- Add the ability to protect VirtualMemory.

runtime/vm/virtual_memory_macos.cc

 // 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.
 
 #include "vm/virtual_memory.h"
 
 #include <sys/mman.h>
 #include <unistd.h>
 
 #include "platform/assert.h"
@@ skipping 54 matching lines @@
   int prot = PROT_READ | PROT_WRITE | (executable ? PROT_EXEC : 0);
   void* address = mmap(reinterpret_cast<void*>(addr), size, prot,
                        MAP_PRIVATE | MAP_ANON | MAP_FIXED,
                        -1, 0);
   if (address == MAP_FAILED) {
     return false;
   }
   return true;
 }
 
+
+bool VirtualMemory::Protect(Protection mode) {
+  int prot = 0;
+  switch (mode) {
+    case kNoAccess:
+      prot = PROT_NONE;
+      break;
+    case kReadOnly:
+      prot = PROT_READ;
+      break;
+    case kReadWrite:
+      prot = PROT_READ | PROT_WRITE;
+      break;
+    case kReadExecute:
+      prot = PROT_READ | PROT_EXEC;
+      break;
+    case kReadWriteExecute:
+      prot = PROT_READ | PROT_WRITE | PROT_EXEC;
+      break;
+  }
+  return (mprotect(address(), size(), prot) == 0);
+}
+
 }  // namespace dart