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

src/heap.cc

 // 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 2843 matching lines @@
 
 void Heap::Shrink() {
   // Try to shrink map, old, and code spaces.
   map_space_->Shrink();
   old_pointer_space_->Shrink();
   old_data_space_->Shrink();
   code_space_->Shrink();
 }
 
 
+#ifdef ENABLE_HEAP_PROTECTION
+
+void Heap::Protect() {
+  new_space_.Protect();
+  map_space_->Protect();
+  old_pointer_space_->Protect();
+  old_data_space_->Protect();
+  code_space_->Protect();
+  lo_space_->Protect();
+}
+
+
+void Heap::Unprotect() {
+  new_space_.Unprotect();
+  map_space_->Unprotect();
+  old_pointer_space_->Unprotect();
+  old_data_space_->Unprotect();
+  code_space_->Unprotect();
+  lo_space_->Unprotect();
+}
+
+#endif
+
+
 #ifdef DEBUG
 
 class PrintHandleVisitor: public ObjectVisitor {
  public:
   void VisitPointers(Object** start, Object** end) {
     for (Object** p = start; p < end; p++)
       PrintF("  handle %p to %p\n", p, *p);
   }
 };
 
@@ skipping 452 matching lines @@
 #ifdef DEBUG
 bool Heap::GarbageCollectionGreedyCheck() {
   ASSERT(FLAG_gc_greedy);
   if (Bootstrapper::IsActive()) return true;
   if (disallow_allocation_failure()) return true;
   return CollectGarbage(0, NEW_SPACE);
 }
 #endif
 
 } }  // namespace v8::internal