Refactor allocation policies.

src/list.h

 // Copyright 2011 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 27 matching lines @@
 // The list is a template for very light-weight lists. We are not
 // using the STL because we want full control over space and speed of
 // the code. This implementation is based on code by Robert Griesemer
 // and Rob Pike.
 //
 // The list is parameterized by the type of its elements (T) and by an
 // allocation policy (P). The policy is used for allocating lists in
 // the C free store or the zone; see zone.h.
 
 // Forward defined as
-// template <typename T, class P = FreeStoreAllocationPolicy> class List;
-template <typename T, class P>
-class List {
+// template <typename T, class Allocator = FreeStoreAllocator> class List;
+//
+// Implementation note: List privately inherits from Allocator to
+// allow empty base class optimization.
+template <typename T, class Allocator>
+class List : private Allocator {
  public:
-
-  List() { Initialize(0); }
-  INLINE(explicit List(int capacity)) { Initialize(capacity); }
+  explicit List(const Allocator& allocator = Allocator())
+      : Allocator(allocator) { Initialize(0); }
+  INLINE(explicit List(int capacity, const Allocator& allocator = Allocator()))
+      : Allocator(allocator) {
+    Initialize(capacity);
+  }
   INLINE(~List()) { DeleteData(data_); }
 
   // Deallocates memory used by the list and leaves the list in a consistent
   // empty state.
   void Free() {
     DeleteData(data_);
     Initialize(0);
   }
 
   INLINE(void* operator new(size_t size)) {
-      return P::New(static_cast<int>(size));
+    return Allocator().New(static_cast<int>(size));
   }
-  INLINE(void operator delete(void* p, size_t)) { return P::Delete(p); }
+  INLINE(void operator delete(void* p, size_t)) {
+    return Allocator().Delete(p);
+  }
 
   // Returns a reference to the element at index i.  This reference is
   // not safe to use after operations that can change the list's
   // backing store (eg, Add).
   inline T& operator[](int i) const {
     ASSERT(0 <= i);
     ASSERT(i < length_);
     return data_[i];
   }
   inline T& at(int i) const { return operator[](i); }
   inline T& last() const { return at(length_ - 1); }
   inline T& first() const { return at(0); }
 
   INLINE(bool is_empty() const) { return length_ == 0; }
   INLINE(int length() const) { return length_; }
   INLINE(int capacity() const) { return capacity_; }
 
   Vector<T> ToVector() const { return Vector<T>(data_, length_); }
 
   Vector<const T> ToConstVector() { return Vector<const T>(data_, length_); }
 
   // Adds a copy of the given 'element' to the end of the list,
   // expanding the list if necessary.
   void Add(const T& element);
 
   // Add all the elements from the argument list to this list.
-  void AddAll(const List<T, P>& other);
+  void AddAll(const List<T, Allocator>& other);
 
   // Add all the elements from the vector to this list.
   void AddAll(const Vector<T>& other);
 
   // Inserts the element at the specific index.
   void InsertAt(int index, const T& element);
 
   // Added 'count' elements with the value 'value' and returns a
   // vector that allows access to the elements.  The vector is valid
   // until the next change is made to this list.
@@ skipping 35 matching lines @@
   void Sort(int (*cmp)(const T* x, const T* y));
   void Sort();
 
   INLINE(void Initialize(int capacity));
 
  private:
   T* data_;
   int capacity_;
   int length_;
 
-  INLINE(T* NewData(int n))  { return static_cast<T*>(P::New(n * sizeof(T))); }
-  INLINE(void DeleteData(T* data))  { P::Delete(data); }
+  INLINE(T* NewData(int n))  {
+    return static_cast<T*>(this->Allocator::New(n * sizeof(T)));
+  }
+  INLINE(void DeleteData(T* data)) { this->Allocator::Delete(data); }
 
   // Increase the capacity of a full list, and add an element.
   // List must be full already.
   void ResizeAdd(const T& element);
 
   // Inlined implementation of ResizeAdd, shared by inlined and
   // non-inlined versions of ResizeAdd.
   void ResizeAddInternal(const T& element);
 
   // Resize the list.
   void Resize(int new_capacity);
 
   DISALLOW_COPY_AND_ASSIGN(List);
 };
 
 class Map;
 class Code;
 typedef List<Map*> MapList;
 typedef List<Code*> CodeList;
 
 } }  // namespace v8::internal
 
 #endif  // V8_LIST_H_