Implement cascaded calls.

lib/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.
 
 class Interceptors {
   Compiler compiler;
   Interceptors(Compiler this.compiler);
 
   SourceString mapOperatorToMethodName(Operator op) {
     String name = op.source.stringValue;
@@ skipping 1001 matching lines @@
 
   void push(HInstruction instruction) {
     add(instruction);
     stack.add(instruction);
   }
 
   HInstruction pop() {
     return stack.removeLast();
   }
 
+  void dup() {
+    stack.add(stack.last());
+  }
+
   HBoolify popBoolified() {
     HBoolify boolified = new HBoolify(pop());
     add(boolified);
     return boolified;
   }
 
   void visit(Node node) {
     if (node !== null) node.accept(this);
   }
 
@@ skipping 1259 matching lines @@
 
   void visitParenthesizedExpression(ParenthesizedExpression node) {
     visit(node.expression);
   }
 
   visitOperator(Operator node) {
     // Operators are intercepted in their surrounding Send nodes.
     unreachable();
   }
 
+  visitCascade(Cascade node) {
+    visit(node.expression);
+    // Remove the result and reveal the duplicated receiver on the stack.
+    pop();
+  }
+
+  visitCascadeReceiver(CascadeReceiver node) {
+    visit(node.expression);
+    dup();
+  }
+
   visitReturn(Return node) {
     HInstruction value;
     if (node.expression === null) {
       value = graph.addConstantNull();
     } else {
       visit(node.expression);
       value = pop();
     }
     close(new HReturn(value)).addSuccessor(graph.exit);
   }
@@ skipping 713 matching lines @@
                                         false,
                                         <HInstruction>[target, input]));
     return builder.pop();
   }
 
   HInstruction result() {
     flushLiterals();
     return prefix;
   }
 }