Ensure that executable pages are properly guarded.

src/spaces-inl.h

 // Copyright 2011 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 148 matching lines @@
 
 // --------------------------------------------------------------------------
 // PagedSpace
 Page* Page::Initialize(Heap* heap,
                        MemoryChunk* chunk,
                        Executability executable,
                        PagedSpace* owner) {
   Page* page = reinterpret_cast<Page*>(chunk);
   ASSERT(chunk->size() == static_cast<size_t>(kPageSize));
   ASSERT(chunk->owner() == owner);
-  owner->IncreaseCapacity(Page::kObjectAreaSize);
-  owner->Free(page->ObjectAreaStart(),
-              static_cast<int>(page->ObjectAreaEnd() -
-                               page->ObjectAreaStart()));
+  owner->IncreaseCapacity(page->area_size());
+  owner->Free(page->area_start(), page->area_size());
 
   heap->incremental_marking()->SetOldSpacePageFlags(chunk);
 
   return page;
 }
 
 
 bool PagedSpace::Contains(Address addr) {
   Page* p = Page::FromAddress(addr);
   if (!p->is_valid()) return false;
@@ skipping 158 matching lines @@
   Map* map = object->map();
   Heap* heap = object->GetHeap();
   return map == heap->raw_unchecked_free_space_map()
       || map == heap->raw_unchecked_one_pointer_filler_map()
       || map == heap->raw_unchecked_two_pointer_filler_map();
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_SPACES_INL_H_