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      1 //===- GOT.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 MCLD_GLOBAL_OFFSET_TABLE_H
     10 #define MCLD_GLOBAL_OFFSET_TABLE_H
     11 #ifdef ENABLE_UNITTEST
     12 #include <gtest.h>
     13 #endif
     14 
     15 #include <mcld/LD/LDSection.h>
     16 #include <mcld/LD/SectionData.h>
     17 #include <mcld/Fragment/TargetFragment.h>
     18 
     19 namespace mcld {
     20 
     21 class GOT;
     22 class LDSection;
     23 class ResolveInfo;
     24 
     25 /** \class GOT
     26  *  \brief The Global Offset Table
     27  */
     28 class GOT
     29 {
     30 protected:
     31   GOT(LDSection& pSection);
     32 
     33 public:
     34   typedef SectionData::iterator iterator;
     35   typedef SectionData::const_iterator const_iterator;
     36 
     37   template<size_t SIZE>
     38   class Entry : public TargetFragment
     39   {
     40   public:
     41     enum { EntrySize = SIZE };
     42 
     43   public:
     44     Entry(uint64_t pValue, SectionData* pParent)
     45       : TargetFragment(Fragment::Target, pParent),
     46         f_Value(pValue) {
     47     }
     48 
     49     virtual ~Entry() {}
     50 
     51     uint64_t getValue() const
     52     { return f_Value; }
     53 
     54     void setValue(uint64_t pValue)
     55     { f_Value = pValue; }
     56 
     57     // Override pure virtual function
     58     size_t size() const
     59     { return EntrySize; }
     60 
     61   protected:
     62     uint64_t f_Value;
     63   };
     64 
     65 public:
     66   virtual ~GOT();
     67 
     68   // ----- observers -----//
     69   uint64_t addr() const { return m_Section.addr(); }
     70   uint32_t size() const { return m_Section.size(); }
     71 
     72   const_iterator begin() const { return m_SectionData->begin(); }
     73   iterator       begin()       { return m_SectionData->begin(); }
     74   const_iterator end  () const { return m_SectionData->end();   }
     75   iterator       end  ()       { return m_SectionData->end();   }
     76 
     77   bool empty() const
     78   { return m_SectionData->empty(); }
     79 
     80   // finalizeSectionSize - set LDSection size
     81   virtual void finalizeSectionSize();
     82 
     83   /// reserve - reseve number of pNum of empty entries
     84   /// Before layout, we scan all relocations to determine if GOT entries are
     85   /// needed. If an entry is needed, the empty entry is reserved for layout
     86   /// to adjust the fragment offset. After that, we fill up the entries when
     87   /// applying relocations.
     88   virtual void reserve(size_t pNum = 1) = 0;
     89 
     90 protected:
     91   LDSection& m_Section;
     92   SectionData* m_SectionData;
     93 };
     94 
     95 } // namespace of mcld
     96 
     97 #endif
     98 
     99