Precompilation:

runtime/bin/main.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 <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 
 #include "include/dart_api.h"
 #include "include/dart_tools_api.h"
@@ skipping 794 matching lines @@
     return isolate;
   }
 #endif  // defined(DART_PRODUCT_BINARY)
 
   // Prepare builtin and other core libraries for use to resolve URIs.
   // Set up various closures, e.g: printing, timers etc.
   // Set up 'package root' for URI resolution.
   result = DartUtils::PrepareForScriptLoading(false, trace_loading);
   CHECK_RESULT(result);
 
-  if (run_service_isolate) {
+  if (!run_precompiled_snapshot && !run_full_snapshot) {
     // Set up the load port provided by the service isolate so that we can
     // load scripts.
+    // With a full snapshot or a precompiled snapshot in product mode, there is
+    // no service isolate. A precompiled snapshot in release or debug mode does
+    // have the service isolate, but it doesn't use it for loading.
     result = DartUtils::SetupServiceLoadPort();
     CHECK_RESULT(result);
   }
 
   // Setup package root if specified.
   result = DartUtils::SetupPackageRoot(package_root, packages_config);
   CHECK_RESULT(result);
 
   result = Dart_SetEnvironmentCallback(EnvironmentCallback);
   CHECK_RESULT(result);
@@ skipping 869 matching lines @@
   Platform::Exit(Process::GlobalExitCode());
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   dart::bin::main(argc, argv);
   UNREACHABLE();
 }