[simulator] Make reference redirection thread-safe.

src/arm64/simulator-arm64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdlib.h>
 #include <cmath>
 #include <cstdarg>
 
 #if V8_TARGET_ARCH_ARM64
 
@@ skipping 783 matching lines @@
   }
 
   set_lr(return_address);
   set_pc(return_address);
 }
 
 
 void* Simulator::RedirectExternalReference(Isolate* isolate,
                                            void* external_function,
                                            ExternalReference::Type type) {
+  base::LockGuard<base::Mutex> lock_guard(
+      isolate->simulator_redirection_mutex());
   Redirection* redirection = Redirection::Get(isolate, external_function, type);
   return redirection->address_of_redirect_call();
 }
 
 
 const char* Simulator::xreg_names[] = {
 "x0",  "x1",  "x2",  "x3",  "x4",   "x5",  "x6",  "x7",
 "x8",  "x9",  "x10", "x11", "x12",  "x13", "x14", "x15",
 "ip0", "ip1", "x18", "x19", "x20",  "x21", "x22", "x23",
 "x24", "x25", "x26", "cp",  "jssp", "fp",  "lr",  "xzr", "csp"};
@@ skipping 3388 matching lines @@
   processor->prev_ = nullptr;
   processor->next_ = nullptr;
 }
 
 #endif  // USE_SIMULATOR
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM64