Load the native call wrapper via Thread.

runtime/vm/stub_code_x64.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 "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
@@ skipping 167 matching lines @@
   __ movq(Address(RSP, thread_offset), THR);  // Set thread in NativeArgs.
   __ movq(Address(RSP, argc_tag_offset), R10);  // Set argc in NativeArguments.
   __ movq(Address(RSP, argv_offset), RAX);  // Set argv in NativeArguments.
   __ leaq(RAX, Address(RBP, 2 * kWordSize));  // Compute return value addr.
   __ movq(Address(RSP, retval_offset), RAX);  // Set retval in NativeArguments.
 
   // Pass the pointer to the NativeArguments.
   __ movq(CallingConventions::kArg1Reg, RSP);
   // Pass pointer to function entrypoint.
   __ movq(CallingConventions::kArg2Reg, RBX);
-  __ LoadExternalLabel(
-      RAX, &NativeEntry::NativeCallWrapperLabel(), kNotPatchable);
+
+  __ movq(RAX, Address(THR, Thread::native_call_wrapper_entry_point_offset()));
   __ CallCFunction(RAX);
 
   // Mark that the isolate is executing Dart code.
   __ movq(Address(R12, Isolate::vm_tag_offset()),
           Immediate(VMTag::kDartTagId));
 
   // Reset exit frame information in Isolate structure.
   __ movq(Address(THR, Thread::top_exit_frame_info_offset()), Immediate(0));
 
   __ LeaveStubFrame();
@@ skipping 1957 matching lines @@
 // Result:
 //  RCX: entry point.
 void StubCode::GenerateMegamorphicLookupStub(Assembler* assembler) {
   EmitMegamorphicLookup(assembler, RDI, RBX, RCX);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64