Ensure that executable pages are properly guarded.

src/platform-openbsd.cc

 // Copyright 2012 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 440 matching lines @@
 bool VirtualMemory::Commit(void* address, size_t size, bool is_executable) {
   return CommitRegion(address, size, is_executable);
 }
 
 
 bool VirtualMemory::Uncommit(void* address, size_t size) {
   return UncommitRegion(address, size);
 }
 
 
+bool VirtualMemory::Guard(void* address) {
+  OS::Guard(address, OS::CommitPageSize());
+  return true;
+}
+
+
 void* VirtualMemory::ReserveRegion(size_t size) {
   void* result = mmap(GetRandomMmapAddr(),
                       size,
                       PROT_NONE,
                       MAP_PRIVATE | MAP_ANON | MAP_NORESERVE,
                       kMmapFd,
                       kMmapFdOffset);
 
   if (result == MAP_FAILED) return NULL;
 
@@ skipping 482 matching lines @@
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SignalSender::RemoveActiveSampler(this);
   SetActive(false);
 }
 
 
 } }  // namespace v8::internal