AArch64LDBackend.h revision 0dea6bc96bb52346737966839ac68644f7939f58 
1//===- AArch64LDBackend.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_AARCH64LDBACKEND_H
10#define TARGET_AARCH64_AARCH64LDBACKEND_H
11
12#include "AArch64ELFDynamic.h"
13#include "AArch64GOT.h"
14#include "AArch64PLT.h"
15#include <mcld/LD/LDSection.h>
16#include <mcld/Target/GNULDBackend.h>
17#include <mcld/Target/OutputRelocSection.h>
18
19namespace mcld {
20
21class LinkerConfig;
22class GNUInfo;
23
24//===----------------------------------------------------------------------===//
25/// AArch64GNULDBackend - linker backend of AArch64 target of GNU ELF format
26///
27class AArch64GNULDBackend : public GNULDBackend
28{
29public:
30  static const int64_t AARCH64_MAX_FWD_BRANCH_OFFSET = (((1 << 25) - 1) << 2);
31  static const int64_t AARCH64_MAX_BWD_BRANCH_OFFSET = (-((1 << 25) << 2));
32
33public:
34  AArch64GNULDBackend(const LinkerConfig& pConfig, GNUInfo* pInfo);
35  ~AArch64GNULDBackend();
36
37public:
38  /// initTargetSections - initialize target dependent sections in output.
39  void initTargetSections(Module& pModule, ObjectBuilder& pBuilder);
40
41  /// initTargetSymbols - initialize target dependent symbols in output.
42  void initTargetSymbols(IRBuilder& pBuilder, Module& pModule);
43
44  /// initRelocator - create and initialize Relocator.
45  bool initRelocator();
46
47  /// getRelocator - return relocator.
48  const Relocator* getRelocator() const;
49  Relocator* getRelocator();
50
51  /// doPreLayout - Backend can do any needed modification before layout
52  void doPreLayout(IRBuilder& pBuilder);
53
54  /// doPostLayout -Backend can do any needed modification after layout
55  void doPostLayout(Module& pModule, IRBuilder& pBuilder);
56
57  /// dynamic - the dynamic section of the target machine.
58  /// Use co-variant return type to return its own dynamic section.
59  AArch64ELFDynamic& dynamic();
60
61  /// dynamic - the dynamic section of the target machine.
62  /// Use co-variant return type to return its own dynamic section.
63  const AArch64ELFDynamic& dynamic() const;
64
65
66  /// emitSectionData - write out the section data into the memory region.
67  /// When writers get a LDSection whose kind is LDFileFormat::Target, writers
68  /// call back target backend to emit the data.
69  ///
70  /// Backends handle the target-special tables (plt, gp,...) by themselves.
71  /// Backend can put the data of the tables in SectionData directly
72  ///  - LDSection.getSectionData can get the section data.
73  /// Or, backend can put the data into special data structure
74  ///  - backend can maintain its own map<LDSection, table> to get the table
75  /// from given LDSection.
76  ///
77  /// @param pSection - the given LDSection
78  /// @param pConfig - all options in the command line.
79  /// @param pRegion - the region to write out data
80  /// @return the size of the table in the file.
81  uint64_t emitSectionData(const LDSection& pSection,
82                           MemoryRegion& pRegion) const;
83
84  AArch64GOT& getGOT();
85  const AArch64GOT& getGOT() const;
86
87  AArch64GOT& getGOTPLT();
88  const AArch64GOT& getGOTPLT() const;
89
90  AArch64PLT& getPLT();
91  const AArch64PLT& getPLT() const;
92
93  OutputRelocSection& getRelaDyn();
94  const OutputRelocSection& getRelaDyn() const;
95
96  OutputRelocSection& getRelaPLT();
97  const OutputRelocSection& getRelaPLT() const;
98
99  LDSymbol* getGOTSymbol()             { return m_pGOTSymbol; }
100  const LDSymbol* getGOTSymbol() const { return m_pGOTSymbol; }
101
102  /// getTargetSectionOrder - compute the layout order of AArch64 target sections
103  unsigned int getTargetSectionOrder(const LDSection& pSectHdr) const;
104
105  /// finalizeTargetSymbols - finalize the symbol value
106  bool finalizeTargetSymbols();
107
108  /// mergeSection - merge target dependent sections
109  bool mergeSection(Module& pModule, const Input& pInput, LDSection& pSection);
110
111  /// readSection - read target dependent sections
112  bool readSection(Input& pInput, SectionData& pSD);
113
114private:
115  void defineGOTSymbol(IRBuilder& pBuilder);
116
117  int64_t maxFwdBranchOffset() { return AARCH64_MAX_FWD_BRANCH_OFFSET; }
118  int64_t maxBwdBranchOffset() { return AARCH64_MAX_BWD_BRANCH_OFFSET; }
119
120  /// mayRelax - Backends should override this function if they need relaxation
121  bool mayRelax() { return true; }
122
123  /// doRelax - Backend can orevride this function to add its relaxation
124  /// implementation. Return true if the output (e.g., .text) is "relaxed"
125  /// (i.e. layout is changed), and set pFinished to true if everything is fit,
126  /// otherwise set it to false.
127  bool doRelax(Module& pModule, IRBuilder& pBuilder, bool& pFinished);
128
129  /// initTargetStubs
130  bool initTargetStubs();
131
132  /// getRelEntrySize - the size in BYTE of rel type relocation
133  size_t getRelEntrySize()
134  { return 16; }
135
136  /// getRelEntrySize - the size in BYTE of rela type relocation
137  size_t getRelaEntrySize()
138  { return 24; }
139
140  /// doCreateProgramHdrs - backend can implement this function to create the
141  /// target-dependent segments
142  virtual void doCreateProgramHdrs(Module& pModule);
143
144private:
145  Relocator* m_pRelocator;
146
147  AArch64GOT* m_pGOT;
148  AArch64GOT* m_pGOTPLT;
149  AArch64PLT* m_pPLT;
150  /// m_RelDyn - dynamic relocation table of .rel.dyn
151  OutputRelocSection* m_pRelaDyn;
152  /// m_RelPLT - dynamic relocation table of .rel.plt
153  OutputRelocSection* m_pRelaPLT;
154
155  /// m_pAttrData - attribute data in public ("aeabi") attribute subsection
156  // AArch64ELFAttributeData* m_pAttrData;
157
158  AArch64ELFDynamic* m_pDynamic;
159  LDSymbol* m_pGOTSymbol;
160
161  //     variable name           :  ELF
162  // LDSection* m_pAttributes;      // .ARM.attributes
163  // LDSection* m_pPreemptMap;      // .AArch64.preemptmap
164  // LDSection* m_pDebugOverlay;    // .AArch64.debug_overlay
165  // LDSection* m_pOverlayTable;    // .AArch64.overlay_table
166};
167} // namespace of mcld
168
169#endif
170
171