GCFactoryListTraits.h revision 37b74a387bb3993387029859c2d9d051c41c724e 
1//===- GCFactoryListTraits.h ----------------------------------------------===//
2//
3//                     The MCLinker Project
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9#ifndef MCLD_SUPPORT_GCFACTORYLISTTRAITS_H_
10#define MCLD_SUPPORT_GCFACTORYLISTTRAITS_H_
11
12#include <llvm/ADT/ilist.h>
13#include <llvm/ADT/ilist_node.h>
14
15#include <assert.h>
16
17namespace mcld {
18
19/** \class GCFactoryListTraits
20 *  \brief GCFactoryListTraits provides trait class for llvm::iplist when
21 *  the nodes in the list is produced by GCFactory.
22 */
23template <typename DataType>
24class GCFactoryListTraits : public llvm::ilist_default_traits<DataType> {
25 private:
26  class SentinelNode : public DataType {
27   public:
28    SentinelNode() {}
29  };
30
31 public:
32  // override the traits provided in llvm::ilist_sentinel_traits since we've
33  // defined our own sentinel.
34  DataType* createSentinel() const {
35    return reinterpret_cast<DataType*>(&mSentinel);
36  }
37
38  static void destroySentinel(DataType* pData) {}
39
40  DataType* provideInitialHead() const { return createSentinel(); }
41
42  DataType* ensureHead(DataType* pData) const { return createSentinel(); }
43
44  static void noteHead(DataType* pNew, DataType* pSentinel) {}
45
46  // override the traits provided in llvm::ilist_node_traits since
47  static DataType* createNode(const DataType& V) {
48    assert(false && "Only GCFactory knows how to create a node.");
49  }
50  static void deleteNode(DataType* V) {
51    // No action. GCFactory will handle it by itself.
52  }
53
54 private:
55  mutable SentinelNode mSentinel;
56};
57
58}  // namespace mcld
59
60#endif  // MCLD_SUPPORT_GCFACTORYLISTTRAITS_H_
61