gold/target-select.cc

   1 // target-select.cc -- select a target for an object file
   2
   3 // Copyright 2006, 2007, 2008 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 // Construct a Target_selector, which means adding it to the linked
  43 // list.  This runs at global constructor time, so we want it to be
  44 // fast.
  45
  46 Target_selector::Target_selector(int machine, int size, bool is_big_endian,
  47                                  const char* bfd_name)
  48   : machine_(machine), size_(size), is_big_endian_(is_big_endian),
  49     bfd_name_(bfd_name), instantiated_target_(NULL), lock_(NULL),
  50     initialize_lock_(&this->lock_)
  51
  52 {
  53   this->next_ = target_selectors;
  54   target_selectors = this;
  55 }
  56
  57 // Instantiate the target and return it.  Use a lock to avoid
  58 // instantiating two instances of the same target.
  59
  60 Target*
  61 Target_selector::instantiate_target()
  62 {
  63   // We assume that the pointer will either be written entirely or not
  64   // at all.
  65   if (this->instantiated_target_ == NULL)
  66     {
  67       this->initialize_lock_.initialize();
  68       Hold_optional_lock hl(this->lock_);
  69       if (this->instantiated_target_ == NULL)
  70         this->instantiated_target_ = this->do_instantiate_target();
  71     }
  72   return this->instantiated_target_;
  73 }
  74
  75 // Find the target for an ELF file.
  76
  77 Target*
  78 select_target(int machine, int size, bool is_big_endian, int osabi,
  79               int abiversion)
  80 {
  81   for (Target_selector* p = target_selectors; p != NULL; p = p->next())
  82     {
  83       int pmach = p->machine();
  84       if ((pmach == machine || pmach == elfcpp::EM_NONE)
  85           && p->get_size() == size
  86           && (p->is_big_endian() ? is_big_endian : !is_big_endian))
  87         {
  88           Target* ret = p->recognize(machine, osabi, abiversion);
  89           if (ret != NULL)
  90             return ret;
  91         }
  92     }
  93   return NULL;
  94 }
  95
  96 // Find a target using a BFD name.  This is used to support the
  97 // --oformat option.
  98
  99 Target*
 100 select_target_by_name(const char* name)
 101 {
 102   for (Target_selector* p = target_selectors; p != NULL; p = p->next())
 103     {
 104       const char* pname = p->bfd_name();
 105       if (pname == NULL || strcmp(pname, name) == 0)
 106         {
 107           Target* ret = p->recognize_by_name(name);
 108           if (ret != NULL)
 109             return ret;
 110         }
 111     }
 112   return NULL;
 113 }
 114
 115 // Push all the supported BFD names onto a vector.
 116
 117 void
 118 supported_target_names(std::vector<const char*>* names)
 119 {
 120   for (Target_selector* p = target_selectors; p != NULL; p = p->next())
 121     p->supported_names(names);
 122 }
 123
 124 } // End namespace gold.