Add guard pages in front of platform allocations

src/platform-win32.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 939 matching lines @@
 }
 
 
 void OS::Free(void* address, const size_t size) {
   // TODO(1240712): VirtualFree has a return value which is ignored here.
   VirtualFree(address, 0, MEM_RELEASE);
   USE(size);
 }
 
 
+void OS::Guard(void* address, const size_t size) {
+  DWORD oldprotect;
+  VirtualProtect(address, size, PAGE_READONLY | PAGE_GUARD, &oldprotect);
+}
+
+
 void OS::Sleep(int milliseconds) {
   ::Sleep(milliseconds);
 }
 
 
 void OS::Abort() {
   if (!IsDebuggerPresent()) {
 #ifdef _MSC_VER
     // Make the MSVCRT do a silent abort.
     _set_abort_behavior(0, _WRITE_ABORT_MSG);
@@ skipping 1056 matching lines @@
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SamplerThread::RemoveActiveSampler(this);
   SetActive(false);
 }
 
 
 } }  // namespace v8::internal