Do not embed is_auto_setup_scope into the compilation of native calls.

runtime/vm/native_entry.h

 // Copyright (c) 2011, 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 RUNTIME_VM_NATIVE_ENTRY_H_
 #define RUNTIME_VM_NATIVE_ENTRY_H_
 
 #include "platform/memory_sanitizer.h"
 
 #include "vm/allocation.h"
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/exceptions.h"
 #include "vm/native_arguments.h"
 #include "vm/verifier.h"
 
 #include "include/dart_api.h"
 
 namespace dart {
 
 // Forward declarations.
 class Class;
 class String;
 
+// We have three variants of native functions:
+//  - bootstrap natives, which are called directly from stub code. The callee is
+//    responsible for safepoint transitions and setting up handle scopes as
+//    needed. Only VM-defined natives are bootstrap natives; they cannot be
+//    defined by embedders or native extensions.
+//  - no scope natives, which are called through a wrapper function. The wrapper
+//    function handles the safepoint transition. The callee is responsible for
+//    setting up API scopes as needed.
+//  - auto scope natives, which are called through a wrapper function. The
+//    wrapper function handles the safepoint transition and sets up an API
+//    scope.
+
 typedef void (*NativeFunction)(NativeArguments* arguments);
 
 
 #define NATIVE_ENTRY_FUNCTION(name) BootstrapNatives::DN_##name
 
 #ifdef DEBUG
 #define SET_NATIVE_RETVAL(args, value)                                         \
   RawObject* retval = value;                                                   \
   ASSERT(retval->IsDartInstance());                                            \
   arguments->SetReturnUnsafe(retval);
@@ skipping 65 matching lines @@
 
   // Resolve specified dart native function to the actual native entrypoint.
   static NativeFunction ResolveNative(const Library& library,
                                       const String& function_name,
                                       int number_of_arguments,
                                       bool* auto_setup_scope);
   static const uint8_t* ResolveSymbolInLibrary(const Library& library,
                                                uword pc);
   static const uint8_t* ResolveSymbol(uword pc);
 
-  static uword NativeCallWrapperEntry();
-  static void NativeCallWrapper(Dart_NativeArguments args,
-                                Dart_NativeFunction func);
+  static uword NoScopeNativeCallWrapperEntry();
+  static void NoScopeNativeCallWrapper(Dart_NativeArguments args,
+                                       Dart_NativeFunction func);
+
+  static uword AutoScopeNativeCallWrapperEntry();
+  static void AutoScopeNativeCallWrapper(Dart_NativeArguments args,
+                                         Dart_NativeFunction func);
 
 // DBC does not support lazy native call linking.
 #if !defined(TARGET_ARCH_DBC)
   static uword LinkNativeCallEntry();
   static void LinkNativeCall(Dart_NativeArguments args);
 #endif
 
  private:
-  static void NativeCallWrapperNoStackCheck(Dart_NativeArguments args,
-                                            Dart_NativeFunction func);
+  static void NoScopeNativeCallWrapperNoStackCheck(Dart_NativeArguments args,
+                                                   Dart_NativeFunction func);
+  static void AutoScopeNativeCallWrapperNoStackCheck(Dart_NativeArguments args,
+                                                     Dart_NativeFunction func);
 
   static bool ReturnValueIsError(NativeArguments* arguments);
   static void PropagateErrors(NativeArguments* arguments);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_NATIVE_ENTRY_H_