Less inequivalence on Hello World!

pkg/compiler/lib/src/js_emitter/runtime_type_generator.dart

 // Copyright (c) 2014, 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.js_emitter.runtime_type_generator;
 
 import '../closure.dart'
     show ClosureRepresentationInfo, ClosureFieldElement, ClosureConversionTask;
 import '../common.dart';
 import '../common/names.dart' show Identifiers;
-import '../common_elements.dart' show CommonElements;
-import '../elements/resolution_types.dart'
-    show ResolutionDartType, ResolutionFunctionType, ResolutionInterfaceType;
+import '../common_elements.dart' show CommonElements, ElementEnvironment;
 import '../elements/elements.dart'
-    show ClassElement, Element, FunctionElement, MixinApplicationElement;
+    show ClassElement, MethodElement, MixinApplicationElement;
 import '../elements/entities.dart';
 import '../elements/types.dart';
 import '../js/js.dart' as jsAst;
 import '../js/js.dart' show js;
 import '../js_backend/js_interop_analysis.dart';
 import '../js_backend/native_data.dart';
 import '../js_backend/namer.dart' show Namer;
 import '../js_backend/runtime_types.dart'
     show
         RuntimeTypesChecks,
         RuntimeTypesNeed,
         RuntimeTypesEncoder,
         RuntimeTypesSubstitutions,
         Substitution,
         TypeCheck,
         TypeChecks;
 import '../util/util.dart' show Setlet;
+import '../world.dart';
 
 import 'code_emitter_task.dart' show CodeEmitterTask;
 import 'type_test_registry.dart' show TypeTestRegistry;
 
 // Function signatures used in the generation of runtime type information.
 typedef void FunctionTypeSignatureEmitter(
-    Element method, ResolutionFunctionType methodType);
+    FunctionEntity method, FunctionType methodType);
 
-typedef void SubstitutionEmitter(Element element, {bool emitNull});
+typedef void SubstitutionEmitter(ClassEntity element, {bool emitNull});
 
 class TypeTestProperties {
   /// The index of the function type into the metadata.
   ///
   /// If the class doesn't have a function type this field is `null`.
   ///
   /// If the is tests were generated with `storeFunctionTypeInMetadata` set to
   /// `false`, this field is `null`, and the [properties] contain a property
   /// that encodes the function type.
   jsAst.Expression functionTypeIndex;
 
   /// The properties that must be installed on the prototype of the
-  /// JS constructor of the [ClassElement] for which the is checks were
+  /// JS constructor of the [ClassEntity] for which the is checks were
   /// generated.
   final Map<jsAst.Name, jsAst.Node> properties = <jsAst.Name, jsAst.Node>{};
 }
 
 class RuntimeTypeGenerator {
+  final ElementEnvironment _elementEnvironment;
   final CommonElements _commonElements;
+  final DartTypes _types;
+  final ClosedWorld _closedWorld;
   final ClosureConversionTask _closureDataLookup;
   final CodeEmitterTask emitterTask;
   final Namer _namer;
   final NativeData _nativeData;
   final RuntimeTypesChecks _rtiChecks;
   final RuntimeTypesEncoder _rtiEncoder;
   final RuntimeTypesNeed _rtiNeed;
   final RuntimeTypesSubstitutions _rtiSubstitutions;
   final JsInteropAnalysis _jsInteropAnalysis;
 
   RuntimeTypeGenerator(
+      this._elementEnvironment,
       this._commonElements,
+      this._types,
+      this._closedWorld,
       this._closureDataLookup,
       this.emitterTask,
       this._namer,
       this._nativeData,
       this._rtiChecks,
       this._rtiEncoder,
       this._rtiNeed,
       this._rtiSubstitutions,
       this._jsInteropAnalysis);
 
@@ skipping 10 matching lines @@
   /// Generates all properties necessary for is-checks on the [classElement].
   ///
   /// Returns an instance of [TypeTestProperties] that contains the properties
   /// that must be installed on the prototype of the JS constructor of the
   /// [classElement].
   ///
   /// If [storeFunctionTypeInMetadata] is `true`, stores the reified function
   /// type (if class has one) in the metadata object and stores its index in
   /// the result. This is only possible for function types that do not contain
   /// type variables.
-  TypeTestProperties generateIsTests(ClassEntity cls,
+  TypeTestProperties generateIsTests(ClassEntity classElement,
       {bool storeFunctionTypeInMetadata: true}) {
     TypeTestProperties result = new TypeTestProperties();
-    if (cls is! ClassElement) return result;
 
-    // TODO(johnniwinther): Handle class entities.
-    ClassElement classElement = cls;
-    assert(classElement.isDeclaration, failedAt(classElement));
+    assert(!(classElement is ClassElement && !classElement.isDeclaration),
+        failedAt(classElement));
 
     /// Generates an is-test if the test is not inherited from a superclass
     /// This assumes that for every class an is-tests is generated
     /// dynamically at runtime. We also always generate tests against
     /// native classes.
     /// TODO(herhut): Generate tests for native classes dynamically, as well.
-    void generateIsTest(ClassElement other) {
+    void generateIsTest(ClassEntity other) {
       if (_nativeData.isNativeClass(classElement) ||
-          !classElement.isSubclassOf(other)) {
+          !_closedWorld.isSubclassOf(classElement, other)) {
         result.properties[_namer.operatorIs(other)] = js('1');
       }
     }
 
     void generateFunctionTypeSignature(
-        FunctionElement method, ResolutionFunctionType type) {
-      assert(method.isImplementation);
+        FunctionEntity method, FunctionType type) {
+      assert(!(method is MethodElement && !method.isImplementation));
       jsAst.Expression thisAccess = new jsAst.This();
       if (!method.isAbstract) {
         ClosureRepresentationInfo closureData =
             _closureDataLookup.getClosureRepresentationInfo(method);
         if (closureData != null) {
           ClosureFieldElement thisLocal = closureData.thisFieldEntity;
           if (thisLocal != null) {
             jsAst.Name thisName = _namer.instanceFieldPropertyName(thisLocal);
             thisAccess = js('this.#', thisName);
           }
         }
       }
 
       if (storeFunctionTypeInMetadata && !type.containsTypeVariables) {
         result.functionTypeIndex =
             emitterTask.metadataCollector.reifyType(type);
       } else {
         jsAst.Expression encoding = _rtiEncoder.getSignatureEncoding(
             emitterTask.emitter, type, thisAccess);
         jsAst.Name operatorSignature = _namer.asName(_namer.operatorSignature);
         result.properties[operatorSignature] = encoding;
       }
     }
 
-    void generateSubstitution(ClassElement cls, {bool emitNull: false}) {
-      if (cls.typeVariables.isEmpty) return;
+    void generateSubstitution(ClassEntity cls, {bool emitNull: false}) {
+      if (!_elementEnvironment.isGenericClass(cls)) return;
       jsAst.Expression expression;
       bool needsNativeCheck =
           emitterTask.nativeEmitter.requiresNativeIsCheck(cls);
       Substitution substitution =
           _rtiSubstitutions.getSubstitution(classElement, cls);
       if (substitution != null) {
         expression =
             _rtiEncoder.getSubstitutionCode(emitterTask.emitter, substitution);
       }
       if (expression == null && (emitNull || needsNativeCheck)) {
         expression = new jsAst.LiteralNull();
       }
       if (expression != null) {
         result.properties[_namer.substitutionName(cls)] = expression;
       }
     }
 
     void generateTypeCheck(TypeCheck check) {
-      ClassElement checkedClass = check.cls;
+      ClassEntity checkedClass = check.cls;
       generateIsTest(checkedClass);
       Substitution substitution = check.substitution;
       if (substitution != null) {
         jsAst.Expression body =
             _rtiEncoder.getSubstitutionCode(emitterTask.emitter, substitution);
         result.properties[_namer.substitutionName(checkedClass)] = body;
       }
     }
 
-    _generateIsTestsOn(classElement, (Element e) {
-      generateIsTest(e);
-    }, (Element e, ResolutionFunctionType t) {
-      generateFunctionTypeSignature(e, t);
-    },
-        (Element e, {bool emitNull: false}) =>
+    _generateIsTestsOn(
+        classElement,
+        generateIsTest,
+        generateFunctionTypeSignature,
+        (ClassEntity e, {bool emitNull: false}) =>
             generateSubstitution(e, emitNull: emitNull),
         generateTypeCheck);
 
     if (classElement == _commonElements.jsJavaScriptFunctionClass) {
       var type = _jsInteropAnalysis.buildJsFunctionType();
       if (type != null) {
         jsAst.Expression thisAccess = new jsAst.This();
         jsAst.Expression encoding = _rtiEncoder.getSignatureEncoding(
             emitterTask.emitter, type, thisAccess);
         jsAst.Name operatorSignature = _namer.asName(_namer.operatorSignature);
         result.properties[operatorSignature] = encoding;
       }
     }
     return result;
   }
 
   /**
    * Generate "is tests" for [cls] itself, and the "is tests" for the
    * classes it implements and type argument substitution functions for these
    * tests.   We don't need to add the "is tests" of the super class because
    * they will be inherited at runtime, but we may need to generate the
    * substitutions, because they may have changed.
    */
   void _generateIsTestsOn(
-      ClassElement cls,
-      void generateIsTest(Element element),
+      ClassEntity cls,
+      void generateIsTest(ClassEntity element),
       FunctionTypeSignatureEmitter generateFunctionTypeSignature,
       SubstitutionEmitter generateSubstitution,
       void emitTypeCheck(TypeCheck check)) {
-    Setlet<ClassElement> generated = new Setlet<ClassElement>();
+    Setlet<ClassEntity> generated = new Setlet<ClassEntity>();
 
     if (checkedClasses.contains(cls)) {
       generateIsTest(cls);
       generateSubstitution(cls);
       generated.add(cls);
     }
 
     // Precomputed is checks.
     TypeChecks typeChecks = _rtiChecks.requiredChecks;
     Iterable<TypeCheck> classChecks = typeChecks[cls];
     if (classChecks != null) {
       for (TypeCheck check in classChecks) {
         if (!generated.contains(check.cls)) {
           emitTypeCheck(check);
           generated.add(check.cls);
         }
       }
     }
 
-    ClassElement superclass = cls.superclass;
+    ClassEntity superclass = _elementEnvironment.getSuperClass(cls);
 
-    bool haveSameTypeVariables(ClassElement a, ClassElement b) {
+    bool haveSameTypeVariables(ClassEntity a, ClassEntity b) {
       if (a.isClosure) return true;
       return _rtiSubstitutions.isTrivialSubstitution(a, b);
     }
 
     bool supertypesNeedSubstitutions = false;
 
     if (superclass != null &&
         superclass != _commonElements.objectClass &&
         !haveSameTypeVariables(cls, superclass)) {
       // We cannot inherit the generated substitutions, because the type
       // variable layout for this class is different.  Instead we generate
       // substitutions for all checks and make emitSubstitution a NOP for the
       // rest of this function.
 
       // TODO(karlklose): move the computation of these checks to
       // RuntimeTypeInformation.
       while (superclass != null) {
         if (_rtiNeed.classNeedsRti(superclass)) {
           generateSubstitution(superclass, emitNull: true);
           generated.add(superclass);
         }
-        superclass = superclass.superclass;
+        superclass = _elementEnvironment.getSuperClass(superclass);
       }
       supertypesNeedSubstitutions = true;
     }
 
     if (cls is MixinApplicationElement) {
       supertypesNeedSubstitutions = true;
     }
 
     if (supertypesNeedSubstitutions) {
-      for (ResolutionInterfaceType supertype in cls.allSupertypes) {
-        ClassElement superclass = supertype.element;
-        if (generated.contains(superclass)) continue;
+      _elementEnvironment.forEachSupertype(cls, (InterfaceType supertype) {
+        ClassEntity superclass = supertype.element;
+        if (generated.contains(superclass)) return;
 
         if (classesUsingTypeVariableTests.contains(superclass) ||
             _rtiNeed.classUsesTypeVariableExpression(superclass) ||
             checkedClasses.contains(superclass)) {
           // Generate substitution.  If no substitution is necessary, emit
           // `null` to overwrite a (possibly) existing substitution from the
           // super classes.
           generateSubstitution(superclass, emitNull: true);
         }
-      }
+      });
 
       void emitNothing(_, {emitNull}) {}
 
       generateSubstitution = emitNothing;
     }
 
     // A class that defines a `call` method implicitly implements
     // [Function] and needs checks for all typedefs that are used in is-checks.
     if (checkedClasses.contains(_commonElements.functionClass) ||
         checkedFunctionTypes.isNotEmpty) {
-      Element call = cls.lookupLocalMember(Identifiers.call);
-      if (call == null) {
-        // If [cls] is a closure, it has a synthetic call operator method.
-        call = cls.lookupConstructorBody(Identifiers.call);

[Siggi Cherem (dart-lang), 2017/06/23 19:49:28]

Was this basically dead code?

I'm guessing this used to be cls.lookupBackendMember, but we don't declare
`.call` in closures using addBackendMember because we create the entire class
explicitly, correct? 

[Johnni Winther, 2017/06/26 09:17:44]

Yes. Yes.

-      }
+      MemberEntity call =
+          _elementEnvironment.lookupClassMember(cls, Identifiers.call);
       if (call != null && call.isFunction) {
-        FunctionElement callFunction = call;
+        FunctionEntity callFunction = call;
         // A superclass might already implement the Function interface. In such
-        // a case, we can avoid emiting the is test here.
-        if (!cls.superclass.implementsFunction(_commonElements)) {
+        // a case, we can avoid emitting the is test here.
+        ClassEntity superclass = _elementEnvironment.getSuperClass(cls);
+        if (!_closedWorld.isSubclassOf(
+            superclass, _commonElements.functionClass)) {
           _generateInterfacesIsTests(_commonElements.functionClass,
               generateIsTest, generateSubstitution, generated);
         }
-        ResolutionFunctionType callType = callFunction.type;
+        FunctionType callType =
+            _elementEnvironment.getFunctionType(callFunction);
         generateFunctionTypeSignature(callFunction, callType);
       }
     }
 
-    for (ResolutionDartType interfaceType in cls.interfaces) {
+    for (InterfaceType interfaceType in _types.getInterfaces(cls)) {
       _generateInterfacesIsTests(interfaceType.element, generateIsTest,
           generateSubstitution, generated);
     }
   }
 
   /**
    * Generate "is tests" where [cls] is being implemented.
    */
   void _generateInterfacesIsTests(
-      ClassElement cls,
-      void generateIsTest(ClassElement element),
+      ClassEntity cls,
+      void generateIsTest(ClassEntity element),
       SubstitutionEmitter generateSubstitution,
-      Set<Element> alreadyGenerated) {
-    void tryEmitTest(ClassElement check) {
+      Set<ClassEntity> alreadyGenerated) {
+    void tryEmitTest(ClassEntity check) {
       if (!alreadyGenerated.contains(check) && checkedClasses.contains(check)) {
         alreadyGenerated.add(check);
         generateIsTest(check);
         generateSubstitution(check);
       }
     }
 
     tryEmitTest(cls);
 
-    for (ResolutionDartType interfaceType in cls.interfaces) {
-      Element element = interfaceType.element;
+    for (InterfaceType interfaceType in _types.getInterfaces(cls)) {
+      ClassEntity element = interfaceType.element;
       tryEmitTest(element);
       _generateInterfacesIsTests(
           element, generateIsTest, generateSubstitution, alreadyGenerated);
     }
 
     // We need to also emit "is checks" for the superclass and its supertypes.
-    ClassElement superclass = cls.superclass;
+    ClassEntity superclass = _elementEnvironment.getSuperClass(cls);
     if (superclass != null) {
       tryEmitTest(superclass);
       _generateInterfacesIsTests(
           superclass, generateIsTest, generateSubstitution, alreadyGenerated);
     }
   }
 }