Copy Rasta visitor to dart2js.

pkg/compiler/lib/src/kernel/kernel.dart

+// Copyright (c) 2016, 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.md file.
+
+import 'dart:collection' show Queue;
+
+import 'package:kernel/ast.dart' as ir;
+import 'package:kernel/checks.dart' show CheckParentPointers;
+import 'package:kernel/frontend/super_calls.dart' show moveSuperCallLast;
+
+import '../compiler.dart' show Compiler;
+import '../constants/expressions.dart' show TypeConstantExpression;
+import '../dart_types.dart'
+    show DartType, FunctionType, InterfaceType, TypeKind, TypeVariableType;
+import '../diagnostics/messages.dart' show MessageKind;
+import '../diagnostics/spannable.dart' show Spannable;
+import '../elements/elements.dart'
+    show
+        ClassElement,
+        ConstructorElement,
+        Element,
+        FieldElement,
+        FunctionElement,
+        LibraryElement,
+        MixinApplicationElement,
+        TypeVariableElement;
+import '../elements/modelx.dart' show ErroneousFieldElementX;
+import '../tree/tree.dart' show FunctionExpression, Node;
+import 'kernel_visitor.dart' show IrFunction, KernelVisitor;
+
+typedef void WorkAction();
+
+class WorkItem {
+  final Element element;
+  final WorkAction action;
+
+  WorkItem(this.element, this.action);
+}
+
+class Kernel {
+  final Compiler compiler;
+
+  final Map<LibraryElement, ir.Library> libraries =
+      <LibraryElement, ir.Library>{};
+
+  final Map<ClassElement, ir.Class> classes = <ClassElement, ir.Class>{};
+
+  final Map<FunctionElement, ir.Member> functions =
+      <FunctionElement, ir.Member>{};
+
+  final Map<FieldElement, ir.Field> fields = <FieldElement, ir.Field>{};
+
+  final Map<TypeVariableElement, ir.TypeParameter> typeParameters =
+      <TypeVariableElement, ir.TypeParameter>{};
+
+  final Map<TypeVariableElement, ir.TypeParameter> factoryTypeParameters =
+      <TypeVariableElement, ir.TypeParameter>{};
+
+  final Set<ir.TreeNode> checkedNodes = new Set<ir.TreeNode>();
+
+  final Map<LibraryElement, Map<String, int>> mixinApplicationNamesByLibrary =
+      <LibraryElement, Map<String, int>>{};
+
+  /// FIFO queue of work that needs to be completed before the returned AST
+  /// nodes are correct.
+  final Queue<WorkItem> workQueue = new Queue<WorkItem>();
+
+  Kernel(this.compiler);
+
+  void addWork(Element element, WorkAction action) {
+    workQueue.addLast(new WorkItem(element, action));
+  }
+
+  void checkMember(Element key, ir.TreeNode value) {
+    if (!checkedNodes.add(value)) return;
+    if (value.parent == null) {
+      internalError(key, "Missing parent on IR node.");
+    }
+    try {
+      CheckParentPointers.check(value);
+    } catch (e, s) {
+      internalError(key, "$e\n$s");
+    }
+  }
+
+  void checkLibrary(Element key, ir.Library library) {
+    if (!checkedNodes.add(library)) return;
+    CheckParentPointers.check(library);
+  }
+
+  void processWorkQueue() {
+    while (workQueue.isNotEmpty) {
+      WorkItem work = workQueue.removeFirst();
+      work.action();
+    }
+    assert(() {
+      libraries.forEach(checkLibrary);
+      classes.forEach(checkMember);
+      functions.forEach(checkMember);
+      fields.forEach(checkMember);
+      return true;
+    });
+  }
+
+  ir.Name irName(String name, Element element) {
+    ir.Library irLibrary = null;
+    if (name.startsWith("_")) {
+      ClassElement cls = element.enclosingClass;
+      if (cls != null && cls.isMixinApplication) {
+        MixinApplicationElement mixinApplication = cls;
+        element = mixinApplication.mixin;
+      }
+      irLibrary = libraryToIr(element.library);
+    }
+    return new ir.Name(name, irLibrary);
+  }
+
+  ir.Library libraryToIr(LibraryElement library) {
+    library = library.declaration;
+    return libraries.putIfAbsent(library, () {
+      String name = library.hasLibraryName ? library.libraryName : null;
+      ir.Library libraryNode = new ir.Library(library.canonicalUri,
+          name: name, classes: null, procedures: null, fields: null);
+      addWork(library, () {
+        Queue<ir.Class> classes = new Queue<ir.Class>();
+        Queue<ir.Member> members = new Queue<ir.Member>();
+        library.implementation.forEachLocalMember((Element e) {
+          if (e.isClass) {
+            classes.addFirst(classToIr(e));
+          } else if (e.isFunction || e.isAccessor) {
+            members.addFirst(functionToIr(e));
+          } else if (e.isField) {
+            members.addFirst(fieldToIr(e));
+          } else if (e.isTypedef) {
+            // Ignored, typedefs are unaliased on use.
+          } else {
+            internalError(e, "Unhandled library member: $e");
+          }
+        });
+        // The elements were inserted in reverse order as forEachLocalMember
+        // above gives them in reversed order.
+        classes.forEach(libraryNode.addClass);
+        members.forEach(libraryNode.addMember);
+      });
+      return libraryNode;
+    });
+  }
+
+  /// Compute a name for [cls]. We want to have unique names in a library, but
+  /// mixin applications can lead to multiple classes with the same name. So
+  /// for those we append `#` and a number.
+  String computeName(ClassElement cls) {
+    String name = cls.name;
+    if (!cls.isUnnamedMixinApplication) return name;
+    Map<String, int> mixinApplicationNames = mixinApplicationNamesByLibrary
+        .putIfAbsent(cls.library.implementation, () => <String, int>{});
+    int count = mixinApplicationNames.putIfAbsent(name, () => 0);
+    mixinApplicationNames[name] = count + 1;
+    return "$name#$count";
+  }
+
+  ir.Class classToIr(ClassElement cls) {
+    cls = cls.declaration;
+    return classes.putIfAbsent(cls, () {
+      String name = computeName(cls);
+      ir.Class classNode = new ir.Class(
+          name: name,
+          isAbstract: cls.isAbstract,
+          typeParameters: null,
+          implementedTypes: null,
+          constructors: null,
+          procedures: null,
+          fields: null);
+      addWork(cls, () {
+        if (cls.supertype != null) {
+          classNode.supertype = interfaceTypeToIr(cls.supertype);
+        }
+        classNode.parent = libraryToIr(cls.library);
+        if (cls.isUnnamedMixinApplication) {
+          classNode.enclosingLibrary.addClass(classNode);
+        }
+        cls.implementation
+            .forEachMember((ClassElement enclosingClass, Element member) {
+          if (member.enclosingClass.declaration != cls) {
+            internalError(cls, "`$member` isn't mine.");
+          } else if (member.isFunction ||
+              member.isAccessor ||
+              member.isConstructor) {
+            classNode.addMember(functionToIr(member));
+          } else if (member.isField) {
+            classNode.addMember(fieldToIr(member));
+          } else {
+            internalError(member, "Unhandled class member: $member");
+          }
+        });
+        classNode.typeParameters.addAll(typeVariablesToIr(cls.typeVariables));
+        for (ir.InterfaceType interface in typesToIr(cls.interfaces.toList())) {
+          classNode.implementedTypes.add(interface);
+        }
+      });
+      return classNode;
+    });
+  }
+
+  bool hasHierarchyProblem(ClassElement cls) => cls.hasIncompleteHierarchy;
+
+  ir.InterfaceType interfaceTypeToIr(InterfaceType type) {
+    ir.Class cls = classToIr(type.element);
+    if (type.typeArguments.isEmpty) {
+      return cls.rawType;
+    } else {
+      return new ir.InterfaceType(cls, typesToIr(type.typeArguments));
+    }
+  }
+
+  // TODO(ahe): Remove this method when dart2js support generic type arguments.
+  List<ir.TypeParameter> typeParametersNotImplemented() {
+    return const <ir.TypeParameter>[];
+  }
+
+  ir.FunctionType functionTypeToIr(FunctionType type) {
+    List<ir.TypeParameter> typeParameters = typeParametersNotImplemented();
+    int requiredParameterCount = type.parameterTypes.length;
+    List<ir.DartType> positionalParameters =
+        new List<ir.DartType>.from(typesToIr(type.parameterTypes))
+          ..addAll(typesToIr(type.optionalParameterTypes));
+    Map<String, ir.DartType> namedParameters = <String, ir.DartType>{};
+    for (int i = 0; i < type.namedParameters.length; i++) {
+      namedParameters[type.namedParameters[i]] =
+          typeToIr(type.namedParameterTypes[i]);
+    }
+    ir.DartType returnType = typeToIr(type.returnType);
+
+    return new ir.FunctionType(positionalParameters, returnType,
+        namedParameters: namedParameters,
+        typeParameters: typeParameters,
+        requiredParameterCount: requiredParameterCount);
+  }
+
+  ir.TypeParameterType typeVariableTypeToIr(TypeVariableType type) {
+    return new ir.TypeParameterType(typeVariableToIr(type.element));
+  }
+
+  List<ir.DartType> typesToIr(List<DartType> types) {
+    List<ir.DartType> result = new List<ir.DartType>(types.length);
+    for (int i = 0; i < types.length; i++) {
+      result[i] = typeToIr(types[i]);
+    }
+    return result;
+  }
+
+  ir.DartType typeToIr(DartType type) {
+    switch (type.kind) {
+      case TypeKind.FUNCTION:
+        return functionTypeToIr(type);
+
+      case TypeKind.INTERFACE:
+        return interfaceTypeToIr(type);
+
+      case TypeKind.STATEMENT:
+        throw "Internal error: statement type: $type.";
+
+      case TypeKind.TYPEDEF:
+        type.computeUnaliased(compiler.resolution);
+        return typeToIr(type.unaliased);
+
+      case TypeKind.TYPE_VARIABLE:
+        return typeVariableTypeToIr(type);
+
+      case TypeKind.MALFORMED_TYPE:
+        return const ir.InvalidType();
+
+      case TypeKind.DYNAMIC:
+        return const ir.DynamicType();
+
+      case TypeKind.VOID:
+        return const ir.VoidType();
+    }
+  }
+
+  ir.DartType typeLiteralToIr(TypeConstantExpression constant) {
+    return typeToIr(constant.type);
+  }
+
+  void setParent(ir.Member member, Element element) {
+    if (element.isLocal) {
+      member.parent = elementToIr(element.enclosingElement);
+    } else if (element.isTopLevel) {
+      member.parent = elementToIr(element.library);
+    } else if (element.isClassMember) {
+      member.parent = elementToIr(element.enclosingClass);
+    } else {
+      member.parent = elementToIr(element.enclosingElement);
+    }
+  }
+
+  bool isNativeMethod(FunctionElement element) {
+    // This method is a (modified) copy of the same method in
+    // `pkg/compiler/lib/src/native/enqueue.dart`.
+    if (!compiler.backend.canLibraryUseNative(element.library)) return false;
+    return compiler.reporter.withCurrentElement(element, () {
+      FunctionExpression functionExpression =
+          element.node?.asFunctionExpression();
+      if (functionExpression == null) return false;
+      Node body = functionExpression.body;
+      if (body == null) return false;
+      if (identical(body.getBeginToken().stringValue, 'native')) return true;
+      return false;
+    });
+  }
+
+  ir.Member functionToIr(FunctionElement function) {
+    if (function.isDeferredLoaderGetter) {
+      internalError(function, "Deferred loader.");
+    }
+    if (function.isLocal) {
+      internalError(function, "Local function.");
+    }
+    if (isSyntheticError(function)) {
+      internalError(function, "Synthetic error function: $function.");
+    }
+    function = function.declaration;
+    return functions.putIfAbsent(function, () {
+      function = function.implementation;
+      ir.Member member;
+      ir.Constructor constructor;
+      ir.Procedure procedure;
+      ir.Name name = irName(function.name, function);
+      bool isNative = isNativeMethod(function);
+      if (function.isGenerativeConstructor) {
+        member = constructor = new ir.Constructor(null,
+            name: name,
+            isConst: function.isConst,
+            isExternal: isNative || function.isExternal,
+            initializers: null);
+      } else {
+        member = procedure = new ir.Procedure(name, null, null,
+            isAbstract: function.isAbstract,
+            isStatic: function.isStatic ||
+                function.isTopLevel ||
+                function.isFactoryConstructor,
+            isExternal: isNative || function.isExternal,
+            isConst: false); // TODO(ahe): When is this true?
+      }
+      addWork(function, () {
+        setParent(member, function);
+        KernelVisitor visitor =
+            new KernelVisitor(function, function.treeElements, this);
+        beginFactoryScope(function);
+        IrFunction irFunction = visitor.buildFunction();
+        // TODO(ahe): Add addFunction/set function to [ir.Procedure].
+        irFunction.node.parent = member;
+        if (irFunction.isConstructor) {
+          assert(irFunction.kind == null);
+          constructor.function = irFunction.node;
+          constructor.initializers = irFunction.initializers;
+          // TODO(ahe): Add setInitializers to [ir.Constructor].
+          for (ir.Initializer initializer in irFunction.initializers) {
+            initializer.parent = constructor;
+          }
+          moveSuperCallLast(constructor);
+        } else {
+          assert(irFunction.kind != null);
+          procedure.function = irFunction.node;
+          procedure.kind = irFunction.kind;
+        }
+        endFactoryScope(function);
+        assert(() {
+          visitor.locals.forEach(checkMember);
+          return true;
+        });
+      });
+      return member;
+    });
+  }
+
+  /// Adds the type parameters of the enclosing class of [function] to
+  /// [factoryTypeParameters]. This serves as a local scope for type variables
+  /// resolved inside the factory.
+  ///
+  /// This method solves the problem that a factory method really is a generic
+  /// method that has its own type parameters, one for each type parameter in
+  /// the enclosing class.
+  void beginFactoryScope(FunctionElement function) {
+    assert(factoryTypeParameters.isEmpty);
+    if (!function.isFactoryConstructor) return;
+    ClassElement cls = function.enclosingClass;
+    for (DartType type in cls.typeVariables) {
+      if (type.isTypeVariable) {
+        TypeVariableElement variable = type.element;
+        factoryTypeParameters[variable] =
+            new ir.TypeParameter(variable.name, null);
+      }
+    }
+    for (DartType type in cls.typeVariables) {
+      if (type.isTypeVariable) {
+        TypeVariableElement variable = type.element;
+        factoryTypeParameters[variable].bound = typeToIr(variable.bound);
+      }
+    }
+  }
+
+  /// Ends the local scope started by [beginFactoryScope].
+  void endFactoryScope(FunctionElement function) {
+    factoryTypeParameters.clear();
+  }
+
+  ir.Field fieldToIr(FieldElement field) {
+    if (isSyntheticError(field)) {
+      internalError(field, "Synthetic error field: $field.");
+    }
+    field = field.declaration;
+    return fields.putIfAbsent(field, () {
+      field = field.implementation;
+      ir.DartType type =
+          field.isMalformed ? const ir.InvalidType() : typeToIr(field.type);
+      ir.Field fieldNode = new ir.Field(irName(field.memberName.text, field),
+          type: type,
+          initializer: null,
+          isFinal: field.isFinal,
+          isStatic: field.isStatic || field.isTopLevel,
+          isConst: field.isConst);
+      addWork(field, () {
+        setParent(fieldNode, field);
+        if (!field.isMalformed &&
+            !field.isInstanceMember &&
+            field.initializer != null) {
+          KernelVisitor visitor =
+              new KernelVisitor(field, field.treeElements, this);
+          fieldNode.initializer = visitor.buildInitializer()
+            ..parent = fieldNode;
+        }
+      });
+      return fieldNode;
+    });
+  }
+
+  ir.TypeParameter typeVariableToIr(TypeVariableElement variable) {
+    variable = variable.declaration;
+    ir.TypeParameter parameter = factoryTypeParameters[variable];
+    if (parameter != null) return parameter;
+    return typeParameters.putIfAbsent(variable, () {
+      ir.TypeParameter parameter = new ir.TypeParameter(variable.name, null);
+      addWork(variable, () {
+        // TODO(ahe): This assignment will probably not be correct when dart2js
+        // supports generic methods.
+        ClassElement cls = variable.typeDeclaration;
+        parameter.parent = classToIr(cls);
+        parameter.bound = typeToIr(variable.bound);
+      });
+      return parameter;
+    });
+  }
+
+  List<ir.TypeParameter> typeVariablesToIr(List<DartType> variables) {
+    List<ir.TypeParameter> result =
+        new List<ir.TypeParameter>(variables.length);
+    for (int i = 0; i < variables.length; i++) {
+      TypeVariableType type = variables[i];
+      result[i] = typeVariableToIr(type.element);
+    }
+    return result;
+  }
+
+  ir.TreeNode elementToIr(Element element) {
+    if (element.isLibrary) return libraryToIr(element);
+    if (element.isClass) return classToIr(element);
+    if (element.isFunction || element.isAccessor) return functionToIr(element);
+    if (element.isField) return fieldToIr(element);
+    throw "unhandled element: $element";
+  }
+
+  void debugMessage(Spannable spannable, String message) {
+    compiler.reporter
+        .reportHintMessage(spannable, MessageKind.GENERIC, {'text': message});
+  }
+
+  void internalError(Spannable spannable, String message) {
+    compiler.reporter.internalError(spannable, message);
+    throw message;
+  }
+
+  ConstructorTarget computeEffectiveTarget(
+      ConstructorElement constructor, DartType type) {
+    constructor = constructor.implementation;
+    Set<ConstructorElement> seen = new Set<ConstructorElement>();
+    functionToIr(constructor);
+    while (constructor != constructor.effectiveTarget) {
+      type = constructor.computeEffectiveTargetType(type);
+      if (constructor.isGenerativeConstructor) break;
+      if (!seen.add(constructor)) break;
+      constructor = constructor.effectiveTarget.implementation;
+      if (isSyntheticError(constructor)) break;
+      functionToIr(constructor);
+    }
+    return new ConstructorTarget(constructor, type);
+  }
+
+  /// Returns true if [element] is synthesized to recover or represent a
+  /// semantic error, for example, missing, duplicated, or ambiguous elements.
+  /// However, returns false for elements that have an unrecoverable syntax
+  /// error. Both kinds of element will return true from [Element.isMalformed],
+  /// but they must be handled differently. For example, a static call to
+  /// synthetic error element should be compiled to [ir.InvalidExpression],
+  /// whereas a static call to a method which has a syntax error should be
+  /// compiled to a static call to the method. The method itself will have a
+  /// method body that is [ir.InvalidStatement].
+  bool isSyntheticError(Element element) {
+    if (element.isAmbiguous) return true;
+    if (element.isError) return true;
+    if (element.isField && element is ErroneousFieldElementX) {
+      return true;
+    }
+    return false;
+  }
+
+  ir.Procedure getDartCoreMethod(String name) {
+    LibraryElement library =
+        compiler.libraryLoader.lookupLibrary(Uri.parse("dart:core"));
+    Element function = library.implementation.localLookup(name);
+    return functionToIr(function);
+  }
+
+  ir.Procedure getMalformedTypeErrorBuilder() {
+    return getDartCoreMethod('_malformedTypeError');
+  }
+
+  ir.Procedure getUnresolvedConstructorBuilder() {
+    return getDartCoreMethod('_unresolvedConstructorError');
+  }
+
+  ir.Procedure getUnresolvedStaticGetterBuilder() {
+    return getDartCoreMethod('_unresolvedStaticGetterError');
+  }
+
+  ir.Procedure getUnresolvedStaticSetterBuilder() {
+    return getDartCoreMethod('_unresolvedStaticSetterError');
+  }
+
+  ir.Procedure getUnresolvedStaticMethodBuilder() {
+    return getDartCoreMethod('_unresolvedStaticMethodError');
+  }
+
+  ir.Procedure getUnresolvedTopLevelGetterBuilder() {
+    return getDartCoreMethod('_unresolvedTopLevelGetterError');
+  }
+
+  ir.Procedure getUnresolvedTopLevelSetterBuilder() {
+    return getDartCoreMethod('_unresolvedTopLevelSetterError');
+  }
+
+  ir.Procedure getUnresolvedTopLevelMethodBuilder() {
+    return getDartCoreMethod('_unresolvedTopLevelMethodError');
+  }
+
+  ir.Procedure getUnresolvedSuperGetterBuilder() {
+    return getDartCoreMethod('_unresolvedSuperGetterError');
+  }
+
+  ir.Procedure getUnresolvedSuperSetterBuilder() {
+    return getDartCoreMethod('_unresolvedSuperSetterError');
+  }
+
+  ir.Procedure getUnresolvedSuperMethodBuilder() {
+    return getDartCoreMethod('_unresolvedSuperMethodError');
+  }
+
+  ir.Procedure getGenericNoSuchMethodBuilder() {
+    return getDartCoreMethod('_genericNoSuchMethod');
+  }
+
+  ir.Procedure getFallThroughErrorBuilder() {
+    return getDartCoreMethod('_fallThroughError');
+  }
+}
+
+class ConstructorTarget {
+  final ConstructorElement element;
+  final DartType type;
+
+  ConstructorTarget(this.element, this.type);
+
+  String toString() => "ConstructorTarget($element, $type)";
+}