gold/target.cc

   1 // target.cc
   2
   3 // Copyright 2009 Free Software Foundation, Inc.
   4 // Written by Doug Kwan <dougkwan@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #include "gold.h"
  24 #include "target.h"
  25 #include "dynobj.h"
  26
  27 namespace gold
  28 {
  29
  30 // Return whether NAME is a local label name.  This is used to implement the
  31 // --discard-locals options and can be overriden by children classes to
  32 // implement system-specific behaviour.  The logic here is the same as that
  33 // in _bfd_elf_is_local_label_name().
  34
  35 bool
  36 Target::do_is_local_label_name (const char* name) const
  37 {
  38   // Normal local symbols start with ``.L''.
  39   if (name[0] == '.' && name[1] == 'L')
  40     return true;
  41
  42   // At least some SVR4 compilers (e.g., UnixWare 2.1 cc) generate
  43   // DWARF debugging symbols starting with ``..''.
  44   if (name[0] == '.' && name[1] == '.')
  45     return true;
  46
  47   // gcc will sometimes generate symbols beginning with ``_.L_'' when
  48   // emitting DWARF debugging output.  I suspect this is actually a
  49   // small bug in gcc (it calls ASM_OUTPUT_LABEL when it should call
  50   // ASM_GENERATE_INTERNAL_LABEL, and this causes the leading
  51   // underscore to be emitted on some ELF targets).  For ease of use,
  52   // we treat such symbols as local.
  53   if (name[0] == '_' && name[1] == '.' && name[2] == 'L' && name[3] == '_')
  54     return true;
  55
  56   return false;
  57 }
  58
  59 // Implementations of methods Target::do_make_elf_object are almost identical
  60 // except for the address sizes and endianities.  So we extract this
  61 // into a template.
  62
  63 template<int size, bool big_endian>
  64 inline Object*
  65 Target::do_make_elf_object_implementation(
  66     const std::string& name,
  67     Input_file* input_file,
  68     off_t offset,
  69     const elfcpp::Ehdr<size, big_endian>& ehdr)
  70 {
  71   int et = ehdr.get_e_type();
  72   if (et == elfcpp::ET_REL)
  73     {
  74       Sized_relobj<size, big_endian>* obj =
  75         new Sized_relobj<size, big_endian>(name, input_file, offset, ehdr);
  76       obj->setup(this);
  77       return obj;
  78     }
  79   else if (et == elfcpp::ET_DYN)
  80     {
  81       Sized_dynobj<size, big_endian>* obj =
  82         new Sized_dynobj<size, big_endian>(name, input_file, offset, ehdr);
  83       obj->setup(this);
  84       return obj;
  85     }
  86   else
  87     {
  88       gold_error(_("%s: unsupported ELF file type %d"),
  89                  name.c_str(), et);
  90       return NULL;
  91     }
  92 }
  93
  94 // Make an ELF object called NAME by reading INPUT_FILE at OFFSET.  EHDR
  95 // is the ELF header of the object.  There are four versions of this
  96 // for different address sizes and endianities.
  97
  98 #ifdef HAVE_TARGET_32_LITTLE
  99 Object*
 100 Target::do_make_elf_object(const std::string& name, Input_file* input_file,
 101                            off_t offset, const elfcpp::Ehdr<32, false>& ehdr)
 102 {
 103   return this->do_make_elf_object_implementation<32, false>(name, input_file,
 104                                                             offset, ehdr);
 105 }
 106 #endif
 107
 108 #ifdef HAVE_TARGET_32_BIG
 109 Object*
 110 Target::do_make_elf_object(const std::string& name, Input_file* input_file,
 111                            off_t offset, const elfcpp::Ehdr<32, true>& ehdr)
 112 {
 113   return this->do_make_elf_object_implementation<32, true>(name, input_file,
 114                                                            offset, ehdr);
 115 }
 116 #endif
 117
 118 #ifdef HAVE_TARGET_64_LITTLE
 119 Object*
 120 Target::do_make_elf_object(const std::string& name, Input_file* input_file,
 121                            off_t offset, const elfcpp::Ehdr<64, false>& ehdr)
 122 {
 123   return this->do_make_elf_object_implementation<64, false>(name, input_file,
 124                                                             offset, ehdr);
 125 }
 126 #endif
 127
 128 #ifdef HAVE_TARGET_64_BIG
 129 Object*
 130 Target::do_make_elf_object(const std::string& name, Input_file* input_file,
 131                            off_t offset, const elfcpp::Ehdr<64, true>& ehdr)
 132 {
 133   return this->do_make_elf_object_implementation<64, true>(name, input_file,
 134                                                            offset, ehdr);
 135 }
 136 #endif
 137
 138 } // End namespace gold.