Split an allocation policy into an allocator and a deallocator.

src/zone-inl.h

 // Copyright 2012 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 72 matching lines @@
   segment_bytes_allocated_ += delta;
   isolate_->counters()->zone_segment_bytes()->Set(segment_bytes_allocated_);
 }
 
 
 template <typename Config>
 ZoneSplayTree<Config>::~ZoneSplayTree() {
   // Reset the root to avoid unneeded iteration over all tree nodes
   // in the destructor.  For a zone-allocated tree, nodes will be
   // freed by the Zone.
-  SplayTree<Config, ZoneListAllocationPolicy>::ResetRoot();
+  SplayTree<Config, ZoneAllocationPolicy>::ResetRoot();
 }
 
 
 // TODO(isolates): for performance reasons, this should be replaced with a new
 //                 operator that takes the zone in which the object should be
 //                 allocated.
 void* ZoneObject::operator new(size_t size) {
   return ZONE->New(static_cast<int>(size));
 }
 
 void* ZoneObject::operator new(size_t size, Zone* zone) {
   return zone->New(static_cast<int>(size));
 }
 
 
-inline void* ZoneListAllocationPolicy::New(int size) {
+void* ZoneAllocator::New(int size) {
   return ZONE->New(size);
 }
 
 
-template <typename T>
-void* ZoneList<T>::operator new(size_t size) {
-  return ZONE->New(static_cast<int>(size));
-}
-
-
+// The ZoneAllocator is used to specialize the List implementation to
+// allocate ZoneLists and their elements in the current Zone.

[danno, 2012/05/25 11:03:37]

Does the comment apply to the following code?  I'm confused a bit.

 template <typename T>
 void* ZoneList<T>::operator new(size_t size, Zone* zone) {
   return zone->New(static_cast<int>(size));
 }
 
 
+// De-allocation attempts are silently ignored.

[danno, 2012/05/25 11:03:37]

This comment seems unrelated?

+template<typename T>
+void* ZoneList<T>::operator new(size_t size) {
+  return List<T, ZoneAllocationPolicy>::operator new(size);

[danno, 2012/05/25 11:03:37]

Why did you move this function?  And why does it need to change (you will be
eliminating it in the next step anyway, and this seems premature and unrelated
to the other changes you are making in this CL.

+}
+
+
 ZoneScope::ZoneScope(Isolate* isolate, ZoneScopeMode mode)
     : isolate_(isolate), mode_(mode) {
   isolate_->zone()->scope_nesting_++;
 }
 
 
 bool ZoneScope::ShouldDeleteOnExit() {
   return isolate_->zone()->scope_nesting_ == 1 && mode_ == DELETE_ON_EXIT;
 }
 
 
 int ZoneScope::nesting() {
   return Isolate::Current()->zone()->scope_nesting_;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ZONE_INL_H_