Eliminate support for Dart 1 (flutter#5504)

Eliminates support for running directly from sources or script snapshots. In
debug mode, we run from a kernel snapshot; in profile and release modes, we
link in AOT-compiled code.

Renames --dart-non-checked-mode to --disable-dart-asserts since checked mode
does not make sense in Dart 2.

common/settings.cc

@@ -11,7 +11,6 @@ namespace blink {
 std::string Settings::ToString() const {
   std::stringstream stream;
   stream << "Settings: " << std::endl;
-  stream << "script_snapshot_path: " << script_snapshot_path << std::endl;
   stream << "vm_snapshot_data_path: " << vm_snapshot_data_path << std::endl;
   stream << "vm_snapshot_instr_path: " << vm_snapshot_instr_path << std::endl;
   stream << "isolate_snapshot_data_path: " << isolate_snapshot_data_path
@@ -32,7 +31,6 @@ std::string Settings::ToString() const {
   stream << "trace_startup: " << trace_startup << std::endl;
   stream << "endless_trace_buffer: " << endless_trace_buffer << std::endl;
   stream << "enable_dart_profiling: " << enable_dart_profiling << std::endl;
-  stream << "dart_non_checked_mode: " << dart_non_checked_mode << std::endl;
   stream << "enable_observatory: " << enable_observatory << std::endl;
   stream << "observatory_port: " << observatory_port << std::endl;
   stream << "ipv6: " << ipv6 << std::endl;

common/settings.h

@@ -23,7 +23,6 @@ using TaskObserverRemove = std::function<void(intptr_t /* key */)>;
 
 struct Settings {
   // VM settings
-  std::string script_snapshot_path;
   std::string platform_kernel_path;
 
   std::string vm_snapshot_data_path;
@@ -47,7 +46,6 @@ struct Settings {
   bool trace_startup = false;
   bool endless_trace_buffer = false;
   bool enable_dart_profiling = false;
-  bool dart_non_checked_mode = false;
   // Used as the script URI in debug messages. Does not affect how the Dart code
   // is executed.
   std::string advisory_script_uri = "main.dart";

runtime/dart_isolate.cc

@@ -277,18 +277,9 @@ bool DartIsolate::PrepareForRunningFromPrecompiledCode() {
   return true;
 }
 
-static bool LoadScriptSnapshot(std::shared_ptr<const fml::Mapping> mapping,
-                               bool last_piece) {
-  FXL_CHECK(last_piece) << "Script snapshots cannot be divided";
-  if (tonic::LogIfError(Dart_LoadScriptFromSnapshot(mapping->GetMapping(),
-                                                    mapping->GetSize()))) {
-    return false;
-  }
-  return true;
-}
-
 static bool LoadKernelSnapshot(std::shared_ptr<const fml::Mapping> mapping,
                                bool last_piece) {
+  FXL_DCHECK(Dart_IsKernel(mapping->GetMapping(), mapping->GetSize())) << "Only kernel snapshots are supported";
   Dart_Handle library =
       Dart_LoadLibraryFromKernel(mapping->GetMapping(), mapping->GetSize());
   if (tonic::LogIfError(library)) {
@@ -307,16 +298,6 @@ static bool LoadKernelSnapshot(std::shared_ptr<const fml::Mapping> mapping,
   return true;
 }
 
-static bool LoadSnapshot(std::shared_ptr<const fml::Mapping> mapping,
-                         bool last_piece) {
-  if (Dart_IsKernel(mapping->GetMapping(), mapping->GetSize())) {
-    return LoadKernelSnapshot(std::move(mapping), last_piece);
-  } else {
-    return LoadScriptSnapshot(std::move(mapping), last_piece);
-  }
-  return false;
-}
-
 FXL_WARN_UNUSED_RESULT
 bool DartIsolate::PrepareForRunningFromSnapshot(
     std::shared_ptr<const fml::Mapping> mapping,
@@ -340,7 +321,7 @@ bool DartIsolate::PrepareForRunningFromSnapshot(
     return false;
   }
 
-  if (!LoadSnapshot(mapping, last_piece)) {
+  if (!LoadKernelSnapshot(mapping, last_piece)) {
     return false;
   }
 
@@ -566,20 +547,12 @@ Dart_Isolate DartIsolate::DartCreateAndStartServiceIsolate(
   // thread.
   service_isolate->ResetWeakPtrFactory();
 
-  const bool isolate_snapshot_is_dart_2 = Dart_IsDart2Snapshot(
-      vm->GetIsolateSnapshot()->GetData()->GetSnapshotPointer());
-  const bool is_preview_dart2 =
-      (vm->GetPlatformKernel().GetSize() > 0) || isolate_snapshot_is_dart_2;
-  const bool running_from_sources =
-      !DartVM::IsRunningPrecompiledCode() && !is_preview_dart2;
-
   tonic::DartState::Scope scope(service_isolate);
   if (!DartServiceIsolate::Startup(
           settings.ipv6 ? "::1" : "127.0.0.1",  // server IP address
           settings.observatory_port,            // server observatory port
           tonic::DartState::HandleLibraryTag,   // embedder library tag handler
-          running_from_sources,                 // running from source code
-          false,  //  disable websocket origin check
+          false,  // disable websocket origin check
           error   // error (out)
           )) {
     // Error is populated by call to startup.

runtime/dart_service_isolate.cc

@@ -27,7 +27,6 @@
   }
 
 #define kLibrarySourceNamePrefix "/vmservice"
-static const char* kServiceIsolateScript = "vmservice_io.dart";
 
 namespace flutter {
 namespace runtime {
@@ -84,7 +83,6 @@ void DartServiceIsolate::Shutdown(Dart_NativeArguments args) {
 bool DartServiceIsolate::Startup(std::string server_ip,
                                  intptr_t server_port,
                                  Dart_LibraryTagHandler embedder_tag_handler,
-                                 bool running_from_sources,
                                  bool disable_origin_check,
                                  char** error) {
   Dart_Isolate isolate = Dart_CurrentIsolate();
@@ -108,31 +106,14 @@ bool DartServiceIsolate::Startup(std::string server_ip,
         &flutter::runtime::__flutter_embedded_service_isolate_resources_[0]);
   }
 
-  Dart_Handle result;
-
-  if (running_from_sources) {
-    // Use our own library tag handler when loading service isolate sources.
-    Dart_SetLibraryTagHandler(DartServiceIsolate::LibraryTagHandler);
-    // Load main script.
-    Dart_Handle library = LoadScript(kServiceIsolateScript);
-    FXL_DCHECK(library != Dart_Null());
-    SHUTDOWN_ON_ERROR(library);
-    // Setup native entry resolution.
-    result = Dart_SetNativeResolver(library, GetNativeFunction, GetSymbol);
-
-    SHUTDOWN_ON_ERROR(result);
-    // Finalize loading.
-    result = Dart_FinalizeLoading(false);
-    SHUTDOWN_ON_ERROR(result);
-  } else {
-    Dart_Handle uri = Dart_NewStringFromCString("dart:vmservice_io");
-    Dart_Handle library = Dart_LookupLibrary(uri);
-    SHUTDOWN_ON_ERROR(library);
-    result = Dart_SetRootLibrary(library);
-    SHUTDOWN_ON_ERROR(result);
-    result = Dart_SetNativeResolver(library, GetNativeFunction, GetSymbol);
-    SHUTDOWN_ON_ERROR(result);
-  }
+  // Set the root library for the isolate.
+  Dart_Handle uri = Dart_NewStringFromCString("dart:vmservice_io");
+  Dart_Handle library = Dart_LookupLibrary(uri);
+  SHUTDOWN_ON_ERROR(library);
+  Dart_Handle result = Dart_SetRootLibrary(library);
+  SHUTDOWN_ON_ERROR(result);
+  result = Dart_SetNativeResolver(library, GetNativeFunction, GetSymbol);
+  SHUTDOWN_ON_ERROR(result);
 
   // Make runnable.
   Dart_ExitScope();
@@ -146,7 +127,7 @@ bool DartServiceIsolate::Startup(std::string server_ip,
   Dart_EnterIsolate(isolate);
   Dart_EnterScope();
 
-  Dart_Handle library = Dart_RootLibrary();
+  library = Dart_RootLibrary();
   SHUTDOWN_ON_ERROR(library);
 
   // Set the HTTP server's ip.
@@ -174,30 +155,6 @@ bool DartServiceIsolate::Startup(std::string server_ip,
   return true;
 }
 
-Dart_Handle DartServiceIsolate::GetSource(const char* name) {
-  const intptr_t kBufferSize = 512;
-  char buffer[kBufferSize];
-  snprintf(&buffer[0], kBufferSize - 1, "%s/%s", kLibrarySourceNamePrefix,
-           name);
-  const char* vmservice_source = NULL;
-  int r = g_resources->ResourceLookup(buffer, &vmservice_source);
-  FXL_DCHECK(r != EmbedderResources::kNoSuchInstance);
-  return Dart_NewStringFromCString(vmservice_source);
-}
-
-Dart_Handle DartServiceIsolate::LoadScript(const char* name) {
-  Dart_Handle url = Dart_NewStringFromCString("dart:vmservice_io");
-  Dart_Handle source = GetSource(name);
-  return Dart_LoadScript(url, Dart_Null(), source, 0, 0);
-}
-
-Dart_Handle DartServiceIsolate::LoadSource(Dart_Handle library,
-                                           const char* name) {
-  Dart_Handle url = Dart_NewStringFromCString(name);
-  Dart_Handle source = GetSource(name);
-  return Dart_LoadSource(library, url, Dart_Null(), source, 0, 0);
-}
-
 Dart_Handle DartServiceIsolate::LoadResource(Dart_Handle library,
                                              const char* resource_name) {
   // Prepare for invoke call.
@@ -248,41 +205,4 @@ Dart_Handle DartServiceIsolate::LoadResources(Dart_Handle library) {
   return result;
 }
 
-Dart_Handle DartServiceIsolate::LibraryTagHandler(Dart_LibraryTag tag,
-                                                  Dart_Handle library,
-                                                  Dart_Handle url) {
-  if (!Dart_IsLibrary(library)) {
-    return Dart_NewApiError("not a library");
-  }
-  if (!Dart_IsString(url)) {
-    return Dart_NewApiError("url is not a string");
-  }
-  const char* url_string = NULL;
-  Dart_Handle result = Dart_StringToCString(url, &url_string);
-  if (Dart_IsError(result)) {
-    return result;
-  }
-  Dart_Handle library_url = Dart_LibraryUrl(library);
-  const char* library_url_string = NULL;
-  result = Dart_StringToCString(library_url, &library_url_string);
-  if (Dart_IsError(result)) {
-    return result;
-  }
-  if (tag == Dart_kImportTag) {
-    // Embedder handles all requests for external libraries.
-    return g_embedder_tag_handler(tag, library, url);
-  }
-  FXL_DCHECK((tag == Dart_kSourceTag) || (tag == Dart_kCanonicalizeUrl));
-  if (tag == Dart_kCanonicalizeUrl) {
-    // url is already canonicalized.
-    return url;
-  }
-  // Get source from builtin resources.
-  Dart_Handle source = GetSource(url_string);
-  if (Dart_IsError(source)) {
-    return source;
-  }
-  return Dart_LoadSource(library, url, Dart_Null(), source, 0, 0);
-}
-
 }  // namespace blink

runtime/dart_service_isolate.h

@@ -16,7 +16,6 @@ class DartServiceIsolate {
   static bool Startup(std::string server_ip,
                       intptr_t server_port,
                       Dart_LibraryTagHandler embedder_tag_handler,
-                      bool running_from_sources,
                       bool disable_origin_check,
                       char** error);
 
@@ -28,14 +27,6 @@ class DartServiceIsolate {
   static void NotifyServerState(Dart_NativeArguments args);
   static void Shutdown(Dart_NativeArguments args);
 
-  // Script loading.
-  static Dart_Handle GetSource(const char* name);
-  static Dart_Handle LoadScript(const char* name);
-  static Dart_Handle LoadSource(Dart_Handle library, const char* name);
-  static Dart_Handle LibraryTagHandler(Dart_LibraryTag tag,
-                                       Dart_Handle library,
-                                       Dart_Handle url);
-
   // Observatory resource loading.
   static Dart_Handle LoadResources(Dart_Handle library);
   static Dart_Handle LoadResource(Dart_Handle library, const char* name);

runtime/dart_vm.cc

@@ -83,14 +83,6 @@ static const char* kDartAssertArgs[] = {
     // clang-format on
 };
 
-static const char* kDartCheckedModeArgs[] = {
-    // clang-format off
-    "--enable_type_checks",
-    "--error_on_bad_type",
-    "--error_on_bad_override",
-    // clang-format on
-};
-
 static const char* kDartStrongModeArgs[] = {
     // clang-format off
     "--strong",
@@ -324,18 +316,18 @@ DartVM::DartVM(const Settings& settings,
                 arraysize(kDartPrecompilationArgs));
   }
 
-  // Enable checked mode if we are not running precompiled code. We run non-
+  // Enable asserts if we are not running precompiled code. We run non-
   // precompiled code only in the debug product mode.
-  bool use_checked_mode = !settings.dart_non_checked_mode;
+  bool enable_asserts = true;
 
 #if FLUTTER_RUNTIME_MODE == FLUTTER_RUNTIME_MODE_DYNAMIC_PROFILE || \
     FLUTTER_RUNTIME_MODE == FLUTTER_RUNTIME_MODE_DYNAMIC_RELEASE
-  use_checked_mode = false;
+  enable_asserts = false;
 #endif
 
 #if !OS_FUCHSIA
   if (IsRunningPrecompiledCode()) {
-    use_checked_mode = false;
+    enable_asserts = false;
   }
 #endif  // !OS_FUCHSIA
 
@@ -346,29 +338,12 @@ DartVM::DartVM(const Settings& settings,
               arraysize(kDartWriteProtectCodeArgs));
 #endif
 
-  const bool isolate_snapshot_is_dart_2 =
-      Dart_IsDart2Snapshot(isolate_snapshot_->GetData()->GetSnapshotPointer());
+  // Require Dart 2.
+  FML_DCHECK(platform_kernel_mapping_->GetSize() > 0);
 
-  const bool is_preview_dart2 =
-      (platform_kernel_mapping_->GetSize() > 0) || isolate_snapshot_is_dart_2;
-
-  FXL_DLOG(INFO) << "Dart 2 " << (is_preview_dart2 ? "is" : "is NOT")
-                 << " enabled. Platform kernel: "
-                 << static_cast<bool>(platform_kernel_mapping_->GetSize() > 0)
-                 << " Isolate Snapshot is Dart 2: "
-                 << isolate_snapshot_is_dart_2;
-
-  if (is_preview_dart2) {
-    PushBackAll(&args, kDartStrongModeArgs, arraysize(kDartStrongModeArgs));
-    if (use_checked_mode) {
-      PushBackAll(&args, kDartAssertArgs, arraysize(kDartAssertArgs));
-    }
-  } else if (use_checked_mode) {
-    FXL_DLOG(INFO) << "Checked mode is ON";
+  PushBackAll(&args, kDartStrongModeArgs, arraysize(kDartStrongModeArgs));
+  if (enable_asserts) {
     PushBackAll(&args, kDartAssertArgs, arraysize(kDartAssertArgs));
-    PushBackAll(&args, kDartCheckedModeArgs, arraysize(kDartCheckedModeArgs));
-  } else {
-    FXL_DLOG(INFO) << "Is not Dart 2 and Checked mode is OFF";
   }
 
   if (settings.start_paused) {
@@ -390,6 +365,7 @@ DartVM::DartVM(const Settings& settings,
   PushBackAll(&args, kDartFuchsiaTraceArgs, arraysize(kDartFuchsiaTraceArgs));
 #endif
 
+  // Add VM dart_flags last to allow user overrides.
   for (size_t i = 0; i < settings.dart_flags.size(); i++)
     args.push_back(settings.dart_flags[i].c_str());
 

shell/common/isolate_configuration.cc

@@ -145,17 +145,6 @@ std::unique_ptr<IsolateConfiguration> IsolateConfiguration::InferFromSettings(
     }
   }
 
-  // Running from script snapshot.
-  {
-    // TODO(engine): Add AssetManager::GetAsMapping or such to avoid the copy.
-    std::vector<uint8_t> script_snapshot;
-    if (asset_manager && asset_manager->GetAsBuffer(
-                             settings.script_snapshot_path, &script_snapshot)) {
-      return CreateForSnapshot(
-          std::make_unique<fml::DataMapping>(std::move(script_snapshot)));
-    }
-  }
-
   // Running from kernel divided into several pieces (for sharing).
   {
     // TODO(fuchsia): Add AssetManager::GetAsMapping or such to avoid the copy.

shell/common/switches.cc

@@ -129,10 +129,6 @@ blink::Settings SettingsFromCommandLine(const fxl::CommandLine& command_line) {
     }
   }
 
-  // Checked mode overrides.
-  settings.dart_non_checked_mode =
-      command_line.HasOption(FlagForSwitch(Switch::DartNonCheckedMode));
-
   settings.ipv6 = command_line.HasOption(FlagForSwitch(Switch::IPv6));
 
   settings.start_paused =
@@ -161,9 +157,6 @@ blink::Settings SettingsFromCommandLine(const fxl::CommandLine& command_line) {
   command_line.GetOptionValue(FlagForSwitch(Switch::FlutterAssetsDir),
                               &settings.assets_path);
 
-  command_line.GetOptionValue(FlagForSwitch(Switch::Snapshot),
-                              &settings.script_snapshot_path);
-
   command_line.GetOptionValue(FlagForSwitch(Switch::MainDartFile),
                               &settings.main_dart_file_path);