[VM/SDK] Switch kernel isolate to run in Dart 2 mode

- Switch the kernel isolate to run in Dart2 mode
- Refactor build rules so bootstrapping of the front end happens
  with a prebuilt dart sdk
- Refactor application snapshot build rules so the kernel application
  snapshot rule does not get into a cyclic dependency during the
  bootstrap stage

Change-Id: I067c5f1165fb93811dcc8e390a8bf381db721e5b
Reviewed-on: https://dart-review.googlesource.com/70461
Reviewed-by: Siva Annamalai <asiva@google.com>
Commit-Queue: Siva Annamalai <asiva@google.com>

BUILD.gn

@@ -51,12 +51,8 @@ group("runtime") {
     "runtime/bin:sample_extension",
     "runtime/bin:test_extension",
     "runtime/vm:kernel_platform_files($host_toolchain)",
-
-    # TODO(rmacnak): Link this into 'dart'.
-    "utils/kernel-service:copy_kernel_service_snapshot",
     "utils/kernel-service:kernel-service",
   ]
-
   if (target_supports_aot) {
     deps += [ "runtime/bin:precompiler_entry_points_json" ]
   }

pkg/vm/bin/kernel_service.dart

@@ -260,8 +260,8 @@ Future _processExpressionCompilationRequest(request) async {
   final SendPort port = request[1];
   final int isolateId = request[2];
   final String expression = request[3];
-  final List definitions = request[4];
-  final List typeDefinitions = request[5];
+  final List<String> definitions = request[4].cast<String>();
+  final List<String> typeDefinitions = request[5].cast<String>();
   final String libraryUri = request[6];
   final String klass = request[7]; // might be null
   final bool isStatic = request[8];

runtime/bin/BUILD.gn

@@ -1237,6 +1237,8 @@ executable("run_vm_tests") {
 
   sources = [
               "builtin_nolib.cc",
+              "dfe.cc",
+              "dfe.h",
               "error_exit.cc",
               "error_exit.h",
               "run_vm_tests.cc",

runtime/bin/main.cc

@@ -459,10 +459,7 @@ static Dart_Isolate CreateAndSetupKernelIsolate(const char* script_uri,
                                                 Dart_IsolateFlags* flags,
                                                 char** error,
                                                 int* exit_code) {
-  const char* kernel_snapshot_uri = NULL;
-  if (Options::gen_snapshot_kind() != kAppJIT) {
-    kernel_snapshot_uri = dfe.frontend_filename();
-  }
+  const char* kernel_snapshot_uri = dfe.frontend_filename();
   const char* uri =
       kernel_snapshot_uri != NULL ? kernel_snapshot_uri : script_uri;
 
@@ -473,20 +470,19 @@ static Dart_Isolate CreateAndSetupKernelIsolate(const char* script_uri,
   Dart_Isolate isolate;
   IsolateData* isolate_data = NULL;
   bool isolate_run_app_snapshot = false;
-  if (kernel_snapshot_uri != NULL) {
-    // Kernel isolate uses an app snapshot or the core libraries snapshot.
-    const uint8_t* isolate_snapshot_data = core_isolate_snapshot_data;
-    const uint8_t* isolate_snapshot_instructions =
-        core_isolate_snapshot_instructions;
-    AppSnapshot* app_snapshot = Snapshot::TryReadAppSnapshot(uri);
-    if (app_snapshot != NULL) {
-      isolate_run_app_snapshot = true;
-      const uint8_t* ignore_vm_snapshot_data;
-      const uint8_t* ignore_vm_snapshot_instructions;
-      app_snapshot->SetBuffers(
-          &ignore_vm_snapshot_data, &ignore_vm_snapshot_instructions,
-          &isolate_snapshot_data, &isolate_snapshot_instructions);
-    }
+  AppSnapshot* app_snapshot = NULL;
+  // Kernel isolate uses an app snapshot or uses the dill file.
+  if ((kernel_snapshot_uri != NULL) &&
+      (app_snapshot = Snapshot::TryReadAppSnapshot(kernel_snapshot_uri)) !=
+          NULL) {
+    const uint8_t* isolate_snapshot_data = NULL;
+    const uint8_t* isolate_snapshot_instructions = NULL;
+    const uint8_t* ignore_vm_snapshot_data;
+    const uint8_t* ignore_vm_snapshot_instructions;
+    isolate_run_app_snapshot = true;
+    app_snapshot->SetBuffers(
+        &ignore_vm_snapshot_data, &ignore_vm_snapshot_instructions,
+        &isolate_snapshot_data, &isolate_snapshot_instructions);
     IsolateData* isolate_data =
         new IsolateData(uri, package_root, packages_config, app_snapshot);
     isolate = Dart_CreateIsolate(
@@ -1258,7 +1254,13 @@ void main(int argc, char** argv) {
                                       application_kernel_buffer_size);
     // Since we saw a dill file, it means we have to turn on all the
     // preview_dart_2 options.
-    Options::SetDart2Options(&vm_options);
+    if (Options::no_preview_dart_2()) {
+      Log::PrintErr(
+          "A kernel file is specified as the input, "
+          "--no-preview-dart-2 option is incompatible with it\n");
+      Platform::Exit(kErrorExitCode);
+    }
+    Options::dfe()->set_use_dfe();
   }
 #endif
 

runtime/bin/run_vm_tests.cc

@@ -125,43 +125,45 @@ static Dart_Isolate CreateIsolateAndSetup(const char* script_uri,
         strdup("Spawning of only Kernel isolate is supported in run_vm_tests.");
     return NULL;
   }
-  if (kernel_snapshot == NULL) {
-    *error =
-        strdup("Kernel snapshot location has to be specified via --dfe option");
-    return NULL;
-  }
-  script_uri = kernel_snapshot;
+  Dart_Isolate isolate = NULL;
+  bin::IsolateData* isolate_data = NULL;
+  const uint8_t* kernel_service_buffer = NULL;
+  intptr_t kernel_service_buffer_size = 0;
 
-  // Kernel isolate uses an app snapshot or the core libraries snapshot.
-  bool isolate_run_script_snapshot = false;
-  const uint8_t* isolate_snapshot_data = bin::core_isolate_snapshot_data;
-  const uint8_t* isolate_snapshot_instructions =
-      bin::core_isolate_snapshot_instructions;
-  bin::AppSnapshot* app_snapshot = NULL;
-  switch (bin::DartUtils::SniffForMagicNumber(script_uri)) {
-    case bin::DartUtils::kAppJITMagicNumber: {
-      app_snapshot = bin::Snapshot::TryReadAppSnapshot(script_uri);
-      ASSERT(app_snapshot != NULL);
-
-      const uint8_t* ignore_vm_snapshot_data;
-      const uint8_t* ignore_vm_snapshot_instructions;
-      app_snapshot->SetBuffers(
-          &ignore_vm_snapshot_data, &ignore_vm_snapshot_instructions,
-          &isolate_snapshot_data, &isolate_snapshot_instructions);
-      break;
-    }
-    case bin::DartUtils::kSnapshotMagicNumber: {
-      isolate_run_script_snapshot = true;
-      break;
-    }
-    default:
-      return NULL;
+  // Kernel isolate uses an app snapshot or the kernel service dill file.
+  if (kernel_snapshot != NULL &&
+      (bin::DartUtils::SniffForMagicNumber(kernel_snapshot) ==
+       bin::DartUtils::kAppJITMagicNumber)) {
+    script_uri = kernel_snapshot;
+    bin::AppSnapshot* app_snapshot =
+        bin::Snapshot::TryReadAppSnapshot(script_uri);
+    ASSERT(app_snapshot != NULL);
+    const uint8_t* ignore_vm_snapshot_data;
+    const uint8_t* ignore_vm_snapshot_instructions;
+    const uint8_t* isolate_snapshot_data;
+    const uint8_t* isolate_snapshot_instructions;
+    app_snapshot->SetBuffers(
+        &ignore_vm_snapshot_data, &ignore_vm_snapshot_instructions,
+        &isolate_snapshot_data, &isolate_snapshot_instructions);
+    isolate_data = new bin::IsolateData(script_uri, package_root,
+                                        packages_config, app_snapshot);
+    isolate = Dart_CreateIsolate(
+        DART_KERNEL_ISOLATE_NAME, main, isolate_snapshot_data,
+        isolate_snapshot_instructions, NULL, NULL, flags, isolate_data, error);
+  } else {
+    bin::dfe.Init();
+    bin::dfe.LoadKernelService(&kernel_service_buffer,
+                               &kernel_service_buffer_size);
+    ASSERT(kernel_service_buffer != NULL);
+    isolate_data =
+        new bin::IsolateData(script_uri, package_root, packages_config, NULL);
+    isolate_data->set_kernel_buffer(const_cast<uint8_t*>(kernel_service_buffer),
+                                    kernel_service_buffer_size,
+                                    false /* take_ownership */);
+    isolate = Dart_CreateIsolateFromKernel(
+        script_uri, main, kernel_service_buffer, kernel_service_buffer_size,
+        flags, isolate_data, error);
   }
-  bin::IsolateData* isolate_data = new bin::IsolateData(
-      script_uri, package_root, packages_config, app_snapshot);
-  Dart_Isolate isolate = Dart_CreateIsolate(
-      DART_KERNEL_ISOLATE_NAME, main, isolate_snapshot_data,
-      isolate_snapshot_instructions, NULL, NULL, flags, isolate_data, error);
   if (isolate == NULL) {
     delete isolate_data;
     return NULL;
@@ -169,22 +171,18 @@ static Dart_Isolate CreateIsolateAndSetup(const char* script_uri,
 
   Dart_EnterScope();
 
-  if (isolate_run_script_snapshot) {
-    uint8_t* payload;
-    intptr_t payload_length;
-    void* file = bin::DartUtils::OpenFile(script_uri, false);
-    bin::DartUtils::ReadFile(&payload, &payload_length, file);
-    bin::DartUtils::CloseFile(file);
-
-    Dart_Handle result = Dart_LoadScriptFromSnapshot(payload, payload_length);
-    CHECK_RESULT(result);
-  }
-
   bin::DartUtils::SetOriginalWorkingDirectory();
   Dart_Handle result = bin::DartUtils::PrepareForScriptLoading(
       false /* is_service_isolate */, false /* trace_loading */);
   CHECK_RESULT(result);
 
+  // Setup kernel service as the main script for this isolate.
+  if (kernel_service_buffer) {
+    result = Dart_LoadScriptFromKernel(kernel_service_buffer,
+                                       kernel_service_buffer_size);
+    CHECK_RESULT(result);
+  }
+
   Dart_ExitScope();
   Dart_ExitIsolate();
   *error = Dart_IsolateMakeRunnable(isolate);
@@ -217,6 +215,9 @@ static int Main(int argc, const char** argv) {
   // Save the console state so we can restore it later.
   dart::bin::Console::SaveConfig();
 
+  // Store the executable name.
+  dart::bin::Platform::SetExecutableName(argv[0]);
+
   if (argc < 2) {
     // Bad parameter count.
     PrintUsage();

runtime/bin/snapshot_utils.cc

@@ -337,12 +337,19 @@ void Snapshot::GenerateKernel(const char* snapshot_filename,
                               bool strong,
                               const char* package_config) {
 #if !defined(EXCLUDE_CFE_AND_KERNEL_PLATFORM) && !defined(TESTING)
-  Dart_KernelCompilationResult result =
-      dfe.CompileScript(script_name, strong, false, package_config);
-  if (result.status != Dart_KernelCompilationStatus_Ok) {
-    ErrorExit(kErrorExitCode, "%s\n", result.error);
+  uint8_t* kernel_buffer = NULL;
+  intptr_t kernel_buffer_size = 0;
+  dfe.ReadScript(script_name, &kernel_buffer, &kernel_buffer_size);
+  if (kernel_buffer != NULL) {
+    WriteSnapshotFile(snapshot_filename, kernel_buffer, kernel_buffer_size);
+  } else {
+    Dart_KernelCompilationResult result =
+        dfe.CompileScript(script_name, strong, false, package_config);
+    if (result.status != Dart_KernelCompilationStatus_Ok) {
+      ErrorExit(kErrorExitCode, "%s\n", result.error);
+    }
+    WriteSnapshotFile(snapshot_filename, result.kernel, result.kernel_size);
   }
-  WriteSnapshotFile(snapshot_filename, result.kernel, result.kernel_size);
 #else
   UNREACHABLE();
 #endif  // !defined(EXCLUDE_CFE_AND_KERNEL_PLATFORM) && !defined(TESTING)

runtime/runtime_args.gni

@@ -86,3 +86,14 @@ declare_args() {
   # product).
   exclude_kernel_service = false
 }
+
+declare_args() {
+  # We create a kernel service app-jit snapshot only for when the target
+  # architecture is x64 for other cases we will use the '.dill' file
+  # which is already linked in the VM.
+  if (dart_target_arch == "x64") {
+    create_kernel_service_snapshot = true
+  } else {
+    create_kernel_service_snapshot = false
+  }
+}

runtime/vm/isolate.cc

@@ -643,7 +643,7 @@ MessageHandler::MessageStatus IsolateMessageHandler::HandleMessage(
 
 #ifndef PRODUCT
 void IsolateMessageHandler::NotifyPauseOnStart() {
-  if (!FLAG_support_service) {
+  if (!FLAG_support_service || Isolate::IsVMInternalIsolate(I)) {
     return;
   }
   if (Service::debug_stream.enabled() || FLAG_warn_on_pause_with_no_debugger) {
@@ -659,7 +659,7 @@ void IsolateMessageHandler::NotifyPauseOnStart() {
 }
 
 void IsolateMessageHandler::NotifyPauseOnExit() {
-  if (!FLAG_support_service) {
+  if (!FLAG_support_service || Isolate::IsVMInternalIsolate(I)) {
     return;
   }
   if (Service::debug_stream.enabled() || FLAG_warn_on_pause_with_no_debugger) {
@@ -1310,7 +1310,8 @@ const char* Isolate::MakeRunnable() {
       event->Complete();
     }
   }
-  if (FLAG_support_service && Service::isolate_stream.enabled()) {
+  if (FLAG_support_service && !Isolate::IsVMInternalIsolate(this) &&
+      Service::isolate_stream.enabled()) {
     ServiceEvent runnableEvent(this, ServiceEvent::kIsolateRunnable);
     Service::HandleEvent(&runnableEvent);
   }
@@ -2438,10 +2439,7 @@ void Isolate::AppendServiceExtensionCall(const Instance& closure,
 // done atomically.
 void Isolate::RegisterServiceExtensionHandler(const String& name,
                                               const Instance& closure) {
-  if (!FLAG_support_service) {
-    return;
-  }
-  if (Isolate::IsVMInternalIsolate(this)) {
+  if (!FLAG_support_service || Isolate::IsVMInternalIsolate(this)) {
     return;
   }
   GrowableObjectArray& handlers =

runtime/vm/isolate_reload.cc

@@ -469,6 +469,9 @@ IsolateReloadContext::~IsolateReloadContext() {
 }
 
 void IsolateReloadContext::ReportError(const Error& error) {
+  if (!FLAG_support_service || Isolate::IsVMInternalIsolate(I)) {
+    return;
+  }
   if (FLAG_trace_reload) {
     THR_Print("ISO-RELOAD: Error: %s\n", error.ToErrorCString());
   }
@@ -478,6 +481,9 @@ void IsolateReloadContext::ReportError(const Error& error) {
 }
 
 void IsolateReloadContext::ReportSuccess() {
+  if (!FLAG_support_service || Isolate::IsVMInternalIsolate(I)) {
+    return;
+  }
   ServiceEvent service_event(I, ServiceEvent::kIsolateReload);
   Service::HandleEvent(&service_event);
 }

runtime/vm/kernel_isolate.cc

@@ -92,9 +92,10 @@ class RunKernelTask : public ThreadPool::Task {
     api_flags.enable_asserts = false;
     api_flags.enable_error_on_bad_type = false;
     api_flags.enable_error_on_bad_override = false;
-    api_flags.reify_generic_functions = false;
-    api_flags.strong = false;
-    api_flags.sync_async = false;
+    api_flags.use_dart_frontend = true;
+    api_flags.reify_generic_functions = true;
+    api_flags.strong = true;
+    api_flags.sync_async = true;
 #if !defined(DART_PRECOMPILER) && !defined(TARGET_ARCH_DBC) &&                 \
     !defined(DART_USE_INTERPRETER)
     api_flags.use_field_guards = true;
@@ -233,12 +234,10 @@ void KernelIsolate::Run() {
 }
 
 void KernelIsolate::Shutdown() {
-  Isolate::KillIfExists(isolate_, Isolate::kInternalKillMsg);
-  {
-    MonitorLocker ml(monitor_);
-    while (isolate_ != NULL) {
-      ml.Wait();
-    }
+  MonitorLocker ml(monitor_);
+  while (isolate_ != NULL) {
+    Isolate::KillIfExists(isolate_, Isolate::kInternalKillMsg);
+    ml.Wait();
   }
 }
 

sdk/BUILD.gn

@@ -14,6 +14,7 @@
 # fail.
 
 import("../build/dart/copy_tree.gni")
+import("../runtime/runtime_args.gni")
 
 declare_args() {
   # Build a SDK with less stuff. It excludes dart2js, ddc, and web libraries.
@@ -129,15 +130,19 @@ _platform_sdk_snapshots = [
     "dartfmt",
     "../utils/dartfmt",
   ],
-  [
-    "kernel-service",
-    "../utils/kernel-service",
-  ],
   [
     "pub",
     "../utils/pub",
   ],
 ]
+if (create_kernel_service_snapshot) {
+  _platform_sdk_snapshots += [
+    [
+      "kernel-service",
+      "../utils/kernel-service:kernel-service_snapshot",
+    ],
+  ]
+}
 
 _full_sdk_snapshots = [
   [
@@ -172,15 +177,19 @@ _full_sdk_snapshots = [
     "kernel_worker",
     "../utils/bazel:kernel_worker",
   ],
-  [
-    "kernel-service",
-    "../utils/kernel-service",
-  ],
   [
     "pub",
     "../utils/pub",
   ],
 ]
+if (create_kernel_service_snapshot) {
+  _full_sdk_snapshots += [
+    [
+      "kernel-service",
+      "../utils/kernel-service:kernel-service_snapshot",
+    ],
+  ]
+}
 
 # Libraries that go under lib/
 _full_sdk_libraries = [

tools/testing/dart/compiler_configuration.dart

@@ -833,14 +833,8 @@ class AppJitCompilerConfiguration extends CompilerConfiguration {
 
   int get timeoutMultiplier {
     var multiplier = 1;
-    if (_isDebug) multiplier *= 4;
+    if (_isDebug) multiplier *= 2;
     if (_isChecked) multiplier *= 2;
-
-    // The CL in 396c92e disabled running the kernel-isolate from app-jit
-    // snapshots if the VM is run with --snapshot-kind=app-jit. This made our
-    // app-jit tests run slower.
-    if (previewDart2) multiplier *= 2;
-
     return multiplier;
   }
 

utils/analysis_server/BUILD.gn

@@ -5,7 +5,6 @@
 import("../application_snapshot.gni")
 
 application_snapshot("analysis_server") {
-  dart_version = 2
   main_dart = "../../pkg/analysis_server/bin/server.dart"
   training_args = [
     "--train-using=" + rebase_path("../../pkg/analyzer_cli"),

utils/application_snapshot.gni

@@ -3,15 +3,17 @@
 # BSD-style license that can be found in the LICENSE file.
 
 import("../build/dart/dart_action.gni")
+import("../runtime/runtime_args.gni")
 
 _dart_root = get_path_info("..", "abspath")
 
 declare_args() {
   # Default to building app-jit snapshots. The simulator and cross builds
   # override this to script snapshots to cut down on build time.
-  dart_snapshot_kind = "app-jit"
   if (target_cpu != host_cpu) {
     dart_snapshot_kind = "script"
+  } else {
+    dart_snapshot_kind = "app-jit"
   }
 }
 
@@ -24,12 +26,8 @@ declare_args() {
 #  training_args (required):
 #    Arguments to pass to the Dart application for the training run.
 #
-#  dart_version (optional):
-#    Must be 1 or 2. Defaults to 1.
-#
 #  vm_args (optional):
-#    Additional arguments to the Dart VM. Do not put --preview-dart-2 here.
-#    Instead set dart_version = 2.
+#    Additional arguments to the Dart VM.
 #
 #  name (optional):
 #    The name of the snapshot if different from the target name. The output
@@ -46,7 +44,7 @@ declare_args() {
 #
 #  output (optional):
 #    Overrides the full output path.
-template("application_snapshot") {
+template("_application_snapshot") {
   assert(defined(invoker.main_dart), "Must specify 'main_dart'")
   assert(defined(invoker.training_args), "Must specify 'training_args'")
   snapshot_vm_args = []
@@ -76,27 +74,8 @@ template("application_snapshot") {
   if (defined(invoker.output)) {
     output = invoker.output
   }
-  # TODO(asiva), flip default once the VM is dart2 by default.
-  dart_version = 1
-  if (defined(invoker.dart_version)) {
-    dart_version = invoker.dart_version
-  }
-  assert(dart_version == 1 || dart_version == 2,
-      "For $target_name, dart_version must be 1 or 2")
   dart_action(target_name) {
     deps = extra_deps
-
-    if (dart_version == 1) {
-      snapshot_vm_args += [ "--no-preview-dart-2" ]
-    } else {
-      # HACK: When creating app-jit snapshots for Dart 2 apps, the standalone
-      # Dart VM binary requires the app-jit snapshot for the kernel service to
-      # be adjacent to it. This deps ensures that it is there, but a different
-      # approach will be needed when the kernel service itself switches to
-      # Dart 2 to avoid creating a circular dependence.
-      deps += [ "$_dart_root/utils/kernel-service:copy_kernel_service_snapshot"]
-    }
-
     depfile = "$output.d"
 
     script = main_dart
@@ -132,6 +111,107 @@ template("application_snapshot") {
   }
 }
 
+# Creates an app-jit snapshot for a Dart2 program based on a training run.
+#
+# Parameters:
+#  main_dart (required):
+#    The entrypoint to the Dart application.
+#
+#  training_args (required):
+#    Arguments to pass to the Dart application for the training run.
+#
+#  vm_args (optional):
+#    Additional arguments to the Dart VM. Do not put --no-preview-dart-2 here.
+#    Instead use the template application_snapshot_dart1.
+#
+#  name (optional):
+#    The name of the snapshot if different from the target name. The output
+#    will be in $root_gen_dir/$name.dart.snapshot.
+#
+#  deps (optional):
+#    Any build dependencies.
+#
+#  dot_packages (optional):
+#    The .packages file for the app. Defaults to the $_dart_root/.packages.
+#
+#  output (optional):
+#    Overrides the full output path.
+template("application_snapshot") {
+  _application_snapshot(target_name) {
+    forward_variables_from(invoker, "*")
+    if (!defined(invoker.deps)) {
+      deps = []
+    }
+    deps += [
+      "$_dart_root/utils/kernel-service:kernel-service_snapshot"
+    ]
+  }
+}
+
+# Creates an app-jit snapshot for a Dart1 program based on a training run.
+#
+# Parameters:
+#  main_dart (required):
+#    The entrypoint to the Dart application.
+#
+#  training_args (required):
+#    Arguments to pass to the Dart application for the training run.
+#
+#  vm_args (optional):
+#    Additional arguments to the Dart VM. Do not put --no-preview-dart-2 here.
+#
+#  name (optional):
+#    The name of the snapshot if different from the target name. The output
+#    will be in $root_gen_dir/$name.dart.snapshot.
+#
+#  deps (optional):
+#    Any build dependencies.
+#
+#  dot_packages (optional):
+#    The .packages file for the app. Defaults to the $_dart_root/.packages.
+#
+#  output (optional):
+#    Overrides the full output path.
+template("application_snapshot_dart1") {
+  _application_snapshot(target_name) {
+    forward_variables_from(invoker, "*")
+    if (!defined(invoker.vm_args)) {
+      vm_args = []
+    }
+    vm_args += [ "--no-preview-dart-2" ]
+  }
+}
+
+# Creates an app-jit snapshot for the common FE based on a training run.
+#
+# Parameters:
+#  main_dart (required):
+#    The entrypoint to the Dart application.
+#
+#  training_args (required):
+#    Arguments to pass to the Dart application for the training run.
+#
+#  vm_args (optional):
+#    Additional arguments to the Dart VM. Do not put --no-preview-dart-2 here.
+#
+#  name (optional):
+#    The name of the snapshot if different from the target name. The output
+#    will be in $root_gen_dir/$name.dart.snapshot.
+#
+#  deps (optional):
+#    Any build dependencies.
+#
+#  dot_packages (optional):
+#    The .packages file for the app. Defaults to the $_dart_root/.packages.
+#
+#  output (optional):
+#    Overrides the full output path.
+template("kernel_application_snapshot") {
+  _application_snapshot(target_name) {
+    forward_variables_from(invoker, "*")
+  }
+}
+
 template("aot_assembly") {
   assert(defined(invoker.main_dart), "Must specify 'main_dart'")
   aot_vm_args = []

utils/bazel/BUILD.gn

@@ -7,5 +7,4 @@ import("../application_snapshot.gni")
 application_snapshot("kernel_worker") {
   main_dart = "kernel_worker.dart"
   training_args = [ "--help" ]
-  dart_version = 2
 }

utils/compiler/BUILD.gn

@@ -32,7 +32,7 @@ dart_action("dart2js_create_snapshot_entry") {
   # dart_action() needs kernel service snapshot to run in Dart 2 mode.
   # This can't be added as a dependency to dart_action() itself as it will
   # create a circular dependency.
-  deps += [ "../../utils/kernel-service:copy_kernel_service_snapshot" ]
+  deps += [ "../../utils/kernel-service:kernel-service" ]
 
   output_dir = rebase_path(target_gen_dir)
 
@@ -58,8 +58,6 @@ dart_action("dart2js_create_snapshot_entry") {
 }
 
 application_snapshot("dart2js") {
-  dart_version = 2
-
   deps = [
     ":compile_dart2js_platform",
     ":compile_dart2js_platform_strong",

utils/dartanalyzer/BUILD.gn

@@ -21,7 +21,6 @@ analyzer_files = exec_script("../../tools/list_dart_files.py",
                              "list lines")
 
 application_snapshot("generate_dartanalyzer_snapshot") {
-  dart_version = 2
   main_dart = "../../pkg/analyzer_cli/bin/analyzer.dart"
   training_args = [
     "--dart-sdk=" + rebase_path("../../sdk"),

utils/dartdevc/BUILD.gn

@@ -11,8 +11,6 @@ sdk_summary = "$target_gen_dir/ddc_sdk.sum"
 sdk_dill = "$target_gen_dir/kernel/ddc_sdk.dill"
 
 application_snapshot("dartdevc") {
-  dart_version = 2
-
   main_dart = "../../pkg/dev_compiler/bin/dartdevc.dart"
 
   training_args = [
@@ -35,8 +33,6 @@ application_snapshot("dartdevc") {
 }
 
 application_snapshot("dartdevk") {
-  dart_version = 2
-
   main_dart = "../../pkg/dev_compiler/bin/dartdevk.dart"
 
   training_args = [
@@ -93,7 +89,7 @@ template("dart2js_compile") {
     # dart_action() needs kernel service snapshot to run in Dart 2 mode.
     # This can't be added as a dependency to dart_action() itself as it will
     # create a circular dependency.
-    deps += [ "../../utils/kernel-service:copy_kernel_service_snapshot" ]
+    deps += [ "../../utils/kernel-service:kernel-service" ]
 
     inputs = sdk_lib_files + compiler_files + dev_compiler_files + [
                "$root_out_dir/dart2js_platform.dill",

utils/dartdoc/BUILD.gn

@@ -5,7 +5,6 @@
 import("../application_snapshot.gni")
 
 application_snapshot("dartdoc") {
-  dart_version = 2
   main_dart = "../../third_party/pkg/dartdoc/bin/dartdoc.dart"
   training_args = [ "--help" ]
 }

utils/dartfmt/BUILD.gn

@@ -5,7 +5,6 @@
 import("../application_snapshot.gni")
 
 application_snapshot("dartfmt") {
-  dart_version = 2
   main_dart = "../../third_party/pkg_tested/dart_style/bin/format.dart"
 
   # Train it on formatting its own source.

utils/kernel-service/BUILD.gn

@@ -4,24 +4,39 @@
 
 import("../../build/dart/dart_action.gni")
 import("../../build/dart/dart_host_sdk_toolchain.gni")
+import("../../runtime/runtime_args.gni")
 import("../application_snapshot.gni")
 
+group("kernel-service") {
+  if (create_kernel_service_snapshot) {
+    deps = [
+      # TODO(rmacnak): Link this into 'dart'.
+      ":copy_kernel-service_snapshot",
+    ]
+  } else {
+    deps = [
+      ":kernel_service_dill",
+    ]
+  }
+}
+
 # TODO: Switch this to use kernel based app-jit snapshot
 # when we are ready to switch to the kernel based core snapshots.
-application_snapshot("kernel-service") {
-  main_dart = "../../pkg/vm/bin/kernel_service.dart"
+kernel_application_snapshot("kernel-service_snapshot") {
+  main_dart = "$root_gen_dir/kernel_service.dill"
   deps = [
-    "../../runtime/vm:kernel_platform_files($dart_host_toolchain)",
+    ":kernel_service_dill",
   ]
   training_args = [
     "--train",
     "file://" + rebase_path("../../pkg/compiler/lib/src/dart2js.dart"),
   ]
+  output = "$root_gen_dir/kernel-service.dart.snapshot"
 }
 
-copy("copy_kernel_service_snapshot") {
+copy("copy_kernel-service_snapshot") {
   deps = [
-    ":kernel-service",
+    ":kernel-service_snapshot",
   ]
   sources = [
     "$root_gen_dir/kernel-service.dart.snapshot",
@@ -40,14 +55,15 @@ application_snapshot("frontend_server") {
   training_args = [
     "--train",
     "--sdk-root=$sdk_root/",
-    "--platform=$sdk_root/vm_platform.dill",
+    "--platform=$sdk_root/vm_platform_strong.dill",
   ]
   output = "$root_out_dir/frontend_server.dart.snapshot"
 }
 
 prebuilt_dart_action("kernel_service_dill") {
   deps = [
-    "../../runtime/vm:vm_legacy_platform",
+    "../../runtime/vm:vm_platform",
+    "../../runtime/vm:kernel_platform_files($dart_host_toolchain)",
   ]
   kernel_service_script = "../../pkg/vm/bin/kernel_service.dart"
   gen_kernel_script = "../../pkg/vm/bin/gen_kernel.dart"
@@ -55,7 +71,7 @@ prebuilt_dart_action("kernel_service_dill") {
   inputs = [
     gen_kernel_script,
     kernel_service_script,
-    "$root_out_dir/vm_platform.dill",
+    "$root_out_dir/vm_platform_strong.dill",
   ]
   output = "$root_gen_dir/kernel_service.dill"
   outputs = [
@@ -74,14 +90,10 @@ prebuilt_dart_action("kernel_service_dill") {
 
   script = gen_kernel_script
 
-  # TODO: Switch over to vm_platform_strong.dill and remove the
-  # flags --no-strong-mode once https://github.com/dart-lang/sdk/issues/31623
-  # is fixed.
   args = [
     "--packages=" + rebase_path("../../.packages"),
-    "--platform=" + rebase_path("$root_out_dir/vm_platform.dill"),
+    "--platform=" + rebase_path("$root_out_dir/vm_platform_strong.dill"),
     "--no-aot",
-    "--no-strong-mode",
     "--no-embed-sources",
     "--output=" + rebase_path("$root_gen_dir/kernel_service.dill"),
     rebase_path(kernel_service_script),

utils/pub/BUILD.gn

@@ -5,7 +5,6 @@
 import("../application_snapshot.gni")
 
 application_snapshot("pub") {
-  dart_version = 2
   main_dart = "../../third_party/pkg/pub/bin/pub.dart"
   training_args = [ "--help" ]
 }