VM: Support bootstrapping core libraries from Kernel binaries instead of source.

runtime/bin/gen_snapshot.cc

 // Copyright (c) 2013, 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.
 
 // Generate a snapshot file after loading all the scripts specified on the
 // command line.
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ skipping 1248 matching lines @@
                                          commandline_packages_file);
     CHECK_RESULT(result);
 
     UriResolverIsolateScope::isolate = isolate;
     Dart_ExitScope();
     Dart_ExitIsolate();
 
     // Now we create an isolate into which we load all the code that needs to
     // be in the snapshot.
     isolate_data = new IsolateData(NULL, NULL, NULL);
-    if (Dart_CreateIsolate(NULL, NULL, NULL, NULL, isolate_data, &error) ==
-        NULL) {
+    intptr_t payload_bytes = 0;
+    const uint8_t* payload = NULL;

[siva, 2016/11/16 05:49:34]

Maybe names like kernel_length and kernel would be more consistent with other
places.

[Vyacheslav Egorov (Google), 2016/11/16 12:47:46]

Done.

+    const bool is_kernel_file =
+        TryReadKernel(app_script_name, &payload, &payload_bytes);
+    Dart_Isolate isolate =
+        is_kernel_file
+            ? Dart_CreateIsolateFromKernel(NULL, NULL, payload, payload_bytes,
+                                           NULL, isolate_data, &error)
+            : Dart_CreateIsolate(NULL, NULL, NULL, NULL, isolate_data, &error);
+    if (isolate == NULL) {
       fprintf(stderr, "%s", error);
       free(error);
       exit(255);
     }
     Dart_EnterScope();
     result = Dart_SetEnvironmentCallback(EnvironmentCallback);
     CHECK_RESULT(result);
 
     // Set up the library tag handler in such a manner that it will use the
     // URL mapping specified on the command line to load the libraries.
     result = Dart_SetLibraryTagHandler(CreateSnapshotLibraryTagHandler);
     CHECK_RESULT(result);
 
     Dart_QualifiedFunctionName* entry_points =
         ParseEntryPointsManifestIfPresent();
 
-    intptr_t payload_bytes = 0;
-    const uint8_t* payload = NULL;
-    const bool is_kernel_file =
-        TryReadKernel(app_script_name, &payload, &payload_bytes);
-
     if (is_kernel_file) {
       Dart_Handle library = Dart_LoadKernel(payload, payload_bytes);
       free(const_cast<uint8_t*>(payload));
       if (Dart_IsError(library)) FATAL("Failed to load app from Kernel IR");
     } else {
       // Set up the library tag handler in such a manner that it will use the
       // URL mapping specified on the command line to load the libraries.
       result = Dart_SetLibraryTagHandler(CreateSnapshotLibraryTagHandler);
       CHECK_RESULT(result);
     }
@@ skipping 34 matching lines @@
   EventHandler::Stop();
   return 0;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   return dart::bin::main(argc, argv);
 }