VM: [Kernel] Go back to previous behavior in loader.cc

runtime/bin/loader.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 "bin/loader.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 #include "bin/extensions.h"
@@ skipping 352 matching lines @@
     case Dart_kSourceTag: {
       ASSERT(library_uri != Dart_Null());
       Dart_Handle library = Dart_LookupLibrary(library_uri);
       ASSERT(!Dart_IsError(library));
       dart_result = Dart_LoadSource(library, uri, resolved_uri, source, 0, 0);
     } break;
     case Dart_kScriptTag:
       if (payload_type == DartUtils::kSnapshotMagicNumber) {
         dart_result = Dart_LoadScriptFromSnapshot(payload, payload_length);
         reload_extensions = true;
+      } else if (payload_type == DartUtils::kKernelMagicNumber) {
+        // TODO(27590): This code path is only hit when trying to spawn
+        // isolates. We currently do not have support for neither
+        // `Isolate.spawn()` nor `Isolate.spawnUri()` with kernel-based
+        // frontend.
+        void* kernel_binary = Dart_ReadKernelBinary(payload, payload_length);
+        dart_result = Dart_LoadKernel(kernel_binary);
       } else {
         dart_result = Dart_LoadScript(uri, resolved_uri, source, 0, 0);
       }
       break;
     default:
       UNREACHABLE();
   }
 
   // Re-acquire the lock before exiting the function (it was held before entry),
   loader->monitor_->Enter();
@@ skipping 410 matching lines @@
   MutexLocker ml(loader_infos_lock_);
   Loader* loader = LoaderForLocked(dest_port_id);
   if (loader == NULL) {
     return;
   }
   loader->QueueMessage(message);
 }
 
 }  // namespace bin
 }  // namespace dart