Fix async machinery (issue 22445 and possibly others to be triaged later).

runtime/vm/flow_graph_builder.cc

 // 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.
 
 #include "vm/flow_graph_builder.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/class_finalizer.h"
@@ skipping 4074 matching lines @@
   if (finally_block != NULL) {
     // Create a handler for the code in the catch block, containing the
     // code in the finally block.
     owner()->set_try_index(original_handler_index);
     EffectGraphVisitor for_finally(owner());
     for_finally.BuildRestoreContext(catch_block->context_var());
 
     finally_block->Visit(&for_finally);
     if (for_finally.is_open()) {
       // Rethrow the exception.  Manually build the graph for rethrow.
+      // TODO(regis): This is not correct. Issue 22595.
       Value* exception = for_finally.Bind(
           for_finally.BuildLoadLocal(catch_block->exception_var()));
       for_finally.PushArgument(exception);
       Value* stacktrace = for_finally.Bind(
           for_finally.BuildLoadLocal(catch_block->stacktrace_var()));
       for_finally.PushArgument(stacktrace);
       for_finally.AddInstruction(
           new(I) ReThrowInstr(catch_block->token_pos(), catch_handler_index));
       for_finally.CloseFragment();
     }
@@ skipping 252 matching lines @@
   Report::MessageF(Report::kBailout,
                    Script::Handle(function.script()),
                    function.token_pos(),
                    "FlowGraphBuilder Bailout: %s %s",
                    String::Handle(function.name()).ToCString(),
                    reason);
   UNREACHABLE();
 }
 
 }  // namespace dart