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 19 namespace mcld { 20 21 class LinkerConfig; 22 class GNUInfo; 23 24 //===----------------------------------------------------------------------===// 25 /// AArch64GNULDBackend - linker backend of AArch64 target of GNU ELF format 26 /// 27 class AArch64GNULDBackend : public GNULDBackend { 28 public: 29 static const int64_t AARCH64_MAX_FWD_BRANCH_OFFSET = (((1 << 25) - 1) << 2); 30 static const int64_t AARCH64_MAX_BWD_BRANCH_OFFSET = (-((1 << 25) << 2)); 31 32 public: 33 AArch64GNULDBackend(const LinkerConfig& pConfig, GNUInfo* pInfo); 34 ~AArch64GNULDBackend(); 35 36 public: 37 /// initTargetSections - initialize target dependent sections in output. 38 void initTargetSections(Module& pModule, ObjectBuilder& pBuilder); 39 40 /// initTargetSymbols - initialize target dependent symbols in output. 41 void initTargetSymbols(IRBuilder& pBuilder, Module& pModule); 42 43 /// initRelocator - create and initialize Relocator. 44 bool initRelocator(); 45 46 /// getRelocator - return relocator. 47 const Relocator* getRelocator() const; 48 Relocator* getRelocator(); 49 50 /// doPreLayout - Backend can do any needed modification before layout 51 void doPreLayout(IRBuilder& pBuilder); 52 53 /// doPostLayout -Backend can do any needed modification after layout 54 void doPostLayout(Module& pModule, IRBuilder& pBuilder); 55 56 /// dynamic - the dynamic section of the target machine. 57 /// Use co-variant return type to return its own dynamic section. 58 AArch64ELFDynamic& dynamic(); 59 60 /// dynamic - the dynamic section of the target machine. 61 /// Use co-variant return type to return its own dynamic section. 62 const AArch64ELFDynamic& dynamic() const; 63 64 /// emitSectionData - write out the section data into the memory region. 65 /// When writers get a LDSection whose kind is LDFileFormat::Target, writers 66 /// call back target backend to emit the data. 67 /// 68 /// Backends handle the target-special tables (plt, gp,...) by themselves. 69 /// Backend can put the data of the tables in SectionData directly 70 /// - LDSection.getSectionData can get the section data. 71 /// Or, backend can put the data into special data structure 72 /// - backend can maintain its own map<LDSection, table> to get the table 73 /// from given LDSection. 74 /// 75 /// @param pSection - the given LDSection 76 /// @param pConfig - all options in the command line. 77 /// @param pRegion - the region to write out data 78 /// @return the size of the table in the file. 79 uint64_t emitSectionData(const LDSection& pSection, 80 MemoryRegion& pRegion) const; 81 82 AArch64GOT& getGOT(); 83 const AArch64GOT& getGOT() const; 84 85 AArch64GOT& getGOTPLT(); 86 const AArch64GOT& getGOTPLT() const; 87 88 AArch64PLT& getPLT(); 89 const AArch64PLT& getPLT() const; 90 91 OutputRelocSection& getRelaDyn(); 92 const OutputRelocSection& getRelaDyn() const; 93 94 OutputRelocSection& getRelaPLT(); 95 const OutputRelocSection& getRelaPLT() const; 96 getGOTSymbol()97 LDSymbol* getGOTSymbol() { return m_pGOTSymbol; } getGOTSymbol()98 const LDSymbol* getGOTSymbol() const { return m_pGOTSymbol; } 99 100 /// getTargetSectionOrder - compute the layout order of AArch64 target 101 /// sections 102 unsigned int getTargetSectionOrder(const LDSection& pSectHdr) const; 103 104 /// finalizeTargetSymbols - finalize the symbol value 105 bool finalizeTargetSymbols(); 106 107 /// mergeSection - merge target dependent sections 108 bool mergeSection(Module& pModule, const Input& pInput, LDSection& pSection); 109 110 /// readSection - read target dependent sections 111 bool readSection(Input& pInput, SectionData& pSD); 112 113 private: 114 void defineGOTSymbol(IRBuilder& pBuilder); 115 maxFwdBranchOffset()116 int64_t maxFwdBranchOffset() { return AARCH64_MAX_FWD_BRANCH_OFFSET; } maxBwdBranchOffset()117 int64_t maxBwdBranchOffset() { return AARCH64_MAX_BWD_BRANCH_OFFSET; } 118 119 /// mayRelax - Backends should override this function if they need relaxation mayRelax()120 bool mayRelax() { return true; } 121 122 /// doRelax - Backend can orevride this function to add its relaxation 123 /// implementation. Return true if the output (e.g., .text) is "relaxed" 124 /// (i.e. layout is changed), and set pFinished to true if everything is fit, 125 /// otherwise set it to false. 126 bool doRelax(Module& pModule, IRBuilder& pBuilder, bool& pFinished); 127 128 /// initTargetStubs 129 bool initTargetStubs(); 130 131 /// getRelEntrySize - the size in BYTE of rel type relocation getRelEntrySize()132 size_t getRelEntrySize() { return 16; } 133 134 /// getRelEntrySize - the size in BYTE of rela type relocation getRelaEntrySize()135 size_t getRelaEntrySize() { return 24; } 136 137 /// doCreateProgramHdrs - backend can implement this function to create the 138 /// target-dependent segments 139 virtual void doCreateProgramHdrs(Module& pModule); 140 141 private: 142 Relocator* m_pRelocator; 143 144 AArch64GOT* m_pGOT; 145 AArch64GOT* m_pGOTPLT; 146 AArch64PLT* m_pPLT; 147 /// m_RelDyn - dynamic relocation table of .rel.dyn 148 OutputRelocSection* m_pRelaDyn; 149 /// m_RelPLT - dynamic relocation table of .rel.plt 150 OutputRelocSection* m_pRelaPLT; 151 152 /// m_pAttrData - attribute data in public ("aeabi") attribute subsection 153 // AArch64ELFAttributeData* m_pAttrData; 154 155 AArch64ELFDynamic* m_pDynamic; 156 LDSymbol* m_pGOTSymbol; 157 158 // variable name : ELF 159 // LDSection* m_pAttributes; // .ARM.attributes 160 // LDSection* m_pPreemptMap; // .AArch64.preemptmap 161 // LDSection* m_pDebugOverlay; // .AArch64.debug_overlay 162 // LDSection* m_pOverlayTable; // .AArch64.overlay_table 163 }; 164 165 } // namespace mcld 166 167 #endif // TARGET_AARCH64_AARCH64LDBACKEND_H_ 168