Implement try/catch without finally, and without type checks.

frog/leg/ssa/tracer.dart

 // Copyright (c) 2011, 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 HTracer extends HGraphVisitor {
   int indent = 0;
   final StringBuffer output;
 
   factory HTracer.singleton() {
     if (_singleton === null) _singleton = new HTracer._internal();
@@ skipping 364 matching lines @@
   String visitSubtract(HSubtract node) => visitInvokeStatic(node);
 
   String visitThis(HThis node) => "this";
 
   String visitThrow(HThrow node) => "Throw ${temporaryId(node.inputs[0])}";
 
   String visitTruncatingDivide(HTruncatingDivide node) {
     return visitInvokeStatic(node);
   }
 
+  String visitTry(HTry node) {
+    List<HBasicBlock> successors = currentBlock.successors;
+    String tryBlock = 'B${successors[0].id}';
+    StringBuffer catchBlocks = new StringBuffer();
+    for (int i = 1; i < successors.length - 1; i++) {
+      catchBlocks.add('B${successors[i].id}, ');
+    }
+
+    String finallyBlock;
+    if (node.finallyBlock != null) {
+      finallyBlock = 'B${node.finallyBlock.id}';
+    } else {
+      catchBlocks.add('B${successors[successors.length - 1].id}');
+      finallyBlock = 'none';
+    }
+    return "Try: $tryBlock, Catch: $catchBlocks, Finally: $finallyBlock";
+  }
+
   String visitTypeGuard(HTypeGuard node) {
     String type;
     switch (node.type) {
       case HType.ARRAY: type = "array"; break;
       case HType.BOOLEAN: type = "bool"; break;
       case HType.INTEGER: type = "integer"; break;
       case HType.DOUBLE: type = "double"; break;
       case HType.NUMBER: type = "number"; break;
       case HType.STRING: type = "string"; break;
       case HType.STRING_OR_ARRAY: type = "string_or_array"; break;
       default: unreachable();
     }
     return "TypeGuard: ${temporaryId(node.inputs[0])} is $type";
   }
 
   String visitIs(HIs node) {
     String type = node.typeExpression.toString();
     return "TypeTest: ${temporaryId(node.expression)} is $type";
   }
 }