Collect debugging info for catch clauses

runtime/vm/parser.cc

Index: runtime/vm/parser.cc
===================================================================
--- runtime/vm/parser.cc	(revision 17032)
+++ runtime/vm/parser.cc	(working copy)
@@ -5969,6 +5969,8 @@
   const intptr_t handler_pos = TokenPos();
   OpenBlock();  // Start the catch block sequence.
   current_block_->scope->AddLabel(end_catch_label);
+  const GrowableObjectArray& handler_types =
+      GrowableObjectArray::Handle(GrowableObjectArray::New());
   while ((CurrentToken() == Token::kCATCH) || IsLiteral("on")) {
     const intptr_t catch_pos = TokenPos();
     CatchParamDesc exception_param;
@@ -6061,11 +6063,17 @@
           catch_pos, Token::kIS, exception_var, exception_type);
       current_block_->statements->Add(
           new IfNode(catch_pos, type_cond_expr, catch_handler, NULL));
+      ASSERT(exception_type->type().IsInstantiated());
+      handler_types.Add(*exception_param.type);
     } else {
       // No exception type exists in the catch specifier so execute the
       // catch handler code unconditionally.
       current_block_->statements->Add(catch_handler);
       generic_catch_seen = true;
+      // This catch clause will handle all exceptions. We can safely forget
+      // all previous catch clause types.
+      handler_types.SetLength(0);
+      handler_types.Add(*exception_param.type);

[siva, 2013/01/15 22:04:12]

We should also be ok to not collect any more catch clause types from this point
on right?

e.g:
try {
  ...
  ....
}
on type1 catch() { ... }
catch() { ... }
on type2 catch() { ... }

I know this code looks weird but I assume is still legal.

[hausner, 2013/01/15 22:44:52]

The compiler prints an error message if there are any more catch clauses after a
catch clause that catches type 'dynamic'. So, essentially we can never have a
case where we collect more types since this has to be the last catch clause we
see.

     }
     SequenceNode* catch_clause = CloseBlock();
 
@@ -6118,11 +6126,13 @@
                       new LoadLocalNode(handler_pos, catch_excp_var),
                       new LoadLocalNode(handler_pos, catch_trace_var)));
   }
-  CatchClauseNode* catch_block = new CatchClauseNode(handler_pos,
-                                                     catch_handler_list,
-                                                     context_var,
-                                                     catch_excp_var,
-                                                     catch_trace_var);
+  CatchClauseNode* catch_block =
+      new CatchClauseNode(handler_pos,
+                          catch_handler_list,
+                          Array::ZoneHandle(Array::MakeArray(handler_types)),
+                          context_var,
+                          catch_excp_var,
+                          catch_trace_var);
 
   // Now create the try/catch ast node and return it. If there is a label
   // on the try/catch, close the block that's embedding the try statement