* layout.cc (Free_list::allocate): Provide guarantee of minimum
[external/binutils.git] / gold / layout.cc
1 // layout.cc -- lay out output file sections for gold
2
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 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 <cerrno>
26 #include <cstring>
27 #include <algorithm>
28 #include <iostream>
29 #include <fstream>
30 #include <utility>
31 #include <fcntl.h>
32 #include <fnmatch.h>
33 #include <unistd.h>
34 #include "libiberty.h"
35 #include "md5.h"
36 #include "sha1.h"
37
38 #include "parameters.h"
39 #include "options.h"
40 #include "mapfile.h"
41 #include "script.h"
42 #include "script-sections.h"
43 #include "output.h"
44 #include "symtab.h"
45 #include "dynobj.h"
46 #include "ehframe.h"
47 #include "compressed_output.h"
48 #include "reduced_debug_output.h"
49 #include "object.h"
50 #include "reloc.h"
51 #include "descriptors.h"
52 #include "plugin.h"
53 #include "incremental.h"
54 #include "layout.h"
55
56 namespace gold
57 {
58
59 // Class Free_list.
60
61 // The total number of free lists used.
62 unsigned int Free_list::num_lists = 0;
63 // The total number of free list nodes used.
64 unsigned int Free_list::num_nodes = 0;
65 // The total number of calls to Free_list::remove.
66 unsigned int Free_list::num_removes = 0;
67 // The total number of nodes visited during calls to Free_list::remove.
68 unsigned int Free_list::num_remove_visits = 0;
69 // The total number of calls to Free_list::allocate.
70 unsigned int Free_list::num_allocates = 0;
71 // The total number of nodes visited during calls to Free_list::allocate.
72 unsigned int Free_list::num_allocate_visits = 0;
73
74 // Initialize the free list.  Creates a single free list node that
75 // describes the entire region of length LEN.  If EXTEND is true,
76 // allocate() is allowed to extend the region beyond its initial
77 // length.
78
79 void
80 Free_list::init(off_t len, bool extend)
81 {
82   this->list_.push_front(Free_list_node(0, len));
83   this->last_remove_ = this->list_.begin();
84   this->extend_ = extend;
85   this->length_ = len;
86   ++Free_list::num_lists;
87   ++Free_list::num_nodes;
88 }
89
90 // Remove a chunk from the free list.  Because we start with a single
91 // node that covers the entire section, and remove chunks from it one
92 // at a time, we do not need to coalesce chunks or handle cases that
93 // span more than one free node.  We expect to remove chunks from the
94 // free list in order, and we expect to have only a few chunks of free
95 // space left (corresponding to files that have changed since the last
96 // incremental link), so a simple linear list should provide sufficient
97 // performance.
98
99 void
100 Free_list::remove(off_t start, off_t end)
101 {
102   if (start == end)
103     return;
104   gold_assert(start < end);
105
106   ++Free_list::num_removes;
107
108   Iterator p = this->last_remove_;
109   if (p->start_ > start)
110     p = this->list_.begin();
111
112   for (; p != this->list_.end(); ++p)
113     {
114       ++Free_list::num_remove_visits;
115       // Find a node that wholly contains the indicated region.
116       if (p->start_ <= start && p->end_ >= end)
117         {
118           // Case 1: the indicated region spans the whole node.
119           // Add some fuzz to avoid creating tiny free chunks.
120           if (p->start_ + 3 >= start && p->end_ <= end + 3)
121             p = this->list_.erase(p);
122           // Case 2: remove a chunk from the start of the node.
123           else if (p->start_ + 3 >= start)
124             p->start_ = end;
125           // Case 3: remove a chunk from the end of the node.
126           else if (p->end_ <= end + 3)
127             p->end_ = start;
128           // Case 4: remove a chunk from the middle, and split
129           // the node into two.
130           else
131             {
132               Free_list_node newnode(p->start_, start);
133               p->start_ = end;
134               this->list_.insert(p, newnode);
135               ++Free_list::num_nodes;
136             }
137           this->last_remove_ = p;
138           return;
139         }
140     }
141
142   // Did not find a node containing the given chunk.  This could happen
143   // because a small chunk was already removed due to the fuzz.
144   gold_debug(DEBUG_INCREMENTAL,
145              "Free_list::remove(%d,%d) not found",
146              static_cast<int>(start), static_cast<int>(end));
147 }
148
149 // Allocate a chunk of size LEN from the free list.  Returns -1ULL
150 // if a sufficiently large chunk of free space is not found.
151 // We use a simple first-fit algorithm.
152
153 off_t
154 Free_list::allocate(off_t len, uint64_t align, off_t minoff)
155 {
156   gold_debug(DEBUG_INCREMENTAL,
157              "Free_list::allocate(%08lx, %d, %08lx)",
158              static_cast<long>(len), static_cast<int>(align),
159              static_cast<long>(minoff));
160   if (len == 0)
161     return align_address(minoff, align);
162
163   ++Free_list::num_allocates;
164
165   // We usually want to drop free chunks smaller than 4 bytes.
166   // If we need to guarantee a minimum hole size, though, we need
167   // to keep track of all free chunks.
168   const int fuzz = this->min_hole_ > 0 ? 0 : 3;
169
170   for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
171     {
172       ++Free_list::num_allocate_visits;
173       off_t start = p->start_ > minoff ? p->start_ : minoff;
174       start = align_address(start, align);
175       off_t end = start + len;
176       if (end > p->end_ && p->end_ == this->length_ && this->extend_)
177         {
178           this->length_ = end;
179           p->end_ = end;
180         }
181       if (end == p->end_ || (end <= p->end_ - this->min_hole_))
182         {
183           if (p->start_ + fuzz >= start && p->end_ <= end + fuzz)
184             this->list_.erase(p);
185           else if (p->start_ + fuzz >= start)
186             p->start_ = end;
187           else if (p->end_ <= end + fuzz)
188             p->end_ = start;
189           else
190             {
191               Free_list_node newnode(p->start_, start);
192               p->start_ = end;
193               this->list_.insert(p, newnode);
194               ++Free_list::num_nodes;
195             }
196           return start;
197         }
198     }
199   if (this->extend_)
200     {
201       off_t start = align_address(this->length_, align);
202       this->length_ = start + len;
203       return start;
204     }
205   return -1;
206 }
207
208 // Dump the free list (for debugging).
209 void
210 Free_list::dump()
211 {
212   gold_info("Free list:\n     start      end   length\n");
213   for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
214     gold_info("  %08lx %08lx %08lx", static_cast<long>(p->start_),
215               static_cast<long>(p->end_),
216               static_cast<long>(p->end_ - p->start_));
217 }
218
219 // Print the statistics for the free lists.
220 void
221 Free_list::print_stats()
222 {
223   fprintf(stderr, _("%s: total free lists: %u\n"),
224           program_name, Free_list::num_lists);
225   fprintf(stderr, _("%s: total free list nodes: %u\n"),
226           program_name, Free_list::num_nodes);
227   fprintf(stderr, _("%s: calls to Free_list::remove: %u\n"),
228           program_name, Free_list::num_removes);
229   fprintf(stderr, _("%s: nodes visited: %u\n"),
230           program_name, Free_list::num_remove_visits);
231   fprintf(stderr, _("%s: calls to Free_list::allocate: %u\n"),
232           program_name, Free_list::num_allocates);
233   fprintf(stderr, _("%s: nodes visited: %u\n"),
234           program_name, Free_list::num_allocate_visits);
235 }
236
237 // Layout::Relaxation_debug_check methods.
238
239 // Check that sections and special data are in reset states.
240 // We do not save states for Output_sections and special Output_data.
241 // So we check that they have not assigned any addresses or offsets.
242 // clean_up_after_relaxation simply resets their addresses and offsets.
243 void
244 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
245     const Layout::Section_list& sections,
246     const Layout::Data_list& special_outputs)
247 {
248   for(Layout::Section_list::const_iterator p = sections.begin();
249       p != sections.end();
250       ++p)
251     gold_assert((*p)->address_and_file_offset_have_reset_values());
252
253   for(Layout::Data_list::const_iterator p = special_outputs.begin();
254       p != special_outputs.end();
255       ++p)
256     gold_assert((*p)->address_and_file_offset_have_reset_values());
257 }
258   
259 // Save information of SECTIONS for checking later.
260
261 void
262 Layout::Relaxation_debug_check::read_sections(
263     const Layout::Section_list& sections)
264 {
265   for(Layout::Section_list::const_iterator p = sections.begin();
266       p != sections.end();
267       ++p)
268     {
269       Output_section* os = *p;
270       Section_info info;
271       info.output_section = os;
272       info.address = os->is_address_valid() ? os->address() : 0;
273       info.data_size = os->is_data_size_valid() ? os->data_size() : -1;
274       info.offset = os->is_offset_valid()? os->offset() : -1 ;
275       this->section_infos_.push_back(info);
276     }
277 }
278
279 // Verify SECTIONS using previously recorded information.
280
281 void
282 Layout::Relaxation_debug_check::verify_sections(
283     const Layout::Section_list& sections)
284 {
285   size_t i = 0;
286   for(Layout::Section_list::const_iterator p = sections.begin();
287       p != sections.end();
288       ++p, ++i)
289     {
290       Output_section* os = *p;
291       uint64_t address = os->is_address_valid() ? os->address() : 0;
292       off_t data_size = os->is_data_size_valid() ? os->data_size() : -1;
293       off_t offset = os->is_offset_valid()? os->offset() : -1 ;
294
295       if (i >= this->section_infos_.size())
296         {
297           gold_fatal("Section_info of %s missing.\n", os->name());
298         }
299       const Section_info& info = this->section_infos_[i];
300       if (os != info.output_section)
301         gold_fatal("Section order changed.  Expecting %s but see %s\n",
302                    info.output_section->name(), os->name());
303       if (address != info.address
304           || data_size != info.data_size
305           || offset != info.offset)
306         gold_fatal("Section %s changed.\n", os->name());
307     }
308 }
309
310 // Layout_task_runner methods.
311
312 // Lay out the sections.  This is called after all the input objects
313 // have been read.
314
315 void
316 Layout_task_runner::run(Workqueue* workqueue, const Task* task)
317 {
318   Layout* layout = this->layout_;
319   off_t file_size = layout->finalize(this->input_objects_,
320                                      this->symtab_,
321                                      this->target_,
322                                      task);
323
324   // Now we know the final size of the output file and we know where
325   // each piece of information goes.
326
327   if (this->mapfile_ != NULL)
328     {
329       this->mapfile_->print_discarded_sections(this->input_objects_);
330       layout->print_to_mapfile(this->mapfile_);
331     }
332
333   Output_file* of;
334   if (layout->incremental_base() == NULL)
335     {
336       of = new Output_file(parameters->options().output_file_name());
337       if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
338         of->set_is_temporary();
339       of->open(file_size);
340     }
341   else
342     {
343       of = layout->incremental_base()->output_file();
344
345       // Apply the incremental relocations for symbols whose values
346       // have changed.  We do this before we resize the file and start
347       // writing anything else to it, so that we can read the old
348       // incremental information from the file before (possibly)
349       // overwriting it.
350       if (parameters->incremental_update())
351         layout->incremental_base()->apply_incremental_relocs(this->symtab_,
352                                                              this->layout_,
353                                                              of);
354
355       of->resize(file_size);
356     }
357
358   // Queue up the final set of tasks.
359   gold::queue_final_tasks(this->options_, this->input_objects_,
360                           this->symtab_, layout, workqueue, of);
361 }
362
363 // Layout methods.
364
365 Layout::Layout(int number_of_input_files, Script_options* script_options)
366   : number_of_input_files_(number_of_input_files),
367     script_options_(script_options),
368     namepool_(),
369     sympool_(),
370     dynpool_(),
371     signatures_(),
372     section_name_map_(),
373     segment_list_(),
374     section_list_(),
375     unattached_section_list_(),
376     special_output_list_(),
377     section_headers_(NULL),
378     tls_segment_(NULL),
379     relro_segment_(NULL),
380     interp_segment_(NULL),
381     increase_relro_(0),
382     symtab_section_(NULL),
383     symtab_xindex_(NULL),
384     dynsym_section_(NULL),
385     dynsym_xindex_(NULL),
386     dynamic_section_(NULL),
387     dynamic_symbol_(NULL),
388     dynamic_data_(NULL),
389     eh_frame_section_(NULL),
390     eh_frame_data_(NULL),
391     added_eh_frame_data_(false),
392     eh_frame_hdr_section_(NULL),
393     build_id_note_(NULL),
394     debug_abbrev_(NULL),
395     debug_info_(NULL),
396     group_signatures_(),
397     output_file_size_(-1),
398     have_added_input_section_(false),
399     sections_are_attached_(false),
400     input_requires_executable_stack_(false),
401     input_with_gnu_stack_note_(false),
402     input_without_gnu_stack_note_(false),
403     has_static_tls_(false),
404     any_postprocessing_sections_(false),
405     resized_signatures_(false),
406     have_stabstr_section_(false),
407     section_ordering_specified_(false),
408     incremental_inputs_(NULL),
409     record_output_section_data_from_script_(false),
410     script_output_section_data_list_(),
411     segment_states_(NULL),
412     relaxation_debug_check_(NULL),
413     input_section_position_(),
414     input_section_glob_(),
415     incremental_base_(NULL),
416     free_list_()
417 {
418   // Make space for more than enough segments for a typical file.
419   // This is just for efficiency--it's OK if we wind up needing more.
420   this->segment_list_.reserve(12);
421
422   // We expect two unattached Output_data objects: the file header and
423   // the segment headers.
424   this->special_output_list_.reserve(2);
425
426   // Initialize structure needed for an incremental build.
427   if (parameters->incremental())
428     this->incremental_inputs_ = new Incremental_inputs;
429
430   // The section name pool is worth optimizing in all cases, because
431   // it is small, but there are often overlaps due to .rel sections.
432   this->namepool_.set_optimize();
433 }
434
435 // For incremental links, record the base file to be modified.
436
437 void
438 Layout::set_incremental_base(Incremental_binary* base)
439 {
440   this->incremental_base_ = base;
441   this->free_list_.init(base->output_file()->filesize(), true);
442 }
443
444 // Hash a key we use to look up an output section mapping.
445
446 size_t
447 Layout::Hash_key::operator()(const Layout::Key& k) const
448 {
449  return k.first + k.second.first + k.second.second;
450 }
451
452 // Returns whether the given section is in the list of
453 // debug-sections-used-by-some-version-of-gdb.  Currently,
454 // we've checked versions of gdb up to and including 6.7.1.
455
456 static const char* gdb_sections[] =
457 { ".debug_abbrev",
458   // ".debug_aranges",   // not used by gdb as of 6.7.1
459   ".debug_frame",
460   ".debug_info",
461   ".debug_types",
462   ".debug_line",
463   ".debug_loc",
464   ".debug_macinfo",
465   // ".debug_pubnames",  // not used by gdb as of 6.7.1
466   ".debug_ranges",
467   ".debug_str",
468 };
469
470 static const char* lines_only_debug_sections[] =
471 { ".debug_abbrev",
472   // ".debug_aranges",   // not used by gdb as of 6.7.1
473   // ".debug_frame",
474   ".debug_info",
475   // ".debug_types",
476   ".debug_line",
477   // ".debug_loc",
478   // ".debug_macinfo",
479   // ".debug_pubnames",  // not used by gdb as of 6.7.1
480   // ".debug_ranges",
481   ".debug_str",
482 };
483
484 static inline bool
485 is_gdb_debug_section(const char* str)
486 {
487   // We can do this faster: binary search or a hashtable.  But why bother?
488   for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
489     if (strcmp(str, gdb_sections[i]) == 0)
490       return true;
491   return false;
492 }
493
494 static inline bool
495 is_lines_only_debug_section(const char* str)
496 {
497   // We can do this faster: binary search or a hashtable.  But why bother?
498   for (size_t i = 0;
499        i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections);
500        ++i)
501     if (strcmp(str, lines_only_debug_sections[i]) == 0)
502       return true;
503   return false;
504 }
505
506 // Sometimes we compress sections.  This is typically done for
507 // sections that are not part of normal program execution (such as
508 // .debug_* sections), and where the readers of these sections know
509 // how to deal with compressed sections.  This routine doesn't say for
510 // certain whether we'll compress -- it depends on commandline options
511 // as well -- just whether this section is a candidate for compression.
512 // (The Output_compressed_section class decides whether to compress
513 // a given section, and picks the name of the compressed section.)
514
515 static bool
516 is_compressible_debug_section(const char* secname)
517 {
518   return (is_prefix_of(".debug", secname));
519 }
520
521 // We may see compressed debug sections in input files.  Return TRUE
522 // if this is the name of a compressed debug section.
523
524 bool
525 is_compressed_debug_section(const char* secname)
526 {
527   return (is_prefix_of(".zdebug", secname));
528 }
529
530 // Whether to include this section in the link.
531
532 template<int size, bool big_endian>
533 bool
534 Layout::include_section(Sized_relobj_file<size, big_endian>*, const char* name,
535                         const elfcpp::Shdr<size, big_endian>& shdr)
536 {
537   if (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE)
538     return false;
539
540   switch (shdr.get_sh_type())
541     {
542     case elfcpp::SHT_NULL:
543     case elfcpp::SHT_SYMTAB:
544     case elfcpp::SHT_DYNSYM:
545     case elfcpp::SHT_HASH:
546     case elfcpp::SHT_DYNAMIC:
547     case elfcpp::SHT_SYMTAB_SHNDX:
548       return false;
549
550     case elfcpp::SHT_STRTAB:
551       // Discard the sections which have special meanings in the ELF
552       // ABI.  Keep others (e.g., .stabstr).  We could also do this by
553       // checking the sh_link fields of the appropriate sections.
554       return (strcmp(name, ".dynstr") != 0
555               && strcmp(name, ".strtab") != 0
556               && strcmp(name, ".shstrtab") != 0);
557
558     case elfcpp::SHT_RELA:
559     case elfcpp::SHT_REL:
560     case elfcpp::SHT_GROUP:
561       // If we are emitting relocations these should be handled
562       // elsewhere.
563       gold_assert(!parameters->options().relocatable()
564                   && !parameters->options().emit_relocs());
565       return false;
566
567     case elfcpp::SHT_PROGBITS:
568       if (parameters->options().strip_debug()
569           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
570         {
571           if (is_debug_info_section(name))
572             return false;
573         }
574       if (parameters->options().strip_debug_non_line()
575           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
576         {
577           // Debugging sections can only be recognized by name.
578           if (is_prefix_of(".debug", name)
579               && !is_lines_only_debug_section(name))
580             return false;
581         }
582       if (parameters->options().strip_debug_gdb()
583           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
584         {
585           // Debugging sections can only be recognized by name.
586           if (is_prefix_of(".debug", name)
587               && !is_gdb_debug_section(name))
588             return false;
589         }
590       if (parameters->options().strip_lto_sections()
591           && !parameters->options().relocatable()
592           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
593         {
594           // Ignore LTO sections containing intermediate code.
595           if (is_prefix_of(".gnu.lto_", name))
596             return false;
597         }
598       // The GNU linker strips .gnu_debuglink sections, so we do too.
599       // This is a feature used to keep debugging information in
600       // separate files.
601       if (strcmp(name, ".gnu_debuglink") == 0)
602         return false;
603       return true;
604
605     default:
606       return true;
607     }
608 }
609
610 // Return an output section named NAME, or NULL if there is none.
611
612 Output_section*
613 Layout::find_output_section(const char* name) const
614 {
615   for (Section_list::const_iterator p = this->section_list_.begin();
616        p != this->section_list_.end();
617        ++p)
618     if (strcmp((*p)->name(), name) == 0)
619       return *p;
620   return NULL;
621 }
622
623 // Return an output segment of type TYPE, with segment flags SET set
624 // and segment flags CLEAR clear.  Return NULL if there is none.
625
626 Output_segment*
627 Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
628                             elfcpp::Elf_Word clear) const
629 {
630   for (Segment_list::const_iterator p = this->segment_list_.begin();
631        p != this->segment_list_.end();
632        ++p)
633     if (static_cast<elfcpp::PT>((*p)->type()) == type
634         && ((*p)->flags() & set) == set
635         && ((*p)->flags() & clear) == 0)
636       return *p;
637   return NULL;
638 }
639
640 // When we put a .ctors or .dtors section with more than one word into
641 // a .init_array or .fini_array section, we need to reverse the words
642 // in the .ctors/.dtors section.  This is because .init_array executes
643 // constructors front to back, where .ctors executes them back to
644 // front, and vice-versa for .fini_array/.dtors.  Although we do want
645 // to remap .ctors/.dtors into .init_array/.fini_array because it can
646 // be more efficient, we don't want to change the order in which
647 // constructors/destructors are run.  This set just keeps track of
648 // these sections which need to be reversed.  It is only changed by
649 // Layout::layout.  It should be a private member of Layout, but that
650 // would require layout.h to #include object.h to get the definition
651 // of Section_id.
652 static Unordered_set<Section_id, Section_id_hash> ctors_sections_in_init_array;
653
654 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a
655 // .init_array/.fini_array section.
656
657 bool
658 Layout::is_ctors_in_init_array(Relobj* relobj, unsigned int shndx) const
659 {
660   return (ctors_sections_in_init_array.find(Section_id(relobj, shndx))
661           != ctors_sections_in_init_array.end());
662 }
663
664 // Return the output section to use for section NAME with type TYPE
665 // and section flags FLAGS.  NAME must be canonicalized in the string
666 // pool, and NAME_KEY is the key.  ORDER is where this should appear
667 // in the output sections.  IS_RELRO is true for a relro section.
668
669 Output_section*
670 Layout::get_output_section(const char* name, Stringpool::Key name_key,
671                            elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
672                            Output_section_order order, bool is_relro)
673 {
674   elfcpp::Elf_Word lookup_type = type;
675
676   // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and
677   // PREINIT_ARRAY like PROGBITS.  This ensures that we combine
678   // .init_array, .fini_array, and .preinit_array sections by name
679   // whatever their type in the input file.  We do this because the
680   // types are not always right in the input files.
681   if (lookup_type == elfcpp::SHT_INIT_ARRAY
682       || lookup_type == elfcpp::SHT_FINI_ARRAY
683       || lookup_type == elfcpp::SHT_PREINIT_ARRAY)
684     lookup_type = elfcpp::SHT_PROGBITS;
685
686   elfcpp::Elf_Xword lookup_flags = flags;
687
688   // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
689   // read-write with read-only sections.  Some other ELF linkers do
690   // not do this.  FIXME: Perhaps there should be an option
691   // controlling this.
692   lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
693
694   const Key key(name_key, std::make_pair(lookup_type, lookup_flags));
695   const std::pair<Key, Output_section*> v(key, NULL);
696   std::pair<Section_name_map::iterator, bool> ins(
697     this->section_name_map_.insert(v));
698
699   if (!ins.second)
700     return ins.first->second;
701   else
702     {
703       // This is the first time we've seen this name/type/flags
704       // combination.  For compatibility with the GNU linker, we
705       // combine sections with contents and zero flags with sections
706       // with non-zero flags.  This is a workaround for cases where
707       // assembler code forgets to set section flags.  FIXME: Perhaps
708       // there should be an option to control this.
709       Output_section* os = NULL;
710
711       if (lookup_type == elfcpp::SHT_PROGBITS)
712         {
713           if (flags == 0)
714             {
715               Output_section* same_name = this->find_output_section(name);
716               if (same_name != NULL
717                   && (same_name->type() == elfcpp::SHT_PROGBITS
718                       || same_name->type() == elfcpp::SHT_INIT_ARRAY
719                       || same_name->type() == elfcpp::SHT_FINI_ARRAY
720                       || same_name->type() == elfcpp::SHT_PREINIT_ARRAY)
721                   && (same_name->flags() & elfcpp::SHF_TLS) == 0)
722                 os = same_name;
723             }
724           else if ((flags & elfcpp::SHF_TLS) == 0)
725             {
726               elfcpp::Elf_Xword zero_flags = 0;
727               const Key zero_key(name_key, std::make_pair(lookup_type,
728                                                           zero_flags));
729               Section_name_map::iterator p =
730                   this->section_name_map_.find(zero_key);
731               if (p != this->section_name_map_.end())
732                 os = p->second;
733             }
734         }
735
736       if (os == NULL)
737         os = this->make_output_section(name, type, flags, order, is_relro);
738
739       ins.first->second = os;
740       return os;
741     }
742 }
743
744 // Pick the output section to use for section NAME, in input file
745 // RELOBJ, with type TYPE and flags FLAGS.  RELOBJ may be NULL for a
746 // linker created section.  IS_INPUT_SECTION is true if we are
747 // choosing an output section for an input section found in a input
748 // file.  ORDER is where this section should appear in the output
749 // sections.  IS_RELRO is true for a relro section.  This will return
750 // NULL if the input section should be discarded.
751
752 Output_section*
753 Layout::choose_output_section(const Relobj* relobj, const char* name,
754                               elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
755                               bool is_input_section, Output_section_order order,
756                               bool is_relro)
757 {
758   // We should not see any input sections after we have attached
759   // sections to segments.
760   gold_assert(!is_input_section || !this->sections_are_attached_);
761
762   // Some flags in the input section should not be automatically
763   // copied to the output section.
764   flags &= ~ (elfcpp::SHF_INFO_LINK
765               | elfcpp::SHF_GROUP
766               | elfcpp::SHF_MERGE
767               | elfcpp::SHF_STRINGS);
768
769   // We only clear the SHF_LINK_ORDER flag in for
770   // a non-relocatable link.
771   if (!parameters->options().relocatable())
772     flags &= ~elfcpp::SHF_LINK_ORDER;
773
774   if (this->script_options_->saw_sections_clause())
775     {
776       // We are using a SECTIONS clause, so the output section is
777       // chosen based only on the name.
778
779       Script_sections* ss = this->script_options_->script_sections();
780       const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
781       Output_section** output_section_slot;
782       Script_sections::Section_type script_section_type;
783       const char* orig_name = name;
784       name = ss->output_section_name(file_name, name, &output_section_slot,
785                                      &script_section_type);
786       if (name == NULL)
787         {
788           gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' "
789                                      "because it is not allowed by the "
790                                      "SECTIONS clause of the linker script"),
791                      orig_name);
792           // The SECTIONS clause says to discard this input section.
793           return NULL;
794         }
795
796       // We can only handle script section types ST_NONE and ST_NOLOAD.
797       switch (script_section_type)
798         {
799         case Script_sections::ST_NONE:
800           break;
801         case Script_sections::ST_NOLOAD:
802           flags &= elfcpp::SHF_ALLOC;
803           break;
804         default:
805           gold_unreachable();
806         }
807
808       // If this is an orphan section--one not mentioned in the linker
809       // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
810       // default processing below.
811
812       if (output_section_slot != NULL)
813         {
814           if (*output_section_slot != NULL)
815             {
816               (*output_section_slot)->update_flags_for_input_section(flags);
817               return *output_section_slot;
818             }
819
820           // We don't put sections found in the linker script into
821           // SECTION_NAME_MAP_.  That keeps us from getting confused
822           // if an orphan section is mapped to a section with the same
823           // name as one in the linker script.
824
825           name = this->namepool_.add(name, false, NULL);
826
827           Output_section* os = this->make_output_section(name, type, flags,
828                                                          order, is_relro);
829
830           os->set_found_in_sections_clause();
831
832           // Special handling for NOLOAD sections.
833           if (script_section_type == Script_sections::ST_NOLOAD)
834             {
835               os->set_is_noload();
836
837               // The constructor of Output_section sets addresses of non-ALLOC
838               // sections to 0 by default.  We don't want that for NOLOAD
839               // sections even if they have no SHF_ALLOC flag.
840               if ((os->flags() & elfcpp::SHF_ALLOC) == 0
841                   && os->is_address_valid())
842                 {
843                   gold_assert(os->address() == 0
844                               && !os->is_offset_valid()
845                               && !os->is_data_size_valid());
846                   os->reset_address_and_file_offset();
847                 }
848             }
849
850           *output_section_slot = os;
851           return os;
852         }
853     }
854
855   // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
856
857   size_t len = strlen(name);
858   char* uncompressed_name = NULL;
859
860   // Compressed debug sections should be mapped to the corresponding
861   // uncompressed section.
862   if (is_compressed_debug_section(name))
863     {
864       uncompressed_name = new char[len];
865       uncompressed_name[0] = '.';
866       gold_assert(name[0] == '.' && name[1] == 'z');
867       strncpy(&uncompressed_name[1], &name[2], len - 2);
868       uncompressed_name[len - 1] = '\0';
869       len -= 1;
870       name = uncompressed_name;
871     }
872
873   // Turn NAME from the name of the input section into the name of the
874   // output section.
875   if (is_input_section
876       && !this->script_options_->saw_sections_clause()
877       && !parameters->options().relocatable())
878     name = Layout::output_section_name(relobj, name, &len);
879
880   Stringpool::Key name_key;
881   name = this->namepool_.add_with_length(name, len, true, &name_key);
882
883   if (uncompressed_name != NULL)
884     delete[] uncompressed_name;
885
886   // Find or make the output section.  The output section is selected
887   // based on the section name, type, and flags.
888   return this->get_output_section(name, name_key, type, flags, order, is_relro);
889 }
890
891 // For incremental links, record the initial fixed layout of a section
892 // from the base file, and return a pointer to the Output_section.
893
894 template<int size, bool big_endian>
895 Output_section*
896 Layout::init_fixed_output_section(const char* name,
897                                   elfcpp::Shdr<size, big_endian>& shdr)
898 {
899   unsigned int sh_type = shdr.get_sh_type();
900
901   // We preserve the layout of PROGBITS, NOBITS, and NOTE sections.
902   // All others will be created from scratch and reallocated.
903   if (sh_type != elfcpp::SHT_PROGBITS
904       && sh_type != elfcpp::SHT_NOBITS
905       && sh_type != elfcpp::SHT_NOTE)
906     return NULL;
907
908   typename elfcpp::Elf_types<size>::Elf_Addr sh_addr = shdr.get_sh_addr();
909   typename elfcpp::Elf_types<size>::Elf_Off sh_offset = shdr.get_sh_offset();
910   typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
911   typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
912   typename elfcpp::Elf_types<size>::Elf_WXword sh_addralign =
913       shdr.get_sh_addralign();
914
915   // Make the output section.
916   Stringpool::Key name_key;
917   name = this->namepool_.add(name, true, &name_key);
918   Output_section* os = this->get_output_section(name, name_key, sh_type,
919                                                 sh_flags, ORDER_INVALID, false);
920   os->set_fixed_layout(sh_addr, sh_offset, sh_size, sh_addralign);
921   if (sh_type != elfcpp::SHT_NOBITS)
922     this->free_list_.remove(sh_offset, sh_offset + sh_size);
923   return os;
924 }
925
926 // Return the output section to use for input section SHNDX, with name
927 // NAME, with header HEADER, from object OBJECT.  RELOC_SHNDX is the
928 // index of a relocation section which applies to this section, or 0
929 // if none, or -1U if more than one.  RELOC_TYPE is the type of the
930 // relocation section if there is one.  Set *OFF to the offset of this
931 // input section without the output section.  Return NULL if the
932 // section should be discarded.  Set *OFF to -1 if the section
933 // contents should not be written directly to the output file, but
934 // will instead receive special handling.
935
936 template<int size, bool big_endian>
937 Output_section*
938 Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
939                const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
940                unsigned int reloc_shndx, unsigned int, off_t* off)
941 {
942   *off = 0;
943
944   if (!this->include_section(object, name, shdr))
945     return NULL;
946
947   elfcpp::Elf_Word sh_type = shdr.get_sh_type();
948
949   // In a relocatable link a grouped section must not be combined with
950   // any other sections.
951   Output_section* os;
952   if (parameters->options().relocatable()
953       && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
954     {
955       name = this->namepool_.add(name, true, NULL);
956       os = this->make_output_section(name, sh_type, shdr.get_sh_flags(),
957                                      ORDER_INVALID, false);
958     }
959   else
960     {
961       os = this->choose_output_section(object, name, sh_type,
962                                        shdr.get_sh_flags(), true,
963                                        ORDER_INVALID, false);
964       if (os == NULL)
965         return NULL;
966     }
967
968   // By default the GNU linker sorts input sections whose names match
969   // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*.  The
970   // sections are sorted by name.  This is used to implement
971   // constructor priority ordering.  We are compatible.  When we put
972   // .ctor sections in .init_array and .dtor sections in .fini_array,
973   // we must also sort plain .ctor and .dtor sections.
974   if (!this->script_options_->saw_sections_clause()
975       && !parameters->options().relocatable()
976       && (is_prefix_of(".ctors.", name)
977           || is_prefix_of(".dtors.", name)
978           || is_prefix_of(".init_array.", name)
979           || is_prefix_of(".fini_array.", name)
980           || (parameters->options().ctors_in_init_array()
981               && (strcmp(name, ".ctors") == 0
982                   || strcmp(name, ".dtors") == 0))))
983     os->set_must_sort_attached_input_sections();
984
985   // If this is a .ctors or .ctors.* section being mapped to a
986   // .init_array section, or a .dtors or .dtors.* section being mapped
987   // to a .fini_array section, we will need to reverse the words if
988   // there is more than one.  Record this section for later.  See
989   // ctors_sections_in_init_array above.
990   if (!this->script_options_->saw_sections_clause()
991       && !parameters->options().relocatable()
992       && shdr.get_sh_size() > size / 8
993       && (((strcmp(name, ".ctors") == 0
994             || is_prefix_of(".ctors.", name))
995            && strcmp(os->name(), ".init_array") == 0)
996           || ((strcmp(name, ".dtors") == 0
997                || is_prefix_of(".dtors.", name))
998               && strcmp(os->name(), ".fini_array") == 0)))
999     ctors_sections_in_init_array.insert(Section_id(object, shndx));
1000
1001   // FIXME: Handle SHF_LINK_ORDER somewhere.
1002
1003   elfcpp::Elf_Xword orig_flags = os->flags();
1004
1005   *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
1006                                this->script_options_->saw_sections_clause());
1007
1008   // If the flags changed, we may have to change the order.
1009   if ((orig_flags & elfcpp::SHF_ALLOC) != 0)
1010     {
1011       orig_flags &= (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
1012       elfcpp::Elf_Xword new_flags =
1013         os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
1014       if (orig_flags != new_flags)
1015         os->set_order(this->default_section_order(os, false));
1016     }
1017
1018   this->have_added_input_section_ = true;
1019
1020   return os;
1021 }
1022
1023 // Handle a relocation section when doing a relocatable link.
1024
1025 template<int size, bool big_endian>
1026 Output_section*
1027 Layout::layout_reloc(Sized_relobj_file<size, big_endian>* object,
1028                      unsigned int,
1029                      const elfcpp::Shdr<size, big_endian>& shdr,
1030                      Output_section* data_section,
1031                      Relocatable_relocs* rr)
1032 {
1033   gold_assert(parameters->options().relocatable()
1034               || parameters->options().emit_relocs());
1035
1036   int sh_type = shdr.get_sh_type();
1037
1038   std::string name;
1039   if (sh_type == elfcpp::SHT_REL)
1040     name = ".rel";
1041   else if (sh_type == elfcpp::SHT_RELA)
1042     name = ".rela";
1043   else
1044     gold_unreachable();
1045   name += data_section->name();
1046
1047   // In a relocatable link relocs for a grouped section must not be
1048   // combined with other reloc sections.
1049   Output_section* os;
1050   if (!parameters->options().relocatable()
1051       || (data_section->flags() & elfcpp::SHF_GROUP) == 0)
1052     os = this->choose_output_section(object, name.c_str(), sh_type,
1053                                      shdr.get_sh_flags(), false,
1054                                      ORDER_INVALID, false);
1055   else
1056     {
1057       const char* n = this->namepool_.add(name.c_str(), true, NULL);
1058       os = this->make_output_section(n, sh_type, shdr.get_sh_flags(),
1059                                      ORDER_INVALID, false);
1060     }
1061
1062   os->set_should_link_to_symtab();
1063   os->set_info_section(data_section);
1064
1065   Output_section_data* posd;
1066   if (sh_type == elfcpp::SHT_REL)
1067     {
1068       os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
1069       posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
1070                                            size,
1071                                            big_endian>(rr);
1072     }
1073   else if (sh_type == elfcpp::SHT_RELA)
1074     {
1075       os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
1076       posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
1077                                            size,
1078                                            big_endian>(rr);
1079     }
1080   else
1081     gold_unreachable();
1082
1083   os->add_output_section_data(posd);
1084   rr->set_output_data(posd);
1085
1086   return os;
1087 }
1088
1089 // Handle a group section when doing a relocatable link.
1090
1091 template<int size, bool big_endian>
1092 void
1093 Layout::layout_group(Symbol_table* symtab,
1094                      Sized_relobj_file<size, big_endian>* object,
1095                      unsigned int,
1096                      const char* group_section_name,
1097                      const char* signature,
1098                      const elfcpp::Shdr<size, big_endian>& shdr,
1099                      elfcpp::Elf_Word flags,
1100                      std::vector<unsigned int>* shndxes)
1101 {
1102   gold_assert(parameters->options().relocatable());
1103   gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
1104   group_section_name = this->namepool_.add(group_section_name, true, NULL);
1105   Output_section* os = this->make_output_section(group_section_name,
1106                                                  elfcpp::SHT_GROUP,
1107                                                  shdr.get_sh_flags(),
1108                                                  ORDER_INVALID, false);
1109
1110   // We need to find a symbol with the signature in the symbol table.
1111   // If we don't find one now, we need to look again later.
1112   Symbol* sym = symtab->lookup(signature, NULL);
1113   if (sym != NULL)
1114     os->set_info_symndx(sym);
1115   else
1116     {
1117       // Reserve some space to minimize reallocations.
1118       if (this->group_signatures_.empty())
1119         this->group_signatures_.reserve(this->number_of_input_files_ * 16);
1120
1121       // We will wind up using a symbol whose name is the signature.
1122       // So just put the signature in the symbol name pool to save it.
1123       signature = symtab->canonicalize_name(signature);
1124       this->group_signatures_.push_back(Group_signature(os, signature));
1125     }
1126
1127   os->set_should_link_to_symtab();
1128   os->set_entsize(4);
1129
1130   section_size_type entry_count =
1131     convert_to_section_size_type(shdr.get_sh_size() / 4);
1132   Output_section_data* posd =
1133     new Output_data_group<size, big_endian>(object, entry_count, flags,
1134                                             shndxes);
1135   os->add_output_section_data(posd);
1136 }
1137
1138 // Special GNU handling of sections name .eh_frame.  They will
1139 // normally hold exception frame data as defined by the C++ ABI
1140 // (http://codesourcery.com/cxx-abi/).
1141
1142 template<int size, bool big_endian>
1143 Output_section*
1144 Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
1145                         const unsigned char* symbols,
1146                         off_t symbols_size,
1147                         const unsigned char* symbol_names,
1148                         off_t symbol_names_size,
1149                         unsigned int shndx,
1150                         const elfcpp::Shdr<size, big_endian>& shdr,
1151                         unsigned int reloc_shndx, unsigned int reloc_type,
1152                         off_t* off)
1153 {
1154   gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS
1155               || shdr.get_sh_type() == elfcpp::SHT_X86_64_UNWIND);
1156   gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
1157
1158   Output_section* os = this->make_eh_frame_section(object);
1159   if (os == NULL)
1160     return NULL;
1161
1162   gold_assert(this->eh_frame_section_ == os);
1163
1164   elfcpp::Elf_Xword orig_flags = os->flags();
1165
1166   if (!parameters->incremental()
1167       && this->eh_frame_data_->add_ehframe_input_section(object,
1168                                                          symbols,
1169                                                          symbols_size,
1170                                                          symbol_names,
1171                                                          symbol_names_size,
1172                                                          shndx,
1173                                                          reloc_shndx,
1174                                                          reloc_type))
1175     {
1176       os->update_flags_for_input_section(shdr.get_sh_flags());
1177
1178       // A writable .eh_frame section is a RELRO section.
1179       if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1180           != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1181         {
1182           os->set_is_relro();
1183           os->set_order(ORDER_RELRO);
1184         }
1185
1186       // We found a .eh_frame section we are going to optimize, so now
1187       // we can add the set of optimized sections to the output
1188       // section.  We need to postpone adding this until we've found a
1189       // section we can optimize so that the .eh_frame section in
1190       // crtbegin.o winds up at the start of the output section.
1191       if (!this->added_eh_frame_data_)
1192         {
1193           os->add_output_section_data(this->eh_frame_data_);
1194           this->added_eh_frame_data_ = true;
1195         }
1196       *off = -1;
1197     }
1198   else
1199     {
1200       // We couldn't handle this .eh_frame section for some reason.
1201       // Add it as a normal section.
1202       bool saw_sections_clause = this->script_options_->saw_sections_clause();
1203       *off = os->add_input_section(this, object, shndx, ".eh_frame", shdr,
1204                                    reloc_shndx, saw_sections_clause);
1205       this->have_added_input_section_ = true;
1206
1207       if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1208           != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1209         os->set_order(this->default_section_order(os, false));
1210     }
1211
1212   return os;
1213 }
1214
1215 // Create and return the magic .eh_frame section.  Create
1216 // .eh_frame_hdr also if appropriate.  OBJECT is the object with the
1217 // input .eh_frame section; it may be NULL.
1218
1219 Output_section*
1220 Layout::make_eh_frame_section(const Relobj* object)
1221 {
1222   // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than
1223   // SHT_PROGBITS.
1224   Output_section* os = this->choose_output_section(object, ".eh_frame",
1225                                                    elfcpp::SHT_PROGBITS,
1226                                                    elfcpp::SHF_ALLOC, false,
1227                                                    ORDER_EHFRAME, false);
1228   if (os == NULL)
1229     return NULL;
1230
1231   if (this->eh_frame_section_ == NULL)
1232     {
1233       this->eh_frame_section_ = os;
1234       this->eh_frame_data_ = new Eh_frame();
1235
1236       // For incremental linking, we do not optimize .eh_frame sections
1237       // or create a .eh_frame_hdr section.
1238       if (parameters->options().eh_frame_hdr() && !parameters->incremental())
1239         {
1240           Output_section* hdr_os =
1241             this->choose_output_section(NULL, ".eh_frame_hdr",
1242                                         elfcpp::SHT_PROGBITS,
1243                                         elfcpp::SHF_ALLOC, false,
1244                                         ORDER_EHFRAME, false);
1245
1246           if (hdr_os != NULL)
1247             {
1248               Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
1249                                                         this->eh_frame_data_);
1250               hdr_os->add_output_section_data(hdr_posd);
1251
1252               hdr_os->set_after_input_sections();
1253
1254               if (!this->script_options_->saw_phdrs_clause())
1255                 {
1256                   Output_segment* hdr_oseg;
1257                   hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
1258                                                        elfcpp::PF_R);
1259                   hdr_oseg->add_output_section_to_nonload(hdr_os,
1260                                                           elfcpp::PF_R);
1261                 }
1262
1263               this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
1264             }
1265         }
1266     }
1267
1268   return os;
1269 }
1270
1271 // Add an exception frame for a PLT.  This is called from target code.
1272
1273 void
1274 Layout::add_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data,
1275                              size_t cie_length, const unsigned char* fde_data,
1276                              size_t fde_length)
1277 {
1278   if (parameters->incremental())
1279     {
1280       // FIXME: Maybe this could work some day....
1281       return;
1282     }
1283   Output_section* os = this->make_eh_frame_section(NULL);
1284   if (os == NULL)
1285     return;
1286   this->eh_frame_data_->add_ehframe_for_plt(plt, cie_data, cie_length,
1287                                             fde_data, fde_length);
1288   if (!this->added_eh_frame_data_)
1289     {
1290       os->add_output_section_data(this->eh_frame_data_);
1291       this->added_eh_frame_data_ = true;
1292     }
1293 }
1294
1295 // Add POSD to an output section using NAME, TYPE, and FLAGS.  Return
1296 // the output section.
1297
1298 Output_section*
1299 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
1300                                 elfcpp::Elf_Xword flags,
1301                                 Output_section_data* posd,
1302                                 Output_section_order order, bool is_relro)
1303 {
1304   Output_section* os = this->choose_output_section(NULL, name, type, flags,
1305                                                    false, order, is_relro);
1306   if (os != NULL)
1307     os->add_output_section_data(posd);
1308   return os;
1309 }
1310
1311 // Map section flags to segment flags.
1312
1313 elfcpp::Elf_Word
1314 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
1315 {
1316   elfcpp::Elf_Word ret = elfcpp::PF_R;
1317   if ((flags & elfcpp::SHF_WRITE) != 0)
1318     ret |= elfcpp::PF_W;
1319   if ((flags & elfcpp::SHF_EXECINSTR) != 0)
1320     ret |= elfcpp::PF_X;
1321   return ret;
1322 }
1323
1324 // Make a new Output_section, and attach it to segments as
1325 // appropriate.  ORDER is the order in which this section should
1326 // appear in the output segment.  IS_RELRO is true if this is a relro
1327 // (read-only after relocations) section.
1328
1329 Output_section*
1330 Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
1331                             elfcpp::Elf_Xword flags,
1332                             Output_section_order order, bool is_relro)
1333 {
1334   Output_section* os;
1335   if ((flags & elfcpp::SHF_ALLOC) == 0
1336       && strcmp(parameters->options().compress_debug_sections(), "none") != 0
1337       && is_compressible_debug_section(name))
1338     os = new Output_compressed_section(&parameters->options(), name, type,
1339                                        flags);
1340   else if ((flags & elfcpp::SHF_ALLOC) == 0
1341            && parameters->options().strip_debug_non_line()
1342            && strcmp(".debug_abbrev", name) == 0)
1343     {
1344       os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
1345           name, type, flags);
1346       if (this->debug_info_)
1347         this->debug_info_->set_abbreviations(this->debug_abbrev_);
1348     }
1349   else if ((flags & elfcpp::SHF_ALLOC) == 0
1350            && parameters->options().strip_debug_non_line()
1351            && strcmp(".debug_info", name) == 0)
1352     {
1353       os = this->debug_info_ = new Output_reduced_debug_info_section(
1354           name, type, flags);
1355       if (this->debug_abbrev_)
1356         this->debug_info_->set_abbreviations(this->debug_abbrev_);
1357     }
1358   else
1359     {
1360       // Sometimes .init_array*, .preinit_array* and .fini_array* do
1361       // not have correct section types.  Force them here.
1362       if (type == elfcpp::SHT_PROGBITS)
1363         {
1364           if (is_prefix_of(".init_array", name))
1365             type = elfcpp::SHT_INIT_ARRAY;
1366           else if (is_prefix_of(".preinit_array", name))
1367             type = elfcpp::SHT_PREINIT_ARRAY;
1368           else if (is_prefix_of(".fini_array", name))
1369             type = elfcpp::SHT_FINI_ARRAY;
1370         }
1371
1372       // FIXME: const_cast is ugly.
1373       Target* target = const_cast<Target*>(&parameters->target());
1374       os = target->make_output_section(name, type, flags);
1375     }
1376
1377   // With -z relro, we have to recognize the special sections by name.
1378   // There is no other way.
1379   bool is_relro_local = false;
1380   if (!this->script_options_->saw_sections_clause()
1381       && parameters->options().relro()
1382       && type == elfcpp::SHT_PROGBITS
1383       && (flags & elfcpp::SHF_ALLOC) != 0
1384       && (flags & elfcpp::SHF_WRITE) != 0)
1385     {
1386       if (strcmp(name, ".data.rel.ro") == 0)
1387         is_relro = true;
1388       else if (strcmp(name, ".data.rel.ro.local") == 0)
1389         {
1390           is_relro = true;
1391           is_relro_local = true;
1392         }
1393       else if (type == elfcpp::SHT_INIT_ARRAY
1394                || type == elfcpp::SHT_FINI_ARRAY
1395                || type == elfcpp::SHT_PREINIT_ARRAY)
1396         is_relro = true;
1397       else if (strcmp(name, ".ctors") == 0
1398                || strcmp(name, ".dtors") == 0
1399                || strcmp(name, ".jcr") == 0)
1400         is_relro = true;
1401     }
1402
1403   if (is_relro)
1404     os->set_is_relro();
1405
1406   if (order == ORDER_INVALID && (flags & elfcpp::SHF_ALLOC) != 0)
1407     order = this->default_section_order(os, is_relro_local);
1408
1409   os->set_order(order);
1410
1411   parameters->target().new_output_section(os);
1412
1413   this->section_list_.push_back(os);
1414
1415   // The GNU linker by default sorts some sections by priority, so we
1416   // do the same.  We need to know that this might happen before we
1417   // attach any input sections.
1418   if (!this->script_options_->saw_sections_clause()
1419       && !parameters->options().relocatable()
1420       && (strcmp(name, ".init_array") == 0
1421           || strcmp(name, ".fini_array") == 0
1422           || (!parameters->options().ctors_in_init_array()
1423               && (strcmp(name, ".ctors") == 0
1424                   || strcmp(name, ".dtors") == 0))))
1425     os->set_may_sort_attached_input_sections();
1426
1427   // Check for .stab*str sections, as .stab* sections need to link to
1428   // them.
1429   if (type == elfcpp::SHT_STRTAB
1430       && !this->have_stabstr_section_
1431       && strncmp(name, ".stab", 5) == 0
1432       && strcmp(name + strlen(name) - 3, "str") == 0)
1433     this->have_stabstr_section_ = true;
1434
1435   // During a full incremental link, we add patch space to most
1436   // PROGBITS and NOBITS sections.  Flag those that may be
1437   // arbitrarily padded.
1438   if ((type == elfcpp::SHT_PROGBITS || type == elfcpp::SHT_NOBITS)
1439       && order != ORDER_INTERP
1440       && order != ORDER_INIT
1441       && order != ORDER_PLT
1442       && order != ORDER_FINI
1443       && order != ORDER_RELRO_LAST
1444       && order != ORDER_NON_RELRO_FIRST
1445       && strcmp(name, ".ctors") != 0
1446       && strcmp(name, ".dtors") != 0
1447       && strcmp(name, ".jcr") != 0)
1448     {
1449       os->set_is_patch_space_allowed();
1450
1451       // Certain sections require "holes" to be filled with
1452       // specific fill patterns.  These fill patterns may have
1453       // a minimum size, so we must prevent allocations from the
1454       // free list that leave a hole smaller than the minimum.
1455       if (strcmp(name, ".debug_info") == 0)
1456         os->set_free_space_fill(new Output_fill_debug_info(false));
1457       else if (strcmp(name, ".debug_types") == 0)
1458         os->set_free_space_fill(new Output_fill_debug_info(true));
1459       else if (strcmp(name, ".debug_line") == 0)
1460         os->set_free_space_fill(new Output_fill_debug_line());
1461     }
1462
1463   // If we have already attached the sections to segments, then we
1464   // need to attach this one now.  This happens for sections created
1465   // directly by the linker.
1466   if (this->sections_are_attached_)
1467     this->attach_section_to_segment(os);
1468
1469   return os;
1470 }
1471
1472 // Return the default order in which a section should be placed in an
1473 // output segment.  This function captures a lot of the ideas in
1474 // ld/scripttempl/elf.sc in the GNU linker.  Note that the order of a
1475 // linker created section is normally set when the section is created;
1476 // this function is used for input sections.
1477
1478 Output_section_order
1479 Layout::default_section_order(Output_section* os, bool is_relro_local)
1480 {
1481   gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
1482   bool is_write = (os->flags() & elfcpp::SHF_WRITE) != 0;
1483   bool is_execinstr = (os->flags() & elfcpp::SHF_EXECINSTR) != 0;
1484   bool is_bss = false;
1485
1486   switch (os->type())
1487     {
1488     default:
1489     case elfcpp::SHT_PROGBITS:
1490       break;
1491     case elfcpp::SHT_NOBITS:
1492       is_bss = true;
1493       break;
1494     case elfcpp::SHT_RELA:
1495     case elfcpp::SHT_REL:
1496       if (!is_write)
1497         return ORDER_DYNAMIC_RELOCS;
1498       break;
1499     case elfcpp::SHT_HASH:
1500     case elfcpp::SHT_DYNAMIC:
1501     case elfcpp::SHT_SHLIB:
1502     case elfcpp::SHT_DYNSYM:
1503     case elfcpp::SHT_GNU_HASH:
1504     case elfcpp::SHT_GNU_verdef:
1505     case elfcpp::SHT_GNU_verneed:
1506     case elfcpp::SHT_GNU_versym:
1507       if (!is_write)
1508         return ORDER_DYNAMIC_LINKER;
1509       break;
1510     case elfcpp::SHT_NOTE:
1511       return is_write ? ORDER_RW_NOTE : ORDER_RO_NOTE;
1512     }
1513
1514   if ((os->flags() & elfcpp::SHF_TLS) != 0)
1515     return is_bss ? ORDER_TLS_BSS : ORDER_TLS_DATA;
1516
1517   if (!is_bss && !is_write)
1518     {
1519       if (is_execinstr)
1520         {
1521           if (strcmp(os->name(), ".init") == 0)
1522             return ORDER_INIT;
1523           else if (strcmp(os->name(), ".fini") == 0)
1524             return ORDER_FINI;
1525         }
1526       return is_execinstr ? ORDER_TEXT : ORDER_READONLY;
1527     }
1528
1529   if (os->is_relro())
1530     return is_relro_local ? ORDER_RELRO_LOCAL : ORDER_RELRO;
1531
1532   if (os->is_small_section())
1533     return is_bss ? ORDER_SMALL_BSS : ORDER_SMALL_DATA;
1534   if (os->is_large_section())
1535     return is_bss ? ORDER_LARGE_BSS : ORDER_LARGE_DATA;
1536
1537   return is_bss ? ORDER_BSS : ORDER_DATA;
1538 }
1539
1540 // Attach output sections to segments.  This is called after we have
1541 // seen all the input sections.
1542
1543 void
1544 Layout::attach_sections_to_segments()
1545 {
1546   for (Section_list::iterator p = this->section_list_.begin();
1547        p != this->section_list_.end();
1548        ++p)
1549     this->attach_section_to_segment(*p);
1550
1551   this->sections_are_attached_ = true;
1552 }
1553
1554 // Attach an output section to a segment.
1555
1556 void
1557 Layout::attach_section_to_segment(Output_section* os)
1558 {
1559   if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
1560     this->unattached_section_list_.push_back(os);
1561   else
1562     this->attach_allocated_section_to_segment(os);
1563 }
1564
1565 // Attach an allocated output section to a segment.
1566
1567 void
1568 Layout::attach_allocated_section_to_segment(Output_section* os)
1569 {
1570   elfcpp::Elf_Xword flags = os->flags();
1571   gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
1572
1573   if (parameters->options().relocatable())
1574     return;
1575
1576   // If we have a SECTIONS clause, we can't handle the attachment to
1577   // segments until after we've seen all the sections.
1578   if (this->script_options_->saw_sections_clause())
1579     return;
1580
1581   gold_assert(!this->script_options_->saw_phdrs_clause());
1582
1583   // This output section goes into a PT_LOAD segment.
1584
1585   elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
1586
1587   // Check for --section-start.
1588   uint64_t addr;
1589   bool is_address_set = parameters->options().section_start(os->name(), &addr);
1590
1591   // In general the only thing we really care about for PT_LOAD
1592   // segments is whether or not they are writable or executable,
1593   // so that is how we search for them.
1594   // Large data sections also go into their own PT_LOAD segment.
1595   // People who need segments sorted on some other basis will
1596   // have to use a linker script.
1597
1598   Segment_list::const_iterator p;
1599   for (p = this->segment_list_.begin();
1600        p != this->segment_list_.end();
1601        ++p)
1602     {
1603       if ((*p)->type() != elfcpp::PT_LOAD)
1604         continue;
1605       if (!parameters->options().omagic()
1606           && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
1607         continue;
1608       if (parameters->options().rosegment()
1609           && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
1610         continue;
1611       // If -Tbss was specified, we need to separate the data and BSS
1612       // segments.
1613       if (parameters->options().user_set_Tbss())
1614         {
1615           if ((os->type() == elfcpp::SHT_NOBITS)
1616               == (*p)->has_any_data_sections())
1617             continue;
1618         }
1619       if (os->is_large_data_section() && !(*p)->is_large_data_segment())
1620         continue;
1621
1622       if (is_address_set)
1623         {
1624           if ((*p)->are_addresses_set())
1625             continue;
1626
1627           (*p)->add_initial_output_data(os);
1628           (*p)->update_flags_for_output_section(seg_flags);
1629           (*p)->set_addresses(addr, addr);
1630           break;
1631         }
1632
1633       (*p)->add_output_section_to_load(this, os, seg_flags);
1634       break;
1635     }
1636
1637   if (p == this->segment_list_.end())
1638     {
1639       Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
1640                                                        seg_flags);
1641       if (os->is_large_data_section())
1642         oseg->set_is_large_data_segment();
1643       oseg->add_output_section_to_load(this, os, seg_flags);
1644       if (is_address_set)
1645         oseg->set_addresses(addr, addr);
1646     }
1647
1648   // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1649   // segment.
1650   if (os->type() == elfcpp::SHT_NOTE)
1651     {
1652       // See if we already have an equivalent PT_NOTE segment.
1653       for (p = this->segment_list_.begin();
1654            p != segment_list_.end();
1655            ++p)
1656         {
1657           if ((*p)->type() == elfcpp::PT_NOTE
1658               && (((*p)->flags() & elfcpp::PF_W)
1659                   == (seg_flags & elfcpp::PF_W)))
1660             {
1661               (*p)->add_output_section_to_nonload(os, seg_flags);
1662               break;
1663             }
1664         }
1665
1666       if (p == this->segment_list_.end())
1667         {
1668           Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
1669                                                            seg_flags);
1670           oseg->add_output_section_to_nonload(os, seg_flags);
1671         }
1672     }
1673
1674   // If we see a loadable SHF_TLS section, we create a PT_TLS
1675   // segment.  There can only be one such segment.
1676   if ((flags & elfcpp::SHF_TLS) != 0)
1677     {
1678       if (this->tls_segment_ == NULL)
1679         this->make_output_segment(elfcpp::PT_TLS, seg_flags);
1680       this->tls_segment_->add_output_section_to_nonload(os, seg_flags);
1681     }
1682
1683   // If -z relro is in effect, and we see a relro section, we create a
1684   // PT_GNU_RELRO segment.  There can only be one such segment.
1685   if (os->is_relro() && parameters->options().relro())
1686     {
1687       gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
1688       if (this->relro_segment_ == NULL)
1689         this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
1690       this->relro_segment_->add_output_section_to_nonload(os, seg_flags);
1691     }
1692
1693   // If we see a section named .interp, put it into a PT_INTERP
1694   // segment.  This seems broken to me, but this is what GNU ld does,
1695   // and glibc expects it.
1696   if (strcmp(os->name(), ".interp") == 0
1697       && !this->script_options_->saw_phdrs_clause())
1698     {
1699       if (this->interp_segment_ == NULL)
1700         this->make_output_segment(elfcpp::PT_INTERP, seg_flags);
1701       else
1702         gold_warning(_("multiple '.interp' sections in input files "
1703                        "may cause confusing PT_INTERP segment"));
1704       this->interp_segment_->add_output_section_to_nonload(os, seg_flags);
1705     }
1706 }
1707
1708 // Make an output section for a script.
1709
1710 Output_section*
1711 Layout::make_output_section_for_script(
1712     const char* name,
1713     Script_sections::Section_type section_type)
1714 {
1715   name = this->namepool_.add(name, false, NULL);
1716   elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC;
1717   if (section_type == Script_sections::ST_NOLOAD)
1718     sh_flags = 0;
1719   Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
1720                                                  sh_flags, ORDER_INVALID,
1721                                                  false);
1722   os->set_found_in_sections_clause();
1723   if (section_type == Script_sections::ST_NOLOAD)
1724     os->set_is_noload();
1725   return os;
1726 }
1727
1728 // Return the number of segments we expect to see.
1729
1730 size_t
1731 Layout::expected_segment_count() const
1732 {
1733   size_t ret = this->segment_list_.size();
1734
1735   // If we didn't see a SECTIONS clause in a linker script, we should
1736   // already have the complete list of segments.  Otherwise we ask the
1737   // SECTIONS clause how many segments it expects, and add in the ones
1738   // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1739
1740   if (!this->script_options_->saw_sections_clause())
1741     return ret;
1742   else
1743     {
1744       const Script_sections* ss = this->script_options_->script_sections();
1745       return ret + ss->expected_segment_count(this);
1746     }
1747 }
1748
1749 // Handle the .note.GNU-stack section at layout time.  SEEN_GNU_STACK
1750 // is whether we saw a .note.GNU-stack section in the object file.
1751 // GNU_STACK_FLAGS is the section flags.  The flags give the
1752 // protection required for stack memory.  We record this in an
1753 // executable as a PT_GNU_STACK segment.  If an object file does not
1754 // have a .note.GNU-stack segment, we must assume that it is an old
1755 // object.  On some targets that will force an executable stack.
1756
1757 void
1758 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags,
1759                          const Object* obj)
1760 {
1761   if (!seen_gnu_stack)
1762     {
1763       this->input_without_gnu_stack_note_ = true;
1764       if (parameters->options().warn_execstack()
1765           && parameters->target().is_default_stack_executable())
1766         gold_warning(_("%s: missing .note.GNU-stack section"
1767                        " implies executable stack"),
1768                      obj->name().c_str());
1769     }
1770   else
1771     {
1772       this->input_with_gnu_stack_note_ = true;
1773       if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
1774         {
1775           this->input_requires_executable_stack_ = true;
1776           if (parameters->options().warn_execstack()
1777               || parameters->options().is_stack_executable())
1778             gold_warning(_("%s: requires executable stack"),
1779                          obj->name().c_str());
1780         }
1781     }
1782 }
1783
1784 // Create automatic note sections.
1785
1786 void
1787 Layout::create_notes()
1788 {
1789   this->create_gold_note();
1790   this->create_executable_stack_info();
1791   this->create_build_id();
1792 }
1793
1794 // Create the dynamic sections which are needed before we read the
1795 // relocs.
1796
1797 void
1798 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
1799 {
1800   if (parameters->doing_static_link())
1801     return;
1802
1803   this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
1804                                                        elfcpp::SHT_DYNAMIC,
1805                                                        (elfcpp::SHF_ALLOC
1806                                                         | elfcpp::SHF_WRITE),
1807                                                        false, ORDER_RELRO,
1808                                                        true);
1809
1810   // A linker script may discard .dynamic, so check for NULL.
1811   if (this->dynamic_section_ != NULL)
1812     {
1813       this->dynamic_symbol_ =
1814         symtab->define_in_output_data("_DYNAMIC", NULL,
1815                                       Symbol_table::PREDEFINED,
1816                                       this->dynamic_section_, 0, 0,
1817                                       elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
1818                                       elfcpp::STV_HIDDEN, 0, false, false);
1819
1820       this->dynamic_data_ =  new Output_data_dynamic(&this->dynpool_);
1821
1822       this->dynamic_section_->add_output_section_data(this->dynamic_data_);
1823     }
1824 }
1825
1826 // For each output section whose name can be represented as C symbol,
1827 // define __start and __stop symbols for the section.  This is a GNU
1828 // extension.
1829
1830 void
1831 Layout::define_section_symbols(Symbol_table* symtab)
1832 {
1833   for (Section_list::const_iterator p = this->section_list_.begin();
1834        p != this->section_list_.end();
1835        ++p)
1836     {
1837       const char* const name = (*p)->name();
1838       if (is_cident(name))
1839         {
1840           const std::string name_string(name);
1841           const std::string start_name(cident_section_start_prefix
1842                                        + name_string);
1843           const std::string stop_name(cident_section_stop_prefix
1844                                       + name_string);
1845
1846           symtab->define_in_output_data(start_name.c_str(),
1847                                         NULL, // version
1848                                         Symbol_table::PREDEFINED,
1849                                         *p,
1850                                         0, // value
1851                                         0, // symsize
1852                                         elfcpp::STT_NOTYPE,
1853                                         elfcpp::STB_GLOBAL,
1854                                         elfcpp::STV_DEFAULT,
1855                                         0, // nonvis
1856                                         false, // offset_is_from_end
1857                                         true); // only_if_ref
1858
1859           symtab->define_in_output_data(stop_name.c_str(),
1860                                         NULL, // version
1861                                         Symbol_table::PREDEFINED,
1862                                         *p,
1863                                         0, // value
1864                                         0, // symsize
1865                                         elfcpp::STT_NOTYPE,
1866                                         elfcpp::STB_GLOBAL,
1867                                         elfcpp::STV_DEFAULT,
1868                                         0, // nonvis
1869                                         true, // offset_is_from_end
1870                                         true); // only_if_ref
1871         }
1872     }
1873 }
1874
1875 // Define symbols for group signatures.
1876
1877 void
1878 Layout::define_group_signatures(Symbol_table* symtab)
1879 {
1880   for (Group_signatures::iterator p = this->group_signatures_.begin();
1881        p != this->group_signatures_.end();
1882        ++p)
1883     {
1884       Symbol* sym = symtab->lookup(p->signature, NULL);
1885       if (sym != NULL)
1886         p->section->set_info_symndx(sym);
1887       else
1888         {
1889           // Force the name of the group section to the group
1890           // signature, and use the group's section symbol as the
1891           // signature symbol.
1892           if (strcmp(p->section->name(), p->signature) != 0)
1893             {
1894               const char* name = this->namepool_.add(p->signature,
1895                                                      true, NULL);
1896               p->section->set_name(name);
1897             }
1898           p->section->set_needs_symtab_index();
1899           p->section->set_info_section_symndx(p->section);
1900         }
1901     }
1902
1903   this->group_signatures_.clear();
1904 }
1905
1906 // Find the first read-only PT_LOAD segment, creating one if
1907 // necessary.
1908
1909 Output_segment*
1910 Layout::find_first_load_seg()
1911 {
1912   Output_segment* best = NULL;
1913   for (Segment_list::const_iterator p = this->segment_list_.begin();
1914        p != this->segment_list_.end();
1915        ++p)
1916     {
1917       if ((*p)->type() == elfcpp::PT_LOAD
1918           && ((*p)->flags() & elfcpp::PF_R) != 0
1919           && (parameters->options().omagic()
1920               || ((*p)->flags() & elfcpp::PF_W) == 0))
1921         {
1922           if (best == NULL || this->segment_precedes(*p, best))
1923             best = *p;
1924         }
1925     }
1926   if (best != NULL)
1927     return best;
1928
1929   gold_assert(!this->script_options_->saw_phdrs_clause());
1930
1931   Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
1932                                                        elfcpp::PF_R);
1933   return load_seg;
1934 }
1935
1936 // Save states of all current output segments.  Store saved states
1937 // in SEGMENT_STATES.
1938
1939 void
1940 Layout::save_segments(Segment_states* segment_states)
1941 {
1942   for (Segment_list::const_iterator p = this->segment_list_.begin();
1943        p != this->segment_list_.end();
1944        ++p)
1945     {
1946       Output_segment* segment = *p;
1947       // Shallow copy.
1948       Output_segment* copy = new Output_segment(*segment);
1949       (*segment_states)[segment] = copy;
1950     }
1951 }
1952
1953 // Restore states of output segments and delete any segment not found in
1954 // SEGMENT_STATES.
1955
1956 void
1957 Layout::restore_segments(const Segment_states* segment_states)
1958 {
1959   // Go through the segment list and remove any segment added in the
1960   // relaxation loop.
1961   this->tls_segment_ = NULL;
1962   this->relro_segment_ = NULL;
1963   Segment_list::iterator list_iter = this->segment_list_.begin();
1964   while (list_iter != this->segment_list_.end())
1965     {
1966       Output_segment* segment = *list_iter;
1967       Segment_states::const_iterator states_iter =
1968           segment_states->find(segment);
1969       if (states_iter != segment_states->end())
1970         {
1971           const Output_segment* copy = states_iter->second;
1972           // Shallow copy to restore states.
1973           *segment = *copy;
1974
1975           // Also fix up TLS and RELRO segment pointers as appropriate.
1976           if (segment->type() == elfcpp::PT_TLS)
1977             this->tls_segment_ = segment;
1978           else if (segment->type() == elfcpp::PT_GNU_RELRO)
1979             this->relro_segment_ = segment;
1980
1981           ++list_iter;
1982         } 
1983       else
1984         {
1985           list_iter = this->segment_list_.erase(list_iter); 
1986           // This is a segment created during section layout.  It should be
1987           // safe to remove it since we should have removed all pointers to it.
1988           delete segment;
1989         }
1990     }
1991 }
1992
1993 // Clean up after relaxation so that sections can be laid out again.
1994
1995 void
1996 Layout::clean_up_after_relaxation()
1997 {
1998   // Restore the segments to point state just prior to the relaxation loop.
1999   Script_sections* script_section = this->script_options_->script_sections();
2000   script_section->release_segments();
2001   this->restore_segments(this->segment_states_);
2002
2003   // Reset section addresses and file offsets
2004   for (Section_list::iterator p = this->section_list_.begin();
2005        p != this->section_list_.end();
2006        ++p)
2007     {
2008       (*p)->restore_states();
2009
2010       // If an input section changes size because of relaxation,
2011       // we need to adjust the section offsets of all input sections.
2012       // after such a section.
2013       if ((*p)->section_offsets_need_adjustment())
2014         (*p)->adjust_section_offsets();
2015
2016       (*p)->reset_address_and_file_offset();
2017     }
2018   
2019   // Reset special output object address and file offsets.
2020   for (Data_list::iterator p = this->special_output_list_.begin();
2021        p != this->special_output_list_.end();
2022        ++p)
2023     (*p)->reset_address_and_file_offset();
2024
2025   // A linker script may have created some output section data objects.
2026   // They are useless now.
2027   for (Output_section_data_list::const_iterator p =
2028          this->script_output_section_data_list_.begin();
2029        p != this->script_output_section_data_list_.end();
2030        ++p)
2031     delete *p;
2032   this->script_output_section_data_list_.clear(); 
2033 }
2034
2035 // Prepare for relaxation.
2036
2037 void
2038 Layout::prepare_for_relaxation()
2039 {
2040   // Create an relaxation debug check if in debugging mode.
2041   if (is_debugging_enabled(DEBUG_RELAXATION))
2042     this->relaxation_debug_check_ = new Relaxation_debug_check();
2043
2044   // Save segment states.
2045   this->segment_states_ = new Segment_states();
2046   this->save_segments(this->segment_states_);
2047
2048   for(Section_list::const_iterator p = this->section_list_.begin();
2049       p != this->section_list_.end();
2050       ++p)
2051     (*p)->save_states();
2052
2053   if (is_debugging_enabled(DEBUG_RELAXATION))
2054     this->relaxation_debug_check_->check_output_data_for_reset_values(
2055         this->section_list_, this->special_output_list_);
2056
2057   // Also enable recording of output section data from scripts.
2058   this->record_output_section_data_from_script_ = true;
2059 }
2060
2061 // Relaxation loop body:  If target has no relaxation, this runs only once
2062 // Otherwise, the target relaxation hook is called at the end of
2063 // each iteration.  If the hook returns true, it means re-layout of
2064 // section is required.  
2065 //
2066 // The number of segments created by a linking script without a PHDRS
2067 // clause may be affected by section sizes and alignments.  There is
2068 // a remote chance that relaxation causes different number of PT_LOAD
2069 // segments are created and sections are attached to different segments.
2070 // Therefore, we always throw away all segments created during section
2071 // layout.  In order to be able to restart the section layout, we keep
2072 // a copy of the segment list right before the relaxation loop and use
2073 // that to restore the segments.
2074 // 
2075 // PASS is the current relaxation pass number. 
2076 // SYMTAB is a symbol table.
2077 // PLOAD_SEG is the address of a pointer for the load segment.
2078 // PHDR_SEG is a pointer to the PHDR segment.
2079 // SEGMENT_HEADERS points to the output segment header.
2080 // FILE_HEADER points to the output file header.
2081 // PSHNDX is the address to store the output section index.
2082
2083 off_t inline
2084 Layout::relaxation_loop_body(
2085     int pass,
2086     Target* target,
2087     Symbol_table* symtab,
2088     Output_segment** pload_seg,
2089     Output_segment* phdr_seg,
2090     Output_segment_headers* segment_headers,
2091     Output_file_header* file_header,
2092     unsigned int* pshndx)
2093 {
2094   // If this is not the first iteration, we need to clean up after
2095   // relaxation so that we can lay out the sections again.
2096   if (pass != 0)
2097     this->clean_up_after_relaxation();
2098
2099   // If there is a SECTIONS clause, put all the input sections into
2100   // the required order.
2101   Output_segment* load_seg;
2102   if (this->script_options_->saw_sections_clause())
2103     load_seg = this->set_section_addresses_from_script(symtab);
2104   else if (parameters->options().relocatable())
2105     load_seg = NULL;
2106   else
2107     load_seg = this->find_first_load_seg();
2108
2109   if (parameters->options().oformat_enum()
2110       != General_options::OBJECT_FORMAT_ELF)
2111     load_seg = NULL;
2112
2113   // If the user set the address of the text segment, that may not be
2114   // compatible with putting the segment headers and file headers into
2115   // that segment.
2116   if (parameters->options().user_set_Ttext()
2117       && parameters->options().Ttext() % target->common_pagesize() != 0)
2118     {
2119       load_seg = NULL;
2120       phdr_seg = NULL;
2121     }
2122
2123   gold_assert(phdr_seg == NULL
2124               || load_seg != NULL
2125               || this->script_options_->saw_sections_clause());
2126
2127   // If the address of the load segment we found has been set by
2128   // --section-start rather than by a script, then adjust the VMA and
2129   // LMA downward if possible to include the file and section headers.
2130   uint64_t header_gap = 0;
2131   if (load_seg != NULL
2132       && load_seg->are_addresses_set()
2133       && !this->script_options_->saw_sections_clause()
2134       && !parameters->options().relocatable())
2135     {
2136       file_header->finalize_data_size();
2137       segment_headers->finalize_data_size();
2138       size_t sizeof_headers = (file_header->data_size()
2139                                + segment_headers->data_size());
2140       const uint64_t abi_pagesize = target->abi_pagesize();
2141       uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers;
2142       hdr_paddr &= ~(abi_pagesize - 1);
2143       uint64_t subtract = load_seg->paddr() - hdr_paddr;
2144       if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract)
2145         load_seg = NULL;
2146       else
2147         {
2148           load_seg->set_addresses(load_seg->vaddr() - subtract,
2149                                   load_seg->paddr() - subtract);
2150           header_gap = subtract - sizeof_headers;
2151         }
2152     }
2153
2154   // Lay out the segment headers.
2155   if (!parameters->options().relocatable())
2156     {
2157       gold_assert(segment_headers != NULL);
2158       if (header_gap != 0 && load_seg != NULL)
2159         {
2160           Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1);
2161           load_seg->add_initial_output_data(z);
2162         }
2163       if (load_seg != NULL)
2164         load_seg->add_initial_output_data(segment_headers);
2165       if (phdr_seg != NULL)
2166         phdr_seg->add_initial_output_data(segment_headers);
2167     }
2168
2169   // Lay out the file header.
2170   if (load_seg != NULL)
2171     load_seg->add_initial_output_data(file_header);
2172
2173   if (this->script_options_->saw_phdrs_clause()
2174       && !parameters->options().relocatable())
2175     {
2176       // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2177       // clause in a linker script.
2178       Script_sections* ss = this->script_options_->script_sections();
2179       ss->put_headers_in_phdrs(file_header, segment_headers);
2180     }
2181
2182   // We set the output section indexes in set_segment_offsets and
2183   // set_section_indexes.
2184   *pshndx = 1;
2185
2186   // Set the file offsets of all the segments, and all the sections
2187   // they contain.
2188   off_t off;
2189   if (!parameters->options().relocatable())
2190     off = this->set_segment_offsets(target, load_seg, pshndx);
2191   else
2192     off = this->set_relocatable_section_offsets(file_header, pshndx);
2193
2194    // Verify that the dummy relaxation does not change anything.
2195   if (is_debugging_enabled(DEBUG_RELAXATION))
2196     {
2197       if (pass == 0)
2198         this->relaxation_debug_check_->read_sections(this->section_list_);
2199       else
2200         this->relaxation_debug_check_->verify_sections(this->section_list_);
2201     }
2202
2203   *pload_seg = load_seg;
2204   return off;
2205 }
2206
2207 // Search the list of patterns and find the postion of the given section
2208 // name in the output section.  If the section name matches a glob
2209 // pattern and a non-glob name, then the non-glob position takes
2210 // precedence.  Return 0 if no match is found.
2211
2212 unsigned int
2213 Layout::find_section_order_index(const std::string& section_name)
2214 {
2215   Unordered_map<std::string, unsigned int>::iterator map_it;
2216   map_it = this->input_section_position_.find(section_name);
2217   if (map_it != this->input_section_position_.end())
2218     return map_it->second;
2219
2220   // Absolute match failed.  Linear search the glob patterns.
2221   std::vector<std::string>::iterator it;
2222   for (it = this->input_section_glob_.begin();
2223        it != this->input_section_glob_.end();
2224        ++it)
2225     {
2226        if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0)
2227          {
2228            map_it = this->input_section_position_.find(*it);
2229            gold_assert(map_it != this->input_section_position_.end());
2230            return map_it->second;
2231          }
2232     }
2233   return 0;
2234 }
2235
2236 // Read the sequence of input sections from the file specified with
2237 // option --section-ordering-file.
2238
2239 void
2240 Layout::read_layout_from_file()
2241 {
2242   const char* filename = parameters->options().section_ordering_file();
2243   std::ifstream in;
2244   std::string line;
2245
2246   in.open(filename);
2247   if (!in)
2248     gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2249                filename, strerror(errno));
2250
2251   std::getline(in, line);   // this chops off the trailing \n, if any
2252   unsigned int position = 1;
2253   this->set_section_ordering_specified();
2254
2255   while (in)
2256     {
2257       if (!line.empty() && line[line.length() - 1] == '\r')   // Windows
2258         line.resize(line.length() - 1);
2259       // Ignore comments, beginning with '#'
2260       if (line[0] == '#')
2261         {
2262           std::getline(in, line);
2263           continue;
2264         }
2265       this->input_section_position_[line] = position;
2266       // Store all glob patterns in a vector.
2267       if (is_wildcard_string(line.c_str()))
2268         this->input_section_glob_.push_back(line);
2269       position++;
2270       std::getline(in, line);
2271     }
2272 }
2273
2274 // Finalize the layout.  When this is called, we have created all the
2275 // output sections and all the output segments which are based on
2276 // input sections.  We have several things to do, and we have to do
2277 // them in the right order, so that we get the right results correctly
2278 // and efficiently.
2279
2280 // 1) Finalize the list of output segments and create the segment
2281 // table header.
2282
2283 // 2) Finalize the dynamic symbol table and associated sections.
2284
2285 // 3) Determine the final file offset of all the output segments.
2286
2287 // 4) Determine the final file offset of all the SHF_ALLOC output
2288 // sections.
2289
2290 // 5) Create the symbol table sections and the section name table
2291 // section.
2292
2293 // 6) Finalize the symbol table: set symbol values to their final
2294 // value and make a final determination of which symbols are going
2295 // into the output symbol table.
2296
2297 // 7) Create the section table header.
2298
2299 // 8) Determine the final file offset of all the output sections which
2300 // are not SHF_ALLOC, including the section table header.
2301
2302 // 9) Finalize the ELF file header.
2303
2304 // This function returns the size of the output file.
2305
2306 off_t
2307 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
2308                  Target* target, const Task* task)
2309 {
2310   target->finalize_sections(this, input_objects, symtab);
2311
2312   this->count_local_symbols(task, input_objects);
2313
2314   this->link_stabs_sections();
2315
2316   Output_segment* phdr_seg = NULL;
2317   if (!parameters->options().relocatable() && !parameters->doing_static_link())
2318     {
2319       // There was a dynamic object in the link.  We need to create
2320       // some information for the dynamic linker.
2321
2322       // Create the PT_PHDR segment which will hold the program
2323       // headers.
2324       if (!this->script_options_->saw_phdrs_clause())
2325         phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
2326
2327       // Create the dynamic symbol table, including the hash table.
2328       Output_section* dynstr;
2329       std::vector<Symbol*> dynamic_symbols;
2330       unsigned int local_dynamic_count;
2331       Versions versions(*this->script_options()->version_script_info(),
2332                         &this->dynpool_);
2333       this->create_dynamic_symtab(input_objects, symtab, &dynstr,
2334                                   &local_dynamic_count, &dynamic_symbols,
2335                                   &versions);
2336
2337       // Create the .interp section to hold the name of the
2338       // interpreter, and put it in a PT_INTERP segment.  Don't do it
2339       // if we saw a .interp section in an input file.
2340       if ((!parameters->options().shared()
2341            || parameters->options().dynamic_linker() != NULL)
2342           && this->interp_segment_ == NULL)
2343         this->create_interp(target);
2344
2345       // Finish the .dynamic section to hold the dynamic data, and put
2346       // it in a PT_DYNAMIC segment.
2347       this->finish_dynamic_section(input_objects, symtab);
2348
2349       // We should have added everything we need to the dynamic string
2350       // table.
2351       this->dynpool_.set_string_offsets();
2352
2353       // Create the version sections.  We can't do this until the
2354       // dynamic string table is complete.
2355       this->create_version_sections(&versions, symtab, local_dynamic_count,
2356                                     dynamic_symbols, dynstr);
2357
2358       // Set the size of the _DYNAMIC symbol.  We can't do this until
2359       // after we call create_version_sections.
2360       this->set_dynamic_symbol_size(symtab);
2361     }
2362   
2363   // Create segment headers.
2364   Output_segment_headers* segment_headers =
2365     (parameters->options().relocatable()
2366      ? NULL
2367      : new Output_segment_headers(this->segment_list_));
2368
2369   // Lay out the file header.
2370   Output_file_header* file_header = new Output_file_header(target, symtab,
2371                                                            segment_headers);
2372
2373   this->special_output_list_.push_back(file_header);
2374   if (segment_headers != NULL)
2375     this->special_output_list_.push_back(segment_headers);
2376
2377   // Find approriate places for orphan output sections if we are using
2378   // a linker script.
2379   if (this->script_options_->saw_sections_clause())
2380     this->place_orphan_sections_in_script();
2381   
2382   Output_segment* load_seg;
2383   off_t off;
2384   unsigned int shndx;
2385   int pass = 0;
2386
2387   // Take a snapshot of the section layout as needed.
2388   if (target->may_relax())
2389     this->prepare_for_relaxation();
2390   
2391   // Run the relaxation loop to lay out sections.
2392   do
2393     {
2394       off = this->relaxation_loop_body(pass, target, symtab, &load_seg,
2395                                        phdr_seg, segment_headers, file_header,
2396                                        &shndx);
2397       pass++;
2398     }
2399   while (target->may_relax()
2400          && target->relax(pass, input_objects, symtab, this, task));
2401
2402   // Set the file offsets of all the non-data sections we've seen so
2403   // far which don't have to wait for the input sections.  We need
2404   // this in order to finalize local symbols in non-allocated
2405   // sections.
2406   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2407
2408   // Set the section indexes of all unallocated sections seen so far,
2409   // in case any of them are somehow referenced by a symbol.
2410   shndx = this->set_section_indexes(shndx);
2411
2412   // Create the symbol table sections.
2413   this->create_symtab_sections(input_objects, symtab, shndx, &off);
2414   if (!parameters->doing_static_link())
2415     this->assign_local_dynsym_offsets(input_objects);
2416
2417   // Process any symbol assignments from a linker script.  This must
2418   // be called after the symbol table has been finalized.
2419   this->script_options_->finalize_symbols(symtab, this);
2420
2421   // Create the incremental inputs sections.
2422   if (this->incremental_inputs_)
2423     {
2424       this->incremental_inputs_->finalize();
2425       this->create_incremental_info_sections(symtab);
2426     }
2427
2428   // Create the .shstrtab section.
2429   Output_section* shstrtab_section = this->create_shstrtab();
2430
2431   // Set the file offsets of the rest of the non-data sections which
2432   // don't have to wait for the input sections.
2433   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2434
2435   // Now that all sections have been created, set the section indexes
2436   // for any sections which haven't been done yet.
2437   shndx = this->set_section_indexes(shndx);
2438
2439   // Create the section table header.
2440   this->create_shdrs(shstrtab_section, &off);
2441
2442   // If there are no sections which require postprocessing, we can
2443   // handle the section names now, and avoid a resize later.
2444   if (!this->any_postprocessing_sections_)
2445     {
2446       off = this->set_section_offsets(off,
2447                                       POSTPROCESSING_SECTIONS_PASS);
2448       off =
2449           this->set_section_offsets(off,
2450                                     STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
2451     }
2452
2453   file_header->set_section_info(this->section_headers_, shstrtab_section);
2454
2455   // Now we know exactly where everything goes in the output file
2456   // (except for non-allocated sections which require postprocessing).
2457   Output_data::layout_complete();
2458
2459   this->output_file_size_ = off;
2460
2461   return off;
2462 }
2463
2464 // Create a note header following the format defined in the ELF ABI.
2465 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2466 // of the section to create, DESCSZ is the size of the descriptor.
2467 // ALLOCATE is true if the section should be allocated in memory.
2468 // This returns the new note section.  It sets *TRAILING_PADDING to
2469 // the number of trailing zero bytes required.
2470
2471 Output_section*
2472 Layout::create_note(const char* name, int note_type,
2473                     const char* section_name, size_t descsz,
2474                     bool allocate, size_t* trailing_padding)
2475 {
2476   // Authorities all agree that the values in a .note field should
2477   // be aligned on 4-byte boundaries for 32-bit binaries.  However,
2478   // they differ on what the alignment is for 64-bit binaries.
2479   // The GABI says unambiguously they take 8-byte alignment:
2480   //    http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2481   // Other documentation says alignment should always be 4 bytes:
2482   //    http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2483   // GNU ld and GNU readelf both support the latter (at least as of
2484   // version 2.16.91), and glibc always generates the latter for
2485   // .note.ABI-tag (as of version 1.6), so that's the one we go with
2486   // here.
2487 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION   // This is not defined by default.
2488   const int size = parameters->target().get_size();
2489 #else
2490   const int size = 32;
2491 #endif
2492
2493   // The contents of the .note section.
2494   size_t namesz = strlen(name) + 1;
2495   size_t aligned_namesz = align_address(namesz, size / 8);
2496   size_t aligned_descsz = align_address(descsz, size / 8);
2497
2498   size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
2499
2500   unsigned char* buffer = new unsigned char[notehdrsz];
2501   memset(buffer, 0, notehdrsz);
2502
2503   bool is_big_endian = parameters->target().is_big_endian();
2504
2505   if (size == 32)
2506     {
2507       if (!is_big_endian)
2508         {
2509           elfcpp::Swap<32, false>::writeval(buffer, namesz);
2510           elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
2511           elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
2512         }
2513       else
2514         {
2515           elfcpp::Swap<32, true>::writeval(buffer, namesz);
2516           elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
2517           elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
2518         }
2519     }
2520   else if (size == 64)
2521     {
2522       if (!is_big_endian)
2523         {
2524           elfcpp::Swap<64, false>::writeval(buffer, namesz);
2525           elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
2526           elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
2527         }
2528       else
2529         {
2530           elfcpp::Swap<64, true>::writeval(buffer, namesz);
2531           elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
2532           elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
2533         }
2534     }
2535   else
2536     gold_unreachable();
2537
2538   memcpy(buffer + 3 * (size / 8), name, namesz);
2539
2540   elfcpp::Elf_Xword flags = 0;
2541   Output_section_order order = ORDER_INVALID;
2542   if (allocate)
2543     {
2544       flags = elfcpp::SHF_ALLOC;
2545       order = ORDER_RO_NOTE;
2546     }
2547   Output_section* os = this->choose_output_section(NULL, section_name,
2548                                                    elfcpp::SHT_NOTE,
2549                                                    flags, false, order, false);
2550   if (os == NULL)
2551     return NULL;
2552
2553   Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
2554                                                            size / 8,
2555                                                            "** note header");
2556   os->add_output_section_data(posd);
2557
2558   *trailing_padding = aligned_descsz - descsz;
2559
2560   return os;
2561 }
2562
2563 // For an executable or shared library, create a note to record the
2564 // version of gold used to create the binary.
2565
2566 void
2567 Layout::create_gold_note()
2568 {
2569   if (parameters->options().relocatable()
2570       || parameters->incremental_update())
2571     return;
2572
2573   std::string desc = std::string("gold ") + gold::get_version_string();
2574
2575   size_t trailing_padding;
2576   Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
2577                                          ".note.gnu.gold-version", desc.size(),
2578                                          false, &trailing_padding);
2579   if (os == NULL)
2580     return;
2581
2582   Output_section_data* posd = new Output_data_const(desc, 4);
2583   os->add_output_section_data(posd);
2584
2585   if (trailing_padding > 0)
2586     {
2587       posd = new Output_data_zero_fill(trailing_padding, 0);
2588       os->add_output_section_data(posd);
2589     }
2590 }
2591
2592 // Record whether the stack should be executable.  This can be set
2593 // from the command line using the -z execstack or -z noexecstack
2594 // options.  Otherwise, if any input file has a .note.GNU-stack
2595 // section with the SHF_EXECINSTR flag set, the stack should be
2596 // executable.  Otherwise, if at least one input file a
2597 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2598 // section, we use the target default for whether the stack should be
2599 // executable.  Otherwise, we don't generate a stack note.  When
2600 // generating a object file, we create a .note.GNU-stack section with
2601 // the appropriate marking.  When generating an executable or shared
2602 // library, we create a PT_GNU_STACK segment.
2603
2604 void
2605 Layout::create_executable_stack_info()
2606 {
2607   bool is_stack_executable;
2608   if (parameters->options().is_execstack_set())
2609     is_stack_executable = parameters->options().is_stack_executable();
2610   else if (!this->input_with_gnu_stack_note_)
2611     return;
2612   else
2613     {
2614       if (this->input_requires_executable_stack_)
2615         is_stack_executable = true;
2616       else if (this->input_without_gnu_stack_note_)
2617         is_stack_executable =
2618           parameters->target().is_default_stack_executable();
2619       else
2620         is_stack_executable = false;
2621     }
2622
2623   if (parameters->options().relocatable())
2624     {
2625       const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
2626       elfcpp::Elf_Xword flags = 0;
2627       if (is_stack_executable)
2628         flags |= elfcpp::SHF_EXECINSTR;
2629       this->make_output_section(name, elfcpp::SHT_PROGBITS, flags,
2630                                 ORDER_INVALID, false);
2631     }
2632   else
2633     {
2634       if (this->script_options_->saw_phdrs_clause())
2635         return;
2636       int flags = elfcpp::PF_R | elfcpp::PF_W;
2637       if (is_stack_executable)
2638         flags |= elfcpp::PF_X;
2639       this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
2640     }
2641 }
2642
2643 // If --build-id was used, set up the build ID note.
2644
2645 void
2646 Layout::create_build_id()
2647 {
2648   if (!parameters->options().user_set_build_id())
2649     return;
2650
2651   const char* style = parameters->options().build_id();
2652   if (strcmp(style, "none") == 0)
2653     return;
2654
2655   // Set DESCSZ to the size of the note descriptor.  When possible,
2656   // set DESC to the note descriptor contents.
2657   size_t descsz;
2658   std::string desc;
2659   if (strcmp(style, "md5") == 0)
2660     descsz = 128 / 8;
2661   else if (strcmp(style, "sha1") == 0)
2662     descsz = 160 / 8;
2663   else if (strcmp(style, "uuid") == 0)
2664     {
2665       const size_t uuidsz = 128 / 8;
2666
2667       char buffer[uuidsz];
2668       memset(buffer, 0, uuidsz);
2669
2670       int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
2671       if (descriptor < 0)
2672         gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2673                    strerror(errno));
2674       else
2675         {
2676           ssize_t got = ::read(descriptor, buffer, uuidsz);
2677           release_descriptor(descriptor, true);
2678           if (got < 0)
2679             gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
2680           else if (static_cast<size_t>(got) != uuidsz)
2681             gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
2682                        uuidsz, got);
2683         }
2684
2685       desc.assign(buffer, uuidsz);
2686       descsz = uuidsz;
2687     }
2688   else if (strncmp(style, "0x", 2) == 0)
2689     {
2690       hex_init();
2691       const char* p = style + 2;
2692       while (*p != '\0')
2693         {
2694           if (hex_p(p[0]) && hex_p(p[1]))
2695             {
2696               char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
2697               desc += c;
2698               p += 2;
2699             }
2700           else if (*p == '-' || *p == ':')
2701             ++p;
2702           else
2703             gold_fatal(_("--build-id argument '%s' not a valid hex number"),
2704                        style);
2705         }
2706       descsz = desc.size();
2707     }
2708   else
2709     gold_fatal(_("unrecognized --build-id argument '%s'"), style);
2710
2711   // Create the note.
2712   size_t trailing_padding;
2713   Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
2714                                          ".note.gnu.build-id", descsz, true,
2715                                          &trailing_padding);
2716   if (os == NULL)
2717     return;
2718
2719   if (!desc.empty())
2720     {
2721       // We know the value already, so we fill it in now.
2722       gold_assert(desc.size() == descsz);
2723
2724       Output_section_data* posd = new Output_data_const(desc, 4);
2725       os->add_output_section_data(posd);
2726
2727       if (trailing_padding != 0)
2728         {
2729           posd = new Output_data_zero_fill(trailing_padding, 0);
2730           os->add_output_section_data(posd);
2731         }
2732     }
2733   else
2734     {
2735       // We need to compute a checksum after we have completed the
2736       // link.
2737       gold_assert(trailing_padding == 0);
2738       this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
2739       os->add_output_section_data(this->build_id_note_);
2740     }
2741 }
2742
2743 // If we have both .stabXX and .stabXXstr sections, then the sh_link
2744 // field of the former should point to the latter.  I'm not sure who
2745 // started this, but the GNU linker does it, and some tools depend
2746 // upon it.
2747
2748 void
2749 Layout::link_stabs_sections()
2750 {
2751   if (!this->have_stabstr_section_)
2752     return;
2753
2754   for (Section_list::iterator p = this->section_list_.begin();
2755        p != this->section_list_.end();
2756        ++p)
2757     {
2758       if ((*p)->type() != elfcpp::SHT_STRTAB)
2759         continue;
2760
2761       const char* name = (*p)->name();
2762       if (strncmp(name, ".stab", 5) != 0)
2763         continue;
2764
2765       size_t len = strlen(name);
2766       if (strcmp(name + len - 3, "str") != 0)
2767         continue;
2768
2769       std::string stab_name(name, len - 3);
2770       Output_section* stab_sec;
2771       stab_sec = this->find_output_section(stab_name.c_str());
2772       if (stab_sec != NULL)
2773         stab_sec->set_link_section(*p);
2774     }
2775 }
2776
2777 // Create .gnu_incremental_inputs and related sections needed
2778 // for the next run of incremental linking to check what has changed.
2779
2780 void
2781 Layout::create_incremental_info_sections(Symbol_table* symtab)
2782 {
2783   Incremental_inputs* incr = this->incremental_inputs_;
2784
2785   gold_assert(incr != NULL);
2786
2787   // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
2788   incr->create_data_sections(symtab);
2789
2790   // Add the .gnu_incremental_inputs section.
2791   const char* incremental_inputs_name =
2792     this->namepool_.add(".gnu_incremental_inputs", false, NULL);
2793   Output_section* incremental_inputs_os =
2794     this->make_output_section(incremental_inputs_name,
2795                               elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0,
2796                               ORDER_INVALID, false);
2797   incremental_inputs_os->add_output_section_data(incr->inputs_section());
2798
2799   // Add the .gnu_incremental_symtab section.
2800   const char* incremental_symtab_name =
2801     this->namepool_.add(".gnu_incremental_symtab", false, NULL);
2802   Output_section* incremental_symtab_os =
2803     this->make_output_section(incremental_symtab_name,
2804                               elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0,
2805                               ORDER_INVALID, false);
2806   incremental_symtab_os->add_output_section_data(incr->symtab_section());
2807   incremental_symtab_os->set_entsize(4);
2808
2809   // Add the .gnu_incremental_relocs section.
2810   const char* incremental_relocs_name =
2811     this->namepool_.add(".gnu_incremental_relocs", false, NULL);
2812   Output_section* incremental_relocs_os =
2813     this->make_output_section(incremental_relocs_name,
2814                               elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0,
2815                               ORDER_INVALID, false);
2816   incremental_relocs_os->add_output_section_data(incr->relocs_section());
2817   incremental_relocs_os->set_entsize(incr->relocs_entsize());
2818
2819   // Add the .gnu_incremental_got_plt section.
2820   const char* incremental_got_plt_name =
2821     this->namepool_.add(".gnu_incremental_got_plt", false, NULL);
2822   Output_section* incremental_got_plt_os =
2823     this->make_output_section(incremental_got_plt_name,
2824                               elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0,
2825                               ORDER_INVALID, false);
2826   incremental_got_plt_os->add_output_section_data(incr->got_plt_section());
2827
2828   // Add the .gnu_incremental_strtab section.
2829   const char* incremental_strtab_name =
2830     this->namepool_.add(".gnu_incremental_strtab", false, NULL);
2831   Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name,
2832                                                         elfcpp::SHT_STRTAB, 0,
2833                                                         ORDER_INVALID, false);
2834   Output_data_strtab* strtab_data =
2835       new Output_data_strtab(incr->get_stringpool());
2836   incremental_strtab_os->add_output_section_data(strtab_data);
2837
2838   incremental_inputs_os->set_after_input_sections();
2839   incremental_symtab_os->set_after_input_sections();
2840   incremental_relocs_os->set_after_input_sections();
2841   incremental_got_plt_os->set_after_input_sections();
2842
2843   incremental_inputs_os->set_link_section(incremental_strtab_os);
2844   incremental_symtab_os->set_link_section(incremental_inputs_os);
2845   incremental_relocs_os->set_link_section(incremental_inputs_os);
2846   incremental_got_plt_os->set_link_section(incremental_inputs_os);
2847 }
2848
2849 // Return whether SEG1 should be before SEG2 in the output file.  This
2850 // is based entirely on the segment type and flags.  When this is
2851 // called the segment addresses have normally not yet been set.
2852
2853 bool
2854 Layout::segment_precedes(const Output_segment* seg1,
2855                          const Output_segment* seg2)
2856 {
2857   elfcpp::Elf_Word type1 = seg1->type();
2858   elfcpp::Elf_Word type2 = seg2->type();
2859
2860   // The single PT_PHDR segment is required to precede any loadable
2861   // segment.  We simply make it always first.
2862   if (type1 == elfcpp::PT_PHDR)
2863     {
2864       gold_assert(type2 != elfcpp::PT_PHDR);
2865       return true;
2866     }
2867   if (type2 == elfcpp::PT_PHDR)
2868     return false;
2869
2870   // The single PT_INTERP segment is required to precede any loadable
2871   // segment.  We simply make it always second.
2872   if (type1 == elfcpp::PT_INTERP)
2873     {
2874       gold_assert(type2 != elfcpp::PT_INTERP);
2875       return true;
2876     }
2877   if (type2 == elfcpp::PT_INTERP)
2878     return false;
2879
2880   // We then put PT_LOAD segments before any other segments.
2881   if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
2882     return true;
2883   if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
2884     return false;
2885
2886   // We put the PT_TLS segment last except for the PT_GNU_RELRO
2887   // segment, because that is where the dynamic linker expects to find
2888   // it (this is just for efficiency; other positions would also work
2889   // correctly).
2890   if (type1 == elfcpp::PT_TLS
2891       && type2 != elfcpp::PT_TLS
2892       && type2 != elfcpp::PT_GNU_RELRO)
2893     return false;
2894   if (type2 == elfcpp::PT_TLS
2895       && type1 != elfcpp::PT_TLS
2896       && type1 != elfcpp::PT_GNU_RELRO)
2897     return true;
2898
2899   // We put the PT_GNU_RELRO segment last, because that is where the
2900   // dynamic linker expects to find it (as with PT_TLS, this is just
2901   // for efficiency).
2902   if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
2903     return false;
2904   if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
2905     return true;
2906
2907   const elfcpp::Elf_Word flags1 = seg1->flags();
2908   const elfcpp::Elf_Word flags2 = seg2->flags();
2909
2910   // The order of non-PT_LOAD segments is unimportant.  We simply sort
2911   // by the numeric segment type and flags values.  There should not
2912   // be more than one segment with the same type and flags.
2913   if (type1 != elfcpp::PT_LOAD)
2914     {
2915       if (type1 != type2)
2916         return type1 < type2;
2917       gold_assert(flags1 != flags2);
2918       return flags1 < flags2;
2919     }
2920
2921   // If the addresses are set already, sort by load address.
2922   if (seg1->are_addresses_set())
2923     {
2924       if (!seg2->are_addresses_set())
2925         return true;
2926
2927       unsigned int section_count1 = seg1->output_section_count();
2928       unsigned int section_count2 = seg2->output_section_count();
2929       if (section_count1 == 0 && section_count2 > 0)
2930         return true;
2931       if (section_count1 > 0 && section_count2 == 0)
2932         return false;
2933
2934       uint64_t paddr1 = (seg1->are_addresses_set()
2935                          ? seg1->paddr()
2936                          : seg1->first_section_load_address());
2937       uint64_t paddr2 = (seg2->are_addresses_set()
2938                          ? seg2->paddr()
2939                          : seg2->first_section_load_address());
2940
2941       if (paddr1 != paddr2)
2942         return paddr1 < paddr2;
2943     }
2944   else if (seg2->are_addresses_set())
2945     return false;
2946
2947   // A segment which holds large data comes after a segment which does
2948   // not hold large data.
2949   if (seg1->is_large_data_segment())
2950     {
2951       if (!seg2->is_large_data_segment())
2952         return false;
2953     }
2954   else if (seg2->is_large_data_segment())
2955     return true;
2956
2957   // Otherwise, we sort PT_LOAD segments based on the flags.  Readonly
2958   // segments come before writable segments.  Then writable segments
2959   // with data come before writable segments without data.  Then
2960   // executable segments come before non-executable segments.  Then
2961   // the unlikely case of a non-readable segment comes before the
2962   // normal case of a readable segment.  If there are multiple
2963   // segments with the same type and flags, we require that the
2964   // address be set, and we sort by virtual address and then physical
2965   // address.
2966   if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
2967     return (flags1 & elfcpp::PF_W) == 0;
2968   if ((flags1 & elfcpp::PF_W) != 0
2969       && seg1->has_any_data_sections() != seg2->has_any_data_sections())
2970     return seg1->has_any_data_sections();
2971   if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
2972     return (flags1 & elfcpp::PF_X) != 0;
2973   if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
2974     return (flags1 & elfcpp::PF_R) == 0;
2975
2976   // We shouldn't get here--we shouldn't create segments which we
2977   // can't distinguish.  Unless of course we are using a weird linker
2978   // script.
2979   gold_assert(this->script_options_->saw_phdrs_clause());
2980   return false;
2981 }
2982
2983 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
2984
2985 static off_t
2986 align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
2987 {
2988   uint64_t unsigned_off = off;
2989   uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
2990                           | (addr & (abi_pagesize - 1)));
2991   if (aligned_off < unsigned_off)
2992     aligned_off += abi_pagesize;
2993   return aligned_off;
2994 }
2995
2996 // Set the file offsets of all the segments, and all the sections they
2997 // contain.  They have all been created.  LOAD_SEG must be be laid out
2998 // first.  Return the offset of the data to follow.
2999
3000 off_t
3001 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
3002                             unsigned int* pshndx)
3003 {
3004   // Sort them into the final order.  We use a stable sort so that we
3005   // don't randomize the order of indistinguishable segments created
3006   // by linker scripts.
3007   std::stable_sort(this->segment_list_.begin(), this->segment_list_.end(),
3008                    Layout::Compare_segments(this));
3009
3010   // Find the PT_LOAD segments, and set their addresses and offsets
3011   // and their section's addresses and offsets.
3012   uint64_t addr;
3013   if (parameters->options().user_set_Ttext())
3014     addr = parameters->options().Ttext();
3015   else if (parameters->options().output_is_position_independent())
3016     addr = 0;
3017   else
3018     addr = target->default_text_segment_address();
3019   off_t off = 0;
3020
3021   // If LOAD_SEG is NULL, then the file header and segment headers
3022   // will not be loadable.  But they still need to be at offset 0 in
3023   // the file.  Set their offsets now.
3024   if (load_seg == NULL)
3025     {
3026       for (Data_list::iterator p = this->special_output_list_.begin();
3027            p != this->special_output_list_.end();
3028            ++p)
3029         {
3030           off = align_address(off, (*p)->addralign());
3031           (*p)->set_address_and_file_offset(0, off);
3032           off += (*p)->data_size();
3033         }
3034     }
3035
3036   unsigned int increase_relro = this->increase_relro_;
3037   if (this->script_options_->saw_sections_clause())
3038     increase_relro = 0;
3039
3040   const bool check_sections = parameters->options().check_sections();
3041   Output_segment* last_load_segment = NULL;
3042
3043   for (Segment_list::iterator p = this->segment_list_.begin();
3044        p != this->segment_list_.end();
3045        ++p)
3046     {
3047       if ((*p)->type() == elfcpp::PT_LOAD)
3048         {
3049           if (load_seg != NULL && load_seg != *p)
3050             gold_unreachable();
3051           load_seg = NULL;
3052
3053           bool are_addresses_set = (*p)->are_addresses_set();
3054           if (are_addresses_set)
3055             {
3056               // When it comes to setting file offsets, we care about
3057               // the physical address.
3058               addr = (*p)->paddr();
3059             }
3060           else if (parameters->options().user_set_Ttext()
3061                    && ((*p)->flags() & elfcpp::PF_W) == 0)
3062             {
3063               are_addresses_set = true;
3064             }
3065           else if (parameters->options().user_set_Tdata()
3066                    && ((*p)->flags() & elfcpp::PF_W) != 0
3067                    && (!parameters->options().user_set_Tbss()
3068                        || (*p)->has_any_data_sections()))
3069             {
3070               addr = parameters->options().Tdata();
3071               are_addresses_set = true;
3072             }
3073           else if (parameters->options().user_set_Tbss()
3074                    && ((*p)->flags() & elfcpp::PF_W) != 0
3075                    && !(*p)->has_any_data_sections())
3076             {
3077               addr = parameters->options().Tbss();
3078               are_addresses_set = true;
3079             }
3080
3081           uint64_t orig_addr = addr;
3082           uint64_t orig_off = off;
3083
3084           uint64_t aligned_addr = 0;
3085           uint64_t abi_pagesize = target->abi_pagesize();
3086           uint64_t common_pagesize = target->common_pagesize();
3087
3088           if (!parameters->options().nmagic()
3089               && !parameters->options().omagic())
3090             (*p)->set_minimum_p_align(common_pagesize);
3091
3092           if (!are_addresses_set)
3093             {
3094               // Skip the address forward one page, maintaining the same
3095               // position within the page.  This lets us store both segments
3096               // overlapping on a single page in the file, but the loader will
3097               // put them on different pages in memory. We will revisit this
3098               // decision once we know the size of the segment.
3099
3100               addr = align_address(addr, (*p)->maximum_alignment());
3101               aligned_addr = addr;
3102
3103               if ((addr & (abi_pagesize - 1)) != 0)
3104                 addr = addr + abi_pagesize;
3105
3106               off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3107             }
3108
3109           if (!parameters->options().nmagic()
3110               && !parameters->options().omagic())
3111             off = align_file_offset(off, addr, abi_pagesize);
3112           else if (load_seg == NULL)
3113             {
3114               // This is -N or -n with a section script which prevents
3115               // us from using a load segment.  We need to ensure that
3116               // the file offset is aligned to the alignment of the
3117               // segment.  This is because the linker script
3118               // implicitly assumed a zero offset.  If we don't align
3119               // here, then the alignment of the sections in the
3120               // linker script may not match the alignment of the
3121               // sections in the set_section_addresses call below,
3122               // causing an error about dot moving backward.
3123               off = align_address(off, (*p)->maximum_alignment());
3124             }
3125
3126           unsigned int shndx_hold = *pshndx;
3127           bool has_relro = false;
3128           uint64_t new_addr = (*p)->set_section_addresses(this, false, addr,
3129                                                           &increase_relro,
3130                                                           &has_relro,
3131                                                           &off, pshndx);
3132
3133           // Now that we know the size of this segment, we may be able
3134           // to save a page in memory, at the cost of wasting some
3135           // file space, by instead aligning to the start of a new
3136           // page.  Here we use the real machine page size rather than
3137           // the ABI mandated page size.  If the segment has been
3138           // aligned so that the relro data ends at a page boundary,
3139           // we do not try to realign it.
3140
3141           if (!are_addresses_set
3142               && !has_relro
3143               && aligned_addr != addr
3144               && !parameters->incremental())
3145             {
3146               uint64_t first_off = (common_pagesize
3147                                     - (aligned_addr
3148                                        & (common_pagesize - 1)));
3149               uint64_t last_off = new_addr & (common_pagesize - 1);
3150               if (first_off > 0
3151                   && last_off > 0
3152                   && ((aligned_addr & ~ (common_pagesize - 1))
3153                       != (new_addr & ~ (common_pagesize - 1)))
3154                   && first_off + last_off <= common_pagesize)
3155                 {
3156                   *pshndx = shndx_hold;
3157                   addr = align_address(aligned_addr, common_pagesize);
3158                   addr = align_address(addr, (*p)->maximum_alignment());
3159                   off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3160                   off = align_file_offset(off, addr, abi_pagesize);
3161
3162                   increase_relro = this->increase_relro_;
3163                   if (this->script_options_->saw_sections_clause())
3164                     increase_relro = 0;
3165                   has_relro = false;
3166
3167                   new_addr = (*p)->set_section_addresses(this, true, addr,
3168                                                          &increase_relro,
3169                                                          &has_relro,
3170                                                          &off, pshndx);
3171                 }
3172             }
3173
3174           addr = new_addr;
3175
3176           // Implement --check-sections.  We know that the segments
3177           // are sorted by LMA.
3178           if (check_sections && last_load_segment != NULL)
3179             {
3180               gold_assert(last_load_segment->paddr() <= (*p)->paddr());
3181               if (last_load_segment->paddr() + last_load_segment->memsz()
3182                   > (*p)->paddr())
3183                 {
3184                   unsigned long long lb1 = last_load_segment->paddr();
3185                   unsigned long long le1 = lb1 + last_load_segment->memsz();
3186                   unsigned long long lb2 = (*p)->paddr();
3187                   unsigned long long le2 = lb2 + (*p)->memsz();
3188                   gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3189                                "[0x%llx -> 0x%llx]"),
3190                              lb1, le1, lb2, le2);
3191                 }
3192             }
3193           last_load_segment = *p;
3194         }
3195     }
3196
3197   // Handle the non-PT_LOAD segments, setting their offsets from their
3198   // section's offsets.
3199   for (Segment_list::iterator p = this->segment_list_.begin();
3200        p != this->segment_list_.end();
3201        ++p)
3202     {
3203       if ((*p)->type() != elfcpp::PT_LOAD)
3204         (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO
3205                          ? increase_relro
3206                          : 0);
3207     }
3208
3209   // Set the TLS offsets for each section in the PT_TLS segment.
3210   if (this->tls_segment_ != NULL)
3211     this->tls_segment_->set_tls_offsets();
3212
3213   return off;
3214 }
3215
3216 // Set the offsets of all the allocated sections when doing a
3217 // relocatable link.  This does the same jobs as set_segment_offsets,
3218 // only for a relocatable link.
3219
3220 off_t
3221 Layout::set_relocatable_section_offsets(Output_data* file_header,
3222                                         unsigned int* pshndx)
3223 {
3224   off_t off = 0;
3225
3226   file_header->set_address_and_file_offset(0, 0);
3227   off += file_header->data_size();
3228
3229   for (Section_list::iterator p = this->section_list_.begin();
3230        p != this->section_list_.end();
3231        ++p)
3232     {
3233       // We skip unallocated sections here, except that group sections
3234       // have to come first.
3235       if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
3236           && (*p)->type() != elfcpp::SHT_GROUP)
3237         continue;
3238
3239       off = align_address(off, (*p)->addralign());
3240
3241       // The linker script might have set the address.
3242       if (!(*p)->is_address_valid())
3243         (*p)->set_address(0);
3244       (*p)->set_file_offset(off);
3245       (*p)->finalize_data_size();
3246       off += (*p)->data_size();
3247
3248       (*p)->set_out_shndx(*pshndx);
3249       ++*pshndx;
3250     }
3251
3252   return off;
3253 }
3254
3255 // Set the file offset of all the sections not associated with a
3256 // segment.
3257
3258 off_t
3259 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
3260 {
3261   off_t startoff = off;
3262   off_t maxoff = off;
3263
3264   for (Section_list::iterator p = this->unattached_section_list_.begin();
3265        p != this->unattached_section_list_.end();
3266        ++p)
3267     {
3268       // The symtab section is handled in create_symtab_sections.
3269       if (*p == this->symtab_section_)
3270         continue;
3271
3272       // If we've already set the data size, don't set it again.
3273       if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
3274         continue;
3275
3276       if (pass == BEFORE_INPUT_SECTIONS_PASS
3277           && (*p)->requires_postprocessing())
3278         {
3279           (*p)->create_postprocessing_buffer();
3280           this->any_postprocessing_sections_ = true;
3281         }
3282
3283       if (pass == BEFORE_INPUT_SECTIONS_PASS
3284           && (*p)->after_input_sections())
3285         continue;
3286       else if (pass == POSTPROCESSING_SECTIONS_PASS
3287                && (!(*p)->after_input_sections()
3288                    || (*p)->type() == elfcpp::SHT_STRTAB))
3289         continue;
3290       else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3291                && (!(*p)->after_input_sections()
3292                    || (*p)->type() != elfcpp::SHT_STRTAB))
3293         continue;
3294
3295       if (!parameters->incremental_update())
3296         {
3297           off = align_address(off, (*p)->addralign());
3298           (*p)->set_file_offset(off);
3299           (*p)->finalize_data_size();
3300         }
3301       else
3302         {
3303           // Incremental update: allocate file space from free list.
3304           (*p)->pre_finalize_data_size();
3305           off_t current_size = (*p)->current_data_size();
3306           off = this->allocate(current_size, (*p)->addralign(), startoff);
3307           if (off == -1)
3308             {
3309               if (is_debugging_enabled(DEBUG_INCREMENTAL))
3310                 this->free_list_.dump();
3311               gold_assert((*p)->output_section() != NULL);
3312               gold_fallback(_("out of patch space for section %s; "
3313                               "relink with --incremental-full"),
3314                             (*p)->output_section()->name());
3315             }
3316           (*p)->set_file_offset(off);
3317           (*p)->finalize_data_size();
3318           if ((*p)->data_size() > current_size)
3319             {
3320               gold_assert((*p)->output_section() != NULL);
3321               gold_fallback(_("%s: section changed size; "
3322                               "relink with --incremental-full"),
3323                             (*p)->output_section()->name());
3324             }
3325           gold_debug(DEBUG_INCREMENTAL,
3326                      "set_section_offsets: %08lx %08lx %s",
3327                      static_cast<long>(off),
3328                      static_cast<long>((*p)->data_size()),
3329                      ((*p)->output_section() != NULL
3330                       ? (*p)->output_section()->name() : "(special)"));
3331         }
3332
3333       off += (*p)->data_size();
3334       if (off > maxoff)
3335         maxoff = off;
3336
3337       // At this point the name must be set.
3338       if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
3339         this->namepool_.add((*p)->name(), false, NULL);
3340     }
3341   return maxoff;
3342 }
3343
3344 // Set the section indexes of all the sections not associated with a
3345 // segment.
3346
3347 unsigned int
3348 Layout::set_section_indexes(unsigned int shndx)
3349 {
3350   for (Section_list::iterator p = this->unattached_section_list_.begin();
3351        p != this->unattached_section_list_.end();
3352        ++p)
3353     {
3354       if (!(*p)->has_out_shndx())
3355         {
3356           (*p)->set_out_shndx(shndx);
3357           ++shndx;
3358         }
3359     }
3360   return shndx;
3361 }
3362
3363 // Set the section addresses according to the linker script.  This is
3364 // only called when we see a SECTIONS clause.  This returns the
3365 // program segment which should hold the file header and segment
3366 // headers, if any.  It will return NULL if they should not be in a
3367 // segment.
3368
3369 Output_segment*
3370 Layout::set_section_addresses_from_script(Symbol_table* symtab)
3371 {
3372   Script_sections* ss = this->script_options_->script_sections();
3373   gold_assert(ss->saw_sections_clause());
3374   return this->script_options_->set_section_addresses(symtab, this);
3375 }
3376
3377 // Place the orphan sections in the linker script.
3378
3379 void
3380 Layout::place_orphan_sections_in_script()
3381 {
3382   Script_sections* ss = this->script_options_->script_sections();
3383   gold_assert(ss->saw_sections_clause());
3384
3385   // Place each orphaned output section in the script.
3386   for (Section_list::iterator p = this->section_list_.begin();
3387        p != this->section_list_.end();
3388        ++p)
3389     {
3390       if (!(*p)->found_in_sections_clause())
3391         ss->place_orphan(*p);
3392     }
3393 }
3394
3395 // Count the local symbols in the regular symbol table and the dynamic
3396 // symbol table, and build the respective string pools.
3397
3398 void
3399 Layout::count_local_symbols(const Task* task,
3400                             const Input_objects* input_objects)
3401 {
3402   // First, figure out an upper bound on the number of symbols we'll
3403   // be inserting into each pool.  This helps us create the pools with
3404   // the right size, to avoid unnecessary hashtable resizing.
3405   unsigned int symbol_count = 0;
3406   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3407        p != input_objects->relobj_end();
3408        ++p)
3409     symbol_count += (*p)->local_symbol_count();
3410
3411   // Go from "upper bound" to "estimate."  We overcount for two
3412   // reasons: we double-count symbols that occur in more than one
3413   // object file, and we count symbols that are dropped from the
3414   // output.  Add it all together and assume we overcount by 100%.
3415   symbol_count /= 2;
3416
3417   // We assume all symbols will go into both the sympool and dynpool.
3418   this->sympool_.reserve(symbol_count);
3419   this->dynpool_.reserve(symbol_count);
3420
3421   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3422        p != input_objects->relobj_end();
3423        ++p)
3424     {
3425       Task_lock_obj<Object> tlo(task, *p);
3426       (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
3427     }
3428 }
3429
3430 // Create the symbol table sections.  Here we also set the final
3431 // values of the symbols.  At this point all the loadable sections are
3432 // fully laid out.  SHNUM is the number of sections so far.
3433
3434 void
3435 Layout::create_symtab_sections(const Input_objects* input_objects,
3436                                Symbol_table* symtab,
3437                                unsigned int shnum,
3438                                off_t* poff)
3439 {
3440   int symsize;
3441   unsigned int align;
3442   if (parameters->target().get_size() == 32)
3443     {
3444       symsize = elfcpp::Elf_sizes<32>::sym_size;
3445       align = 4;
3446     }
3447   else if (parameters->target().get_size() == 64)
3448     {
3449       symsize = elfcpp::Elf_sizes<64>::sym_size;
3450       align = 8;
3451     }
3452   else
3453     gold_unreachable();
3454
3455   // Compute file offsets relative to the start of the symtab section.
3456   off_t off = 0;
3457
3458   // Save space for the dummy symbol at the start of the section.  We
3459   // never bother to write this out--it will just be left as zero.
3460   off += symsize;
3461   unsigned int local_symbol_index = 1;
3462
3463   // Add STT_SECTION symbols for each Output section which needs one.
3464   for (Section_list::iterator p = this->section_list_.begin();
3465        p != this->section_list_.end();
3466        ++p)
3467     {
3468       if (!(*p)->needs_symtab_index())
3469         (*p)->set_symtab_index(-1U);
3470       else
3471         {
3472           (*p)->set_symtab_index(local_symbol_index);
3473           ++local_symbol_index;
3474           off += symsize;
3475         }
3476     }
3477
3478   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3479        p != input_objects->relobj_end();
3480        ++p)
3481     {
3482       unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
3483                                                         off, symtab);
3484       off += (index - local_symbol_index) * symsize;
3485       local_symbol_index = index;
3486     }
3487
3488   unsigned int local_symcount = local_symbol_index;
3489   gold_assert(static_cast<off_t>(local_symcount * symsize) == off);
3490
3491   off_t dynoff;
3492   size_t dyn_global_index;
3493   size_t dyncount;
3494   if (this->dynsym_section_ == NULL)
3495     {
3496       dynoff = 0;
3497       dyn_global_index = 0;
3498       dyncount = 0;
3499     }
3500   else
3501     {
3502       dyn_global_index = this->dynsym_section_->info();
3503       off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
3504       dynoff = this->dynsym_section_->offset() + locsize;
3505       dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
3506       gold_assert(static_cast<off_t>(dyncount * symsize)
3507                   == this->dynsym_section_->data_size() - locsize);
3508     }
3509
3510   off_t global_off = off;
3511   off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
3512                          &this->sympool_, &local_symcount);
3513
3514   if (!parameters->options().strip_all())
3515     {
3516       this->sympool_.set_string_offsets();
3517
3518       const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
3519       Output_section* osymtab = this->make_output_section(symtab_name,
3520                                                           elfcpp::SHT_SYMTAB,
3521                                                           0, ORDER_INVALID,
3522                                                           false);
3523       this->symtab_section_ = osymtab;
3524
3525       Output_section_data* pos = new Output_data_fixed_space(off, align,
3526                                                              "** symtab");
3527       osymtab->add_output_section_data(pos);
3528
3529       // We generate a .symtab_shndx section if we have more than
3530       // SHN_LORESERVE sections.  Technically it is possible that we
3531       // don't need one, because it is possible that there are no
3532       // symbols in any of sections with indexes larger than
3533       // SHN_LORESERVE.  That is probably unusual, though, and it is
3534       // easier to always create one than to compute section indexes
3535       // twice (once here, once when writing out the symbols).
3536       if (shnum >= elfcpp::SHN_LORESERVE)
3537         {
3538           const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
3539                                                                false, NULL);
3540           Output_section* osymtab_xindex =
3541             this->make_output_section(symtab_xindex_name,
3542                                       elfcpp::SHT_SYMTAB_SHNDX, 0,
3543                                       ORDER_INVALID, false);
3544
3545           size_t symcount = off / symsize;
3546           this->symtab_xindex_ = new Output_symtab_xindex(symcount);
3547
3548           osymtab_xindex->add_output_section_data(this->symtab_xindex_);
3549
3550           osymtab_xindex->set_link_section(osymtab);
3551           osymtab_xindex->set_addralign(4);
3552           osymtab_xindex->set_entsize(4);
3553
3554           osymtab_xindex->set_after_input_sections();
3555
3556           // This tells the driver code to wait until the symbol table
3557           // has written out before writing out the postprocessing
3558           // sections, including the .symtab_shndx section.
3559           this->any_postprocessing_sections_ = true;
3560         }
3561
3562       const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
3563       Output_section* ostrtab = this->make_output_section(strtab_name,
3564                                                           elfcpp::SHT_STRTAB,
3565                                                           0, ORDER_INVALID,
3566                                                           false);
3567
3568       Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
3569       ostrtab->add_output_section_data(pstr);
3570
3571       off_t symtab_off;
3572       if (!parameters->incremental_update())
3573         symtab_off = align_address(*poff, align);
3574       else
3575         {
3576           symtab_off = this->allocate(off, align, *poff);
3577           if (off == -1)
3578             gold_fallback(_("out of patch space for symbol table; "
3579                             "relink with --incremental-full"));
3580           gold_debug(DEBUG_INCREMENTAL,
3581                      "create_symtab_sections: %08lx %08lx .symtab",
3582                      static_cast<long>(symtab_off),
3583                      static_cast<long>(off));
3584         }
3585
3586       symtab->set_file_offset(symtab_off + global_off);
3587       osymtab->set_file_offset(symtab_off);
3588       osymtab->finalize_data_size();
3589       osymtab->set_link_section(ostrtab);
3590       osymtab->set_info(local_symcount);
3591       osymtab->set_entsize(symsize);
3592
3593       if (symtab_off + off > *poff)
3594         *poff = symtab_off + off;
3595     }
3596 }
3597
3598 // Create the .shstrtab section, which holds the names of the
3599 // sections.  At the time this is called, we have created all the
3600 // output sections except .shstrtab itself.
3601
3602 Output_section*
3603 Layout::create_shstrtab()
3604 {
3605   // FIXME: We don't need to create a .shstrtab section if we are
3606   // stripping everything.
3607
3608   const char* name = this->namepool_.add(".shstrtab", false, NULL);
3609
3610   Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0,
3611                                                  ORDER_INVALID, false);
3612
3613   if (strcmp(parameters->options().compress_debug_sections(), "none") != 0)
3614     {
3615       // We can't write out this section until we've set all the
3616       // section names, and we don't set the names of compressed
3617       // output sections until relocations are complete.  FIXME: With
3618       // the current names we use, this is unnecessary.
3619       os->set_after_input_sections();
3620     }
3621
3622   Output_section_data* posd = new Output_data_strtab(&this->namepool_);
3623   os->add_output_section_data(posd);
3624
3625   return os;
3626 }
3627
3628 // Create the section headers.  SIZE is 32 or 64.  OFF is the file
3629 // offset.
3630
3631 void
3632 Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
3633 {
3634   Output_section_headers* oshdrs;
3635   oshdrs = new Output_section_headers(this,
3636                                       &this->segment_list_,
3637                                       &this->section_list_,
3638                                       &this->unattached_section_list_,
3639                                       &this->namepool_,
3640                                       shstrtab_section);
3641   off_t off;
3642   if (!parameters->incremental_update())
3643     off = align_address(*poff, oshdrs->addralign());
3644   else
3645     {
3646       oshdrs->pre_finalize_data_size();
3647       off = this->allocate(oshdrs->data_size(), oshdrs->addralign(), *poff);
3648       if (off == -1)
3649           gold_fallback(_("out of patch space for section header table; "
3650                           "relink with --incremental-full"));
3651       gold_debug(DEBUG_INCREMENTAL,
3652                  "create_shdrs: %08lx %08lx (section header table)",
3653                  static_cast<long>(off),
3654                  static_cast<long>(off + oshdrs->data_size()));
3655     }
3656   oshdrs->set_address_and_file_offset(0, off);
3657   off += oshdrs->data_size();
3658   if (off > *poff)
3659     *poff = off;
3660   this->section_headers_ = oshdrs;
3661 }
3662
3663 // Count the allocated sections.
3664
3665 size_t
3666 Layout::allocated_output_section_count() const
3667 {
3668   size_t section_count = 0;
3669   for (Segment_list::const_iterator p = this->segment_list_.begin();
3670        p != this->segment_list_.end();
3671        ++p)
3672     section_count += (*p)->output_section_count();
3673   return section_count;
3674 }
3675
3676 // Create the dynamic symbol table.
3677
3678 void
3679 Layout::create_dynamic_symtab(const Input_objects* input_objects,
3680                               Symbol_table* symtab,
3681                               Output_section** pdynstr,
3682                               unsigned int* plocal_dynamic_count,
3683                               std::vector<Symbol*>* pdynamic_symbols,
3684                               Versions* pversions)
3685 {
3686   // Count all the symbols in the dynamic symbol table, and set the
3687   // dynamic symbol indexes.
3688
3689   // Skip symbol 0, which is always all zeroes.
3690   unsigned int index = 1;
3691
3692   // Add STT_SECTION symbols for each Output section which needs one.
3693   for (Section_list::iterator p = this->section_list_.begin();
3694        p != this->section_list_.end();
3695        ++p)
3696     {
3697       if (!(*p)->needs_dynsym_index())
3698         (*p)->set_dynsym_index(-1U);
3699       else
3700         {
3701           (*p)->set_dynsym_index(index);
3702           ++index;
3703         }
3704     }
3705
3706   // Count the local symbols that need to go in the dynamic symbol table,
3707   // and set the dynamic symbol indexes.
3708   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3709        p != input_objects->relobj_end();
3710        ++p)
3711     {
3712       unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
3713       index = new_index;
3714     }
3715
3716   unsigned int local_symcount = index;
3717   *plocal_dynamic_count = local_symcount;
3718
3719   index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
3720                                      &this->dynpool_, pversions);
3721
3722   int symsize;
3723   unsigned int align;
3724   const int size = parameters->target().get_size();
3725   if (size == 32)
3726     {
3727       symsize = elfcpp::Elf_sizes<32>::sym_size;
3728       align = 4;
3729     }
3730   else if (size == 64)
3731     {
3732       symsize = elfcpp::Elf_sizes<64>::sym_size;
3733       align = 8;
3734     }
3735   else
3736     gold_unreachable();
3737
3738   // Create the dynamic symbol table section.
3739
3740   Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
3741                                                        elfcpp::SHT_DYNSYM,
3742                                                        elfcpp::SHF_ALLOC,
3743                                                        false,
3744                                                        ORDER_DYNAMIC_LINKER,
3745                                                        false);
3746
3747   // Check for NULL as a linker script may discard .dynsym.
3748   if (dynsym != NULL)
3749     {
3750       Output_section_data* odata = new Output_data_fixed_space(index * symsize,
3751                                                                align,
3752                                                                "** dynsym");
3753       dynsym->add_output_section_data(odata);
3754
3755       dynsym->set_info(local_symcount);
3756       dynsym->set_entsize(symsize);
3757       dynsym->set_addralign(align);
3758
3759       this->dynsym_section_ = dynsym;
3760     }
3761
3762   Output_data_dynamic* const odyn = this->dynamic_data_;
3763   if (odyn != NULL)
3764     {
3765       odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
3766       odyn->add_constant(elfcpp::DT_SYMENT, symsize);
3767     }
3768
3769   // If there are more than SHN_LORESERVE allocated sections, we
3770   // create a .dynsym_shndx section.  It is possible that we don't
3771   // need one, because it is possible that there are no dynamic
3772   // symbols in any of the sections with indexes larger than
3773   // SHN_LORESERVE.  This is probably unusual, though, and at this
3774   // time we don't know the actual section indexes so it is
3775   // inconvenient to check.
3776   if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
3777     {
3778       Output_section* dynsym_xindex =
3779         this->choose_output_section(NULL, ".dynsym_shndx",
3780                                     elfcpp::SHT_SYMTAB_SHNDX,
3781                                     elfcpp::SHF_ALLOC,
3782                                     false, ORDER_DYNAMIC_LINKER, false);
3783
3784       if (dynsym_xindex != NULL)
3785         {
3786           this->dynsym_xindex_ = new Output_symtab_xindex(index);
3787
3788           dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
3789
3790           dynsym_xindex->set_link_section(dynsym);
3791           dynsym_xindex->set_addralign(4);
3792           dynsym_xindex->set_entsize(4);
3793
3794           dynsym_xindex->set_after_input_sections();
3795
3796           // This tells the driver code to wait until the symbol table
3797           // has written out before writing out the postprocessing
3798           // sections, including the .dynsym_shndx section.
3799           this->any_postprocessing_sections_ = true;
3800         }
3801     }
3802
3803   // Create the dynamic string table section.
3804
3805   Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
3806                                                        elfcpp::SHT_STRTAB,
3807                                                        elfcpp::SHF_ALLOC,
3808                                                        false,
3809                                                        ORDER_DYNAMIC_LINKER,
3810                                                        false);
3811
3812   if (dynstr != NULL)
3813     {
3814       Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
3815       dynstr->add_output_section_data(strdata);
3816
3817       if (dynsym != NULL)
3818         dynsym->set_link_section(dynstr);
3819       if (this->dynamic_section_ != NULL)
3820         this->dynamic_section_->set_link_section(dynstr);
3821
3822       if (odyn != NULL)
3823         {
3824           odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
3825           odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
3826         }
3827
3828       *pdynstr = dynstr;
3829     }
3830
3831   // Create the hash tables.
3832
3833   if (strcmp(parameters->options().hash_style(), "sysv") == 0
3834       || strcmp(parameters->options().hash_style(), "both") == 0)
3835     {
3836       unsigned char* phash;
3837       unsigned int hashlen;
3838       Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
3839                                     &phash, &hashlen);
3840
3841       Output_section* hashsec =
3842         this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH,
3843                                     elfcpp::SHF_ALLOC, false,
3844                                     ORDER_DYNAMIC_LINKER, false);
3845
3846       Output_section_data* hashdata = new Output_data_const_buffer(phash,
3847                                                                    hashlen,
3848                                                                    align,
3849                                                                    "** hash");
3850       if (hashsec != NULL && hashdata != NULL)
3851         hashsec->add_output_section_data(hashdata);
3852
3853       if (hashsec != NULL)
3854         {
3855           if (dynsym != NULL)
3856             hashsec->set_link_section(dynsym);
3857           hashsec->set_entsize(4);
3858         }
3859
3860       if (odyn != NULL)
3861         odyn->add_section_address(elfcpp::DT_HASH, hashsec);
3862     }
3863
3864   if (strcmp(parameters->options().hash_style(), "gnu") == 0
3865       || strcmp(parameters->options().hash_style(), "both") == 0)
3866     {
3867       unsigned char* phash;
3868       unsigned int hashlen;
3869       Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
3870                                     &phash, &hashlen);
3871
3872       Output_section* hashsec =
3873         this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH,
3874                                     elfcpp::SHF_ALLOC, false,
3875                                     ORDER_DYNAMIC_LINKER, false);
3876
3877       Output_section_data* hashdata = new Output_data_const_buffer(phash,
3878                                                                    hashlen,
3879                                                                    align,
3880                                                                    "** hash");
3881       if (hashsec != NULL && hashdata != NULL)
3882         hashsec->add_output_section_data(hashdata);
3883
3884       if (hashsec != NULL)
3885         {
3886           if (dynsym != NULL)
3887             hashsec->set_link_section(dynsym);
3888
3889           // For a 64-bit target, the entries in .gnu.hash do not have
3890           // a uniform size, so we only set the entry size for a
3891           // 32-bit target.
3892           if (parameters->target().get_size() == 32)
3893             hashsec->set_entsize(4);
3894
3895           if (odyn != NULL)
3896             odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
3897         }
3898     }
3899 }
3900
3901 // Assign offsets to each local portion of the dynamic symbol table.
3902
3903 void
3904 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
3905 {
3906   Output_section* dynsym = this->dynsym_section_;
3907   if (dynsym == NULL)
3908     return;
3909
3910   off_t off = dynsym->offset();
3911
3912   // Skip the dummy symbol at the start of the section.
3913   off += dynsym->entsize();
3914
3915   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3916        p != input_objects->relobj_end();
3917        ++p)
3918     {
3919       unsigned int count = (*p)->set_local_dynsym_offset(off);
3920       off += count * dynsym->entsize();
3921     }
3922 }
3923
3924 // Create the version sections.
3925
3926 void
3927 Layout::create_version_sections(const Versions* versions,
3928                                 const Symbol_table* symtab,
3929                                 unsigned int local_symcount,
3930                                 const std::vector<Symbol*>& dynamic_symbols,
3931                                 const Output_section* dynstr)
3932 {
3933   if (!versions->any_defs() && !versions->any_needs())
3934     return;
3935
3936   switch (parameters->size_and_endianness())
3937     {
3938 #ifdef HAVE_TARGET_32_LITTLE
3939     case Parameters::TARGET_32_LITTLE:
3940       this->sized_create_version_sections<32, false>(versions, symtab,
3941                                                      local_symcount,
3942                                                      dynamic_symbols, dynstr);
3943       break;
3944 #endif
3945 #ifdef HAVE_TARGET_32_BIG
3946     case Parameters::TARGET_32_BIG:
3947       this->sized_create_version_sections<32, true>(versions, symtab,
3948                                                     local_symcount,
3949                                                     dynamic_symbols, dynstr);
3950       break;
3951 #endif
3952 #ifdef HAVE_TARGET_64_LITTLE
3953     case Parameters::TARGET_64_LITTLE:
3954       this->sized_create_version_sections<64, false>(versions, symtab,
3955                                                      local_symcount,
3956                                                      dynamic_symbols, dynstr);
3957       break;
3958 #endif
3959 #ifdef HAVE_TARGET_64_BIG
3960     case Parameters::TARGET_64_BIG:
3961       this->sized_create_version_sections<64, true>(versions, symtab,
3962                                                     local_symcount,
3963                                                     dynamic_symbols, dynstr);
3964       break;
3965 #endif
3966     default:
3967       gold_unreachable();
3968     }
3969 }
3970
3971 // Create the version sections, sized version.
3972
3973 template<int size, bool big_endian>
3974 void
3975 Layout::sized_create_version_sections(
3976     const Versions* versions,
3977     const Symbol_table* symtab,
3978     unsigned int local_symcount,
3979     const std::vector<Symbol*>& dynamic_symbols,
3980     const Output_section* dynstr)
3981 {
3982   Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
3983                                                      elfcpp::SHT_GNU_versym,
3984                                                      elfcpp::SHF_ALLOC,
3985                                                      false,
3986                                                      ORDER_DYNAMIC_LINKER,
3987                                                      false);
3988
3989   // Check for NULL since a linker script may discard this section.
3990   if (vsec != NULL)
3991     {
3992       unsigned char* vbuf;
3993       unsigned int vsize;
3994       versions->symbol_section_contents<size, big_endian>(symtab,
3995                                                           &this->dynpool_,
3996                                                           local_symcount,
3997                                                           dynamic_symbols,
3998                                                           &vbuf, &vsize);
3999
4000       Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
4001                                                                 "** versions");
4002
4003       vsec->add_output_section_data(vdata);
4004       vsec->set_entsize(2);
4005       vsec->set_link_section(this->dynsym_section_);
4006     }
4007
4008   Output_data_dynamic* const odyn = this->dynamic_data_;
4009   if (odyn != NULL && vsec != NULL)
4010     odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
4011
4012   if (versions->any_defs())
4013     {
4014       Output_section* vdsec;
4015       vdsec = this->choose_output_section(NULL, ".gnu.version_d",
4016                                           elfcpp::SHT_GNU_verdef,
4017                                           elfcpp::SHF_ALLOC,
4018                                           false, ORDER_DYNAMIC_LINKER, false);
4019
4020       if (vdsec != NULL)
4021         {
4022           unsigned char* vdbuf;
4023           unsigned int vdsize;
4024           unsigned int vdentries;
4025           versions->def_section_contents<size, big_endian>(&this->dynpool_,
4026                                                            &vdbuf, &vdsize,
4027                                                            &vdentries);
4028
4029           Output_section_data* vddata =
4030             new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
4031
4032           vdsec->add_output_section_data(vddata);
4033           vdsec->set_link_section(dynstr);
4034           vdsec->set_info(vdentries);
4035
4036           if (odyn != NULL)
4037             {
4038               odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
4039               odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
4040             }
4041         }
4042     }
4043
4044   if (versions->any_needs())
4045     {
4046       Output_section* vnsec;
4047       vnsec = this->choose_output_section(NULL, ".gnu.version_r",
4048                                           elfcpp::SHT_GNU_verneed,
4049                                           elfcpp::SHF_ALLOC,
4050                                           false, ORDER_DYNAMIC_LINKER, false);
4051
4052       if (vnsec != NULL)
4053         {
4054           unsigned char* vnbuf;
4055           unsigned int vnsize;
4056           unsigned int vnentries;
4057           versions->need_section_contents<size, big_endian>(&this->dynpool_,
4058                                                             &vnbuf, &vnsize,
4059                                                             &vnentries);
4060
4061           Output_section_data* vndata =
4062             new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
4063
4064           vnsec->add_output_section_data(vndata);
4065           vnsec->set_link_section(dynstr);
4066           vnsec->set_info(vnentries);
4067
4068           if (odyn != NULL)
4069             {
4070               odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
4071               odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
4072             }
4073         }
4074     }
4075 }
4076
4077 // Create the .interp section and PT_INTERP segment.
4078
4079 void
4080 Layout::create_interp(const Target* target)
4081 {
4082   gold_assert(this->interp_segment_ == NULL);
4083
4084   const char* interp = parameters->options().dynamic_linker();
4085   if (interp == NULL)
4086     {
4087       interp = target->dynamic_linker();
4088       gold_assert(interp != NULL);
4089     }
4090
4091   size_t len = strlen(interp) + 1;
4092
4093   Output_section_data* odata = new Output_data_const(interp, len, 1);
4094
4095   Output_section* osec = this->choose_output_section(NULL, ".interp",
4096                                                      elfcpp::SHT_PROGBITS,
4097                                                      elfcpp::SHF_ALLOC,
4098                                                      false, ORDER_INTERP,
4099                                                      false);
4100   if (osec != NULL)
4101     osec->add_output_section_data(odata);
4102 }
4103
4104 // Add dynamic tags for the PLT and the dynamic relocs.  This is
4105 // called by the target-specific code.  This does nothing if not doing
4106 // a dynamic link.
4107
4108 // USE_REL is true for REL relocs rather than RELA relocs.
4109
4110 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
4111
4112 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
4113 // and we also set DT_PLTREL.  We use PLT_REL's output section, since
4114 // some targets have multiple reloc sections in PLT_REL.
4115
4116 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
4117 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.  Again we use the output
4118 // section.
4119
4120 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
4121 // executable.
4122
4123 void
4124 Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
4125                                 const Output_data* plt_rel,
4126                                 const Output_data_reloc_generic* dyn_rel,
4127                                 bool add_debug, bool dynrel_includes_plt)
4128 {
4129   Output_data_dynamic* odyn = this->dynamic_data_;
4130   if (odyn == NULL)
4131     return;
4132
4133   if (plt_got != NULL && plt_got->output_section() != NULL)
4134     odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got);
4135
4136   if (plt_rel != NULL && plt_rel->output_section() != NULL)
4137     {
4138       odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section());
4139       odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section());
4140       odyn->add_constant(elfcpp::DT_PLTREL,
4141                          use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA);
4142     }
4143
4144   if (dyn_rel != NULL && dyn_rel->output_section() != NULL)
4145     {
4146       odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
4147                                 dyn_rel->output_section());
4148       if (plt_rel != NULL
4149           && plt_rel->output_section() != NULL
4150           && dynrel_includes_plt)
4151         odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
4152                                dyn_rel->output_section(),
4153                                plt_rel->output_section());
4154       else
4155         odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
4156                                dyn_rel->output_section());
4157       const int size = parameters->target().get_size();
4158       elfcpp::DT rel_tag;
4159       int rel_size;
4160       if (use_rel)
4161         {
4162           rel_tag = elfcpp::DT_RELENT;
4163           if (size == 32)
4164             rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size;
4165           else if (size == 64)
4166             rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size;
4167           else
4168             gold_unreachable();
4169         }
4170       else
4171         {
4172           rel_tag = elfcpp::DT_RELAENT;
4173           if (size == 32)
4174             rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size;
4175           else if (size == 64)
4176             rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size;
4177           else
4178             gold_unreachable();
4179         }
4180       odyn->add_constant(rel_tag, rel_size);
4181
4182       if (parameters->options().combreloc())
4183         {
4184           size_t c = dyn_rel->relative_reloc_count();
4185           if (c > 0)
4186             odyn->add_constant((use_rel
4187                                 ? elfcpp::DT_RELCOUNT
4188                                 : elfcpp::DT_RELACOUNT),
4189                                c);
4190         }
4191     }
4192
4193   if (add_debug && !parameters->options().shared())
4194     {
4195       // The value of the DT_DEBUG tag is filled in by the dynamic
4196       // linker at run time, and used by the debugger.
4197       odyn->add_constant(elfcpp::DT_DEBUG, 0);
4198     }
4199 }
4200
4201 // Finish the .dynamic section and PT_DYNAMIC segment.
4202
4203 void
4204 Layout::finish_dynamic_section(const Input_objects* input_objects,
4205                                const Symbol_table* symtab)
4206 {
4207   if (!this->script_options_->saw_phdrs_clause()
4208       && this->dynamic_section_ != NULL)
4209     {
4210       Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
4211                                                        (elfcpp::PF_R
4212                                                         | elfcpp::PF_W));
4213       oseg->add_output_section_to_nonload(this->dynamic_section_,
4214                                           elfcpp::PF_R | elfcpp::PF_W);
4215     }
4216
4217   Output_data_dynamic* const odyn = this->dynamic_data_;
4218   if (odyn == NULL)
4219     return;
4220
4221   for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
4222        p != input_objects->dynobj_end();
4223        ++p)
4224     {
4225       if (!(*p)->is_needed() && (*p)->as_needed())
4226         {
4227           // This dynamic object was linked with --as-needed, but it
4228           // is not needed.
4229           continue;
4230         }
4231
4232       odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
4233     }
4234
4235   if (parameters->options().shared())
4236     {
4237       const char* soname = parameters->options().soname();
4238       if (soname != NULL)
4239         odyn->add_string(elfcpp::DT_SONAME, soname);
4240     }
4241
4242   Symbol* sym = symtab->lookup(parameters->options().init());
4243   if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4244     odyn->add_symbol(elfcpp::DT_INIT, sym);
4245
4246   sym = symtab->lookup(parameters->options().fini());
4247   if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4248     odyn->add_symbol(elfcpp::DT_FINI, sym);
4249
4250   // Look for .init_array, .preinit_array and .fini_array by checking
4251   // section types.
4252   for(Layout::Section_list::const_iterator p = this->section_list_.begin();
4253       p != this->section_list_.end();
4254       ++p)
4255     switch((*p)->type())
4256       {
4257       case elfcpp::SHT_FINI_ARRAY:
4258         odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p);
4259         odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p); 
4260         break;
4261       case elfcpp::SHT_INIT_ARRAY:
4262         odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p);
4263         odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p); 
4264         break;
4265       case elfcpp::SHT_PREINIT_ARRAY:
4266         odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p);
4267         odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p); 
4268         break;
4269       default:
4270         break;
4271       }
4272   
4273   // Add a DT_RPATH entry if needed.
4274   const General_options::Dir_list& rpath(parameters->options().rpath());
4275   if (!rpath.empty())
4276     {
4277       std::string rpath_val;
4278       for (General_options::Dir_list::const_iterator p = rpath.begin();
4279            p != rpath.end();
4280            ++p)
4281         {
4282           if (rpath_val.empty())
4283             rpath_val = p->name();
4284           else
4285             {
4286               // Eliminate duplicates.
4287               General_options::Dir_list::const_iterator q;
4288               for (q = rpath.begin(); q != p; ++q)
4289                 if (q->name() == p->name())
4290                   break;
4291               if (q == p)
4292                 {
4293                   rpath_val += ':';
4294                   rpath_val += p->name();
4295                 }
4296             }
4297         }
4298
4299       odyn->add_string(elfcpp::DT_RPATH, rpath_val);
4300       if (parameters->options().enable_new_dtags())
4301         odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
4302     }
4303
4304   // Look for text segments that have dynamic relocations.
4305   bool have_textrel = false;
4306   if (!this->script_options_->saw_sections_clause())
4307     {
4308       for (Segment_list::const_iterator p = this->segment_list_.begin();
4309            p != this->segment_list_.end();
4310            ++p)
4311         {
4312           if ((*p)->type() == elfcpp::PT_LOAD
4313               && ((*p)->flags() & elfcpp::PF_W) == 0
4314               && (*p)->has_dynamic_reloc())
4315             {
4316               have_textrel = true;
4317               break;
4318             }
4319         }
4320     }
4321   else
4322     {
4323       // We don't know the section -> segment mapping, so we are
4324       // conservative and just look for readonly sections with
4325       // relocations.  If those sections wind up in writable segments,
4326       // then we have created an unnecessary DT_TEXTREL entry.
4327       for (Section_list::const_iterator p = this->section_list_.begin();
4328            p != this->section_list_.end();
4329            ++p)
4330         {
4331           if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
4332               && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
4333               && (*p)->has_dynamic_reloc())
4334             {
4335               have_textrel = true;
4336               break;
4337             }
4338         }
4339     }
4340
4341   if (parameters->options().filter() != NULL)
4342     odyn->add_string(elfcpp::DT_FILTER, parameters->options().filter());
4343   if (parameters->options().any_auxiliary())
4344     {
4345       for (options::String_set::const_iterator p =
4346              parameters->options().auxiliary_begin();
4347            p != parameters->options().auxiliary_end();
4348            ++p)
4349         odyn->add_string(elfcpp::DT_AUXILIARY, *p);
4350     }
4351
4352   // Add a DT_FLAGS entry if necessary.
4353   unsigned int flags = 0;
4354   if (have_textrel)
4355     {
4356       // Add a DT_TEXTREL for compatibility with older loaders.
4357       odyn->add_constant(elfcpp::DT_TEXTREL, 0);
4358       flags |= elfcpp::DF_TEXTREL;
4359
4360       if (parameters->options().text())
4361         gold_error(_("read-only segment has dynamic relocations"));
4362       else if (parameters->options().warn_shared_textrel()
4363                && parameters->options().shared())
4364         gold_warning(_("shared library text segment is not shareable"));
4365     }
4366   if (parameters->options().shared() && this->has_static_tls())
4367     flags |= elfcpp::DF_STATIC_TLS;
4368   if (parameters->options().origin())
4369     flags |= elfcpp::DF_ORIGIN;
4370   if (parameters->options().Bsymbolic())
4371     {
4372       flags |= elfcpp::DF_SYMBOLIC;
4373       // Add DT_SYMBOLIC for compatibility with older loaders.
4374       odyn->add_constant(elfcpp::DT_SYMBOLIC, 0);
4375     }
4376   if (parameters->options().now())
4377     flags |= elfcpp::DF_BIND_NOW;
4378   if (flags != 0)
4379     odyn->add_constant(elfcpp::DT_FLAGS, flags);
4380
4381   flags = 0;
4382   if (parameters->options().initfirst())
4383     flags |= elfcpp::DF_1_INITFIRST;
4384   if (parameters->options().interpose())
4385     flags |= elfcpp::DF_1_INTERPOSE;
4386   if (parameters->options().loadfltr())
4387     flags |= elfcpp::DF_1_LOADFLTR;
4388   if (parameters->options().nodefaultlib())
4389     flags |= elfcpp::DF_1_NODEFLIB;
4390   if (parameters->options().nodelete())
4391     flags |= elfcpp::DF_1_NODELETE;
4392   if (parameters->options().nodlopen())
4393     flags |= elfcpp::DF_1_NOOPEN;
4394   if (parameters->options().nodump())
4395     flags |= elfcpp::DF_1_NODUMP;
4396   if (!parameters->options().shared())
4397     flags &= ~(elfcpp::DF_1_INITFIRST
4398                | elfcpp::DF_1_NODELETE
4399                | elfcpp::DF_1_NOOPEN);
4400   if (parameters->options().origin())
4401     flags |= elfcpp::DF_1_ORIGIN;
4402   if (parameters->options().now())
4403     flags |= elfcpp::DF_1_NOW;
4404   if (parameters->options().Bgroup())
4405     flags |= elfcpp::DF_1_GROUP;
4406   if (flags != 0)
4407     odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
4408 }
4409
4410 // Set the size of the _DYNAMIC symbol table to be the size of the
4411 // dynamic data.
4412
4413 void
4414 Layout::set_dynamic_symbol_size(const Symbol_table* symtab)
4415 {
4416   Output_data_dynamic* const odyn = this->dynamic_data_;
4417   if (odyn == NULL)
4418     return;
4419   odyn->finalize_data_size();
4420   if (this->dynamic_symbol_ == NULL)
4421     return;
4422   off_t data_size = odyn->data_size();
4423   const int size = parameters->target().get_size();
4424   if (size == 32)
4425     symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size);
4426   else if (size == 64)
4427     symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size);
4428   else
4429     gold_unreachable();
4430 }
4431
4432 // The mapping of input section name prefixes to output section names.
4433 // In some cases one prefix is itself a prefix of another prefix; in
4434 // such a case the longer prefix must come first.  These prefixes are
4435 // based on the GNU linker default ELF linker script.
4436
4437 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4438 const Layout::Section_name_mapping Layout::section_name_mapping[] =
4439 {
4440   MAPPING_INIT(".text.", ".text"),
4441   MAPPING_INIT(".rodata.", ".rodata"),
4442   MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
4443   MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
4444   MAPPING_INIT(".data.", ".data"),
4445   MAPPING_INIT(".bss.", ".bss"),
4446   MAPPING_INIT(".tdata.", ".tdata"),
4447   MAPPING_INIT(".tbss.", ".tbss"),
4448   MAPPING_INIT(".init_array.", ".init_array"),
4449   MAPPING_INIT(".fini_array.", ".fini_array"),
4450   MAPPING_INIT(".sdata.", ".sdata"),
4451   MAPPING_INIT(".sbss.", ".sbss"),
4452   // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4453   // differently depending on whether it is creating a shared library.
4454   MAPPING_INIT(".sdata2.", ".sdata"),
4455   MAPPING_INIT(".sbss2.", ".sbss"),
4456   MAPPING_INIT(".lrodata.", ".lrodata"),
4457   MAPPING_INIT(".ldata.", ".ldata"),
4458   MAPPING_INIT(".lbss.", ".lbss"),
4459   MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4460   MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4461   MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4462   MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4463   MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4464   MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4465   MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4466   MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4467   MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4468   MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4469   MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4470   MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4471   MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4472   MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4473   MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4474   MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
4475   MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
4476   MAPPING_INIT(".ARM.extab", ".ARM.extab"),
4477   MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
4478   MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
4479   MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
4480 };
4481 #undef MAPPING_INIT
4482
4483 const int Layout::section_name_mapping_count =
4484   (sizeof(Layout::section_name_mapping)
4485    / sizeof(Layout::section_name_mapping[0]));
4486
4487 // Choose the output section name to use given an input section name.
4488 // Set *PLEN to the length of the name.  *PLEN is initialized to the
4489 // length of NAME.
4490
4491 const char*
4492 Layout::output_section_name(const Relobj* relobj, const char* name,
4493                             size_t* plen)
4494 {
4495   // gcc 4.3 generates the following sorts of section names when it
4496   // needs a section name specific to a function:
4497   //   .text.FN
4498   //   .rodata.FN
4499   //   .sdata2.FN
4500   //   .data.FN
4501   //   .data.rel.FN
4502   //   .data.rel.local.FN
4503   //   .data.rel.ro.FN
4504   //   .data.rel.ro.local.FN
4505   //   .sdata.FN
4506   //   .bss.FN
4507   //   .sbss.FN
4508   //   .tdata.FN
4509   //   .tbss.FN
4510
4511   // The GNU linker maps all of those to the part before the .FN,
4512   // except that .data.rel.local.FN is mapped to .data, and
4513   // .data.rel.ro.local.FN is mapped to .data.rel.ro.  The sections
4514   // beginning with .data.rel.ro.local are grouped together.
4515
4516   // For an anonymous namespace, the string FN can contain a '.'.
4517
4518   // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
4519   // GNU linker maps to .rodata.
4520
4521   // The .data.rel.ro sections are used with -z relro.  The sections
4522   // are recognized by name.  We use the same names that the GNU
4523   // linker does for these sections.
4524
4525   // It is hard to handle this in a principled way, so we don't even
4526   // try.  We use a table of mappings.  If the input section name is
4527   // not found in the table, we simply use it as the output section
4528   // name.
4529
4530   const Section_name_mapping* psnm = section_name_mapping;
4531   for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
4532     {
4533       if (strncmp(name, psnm->from, psnm->fromlen) == 0)
4534         {
4535           *plen = psnm->tolen;
4536           return psnm->to;
4537         }
4538     }
4539
4540   // As an additional complication, .ctors sections are output in
4541   // either .ctors or .init_array sections, and .dtors sections are
4542   // output in either .dtors or .fini_array sections.
4543   if (is_prefix_of(".ctors.", name) || is_prefix_of(".dtors.", name))
4544     {
4545       if (parameters->options().ctors_in_init_array())
4546         {
4547           *plen = 11;
4548           return name[1] == 'c' ? ".init_array" : ".fini_array";
4549         }
4550       else
4551         {
4552           *plen = 6;
4553           return name[1] == 'c' ? ".ctors" : ".dtors";
4554         }
4555     }
4556   if (parameters->options().ctors_in_init_array()
4557       && (strcmp(name, ".ctors") == 0 || strcmp(name, ".dtors") == 0))
4558     {
4559       // To make .init_array/.fini_array work with gcc we must exclude
4560       // .ctors and .dtors sections from the crtbegin and crtend
4561       // files.
4562       if (relobj == NULL
4563           || (!Layout::match_file_name(relobj, "crtbegin")
4564               && !Layout::match_file_name(relobj, "crtend")))
4565         {
4566           *plen = 11;
4567           return name[1] == 'c' ? ".init_array" : ".fini_array";
4568         }
4569     }
4570
4571   return name;
4572 }
4573
4574 // Return true if RELOBJ is an input file whose base name matches
4575 // FILE_NAME.  The base name must have an extension of ".o", and must
4576 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o".  This is
4577 // to match crtbegin.o as well as crtbeginS.o without getting confused
4578 // by other possibilities.  Overall matching the file name this way is
4579 // a dreadful hack, but the GNU linker does it in order to better
4580 // support gcc, and we need to be compatible.
4581
4582 bool
4583 Layout::match_file_name(const Relobj* relobj, const char* match)
4584 {
4585   const std::string& file_name(relobj->name());
4586   const char* base_name = lbasename(file_name.c_str());
4587   size_t match_len = strlen(match);
4588   if (strncmp(base_name, match, match_len) != 0)
4589     return false;
4590   size_t base_len = strlen(base_name);
4591   if (base_len != match_len + 2 && base_len != match_len + 3)
4592     return false;
4593   return memcmp(base_name + base_len - 2, ".o", 2) == 0;
4594 }
4595
4596 // Check if a comdat group or .gnu.linkonce section with the given
4597 // NAME is selected for the link.  If there is already a section,
4598 // *KEPT_SECTION is set to point to the existing section and the
4599 // function returns false.  Otherwise, OBJECT, SHNDX, IS_COMDAT, and
4600 // IS_GROUP_NAME are recorded for this NAME in the layout object,
4601 // *KEPT_SECTION is set to the internal copy and the function returns
4602 // true.
4603
4604 bool
4605 Layout::find_or_add_kept_section(const std::string& name,
4606                                  Relobj* object,
4607                                  unsigned int shndx,
4608                                  bool is_comdat,
4609                                  bool is_group_name,
4610                                  Kept_section** kept_section)
4611 {
4612   // It's normal to see a couple of entries here, for the x86 thunk
4613   // sections.  If we see more than a few, we're linking a C++
4614   // program, and we resize to get more space to minimize rehashing.
4615   if (this->signatures_.size() > 4
4616       && !this->resized_signatures_)
4617     {
4618       reserve_unordered_map(&this->signatures_,
4619                             this->number_of_input_files_ * 64);
4620       this->resized_signatures_ = true;
4621     }
4622
4623   Kept_section candidate;
4624   std::pair<Signatures::iterator, bool> ins =
4625     this->signatures_.insert(std::make_pair(name, candidate));
4626
4627   if (kept_section != NULL)
4628     *kept_section = &ins.first->second;
4629   if (ins.second)
4630     {
4631       // This is the first time we've seen this signature.
4632       ins.first->second.set_object(object);
4633       ins.first->second.set_shndx(shndx);
4634       if (is_comdat)
4635         ins.first->second.set_is_comdat();
4636       if (is_group_name)
4637         ins.first->second.set_is_group_name();
4638       return true;
4639     }
4640
4641   // We have already seen this signature.
4642
4643   if (ins.first->second.is_group_name())
4644     {
4645       // We've already seen a real section group with this signature.
4646       // If the kept group is from a plugin object, and we're in the
4647       // replacement phase, accept the new one as a replacement.
4648       if (ins.first->second.object() == NULL
4649           && parameters->options().plugins()->in_replacement_phase())
4650         {
4651           ins.first->second.set_object(object);
4652           ins.first->second.set_shndx(shndx);
4653           return true;
4654         }
4655       return false;
4656     }
4657   else if (is_group_name)
4658     {
4659       // This is a real section group, and we've already seen a
4660       // linkonce section with this signature.  Record that we've seen
4661       // a section group, and don't include this section group.
4662       ins.first->second.set_is_group_name();
4663       return false;
4664     }
4665   else
4666     {
4667       // We've already seen a linkonce section and this is a linkonce
4668       // section.  These don't block each other--this may be the same
4669       // symbol name with different section types.
4670       return true;
4671     }
4672 }
4673
4674 // Store the allocated sections into the section list.
4675
4676 void
4677 Layout::get_allocated_sections(Section_list* section_list) const
4678 {
4679   for (Section_list::const_iterator p = this->section_list_.begin();
4680        p != this->section_list_.end();
4681        ++p)
4682     if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
4683       section_list->push_back(*p);
4684 }
4685
4686 // Create an output segment.
4687
4688 Output_segment*
4689 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
4690 {
4691   gold_assert(!parameters->options().relocatable());
4692   Output_segment* oseg = new Output_segment(type, flags);
4693   this->segment_list_.push_back(oseg);
4694
4695   if (type == elfcpp::PT_TLS)
4696     this->tls_segment_ = oseg;
4697   else if (type == elfcpp::PT_GNU_RELRO)
4698     this->relro_segment_ = oseg;
4699   else if (type == elfcpp::PT_INTERP)
4700     this->interp_segment_ = oseg;
4701
4702   return oseg;
4703 }
4704
4705 // Return the file offset of the normal symbol table.
4706
4707 off_t
4708 Layout::symtab_section_offset() const
4709 {
4710   if (this->symtab_section_ != NULL)
4711     return this->symtab_section_->offset();
4712   return 0;
4713 }
4714
4715 // Return the section index of the normal symbol table.  It may have
4716 // been stripped by the -s/--strip-all option.
4717
4718 unsigned int
4719 Layout::symtab_section_shndx() const
4720 {
4721   if (this->symtab_section_ != NULL)
4722     return this->symtab_section_->out_shndx();
4723   return 0;
4724 }
4725
4726 // Write out the Output_sections.  Most won't have anything to write,
4727 // since most of the data will come from input sections which are
4728 // handled elsewhere.  But some Output_sections do have Output_data.
4729
4730 void
4731 Layout::write_output_sections(Output_file* of) const
4732 {
4733   for (Section_list::const_iterator p = this->section_list_.begin();
4734        p != this->section_list_.end();
4735        ++p)
4736     {
4737       if (!(*p)->after_input_sections())
4738         (*p)->write(of);
4739     }
4740 }
4741
4742 // Write out data not associated with a section or the symbol table.
4743
4744 void
4745 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
4746 {
4747   if (!parameters->options().strip_all())
4748     {
4749       const Output_section* symtab_section = this->symtab_section_;
4750       for (Section_list::const_iterator p = this->section_list_.begin();
4751            p != this->section_list_.end();
4752            ++p)
4753         {
4754           if ((*p)->needs_symtab_index())
4755             {
4756               gold_assert(symtab_section != NULL);
4757               unsigned int index = (*p)->symtab_index();
4758               gold_assert(index > 0 && index != -1U);
4759               off_t off = (symtab_section->offset()
4760                            + index * symtab_section->entsize());
4761               symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
4762             }
4763         }
4764     }
4765
4766   const Output_section* dynsym_section = this->dynsym_section_;
4767   for (Section_list::const_iterator p = this->section_list_.begin();
4768        p != this->section_list_.end();
4769        ++p)
4770     {
4771       if ((*p)->needs_dynsym_index())
4772         {
4773           gold_assert(dynsym_section != NULL);
4774           unsigned int index = (*p)->dynsym_index();
4775           gold_assert(index > 0 && index != -1U);
4776           off_t off = (dynsym_section->offset()
4777                        + index * dynsym_section->entsize());
4778           symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
4779         }
4780     }
4781
4782   // Write out the Output_data which are not in an Output_section.
4783   for (Data_list::const_iterator p = this->special_output_list_.begin();
4784        p != this->special_output_list_.end();
4785        ++p)
4786     (*p)->write(of);
4787 }
4788
4789 // Write out the Output_sections which can only be written after the
4790 // input sections are complete.
4791
4792 void
4793 Layout::write_sections_after_input_sections(Output_file* of)
4794 {
4795   // Determine the final section offsets, and thus the final output
4796   // file size.  Note we finalize the .shstrab last, to allow the
4797   // after_input_section sections to modify their section-names before
4798   // writing.
4799   if (this->any_postprocessing_sections_)
4800     {
4801       off_t off = this->output_file_size_;
4802       off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
4803
4804       // Now that we've finalized the names, we can finalize the shstrab.
4805       off =
4806         this->set_section_offsets(off,
4807                                   STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
4808
4809       if (off > this->output_file_size_)
4810         {
4811           of->resize(off);
4812           this->output_file_size_ = off;
4813         }
4814     }
4815
4816   for (Section_list::const_iterator p = this->section_list_.begin();
4817        p != this->section_list_.end();
4818        ++p)
4819     {
4820       if ((*p)->after_input_sections())
4821         (*p)->write(of);
4822     }
4823
4824   this->section_headers_->write(of);
4825 }
4826
4827 // If the build ID requires computing a checksum, do so here, and
4828 // write it out.  We compute a checksum over the entire file because
4829 // that is simplest.
4830
4831 void
4832 Layout::write_build_id(Output_file* of) const
4833 {
4834   if (this->build_id_note_ == NULL)
4835     return;
4836
4837   const unsigned char* iv = of->get_input_view(0, this->output_file_size_);
4838
4839   unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
4840                                           this->build_id_note_->data_size());
4841
4842   const char* style = parameters->options().build_id();
4843   if (strcmp(style, "sha1") == 0)
4844     {
4845       sha1_ctx ctx;
4846       sha1_init_ctx(&ctx);
4847       sha1_process_bytes(iv, this->output_file_size_, &ctx);
4848       sha1_finish_ctx(&ctx, ov);
4849     }
4850   else if (strcmp(style, "md5") == 0)
4851     {
4852       md5_ctx ctx;
4853       md5_init_ctx(&ctx);
4854       md5_process_bytes(iv, this->output_file_size_, &ctx);
4855       md5_finish_ctx(&ctx, ov);
4856     }
4857   else
4858     gold_unreachable();
4859
4860   of->write_output_view(this->build_id_note_->offset(),
4861                         this->build_id_note_->data_size(),
4862                         ov);
4863
4864   of->free_input_view(0, this->output_file_size_, iv);
4865 }
4866
4867 // Write out a binary file.  This is called after the link is
4868 // complete.  IN is the temporary output file we used to generate the
4869 // ELF code.  We simply walk through the segments, read them from
4870 // their file offset in IN, and write them to their load address in
4871 // the output file.  FIXME: with a bit more work, we could support
4872 // S-records and/or Intel hex format here.
4873
4874 void
4875 Layout::write_binary(Output_file* in) const
4876 {
4877   gold_assert(parameters->options().oformat_enum()
4878               == General_options::OBJECT_FORMAT_BINARY);
4879
4880   // Get the size of the binary file.
4881   uint64_t max_load_address = 0;
4882   for (Segment_list::const_iterator p = this->segment_list_.begin();
4883        p != this->segment_list_.end();
4884        ++p)
4885     {
4886       if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
4887         {
4888           uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
4889           if (max_paddr > max_load_address)
4890             max_load_address = max_paddr;
4891         }
4892     }
4893
4894   Output_file out(parameters->options().output_file_name());
4895   out.open(max_load_address);
4896
4897   for (Segment_list::const_iterator p = this->segment_list_.begin();
4898        p != this->segment_list_.end();
4899        ++p)
4900     {
4901       if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
4902         {
4903           const unsigned char* vin = in->get_input_view((*p)->offset(),
4904                                                         (*p)->filesz());
4905           unsigned char* vout = out.get_output_view((*p)->paddr(),
4906                                                     (*p)->filesz());
4907           memcpy(vout, vin, (*p)->filesz());
4908           out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
4909           in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
4910         }
4911     }
4912
4913   out.close();
4914 }
4915
4916 // Print the output sections to the map file.
4917
4918 void
4919 Layout::print_to_mapfile(Mapfile* mapfile) const
4920 {
4921   for (Segment_list::const_iterator p = this->segment_list_.begin();
4922        p != this->segment_list_.end();
4923        ++p)
4924     (*p)->print_sections_to_mapfile(mapfile);
4925 }
4926
4927 // Print statistical information to stderr.  This is used for --stats.
4928
4929 void
4930 Layout::print_stats() const
4931 {
4932   this->namepool_.print_stats("section name pool");
4933   this->sympool_.print_stats("output symbol name pool");
4934   this->dynpool_.print_stats("dynamic name pool");
4935
4936   for (Section_list::const_iterator p = this->section_list_.begin();
4937        p != this->section_list_.end();
4938        ++p)
4939     (*p)->print_merge_stats();
4940 }
4941
4942 // Write_sections_task methods.
4943
4944 // We can always run this task.
4945
4946 Task_token*
4947 Write_sections_task::is_runnable()
4948 {
4949   return NULL;
4950 }
4951
4952 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
4953 // when finished.
4954
4955 void
4956 Write_sections_task::locks(Task_locker* tl)
4957 {
4958   tl->add(this, this->output_sections_blocker_);
4959   tl->add(this, this->final_blocker_);
4960 }
4961
4962 // Run the task--write out the data.
4963
4964 void
4965 Write_sections_task::run(Workqueue*)
4966 {
4967   this->layout_->write_output_sections(this->of_);
4968 }
4969
4970 // Write_data_task methods.
4971
4972 // We can always run this task.
4973
4974 Task_token*
4975 Write_data_task::is_runnable()
4976 {
4977   return NULL;
4978 }
4979
4980 // We need to unlock FINAL_BLOCKER when finished.
4981
4982 void
4983 Write_data_task::locks(Task_locker* tl)
4984 {
4985   tl->add(this, this->final_blocker_);
4986 }
4987
4988 // Run the task--write out the data.
4989
4990 void
4991 Write_data_task::run(Workqueue*)
4992 {
4993   this->layout_->write_data(this->symtab_, this->of_);
4994 }
4995
4996 // Write_symbols_task methods.
4997
4998 // We can always run this task.
4999
5000 Task_token*
5001 Write_symbols_task::is_runnable()
5002 {
5003   return NULL;
5004 }
5005
5006 // We need to unlock FINAL_BLOCKER when finished.
5007
5008 void
5009 Write_symbols_task::locks(Task_locker* tl)
5010 {
5011   tl->add(this, this->final_blocker_);
5012 }
5013
5014 // Run the task--write out the symbols.
5015
5016 void
5017 Write_symbols_task::run(Workqueue*)
5018 {
5019   this->symtab_->write_globals(this->sympool_, this->dynpool_,
5020                                this->layout_->symtab_xindex(),
5021                                this->layout_->dynsym_xindex(), this->of_);
5022 }
5023
5024 // Write_after_input_sections_task methods.
5025
5026 // We can only run this task after the input sections have completed.
5027
5028 Task_token*
5029 Write_after_input_sections_task::is_runnable()
5030 {
5031   if (this->input_sections_blocker_->is_blocked())
5032     return this->input_sections_blocker_;
5033   return NULL;
5034 }
5035
5036 // We need to unlock FINAL_BLOCKER when finished.
5037
5038 void
5039 Write_after_input_sections_task::locks(Task_locker* tl)
5040 {
5041   tl->add(this, this->final_blocker_);
5042 }
5043
5044 // Run the task.
5045
5046 void
5047 Write_after_input_sections_task::run(Workqueue*)
5048 {
5049   this->layout_->write_sections_after_input_sections(this->of_);
5050 }
5051
5052 // Close_task_runner methods.
5053
5054 // Run the task--close the file.
5055
5056 void
5057 Close_task_runner::run(Workqueue*, const Task*)
5058 {
5059   // If we need to compute a checksum for the BUILD if, we do so here.
5060   this->layout_->write_build_id(this->of_);
5061
5062   // If we've been asked to create a binary file, we do so here.
5063   if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
5064     this->layout_->write_binary(this->of_);
5065
5066   this->of_->close();
5067 }
5068
5069 // Instantiate the templates we need.  We could use the configure
5070 // script to restrict this to only the ones for implemented targets.
5071
5072 #ifdef HAVE_TARGET_32_LITTLE
5073 template
5074 Output_section*
5075 Layout::init_fixed_output_section<32, false>(
5076     const char* name,
5077     elfcpp::Shdr<32, false>& shdr);
5078 #endif
5079
5080 #ifdef HAVE_TARGET_32_BIG
5081 template
5082 Output_section*
5083 Layout::init_fixed_output_section<32, true>(
5084     const char* name,
5085     elfcpp::Shdr<32, true>& shdr);
5086 #endif
5087
5088 #ifdef HAVE_TARGET_64_LITTLE
5089 template
5090 Output_section*
5091 Layout::init_fixed_output_section<64, false>(
5092     const char* name,
5093     elfcpp::Shdr<64, false>& shdr);
5094 #endif
5095
5096 #ifdef HAVE_TARGET_64_BIG
5097 template
5098 Output_section*
5099 Layout::init_fixed_output_section<64, true>(
5100     const char* name,
5101     elfcpp::Shdr<64, true>& shdr);
5102 #endif
5103
5104 #ifdef HAVE_TARGET_32_LITTLE
5105 template
5106 Output_section*
5107 Layout::layout<32, false>(Sized_relobj_file<32, false>* object,
5108                           unsigned int shndx,
5109                           const char* name,
5110                           const elfcpp::Shdr<32, false>& shdr,
5111                           unsigned int, unsigned int, off_t*);
5112 #endif
5113
5114 #ifdef HAVE_TARGET_32_BIG
5115 template
5116 Output_section*
5117 Layout::layout<32, true>(Sized_relobj_file<32, true>* object,
5118                          unsigned int shndx,
5119                          const char* name,
5120                          const elfcpp::Shdr<32, true>& shdr,
5121                          unsigned int, unsigned int, off_t*);
5122 #endif
5123
5124 #ifdef HAVE_TARGET_64_LITTLE
5125 template
5126 Output_section*
5127 Layout::layout<64, false>(Sized_relobj_file<64, false>* object,
5128                           unsigned int shndx,
5129                           const char* name,
5130                           const elfcpp::Shdr<64, false>& shdr,
5131                           unsigned int, unsigned int, off_t*);
5132 #endif
5133
5134 #ifdef HAVE_TARGET_64_BIG
5135 template
5136 Output_section*
5137 Layout::layout<64, true>(Sized_relobj_file<64, true>* object,
5138                          unsigned int shndx,
5139                          const char* name,
5140                          const elfcpp::Shdr<64, true>& shdr,
5141                          unsigned int, unsigned int, off_t*);
5142 #endif
5143
5144 #ifdef HAVE_TARGET_32_LITTLE
5145 template
5146 Output_section*
5147 Layout::layout_reloc<32, false>(Sized_relobj_file<32, false>* object,
5148                                 unsigned int reloc_shndx,
5149                                 const elfcpp::Shdr<32, false>& shdr,
5150                                 Output_section* data_section,
5151                                 Relocatable_relocs* rr);
5152 #endif
5153
5154 #ifdef HAVE_TARGET_32_BIG
5155 template
5156 Output_section*
5157 Layout::layout_reloc<32, true>(Sized_relobj_file<32, true>* object,
5158                                unsigned int reloc_shndx,
5159                                const elfcpp::Shdr<32, true>& shdr,
5160                                Output_section* data_section,
5161                                Relocatable_relocs* rr);
5162 #endif
5163
5164 #ifdef HAVE_TARGET_64_LITTLE
5165 template
5166 Output_section*
5167 Layout::layout_reloc<64, false>(Sized_relobj_file<64, false>* object,
5168                                 unsigned int reloc_shndx,
5169                                 const elfcpp::Shdr<64, false>& shdr,
5170                                 Output_section* data_section,
5171                                 Relocatable_relocs* rr);
5172 #endif
5173
5174 #ifdef HAVE_TARGET_64_BIG
5175 template
5176 Output_section*
5177 Layout::layout_reloc<64, true>(Sized_relobj_file<64, true>* object,
5178                                unsigned int reloc_shndx,
5179                                const elfcpp::Shdr<64, true>& shdr,
5180                                Output_section* data_section,
5181                                Relocatable_relocs* rr);
5182 #endif
5183
5184 #ifdef HAVE_TARGET_32_LITTLE
5185 template
5186 void
5187 Layout::layout_group<32, false>(Symbol_table* symtab,
5188                                 Sized_relobj_file<32, false>* object,
5189                                 unsigned int,
5190                                 const char* group_section_name,
5191                                 const char* signature,
5192                                 const elfcpp::Shdr<32, false>& shdr,
5193                                 elfcpp::Elf_Word flags,
5194                                 std::vector<unsigned int>* shndxes);
5195 #endif
5196
5197 #ifdef HAVE_TARGET_32_BIG
5198 template
5199 void
5200 Layout::layout_group<32, true>(Symbol_table* symtab,
5201                                Sized_relobj_file<32, true>* object,
5202                                unsigned int,
5203                                const char* group_section_name,
5204                                const char* signature,
5205                                const elfcpp::Shdr<32, true>& shdr,
5206                                elfcpp::Elf_Word flags,
5207                                std::vector<unsigned int>* shndxes);
5208 #endif
5209
5210 #ifdef HAVE_TARGET_64_LITTLE
5211 template
5212 void
5213 Layout::layout_group<64, false>(Symbol_table* symtab,
5214                                 Sized_relobj_file<64, false>* object,
5215                                 unsigned int,
5216                                 const char* group_section_name,
5217                                 const char* signature,
5218                                 const elfcpp::Shdr<64, false>& shdr,
5219                                 elfcpp::Elf_Word flags,
5220                                 std::vector<unsigned int>* shndxes);
5221 #endif
5222
5223 #ifdef HAVE_TARGET_64_BIG
5224 template
5225 void
5226 Layout::layout_group<64, true>(Symbol_table* symtab,
5227                                Sized_relobj_file<64, true>* object,
5228                                unsigned int,
5229                                const char* group_section_name,
5230                                const char* signature,
5231                                const elfcpp::Shdr<64, true>& shdr,
5232                                elfcpp::Elf_Word flags,
5233                                std::vector<unsigned int>* shndxes);
5234 #endif
5235
5236 #ifdef HAVE_TARGET_32_LITTLE
5237 template
5238 Output_section*
5239 Layout::layout_eh_frame<32, false>(Sized_relobj_file<32, false>* object,
5240                                    const unsigned char* symbols,
5241                                    off_t symbols_size,
5242                                    const unsigned char* symbol_names,
5243                                    off_t symbol_names_size,
5244                                    unsigned int shndx,
5245                                    const elfcpp::Shdr<32, false>& shdr,
5246                                    unsigned int reloc_shndx,
5247                                    unsigned int reloc_type,
5248                                    off_t* off);
5249 #endif
5250
5251 #ifdef HAVE_TARGET_32_BIG
5252 template
5253 Output_section*
5254 Layout::layout_eh_frame<32, true>(Sized_relobj_file<32, true>* object,
5255                                   const unsigned char* symbols,
5256                                   off_t symbols_size,
5257                                   const unsigned char* symbol_names,
5258                                   off_t symbol_names_size,
5259                                   unsigned int shndx,
5260                                   const elfcpp::Shdr<32, true>& shdr,
5261                                   unsigned int reloc_shndx,
5262                                   unsigned int reloc_type,
5263                                   off_t* off);
5264 #endif
5265
5266 #ifdef HAVE_TARGET_64_LITTLE
5267 template
5268 Output_section*
5269 Layout::layout_eh_frame<64, false>(Sized_relobj_file<64, false>* object,
5270                                    const unsigned char* symbols,
5271                                    off_t symbols_size,
5272                                    const unsigned char* symbol_names,
5273                                    off_t symbol_names_size,
5274                                    unsigned int shndx,
5275                                    const elfcpp::Shdr<64, false>& shdr,
5276                                    unsigned int reloc_shndx,
5277                                    unsigned int reloc_type,
5278                                    off_t* off);
5279 #endif
5280
5281 #ifdef HAVE_TARGET_64_BIG
5282 template
5283 Output_section*
5284 Layout::layout_eh_frame<64, true>(Sized_relobj_file<64, true>* object,
5285                                   const unsigned char* symbols,
5286                                   off_t symbols_size,
5287                                   const unsigned char* symbol_names,
5288                                   off_t symbol_names_size,
5289                                   unsigned int shndx,
5290                                   const elfcpp::Shdr<64, true>& shdr,
5291                                   unsigned int reloc_shndx,
5292                                   unsigned int reloc_type,
5293                                   off_t* off);
5294 #endif
5295
5296 } // End namespace gold.