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

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 1640 matching lines @@
     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(app_script_name, commandline_package_root,
                                    commandline_packages_file, NULL);
-    const uint8_t* kernel = NULL;
-    intptr_t kernel_length = 0;
-    const bool is_kernel_file =
-        dfe.TryReadKernelFile(app_script_name, &kernel, &kernel_length);
-
     if ((dependencies_filename != NULL) || print_dependencies) {
       isolate_data->set_dependencies(new MallocGrowableArray<char*>());
     }
 
-    void* kernel_program = NULL;
-    if (is_kernel_file) {
-      kernel_program = Dart_ReadKernelBinary(kernel, kernel_length);
-      free(const_cast<uint8_t*>(kernel));
+    Dart_Isolate isolate = NULL;
+    void* kernel_program = dfe.ReadScript(app_script_name);
+    if (kernel_program != NULL) {
+      isolate = Dart_CreateIsolateFromKernel(NULL, NULL, kernel_program, NULL,
+                                             isolate_data, &error);
+    } else {
+      isolate = Dart_CreateIsolate(NULL, NULL, isolate_snapshot_data,
+                                   isolate_snapshot_instructions, NULL,
+                                   isolate_data, &error);
     }
-
-    Dart_Isolate isolate =
-        is_kernel_file
-            ? Dart_CreateIsolateFromKernel(NULL, NULL, kernel_program, NULL,
-                                           isolate_data, &error)
-            : Dart_CreateIsolate(NULL, NULL, isolate_snapshot_data,
-                                 isolate_snapshot_instructions, NULL,
-                                 isolate_data, &error);
     if (isolate == NULL) {
       Log::PrintErr("%s\n", error);
       free(error);
       exit(kErrorExitCode);
     }
     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);
 
     if (commandline_packages_file != NULL) {
       AddDependency(commandline_packages_file);
     }
 
     Dart_QualifiedFunctionName* entry_points =
         ParseEntryPointsManifestIfPresent();
 
-    if (is_kernel_file) {
+    if (kernel_program != NULL) {
       Dart_Handle library = Dart_LoadKernel(kernel_program);
       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);
     }
 
     SetupStubNativeResolversForPrecompilation(entry_points);
 
     SetupStubNativeResolvers();
 
-    if (!is_kernel_file) {
+    if (kernel_program == NULL) {
       // Load the specified script.
       library = LoadSnapshotCreationScript(app_script_name);
       CHECK_RESULT(library);
 
       ImportNativeEntryPointLibrariesIntoRoot(entry_points);
     }
 
     // Ensure that we mark all libraries as loaded.
     result = Dart_FinalizeLoading(false);
     CHECK_RESULT(result);
@@ skipping 54 matching lines @@
   delete mapped_isolate_snapshot_data;
   return 0;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   return dart::bin::main(argc, argv);
 }