VM: [Kernel] Fix bootstraping when Kernel isolate is used.

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 16 matching lines @@
       error_(Dart_Null()),
       monitor_(NULL),
       pending_operations_(0),
       results_(NULL),
       results_length_(0),
       results_capacity_(0),
       payload_(NULL),
       payload_length_(0) {
   monitor_ = new Monitor();
   ASSERT(isolate_data_ != NULL);
-  port_ = Dart_NewNativePort("Loader", Loader::NativeMessageHandler, false);
+  port_ =
+      Dart_NewNativePort("Loader", Loader::NativeMessageHandler, false, this);
   isolate_data_->set_loader(this);
   AddLoader(port_, isolate_data_);
 }
 
 
 Loader::~Loader() {
   ASSERT(port_ != ILLEGAL_PORT);
   // Enter the monitor while we close the Dart port. After the Dart port is
   // closed, no more results can be queued.
   monitor_->Enter();
@@ skipping 589 matching lines @@
     // Use the existing loader.
     loader = isolate_data->loader();
   }
   ASSERT(loader != NULL);
   ASSERT(isolate_data->HasLoader());
 
   if (DartUtils::IsDartExtensionSchemeURL(url_string)) {
     loader->SendImportExtensionRequest(url, Dart_LibraryUrl(library));
   } else {
     if (Dart_KernelIsolateIsRunning()) {
       loader->SendKernelRequest(tag, url);

[hausner, 2017/01/24 00:50:55]

Is this code path still used? It seems to me that it is not, and if so, it
should be removed.

[Vyacheslav Egorov (Google), 2017/01/30 19:34:12]

This code path will be used again when we start doing things like deferred
library support. I think we should keep it in for now.

     } else {
       loader->SendRequest(tag, url, (library != Dart_Null())
                                         ? Dart_LibraryUrl(library)
                                         : Dart_Null());
     }
   }
 
   if (blocking_call) {
     // The outer invocation of the tag handler will block here until all nested
     // invocations complete.
@@ skipping 152 matching lines @@
 }
 
 
 Loader* Loader::LoaderFor(Dart_Port port) {
   MutexLocker ml(loader_infos_lock_);
   return LoaderForLocked(port);
 }
 
 
 void Loader::NativeMessageHandler(Dart_Port dest_port_id,
-                                  Dart_CObject* message) {
+                                  Dart_CObject* message,
+                                  void* peer) {
   MutexLocker ml(loader_infos_lock_);
-  Loader* loader = LoaderForLocked(dest_port_id);
-  if (loader == NULL) {
-    return;
-  }
-  loader->QueueMessage(message);
+  static_cast<Loader*>(peer)->QueueMessage(message);
 }
 
 }  // namespace bin
 }  // namespace dart