- Add the ability to protect VirtualMemory.

runtime/vm/pages.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_PAGES_H_
 #define VM_PAGES_H_
 
 #include "vm/freelist.h"
 #include "vm/globals.h"
 #include "vm/virtual_memory.h"
@@ skipping 39 matching lines @@
     }
     set_top(result + size);
     return result;
   }
 
   void VisitObjects(ObjectVisitor* visitor) const;
   void VisitObjectPointers(ObjectPointerVisitor* visitor) const;
 
   RawObject* FindObject(FindObjectVisitor* visitor) const;
 
+  void WriteProtect(bool read_only);
+
  private:
   static HeapPage* Initialize(VirtualMemory* memory, bool is_executable);
   static HeapPage* Allocate(intptr_t size, bool is_executable);
 
   // Deallocate the virtual memory backing this page. The page pointer to this
   // page becomes immediately inaccessible.
   void Deallocate();
 
   VirtualMemory* memory_;
   HeapPage* next_;
@@ skipping 116 matching lines @@
     return reinterpret_cast<HeapPage*>(
         RawObject::ToAddr(raw_obj) & ~(kPageSize -1));
   }
 
   void StartEndAddress(uword* start, uword* end) const;
 
   void EnableGrowthControl() {
     page_space_controller_.Enable();
   }
 
+  void WriteProtect(bool read_only);
+
  private:
   static const intptr_t kAllocatablePageSize = kPageSize - sizeof(HeapPage);
 
   void AllocatePage();
   void FreePage(HeapPage* page, HeapPage* previous_page);
   HeapPage* AllocateLargePage(intptr_t size);
   void FreeLargePage(HeapPage* page, HeapPage* previous_page);
   void FreePages(HeapPage* pages);
 
   static intptr_t LargePageSizeFor(intptr_t size);
@@ skipping 34 matching lines @@
   bool sweeping_;
 
   PageSpaceController page_space_controller_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PageSpace);
 };
 
 }  // namespace dart
 
 #endif  // VM_PAGES_H_