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      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 
     17 namespace mcld {
     18 // FIXME: llvm::ELF doesn't define AArch64 dynamic relocation types
     19 enum {
     20   // static relocations
     21   R_AARCH64_ADR_PREL_PG_HI21_NC = 0x114,
     22   // dyanmic rlocations
     23   R_AARCH64_COPY                = 1024,
     24   R_AARCH64_GLOB_DAT            = 1025,
     25   R_AARCH64_JUMP_SLOT           = 1026,
     26   R_AARCH64_RELATIVE            = 1027,
     27   R_AARCH64_TLS_DTPREL64        = 1028,
     28   R_AARCH64_TLS_DTPMOD64        = 1029,
     29   R_AARCH64_TLS_TPREL64         = 1030,
     30   R_AARCH64_TLSDESC             = 1031,
     31   R_AARCH64_IRELATIVE           = 1032
     32 };
     33 
     34 /** \class AArch64Relocator
     35  *  \brief AArch64Relocator creates and destroys the AArch64 relocations.
     36  *
     37  */
     38 class AArch64Relocator : public Relocator
     39 {
     40 public:
     41   typedef KeyEntryMap<ResolveInfo, AArch64GOTEntry> SymGOTMap;
     42   typedef KeyEntryMap<ResolveInfo, AArch64PLT1> SymPLTMap;
     43   typedef KeyEntryMap<Relocation, Relocation> RelRelMap;
     44 
     45   /** \enum ReservedEntryType
     46    *  \brief The reserved entry type of reserved space in ResolveInfo.
     47    *
     48    *  This is used for sacnRelocation to record what kinds of entries are
     49    *  reserved for this resolved symbol In AArch64, there are three kinds of
     50    *  entries, GOT, PLT, and dynamic reloction.
     51    *
     52    *  bit:  3     2     1     0
     53    *   |    | PLT | GOT | Rel |
     54    *
     55    *  value    Name         - Description
     56    *
     57    *  0000     None         - no reserved entry
     58    *  0001     ReserveRel   - reserve an dynamic relocation entry
     59    *  0010     ReserveGOT   - reserve an GOT entry
     60    *  0100     ReservePLT   - reserve an PLT entry and the corresponding GOT,
     61    *
     62    */
     63   enum ReservedEntryType {
     64     None         = 0,
     65     ReserveRel   = 1,
     66     ReserveGOT   = 2,
     67     ReservePLT   = 4,
     68   };
     69 
     70   /** \enum EntryValue
     71    *  \brief The value of the entries. The symbol value will be decided at after
     72    *  layout, so we mark the entry during scanRelocation and fill up the actual
     73    *  value when applying relocations.
     74    */
     75   enum EntryValue {
     76     Default = 0,
     77     SymVal  = 1
     78   };
     79 
     80 public:
     81   AArch64Relocator(AArch64GNULDBackend& pParent, const LinkerConfig& pConfig);
     82   ~AArch64Relocator();
     83 
     84   Result applyRelocation(Relocation& pRelocation);
     85 
     86   AArch64GNULDBackend& getTarget()
     87   { return m_Target; }
     88 
     89   const AArch64GNULDBackend& getTarget() const
     90   { return m_Target; }
     91 
     92   const char* getName(Relocation::Type pType) const;
     93 
     94   Size getSize(Relocation::Type pType) const;
     95 
     96   const SymGOTMap& getSymGOTMap() const { return m_SymGOTMap; }
     97   SymGOTMap&       getSymGOTMap()       { return m_SymGOTMap; }
     98 
     99   const SymPLTMap& getSymPLTMap() const { return m_SymPLTMap; }
    100   SymPLTMap&       getSymPLTMap()       { return m_SymPLTMap; }
    101 
    102   const SymGOTMap& getSymGOTPLTMap() const { return m_SymGOTPLTMap; }
    103   SymGOTMap&       getSymGOTPLTMap()       { return m_SymGOTPLTMap; }
    104 
    105   const RelRelMap& getRelRelMap() const { return m_RelRelMap; }
    106   RelRelMap&       getRelRelMap()       { return m_RelRelMap; }
    107 
    108   /// scanRelocation - determine the empty entries are needed or not and create
    109   /// the empty entries if needed.
    110   /// For AArch64, following entries are check to create:
    111   /// - GOT entry (for .got section)
    112   /// - PLT entry (for .plt section)
    113   /// - dynamin relocation entries (for .rel.plt and .rel.dyn sections)
    114   void scanRelocation(Relocation& pReloc,
    115                       IRBuilder& pBuilder,
    116                       Module& pModule,
    117                       LDSection& pSection,
    118                       Input& pInput);
    119 
    120 private:
    121   void scanLocalReloc(Relocation& pReloc, const LDSection& pSection);
    122 
    123   void scanGlobalReloc(Relocation& pReloc,
    124                        IRBuilder& pBuilder,
    125                        const LDSection& pSection);
    126 
    127   /// addCopyReloc - add a copy relocation into .rel.dyn for pSym
    128   /// @param pSym - A resolved copy symbol that defined in BSS section
    129   void addCopyReloc(ResolveInfo& pSym);
    130 
    131   /// defineSymbolforCopyReloc - allocate a space in BSS section and
    132   /// and force define the copy of pSym to BSS section
    133   /// @return the output LDSymbol of the copy symbol
    134   LDSymbol& defineSymbolforCopyReloc(IRBuilder& pLinker,
    135                                      const ResolveInfo& pSym);
    136 
    137 private:
    138   AArch64GNULDBackend& m_Target;
    139   SymGOTMap m_SymGOTMap;
    140   SymPLTMap m_SymPLTMap;
    141   SymGOTMap m_SymGOTPLTMap;
    142   RelRelMap m_RelRelMap;
    143 };
    144 
    145 } // namespace of mcld
    146 
    147 #endif
    148 
    149