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

frog/leg/ssa/codegen.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 SsaCodeGeneratorTask extends CompilerTask {
   SsaCodeGeneratorTask(Compiler compiler) : super(compiler);
   String get name() => 'SSA code generator';
 
   String generate(WorkItem work, HGraph graph) {
     return measure(() {
@@ skipping 202 matching lines @@
 
   visitBasicBlock(HBasicBlock node) {
     currentBlock = node;
 
     // While loop will be closed by the conditional loop-branch.
     // TODO(floitsch): HACK HACK HACK.
     if (currentBlock.isLoopHeader()) beginLoop(node);
 
     HInstruction instruction = node.first;
     while (instruction != null) {
-      if (instruction is HGoto || instruction is HExit) {
+      if (instruction is HGoto || instruction is HExit || instruction is HTry) {
         visit(instruction);
         return;
       } else if (!instruction.generateAtUseSite()) {
         if (instruction is !HIf && instruction is !HBailoutTarget) {
           addIndentation();
         }
         if (instruction.usedBy.isEmpty() || instruction is HLocal) {
           visit(instruction);
         } else {
           define(instruction);
@@ skipping 109 matching lines @@
     // is responsible for visiting the successor.
     if (dominated.isEmpty()) return;
     if (dominated.length > 2) unreachable();
     if (dominated.length == 2 && currentBlock !== currentGraph.entry) {
       unreachable();
     }
     assert(dominated[0] == currentBlock.successors[0]);
     visitBasicBlock(dominated[0]);
   }
 
+  visitTry(HTry node) {
+    addIndentation();
+    buffer.add('try {\n');
+    indent++;
+    List<HBasicBlock> successors = node.block.successors;
+    visitBasicBlock(successors[0]);
+    indent--;
+
+    if (node.finallyBlock != successors[1]) {
+      addIndentation();
+      buffer.add('} catch (e) {\n');
+      indent++;
+    }
+
+    for (int i = 1; i < successors.length - 1; i++) {
+      // TODO(ngeoffray): add the type check.
+      visitBasicBlock(successors[i]);
+    }
+
+    if (node.finallyBlock == null) {
+      // TODO(ngeoffray): add the type check.
+      visitBasicBlock(successors[successors.length - 1]);
+    } else {
+      addIndentation();
+      buffer.add('} finally {\n');
+      indent++;
+      visitBasicBlock(node.finallyBlock);
+    }
+    indent--;
+    addIndentation();
+    buffer.add('}\n');
+  }
+
   visitIf(HIf node) {
     startIf(node);
     assert(!node.generateAtUseSite());
     startThen(node);
     visitBasicBlock(node.thenBlock);
     endThen(node);
     if (node.hasElse) {
       startElse(node);
       visitBasicBlock(node.elseBlock);
       endElse(node);
@@ skipping 107 matching lines @@
       buffer.add('.');
     }
     String name = JsNames.getValid('${node.element.name}');
     buffer.add(name);
   }
 
   visitFieldSet(HFieldSet node) {
     if (node.receiver != null) {
       use(node.receiver);
       buffer.add('.');
+    } else {
+      // TODO(ngeoffray): Remove the 'var' once we don't globally box
+      // variables used in a try/catch.
+      buffer.add('var ');
     }
     String name = JsNames.getValid('${node.element.name}');
     buffer.add(name);
     buffer.add(' = ');
     use(node.value);
   }
 
   visitForeign(HForeign node) {
     String code = '${node.code}';
     List<HInstruction> inputs = node.inputs;
@@ skipping 621 matching lines @@
       startBailoutSwitch();
     }
   }
 
   void endElse(HIf node) {
     if (node.elseBlock.hasBailouts()) {
       endBailoutSwitch();
     }
   }
 }