ARMRelocator.h revision f7ac0f19a1c8d0ad14bcf6456ce368b830fea886 
1//===-  ARMRelocator.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 ARM_RELOCATION_FACTORY_H
10#define ARM_RELOCATION_FACTORY_H
11#ifdef ENABLE_UNITTEST
12#include <gtest.h>
13#endif
14
15#include <mcld/LD/Relocator.h>
16#include <mcld/Target/GOT.h>
17#include <mcld/Target/SymbolEntryMap.h>
18#include "ARMLDBackend.h"
19
20namespace mcld {
21
22/** \class ARMRelocator
23 *  \brief ARMRelocator creates and destroys the ARM relocations.
24 *
25 */
26class ARMRelocator : public Relocator
27{
28public:
29  typedef SymbolEntryMap<ARMGOTEntry> SymGOTMap;
30  typedef SymbolEntryMap<ARMPLT1> SymPLTMap;
31
32  /** \enum ReservedEntryType
33   *  \brief The reserved entry type of reserved space in ResolveInfo.
34   *
35   *  This is used for sacnRelocation to record what kinds of entries are
36   *  reserved for this resolved symbol
37   *
38   *  In ARM, there are three kinds of entries, GOT, PLT, and dynamic reloction.
39   *  GOT may needs a corresponding relocation to relocate itself, so we
40   *  separate GOT to two situations: GOT and GOTRel. Besides, for the same
41   *  symbol, there might be two kinds of entries reserved for different location.
42   *  For example, reference to the same symbol, one may use GOT and the other may
43   *  use dynamic relocation.
44   *
45   *  bit:  3       2      1     0
46   *   | PLT | GOTRel | GOT | Rel |
47   *
48   *  value    Name         - Description
49   *
50   *  0000     None         - no reserved entry
51   *  0001     ReserveRel   - reserve an dynamic relocation entry
52   *  0010     ReserveGOT   - reserve an GOT entry
53   *  0011     GOTandRel    - For different relocation, we've reserved GOT and
54   *                          Rel for different location.
55   *  0100     GOTRel       - reserve an GOT entry and the corresponding Dyncamic
56   *                          relocation entry which relocate this GOT entry
57   *  0101     GOTRelandRel - For different relocation, we've reserved GOTRel
58   *                          and relocation entry for different location.
59   *  1000     ReservePLT   - reserve an PLT entry and the corresponding GOT,
60   *                          Dynamic relocation entries
61   *  1001     PLTandRel    - For different relocation, we've reserved PLT and
62   *                          Rel for different location.
63   */
64  enum ReservedEntryType {
65    None         = 0,
66    ReserveRel   = 1,
67    ReserveGOT   = 2,
68    GOTandRel    = 3,
69    GOTRel       = 4,
70    GOTRelandRel = 5,
71    ReservePLT   = 8,
72    PLTandRel    = 9
73  };
74
75public:
76  ARMRelocator(ARMGNULDBackend& pParent, const LinkerConfig& pConfig);
77  ~ARMRelocator();
78
79  Result applyRelocation(Relocation& pRelocation);
80
81  ARMGNULDBackend& getTarget()
82  { return m_Target; }
83
84  const ARMGNULDBackend& getTarget() const
85  { return m_Target; }
86
87  const char* getName(Relocation::Type pType) const;
88
89  Size getSize(Relocation::Type pType) const;
90
91  const SymGOTMap& getSymGOTMap() const { return m_SymGOTMap; }
92  SymGOTMap&       getSymGOTMap()       { return m_SymGOTMap; }
93
94  const SymPLTMap& getSymPLTMap() const { return m_SymPLTMap; }
95  SymPLTMap&       getSymPLTMap()       { return m_SymPLTMap; }
96
97  const SymGOTMap& getSymGOTPLTMap() const { return m_SymGOTPLTMap; }
98  SymGOTMap&       getSymGOTPLTMap()       { return m_SymGOTPLTMap; }
99
100  /// scanRelocation - determine the empty entries are needed or not and create
101  /// the empty entries if needed.
102  /// For ARM, following entries are check to create:
103  /// - GOT entry (for .got section)
104  /// - PLT entry (for .plt section)
105  /// - dynamin relocation entries (for .rel.plt and .rel.dyn sections)
106  void scanRelocation(Relocation& pReloc,
107                      IRBuilder& pBuilder,
108                      Module& pModule,
109                      LDSection& pSection);
110
111private:
112  void scanLocalReloc(Relocation& pReloc, const LDSection& pSection);
113
114  void scanGlobalReloc(Relocation& pReloc,
115                       IRBuilder& pBuilder,
116                       const LDSection& pSection);
117
118  void checkValidReloc(Relocation& pReloc) const;
119
120  /// addCopyReloc - add a copy relocation into .rel.dyn for pSym
121  /// @param pSym - A resolved copy symbol that defined in BSS section
122  void addCopyReloc(ResolveInfo& pSym);
123
124  /// defineSymbolforCopyReloc - allocate a space in BSS section and
125  /// and force define the copy of pSym to BSS section
126  /// @return the output LDSymbol of the copy symbol
127  LDSymbol& defineSymbolforCopyReloc(IRBuilder& pLinker,
128                                     const ResolveInfo& pSym);
129
130private:
131  ARMGNULDBackend& m_Target;
132  SymGOTMap m_SymGOTMap;
133  SymPLTMap m_SymPLTMap;
134  SymGOTMap m_SymGOTPLTMap;
135};
136
137} // namespace of mcld
138
139#endif
140
141