Restructure code to enable reloading when a kernel dill file is specified on the command line inste…

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/dfe.h"
@@ skipping 632 matching lines @@
 Dart_Handle Loader::LibraryTagHandler(Dart_LibraryTag tag,
                                       Dart_Handle library,
                                       Dart_Handle url) {
   if (tag == Dart_kCanonicalizeUrl) {
     Dart_Handle library_url = Dart_LibraryUrl(library);
     if (Dart_IsError(library_url)) {
       return library_url;
     }
     return Dart_DefaultCanonicalizeUrl(library_url, url);
   }
-  if (dfe.UseDartFrontend()) {
-    Dart_Isolate current = Dart_CurrentIsolate();
-    if (!Dart_IsServiceIsolate(current) && !Dart_IsKernelIsolate(current)) {
-      // When using DFE the library tag handler should be called only when we
-      // are reloading scripts.
-      ASSERT(tag == Dart_kScriptTag);
-      return dfe.ReloadScript(current, url);
-    }
-    // TODO(asiva) We need to ensure that the kernel and service isolates
-    // are always loaded from a kernel IR and do not use this path.
-  }
   const char* url_string = NULL;
   Dart_Handle result = Dart_StringToCString(url, &url_string);
   if (Dart_IsError(result)) {
     return result;
   }
-
-  // Special case for handling dart: imports and parts.
-  if (tag != Dart_kScriptTag) {
+  if (tag == Dart_kScriptTag) {
+    if (dfe.UseDartFrontend()) {
+      Dart_Isolate current = Dart_CurrentIsolate();
+      // Check if we are trying to reload a kernel file or if the '--dfe'
+      // option was specified and we need to compile sources using DFE.
+      if (!Dart_IsServiceIsolate(current) && !Dart_IsKernelIsolate(current)) {
+        // When using DFE the library tag handler should be called only when
+        // we are reloading scripts.
+        return dfe.ReloadScript(current, url_string);
+      }
+    }
+    // TODO(asiva) We need to ensure that the kernel and service isolates
+    // are always loaded from a kernel IR and do not use this path.
+  } else {
+    // Special case for handling dart: imports and parts.
     // Grab the library's url.
     Dart_Handle library_url = Dart_LibraryUrl(library);
     if (Dart_IsError(library_url)) {
       return library_url;
     }
     const char* library_url_string = NULL;
     result = Dart_StringToCString(library_url, &library_url_string);
     if (Dart_IsError(result)) {
       return result;
     }
@@ skipping 242 matching lines @@
   MutexLocker ml(loader_infos_lock_);
   Loader* loader = LoaderForLocked(dest_port_id);
   if (loader == NULL) {
     return;
   }
   loader->QueueMessage(message);
 }
 
 }  // namespace bin
 }  // namespace dart