gold/target-reloc.h

   1 // target-reloc.h -- target specific relocation support  -*- C++ -*-
   2
   3 #ifndef GOLD_TARGET_RELOC_H
   4 #define GOLD_TARGET_RELOC_H
   5
   6 #include "elfcpp.h"
   7 #include "symtab.h"
   8
   9 namespace gold
  10 {
  11
  12 // Pick the ELF relocation accessor class and the size based on
  13 // SH_TYPE, which is either SHT_REL or SHT_RELA.
  14
  15 template<int sh_type, int size, bool big_endian>
  16 struct Reloc_types;
  17
  18 template<int size, bool big_endian>
  19 struct Reloc_types<elfcpp::SHT_REL, size, big_endian>
  20 {
  21   typedef typename elfcpp::Rel<size, big_endian> Reloc;
  22   static const int reloc_size = elfcpp::Elf_sizes<size>::rel_size;
  23 };
  24
  25 template<int size, bool big_endian>
  26 struct Reloc_types<elfcpp::SHT_RELA, size, big_endian>
  27 {
  28   typedef typename elfcpp::Rela<size, big_endian> Reloc;
  29   static const int reloc_size = elfcpp::Elf_sizes<size>::rela_size;
  30 };
  31
  32 // This function implements the generic part of relocation handling.
  33 // This is an inline function which take a class whose operator()
  34 // implements the machine specific part of relocation.  We do it this
  35 // way to avoid making a function call for each relocation, and to
  36 // avoid repeating the generic relocation handling code for each
  37 // target.
  38
  39 // SIZE is the ELF size: 32 or 64.  BIG_ENDIAN is the endianness of
  40 // the data.  SH_TYPE is the section type: SHT_REL or SHT_RELA.  RELOC
  41 // implements operator() to do a relocation.
  42
  43 // OBJECT is the object for we are processing relocs.  SH_TYPE is the
  44 // type of relocation: SHT_REL or SHT_RELA.  PRELOCS points to the
  45 // relocation data.  RELOC_COUNT is the number of relocs.  LOCAL_COUNT
  46 // is the number of local symbols.  LOCAL_VALUES holds the values of
  47 // the local symbols.  GLOBAL_SYMS points to the global symbols.  VIEW
  48 // is the section data, VIEW_ADDRESS is its memory address, and
  49 // VIEW_SIZE is the size.
  50
  51 template<int size, bool big_endian, int sh_type, typename Relocate>
  52 inline void
  53 relocate_section(
  54     const Symbol_table* symtab,
  55     Sized_object<size, big_endian>* object,
  56     const unsigned char* prelocs,
  57     size_t reloc_count,
  58     size_t local_count,
  59     const typename elfcpp::Elf_types<size>::Elf_Addr* local_values,
  60     Symbol** global_syms,
  61     unsigned char* view,
  62     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
  63     off_t view_size)
  64 {
  65   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
  66   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
  67   Relocate relocate;
  68
  69   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
  70     {
  71       Reltype reloc(prelocs);
  72
  73       off_t offset = reloc.get_r_offset();
  74       if (offset < 0 || offset >= view_size)
  75         {
  76           fprintf(stderr, _("%s: %s: reloc %zu has bad offset %lu\n"),
  77                   program_name, object->name().c_str(), i,
  78                   static_cast<unsigned long>(offset));
  79           gold_exit(false);
  80         }
  81
  82       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
  83       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
  84       unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
  85
  86       Sized_symbol<size>* sym;
  87       typename elfcpp::Elf_types<size>::Elf_Addr value;
  88
  89       if (r_sym < local_count)
  90         {
  91           sym = NULL;
  92           value = local_values[r_sym];
  93         }
  94       else
  95         {
  96           Symbol* gsym = global_syms[r_sym - local_count];
  97           if (gsym->is_forwarder())
  98             gsym = symtab->resolve_forwards(gsym);
  99
 100           sym = static_cast<Sized_symbol<size>*>(gsym);
 101           value = sym->value();
 102
 103           if (sym->shnum() == elfcpp::SHN_UNDEF
 104               && sym->binding() != elfcpp::STB_WEAK)
 105             {
 106               fprintf(stderr, _("%s: %s: undefined reference to '%s'\n"),
 107                       program_name, object->name().c_str(), sym->name());
 108               // gold_exit(false);
 109             }
 110         }
 111
 112       relocate(object, reloc, r_type, sym, value, view + offset,
 113                view_address + offset);
 114     }
 115 }
 116
 117 } // End namespace gold.
 118
 119 #endif // !defined(GOLD_TARGET_RELOC_H)