- Add the ability to protect VirtualMemory.

runtime/vm/virtual_memory.h

 // Copyright (c) 2012, 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_VIRTUAL_MEMORY_H_
 #define VM_VIRTUAL_MEMORY_H_
 
 #include "platform/utils.h"
 #include "vm/globals.h"
 #include "vm/memory_region.h"
 
 namespace dart {
 
 class VirtualMemory {
  public:
+  enum Protection {
+    kNoAccess,
+    kReadOnly,
+    kReadWrite,
+    kReadExecute,
+    kReadWriteExecute
+  };
+
   // The reserved memory is unmapped on destruction.
   ~VirtualMemory();
 
   uword start() const { return region_.start(); }
   uword end() const { return region_.end(); }
   void* address() const { return region_.pointer(); }
   intptr_t size() const { return region_.size(); }
 
   static void InitOnce();
 
   bool Contains(uword addr) const {
     return region_.Contains(addr);
   }
 
   // Commits the virtual memory area.
   bool Commit(bool is_executable) {
     return Commit(start(), size(), is_executable);
   }
 
+  // Changes the protection of the virtual memory area.
+  bool Protect(Protection mode);
+
   // Reserves a virtual memory segment with size. If a segment of the requested
   // size cannot be allocated NULL is returned.
   static VirtualMemory* Reserve(intptr_t size);
 
   // Reserves a virtual memory segment with the start address being aligned to
   // the requested power of two.
   static VirtualMemory* ReserveAligned(intptr_t size, intptr_t alignment);
 
   static intptr_t PageSize() {
     ASSERT(page_size_ != 0);
@@ skipping 29 matching lines @@
   void* reserved_pointer_;
 
   static uword page_size_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(VirtualMemory);
 };
 
 }  // namespace dart
 
 #endif  // VM_VIRTUAL_MEMORY_H_