Enable causal stacktrace in kernel

runtime/vm/kernel_reader.cc

 // Copyright (c) 2016, 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/kernel_reader.h"
 
 #include <string.h>
 
 #include "vm/dart_api_impl.h"
 #include "vm/longjump.h"
@@ skipping 409 matching lines @@
   dart::Function& function = dart::Function::ZoneHandle(
       Z, Function::New(name, GetFunctionType(kernel_procedure),
                        !is_method,  // is_static
                        false,       // is_const
                        is_abstract, is_external,
                        native_name != NULL,  // is_native
                        script_class, kernel_procedure->position()));
   function.set_end_token_pos(kernel_procedure->end_position());
   owner.AddFunction(function);
   function.set_kernel_function(kernel_procedure);
-  function.set_is_debuggable(kernel_procedure->function()->debuggable());
+  function.set_is_debuggable(
+      kernel_procedure->function()->original_async_marker() ==
+      FunctionNode::kSync);
+  switch (kernel_procedure->function()->original_async_marker()) {
+    case FunctionNode::kSyncStar:
+      function.set_modifier(RawFunction::kSyncGen);
+      break;
+    case FunctionNode::kAsync:
+      function.set_modifier(RawFunction::kAsync);
+      break;
+    case FunctionNode::kAsyncStar:
+      function.set_modifier(RawFunction::kAsyncGen);
+      break;
+    default:
+      // no special modifier
+      break;
+  }
   if (native_name != NULL) {
     function.set_native_name(*native_name);
   }
 
   SetupFunctionParameters(H, T, owner, function, kernel_procedure->function(),
                           is_method,
                           false);  // is_closure
 
   if (kernel_klass == NULL) {
     library.AddObject(function, name);
@@ skipping 357 matching lines @@
   initializer_fun.set_is_debuggable(false);
   initializer_fun.set_is_reflectable(false);
   initializer_fun.set_is_inlinable(false);
   return new (zone) ParsedFunction(thread, initializer_fun);
 }
 
 
 }  // namespace kernel
 }  // namespace dart
 #endif  // !defined(DART_PRECOMPILED_RUNTIME)