gold/target-select.cc

   1 // target-select.cc -- select a target for an object file
   2
   3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@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
  25 #include <cstring>
  26
  27 #include "elfcpp.h"
  28 #include "target-select.h"
  29
  30 namespace
  31 {
  32
  33 // The start of the list of target selectors.
  34
  35 gold::Target_selector* target_selectors;
  36
  37 } // End anonymous namespace.
  38
  39 namespace gold
  40 {
  41
  42 // Class Set_target_once.
  43
  44 void
  45 Set_target_once::do_run_once(void*)
  46 {
  47   this->target_selector_->set_target();
  48 }
  49
  50 // Construct a Target_selector, which means adding it to the linked
  51 // list.  This runs at global constructor time, so we want it to be
  52 // fast.
  53
  54 Target_selector::Target_selector(int machine, int size, bool is_big_endian,
  55                                  const char* bfd_name, const char* emulation)
  56   : machine_(machine), size_(size), is_big_endian_(is_big_endian),
  57     bfd_name_(bfd_name), emulation_(emulation), instantiated_target_(NULL),
  58     set_target_once_(this)
  59 {
  60   this->next_ = target_selectors;
  61   target_selectors = this;
  62 }
  63
  64 // Instantiate the target and return it.  Use SET_TARGET_ONCE_ to
  65 // avoid instantiating two instances of the same target.
  66
  67 Target*
  68 Target_selector::instantiate_target()
  69 {
  70   this->set_target_once_.run_once(NULL);
  71   return this->instantiated_target_;
  72 }
  73
  74 // Instantiate the target.  This is called at most once.
  75
  76 void
  77 Target_selector::set_target()
  78 {
  79   gold_assert(this->instantiated_target_ == NULL);
  80   this->instantiated_target_ = this->do_instantiate_target();
  81 }
  82
  83 // Find the target for an ELF file.
  84
  85 Target*
  86 select_target(int machine, int size, bool is_big_endian, int osabi,
  87               int abiversion)
  88 {
  89   for (Target_selector* p = target_selectors; p != NULL; p = p->next())
  90     {
  91       int pmach = p->machine();
  92       if ((pmach == machine || pmach == elfcpp::EM_NONE)
  93           && p->get_size() == size
  94           && (p->is_big_endian() ? is_big_endian : !is_big_endian))
  95         {
  96           Target* ret = p->recognize(machine, osabi, abiversion);
  97           if (ret != NULL)
  98             return ret;
  99         }
 100     }
 101   return NULL;
 102 }
 103
 104 // Find a target using a BFD name.  This is used to support the
 105 // --oformat option.
 106
 107 Target*
 108 select_target_by_bfd_name(const char* name)
 109 {
 110   for (Target_selector* p = target_selectors; p != NULL; p = p->next())
 111     {
 112       const char* pname = p->bfd_name();
 113       if (pname == NULL || strcmp(pname, name) == 0)
 114         {
 115           Target* ret = p->recognize_by_bfd_name(name);
 116           if (ret != NULL)
 117             return ret;
 118         }
 119     }
 120   return NULL;
 121 }
 122
 123 // Find a target using a GNU linker emulation.  This is used to
 124 // support the -m option.
 125
 126 Target*
 127 select_target_by_emulation(const char* name)
 128 {
 129   for (Target_selector* p = target_selectors; p != NULL; p = p->next())
 130     {
 131       const char* pname = p->emulation();
 132       if (pname == NULL || strcmp(pname, name) == 0)
 133         {
 134           Target* ret = p->recognize_by_emulation(name);
 135           if (ret != NULL)
 136             return ret;
 137         }
 138     }
 139   return NULL;
 140 }
 141
 142 // Push all the supported BFD names onto a vector.
 143
 144 void
 145 supported_target_names(std::vector<const char*>* names)
 146 {
 147   for (Target_selector* p = target_selectors; p != NULL; p = p->next())
 148     p->supported_bfd_names(names);
 149 }
 150
 151 // Push all the supported emulations onto a vector.
 152
 153 void
 154 supported_emulation_names(std::vector<const char*>* names)
 155 {
 156   for (Target_selector* p = target_selectors; p != NULL; p = p->next())
 157     p->supported_emulations(names);
 158 }
 159
 160 } // End namespace gold.