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 "object.h"
   8 #include "symtab.h"
   9 #include "reloc-types.h"
  10
  11 namespace gold
  12 {
  13
  14 // This function implements the generic part of reloc scanning.  This
  15 // is an inline function which takes a class whose operator()
  16 // implements the machine specific part of scanning.  We do it this
  17 // way to avoidmaking a function call for each relocation, and to
  18 // avoid repeating the generic code for each target.
  19
  20 template<int size, bool big_endian, typename Target_type, int sh_type,
  21          typename Scan>
  22 inline void
  23 scan_relocs(
  24     const General_options& options,
  25     Symbol_table* symtab,
  26     Layout* layout,
  27     Target_type* target,
  28     Sized_relobj<size, big_endian>* object,
  29     unsigned int data_shndx,
  30     const unsigned char* prelocs,
  31     size_t reloc_count,
  32     size_t local_count,
  33     const unsigned char* plocal_syms,
  34     Symbol** global_syms)
  35 {
  36   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
  37   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
  38   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
  39   Scan scan;
  40
  41   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
  42     {
  43       Reltype reloc(prelocs);
  44
  45       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
  46       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
  47       unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
  48
  49       if (r_sym < local_count)
  50         {
  51           gold_assert(plocal_syms != NULL);
  52           typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
  53                                                       + r_sym * sym_size);
  54           const unsigned int shndx = lsym.get_st_shndx();
  55           if (shndx < elfcpp::SHN_LORESERVE
  56               && shndx != elfcpp::SHN_UNDEF
  57               && !object->is_section_included(lsym.get_st_shndx()))
  58             {
  59               // RELOC is a relocation against a local symbol in a
  60               // section we are discarding.  We can ignore this
  61               // relocation.  It will eventually become a reloc
  62               // against the value zero.
  63               //
  64               // FIXME: We should issue a warning if this is an
  65               // allocated section; is this the best place to do it?
  66               //
  67               // FIXME: The old GNU linker would in some cases look
  68               // for the linkonce section which caused this section to
  69               // be discarded, and, if the other section was the same
  70               // size, change the reloc to refer to the other section.
  71               // That seems risky and weird to me, and I don't know of
  72               // any case where it is actually required.
  73
  74               continue;
  75             }
  76
  77           scan.local(options, symtab, layout, target, object, data_shndx,
  78                      reloc, r_type, lsym);
  79         }
  80       else
  81         {
  82           Symbol* gsym = global_syms[r_sym - local_count];
  83           gold_assert(gsym != NULL);
  84           if (gsym->is_forwarder())
  85             gsym = symtab->resolve_forwards(gsym);
  86
  87           scan.global(options, symtab, layout, target, object, data_shndx,
  88                       reloc, r_type, gsym);
  89         }
  90     }
  91 }
  92
  93 // This function implements the generic part of relocation processing.
  94 // This is an inline function which take a class whose operator()
  95 // implements the machine specific part of relocation.  We do it this
  96 // way to avoid making a function call for each relocation, and to
  97 // avoid repeating the generic relocation handling code for each
  98 // target.
  99
 100 // SIZE is the ELF size: 32 or 64.  BIG_ENDIAN is the endianness of
 101 // the data.  SH_TYPE is the section type: SHT_REL or SHT_RELA.
 102 // RELOCATE implements operator() to do a relocation.
 103
 104 // PRELOCS points to the relocation data.  RELOC_COUNT is the number
 105 // of relocs.  VIEW is the section data, VIEW_ADDRESS is its memory
 106 // address, and VIEW_SIZE is the size.
 107
 108 template<int size, bool big_endian, typename Target_type, int sh_type,
 109          typename Relocate>
 110 inline void
 111 relocate_section(
 112     const Relocate_info<size, big_endian>* relinfo,
 113     Target_type* target,
 114     const unsigned char* prelocs,
 115     size_t reloc_count,
 116     unsigned char* view,
 117     typename elfcpp::Elf_types<size>::Elf_Addr view_address,
 118     off_t view_size)
 119 {
 120   typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
 121   const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
 122   Relocate relocate;
 123
 124   unsigned int local_count = relinfo->local_symbol_count;
 125   const typename Sized_relobj<size, big_endian>::Local_values* local_values =
 126     relinfo->local_values;
 127   const Symbol* const * global_syms = relinfo->symbols;
 128
 129   for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
 130     {
 131       Reltype reloc(prelocs);
 132
 133       off_t offset = reloc.get_r_offset();
 134
 135       typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
 136       unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
 137       unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
 138
 139       const Sized_symbol<size>* sym;
 140
 141       Symbol_value<size> symval;
 142       const Symbol_value<size> *psymval;
 143       if (r_sym < local_count)
 144         {
 145           sym = NULL;
 146           psymval = &(*local_values)[r_sym];
 147         }
 148       else
 149         {
 150           const Symbol* gsym = global_syms[r_sym - local_count];
 151           gold_assert(gsym != NULL);
 152           if (gsym->is_forwarder())
 153             gsym = relinfo->symtab->resolve_forwards(gsym);
 154
 155           sym = static_cast<const Sized_symbol<size>*>(gsym);
 156           if (sym->has_symtab_index())
 157             symval.set_output_symtab_index(sym->symtab_index());
 158           else
 159             symval.set_no_output_symtab_entry();
 160           symval.set_output_value(sym->value());
 161           psymval = &symval;
 162         }
 163
 164       if (!relocate.relocate(relinfo, target, i, reloc, r_type, sym, psymval,
 165                              view + offset, view_address + offset, view_size))
 166         continue;
 167
 168       if (offset < 0 || offset >= view_size)
 169         {
 170           fprintf(stderr, _("%s: %s: reloc has bad offset %zu\n"),
 171                   program_name, relinfo->location(i, offset).c_str(),
 172                   static_cast<size_t>(offset));
 173           gold_exit(false);
 174         }
 175
 176       if (sym != NULL
 177           && sym->is_undefined()
 178           && sym->binding() != elfcpp::STB_WEAK)
 179         {
 180           fprintf(stderr, _("%s: %s: undefined reference to '%s'\n"),
 181                   program_name, relinfo->location(i, offset).c_str(),
 182                   sym->name());
 183           // gold_exit(false);
 184         }
 185
 186       if (sym != NULL && sym->has_warning())
 187         relinfo->symtab->issue_warning(sym, relinfo->location(i, offset));
 188     }
 189 }
 190
 191 } // End namespace gold.
 192
 193 #endif // !defined(GOLD_TARGET_RELOC_H)