Implement safepointing of threads

runtime/vm/native_arguments.h

 // 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.
 
 #ifndef VM_NATIVE_ARGUMENTS_H_
 #define VM_NATIVE_ARGUMENTS_H_
 
 #include "platform/assert.h"
 #include "platform/memory_sanitizer.h"
 #include "vm/globals.h"
@@ skipping 78 matching lines @@
   int ArgCount() const { return ArgcBits::decode(argc_tag_); }
 
   RawObject* ArgAt(int index) const {
     ASSERT((index >= 0) && (index < ArgCount()));
     RawObject** arg_ptr = &((*argv_)[-index]);
     // Tell MemorySanitizer the RawObject* was initialized (by generated code).
     MSAN_UNPOISON(arg_ptr, kWordSize);
     return *arg_ptr;
   }
 
+  bool IsNativeAutoSetupScope() const {
+    return AutoSetupScopeBits::decode(argc_tag_);
+  }
+
   int NativeArgCount() const {
     int function_bits = FunctionBits::decode(argc_tag_);
     return ArgCount() - NumHiddenArgs(function_bits);
   }
 
   RawObject* NativeArg0() const {
     int function_bits = FunctionBits::decode(argc_tag_);
     if (function_bits == (kClosureFunctionBit | kInstanceFunctionBit)) {
       // Retrieve the receiver from the context.
       const Object& closure = Object::Handle(ArgAt(0));
@@ skipping 114 matching lines @@
 
   Thread* thread_;  // Current thread pointer.
   int argc_tag_;  // Encodes argument count and invoked native call type.
   RawObject*(*argv_)[];  // Pointer to an array of arguments to runtime call.
   RawObject** retval_;  // Pointer to the return value area.
 };
 
 }  // namespace dart
 
 #endif  // VM_NATIVE_ARGUMENTS_H_