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[/] [openrisc/] [trunk/] [gnu-src/] [binutils-2.20.1/] [gold/] [layout.h] - Blame information for rev 205

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// layout.h -- lay out output file sections for gold  -*- C++ -*-
2
 
3
// Copyright 2006, 2007, 2008, 2009 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
#ifndef GOLD_LAYOUT_H
24
#define GOLD_LAYOUT_H
25
 
26
#include <cstring>
27
#include <list>
28
#include <map>
29
#include <string>
30
#include <utility>
31
#include <vector>
32
 
33
#include "script.h"
34
#include "workqueue.h"
35
#include "object.h"
36
#include "dynobj.h"
37
#include "stringpool.h"
38
 
39
namespace gold
40
{
41
 
42
class General_options;
43
class Incremental_inputs;
44
class Input_objects;
45
class Mapfile;
46
class Symbol_table;
47
class Output_section_data;
48
class Output_section;
49
class Output_section_headers;
50
class Output_segment_headers;
51
class Output_file_header;
52
class Output_segment;
53
class Output_data;
54
class Output_data_dynamic;
55
class Output_symtab_xindex;
56
class Output_reduced_debug_abbrev_section;
57
class Output_reduced_debug_info_section;
58
class Eh_frame;
59
class Target;
60
 
61
// This task function handles mapping the input sections to output
62
// sections and laying them out in memory.
63
 
64
class Layout_task_runner : public Task_function_runner
65
{
66
 public:
67
  // OPTIONS is the command line options, INPUT_OBJECTS is the list of
68
  // input objects, SYMTAB is the symbol table, LAYOUT is the layout
69
  // object.
70
  Layout_task_runner(const General_options& options,
71
                     const Input_objects* input_objects,
72
                     Symbol_table* symtab,
73
                     Target* target,
74
                     Layout* layout,
75
                     Mapfile* mapfile)
76
    : options_(options), input_objects_(input_objects), symtab_(symtab),
77
      target_(target), layout_(layout), mapfile_(mapfile)
78
  { }
79
 
80
  // Run the operation.
81
  void
82
  run(Workqueue*, const Task*);
83
 
84
 private:
85
  Layout_task_runner(const Layout_task_runner&);
86
  Layout_task_runner& operator=(const Layout_task_runner&);
87
 
88
  const General_options& options_;
89
  const Input_objects* input_objects_;
90
  Symbol_table* symtab_;
91
  Target* target_;
92
  Layout* layout_;
93
  Mapfile* mapfile_;
94
};
95
 
96
// This class holds information about the comdat group or
97
// .gnu.linkonce section that will be kept for a given signature.
98
 
99
class Kept_section
100
{
101
 private:
102
  // For a comdat group, we build a mapping from the name of each
103
  // section in the group to the section index and the size in object.
104
  // When we discard a group in some other object file, we use this
105
  // map to figure out which kept section the discarded section is
106
  // associated with.  We then use that mapping when processing relocs
107
  // against discarded sections.
108
  struct Comdat_section_info
109
  {
110
    // The section index.
111
    unsigned int shndx;
112
    // The section size.
113
    uint64_t size;
114
 
115
    Comdat_section_info(unsigned int a_shndx, uint64_t a_size)
116
      : shndx(a_shndx), size(a_size)
117
    { }
118
  };
119
 
120
  // Most comdat groups have only one or two sections, so we use a
121
  // std::map rather than an Unordered_map to optimize for that case
122
  // without paying too heavily for groups with more sections.
123
  typedef std::map<std::string, Comdat_section_info> Comdat_group;
124
 
125
 public:
126
  Kept_section()
127
    : object_(NULL), shndx_(0), is_comdat_(false), is_group_name_(false)
128
  { this->u_.linkonce_size = 0; }
129
 
130
  // We need to support copies for the signature map in the Layout
131
  // object, but we should never copy an object after it has been
132
  // marked as a comdat section.
133
  Kept_section(const Kept_section& k)
134
    : object_(k.object_), shndx_(k.shndx_), is_comdat_(false),
135
      is_group_name_(k.is_group_name_)
136
  {
137
    gold_assert(!k.is_comdat_);
138
    this->u_.linkonce_size = 0;
139
  }
140
 
141
  ~Kept_section()
142
  {
143
    if (this->is_comdat_)
144
      delete this->u_.group_sections;
145
  }
146
 
147
  // The object where this section lives.
148
  Relobj*
149
  object() const
150
  { return this->object_; }
151
 
152
  // Set the object.
153
  void
154
  set_object(Relobj* object)
155
  {
156
    gold_assert(this->object_ == NULL);
157
    this->object_ = object;
158
  }
159
 
160
  // The section index.
161
  unsigned int
162
  shndx() const
163
  { return this->shndx_; }
164
 
165
  // Set the section index.
166
  void
167
  set_shndx(unsigned int shndx)
168
  {
169
    gold_assert(this->shndx_ == 0);
170
    this->shndx_ = shndx;
171
  }
172
 
173
  // Whether this is a comdat group.
174
  bool
175
  is_comdat() const
176
  { return this->is_comdat_; }
177
 
178
  // Set that this is a comdat group.
179
  void
180
  set_is_comdat()
181
  {
182
    gold_assert(!this->is_comdat_);
183
    this->is_comdat_ = true;
184
    this->u_.group_sections = new Comdat_group();
185
  }
186
 
187
  // Whether this is associated with the name of a group or section
188
  // rather than the symbol name derived from a linkonce section.
189
  bool
190
  is_group_name() const
191
  { return this->is_group_name_; }
192
 
193
  // Note that this represents a comdat group rather than a single
194
  // linkonce section.
195
  void
196
  set_is_group_name()
197
  { this->is_group_name_ = true; }
198
 
199
  // Add a section to the group list.
200
  void
201
  add_comdat_section(const std::string& name, unsigned int shndx,
202
                     uint64_t size)
203
  {
204
    gold_assert(this->is_comdat_);
205
    Comdat_section_info sinfo(shndx, size);
206
    this->u_.group_sections->insert(std::make_pair(name, sinfo));
207
  }
208
 
209
  // Look for a section name in the group list, and return whether it
210
  // was found.  If found, returns the section index and size.
211
  bool
212
  find_comdat_section(const std::string& name, unsigned int *pshndx,
213
                      uint64_t *psize) const
214
  {
215
    gold_assert(this->is_comdat_);
216
    Comdat_group::const_iterator p = this->u_.group_sections->find(name);
217
    if (p == this->u_.group_sections->end())
218
      return false;
219
    *pshndx = p->second.shndx;
220
    *psize = p->second.size;
221
    return true;
222
  }
223
 
224
  // If there is only one section in the group list, return true, and
225
  // return the section index and size.
226
  bool
227
  find_single_comdat_section(unsigned int *pshndx, uint64_t *psize) const
228
  {
229
    gold_assert(this->is_comdat_);
230
    if (this->u_.group_sections->size() != 1)
231
      return false;
232
    Comdat_group::const_iterator p = this->u_.group_sections->begin();
233
    *pshndx = p->second.shndx;
234
    *psize = p->second.size;
235
    return true;
236
  }
237
 
238
  // Return the size of a linkonce section.
239
  uint64_t
240
  linkonce_size() const
241
  {
242
    gold_assert(!this->is_comdat_);
243
    return this->u_.linkonce_size;
244
  }
245
 
246
  // Set the size of a linkonce section.
247
  void
248
  set_linkonce_size(uint64_t size)
249
  {
250
    gold_assert(!this->is_comdat_);
251
    this->u_.linkonce_size = size;
252
  }
253
 
254
 private:
255
  // No assignment.
256
  Kept_section& operator=(const Kept_section&);
257
 
258
  // The object containing the comdat group or .gnu.linkonce section.
259
  Relobj* object_;
260
  // Index of the group section for comdats and the section itself for
261
  // .gnu.linkonce.
262
  unsigned int shndx_;
263
  // True if this is for a comdat group rather than a .gnu.linkonce
264
  // section.
265
  bool is_comdat_;
266
  // The Kept_sections are values of a mapping, that maps names to
267
  // them.  This field is true if this struct is associated with the
268
  // name of a comdat or .gnu.linkonce, false if it is associated with
269
  // the name of a symbol obtained from the .gnu.linkonce.* name
270
  // through some heuristics.
271
  bool is_group_name_;
272
  union
273
  {
274
    // If the is_comdat_ field is true, this holds a map from names of
275
    // the sections in the group to section indexes in object_ and to
276
    // section sizes.
277
    Comdat_group* group_sections;
278
    // If the is_comdat_ field is false, this holds the size of the
279
    // single section.
280
    uint64_t linkonce_size;
281
  } u_;
282
};
283
 
284
// This class handles the details of laying out input sections.
285
 
286
class Layout
287
{
288
 public:
289
  Layout(int number_of_input_files, Script_options*);
290
 
291
  ~Layout()
292
  {
293
    delete this->relaxation_debug_check_;
294
    delete this->segment_states_;
295
  }
296
 
297
  // Given an input section SHNDX, named NAME, with data in SHDR, from
298
  // the object file OBJECT, return the output section where this
299
  // input section should go.  RELOC_SHNDX is the index of a
300
  // relocation section which applies to this section, or 0 if none,
301
  // or -1U if more than one.  RELOC_TYPE is the type of the
302
  // relocation section if there is one.  Set *OFFSET to the offset
303
  // within the output section.
304
  template<int size, bool big_endian>
305
  Output_section*
306
  layout(Sized_relobj<size, big_endian> *object, unsigned int shndx,
307
         const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
308
         unsigned int reloc_shndx, unsigned int reloc_type, off_t* offset);
309
 
310
  // Layout an input reloc section when doing a relocatable link.  The
311
  // section is RELOC_SHNDX in OBJECT, with data in SHDR.
312
  // DATA_SECTION is the reloc section to which it refers.  RR is the
313
  // relocatable information.
314
  template<int size, bool big_endian>
315
  Output_section*
316
  layout_reloc(Sized_relobj<size, big_endian>* object,
317
               unsigned int reloc_shndx,
318
               const elfcpp::Shdr<size, big_endian>& shdr,
319
               Output_section* data_section,
320
               Relocatable_relocs* rr);
321
 
322
  // Layout a group section when doing a relocatable link.
323
  template<int size, bool big_endian>
324
  void
325
  layout_group(Symbol_table* symtab,
326
               Sized_relobj<size, big_endian>* object,
327
               unsigned int group_shndx,
328
               const char* group_section_name,
329
               const char* signature,
330
               const elfcpp::Shdr<size, big_endian>& shdr,
331
               elfcpp::Elf_Word flags,
332
               std::vector<unsigned int>* shndxes);
333
 
334
  // Like layout, only for exception frame sections.  OBJECT is an
335
  // object file.  SYMBOLS is the contents of the symbol table
336
  // section, with size SYMBOLS_SIZE.  SYMBOL_NAMES is the contents of
337
  // the symbol name section, with size SYMBOL_NAMES_SIZE.  SHNDX is a
338
  // .eh_frame section in OBJECT.  SHDR is the section header.
339
  // RELOC_SHNDX is the index of a relocation section which applies to
340
  // this section, or 0 if none, or -1U if more than one.  RELOC_TYPE
341
  // is the type of the relocation section if there is one.  This
342
  // returns the output section, and sets *OFFSET to the offset.
343
  template<int size, bool big_endian>
344
  Output_section*
345
  layout_eh_frame(Sized_relobj<size, big_endian>* object,
346
                  const unsigned char* symbols,
347
                  off_t symbols_size,
348
                  const unsigned char* symbol_names,
349
                  off_t symbol_names_size,
350
                  unsigned int shndx,
351
                  const elfcpp::Shdr<size, big_endian>& shdr,
352
                  unsigned int reloc_shndx, unsigned int reloc_type,
353
                  off_t* offset);
354
 
355
  // Handle a GNU stack note.  This is called once per input object
356
  // file.  SEEN_GNU_STACK is true if the object file has a
357
  // .note.GNU-stack section.  GNU_STACK_FLAGS is the section flags
358
  // from that section if there was one.
359
  void
360
  layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags);
361
 
362
  // Add an Output_section_data to the layout.  This is used for
363
  // special sections like the GOT section.  IS_DYNAMIC_LINKER_SECTION
364
  // is true for sections which are used by the dynamic linker, such
365
  // as dynamic reloc sections.
366
  Output_section*
367
  add_output_section_data(const char* name, elfcpp::Elf_Word type,
368
                          elfcpp::Elf_Xword flags,
369
                          Output_section_data*, bool is_dynamic_linker_section);
370
 
371
  // Create dynamic sections if necessary.
372
  void
373
  create_initial_dynamic_sections(Symbol_table*);
374
 
375
  // Define __start and __stop symbols for output sections.
376
  void
377
  define_section_symbols(Symbol_table*);
378
 
379
  // Create automatic note sections.
380
  void
381
  create_notes();
382
 
383
  // Create sections for linker scripts.
384
  void
385
  create_script_sections()
386
  { this->script_options_->create_script_sections(this); }
387
 
388
  // Define symbols from any linker script.
389
  void
390
  define_script_symbols(Symbol_table* symtab)
391
  { this->script_options_->add_symbols_to_table(symtab); }
392
 
393
  // Define symbols for group signatures.
394
  void
395
  define_group_signatures(Symbol_table*);
396
 
397
  // Return the Stringpool used for symbol names.
398
  const Stringpool*
399
  sympool() const
400
  { return &this->sympool_; }
401
 
402
  // Return the Stringpool used for dynamic symbol names and dynamic
403
  // tags.
404
  const Stringpool*
405
  dynpool() const
406
  { return &this->dynpool_; }
407
 
408
  // Return the symtab_xindex section used to hold large section
409
  // indexes for the normal symbol table.
410
  Output_symtab_xindex*
411
  symtab_xindex() const
412
  { return this->symtab_xindex_; }
413
 
414
  // Return the dynsym_xindex section used to hold large section
415
  // indexes for the dynamic symbol table.
416
  Output_symtab_xindex*
417
  dynsym_xindex() const
418
  { return this->dynsym_xindex_; }
419
 
420
  // Return whether a section is a .gnu.linkonce section, given the
421
  // section name.
422
  static inline bool
423
  is_linkonce(const char* name)
424
  { return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; }
425
 
426
  // Return true if a section is a debugging section.
427
  static inline bool
428
  is_debug_info_section(const char* name)
429
  {
430
    // Debugging sections can only be recognized by name.
431
    return (strncmp(name, ".debug", sizeof(".debug") - 1) == 0
432
            || strncmp(name, ".gnu.linkonce.wi.",
433
                       sizeof(".gnu.linkonce.wi.") - 1) == 0
434
            || strncmp(name, ".line", sizeof(".line") - 1) == 0
435
            || strncmp(name, ".stab", sizeof(".stab") - 1) == 0);
436
  }
437
 
438
  // Check if a comdat group or .gnu.linkonce section with the given
439
  // NAME is selected for the link.  If there is already a section,
440
  // *KEPT_SECTION is set to point to the signature and the function
441
  // returns false.  Otherwise, OBJECT, SHNDX,IS_COMDAT, and
442
  // IS_GROUP_NAME are recorded for this NAME in the layout object,
443
  // *KEPT_SECTION is set to the internal copy and the function return
444
  // false.
445
  bool
446
  find_or_add_kept_section(const std::string& name, Relobj* object,
447
                           unsigned int shndx, bool is_comdat,
448
                           bool is_group_name, Kept_section** kept_section);
449
 
450
  // Finalize the layout after all the input sections have been added.
451
  off_t
452
  finalize(const Input_objects*, Symbol_table*, Target*, const Task*);
453
 
454
  // Return whether any sections require postprocessing.
455
  bool
456
  any_postprocessing_sections() const
457
  { return this->any_postprocessing_sections_; }
458
 
459
  // Return the size of the output file.
460
  off_t
461
  output_file_size() const
462
  { return this->output_file_size_; }
463
 
464
  // Return the TLS segment.  This will return NULL if there isn't
465
  // one.
466
  Output_segment*
467
  tls_segment() const
468
  { return this->tls_segment_; }
469
 
470
  // Return the normal symbol table.
471
  Output_section*
472
  symtab_section() const
473
  {
474
    gold_assert(this->symtab_section_ != NULL);
475
    return this->symtab_section_;
476
  }
477
 
478
  // Return the dynamic symbol table.
479
  Output_section*
480
  dynsym_section() const
481
  {
482
    gold_assert(this->dynsym_section_ != NULL);
483
    return this->dynsym_section_;
484
  }
485
 
486
  // Return the dynamic tags.
487
  Output_data_dynamic*
488
  dynamic_data() const
489
  { return this->dynamic_data_; }
490
 
491
  // Write out the output sections.
492
  void
493
  write_output_sections(Output_file* of) const;
494
 
495
  // Write out data not associated with an input file or the symbol
496
  // table.
497
  void
498
  write_data(const Symbol_table*, Output_file*) const;
499
 
500
  // Write out output sections which can not be written until all the
501
  // input sections are complete.
502
  void
503
  write_sections_after_input_sections(Output_file* of);
504
 
505
  // Return an output section named NAME, or NULL if there is none.
506
  Output_section*
507
  find_output_section(const char* name) const;
508
 
509
  // Return an output segment of type TYPE, with segment flags SET set
510
  // and segment flags CLEAR clear.  Return NULL if there is none.
511
  Output_segment*
512
  find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
513
                      elfcpp::Elf_Word clear) const;
514
 
515
  // Return the number of segments we expect to produce.
516
  size_t
517
  expected_segment_count() const;
518
 
519
  // Set a flag to indicate that an object file uses the static TLS model.
520
  void
521
  set_has_static_tls()
522
  { this->has_static_tls_ = true; }
523
 
524
  // Return true if any object file uses the static TLS model.
525
  bool
526
  has_static_tls() const
527
  { return this->has_static_tls_; }
528
 
529
  // Return the options which may be set by a linker script.
530
  Script_options*
531
  script_options()
532
  { return this->script_options_; }
533
 
534
  const Script_options*
535
  script_options() const
536
  { return this->script_options_; }
537
 
538
  // Return the object managing inputs in incremental build. NULL in
539
  // non-incremental builds.
540
  Incremental_inputs*
541
  incremental_inputs()
542
  { return this->incremental_inputs_; }
543
 
544
  // Compute and write out the build ID if needed.
545
  void
546
  write_build_id(Output_file*) const;
547
 
548
  // Rewrite output file in binary format.
549
  void
550
  write_binary(Output_file* in) const;
551
 
552
  // Print output sections to the map file.
553
  void
554
  print_to_mapfile(Mapfile*) const;
555
 
556
  // Dump statistical information to stderr.
557
  void
558
  print_stats() const;
559
 
560
  // A list of segments.
561
 
562
  typedef std::vector<Output_segment*> Segment_list;
563
 
564
  // A list of sections.
565
 
566
  typedef std::vector<Output_section*> Section_list;
567
 
568
  // The list of information to write out which is not attached to
569
  // either a section or a segment.
570
  typedef std::vector<Output_data*> Data_list;
571
 
572
  // Store the allocated sections into the section list.  This is used
573
  // by the linker script code.
574
  void
575
  get_allocated_sections(Section_list*) const;
576
 
577
  // Make a section for a linker script to hold data.
578
  Output_section*
579
  make_output_section_for_script(const char* name);
580
 
581
  // Make a segment.  This is used by the linker script code.
582
  Output_segment*
583
  make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags);
584
 
585
  // Return the number of segments.
586
  size_t
587
  segment_count() const
588
  { return this->segment_list_.size(); }
589
 
590
  // Map from section flags to segment flags.
591
  static elfcpp::Elf_Word
592
  section_flags_to_segment(elfcpp::Elf_Xword flags);
593
 
594
  // Attach sections to segments.
595
  void
596
  attach_sections_to_segments();
597
 
598
  // For relaxation clean up, we need to know output section data created
599
  // from a linker script.
600
  void
601
  new_output_section_data_from_script(Output_section_data* posd)
602
  {
603
    if (this->record_output_section_data_from_script_)
604
      this->script_output_section_data_list_.push_back(posd);
605
  }
606
 
607
  // Return section list.
608
  const Section_list&
609
  section_list() const
610
  { return this->section_list_; }
611
 
612
 private:
613
  Layout(const Layout&);
614
  Layout& operator=(const Layout&);
615
 
616
  // Mapping from input section names to output section names.
617
  struct Section_name_mapping
618
  {
619
    const char* from;
620
    int fromlen;
621
    const char* to;
622
    int tolen;
623
  };
624
  static const Section_name_mapping section_name_mapping[];
625
  static const int section_name_mapping_count;
626
 
627
  // During a relocatable link, a list of group sections and
628
  // signatures.
629
  struct Group_signature
630
  {
631
    // The group section.
632
    Output_section* section;
633
    // The signature.
634
    const char* signature;
635
 
636
    Group_signature()
637
      : section(NULL), signature(NULL)
638
    { }
639
 
640
    Group_signature(Output_section* sectiona, const char* signaturea)
641
      : section(sectiona), signature(signaturea)
642
    { }
643
  };
644
  typedef std::vector<Group_signature> Group_signatures;
645
 
646
  // Create a note section, filling in the header.
647
  Output_section*
648
  create_note(const char* name, int note_type, const char *section_name,
649
              size_t descsz, bool allocate, size_t* trailing_padding);
650
 
651
  // Create a note section for gold version.
652
  void
653
  create_gold_note();
654
 
655
  // Record whether the stack must be executable.
656
  void
657
  create_executable_stack_info();
658
 
659
  // Create a build ID note if needed.
660
  void
661
  create_build_id();
662
 
663
  // Link .stab and .stabstr sections.
664
  void
665
  link_stabs_sections();
666
 
667
  // Create .gnu_incremental_inputs and .gnu_incremental_strtab sections needed
668
  // for the next run of incremental linking to check what has changed.
669
  void
670
  create_incremental_info_sections();
671
 
672
  // Find the first read-only PT_LOAD segment, creating one if
673
  // necessary.
674
  Output_segment*
675
  find_first_load_seg();
676
 
677
  // Count the local symbols in the regular symbol table and the dynamic
678
  // symbol table, and build the respective string pools.
679
  void
680
  count_local_symbols(const Task*, const Input_objects*);
681
 
682
  // Create the output sections for the symbol table.
683
  void
684
  create_symtab_sections(const Input_objects*, Symbol_table*,
685
                         unsigned int, off_t*);
686
 
687
  // Create the .shstrtab section.
688
  Output_section*
689
  create_shstrtab();
690
 
691
  // Create the section header table.
692
  void
693
  create_shdrs(const Output_section* shstrtab_section, off_t*);
694
 
695
  // Create the dynamic symbol table.
696
  void
697
  create_dynamic_symtab(const Input_objects*, Symbol_table*,
698
                        Output_section** pdynstr,
699
                        unsigned int* plocal_dynamic_count,
700
                        std::vector<Symbol*>* pdynamic_symbols,
701
                        Versions* versions);
702
 
703
  // Assign offsets to each local portion of the dynamic symbol table.
704
  void
705
  assign_local_dynsym_offsets(const Input_objects*);
706
 
707
  // Finish the .dynamic section and PT_DYNAMIC segment.
708
  void
709
  finish_dynamic_section(const Input_objects*, const Symbol_table*);
710
 
711
  // Create the .interp section and PT_INTERP segment.
712
  void
713
  create_interp(const Target* target);
714
 
715
  // Create the version sections.
716
  void
717
  create_version_sections(const Versions*,
718
                          const Symbol_table*,
719
                          unsigned int local_symcount,
720
                          const std::vector<Symbol*>& dynamic_symbols,
721
                          const Output_section* dynstr);
722
 
723
  template<int size, bool big_endian>
724
  void
725
  sized_create_version_sections(const Versions* versions,
726
                                const Symbol_table*,
727
                                unsigned int local_symcount,
728
                                const std::vector<Symbol*>& dynamic_symbols,
729
                                const Output_section* dynstr);
730
 
731
  // Return whether to include this section in the link.
732
  template<int size, bool big_endian>
733
  bool
734
  include_section(Sized_relobj<size, big_endian>* object, const char* name,
735
                  const elfcpp::Shdr<size, big_endian>&);
736
 
737
  // Return the output section name to use given an input section
738
  // name.  Set *PLEN to the length of the name.  *PLEN must be
739
  // initialized to the length of NAME.
740
  static const char*
741
  output_section_name(const char* name, size_t* plen);
742
 
743
  // Return the number of allocated output sections.
744
  size_t
745
  allocated_output_section_count() const;
746
 
747
  // Return the output section for NAME, TYPE and FLAGS.
748
  Output_section*
749
  get_output_section(const char* name, Stringpool::Key name_key,
750
                     elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
751
                     bool is_interp, bool is_dynamic_linker_section);
752
 
753
  // Choose the output section for NAME in RELOBJ.
754
  Output_section*
755
  choose_output_section(const Relobj* relobj, const char* name,
756
                        elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
757
                        bool is_input_section, bool is_interp,
758
                        bool is_dynamic_linker_section);
759
 
760
  // Create a new Output_section.
761
  Output_section*
762
  make_output_section(const char* name, elfcpp::Elf_Word type,
763
                      elfcpp::Elf_Xword flags, bool is_interp,
764
                      bool is_dynamic_linker_section);
765
 
766
  // Attach a section to a segment.
767
  void
768
  attach_section_to_segment(Output_section*);
769
 
770
  // Attach an allocated section to a segment.
771
  void
772
  attach_allocated_section_to_segment(Output_section*);
773
 
774
  // Set the final file offsets of all the segments.
775
  off_t
776
  set_segment_offsets(const Target*, Output_segment*, unsigned int* pshndx);
777
 
778
  // Set the file offsets of the sections when doing a relocatable
779
  // link.
780
  off_t
781
  set_relocatable_section_offsets(Output_data*, unsigned int* pshndx);
782
 
783
  // Set the final file offsets of all the sections not associated
784
  // with a segment.  We set section offsets in three passes: the
785
  // first handles all allocated sections, the second sections that
786
  // require postprocessing, and the last the late-bound STRTAB
787
  // sections (probably only shstrtab, which is the one we care about
788
  // because it holds section names).
789
  enum Section_offset_pass
790
  {
791
    BEFORE_INPUT_SECTIONS_PASS,
792
    POSTPROCESSING_SECTIONS_PASS,
793
    STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
794
  };
795
  off_t
796
  set_section_offsets(off_t, Section_offset_pass pass);
797
 
798
  // Set the final section indexes of all the sections not associated
799
  // with a segment.  Returns the next unused index.
800
  unsigned int
801
  set_section_indexes(unsigned int pshndx);
802
 
803
  // Set the section addresses when using a script.
804
  Output_segment*
805
  set_section_addresses_from_script(Symbol_table*);
806
 
807
  // Find appropriate places or orphan sections in a script.
808
  void
809
  place_orphan_sections_in_script();
810
 
811
  // Return whether SEG1 comes before SEG2 in the output file.
812
  static bool
813
  segment_precedes(const Output_segment* seg1, const Output_segment* seg2);
814
 
815
  // Use to save and restore segments during relaxation. 
816
  typedef Unordered_map<const Output_segment*, const Output_segment*>
817
    Segment_states;
818
 
819
  // Save states of current output segments.
820
  void
821
  save_segments(Segment_states*);
822
 
823
  // Restore output segment states.
824
  void
825
  restore_segments(const Segment_states*);
826
 
827
  // Clean up after relaxation so that it is possible to lay out the
828
  // sections and segments again.
829
  void
830
  clean_up_after_relaxation();
831
 
832
  // Doing preparation work for relaxation.  This is factored out to make
833
  // Layout::finalized a bit smaller and easier to read.
834
  void
835
  prepare_for_relaxation();
836
 
837
  // Main body of the relaxation loop, which lays out the section.
838
  off_t
839
  relaxation_loop_body(int, Target*, Symbol_table*, Output_segment**,
840
                       Output_segment*, Output_segment_headers*,
841
                       Output_file_header*, unsigned int*);
842
 
843
  // A mapping used for kept comdats/.gnu.linkonce group signatures.
844
  typedef Unordered_map<std::string, Kept_section> Signatures;
845
 
846
  // Mapping from input section name/type/flags to output section.  We
847
  // use canonicalized strings here.
848
 
849
  typedef std::pair<Stringpool::Key,
850
                    std::pair<elfcpp::Elf_Word, elfcpp::Elf_Xword> > Key;
851
 
852
  struct Hash_key
853
  {
854
    size_t
855
    operator()(const Key& k) const;
856
  };
857
 
858
  typedef Unordered_map<Key, Output_section*, Hash_key> Section_name_map;
859
 
860
  // A comparison class for segments.
861
 
862
  struct Compare_segments
863
  {
864
    bool
865
    operator()(const Output_segment* seg1, const Output_segment* seg2)
866
    { return Layout::segment_precedes(seg1, seg2); }
867
  };
868
 
869
  typedef std::vector<Output_section_data*> Output_section_data_list;
870
 
871
  // Debug checker class.
872
  class Relaxation_debug_check
873
  {
874
   public:
875
    Relaxation_debug_check()
876
      : section_infos_()
877
    { }
878
 
879
    // Check that sections and special data are in reset states.
880
    void
881
    check_output_data_for_reset_values(const Layout::Section_list&,
882
                                       const Layout::Data_list&);
883
 
884
    // Record information of a section list.
885
    void
886
    read_sections(const Layout::Section_list&);
887
 
888
    // Verify a section list with recorded information.
889
    void
890
    verify_sections(const Layout::Section_list&);
891
 
892
   private:
893
    // Information we care about a section.
894
    struct Section_info
895
    {
896
      // Output section described by this.
897
      Output_section* output_section;
898
      // Load address.
899
      uint64_t address;
900
      // Data size.
901
      off_t data_size;
902
      // File offset.
903
      off_t offset;
904
    };
905
 
906
    // Section information.
907
    std::vector<Section_info> section_infos_;
908
  };
909
 
910
  // The number of input files, for sizing tables.
911
  int number_of_input_files_;
912
  // Information set by scripts or by command line options.
913
  Script_options* script_options_;
914
  // The output section names.
915
  Stringpool namepool_;
916
  // The output symbol names.
917
  Stringpool sympool_;
918
  // The dynamic strings, if needed.
919
  Stringpool dynpool_;
920
  // The list of group sections and linkonce sections which we have seen.
921
  Signatures signatures_;
922
  // The mapping from input section name/type/flags to output sections.
923
  Section_name_map section_name_map_;
924
  // The list of output segments.
925
  Segment_list segment_list_;
926
  // The list of output sections.
927
  Section_list section_list_;
928
  // The list of output sections which are not attached to any output
929
  // segment.
930
  Section_list unattached_section_list_;
931
  // The list of unattached Output_data objects which require special
932
  // handling because they are not Output_sections.
933
  Data_list special_output_list_;
934
  // The section headers.
935
  Output_section_headers* section_headers_;
936
  // A pointer to the PT_TLS segment if there is one.
937
  Output_segment* tls_segment_;
938
  // A pointer to the PT_GNU_RELRO segment if there is one.
939
  Output_segment* relro_segment_;
940
  // The SHT_SYMTAB output section.
941
  Output_section* symtab_section_;
942
  // The SHT_SYMTAB_SHNDX for the regular symbol table if there is one.
943
  Output_symtab_xindex* symtab_xindex_;
944
  // The SHT_DYNSYM output section if there is one.
945
  Output_section* dynsym_section_;
946
  // The SHT_SYMTAB_SHNDX for the dynamic symbol table if there is one.
947
  Output_symtab_xindex* dynsym_xindex_;
948
  // The SHT_DYNAMIC output section if there is one.
949
  Output_section* dynamic_section_;
950
  // The dynamic data which goes into dynamic_section_.
951
  Output_data_dynamic* dynamic_data_;
952
  // The exception frame output section if there is one.
953
  Output_section* eh_frame_section_;
954
  // The exception frame data for eh_frame_section_.
955
  Eh_frame* eh_frame_data_;
956
  // Whether we have added eh_frame_data_ to the .eh_frame section.
957
  bool added_eh_frame_data_;
958
  // The exception frame header output section if there is one.
959
  Output_section* eh_frame_hdr_section_;
960
  // The space for the build ID checksum if there is one.
961
  Output_section_data* build_id_note_;
962
  // The output section containing dwarf abbreviations
963
  Output_reduced_debug_abbrev_section* debug_abbrev_;
964
  // The output section containing the dwarf debug info tree
965
  Output_reduced_debug_info_section* debug_info_;
966
  // A list of group sections and their signatures.
967
  Group_signatures group_signatures_;
968
  // The size of the output file.
969
  off_t output_file_size_;
970
  // Whether we have attached the sections to the segments.
971
  bool sections_are_attached_;
972
  // Whether we have seen an object file marked to require an
973
  // executable stack.
974
  bool input_requires_executable_stack_;
975
  // Whether we have seen at least one object file with an executable
976
  // stack marker.
977
  bool input_with_gnu_stack_note_;
978
  // Whether we have seen at least one object file without an
979
  // executable stack marker.
980
  bool input_without_gnu_stack_note_;
981
  // Whether we have seen an object file that uses the static TLS model.
982
  bool has_static_tls_;
983
  // Whether any sections require postprocessing.
984
  bool any_postprocessing_sections_;
985
  // Whether we have resized the signatures_ hash table.
986
  bool resized_signatures_;
987
  // Whether we have created a .stab*str output section.
988
  bool have_stabstr_section_;
989
  // In incremental build, holds information check the inputs and build the
990
  // .gnu_incremental_inputs section.
991
  Incremental_inputs* incremental_inputs_;
992
  // Whether we record output section data created in script
993
  bool record_output_section_data_from_script_;
994
  // List of output data that needs to be removed at relexation clean up.
995
  Output_section_data_list script_output_section_data_list_;
996
  // Structure to save segment states before entering the relaxation loop.
997
  Segment_states* segment_states_;
998
  // A relaxation debug checker.  We only create one when in debugging mode.
999
  Relaxation_debug_check* relaxation_debug_check_;
1000
};
1001
 
1002
// This task handles writing out data in output sections which is not
1003
// part of an input section, or which requires special handling.  When
1004
// this is done, it unblocks both output_sections_blocker and
1005
// final_blocker.
1006
 
1007
class Write_sections_task : public Task
1008
{
1009
 public:
1010
  Write_sections_task(const Layout* layout, Output_file* of,
1011
                      Task_token* output_sections_blocker,
1012
                      Task_token* final_blocker)
1013
    : layout_(layout), of_(of),
1014
      output_sections_blocker_(output_sections_blocker),
1015
      final_blocker_(final_blocker)
1016
  { }
1017
 
1018
  // The standard Task methods.
1019
 
1020
  Task_token*
1021
  is_runnable();
1022
 
1023
  void
1024
  locks(Task_locker*);
1025
 
1026
  void
1027
  run(Workqueue*);
1028
 
1029
  std::string
1030
  get_name() const
1031
  { return "Write_sections_task"; }
1032
 
1033
 private:
1034
  class Write_sections_locker;
1035
 
1036
  const Layout* layout_;
1037
  Output_file* of_;
1038
  Task_token* output_sections_blocker_;
1039
  Task_token* final_blocker_;
1040
};
1041
 
1042
// This task handles writing out data which is not part of a section
1043
// or segment.
1044
 
1045
class Write_data_task : public Task
1046
{
1047
 public:
1048
  Write_data_task(const Layout* layout, const Symbol_table* symtab,
1049
                  Output_file* of, Task_token* final_blocker)
1050
    : layout_(layout), symtab_(symtab), of_(of), final_blocker_(final_blocker)
1051
  { }
1052
 
1053
  // The standard Task methods.
1054
 
1055
  Task_token*
1056
  is_runnable();
1057
 
1058
  void
1059
  locks(Task_locker*);
1060
 
1061
  void
1062
  run(Workqueue*);
1063
 
1064
  std::string
1065
  get_name() const
1066
  { return "Write_data_task"; }
1067
 
1068
 private:
1069
  const Layout* layout_;
1070
  const Symbol_table* symtab_;
1071
  Output_file* of_;
1072
  Task_token* final_blocker_;
1073
};
1074
 
1075
// This task handles writing out the global symbols.
1076
 
1077
class Write_symbols_task : public Task
1078
{
1079
 public:
1080
  Write_symbols_task(const Layout* layout, const Symbol_table* symtab,
1081
                     const Input_objects* input_objects,
1082
                     const Stringpool* sympool, const Stringpool* dynpool,
1083
                     Output_file* of, Task_token* final_blocker)
1084
    : layout_(layout), symtab_(symtab), input_objects_(input_objects),
1085
      sympool_(sympool), dynpool_(dynpool), of_(of),
1086
      final_blocker_(final_blocker)
1087
  { }
1088
 
1089
  // The standard Task methods.
1090
 
1091
  Task_token*
1092
  is_runnable();
1093
 
1094
  void
1095
  locks(Task_locker*);
1096
 
1097
  void
1098
  run(Workqueue*);
1099
 
1100
  std::string
1101
  get_name() const
1102
  { return "Write_symbols_task"; }
1103
 
1104
 private:
1105
  const Layout* layout_;
1106
  const Symbol_table* symtab_;
1107
  const Input_objects* input_objects_;
1108
  const Stringpool* sympool_;
1109
  const Stringpool* dynpool_;
1110
  Output_file* of_;
1111
  Task_token* final_blocker_;
1112
};
1113
 
1114
// This task handles writing out data in output sections which can't
1115
// be written out until all the input sections have been handled.
1116
// This is for sections whose contents is based on the contents of
1117
// other output sections.
1118
 
1119
class Write_after_input_sections_task : public Task
1120
{
1121
 public:
1122
  Write_after_input_sections_task(Layout* layout, Output_file* of,
1123
                                  Task_token* input_sections_blocker,
1124
                                  Task_token* final_blocker)
1125
    : layout_(layout), of_(of),
1126
      input_sections_blocker_(input_sections_blocker),
1127
      final_blocker_(final_blocker)
1128
  { }
1129
 
1130
  // The standard Task methods.
1131
 
1132
  Task_token*
1133
  is_runnable();
1134
 
1135
  void
1136
  locks(Task_locker*);
1137
 
1138
  void
1139
  run(Workqueue*);
1140
 
1141
  std::string
1142
  get_name() const
1143
  { return "Write_after_input_sections_task"; }
1144
 
1145
 private:
1146
  Layout* layout_;
1147
  Output_file* of_;
1148
  Task_token* input_sections_blocker_;
1149
  Task_token* final_blocker_;
1150
};
1151
 
1152
// This task function handles closing the file.
1153
 
1154
class Close_task_runner : public Task_function_runner
1155
{
1156
 public:
1157
  Close_task_runner(const General_options* options, const Layout* layout,
1158
                    Output_file* of)
1159
    : options_(options), layout_(layout), of_(of)
1160
  { }
1161
 
1162
  // Run the operation.
1163
  void
1164
  run(Workqueue*, const Task*);
1165
 
1166
 private:
1167
  const General_options* options_;
1168
  const Layout* layout_;
1169
  Output_file* of_;
1170
};
1171
 
1172
// A small helper function to align an address.
1173
 
1174
inline uint64_t
1175
align_address(uint64_t address, uint64_t addralign)
1176
{
1177
  if (addralign != 0)
1178
    address = (address + addralign - 1) &~ (addralign - 1);
1179
  return address;
1180
}
1181
 
1182
} // End namespace gold.
1183
 
1184
#endif // !defined(GOLD_LAYOUT_H)

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