Support top-level field declaration and assignment in analyzer2dart.

pkg/compiler/lib/src/cps_ir/cps_ir_builder.dart

 // Copyright (c) 2013, 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.ir_builder;
 
 import '../constants/expressions.dart';
 import '../constants/values.dart' show PrimitiveConstantValue;
 import '../dart_backend/dart_backend.dart' show DartBackend;
 import '../dart_types.dart';
@@ skipping 129 matching lines @@
   /// Execute [f] with [builder] as the current builder.
   withBuilder(IrBuilder builder, f()) {
     assert(builder != null);
     IrBuilder prev = _irBuilder;
     _irBuilder = builder;
     var result = f();
     _irBuilder = prev;
     return result;
   }
 
+  /// `true` if an [IrBuilder] is currently set up.
+  bool get hasIrBuilder => _irBuilder != null;
+
   /// The current builder.
   IrBuilder get irBuilder {
     assert(_irBuilder != null);
     return _irBuilder;
   }
 
   /// Visits the [node].
   ir.Primitive visit(N node);
 
   /// Builds and returns the [ir.Node] for [node] or returns `null` if
@@ skipping 367 matching lines @@
    * such as `foo(){ }`.
    */
   void _ensureReturn() {
     if (!isOpen) return;
     ir.Constant constant = buildNullLiteral();
     add(new ir.InvokeContinuation(state.returnContinuation, [constant]));
     _current = null;
   }
 
   /// Create a [ir.FieldDefinition] for the current [Element] using [_root] as
-  /// the body.
-  ir.FieldDefinition makeFieldDefinition() {
-    return new ir.FieldDefinition(state.currentElement,
-                                  state.returnContinuation,
-                                  _root);
+  /// the body using [initializer] as the initial value.
+  ir.FieldDefinition makeFieldDefinition(ir.Primitive initializer) {
+    if (initializer == null) {
+      return new ir.FieldDefinition.withoutInitializer(state.currentElement);
+    } else {
+      buildReturn(initializer);
+      return new ir.FieldDefinition(state.currentElement,
+                                    state.returnContinuation,
+                                    _root);
+    }
   }
 
   /// Create a [ir.FunctionDefinition] for [element] using [_root] as the body.
   ///
   /// Parameters must be created before the construction of the body using
   /// [createParameter].
-  ir.FunctionDefinition buildFunctionDefinition(
+  ir.FunctionDefinition makeFunctionDefinition(
       List<ConstantExpression> defaults) {
     FunctionElement element = state.currentElement;
     if (element.isAbstract || element.isExternal) {
       assert(invariant(element, _root == null,
           message: "Non-empty body for abstract method $element: $_root"));
       assert(invariant(element, state.localConstants.isEmpty,
           message: "Local constants for abstract method $element: "
                    "${state.localConstants}"));
       return new ir.FunctionDefinition.abstract(
                 element, _parameters, defaults);
@@ skipping 903 matching lines @@
     index = 0;
     for (int i = 0; i < environment.length; ++i) {
       if (common[i] == null) {
         environment.index2value[i] = parameters[index++];
       }
     }
 
     return join;
   }
 }