Implement safepointing of threads

runtime/vm/dart_api_impl.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.
 
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "vm/class_finalizer.h"
@@ skipping 339 matching lines @@
   if (function.IsNull()) {
     return ApiError::New(String::Handle(String::New("")));
   }
   const Array& args = Array::Handle(Array::New(kNumArgs));
   args.SetAt(0, receiver);
   args.SetAt(1, argument);
   return DartEntry::InvokeFunction(function, args);
 }
 
 
+static const char* GetErrorString(Thread* thread, const Object& obj) {

[zra, 2016/01/13 22:16:13]

Does calling this require being in a DARTSCOPE()? If so, please add a comment
here.

[siva, 2016/01/27 19:07:50]

Added a comment that this function assumes an Api scope exists and added a
assert to ensure that.

+  if (obj.IsError()) {
+    const Error& error = Error::Cast(obj);
+    const char* str = error.ToErrorCString();
+    intptr_t len = strlen(str) + 1;
+    char* str_copy = Api::TopScope(thread)->zone()->Alloc<char>(len);
+    strncpy(str_copy, str, len);
+    // Strip a possible trailing '\n'.
+    if ((len > 1) && (str_copy[len - 2] == '\n')) {
+      str_copy[len - 2] = '\0';
+    }
+    return str_copy;
+  } else {
+    return "";
+  }
+}
+
+
 Dart_Handle Api::InitNewHandle(Thread* thread, RawObject* raw) {
   LocalHandles* local_handles = Api::TopScope(thread)->local_handles();
   ASSERT(local_handles != NULL);
   LocalHandle* ref = local_handles->AllocateHandle();
   ref->set_raw(raw);
   return ref->apiHandle();
 }
 
 
 Dart_Handle Api::NewHandle(Thread* thread, RawObject* raw) {
@@ skipping 74 matching lines @@
   return Api::NewHandle(thread, isolate->object_store()->sticky_error());
 }
 
 
 Dart_Isolate Api::CastIsolate(Isolate* isolate) {
   return reinterpret_cast<Dart_Isolate>(isolate);
 }
 
 
 Dart_Handle Api::NewError(const char* format, ...) {
-  DARTSCOPE(Thread::Current());
+  Thread* T = Thread::Current();
+  CHECK_API_SCOPE(T);
+  HANDLESCOPE(T);
   CHECK_CALLBACK_STATE(T);
 
   va_list args;
   va_start(args, format);
   intptr_t len = OS::VSNPrint(NULL, 0, format, args);
   va_end(args);
 
   char* buffer = Z->Alloc<char>(len + 1);
   va_list args2;
   va_start(args2, format);
@@ skipping 276 matching lines @@
   DARTSCOPE(Thread::Current());
   const Object& obj = Object::Handle(Z, Api::UnwrapHandle(handle));
   return (obj.IsUnwindError() && UnwindError::Cast(obj).is_vm_restart());
 }
 
 
 DART_EXPORT const char* Dart_GetError(Dart_Handle handle) {
   API_TIMELINE_DURATION;
   DARTSCOPE(Thread::Current());
   const Object& obj = Object::Handle(Z, Api::UnwrapHandle(handle));
-  if (obj.IsError()) {
-    const Error& error = Error::Cast(obj);
-    const char* str = error.ToErrorCString();
-    intptr_t len = strlen(str) + 1;
-    char* str_copy = Api::TopScope(T)->zone()->Alloc<char>(len);
-    strncpy(str_copy, str, len);
-    // Strip a possible trailing '\n'.
-    if ((len > 1) && (str_copy[len - 2] == '\n')) {
-      str_copy[len - 2] = '\0';
-    }
-    return str_copy;
-  } else {
-    return "";
-  }
+  return GetErrorString(T, obj);
 }
 
 
 DART_EXPORT bool Dart_ErrorHasException(Dart_Handle handle) {
   DARTSCOPE(Thread::Current());
   const Object& obj = Object::Handle(Z, Api::UnwrapHandle(handle));
   return obj.IsUnhandledException();
 }
 
 
@@ skipping 36 matching lines @@
 }
 
 
 DART_EXPORT Dart_Handle Dart_NewUnhandledExceptionError(Dart_Handle exception) {
   DARTSCOPE(Thread::Current());
   CHECK_CALLBACK_STATE(T);
 
   Instance& obj = Instance::Handle(Z);
   intptr_t class_id = Api::ClassId(exception);
   if ((class_id == kApiErrorCid) || (class_id == kLanguageErrorCid)) {
-    obj = String::New(::Dart_GetError(exception));
+    const Object& excp = Object::Handle(Z, Api::UnwrapHandle(exception));
+    obj = String::New(GetErrorString(T, excp));
   } else {
     obj = Api::UnwrapInstanceHandle(Z, exception).raw();
     if (obj.IsNull()) {
       RETURN_TYPE_ERROR(Z, exception, Instance);
     }
   }
   const Stacktrace& stacktrace = Stacktrace::Handle(Z);
   return Api::NewHandle(T, UnhandledException::New(obj, stacktrace));
 }
 
@@ skipping 194 matching lines @@
 DART_EXPORT Dart_WeakPersistentHandle Dart_NewWeakPersistentHandle(
     Dart_Handle object,
     void* peer,
     intptr_t external_allocation_size,
     Dart_WeakPersistentHandleFinalizer callback) {
   Thread* thread = Thread::Current();
   CHECK_ISOLATE(thread->isolate());
   if (callback == NULL) {
     return NULL;
   }
+  TransitionNativeToVM transition(thread);
   return AllocateFinalizableHandle(thread,
                                    object,
                                    peer,
                                    external_allocation_size,
                                    callback);
 }
 
 
 DART_EXPORT void Dart_DeletePersistentHandle(Dart_PersistentHandle object) {
   Isolate* isolate = Isolate::Current();
@@ skipping 198 matching lines @@
     const Error& error_obj =
         Error::Handle(Z, Dart::InitializeIsolate(snapshot, callback_data));
     if (error_obj.IsNull()) {
   #if defined(DART_NO_SNAPSHOT)
       if (FLAG_check_function_fingerprints) {
         Library::CheckFunctionFingerprints();
       }
   #endif  // defined(DART_NO_SNAPSHOT).
       // We exit the API scope entered above.
       Dart_ExitScope();
+      // A Thread structure has been associated to the thread, we do the
+      // safepoint transition explicity here instead of using the
+      // TransitionXXX scope objects as the reverse transition happens
+      // outside this scope in Dart_ShutdownIsolate/Dart_ExitIsolate.
+      T->set_execution_state(Thread::kThreadInNative);
+      T->EnterSafepoint();
       return Api::CastIsolate(I);
     }
     *error = strdup(error_obj.ToErrorCString());
     // We exit the API scope entered above.
     Dart_ExitScope();
   }
   Dart::ShutdownIsolate();
   return reinterpret_cast<Dart_Isolate>(NULL);
 }
 
 
 DART_EXPORT void Dart_ShutdownIsolate() {
   Thread* T = Thread::Current();
   Isolate* I = T->isolate();
   CHECK_ISOLATE(I);
   I->WaitForOutstandingSpawns();
   {
     StackZone zone(T);
     HandleScope handle_scope(T);
     Dart::RunShutdownCallback();
   }
+  // The Thread structure is disassociated from the isolate, we do the
+  // safepoint transition explicity here instead of using the TransitionXXX
+  // scope objects as the original transition happened outside this scope in
+  // Dart_EnterIsolate/Dart_CreateIsolate.
+  T->ExitSafepoint();
+  T->set_execution_state(Thread::kThreadInVM);
   Dart::ShutdownIsolate();
 }
 
 
 DART_EXPORT Dart_Isolate Dart_CurrentIsolate() {
   return Api::CastIsolate(Isolate::Current());
 }
 
 
 DART_EXPORT void* Dart_CurrentIsolateData() {
@@ skipping 23 matching lines @@
 DART_EXPORT void Dart_EnterIsolate(Dart_Isolate isolate) {
   CHECK_NO_ISOLATE(Isolate::Current());
   // TODO(16615): Validate isolate parameter.
   Isolate* iso = reinterpret_cast<Isolate*>(isolate);
   if (iso->HasMutatorThread()) {
     FATAL("Multiple mutators within one isolate is not supported.");
   }
   if (!Thread::EnterIsolate(iso)) {
     FATAL("Unable to Enter Isolate as Dart VM is shutting down");
   }
+  // A Thread structure has been associated to the thread, we do the
+  // safepoint transition explicity here instead of using the
+  // TransitionXXX scope objects as the reverse transition happens
+  // outside this scope in Dart_ExitIsolate/Dart_ShutdownIsolate.
+  Thread* T = Thread::Current();
+  T->set_execution_state(Thread::kThreadInNative);
+  T->EnterSafepoint();
 }
 
 
 DART_EXPORT void Dart_ThreadDisableProfiling() {
   OSThread* os_thread = OSThread::Current();
   if (os_thread == NULL) {
     return;
   }
   os_thread->DisableThreadInterrupts();
 }
 
 
 DART_EXPORT void Dart_ThreadEnableProfiling() {
   OSThread* os_thread = OSThread::Current();
   if (os_thread == NULL) {
     return;
   }
   os_thread->EnableThreadInterrupts();
 }
 
 
 DART_EXPORT void Dart_ExitIsolate() {
-  CHECK_ISOLATE(Isolate::Current());
+  Thread* T = Thread::Current();
+  CHECK_ISOLATE(T->isolate());
+  // The Thread structure is disassociated from the isolate, we do the
+  // safepoint transition explicity here instead of using the TransitionXXX
+  // scope objects as the original transition happened outside this scope in
+  // Dart_EnterIsolate/Dart_CreateIsolate.
+  ASSERT(T->execution_state() == Thread::kThreadInNative);
+  T->ExitSafepoint();
+  T->set_execution_state(Thread::kThreadInVM);
   Thread::ExitIsolate();
 }
 
 
 static uint8_t* ApiReallocate(uint8_t* ptr,
                               intptr_t old_size,
                               intptr_t new_size) {
   return Api::TopScope(Thread::Current())->zone()->Realloc<uint8_t>(
       ptr, old_size, new_size);
 }
@@ skipping 145 matching lines @@
   Thread* T = Thread::Current();
   Isolate* I = T->isolate();
   CHECK_API_SCOPE(T);
   CHECK_CALLBACK_STATE(T);
   API_TIMELINE_BEGIN_END;
   Monitor monitor;
   MonitorLocker ml(&monitor);
   {
     // The message handler run loop does not expect to have a current isolate
     // so we exit the isolate here and enter it again after the runloop is done.
-    Thread::ExitIsolate();
+    Dart_ExitIsolate();
     RunLoopData data;
     data.monitor = &monitor;
     data.done = false;
     I->message_handler()->Run(
         Dart::thread_pool(),
         NULL, RunLoopDone, reinterpret_cast<uword>(&data));
     while (!data.done) {
       ml.Wait();
     }
-    if (!Thread::EnterIsolate(I)) {
-      FATAL("Inconsistent state, VM shutting down while in run loop.");
-    }
+    Dart_EnterIsolate(Api::CastIsolate(I));
   }
   if (I->object_store()->sticky_error() != Object::null()) {
     Dart_Handle error = Api::NewHandle(T, I->object_store()->sticky_error());
     I->object_store()->clear_sticky_error();
     return error;
   }
   if (FLAG_print_class_table) {
     HANDLESCOPE(T);
     I->class_table()->Print();
   }
   return Api::Success();
 }
 
 
 DART_EXPORT Dart_Handle Dart_HandleMessage() {
   Thread* T = Thread::Current();
   Isolate* I = T->isolate();
   CHECK_API_SCOPE(T);
   CHECK_CALLBACK_STATE(T);
   API_TIMELINE_BEGIN_END;
+  TransitionNativeToVM trainsition(T);
   if (I->message_handler()->HandleNextMessage() != MessageHandler::kOK) {
     Dart_Handle error = Api::NewHandle(T, I->object_store()->sticky_error());
     I->object_store()->clear_sticky_error();
     return error;
   }
   return Api::Success();
 }
 
 
 DART_EXPORT bool Dart_HandleServiceMessages() {
   Thread* T = Thread::Current();
   Isolate* I = T->isolate();
   CHECK_API_SCOPE(T);
   CHECK_CALLBACK_STATE(T);
   API_TIMELINE_DURATION;
+  TransitionNativeToVM trainsition(T);
   ASSERT(I->GetAndClearResumeRequest() == false);
   MessageHandler::MessageStatus status =
       I->message_handler()->HandleOOBMessages();
   bool resume = I->GetAndClearResumeRequest();
   return (status != MessageHandler::kOK) || resume;
 }
 
 
 DART_EXPORT bool Dart_HasServiceMessages() {
   Isolate* isolate = Isolate::Current();
@@ skipping 3257 matching lines @@
   ASSERT(isolate->api_state() != NULL &&
          (isolate->api_state()->IsValidWeakPersistentHandle(rval)));
 #endif
   Api::SetWeakHandleReturnValue(arguments, rval);
 }
 
 
 // --- Environment ---
 RawString* Api::CallEnvironmentCallback(Thread* thread, const String& name) {
   Isolate* isolate = thread->isolate();
-  Scope api_scope(thread);
   Dart_EnvironmentCallback callback = isolate->environment_callback();
   String& result = String::Handle(thread->zone());
   if (callback != NULL) {
+    TransitionVMToNative transition(thread);
+    Scope api_scope(thread);
     Dart_Handle response = callback(Api::NewHandle(thread, name.raw()));
     if (::Dart_IsString(response)) {
       result ^= Api::UnwrapHandle(response);
     } else if (::Dart_IsError(response)) {
       const Object& error = Object::Handle(
           thread->zone(), Api::UnwrapHandle(response));
       Exceptions::ThrowArgumentError(
           String::Handle(String::New(Error::Cast(error).ToErrorCString())));
     } else if (!::Dart_IsNull(response)) {
       // At this point everything except null are invalid environment values.
@@ skipping 1133 matching lines @@
   return Api::Success();
 }
 #endif  // DART_PRECOMPILED
 
 
 DART_EXPORT bool Dart_IsRunningPrecompiledCode() {
   return Dart::IsRunningPrecompiledCode();
 }
 
 }  // namespace dart