Implement safepointing of threads

runtime/vm/object.cc

 // Copyright (c) 2012, 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/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 2761 matching lines @@
 
  private:
   const Class& cls_;
   DISALLOW_COPY_AND_ASSIGN(CHACodeArray);
 };
 
 
 #if defined(DEBUG)
 static bool IsMutatorOrAtSafepoint() {
   Thread* thread = Thread::Current();
-  return thread->IsMutatorThread() ||
-         thread->isolate()->thread_registry()->AtSafepoint();
+  return thread->IsMutatorThread() || thread->IsAtSafepoint();
 }
 #endif
 
 
 void Class::RegisterCHACode(const Code& code) {
   if (FLAG_trace_cha) {
     THR_Print("RegisterCHACode '%s' depends on class '%s'\n",
         Function::Handle(code.function()).ToQualifiedCString(), ToCString());
   }
   DEBUG_ASSERT(IsMutatorOrAtSafepoint());
@@ skipping 7891 matching lines @@
   // - invalidate dependent code of this prefix;
   // - mark this prefixes as loaded;
   // - complete the future associated with this prefix.
   const Library& deferred_lib = Library::Handle(GetLibrary(0));
   if (deferred_lib.Loaded()) {
     this->set_is_loaded();
     return true;
   } else if (deferred_lib.LoadNotStarted()) {
     Thread* thread = Thread::Current();
     Isolate* isolate = thread->isolate();
-    Api::Scope api_scope(thread);
     Zone* zone = thread->zone();
     deferred_lib.SetLoadRequested();
     const GrowableObjectArray& pending_deferred_loads =
         GrowableObjectArray::Handle(
             isolate->object_store()->pending_deferred_loads());
     pending_deferred_loads.Add(deferred_lib);
     const String& lib_url = String::Handle(zone, deferred_lib.url());
     Dart_LibraryTagHandler handler = isolate->library_tag_handler();
-    handler(Dart_kImportTag,
-            Api::NewHandle(thread, importer()),
-            Api::NewHandle(thread, lib_url.raw()));
+    {
+      TransitionVMToNative transition(thread);
+      Api::Scope api_scope(thread);
+      handler(Dart_kImportTag,
+              Api::NewHandle(thread, importer()),
+              Api::NewHandle(thread, lib_url.raw()));
+    }
   } else {
     // Another load request is in flight.
     ASSERT(deferred_lib.LoadRequested());
   }
   return false;  // Load request not yet completed.
 }
 
 
 RawArray* LibraryPrefix::dependent_code() const {
   return raw_ptr()->dependent_code_;
@@ skipping 12120 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart