gold/target-select.cc

   1 // target-select.cc -- select a target for an object file
   2
   3 // Copyright 2006, 2007, 2008, 2009, 2010 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)
  56   : machine_(machine), size_(size), is_big_endian_(is_big_endian),
  57     bfd_name_(bfd_name), instantiated_target_(NULL), set_target_once_(this)
  58 {
  59   this->next_ = target_selectors;
  60   target_selectors = this;
  61 }
  62
  63 // Instantiate the target and return it.  Use SET_TARGET_ONCE_ to
  64 // avoid instantiating two instances of the same target.
  65
  66 Target*
  67 Target_selector::instantiate_target()
  68 {
  69   this->set_target_once_.run_once(NULL);
  70   return this->instantiated_target_;
  71 }
  72
  73 // Instantiate the target.  This is called at most once.
  74
  75 void
  76 Target_selector::set_target()
  77 {
  78   gold_assert(this->instantiated_target_ == NULL);
  79   this->instantiated_target_ = this->do_instantiate_target();
  80 }
  81
  82 // Find the target for an ELF file.
  83
  84 Target*
  85 select_target(int machine, int size, bool is_big_endian, int osabi,
  86               int abiversion)
  87 {
  88   for (Target_selector* p = target_selectors; p != NULL; p = p->next())
  89     {
  90       int pmach = p->machine();
  91       if ((pmach == machine || pmach == elfcpp::EM_NONE)
  92           && p->get_size() == size
  93           && (p->is_big_endian() ? is_big_endian : !is_big_endian))
  94         {
  95           Target* ret = p->recognize(machine, osabi, abiversion);
  96           if (ret != NULL)
  97             return ret;
  98         }
  99     }
 100   return NULL;
 101 }
 102
 103 // Find a target using a BFD name.  This is used to support the
 104 // --oformat option.
 105
 106 Target*
 107 select_target_by_name(const char* name)
 108 {
 109   for (Target_selector* p = target_selectors; p != NULL; p = p->next())
 110     {
 111       const char* pname = p->bfd_name();
 112       if (pname == NULL || strcmp(pname, name) == 0)
 113         {
 114           Target* ret = p->recognize_by_name(name);
 115           if (ret != NULL)
 116             return ret;
 117         }
 118     }
 119   return NULL;
 120 }
 121
 122 // Push all the supported BFD names onto a vector.
 123
 124 void
 125 supported_target_names(std::vector<const char*>* names)
 126 {
 127   for (Target_selector* p = target_selectors; p != NULL; p = p->next())
 128     p->supported_names(names);
 129 }
 130
 131 } // End namespace gold.