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 public:
29  static constexpr int64_t MAX_FWD_BRANCH_OFFSET = (((1 << 25) - 1) << 2);
30  static constexpr int64_t MAX_BWD_BRANCH_OFFSET = (-((1 << 25) << 2));
31
32  static constexpr int64_t MAX_ADRP_IMM = (1 << 20) - 1;
33  static constexpr int64_t MIN_ADRP_IMM = -(1 << 20);
34
35 public:
36  AArch64GNULDBackend(const LinkerConfig& pConfig, GNUInfo* pInfo);
37  ~AArch64GNULDBackend();
38
39 public:
40  /// initTargetSections - initialize target dependent sections in output.
41  void initTargetSections(Module& pModule, ObjectBuilder& pBuilder);
42
43  /// initTargetSymbols - initialize target dependent symbols in output.
44  void initTargetSymbols(IRBuilder& pBuilder, Module& pModule);
45
46  /// initRelocator - create and initialize Relocator.
47  bool initRelocator();
48
49  /// getRelocator - return relocator.
50  const Relocator* getRelocator() const;
51  Relocator* getRelocator();
52
53  /// doPreLayout - Backend can do any needed modification before layout
54  void doPreLayout(IRBuilder& pBuilder);
55
56  /// doPostLayout -Backend can do any needed modification after layout
57  void doPostLayout(Module& pModule, IRBuilder& pBuilder);
58
59  /// dynamic - the dynamic section of the target machine.
60  /// Use co-variant return type to return its own dynamic section.
61  AArch64ELFDynamic& dynamic();
62
63  /// dynamic - the dynamic section of the target machine.
64  /// Use co-variant return type to return its own dynamic section.
65  const AArch64ELFDynamic& dynamic() const;
66
67  /// emitSectionData - write out the section data into the memory region.
68  /// When writers get a LDSection whose kind is LDFileFormat::Target, writers
69  /// call back target backend to emit the data.
70  ///
71  /// Backends handle the target-special tables (plt, gp,...) by themselves.
72  /// Backend can put the data of the tables in SectionData directly
73  ///  - LDSection.getSectionData can get the section data.
74  /// Or, backend can put the data into special data structure
75  ///  - backend can maintain its own map<LDSection, table> to get the table
76  /// from given LDSection.
77  ///
78  /// @param pSection - the given LDSection
79  /// @param pConfig - all options in the command line.
80  /// @param pRegion - the region to write out data
81  /// @return the size of the table in the file.
82  uint64_t emitSectionData(const LDSection& pSection,
83                           MemoryRegion& pRegion) const;
84
85  AArch64GOT& getGOT();
86  const AArch64GOT& getGOT() const;
87
88  AArch64GOT& getGOTPLT();
89  const AArch64GOT& getGOTPLT() const;
90
91  AArch64PLT& getPLT();
92  const AArch64PLT& getPLT() const;
93
94  OutputRelocSection& getRelaDyn();
95  const OutputRelocSection& getRelaDyn() const;
96
97  OutputRelocSection& getRelaPLT();
98  const OutputRelocSection& getRelaPLT() const;
99
100  LDSymbol* getGOTSymbol() { return m_pGOTSymbol; }
101  const LDSymbol* getGOTSymbol() const { return m_pGOTSymbol; }
102
103  /// getTargetSectionOrder - compute the layout order of AArch64 target
104  /// sections
105  unsigned int getTargetSectionOrder(const LDSection& pSectHdr) const;
106
107  /// finalizeTargetSymbols - finalize the symbol value
108  bool finalizeTargetSymbols();
109
110  /// mergeSection - merge target dependent sections
111  bool mergeSection(Module& pModule, const Input& pInput, LDSection& pSection);
112
113  /// readSection - read target dependent sections
114  bool readSection(Input& pInput, SectionData& pSD);
115
116 private:
117  void defineGOTSymbol(IRBuilder& pBuilder);
118
119  int64_t maxFwdBranchOffset() const { return MAX_FWD_BRANCH_OFFSET; }
120  int64_t maxBwdBranchOffset() const { return MAX_BWD_BRANCH_OFFSET; }
121
122  void scanErrata(Module& pModule,
123                  IRBuilder& pBuilder,
124                  size_t& num_new_stubs,
125                  size_t& stubs_strlen);
126
127  /// mayRelax - Backends should override this function if they need relaxation
128  bool mayRelax() { return true; }
129
130  /// doRelax - Backend can orevride this function to add its relaxation
131  /// implementation. Return true if the output (e.g., .text) is "relaxed"
132  /// (i.e. layout is changed), and set pFinished to true if everything is fit,
133  /// otherwise set it to false.
134  bool doRelax(Module& pModule, IRBuilder& pBuilder, bool& pFinished);
135
136  /// initTargetStubs
137  bool initTargetStubs();
138
139  /// getRelEntrySize - the size in BYTE of rel type relocation
140  size_t getRelEntrySize() { return 16; }
141
142  /// getRelEntrySize - the size in BYTE of rela type relocation
143  size_t getRelaEntrySize() { return 24; }
144
145  /// doCreateProgramHdrs - backend can implement this function to create the
146  /// target-dependent segments
147  virtual void doCreateProgramHdrs(Module& pModule);
148
149 private:
150  Relocator* m_pRelocator;
151
152  AArch64GOT* m_pGOT;
153  AArch64GOT* m_pGOTPLT;
154  AArch64PLT* m_pPLT;
155  /// m_RelDyn - dynamic relocation table of .rel.dyn
156  OutputRelocSection* m_pRelaDyn;
157  /// m_RelPLT - dynamic relocation table of .rel.plt
158  OutputRelocSection* m_pRelaPLT;
159
160  /// m_pAttrData - attribute data in public ("aeabi") attribute subsection
161  // AArch64ELFAttributeData* m_pAttrData;
162
163  AArch64ELFDynamic* m_pDynamic;
164  LDSymbol* m_pGOTSymbol;
165
166  //     variable name           :  ELF
167  // LDSection* m_pAttributes;      // .ARM.attributes
168  // LDSection* m_pPreemptMap;      // .AArch64.preemptmap
169  // LDSection* m_pDebugOverlay;    // .AArch64.debug_overlay
170  // LDSection* m_pOverlayTable;    // .AArch64.overlay_table
171};
172
173}  // namespace mcld
174
175#endif  // TARGET_AARCH64_AARCH64LDBACKEND_H_
176