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[/] [openrisc/] [trunk/] [gnu-stable/] [binutils-2.20.1/] [gold/] [merge.cc] - Blame information for rev 818

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1 205 julius
// merge.cc -- handle section merging for gold
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 <cstdlib>
26
#include <algorithm>
27
 
28
#include "merge.h"
29
 
30
namespace gold
31
{
32
 
33
// Class Object_merge_map.
34
 
35
// Destructor.
36
 
37
Object_merge_map::~Object_merge_map()
38
{
39
  for (Section_merge_maps::iterator p = this->section_merge_maps_.begin();
40
       p != this->section_merge_maps_.end();
41
       ++p)
42
    delete p->second;
43
}
44
 
45
// Get the Input_merge_map to use for an input section, or NULL.
46
 
47
Object_merge_map::Input_merge_map*
48
Object_merge_map::get_input_merge_map(unsigned int shndx)
49
{
50
  gold_assert(shndx != -1U);
51
  if (shndx == this->first_shnum_)
52
    return &this->first_map_;
53
  if (shndx == this->second_shnum_)
54
    return &this->second_map_;
55
  Section_merge_maps::const_iterator p = this->section_merge_maps_.find(shndx);
56
  if (p != this->section_merge_maps_.end())
57
    return p->second;
58
  return NULL;
59
}
60
 
61
// Get or create the Input_merge_map to use for an input section.
62
 
63
Object_merge_map::Input_merge_map*
64
Object_merge_map::get_or_make_input_merge_map(const Merge_map* merge_map,
65
                                              unsigned int shndx)
66
{
67
  Input_merge_map* map = this->get_input_merge_map(shndx);
68
  if (map != NULL)
69
    {
70
      // For a given input section in a given object, every mapping
71
      // must be done with the same Merge_map.
72
      gold_assert(map->merge_map == merge_map);
73
      return map;
74
    }
75
 
76
  // We need to create a new entry.
77
  if (this->first_shnum_ == -1U)
78
    {
79
      this->first_shnum_ = shndx;
80
      this->first_map_.merge_map = merge_map;
81
      return &this->first_map_;
82
    }
83
  if (this->second_shnum_ == -1U)
84
    {
85
      this->second_shnum_ = shndx;
86
      this->second_map_.merge_map = merge_map;
87
      return &this->second_map_;
88
    }
89
 
90
  Input_merge_map* new_map = new Input_merge_map;
91
  new_map->merge_map = merge_map;
92
  this->section_merge_maps_[shndx] = new_map;
93
  return new_map;
94
}
95
 
96
// Add a mapping.
97
 
98
void
99
Object_merge_map::add_mapping(const Merge_map* merge_map, unsigned int shndx,
100
                              section_offset_type input_offset,
101
                              section_size_type length,
102
                              section_offset_type output_offset)
103
{
104
  Input_merge_map* map = this->get_or_make_input_merge_map(merge_map, shndx);
105
 
106
  // Try to merge the new entry in the last one we saw.
107
  if (!map->entries.empty())
108
    {
109
      Input_merge_entry& entry(map->entries.back());
110
 
111
      // Use section_size_type to avoid signed/unsigned warnings.
112
      section_size_type input_offset_u = input_offset;
113
      section_size_type output_offset_u = output_offset;
114
 
115
      // If this entry is not in order, we need to sort the vector
116
      // before looking anything up.
117
      if (input_offset_u < entry.input_offset + entry.length)
118
        {
119
          gold_assert(input_offset < entry.input_offset);
120
          gold_assert(input_offset_u + length
121
                      <= static_cast<section_size_type>(entry.input_offset));
122
          map->sorted = false;
123
        }
124
      else if (entry.input_offset + entry.length == input_offset_u
125
               && (output_offset == -1
126
                   ? entry.output_offset == -1
127
                   : entry.output_offset + entry.length == output_offset_u))
128
        {
129
          entry.length += length;
130
          return;
131
        }
132
    }
133
 
134
  Input_merge_entry entry;
135
  entry.input_offset = input_offset;
136
  entry.length = length;
137
  entry.output_offset = output_offset;
138
  map->entries.push_back(entry);
139
}
140
 
141
// Get the output offset for an input address.
142
 
143
bool
144
Object_merge_map::get_output_offset(const Merge_map* merge_map,
145
                                    unsigned int shndx,
146
                                    section_offset_type input_offset,
147
                                    section_offset_type *output_offset)
148
{
149
  Input_merge_map* map = this->get_input_merge_map(shndx);
150
  if (map == NULL
151
      || (merge_map != NULL && map->merge_map != merge_map))
152
    return false;
153
 
154
  if (!map->sorted)
155
    {
156
      std::sort(map->entries.begin(), map->entries.end(),
157
                Input_merge_compare());
158
      map->sorted = true;
159
    }
160
 
161
  Input_merge_entry entry;
162
  entry.input_offset = input_offset;
163
  std::vector<Input_merge_entry>::const_iterator p =
164
    std::lower_bound(map->entries.begin(), map->entries.end(),
165
                     entry, Input_merge_compare());
166
  if (p == map->entries.end() || p->input_offset > input_offset)
167
    {
168
      if (p == map->entries.begin())
169
        return false;
170
      --p;
171
      gold_assert(p->input_offset <= input_offset);
172
    }
173
 
174
  if (input_offset - p->input_offset
175
      >= static_cast<section_offset_type>(p->length))
176
    return false;
177
 
178
  *output_offset = p->output_offset;
179
  if (*output_offset != -1)
180
    *output_offset += (input_offset - p->input_offset);
181
  return true;
182
}
183
 
184
// Return whether this is the merge map for section SHNDX.
185
 
186
inline bool
187
Object_merge_map::is_merge_section_for(const Merge_map* merge_map,
188
                                       unsigned int shndx)
189
{
190
  Input_merge_map* map = this->get_input_merge_map(shndx);
191
  return map != NULL && map->merge_map == merge_map;
192
}
193
 
194
// Initialize a mapping from input offsets to output addresses.
195
 
196
template<int size>
197
void
198
Object_merge_map::initialize_input_to_output_map(
199
    unsigned int shndx,
200
    typename elfcpp::Elf_types<size>::Elf_Addr starting_address,
201
    Unordered_map<section_offset_type,
202
                  typename elfcpp::Elf_types<size>::Elf_Addr>* initialize_map)
203
{
204
  Input_merge_map* map = this->get_input_merge_map(shndx);
205
  gold_assert(map != NULL);
206
 
207
  gold_assert(initialize_map->empty());
208
  // We know how many entries we are going to add.
209
  // reserve_unordered_map takes an expected count of buckets, not a
210
  // count of elements, so double it to try to reduce collisions.
211
  reserve_unordered_map(initialize_map, map->entries.size() * 2);
212
 
213
  for (Input_merge_map::Entries::const_iterator p = map->entries.begin();
214
       p != map->entries.end();
215
       ++p)
216
    {
217
      section_offset_type output_offset = p->output_offset;
218
      if (output_offset != -1)
219
        output_offset += starting_address;
220
      else
221
        {
222
          // If we see a relocation against an address we have chosen
223
          // to discard, we relocate to zero.  FIXME: We could also
224
          // issue a warning in this case; that would require
225
          // reporting this somehow and checking it in the routines in
226
          // reloc.h.
227
          output_offset = 0;
228
        }
229
      initialize_map->insert(std::make_pair(p->input_offset, output_offset));
230
    }
231
}
232
 
233
// Class Merge_map.
234
 
235
// Add a mapping for the bytes from OFFSET to OFFSET + LENGTH in input
236
// section SHNDX in object OBJECT to an OUTPUT_OFFSET in merged data
237
// in an output section.
238
 
239
void
240
Merge_map::add_mapping(Relobj* object, unsigned int shndx,
241
                       section_offset_type offset, section_size_type length,
242
                       section_offset_type output_offset)
243
{
244
  Object_merge_map* object_merge_map = object->merge_map();
245
  if (object_merge_map == NULL)
246
    {
247
      object_merge_map = new Object_merge_map();
248
      object->set_merge_map(object_merge_map);
249
    }
250
 
251
  object_merge_map->add_mapping(this, shndx, offset, length, output_offset);
252
}
253
 
254
// Return the output offset for an input address.  The input address
255
// is at offset OFFSET in section SHNDX in OBJECT.  This sets
256
// *OUTPUT_OFFSET to the offset in the merged data in the output
257
// section.  This returns true if the mapping is known, false
258
// otherwise.
259
 
260
bool
261
Merge_map::get_output_offset(const Relobj* object, unsigned int shndx,
262
                             section_offset_type offset,
263
                             section_offset_type* output_offset) const
264
{
265
  Object_merge_map* object_merge_map = object->merge_map();
266
  if (object_merge_map == NULL)
267
    return false;
268
  return object_merge_map->get_output_offset(this, shndx, offset,
269
                                             output_offset);
270
}
271
 
272
// Return whether this is the merge section for SHNDX in OBJECT.
273
 
274
bool
275
Merge_map::is_merge_section_for(const Relobj* object, unsigned int shndx) const
276
{
277
  Object_merge_map* object_merge_map = object->merge_map();
278
  if (object_merge_map == NULL)
279
    return false;
280
  return object_merge_map->is_merge_section_for(this, shndx);
281
}
282
 
283
// Class Output_merge_base.
284
 
285
// Return the output offset for an input offset.  The input address is
286
// at offset OFFSET in section SHNDX in OBJECT.  If we know the
287
// offset, set *POUTPUT and return true.  Otherwise return false.
288
 
289
bool
290
Output_merge_base::do_output_offset(const Relobj* object,
291
                                    unsigned int shndx,
292
                                    section_offset_type offset,
293
                                    section_offset_type* poutput) const
294
{
295
  return this->merge_map_.get_output_offset(object, shndx, offset, poutput);
296
}
297
 
298
// Return whether this is the merge section for SHNDX in OBJECT.
299
 
300
bool
301
Output_merge_base::do_is_merge_section_for(const Relobj* object,
302
                                           unsigned int shndx) const
303
{
304
  return this->merge_map_.is_merge_section_for(object, shndx);
305
}
306
 
307
// Class Output_merge_data.
308
 
309
// Compute the hash code for a fixed-size constant.
310
 
311
size_t
312
Output_merge_data::Merge_data_hash::operator()(Merge_data_key k) const
313
{
314
  const unsigned char* p = this->pomd_->constant(k);
315
  section_size_type entsize =
316
    convert_to_section_size_type(this->pomd_->entsize());
317
 
318
  // Fowler/Noll/Vo (FNV) hash (type FNV-1a).
319
  if (sizeof(size_t) == 8)
320
    {
321
      size_t result = static_cast<size_t>(14695981039346656037ULL);
322
      for (section_size_type i = 0; i < entsize; ++i)
323
        {
324
          result &= (size_t) *p++;
325
          result *= 1099511628211ULL;
326
        }
327
      return result;
328
    }
329
  else
330
    {
331
      size_t result = 2166136261UL;
332
      for (section_size_type i = 0; i < entsize; ++i)
333
        {
334
          result ^= (size_t) *p++;
335
          result *= 16777619UL;
336
        }
337
      return result;
338
    }
339
}
340
 
341
// Return whether one hash table key equals another.
342
 
343
bool
344
Output_merge_data::Merge_data_eq::operator()(Merge_data_key k1,
345
                                             Merge_data_key k2) const
346
{
347
  const unsigned char* p1 = this->pomd_->constant(k1);
348
  const unsigned char* p2 = this->pomd_->constant(k2);
349
  return memcmp(p1, p2, this->pomd_->entsize()) == 0;
350
}
351
 
352
// Add a constant to the end of the section contents.
353
 
354
void
355
Output_merge_data::add_constant(const unsigned char* p)
356
{
357
  section_size_type entsize = convert_to_section_size_type(this->entsize());
358
  section_size_type addralign =
359
    convert_to_section_size_type(this->addralign());
360
  section_size_type addsize = std::max(entsize, addralign);
361
  if (this->len_ + addsize > this->alc_)
362
    {
363
      if (this->alc_ == 0)
364
        this->alc_ = 128 * addsize;
365
      else
366
        this->alc_ *= 2;
367
      this->p_ = static_cast<unsigned char*>(realloc(this->p_, this->alc_));
368
      if (this->p_ == NULL)
369
        gold_nomem();
370
    }
371
 
372
  memcpy(this->p_ + this->len_, p, entsize);
373
  if (addsize > entsize)
374
    memset(this->p_ + this->len_ + entsize, 0, addsize - entsize);
375
  this->len_ += addsize;
376
}
377
 
378
// Add the input section SHNDX in OBJECT to a merged output section
379
// which holds fixed length constants.  Return whether we were able to
380
// handle the section; if not, it will be linked as usual without
381
// constant merging.
382
 
383
bool
384
Output_merge_data::do_add_input_section(Relobj* object, unsigned int shndx)
385
{
386
  section_size_type len;
387
  const unsigned char* p = object->section_contents(shndx, &len, false);
388
 
389
  section_size_type entsize = convert_to_section_size_type(this->entsize());
390
 
391
  if (len % entsize != 0)
392
    return false;
393
 
394
  this->input_count_ += len / entsize;
395
 
396
  for (section_size_type i = 0; i < len; i += entsize, p += entsize)
397
    {
398
      // Add the constant to the section contents.  If we find that it
399
      // is already in the hash table, we will remove it again.
400
      Merge_data_key k = this->len_;
401
      this->add_constant(p);
402
 
403
      std::pair<Merge_data_hashtable::iterator, bool> ins =
404
        this->hashtable_.insert(k);
405
 
406
      if (!ins.second)
407
        {
408
          // Key was already present.  Remove the copy we just added.
409
          this->len_ -= entsize;
410
          k = *ins.first;
411
        }
412
 
413
      // Record the offset of this constant in the output section.
414
      this->add_mapping(object, shndx, i, entsize, k);
415
    }
416
 
417
  return true;
418
}
419
 
420
// Set the final data size in a merged output section with fixed size
421
// constants.
422
 
423
void
424
Output_merge_data::set_final_data_size()
425
{
426
  // Release the memory we don't need.
427
  this->p_ = static_cast<unsigned char*>(realloc(this->p_, this->len_));
428
  gold_assert(this->p_ != NULL);
429
  this->set_data_size(this->len_);
430
}
431
 
432
// Write the data of a merged output section with fixed size constants
433
// to the file.
434
 
435
void
436
Output_merge_data::do_write(Output_file* of)
437
{
438
  of->write(this->offset(), this->p_, this->len_);
439
}
440
 
441
// Write the data to a buffer.
442
 
443
void
444
Output_merge_data::do_write_to_buffer(unsigned char* buffer)
445
{
446
  memcpy(buffer, this->p_, this->len_);
447
}
448
 
449
// Print merge stats to stderr.
450
 
451
void
452
Output_merge_data::do_print_merge_stats(const char* section_name)
453
{
454
  fprintf(stderr,
455
          _("%s: %s merged constants size: %lu; input: %zu; output: %zu\n"),
456
          program_name, section_name,
457
          static_cast<unsigned long>(this->entsize()),
458
          this->input_count_, this->hashtable_.size());
459
}
460
 
461
// Class Output_merge_string.
462
 
463
// Add an input section to a merged string section.
464
 
465
template<typename Char_type>
466
bool
467
Output_merge_string<Char_type>::do_add_input_section(Relobj* object,
468
                                                     unsigned int shndx)
469
{
470
  section_size_type len;
471
  const unsigned char* pdata = object->section_contents(shndx, &len, false);
472
 
473
  const Char_type* p = reinterpret_cast<const Char_type*>(pdata);
474
  const Char_type* pend = p + len / sizeof(Char_type);
475
 
476
  if (len % sizeof(Char_type) != 0)
477
    {
478
      object->error(_("mergeable string section length not multiple of "
479
                      "character size"));
480
      return false;
481
    }
482
 
483
  size_t count = 0;
484
 
485
  // The index I is in bytes, not characters.
486
  section_size_type i = 0;
487
  while (i < len)
488
    {
489
      const Char_type* pl;
490
      for (pl = p; *pl != 0; ++pl)
491
        {
492
          if (pl >= pend)
493
            {
494
              gold_warning(_("%s: last entry in mergeable string section '%s' "
495
                             "not null terminated"),
496
                           object->name().c_str(),
497
                           object->section_name(shndx).c_str());
498
              break;
499
            }
500
        }
501
 
502
      Stringpool::Key key;
503
      const Char_type* str = this->stringpool_.add_with_length(p, pl - p, true,
504
                                                               &key);
505
 
506
      section_size_type bytelen_with_null = ((pl - p) + 1) * sizeof(Char_type);
507
      this->merged_strings_.push_back(Merged_string(object, shndx, i, str,
508
                                                    bytelen_with_null, key));
509
 
510
      p = pl + 1;
511
      i += bytelen_with_null;
512
      ++count;
513
    }
514
 
515
  this->input_count_ += count;
516
 
517
  return true;
518
}
519
 
520
// Finalize the mappings from the input sections to the output
521
// section, and return the final data size.
522
 
523
template<typename Char_type>
524
section_size_type
525
Output_merge_string<Char_type>::finalize_merged_data()
526
{
527
  this->stringpool_.set_string_offsets();
528
 
529
  for (typename Merged_strings::const_iterator p =
530
         this->merged_strings_.begin();
531
       p != this->merged_strings_.end();
532
       ++p)
533
    {
534
      section_offset_type offset =
535
        this->stringpool_.get_offset_from_key(p->stringpool_key);
536
      this->add_mapping(p->object, p->shndx, p->offset, p->length, offset);
537
    }
538
 
539
  // Save some memory.  This also ensures that this function will work
540
  // if called twice, as may happen if Layout::set_segment_offsets
541
  // finds a better alignment.
542
  this->merged_strings_.clear();
543
 
544
  return this->stringpool_.get_strtab_size();
545
}
546
 
547
template<typename Char_type>
548
void
549
Output_merge_string<Char_type>::set_final_data_size()
550
{
551
  const off_t final_data_size = this->finalize_merged_data();
552
  this->set_data_size(final_data_size);
553
}
554
 
555
// Write out a merged string section.
556
 
557
template<typename Char_type>
558
void
559
Output_merge_string<Char_type>::do_write(Output_file* of)
560
{
561
  this->stringpool_.write(of, this->offset());
562
}
563
 
564
// Write a merged string section to a buffer.
565
 
566
template<typename Char_type>
567
void
568
Output_merge_string<Char_type>::do_write_to_buffer(unsigned char* buffer)
569
{
570
  this->stringpool_.write_to_buffer(buffer, this->data_size());
571
}
572
 
573
// Return the name of the types of string to use with
574
// do_print_merge_stats.
575
 
576
template<typename Char_type>
577
const char*
578
Output_merge_string<Char_type>::string_name()
579
{
580
  gold_unreachable();
581
  return NULL;
582
}
583
 
584
template<>
585
const char*
586
Output_merge_string<char>::string_name()
587
{
588
  return "strings";
589
}
590
 
591
template<>
592
const char*
593
Output_merge_string<uint16_t>::string_name()
594
{
595
  return "16-bit strings";
596
}
597
 
598
template<>
599
const char*
600
Output_merge_string<uint32_t>::string_name()
601
{
602
  return "32-bit strings";
603
}
604
 
605
// Print merge stats to stderr.
606
 
607
template<typename Char_type>
608
void
609
Output_merge_string<Char_type>::do_print_merge_stats(const char* section_name)
610
{
611
  char buf[200];
612
  snprintf(buf, sizeof buf, "%s merged %s", section_name, this->string_name());
613
  fprintf(stderr, _("%s: %s input: %zu\n"),
614
          program_name, buf, this->input_count_);
615
  this->stringpool_.print_stats(buf);
616
}
617
 
618
// Instantiate the templates we need.
619
 
620
template
621
class Output_merge_string<char>;
622
 
623
template
624
class Output_merge_string<uint16_t>;
625
 
626
template
627
class Output_merge_string<uint32_t>;
628
 
629
#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
630
template
631
void
632
Object_merge_map::initialize_input_to_output_map<32>(
633
    unsigned int shndx,
634
    elfcpp::Elf_types<32>::Elf_Addr starting_address,
635
    Unordered_map<section_offset_type, elfcpp::Elf_types<32>::Elf_Addr>*);
636
#endif
637
 
638
#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
639
template
640
void
641
Object_merge_map::initialize_input_to_output_map<64>(
642
    unsigned int shndx,
643
    elfcpp::Elf_types<64>::Elf_Addr starting_address,
644
    Unordered_map<section_offset_type, elfcpp::Elf_types<64>::Elf_Addr>*);
645
#endif
646
 
647
} // End namespace gold.

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