1 // Copyright 2013 The Flutter Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "flutter/runtime/dart_vm.h"
6
7 #include <sys/stat.h>
8
9 #include <mutex>
10 #include <vector>
11
12 #include "flutter/common/settings.h"
13 #include "flutter/fml/compiler_specific.h"
14 #include "flutter/fml/file.h"
15 #include "flutter/fml/logging.h"
16 #include "flutter/fml/mapping.h"
17 #include "flutter/fml/size.h"
18 #include "flutter/fml/synchronization/count_down_latch.h"
19 #include "flutter/fml/synchronization/thread_annotations.h"
20 #include "flutter/fml/time/time_delta.h"
21 #include "flutter/fml/trace_event.h"
22 #include "flutter/lib/io/dart_io.h"
23 #include "flutter/lib/ui/dart_runtime_hooks.h"
24 #include "flutter/lib/ui/dart_ui.h"
25 #include "flutter/runtime/dart_isolate.h"
26 #include "flutter/runtime/dart_service_isolate.h"
27 #include "flutter/runtime/ptrace_ios.h"
28 #include "flutter/runtime/start_up.h"
29 #include "third_party/dart/runtime/include/bin/dart_io_api.h"
30 #include "third_party/skia/include/core/SkExecutor.h"
31
32 namespace dart {
33 namespace observatory {
34
35 #if !OS_FUCHSIA && (FLUTTER_RUNTIME_MODE != FLUTTER_RUNTIME_MODE_RELEASE)
36
37 // These two symbols are defined in |observatory_archive.cc| which is generated
38 // by the |//third_party/dart/runtime/observatory:archive_observatory| rule.
39 // Both of these symbols will be part of the data segment and therefore are read
40 // only.
41 extern unsigned int observatory_assets_archive_len;
42 extern const uint8_t* observatory_assets_archive;
43
44 #endif // !OS_FUCHSIA && (FLUTTER_RUNTIME_MODE !=
45 // FLUTTER_RUNTIME_MODE_RELEASE)
46
47 } // namespace observatory
48 } // namespace dart
49
50 namespace flutter {
51
52 // Arguments passed to the Dart VM in all configurations.
53 static const char* kDartLanguageArgs[] = {
54 // clang-format off
55 "--enable_mirrors=false",
56 "--background_compilation",
57 "--causal_async_stacks",
58 // clang-format on
59 };
60
61 static const char* kDartPrecompilationArgs[] = {
62 "--precompilation",
63 };
64
65 FML_ALLOW_UNUSED_TYPE
66 static const char* kDartWriteProtectCodeArgs[] = {
67 "--no_write_protect_code",
68 };
69
70 FML_ALLOW_UNUSED_TYPE
71 static const char* kDartDisableIntegerDivisionArgs[] = {
72 "--no_use_integer_division",
73 };
74
75 static const char* kDartAssertArgs[] = {
76 // clang-format off
77 "--enable_asserts",
78 // clang-format on
79 };
80
81 static const char* kDartStartPausedArgs[]{
82 "--pause_isolates_on_start",
83 };
84
85 static const char* kDartDisableServiceAuthCodesArgs[]{
86 "--disable-service-auth-codes",
87 };
88
89 static const char* kDartTraceStartupArgs[]{
90 "--timeline_streams=Compiler,Dart,Debugger,Embedder,GC,Isolate,VM",
91 };
92
93 static const char* kDartEndlessTraceBufferArgs[]{
94 "--timeline_recorder=endless",
95 };
96
97 static const char* kDartSystraceTraceBufferArgs[]{
98 "--timeline_recorder=systrace",
99 };
100
101 static const char* kDartFuchsiaTraceArgs[] FML_ALLOW_UNUSED_TYPE = {
102 "--systrace_timeline",
103 };
104
105 static const char* kDartTraceStreamsArgs[] = {
106 "--timeline_streams=Compiler,Dart,Debugger,Embedder,GC,Isolate,VM",
107 };
108
109 constexpr char kFileUriPrefix[] = "file://";
110 constexpr size_t kFileUriPrefixLength = sizeof(kFileUriPrefix) - 1;
111
DartFileModifiedCallback(const char * source_url,int64_t since_ms)112 bool DartFileModifiedCallback(const char* source_url, int64_t since_ms) {
113 if (strncmp(source_url, kFileUriPrefix, kFileUriPrefixLength) != 0u) {
114 // Assume modified.
115 return true;
116 }
117
118 const char* path = source_url + kFileUriPrefixLength;
119 struct stat info;
120 if (stat(path, &info) < 0)
121 return true;
122
123 // If st_mtime is zero, it's more likely that the file system doesn't support
124 // mtime than that the file was actually modified in the 1970s.
125 if (!info.st_mtime)
126 return true;
127
128 // It's very unclear what time bases we're with here. The Dart API doesn't
129 // document the time base for since_ms. Reading the code, the value varies by
130 // platform, with a typical source being something like gettimeofday.
131 //
132 // We add one to st_mtime because st_mtime has less precision than since_ms
133 // and we want to treat the file as modified if the since time is between
134 // ticks of the mtime.
135 fml::TimeDelta mtime = fml::TimeDelta::FromSeconds(info.st_mtime + 1);
136 fml::TimeDelta since = fml::TimeDelta::FromMilliseconds(since_ms);
137
138 return mtime > since;
139 }
140
ThreadExitCallback()141 void ThreadExitCallback() {}
142
GetVMServiceAssetsArchiveCallback()143 Dart_Handle GetVMServiceAssetsArchiveCallback() {
144 #if (FLUTTER_RUNTIME_MODE == FLUTTER_RUNTIME_MODE_RELEASE)
145 return nullptr;
146 #elif OS_FUCHSIA
147 fml::UniqueFD fd = fml::OpenFile("pkg/data/observatory.tar", false,
148 fml::FilePermission::kRead);
149 fml::FileMapping mapping(fd, {fml::FileMapping::Protection::kRead});
150 if (mapping.GetSize() == 0 || mapping.GetMapping() == nullptr) {
151 FML_LOG(ERROR) << "Fail to load Observatory archive";
152 return nullptr;
153 }
154 return tonic::DartConverter<tonic::Uint8List>::ToDart(mapping.GetMapping(),
155 mapping.GetSize());
156 #else
157 return tonic::DartConverter<tonic::Uint8List>::ToDart(
158 ::dart::observatory::observatory_assets_archive,
159 ::dart::observatory::observatory_assets_archive_len);
160 #endif
161 }
162
163 static const char kStdoutStreamId[] = "Stdout";
164 static const char kStderrStreamId[] = "Stderr";
165
ServiceStreamListenCallback(const char * stream_id)166 static bool ServiceStreamListenCallback(const char* stream_id) {
167 if (strcmp(stream_id, kStdoutStreamId) == 0) {
168 dart::bin::SetCaptureStdout(true);
169 return true;
170 } else if (strcmp(stream_id, kStderrStreamId) == 0) {
171 dart::bin::SetCaptureStderr(true);
172 return true;
173 }
174 return false;
175 }
176
ServiceStreamCancelCallback(const char * stream_id)177 static void ServiceStreamCancelCallback(const char* stream_id) {
178 if (strcmp(stream_id, kStdoutStreamId) == 0) {
179 dart::bin::SetCaptureStdout(false);
180 } else if (strcmp(stream_id, kStderrStreamId) == 0) {
181 dart::bin::SetCaptureStderr(false);
182 }
183 }
184
IsRunningPrecompiledCode()185 bool DartVM::IsRunningPrecompiledCode() {
186 return Dart_IsPrecompiledRuntime();
187 }
188
ProfilingFlags(bool enable_profiling)189 static std::vector<const char*> ProfilingFlags(bool enable_profiling) {
190 // Disable Dart's built in profiler when building a debug build. This
191 // works around a race condition that would sometimes stop a crash's
192 // stack trace from being printed on Android.
193 #ifndef NDEBUG
194 enable_profiling = false;
195 #endif
196
197 // We want to disable profiling by default because it overwhelms LLDB. But
198 // the VM enables the same by default. In either case, we have some profiling
199 // flags.
200 if (enable_profiling) {
201 return {// This is the default. But just be explicit.
202 "--profiler",
203 // This instructs the profiler to walk C++ frames, and to include
204 // them in the profile.
205 "--profile-vm"};
206 } else {
207 return {"--no-profiler"};
208 }
209 }
210
PushBackAll(std::vector<const char * > * args,const char ** argv,size_t argc)211 void PushBackAll(std::vector<const char*>* args,
212 const char** argv,
213 size_t argc) {
214 for (size_t i = 0; i < argc; ++i) {
215 args->push_back(argv[i]);
216 }
217 }
218
EmbedderInformationCallback(Dart_EmbedderInformation * info)219 static void EmbedderInformationCallback(Dart_EmbedderInformation* info) {
220 info->version = DART_EMBEDDER_INFORMATION_CURRENT_VERSION;
221 dart::bin::GetIOEmbedderInformation(info);
222 info->name = "Flutter";
223 }
224
Create(Settings settings,fml::RefPtr<DartSnapshot> vm_snapshot,fml::RefPtr<DartSnapshot> isolate_snapshot,fml::RefPtr<DartSnapshot> shared_snapshot,std::shared_ptr<IsolateNameServer> isolate_name_server)225 std::shared_ptr<DartVM> DartVM::Create(
226 Settings settings,
227 fml::RefPtr<DartSnapshot> vm_snapshot,
228 fml::RefPtr<DartSnapshot> isolate_snapshot,
229 fml::RefPtr<DartSnapshot> shared_snapshot,
230 std::shared_ptr<IsolateNameServer> isolate_name_server) {
231 auto vm_data = DartVMData::Create(settings, //
232 std::move(vm_snapshot), //
233 std::move(isolate_snapshot), //
234 std::move(shared_snapshot) //
235 );
236
237 if (!vm_data) {
238 FML_LOG(ERROR) << "Could not setup VM data to bootstrap the VM from.";
239 return {};
240 }
241
242 // Note: std::make_shared unviable due to hidden constructor.
243 return std::shared_ptr<DartVM>(
244 new DartVM(std::move(vm_data), std::move(isolate_name_server)));
245 }
246
247 static std::atomic_size_t gVMLaunchCount;
248
GetVMLaunchCount()249 size_t DartVM::GetVMLaunchCount() {
250 return gVMLaunchCount;
251 }
252
DartVM(std::shared_ptr<const DartVMData> vm_data,std::shared_ptr<IsolateNameServer> isolate_name_server)253 DartVM::DartVM(std::shared_ptr<const DartVMData> vm_data,
254 std::shared_ptr<IsolateNameServer> isolate_name_server)
255 : settings_(vm_data->GetSettings()),
256 concurrent_message_loop_(fml::ConcurrentMessageLoop::Create()),
257 skia_concurrent_executor_(
258 [runner = concurrent_message_loop_->GetTaskRunner()](
259 fml::closure work) { runner->PostTask(work); }),
260 vm_data_(vm_data),
261 isolate_name_server_(std::move(isolate_name_server)),
262 service_protocol_(std::make_shared<ServiceProtocol>()) {
263 TRACE_EVENT0("flutter", "DartVMInitializer");
264
265 gVMLaunchCount++;
266
267 // Setting the executor is not thread safe but Dart VM initialization is. So
268 // this call is thread-safe.
269 SkExecutor::SetDefault(&skia_concurrent_executor_);
270
271 FML_DCHECK(vm_data_);
272 FML_DCHECK(isolate_name_server_);
273 FML_DCHECK(service_protocol_);
274
275 FML_DLOG(INFO) << "Attempting Dart VM launch for mode: "
276 << (IsRunningPrecompiledCode() ? "AOT" : "Interpreter");
277
278 {
279 TRACE_EVENT0("flutter", "dart::bin::BootstrapDartIo");
280 dart::bin::BootstrapDartIo();
281
282 if (!settings_.temp_directory_path.empty()) {
283 dart::bin::SetSystemTempDirectory(settings_.temp_directory_path.c_str());
284 }
285 }
286
287 std::vector<const char*> args;
288
289 // Instruct the VM to ignore unrecognized flags.
290 // There is a lot of diversity in a lot of combinations when it
291 // comes to the arguments the VM supports. And, if the VM comes across a flag
292 // it does not recognize, it exits immediately.
293 args.push_back("--ignore-unrecognized-flags");
294
295 for (auto* const profiler_flag :
296 ProfilingFlags(settings_.enable_dart_profiling)) {
297 args.push_back(profiler_flag);
298 }
299
300 PushBackAll(&args, kDartLanguageArgs, fml::size(kDartLanguageArgs));
301
302 if (IsRunningPrecompiledCode()) {
303 PushBackAll(&args, kDartPrecompilationArgs,
304 fml::size(kDartPrecompilationArgs));
305 }
306
307 // Enable Dart assertions if we are not running precompiled code. We run non-
308 // precompiled code only in the debug product mode.
309 bool enable_asserts = !settings_.disable_dart_asserts;
310
311 #if !OS_FUCHSIA
312 if (IsRunningPrecompiledCode()) {
313 enable_asserts = false;
314 }
315 #endif // !OS_FUCHSIA
316
317 #if (FLUTTER_RUNTIME_MODE == FLUTTER_RUNTIME_MODE_DEBUG)
318 #if !OS_IOS || TARGET_OS_SIMULATOR
319 // Debug mode uses the JIT, disable code page write protection to avoid
320 // memory page protection changes before and after every compilation.
321 PushBackAll(&args, kDartWriteProtectCodeArgs,
322 fml::size(kDartWriteProtectCodeArgs));
323 #else
324 EnsureDebuggedIOS(settings_);
325 #if TARGET_CPU_ARM
326 // Tell Dart in JIT mode to not use integer division on armv7
327 // Ideally, this would be detected at runtime by Dart.
328 // TODO(dnfield): Remove this code
329 // https://github.com/dart-lang/sdk/issues/24743
330 PushBackAll(&args, kDartDisableIntegerDivisionArgs,
331 fml::size(kDartDisableIntegerDivisionArgs));
332 #endif // TARGET_CPU_ARM
333 #endif // !OS_IOS || TARGET_OS_SIMULATOR
334 #endif // (FLUTTER_RUNTIME_MODE == FLUTTER_RUNTIME_MODE_DEBUG)
335
336 if (enable_asserts) {
337 PushBackAll(&args, kDartAssertArgs, fml::size(kDartAssertArgs));
338 }
339
340 if (settings_.start_paused) {
341 PushBackAll(&args, kDartStartPausedArgs, fml::size(kDartStartPausedArgs));
342 }
343
344 if (settings_.disable_service_auth_codes) {
345 PushBackAll(&args, kDartDisableServiceAuthCodesArgs,
346 fml::size(kDartDisableServiceAuthCodesArgs));
347 }
348
349 if (settings_.endless_trace_buffer || settings_.trace_startup) {
350 // If we are tracing startup, make sure the trace buffer is endless so we
351 // don't lose early traces.
352 PushBackAll(&args, kDartEndlessTraceBufferArgs,
353 fml::size(kDartEndlessTraceBufferArgs));
354 }
355
356 if (settings_.trace_systrace) {
357 PushBackAll(&args, kDartSystraceTraceBufferArgs,
358 fml::size(kDartSystraceTraceBufferArgs));
359 PushBackAll(&args, kDartTraceStreamsArgs, fml::size(kDartTraceStreamsArgs));
360 }
361
362 if (settings_.trace_startup) {
363 PushBackAll(&args, kDartTraceStartupArgs, fml::size(kDartTraceStartupArgs));
364 }
365
366 #if defined(OS_FUCHSIA)
367 PushBackAll(&args, kDartFuchsiaTraceArgs, fml::size(kDartFuchsiaTraceArgs));
368 PushBackAll(&args, kDartTraceStreamsArgs, fml::size(kDartTraceStreamsArgs));
369 #endif
370
371 for (size_t i = 0; i < settings_.dart_flags.size(); i++)
372 args.push_back(settings_.dart_flags[i].c_str());
373
374 char* flags_error = Dart_SetVMFlags(args.size(), args.data());
375 if (flags_error) {
376 FML_LOG(FATAL) << "Error while setting Dart VM flags: " << flags_error;
377 ::free(flags_error);
378 }
379
380 DartUI::InitForGlobal();
381
382 {
383 TRACE_EVENT0("flutter", "Dart_Initialize");
384 Dart_InitializeParams params = {};
385 params.version = DART_INITIALIZE_PARAMS_CURRENT_VERSION;
386 params.vm_snapshot_data = vm_data_->GetVMSnapshot().GetDataMapping();
387 params.vm_snapshot_instructions =
388 vm_data_->GetVMSnapshot().GetInstructionsMapping();
389 params.create_group = reinterpret_cast<decltype(params.create_group)>(
390 DartIsolate::DartIsolateGroupCreateCallback);
391 params.shutdown_isolate =
392 reinterpret_cast<decltype(params.shutdown_isolate)>(
393 DartIsolate::DartIsolateShutdownCallback);
394 params.cleanup_group = reinterpret_cast<decltype(params.cleanup_group)>(
395 DartIsolate::DartIsolateGroupCleanupCallback);
396 params.thread_exit = ThreadExitCallback;
397 params.get_service_assets = GetVMServiceAssetsArchiveCallback;
398 params.entropy_source = dart::bin::GetEntropy;
399 char* init_error = Dart_Initialize(¶ms);
400 if (init_error) {
401 FML_LOG(FATAL) << "Error while initializing the Dart VM: " << init_error;
402 ::free(init_error);
403 }
404 // Send the earliest available timestamp in the application lifecycle to
405 // timeline. The difference between this timestamp and the time we render
406 // the very first frame gives us a good idea about Flutter's startup time.
407 // Use a duration event so about:tracing will consider this event when
408 // deciding the earliest event to use as time 0.
409 if (engine_main_enter_ts != 0) {
410 Dart_TimelineEvent("FlutterEngineMainEnter", // label
411 engine_main_enter_ts, // timestamp0
412 engine_main_enter_ts, // timestamp1_or_async_id
413 Dart_Timeline_Event_Duration, // event type
414 0, // argument_count
415 nullptr, // argument_names
416 nullptr // argument_values
417 );
418 }
419 }
420
421 Dart_SetFileModifiedCallback(&DartFileModifiedCallback);
422
423 // Allow streaming of stdout and stderr by the Dart vm.
424 Dart_SetServiceStreamCallbacks(&ServiceStreamListenCallback,
425 &ServiceStreamCancelCallback);
426
427 Dart_SetEmbedderInformationCallback(&EmbedderInformationCallback);
428
429 if (settings_.dart_library_sources_kernel != nullptr) {
430 std::unique_ptr<fml::Mapping> dart_library_sources =
431 settings_.dart_library_sources_kernel();
432 // Set sources for dart:* libraries for debugging.
433 Dart_SetDartLibrarySourcesKernel(dart_library_sources->GetMapping(),
434 dart_library_sources->GetSize());
435 }
436
437 FML_DLOG(INFO) << "New Dart VM instance created. Instance count: "
438 << gVMLaunchCount;
439 }
440
~DartVM()441 DartVM::~DartVM() {
442 // Setting the executor is not thread safe but Dart VM shutdown is. So
443 // this call is thread-safe.
444 SkExecutor::SetDefault(nullptr);
445
446 if (Dart_CurrentIsolate() != nullptr) {
447 Dart_ExitIsolate();
448 }
449
450 char* result = Dart_Cleanup();
451
452 dart::bin::CleanupDartIo();
453
454 FML_CHECK(result == nullptr)
455 << "Could not cleanly shut down the Dart VM. Error: \"" << result
456 << "\".";
457 free(result);
458
459 FML_DLOG(INFO) << "Dart VM instance destroyed. Instance count: "
460 << gVMLaunchCount;
461 }
462
GetVMData() const463 std::shared_ptr<const DartVMData> DartVM::GetVMData() const {
464 return vm_data_;
465 }
466
GetSettings() const467 const Settings& DartVM::GetSettings() const {
468 return settings_;
469 }
470
GetServiceProtocol() const471 std::shared_ptr<ServiceProtocol> DartVM::GetServiceProtocol() const {
472 return service_protocol_;
473 }
474
GetIsolateNameServer() const475 std::shared_ptr<IsolateNameServer> DartVM::GetIsolateNameServer() const {
476 return isolate_name_server_;
477 }
478
479 std::shared_ptr<fml::ConcurrentTaskRunner>
GetConcurrentWorkerTaskRunner() const480 DartVM::GetConcurrentWorkerTaskRunner() const {
481 return concurrent_message_loop_->GetTaskRunner();
482 }
483
484 } // namespace flutter
485