| // Copyright (c) 2018, 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 vm.transformations.mixin_deduplication; |
| |
| import 'package:kernel/ast.dart'; |
| |
| /// De-duplication of identical mixin applications. |
| void transformComponent(Component component) { |
| final deduplicateMixins = new DeduplicateMixinsTransformer(); |
| component.libraries.forEach(deduplicateMixins.visitLibrary); |
| } |
| |
| class _DeduplicateMixinKey { |
| final Class _class; |
| _DeduplicateMixinKey(this._class); |
| |
| @override |
| bool operator ==(Object other) { |
| if (other is _DeduplicateMixinKey) { |
| final thisClass = _class; |
| final otherClass = other._class; |
| if (identical(thisClass, otherClass)) { |
| return true; |
| } |
| // Do not deduplicate parameterized mixin applications. |
| if (thisClass.typeParameters.isNotEmpty || |
| otherClass.typeParameters.isNotEmpty) { |
| return false; |
| } |
| // Deduplicate mixin applications with matching supertype, mixed-in type |
| // and implemented interfaces. |
| return thisClass.supertype == otherClass.supertype && |
| thisClass.mixedInType == otherClass.mixedInType && |
| listEquals(thisClass.implementedTypes, otherClass.implementedTypes); |
| } |
| return false; |
| } |
| |
| @override |
| int get hashCode { |
| if (_class.typeParameters.isNotEmpty) { |
| return _class.hashCode; |
| } |
| int hash = 31; |
| hash = 0x3fffffff & (hash * 31 + _class.supertype.hashCode); |
| hash = 0x3fffffff & (hash * 31 + _class.mixedInType.hashCode); |
| for (var i in _class.implementedTypes) { |
| hash = 0x3fffffff & (hash * 31 + i.hashCode); |
| } |
| return hash; |
| } |
| } |
| |
| class DeduplicateMixinsTransformer extends Transformer { |
| final _canonicalMixins = new Map<_DeduplicateMixinKey, Class>(); |
| final _duplicatedMixins = new Map<Class, Class>(); |
| |
| @override |
| TreeNode visitLibrary(Library node) { |
| if (!node.isExternal) { |
| transformList(node.classes, this, node); |
| } |
| return node; |
| } |
| |
| @override |
| TreeNode visitClass(Class c) { |
| if (c.enclosingLibrary.isExternal) { |
| return c; |
| } |
| |
| if (_duplicatedMixins.containsKey(c)) { |
| return null; // Class was de-duplicated already, just remove it. |
| } |
| |
| if (c.supertype != null) { |
| c.supertype = _transformSupertype(c.supertype, c, true); |
| } |
| if (c.mixedInType != null) { |
| throw 'All mixins should be transformed already.'; |
| } |
| transformSupertypeList(c.implementedTypes, this); |
| |
| if (!c.isAnonymousMixin) { |
| return c; |
| } |
| |
| Class canonical = |
| _canonicalMixins.putIfAbsent(new _DeduplicateMixinKey(c), () => c); |
| assert(canonical != null); |
| |
| if (canonical != c) { |
| c.canonicalName?.unbind(); |
| _duplicatedMixins[c] = canonical; |
| // print('Replacing $c with $canonical'); |
| return null; // Remove class. |
| } |
| |
| return c; |
| } |
| |
| @override |
| Supertype visitSupertype(Supertype node) { |
| return _transformSupertype(node, null, false); |
| } |
| |
| Supertype _transformSupertype( |
| Supertype supertype, Class cls, bool isSuperclass) { |
| Class oldSuper = supertype.classNode; |
| Class newSuper = visitClass(oldSuper); |
| if (newSuper == null) { |
| Class canonicalSuper = _duplicatedMixins[oldSuper]; |
| assert(canonicalSuper != null); |
| supertype = new Supertype(canonicalSuper, supertype.typeArguments); |
| if (isSuperclass) { |
| _correctForwardingConstructors(cls, oldSuper, canonicalSuper); |
| } |
| } |
| return supertype; |
| } |
| |
| @override |
| TreeNode defaultTreeNode(TreeNode node) => |
| throw 'Unexpected node ${node.runtimeType}: $node'; |
| } |
| |
| /// Corrects forwarding constructors inserted by mixin resolution after |
| /// replacing superclass. |
| void _correctForwardingConstructors(Class c, Class oldSuper, Class newSuper) { |
| for (var constructor in c.constructors) { |
| for (var initializer in constructor.initializers) { |
| if ((initializer is SuperInitializer) && |
| initializer.target.enclosingClass == oldSuper) { |
| Constructor replacement = null; |
| for (var c in newSuper.constructors) { |
| if (c.name == initializer.target.name) { |
| replacement = c; |
| break; |
| } |
| } |
| if (replacement == null) { |
| throw 'Unable to find a replacement for $c in $newSuper'; |
| } |
| initializer.target = replacement; |
| } |
| } |
| } |
| } |