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
30namespace
31{
32
33// The start of the list of target selectors.
34
35gold::Target_selector* target_selectors;
36
37} // End anonymous namespace.
38
39namespace gold
40{
41
42// Class Set_target_once.
43
44void
45Set_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
54Target_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
66Target*
67Target_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
75void
76Target_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
84Target*
85select_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
106Target*
107select_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
124void
125supported_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.
132