Add basic infrastructure for protecting V8's heap when leaving the VM...

src/platform.h

 // 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 150 matching lines @@
   // output. On platforms that has standard terminal output, the output
   // should go to stderr.
   static void PrintError(const char* format, ...);
   static void VPrintError(const char* format, va_list args);
 
   // Allocate/Free memory used by JS heap. Pages are readable/writable, but
   // they are not guaranteed to be executable unless 'executable' is true.
   // Returns the address of allocated memory, or NULL if failed.
   static void* Allocate(const size_t requested,
                         size_t* allocated,
-                        bool executable);
-  static void Free(void* buf, const size_t length);
+                        bool is_executable);
+  static void Free(void* address, const size_t size);
   // Get the Alignment guaranteed by Allocate().
   static size_t AllocateAlignment();
 
+#ifdef ENABLE_HEAP_PROTECTION
+  // Protect/unprotect a block of memory by marking it read-only/writable.
+  static void Protect(void* address, size_t size);
+  static void Unprotect(void* address, size_t size, bool is_executable);
+#endif
+
   // Returns an indication of whether a pointer is in a space that
   // has been allocated by Allocate().  This method may conservatively
   // always return false, but giving more accurate information may
   // improve the robustness of the stack dump code in the presence of
   // heap corruption.
   static bool IsOutsideAllocatedSpace(void* pointer);
 
   // Sleep for a number of milliseconds.
   static void Sleep(const int milliseconds);
 
@@ skipping 74 matching lines @@
   // Returns the start address of the reserved memory.
   void* address() {
     ASSERT(IsReserved());
     return address_;
   };
 
   // Returns the size of the reserved memory.
   size_t size() { return size_; }
 
   // Commits real memory. Returns whether the operation succeeded.
-  bool Commit(void* address, size_t size, bool executable);
+  bool Commit(void* address, size_t size, bool is_executable);
 
   // Uncommit real memory.  Returns whether the operation succeeded.
   bool Uncommit(void* address, size_t size);
 
  private:
   void* address_;  // Start address of the virtual memory.
   size_t size_;  // Size of the virtual memory.
 };
 
 
@@ skipping 229 matching lines @@
   bool active_;
   PlatformData* data_;  // Platform specific data.
   DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);
 };
 
 #endif  // ENABLE_LOGGING_AND_PROFILING
 
 } }  // namespace v8::internal
 
 #endif  // V8_PLATFORM_H_