GOT.h revision d0fbbb227051be16931a1aa9b4a7722ac039c698 
1//===- GOT.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_GLOBAL_OFFSET_TABLE_H
10#define MCLD_GLOBAL_OFFSET_TABLE_H
11#ifdef ENABLE_UNITTEST
12#include <gtest.h>
13#endif
14
15#include <mcld/LD/LDSection.h>
16#include <mcld/LD/SectionData.h>
17#include <mcld/Fragment/TargetFragment.h>
18
19namespace mcld {
20
21class GOT;
22class LDSection;
23class ResolveInfo;
24
25/** \class GOT
26 *  \brief The Global Offset Table
27 */
28class GOT
29{
30protected:
31  GOT(LDSection& pSection);
32
33public:
34  typedef SectionData::iterator iterator;
35  typedef SectionData::const_iterator const_iterator;
36
37  template<size_t SIZE>
38  class Entry : public TargetFragment
39  {
40  public:
41    enum { EntrySize = SIZE };
42
43  public:
44    Entry(uint64_t pValue, SectionData* pParent)
45      : TargetFragment(Fragment::Target, pParent),
46        f_Value(pValue) {
47    }
48
49    virtual ~Entry() {}
50
51    uint64_t getValue() const
52    { return f_Value; }
53
54    void setValue(uint64_t pValue)
55    { f_Value = pValue; }
56
57    // Override pure virtual function
58    size_t size() const
59    { return EntrySize; }
60
61  protected:
62    uint64_t f_Value;
63  };
64
65public:
66  virtual ~GOT();
67
68  // ----- observers -----//
69  uint64_t addr() const { return m_Section.addr(); }
70
71  const_iterator begin() const { return m_SectionData->begin(); }
72  iterator       begin()       { return m_SectionData->begin(); }
73  const_iterator end  () const { return m_SectionData->end();   }
74  iterator       end  ()       { return m_SectionData->end();   }
75
76  bool empty() const
77  { return m_SectionData->empty(); }
78
79  // finalizeSectionSize - set LDSection size
80  virtual void finalizeSectionSize();
81
82  /// reserve - reseve number of pNum of empty entries
83  /// Before layout, we scan all relocations to determine if GOT entries are
84  /// needed. If an entry is needed, the empty entry is reserved for layout
85  /// to adjust the fragment offset. After that, we fill up the entries when
86  /// applying relocations.
87  virtual void reserve(size_t pNum = 1) = 0;
88
89protected:
90  LDSection& m_Section;
91  SectionData* m_SectionData;
92};
93
94} // namespace of mcld
95
96#endif
97
98