Refactor Thread lifecycle interface, add Thread::Enter/ExitIsolate.

runtime/vm/thread.cc

 // Copyright (c) 2015, 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 "vm/thread.h"
 
 #include "vm/isolate.h"
 #include "vm/os_thread.h"
+#include "vm/profiler.h"
+#include "vm/thread_interrupter.h"
 
 
 namespace dart {
 
 // The single thread local key which stores all the thread local data
 // for a thread.
 // TODO(koda): Can we merge this with ThreadInterrupter::thread_state_key_?
 ThreadLocalKey Thread::thread_key_ = OSThread::kUnsetThreadLocalKey;
 
 
 void Thread::InitOnce() {
   ASSERT(thread_key_ == OSThread::kUnsetThreadLocalKey);
   thread_key_ = OSThread::CreateThreadLocal();
   ASSERT(thread_key_ != OSThread::kUnsetThreadLocalKey);
 }
 
 
 void Thread::SetCurrent(Thread* current) {
   OSThread::SetThreadLocal(thread_key_, reinterpret_cast<uword>(current));
 }
 
+
+void Thread::EnsureInit() {
+  if (Thread::Current() == NULL) {
+    SetCurrent(new Thread());
+  }
+}
+
+
+void Thread::CleanUp() {
+  // We currently deallocate the Thread, to ensure that embedder threads don't
+  // leak the Thread structure. An alternative approach would be to clear and
+  // reuse it, but register a destructor at the OS level.
+  Thread* current = Current();
+  if (current != NULL) {
+    delete current;
+  }
+  SetCurrent(NULL);
+}
+
+
+void Thread::EnterIsolate(Isolate* isolate) {
+  EnsureInit();
+  Thread* thread = Thread::Current();
+  ASSERT(thread->isolate() == NULL);
+  ASSERT(isolate->mutator_thread() == NULL);
+  isolate->set_mutator_thread(thread);
+  // TODO(koda): Migrate thread_state_ and profile_data_ to Thread, to allow
+  // helper threads concurrent with mutator.
+  ASSERT(isolate->thread_state() == NULL);
+  InterruptableThreadState* thread_state =
+      ThreadInterrupter::GetCurrentThreadState();
+#if defined(DEBUG)
+  Isolate::CheckForDuplicateThreadState(thread_state);
+#endif
+  ASSERT(thread_state != NULL);
+  Profiler::BeginExecution(isolate);
+  isolate->set_thread_state(thread_state);
+  isolate->set_vm_tag(VMTag::kVMTagId);
+  thread->isolate_ = isolate;
+}
+
+
+void Thread::ExitIsolate() {
+  Thread* thread = Thread::Current();
+  // TODO(koda): Audit callers; they should know whether they're in an isolate.
+  if (thread == NULL) return;
+  Isolate* isolate = thread->isolate();
+  ASSERT(isolate != NULL);
+  isolate->set_vm_tag(VMTag::kIdleTagId);
+  isolate->set_thread_state(NULL);
+  Profiler::EndExecution(isolate);
+  isolate->set_mutator_thread(NULL);
+  thread->isolate_ = NULL;
+  ASSERT(Isolate::Current() == NULL);
+  CleanUp();
+}
+
+
 }  // namespace dart