dart2dart: Implementation of simple try/catch.

pkg/compiler/lib/src/tree_ir/optimization/copy_propagator.dart

 // Copyright (c) 2014, 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 tree_ir.optimization;
 
 /// Eliminates moving assignments, such as w := v, by assigning directly to w
 /// at the definition of v.
 ///
 /// This compensates for suboptimal register allocation, and merges closure
@@ skipping 192 matching lines @@
 
   Statement visitWhileTrue(WhileTrue node) {
     node.body = visitBasicBlock(node.body);
     return node;
   }
 
   Statement visitWhileCondition(WhileCondition node) {
     throw "WhileCondition before LoopRewriter";
   }
 
+  Statement visitTry(Try node) {
+    node.tryBody = visitBasicBlock(node.tryBody);
+    node.catchBody = visitBasicBlock(node.catchBody);
+    return node;
+  }
+
   Statement visitFunctionDeclaration(FunctionDeclaration node) {
     // Unlike var declarations, function declarations are not hoisted, so we
     // can't do copy propagation of the variable.
     new CopyPropagator().rewrite(node.definition);
     node.next = visitStatement(node.next);
     return node;
   }
 
   Statement visitExpressionStatement(ExpressionStatement node) {
     node.next = visitStatement(node.next);
@@ skipping 10 matching lines @@
 
   void visitFunctionExpression(FunctionExpression node) {
     new CopyPropagator().rewrite(node.definition);
   }
 
   void visitFieldInitializer(FieldInitializer node) {
     visitStatement(node.body);
   }
 
 }