Add SemanticVisitor to dart2js.

pkg/compiler/lib/src/resolution/access_semantics.dart

+// Copyright (c) 2015, 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.
+
+// TODO(johnniwinther): Temporarily copied from analyzer2dart. Merge when
+// we shared code with the analyzer and this semantic visitor is complete.
+
+/**
+ * Code for classifying the semantics of identifiers appearing in a Dart file.
+ */
+library dart2js.access_semantics;
+
+import '../elements/elements.dart';
+import '../tree/tree.dart';
+import '../universe/universe.dart';
+
+/**
+ * Enum representing the different kinds of destinations which a property
+ * access or method or function invocation might refer to.
+ */
+enum AccessKind {
+  /**

[karlklose, 2015/02/25 12:39:38]

Please use '///' to make the comments more compact.

[Johnni Winther, 2015/03/04 11:59:39]

Done.

+   * The destination of the access is an instance method, property, or field
+   * of a class, and thus must be determined dynamically.
+   */
+  DYNAMIC_PROPERTY,
+

[karlklose, 2015/02/25 12:39:38]

I think we should split LOCAL_FUNCTION, LOCAL_VARIABLE and PARAMETER into two
cases each:
  LOCAL_xxx for a reference to a definition in the current context, and
  LOCAL_xxx for a reference to a definition in an outer context.

[Johnni Winther, 2015/03/04 11:59:39]

Added a TODO.

+  /**
+   * The destination of the access is a function that is defined locally within
+   * an enclosing function or method.
+   */
+  LOCAL_FUNCTION,
+
+  /**
+   * The destination of the access is a variable that is defined locally within
+   * an enclosing function or method.
+   */
+  LOCAL_VARIABLE,
+
+  /**
+   * The destination of the access is a variable that is defined as a parameter
+   * to an enclosing function or method.
+   */
+  PARAMETER,
+
+  /**
+   * The destination of the access is a field that is defined statically within
+   * a class, or a top level variable within a library.
+   */
+  STATIC_FIELD,
+
+  /**
+   * The destination of the access is a method that is defined statically
+   * within a class, or at top level within a library.
+   */
+  STATIC_METHOD,
+
+  /**
+   * The destination of the access is a property getter that is defined
+   * statically within a class, or at top level within a library.
+   */
+  STATIC_GETTER,
+
+  /**
+   * The destination of the access is a property setter that is defined
+   * statically within a class, or at top level within a library.
+   */
+  STATIC_SETTER,
+
+  /**
+   * The destination of the access is a field that is defined statically within
+   * a class, or a top level variable within a library.
+   */
+  TOPLEVEL_FIELD,
+
+  /**
+   * The destination of the access is a method that is defined statically
+   * within a class, or at top level within a library.
+   */
+  TOPLEVEL_METHOD,
+
+  /**
+   * The destination of the access is a property getter that is defined
+   * statically within a class, or at top level within a library.
+   */
+  TOPLEVEL_GETTER,
+
+  /**
+   * The destination of the access is a property setter that is defined
+   * statically within a class, or at top level within a library.
+   */
+  TOPLEVEL_SETTER,
+
+  /**
+   * The destination of the access is a toplevel class, or mixin application.
+   */
+  CLASS_TYPE_LITERAL,
+
+  /**
+   * The destination of the access is a function typedef.
+   */
+  TYPEDEF_TYPE_LITERAL,
+
+  /**
+   * The destination of the access is the built-in type "dynamic".
+   */
+  DYNAMIC_TYPE_LITERAL,
+
+  /**
+   * The destination of the access is a type parameter of the enclosing class.
+   */
+  TYPE_PARAMETER_TYPE_LITERAL,
+
+  /**
+   * The destination of the access is a (complex) expression. For instance the
+   * function expression `(){}` in the function expression invocation `(){}()`.
+   */
+  EXPRESSION,
+
+  /**
+   * The destination of the access is `this` of the enclosing class.
+   */
+  THIS,
+
+  /**
+   * The destination of the access is a property on the enclosing class.
+   */
+  THIS_PROPERTY,
+
+  /**
+   * The destination of the access is a field of the super class of the
+   * enclosing class.
+   */
+  SUPER_FIELD,
+
+  /**
+   * The destination of the access is a method of the super class of the
+   * enclosing class.
+   */
+  SUPER_METHOD,
+
+  /**
+   * The destination of the access is a getter of the super class of the
+   * enclosing class.
+   */
+  SUPER_GETTER,
+
+  /**
+   * The destination of the access is a setter of the super class of the
+   * enclosing class.
+   */
+  SUPER_SETTER,
+
+  /// Compound access where read and write access different elements.
+  /// See [CompoundAccessKind].
+  COMPOUND,
+}
+
+enum CompoundAccessKind {
+  /// Read from a static getter and write to static setter.
+  STATIC_GETTER_SETTER,
+  /// Read from a static method (closurize) and write to static setter.
+  STATIC_METHOD_SETTER,
+
+  /// Read from a top level getter and write to a top level setter.
+  TOPLEVEL_GETTER_SETTER,
+  /// Read from a top level method (closurize) and write to top level setter.
+  TOPLEVEL_METHOD_SETTER,
+
+  /// Read from one superclass field and write to another.
+  SUPER_FIELD_FIELD,
+  /// Read from a superclass field and write to a superclass setter.
+  SUPER_FIELD_SETTER,
+  /// Read from a superclass getter and write to a superclass setter.
+  SUPER_GETTER_SETTER,
+  /// Read from a superclass method (closurize) and write to a superclass
+  /// setter.
+  SUPER_METHOD_SETTER,
+  /// Read from a superclass getter and write to a superclass field.
+  SUPER_GETTER_FIELD,
+}
+
+/**
+ * Data structure used to classify the semantics of a property access or method
+ * or function invocation.
+ */
+class AccessSemantics {
+  /**
+   * The kind of access.
+   */
+  final AccessKind kind;
+
+  /**
+   * The element being accessed, if statically known.  This will be null if
+   * [kind] is DYNAMIC or if the element is undefined (e.g. an attempt to
+   * access a non-existent static method in a class).
+   */
+  final Element element;
+
+  /**
+   * The class containing the element being accessed, if this is a static
+   * reference to an element in a class.  This will be null if [kind] is
+   * DYNAMIC, LOCAL_FUNCTION, LOCAL_VARIABLE, PARAMETER, TOPLEVEL_CLASS, or
+   * TYPE_PARAMETER, or if the element being accessed is defined at toplevel
+   * within a library.
+   *
+   * Note: it is possible for [classElement] to be non-null and for [element]
+   * to be null; for example this occurs if the element being accessed is a
+   * non-existent static method or field inside an existing class.
+   */
+  final ClassElement classElement;
+
+  // TODO(paulberry): would it also be useful to store the libraryElement?
+
+  /**
+   * When [kind] is DYNAMIC, the expression whose runtime type determines the
+   * class in which [identifier] should be looked up.  Null if the expression

[karlklose, 2015/02/25 12:39:38]

'[Null]' or '`null`'?

[Johnni Winther, 2015/03/04 11:59:38]

Done.

+   * is implicit "this".
+   *
+   * When [kind] is not DYNAMIC, this field is always null.
+   */
+  final /*Expression*/ target;
+
+  AccessSemantics.dynamicProperty(this.target)
+      : kind = AccessKind.DYNAMIC_PROPERTY,
+        element = null,
+        classElement = null;
+
+  AccessSemantics.localFunction(this.element)
+      : kind = AccessKind.LOCAL_FUNCTION,
+        classElement = null,
+        target = null;
+
+  AccessSemantics.localVariable(this.element)
+      : kind = AccessKind.LOCAL_VARIABLE,
+        classElement = null,
+        target = null;
+
+  AccessSemantics.parameter(this.element)
+      : kind = AccessKind.PARAMETER,
+        classElement = null,
+        target = null;
+
+  AccessSemantics.staticField(this.element, this.classElement)
+      : kind = AccessKind.STATIC_FIELD,
+        target = null;
+
+  AccessSemantics.staticMethod(this.element, this.classElement)
+      : kind = AccessKind.STATIC_METHOD,
+        target = null;
+
+  AccessSemantics.staticGetter(this.element, this.classElement)
+      : kind = AccessKind.STATIC_GETTER,
+        target = null;
+
+  AccessSemantics.staticSetter(this.element, this.classElement)
+      : kind = AccessKind.STATIC_SETTER,
+        target = null;
+
+  AccessSemantics.topLevelField(this.element)
+      : kind = AccessKind.TOPLEVEL_FIELD,
+        target = null,
+        classElement = null;
+
+  AccessSemantics.topLevelMethod(this.element)
+      : kind = AccessKind.TOPLEVEL_METHOD,
+        target = null,
+        classElement = null;
+
+  AccessSemantics.topLevelGetter(this.element)
+      : kind = AccessKind.TOPLEVEL_GETTER,
+        target = null,
+        classElement = null;
+
+  AccessSemantics.topLevelSetter(this.element)
+      : kind = AccessKind.TOPLEVEL_SETTER,
+        target = null,
+        classElement = null;
+
+  AccessSemantics.classTypeLiteral(this.element)
+      : kind = AccessKind.CLASS_TYPE_LITERAL,
+        classElement = null,
+        target = null;
+
+  AccessSemantics.typedefTypeLiteral(this.element)
+      : kind = AccessKind.TYPEDEF_TYPE_LITERAL,
+        classElement = null,
+        target = null;
+
+  AccessSemantics.dynamicTypeLiteral()
+      : kind = AccessKind.DYNAMIC_TYPE_LITERAL,
+        element = null,
+        classElement = null,
+        target = null;
+
+  AccessSemantics.typeParameterTypeLiteral(this.element)
+      : kind = AccessKind.TYPE_PARAMETER_TYPE_LITERAL,
+        classElement = null,
+        target = null;
+
+  AccessSemantics.expression()
+      : kind = AccessKind.EXPRESSION,
+        element = null,
+        classElement = null,
+        target = null;
+
+  AccessSemantics.thisAccess()
+      : kind = AccessKind.THIS,
+        element = null,
+        classElement = null,
+        target = null;
+
+  AccessSemantics.thisProperty()
+      : kind = AccessKind.THIS_PROPERTY,
+        element = null,
+        classElement = null,
+        target = null;
+
+  AccessSemantics.superField(this.element)
+      : kind = AccessKind.SUPER_FIELD,
+        classElement = null,
+        target = null;
+
+  AccessSemantics.superMethod(this.element)
+      : kind = AccessKind.SUPER_METHOD,
+        classElement = null,
+        target = null;
+
+  AccessSemantics.superGetter(this.element)
+      : kind = AccessKind.SUPER_GETTER,
+        classElement = null,
+        target = null;
+
+  AccessSemantics.superSetter(this.element)
+      : kind = AccessKind.SUPER_SETTER,
+        classElement = null,
+        target = null;
+
+  AccessSemantics._compound(this.element, this.classElement)
+      : this.kind = AccessKind.COMPOUND,
+        this.target = null;
+
+  String toString() {
+    StringBuffer sb = new StringBuffer();
+    sb.write('AccessSemantics[');
+    sb.write('kind=$kind,');
+    if (element != null) {
+      sb.write('element=');
+      if (classElement != null) {
+        sb.write('${classElement.name}.');
+      }
+      sb.write('${element}');
+    }
+    sb.write(']');
+    return sb.toString();
+  }
+}
+
+class CompoundAccessSemantics extends AccessSemantics {
+  final CompoundAccessKind compoundAccessKind;
+  final Element getter;
+
+  CompoundAccessSemantics(this.compoundAccessKind,
+                          this.getter,
+                          Element setter,
+                          {ClassElement classElement})
+      : super._compound(setter, classElement);
+
+  Element get setter => element;
+}