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      1 //===-  HexagonRelocator.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_HEXAGON_HEXAGONRELOCATOR_H_
     10 #define TARGET_HEXAGON_HEXAGONRELOCATOR_H_
     11 
     12 #include "mcld/LD/Relocator.h"
     13 #include "mcld/Target/GOT.h"
     14 #include "mcld/Target/PLT.h"
     15 #include "mcld/Target/KeyEntryMap.h"
     16 #include "HexagonLDBackend.h"
     17 
     18 namespace mcld {
     19 
     20 class LinkerConfig;
     21 class ResolveInfo;
     22 
     23 /** \class HexagonRelocator
     24  *  \brief HexagonRelocator creates and destroys the Hexagon relocations.
     25  *
     26  */
     27 class HexagonRelocator : public Relocator {
     28  public:
     29   typedef KeyEntryMap<ResolveInfo, PLTEntryBase> SymPLTMap;
     30   typedef KeyEntryMap<ResolveInfo, HexagonGOTEntry> SymGOTMap;
     31   typedef KeyEntryMap<ResolveInfo, HexagonGOTEntry> SymGOTPLTMap;
     32   typedef KeyEntryMap<Relocation, Relocation> RelRelMap;
     33 
     34  public:
     35   /** \enum ReservedEntryType
     36    *  \brief The reserved entry type of reserved space in ResolveInfo.
     37    *
     38    *  This is used for sacnRelocation to record what kinds of entries are
     39    *  reserved for this resolved symbol. In Hexagon, there are three kinds
     40    *  of entries, GOT, PLT, and dynamic relocation.
     41    *
     42    *  bit:  3     2     1     0
     43    *   |    | PLT | GOT | Rel |
     44    *
     45    *  value    Name         - Description
     46    *
     47    *  0000     None         - no reserved entry
     48    *  0001     ReserveRel   - reserve an dynamic relocation entry
     49    *  0010     ReserveGOT   - reserve an GOT entry
     50    *  0100     ReservePLT   - reserve an PLT entry and the corresponding GOT,
     51    *
     52    */
     53   enum ReservedEntryType {
     54     None = 0,
     55     ReserveRel = 1,
     56     ReserveGOT = 2,
     57     ReservePLT = 4,
     58   };
     59 
     60   /** \enum EntryValue
     61    *  \brief The value of the entries. The symbol value will be decided at after
     62    *  layout, so we mark the entry during scanRelocation and fill up the actual
     63    *  value when applying relocations.
     64    */
     65   enum EntryValue { Default = 0, SymVal = 1 };
     66 
     67   HexagonRelocator(HexagonLDBackend& pParent, const LinkerConfig& pConfig);
     68   ~HexagonRelocator();
     69 
     70   Result applyRelocation(Relocation& pRelocation);
     71 
     72   /// scanRelocation - determine the empty entries are needed or not and create
     73   /// the empty entries if needed.
     74   /// For Hexagon, following entries are check to create:
     75   /// - GOT entry (for .got and .got.plt sections)
     76   /// - PLT entry (for .plt section)
     77   /// - dynamin relocation entries (for .rel.plt and .rel.dyn sections)
     78   void scanRelocation(Relocation& pReloc,
     79                       IRBuilder& pBuilder,
     80                       Module& pModule,
     81                       LDSection& pSection,
     82                       Input& pInput);
     83 
     84   // Handle partial linking
     85   void partialScanRelocation(Relocation& pReloc,
     86                              Module& pModule);
     87 
     88   HexagonLDBackend& getTarget() { return m_Target; }
     89 
     90   const HexagonLDBackend& getTarget() const { return m_Target; }
     91 
     92   const char* getName(Relocation::Type pType) const;
     93 
     94   Size getSize(Relocation::Type pType) const;
     95 
     96   const SymPLTMap& getSymPLTMap() const { return m_SymPLTMap; }
     97   SymPLTMap& getSymPLTMap() { return m_SymPLTMap; }
     98 
     99   const SymGOTMap& getSymGOTMap() const { return m_SymGOTMap; }
    100   SymGOTMap& getSymGOTMap() { return m_SymGOTMap; }
    101 
    102   const SymGOTPLTMap& getSymGOTPLTMap() const { return m_SymGOTPLTMap; }
    103   SymGOTPLTMap& getSymGOTPLTMap() { return m_SymGOTPLTMap; }
    104 
    105   const RelRelMap& getRelRelMap() const { return m_RelRelMap; }
    106   RelRelMap& getRelRelMap() { return m_RelRelMap; }
    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 { return 0; }
    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  protected:
    117   /// addCopyReloc - add a copy relocation into .rela.dyn for pSym
    118   /// @param pSym - A resolved copy symbol that defined in BSS section
    119   void addCopyReloc(ResolveInfo& pSym, HexagonLDBackend& pTarget);
    120 
    121   /// defineSymbolforCopyReloc - allocate a space in BSS section and
    122   /// and force define the copy of pSym to BSS section
    123   /// @return the output LDSymbol of the copy symbol
    124   LDSymbol& defineSymbolforCopyReloc(IRBuilder& pLinker,
    125                                      const ResolveInfo& pSym,
    126                                      HexagonLDBackend& pTarget);
    127 
    128  private:
    129   virtual void scanLocalReloc(Relocation& pReloc,
    130                               IRBuilder& pBuilder,
    131                               Module& pModule,
    132                               LDSection& pSection);
    133 
    134   virtual void scanGlobalReloc(Relocation& pReloc,
    135                                IRBuilder& pBuilder,
    136                                Module& pModule,
    137                                LDSection& pSection);
    138 
    139   HexagonLDBackend& m_Target;
    140   SymPLTMap m_SymPLTMap;
    141   SymGOTMap m_SymGOTMap;
    142   SymGOTPLTMap m_SymGOTPLTMap;
    143   RelRelMap m_RelRelMap;
    144 };
    145 
    146 }  // namespace mcld
    147 
    148 #endif  // TARGET_HEXAGON_HEXAGONRELOCATOR_H_
    149