Make the DenseMap bucket type configurable and use a smaller bucket for DenseSet.

[oota-llvm.git] / include / llvm / ADT / ilist_node.h

diff --git a/include/llvm/ADT/ilist_node.h b/include/llvm/ADT/ilist_node.h
index 9e6031170664001fb15b4ada1f72820b7b08b417..26d0b55e4093e3b34c6e1d63265f71eeb6382044 100644 (file)
--- a/include/llvm/ADT/ilist_node.h
+++ b/include/llvm/ADT/ilist_node.h
@@ -1,10 +1,10 @@
 //==-- llvm/ADT/ilist_node.h - Intrusive Linked List Helper ------*- C++ -*-==//
-// 
+//
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
-// 
+//
 //===----------------------------------------------------------------------===//
 //
 // This file defines the ilist_node class template, which is a convenient
@@ -17,6 +17,22 @@
 
 namespace llvm {
 
+template<typename NodeTy>
+struct ilist_traits;
+
+/// ilist_half_node - Base class that provides prev services for sentinels.
+///
+template<typename NodeTy>
+class ilist_half_node {
+  friend struct ilist_traits<NodeTy>;
+  NodeTy *Prev;
+protected:
+  NodeTy *getPrev() { return Prev; }
+  const NodeTy *getPrev() const { return Prev; }
+  void setPrev(NodeTy *P) { Prev = P; }
+  ilist_half_node() : Prev(nullptr) {}
+};
+
 template<typename NodeTy>
 struct ilist_nextprev_traits;
 
@@ -24,18 +40,65 @@ struct ilist_nextprev_traits;
 /// that use ilist_nextprev_traits or ilist_default_traits.
 ///
 template<typename NodeTy>
-class ilist_node {
-private:
+class ilist_node : private ilist_half_node<NodeTy> {
   friend struct ilist_nextprev_traits<NodeTy>;
-  NodeTy *Prev, *Next;
-  NodeTy *getPrev() { return Prev; }
+  friend struct ilist_traits<NodeTy>;
+  NodeTy *Next;
   NodeTy *getNext() { return Next; }
-  const NodeTy *getPrev() const { return Prev; }
   const NodeTy *getNext() const { return Next; }
-  void setPrev(NodeTy *N) { Prev = N; }
   void setNext(NodeTy *N) { Next = N; }
 protected:
-  ilist_node() : Prev(0), Next(0) {}
+  ilist_node() : Next(nullptr) {}
+
+public:
+  /// @name Adjacent Node Accessors
+  /// @{
+
+  /// \brief Get the previous node, or 0 for the list head.
+  NodeTy *getPrevNode() {
+    NodeTy *Prev = this->getPrev();
+
+    // Check for sentinel.
+    if (!Prev->getNext())
+      return nullptr;
+
+    return Prev;
+  }
+
+  /// \brief Get the previous node, or 0 for the list head.
+  const NodeTy *getPrevNode() const {
+    const NodeTy *Prev = this->getPrev();
+
+    // Check for sentinel.
+    if (!Prev->getNext())
+      return nullptr;
+
+    return Prev;
+  }
+
+  /// \brief Get the next node, or 0 for the list tail.
+  NodeTy *getNextNode() {
+    NodeTy *Next = getNext();
+
+    // Check for sentinel.
+    if (!Next->getNext())
+      return nullptr;
+
+    return Next;
+  }
+
+  /// \brief Get the next node, or 0 for the list tail.
+  const NodeTy *getNextNode() const {
+    const NodeTy *Next = getNext();
+
+    // Check for sentinel.
+    if (!Next->getNext())
+      return nullptr;
+
+    return Next;
+  }
+
+  /// @}
 };
 
 } // End llvm namespace