Identifiers;
+import '../core_types.dart' show CommonElements;
+import '../elements/elements.dart';
+import '../js/js.dart' as jsAst;
+import '../types/types.dart' show TypeMask;
+import '../universe/selector.dart';
+import '../world.dart' show ClosedWorld;
+import 'backend_helpers.dart';
+import 'namer.dart';
+import 'native_data.dart';
+
+class InterceptorData {
+  final NativeData _nativeData;
+  final BackendHelpers _helpers;
+  final CommonElements _commonElements;
+  ClosedWorld _closedWorld;
+
+  /// A collection of selectors that must have a one shot interceptor generated.
+  final Map<jsAst.Name, Selector> oneShotInterceptors =
+      <jsAst.Name, Selector>{};
+
+  /// The members of instantiated interceptor classes: maps a member name to the
+  /// list of members that have that name. This map is used by the codegen to
+  /// know whether a send must be intercepted or not.
+  final Map<String, Set<Element>> interceptedElements =
+      <String, Set<Element>>{};
+
+  /// The members of mixin classes that are mixed into an instantiated
+  /// interceptor class.  This is a cached subset of [interceptedElements].
+  ///
+  /// Mixin methods are not specialized for the class they are mixed into.
+  /// Methods mixed into intercepted classes thus always make use of the
+  /// explicit receiver argument, even when mixed into non-interceptor classes.
+  ///
+  /// These members must be invoked with a correct explicit receiver even when
+  /// the receiver is not an intercepted class.
+  final Map<String, Set<Element>> interceptedMixinElements =
+      new Map<String, Set<Element>>();
+
+  /// A map of specialized versions of the [getInterceptorMethod].
+  ///
+  /// Since [getInterceptorMethod] is a hot method at runtime, we're always
+  /// specializing it based on the incoming type. The keys in the map are the
+  /// names of these specialized versions. Note that the generic version that
+  /// contains all possible type checks is also stored in this map.
+  final Map<jsAst.Name, Set<ClassElement>> specializedGetInterceptors =
+      <jsAst.Name, Set<ClassElement>>{};
+
+  /// Set of classes whose methods are intercepted.
+  final Set<ClassElement> _interceptedClasses = new Set<ClassElement>();
+
+  /// Set of classes used as mixins on intercepted (native and primitive)
+  /// classes. Methods on these classes might also be mixed in to regular Dart
+  /// (unintercepted) classes.
+  final Set<ClassElement> classesMixedIntoInterceptedClasses =
+      new Set<ClassElement>();
+
+  InterceptorData(this._nativeData, this._helpers, this._commonElements);
+
+  void onResolutionComplete(ClosedWorld closedWorld) {
+    _closedWorld = closedWorld;
+  }
+
+  bool isInterceptedMethod(MemberElement element) {
+    if (!element.isInstanceMember) return false;
+    if (element.isGenerativeConstructorBody) {
+      return _nativeData.isNativeOrExtendsNative(element.enclosingClass);
+    }
+    return interceptedElements[element.name] != null;
+  }
+
+  bool fieldHasInterceptedGetter(Element element) {
+    assert(element.isField);
+    return interceptedElements[element.name] != null;
+  }
+
+  bool fieldHasInterceptedSetter(Element element) {
+    assert(element.isField);
+    return interceptedElements[element.name] != null;
+  }
+
+  bool isInterceptedName(String name) {
+    return interceptedElements[name] != null;
+  }
+
+  bool isInterceptedSelector(Selector selector) {
+    return interceptedElements[selector.name] != null;
+  }
+
+  /// Returns `true` iff [selector] matches an element defined in a class mixed
+  /// into an intercepted class.  These selectors are not eligible for the
+  /// 'dummy explicit receiver' optimization.
+  bool isInterceptedMixinSelector(Selector selector, TypeMask mask) {
+    Set<Element> elements =
+        interceptedMixinElements.putIfAbsent(selector.name, () {
+      Set<Element> elements = interceptedElements[selector.name];
+      if (elements == null) return null;
+      return elements
+          .where((element) => classesMixedIntoInterceptedClasses
+              .contains(element.enclosingClass))
+          .toSet();
+    });
+
+    if (elements == null) return false;
+    if (elements.isEmpty) return false;
+    return elements.any((element) {
+      return selector.applies(element) &&
+          (mask == null ||
+              mask.canHit(element as MemberElement, selector, _closedWorld));
+    });
+  }
+
+  /// True if the given class is an internal class used for type inference
+  /// and never exists at runtime.
+  bool isCompileTimeOnlyClass(ClassElement class_) {
+    return class_ == _helpers.jsPositiveIntClass ||
+        class_ == _helpers.jsUInt32Class ||
+        class_ == _helpers.jsUInt31Class ||
+        class_ == _helpers.jsFixedArrayClass ||
+        class_ == _helpers.jsUnmodifiableArrayClass ||
+        class_ == _helpers.jsMutableArrayClass ||
+        class_ == _helpers.jsExtendableArrayClass;
+  }
+
+  final Map<String, Set<ClassElement>> interceptedClassesCache =
+      new Map<String, Set<ClassElement>>();
+  final Set<ClassElement> _noClasses = new Set<ClassElement>();
+
+  /// Returns a set of interceptor classes that contain a member named [name]
+  ///
+  /// Returns an empty set if there is no class. Do not modify the returned set.
+  Set<ClassElement> getInterceptedClassesOn(String name) {
+    Set<Element> intercepted = interceptedElements[name];
+    if (intercepted == null) return _noClasses;
+    return interceptedClassesCache.putIfAbsent(name, () {
+      // Populate the cache by running through all the elements and
+      // determine if the given selector applies to them.
+      Set<ClassElement> result = new Set<ClassElement>();
+      for (Element element in intercepted) {
+        ClassElement classElement = element.enclosingClass;
+        if (isCompileTimeOnlyClass(classElement)) continue;
+        if (_nativeData.isNativeOrExtendsNative(classElement) ||
+            interceptedClasses.contains(classElement)) {
+          result.add(classElement);
+        }
+        if (classesMixedIntoInterceptedClasses.contains(classElement)) {
+          Set<ClassElement> nativeSubclasses =
+              nativeSubclassesOfMixin(classElement);
+          if (nativeSubclasses != null) result.addAll(nativeSubclasses);
+        }
+      }
+      return result;
+    });
+  }
+
+  Set<ClassElement> nativeSubclassesOfMixin(ClassElement mixin) {
+    Iterable<MixinApplicationElement> uses = _closedWorld.mixinUsesOf(mixin);
+    Set<ClassElement> result = null;
+    for (MixinApplicationElement use in uses) {
+      _closedWorld.forEachStrictSubclassOf(use, (ClassElement subclass) {
+        if (_nativeData.isNativeOrExtendsNative(subclass)) {
+          if (result == null) result = new Set<ClassElement>();
+          result.add(subclass);
+        }
+      });
+    }
+    return result;
+  }
+
+  bool isInterceptorClass(ClassElement element) {
+    if (element == null) return false;
+    if (_nativeData.isNativeOrExtendsNative(element)) return true;
+    if (interceptedClasses.contains(element)) return true;
+    if (classesMixedIntoInterceptedClasses.contains(element)) return true;
+    return false;
+  }
+
+  jsAst.Name registerOneShotInterceptor(Selector selector, Namer namer) {
+    Set<ClassElement> classes = getInterceptedClassesOn(selector.name);
+    jsAst.Name name = namer.nameForGetOneShotInterceptor(selector, classes);
+    if (!oneShotInterceptors.containsKey(name)) {
+      registerSpecializedGetInterceptor(classes, namer);
+      oneShotInterceptors[name] = selector;
+    }
+    return name;
+  }
+
+  void addInterceptorsForNativeClassMembers(ClassElement cls) {
+    cls.forEachMember((ClassElement classElement, Element member) {
+      if (member.name == Identifiers.call) {
+        return;
+      }
+      if (member.isSynthesized) return;
+      // All methods on [Object] are shadowed by [Interceptor].
+      if (classElement == _commonElements.objectClass) return;
+      Set<Element> set = interceptedElements.putIfAbsent(
+          member.name, () => new Set<Element>());
+      set.add(member);
+    }, includeSuperAndInjectedMembers: true);
+
+    // Walk superclass chain to find mixins.
+    for (; cls != null; cls = cls.superclass) {
+      if (cls.isMixinApplication) {
+        MixinApplicationElement mixinApplication = cls;
+        classesMixedIntoInterceptedClasses.add(mixinApplication.mixin);
+      }
+    }
+  }
+
+  void addInterceptors(ClassElement cls) {
+    if (_interceptedClasses.add(cls)) {
+      cls.forEachMember((ClassElement classElement, Element member) {
+        // All methods on [Object] are shadowed by [Interceptor].
+        if (classElement == _commonElements.objectClass) return;
+        Set<Element> set = interceptedElements.putIfAbsent(
+            member.name, () => new Set<Element>());
+        set.add(member);
+      }, includeSuperAndInjectedMembers: true);
+    }
+    _interceptedClasses.add(_helpers.jsInterceptorClass);
+  }
+
+  Set<ClassElement> get interceptedClasses {
+    assert(_closedWorld != null);
+    return _interceptedClasses;
+  }
+
+  void registerSpecializedGetInterceptor(
+      Set<ClassElement> classes, Namer namer) {
+    jsAst.Name name = namer.nameForGetInterceptor(classes);
+    if (classes.contains(_helpers.jsInterceptorClass)) {
+      // We can't use a specialized [getInterceptorMethod], so we make
+      // sure we emit the one with all checks.
+      specializedGetInterceptors[name] = interceptedClasses;
+    } else {
+      specializedGetInterceptors[name] = classes;
+    }
+  }
+}