File: target-select.h

package info (click to toggle)
binutils 2.28-5
  • links: PTS, VCS
  • area: main
  • in suites: stretch
  • size: 271,848 kB
  • sloc: ansic: 1,419,727; asm: 623,424; cpp: 125,042; exp: 64,226; makefile: 56,536; sh: 21,234; lisp: 15,206; yacc: 14,889; perl: 2,111; ada: 1,681; lex: 1,645; pascal: 1,438; cs: 879; sed: 195; python: 154; xml: 95; awk: 25
file content (278 lines) | stat: -rw-r--r-- 8,632 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
// target-select.h -- select a target for an object file  -*- C++ -*-

// Copyright (C) 2006-2017 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.

// This file is part of gold.

// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
// MA 02110-1301, USA.

#ifndef GOLD_TARGET_SELECT_H
#define GOLD_TARGET_SELECT_H

#include <vector>

#include "gold-threads.h"

namespace gold
{

class Input_file;
class Target;
class Target_selector;

// Used to set the target only once.

class Set_target_once : public Once
{
 public:
  Set_target_once(Target_selector* target_selector)
    : target_selector_(target_selector)
  { }

 protected:
  void
  do_run_once(void*);

 private:
  Target_selector* target_selector_;
};

// We want to avoid a master list of targets, which implies using a
// global constructor.  And we also want the program to start up as
// quickly as possible, which implies avoiding global constructors.
// We compromise on a very simple global constructor.  We use a target
// selector, which specifies an ELF machine number and a recognition
// function.  We use global constructors to build a linked list of
// target selectors--a simple pointer list, not a std::list.

class Target_selector
{
 public:
  // Create a target selector for a specific machine number, size (32
  // or 64), and endianness.  The machine number can be EM_NONE to
  // test for any machine number.  BFD_NAME is the name of the target
  // used by the GNU linker, for backward compatibility; it may be
  // NULL.  EMULATION is the name of the emulation used by the GNU
  // linker; it is similar to BFD_NAME.
  Target_selector(int machine, int size, bool is_big_endian,
		  const char* bfd_name, const char* emulation);

  virtual ~Target_selector()
  { }

  // If we can handle this target, return a pointer to a target
  // structure.  The size and endianness are known.
  Target*
  recognize(Input_file* input_file, off_t offset,
	    int machine, int osabi, int abiversion)
  { return this->do_recognize(input_file, offset, machine, osabi, abiversion); }

  // If NAME matches the target, return a pointer to a target
  // structure.
  Target*
  recognize_by_bfd_name(const char* name)
  { return this->do_recognize_by_bfd_name(name); }

  // Push all supported BFD names onto the vector.  This is only used
  // for help output.
  void
  supported_bfd_names(std::vector<const char*>* names)
  { this->do_supported_bfd_names(names); }

  // If NAME matches the target emulation, return a pointer to a
  // target structure.
  Target*
  recognize_by_emulation(const char* name)
  { return this->do_recognize_by_emulation(name); }

  // Push all supported emulations onto the vector.  This is only used
  // for help output.
  void
  supported_emulations(std::vector<const char*>* names)
  { this->do_supported_emulations(names); }

  // Return the next Target_selector in the linked list.
  Target_selector*
  next() const
  { return this->next_; }

  // Return the machine number this selector is looking for.  This can
  // be EM_NONE to match any machine number, in which case the
  // do_recognize hook will be responsible for matching the machine
  // number.
  int
  machine() const
  { return this->machine_; }

  // Return the size this is looking for (32 or 64).
  int
  get_size() const
  { return this->size_; }

  // Return the endianness this is looking for.
  bool
  is_big_endian() const
  { return this->is_big_endian_; }

  // Return the BFD name.  This may return NULL, in which case the
  // do_recognize_by_bfd_name hook will be responsible for matching
  // the BFD name.
  const char*
  bfd_name() const
  { return this->bfd_name_; }

  // Return the emulation.  This may return NULL, in which case the
  // do_recognize_by_emulation hook will be responsible for matching
  // the emulation.
  const char*
  emulation() const
  { return this->emulation_; }

  // The reverse mapping, for --print-output-format: if we
  // instantiated TARGET, return our BFD_NAME.  If we did not
  // instantiate it, return NULL.
  const char*
  target_bfd_name(const Target* target)
  { return this->do_target_bfd_name(target); }

 protected:
  // Return an instance of the real target.  This must be implemented
  // by the child class.
  virtual Target*
  do_instantiate_target() = 0;

  // Recognize an object file given a machine code, OSABI code, and
  // ELF version value.  When this is called we already know that they
  // match the machine_, size_, and is_big_endian_ fields.  The child
  // class may implement a different version of this to do additional
  // checks, or to check for multiple machine codes if the machine_
  // field is EM_NONE.
  virtual Target*
  do_recognize(Input_file*, off_t, int, int, int)
  { return this->instantiate_target(); }

  // Recognize a target by name.  When this is called we already know
  // that the name matches (or that the bfd_name_ field is NULL).  The
  // child class may implement a different version of this to
  // recognize more than one name.
  virtual Target*
  do_recognize_by_bfd_name(const char*)
  { return this->instantiate_target(); }

  // Return a list of supported BFD names.  The child class may
  // implement a different version of this to handle more than one
  // name.
  virtual void
  do_supported_bfd_names(std::vector<const char*>* names)
  {
    gold_assert(this->bfd_name_ != NULL);
    names->push_back(this->bfd_name_);
  }

  // Recognize a target by emulation.  When this is called we already
  // know that the name matches (or that the emulation_ field is
  // NULL).  The child class may implement a different version of this
  // to recognize more than one emulation.
  virtual Target*
  do_recognize_by_emulation(const char*)
  { return this->instantiate_target(); }

  // Return a list of supported emulations.  The child class may
  // implement a different version of this to handle more than one
  // emulation.
  virtual void
  do_supported_emulations(std::vector<const char*>* emulations)
  {
    gold_assert(this->emulation_ != NULL);
    emulations->push_back(this->emulation_);
  }

  // Map from target to BFD name.
  virtual const char*
  do_target_bfd_name(const Target*);

  // Instantiate the target and return it.
  Target*
  instantiate_target();

  // Return whether TARGET is the target we instantiated.
  bool
  is_our_target(const Target* target)
  { return target == this->instantiated_target_; }

 private:
  // Set the target.
  void
  set_target();

  friend class Set_target_once;

  // ELF machine code.
  const int machine_;
  // Target size--32 or 64.
  const int size_;
  // Whether the target is big endian.
  const bool is_big_endian_;
  // BFD name of target, for compatibility.
  const char* const bfd_name_;
  // GNU linker emulation for this target, for compatibility.
  const char* const emulation_;
  // Next entry in list built at global constructor time.
  Target_selector* next_;
  // The singleton Target structure--this points to an instance of the
  // real implementation.
  Target* instantiated_target_;
  // Used to set the target only once.
  Set_target_once set_target_once_;
};

// Select the target for an ELF file.

extern Target*
select_target(Input_file*, off_t,
	      int machine, int size, bool big_endian, int osabi,
	      int abiversion);

// Select a target using a BFD name.

extern Target*
select_target_by_bfd_name(const char* name);

// Select a target using a GNU linker emulation.

extern Target*
select_target_by_emulation(const char* name);

// Fill in a vector with the list of supported targets.  This returns
// a list of BFD names.

extern void
supported_target_names(std::vector<const char*>*);

// Fill in a vector with the list of supported emulations.

extern void
supported_emulation_names(std::vector<const char*>*);

// Print the output format, for the --print-output-format option.

extern void
print_output_format();

} // End namespace gold.

#endif // !defined(GOLD_TARGET_SELECT_H)