AArch64Relocator.h revision cfcb22478ca64c308df58f9abe6fa2dedb213c16 
1//===-  AArch64Relocator.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 TARGET_AARCH64_AARCH64RELOCATOR_H_
10#define TARGET_AARCH64_AARCH64RELOCATOR_H_
11
12#include "mcld/LD/Relocator.h"
13#include "mcld/Target/GOT.h"
14#include "mcld/Target/KeyEntryMap.h"
15#include "AArch64LDBackend.h"
16
17namespace mcld {
18
19/** \class AArch64Relocator
20 *  \brief AArch64Relocator creates and destroys the AArch64 relocations.
21 *
22 */
23class AArch64Relocator : public Relocator {
24 public:
25  typedef KeyEntryMap<ResolveInfo, AArch64GOTEntry> SymGOTMap;
26  typedef KeyEntryMap<ResolveInfo, AArch64PLT1> SymPLTMap;
27  typedef KeyEntryMap<Relocation, Relocation> RelRelMap;
28
29  /** \enum ReservedEntryType
30   *  \brief The reserved entry type of reserved space in ResolveInfo.
31   *
32   *  This is used for sacnRelocation to record what kinds of entries are
33   *  reserved for this resolved symbol In AArch64, there are three kinds of
34   *  entries, GOT, PLT, and dynamic reloction.
35   *
36   *  bit:  3     2     1     0
37   *   |    | PLT | GOT | Rel |
38   *
39   *  value    Name         - Description
40   *
41   *  0000     None         - no reserved entry
42   *  0001     ReserveRel   - reserve an dynamic relocation entry
43   *  0010     ReserveGOT   - reserve an GOT entry
44   *  0100     ReservePLT   - reserve an PLT entry and the corresponding GOT,
45   *
46   */
47  enum ReservedEntryType {
48    None = 0,
49    ReserveRel = 1,
50    ReserveGOT = 2,
51    ReservePLT = 4,
52  };
53
54  /** \enum EntryValue
55   *  \brief The value of the entries. The symbol value will be decided at after
56   *  layout, so we mark the entry during scanRelocation and fill up the actual
57   *  value when applying relocations.
58   */
59  enum EntryValue { Default = 0, SymVal = 1 };
60
61  enum {
62    // mcld internal relocation to rewrite an instruction.
63    R_AARCH64_REWRITE_INSN = 1,
64  };
65
66 public:
67  AArch64Relocator(AArch64GNULDBackend& pParent, const LinkerConfig& pConfig);
68  ~AArch64Relocator();
69
70  Result applyRelocation(Relocation& pRelocation);
71
72  AArch64GNULDBackend& getTarget() { return m_Target; }
73
74  const AArch64GNULDBackend& getTarget() const { return m_Target; }
75
76  const char* getName(Relocation::Type pType) const;
77
78  Size getSize(Relocation::Type pType) const;
79
80  const SymGOTMap& getSymGOTMap() const { return m_SymGOTMap; }
81  SymGOTMap& getSymGOTMap() { return m_SymGOTMap; }
82
83  const SymPLTMap& getSymPLTMap() const { return m_SymPLTMap; }
84  SymPLTMap& getSymPLTMap() { return m_SymPLTMap; }
85
86  const SymGOTMap& getSymGOTPLTMap() const { return m_SymGOTPLTMap; }
87  SymGOTMap& getSymGOTPLTMap() { return m_SymGOTPLTMap; }
88
89  const RelRelMap& getRelRelMap() const { return m_RelRelMap; }
90  RelRelMap& getRelRelMap() { return m_RelRelMap; }
91
92  /// scanRelocation - determine the empty entries are needed or not and create
93  /// the empty entries if needed.
94  /// For AArch64, following entries are check to create:
95  /// - GOT entry (for .got section)
96  /// - PLT entry (for .plt section)
97  /// - dynamin relocation entries (for .rel.plt and .rel.dyn sections)
98  void scanRelocation(Relocation& pReloc,
99                      IRBuilder& pBuilder,
100                      Module& pModule,
101                      LDSection& pSection,
102                      Input& pInput);
103
104  /// mayHaveFunctionPointerAccess - check if the given reloc would possibly
105  /// access a function pointer.
106  virtual bool mayHaveFunctionPointerAccess(const Relocation& pReloc) const;
107
108  /// getDebugStringOffset - get the offset from the relocation target. This is
109  /// used to get the debug string offset.
110  uint32_t getDebugStringOffset(Relocation& pReloc) const;
111
112  /// applyDebugStringOffset - apply the relocation target to specific offset.
113  /// This is used to set the debug string offset.
114  void applyDebugStringOffset(Relocation& pReloc, uint32_t pOffset);
115
116 private:
117  void scanLocalReloc(Relocation& pReloc, const LDSection& pSection);
118
119  void scanGlobalReloc(Relocation& pReloc,
120                       IRBuilder& pBuilder,
121                       const LDSection& pSection);
122
123  /// addCopyReloc - add a copy relocation into .rel.dyn for pSym
124  /// @param pSym - A resolved copy symbol that defined in BSS section
125  void addCopyReloc(ResolveInfo& pSym);
126
127  /// defineSymbolforCopyReloc - allocate a space in BSS section and
128  /// and force define the copy of pSym to BSS section
129  /// @return the output LDSymbol of the copy symbol
130  LDSymbol& defineSymbolforCopyReloc(IRBuilder& pLinker,
131                                     const ResolveInfo& pSym);
132
133 private:
134  AArch64GNULDBackend& m_Target;
135  SymGOTMap m_SymGOTMap;
136  SymPLTMap m_SymPLTMap;
137  SymGOTMap m_SymGOTPLTMap;
138  RelRelMap m_RelRelMap;
139};
140
141}  // namespace mcld
142
143#endif  // TARGET_AARCH64_AARCH64RELOCATOR_H_
144