[not for landing] Diff between a64 and r19234 for no-a64 files.

src/vm-state-inl.h

Index: src/vm-state-inl.h
diff --git a/src/vm-state-inl.h b/src/vm-state-inl.h
index 658773e6d6a8e06a026ae4fa9ca33a61cac3be14..41690345cb987bceab7fad805732b480a61ec80e 100644
--- a/src/vm-state-inl.h
+++ b/src/vm-state-inl.h
@@ -85,9 +85,13 @@ ExternalCallbackScope::ExternalCallbackScope(Isolate* isolate, Address callback)
       callback_(callback),
       previous_scope_(isolate->external_callback_scope()) {
 #ifdef USE_SIMULATOR
+#if V8_TARGET_ARCH_A64
+  scope_address_ = reinterpret_cast<Address>(Simulator::current(isolate)->sp());
+#else
   int32_t sp = Simulator::current(isolate)->get_register(Simulator::sp);
   scope_address_ = reinterpret_cast<Address>(static_cast<intptr_t>(sp));
 #endif
+#endif
   isolate_->set_external_callback_scope(this);
 }