VM: [Kernel] Split kernel API into 3 steps: ([read binary], parse-binary, bootstrap, load program)

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 788 matching lines @@
   }
 
   // If the script is a Kernel binary, then we will try to bootstrap from the
   // script.
   const uint8_t* kernel_file = NULL;
   intptr_t kernel_length = -1;
   const bool is_kernel =
       !run_app_snapshot &&
       TryReadKernel(script_uri, &kernel_file, &kernel_length);
 
+  void* kernel_program = NULL;
+  if (is_kernel) {
+    kernel_program = Dart_ReadKernelBinary(kernel_file, kernel_length);
+    free(const_cast<uint8_t*>(kernel_file));
+  }
+
   IsolateData* isolate_data =
       new IsolateData(script_uri, package_root, packages_config);
   Dart_Isolate isolate =
-      is_kernel ? Dart_CreateIsolateFromKernel(script_uri, main, kernel_file,
-                                               kernel_length, flags,
-                                               isolate_data, error)
+      is_kernel ? Dart_CreateIsolateFromKernel(script_uri, main, kernel_program,
+                                               flags, isolate_data, error)
                 : Dart_CreateIsolate(script_uri, main, isolate_snapshot_buffer,
                                      flags, isolate_data, error);
-  if (is_kernel) {
-    free(const_cast<uint8_t*>(kernel_file));
-  }
-
   if (isolate == NULL) {
     delete isolate_data;
     return NULL;
   }
 
   Dart_EnterScope();
 
   // Set up the library tag handler for this isolate.
   Dart_Handle result = Dart_SetLibraryTagHandler(Loader::LibraryTagHandler);
   CHECK_RESULT(result);
 
   if (is_kernel) {
-    // TODO(27590): We should not read the kernel file again!
-    if (!TryReadKernel(script_uri, &kernel_file, &kernel_length)) {
-      FATAL("Failed to read kernel second time");
-    }
-    Dart_Handle result = Dart_LoadKernel(kernel_file, kernel_length);
-    free(const_cast<uint8_t*>(kernel_file));
+    Dart_Handle result = Dart_LoadKernel(kernel_program);
     CHECK_RESULT(result);
   }
   if (is_kernel || (isolate_snapshot_buffer != NULL)) {
     // Setup the native resolver as the snapshot does not carry it.
     Builtin::SetNativeResolver(Builtin::kBuiltinLibrary);
     Builtin::SetNativeResolver(Builtin::kIOLibrary);
   }
   if (run_app_snapshot) {
     Dart_Handle result = Loader::ReloadNativeExtensions();
     CHECK_RESULT(result);
@@ skipping 1104 matching lines @@
   Platform::Exit(Process::GlobalExitCode());
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   dart::bin::main(argc, argv);
   UNREACHABLE();
 }