Add support for .note.gnu.property sections.
[external/binutils.git] / gold / layout.cc
1 // layout.cc -- lay out output file sections for gold
2
3 // Copyright (C) 2006-2018 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 #ifdef __MINGW32__
38 #include <windows.h>
39 #include <rpcdce.h>
40 #endif
41
42 #include "parameters.h"
43 #include "options.h"
44 #include "mapfile.h"
45 #include "script.h"
46 #include "script-sections.h"
47 #include "output.h"
48 #include "symtab.h"
49 #include "dynobj.h"
50 #include "ehframe.h"
51 #include "gdb-index.h"
52 #include "compressed_output.h"
53 #include "reduced_debug_output.h"
54 #include "object.h"
55 #include "reloc.h"
56 #include "descriptors.h"
57 #include "plugin.h"
58 #include "incremental.h"
59 #include "layout.h"
60
61 namespace gold
62 {
63
64 // Class Free_list.
65
66 // The total number of free lists used.
67 unsigned int Free_list::num_lists = 0;
68 // The total number of free list nodes used.
69 unsigned int Free_list::num_nodes = 0;
70 // The total number of calls to Free_list::remove.
71 unsigned int Free_list::num_removes = 0;
72 // The total number of nodes visited during calls to Free_list::remove.
73 unsigned int Free_list::num_remove_visits = 0;
74 // The total number of calls to Free_list::allocate.
75 unsigned int Free_list::num_allocates = 0;
76 // The total number of nodes visited during calls to Free_list::allocate.
77 unsigned int Free_list::num_allocate_visits = 0;
78
79 // Initialize the free list.  Creates a single free list node that
80 // describes the entire region of length LEN.  If EXTEND is true,
81 // allocate() is allowed to extend the region beyond its initial
82 // length.
83
84 void
85 Free_list::init(off_t len, bool extend)
86 {
87   this->list_.push_front(Free_list_node(0, len));
88   this->last_remove_ = this->list_.begin();
89   this->extend_ = extend;
90   this->length_ = len;
91   ++Free_list::num_lists;
92   ++Free_list::num_nodes;
93 }
94
95 // Remove a chunk from the free list.  Because we start with a single
96 // node that covers the entire section, and remove chunks from it one
97 // at a time, we do not need to coalesce chunks or handle cases that
98 // span more than one free node.  We expect to remove chunks from the
99 // free list in order, and we expect to have only a few chunks of free
100 // space left (corresponding to files that have changed since the last
101 // incremental link), so a simple linear list should provide sufficient
102 // performance.
103
104 void
105 Free_list::remove(off_t start, off_t end)
106 {
107   if (start == end)
108     return;
109   gold_assert(start < end);
110
111   ++Free_list::num_removes;
112
113   Iterator p = this->last_remove_;
114   if (p->start_ > start)
115     p = this->list_.begin();
116
117   for (; p != this->list_.end(); ++p)
118     {
119       ++Free_list::num_remove_visits;
120       // Find a node that wholly contains the indicated region.
121       if (p->start_ <= start && p->end_ >= end)
122         {
123           // Case 1: the indicated region spans the whole node.
124           // Add some fuzz to avoid creating tiny free chunks.
125           if (p->start_ + 3 >= start && p->end_ <= end + 3)
126             p = this->list_.erase(p);
127           // Case 2: remove a chunk from the start of the node.
128           else if (p->start_ + 3 >= start)
129             p->start_ = end;
130           // Case 3: remove a chunk from the end of the node.
131           else if (p->end_ <= end + 3)
132             p->end_ = start;
133           // Case 4: remove a chunk from the middle, and split
134           // the node into two.
135           else
136             {
137               Free_list_node newnode(p->start_, start);
138               p->start_ = end;
139               this->list_.insert(p, newnode);
140               ++Free_list::num_nodes;
141             }
142           this->last_remove_ = p;
143           return;
144         }
145     }
146
147   // Did not find a node containing the given chunk.  This could happen
148   // because a small chunk was already removed due to the fuzz.
149   gold_debug(DEBUG_INCREMENTAL,
150              "Free_list::remove(%d,%d) not found",
151              static_cast<int>(start), static_cast<int>(end));
152 }
153
154 // Allocate a chunk of size LEN from the free list.  Returns -1ULL
155 // if a sufficiently large chunk of free space is not found.
156 // We use a simple first-fit algorithm.
157
158 off_t
159 Free_list::allocate(off_t len, uint64_t align, off_t minoff)
160 {
161   gold_debug(DEBUG_INCREMENTAL,
162              "Free_list::allocate(%08lx, %d, %08lx)",
163              static_cast<long>(len), static_cast<int>(align),
164              static_cast<long>(minoff));
165   if (len == 0)
166     return align_address(minoff, align);
167
168   ++Free_list::num_allocates;
169
170   // We usually want to drop free chunks smaller than 4 bytes.
171   // If we need to guarantee a minimum hole size, though, we need
172   // to keep track of all free chunks.
173   const int fuzz = this->min_hole_ > 0 ? 0 : 3;
174
175   for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
176     {
177       ++Free_list::num_allocate_visits;
178       off_t start = p->start_ > minoff ? p->start_ : minoff;
179       start = align_address(start, align);
180       off_t end = start + len;
181       if (end > p->end_ && p->end_ == this->length_ && this->extend_)
182         {
183           this->length_ = end;
184           p->end_ = end;
185         }
186       if (end == p->end_ || (end <= p->end_ - this->min_hole_))
187         {
188           if (p->start_ + fuzz >= start && p->end_ <= end + fuzz)
189             this->list_.erase(p);
190           else if (p->start_ + fuzz >= start)
191             p->start_ = end;
192           else if (p->end_ <= end + fuzz)
193             p->end_ = start;
194           else
195             {
196               Free_list_node newnode(p->start_, start);
197               p->start_ = end;
198               this->list_.insert(p, newnode);
199               ++Free_list::num_nodes;
200             }
201           return start;
202         }
203     }
204   if (this->extend_)
205     {
206       off_t start = align_address(this->length_, align);
207       this->length_ = start + len;
208       return start;
209     }
210   return -1;
211 }
212
213 // Dump the free list (for debugging).
214 void
215 Free_list::dump()
216 {
217   gold_info("Free list:\n     start      end   length\n");
218   for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
219     gold_info("  %08lx %08lx %08lx", static_cast<long>(p->start_),
220               static_cast<long>(p->end_),
221               static_cast<long>(p->end_ - p->start_));
222 }
223
224 // Print the statistics for the free lists.
225 void
226 Free_list::print_stats()
227 {
228   fprintf(stderr, _("%s: total free lists: %u\n"),
229           program_name, Free_list::num_lists);
230   fprintf(stderr, _("%s: total free list nodes: %u\n"),
231           program_name, Free_list::num_nodes);
232   fprintf(stderr, _("%s: calls to Free_list::remove: %u\n"),
233           program_name, Free_list::num_removes);
234   fprintf(stderr, _("%s: nodes visited: %u\n"),
235           program_name, Free_list::num_remove_visits);
236   fprintf(stderr, _("%s: calls to Free_list::allocate: %u\n"),
237           program_name, Free_list::num_allocates);
238   fprintf(stderr, _("%s: nodes visited: %u\n"),
239           program_name, Free_list::num_allocate_visits);
240 }
241
242 // A Hash_task computes the MD5 checksum of an array of char.
243
244 class Hash_task : public Task
245 {
246  public:
247   Hash_task(Output_file* of,
248             size_t offset,
249             size_t size,
250             unsigned char* dst,
251             Task_token* final_blocker)
252     : of_(of), offset_(offset), size_(size), dst_(dst),
253       final_blocker_(final_blocker)
254   { }
255
256   void
257   run(Workqueue*)
258   {
259     const unsigned char* iv =
260         this->of_->get_input_view(this->offset_, this->size_);
261     md5_buffer(reinterpret_cast<const char*>(iv), this->size_, this->dst_);
262     this->of_->free_input_view(this->offset_, this->size_, iv);
263   }
264
265   Task_token*
266   is_runnable()
267   { return NULL; }
268
269   // Unblock FINAL_BLOCKER_ when done.
270   void
271   locks(Task_locker* tl)
272   { tl->add(this, this->final_blocker_); }
273
274   std::string
275   get_name() const
276   { return "Hash_task"; }
277
278  private:
279   Output_file* of_;
280   const size_t offset_;
281   const size_t size_;
282   unsigned char* const dst_;
283   Task_token* const final_blocker_;
284 };
285
286 // Layout::Relaxation_debug_check methods.
287
288 // Check that sections and special data are in reset states.
289 // We do not save states for Output_sections and special Output_data.
290 // So we check that they have not assigned any addresses or offsets.
291 // clean_up_after_relaxation simply resets their addresses and offsets.
292 void
293 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
294     const Layout::Section_list& sections,
295     const Layout::Data_list& special_outputs,
296     const Layout::Data_list& relax_outputs)
297 {
298   for(Layout::Section_list::const_iterator p = sections.begin();
299       p != sections.end();
300       ++p)
301     gold_assert((*p)->address_and_file_offset_have_reset_values());
302
303   for(Layout::Data_list::const_iterator p = special_outputs.begin();
304       p != special_outputs.end();
305       ++p)
306     gold_assert((*p)->address_and_file_offset_have_reset_values());
307
308   gold_assert(relax_outputs.empty());
309 }
310
311 // Save information of SECTIONS for checking later.
312
313 void
314 Layout::Relaxation_debug_check::read_sections(
315     const Layout::Section_list& sections)
316 {
317   for(Layout::Section_list::const_iterator p = sections.begin();
318       p != sections.end();
319       ++p)
320     {
321       Output_section* os = *p;
322       Section_info info;
323       info.output_section = os;
324       info.address = os->is_address_valid() ? os->address() : 0;
325       info.data_size = os->is_data_size_valid() ? os->data_size() : -1;
326       info.offset = os->is_offset_valid()? os->offset() : -1 ;
327       this->section_infos_.push_back(info);
328     }
329 }
330
331 // Verify SECTIONS using previously recorded information.
332
333 void
334 Layout::Relaxation_debug_check::verify_sections(
335     const Layout::Section_list& sections)
336 {
337   size_t i = 0;
338   for(Layout::Section_list::const_iterator p = sections.begin();
339       p != sections.end();
340       ++p, ++i)
341     {
342       Output_section* os = *p;
343       uint64_t address = os->is_address_valid() ? os->address() : 0;
344       off_t data_size = os->is_data_size_valid() ? os->data_size() : -1;
345       off_t offset = os->is_offset_valid()? os->offset() : -1 ;
346
347       if (i >= this->section_infos_.size())
348         {
349           gold_fatal("Section_info of %s missing.\n", os->name());
350         }
351       const Section_info& info = this->section_infos_[i];
352       if (os != info.output_section)
353         gold_fatal("Section order changed.  Expecting %s but see %s\n",
354                    info.output_section->name(), os->name());
355       if (address != info.address
356           || data_size != info.data_size
357           || offset != info.offset)
358         gold_fatal("Section %s changed.\n", os->name());
359     }
360 }
361
362 // Layout_task_runner methods.
363
364 // Lay out the sections.  This is called after all the input objects
365 // have been read.
366
367 void
368 Layout_task_runner::run(Workqueue* workqueue, const Task* task)
369 {
370   // See if any of the input definitions violate the One Definition Rule.
371   // TODO: if this is too slow, do this as a task, rather than inline.
372   this->symtab_->detect_odr_violations(task, this->options_.output_file_name());
373
374   Layout* layout = this->layout_;
375   off_t file_size = layout->finalize(this->input_objects_,
376                                      this->symtab_,
377                                      this->target_,
378                                      task);
379
380   // Now we know the final size of the output file and we know where
381   // each piece of information goes.
382
383   if (this->mapfile_ != NULL)
384     {
385       this->mapfile_->print_discarded_sections(this->input_objects_);
386       layout->print_to_mapfile(this->mapfile_);
387     }
388
389   Output_file* of;
390   if (layout->incremental_base() == NULL)
391     {
392       of = new Output_file(parameters->options().output_file_name());
393       if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
394         of->set_is_temporary();
395       of->open(file_size);
396     }
397   else
398     {
399       of = layout->incremental_base()->output_file();
400
401       // Apply the incremental relocations for symbols whose values
402       // have changed.  We do this before we resize the file and start
403       // writing anything else to it, so that we can read the old
404       // incremental information from the file before (possibly)
405       // overwriting it.
406       if (parameters->incremental_update())
407         layout->incremental_base()->apply_incremental_relocs(this->symtab_,
408                                                              this->layout_,
409                                                              of);
410
411       of->resize(file_size);
412     }
413
414   // Queue up the final set of tasks.
415   gold::queue_final_tasks(this->options_, this->input_objects_,
416                           this->symtab_, layout, workqueue, of);
417 }
418
419 // Layout methods.
420
421 Layout::Layout(int number_of_input_files, Script_options* script_options)
422   : number_of_input_files_(number_of_input_files),
423     script_options_(script_options),
424     namepool_(),
425     sympool_(),
426     dynpool_(),
427     signatures_(),
428     section_name_map_(),
429     segment_list_(),
430     section_list_(),
431     unattached_section_list_(),
432     special_output_list_(),
433     relax_output_list_(),
434     section_headers_(NULL),
435     tls_segment_(NULL),
436     relro_segment_(NULL),
437     interp_segment_(NULL),
438     increase_relro_(0),
439     symtab_section_(NULL),
440     symtab_xindex_(NULL),
441     dynsym_section_(NULL),
442     dynsym_xindex_(NULL),
443     dynamic_section_(NULL),
444     dynamic_symbol_(NULL),
445     dynamic_data_(NULL),
446     eh_frame_section_(NULL),
447     eh_frame_data_(NULL),
448     added_eh_frame_data_(false),
449     eh_frame_hdr_section_(NULL),
450     gdb_index_data_(NULL),
451     build_id_note_(NULL),
452     debug_abbrev_(NULL),
453     debug_info_(NULL),
454     group_signatures_(),
455     output_file_size_(-1),
456     have_added_input_section_(false),
457     sections_are_attached_(false),
458     input_requires_executable_stack_(false),
459     input_with_gnu_stack_note_(false),
460     input_without_gnu_stack_note_(false),
461     has_static_tls_(false),
462     any_postprocessing_sections_(false),
463     resized_signatures_(false),
464     have_stabstr_section_(false),
465     section_ordering_specified_(false),
466     unique_segment_for_sections_specified_(false),
467     incremental_inputs_(NULL),
468     record_output_section_data_from_script_(false),
469     script_output_section_data_list_(),
470     segment_states_(NULL),
471     relaxation_debug_check_(NULL),
472     section_order_map_(),
473     section_segment_map_(),
474     input_section_position_(),
475     input_section_glob_(),
476     incremental_base_(NULL),
477     free_list_(),
478     gnu_properties_()
479 {
480   // Make space for more than enough segments for a typical file.
481   // This is just for efficiency--it's OK if we wind up needing more.
482   this->segment_list_.reserve(12);
483
484   // We expect two unattached Output_data objects: the file header and
485   // the segment headers.
486   this->special_output_list_.reserve(2);
487
488   // Initialize structure needed for an incremental build.
489   if (parameters->incremental())
490     this->incremental_inputs_ = new Incremental_inputs;
491
492   // The section name pool is worth optimizing in all cases, because
493   // it is small, but there are often overlaps due to .rel sections.
494   this->namepool_.set_optimize();
495 }
496
497 // For incremental links, record the base file to be modified.
498
499 void
500 Layout::set_incremental_base(Incremental_binary* base)
501 {
502   this->incremental_base_ = base;
503   this->free_list_.init(base->output_file()->filesize(), true);
504 }
505
506 // Hash a key we use to look up an output section mapping.
507
508 size_t
509 Layout::Hash_key::operator()(const Layout::Key& k) const
510 {
511  return k.first + k.second.first + k.second.second;
512 }
513
514 // These are the debug sections that are actually used by gdb.
515 // Currently, we've checked versions of gdb up to and including 7.4.
516 // We only check the part of the name that follows ".debug_" or
517 // ".zdebug_".
518
519 static const char* gdb_sections[] =
520 {
521   "abbrev",
522   "addr",         // Fission extension
523   // "aranges",   // not used by gdb as of 7.4
524   "frame",
525   "gdb_scripts",
526   "info",
527   "types",
528   "line",
529   "loc",
530   "macinfo",
531   "macro",
532   // "pubnames",  // not used by gdb as of 7.4
533   // "pubtypes",  // not used by gdb as of 7.4
534   // "gnu_pubnames",  // Fission extension
535   // "gnu_pubtypes",  // Fission extension
536   "ranges",
537   "str",
538   "str_offsets",
539 };
540
541 // This is the minimum set of sections needed for line numbers.
542
543 static const char* lines_only_debug_sections[] =
544 {
545   "abbrev",
546   // "addr",      // Fission extension
547   // "aranges",   // not used by gdb as of 7.4
548   // "frame",
549   // "gdb_scripts",
550   "info",
551   // "types",
552   "line",
553   // "loc",
554   // "macinfo",
555   // "macro",
556   // "pubnames",  // not used by gdb as of 7.4
557   // "pubtypes",  // not used by gdb as of 7.4
558   // "gnu_pubnames",  // Fission extension
559   // "gnu_pubtypes",  // Fission extension
560   // "ranges",
561   "str",
562   "str_offsets",  // Fission extension
563 };
564
565 // These sections are the DWARF fast-lookup tables, and are not needed
566 // when building a .gdb_index section.
567
568 static const char* gdb_fast_lookup_sections[] =
569 {
570   "aranges",
571   "pubnames",
572   "gnu_pubnames",
573   "pubtypes",
574   "gnu_pubtypes",
575 };
576
577 // Returns whether the given debug section is in the list of
578 // debug-sections-used-by-some-version-of-gdb.  SUFFIX is the
579 // portion of the name following ".debug_" or ".zdebug_".
580
581 static inline bool
582 is_gdb_debug_section(const char* suffix)
583 {
584   // We can do this faster: binary search or a hashtable.  But why bother?
585   for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
586     if (strcmp(suffix, gdb_sections[i]) == 0)
587       return true;
588   return false;
589 }
590
591 // Returns whether the given section is needed for lines-only debugging.
592
593 static inline bool
594 is_lines_only_debug_section(const char* suffix)
595 {
596   // We can do this faster: binary search or a hashtable.  But why bother?
597   for (size_t i = 0;
598        i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections);
599        ++i)
600     if (strcmp(suffix, lines_only_debug_sections[i]) == 0)
601       return true;
602   return false;
603 }
604
605 // Returns whether the given section is a fast-lookup section that
606 // will not be needed when building a .gdb_index section.
607
608 static inline bool
609 is_gdb_fast_lookup_section(const char* suffix)
610 {
611   // We can do this faster: binary search or a hashtable.  But why bother?
612   for (size_t i = 0;
613        i < sizeof(gdb_fast_lookup_sections)/sizeof(*gdb_fast_lookup_sections);
614        ++i)
615     if (strcmp(suffix, gdb_fast_lookup_sections[i]) == 0)
616       return true;
617   return false;
618 }
619
620 // Sometimes we compress sections.  This is typically done for
621 // sections that are not part of normal program execution (such as
622 // .debug_* sections), and where the readers of these sections know
623 // how to deal with compressed sections.  This routine doesn't say for
624 // certain whether we'll compress -- it depends on commandline options
625 // as well -- just whether this section is a candidate for compression.
626 // (The Output_compressed_section class decides whether to compress
627 // a given section, and picks the name of the compressed section.)
628
629 static bool
630 is_compressible_debug_section(const char* secname)
631 {
632   return (is_prefix_of(".debug", secname));
633 }
634
635 // We may see compressed debug sections in input files.  Return TRUE
636 // if this is the name of a compressed debug section.
637
638 bool
639 is_compressed_debug_section(const char* secname)
640 {
641   return (is_prefix_of(".zdebug", secname));
642 }
643
644 std::string
645 corresponding_uncompressed_section_name(std::string secname)
646 {
647   gold_assert(secname[0] == '.' && secname[1] == 'z');
648   std::string ret(".");
649   ret.append(secname, 2, std::string::npos);
650   return ret;
651 }
652
653 // Whether to include this section in the link.
654
655 template<int size, bool big_endian>
656 bool
657 Layout::include_section(Sized_relobj_file<size, big_endian>*, const char* name,
658                         const elfcpp::Shdr<size, big_endian>& shdr)
659 {
660   if (!parameters->options().relocatable()
661       && (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE))
662     return false;
663
664   elfcpp::Elf_Word sh_type = shdr.get_sh_type();
665
666   if ((sh_type >= elfcpp::SHT_LOOS && sh_type <= elfcpp::SHT_HIOS)
667       || (sh_type >= elfcpp::SHT_LOPROC && sh_type <= elfcpp::SHT_HIPROC))
668     return parameters->target().should_include_section(sh_type);
669
670   switch (sh_type)
671     {
672     case elfcpp::SHT_NULL:
673     case elfcpp::SHT_SYMTAB:
674     case elfcpp::SHT_DYNSYM:
675     case elfcpp::SHT_HASH:
676     case elfcpp::SHT_DYNAMIC:
677     case elfcpp::SHT_SYMTAB_SHNDX:
678       return false;
679
680     case elfcpp::SHT_STRTAB:
681       // Discard the sections which have special meanings in the ELF
682       // ABI.  Keep others (e.g., .stabstr).  We could also do this by
683       // checking the sh_link fields of the appropriate sections.
684       return (strcmp(name, ".dynstr") != 0
685               && strcmp(name, ".strtab") != 0
686               && strcmp(name, ".shstrtab") != 0);
687
688     case elfcpp::SHT_RELA:
689     case elfcpp::SHT_REL:
690     case elfcpp::SHT_GROUP:
691       // If we are emitting relocations these should be handled
692       // elsewhere.
693       gold_assert(!parameters->options().relocatable());
694       return false;
695
696     case elfcpp::SHT_PROGBITS:
697       if (parameters->options().strip_debug()
698           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
699         {
700           if (is_debug_info_section(name))
701             return false;
702         }
703       if (parameters->options().strip_debug_non_line()
704           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
705         {
706           // Debugging sections can only be recognized by name.
707           if (is_prefix_of(".debug_", name)
708               && !is_lines_only_debug_section(name + 7))
709             return false;
710           if (is_prefix_of(".zdebug_", name)
711               && !is_lines_only_debug_section(name + 8))
712             return false;
713         }
714       if (parameters->options().strip_debug_gdb()
715           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
716         {
717           // Debugging sections can only be recognized by name.
718           if (is_prefix_of(".debug_", name)
719               && !is_gdb_debug_section(name + 7))
720             return false;
721           if (is_prefix_of(".zdebug_", name)
722               && !is_gdb_debug_section(name + 8))
723             return false;
724         }
725       if (parameters->options().gdb_index()
726           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
727         {
728           // When building .gdb_index, we can strip .debug_pubnames,
729           // .debug_pubtypes, and .debug_aranges sections.
730           if (is_prefix_of(".debug_", name)
731               && is_gdb_fast_lookup_section(name + 7))
732             return false;
733           if (is_prefix_of(".zdebug_", name)
734               && is_gdb_fast_lookup_section(name + 8))
735             return false;
736         }
737       if (parameters->options().strip_lto_sections()
738           && !parameters->options().relocatable()
739           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
740         {
741           // Ignore LTO sections containing intermediate code.
742           if (is_prefix_of(".gnu.lto_", name))
743             return false;
744         }
745       // The GNU linker strips .gnu_debuglink sections, so we do too.
746       // This is a feature used to keep debugging information in
747       // separate files.
748       if (strcmp(name, ".gnu_debuglink") == 0)
749         return false;
750       return true;
751
752     default:
753       return true;
754     }
755 }
756
757 // Return an output section named NAME, or NULL if there is none.
758
759 Output_section*
760 Layout::find_output_section(const char* name) const
761 {
762   for (Section_list::const_iterator p = this->section_list_.begin();
763        p != this->section_list_.end();
764        ++p)
765     if (strcmp((*p)->name(), name) == 0)
766       return *p;
767   return NULL;
768 }
769
770 // Return an output segment of type TYPE, with segment flags SET set
771 // and segment flags CLEAR clear.  Return NULL if there is none.
772
773 Output_segment*
774 Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
775                             elfcpp::Elf_Word clear) const
776 {
777   for (Segment_list::const_iterator p = this->segment_list_.begin();
778        p != this->segment_list_.end();
779        ++p)
780     if (static_cast<elfcpp::PT>((*p)->type()) == type
781         && ((*p)->flags() & set) == set
782         && ((*p)->flags() & clear) == 0)
783       return *p;
784   return NULL;
785 }
786
787 // When we put a .ctors or .dtors section with more than one word into
788 // a .init_array or .fini_array section, we need to reverse the words
789 // in the .ctors/.dtors section.  This is because .init_array executes
790 // constructors front to back, where .ctors executes them back to
791 // front, and vice-versa for .fini_array/.dtors.  Although we do want
792 // to remap .ctors/.dtors into .init_array/.fini_array because it can
793 // be more efficient, we don't want to change the order in which
794 // constructors/destructors are run.  This set just keeps track of
795 // these sections which need to be reversed.  It is only changed by
796 // Layout::layout.  It should be a private member of Layout, but that
797 // would require layout.h to #include object.h to get the definition
798 // of Section_id.
799 static Unordered_set<Section_id, Section_id_hash> ctors_sections_in_init_array;
800
801 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a
802 // .init_array/.fini_array section.
803
804 bool
805 Layout::is_ctors_in_init_array(Relobj* relobj, unsigned int shndx) const
806 {
807   return (ctors_sections_in_init_array.find(Section_id(relobj, shndx))
808           != ctors_sections_in_init_array.end());
809 }
810
811 // Return the output section to use for section NAME with type TYPE
812 // and section flags FLAGS.  NAME must be canonicalized in the string
813 // pool, and NAME_KEY is the key.  ORDER is where this should appear
814 // in the output sections.  IS_RELRO is true for a relro section.
815
816 Output_section*
817 Layout::get_output_section(const char* name, Stringpool::Key name_key,
818                            elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
819                            Output_section_order order, bool is_relro)
820 {
821   elfcpp::Elf_Word lookup_type = type;
822
823   // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and
824   // PREINIT_ARRAY like PROGBITS.  This ensures that we combine
825   // .init_array, .fini_array, and .preinit_array sections by name
826   // whatever their type in the input file.  We do this because the
827   // types are not always right in the input files.
828   if (lookup_type == elfcpp::SHT_INIT_ARRAY
829       || lookup_type == elfcpp::SHT_FINI_ARRAY
830       || lookup_type == elfcpp::SHT_PREINIT_ARRAY)
831     lookup_type = elfcpp::SHT_PROGBITS;
832
833   elfcpp::Elf_Xword lookup_flags = flags;
834
835   // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
836   // read-write with read-only sections.  Some other ELF linkers do
837   // not do this.  FIXME: Perhaps there should be an option
838   // controlling this.
839   lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
840
841   const Key key(name_key, std::make_pair(lookup_type, lookup_flags));
842   const std::pair<Key, Output_section*> v(key, NULL);
843   std::pair<Section_name_map::iterator, bool> ins(
844     this->section_name_map_.insert(v));
845
846   if (!ins.second)
847     return ins.first->second;
848   else
849     {
850       // This is the first time we've seen this name/type/flags
851       // combination.  For compatibility with the GNU linker, we
852       // combine sections with contents and zero flags with sections
853       // with non-zero flags.  This is a workaround for cases where
854       // assembler code forgets to set section flags.  FIXME: Perhaps
855       // there should be an option to control this.
856       Output_section* os = NULL;
857
858       if (lookup_type == elfcpp::SHT_PROGBITS)
859         {
860           if (flags == 0)
861             {
862               Output_section* same_name = this->find_output_section(name);
863               if (same_name != NULL
864                   && (same_name->type() == elfcpp::SHT_PROGBITS
865                       || same_name->type() == elfcpp::SHT_INIT_ARRAY
866                       || same_name->type() == elfcpp::SHT_FINI_ARRAY
867                       || same_name->type() == elfcpp::SHT_PREINIT_ARRAY)
868                   && (same_name->flags() & elfcpp::SHF_TLS) == 0)
869                 os = same_name;
870             }
871           else if ((flags & elfcpp::SHF_TLS) == 0)
872             {
873               elfcpp::Elf_Xword zero_flags = 0;
874               const Key zero_key(name_key, std::make_pair(lookup_type,
875                                                           zero_flags));
876               Section_name_map::iterator p =
877                   this->section_name_map_.find(zero_key);
878               if (p != this->section_name_map_.end())
879                 os = p->second;
880             }
881         }
882
883       if (os == NULL)
884         os = this->make_output_section(name, type, flags, order, is_relro);
885
886       ins.first->second = os;
887       return os;
888     }
889 }
890
891 // Returns TRUE iff NAME (an input section from RELOBJ) will
892 // be mapped to an output section that should be KEPT.
893
894 bool
895 Layout::keep_input_section(const Relobj* relobj, const char* name)
896 {
897   if (! this->script_options_->saw_sections_clause())
898     return false;
899
900   Script_sections* ss = this->script_options_->script_sections();
901   const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
902   Output_section** output_section_slot;
903   Script_sections::Section_type script_section_type;
904   bool keep;
905
906   name = ss->output_section_name(file_name, name, &output_section_slot,
907                                  &script_section_type, &keep, true);
908   return name != NULL && keep;
909 }
910
911 // Clear the input section flags that should not be copied to the
912 // output section.
913
914 elfcpp::Elf_Xword
915 Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags)
916 {
917   // Some flags in the input section should not be automatically
918   // copied to the output section.
919   input_section_flags &= ~ (elfcpp::SHF_INFO_LINK
920                             | elfcpp::SHF_GROUP
921                             | elfcpp::SHF_COMPRESSED
922                             | elfcpp::SHF_MERGE
923                             | elfcpp::SHF_STRINGS);
924
925   // We only clear the SHF_LINK_ORDER flag in for
926   // a non-relocatable link.
927   if (!parameters->options().relocatable())
928     input_section_flags &= ~elfcpp::SHF_LINK_ORDER;
929
930   return input_section_flags;
931 }
932
933 // Pick the output section to use for section NAME, in input file
934 // RELOBJ, with type TYPE and flags FLAGS.  RELOBJ may be NULL for a
935 // linker created section.  IS_INPUT_SECTION is true if we are
936 // choosing an output section for an input section found in a input
937 // file.  ORDER is where this section should appear in the output
938 // sections.  IS_RELRO is true for a relro section.  This will return
939 // NULL if the input section should be discarded.  MATCH_INPUT_SPEC
940 // is true if the section name should be matched against input specs
941 // in a linker script.
942
943 Output_section*
944 Layout::choose_output_section(const Relobj* relobj, const char* name,
945                               elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
946                               bool is_input_section, Output_section_order order,
947                               bool is_relro, bool is_reloc,
948                               bool match_input_spec)
949 {
950   // We should not see any input sections after we have attached
951   // sections to segments.
952   gold_assert(!is_input_section || !this->sections_are_attached_);
953
954   flags = this->get_output_section_flags(flags);
955
956   if (this->script_options_->saw_sections_clause() && !is_reloc)
957     {
958       // We are using a SECTIONS clause, so the output section is
959       // chosen based only on the name.
960
961       Script_sections* ss = this->script_options_->script_sections();
962       const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
963       Output_section** output_section_slot;
964       Script_sections::Section_type script_section_type;
965       const char* orig_name = name;
966       bool keep;
967       name = ss->output_section_name(file_name, name, &output_section_slot,
968                                      &script_section_type, &keep,
969                                      match_input_spec);
970
971       if (name == NULL)
972         {
973           gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' "
974                                      "because it is not allowed by the "
975                                      "SECTIONS clause of the linker script"),
976                      orig_name);
977           // The SECTIONS clause says to discard this input section.
978           return NULL;
979         }
980
981       // We can only handle script section types ST_NONE and ST_NOLOAD.
982       switch (script_section_type)
983         {
984         case Script_sections::ST_NONE:
985           break;
986         case Script_sections::ST_NOLOAD:
987           flags &= elfcpp::SHF_ALLOC;
988           break;
989         default:
990           gold_unreachable();
991         }
992
993       // If this is an orphan section--one not mentioned in the linker
994       // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
995       // default processing below.
996
997       if (output_section_slot != NULL)
998         {
999           if (*output_section_slot != NULL)
1000             {
1001               (*output_section_slot)->update_flags_for_input_section(flags);
1002               return *output_section_slot;
1003             }
1004
1005           // We don't put sections found in the linker script into
1006           // SECTION_NAME_MAP_.  That keeps us from getting confused
1007           // if an orphan section is mapped to a section with the same
1008           // name as one in the linker script.
1009
1010           name = this->namepool_.add(name, false, NULL);
1011
1012           Output_section* os = this->make_output_section(name, type, flags,
1013                                                          order, is_relro);
1014
1015           os->set_found_in_sections_clause();
1016
1017           // Special handling for NOLOAD sections.
1018           if (script_section_type == Script_sections::ST_NOLOAD)
1019             {
1020               os->set_is_noload();
1021
1022               // The constructor of Output_section sets addresses of non-ALLOC
1023               // sections to 0 by default.  We don't want that for NOLOAD
1024               // sections even if they have no SHF_ALLOC flag.
1025               if ((os->flags() & elfcpp::SHF_ALLOC) == 0
1026                   && os->is_address_valid())
1027                 {
1028                   gold_assert(os->address() == 0
1029                               && !os->is_offset_valid()
1030                               && !os->is_data_size_valid());
1031                   os->reset_address_and_file_offset();
1032                 }
1033             }
1034
1035           *output_section_slot = os;
1036           return os;
1037         }
1038     }
1039
1040   // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
1041
1042   size_t len = strlen(name);
1043   std::string uncompressed_name;
1044
1045   // Compressed debug sections should be mapped to the corresponding
1046   // uncompressed section.
1047   if (is_compressed_debug_section(name))
1048     {
1049       uncompressed_name =
1050           corresponding_uncompressed_section_name(std::string(name, len));
1051       name = uncompressed_name.c_str();
1052       len = uncompressed_name.length();
1053     }
1054
1055   // Turn NAME from the name of the input section into the name of the
1056   // output section.
1057   if (is_input_section
1058       && !this->script_options_->saw_sections_clause()
1059       && !parameters->options().relocatable())
1060     {
1061       const char *orig_name = name;
1062       name = parameters->target().output_section_name(relobj, name, &len);
1063       if (name == NULL)
1064         name = Layout::output_section_name(relobj, orig_name, &len);
1065     }
1066
1067   Stringpool::Key name_key;
1068   name = this->namepool_.add_with_length(name, len, true, &name_key);
1069
1070   // Find or make the output section.  The output section is selected
1071   // based on the section name, type, and flags.
1072   return this->get_output_section(name, name_key, type, flags, order, is_relro);
1073 }
1074
1075 // For incremental links, record the initial fixed layout of a section
1076 // from the base file, and return a pointer to the Output_section.
1077
1078 template<int size, bool big_endian>
1079 Output_section*
1080 Layout::init_fixed_output_section(const char* name,
1081                                   elfcpp::Shdr<size, big_endian>& shdr)
1082 {
1083   unsigned int sh_type = shdr.get_sh_type();
1084
1085   // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY,
1086   // PRE_INIT_ARRAY, and NOTE sections.
1087   // All others will be created from scratch and reallocated.
1088   if (!can_incremental_update(sh_type))
1089     return NULL;
1090
1091   // If we're generating a .gdb_index section, we need to regenerate
1092   // it from scratch.
1093   if (parameters->options().gdb_index()
1094       && sh_type == elfcpp::SHT_PROGBITS
1095       && strcmp(name, ".gdb_index") == 0)
1096     return NULL;
1097
1098   typename elfcpp::Elf_types<size>::Elf_Addr sh_addr = shdr.get_sh_addr();
1099   typename elfcpp::Elf_types<size>::Elf_Off sh_offset = shdr.get_sh_offset();
1100   typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
1101   typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
1102   typename elfcpp::Elf_types<size>::Elf_WXword sh_addralign =
1103       shdr.get_sh_addralign();
1104
1105   // Make the output section.
1106   Stringpool::Key name_key;
1107   name = this->namepool_.add(name, true, &name_key);
1108   Output_section* os = this->get_output_section(name, name_key, sh_type,
1109                                                 sh_flags, ORDER_INVALID, false);
1110   os->set_fixed_layout(sh_addr, sh_offset, sh_size, sh_addralign);
1111   if (sh_type != elfcpp::SHT_NOBITS)
1112     this->free_list_.remove(sh_offset, sh_offset + sh_size);
1113   return os;
1114 }
1115
1116 // Return the index by which an input section should be ordered.  This
1117 // is used to sort some .text sections, for compatibility with GNU ld.
1118
1119 int
1120 Layout::special_ordering_of_input_section(const char* name)
1121 {
1122   // The GNU linker has some special handling for some sections that
1123   // wind up in the .text section.  Sections that start with these
1124   // prefixes must appear first, and must appear in the order listed
1125   // here.
1126   static const char* const text_section_sort[] =
1127   {
1128     ".text.unlikely",
1129     ".text.exit",
1130     ".text.startup",
1131     ".text.hot"
1132   };
1133
1134   for (size_t i = 0;
1135        i < sizeof(text_section_sort) / sizeof(text_section_sort[0]);
1136        i++)
1137     if (is_prefix_of(text_section_sort[i], name))
1138       return i;
1139
1140   return -1;
1141 }
1142
1143 // Return the output section to use for input section SHNDX, with name
1144 // NAME, with header HEADER, from object OBJECT.  RELOC_SHNDX is the
1145 // index of a relocation section which applies to this section, or 0
1146 // if none, or -1U if more than one.  RELOC_TYPE is the type of the
1147 // relocation section if there is one.  Set *OFF to the offset of this
1148 // input section without the output section.  Return NULL if the
1149 // section should be discarded.  Set *OFF to -1 if the section
1150 // contents should not be written directly to the output file, but
1151 // will instead receive special handling.
1152
1153 template<int size, bool big_endian>
1154 Output_section*
1155 Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
1156                const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
1157                unsigned int sh_type, unsigned int reloc_shndx,
1158                unsigned int, off_t* off)
1159 {
1160   *off = 0;
1161
1162   if (!this->include_section(object, name, shdr))
1163     return NULL;
1164
1165   // In a relocatable link a grouped section must not be combined with
1166   // any other sections.
1167   Output_section* os;
1168   if (parameters->options().relocatable()
1169       && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
1170     {
1171       // Some flags in the input section should not be automatically
1172       // copied to the output section.
1173       elfcpp::Elf_Xword flags = (shdr.get_sh_flags()
1174                                  & ~ elfcpp::SHF_COMPRESSED);
1175       name = this->namepool_.add(name, true, NULL);
1176       os = this->make_output_section(name, sh_type, flags,
1177                                      ORDER_INVALID, false);
1178     }
1179   else
1180     {
1181       // All ".text.unlikely.*" sections can be moved to a unique
1182       // segment with --text-unlikely-segment option.
1183       bool text_unlikely_segment
1184           = (parameters->options().text_unlikely_segment()
1185              && is_prefix_of(".text.unlikely",
1186                              object->section_name(shndx).c_str()));
1187       if (text_unlikely_segment)
1188         {
1189           elfcpp::Elf_Xword flags
1190             = this->get_output_section_flags(shdr.get_sh_flags());
1191
1192           Stringpool::Key name_key;
1193           const char* os_name = this->namepool_.add(".text.unlikely", true,
1194                                                     &name_key);
1195           os = this->get_output_section(os_name, name_key, sh_type, flags,
1196                                         ORDER_INVALID, false);
1197           // Map this output section to a unique segment.  This is done to
1198           // separate "text" that is not likely to be executed from "text"
1199           // that is likely executed.
1200           os->set_is_unique_segment();
1201         }
1202       else
1203         {
1204           // Plugins can choose to place one or more subsets of sections in
1205           // unique segments and this is done by mapping these section subsets
1206           // to unique output sections.  Check if this section needs to be
1207           // remapped to a unique output section.
1208           Section_segment_map::iterator it
1209             = this->section_segment_map_.find(Const_section_id(object, shndx));
1210           if (it == this->section_segment_map_.end())
1211             {
1212               os = this->choose_output_section(object, name, sh_type,
1213                                                shdr.get_sh_flags(), true,
1214                                                ORDER_INVALID, false, false,
1215                                                true);
1216             }
1217           else
1218             {
1219               // We know the name of the output section, directly call
1220               // get_output_section here by-passing choose_output_section.
1221               elfcpp::Elf_Xword flags
1222                 = this->get_output_section_flags(shdr.get_sh_flags());
1223
1224               const char* os_name = it->second->name;
1225               Stringpool::Key name_key;
1226               os_name = this->namepool_.add(os_name, true, &name_key);
1227               os = this->get_output_section(os_name, name_key, sh_type, flags,
1228                                         ORDER_INVALID, false);
1229               if (!os->is_unique_segment())
1230                 {
1231                   os->set_is_unique_segment();
1232                   os->set_extra_segment_flags(it->second->flags);
1233                   os->set_segment_alignment(it->second->align);
1234                 }
1235             }
1236           }
1237       if (os == NULL)
1238         return NULL;
1239     }
1240
1241   // By default the GNU linker sorts input sections whose names match
1242   // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*.  The
1243   // sections are sorted by name.  This is used to implement
1244   // constructor priority ordering.  We are compatible.  When we put
1245   // .ctor sections in .init_array and .dtor sections in .fini_array,
1246   // we must also sort plain .ctor and .dtor sections.
1247   if (!this->script_options_->saw_sections_clause()
1248       && !parameters->options().relocatable()
1249       && (is_prefix_of(".ctors.", name)
1250           || is_prefix_of(".dtors.", name)
1251           || is_prefix_of(".init_array.", name)
1252           || is_prefix_of(".fini_array.", name)
1253           || (parameters->options().ctors_in_init_array()
1254               && (strcmp(name, ".ctors") == 0
1255                   || strcmp(name, ".dtors") == 0))))
1256     os->set_must_sort_attached_input_sections();
1257
1258   // By default the GNU linker sorts some special text sections ahead
1259   // of others.  We are compatible.
1260   if (parameters->options().text_reorder()
1261       && !this->script_options_->saw_sections_clause()
1262       && !this->is_section_ordering_specified()
1263       && !parameters->options().relocatable()
1264       && Layout::special_ordering_of_input_section(name) >= 0)
1265     os->set_must_sort_attached_input_sections();
1266
1267   // If this is a .ctors or .ctors.* section being mapped to a
1268   // .init_array section, or a .dtors or .dtors.* section being mapped
1269   // to a .fini_array section, we will need to reverse the words if
1270   // there is more than one.  Record this section for later.  See
1271   // ctors_sections_in_init_array above.
1272   if (!this->script_options_->saw_sections_clause()
1273       && !parameters->options().relocatable()
1274       && shdr.get_sh_size() > size / 8
1275       && (((strcmp(name, ".ctors") == 0
1276             || is_prefix_of(".ctors.", name))
1277            && strcmp(os->name(), ".init_array") == 0)
1278           || ((strcmp(name, ".dtors") == 0
1279                || is_prefix_of(".dtors.", name))
1280               && strcmp(os->name(), ".fini_array") == 0)))
1281     ctors_sections_in_init_array.insert(Section_id(object, shndx));
1282
1283   // FIXME: Handle SHF_LINK_ORDER somewhere.
1284
1285   elfcpp::Elf_Xword orig_flags = os->flags();
1286
1287   *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
1288                                this->script_options_->saw_sections_clause());
1289
1290   // If the flags changed, we may have to change the order.
1291   if ((orig_flags & elfcpp::SHF_ALLOC) != 0)
1292     {
1293       orig_flags &= (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
1294       elfcpp::Elf_Xword new_flags =
1295         os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
1296       if (orig_flags != new_flags)
1297         os->set_order(this->default_section_order(os, false));
1298     }
1299
1300   this->have_added_input_section_ = true;
1301
1302   return os;
1303 }
1304
1305 // Maps section SECN to SEGMENT s.
1306 void
1307 Layout::insert_section_segment_map(Const_section_id secn,
1308                                    Unique_segment_info *s)
1309 {
1310   gold_assert(this->unique_segment_for_sections_specified_);
1311   this->section_segment_map_[secn] = s;
1312 }
1313
1314 // Handle a relocation section when doing a relocatable link.
1315
1316 template<int size, bool big_endian>
1317 Output_section*
1318 Layout::layout_reloc(Sized_relobj_file<size, big_endian>*,
1319                      unsigned int,
1320                      const elfcpp::Shdr<size, big_endian>& shdr,
1321                      Output_section* data_section,
1322                      Relocatable_relocs* rr)
1323 {
1324   gold_assert(parameters->options().relocatable()
1325               || parameters->options().emit_relocs());
1326
1327   int sh_type = shdr.get_sh_type();
1328
1329   std::string name;
1330   if (sh_type == elfcpp::SHT_REL)
1331     name = ".rel";
1332   else if (sh_type == elfcpp::SHT_RELA)
1333     name = ".rela";
1334   else
1335     gold_unreachable();
1336   name += data_section->name();
1337
1338   // If the output data section already has a reloc section, use that;
1339   // otherwise, make a new one.
1340   Output_section* os = data_section->reloc_section();
1341   if (os == NULL)
1342     {
1343       const char* n = this->namepool_.add(name.c_str(), true, NULL);
1344       os = this->make_output_section(n, sh_type, shdr.get_sh_flags(),
1345                                      ORDER_INVALID, false);
1346       os->set_should_link_to_symtab();
1347       os->set_info_section(data_section);
1348       data_section->set_reloc_section(os);
1349     }
1350
1351   Output_section_data* posd;
1352   if (sh_type == elfcpp::SHT_REL)
1353     {
1354       os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
1355       posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
1356                                            size,
1357                                            big_endian>(rr);
1358     }
1359   else if (sh_type == elfcpp::SHT_RELA)
1360     {
1361       os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
1362       posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
1363                                            size,
1364                                            big_endian>(rr);
1365     }
1366   else
1367     gold_unreachable();
1368
1369   os->add_output_section_data(posd);
1370   rr->set_output_data(posd);
1371
1372   return os;
1373 }
1374
1375 // Handle a group section when doing a relocatable link.
1376
1377 template<int size, bool big_endian>
1378 void
1379 Layout::layout_group(Symbol_table* symtab,
1380                      Sized_relobj_file<size, big_endian>* object,
1381                      unsigned int,
1382                      const char* group_section_name,
1383                      const char* signature,
1384                      const elfcpp::Shdr<size, big_endian>& shdr,
1385                      elfcpp::Elf_Word flags,
1386                      std::vector<unsigned int>* shndxes)
1387 {
1388   gold_assert(parameters->options().relocatable());
1389   gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
1390   group_section_name = this->namepool_.add(group_section_name, true, NULL);
1391   Output_section* os = this->make_output_section(group_section_name,
1392                                                  elfcpp::SHT_GROUP,
1393                                                  shdr.get_sh_flags(),
1394                                                  ORDER_INVALID, false);
1395
1396   // We need to find a symbol with the signature in the symbol table.
1397   // If we don't find one now, we need to look again later.
1398   Symbol* sym = symtab->lookup(signature, NULL);
1399   if (sym != NULL)
1400     os->set_info_symndx(sym);
1401   else
1402     {
1403       // Reserve some space to minimize reallocations.
1404       if (this->group_signatures_.empty())
1405         this->group_signatures_.reserve(this->number_of_input_files_ * 16);
1406
1407       // We will wind up using a symbol whose name is the signature.
1408       // So just put the signature in the symbol name pool to save it.
1409       signature = symtab->canonicalize_name(signature);
1410       this->group_signatures_.push_back(Group_signature(os, signature));
1411     }
1412
1413   os->set_should_link_to_symtab();
1414   os->set_entsize(4);
1415
1416   section_size_type entry_count =
1417     convert_to_section_size_type(shdr.get_sh_size() / 4);
1418   Output_section_data* posd =
1419     new Output_data_group<size, big_endian>(object, entry_count, flags,
1420                                             shndxes);
1421   os->add_output_section_data(posd);
1422 }
1423
1424 // Special GNU handling of sections name .eh_frame.  They will
1425 // normally hold exception frame data as defined by the C++ ABI
1426 // (http://codesourcery.com/cxx-abi/).
1427
1428 template<int size, bool big_endian>
1429 Output_section*
1430 Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
1431                         const unsigned char* symbols,
1432                         off_t symbols_size,
1433                         const unsigned char* symbol_names,
1434                         off_t symbol_names_size,
1435                         unsigned int shndx,
1436                         const elfcpp::Shdr<size, big_endian>& shdr,
1437                         unsigned int reloc_shndx, unsigned int reloc_type,
1438                         off_t* off)
1439 {
1440   const unsigned int unwind_section_type =
1441       parameters->target().unwind_section_type();
1442
1443   gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS
1444               || shdr.get_sh_type() == unwind_section_type);
1445   gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
1446
1447   Output_section* os = this->make_eh_frame_section(object);
1448   if (os == NULL)
1449     return NULL;
1450
1451   gold_assert(this->eh_frame_section_ == os);
1452
1453   elfcpp::Elf_Xword orig_flags = os->flags();
1454
1455   Eh_frame::Eh_frame_section_disposition disp =
1456       Eh_frame::EH_UNRECOGNIZED_SECTION;
1457   if (!parameters->incremental())
1458     {
1459       disp = this->eh_frame_data_->add_ehframe_input_section(object,
1460                                                              symbols,
1461                                                              symbols_size,
1462                                                              symbol_names,
1463                                                              symbol_names_size,
1464                                                              shndx,
1465                                                              reloc_shndx,
1466                                                              reloc_type);
1467     }
1468
1469   if (disp == Eh_frame::EH_OPTIMIZABLE_SECTION)
1470     {
1471       os->update_flags_for_input_section(shdr.get_sh_flags());
1472
1473       // A writable .eh_frame section is a RELRO section.
1474       if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1475           != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1476         {
1477           os->set_is_relro();
1478           os->set_order(ORDER_RELRO);
1479         }
1480
1481       *off = -1;
1482       return os;
1483     }
1484
1485   if (disp == Eh_frame::EH_END_MARKER_SECTION && !this->added_eh_frame_data_)
1486     {
1487       // We found the end marker section, so now we can add the set of
1488       // optimized sections to the output section.  We need to postpone
1489       // adding this until we've found a section we can optimize so that
1490       // the .eh_frame section in crtbeginT.o winds up at the start of
1491       // the output section.
1492       os->add_output_section_data(this->eh_frame_data_);
1493       this->added_eh_frame_data_ = true;
1494      }
1495
1496   // We couldn't handle this .eh_frame section for some reason.
1497   // Add it as a normal section.
1498   bool saw_sections_clause = this->script_options_->saw_sections_clause();
1499   *off = os->add_input_section(this, object, shndx, ".eh_frame", shdr,
1500                                reloc_shndx, saw_sections_clause);
1501   this->have_added_input_section_ = true;
1502
1503   if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1504       != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1505     os->set_order(this->default_section_order(os, false));
1506
1507   return os;
1508 }
1509
1510 void
1511 Layout::finalize_eh_frame_section()
1512 {
1513   // If we never found an end marker section, we need to add the
1514   // optimized eh sections to the output section now.
1515   if (!parameters->incremental()
1516       && this->eh_frame_section_ != NULL
1517       && !this->added_eh_frame_data_)
1518     {
1519       this->eh_frame_section_->add_output_section_data(this->eh_frame_data_);
1520       this->added_eh_frame_data_ = true;
1521     }
1522 }
1523
1524 // Create and return the magic .eh_frame section.  Create
1525 // .eh_frame_hdr also if appropriate.  OBJECT is the object with the
1526 // input .eh_frame section; it may be NULL.
1527
1528 Output_section*
1529 Layout::make_eh_frame_section(const Relobj* object)
1530 {
1531   const unsigned int unwind_section_type =
1532       parameters->target().unwind_section_type();
1533
1534   Output_section* os = this->choose_output_section(object, ".eh_frame",
1535                                                    unwind_section_type,
1536                                                    elfcpp::SHF_ALLOC, false,
1537                                                    ORDER_EHFRAME, false, false,
1538                                                    false);
1539   if (os == NULL)
1540     return NULL;
1541
1542   if (this->eh_frame_section_ == NULL)
1543     {
1544       this->eh_frame_section_ = os;
1545       this->eh_frame_data_ = new Eh_frame();
1546
1547       // For incremental linking, we do not optimize .eh_frame sections
1548       // or create a .eh_frame_hdr section.
1549       if (parameters->options().eh_frame_hdr() && !parameters->incremental())
1550         {
1551           Output_section* hdr_os =
1552             this->choose_output_section(NULL, ".eh_frame_hdr",
1553                                         unwind_section_type,
1554                                         elfcpp::SHF_ALLOC, false,
1555                                         ORDER_EHFRAME, false, false,
1556                                         false);
1557
1558           if (hdr_os != NULL)
1559             {
1560               Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
1561                                                         this->eh_frame_data_);
1562               hdr_os->add_output_section_data(hdr_posd);
1563
1564               hdr_os->set_after_input_sections();
1565
1566               if (!this->script_options_->saw_phdrs_clause())
1567                 {
1568                   Output_segment* hdr_oseg;
1569                   hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
1570                                                        elfcpp::PF_R);
1571                   hdr_oseg->add_output_section_to_nonload(hdr_os,
1572                                                           elfcpp::PF_R);
1573                 }
1574
1575               this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
1576             }
1577         }
1578     }
1579
1580   return os;
1581 }
1582
1583 // Add an exception frame for a PLT.  This is called from target code.
1584
1585 void
1586 Layout::add_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data,
1587                              size_t cie_length, const unsigned char* fde_data,
1588                              size_t fde_length)
1589 {
1590   if (parameters->incremental())
1591     {
1592       // FIXME: Maybe this could work some day....
1593       return;
1594     }
1595   Output_section* os = this->make_eh_frame_section(NULL);
1596   if (os == NULL)
1597     return;
1598   this->eh_frame_data_->add_ehframe_for_plt(plt, cie_data, cie_length,
1599                                             fde_data, fde_length);
1600   if (!this->added_eh_frame_data_)
1601     {
1602       os->add_output_section_data(this->eh_frame_data_);
1603       this->added_eh_frame_data_ = true;
1604     }
1605 }
1606
1607 // Remove .eh_frame information for a PLT.  FDEs using the CIE must
1608 // be removed in reverse order to the order they were added.
1609
1610 void
1611 Layout::remove_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data,
1612                                 size_t cie_length, const unsigned char* fde_data,
1613                                 size_t fde_length)
1614 {
1615   if (parameters->incremental())
1616     {
1617       // FIXME: Maybe this could work some day....
1618       return;
1619     }
1620   this->eh_frame_data_->remove_ehframe_for_plt(plt, cie_data, cie_length,
1621                                                fde_data, fde_length);
1622 }
1623
1624 // Scan a .debug_info or .debug_types section, and add summary
1625 // information to the .gdb_index section.
1626
1627 template<int size, bool big_endian>
1628 void
1629 Layout::add_to_gdb_index(bool is_type_unit,
1630                          Sized_relobj<size, big_endian>* object,
1631                          const unsigned char* symbols,
1632                          off_t symbols_size,
1633                          unsigned int shndx,
1634                          unsigned int reloc_shndx,
1635                          unsigned int reloc_type)
1636 {
1637   if (this->gdb_index_data_ == NULL)
1638     {
1639       Output_section* os = this->choose_output_section(NULL, ".gdb_index",
1640                                                        elfcpp::SHT_PROGBITS, 0,
1641                                                        false, ORDER_INVALID,
1642                                                        false, false, false);
1643       if (os == NULL)
1644         return;
1645
1646       this->gdb_index_data_ = new Gdb_index(os);
1647       os->add_output_section_data(this->gdb_index_data_);
1648       os->set_after_input_sections();
1649     }
1650
1651   this->gdb_index_data_->scan_debug_info(is_type_unit, object, symbols,
1652                                          symbols_size, shndx, reloc_shndx,
1653                                          reloc_type);
1654 }
1655
1656 // Add POSD to an output section using NAME, TYPE, and FLAGS.  Return
1657 // the output section.
1658
1659 Output_section*
1660 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
1661                                 elfcpp::Elf_Xword flags,
1662                                 Output_section_data* posd,
1663                                 Output_section_order order, bool is_relro)
1664 {
1665   Output_section* os = this->choose_output_section(NULL, name, type, flags,
1666                                                    false, order, is_relro,
1667                                                    false, false);
1668   if (os != NULL)
1669     os->add_output_section_data(posd);
1670   return os;
1671 }
1672
1673 // Map section flags to segment flags.
1674
1675 elfcpp::Elf_Word
1676 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
1677 {
1678   elfcpp::Elf_Word ret = elfcpp::PF_R;
1679   if ((flags & elfcpp::SHF_WRITE) != 0)
1680     ret |= elfcpp::PF_W;
1681   if ((flags & elfcpp::SHF_EXECINSTR) != 0)
1682     ret |= elfcpp::PF_X;
1683   return ret;
1684 }
1685
1686 // Make a new Output_section, and attach it to segments as
1687 // appropriate.  ORDER is the order in which this section should
1688 // appear in the output segment.  IS_RELRO is true if this is a relro
1689 // (read-only after relocations) section.
1690
1691 Output_section*
1692 Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
1693                             elfcpp::Elf_Xword flags,
1694                             Output_section_order order, bool is_relro)
1695 {
1696   Output_section* os;
1697   if ((flags & elfcpp::SHF_ALLOC) == 0
1698       && strcmp(parameters->options().compress_debug_sections(), "none") != 0
1699       && is_compressible_debug_section(name))
1700     os = new Output_compressed_section(&parameters->options(), name, type,
1701                                        flags);
1702   else if ((flags & elfcpp::SHF_ALLOC) == 0
1703            && parameters->options().strip_debug_non_line()
1704            && strcmp(".debug_abbrev", name) == 0)
1705     {
1706       os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
1707           name, type, flags);
1708       if (this->debug_info_)
1709         this->debug_info_->set_abbreviations(this->debug_abbrev_);
1710     }
1711   else if ((flags & elfcpp::SHF_ALLOC) == 0
1712            && parameters->options().strip_debug_non_line()
1713            && strcmp(".debug_info", name) == 0)
1714     {
1715       os = this->debug_info_ = new Output_reduced_debug_info_section(
1716           name, type, flags);
1717       if (this->debug_abbrev_)
1718         this->debug_info_->set_abbreviations(this->debug_abbrev_);
1719     }
1720   else
1721     {
1722       // Sometimes .init_array*, .preinit_array* and .fini_array* do
1723       // not have correct section types.  Force them here.
1724       if (type == elfcpp::SHT_PROGBITS)
1725         {
1726           if (is_prefix_of(".init_array", name))
1727             type = elfcpp::SHT_INIT_ARRAY;
1728           else if (is_prefix_of(".preinit_array", name))
1729             type = elfcpp::SHT_PREINIT_ARRAY;
1730           else if (is_prefix_of(".fini_array", name))
1731             type = elfcpp::SHT_FINI_ARRAY;
1732         }
1733
1734       // FIXME: const_cast is ugly.
1735       Target* target = const_cast<Target*>(&parameters->target());
1736       os = target->make_output_section(name, type, flags);
1737     }
1738
1739   // With -z relro, we have to recognize the special sections by name.
1740   // There is no other way.
1741   bool is_relro_local = false;
1742   if (!this->script_options_->saw_sections_clause()
1743       && parameters->options().relro()
1744       && (flags & elfcpp::SHF_ALLOC) != 0
1745       && (flags & elfcpp::SHF_WRITE) != 0)
1746     {
1747       if (type == elfcpp::SHT_PROGBITS)
1748         {
1749           if ((flags & elfcpp::SHF_TLS) != 0)
1750             is_relro = true;
1751           else if (strcmp(name, ".data.rel.ro") == 0)
1752             is_relro = true;
1753           else if (strcmp(name, ".data.rel.ro.local") == 0)
1754             {
1755               is_relro = true;
1756               is_relro_local = true;
1757             }
1758           else if (strcmp(name, ".ctors") == 0
1759                    || strcmp(name, ".dtors") == 0
1760                    || strcmp(name, ".jcr") == 0)
1761             is_relro = true;
1762         }
1763       else if (type == elfcpp::SHT_INIT_ARRAY
1764                || type == elfcpp::SHT_FINI_ARRAY
1765                || type == elfcpp::SHT_PREINIT_ARRAY)
1766         is_relro = true;
1767     }
1768
1769   if (is_relro)
1770     os->set_is_relro();
1771
1772   if (order == ORDER_INVALID && (flags & elfcpp::SHF_ALLOC) != 0)
1773     order = this->default_section_order(os, is_relro_local);
1774
1775   os->set_order(order);
1776
1777   parameters->target().new_output_section(os);
1778
1779   this->section_list_.push_back(os);
1780
1781   // The GNU linker by default sorts some sections by priority, so we
1782   // do the same.  We need to know that this might happen before we
1783   // attach any input sections.
1784   if (!this->script_options_->saw_sections_clause()
1785       && !parameters->options().relocatable()
1786       && (strcmp(name, ".init_array") == 0
1787           || strcmp(name, ".fini_array") == 0
1788           || (!parameters->options().ctors_in_init_array()
1789               && (strcmp(name, ".ctors") == 0
1790                   || strcmp(name, ".dtors") == 0))))
1791     os->set_may_sort_attached_input_sections();
1792
1793   // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1794   // sections before other .text sections.  We are compatible.  We
1795   // need to know that this might happen before we attach any input
1796   // sections.
1797   if (parameters->options().text_reorder()
1798       && !this->script_options_->saw_sections_clause()
1799       && !this->is_section_ordering_specified()
1800       && !parameters->options().relocatable()
1801       && strcmp(name, ".text") == 0)
1802     os->set_may_sort_attached_input_sections();
1803
1804   // GNU linker sorts section by name with --sort-section=name.
1805   if (strcmp(parameters->options().sort_section(), "name") == 0)
1806       os->set_must_sort_attached_input_sections();
1807
1808   // Check for .stab*str sections, as .stab* sections need to link to
1809   // them.
1810   if (type == elfcpp::SHT_STRTAB
1811       && !this->have_stabstr_section_
1812       && strncmp(name, ".stab", 5) == 0
1813       && strcmp(name + strlen(name) - 3, "str") == 0)
1814     this->have_stabstr_section_ = true;
1815
1816   // During a full incremental link, we add patch space to most
1817   // PROGBITS and NOBITS sections.  Flag those that may be
1818   // arbitrarily padded.
1819   if ((type == elfcpp::SHT_PROGBITS || type == elfcpp::SHT_NOBITS)
1820       && order != ORDER_INTERP
1821       && order != ORDER_INIT
1822       && order != ORDER_PLT
1823       && order != ORDER_FINI
1824       && order != ORDER_RELRO_LAST
1825       && order != ORDER_NON_RELRO_FIRST
1826       && strcmp(name, ".eh_frame") != 0
1827       && strcmp(name, ".ctors") != 0
1828       && strcmp(name, ".dtors") != 0
1829       && strcmp(name, ".jcr") != 0)
1830     {
1831       os->set_is_patch_space_allowed();
1832
1833       // Certain sections require "holes" to be filled with
1834       // specific fill patterns.  These fill patterns may have
1835       // a minimum size, so we must prevent allocations from the
1836       // free list that leave a hole smaller than the minimum.
1837       if (strcmp(name, ".debug_info") == 0)
1838         os->set_free_space_fill(new Output_fill_debug_info(false));
1839       else if (strcmp(name, ".debug_types") == 0)
1840         os->set_free_space_fill(new Output_fill_debug_info(true));
1841       else if (strcmp(name, ".debug_line") == 0)
1842         os->set_free_space_fill(new Output_fill_debug_line());
1843     }
1844
1845   // If we have already attached the sections to segments, then we
1846   // need to attach this one now.  This happens for sections created
1847   // directly by the linker.
1848   if (this->sections_are_attached_)
1849     this->attach_section_to_segment(&parameters->target(), os);
1850
1851   return os;
1852 }
1853
1854 // Return the default order in which a section should be placed in an
1855 // output segment.  This function captures a lot of the ideas in
1856 // ld/scripttempl/elf.sc in the GNU linker.  Note that the order of a
1857 // linker created section is normally set when the section is created;
1858 // this function is used for input sections.
1859
1860 Output_section_order
1861 Layout::default_section_order(Output_section* os, bool is_relro_local)
1862 {
1863   gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
1864   bool is_write = (os->flags() & elfcpp::SHF_WRITE) != 0;
1865   bool is_execinstr = (os->flags() & elfcpp::SHF_EXECINSTR) != 0;
1866   bool is_bss = false;
1867
1868   switch (os->type())
1869     {
1870     default:
1871     case elfcpp::SHT_PROGBITS:
1872       break;
1873     case elfcpp::SHT_NOBITS:
1874       is_bss = true;
1875       break;
1876     case elfcpp::SHT_RELA:
1877     case elfcpp::SHT_REL:
1878       if (!is_write)
1879         return ORDER_DYNAMIC_RELOCS;
1880       break;
1881     case elfcpp::SHT_HASH:
1882     case elfcpp::SHT_DYNAMIC:
1883     case elfcpp::SHT_SHLIB:
1884     case elfcpp::SHT_DYNSYM:
1885     case elfcpp::SHT_GNU_HASH:
1886     case elfcpp::SHT_GNU_verdef:
1887     case elfcpp::SHT_GNU_verneed:
1888     case elfcpp::SHT_GNU_versym:
1889       if (!is_write)
1890         return ORDER_DYNAMIC_LINKER;
1891       break;
1892     case elfcpp::SHT_NOTE:
1893       return is_write ? ORDER_RW_NOTE : ORDER_RO_NOTE;
1894     }
1895
1896   if ((os->flags() & elfcpp::SHF_TLS) != 0)
1897     return is_bss ? ORDER_TLS_BSS : ORDER_TLS_DATA;
1898
1899   if (!is_bss && !is_write)
1900     {
1901       if (is_execinstr)
1902         {
1903           if (strcmp(os->name(), ".init") == 0)
1904             return ORDER_INIT;
1905           else if (strcmp(os->name(), ".fini") == 0)
1906             return ORDER_FINI;
1907           else if (parameters->options().keep_text_section_prefix())
1908             {
1909               // -z,keep-text-section-prefix introduces additional
1910               // output sections.
1911               if (strcmp(os->name(), ".text.hot") == 0)
1912                 return ORDER_TEXT_HOT;
1913               else if (strcmp(os->name(), ".text.startup") == 0)
1914                 return ORDER_TEXT_STARTUP;
1915               else if (strcmp(os->name(), ".text.exit") == 0)
1916                 return ORDER_TEXT_EXIT;
1917               else if (strcmp(os->name(), ".text.unlikely") == 0)
1918                 return ORDER_TEXT_UNLIKELY;
1919             }
1920         }
1921       return is_execinstr ? ORDER_TEXT : ORDER_READONLY;
1922     }
1923
1924   if (os->is_relro())
1925     return is_relro_local ? ORDER_RELRO_LOCAL : ORDER_RELRO;
1926
1927   if (os->is_small_section())
1928     return is_bss ? ORDER_SMALL_BSS : ORDER_SMALL_DATA;
1929   if (os->is_large_section())
1930     return is_bss ? ORDER_LARGE_BSS : ORDER_LARGE_DATA;
1931
1932   return is_bss ? ORDER_BSS : ORDER_DATA;
1933 }
1934
1935 // Attach output sections to segments.  This is called after we have
1936 // seen all the input sections.
1937
1938 void
1939 Layout::attach_sections_to_segments(const Target* target)
1940 {
1941   for (Section_list::iterator p = this->section_list_.begin();
1942        p != this->section_list_.end();
1943        ++p)
1944     this->attach_section_to_segment(target, *p);
1945
1946   this->sections_are_attached_ = true;
1947 }
1948
1949 // Attach an output section to a segment.
1950
1951 void
1952 Layout::attach_section_to_segment(const Target* target, Output_section* os)
1953 {
1954   if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
1955     this->unattached_section_list_.push_back(os);
1956   else
1957     this->attach_allocated_section_to_segment(target, os);
1958 }
1959
1960 // Attach an allocated output section to a segment.
1961
1962 void
1963 Layout::attach_allocated_section_to_segment(const Target* target,
1964                                             Output_section* os)
1965 {
1966   elfcpp::Elf_Xword flags = os->flags();
1967   gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
1968
1969   if (parameters->options().relocatable())
1970     return;
1971
1972   // If we have a SECTIONS clause, we can't handle the attachment to
1973   // segments until after we've seen all the sections.
1974   if (this->script_options_->saw_sections_clause())
1975     return;
1976
1977   gold_assert(!this->script_options_->saw_phdrs_clause());
1978
1979   // This output section goes into a PT_LOAD segment.
1980
1981   elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
1982
1983   // If this output section's segment has extra flags that need to be set,
1984   // coming from a linker plugin, do that.
1985   seg_flags |= os->extra_segment_flags();
1986
1987   // Check for --section-start.
1988   uint64_t addr;
1989   bool is_address_set = parameters->options().section_start(os->name(), &addr);
1990
1991   // In general the only thing we really care about for PT_LOAD
1992   // segments is whether or not they are writable or executable,
1993   // so that is how we search for them.
1994   // Large data sections also go into their own PT_LOAD segment.
1995   // People who need segments sorted on some other basis will
1996   // have to use a linker script.
1997
1998   Segment_list::const_iterator p;
1999   if (!os->is_unique_segment())
2000     {
2001       for (p = this->segment_list_.begin();
2002            p != this->segment_list_.end();
2003            ++p)
2004         {
2005           if ((*p)->type() != elfcpp::PT_LOAD)
2006             continue;
2007           if ((*p)->is_unique_segment())
2008             continue;
2009           if (!parameters->options().omagic()
2010               && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
2011             continue;
2012           if ((target->isolate_execinstr() || parameters->options().rosegment())
2013               && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
2014             continue;
2015           // If -Tbss was specified, we need to separate the data and BSS
2016           // segments.
2017           if (parameters->options().user_set_Tbss())
2018             {
2019               if ((os->type() == elfcpp::SHT_NOBITS)
2020                   == (*p)->has_any_data_sections())
2021                 continue;
2022             }
2023           if (os->is_large_data_section() && !(*p)->is_large_data_segment())
2024             continue;
2025
2026           if (is_address_set)
2027             {
2028               if ((*p)->are_addresses_set())
2029                 continue;
2030
2031               (*p)->add_initial_output_data(os);
2032               (*p)->update_flags_for_output_section(seg_flags);
2033               (*p)->set_addresses(addr, addr);
2034               break;
2035             }
2036
2037           (*p)->add_output_section_to_load(this, os, seg_flags);
2038           break;
2039         }
2040     }
2041
2042   if (p == this->segment_list_.end()
2043       || os->is_unique_segment())
2044     {
2045       Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
2046                                                        seg_flags);
2047       if (os->is_large_data_section())
2048         oseg->set_is_large_data_segment();
2049       oseg->add_output_section_to_load(this, os, seg_flags);
2050       if (is_address_set)
2051         oseg->set_addresses(addr, addr);
2052       // Check if segment should be marked unique.  For segments marked
2053       // unique by linker plugins, set the new alignment if specified.
2054       if (os->is_unique_segment())
2055         {
2056           oseg->set_is_unique_segment();
2057           if (os->segment_alignment() != 0)
2058             oseg->set_minimum_p_align(os->segment_alignment());
2059         }
2060     }
2061
2062   // If we see a loadable SHT_NOTE section, we create a PT_NOTE
2063   // segment.
2064   if (os->type() == elfcpp::SHT_NOTE)
2065     {
2066       // See if we already have an equivalent PT_NOTE segment.
2067       for (p = this->segment_list_.begin();
2068            p != segment_list_.end();
2069            ++p)
2070         {
2071           if ((*p)->type() == elfcpp::PT_NOTE
2072               && (((*p)->flags() & elfcpp::PF_W)
2073                   == (seg_flags & elfcpp::PF_W)))
2074             {
2075               (*p)->add_output_section_to_nonload(os, seg_flags);
2076               break;
2077             }
2078         }
2079
2080       if (p == this->segment_list_.end())
2081         {
2082           Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
2083                                                            seg_flags);
2084           oseg->add_output_section_to_nonload(os, seg_flags);
2085         }
2086     }
2087
2088   // If we see a loadable SHF_TLS section, we create a PT_TLS
2089   // segment.  There can only be one such segment.
2090   if ((flags & elfcpp::SHF_TLS) != 0)
2091     {
2092       if (this->tls_segment_ == NULL)
2093         this->make_output_segment(elfcpp::PT_TLS, seg_flags);
2094       this->tls_segment_->add_output_section_to_nonload(os, seg_flags);
2095     }
2096
2097   // If -z relro is in effect, and we see a relro section, we create a
2098   // PT_GNU_RELRO segment.  There can only be one such segment.
2099   if (os->is_relro() && parameters->options().relro())
2100     {
2101       gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
2102       if (this->relro_segment_ == NULL)
2103         this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
2104       this->relro_segment_->add_output_section_to_nonload(os, seg_flags);
2105     }
2106
2107   // If we see a section named .interp, put it into a PT_INTERP
2108   // segment.  This seems broken to me, but this is what GNU ld does,
2109   // and glibc expects it.
2110   if (strcmp(os->name(), ".interp") == 0
2111       && !this->script_options_->saw_phdrs_clause())
2112     {
2113       if (this->interp_segment_ == NULL)
2114         this->make_output_segment(elfcpp::PT_INTERP, seg_flags);
2115       else
2116         gold_warning(_("multiple '.interp' sections in input files "
2117                        "may cause confusing PT_INTERP segment"));
2118       this->interp_segment_->add_output_section_to_nonload(os, seg_flags);
2119     }
2120 }
2121
2122 // Make an output section for a script.
2123
2124 Output_section*
2125 Layout::make_output_section_for_script(
2126     const char* name,
2127     Script_sections::Section_type section_type)
2128 {
2129   name = this->namepool_.add(name, false, NULL);
2130   elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC;
2131   if (section_type == Script_sections::ST_NOLOAD)
2132     sh_flags = 0;
2133   Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
2134                                                  sh_flags, ORDER_INVALID,
2135                                                  false);
2136   os->set_found_in_sections_clause();
2137   if (section_type == Script_sections::ST_NOLOAD)
2138     os->set_is_noload();
2139   return os;
2140 }
2141
2142 // Return the number of segments we expect to see.
2143
2144 size_t
2145 Layout::expected_segment_count() const
2146 {
2147   size_t ret = this->segment_list_.size();
2148
2149   // If we didn't see a SECTIONS clause in a linker script, we should
2150   // already have the complete list of segments.  Otherwise we ask the
2151   // SECTIONS clause how many segments it expects, and add in the ones
2152   // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
2153
2154   if (!this->script_options_->saw_sections_clause())
2155     return ret;
2156   else
2157     {
2158       const Script_sections* ss = this->script_options_->script_sections();
2159       return ret + ss->expected_segment_count(this);
2160     }
2161 }
2162
2163 // Handle the .note.GNU-stack section at layout time.  SEEN_GNU_STACK
2164 // is whether we saw a .note.GNU-stack section in the object file.
2165 // GNU_STACK_FLAGS is the section flags.  The flags give the
2166 // protection required for stack memory.  We record this in an
2167 // executable as a PT_GNU_STACK segment.  If an object file does not
2168 // have a .note.GNU-stack segment, we must assume that it is an old
2169 // object.  On some targets that will force an executable stack.
2170
2171 void
2172 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags,
2173                          const Object* obj)
2174 {
2175   if (!seen_gnu_stack)
2176     {
2177       this->input_without_gnu_stack_note_ = true;
2178       if (parameters->options().warn_execstack()
2179           && parameters->target().is_default_stack_executable())
2180         gold_warning(_("%s: missing .note.GNU-stack section"
2181                        " implies executable stack"),
2182                      obj->name().c_str());
2183     }
2184   else
2185     {
2186       this->input_with_gnu_stack_note_ = true;
2187       if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
2188         {
2189           this->input_requires_executable_stack_ = true;
2190           if (parameters->options().warn_execstack())
2191             gold_warning(_("%s: requires executable stack"),
2192                          obj->name().c_str());
2193         }
2194     }
2195 }
2196
2197 // Read a value with given size and endianness.
2198
2199 static inline uint64_t
2200 read_sized_value(size_t size, const unsigned char* buf, bool is_big_endian,
2201                  const Object* object)
2202 {
2203   uint64_t val = 0;
2204   if (size == 4)
2205     {
2206       if (is_big_endian)
2207         val = elfcpp::Swap<32, true>::readval(buf);
2208       else
2209         val = elfcpp::Swap<32, false>::readval(buf);
2210     }
2211   else if (size == 8)
2212     {
2213       if (is_big_endian)
2214         val = elfcpp::Swap<64, true>::readval(buf);
2215       else
2216         val = elfcpp::Swap<64, false>::readval(buf);
2217     }
2218   else
2219     {
2220       gold_warning(_("%s: in .note.gnu.properties section, "
2221                      "pr_datasz must be 4 or 8"),
2222                    object->name().c_str());
2223     }
2224   return val;
2225 }
2226
2227 // Write a value with given size and endianness.
2228
2229 static inline void
2230 write_sized_value(uint64_t value, size_t size, unsigned char* buf,
2231                   bool is_big_endian)
2232 {
2233   if (size == 4)
2234     {
2235       if (is_big_endian)
2236         elfcpp::Swap<32, true>::writeval(buf, static_cast<uint32_t>(value));
2237       else
2238         elfcpp::Swap<32, false>::writeval(buf, static_cast<uint32_t>(value));
2239     }
2240   else if (size == 8)
2241     {
2242       if (is_big_endian)
2243         elfcpp::Swap<64, true>::writeval(buf, value);
2244       else
2245         elfcpp::Swap<64, false>::writeval(buf, value);
2246     }
2247   else
2248     {
2249       // We will have already complained about this.
2250     }
2251 }
2252
2253 // Handle the .note.gnu.property section at layout time.
2254
2255 void
2256 Layout::layout_gnu_property(unsigned int note_type,
2257                             unsigned int pr_type,
2258                             size_t pr_datasz,
2259                             const unsigned char* pr_data,
2260                             const Object* object)
2261 {
2262   // We currently support only the one note type.
2263   gold_assert(note_type == elfcpp::NT_GNU_PROPERTY_TYPE_0);
2264
2265   Gnu_properties::iterator pprop = this->gnu_properties_.find(pr_type);
2266   if (pprop == this->gnu_properties_.end())
2267     {
2268       Gnu_property prop;
2269       prop.pr_datasz = pr_datasz;
2270       prop.pr_data = new unsigned char[pr_datasz];
2271       memcpy(prop.pr_data, pr_data, pr_datasz);
2272       this->gnu_properties_[pr_type] = prop;
2273     }
2274   else
2275     {
2276       if (pr_type >= elfcpp::GNU_PROPERTY_LOPROC
2277           && pr_type < elfcpp::GNU_PROPERTY_HIPROC)
2278         {
2279           // Target-dependent property value; call the target to merge.
2280           parameters->target().merge_gnu_property(note_type,
2281                                                   pr_type,
2282                                                   pr_datasz,
2283                                                   pr_data,
2284                                                   pprop->second.pr_datasz,
2285                                                   pprop->second.pr_data,
2286                                                   object);
2287         }
2288       else
2289         {
2290           const bool is_big_endian = parameters->target().is_big_endian();
2291           switch (pr_type)
2292             {
2293             case elfcpp::GNU_PROPERTY_STACK_SIZE:
2294               // Record the maximum value seen.
2295               {
2296                 uint64_t val1 = read_sized_value(pprop->second.pr_datasz,
2297                                                  pprop->second.pr_data,
2298                                                  is_big_endian, object);
2299                 uint64_t val2 = read_sized_value(pr_datasz, pr_data,
2300                                                  is_big_endian, object);
2301                 if (val2 > val1)
2302                   write_sized_value(val2, pprop->second.pr_datasz,
2303                                     pprop->second.pr_data, is_big_endian);
2304               }
2305               break;
2306             case elfcpp::GNU_PROPERTY_NO_COPY_ON_PROTECTED:
2307               // No data to merge.
2308               break;
2309             default:
2310               gold_warning(_("%s: unknown program property type %d "
2311                              "in .note.gnu.properties section"),
2312                            object->name().c_str(), pr_type);
2313             }
2314         }
2315     }
2316 }
2317
2318 // Create automatic note sections.
2319
2320 void
2321 Layout::create_notes()
2322 {
2323   this->create_gnu_properties_note();
2324   this->create_gold_note();
2325   this->create_stack_segment();
2326   this->create_build_id();
2327 }
2328
2329 // Create the dynamic sections which are needed before we read the
2330 // relocs.
2331
2332 void
2333 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
2334 {
2335   if (parameters->doing_static_link())
2336     return;
2337
2338   this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
2339                                                        elfcpp::SHT_DYNAMIC,
2340                                                        (elfcpp::SHF_ALLOC
2341                                                         | elfcpp::SHF_WRITE),
2342                                                        false, ORDER_RELRO,
2343                                                        true, false, false);
2344
2345   // A linker script may discard .dynamic, so check for NULL.
2346   if (this->dynamic_section_ != NULL)
2347     {
2348       this->dynamic_symbol_ =
2349         symtab->define_in_output_data("_DYNAMIC", NULL,
2350                                       Symbol_table::PREDEFINED,
2351                                       this->dynamic_section_, 0, 0,
2352                                       elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
2353                                       elfcpp::STV_HIDDEN, 0, false, false);
2354
2355       this->dynamic_data_ =  new Output_data_dynamic(&this->dynpool_);
2356
2357       this->dynamic_section_->add_output_section_data(this->dynamic_data_);
2358     }
2359 }
2360
2361 // For each output section whose name can be represented as C symbol,
2362 // define __start and __stop symbols for the section.  This is a GNU
2363 // extension.
2364
2365 void
2366 Layout::define_section_symbols(Symbol_table* symtab)
2367 {
2368   for (Section_list::const_iterator p = this->section_list_.begin();
2369        p != this->section_list_.end();
2370        ++p)
2371     {
2372       const char* const name = (*p)->name();
2373       if (is_cident(name))
2374         {
2375           const std::string name_string(name);
2376           const std::string start_name(cident_section_start_prefix
2377                                        + name_string);
2378           const std::string stop_name(cident_section_stop_prefix
2379                                       + name_string);
2380
2381           symtab->define_in_output_data(start_name.c_str(),
2382                                         NULL, // version
2383                                         Symbol_table::PREDEFINED,
2384                                         *p,
2385                                         0, // value
2386                                         0, // symsize
2387                                         elfcpp::STT_NOTYPE,
2388                                         elfcpp::STB_GLOBAL,
2389                                         elfcpp::STV_PROTECTED,
2390                                         0, // nonvis
2391                                         false, // offset_is_from_end
2392                                         true); // only_if_ref
2393
2394           symtab->define_in_output_data(stop_name.c_str(),
2395                                         NULL, // version
2396                                         Symbol_table::PREDEFINED,
2397                                         *p,
2398                                         0, // value
2399                                         0, // symsize
2400                                         elfcpp::STT_NOTYPE,
2401                                         elfcpp::STB_GLOBAL,
2402                                         elfcpp::STV_PROTECTED,
2403                                         0, // nonvis
2404                                         true, // offset_is_from_end
2405                                         true); // only_if_ref
2406         }
2407     }
2408 }
2409
2410 // Define symbols for group signatures.
2411
2412 void
2413 Layout::define_group_signatures(Symbol_table* symtab)
2414 {
2415   for (Group_signatures::iterator p = this->group_signatures_.begin();
2416        p != this->group_signatures_.end();
2417        ++p)
2418     {
2419       Symbol* sym = symtab->lookup(p->signature, NULL);
2420       if (sym != NULL)
2421         p->section->set_info_symndx(sym);
2422       else
2423         {
2424           // Force the name of the group section to the group
2425           // signature, and use the group's section symbol as the
2426           // signature symbol.
2427           if (strcmp(p->section->name(), p->signature) != 0)
2428             {
2429               const char* name = this->namepool_.add(p->signature,
2430                                                      true, NULL);
2431               p->section->set_name(name);
2432             }
2433           p->section->set_needs_symtab_index();
2434           p->section->set_info_section_symndx(p->section);
2435         }
2436     }
2437
2438   this->group_signatures_.clear();
2439 }
2440
2441 // Find the first read-only PT_LOAD segment, creating one if
2442 // necessary.
2443
2444 Output_segment*
2445 Layout::find_first_load_seg(const Target* target)
2446 {
2447   Output_segment* best = NULL;
2448   for (Segment_list::const_iterator p = this->segment_list_.begin();
2449        p != this->segment_list_.end();
2450        ++p)
2451     {
2452       if ((*p)->type() == elfcpp::PT_LOAD
2453           && ((*p)->flags() & elfcpp::PF_R) != 0
2454           && (parameters->options().omagic()
2455               || ((*p)->flags() & elfcpp::PF_W) == 0)
2456           && (!target->isolate_execinstr()
2457               || ((*p)->flags() & elfcpp::PF_X) == 0))
2458         {
2459           if (best == NULL || this->segment_precedes(*p, best))
2460             best = *p;
2461         }
2462     }
2463   if (best != NULL)
2464     return best;
2465
2466   gold_assert(!this->script_options_->saw_phdrs_clause());
2467
2468   Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
2469                                                        elfcpp::PF_R);
2470   return load_seg;
2471 }
2472
2473 // Save states of all current output segments.  Store saved states
2474 // in SEGMENT_STATES.
2475
2476 void
2477 Layout::save_segments(Segment_states* segment_states)
2478 {
2479   for (Segment_list::const_iterator p = this->segment_list_.begin();
2480        p != this->segment_list_.end();
2481        ++p)
2482     {
2483       Output_segment* segment = *p;
2484       // Shallow copy.
2485       Output_segment* copy = new Output_segment(*segment);
2486       (*segment_states)[segment] = copy;
2487     }
2488 }
2489
2490 // Restore states of output segments and delete any segment not found in
2491 // SEGMENT_STATES.
2492
2493 void
2494 Layout::restore_segments(const Segment_states* segment_states)
2495 {
2496   // Go through the segment list and remove any segment added in the
2497   // relaxation loop.
2498   this->tls_segment_ = NULL;
2499   this->relro_segment_ = NULL;
2500   Segment_list::iterator list_iter = this->segment_list_.begin();
2501   while (list_iter != this->segment_list_.end())
2502     {
2503       Output_segment* segment = *list_iter;
2504       Segment_states::const_iterator states_iter =
2505           segment_states->find(segment);
2506       if (states_iter != segment_states->end())
2507         {
2508           const Output_segment* copy = states_iter->second;
2509           // Shallow copy to restore states.
2510           *segment = *copy;
2511
2512           // Also fix up TLS and RELRO segment pointers as appropriate.
2513           if (segment->type() == elfcpp::PT_TLS)
2514             this->tls_segment_ = segment;
2515           else if (segment->type() == elfcpp::PT_GNU_RELRO)
2516             this->relro_segment_ = segment;
2517
2518           ++list_iter;
2519         }
2520       else
2521         {
2522           list_iter = this->segment_list_.erase(list_iter);
2523           // This is a segment created during section layout.  It should be
2524           // safe to remove it since we should have removed all pointers to it.
2525           delete segment;
2526         }
2527     }
2528 }
2529
2530 // Clean up after relaxation so that sections can be laid out again.
2531
2532 void
2533 Layout::clean_up_after_relaxation()
2534 {
2535   // Restore the segments to point state just prior to the relaxation loop.
2536   Script_sections* script_section = this->script_options_->script_sections();
2537   script_section->release_segments();
2538   this->restore_segments(this->segment_states_);
2539
2540   // Reset section addresses and file offsets
2541   for (Section_list::iterator p = this->section_list_.begin();
2542        p != this->section_list_.end();
2543        ++p)
2544     {
2545       (*p)->restore_states();
2546
2547       // If an input section changes size because of relaxation,
2548       // we need to adjust the section offsets of all input sections.
2549       // after such a section.
2550       if ((*p)->section_offsets_need_adjustment())
2551         (*p)->adjust_section_offsets();
2552
2553       (*p)->reset_address_and_file_offset();
2554     }
2555
2556   // Reset special output object address and file offsets.
2557   for (Data_list::iterator p = this->special_output_list_.begin();
2558        p != this->special_output_list_.end();
2559        ++p)
2560     (*p)->reset_address_and_file_offset();
2561
2562   // A linker script may have created some output section data objects.
2563   // They are useless now.
2564   for (Output_section_data_list::const_iterator p =
2565          this->script_output_section_data_list_.begin();
2566        p != this->script_output_section_data_list_.end();
2567        ++p)
2568     delete *p;
2569   this->script_output_section_data_list_.clear();
2570
2571   // Special-case fill output objects are recreated each time through
2572   // the relaxation loop.
2573   this->reset_relax_output();
2574 }
2575
2576 void
2577 Layout::reset_relax_output()
2578 {
2579   for (Data_list::const_iterator p = this->relax_output_list_.begin();
2580        p != this->relax_output_list_.end();
2581        ++p)
2582     delete *p;
2583   this->relax_output_list_.clear();
2584 }
2585
2586 // Prepare for relaxation.
2587
2588 void
2589 Layout::prepare_for_relaxation()
2590 {
2591   // Create an relaxation debug check if in debugging mode.
2592   if (is_debugging_enabled(DEBUG_RELAXATION))
2593     this->relaxation_debug_check_ = new Relaxation_debug_check();
2594
2595   // Save segment states.
2596   this->segment_states_ = new Segment_states();
2597   this->save_segments(this->segment_states_);
2598
2599   for(Section_list::const_iterator p = this->section_list_.begin();
2600       p != this->section_list_.end();
2601       ++p)
2602     (*p)->save_states();
2603
2604   if (is_debugging_enabled(DEBUG_RELAXATION))
2605     this->relaxation_debug_check_->check_output_data_for_reset_values(
2606         this->section_list_, this->special_output_list_,
2607         this->relax_output_list_);
2608
2609   // Also enable recording of output section data from scripts.
2610   this->record_output_section_data_from_script_ = true;
2611 }
2612
2613 // If the user set the address of the text segment, that may not be
2614 // compatible with putting the segment headers and file headers into
2615 // that segment.  For isolate_execinstr() targets, it's the rodata
2616 // segment rather than text where we might put the headers.
2617 static inline bool
2618 load_seg_unusable_for_headers(const Target* target)
2619 {
2620   const General_options& options = parameters->options();
2621   if (target->isolate_execinstr())
2622     return (options.user_set_Trodata_segment()
2623             && options.Trodata_segment() % target->abi_pagesize() != 0);
2624   else
2625     return (options.user_set_Ttext()
2626             && options.Ttext() % target->abi_pagesize() != 0);
2627 }
2628
2629 // Relaxation loop body:  If target has no relaxation, this runs only once
2630 // Otherwise, the target relaxation hook is called at the end of
2631 // each iteration.  If the hook returns true, it means re-layout of
2632 // section is required.
2633 //
2634 // The number of segments created by a linking script without a PHDRS
2635 // clause may be affected by section sizes and alignments.  There is
2636 // a remote chance that relaxation causes different number of PT_LOAD
2637 // segments are created and sections are attached to different segments.
2638 // Therefore, we always throw away all segments created during section
2639 // layout.  In order to be able to restart the section layout, we keep
2640 // a copy of the segment list right before the relaxation loop and use
2641 // that to restore the segments.
2642 //
2643 // PASS is the current relaxation pass number.
2644 // SYMTAB is a symbol table.
2645 // PLOAD_SEG is the address of a pointer for the load segment.
2646 // PHDR_SEG is a pointer to the PHDR segment.
2647 // SEGMENT_HEADERS points to the output segment header.
2648 // FILE_HEADER points to the output file header.
2649 // PSHNDX is the address to store the output section index.
2650
2651 off_t inline
2652 Layout::relaxation_loop_body(
2653     int pass,
2654     Target* target,
2655     Symbol_table* symtab,
2656     Output_segment** pload_seg,
2657     Output_segment* phdr_seg,
2658     Output_segment_headers* segment_headers,
2659     Output_file_header* file_header,
2660     unsigned int* pshndx)
2661 {
2662   // If this is not the first iteration, we need to clean up after
2663   // relaxation so that we can lay out the sections again.
2664   if (pass != 0)
2665     this->clean_up_after_relaxation();
2666
2667   // If there is a SECTIONS clause, put all the input sections into
2668   // the required order.
2669   Output_segment* load_seg;
2670   if (this->script_options_->saw_sections_clause())
2671     load_seg = this->set_section_addresses_from_script(symtab);
2672   else if (parameters->options().relocatable())
2673     load_seg = NULL;
2674   else
2675     load_seg = this->find_first_load_seg(target);
2676
2677   if (parameters->options().oformat_enum()
2678       != General_options::OBJECT_FORMAT_ELF)
2679     load_seg = NULL;
2680
2681   if (load_seg_unusable_for_headers(target))
2682     {
2683       load_seg = NULL;
2684       phdr_seg = NULL;
2685     }
2686
2687   gold_assert(phdr_seg == NULL
2688               || load_seg != NULL
2689               || this->script_options_->saw_sections_clause());
2690
2691   // If the address of the load segment we found has been set by
2692   // --section-start rather than by a script, then adjust the VMA and
2693   // LMA downward if possible to include the file and section headers.
2694   uint64_t header_gap = 0;
2695   if (load_seg != NULL
2696       && load_seg->are_addresses_set()
2697       && !this->script_options_->saw_sections_clause()
2698       && !parameters->options().relocatable())
2699     {
2700       file_header->finalize_data_size();
2701       segment_headers->finalize_data_size();
2702       size_t sizeof_headers = (file_header->data_size()
2703                                + segment_headers->data_size());
2704       const uint64_t abi_pagesize = target->abi_pagesize();
2705       uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers;
2706       hdr_paddr &= ~(abi_pagesize - 1);
2707       uint64_t subtract = load_seg->paddr() - hdr_paddr;
2708       if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract)
2709         load_seg = NULL;
2710       else
2711         {
2712           load_seg->set_addresses(load_seg->vaddr() - subtract,
2713                                   load_seg->paddr() - subtract);
2714           header_gap = subtract - sizeof_headers;
2715         }
2716     }
2717
2718   // Lay out the segment headers.
2719   if (!parameters->options().relocatable())
2720     {
2721       gold_assert(segment_headers != NULL);
2722       if (header_gap != 0 && load_seg != NULL)
2723         {
2724           Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1);
2725           load_seg->add_initial_output_data(z);
2726         }
2727       if (load_seg != NULL)
2728         load_seg->add_initial_output_data(segment_headers);
2729       if (phdr_seg != NULL)
2730         phdr_seg->add_initial_output_data(segment_headers);
2731     }
2732
2733   // Lay out the file header.
2734   if (load_seg != NULL)
2735     load_seg->add_initial_output_data(file_header);
2736
2737   if (this->script_options_->saw_phdrs_clause()
2738       && !parameters->options().relocatable())
2739     {
2740       // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2741       // clause in a linker script.
2742       Script_sections* ss = this->script_options_->script_sections();
2743       ss->put_headers_in_phdrs(file_header, segment_headers);
2744     }
2745
2746   // We set the output section indexes in set_segment_offsets and
2747   // set_section_indexes.
2748   *pshndx = 1;
2749
2750   // Set the file offsets of all the segments, and all the sections
2751   // they contain.
2752   off_t off;
2753   if (!parameters->options().relocatable())
2754     off = this->set_segment_offsets(target, load_seg, pshndx);
2755   else
2756     off = this->set_relocatable_section_offsets(file_header, pshndx);
2757
2758    // Verify that the dummy relaxation does not change anything.
2759   if (is_debugging_enabled(DEBUG_RELAXATION))
2760     {
2761       if (pass == 0)
2762         this->relaxation_debug_check_->read_sections(this->section_list_);
2763       else
2764         this->relaxation_debug_check_->verify_sections(this->section_list_);
2765     }
2766
2767   *pload_seg = load_seg;
2768   return off;
2769 }
2770
2771 // Search the list of patterns and find the position of the given section
2772 // name in the output section.  If the section name matches a glob
2773 // pattern and a non-glob name, then the non-glob position takes
2774 // precedence.  Return 0 if no match is found.
2775
2776 unsigned int
2777 Layout::find_section_order_index(const std::string& section_name)
2778 {
2779   Unordered_map<std::string, unsigned int>::iterator map_it;
2780   map_it = this->input_section_position_.find(section_name);
2781   if (map_it != this->input_section_position_.end())
2782     return map_it->second;
2783
2784   // Absolute match failed.  Linear search the glob patterns.
2785   std::vector<std::string>::iterator it;
2786   for (it = this->input_section_glob_.begin();
2787        it != this->input_section_glob_.end();
2788        ++it)
2789     {
2790        if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0)
2791          {
2792            map_it = this->input_section_position_.find(*it);
2793            gold_assert(map_it != this->input_section_position_.end());
2794            return map_it->second;
2795          }
2796     }
2797   return 0;
2798 }
2799
2800 // Read the sequence of input sections from the file specified with
2801 // option --section-ordering-file.
2802
2803 void
2804 Layout::read_layout_from_file()
2805 {
2806   const char* filename = parameters->options().section_ordering_file();
2807   std::ifstream in;
2808   std::string line;
2809
2810   in.open(filename);
2811   if (!in)
2812     gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2813                filename, strerror(errno));
2814
2815   std::getline(in, line);   // this chops off the trailing \n, if any
2816   unsigned int position = 1;
2817   this->set_section_ordering_specified();
2818
2819   while (in)
2820     {
2821       if (!line.empty() && line[line.length() - 1] == '\r')   // Windows
2822         line.resize(line.length() - 1);
2823       // Ignore comments, beginning with '#'
2824       if (line[0] == '#')
2825         {
2826           std::getline(in, line);
2827           continue;
2828         }
2829       this->input_section_position_[line] = position;
2830       // Store all glob patterns in a vector.
2831       if (is_wildcard_string(line.c_str()))
2832         this->input_section_glob_.push_back(line);
2833       position++;
2834       std::getline(in, line);
2835     }
2836 }
2837
2838 // Finalize the layout.  When this is called, we have created all the
2839 // output sections and all the output segments which are based on
2840 // input sections.  We have several things to do, and we have to do
2841 // them in the right order, so that we get the right results correctly
2842 // and efficiently.
2843
2844 // 1) Finalize the list of output segments and create the segment
2845 // table header.
2846
2847 // 2) Finalize the dynamic symbol table and associated sections.
2848
2849 // 3) Determine the final file offset of all the output segments.
2850
2851 // 4) Determine the final file offset of all the SHF_ALLOC output
2852 // sections.
2853
2854 // 5) Create the symbol table sections and the section name table
2855 // section.
2856
2857 // 6) Finalize the symbol table: set symbol values to their final
2858 // value and make a final determination of which symbols are going
2859 // into the output symbol table.
2860
2861 // 7) Create the section table header.
2862
2863 // 8) Determine the final file offset of all the output sections which
2864 // are not SHF_ALLOC, including the section table header.
2865
2866 // 9) Finalize the ELF file header.
2867
2868 // This function returns the size of the output file.
2869
2870 off_t
2871 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
2872                  Target* target, const Task* task)
2873 {
2874   unsigned int local_dynamic_count = 0;
2875   unsigned int forced_local_dynamic_count = 0;
2876
2877   target->finalize_sections(this, input_objects, symtab);
2878
2879   this->count_local_symbols(task, input_objects);
2880
2881   this->link_stabs_sections();
2882
2883   Output_segment* phdr_seg = NULL;
2884   if (!parameters->options().relocatable() && !parameters->doing_static_link())
2885     {
2886       // There was a dynamic object in the link.  We need to create
2887       // some information for the dynamic linker.
2888
2889       // Create the PT_PHDR segment which will hold the program
2890       // headers.
2891       if (!this->script_options_->saw_phdrs_clause())
2892         phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
2893
2894       // Create the dynamic symbol table, including the hash table.
2895       Output_section* dynstr;
2896       std::vector<Symbol*> dynamic_symbols;
2897       Versions versions(*this->script_options()->version_script_info(),
2898                         &this->dynpool_);
2899       this->create_dynamic_symtab(input_objects, symtab, &dynstr,
2900                                   &local_dynamic_count,
2901                                   &forced_local_dynamic_count,
2902                                   &dynamic_symbols,
2903                                   &versions);
2904
2905       // Create the .interp section to hold the name of the
2906       // interpreter, and put it in a PT_INTERP segment.  Don't do it
2907       // if we saw a .interp section in an input file.
2908       if ((!parameters->options().shared()
2909            || parameters->options().dynamic_linker() != NULL)
2910           && this->interp_segment_ == NULL)
2911         this->create_interp(target);
2912
2913       // Finish the .dynamic section to hold the dynamic data, and put
2914       // it in a PT_DYNAMIC segment.
2915       this->finish_dynamic_section(input_objects, symtab);
2916
2917       // We should have added everything we need to the dynamic string
2918       // table.
2919       this->dynpool_.set_string_offsets();
2920
2921       // Create the version sections.  We can't do this until the
2922       // dynamic string table is complete.
2923       this->create_version_sections(&versions, symtab,
2924                                     (local_dynamic_count
2925                                      + forced_local_dynamic_count),
2926                                     dynamic_symbols, dynstr);
2927
2928       // Set the size of the _DYNAMIC symbol.  We can't do this until
2929       // after we call create_version_sections.
2930       this->set_dynamic_symbol_size(symtab);
2931     }
2932
2933   // Create segment headers.
2934   Output_segment_headers* segment_headers =
2935     (parameters->options().relocatable()
2936      ? NULL
2937      : new Output_segment_headers(this->segment_list_));
2938
2939   // Lay out the file header.
2940   Output_file_header* file_header = new Output_file_header(target, symtab,
2941                                                            segment_headers);
2942
2943   this->special_output_list_.push_back(file_header);
2944   if (segment_headers != NULL)
2945     this->special_output_list_.push_back(segment_headers);
2946
2947   // Find approriate places for orphan output sections if we are using
2948   // a linker script.
2949   if (this->script_options_->saw_sections_clause())
2950     this->place_orphan_sections_in_script();
2951
2952   Output_segment* load_seg;
2953   off_t off;
2954   unsigned int shndx;
2955   int pass = 0;
2956
2957   // Take a snapshot of the section layout as needed.
2958   if (target->may_relax())
2959     this->prepare_for_relaxation();
2960
2961   // Run the relaxation loop to lay out sections.
2962   do
2963     {
2964       off = this->relaxation_loop_body(pass, target, symtab, &load_seg,
2965                                        phdr_seg, segment_headers, file_header,
2966                                        &shndx);
2967       pass++;
2968     }
2969   while (target->may_relax()
2970          && target->relax(pass, input_objects, symtab, this, task));
2971
2972   // If there is a load segment that contains the file and program headers,
2973   // provide a symbol __ehdr_start pointing there.
2974   // A program can use this to examine itself robustly.
2975   Symbol *ehdr_start = symtab->lookup("__ehdr_start");
2976   if (ehdr_start != NULL && ehdr_start->is_predefined())
2977     {
2978       if (load_seg != NULL)
2979         ehdr_start->set_output_segment(load_seg, Symbol::SEGMENT_START);
2980       else
2981         ehdr_start->set_undefined();
2982     }
2983
2984   // Set the file offsets of all the non-data sections we've seen so
2985   // far which don't have to wait for the input sections.  We need
2986   // this in order to finalize local symbols in non-allocated
2987   // sections.
2988   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2989
2990   // Set the section indexes of all unallocated sections seen so far,
2991   // in case any of them are somehow referenced by a symbol.
2992   shndx = this->set_section_indexes(shndx);
2993
2994   // Create the symbol table sections.
2995   this->create_symtab_sections(input_objects, symtab, shndx, &off,
2996                                local_dynamic_count);
2997   if (!parameters->doing_static_link())
2998     this->assign_local_dynsym_offsets(input_objects);
2999
3000   // Process any symbol assignments from a linker script.  This must
3001   // be called after the symbol table has been finalized.
3002   this->script_options_->finalize_symbols(symtab, this);
3003
3004   // Create the incremental inputs sections.
3005   if (this->incremental_inputs_)
3006     {
3007       this->incremental_inputs_->finalize();
3008       this->create_incremental_info_sections(symtab);
3009     }
3010
3011   // Create the .shstrtab section.
3012   Output_section* shstrtab_section = this->create_shstrtab();
3013
3014   // Set the file offsets of the rest of the non-data sections which
3015   // don't have to wait for the input sections.
3016   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
3017
3018   // Now that all sections have been created, set the section indexes
3019   // for any sections which haven't been done yet.
3020   shndx = this->set_section_indexes(shndx);
3021
3022   // Create the section table header.
3023   this->create_shdrs(shstrtab_section, &off);
3024
3025   // If there are no sections which require postprocessing, we can
3026   // handle the section names now, and avoid a resize later.
3027   if (!this->any_postprocessing_sections_)
3028     {
3029       off = this->set_section_offsets(off,
3030                                       POSTPROCESSING_SECTIONS_PASS);
3031       off =
3032           this->set_section_offsets(off,
3033                                     STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
3034     }
3035
3036   file_header->set_section_info(this->section_headers_, shstrtab_section);
3037
3038   // Now we know exactly where everything goes in the output file
3039   // (except for non-allocated sections which require postprocessing).
3040   Output_data::layout_complete();
3041
3042   this->output_file_size_ = off;
3043
3044   return off;
3045 }
3046
3047 // Create a note header following the format defined in the ELF ABI.
3048 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
3049 // of the section to create, DESCSZ is the size of the descriptor.
3050 // ALLOCATE is true if the section should be allocated in memory.
3051 // This returns the new note section.  It sets *TRAILING_PADDING to
3052 // the number of trailing zero bytes required.
3053
3054 Output_section*
3055 Layout::create_note(const char* name, int note_type,
3056                     const char* section_name, size_t descsz,
3057                     bool allocate, size_t* trailing_padding)
3058 {
3059   // Authorities all agree that the values in a .note field should
3060   // be aligned on 4-byte boundaries for 32-bit binaries.  However,
3061   // they differ on what the alignment is for 64-bit binaries.
3062   // The GABI says unambiguously they take 8-byte alignment:
3063   //    http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
3064   // Other documentation says alignment should always be 4 bytes:
3065   //    http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
3066   // GNU ld and GNU readelf both support the latter (at least as of
3067   // version 2.16.91), and glibc always generates the latter for
3068   // .note.ABI-tag (as of version 1.6), so that's the one we go with
3069   // here.
3070 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION   // This is not defined by default.
3071   const int size = parameters->target().get_size();
3072 #else
3073   const int size = 32;
3074 #endif
3075
3076   // The contents of the .note section.
3077   size_t namesz = strlen(name) + 1;
3078   size_t aligned_namesz = align_address(namesz, size / 8);
3079   size_t aligned_descsz = align_address(descsz, size / 8);
3080
3081   size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
3082
3083   unsigned char* buffer = new unsigned char[notehdrsz];
3084   memset(buffer, 0, notehdrsz);
3085
3086   bool is_big_endian = parameters->target().is_big_endian();
3087
3088   if (size == 32)
3089     {
3090       if (!is_big_endian)
3091         {
3092           elfcpp::Swap<32, false>::writeval(buffer, namesz);
3093           elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
3094           elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
3095         }
3096       else
3097         {
3098           elfcpp::Swap<32, true>::writeval(buffer, namesz);
3099           elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
3100           elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
3101         }
3102     }
3103   else if (size == 64)
3104     {
3105       if (!is_big_endian)
3106         {
3107           elfcpp::Swap<64, false>::writeval(buffer, namesz);
3108           elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
3109           elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
3110         }
3111       else
3112         {
3113           elfcpp::Swap<64, true>::writeval(buffer, namesz);
3114           elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
3115           elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
3116         }
3117     }
3118   else
3119     gold_unreachable();
3120
3121   memcpy(buffer + 3 * (size / 8), name, namesz);
3122
3123   elfcpp::Elf_Xword flags = 0;
3124   Output_section_order order = ORDER_INVALID;
3125   if (allocate)
3126     {
3127       flags = elfcpp::SHF_ALLOC;
3128       order = ORDER_RO_NOTE;
3129     }
3130   Output_section* os = this->choose_output_section(NULL, section_name,
3131                                                    elfcpp::SHT_NOTE,
3132                                                    flags, false, order, false,
3133                                                    false, true);
3134   if (os == NULL)
3135     return NULL;
3136
3137   Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
3138                                                            size / 8,
3139                                                            "** note header");
3140   os->add_output_section_data(posd);
3141
3142   *trailing_padding = aligned_descsz - descsz;
3143
3144   return os;
3145 }
3146
3147 // Create a .note.gnu.properties section to record program properties
3148 // accumulated from the input files.
3149
3150 void
3151 Layout::create_gnu_properties_note()
3152 {
3153   if (this->gnu_properties_.empty())
3154     return;
3155
3156   const unsigned int size = parameters->target().get_size();
3157   const bool is_big_endian = parameters->target().is_big_endian();
3158
3159   // Compute the total size of the properties array.
3160   size_t descsz = 0;
3161   for (Gnu_properties::const_iterator prop = this->gnu_properties_.begin();
3162        prop != this->gnu_properties_.end();
3163        ++prop)
3164     {
3165       descsz = align_address(descsz + 8 + prop->second.pr_datasz, size / 8);
3166     }
3167
3168   // Create the note section.
3169   size_t trailing_padding;
3170   Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_PROPERTY_TYPE_0,
3171                                          ".note.gnu.properties", descsz,
3172                                          true, &trailing_padding);
3173   if (os == NULL)
3174     return;
3175   gold_assert(trailing_padding == 0);
3176
3177   // Allocate and fill the properties array.
3178   unsigned char* desc = new unsigned char[descsz];
3179   unsigned char* p = desc;
3180   for (Gnu_properties::const_iterator prop = this->gnu_properties_.begin();
3181        prop != this->gnu_properties_.end();
3182        ++prop)
3183     {
3184       size_t datasz = prop->second.pr_datasz;
3185       size_t aligned_datasz = align_address(prop->second.pr_datasz, size / 8);
3186       write_sized_value(prop->first, 4, p, is_big_endian);
3187       write_sized_value(datasz, 4, p + 4, is_big_endian);
3188       memcpy(p + 8, prop->second.pr_data, datasz);
3189       if (aligned_datasz > datasz)
3190         memset(p + 8 + datasz, 0, aligned_datasz - datasz);
3191       p += 8 + aligned_datasz;
3192     }
3193   Output_section_data* posd = new Output_data_const(desc, descsz, 4);
3194   os->add_output_section_data(posd);
3195 }
3196
3197 // For an executable or shared library, create a note to record the
3198 // version of gold used to create the binary.
3199
3200 void
3201 Layout::create_gold_note()
3202 {
3203   if (parameters->options().relocatable()
3204       || parameters->incremental_update())
3205     return;
3206
3207   std::string desc = std::string("gold ") + gold::get_version_string();
3208
3209   size_t trailing_padding;
3210   Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
3211                                          ".note.gnu.gold-version", desc.size(),
3212                                          false, &trailing_padding);
3213   if (os == NULL)
3214     return;
3215
3216   Output_section_data* posd = new Output_data_const(desc, 4);
3217   os->add_output_section_data(posd);
3218
3219   if (trailing_padding > 0)
3220     {
3221       posd = new Output_data_zero_fill(trailing_padding, 0);
3222       os->add_output_section_data(posd);
3223     }
3224 }
3225
3226 // Record whether the stack should be executable.  This can be set
3227 // from the command line using the -z execstack or -z noexecstack
3228 // options.  Otherwise, if any input file has a .note.GNU-stack
3229 // section with the SHF_EXECINSTR flag set, the stack should be
3230 // executable.  Otherwise, if at least one input file a
3231 // .note.GNU-stack section, and some input file has no .note.GNU-stack
3232 // section, we use the target default for whether the stack should be
3233 // executable.  If -z stack-size was used to set a p_memsz value for
3234 // PT_GNU_STACK, we generate the segment regardless.  Otherwise, we
3235 // don't generate a stack note.  When generating a object file, we
3236 // create a .note.GNU-stack section with the appropriate marking.
3237 // When generating an executable or shared library, we create a
3238 // PT_GNU_STACK segment.
3239
3240 void
3241 Layout::create_stack_segment()
3242 {
3243   bool is_stack_executable;
3244   if (parameters->options().is_execstack_set())
3245     {
3246       is_stack_executable = parameters->options().is_stack_executable();
3247       if (!is_stack_executable
3248           && this->input_requires_executable_stack_
3249           && parameters->options().warn_execstack())
3250         gold_warning(_("one or more inputs require executable stack, "
3251                        "but -z noexecstack was given"));
3252     }
3253   else if (!this->input_with_gnu_stack_note_
3254            && (!parameters->options().user_set_stack_size()
3255                || parameters->options().relocatable()))
3256     return;
3257   else
3258     {
3259       if (this->input_requires_executable_stack_)
3260         is_stack_executable = true;
3261       else if (this->input_without_gnu_stack_note_)
3262         is_stack_executable =
3263           parameters->target().is_default_stack_executable();
3264       else
3265         is_stack_executable = false;
3266     }
3267
3268   if (parameters->options().relocatable())
3269     {
3270       const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
3271       elfcpp::Elf_Xword flags = 0;
3272       if (is_stack_executable)
3273         flags |= elfcpp::SHF_EXECINSTR;
3274       this->make_output_section(name, elfcpp::SHT_PROGBITS, flags,
3275                                 ORDER_INVALID, false);
3276     }
3277   else
3278     {
3279       if (this->script_options_->saw_phdrs_clause())
3280         return;
3281       int flags = elfcpp::PF_R | elfcpp::PF_W;
3282       if (is_stack_executable)
3283         flags |= elfcpp::PF_X;
3284       Output_segment* seg =
3285         this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
3286       seg->set_size(parameters->options().stack_size());
3287       // BFD lets targets override this default alignment, but the only
3288       // targets that do so are ones that Gold does not support so far.
3289       seg->set_minimum_p_align(16);
3290     }
3291 }
3292
3293 // If --build-id was used, set up the build ID note.
3294
3295 void
3296 Layout::create_build_id()
3297 {
3298   if (!parameters->options().user_set_build_id())
3299     return;
3300
3301   const char* style = parameters->options().build_id();
3302   if (strcmp(style, "none") == 0)
3303     return;
3304
3305   // Set DESCSZ to the size of the note descriptor.  When possible,
3306   // set DESC to the note descriptor contents.
3307   size_t descsz;
3308   std::string desc;
3309   if (strcmp(style, "md5") == 0)
3310     descsz = 128 / 8;
3311   else if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0))
3312     descsz = 160 / 8;
3313   else if (strcmp(style, "uuid") == 0)
3314     {
3315 #ifndef __MINGW32__
3316       const size_t uuidsz = 128 / 8;
3317
3318       char buffer[uuidsz];
3319       memset(buffer, 0, uuidsz);
3320
3321       int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
3322       if (descriptor < 0)
3323         gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
3324                    strerror(errno));
3325       else
3326         {
3327           ssize_t got = ::read(descriptor, buffer, uuidsz);
3328           release_descriptor(descriptor, true);
3329           if (got < 0)
3330             gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
3331           else if (static_cast<size_t>(got) != uuidsz)
3332             gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
3333                        uuidsz, got);
3334         }
3335
3336       desc.assign(buffer, uuidsz);
3337       descsz = uuidsz;
3338 #else // __MINGW32__
3339       UUID uuid;
3340       typedef RPC_STATUS (RPC_ENTRY *UuidCreateFn)(UUID *Uuid);
3341
3342       HMODULE rpc_library = LoadLibrary("rpcrt4.dll");
3343       if (!rpc_library)
3344         gold_error(_("--build-id=uuid failed: could not load rpcrt4.dll"));
3345       else
3346         {
3347           UuidCreateFn uuid_create = reinterpret_cast<UuidCreateFn>(
3348               GetProcAddress(rpc_library, "UuidCreate"));
3349           if (!uuid_create)
3350             gold_error(_("--build-id=uuid failed: could not find UuidCreate"));
3351           else if (uuid_create(&uuid) != RPC_S_OK)
3352             gold_error(_("__build_id=uuid failed: call UuidCreate() failed"));
3353           FreeLibrary(rpc_library);
3354         }
3355       desc.assign(reinterpret_cast<const char *>(&uuid), sizeof(UUID));
3356       descsz = sizeof(UUID);
3357 #endif // __MINGW32__
3358     }
3359   else if (strncmp(style, "0x", 2) == 0)
3360     {
3361       hex_init();
3362       const char* p = style + 2;
3363       while (*p != '\0')
3364         {
3365           if (hex_p(p[0]) && hex_p(p[1]))
3366             {
3367               char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
3368               desc += c;
3369               p += 2;
3370             }
3371           else if (*p == '-' || *p == ':')
3372             ++p;
3373           else
3374             gold_fatal(_("--build-id argument '%s' not a valid hex number"),
3375                        style);
3376         }
3377       descsz = desc.size();
3378     }
3379   else
3380     gold_fatal(_("unrecognized --build-id argument '%s'"), style);
3381
3382   // Create the note.
3383   size_t trailing_padding;
3384   Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
3385                                          ".note.gnu.build-id", descsz, true,
3386                                          &trailing_padding);
3387   if (os == NULL)
3388     return;
3389
3390   if (!desc.empty())
3391     {
3392       // We know the value already, so we fill it in now.
3393       gold_assert(desc.size() == descsz);
3394
3395       Output_section_data* posd = new Output_data_const(desc, 4);
3396       os->add_output_section_data(posd);
3397
3398       if (trailing_padding != 0)
3399         {
3400           posd = new Output_data_zero_fill(trailing_padding, 0);
3401           os->add_output_section_data(posd);
3402         }
3403     }
3404   else
3405     {
3406       // We need to compute a checksum after we have completed the
3407       // link.
3408       gold_assert(trailing_padding == 0);
3409       this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
3410       os->add_output_section_data(this->build_id_note_);
3411     }
3412 }
3413
3414 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3415 // field of the former should point to the latter.  I'm not sure who
3416 // started this, but the GNU linker does it, and some tools depend
3417 // upon it.
3418
3419 void
3420 Layout::link_stabs_sections()
3421 {
3422   if (!this->have_stabstr_section_)
3423     return;
3424
3425   for (Section_list::iterator p = this->section_list_.begin();
3426        p != this->section_list_.end();
3427        ++p)
3428     {
3429       if ((*p)->type() != elfcpp::SHT_STRTAB)
3430         continue;
3431
3432       const char* name = (*p)->name();
3433       if (strncmp(name, ".stab", 5) != 0)
3434         continue;
3435
3436       size_t len = strlen(name);
3437       if (strcmp(name + len - 3, "str") != 0)
3438         continue;
3439
3440       std::string stab_name(name, len - 3);
3441       Output_section* stab_sec;
3442       stab_sec = this->find_output_section(stab_name.c_str());
3443       if (stab_sec != NULL)
3444         stab_sec->set_link_section(*p);
3445     }
3446 }
3447
3448 // Create .gnu_incremental_inputs and related sections needed
3449 // for the next run of incremental linking to check what has changed.
3450
3451 void
3452 Layout::create_incremental_info_sections(Symbol_table* symtab)
3453 {
3454   Incremental_inputs* incr = this->incremental_inputs_;
3455
3456   gold_assert(incr != NULL);
3457
3458   // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3459   incr->create_data_sections(symtab);
3460
3461   // Add the .gnu_incremental_inputs section.
3462   const char* incremental_inputs_name =
3463     this->namepool_.add(".gnu_incremental_inputs", false, NULL);
3464   Output_section* incremental_inputs_os =
3465     this->make_output_section(incremental_inputs_name,
3466                               elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0,
3467                               ORDER_INVALID, false);
3468   incremental_inputs_os->add_output_section_data(incr->inputs_section());
3469
3470   // Add the .gnu_incremental_symtab section.
3471   const char* incremental_symtab_name =
3472     this->namepool_.add(".gnu_incremental_symtab", false, NULL);
3473   Output_section* incremental_symtab_os =
3474     this->make_output_section(incremental_symtab_name,
3475                               elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0,
3476                               ORDER_INVALID, false);
3477   incremental_symtab_os->add_output_section_data(incr->symtab_section());
3478   incremental_symtab_os->set_entsize(4);
3479
3480   // Add the .gnu_incremental_relocs section.
3481   const char* incremental_relocs_name =
3482     this->namepool_.add(".gnu_incremental_relocs", false, NULL);
3483   Output_section* incremental_relocs_os =
3484     this->make_output_section(incremental_relocs_name,
3485                               elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0,
3486                               ORDER_INVALID, false);
3487   incremental_relocs_os->add_output_section_data(incr->relocs_section());
3488   incremental_relocs_os->set_entsize(incr->relocs_entsize());
3489
3490   // Add the .gnu_incremental_got_plt section.
3491   const char* incremental_got_plt_name =
3492     this->namepool_.add(".gnu_incremental_got_plt", false, NULL);
3493   Output_section* incremental_got_plt_os =
3494     this->make_output_section(incremental_got_plt_name,
3495                               elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0,
3496                               ORDER_INVALID, false);
3497   incremental_got_plt_os->add_output_section_data(incr->got_plt_section());
3498
3499   // Add the .gnu_incremental_strtab section.
3500   const char* incremental_strtab_name =
3501     this->namepool_.add(".gnu_incremental_strtab", false, NULL);
3502   Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name,
3503                                                         elfcpp::SHT_STRTAB, 0,
3504                                                         ORDER_INVALID, false);
3505   Output_data_strtab* strtab_data =
3506       new Output_data_strtab(incr->get_stringpool());
3507   incremental_strtab_os->add_output_section_data(strtab_data);
3508
3509   incremental_inputs_os->set_after_input_sections();
3510   incremental_symtab_os->set_after_input_sections();
3511   incremental_relocs_os->set_after_input_sections();
3512   incremental_got_plt_os->set_after_input_sections();
3513
3514   incremental_inputs_os->set_link_section(incremental_strtab_os);
3515   incremental_symtab_os->set_link_section(incremental_inputs_os);
3516   incremental_relocs_os->set_link_section(incremental_inputs_os);
3517   incremental_got_plt_os->set_link_section(incremental_inputs_os);
3518 }
3519
3520 // Return whether SEG1 should be before SEG2 in the output file.  This
3521 // is based entirely on the segment type and flags.  When this is
3522 // called the segment addresses have normally not yet been set.
3523
3524 bool
3525 Layout::segment_precedes(const Output_segment* seg1,
3526                          const Output_segment* seg2)
3527 {
3528   // In order to produce a stable ordering if we're called with the same pointer
3529   // return false.
3530   if (seg1 == seg2)
3531     return false;
3532
3533   elfcpp::Elf_Word type1 = seg1->type();
3534   elfcpp::Elf_Word type2 = seg2->type();
3535
3536   // The single PT_PHDR segment is required to precede any loadable
3537   // segment.  We simply make it always first.
3538   if (type1 == elfcpp::PT_PHDR)
3539     {
3540       gold_assert(type2 != elfcpp::PT_PHDR);
3541       return true;
3542     }
3543   if (type2 == elfcpp::PT_PHDR)
3544     return false;
3545
3546   // The single PT_INTERP segment is required to precede any loadable
3547   // segment.  We simply make it always second.
3548   if (type1 == elfcpp::PT_INTERP)
3549     {
3550       gold_assert(type2 != elfcpp::PT_INTERP);
3551       return true;
3552     }
3553   if (type2 == elfcpp::PT_INTERP)
3554     return false;
3555
3556   // We then put PT_LOAD segments before any other segments.
3557   if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
3558     return true;
3559   if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
3560     return false;
3561
3562   // We put the PT_TLS segment last except for the PT_GNU_RELRO
3563   // segment, because that is where the dynamic linker expects to find
3564   // it (this is just for efficiency; other positions would also work
3565   // correctly).
3566   if (type1 == elfcpp::PT_TLS
3567       && type2 != elfcpp::PT_TLS
3568       && type2 != elfcpp::PT_GNU_RELRO)
3569     return false;
3570   if (type2 == elfcpp::PT_TLS
3571       && type1 != elfcpp::PT_TLS
3572       && type1 != elfcpp::PT_GNU_RELRO)
3573     return true;
3574
3575   // We put the PT_GNU_RELRO segment last, because that is where the
3576   // dynamic linker expects to find it (as with PT_TLS, this is just
3577   // for efficiency).
3578   if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
3579     return false;
3580   if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
3581     return true;
3582
3583   const elfcpp::Elf_Word flags1 = seg1->flags();
3584   const elfcpp::Elf_Word flags2 = seg2->flags();
3585
3586   // The order of non-PT_LOAD segments is unimportant.  We simply sort
3587   // by the numeric segment type and flags values.  There should not
3588   // be more than one segment with the same type and flags, except
3589   // when a linker script specifies such.
3590   if (type1 != elfcpp::PT_LOAD)
3591     {
3592       if (type1 != type2)
3593         return type1 < type2;
3594       gold_assert(flags1 != flags2
3595                   || this->script_options_->saw_phdrs_clause());
3596       return flags1 < flags2;
3597     }
3598
3599   // If the addresses are set already, sort by load address.
3600   if (seg1->are_addresses_set())
3601     {
3602       if (!seg2->are_addresses_set())
3603         return true;
3604
3605       unsigned int section_count1 = seg1->output_section_count();
3606       unsigned int section_count2 = seg2->output_section_count();
3607       if (section_count1 == 0 && section_count2 > 0)
3608         return true;
3609       if (section_count1 > 0 && section_count2 == 0)
3610         return false;
3611
3612       uint64_t paddr1 = (seg1->are_addresses_set()
3613                          ? seg1->paddr()
3614                          : seg1->first_section_load_address());
3615       uint64_t paddr2 = (seg2->are_addresses_set()
3616                          ? seg2->paddr()
3617                          : seg2->first_section_load_address());
3618
3619       if (paddr1 != paddr2)
3620         return paddr1 < paddr2;
3621     }
3622   else if (seg2->are_addresses_set())
3623     return false;
3624
3625   // A segment which holds large data comes after a segment which does
3626   // not hold large data.
3627   if (seg1->is_large_data_segment())
3628     {
3629       if (!seg2->is_large_data_segment())
3630         return false;
3631     }
3632   else if (seg2->is_large_data_segment())
3633     return true;
3634
3635   // Otherwise, we sort PT_LOAD segments based on the flags.  Readonly
3636   // segments come before writable segments.  Then writable segments
3637   // with data come before writable segments without data.  Then
3638   // executable segments come before non-executable segments.  Then
3639   // the unlikely case of a non-readable segment comes before the
3640   // normal case of a readable segment.  If there are multiple
3641   // segments with the same type and flags, we require that the
3642   // address be set, and we sort by virtual address and then physical
3643   // address.
3644   if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
3645     return (flags1 & elfcpp::PF_W) == 0;
3646   if ((flags1 & elfcpp::PF_W) != 0
3647       && seg1->has_any_data_sections() != seg2->has_any_data_sections())
3648     return seg1->has_any_data_sections();
3649   if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
3650     return (flags1 & elfcpp::PF_X) != 0;
3651   if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
3652     return (flags1 & elfcpp::PF_R) == 0;
3653
3654   // We shouldn't get here--we shouldn't create segments which we
3655   // can't distinguish.  Unless of course we are using a weird linker
3656   // script or overlapping --section-start options.  We could also get
3657   // here if plugins want unique segments for subsets of sections.
3658   gold_assert(this->script_options_->saw_phdrs_clause()
3659               || parameters->options().any_section_start()
3660               || this->is_unique_segment_for_sections_specified()
3661               || parameters->options().text_unlikely_segment());
3662   return false;
3663 }
3664
3665 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3666
3667 static off_t
3668 align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
3669 {
3670   uint64_t unsigned_off = off;
3671   uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
3672                           | (addr & (abi_pagesize - 1)));
3673   if (aligned_off < unsigned_off)
3674     aligned_off += abi_pagesize;
3675   return aligned_off;
3676 }
3677
3678 // On targets where the text segment contains only executable code,
3679 // a non-executable segment is never the text segment.
3680
3681 static inline bool
3682 is_text_segment(const Target* target, const Output_segment* seg)
3683 {
3684   elfcpp::Elf_Xword flags = seg->flags();
3685   if ((flags & elfcpp::PF_W) != 0)
3686     return false;
3687   if ((flags & elfcpp::PF_X) == 0)
3688     return !target->isolate_execinstr();
3689   return true;
3690 }
3691
3692 // Set the file offsets of all the segments, and all the sections they
3693 // contain.  They have all been created.  LOAD_SEG must be laid out
3694 // first.  Return the offset of the data to follow.
3695
3696 off_t
3697 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
3698                             unsigned int* pshndx)
3699 {
3700   // Sort them into the final order.  We use a stable sort so that we
3701   // don't randomize the order of indistinguishable segments created
3702   // by linker scripts.
3703   std::stable_sort(this->segment_list_.begin(), this->segment_list_.end(),
3704                    Layout::Compare_segments(this));
3705
3706   // Find the PT_LOAD segments, and set their addresses and offsets
3707   // and their section's addresses and offsets.
3708   uint64_t start_addr;
3709   if (parameters->options().user_set_Ttext())
3710     start_addr = parameters->options().Ttext();
3711   else if (parameters->options().output_is_position_independent())
3712     start_addr = 0;
3713   else
3714     start_addr = target->default_text_segment_address();
3715
3716   uint64_t addr = start_addr;
3717   off_t off = 0;
3718
3719   // If LOAD_SEG is NULL, then the file header and segment headers
3720   // will not be loadable.  But they still need to be at offset 0 in
3721   // the file.  Set their offsets now.
3722   if (load_seg == NULL)
3723     {
3724       for (Data_list::iterator p = this->special_output_list_.begin();
3725            p != this->special_output_list_.end();
3726            ++p)
3727         {
3728           off = align_address(off, (*p)->addralign());
3729           (*p)->set_address_and_file_offset(0, off);
3730           off += (*p)->data_size();
3731         }
3732     }
3733
3734   unsigned int increase_relro = this->increase_relro_;
3735   if (this->script_options_->saw_sections_clause())
3736     increase_relro = 0;
3737
3738   const bool check_sections = parameters->options().check_sections();
3739   Output_segment* last_load_segment = NULL;
3740
3741   unsigned int shndx_begin = *pshndx;
3742   unsigned int shndx_load_seg = *pshndx;
3743
3744   for (Segment_list::iterator p = this->segment_list_.begin();
3745        p != this->segment_list_.end();
3746        ++p)
3747     {
3748       if ((*p)->type() == elfcpp::PT_LOAD)
3749         {
3750           if (target->isolate_execinstr())
3751             {
3752               // When we hit the segment that should contain the
3753               // file headers, reset the file offset so we place
3754               // it and subsequent segments appropriately.
3755               // We'll fix up the preceding segments below.
3756               if (load_seg == *p)
3757                 {
3758                   if (off == 0)
3759                     load_seg = NULL;
3760                   else
3761                     {
3762                       off = 0;
3763                       shndx_load_seg = *pshndx;
3764                     }
3765                 }
3766             }
3767           else
3768             {
3769               // Verify that the file headers fall into the first segment.
3770               if (load_seg != NULL && load_seg != *p)
3771                 gold_unreachable();
3772               load_seg = NULL;
3773             }
3774
3775           bool are_addresses_set = (*p)->are_addresses_set();
3776           if (are_addresses_set)
3777             {
3778               // When it comes to setting file offsets, we care about
3779               // the physical address.
3780               addr = (*p)->paddr();
3781             }
3782           else if (parameters->options().user_set_Ttext()
3783                    && (parameters->options().omagic()
3784                        || is_text_segment(target, *p)))
3785             {
3786               are_addresses_set = true;
3787             }
3788           else if (parameters->options().user_set_Trodata_segment()
3789                    && ((*p)->flags() & (elfcpp::PF_W | elfcpp::PF_X)) == 0)
3790             {
3791               addr = parameters->options().Trodata_segment();
3792               are_addresses_set = true;
3793             }
3794           else if (parameters->options().user_set_Tdata()
3795                    && ((*p)->flags() & elfcpp::PF_W) != 0
3796                    && (!parameters->options().user_set_Tbss()
3797                        || (*p)->has_any_data_sections()))
3798             {
3799               addr = parameters->options().Tdata();
3800               are_addresses_set = true;
3801             }
3802           else if (parameters->options().user_set_Tbss()
3803                    && ((*p)->flags() & elfcpp::PF_W) != 0
3804                    && !(*p)->has_any_data_sections())
3805             {
3806               addr = parameters->options().Tbss();
3807               are_addresses_set = true;
3808             }
3809
3810           uint64_t orig_addr = addr;
3811           uint64_t orig_off = off;
3812
3813           uint64_t aligned_addr = 0;
3814           uint64_t abi_pagesize = target->abi_pagesize();
3815           uint64_t common_pagesize = target->common_pagesize();
3816
3817           if (!parameters->options().nmagic()
3818               && !parameters->options().omagic())
3819             (*p)->set_minimum_p_align(abi_pagesize);
3820
3821           if (!are_addresses_set)
3822             {
3823               // Skip the address forward one page, maintaining the same
3824               // position within the page.  This lets us store both segments
3825               // overlapping on a single page in the file, but the loader will
3826               // put them on different pages in memory. We will revisit this
3827               // decision once we know the size of the segment.
3828
3829               uint64_t max_align = (*p)->maximum_alignment();
3830               if (max_align > abi_pagesize)
3831                 addr = align_address(addr, max_align);
3832               aligned_addr = addr;
3833
3834               if (load_seg == *p)
3835                 {
3836                   // This is the segment that will contain the file
3837                   // headers, so its offset will have to be exactly zero.
3838                   gold_assert(orig_off == 0);
3839
3840                   // If the target wants a fixed minimum distance from the
3841                   // text segment to the read-only segment, move up now.
3842                   uint64_t min_addr =
3843                     start_addr + (parameters->options().user_set_rosegment_gap()
3844                                   ? parameters->options().rosegment_gap()
3845                                   : target->rosegment_gap());
3846                   if (addr < min_addr)
3847                     addr = min_addr;
3848
3849                   // But this is not the first segment!  To make its
3850                   // address congruent with its offset, that address better
3851                   // be aligned to the ABI-mandated page size.
3852                   addr = align_address(addr, abi_pagesize);
3853                   aligned_addr = addr;
3854                 }
3855               else
3856                 {
3857                   if ((addr & (abi_pagesize - 1)) != 0)
3858                     addr = addr + abi_pagesize;
3859
3860                   off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3861                 }
3862             }
3863
3864           if (!parameters->options().nmagic()
3865               && !parameters->options().omagic())
3866             {
3867               // Here we are also taking care of the case when
3868               // the maximum segment alignment is larger than the page size.
3869               off = align_file_offset(off, addr,
3870                                       std::max(abi_pagesize,
3871                                                (*p)->maximum_alignment()));
3872             }
3873           else
3874             {
3875               // This is -N or -n with a section script which prevents
3876               // us from using a load segment.  We need to ensure that
3877               // the file offset is aligned to the alignment of the
3878               // segment.  This is because the linker script
3879               // implicitly assumed a zero offset.  If we don't align
3880               // here, then the alignment of the sections in the
3881               // linker script may not match the alignment of the
3882               // sections in the set_section_addresses call below,
3883               // causing an error about dot moving backward.
3884               off = align_address(off, (*p)->maximum_alignment());
3885             }
3886
3887           unsigned int shndx_hold = *pshndx;
3888           bool has_relro = false;
3889           uint64_t new_addr = (*p)->set_section_addresses(target, this,
3890                                                           false, addr,
3891                                                           &increase_relro,
3892                                                           &has_relro,
3893                                                           &off, pshndx);
3894
3895           // Now that we know the size of this segment, we may be able
3896           // to save a page in memory, at the cost of wasting some
3897           // file space, by instead aligning to the start of a new
3898           // page.  Here we use the real machine page size rather than
3899           // the ABI mandated page size.  If the segment has been
3900           // aligned so that the relro data ends at a page boundary,
3901           // we do not try to realign it.
3902
3903           if (!are_addresses_set
3904               && !has_relro
3905               && aligned_addr != addr
3906               && !parameters->incremental())
3907             {
3908               uint64_t first_off = (common_pagesize
3909                                     - (aligned_addr
3910                                        & (common_pagesize - 1)));
3911               uint64_t last_off = new_addr & (common_pagesize - 1);
3912               if (first_off > 0
3913                   && last_off > 0
3914                   && ((aligned_addr & ~ (common_pagesize - 1))
3915                       != (new_addr & ~ (common_pagesize - 1)))
3916                   && first_off + last_off <= common_pagesize)
3917                 {
3918                   *pshndx = shndx_hold;
3919                   addr = align_address(aligned_addr, common_pagesize);
3920                   addr = align_address(addr, (*p)->maximum_alignment());
3921                   if ((addr & (abi_pagesize - 1)) != 0)
3922                     addr = addr + abi_pagesize;
3923                   off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3924                   off = align_file_offset(off, addr, abi_pagesize);
3925
3926                   increase_relro = this->increase_relro_;
3927                   if (this->script_options_->saw_sections_clause())
3928                     increase_relro = 0;
3929                   has_relro = false;
3930
3931                   new_addr = (*p)->set_section_addresses(target, this,
3932                                                          true, addr,
3933                                                          &increase_relro,
3934                                                          &has_relro,
3935                                                          &off, pshndx);
3936                 }
3937             }
3938
3939           addr = new_addr;
3940
3941           // Implement --check-sections.  We know that the segments
3942           // are sorted by LMA.
3943           if (check_sections && last_load_segment != NULL)
3944             {
3945               gold_assert(last_load_segment->paddr() <= (*p)->paddr());
3946               if (last_load_segment->paddr() + last_load_segment->memsz()
3947                   > (*p)->paddr())
3948                 {
3949                   unsigned long long lb1 = last_load_segment->paddr();
3950                   unsigned long long le1 = lb1 + last_load_segment->memsz();
3951                   unsigned long long lb2 = (*p)->paddr();
3952                   unsigned long long le2 = lb2 + (*p)->memsz();
3953                   gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3954                                "[0x%llx -> 0x%llx]"),
3955                              lb1, le1, lb2, le2);
3956                 }
3957             }
3958           last_load_segment = *p;
3959         }
3960     }
3961
3962   if (load_seg != NULL && target->isolate_execinstr())
3963     {
3964       // Process the early segments again, setting their file offsets
3965       // so they land after the segments starting at LOAD_SEG.
3966       off = align_file_offset(off, 0, target->abi_pagesize());
3967
3968       this->reset_relax_output();
3969
3970       for (Segment_list::iterator p = this->segment_list_.begin();
3971            *p != load_seg;
3972            ++p)
3973         {
3974           if ((*p)->type() == elfcpp::PT_LOAD)
3975             {
3976               // We repeat the whole job of assigning addresses and
3977               // offsets, but we really only want to change the offsets and
3978               // must ensure that the addresses all come out the same as
3979               // they did the first time through.
3980               bool has_relro = false;
3981               const uint64_t old_addr = (*p)->vaddr();
3982               const uint64_t old_end = old_addr + (*p)->memsz();
3983               uint64_t new_addr = (*p)->set_section_addresses(target, this,
3984                                                               true, old_addr,
3985                                                               &increase_relro,
3986                                                               &has_relro,
3987                                                               &off,
3988                                                               &shndx_begin);
3989               gold_assert(new_addr == old_end);
3990             }
3991         }
3992
3993       gold_assert(shndx_begin == shndx_load_seg);
3994     }
3995
3996   // Handle the non-PT_LOAD segments, setting their offsets from their
3997   // section's offsets.
3998   for (Segment_list::iterator p = this->segment_list_.begin();
3999        p != this->segment_list_.end();
4000        ++p)
4001     {
4002       // PT_GNU_STACK was set up correctly when it was created.
4003       if ((*p)->type() != elfcpp::PT_LOAD
4004           && (*p)->type() != elfcpp::PT_GNU_STACK)
4005         (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO
4006                          ? increase_relro
4007                          : 0);
4008     }
4009
4010   // Set the TLS offsets for each section in the PT_TLS segment.
4011   if (this->tls_segment_ != NULL)
4012     this->tls_segment_->set_tls_offsets();
4013
4014   return off;
4015 }
4016
4017 // Set the offsets of all the allocated sections when doing a
4018 // relocatable link.  This does the same jobs as set_segment_offsets,
4019 // only for a relocatable link.
4020
4021 off_t
4022 Layout::set_relocatable_section_offsets(Output_data* file_header,
4023                                         unsigned int* pshndx)
4024 {
4025   off_t off = 0;
4026
4027   file_header->set_address_and_file_offset(0, 0);
4028   off += file_header->data_size();
4029
4030   for (Section_list::iterator p = this->section_list_.begin();
4031        p != this->section_list_.end();
4032        ++p)
4033     {
4034       // We skip unallocated sections here, except that group sections
4035       // have to come first.
4036       if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
4037           && (*p)->type() != elfcpp::SHT_GROUP)
4038         continue;
4039
4040       off = align_address(off, (*p)->addralign());
4041
4042       // The linker script might have set the address.
4043       if (!(*p)->is_address_valid())
4044         (*p)->set_address(0);
4045       (*p)->set_file_offset(off);
4046       (*p)->finalize_data_size();
4047       if ((*p)->type() != elfcpp::SHT_NOBITS)
4048         off += (*p)->data_size();
4049
4050       (*p)->set_out_shndx(*pshndx);
4051       ++*pshndx;
4052     }
4053
4054   return off;
4055 }
4056
4057 // Set the file offset of all the sections not associated with a
4058 // segment.
4059
4060 off_t
4061 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
4062 {
4063   off_t startoff = off;
4064   off_t maxoff = off;
4065
4066   for (Section_list::iterator p = this->unattached_section_list_.begin();
4067        p != this->unattached_section_list_.end();
4068        ++p)
4069     {
4070       // The symtab section is handled in create_symtab_sections.
4071       if (*p == this->symtab_section_)
4072         continue;
4073
4074       // If we've already set the data size, don't set it again.
4075       if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
4076         continue;
4077
4078       if (pass == BEFORE_INPUT_SECTIONS_PASS
4079           && (*p)->requires_postprocessing())
4080         {
4081           (*p)->create_postprocessing_buffer();
4082           this->any_postprocessing_sections_ = true;
4083         }
4084
4085       if (pass == BEFORE_INPUT_SECTIONS_PASS
4086           && (*p)->after_input_sections())
4087         continue;
4088       else if (pass == POSTPROCESSING_SECTIONS_PASS
4089                && (!(*p)->after_input_sections()
4090                    || (*p)->type() == elfcpp::SHT_STRTAB))
4091         continue;
4092       else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
4093                && (!(*p)->after_input_sections()
4094                    || (*p)->type() != elfcpp::SHT_STRTAB))
4095         continue;
4096
4097       if (!parameters->incremental_update())
4098         {
4099           off = align_address(off, (*p)->addralign());
4100           (*p)->set_file_offset(off);
4101           (*p)->finalize_data_size();
4102         }
4103       else
4104         {
4105           // Incremental update: allocate file space from free list.
4106           (*p)->pre_finalize_data_size();
4107           off_t current_size = (*p)->current_data_size();
4108           off = this->allocate(current_size, (*p)->addralign(), startoff);
4109           if (off == -1)
4110             {
4111               if (is_debugging_enabled(DEBUG_INCREMENTAL))
4112                 this->free_list_.dump();
4113               gold_assert((*p)->output_section() != NULL);
4114               gold_fallback(_("out of patch space for section %s; "
4115                               "relink with --incremental-full"),
4116                             (*p)->output_section()->name());
4117             }
4118           (*p)->set_file_offset(off);
4119           (*p)->finalize_data_size();
4120           if ((*p)->data_size() > current_size)
4121             {
4122               gold_assert((*p)->output_section() != NULL);
4123               gold_fallback(_("%s: section changed size; "
4124                               "relink with --incremental-full"),
4125                             (*p)->output_section()->name());
4126             }
4127           gold_debug(DEBUG_INCREMENTAL,
4128                      "set_section_offsets: %08lx %08lx %s",
4129                      static_cast<long>(off),
4130                      static_cast<long>((*p)->data_size()),
4131                      ((*p)->output_section() != NULL
4132                       ? (*p)->output_section()->name() : "(special)"));
4133         }
4134
4135       off += (*p)->data_size();
4136       if (off > maxoff)
4137         maxoff = off;
4138
4139       // At this point the name must be set.
4140       if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
4141         this->namepool_.add((*p)->name(), false, NULL);
4142     }
4143   return maxoff;
4144 }
4145
4146 // Set the section indexes of all the sections not associated with a
4147 // segment.
4148
4149 unsigned int
4150 Layout::set_section_indexes(unsigned int shndx)
4151 {
4152   for (Section_list::iterator p = this->unattached_section_list_.begin();
4153        p != this->unattached_section_list_.end();
4154        ++p)
4155     {
4156       if (!(*p)->has_out_shndx())
4157         {
4158           (*p)->set_out_shndx(shndx);
4159           ++shndx;
4160         }
4161     }
4162   return shndx;
4163 }
4164
4165 // Set the section addresses according to the linker script.  This is
4166 // only called when we see a SECTIONS clause.  This returns the
4167 // program segment which should hold the file header and segment
4168 // headers, if any.  It will return NULL if they should not be in a
4169 // segment.
4170
4171 Output_segment*
4172 Layout::set_section_addresses_from_script(Symbol_table* symtab)
4173 {
4174   Script_sections* ss = this->script_options_->script_sections();
4175   gold_assert(ss->saw_sections_clause());
4176   return this->script_options_->set_section_addresses(symtab, this);
4177 }
4178
4179 // Place the orphan sections in the linker script.
4180
4181 void
4182 Layout::place_orphan_sections_in_script()
4183 {
4184   Script_sections* ss = this->script_options_->script_sections();
4185   gold_assert(ss->saw_sections_clause());
4186
4187   // Place each orphaned output section in the script.
4188   for (Section_list::iterator p = this->section_list_.begin();
4189        p != this->section_list_.end();
4190        ++p)
4191     {
4192       if (!(*p)->found_in_sections_clause())
4193         ss->place_orphan(*p);
4194     }
4195 }
4196
4197 // Count the local symbols in the regular symbol table and the dynamic
4198 // symbol table, and build the respective string pools.
4199
4200 void
4201 Layout::count_local_symbols(const Task* task,
4202                             const Input_objects* input_objects)
4203 {
4204   // First, figure out an upper bound on the number of symbols we'll
4205   // be inserting into each pool.  This helps us create the pools with
4206   // the right size, to avoid unnecessary hashtable resizing.
4207   unsigned int symbol_count = 0;
4208   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4209        p != input_objects->relobj_end();
4210        ++p)
4211     symbol_count += (*p)->local_symbol_count();
4212
4213   // Go from "upper bound" to "estimate."  We overcount for two
4214   // reasons: we double-count symbols that occur in more than one
4215   // object file, and we count symbols that are dropped from the
4216   // output.  Add it all together and assume we overcount by 100%.
4217   symbol_count /= 2;
4218
4219   // We assume all symbols will go into both the sympool and dynpool.
4220   this->sympool_.reserve(symbol_count);
4221   this->dynpool_.reserve(symbol_count);
4222
4223   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4224        p != input_objects->relobj_end();
4225        ++p)
4226     {
4227       Task_lock_obj<Object> tlo(task, *p);
4228       (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
4229     }
4230 }
4231
4232 // Create the symbol table sections.  Here we also set the final
4233 // values of the symbols.  At this point all the loadable sections are
4234 // fully laid out.  SHNUM is the number of sections so far.
4235
4236 void
4237 Layout::create_symtab_sections(const Input_objects* input_objects,
4238                                Symbol_table* symtab,
4239                                unsigned int shnum,
4240                                off_t* poff,
4241                                unsigned int local_dynamic_count)
4242 {
4243   int symsize;
4244   unsigned int align;
4245   if (parameters->target().get_size() == 32)
4246     {
4247       symsize = elfcpp::Elf_sizes<32>::sym_size;
4248       align = 4;
4249     }
4250   else if (parameters->target().get_size() == 64)
4251     {
4252       symsize = elfcpp::Elf_sizes<64>::sym_size;
4253       align = 8;
4254     }
4255   else
4256     gold_unreachable();
4257
4258   // Compute file offsets relative to the start of the symtab section.
4259   off_t off = 0;
4260
4261   // Save space for the dummy symbol at the start of the section.  We
4262   // never bother to write this out--it will just be left as zero.
4263   off += symsize;
4264   unsigned int local_symbol_index = 1;
4265
4266   // Add STT_SECTION symbols for each Output section which needs one.
4267   for (Section_list::iterator p = this->section_list_.begin();
4268        p != this->section_list_.end();
4269        ++p)
4270     {
4271       if (!(*p)->needs_symtab_index())
4272         (*p)->set_symtab_index(-1U);
4273       else
4274         {
4275           (*p)->set_symtab_index(local_symbol_index);
4276           ++local_symbol_index;
4277           off += symsize;
4278         }
4279     }
4280
4281   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4282        p != input_objects->relobj_end();
4283        ++p)
4284     {
4285       unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
4286                                                         off, symtab);
4287       off += (index - local_symbol_index) * symsize;
4288       local_symbol_index = index;
4289     }
4290
4291   unsigned int local_symcount = local_symbol_index;
4292   gold_assert(static_cast<off_t>(local_symcount * symsize) == off);
4293
4294   off_t dynoff;
4295   size_t dyncount;
4296   if (this->dynsym_section_ == NULL)
4297     {
4298       dynoff = 0;
4299       dyncount = 0;
4300     }
4301   else
4302     {
4303       off_t locsize = local_dynamic_count * this->dynsym_section_->entsize();
4304       dynoff = this->dynsym_section_->offset() + locsize;
4305       dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
4306       gold_assert(static_cast<off_t>(dyncount * symsize)
4307                   == this->dynsym_section_->data_size() - locsize);
4308     }
4309
4310   off_t global_off = off;
4311   off = symtab->finalize(off, dynoff, local_dynamic_count, dyncount,
4312                          &this->sympool_, &local_symcount);
4313
4314   if (!parameters->options().strip_all())
4315     {
4316       this->sympool_.set_string_offsets();
4317
4318       const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
4319       Output_section* osymtab = this->make_output_section(symtab_name,
4320                                                           elfcpp::SHT_SYMTAB,
4321                                                           0, ORDER_INVALID,
4322                                                           false);
4323       this->symtab_section_ = osymtab;
4324
4325       Output_section_data* pos = new Output_data_fixed_space(off, align,
4326                                                              "** symtab");
4327       osymtab->add_output_section_data(pos);
4328
4329       // We generate a .symtab_shndx section if we have more than
4330       // SHN_LORESERVE sections.  Technically it is possible that we
4331       // don't need one, because it is possible that there are no
4332       // symbols in any of sections with indexes larger than
4333       // SHN_LORESERVE.  That is probably unusual, though, and it is
4334       // easier to always create one than to compute section indexes
4335       // twice (once here, once when writing out the symbols).
4336       if (shnum >= elfcpp::SHN_LORESERVE)
4337         {
4338           const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
4339                                                                false, NULL);
4340           Output_section* osymtab_xindex =
4341             this->make_output_section(symtab_xindex_name,
4342                                       elfcpp::SHT_SYMTAB_SHNDX, 0,
4343                                       ORDER_INVALID, false);
4344
4345           size_t symcount = off / symsize;
4346           this->symtab_xindex_ = new Output_symtab_xindex(symcount);
4347
4348           osymtab_xindex->add_output_section_data(this->symtab_xindex_);
4349
4350           osymtab_xindex->set_link_section(osymtab);
4351           osymtab_xindex->set_addralign(4);
4352           osymtab_xindex->set_entsize(4);
4353
4354           osymtab_xindex->set_after_input_sections();
4355
4356           // This tells the driver code to wait until the symbol table
4357           // has written out before writing out the postprocessing
4358           // sections, including the .symtab_shndx section.
4359           this->any_postprocessing_sections_ = true;
4360         }
4361
4362       const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
4363       Output_section* ostrtab = this->make_output_section(strtab_name,
4364                                                           elfcpp::SHT_STRTAB,
4365                                                           0, ORDER_INVALID,
4366                                                           false);
4367
4368       Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
4369       ostrtab->add_output_section_data(pstr);
4370
4371       off_t symtab_off;
4372       if (!parameters->incremental_update())
4373         symtab_off = align_address(*poff, align);
4374       else
4375         {
4376           symtab_off = this->allocate(off, align, *poff);
4377           if (off == -1)
4378             gold_fallback(_("out of patch space for symbol table; "
4379                             "relink with --incremental-full"));
4380           gold_debug(DEBUG_INCREMENTAL,
4381                      "create_symtab_sections: %08lx %08lx .symtab",
4382                      static_cast<long>(symtab_off),
4383                      static_cast<long>(off));
4384         }
4385
4386       symtab->set_file_offset(symtab_off + global_off);
4387       osymtab->set_file_offset(symtab_off);
4388       osymtab->finalize_data_size();
4389       osymtab->set_link_section(ostrtab);
4390       osymtab->set_info(local_symcount);
4391       osymtab->set_entsize(symsize);
4392
4393       if (symtab_off + off > *poff)
4394         *poff = symtab_off + off;
4395     }
4396 }
4397
4398 // Create the .shstrtab section, which holds the names of the
4399 // sections.  At the time this is called, we have created all the
4400 // output sections except .shstrtab itself.
4401
4402 Output_section*
4403 Layout::create_shstrtab()
4404 {
4405   // FIXME: We don't need to create a .shstrtab section if we are
4406   // stripping everything.
4407
4408   const char* name = this->namepool_.add(".shstrtab", false, NULL);
4409
4410   Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0,
4411                                                  ORDER_INVALID, false);
4412
4413   if (strcmp(parameters->options().compress_debug_sections(), "none") != 0)
4414     {
4415       // We can't write out this section until we've set all the
4416       // section names, and we don't set the names of compressed
4417       // output sections until relocations are complete.  FIXME: With
4418       // the current names we use, this is unnecessary.
4419       os->set_after_input_sections();
4420     }
4421
4422   Output_section_data* posd = new Output_data_strtab(&this->namepool_);
4423   os->add_output_section_data(posd);
4424
4425   return os;
4426 }
4427
4428 // Create the section headers.  SIZE is 32 or 64.  OFF is the file
4429 // offset.
4430
4431 void
4432 Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
4433 {
4434   Output_section_headers* oshdrs;
4435   oshdrs = new Output_section_headers(this,
4436                                       &this->segment_list_,
4437                                       &this->section_list_,
4438                                       &this->unattached_section_list_,
4439                                       &this->namepool_,
4440                                       shstrtab_section);
4441   off_t off;
4442   if (!parameters->incremental_update())
4443     off = align_address(*poff, oshdrs->addralign());
4444   else
4445     {
4446       oshdrs->pre_finalize_data_size();
4447       off = this->allocate(oshdrs->data_size(), oshdrs->addralign(), *poff);
4448       if (off == -1)
4449           gold_fallback(_("out of patch space for section header table; "
4450                           "relink with --incremental-full"));
4451       gold_debug(DEBUG_INCREMENTAL,
4452                  "create_shdrs: %08lx %08lx (section header table)",
4453                  static_cast<long>(off),
4454                  static_cast<long>(off + oshdrs->data_size()));
4455     }
4456   oshdrs->set_address_and_file_offset(0, off);
4457   off += oshdrs->data_size();
4458   if (off > *poff)
4459     *poff = off;
4460   this->section_headers_ = oshdrs;
4461 }
4462
4463 // Count the allocated sections.
4464
4465 size_t
4466 Layout::allocated_output_section_count() const
4467 {
4468   size_t section_count = 0;
4469   for (Segment_list::const_iterator p = this->segment_list_.begin();
4470        p != this->segment_list_.end();
4471        ++p)
4472     section_count += (*p)->output_section_count();
4473   return section_count;
4474 }
4475
4476 // Create the dynamic symbol table.
4477 // *PLOCAL_DYNAMIC_COUNT will be set to the number of local symbols
4478 // from input objects, and *PFORCED_LOCAL_DYNAMIC_COUNT will be set
4479 // to the number of global symbols that have been forced local.
4480 // We need to remember the former because the forced-local symbols are
4481 // written along with the global symbols in Symtab::write_globals().
4482
4483 void
4484 Layout::create_dynamic_symtab(const Input_objects* input_objects,
4485                               Symbol_table* symtab,
4486                               Output_section** pdynstr,
4487                               unsigned int* plocal_dynamic_count,
4488                               unsigned int* pforced_local_dynamic_count,
4489                               std::vector<Symbol*>* pdynamic_symbols,
4490                               Versions* pversions)
4491 {
4492   // Count all the symbols in the dynamic symbol table, and set the
4493   // dynamic symbol indexes.
4494
4495   // Skip symbol 0, which is always all zeroes.
4496   unsigned int index = 1;
4497
4498   // Add STT_SECTION symbols for each Output section which needs one.
4499   for (Section_list::iterator p = this->section_list_.begin();
4500        p != this->section_list_.end();
4501        ++p)
4502     {
4503       if (!(*p)->needs_dynsym_index())
4504         (*p)->set_dynsym_index(-1U);
4505       else
4506         {
4507           (*p)->set_dynsym_index(index);
4508           ++index;
4509         }
4510     }
4511
4512   // Count the local symbols that need to go in the dynamic symbol table,
4513   // and set the dynamic symbol indexes.
4514   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4515        p != input_objects->relobj_end();
4516        ++p)
4517     {
4518       unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
4519       index = new_index;
4520     }
4521
4522   unsigned int local_symcount = index;
4523   unsigned int forced_local_count = 0;
4524
4525   index = symtab->set_dynsym_indexes(index, &forced_local_count,
4526                                      pdynamic_symbols, &this->dynpool_,
4527                                      pversions);
4528
4529   *plocal_dynamic_count = local_symcount;
4530   *pforced_local_dynamic_count = forced_local_count;
4531
4532   int symsize;
4533   unsigned int align;
4534   const int size = parameters->target().get_size();
4535   if (size == 32)
4536     {
4537       symsize = elfcpp::Elf_sizes<32>::sym_size;
4538       align = 4;
4539     }
4540   else if (size == 64)
4541     {
4542       symsize = elfcpp::Elf_sizes<64>::sym_size;
4543       align = 8;
4544     }
4545   else
4546     gold_unreachable();
4547
4548   // Create the dynamic symbol table section.
4549
4550   Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
4551                                                        elfcpp::SHT_DYNSYM,
4552                                                        elfcpp::SHF_ALLOC,
4553                                                        false,
4554                                                        ORDER_DYNAMIC_LINKER,
4555                                                        false, false, false);
4556
4557   // Check for NULL as a linker script may discard .dynsym.
4558   if (dynsym != NULL)
4559     {
4560       Output_section_data* odata = new Output_data_fixed_space(index * symsize,
4561                                                                align,
4562                                                                "** dynsym");
4563       dynsym->add_output_section_data(odata);
4564
4565       dynsym->set_info(local_symcount + forced_local_count);
4566       dynsym->set_entsize(symsize);
4567       dynsym->set_addralign(align);
4568
4569       this->dynsym_section_ = dynsym;
4570     }
4571
4572   Output_data_dynamic* const odyn = this->dynamic_data_;
4573   if (odyn != NULL)
4574     {
4575       odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
4576       odyn->add_constant(elfcpp::DT_SYMENT, symsize);
4577     }
4578
4579   // If there are more than SHN_LORESERVE allocated sections, we
4580   // create a .dynsym_shndx section.  It is possible that we don't
4581   // need one, because it is possible that there are no dynamic
4582   // symbols in any of the sections with indexes larger than
4583   // SHN_LORESERVE.  This is probably unusual, though, and at this
4584   // time we don't know the actual section indexes so it is
4585   // inconvenient to check.
4586   if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
4587     {
4588       Output_section* dynsym_xindex =
4589         this->choose_output_section(NULL, ".dynsym_shndx",
4590                                     elfcpp::SHT_SYMTAB_SHNDX,
4591                                     elfcpp::SHF_ALLOC,
4592                                     false, ORDER_DYNAMIC_LINKER, false, false,
4593                                     false);
4594
4595       if (dynsym_xindex != NULL)
4596         {
4597           this->dynsym_xindex_ = new Output_symtab_xindex(index);
4598
4599           dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
4600
4601           dynsym_xindex->set_link_section(dynsym);
4602           dynsym_xindex->set_addralign(4);
4603           dynsym_xindex->set_entsize(4);
4604
4605           dynsym_xindex->set_after_input_sections();
4606
4607           // This tells the driver code to wait until the symbol table
4608           // has written out before writing out the postprocessing
4609           // sections, including the .dynsym_shndx section.
4610           this->any_postprocessing_sections_ = true;
4611         }
4612     }
4613
4614   // Create the dynamic string table section.
4615
4616   Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
4617                                                        elfcpp::SHT_STRTAB,
4618                                                        elfcpp::SHF_ALLOC,
4619                                                        false,
4620                                                        ORDER_DYNAMIC_LINKER,
4621                                                        false, false, false);
4622   *pdynstr = dynstr;
4623   if (dynstr != NULL)
4624     {
4625       Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
4626       dynstr->add_output_section_data(strdata);
4627
4628       if (dynsym != NULL)
4629         dynsym->set_link_section(dynstr);
4630       if (this->dynamic_section_ != NULL)
4631         this->dynamic_section_->set_link_section(dynstr);
4632
4633       if (odyn != NULL)
4634         {
4635           odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
4636           odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
4637         }
4638     }
4639
4640   // Create the hash tables.  The Gnu-style hash table must be
4641   // built first, because it changes the order of the symbols
4642   // in the dynamic symbol table.
4643
4644   if (strcmp(parameters->options().hash_style(), "gnu") == 0
4645       || strcmp(parameters->options().hash_style(), "both") == 0)
4646     {
4647       unsigned char* phash;
4648       unsigned int hashlen;
4649       Dynobj::create_gnu_hash_table(*pdynamic_symbols,
4650                                     local_symcount + forced_local_count,
4651                                     &phash, &hashlen);
4652
4653       Output_section* hashsec =
4654         this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH,
4655                                     elfcpp::SHF_ALLOC, false,
4656                                     ORDER_DYNAMIC_LINKER, false, false,
4657                                     false);
4658
4659       Output_section_data* hashdata = new Output_data_const_buffer(phash,
4660                                                                    hashlen,
4661                                                                    align,
4662                                                                    "** hash");
4663       if (hashsec != NULL && hashdata != NULL)
4664         hashsec->add_output_section_data(hashdata);
4665
4666       if (hashsec != NULL)
4667         {
4668           if (dynsym != NULL)
4669             hashsec->set_link_section(dynsym);
4670
4671           // For a 64-bit target, the entries in .gnu.hash do not have
4672           // a uniform size, so we only set the entry size for a
4673           // 32-bit target.
4674           if (parameters->target().get_size() == 32)
4675             hashsec->set_entsize(4);
4676
4677           if (odyn != NULL)
4678             odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
4679         }
4680     }
4681
4682   if (strcmp(parameters->options().hash_style(), "sysv") == 0
4683       || strcmp(parameters->options().hash_style(), "both") == 0)
4684     {
4685       unsigned char* phash;
4686       unsigned int hashlen;
4687       Dynobj::create_elf_hash_table(*pdynamic_symbols,
4688                                     local_symcount + forced_local_count,
4689                                     &phash, &hashlen);
4690
4691       Output_section* hashsec =
4692         this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH,
4693                                     elfcpp::SHF_ALLOC, false,
4694                                     ORDER_DYNAMIC_LINKER, false, false,
4695                                     false);
4696
4697       Output_section_data* hashdata = new Output_data_const_buffer(phash,
4698                                                                    hashlen,
4699                                                                    align,
4700                                                                    "** hash");
4701       if (hashsec != NULL && hashdata != NULL)
4702         hashsec->add_output_section_data(hashdata);
4703
4704       if (hashsec != NULL)
4705         {
4706           if (dynsym != NULL)
4707             hashsec->set_link_section(dynsym);
4708           hashsec->set_entsize(parameters->target().hash_entry_size() / 8);
4709         }
4710
4711       if (odyn != NULL)
4712         odyn->add_section_address(elfcpp::DT_HASH, hashsec);
4713     }
4714 }
4715
4716 // Assign offsets to each local portion of the dynamic symbol table.
4717
4718 void
4719 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
4720 {
4721   Output_section* dynsym = this->dynsym_section_;
4722   if (dynsym == NULL)
4723     return;
4724
4725   off_t off = dynsym->offset();
4726
4727   // Skip the dummy symbol at the start of the section.
4728   off += dynsym->entsize();
4729
4730   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4731        p != input_objects->relobj_end();
4732        ++p)
4733     {
4734       unsigned int count = (*p)->set_local_dynsym_offset(off);
4735       off += count * dynsym->entsize();
4736     }
4737 }
4738
4739 // Create the version sections.
4740
4741 void
4742 Layout::create_version_sections(const Versions* versions,
4743                                 const Symbol_table* symtab,
4744                                 unsigned int local_symcount,
4745                                 const std::vector<Symbol*>& dynamic_symbols,
4746                                 const Output_section* dynstr)
4747 {
4748   if (!versions->any_defs() && !versions->any_needs())
4749     return;
4750
4751   switch (parameters->size_and_endianness())
4752     {
4753 #ifdef HAVE_TARGET_32_LITTLE
4754     case Parameters::TARGET_32_LITTLE:
4755       this->sized_create_version_sections<32, false>(versions, symtab,
4756                                                      local_symcount,
4757                                                      dynamic_symbols, dynstr);
4758       break;
4759 #endif
4760 #ifdef HAVE_TARGET_32_BIG
4761     case Parameters::TARGET_32_BIG:
4762       this->sized_create_version_sections<32, true>(versions, symtab,
4763                                                     local_symcount,
4764                                                     dynamic_symbols, dynstr);
4765       break;
4766 #endif
4767 #ifdef HAVE_TARGET_64_LITTLE
4768     case Parameters::TARGET_64_LITTLE:
4769       this->sized_create_version_sections<64, false>(versions, symtab,
4770                                                      local_symcount,
4771                                                      dynamic_symbols, dynstr);
4772       break;
4773 #endif
4774 #ifdef HAVE_TARGET_64_BIG
4775     case Parameters::TARGET_64_BIG:
4776       this->sized_create_version_sections<64, true>(versions, symtab,
4777                                                     local_symcount,
4778                                                     dynamic_symbols, dynstr);
4779       break;
4780 #endif
4781     default:
4782       gold_unreachable();
4783     }
4784 }
4785
4786 // Create the version sections, sized version.
4787
4788 template<int size, bool big_endian>
4789 void
4790 Layout::sized_create_version_sections(
4791     const Versions* versions,
4792     const Symbol_table* symtab,
4793     unsigned int local_symcount,
4794     const std::vector<Symbol*>& dynamic_symbols,
4795     const Output_section* dynstr)
4796 {
4797   Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
4798                                                      elfcpp::SHT_GNU_versym,
4799                                                      elfcpp::SHF_ALLOC,
4800                                                      false,
4801                                                      ORDER_DYNAMIC_LINKER,
4802                                                      false, false, false);
4803
4804   // Check for NULL since a linker script may discard this section.
4805   if (vsec != NULL)
4806     {
4807       unsigned char* vbuf;
4808       unsigned int vsize;
4809       versions->symbol_section_contents<size, big_endian>(symtab,
4810                                                           &this->dynpool_,
4811                                                           local_symcount,
4812                                                           dynamic_symbols,
4813                                                           &vbuf, &vsize);
4814
4815       Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
4816                                                                 "** versions");
4817
4818       vsec->add_output_section_data(vdata);
4819       vsec->set_entsize(2);
4820       vsec->set_link_section(this->dynsym_section_);
4821     }
4822
4823   Output_data_dynamic* const odyn = this->dynamic_data_;
4824   if (odyn != NULL && vsec != NULL)
4825     odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
4826
4827   if (versions->any_defs())
4828     {
4829       Output_section* vdsec;
4830       vdsec = this->choose_output_section(NULL, ".gnu.version_d",
4831                                           elfcpp::SHT_GNU_verdef,
4832                                           elfcpp::SHF_ALLOC,
4833                                           false, ORDER_DYNAMIC_LINKER, false,
4834                                           false, false);
4835
4836       if (vdsec != NULL)
4837         {
4838           unsigned char* vdbuf;
4839           unsigned int vdsize;
4840           unsigned int vdentries;
4841           versions->def_section_contents<size, big_endian>(&this->dynpool_,
4842                                                            &vdbuf, &vdsize,
4843                                                            &vdentries);
4844
4845           Output_section_data* vddata =
4846             new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
4847
4848           vdsec->add_output_section_data(vddata);
4849           vdsec->set_link_section(dynstr);
4850           vdsec->set_info(vdentries);
4851
4852           if (odyn != NULL)
4853             {
4854               odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
4855               odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
4856             }
4857         }
4858     }
4859
4860   if (versions->any_needs())
4861     {
4862       Output_section* vnsec;
4863       vnsec = this->choose_output_section(NULL, ".gnu.version_r",
4864                                           elfcpp::SHT_GNU_verneed,
4865                                           elfcpp::SHF_ALLOC,
4866                                           false, ORDER_DYNAMIC_LINKER, false,
4867                                           false, false);
4868
4869       if (vnsec != NULL)
4870         {
4871           unsigned char* vnbuf;
4872           unsigned int vnsize;
4873           unsigned int vnentries;
4874           versions->need_section_contents<size, big_endian>(&this->dynpool_,
4875                                                             &vnbuf, &vnsize,
4876                                                             &vnentries);
4877
4878           Output_section_data* vndata =
4879             new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
4880
4881           vnsec->add_output_section_data(vndata);
4882           vnsec->set_link_section(dynstr);
4883           vnsec->set_info(vnentries);
4884
4885           if (odyn != NULL)
4886             {
4887               odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
4888               odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
4889             }
4890         }
4891     }
4892 }
4893
4894 // Create the .interp section and PT_INTERP segment.
4895
4896 void
4897 Layout::create_interp(const Target* target)
4898 {
4899   gold_assert(this->interp_segment_ == NULL);
4900
4901   const char* interp = parameters->options().dynamic_linker();
4902   if (interp == NULL)
4903     {
4904       interp = target->dynamic_linker();
4905       gold_assert(interp != NULL);
4906     }
4907
4908   size_t len = strlen(interp) + 1;
4909
4910   Output_section_data* odata = new Output_data_const(interp, len, 1);
4911
4912   Output_section* osec = this->choose_output_section(NULL, ".interp",
4913                                                      elfcpp::SHT_PROGBITS,
4914                                                      elfcpp::SHF_ALLOC,
4915                                                      false, ORDER_INTERP,
4916                                                      false, false, false);
4917   if (osec != NULL)
4918     osec->add_output_section_data(odata);
4919 }
4920
4921 // Add dynamic tags for the PLT and the dynamic relocs.  This is
4922 // called by the target-specific code.  This does nothing if not doing
4923 // a dynamic link.
4924
4925 // USE_REL is true for REL relocs rather than RELA relocs.
4926
4927 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
4928
4929 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
4930 // and we also set DT_PLTREL.  We use PLT_REL's output section, since
4931 // some targets have multiple reloc sections in PLT_REL.
4932
4933 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
4934 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.  Again we use the output
4935 // section.
4936
4937 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
4938 // executable.
4939
4940 void
4941 Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
4942                                 const Output_data* plt_rel,
4943                                 const Output_data_reloc_generic* dyn_rel,
4944                                 bool add_debug, bool dynrel_includes_plt)
4945 {
4946   Output_data_dynamic* odyn = this->dynamic_data_;
4947   if (odyn == NULL)
4948     return;
4949
4950   if (plt_got != NULL && plt_got->output_section() != NULL)
4951     odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got);
4952
4953   if (plt_rel != NULL && plt_rel->output_section() != NULL)
4954     {
4955       odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section());
4956       odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section());
4957       odyn->add_constant(elfcpp::DT_PLTREL,
4958                          use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA);
4959     }
4960
4961   if ((dyn_rel != NULL && dyn_rel->output_section() != NULL)
4962       || (dynrel_includes_plt
4963           && plt_rel != NULL
4964           && plt_rel->output_section() != NULL))
4965     {
4966       bool have_dyn_rel = dyn_rel != NULL && dyn_rel->output_section() != NULL;
4967       bool have_plt_rel = plt_rel != NULL && plt_rel->output_section() != NULL;
4968       odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
4969                                 (have_dyn_rel
4970                                  ? dyn_rel->output_section()
4971                                  : plt_rel->output_section()));
4972       elfcpp::DT size_tag = use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ;
4973       if (have_dyn_rel && have_plt_rel && dynrel_includes_plt)
4974         odyn->add_section_size(size_tag,
4975                                dyn_rel->output_section(),
4976                                plt_rel->output_section());
4977       else if (have_dyn_rel)
4978         odyn->add_section_size(size_tag, dyn_rel->output_section());
4979       else
4980         odyn->add_section_size(size_tag, plt_rel->output_section());
4981       const int size = parameters->target().get_size();
4982       elfcpp::DT rel_tag;
4983       int rel_size;
4984       if (use_rel)
4985         {
4986           rel_tag = elfcpp::DT_RELENT;
4987           if (size == 32)
4988             rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size;
4989           else if (size == 64)
4990             rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size;
4991           else
4992             gold_unreachable();
4993         }
4994       else
4995         {
4996           rel_tag = elfcpp::DT_RELAENT;
4997           if (size == 32)
4998             rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size;
4999           else if (size == 64)
5000             rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size;
5001           else
5002             gold_unreachable();
5003         }
5004       odyn->add_constant(rel_tag, rel_size);
5005
5006       if (parameters->options().combreloc() && have_dyn_rel)
5007         {
5008           size_t c = dyn_rel->relative_reloc_count();
5009           if (c > 0)
5010             odyn->add_constant((use_rel
5011                                 ? elfcpp::DT_RELCOUNT
5012                                 : elfcpp::DT_RELACOUNT),
5013                                c);
5014         }
5015     }
5016
5017   if (add_debug && !parameters->options().shared())
5018     {
5019       // The value of the DT_DEBUG tag is filled in by the dynamic
5020       // linker at run time, and used by the debugger.
5021       odyn->add_constant(elfcpp::DT_DEBUG, 0);
5022     }
5023 }
5024
5025 void
5026 Layout::add_target_specific_dynamic_tag(elfcpp::DT tag, unsigned int val)
5027 {
5028   Output_data_dynamic* odyn = this->dynamic_data_;
5029   if (odyn == NULL)
5030     return;
5031   odyn->add_constant(tag, val);
5032 }
5033
5034 // Finish the .dynamic section and PT_DYNAMIC segment.
5035
5036 void
5037 Layout::finish_dynamic_section(const Input_objects* input_objects,
5038                                const Symbol_table* symtab)
5039 {
5040   if (!this->script_options_->saw_phdrs_clause()
5041       && this->dynamic_section_ != NULL)
5042     {
5043       Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
5044                                                        (elfcpp::PF_R
5045                                                         | elfcpp::PF_W));
5046       oseg->add_output_section_to_nonload(this->dynamic_section_,
5047                                           elfcpp::PF_R | elfcpp::PF_W);
5048     }
5049
5050   Output_data_dynamic* const odyn = this->dynamic_data_;
5051   if (odyn == NULL)
5052     return;
5053
5054   for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
5055        p != input_objects->dynobj_end();
5056        ++p)
5057     {
5058       if (!(*p)->is_needed() && (*p)->as_needed())
5059         {
5060           // This dynamic object was linked with --as-needed, but it
5061           // is not needed.
5062           continue;
5063         }
5064
5065       odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
5066     }
5067
5068   if (parameters->options().shared())
5069     {
5070       const char* soname = parameters->options().soname();
5071       if (soname != NULL)
5072         odyn->add_string(elfcpp::DT_SONAME, soname);
5073     }
5074
5075   Symbol* sym = symtab->lookup(parameters->options().init());
5076   if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
5077     odyn->add_symbol(elfcpp::DT_INIT, sym);
5078
5079   sym = symtab->lookup(parameters->options().fini());
5080   if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
5081     odyn->add_symbol(elfcpp::DT_FINI, sym);
5082
5083   // Look for .init_array, .preinit_array and .fini_array by checking
5084   // section types.
5085   for(Layout::Section_list::const_iterator p = this->section_list_.begin();
5086       p != this->section_list_.end();
5087       ++p)
5088     switch((*p)->type())
5089       {
5090       case elfcpp::SHT_FINI_ARRAY:
5091         odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p);
5092         odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p);
5093         break;
5094       case elfcpp::SHT_INIT_ARRAY:
5095         odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p);
5096         odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p);
5097         break;
5098       case elfcpp::SHT_PREINIT_ARRAY:
5099         odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p);
5100         odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p);
5101         break;
5102       default:
5103         break;
5104       }
5105
5106   // Add a DT_RPATH entry if needed.
5107   const General_options::Dir_list& rpath(parameters->options().rpath());
5108   if (!rpath.empty())
5109     {
5110       std::string rpath_val;
5111       for (General_options::Dir_list::const_iterator p = rpath.begin();
5112            p != rpath.end();
5113            ++p)
5114         {
5115           if (rpath_val.empty())
5116             rpath_val = p->name();
5117           else
5118             {
5119               // Eliminate duplicates.
5120               General_options::Dir_list::const_iterator q;
5121               for (q = rpath.begin(); q != p; ++q)
5122                 if (q->name() == p->name())
5123                   break;
5124               if (q == p)
5125                 {
5126                   rpath_val += ':';
5127                   rpath_val += p->name();
5128                 }
5129             }
5130         }
5131
5132       if (!parameters->options().enable_new_dtags())
5133         odyn->add_string(elfcpp::DT_RPATH, rpath_val);
5134       else
5135         odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
5136     }
5137
5138   // Look for text segments that have dynamic relocations.
5139   bool have_textrel = false;
5140   if (!this->script_options_->saw_sections_clause())
5141     {
5142       for (Segment_list::const_iterator p = this->segment_list_.begin();
5143            p != this->segment_list_.end();
5144            ++p)
5145         {
5146           if ((*p)->type() == elfcpp::PT_LOAD
5147               && ((*p)->flags() & elfcpp::PF_W) == 0
5148               && (*p)->has_dynamic_reloc())
5149             {
5150               have_textrel = true;
5151               break;
5152             }
5153         }
5154     }
5155   else
5156     {
5157       // We don't know the section -> segment mapping, so we are
5158       // conservative and just look for readonly sections with
5159       // relocations.  If those sections wind up in writable segments,
5160       // then we have created an unnecessary DT_TEXTREL entry.
5161       for (Section_list::const_iterator p = this->section_list_.begin();
5162            p != this->section_list_.end();
5163            ++p)
5164         {
5165           if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
5166               && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
5167               && (*p)->has_dynamic_reloc())
5168             {
5169               have_textrel = true;
5170               break;
5171             }
5172         }
5173     }
5174
5175   if (parameters->options().filter() != NULL)
5176     odyn->add_string(elfcpp::DT_FILTER, parameters->options().filter());
5177   if (parameters->options().any_auxiliary())
5178     {
5179       for (options::String_set::const_iterator p =
5180              parameters->options().auxiliary_begin();
5181            p != parameters->options().auxiliary_end();
5182            ++p)
5183         odyn->add_string(elfcpp::DT_AUXILIARY, *p);
5184     }
5185
5186   // Add a DT_FLAGS entry if necessary.
5187   unsigned int flags = 0;
5188   if (have_textrel)
5189     {
5190       // Add a DT_TEXTREL for compatibility with older loaders.
5191       odyn->add_constant(elfcpp::DT_TEXTREL, 0);
5192       flags |= elfcpp::DF_TEXTREL;
5193
5194       if (parameters->options().text())
5195         gold_error(_("read-only segment has dynamic relocations"));
5196       else if (parameters->options().warn_shared_textrel()
5197                && parameters->options().shared())
5198         gold_warning(_("shared library text segment is not shareable"));
5199     }
5200   if (parameters->options().shared() && this->has_static_tls())
5201     flags |= elfcpp::DF_STATIC_TLS;
5202   if (parameters->options().origin())
5203     flags |= elfcpp::DF_ORIGIN;
5204   if (parameters->options().Bsymbolic()
5205       && !parameters->options().have_dynamic_list())
5206     {
5207       flags |= elfcpp::DF_SYMBOLIC;
5208       // Add DT_SYMBOLIC for compatibility with older loaders.
5209       odyn->add_constant(elfcpp::DT_SYMBOLIC, 0);
5210     }
5211   if (parameters->options().now())
5212     flags |= elfcpp::DF_BIND_NOW;
5213   if (flags != 0)
5214     odyn->add_constant(elfcpp::DT_FLAGS, flags);
5215
5216   flags = 0;
5217   if (parameters->options().global())
5218     flags |= elfcpp::DF_1_GLOBAL;
5219   if (parameters->options().initfirst())
5220     flags |= elfcpp::DF_1_INITFIRST;
5221   if (parameters->options().interpose())
5222     flags |= elfcpp::DF_1_INTERPOSE;
5223   if (parameters->options().loadfltr())
5224     flags |= elfcpp::DF_1_LOADFLTR;
5225   if (parameters->options().nodefaultlib())
5226     flags |= elfcpp::DF_1_NODEFLIB;
5227   if (parameters->options().nodelete())
5228     flags |= elfcpp::DF_1_NODELETE;
5229   if (parameters->options().nodlopen())
5230     flags |= elfcpp::DF_1_NOOPEN;
5231   if (parameters->options().nodump())
5232     flags |= elfcpp::DF_1_NODUMP;
5233   if (!parameters->options().shared())
5234     flags &= ~(elfcpp::DF_1_INITFIRST
5235                | elfcpp::DF_1_NODELETE
5236                | elfcpp::DF_1_NOOPEN);
5237   if (parameters->options().origin())
5238     flags |= elfcpp::DF_1_ORIGIN;
5239   if (parameters->options().now())
5240     flags |= elfcpp::DF_1_NOW;
5241   if (parameters->options().Bgroup())
5242     flags |= elfcpp::DF_1_GROUP;
5243   if (flags != 0)
5244     odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
5245 }
5246
5247 // Set the size of the _DYNAMIC symbol table to be the size of the
5248 // dynamic data.
5249
5250 void
5251 Layout::set_dynamic_symbol_size(const Symbol_table* symtab)
5252 {
5253   Output_data_dynamic* const odyn = this->dynamic_data_;
5254   if (odyn == NULL)
5255     return;
5256   odyn->finalize_data_size();
5257   if (this->dynamic_symbol_ == NULL)
5258     return;
5259   off_t data_size = odyn->data_size();
5260   const int size = parameters->target().get_size();
5261   if (size == 32)
5262     symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size);
5263   else if (size == 64)
5264     symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size);
5265   else
5266     gold_unreachable();
5267 }
5268
5269 // The mapping of input section name prefixes to output section names.
5270 // In some cases one prefix is itself a prefix of another prefix; in
5271 // such a case the longer prefix must come first.  These prefixes are
5272 // based on the GNU linker default ELF linker script.
5273
5274 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
5275 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
5276 const Layout::Section_name_mapping Layout::section_name_mapping[] =
5277 {
5278   MAPPING_INIT(".text.", ".text"),
5279   MAPPING_INIT(".rodata.", ".rodata"),
5280   MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
5281   MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
5282   MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
5283   MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
5284   MAPPING_INIT(".data.", ".data"),
5285   MAPPING_INIT(".bss.", ".bss"),
5286   MAPPING_INIT(".tdata.", ".tdata"),
5287   MAPPING_INIT(".tbss.", ".tbss"),
5288   MAPPING_INIT(".init_array.", ".init_array"),
5289   MAPPING_INIT(".fini_array.", ".fini_array"),
5290   MAPPING_INIT(".sdata.", ".sdata"),
5291   MAPPING_INIT(".sbss.", ".sbss"),
5292   // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
5293   // differently depending on whether it is creating a shared library.
5294   MAPPING_INIT(".sdata2.", ".sdata"),
5295   MAPPING_INIT(".sbss2.", ".sbss"),
5296   MAPPING_INIT(".lrodata.", ".lrodata"),
5297   MAPPING_INIT(".ldata.", ".ldata"),
5298   MAPPING_INIT(".lbss.", ".lbss"),
5299   MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
5300   MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
5301   MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
5302   MAPPING_INIT(".gnu.linkonce.t.", ".text"),
5303   MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
5304   MAPPING_INIT(".gnu.linkonce.d.", ".data"),
5305   MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
5306   MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
5307   MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
5308   MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
5309   MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
5310   MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
5311   MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
5312   MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
5313   MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
5314   MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
5315   MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
5316   MAPPING_INIT(".ARM.extab", ".ARM.extab"),
5317   MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
5318   MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
5319   MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
5320 };
5321
5322 // Mapping for ".text" section prefixes with -z,keep-text-section-prefix.
5323 const Layout::Section_name_mapping Layout::text_section_name_mapping[] =
5324 {
5325   MAPPING_INIT(".text.hot.", ".text.hot"),
5326   MAPPING_INIT_EXACT(".text.hot", ".text.hot"),
5327   MAPPING_INIT(".text.unlikely.", ".text.unlikely"),
5328   MAPPING_INIT_EXACT(".text.unlikely", ".text.unlikely"),
5329   MAPPING_INIT(".text.startup.", ".text.startup"),
5330   MAPPING_INIT_EXACT(".text.startup", ".text.startup"),
5331   MAPPING_INIT(".text.exit.", ".text.exit"),
5332   MAPPING_INIT_EXACT(".text.exit", ".text.exit"),
5333   MAPPING_INIT(".text.", ".text"),
5334 };
5335 #undef MAPPING_INIT
5336 #undef MAPPING_INIT_EXACT
5337
5338 const int Layout::section_name_mapping_count =
5339   (sizeof(Layout::section_name_mapping)
5340    / sizeof(Layout::section_name_mapping[0]));
5341
5342 const int Layout::text_section_name_mapping_count =
5343   (sizeof(Layout::text_section_name_mapping)
5344    / sizeof(Layout::text_section_name_mapping[0]));
5345
5346 // Find section name NAME in PSNM and return the mapped name if found
5347 // with the length set in PLEN.
5348 const char *
5349 Layout::match_section_name(const Layout::Section_name_mapping* psnm,
5350                            const int count,
5351                            const char* name, size_t* plen)
5352 {
5353   for (int i = 0; i < count; ++i, ++psnm)
5354     {
5355       if (psnm->fromlen > 0)
5356         {
5357           if (strncmp(name, psnm->from, psnm->fromlen) == 0)
5358             {
5359               *plen = psnm->tolen;
5360               return psnm->to;
5361             }
5362         }
5363       else
5364         {
5365           if (strcmp(name, psnm->from) == 0)
5366             {
5367               *plen = psnm->tolen;
5368               return psnm->to;
5369             }
5370         }
5371     }
5372   return NULL;
5373 }
5374
5375 // Choose the output section name to use given an input section name.
5376 // Set *PLEN to the length of the name.  *PLEN is initialized to the
5377 // length of NAME.
5378
5379 const char*
5380 Layout::output_section_name(const Relobj* relobj, const char* name,
5381                             size_t* plen)
5382 {
5383   // gcc 4.3 generates the following sorts of section names when it
5384   // needs a section name specific to a function:
5385   //   .text.FN
5386   //   .rodata.FN
5387   //   .sdata2.FN
5388   //   .data.FN
5389   //   .data.rel.FN
5390   //   .data.rel.local.FN
5391   //   .data.rel.ro.FN
5392   //   .data.rel.ro.local.FN
5393   //   .sdata.FN
5394   //   .bss.FN
5395   //   .sbss.FN
5396   //   .tdata.FN
5397   //   .tbss.FN
5398
5399   // The GNU linker maps all of those to the part before the .FN,
5400   // except that .data.rel.local.FN is mapped to .data, and
5401   // .data.rel.ro.local.FN is mapped to .data.rel.ro.  The sections
5402   // beginning with .data.rel.ro.local are grouped together.
5403
5404   // For an anonymous namespace, the string FN can contain a '.'.
5405
5406   // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
5407   // GNU linker maps to .rodata.
5408
5409   // The .data.rel.ro sections are used with -z relro.  The sections
5410   // are recognized by name.  We use the same names that the GNU
5411   // linker does for these sections.
5412
5413   // It is hard to handle this in a principled way, so we don't even
5414   // try.  We use a table of mappings.  If the input section name is
5415   // not found in the table, we simply use it as the output section
5416   // name.
5417
5418   if (parameters->options().keep_text_section_prefix()
5419       && is_prefix_of(".text", name))
5420     {
5421       const char* match = match_section_name(text_section_name_mapping,
5422                                              text_section_name_mapping_count,
5423                                              name, plen);
5424       if (match != NULL)
5425         return match;
5426     }
5427
5428   const char* match = match_section_name(section_name_mapping,
5429                                          section_name_mapping_count, name, plen);
5430   if (match != NULL)
5431     return match;
5432
5433   // As an additional complication, .ctors sections are output in
5434   // either .ctors or .init_array sections, and .dtors sections are
5435   // output in either .dtors or .fini_array sections.
5436   if (is_prefix_of(".ctors.", name) || is_prefix_of(".dtors.", name))
5437     {
5438       if (parameters->options().ctors_in_init_array())
5439         {
5440           *plen = 11;
5441           return name[1] == 'c' ? ".init_array" : ".fini_array";
5442         }
5443       else
5444         {
5445           *plen = 6;
5446           return name[1] == 'c' ? ".ctors" : ".dtors";
5447         }
5448     }
5449   if (parameters->options().ctors_in_init_array()
5450       && (strcmp(name, ".ctors") == 0 || strcmp(name, ".dtors") == 0))
5451     {
5452       // To make .init_array/.fini_array work with gcc we must exclude
5453       // .ctors and .dtors sections from the crtbegin and crtend
5454       // files.
5455       if (relobj == NULL
5456           || (!Layout::match_file_name(relobj, "crtbegin")
5457               && !Layout::match_file_name(relobj, "crtend")))
5458         {
5459           *plen = 11;
5460           return name[1] == 'c' ? ".init_array" : ".fini_array";
5461         }
5462     }
5463
5464   return name;
5465 }
5466
5467 // Return true if RELOBJ is an input file whose base name matches
5468 // FILE_NAME.  The base name must have an extension of ".o", and must
5469 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o".  This is
5470 // to match crtbegin.o as well as crtbeginS.o without getting confused
5471 // by other possibilities.  Overall matching the file name this way is
5472 // a dreadful hack, but the GNU linker does it in order to better
5473 // support gcc, and we need to be compatible.
5474
5475 bool
5476 Layout::match_file_name(const Relobj* relobj, const char* match)
5477 {
5478   const std::string& file_name(relobj->name());
5479   const char* base_name = lbasename(file_name.c_str());
5480   size_t match_len = strlen(match);
5481   if (strncmp(base_name, match, match_len) != 0)
5482     return false;
5483   size_t base_len = strlen(base_name);
5484   if (base_len != match_len + 2 && base_len != match_len + 3)
5485     return false;
5486   return memcmp(base_name + base_len - 2, ".o", 2) == 0;
5487 }
5488
5489 // Check if a comdat group or .gnu.linkonce section with the given
5490 // NAME is selected for the link.  If there is already a section,
5491 // *KEPT_SECTION is set to point to the existing section and the
5492 // function returns false.  Otherwise, OBJECT, SHNDX, IS_COMDAT, and
5493 // IS_GROUP_NAME are recorded for this NAME in the layout object,
5494 // *KEPT_SECTION is set to the internal copy and the function returns
5495 // true.
5496
5497 bool
5498 Layout::find_or_add_kept_section(const std::string& name,
5499                                  Relobj* object,
5500                                  unsigned int shndx,
5501                                  bool is_comdat,
5502                                  bool is_group_name,
5503                                  Kept_section** kept_section)
5504 {
5505   // It's normal to see a couple of entries here, for the x86 thunk
5506   // sections.  If we see more than a few, we're linking a C++
5507   // program, and we resize to get more space to minimize rehashing.
5508   if (this->signatures_.size() > 4
5509       && !this->resized_signatures_)
5510     {
5511       reserve_unordered_map(&this->signatures_,
5512                             this->number_of_input_files_ * 64);
5513       this->resized_signatures_ = true;
5514     }
5515
5516   Kept_section candidate;
5517   std::pair<Signatures::iterator, bool> ins =
5518     this->signatures_.insert(std::make_pair(name, candidate));
5519
5520   if (kept_section != NULL)
5521     *kept_section = &ins.first->second;
5522   if (ins.second)
5523     {
5524       // This is the first time we've seen this signature.
5525       ins.first->second.set_object(object);
5526       ins.first->second.set_shndx(shndx);
5527       if (is_comdat)
5528         ins.first->second.set_is_comdat();
5529       if (is_group_name)
5530         ins.first->second.set_is_group_name();
5531       return true;
5532     }
5533
5534   // We have already seen this signature.
5535
5536   if (ins.first->second.is_group_name())
5537     {
5538       // We've already seen a real section group with this signature.
5539       // If the kept group is from a plugin object, and we're in the
5540       // replacement phase, accept the new one as a replacement.
5541       if (ins.first->second.object() == NULL
5542           && parameters->options().plugins()->in_replacement_phase())
5543         {
5544           ins.first->second.set_object(object);
5545           ins.first->second.set_shndx(shndx);
5546           return true;
5547         }
5548       return false;
5549     }
5550   else if (is_group_name)
5551     {
5552       // This is a real section group, and we've already seen a
5553       // linkonce section with this signature.  Record that we've seen
5554       // a section group, and don't include this section group.
5555       ins.first->second.set_is_group_name();
5556       return false;
5557     }
5558   else
5559     {
5560       // We've already seen a linkonce section and this is a linkonce
5561       // section.  These don't block each other--this may be the same
5562       // symbol name with different section types.
5563       return true;
5564     }
5565 }
5566
5567 // Store the allocated sections into the section list.
5568
5569 void
5570 Layout::get_allocated_sections(Section_list* section_list) const
5571 {
5572   for (Section_list::const_iterator p = this->section_list_.begin();
5573        p != this->section_list_.end();
5574        ++p)
5575     if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
5576       section_list->push_back(*p);
5577 }
5578
5579 // Store the executable sections into the section list.
5580
5581 void
5582 Layout::get_executable_sections(Section_list* section_list) const
5583 {
5584   for (Section_list::const_iterator p = this->section_list_.begin();
5585        p != this->section_list_.end();
5586        ++p)
5587     if (((*p)->flags() & (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR))
5588         == (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR))
5589       section_list->push_back(*p);
5590 }
5591
5592 // Create an output segment.
5593
5594 Output_segment*
5595 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
5596 {
5597   gold_assert(!parameters->options().relocatable());
5598   Output_segment* oseg = new Output_segment(type, flags);
5599   this->segment_list_.push_back(oseg);
5600
5601   if (type == elfcpp::PT_TLS)
5602     this->tls_segment_ = oseg;
5603   else if (type == elfcpp::PT_GNU_RELRO)
5604     this->relro_segment_ = oseg;
5605   else if (type == elfcpp::PT_INTERP)
5606     this->interp_segment_ = oseg;
5607
5608   return oseg;
5609 }
5610
5611 // Return the file offset of the normal symbol table.
5612
5613 off_t
5614 Layout::symtab_section_offset() const
5615 {
5616   if (this->symtab_section_ != NULL)
5617     return this->symtab_section_->offset();
5618   return 0;
5619 }
5620
5621 // Return the section index of the normal symbol table.  It may have
5622 // been stripped by the -s/--strip-all option.
5623
5624 unsigned int
5625 Layout::symtab_section_shndx() const
5626 {
5627   if (this->symtab_section_ != NULL)
5628     return this->symtab_section_->out_shndx();
5629   return 0;
5630 }
5631
5632 // Write out the Output_sections.  Most won't have anything to write,
5633 // since most of the data will come from input sections which are
5634 // handled elsewhere.  But some Output_sections do have Output_data.
5635
5636 void
5637 Layout::write_output_sections(Output_file* of) const
5638 {
5639   for (Section_list::const_iterator p = this->section_list_.begin();
5640        p != this->section_list_.end();
5641        ++p)
5642     {
5643       if (!(*p)->after_input_sections())
5644         (*p)->write(of);
5645     }
5646 }
5647
5648 // Write out data not associated with a section or the symbol table.
5649
5650 void
5651 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
5652 {
5653   if (!parameters->options().strip_all())
5654     {
5655       const Output_section* symtab_section = this->symtab_section_;
5656       for (Section_list::const_iterator p = this->section_list_.begin();
5657            p != this->section_list_.end();
5658            ++p)
5659         {
5660           if ((*p)->needs_symtab_index())
5661             {
5662               gold_assert(symtab_section != NULL);
5663               unsigned int index = (*p)->symtab_index();
5664               gold_assert(index > 0 && index != -1U);
5665               off_t off = (symtab_section->offset()
5666                            + index * symtab_section->entsize());
5667               symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
5668             }
5669         }
5670     }
5671
5672   const Output_section* dynsym_section = this->dynsym_section_;
5673   for (Section_list::const_iterator p = this->section_list_.begin();
5674        p != this->section_list_.end();
5675        ++p)
5676     {
5677       if ((*p)->needs_dynsym_index())
5678         {
5679           gold_assert(dynsym_section != NULL);
5680           unsigned int index = (*p)->dynsym_index();
5681           gold_assert(index > 0 && index != -1U);
5682           off_t off = (dynsym_section->offset()
5683                        + index * dynsym_section->entsize());
5684           symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
5685         }
5686     }
5687
5688   // Write out the Output_data which are not in an Output_section.
5689   for (Data_list::const_iterator p = this->special_output_list_.begin();
5690        p != this->special_output_list_.end();
5691        ++p)
5692     (*p)->write(of);
5693
5694   // Write out the Output_data which are not in an Output_section
5695   // and are regenerated in each iteration of relaxation.
5696   for (Data_list::const_iterator p = this->relax_output_list_.begin();
5697        p != this->relax_output_list_.end();
5698        ++p)
5699     (*p)->write(of);
5700 }
5701
5702 // Write out the Output_sections which can only be written after the
5703 // input sections are complete.
5704
5705 void
5706 Layout::write_sections_after_input_sections(Output_file* of)
5707 {
5708   // Determine the final section offsets, and thus the final output
5709   // file size.  Note we finalize the .shstrab last, to allow the
5710   // after_input_section sections to modify their section-names before
5711   // writing.
5712   if (this->any_postprocessing_sections_)
5713     {
5714       off_t off = this->output_file_size_;
5715       off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
5716
5717       // Now that we've finalized the names, we can finalize the shstrab.
5718       off =
5719         this->set_section_offsets(off,
5720                                   STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
5721
5722       if (off > this->output_file_size_)
5723         {
5724           of->resize(off);
5725           this->output_file_size_ = off;
5726         }
5727     }
5728
5729   for (Section_list::const_iterator p = this->section_list_.begin();
5730        p != this->section_list_.end();
5731        ++p)
5732     {
5733       if ((*p)->after_input_sections())
5734         (*p)->write(of);
5735     }
5736
5737   this->section_headers_->write(of);
5738 }
5739
5740 // If a tree-style build ID was requested, the parallel part of that computation
5741 // is already done, and the final hash-of-hashes is computed here.  For other
5742 // types of build IDs, all the work is done here.
5743
5744 void
5745 Layout::write_build_id(Output_file* of, unsigned char* array_of_hashes,
5746                        size_t size_of_hashes) const
5747 {
5748   if (this->build_id_note_ == NULL)
5749     return;
5750
5751   unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
5752                                           this->build_id_note_->data_size());
5753
5754   if (array_of_hashes == NULL)
5755     {
5756       const size_t output_file_size = this->output_file_size();
5757       const unsigned char* iv = of->get_input_view(0, output_file_size);
5758       const char* style = parameters->options().build_id();
5759
5760       // If we get here with style == "tree" then the output must be
5761       // too small for chunking, and we use SHA-1 in that case.
5762       if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0))
5763         sha1_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov);
5764       else if (strcmp(style, "md5") == 0)
5765         md5_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov);
5766       else
5767         gold_unreachable();
5768
5769       of->free_input_view(0, output_file_size, iv);
5770     }
5771   else
5772     {
5773       // Non-overlapping substrings of the output file have been hashed.
5774       // Compute SHA-1 hash of the hashes.
5775       sha1_buffer(reinterpret_cast<const char*>(array_of_hashes),
5776                   size_of_hashes, ov);
5777       delete[] array_of_hashes;
5778     }
5779
5780   of->write_output_view(this->build_id_note_->offset(),
5781                         this->build_id_note_->data_size(),
5782                         ov);
5783 }
5784
5785 // Write out a binary file.  This is called after the link is
5786 // complete.  IN is the temporary output file we used to generate the
5787 // ELF code.  We simply walk through the segments, read them from
5788 // their file offset in IN, and write them to their load address in
5789 // the output file.  FIXME: with a bit more work, we could support
5790 // S-records and/or Intel hex format here.
5791
5792 void
5793 Layout::write_binary(Output_file* in) const
5794 {
5795   gold_assert(parameters->options().oformat_enum()
5796               == General_options::OBJECT_FORMAT_BINARY);
5797
5798   // Get the size of the binary file.
5799   uint64_t max_load_address = 0;
5800   for (Segment_list::const_iterator p = this->segment_list_.begin();
5801        p != this->segment_list_.end();
5802        ++p)
5803     {
5804       if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
5805         {
5806           uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
5807           if (max_paddr > max_load_address)
5808             max_load_address = max_paddr;
5809         }
5810     }
5811
5812   Output_file out(parameters->options().output_file_name());
5813   out.open(max_load_address);
5814
5815   for (Segment_list::const_iterator p = this->segment_list_.begin();
5816        p != this->segment_list_.end();
5817        ++p)
5818     {
5819       if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
5820         {
5821           const unsigned char* vin = in->get_input_view((*p)->offset(),
5822                                                         (*p)->filesz());
5823           unsigned char* vout = out.get_output_view((*p)->paddr(),
5824                                                     (*p)->filesz());
5825           memcpy(vout, vin, (*p)->filesz());
5826           out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
5827           in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
5828         }
5829     }
5830
5831   out.close();
5832 }
5833
5834 // Print the output sections to the map file.
5835
5836 void
5837 Layout::print_to_mapfile(Mapfile* mapfile) const
5838 {
5839   for (Segment_list::const_iterator p = this->segment_list_.begin();
5840        p != this->segment_list_.end();
5841        ++p)
5842     (*p)->print_sections_to_mapfile(mapfile);
5843   for (Section_list::const_iterator p = this->unattached_section_list_.begin();
5844        p != this->unattached_section_list_.end();
5845        ++p)
5846     (*p)->print_to_mapfile(mapfile);
5847 }
5848
5849 // Print statistical information to stderr.  This is used for --stats.
5850
5851 void
5852 Layout::print_stats() const
5853 {
5854   this->namepool_.print_stats("section name pool");
5855   this->sympool_.print_stats("output symbol name pool");
5856   this->dynpool_.print_stats("dynamic name pool");
5857
5858   for (Section_list::const_iterator p = this->section_list_.begin();
5859        p != this->section_list_.end();
5860        ++p)
5861     (*p)->print_merge_stats();
5862 }
5863
5864 // Write_sections_task methods.
5865
5866 // We can always run this task.
5867
5868 Task_token*
5869 Write_sections_task::is_runnable()
5870 {
5871   return NULL;
5872 }
5873
5874 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5875 // when finished.
5876
5877 void
5878 Write_sections_task::locks(Task_locker* tl)
5879 {
5880   tl->add(this, this->output_sections_blocker_);
5881   if (this->input_sections_blocker_ != NULL)
5882     tl->add(this, this->input_sections_blocker_);
5883   tl->add(this, this->final_blocker_);
5884 }
5885
5886 // Run the task--write out the data.
5887
5888 void
5889 Write_sections_task::run(Workqueue*)
5890 {
5891   this->layout_->write_output_sections(this->of_);
5892 }
5893
5894 // Write_data_task methods.
5895
5896 // We can always run this task.
5897
5898 Task_token*
5899 Write_data_task::is_runnable()
5900 {
5901   return NULL;
5902 }
5903
5904 // We need to unlock FINAL_BLOCKER when finished.
5905
5906 void
5907 Write_data_task::locks(Task_locker* tl)
5908 {
5909   tl->add(this, this->final_blocker_);
5910 }
5911
5912 // Run the task--write out the data.
5913
5914 void
5915 Write_data_task::run(Workqueue*)
5916 {
5917   this->layout_->write_data(this->symtab_, this->of_);
5918 }
5919
5920 // Write_symbols_task methods.
5921
5922 // We can always run this task.
5923
5924 Task_token*
5925 Write_symbols_task::is_runnable()
5926 {
5927   return NULL;
5928 }
5929
5930 // We need to unlock FINAL_BLOCKER when finished.
5931
5932 void
5933 Write_symbols_task::locks(Task_locker* tl)
5934 {
5935   tl->add(this, this->final_blocker_);
5936 }
5937
5938 // Run the task--write out the symbols.
5939
5940 void
5941 Write_symbols_task::run(Workqueue*)
5942 {
5943   this->symtab_->write_globals(this->sympool_, this->dynpool_,
5944                                this->layout_->symtab_xindex(),
5945                                this->layout_->dynsym_xindex(), this->of_);
5946 }
5947
5948 // Write_after_input_sections_task methods.
5949
5950 // We can only run this task after the input sections have completed.
5951
5952 Task_token*
5953 Write_after_input_sections_task::is_runnable()
5954 {
5955   if (this->input_sections_blocker_->is_blocked())
5956     return this->input_sections_blocker_;
5957   return NULL;
5958 }
5959
5960 // We need to unlock FINAL_BLOCKER when finished.
5961
5962 void
5963 Write_after_input_sections_task::locks(Task_locker* tl)
5964 {
5965   tl->add(this, this->final_blocker_);
5966 }
5967
5968 // Run the task.
5969
5970 void
5971 Write_after_input_sections_task::run(Workqueue*)
5972 {
5973   this->layout_->write_sections_after_input_sections(this->of_);
5974 }
5975
5976 // Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes,
5977 // or as a "tree" where each chunk of the string is hashed and then those
5978 // hashes are put into a (much smaller) string which is hashed with sha1.
5979 // We compute a checksum over the entire file because that is simplest.
5980
5981 void
5982 Build_id_task_runner::run(Workqueue* workqueue, const Task*)
5983 {
5984   Task_token* post_hash_tasks_blocker = new Task_token(true);
5985   const Layout* layout = this->layout_;
5986   Output_file* of = this->of_;
5987   const size_t filesize = (layout->output_file_size() <= 0 ? 0
5988                            : static_cast<size_t>(layout->output_file_size()));
5989   unsigned char* array_of_hashes = NULL;
5990   size_t size_of_hashes = 0;
5991
5992   if (strcmp(this->options_->build_id(), "tree") == 0
5993       && this->options_->build_id_chunk_size_for_treehash() > 0
5994       && filesize > 0
5995       && (filesize >= this->options_->build_id_min_file_size_for_treehash()))
5996     {
5997       static const size_t MD5_OUTPUT_SIZE_IN_BYTES = 16;
5998       const size_t chunk_size =
5999           this->options_->build_id_chunk_size_for_treehash();
6000       const size_t num_hashes = ((filesize - 1) / chunk_size) + 1;
6001       post_hash_tasks_blocker->add_blockers(num_hashes);
6002       size_of_hashes = num_hashes * MD5_OUTPUT_SIZE_IN_BYTES;
6003       array_of_hashes = new unsigned char[size_of_hashes];
6004       unsigned char *dst = array_of_hashes;
6005       for (size_t i = 0, src_offset = 0; i < num_hashes;
6006            i++, dst += MD5_OUTPUT_SIZE_IN_BYTES, src_offset += chunk_size)
6007         {
6008           size_t size = std::min(chunk_size, filesize - src_offset);
6009           workqueue->queue(new Hash_task(of,
6010                                          src_offset,
6011                                          size,
6012                                          dst,
6013                                          post_hash_tasks_blocker));
6014         }
6015     }
6016
6017   // Queue the final task to write the build id and close the output file.
6018   workqueue->queue(new Task_function(new Close_task_runner(this->options_,
6019                                                            layout,
6020                                                            of,
6021                                                            array_of_hashes,
6022                                                            size_of_hashes),
6023                                      post_hash_tasks_blocker,
6024                                      "Task_function Close_task_runner"));
6025 }
6026
6027 // Close_task_runner methods.
6028
6029 // Finish up the build ID computation, if necessary, and write a binary file,
6030 // if necessary.  Then close the output file.
6031
6032 void
6033 Close_task_runner::run(Workqueue*, const Task*)
6034 {
6035   // At this point the multi-threaded part of the build ID computation,
6036   // if any, is done.  See Build_id_task_runner.
6037   this->layout_->write_build_id(this->of_, this->array_of_hashes_,
6038                                 this->size_of_hashes_);
6039
6040   // If we've been asked to create a binary file, we do so here.
6041   if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
6042     this->layout_->write_binary(this->of_);
6043
6044   this->of_->close();
6045 }
6046
6047 // Instantiate the templates we need.  We could use the configure
6048 // script to restrict this to only the ones for implemented targets.
6049
6050 #ifdef HAVE_TARGET_32_LITTLE
6051 template
6052 Output_section*
6053 Layout::init_fixed_output_section<32, false>(
6054     const char* name,
6055     elfcpp::Shdr<32, false>& shdr);
6056 #endif
6057
6058 #ifdef HAVE_TARGET_32_BIG
6059 template
6060 Output_section*
6061 Layout::init_fixed_output_section<32, true>(
6062     const char* name,
6063     elfcpp::Shdr<32, true>& shdr);
6064 #endif
6065
6066 #ifdef HAVE_TARGET_64_LITTLE
6067 template
6068 Output_section*
6069 Layout::init_fixed_output_section<64, false>(
6070     const char* name,
6071     elfcpp::Shdr<64, false>& shdr);
6072 #endif
6073
6074 #ifdef HAVE_TARGET_64_BIG
6075 template
6076 Output_section*
6077 Layout::init_fixed_output_section<64, true>(
6078     const char* name,
6079     elfcpp::Shdr<64, true>& shdr);
6080 #endif
6081
6082 #ifdef HAVE_TARGET_32_LITTLE
6083 template
6084 Output_section*
6085 Layout::layout<32, false>(Sized_relobj_file<32, false>* object,
6086                           unsigned int shndx,
6087                           const char* name,
6088                           const elfcpp::Shdr<32, false>& shdr,
6089                           unsigned int, unsigned int, unsigned int, off_t*);
6090 #endif
6091
6092 #ifdef HAVE_TARGET_32_BIG
6093 template
6094 Output_section*
6095 Layout::layout<32, true>(Sized_relobj_file<32, true>* object,
6096                          unsigned int shndx,
6097                          const char* name,
6098                          const elfcpp::Shdr<32, true>& shdr,
6099                          unsigned int, unsigned int, unsigned int, off_t*);
6100 #endif
6101
6102 #ifdef HAVE_TARGET_64_LITTLE
6103 template
6104 Output_section*
6105 Layout::layout<64, false>(Sized_relobj_file<64, false>* object,
6106                           unsigned int shndx,
6107                           const char* name,
6108                           const elfcpp::Shdr<64, false>& shdr,
6109                           unsigned int, unsigned int, unsigned int, off_t*);
6110 #endif
6111
6112 #ifdef HAVE_TARGET_64_BIG
6113 template
6114 Output_section*
6115 Layout::layout<64, true>(Sized_relobj_file<64, true>* object,
6116                          unsigned int shndx,
6117                          const char* name,
6118                          const elfcpp::Shdr<64, true>& shdr,
6119                          unsigned int, unsigned int, unsigned int, off_t*);
6120 #endif
6121
6122 #ifdef HAVE_TARGET_32_LITTLE
6123 template
6124 Output_section*
6125 Layout::layout_reloc<32, false>(Sized_relobj_file<32, false>* object,
6126                                 unsigned int reloc_shndx,
6127                                 const elfcpp::Shdr<32, false>& shdr,
6128                                 Output_section* data_section,
6129                                 Relocatable_relocs* rr);
6130 #endif
6131
6132 #ifdef HAVE_TARGET_32_BIG
6133 template
6134 Output_section*
6135 Layout::layout_reloc<32, true>(Sized_relobj_file<32, true>* object,
6136                                unsigned int reloc_shndx,
6137                                const elfcpp::Shdr<32, true>& shdr,
6138                                Output_section* data_section,
6139                                Relocatable_relocs* rr);
6140 #endif
6141
6142 #ifdef HAVE_TARGET_64_LITTLE
6143 template
6144 Output_section*
6145 Layout::layout_reloc<64, false>(Sized_relobj_file<64, false>* object,
6146                                 unsigned int reloc_shndx,
6147                                 const elfcpp::Shdr<64, false>& shdr,
6148                                 Output_section* data_section,
6149                                 Relocatable_relocs* rr);
6150 #endif
6151
6152 #ifdef HAVE_TARGET_64_BIG
6153 template
6154 Output_section*
6155 Layout::layout_reloc<64, true>(Sized_relobj_file<64, true>* object,
6156                                unsigned int reloc_shndx,
6157                                const elfcpp::Shdr<64, true>& shdr,
6158                                Output_section* data_section,
6159                                Relocatable_relocs* rr);
6160 #endif
6161
6162 #ifdef HAVE_TARGET_32_LITTLE
6163 template
6164 void
6165 Layout::layout_group<32, false>(Symbol_table* symtab,
6166                                 Sized_relobj_file<32, false>* object,
6167                                 unsigned int,
6168                                 const char* group_section_name,
6169                                 const char* signature,
6170                                 const elfcpp::Shdr<32, false>& shdr,
6171                                 elfcpp::Elf_Word flags,
6172                                 std::vector<unsigned int>* shndxes);
6173 #endif
6174
6175 #ifdef HAVE_TARGET_32_BIG
6176 template
6177 void
6178 Layout::layout_group<32, true>(Symbol_table* symtab,
6179                                Sized_relobj_file<32, true>* object,
6180                                unsigned int,
6181                                const char* group_section_name,
6182                                const char* signature,
6183                                const elfcpp::Shdr<32, true>& shdr,
6184                                elfcpp::Elf_Word flags,
6185                                std::vector<unsigned int>* shndxes);
6186 #endif
6187
6188 #ifdef HAVE_TARGET_64_LITTLE
6189 template
6190 void
6191 Layout::layout_group<64, false>(Symbol_table* symtab,
6192                                 Sized_relobj_file<64, false>* object,
6193                                 unsigned int,
6194                                 const char* group_section_name,
6195                                 const char* signature,
6196                                 const elfcpp::Shdr<64, false>& shdr,
6197                                 elfcpp::Elf_Word flags,
6198                                 std::vector<unsigned int>* shndxes);
6199 #endif
6200
6201 #ifdef HAVE_TARGET_64_BIG
6202 template
6203 void
6204 Layout::layout_group<64, true>(Symbol_table* symtab,
6205                                Sized_relobj_file<64, true>* object,
6206                                unsigned int,
6207                                const char* group_section_name,
6208                                const char* signature,
6209                                const elfcpp::Shdr<64, true>& shdr,
6210                                elfcpp::Elf_Word flags,
6211                                std::vector<unsigned int>* shndxes);
6212 #endif
6213
6214 #ifdef HAVE_TARGET_32_LITTLE
6215 template
6216 Output_section*
6217 Layout::layout_eh_frame<32, false>(Sized_relobj_file<32, false>* object,
6218                                    const unsigned char* symbols,
6219                                    off_t symbols_size,
6220                                    const unsigned char* symbol_names,
6221                                    off_t symbol_names_size,
6222                                    unsigned int shndx,
6223                                    const elfcpp::Shdr<32, false>& shdr,
6224                                    unsigned int reloc_shndx,
6225                                    unsigned int reloc_type,
6226                                    off_t* off);
6227 #endif
6228
6229 #ifdef HAVE_TARGET_32_BIG
6230 template
6231 Output_section*
6232 Layout::layout_eh_frame<32, true>(Sized_relobj_file<32, true>* object,
6233                                   const unsigned char* symbols,
6234                                   off_t symbols_size,
6235                                   const unsigned char* symbol_names,
6236                                   off_t symbol_names_size,
6237                                   unsigned int shndx,
6238                                   const elfcpp::Shdr<32, true>& shdr,
6239                                   unsigned int reloc_shndx,
6240                                   unsigned int reloc_type,
6241                                   off_t* off);
6242 #endif
6243
6244 #ifdef HAVE_TARGET_64_LITTLE
6245 template
6246 Output_section*
6247 Layout::layout_eh_frame<64, false>(Sized_relobj_file<64, false>* object,
6248                                    const unsigned char* symbols,
6249                                    off_t symbols_size,
6250                                    const unsigned char* symbol_names,
6251                                    off_t symbol_names_size,
6252                                    unsigned int shndx,
6253                                    const elfcpp::Shdr<64, false>& shdr,
6254                                    unsigned int reloc_shndx,
6255                                    unsigned int reloc_type,
6256                                    off_t* off);
6257 #endif
6258
6259 #ifdef HAVE_TARGET_64_BIG
6260 template
6261 Output_section*
6262 Layout::layout_eh_frame<64, true>(Sized_relobj_file<64, true>* object,
6263                                   const unsigned char* symbols,
6264                                   off_t symbols_size,
6265                                   const unsigned char* symbol_names,
6266                                   off_t symbol_names_size,
6267                                   unsigned int shndx,
6268                                   const elfcpp::Shdr<64, true>& shdr,
6269                                   unsigned int reloc_shndx,
6270                                   unsigned int reloc_type,
6271                                   off_t* off);
6272 #endif
6273
6274 #ifdef HAVE_TARGET_32_LITTLE
6275 template
6276 void
6277 Layout::add_to_gdb_index(bool is_type_unit,
6278                          Sized_relobj<32, false>* object,
6279                          const unsigned char* symbols,
6280                          off_t symbols_size,
6281                          unsigned int shndx,
6282                          unsigned int reloc_shndx,
6283                          unsigned int reloc_type);
6284 #endif
6285
6286 #ifdef HAVE_TARGET_32_BIG
6287 template
6288 void
6289 Layout::add_to_gdb_index(bool is_type_unit,
6290                          Sized_relobj<32, true>* object,
6291                          const unsigned char* symbols,
6292                          off_t symbols_size,
6293                          unsigned int shndx,
6294                          unsigned int reloc_shndx,
6295                          unsigned int reloc_type);
6296 #endif
6297
6298 #ifdef HAVE_TARGET_64_LITTLE
6299 template
6300 void
6301 Layout::add_to_gdb_index(bool is_type_unit,
6302                          Sized_relobj<64, false>* object,
6303                          const unsigned char* symbols,
6304                          off_t symbols_size,
6305                          unsigned int shndx,
6306                          unsigned int reloc_shndx,
6307                          unsigned int reloc_type);
6308 #endif
6309
6310 #ifdef HAVE_TARGET_64_BIG
6311 template
6312 void
6313 Layout::add_to_gdb_index(bool is_type_unit,
6314                          Sized_relobj<64, true>* object,
6315                          const unsigned char* symbols,
6316                          off_t symbols_size,
6317                          unsigned int shndx,
6318                          unsigned int reloc_shndx,
6319                          unsigned int reloc_type);
6320 #endif
6321
6322 } // End namespace gold.