Implement redirecting constructors.

dart/sdk/lib/_internal/compiler/implementation/ssa/builder.dart

 // Copyright (c) 2012, 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.
 
 part of ssa;
 
 class Interceptors {
   Compiler compiler;
   Interceptors(Compiler this.compiler);
 
@@ skipping 3055 matching lines @@
         return HType.UNKNOWN;
       }
     }
 
     Element constructor = elements[node];
     Selector selector = elements.getSelector(node);
     if (compiler.enqueuer.resolution.getCachedElements(constructor) == null) {
       compiler.internalError("Unresolved element: $constructor", node: node);
     }
     FunctionElement functionElement = constructor;
-    constructor = functionElement.defaultImplementation;
+    constructor = functionElement.redirectionTarget;
     // TODO(5346): Try to avoid the need for calling [declaration] before
     // creating an [HStatic].
     HInstruction target = new HStatic(constructor.declaration);
     add(target);
     var inputs = <HInstruction>[];
     inputs.add(target);
     // TODO(5347): Try to avoid the need for calling [implementation] before
     // calling [addStaticSendArgumentsToList].
     bool succeeded = addStaticSendArgumentsToList(selector, node.arguments,
                                                   constructor.implementation,
@@ skipping 213 matching lines @@
       existingArguments.add(parameter.name.slowToString());
     });
     generateThrowNoSuchMethod(diagnosticNode,
                               function.name.slowToString(),
                               argumentNodes: argumentNodes,
                               existingArguments: existingArguments);
   }
 
   visitNewExpression(NewExpression node) {
     Element element = elements[node.send];
+    if (!Elements.isErroneousElement(element)) {
+      element = element.redirectionTarget;
+    }
     if (Elements.isErroneousElement(element)) {
       ErroneousElement error = element;
       if (error.messageKind == MessageKind.CANNOT_FIND_CONSTRUCTOR) {
         generateThrowNoSuchMethod(node.send,
                                   getTargetName(error, 'constructor'),
                                   argumentNodes: node.send.arguments);
       } else if (error.messageKind == MessageKind.CANNOT_RESOLVE) {
         Message message = error.messageKind.message(error.messageArguments);
         generateRuntimeError(node.send, message.toString());
       } else {
@@ skipping 196 matching lines @@
     HBasicBlock newBlock = graph.addNewBlock();
     block.addSuccessor(newBlock);
     open(newBlock);
   }
 
   visitReturn(Return node) {
     if (identical(node.getBeginToken().stringValue, 'native')) {
       native.handleSsaNative(this, node.expression);
       return;
     }
-    if (node.isRedirectingFactoryBody) {
-      compiler.internalError("Unimplemented: Redirecting factory constructor",
-                             node: node);
-    }
+    assert(invariant(node, !node.isRedirectingFactoryBody));
     HInstruction value;
     if (node.expression == null) {
       value = graph.addConstantNull(constantSystem);
     } else {
       visit(node.expression);
       value = pop();
       if (value is HForeign) {
         // TODO(6530, 6534): remove this check.
       } else {
         value = potentiallyCheckType(value, returnType);
@@ skipping 1231 matching lines @@
           new HSubGraphBlockInformation(elseBranch.graph));
 
     HBasicBlock conditionStartBlock = conditionBranch.block;
     conditionStartBlock.setBlockFlow(info, joinBlock);
     SubGraph conditionGraph = conditionBranch.graph;
     HIf branch = conditionGraph.end.last;
     assert(branch is HIf);
     branch.blockInformation = conditionStartBlock.blockFlow;
   }
 }