* dynobj.h (Dynobj::do_dynobj): New function.
[platform/upstream/binutils.git] / gold / layout.cc
1 // layout.cc -- lay out output file sections for gold
2
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5
6 // This file is part of gold.
7
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22
23 #include "gold.h"
24
25 #include <cerrno>
26 #include <cstring>
27 #include <algorithm>
28 #include <iostream>
29 #include <fstream>
30 #include <utility>
31 #include <fcntl.h>
32 #include <fnmatch.h>
33 #include <unistd.h>
34 #include "libiberty.h"
35 #include "md5.h"
36 #include "sha1.h"
37
38 #include "parameters.h"
39 #include "options.h"
40 #include "mapfile.h"
41 #include "script.h"
42 #include "script-sections.h"
43 #include "output.h"
44 #include "symtab.h"
45 #include "dynobj.h"
46 #include "ehframe.h"
47 #include "compressed_output.h"
48 #include "reduced_debug_output.h"
49 #include "reloc.h"
50 #include "descriptors.h"
51 #include "plugin.h"
52 #include "incremental.h"
53 #include "layout.h"
54
55 namespace gold
56 {
57
58 // Class Free_list.
59
60 // The total number of free lists used.
61 unsigned int Free_list::num_lists = 0;
62 // The total number of free list nodes used.
63 unsigned int Free_list::num_nodes = 0;
64 // The total number of calls to Free_list::remove.
65 unsigned int Free_list::num_removes = 0;
66 // The total number of nodes visited during calls to Free_list::remove.
67 unsigned int Free_list::num_remove_visits = 0;
68 // The total number of calls to Free_list::allocate.
69 unsigned int Free_list::num_allocates = 0;
70 // The total number of nodes visited during calls to Free_list::allocate.
71 unsigned int Free_list::num_allocate_visits = 0;
72
73 // Initialize the free list.  Creates a single free list node that
74 // describes the entire region of length LEN.  If EXTEND is true,
75 // allocate() is allowed to extend the region beyond its initial
76 // length.
77
78 void
79 Free_list::init(off_t len, bool extend)
80 {
81   this->list_.push_front(Free_list_node(0, len));
82   this->last_remove_ = this->list_.begin();
83   this->extend_ = extend;
84   this->length_ = len;
85   ++Free_list::num_lists;
86   ++Free_list::num_nodes;
87 }
88
89 // Remove a chunk from the free list.  Because we start with a single
90 // node that covers the entire section, and remove chunks from it one
91 // at a time, we do not need to coalesce chunks or handle cases that
92 // span more than one free node.  We expect to remove chunks from the
93 // free list in order, and we expect to have only a few chunks of free
94 // space left (corresponding to files that have changed since the last
95 // incremental link), so a simple linear list should provide sufficient
96 // performance.
97
98 void
99 Free_list::remove(off_t start, off_t end)
100 {
101   if (start == end)
102     return;
103   gold_assert(start < end);
104
105   ++Free_list::num_removes;
106
107   Iterator p = this->last_remove_;
108   if (p->start_ > start)
109     p = this->list_.begin();
110
111   for (; p != this->list_.end(); ++p)
112     {
113       ++Free_list::num_remove_visits;
114       // Find a node that wholly contains the indicated region.
115       if (p->start_ <= start && p->end_ >= end)
116         {
117           // Case 1: the indicated region spans the whole node.
118           // Add some fuzz to avoid creating tiny free chunks.
119           if (p->start_ + 3 >= start && p->end_ <= end + 3)
120             p = this->list_.erase(p);
121           // Case 2: remove a chunk from the start of the node.
122           else if (p->start_ + 3 >= start)
123             p->start_ = end;
124           // Case 3: remove a chunk from the end of the node.
125           else if (p->end_ <= end + 3)
126             p->end_ = start;
127           // Case 4: remove a chunk from the middle, and split
128           // the node into two.
129           else
130             {
131               Free_list_node newnode(p->start_, start);
132               p->start_ = end;
133               this->list_.insert(p, newnode);
134               ++Free_list::num_nodes;
135             }
136           this->last_remove_ = p;
137           return;
138         }
139     }
140
141   // Did not find a node containing the given chunk.  This could happen
142   // because a small chunk was already removed due to the fuzz.
143   gold_debug(DEBUG_INCREMENTAL,
144              "Free_list::remove(%d,%d) not found",
145              static_cast<int>(start), static_cast<int>(end));
146 }
147
148 // Allocate a chunk of size LEN from the free list.  Returns -1ULL
149 // if a sufficiently large chunk of free space is not found.
150 // We use a simple first-fit algorithm.
151
152 off_t
153 Free_list::allocate(off_t len, uint64_t align, off_t minoff)
154 {
155   gold_debug(DEBUG_INCREMENTAL,
156              "Free_list::allocate(%08lx, %d, %08lx)",
157              static_cast<long>(len), static_cast<int>(align),
158              static_cast<long>(minoff));
159   if (len == 0)
160     return align_address(minoff, align);
161
162   ++Free_list::num_allocates;
163
164   for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
165     {
166       ++Free_list::num_allocate_visits;
167       off_t start = p->start_ > minoff ? p->start_ : minoff;
168       start = align_address(start, align);
169       off_t end = start + len;
170       if (end <= p->end_)
171         {
172           if (p->start_ + 3 >= start && p->end_ <= end + 3)
173             this->list_.erase(p);
174           else if (p->start_ + 3 >= start)
175             p->start_ = end;
176           else if (p->end_ <= end + 3)
177             p->end_ = start;
178           else
179             {
180               Free_list_node newnode(p->start_, start);
181               p->start_ = end;
182               this->list_.insert(p, newnode);
183               ++Free_list::num_nodes;
184             }
185           return start;
186         }
187     }
188   return -1;
189 }
190
191 // Dump the free list (for debugging).
192 void
193 Free_list::dump()
194 {
195   gold_info("Free list:\n     start      end   length\n");
196   for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
197     gold_info("  %08lx %08lx %08lx", static_cast<long>(p->start_),
198               static_cast<long>(p->end_),
199               static_cast<long>(p->end_ - p->start_));
200 }
201
202 // Print the statistics for the free lists.
203 void
204 Free_list::print_stats()
205 {
206   fprintf(stderr, _("%s: total free lists: %u\n"),
207           program_name, Free_list::num_lists);
208   fprintf(stderr, _("%s: total free list nodes: %u\n"),
209           program_name, Free_list::num_nodes);
210   fprintf(stderr, _("%s: calls to Free_list::remove: %u\n"),
211           program_name, Free_list::num_removes);
212   fprintf(stderr, _("%s: nodes visited: %u\n"),
213           program_name, Free_list::num_remove_visits);
214   fprintf(stderr, _("%s: calls to Free_list::allocate: %u\n"),
215           program_name, Free_list::num_allocates);
216   fprintf(stderr, _("%s: nodes visited: %u\n"),
217           program_name, Free_list::num_allocate_visits);
218 }
219
220 // Layout::Relaxation_debug_check methods.
221
222 // Check that sections and special data are in reset states.
223 // We do not save states for Output_sections and special Output_data.
224 // So we check that they have not assigned any addresses or offsets.
225 // clean_up_after_relaxation simply resets their addresses and offsets.
226 void
227 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
228     const Layout::Section_list& sections,
229     const Layout::Data_list& special_outputs)
230 {
231   for(Layout::Section_list::const_iterator p = sections.begin();
232       p != sections.end();
233       ++p)
234     gold_assert((*p)->address_and_file_offset_have_reset_values());
235
236   for(Layout::Data_list::const_iterator p = special_outputs.begin();
237       p != special_outputs.end();
238       ++p)
239     gold_assert((*p)->address_and_file_offset_have_reset_values());
240 }
241   
242 // Save information of SECTIONS for checking later.
243
244 void
245 Layout::Relaxation_debug_check::read_sections(
246     const Layout::Section_list& sections)
247 {
248   for(Layout::Section_list::const_iterator p = sections.begin();
249       p != sections.end();
250       ++p)
251     {
252       Output_section* os = *p;
253       Section_info info;
254       info.output_section = os;
255       info.address = os->is_address_valid() ? os->address() : 0;
256       info.data_size = os->is_data_size_valid() ? os->data_size() : -1;
257       info.offset = os->is_offset_valid()? os->offset() : -1 ;
258       this->section_infos_.push_back(info);
259     }
260 }
261
262 // Verify SECTIONS using previously recorded information.
263
264 void
265 Layout::Relaxation_debug_check::verify_sections(
266     const Layout::Section_list& sections)
267 {
268   size_t i = 0;
269   for(Layout::Section_list::const_iterator p = sections.begin();
270       p != sections.end();
271       ++p, ++i)
272     {
273       Output_section* os = *p;
274       uint64_t address = os->is_address_valid() ? os->address() : 0;
275       off_t data_size = os->is_data_size_valid() ? os->data_size() : -1;
276       off_t offset = os->is_offset_valid()? os->offset() : -1 ;
277
278       if (i >= this->section_infos_.size())
279         {
280           gold_fatal("Section_info of %s missing.\n", os->name());
281         }
282       const Section_info& info = this->section_infos_[i];
283       if (os != info.output_section)
284         gold_fatal("Section order changed.  Expecting %s but see %s\n",
285                    info.output_section->name(), os->name());
286       if (address != info.address
287           || data_size != info.data_size
288           || offset != info.offset)
289         gold_fatal("Section %s changed.\n", os->name());
290     }
291 }
292
293 // Layout_task_runner methods.
294
295 // Lay out the sections.  This is called after all the input objects
296 // have been read.
297
298 void
299 Layout_task_runner::run(Workqueue* workqueue, const Task* task)
300 {
301   Layout* layout = this->layout_;
302   off_t file_size = layout->finalize(this->input_objects_,
303                                      this->symtab_,
304                                      this->target_,
305                                      task);
306
307   // Now we know the final size of the output file and we know where
308   // each piece of information goes.
309
310   if (this->mapfile_ != NULL)
311     {
312       this->mapfile_->print_discarded_sections(this->input_objects_);
313       layout->print_to_mapfile(this->mapfile_);
314     }
315
316   Output_file* of;
317   if (layout->incremental_base() == NULL)
318     {
319       of = new Output_file(parameters->options().output_file_name());
320       if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
321         of->set_is_temporary();
322       of->open(file_size);
323     }
324   else
325     {
326       of = layout->incremental_base()->output_file();
327
328       // Apply the incremental relocations for symbols whose values
329       // have changed.  We do this before we resize the file and start
330       // writing anything else to it, so that we can read the old
331       // incremental information from the file before (possibly)
332       // overwriting it.
333       if (parameters->incremental_update())
334         layout->incremental_base()->apply_incremental_relocs(this->symtab_,
335                                                              this->layout_,
336                                                              of);
337
338       of->resize(file_size);
339     }
340
341   // Queue up the final set of tasks.
342   gold::queue_final_tasks(this->options_, this->input_objects_,
343                           this->symtab_, layout, workqueue, of);
344 }
345
346 // Layout methods.
347
348 Layout::Layout(int number_of_input_files, Script_options* script_options)
349   : number_of_input_files_(number_of_input_files),
350     script_options_(script_options),
351     namepool_(),
352     sympool_(),
353     dynpool_(),
354     signatures_(),
355     section_name_map_(),
356     segment_list_(),
357     section_list_(),
358     unattached_section_list_(),
359     special_output_list_(),
360     section_headers_(NULL),
361     tls_segment_(NULL),
362     relro_segment_(NULL),
363     increase_relro_(0),
364     symtab_section_(NULL),
365     symtab_xindex_(NULL),
366     dynsym_section_(NULL),
367     dynsym_xindex_(NULL),
368     dynamic_section_(NULL),
369     dynamic_symbol_(NULL),
370     dynamic_data_(NULL),
371     eh_frame_section_(NULL),
372     eh_frame_data_(NULL),
373     added_eh_frame_data_(false),
374     eh_frame_hdr_section_(NULL),
375     build_id_note_(NULL),
376     debug_abbrev_(NULL),
377     debug_info_(NULL),
378     group_signatures_(),
379     output_file_size_(-1),
380     have_added_input_section_(false),
381     sections_are_attached_(false),
382     input_requires_executable_stack_(false),
383     input_with_gnu_stack_note_(false),
384     input_without_gnu_stack_note_(false),
385     has_static_tls_(false),
386     any_postprocessing_sections_(false),
387     resized_signatures_(false),
388     have_stabstr_section_(false),
389     incremental_inputs_(NULL),
390     record_output_section_data_from_script_(false),
391     script_output_section_data_list_(),
392     segment_states_(NULL),
393     relaxation_debug_check_(NULL),
394     incremental_base_(NULL),
395     free_list_()
396 {
397   // Make space for more than enough segments for a typical file.
398   // This is just for efficiency--it's OK if we wind up needing more.
399   this->segment_list_.reserve(12);
400
401   // We expect two unattached Output_data objects: the file header and
402   // the segment headers.
403   this->special_output_list_.reserve(2);
404
405   // Initialize structure needed for an incremental build.
406   if (parameters->incremental())
407     this->incremental_inputs_ = new Incremental_inputs;
408
409   // The section name pool is worth optimizing in all cases, because
410   // it is small, but there are often overlaps due to .rel sections.
411   this->namepool_.set_optimize();
412 }
413
414 // For incremental links, record the base file to be modified.
415
416 void
417 Layout::set_incremental_base(Incremental_binary* base)
418 {
419   this->incremental_base_ = base;
420   this->free_list_.init(base->output_file()->filesize(), true);
421 }
422
423 // Hash a key we use to look up an output section mapping.
424
425 size_t
426 Layout::Hash_key::operator()(const Layout::Key& k) const
427 {
428  return k.first + k.second.first + k.second.second;
429 }
430
431 // Returns whether the given section is in the list of
432 // debug-sections-used-by-some-version-of-gdb.  Currently,
433 // we've checked versions of gdb up to and including 6.7.1.
434
435 static const char* gdb_sections[] =
436 { ".debug_abbrev",
437   // ".debug_aranges",   // not used by gdb as of 6.7.1
438   ".debug_frame",
439   ".debug_info",
440   ".debug_types",
441   ".debug_line",
442   ".debug_loc",
443   ".debug_macinfo",
444   // ".debug_pubnames",  // not used by gdb as of 6.7.1
445   ".debug_ranges",
446   ".debug_str",
447 };
448
449 static const char* lines_only_debug_sections[] =
450 { ".debug_abbrev",
451   // ".debug_aranges",   // not used by gdb as of 6.7.1
452   // ".debug_frame",
453   ".debug_info",
454   // ".debug_types",
455   ".debug_line",
456   // ".debug_loc",
457   // ".debug_macinfo",
458   // ".debug_pubnames",  // not used by gdb as of 6.7.1
459   // ".debug_ranges",
460   ".debug_str",
461 };
462
463 static inline bool
464 is_gdb_debug_section(const char* str)
465 {
466   // We can do this faster: binary search or a hashtable.  But why bother?
467   for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
468     if (strcmp(str, gdb_sections[i]) == 0)
469       return true;
470   return false;
471 }
472
473 static inline bool
474 is_lines_only_debug_section(const char* str)
475 {
476   // We can do this faster: binary search or a hashtable.  But why bother?
477   for (size_t i = 0;
478        i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections);
479        ++i)
480     if (strcmp(str, lines_only_debug_sections[i]) == 0)
481       return true;
482   return false;
483 }
484
485 // Sometimes we compress sections.  This is typically done for
486 // sections that are not part of normal program execution (such as
487 // .debug_* sections), and where the readers of these sections know
488 // how to deal with compressed sections.  This routine doesn't say for
489 // certain whether we'll compress -- it depends on commandline options
490 // as well -- just whether this section is a candidate for compression.
491 // (The Output_compressed_section class decides whether to compress
492 // a given section, and picks the name of the compressed section.)
493
494 static bool
495 is_compressible_debug_section(const char* secname)
496 {
497   return (is_prefix_of(".debug", secname));
498 }
499
500 // We may see compressed debug sections in input files.  Return TRUE
501 // if this is the name of a compressed debug section.
502
503 bool
504 is_compressed_debug_section(const char* secname)
505 {
506   return (is_prefix_of(".zdebug", secname));
507 }
508
509 // Whether to include this section in the link.
510
511 template<int size, bool big_endian>
512 bool
513 Layout::include_section(Sized_relobj_file<size, big_endian>*, const char* name,
514                         const elfcpp::Shdr<size, big_endian>& shdr)
515 {
516   if (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE)
517     return false;
518
519   switch (shdr.get_sh_type())
520     {
521     case elfcpp::SHT_NULL:
522     case elfcpp::SHT_SYMTAB:
523     case elfcpp::SHT_DYNSYM:
524     case elfcpp::SHT_HASH:
525     case elfcpp::SHT_DYNAMIC:
526     case elfcpp::SHT_SYMTAB_SHNDX:
527       return false;
528
529     case elfcpp::SHT_STRTAB:
530       // Discard the sections which have special meanings in the ELF
531       // ABI.  Keep others (e.g., .stabstr).  We could also do this by
532       // checking the sh_link fields of the appropriate sections.
533       return (strcmp(name, ".dynstr") != 0
534               && strcmp(name, ".strtab") != 0
535               && strcmp(name, ".shstrtab") != 0);
536
537     case elfcpp::SHT_RELA:
538     case elfcpp::SHT_REL:
539     case elfcpp::SHT_GROUP:
540       // If we are emitting relocations these should be handled
541       // elsewhere.
542       gold_assert(!parameters->options().relocatable()
543                   && !parameters->options().emit_relocs());
544       return false;
545
546     case elfcpp::SHT_PROGBITS:
547       if (parameters->options().strip_debug()
548           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
549         {
550           if (is_debug_info_section(name))
551             return false;
552         }
553       if (parameters->options().strip_debug_non_line()
554           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
555         {
556           // Debugging sections can only be recognized by name.
557           if (is_prefix_of(".debug", name)
558               && !is_lines_only_debug_section(name))
559             return false;
560         }
561       if (parameters->options().strip_debug_gdb()
562           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
563         {
564           // Debugging sections can only be recognized by name.
565           if (is_prefix_of(".debug", name)
566               && !is_gdb_debug_section(name))
567             return false;
568         }
569       if (parameters->options().strip_lto_sections()
570           && !parameters->options().relocatable()
571           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
572         {
573           // Ignore LTO sections containing intermediate code.
574           if (is_prefix_of(".gnu.lto_", name))
575             return false;
576         }
577       // The GNU linker strips .gnu_debuglink sections, so we do too.
578       // This is a feature used to keep debugging information in
579       // separate files.
580       if (strcmp(name, ".gnu_debuglink") == 0)
581         return false;
582       return true;
583
584     default:
585       return true;
586     }
587 }
588
589 // Return an output section named NAME, or NULL if there is none.
590
591 Output_section*
592 Layout::find_output_section(const char* name) const
593 {
594   for (Section_list::const_iterator p = this->section_list_.begin();
595        p != this->section_list_.end();
596        ++p)
597     if (strcmp((*p)->name(), name) == 0)
598       return *p;
599   return NULL;
600 }
601
602 // Return an output segment of type TYPE, with segment flags SET set
603 // and segment flags CLEAR clear.  Return NULL if there is none.
604
605 Output_segment*
606 Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
607                             elfcpp::Elf_Word clear) const
608 {
609   for (Segment_list::const_iterator p = this->segment_list_.begin();
610        p != this->segment_list_.end();
611        ++p)
612     if (static_cast<elfcpp::PT>((*p)->type()) == type
613         && ((*p)->flags() & set) == set
614         && ((*p)->flags() & clear) == 0)
615       return *p;
616   return NULL;
617 }
618
619 // Return the output section to use for section NAME with type TYPE
620 // and section flags FLAGS.  NAME must be canonicalized in the string
621 // pool, and NAME_KEY is the key.  IS_INTERP is true if this is the
622 // .interp section.  IS_DYNAMIC_LINKER_SECTION is true if this section
623 // is used by the dynamic linker.  IS_RELRO is true for a relro
624 // section.  IS_LAST_RELRO is true for the last relro section.
625 // IS_FIRST_NON_RELRO is true for the first non-relro section.
626
627 Output_section*
628 Layout::get_output_section(const char* name, Stringpool::Key name_key,
629                            elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
630                            Output_section_order order, bool is_relro)
631 {
632   elfcpp::Elf_Xword lookup_flags = flags;
633
634   // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
635   // read-write with read-only sections.  Some other ELF linkers do
636   // not do this.  FIXME: Perhaps there should be an option
637   // controlling this.
638   lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
639
640   const Key key(name_key, std::make_pair(type, lookup_flags));
641   const std::pair<Key, Output_section*> v(key, NULL);
642   std::pair<Section_name_map::iterator, bool> ins(
643     this->section_name_map_.insert(v));
644
645   if (!ins.second)
646     return ins.first->second;
647   else
648     {
649       // This is the first time we've seen this name/type/flags
650       // combination.  For compatibility with the GNU linker, we
651       // combine sections with contents and zero flags with sections
652       // with non-zero flags.  This is a workaround for cases where
653       // assembler code forgets to set section flags.  FIXME: Perhaps
654       // there should be an option to control this.
655       Output_section* os = NULL;
656
657       if (type == elfcpp::SHT_PROGBITS)
658         {
659           if (flags == 0)
660             {
661               Output_section* same_name = this->find_output_section(name);
662               if (same_name != NULL
663                   && same_name->type() == elfcpp::SHT_PROGBITS
664                   && (same_name->flags() & elfcpp::SHF_TLS) == 0)
665                 os = same_name;
666             }
667           else if ((flags & elfcpp::SHF_TLS) == 0)
668             {
669               elfcpp::Elf_Xword zero_flags = 0;
670               const Key zero_key(name_key, std::make_pair(type, zero_flags));
671               Section_name_map::iterator p =
672                   this->section_name_map_.find(zero_key);
673               if (p != this->section_name_map_.end())
674                 os = p->second;
675             }
676         }
677
678       if (os == NULL)
679         os = this->make_output_section(name, type, flags, order, is_relro);
680
681       ins.first->second = os;
682       return os;
683     }
684 }
685
686 // Pick the output section to use for section NAME, in input file
687 // RELOBJ, with type TYPE and flags FLAGS.  RELOBJ may be NULL for a
688 // linker created section.  IS_INPUT_SECTION is true if we are
689 // choosing an output section for an input section found in a input
690 // file.  IS_INTERP is true if this is the .interp section.
691 // IS_DYNAMIC_LINKER_SECTION is true if this section is used by the
692 // dynamic linker.  IS_RELRO is true for a relro section.
693 // IS_LAST_RELRO is true for the last relro section.
694 // IS_FIRST_NON_RELRO is true for the first non-relro section.  This
695 // will return NULL if the input section should be discarded.
696
697 Output_section*
698 Layout::choose_output_section(const Relobj* relobj, const char* name,
699                               elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
700                               bool is_input_section, Output_section_order order,
701                               bool is_relro)
702 {
703   // We should not see any input sections after we have attached
704   // sections to segments.
705   gold_assert(!is_input_section || !this->sections_are_attached_);
706
707   // Some flags in the input section should not be automatically
708   // copied to the output section.
709   flags &= ~ (elfcpp::SHF_INFO_LINK
710               | elfcpp::SHF_GROUP
711               | elfcpp::SHF_MERGE
712               | elfcpp::SHF_STRINGS);
713
714   // We only clear the SHF_LINK_ORDER flag in for
715   // a non-relocatable link.
716   if (!parameters->options().relocatable())
717     flags &= ~elfcpp::SHF_LINK_ORDER;
718
719   if (this->script_options_->saw_sections_clause())
720     {
721       // We are using a SECTIONS clause, so the output section is
722       // chosen based only on the name.
723
724       Script_sections* ss = this->script_options_->script_sections();
725       const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
726       Output_section** output_section_slot;
727       Script_sections::Section_type script_section_type;
728       const char* orig_name = name;
729       name = ss->output_section_name(file_name, name, &output_section_slot,
730                                      &script_section_type);
731       if (name == NULL)
732         {
733           gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' "
734                                      "because it is not allowed by the "
735                                      "SECTIONS clause of the linker script"),
736                      orig_name);
737           // The SECTIONS clause says to discard this input section.
738           return NULL;
739         }
740
741       // We can only handle script section types ST_NONE and ST_NOLOAD.
742       switch (script_section_type)
743         {
744         case Script_sections::ST_NONE:
745           break;
746         case Script_sections::ST_NOLOAD:
747           flags &= elfcpp::SHF_ALLOC;
748           break;
749         default:
750           gold_unreachable();
751         }
752
753       // If this is an orphan section--one not mentioned in the linker
754       // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
755       // default processing below.
756
757       if (output_section_slot != NULL)
758         {
759           if (*output_section_slot != NULL)
760             {
761               (*output_section_slot)->update_flags_for_input_section(flags);
762               return *output_section_slot;
763             }
764
765           // We don't put sections found in the linker script into
766           // SECTION_NAME_MAP_.  That keeps us from getting confused
767           // if an orphan section is mapped to a section with the same
768           // name as one in the linker script.
769
770           name = this->namepool_.add(name, false, NULL);
771
772           Output_section* os = this->make_output_section(name, type, flags,
773                                                          order, is_relro);
774
775           os->set_found_in_sections_clause();
776
777           // Special handling for NOLOAD sections.
778           if (script_section_type == Script_sections::ST_NOLOAD)
779             {
780               os->set_is_noload();
781
782               // The constructor of Output_section sets addresses of non-ALLOC
783               // sections to 0 by default.  We don't want that for NOLOAD
784               // sections even if they have no SHF_ALLOC flag.
785               if ((os->flags() & elfcpp::SHF_ALLOC) == 0
786                   && os->is_address_valid())
787                 {
788                   gold_assert(os->address() == 0
789                               && !os->is_offset_valid()
790                               && !os->is_data_size_valid());
791                   os->reset_address_and_file_offset();
792                 }
793             }
794
795           *output_section_slot = os;
796           return os;
797         }
798     }
799
800   // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
801
802   size_t len = strlen(name);
803   char* uncompressed_name = NULL;
804
805   // Compressed debug sections should be mapped to the corresponding
806   // uncompressed section.
807   if (is_compressed_debug_section(name))
808     {
809       uncompressed_name = new char[len];
810       uncompressed_name[0] = '.';
811       gold_assert(name[0] == '.' && name[1] == 'z');
812       strncpy(&uncompressed_name[1], &name[2], len - 2);
813       uncompressed_name[len - 1] = '\0';
814       len -= 1;
815       name = uncompressed_name;
816     }
817
818   // Turn NAME from the name of the input section into the name of the
819   // output section.
820   if (is_input_section
821       && !this->script_options_->saw_sections_clause()
822       && !parameters->options().relocatable())
823     name = Layout::output_section_name(name, &len);
824
825   Stringpool::Key name_key;
826   name = this->namepool_.add_with_length(name, len, true, &name_key);
827
828   if (uncompressed_name != NULL)
829     delete[] uncompressed_name;
830
831   // Find or make the output section.  The output section is selected
832   // based on the section name, type, and flags.
833   return this->get_output_section(name, name_key, type, flags, order, is_relro);
834 }
835
836 // For incremental links, record the initial fixed layout of a section
837 // from the base file, and return a pointer to the Output_section.
838
839 template<int size, bool big_endian>
840 Output_section*
841 Layout::init_fixed_output_section(const char* name,
842                                   elfcpp::Shdr<size, big_endian>& shdr)
843 {
844   unsigned int sh_type = shdr.get_sh_type();
845
846   // We preserve the layout of PROGBITS, NOBITS, and NOTE sections.
847   // All others will be created from scratch and reallocated.
848   if (sh_type != elfcpp::SHT_PROGBITS
849       && sh_type != elfcpp::SHT_NOBITS
850       && sh_type != elfcpp::SHT_NOTE)
851     return NULL;
852
853   typename elfcpp::Elf_types<size>::Elf_Addr sh_addr = shdr.get_sh_addr();
854   typename elfcpp::Elf_types<size>::Elf_Off sh_offset = shdr.get_sh_offset();
855   typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
856   typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
857   typename elfcpp::Elf_types<size>::Elf_WXword sh_addralign =
858       shdr.get_sh_addralign();
859
860   // Make the output section.
861   Stringpool::Key name_key;
862   name = this->namepool_.add(name, true, &name_key);
863   Output_section* os = this->get_output_section(name, name_key, sh_type,
864                                                 sh_flags, ORDER_INVALID, false);
865   os->set_fixed_layout(sh_addr, sh_offset, sh_size, sh_addralign);
866   if (sh_type != elfcpp::SHT_NOBITS)
867     this->free_list_.remove(sh_offset, sh_offset + sh_size);
868   return os;
869 }
870
871 // Return the output section to use for input section SHNDX, with name
872 // NAME, with header HEADER, from object OBJECT.  RELOC_SHNDX is the
873 // index of a relocation section which applies to this section, or 0
874 // if none, or -1U if more than one.  RELOC_TYPE is the type of the
875 // relocation section if there is one.  Set *OFF to the offset of this
876 // input section without the output section.  Return NULL if the
877 // section should be discarded.  Set *OFF to -1 if the section
878 // contents should not be written directly to the output file, but
879 // will instead receive special handling.
880
881 template<int size, bool big_endian>
882 Output_section*
883 Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
884                const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
885                unsigned int reloc_shndx, unsigned int, off_t* off)
886 {
887   *off = 0;
888
889   if (!this->include_section(object, name, shdr))
890     return NULL;
891
892   Output_section* os;
893
894   // Sometimes .init_array*, .preinit_array* and .fini_array* do not have
895   // correct section types.  Force them here.
896   elfcpp::Elf_Word sh_type = shdr.get_sh_type();
897   if (sh_type == elfcpp::SHT_PROGBITS)
898     {
899       static const char init_array_prefix[] = ".init_array";
900       static const char preinit_array_prefix[] = ".preinit_array";
901       static const char fini_array_prefix[] = ".fini_array";
902       static size_t init_array_prefix_size = sizeof(init_array_prefix) - 1;
903       static size_t preinit_array_prefix_size =
904         sizeof(preinit_array_prefix) - 1;
905       static size_t fini_array_prefix_size = sizeof(fini_array_prefix) - 1;
906
907       if (strncmp(name, init_array_prefix, init_array_prefix_size) == 0)
908         sh_type = elfcpp::SHT_INIT_ARRAY;
909       else if (strncmp(name, preinit_array_prefix, preinit_array_prefix_size)
910                == 0)
911         sh_type = elfcpp::SHT_PREINIT_ARRAY;
912       else if (strncmp(name, fini_array_prefix, fini_array_prefix_size) == 0)
913         sh_type = elfcpp::SHT_FINI_ARRAY;
914     }
915
916   // In a relocatable link a grouped section must not be combined with
917   // any other sections.
918   if (parameters->options().relocatable()
919       && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
920     {
921       name = this->namepool_.add(name, true, NULL);
922       os = this->make_output_section(name, sh_type, shdr.get_sh_flags(),
923                                      ORDER_INVALID, false);
924     }
925   else
926     {
927       os = this->choose_output_section(object, name, sh_type,
928                                        shdr.get_sh_flags(), true,
929                                        ORDER_INVALID, false);
930       if (os == NULL)
931         return NULL;
932     }
933
934   // By default the GNU linker sorts input sections whose names match
935   // .ctor.*, .dtor.*, .init_array.*, or .fini_array.*.  The sections
936   // are sorted by name.  This is used to implement constructor
937   // priority ordering.  We are compatible.
938   if (!this->script_options_->saw_sections_clause()
939       && (is_prefix_of(".ctors.", name)
940           || is_prefix_of(".dtors.", name)
941           || is_prefix_of(".init_array.", name)
942           || is_prefix_of(".fini_array.", name)))
943     os->set_must_sort_attached_input_sections();
944
945   // FIXME: Handle SHF_LINK_ORDER somewhere.
946
947   elfcpp::Elf_Xword orig_flags = os->flags();
948
949   *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
950                                this->script_options_->saw_sections_clause());
951
952   // If the flags changed, we may have to change the order.
953   if ((orig_flags & elfcpp::SHF_ALLOC) != 0)
954     {
955       orig_flags &= (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
956       elfcpp::Elf_Xword new_flags =
957         os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
958       if (orig_flags != new_flags)
959         os->set_order(this->default_section_order(os, false));
960     }
961
962   this->have_added_input_section_ = true;
963
964   return os;
965 }
966
967 // Handle a relocation section when doing a relocatable link.
968
969 template<int size, bool big_endian>
970 Output_section*
971 Layout::layout_reloc(Sized_relobj_file<size, big_endian>* object,
972                      unsigned int,
973                      const elfcpp::Shdr<size, big_endian>& shdr,
974                      Output_section* data_section,
975                      Relocatable_relocs* rr)
976 {
977   gold_assert(parameters->options().relocatable()
978               || parameters->options().emit_relocs());
979
980   int sh_type = shdr.get_sh_type();
981
982   std::string name;
983   if (sh_type == elfcpp::SHT_REL)
984     name = ".rel";
985   else if (sh_type == elfcpp::SHT_RELA)
986     name = ".rela";
987   else
988     gold_unreachable();
989   name += data_section->name();
990
991   // In a relocatable link relocs for a grouped section must not be
992   // combined with other reloc sections.
993   Output_section* os;
994   if (!parameters->options().relocatable()
995       || (data_section->flags() & elfcpp::SHF_GROUP) == 0)
996     os = this->choose_output_section(object, name.c_str(), sh_type,
997                                      shdr.get_sh_flags(), false,
998                                      ORDER_INVALID, false);
999   else
1000     {
1001       const char* n = this->namepool_.add(name.c_str(), true, NULL);
1002       os = this->make_output_section(n, sh_type, shdr.get_sh_flags(),
1003                                      ORDER_INVALID, false);
1004     }
1005
1006   os->set_should_link_to_symtab();
1007   os->set_info_section(data_section);
1008
1009   Output_section_data* posd;
1010   if (sh_type == elfcpp::SHT_REL)
1011     {
1012       os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
1013       posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
1014                                            size,
1015                                            big_endian>(rr);
1016     }
1017   else if (sh_type == elfcpp::SHT_RELA)
1018     {
1019       os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
1020       posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
1021                                            size,
1022                                            big_endian>(rr);
1023     }
1024   else
1025     gold_unreachable();
1026
1027   os->add_output_section_data(posd);
1028   rr->set_output_data(posd);
1029
1030   return os;
1031 }
1032
1033 // Handle a group section when doing a relocatable link.
1034
1035 template<int size, bool big_endian>
1036 void
1037 Layout::layout_group(Symbol_table* symtab,
1038                      Sized_relobj_file<size, big_endian>* object,
1039                      unsigned int,
1040                      const char* group_section_name,
1041                      const char* signature,
1042                      const elfcpp::Shdr<size, big_endian>& shdr,
1043                      elfcpp::Elf_Word flags,
1044                      std::vector<unsigned int>* shndxes)
1045 {
1046   gold_assert(parameters->options().relocatable());
1047   gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
1048   group_section_name = this->namepool_.add(group_section_name, true, NULL);
1049   Output_section* os = this->make_output_section(group_section_name,
1050                                                  elfcpp::SHT_GROUP,
1051                                                  shdr.get_sh_flags(),
1052                                                  ORDER_INVALID, false);
1053
1054   // We need to find a symbol with the signature in the symbol table.
1055   // If we don't find one now, we need to look again later.
1056   Symbol* sym = symtab->lookup(signature, NULL);
1057   if (sym != NULL)
1058     os->set_info_symndx(sym);
1059   else
1060     {
1061       // Reserve some space to minimize reallocations.
1062       if (this->group_signatures_.empty())
1063         this->group_signatures_.reserve(this->number_of_input_files_ * 16);
1064
1065       // We will wind up using a symbol whose name is the signature.
1066       // So just put the signature in the symbol name pool to save it.
1067       signature = symtab->canonicalize_name(signature);
1068       this->group_signatures_.push_back(Group_signature(os, signature));
1069     }
1070
1071   os->set_should_link_to_symtab();
1072   os->set_entsize(4);
1073
1074   section_size_type entry_count =
1075     convert_to_section_size_type(shdr.get_sh_size() / 4);
1076   Output_section_data* posd =
1077     new Output_data_group<size, big_endian>(object, entry_count, flags,
1078                                             shndxes);
1079   os->add_output_section_data(posd);
1080 }
1081
1082 // Special GNU handling of sections name .eh_frame.  They will
1083 // normally hold exception frame data as defined by the C++ ABI
1084 // (http://codesourcery.com/cxx-abi/).
1085
1086 template<int size, bool big_endian>
1087 Output_section*
1088 Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
1089                         const unsigned char* symbols,
1090                         off_t symbols_size,
1091                         const unsigned char* symbol_names,
1092                         off_t symbol_names_size,
1093                         unsigned int shndx,
1094                         const elfcpp::Shdr<size, big_endian>& shdr,
1095                         unsigned int reloc_shndx, unsigned int reloc_type,
1096                         off_t* off)
1097 {
1098   gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS);
1099   gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
1100
1101   const char* const name = ".eh_frame";
1102   Output_section* os = this->choose_output_section(object, name,
1103                                                    elfcpp::SHT_PROGBITS,
1104                                                    elfcpp::SHF_ALLOC, false,
1105                                                    ORDER_EHFRAME, false);
1106   if (os == NULL)
1107     return NULL;
1108
1109   if (this->eh_frame_section_ == NULL)
1110     {
1111       this->eh_frame_section_ = os;
1112       this->eh_frame_data_ = new Eh_frame();
1113
1114       // For incremental linking, we do not optimize .eh_frame sections
1115       // or create a .eh_frame_hdr section.
1116       if (parameters->options().eh_frame_hdr() && !parameters->incremental())
1117         {
1118           Output_section* hdr_os =
1119             this->choose_output_section(NULL, ".eh_frame_hdr",
1120                                         elfcpp::SHT_PROGBITS,
1121                                         elfcpp::SHF_ALLOC, false,
1122                                         ORDER_EHFRAME, false);
1123
1124           if (hdr_os != NULL)
1125             {
1126               Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
1127                                                         this->eh_frame_data_);
1128               hdr_os->add_output_section_data(hdr_posd);
1129
1130               hdr_os->set_after_input_sections();
1131
1132               if (!this->script_options_->saw_phdrs_clause())
1133                 {
1134                   Output_segment* hdr_oseg;
1135                   hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
1136                                                        elfcpp::PF_R);
1137                   hdr_oseg->add_output_section_to_nonload(hdr_os,
1138                                                           elfcpp::PF_R);
1139                 }
1140
1141               this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
1142             }
1143         }
1144     }
1145
1146   gold_assert(this->eh_frame_section_ == os);
1147
1148   if (!parameters->incremental()
1149       && this->eh_frame_data_->add_ehframe_input_section(object,
1150                                                          symbols,
1151                                                          symbols_size,
1152                                                          symbol_names,
1153                                                          symbol_names_size,
1154                                                          shndx,
1155                                                          reloc_shndx,
1156                                                          reloc_type))
1157     {
1158       os->update_flags_for_input_section(shdr.get_sh_flags());
1159
1160       // A writable .eh_frame section is a RELRO section.
1161       if ((shdr.get_sh_flags() & elfcpp::SHF_WRITE) != 0)
1162         os->set_is_relro();
1163
1164       // We found a .eh_frame section we are going to optimize, so now
1165       // we can add the set of optimized sections to the output
1166       // section.  We need to postpone adding this until we've found a
1167       // section we can optimize so that the .eh_frame section in
1168       // crtbegin.o winds up at the start of the output section.
1169       if (!this->added_eh_frame_data_)
1170         {
1171           os->add_output_section_data(this->eh_frame_data_);
1172           this->added_eh_frame_data_ = true;
1173         }
1174       *off = -1;
1175     }
1176   else
1177     {
1178       // We couldn't handle this .eh_frame section for some reason.
1179       // Add it as a normal section.
1180       bool saw_sections_clause = this->script_options_->saw_sections_clause();
1181       *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
1182                                    saw_sections_clause);
1183       this->have_added_input_section_ = true;
1184     }
1185
1186   return os;
1187 }
1188
1189 // Add POSD to an output section using NAME, TYPE, and FLAGS.  Return
1190 // the output section.
1191
1192 Output_section*
1193 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
1194                                 elfcpp::Elf_Xword flags,
1195                                 Output_section_data* posd,
1196                                 Output_section_order order, bool is_relro)
1197 {
1198   Output_section* os = this->choose_output_section(NULL, name, type, flags,
1199                                                    false, order, is_relro);
1200   if (os != NULL)
1201     os->add_output_section_data(posd);
1202   return os;
1203 }
1204
1205 // Map section flags to segment flags.
1206
1207 elfcpp::Elf_Word
1208 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
1209 {
1210   elfcpp::Elf_Word ret = elfcpp::PF_R;
1211   if ((flags & elfcpp::SHF_WRITE) != 0)
1212     ret |= elfcpp::PF_W;
1213   if ((flags & elfcpp::SHF_EXECINSTR) != 0)
1214     ret |= elfcpp::PF_X;
1215   return ret;
1216 }
1217
1218 // Make a new Output_section, and attach it to segments as
1219 // appropriate.  ORDER is the order in which this section should
1220 // appear in the output segment.  IS_RELRO is true if this is a relro
1221 // (read-only after relocations) section.
1222
1223 Output_section*
1224 Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
1225                             elfcpp::Elf_Xword flags,
1226                             Output_section_order order, bool is_relro)
1227 {
1228   Output_section* os;
1229   if ((flags & elfcpp::SHF_ALLOC) == 0
1230       && strcmp(parameters->options().compress_debug_sections(), "none") != 0
1231       && is_compressible_debug_section(name))
1232     os = new Output_compressed_section(&parameters->options(), name, type,
1233                                        flags);
1234   else if ((flags & elfcpp::SHF_ALLOC) == 0
1235            && parameters->options().strip_debug_non_line()
1236            && strcmp(".debug_abbrev", name) == 0)
1237     {
1238       os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
1239           name, type, flags);
1240       if (this->debug_info_)
1241         this->debug_info_->set_abbreviations(this->debug_abbrev_);
1242     }
1243   else if ((flags & elfcpp::SHF_ALLOC) == 0
1244            && parameters->options().strip_debug_non_line()
1245            && strcmp(".debug_info", name) == 0)
1246     {
1247       os = this->debug_info_ = new Output_reduced_debug_info_section(
1248           name, type, flags);
1249       if (this->debug_abbrev_)
1250         this->debug_info_->set_abbreviations(this->debug_abbrev_);
1251     }
1252   else
1253     {
1254       // FIXME: const_cast is ugly.
1255       Target* target = const_cast<Target*>(&parameters->target());
1256       os = target->make_output_section(name, type, flags);
1257     }
1258
1259   // With -z relro, we have to recognize the special sections by name.
1260   // There is no other way.
1261   bool is_relro_local = false;
1262   if (!this->script_options_->saw_sections_clause()
1263       && parameters->options().relro()
1264       && type == elfcpp::SHT_PROGBITS
1265       && (flags & elfcpp::SHF_ALLOC) != 0
1266       && (flags & elfcpp::SHF_WRITE) != 0)
1267     {
1268       if (strcmp(name, ".data.rel.ro") == 0)
1269         is_relro = true;
1270       else if (strcmp(name, ".data.rel.ro.local") == 0)
1271         {
1272           is_relro = true;
1273           is_relro_local = true;
1274         }
1275       else if (type == elfcpp::SHT_INIT_ARRAY
1276                || type == elfcpp::SHT_FINI_ARRAY
1277                || type == elfcpp::SHT_PREINIT_ARRAY)
1278         is_relro = true;
1279       else if (strcmp(name, ".ctors") == 0
1280                || strcmp(name, ".dtors") == 0
1281                || strcmp(name, ".jcr") == 0)
1282         is_relro = true;
1283     }
1284
1285   if (is_relro)
1286     os->set_is_relro();
1287
1288   if (order == ORDER_INVALID && (flags & elfcpp::SHF_ALLOC) != 0)
1289     order = this->default_section_order(os, is_relro_local);
1290
1291   os->set_order(order);
1292
1293   parameters->target().new_output_section(os);
1294
1295   this->section_list_.push_back(os);
1296
1297   // The GNU linker by default sorts some sections by priority, so we
1298   // do the same.  We need to know that this might happen before we
1299   // attach any input sections.
1300   if (!this->script_options_->saw_sections_clause()
1301       && (strcmp(name, ".ctors") == 0
1302           || strcmp(name, ".dtors") == 0
1303           || strcmp(name, ".init_array") == 0
1304           || strcmp(name, ".fini_array") == 0))
1305     os->set_may_sort_attached_input_sections();
1306
1307   // Check for .stab*str sections, as .stab* sections need to link to
1308   // them.
1309   if (type == elfcpp::SHT_STRTAB
1310       && !this->have_stabstr_section_
1311       && strncmp(name, ".stab", 5) == 0
1312       && strcmp(name + strlen(name) - 3, "str") == 0)
1313     this->have_stabstr_section_ = true;
1314
1315   // If we have already attached the sections to segments, then we
1316   // need to attach this one now.  This happens for sections created
1317   // directly by the linker.
1318   if (this->sections_are_attached_)
1319     this->attach_section_to_segment(os);
1320
1321   return os;
1322 }
1323
1324 // Return the default order in which a section should be placed in an
1325 // output segment.  This function captures a lot of the ideas in
1326 // ld/scripttempl/elf.sc in the GNU linker.  Note that the order of a
1327 // linker created section is normally set when the section is created;
1328 // this function is used for input sections.
1329
1330 Output_section_order
1331 Layout::default_section_order(Output_section* os, bool is_relro_local)
1332 {
1333   gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
1334   bool is_write = (os->flags() & elfcpp::SHF_WRITE) != 0;
1335   bool is_execinstr = (os->flags() & elfcpp::SHF_EXECINSTR) != 0;
1336   bool is_bss = false;
1337
1338   switch (os->type())
1339     {
1340     default:
1341     case elfcpp::SHT_PROGBITS:
1342       break;
1343     case elfcpp::SHT_NOBITS:
1344       is_bss = true;
1345       break;
1346     case elfcpp::SHT_RELA:
1347     case elfcpp::SHT_REL:
1348       if (!is_write)
1349         return ORDER_DYNAMIC_RELOCS;
1350       break;
1351     case elfcpp::SHT_HASH:
1352     case elfcpp::SHT_DYNAMIC:
1353     case elfcpp::SHT_SHLIB:
1354     case elfcpp::SHT_DYNSYM:
1355     case elfcpp::SHT_GNU_HASH:
1356     case elfcpp::SHT_GNU_verdef:
1357     case elfcpp::SHT_GNU_verneed:
1358     case elfcpp::SHT_GNU_versym:
1359       if (!is_write)
1360         return ORDER_DYNAMIC_LINKER;
1361       break;
1362     case elfcpp::SHT_NOTE:
1363       return is_write ? ORDER_RW_NOTE : ORDER_RO_NOTE;
1364     }
1365
1366   if ((os->flags() & elfcpp::SHF_TLS) != 0)
1367     return is_bss ? ORDER_TLS_BSS : ORDER_TLS_DATA;
1368
1369   if (!is_bss && !is_write)
1370     {
1371       if (is_execinstr)
1372         {
1373           if (strcmp(os->name(), ".init") == 0)
1374             return ORDER_INIT;
1375           else if (strcmp(os->name(), ".fini") == 0)
1376             return ORDER_FINI;
1377         }
1378       return is_execinstr ? ORDER_TEXT : ORDER_READONLY;
1379     }
1380
1381   if (os->is_relro())
1382     return is_relro_local ? ORDER_RELRO_LOCAL : ORDER_RELRO;
1383
1384   if (os->is_small_section())
1385     return is_bss ? ORDER_SMALL_BSS : ORDER_SMALL_DATA;
1386   if (os->is_large_section())
1387     return is_bss ? ORDER_LARGE_BSS : ORDER_LARGE_DATA;
1388
1389   return is_bss ? ORDER_BSS : ORDER_DATA;
1390 }
1391
1392 // Attach output sections to segments.  This is called after we have
1393 // seen all the input sections.
1394
1395 void
1396 Layout::attach_sections_to_segments()
1397 {
1398   for (Section_list::iterator p = this->section_list_.begin();
1399        p != this->section_list_.end();
1400        ++p)
1401     this->attach_section_to_segment(*p);
1402
1403   this->sections_are_attached_ = true;
1404 }
1405
1406 // Attach an output section to a segment.
1407
1408 void
1409 Layout::attach_section_to_segment(Output_section* os)
1410 {
1411   if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
1412     this->unattached_section_list_.push_back(os);
1413   else
1414     this->attach_allocated_section_to_segment(os);
1415 }
1416
1417 // Attach an allocated output section to a segment.
1418
1419 void
1420 Layout::attach_allocated_section_to_segment(Output_section* os)
1421 {
1422   elfcpp::Elf_Xword flags = os->flags();
1423   gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
1424
1425   if (parameters->options().relocatable())
1426     return;
1427
1428   // If we have a SECTIONS clause, we can't handle the attachment to
1429   // segments until after we've seen all the sections.
1430   if (this->script_options_->saw_sections_clause())
1431     return;
1432
1433   gold_assert(!this->script_options_->saw_phdrs_clause());
1434
1435   // This output section goes into a PT_LOAD segment.
1436
1437   elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
1438
1439   // Check for --section-start.
1440   uint64_t addr;
1441   bool is_address_set = parameters->options().section_start(os->name(), &addr);
1442
1443   // In general the only thing we really care about for PT_LOAD
1444   // segments is whether or not they are writable or executable,
1445   // so that is how we search for them.
1446   // Large data sections also go into their own PT_LOAD segment.
1447   // People who need segments sorted on some other basis will
1448   // have to use a linker script.
1449
1450   Segment_list::const_iterator p;
1451   for (p = this->segment_list_.begin();
1452        p != this->segment_list_.end();
1453        ++p)
1454     {
1455       if ((*p)->type() != elfcpp::PT_LOAD)
1456         continue;
1457       if (!parameters->options().omagic()
1458           && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
1459         continue;
1460       if (parameters->options().rosegment()
1461           && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
1462         continue;
1463       // If -Tbss was specified, we need to separate the data and BSS
1464       // segments.
1465       if (parameters->options().user_set_Tbss())
1466         {
1467           if ((os->type() == elfcpp::SHT_NOBITS)
1468               == (*p)->has_any_data_sections())
1469             continue;
1470         }
1471       if (os->is_large_data_section() && !(*p)->is_large_data_segment())
1472         continue;
1473
1474       if (is_address_set)
1475         {
1476           if ((*p)->are_addresses_set())
1477             continue;
1478
1479           (*p)->add_initial_output_data(os);
1480           (*p)->update_flags_for_output_section(seg_flags);
1481           (*p)->set_addresses(addr, addr);
1482           break;
1483         }
1484
1485       (*p)->add_output_section_to_load(this, os, seg_flags);
1486       break;
1487     }
1488
1489   if (p == this->segment_list_.end())
1490     {
1491       Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
1492                                                        seg_flags);
1493       if (os->is_large_data_section())
1494         oseg->set_is_large_data_segment();
1495       oseg->add_output_section_to_load(this, os, seg_flags);
1496       if (is_address_set)
1497         oseg->set_addresses(addr, addr);
1498     }
1499
1500   // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1501   // segment.
1502   if (os->type() == elfcpp::SHT_NOTE)
1503     {
1504       // See if we already have an equivalent PT_NOTE segment.
1505       for (p = this->segment_list_.begin();
1506            p != segment_list_.end();
1507            ++p)
1508         {
1509           if ((*p)->type() == elfcpp::PT_NOTE
1510               && (((*p)->flags() & elfcpp::PF_W)
1511                   == (seg_flags & elfcpp::PF_W)))
1512             {
1513               (*p)->add_output_section_to_nonload(os, seg_flags);
1514               break;
1515             }
1516         }
1517
1518       if (p == this->segment_list_.end())
1519         {
1520           Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
1521                                                            seg_flags);
1522           oseg->add_output_section_to_nonload(os, seg_flags);
1523         }
1524     }
1525
1526   // If we see a loadable SHF_TLS section, we create a PT_TLS
1527   // segment.  There can only be one such segment.
1528   if ((flags & elfcpp::SHF_TLS) != 0)
1529     {
1530       if (this->tls_segment_ == NULL)
1531         this->make_output_segment(elfcpp::PT_TLS, seg_flags);
1532       this->tls_segment_->add_output_section_to_nonload(os, seg_flags);
1533     }
1534
1535   // If -z relro is in effect, and we see a relro section, we create a
1536   // PT_GNU_RELRO segment.  There can only be one such segment.
1537   if (os->is_relro() && parameters->options().relro())
1538     {
1539       gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
1540       if (this->relro_segment_ == NULL)
1541         this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
1542       this->relro_segment_->add_output_section_to_nonload(os, seg_flags);
1543     }
1544 }
1545
1546 // Make an output section for a script.
1547
1548 Output_section*
1549 Layout::make_output_section_for_script(
1550     const char* name,
1551     Script_sections::Section_type section_type)
1552 {
1553   name = this->namepool_.add(name, false, NULL);
1554   elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC;
1555   if (section_type == Script_sections::ST_NOLOAD)
1556     sh_flags = 0;
1557   Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
1558                                                  sh_flags, ORDER_INVALID,
1559                                                  false);
1560   os->set_found_in_sections_clause();
1561   if (section_type == Script_sections::ST_NOLOAD)
1562     os->set_is_noload();
1563   return os;
1564 }
1565
1566 // Return the number of segments we expect to see.
1567
1568 size_t
1569 Layout::expected_segment_count() const
1570 {
1571   size_t ret = this->segment_list_.size();
1572
1573   // If we didn't see a SECTIONS clause in a linker script, we should
1574   // already have the complete list of segments.  Otherwise we ask the
1575   // SECTIONS clause how many segments it expects, and add in the ones
1576   // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
1577
1578   if (!this->script_options_->saw_sections_clause())
1579     return ret;
1580   else
1581     {
1582       const Script_sections* ss = this->script_options_->script_sections();
1583       return ret + ss->expected_segment_count(this);
1584     }
1585 }
1586
1587 // Handle the .note.GNU-stack section at layout time.  SEEN_GNU_STACK
1588 // is whether we saw a .note.GNU-stack section in the object file.
1589 // GNU_STACK_FLAGS is the section flags.  The flags give the
1590 // protection required for stack memory.  We record this in an
1591 // executable as a PT_GNU_STACK segment.  If an object file does not
1592 // have a .note.GNU-stack segment, we must assume that it is an old
1593 // object.  On some targets that will force an executable stack.
1594
1595 void
1596 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags,
1597                          const Object* obj)
1598 {
1599   if (!seen_gnu_stack)
1600     {
1601       this->input_without_gnu_stack_note_ = true;
1602       if (parameters->options().warn_execstack()
1603           && parameters->target().is_default_stack_executable())
1604         gold_warning(_("%s: missing .note.GNU-stack section"
1605                        " implies executable stack"),
1606                      obj->name().c_str());
1607     }
1608   else
1609     {
1610       this->input_with_gnu_stack_note_ = true;
1611       if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
1612         {
1613           this->input_requires_executable_stack_ = true;
1614           if (parameters->options().warn_execstack()
1615               || parameters->options().is_stack_executable())
1616             gold_warning(_("%s: requires executable stack"),
1617                          obj->name().c_str());
1618         }
1619     }
1620 }
1621
1622 // Create automatic note sections.
1623
1624 void
1625 Layout::create_notes()
1626 {
1627   this->create_gold_note();
1628   this->create_executable_stack_info();
1629   this->create_build_id();
1630 }
1631
1632 // Create the dynamic sections which are needed before we read the
1633 // relocs.
1634
1635 void
1636 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
1637 {
1638   if (parameters->doing_static_link())
1639     return;
1640
1641   this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
1642                                                        elfcpp::SHT_DYNAMIC,
1643                                                        (elfcpp::SHF_ALLOC
1644                                                         | elfcpp::SHF_WRITE),
1645                                                        false, ORDER_RELRO,
1646                                                        true);
1647
1648   this->dynamic_symbol_ =
1649     symtab->define_in_output_data("_DYNAMIC", NULL, Symbol_table::PREDEFINED,
1650                                   this->dynamic_section_, 0, 0,
1651                                   elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
1652                                   elfcpp::STV_HIDDEN, 0, false, false);
1653
1654   this->dynamic_data_ =  new Output_data_dynamic(&this->dynpool_);
1655
1656   this->dynamic_section_->add_output_section_data(this->dynamic_data_);
1657 }
1658
1659 // For each output section whose name can be represented as C symbol,
1660 // define __start and __stop symbols for the section.  This is a GNU
1661 // extension.
1662
1663 void
1664 Layout::define_section_symbols(Symbol_table* symtab)
1665 {
1666   for (Section_list::const_iterator p = this->section_list_.begin();
1667        p != this->section_list_.end();
1668        ++p)
1669     {
1670       const char* const name = (*p)->name();
1671       if (is_cident(name))
1672         {
1673           const std::string name_string(name);
1674           const std::string start_name(cident_section_start_prefix
1675                                        + name_string);
1676           const std::string stop_name(cident_section_stop_prefix
1677                                       + name_string);
1678
1679           symtab->define_in_output_data(start_name.c_str(),
1680                                         NULL, // version
1681                                         Symbol_table::PREDEFINED,
1682                                         *p,
1683                                         0, // value
1684                                         0, // symsize
1685                                         elfcpp::STT_NOTYPE,
1686                                         elfcpp::STB_GLOBAL,
1687                                         elfcpp::STV_DEFAULT,
1688                                         0, // nonvis
1689                                         false, // offset_is_from_end
1690                                         true); // only_if_ref
1691
1692           symtab->define_in_output_data(stop_name.c_str(),
1693                                         NULL, // version
1694                                         Symbol_table::PREDEFINED,
1695                                         *p,
1696                                         0, // value
1697                                         0, // symsize
1698                                         elfcpp::STT_NOTYPE,
1699                                         elfcpp::STB_GLOBAL,
1700                                         elfcpp::STV_DEFAULT,
1701                                         0, // nonvis
1702                                         true, // offset_is_from_end
1703                                         true); // only_if_ref
1704         }
1705     }
1706 }
1707
1708 // Define symbols for group signatures.
1709
1710 void
1711 Layout::define_group_signatures(Symbol_table* symtab)
1712 {
1713   for (Group_signatures::iterator p = this->group_signatures_.begin();
1714        p != this->group_signatures_.end();
1715        ++p)
1716     {
1717       Symbol* sym = symtab->lookup(p->signature, NULL);
1718       if (sym != NULL)
1719         p->section->set_info_symndx(sym);
1720       else
1721         {
1722           // Force the name of the group section to the group
1723           // signature, and use the group's section symbol as the
1724           // signature symbol.
1725           if (strcmp(p->section->name(), p->signature) != 0)
1726             {
1727               const char* name = this->namepool_.add(p->signature,
1728                                                      true, NULL);
1729               p->section->set_name(name);
1730             }
1731           p->section->set_needs_symtab_index();
1732           p->section->set_info_section_symndx(p->section);
1733         }
1734     }
1735
1736   this->group_signatures_.clear();
1737 }
1738
1739 // Find the first read-only PT_LOAD segment, creating one if
1740 // necessary.
1741
1742 Output_segment*
1743 Layout::find_first_load_seg()
1744 {
1745   Output_segment* best = NULL;
1746   for (Segment_list::const_iterator p = this->segment_list_.begin();
1747        p != this->segment_list_.end();
1748        ++p)
1749     {
1750       if ((*p)->type() == elfcpp::PT_LOAD
1751           && ((*p)->flags() & elfcpp::PF_R) != 0
1752           && (parameters->options().omagic()
1753               || ((*p)->flags() & elfcpp::PF_W) == 0))
1754         {
1755           if (best == NULL || this->segment_precedes(*p, best))
1756             best = *p;
1757         }
1758     }
1759   if (best != NULL)
1760     return best;
1761
1762   gold_assert(!this->script_options_->saw_phdrs_clause());
1763
1764   Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
1765                                                        elfcpp::PF_R);
1766   return load_seg;
1767 }
1768
1769 // Save states of all current output segments.  Store saved states
1770 // in SEGMENT_STATES.
1771
1772 void
1773 Layout::save_segments(Segment_states* segment_states)
1774 {
1775   for (Segment_list::const_iterator p = this->segment_list_.begin();
1776        p != this->segment_list_.end();
1777        ++p)
1778     {
1779       Output_segment* segment = *p;
1780       // Shallow copy.
1781       Output_segment* copy = new Output_segment(*segment);
1782       (*segment_states)[segment] = copy;
1783     }
1784 }
1785
1786 // Restore states of output segments and delete any segment not found in
1787 // SEGMENT_STATES.
1788
1789 void
1790 Layout::restore_segments(const Segment_states* segment_states)
1791 {
1792   // Go through the segment list and remove any segment added in the
1793   // relaxation loop.
1794   this->tls_segment_ = NULL;
1795   this->relro_segment_ = NULL;
1796   Segment_list::iterator list_iter = this->segment_list_.begin();
1797   while (list_iter != this->segment_list_.end())
1798     {
1799       Output_segment* segment = *list_iter;
1800       Segment_states::const_iterator states_iter =
1801           segment_states->find(segment);
1802       if (states_iter != segment_states->end())
1803         {
1804           const Output_segment* copy = states_iter->second;
1805           // Shallow copy to restore states.
1806           *segment = *copy;
1807
1808           // Also fix up TLS and RELRO segment pointers as appropriate.
1809           if (segment->type() == elfcpp::PT_TLS)
1810             this->tls_segment_ = segment;
1811           else if (segment->type() == elfcpp::PT_GNU_RELRO)
1812             this->relro_segment_ = segment;
1813
1814           ++list_iter;
1815         } 
1816       else
1817         {
1818           list_iter = this->segment_list_.erase(list_iter); 
1819           // This is a segment created during section layout.  It should be
1820           // safe to remove it since we should have removed all pointers to it.
1821           delete segment;
1822         }
1823     }
1824 }
1825
1826 // Clean up after relaxation so that sections can be laid out again.
1827
1828 void
1829 Layout::clean_up_after_relaxation()
1830 {
1831   // Restore the segments to point state just prior to the relaxation loop.
1832   Script_sections* script_section = this->script_options_->script_sections();
1833   script_section->release_segments();
1834   this->restore_segments(this->segment_states_);
1835
1836   // Reset section addresses and file offsets
1837   for (Section_list::iterator p = this->section_list_.begin();
1838        p != this->section_list_.end();
1839        ++p)
1840     {
1841       (*p)->restore_states();
1842
1843       // If an input section changes size because of relaxation,
1844       // we need to adjust the section offsets of all input sections.
1845       // after such a section.
1846       if ((*p)->section_offsets_need_adjustment())
1847         (*p)->adjust_section_offsets();
1848
1849       (*p)->reset_address_and_file_offset();
1850     }
1851   
1852   // Reset special output object address and file offsets.
1853   for (Data_list::iterator p = this->special_output_list_.begin();
1854        p != this->special_output_list_.end();
1855        ++p)
1856     (*p)->reset_address_and_file_offset();
1857
1858   // A linker script may have created some output section data objects.
1859   // They are useless now.
1860   for (Output_section_data_list::const_iterator p =
1861          this->script_output_section_data_list_.begin();
1862        p != this->script_output_section_data_list_.end();
1863        ++p)
1864     delete *p;
1865   this->script_output_section_data_list_.clear(); 
1866 }
1867
1868 // Prepare for relaxation.
1869
1870 void
1871 Layout::prepare_for_relaxation()
1872 {
1873   // Create an relaxation debug check if in debugging mode.
1874   if (is_debugging_enabled(DEBUG_RELAXATION))
1875     this->relaxation_debug_check_ = new Relaxation_debug_check();
1876
1877   // Save segment states.
1878   this->segment_states_ = new Segment_states();
1879   this->save_segments(this->segment_states_);
1880
1881   for(Section_list::const_iterator p = this->section_list_.begin();
1882       p != this->section_list_.end();
1883       ++p)
1884     (*p)->save_states();
1885
1886   if (is_debugging_enabled(DEBUG_RELAXATION))
1887     this->relaxation_debug_check_->check_output_data_for_reset_values(
1888         this->section_list_, this->special_output_list_);
1889
1890   // Also enable recording of output section data from scripts.
1891   this->record_output_section_data_from_script_ = true;
1892 }
1893
1894 // Relaxation loop body:  If target has no relaxation, this runs only once
1895 // Otherwise, the target relaxation hook is called at the end of
1896 // each iteration.  If the hook returns true, it means re-layout of
1897 // section is required.  
1898 //
1899 // The number of segments created by a linking script without a PHDRS
1900 // clause may be affected by section sizes and alignments.  There is
1901 // a remote chance that relaxation causes different number of PT_LOAD
1902 // segments are created and sections are attached to different segments.
1903 // Therefore, we always throw away all segments created during section
1904 // layout.  In order to be able to restart the section layout, we keep
1905 // a copy of the segment list right before the relaxation loop and use
1906 // that to restore the segments.
1907 // 
1908 // PASS is the current relaxation pass number. 
1909 // SYMTAB is a symbol table.
1910 // PLOAD_SEG is the address of a pointer for the load segment.
1911 // PHDR_SEG is a pointer to the PHDR segment.
1912 // SEGMENT_HEADERS points to the output segment header.
1913 // FILE_HEADER points to the output file header.
1914 // PSHNDX is the address to store the output section index.
1915
1916 off_t inline
1917 Layout::relaxation_loop_body(
1918     int pass,
1919     Target* target,
1920     Symbol_table* symtab,
1921     Output_segment** pload_seg,
1922     Output_segment* phdr_seg,
1923     Output_segment_headers* segment_headers,
1924     Output_file_header* file_header,
1925     unsigned int* pshndx)
1926 {
1927   // If this is not the first iteration, we need to clean up after
1928   // relaxation so that we can lay out the sections again.
1929   if (pass != 0)
1930     this->clean_up_after_relaxation();
1931
1932   // If there is a SECTIONS clause, put all the input sections into
1933   // the required order.
1934   Output_segment* load_seg;
1935   if (this->script_options_->saw_sections_clause())
1936     load_seg = this->set_section_addresses_from_script(symtab);
1937   else if (parameters->options().relocatable())
1938     load_seg = NULL;
1939   else
1940     load_seg = this->find_first_load_seg();
1941
1942   if (parameters->options().oformat_enum()
1943       != General_options::OBJECT_FORMAT_ELF)
1944     load_seg = NULL;
1945
1946   // If the user set the address of the text segment, that may not be
1947   // compatible with putting the segment headers and file headers into
1948   // that segment.
1949   if (parameters->options().user_set_Ttext())
1950     load_seg = NULL;
1951
1952   gold_assert(phdr_seg == NULL
1953               || load_seg != NULL
1954               || this->script_options_->saw_sections_clause());
1955
1956   // If the address of the load segment we found has been set by
1957   // --section-start rather than by a script, then adjust the VMA and
1958   // LMA downward if possible to include the file and section headers.
1959   uint64_t header_gap = 0;
1960   if (load_seg != NULL
1961       && load_seg->are_addresses_set()
1962       && !this->script_options_->saw_sections_clause()
1963       && !parameters->options().relocatable())
1964     {
1965       file_header->finalize_data_size();
1966       segment_headers->finalize_data_size();
1967       size_t sizeof_headers = (file_header->data_size()
1968                                + segment_headers->data_size());
1969       const uint64_t abi_pagesize = target->abi_pagesize();
1970       uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers;
1971       hdr_paddr &= ~(abi_pagesize - 1);
1972       uint64_t subtract = load_seg->paddr() - hdr_paddr;
1973       if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract)
1974         load_seg = NULL;
1975       else
1976         {
1977           load_seg->set_addresses(load_seg->vaddr() - subtract,
1978                                   load_seg->paddr() - subtract);
1979           header_gap = subtract - sizeof_headers;
1980         }
1981     }
1982
1983   // Lay out the segment headers.
1984   if (!parameters->options().relocatable())
1985     {
1986       gold_assert(segment_headers != NULL);
1987       if (header_gap != 0 && load_seg != NULL)
1988         {
1989           Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1);
1990           load_seg->add_initial_output_data(z);
1991         }
1992       if (load_seg != NULL)
1993         load_seg->add_initial_output_data(segment_headers);
1994       if (phdr_seg != NULL)
1995         phdr_seg->add_initial_output_data(segment_headers);
1996     }
1997
1998   // Lay out the file header.
1999   if (load_seg != NULL)
2000     load_seg->add_initial_output_data(file_header);
2001
2002   if (this->script_options_->saw_phdrs_clause()
2003       && !parameters->options().relocatable())
2004     {
2005       // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2006       // clause in a linker script.
2007       Script_sections* ss = this->script_options_->script_sections();
2008       ss->put_headers_in_phdrs(file_header, segment_headers);
2009     }
2010
2011   // We set the output section indexes in set_segment_offsets and
2012   // set_section_indexes.
2013   *pshndx = 1;
2014
2015   // Set the file offsets of all the segments, and all the sections
2016   // they contain.
2017   off_t off;
2018   if (!parameters->options().relocatable())
2019     off = this->set_segment_offsets(target, load_seg, pshndx);
2020   else
2021     off = this->set_relocatable_section_offsets(file_header, pshndx);
2022
2023    // Verify that the dummy relaxation does not change anything.
2024   if (is_debugging_enabled(DEBUG_RELAXATION))
2025     {
2026       if (pass == 0)
2027         this->relaxation_debug_check_->read_sections(this->section_list_);
2028       else
2029         this->relaxation_debug_check_->verify_sections(this->section_list_);
2030     }
2031
2032   *pload_seg = load_seg;
2033   return off;
2034 }
2035
2036 // Search the list of patterns and find the postion of the given section
2037 // name in the output section.  If the section name matches a glob
2038 // pattern and a non-glob name, then the non-glob position takes
2039 // precedence.  Return 0 if no match is found.
2040
2041 unsigned int
2042 Layout::find_section_order_index(const std::string& section_name)
2043 {
2044   Unordered_map<std::string, unsigned int>::iterator map_it;
2045   map_it = this->input_section_position_.find(section_name);
2046   if (map_it != this->input_section_position_.end())
2047     return map_it->second;
2048
2049   // Absolute match failed.  Linear search the glob patterns.
2050   std::vector<std::string>::iterator it;
2051   for (it = this->input_section_glob_.begin();
2052        it != this->input_section_glob_.end();
2053        ++it)
2054     {
2055        if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0)
2056          {
2057            map_it = this->input_section_position_.find(*it);
2058            gold_assert(map_it != this->input_section_position_.end());
2059            return map_it->second;
2060          }
2061     }
2062   return 0;
2063 }
2064
2065 // Read the sequence of input sections from the file specified with
2066 // --section-ordering-file.
2067
2068 void
2069 Layout::read_layout_from_file()
2070 {
2071   const char* filename = parameters->options().section_ordering_file();
2072   std::ifstream in;
2073   std::string line;
2074
2075   in.open(filename);
2076   if (!in)
2077     gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2078                filename, strerror(errno));
2079
2080   std::getline(in, line);   // this chops off the trailing \n, if any
2081   unsigned int position = 1;
2082
2083   while (in)
2084     {
2085       if (!line.empty() && line[line.length() - 1] == '\r')   // Windows
2086         line.resize(line.length() - 1);
2087       // Ignore comments, beginning with '#'
2088       if (line[0] == '#')
2089         {
2090           std::getline(in, line);
2091           continue;
2092         }
2093       this->input_section_position_[line] = position;
2094       // Store all glob patterns in a vector.
2095       if (is_wildcard_string(line.c_str()))
2096         this->input_section_glob_.push_back(line);
2097       position++;
2098       std::getline(in, line);
2099     }
2100 }
2101
2102 // Finalize the layout.  When this is called, we have created all the
2103 // output sections and all the output segments which are based on
2104 // input sections.  We have several things to do, and we have to do
2105 // them in the right order, so that we get the right results correctly
2106 // and efficiently.
2107
2108 // 1) Finalize the list of output segments and create the segment
2109 // table header.
2110
2111 // 2) Finalize the dynamic symbol table and associated sections.
2112
2113 // 3) Determine the final file offset of all the output segments.
2114
2115 // 4) Determine the final file offset of all the SHF_ALLOC output
2116 // sections.
2117
2118 // 5) Create the symbol table sections and the section name table
2119 // section.
2120
2121 // 6) Finalize the symbol table: set symbol values to their final
2122 // value and make a final determination of which symbols are going
2123 // into the output symbol table.
2124
2125 // 7) Create the section table header.
2126
2127 // 8) Determine the final file offset of all the output sections which
2128 // are not SHF_ALLOC, including the section table header.
2129
2130 // 9) Finalize the ELF file header.
2131
2132 // This function returns the size of the output file.
2133
2134 off_t
2135 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
2136                  Target* target, const Task* task)
2137 {
2138   target->finalize_sections(this, input_objects, symtab);
2139
2140   this->count_local_symbols(task, input_objects);
2141
2142   this->link_stabs_sections();
2143
2144   Output_segment* phdr_seg = NULL;
2145   if (!parameters->options().relocatable() && !parameters->doing_static_link())
2146     {
2147       // There was a dynamic object in the link.  We need to create
2148       // some information for the dynamic linker.
2149
2150       // Create the PT_PHDR segment which will hold the program
2151       // headers.
2152       if (!this->script_options_->saw_phdrs_clause())
2153         phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
2154
2155       // Create the dynamic symbol table, including the hash table.
2156       Output_section* dynstr;
2157       std::vector<Symbol*> dynamic_symbols;
2158       unsigned int local_dynamic_count;
2159       Versions versions(*this->script_options()->version_script_info(),
2160                         &this->dynpool_);
2161       this->create_dynamic_symtab(input_objects, symtab, &dynstr,
2162                                   &local_dynamic_count, &dynamic_symbols,
2163                                   &versions);
2164
2165       // Create the .interp section to hold the name of the
2166       // interpreter, and put it in a PT_INTERP segment.
2167       if (!parameters->options().shared())
2168         this->create_interp(target);
2169
2170       // Finish the .dynamic section to hold the dynamic data, and put
2171       // it in a PT_DYNAMIC segment.
2172       this->finish_dynamic_section(input_objects, symtab);
2173
2174       // We should have added everything we need to the dynamic string
2175       // table.
2176       this->dynpool_.set_string_offsets();
2177
2178       // Create the version sections.  We can't do this until the
2179       // dynamic string table is complete.
2180       this->create_version_sections(&versions, symtab, local_dynamic_count,
2181                                     dynamic_symbols, dynstr);
2182
2183       // Set the size of the _DYNAMIC symbol.  We can't do this until
2184       // after we call create_version_sections.
2185       this->set_dynamic_symbol_size(symtab);
2186     }
2187   
2188   // Create segment headers.
2189   Output_segment_headers* segment_headers =
2190     (parameters->options().relocatable()
2191      ? NULL
2192      : new Output_segment_headers(this->segment_list_));
2193
2194   // Lay out the file header.
2195   Output_file_header* file_header
2196     = new Output_file_header(target, symtab, segment_headers,
2197                              parameters->options().entry());
2198
2199   this->special_output_list_.push_back(file_header);
2200   if (segment_headers != NULL)
2201     this->special_output_list_.push_back(segment_headers);
2202
2203   // Find approriate places for orphan output sections if we are using
2204   // a linker script.
2205   if (this->script_options_->saw_sections_clause())
2206     this->place_orphan_sections_in_script();
2207   
2208   Output_segment* load_seg;
2209   off_t off;
2210   unsigned int shndx;
2211   int pass = 0;
2212
2213   // Take a snapshot of the section layout as needed.
2214   if (target->may_relax())
2215     this->prepare_for_relaxation();
2216   
2217   // Run the relaxation loop to lay out sections.
2218   do
2219     {
2220       off = this->relaxation_loop_body(pass, target, symtab, &load_seg,
2221                                        phdr_seg, segment_headers, file_header,
2222                                        &shndx);
2223       pass++;
2224     }
2225   while (target->may_relax()
2226          && target->relax(pass, input_objects, symtab, this, task));
2227
2228   // Set the file offsets of all the non-data sections we've seen so
2229   // far which don't have to wait for the input sections.  We need
2230   // this in order to finalize local symbols in non-allocated
2231   // sections.
2232   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2233
2234   // Set the section indexes of all unallocated sections seen so far,
2235   // in case any of them are somehow referenced by a symbol.
2236   shndx = this->set_section_indexes(shndx);
2237
2238   // Create the symbol table sections.
2239   this->create_symtab_sections(input_objects, symtab, shndx, &off);
2240   if (!parameters->doing_static_link())
2241     this->assign_local_dynsym_offsets(input_objects);
2242
2243   // Process any symbol assignments from a linker script.  This must
2244   // be called after the symbol table has been finalized.
2245   this->script_options_->finalize_symbols(symtab, this);
2246
2247   // Create the incremental inputs sections.
2248   if (this->incremental_inputs_)
2249     {
2250       this->incremental_inputs_->finalize();
2251       this->create_incremental_info_sections(symtab);
2252     }
2253
2254   // Create the .shstrtab section.
2255   Output_section* shstrtab_section = this->create_shstrtab();
2256
2257   // Set the file offsets of the rest of the non-data sections which
2258   // don't have to wait for the input sections.
2259   off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2260
2261   // Now that all sections have been created, set the section indexes
2262   // for any sections which haven't been done yet.
2263   shndx = this->set_section_indexes(shndx);
2264
2265   // Create the section table header.
2266   this->create_shdrs(shstrtab_section, &off);
2267
2268   // If there are no sections which require postprocessing, we can
2269   // handle the section names now, and avoid a resize later.
2270   if (!this->any_postprocessing_sections_)
2271     {
2272       off = this->set_section_offsets(off,
2273                                       POSTPROCESSING_SECTIONS_PASS);
2274       off =
2275           this->set_section_offsets(off,
2276                                     STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
2277     }
2278
2279   file_header->set_section_info(this->section_headers_, shstrtab_section);
2280
2281   // Now we know exactly where everything goes in the output file
2282   // (except for non-allocated sections which require postprocessing).
2283   Output_data::layout_complete();
2284
2285   this->output_file_size_ = off;
2286
2287   return off;
2288 }
2289
2290 // Create a note header following the format defined in the ELF ABI.
2291 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2292 // of the section to create, DESCSZ is the size of the descriptor.
2293 // ALLOCATE is true if the section should be allocated in memory.
2294 // This returns the new note section.  It sets *TRAILING_PADDING to
2295 // the number of trailing zero bytes required.
2296
2297 Output_section*
2298 Layout::create_note(const char* name, int note_type,
2299                     const char* section_name, size_t descsz,
2300                     bool allocate, size_t* trailing_padding)
2301 {
2302   // Authorities all agree that the values in a .note field should
2303   // be aligned on 4-byte boundaries for 32-bit binaries.  However,
2304   // they differ on what the alignment is for 64-bit binaries.
2305   // The GABI says unambiguously they take 8-byte alignment:
2306   //    http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2307   // Other documentation says alignment should always be 4 bytes:
2308   //    http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2309   // GNU ld and GNU readelf both support the latter (at least as of
2310   // version 2.16.91), and glibc always generates the latter for
2311   // .note.ABI-tag (as of version 1.6), so that's the one we go with
2312   // here.
2313 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION   // This is not defined by default.
2314   const int size = parameters->target().get_size();
2315 #else
2316   const int size = 32;
2317 #endif
2318
2319   // The contents of the .note section.
2320   size_t namesz = strlen(name) + 1;
2321   size_t aligned_namesz = align_address(namesz, size / 8);
2322   size_t aligned_descsz = align_address(descsz, size / 8);
2323
2324   size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
2325
2326   unsigned char* buffer = new unsigned char[notehdrsz];
2327   memset(buffer, 0, notehdrsz);
2328
2329   bool is_big_endian = parameters->target().is_big_endian();
2330
2331   if (size == 32)
2332     {
2333       if (!is_big_endian)
2334         {
2335           elfcpp::Swap<32, false>::writeval(buffer, namesz);
2336           elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
2337           elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
2338         }
2339       else
2340         {
2341           elfcpp::Swap<32, true>::writeval(buffer, namesz);
2342           elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
2343           elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
2344         }
2345     }
2346   else if (size == 64)
2347     {
2348       if (!is_big_endian)
2349         {
2350           elfcpp::Swap<64, false>::writeval(buffer, namesz);
2351           elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
2352           elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
2353         }
2354       else
2355         {
2356           elfcpp::Swap<64, true>::writeval(buffer, namesz);
2357           elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
2358           elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
2359         }
2360     }
2361   else
2362     gold_unreachable();
2363
2364   memcpy(buffer + 3 * (size / 8), name, namesz);
2365
2366   elfcpp::Elf_Xword flags = 0;
2367   Output_section_order order = ORDER_INVALID;
2368   if (allocate)
2369     {
2370       flags = elfcpp::SHF_ALLOC;
2371       order = ORDER_RO_NOTE;
2372     }
2373   Output_section* os = this->choose_output_section(NULL, section_name,
2374                                                    elfcpp::SHT_NOTE,
2375                                                    flags, false, order, false);
2376   if (os == NULL)
2377     return NULL;
2378
2379   Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
2380                                                            size / 8,
2381                                                            "** note header");
2382   os->add_output_section_data(posd);
2383
2384   *trailing_padding = aligned_descsz - descsz;
2385
2386   return os;
2387 }
2388
2389 // For an executable or shared library, create a note to record the
2390 // version of gold used to create the binary.
2391
2392 void
2393 Layout::create_gold_note()
2394 {
2395   if (parameters->options().relocatable()
2396       || parameters->incremental_update())
2397     return;
2398
2399   std::string desc = std::string("gold ") + gold::get_version_string();
2400
2401   size_t trailing_padding;
2402   Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
2403                                          ".note.gnu.gold-version", desc.size(),
2404                                          false, &trailing_padding);
2405   if (os == NULL)
2406     return;
2407
2408   Output_section_data* posd = new Output_data_const(desc, 4);
2409   os->add_output_section_data(posd);
2410
2411   if (trailing_padding > 0)
2412     {
2413       posd = new Output_data_zero_fill(trailing_padding, 0);
2414       os->add_output_section_data(posd);
2415     }
2416 }
2417
2418 // Record whether the stack should be executable.  This can be set
2419 // from the command line using the -z execstack or -z noexecstack
2420 // options.  Otherwise, if any input file has a .note.GNU-stack
2421 // section with the SHF_EXECINSTR flag set, the stack should be
2422 // executable.  Otherwise, if at least one input file a
2423 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2424 // section, we use the target default for whether the stack should be
2425 // executable.  Otherwise, we don't generate a stack note.  When
2426 // generating a object file, we create a .note.GNU-stack section with
2427 // the appropriate marking.  When generating an executable or shared
2428 // library, we create a PT_GNU_STACK segment.
2429
2430 void
2431 Layout::create_executable_stack_info()
2432 {
2433   bool is_stack_executable;
2434   if (parameters->options().is_execstack_set())
2435     is_stack_executable = parameters->options().is_stack_executable();
2436   else if (!this->input_with_gnu_stack_note_)
2437     return;
2438   else
2439     {
2440       if (this->input_requires_executable_stack_)
2441         is_stack_executable = true;
2442       else if (this->input_without_gnu_stack_note_)
2443         is_stack_executable =
2444           parameters->target().is_default_stack_executable();
2445       else
2446         is_stack_executable = false;
2447     }
2448
2449   if (parameters->options().relocatable())
2450     {
2451       const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
2452       elfcpp::Elf_Xword flags = 0;
2453       if (is_stack_executable)
2454         flags |= elfcpp::SHF_EXECINSTR;
2455       this->make_output_section(name, elfcpp::SHT_PROGBITS, flags,
2456                                 ORDER_INVALID, false);
2457     }
2458   else
2459     {
2460       if (this->script_options_->saw_phdrs_clause())
2461         return;
2462       int flags = elfcpp::PF_R | elfcpp::PF_W;
2463       if (is_stack_executable)
2464         flags |= elfcpp::PF_X;
2465       this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
2466     }
2467 }
2468
2469 // If --build-id was used, set up the build ID note.
2470
2471 void
2472 Layout::create_build_id()
2473 {
2474   if (!parameters->options().user_set_build_id())
2475     return;
2476
2477   const char* style = parameters->options().build_id();
2478   if (strcmp(style, "none") == 0)
2479     return;
2480
2481   // Set DESCSZ to the size of the note descriptor.  When possible,
2482   // set DESC to the note descriptor contents.
2483   size_t descsz;
2484   std::string desc;
2485   if (strcmp(style, "md5") == 0)
2486     descsz = 128 / 8;
2487   else if (strcmp(style, "sha1") == 0)
2488     descsz = 160 / 8;
2489   else if (strcmp(style, "uuid") == 0)
2490     {
2491       const size_t uuidsz = 128 / 8;
2492
2493       char buffer[uuidsz];
2494       memset(buffer, 0, uuidsz);
2495
2496       int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
2497       if (descriptor < 0)
2498         gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
2499                    strerror(errno));
2500       else
2501         {
2502           ssize_t got = ::read(descriptor, buffer, uuidsz);
2503           release_descriptor(descriptor, true);
2504           if (got < 0)
2505             gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
2506           else if (static_cast<size_t>(got) != uuidsz)
2507             gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
2508                        uuidsz, got);
2509         }
2510
2511       desc.assign(buffer, uuidsz);
2512       descsz = uuidsz;
2513     }
2514   else if (strncmp(style, "0x", 2) == 0)
2515     {
2516       hex_init();
2517       const char* p = style + 2;
2518       while (*p != '\0')
2519         {
2520           if (hex_p(p[0]) && hex_p(p[1]))
2521             {
2522               char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
2523               desc += c;
2524               p += 2;
2525             }
2526           else if (*p == '-' || *p == ':')
2527             ++p;
2528           else
2529             gold_fatal(_("--build-id argument '%s' not a valid hex number"),
2530                        style);
2531         }
2532       descsz = desc.size();
2533     }
2534   else
2535     gold_fatal(_("unrecognized --build-id argument '%s'"), style);
2536
2537   // Create the note.
2538   size_t trailing_padding;
2539   Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
2540                                          ".note.gnu.build-id", descsz, true,
2541                                          &trailing_padding);
2542   if (os == NULL)
2543     return;
2544
2545   if (!desc.empty())
2546     {
2547       // We know the value already, so we fill it in now.
2548       gold_assert(desc.size() == descsz);
2549
2550       Output_section_data* posd = new Output_data_const(desc, 4);
2551       os->add_output_section_data(posd);
2552
2553       if (trailing_padding != 0)
2554         {
2555           posd = new Output_data_zero_fill(trailing_padding, 0);
2556           os->add_output_section_data(posd);
2557         }
2558     }
2559   else
2560     {
2561       // We need to compute a checksum after we have completed the
2562       // link.
2563       gold_assert(trailing_padding == 0);
2564       this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
2565       os->add_output_section_data(this->build_id_note_);
2566     }
2567 }
2568
2569 // If we have both .stabXX and .stabXXstr sections, then the sh_link
2570 // field of the former should point to the latter.  I'm not sure who
2571 // started this, but the GNU linker does it, and some tools depend
2572 // upon it.
2573
2574 void
2575 Layout::link_stabs_sections()
2576 {
2577   if (!this->have_stabstr_section_)
2578     return;
2579
2580   for (Section_list::iterator p = this->section_list_.begin();
2581        p != this->section_list_.end();
2582        ++p)
2583     {
2584       if ((*p)->type() != elfcpp::SHT_STRTAB)
2585         continue;
2586
2587       const char* name = (*p)->name();
2588       if (strncmp(name, ".stab", 5) != 0)
2589         continue;
2590
2591       size_t len = strlen(name);
2592       if (strcmp(name + len - 3, "str") != 0)
2593         continue;
2594
2595       std::string stab_name(name, len - 3);
2596       Output_section* stab_sec;
2597       stab_sec = this->find_output_section(stab_name.c_str());
2598       if (stab_sec != NULL)
2599         stab_sec->set_link_section(*p);
2600     }
2601 }
2602
2603 // Create .gnu_incremental_inputs and related sections needed
2604 // for the next run of incremental linking to check what has changed.
2605
2606 void
2607 Layout::create_incremental_info_sections(Symbol_table* symtab)
2608 {
2609   Incremental_inputs* incr = this->incremental_inputs_;
2610
2611   gold_assert(incr != NULL);
2612
2613   // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
2614   incr->create_data_sections(symtab);
2615
2616   // Add the .gnu_incremental_inputs section.
2617   const char* incremental_inputs_name =
2618     this->namepool_.add(".gnu_incremental_inputs", false, NULL);
2619   Output_section* incremental_inputs_os =
2620     this->make_output_section(incremental_inputs_name,
2621                               elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0,
2622                               ORDER_INVALID, false);
2623   incremental_inputs_os->add_output_section_data(incr->inputs_section());
2624
2625   // Add the .gnu_incremental_symtab section.
2626   const char* incremental_symtab_name =
2627     this->namepool_.add(".gnu_incremental_symtab", false, NULL);
2628   Output_section* incremental_symtab_os =
2629     this->make_output_section(incremental_symtab_name,
2630                               elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0,
2631                               ORDER_INVALID, false);
2632   incremental_symtab_os->add_output_section_data(incr->symtab_section());
2633   incremental_symtab_os->set_entsize(4);
2634
2635   // Add the .gnu_incremental_relocs section.
2636   const char* incremental_relocs_name =
2637     this->namepool_.add(".gnu_incremental_relocs", false, NULL);
2638   Output_section* incremental_relocs_os =
2639     this->make_output_section(incremental_relocs_name,
2640                               elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0,
2641                               ORDER_INVALID, false);
2642   incremental_relocs_os->add_output_section_data(incr->relocs_section());
2643   incremental_relocs_os->set_entsize(incr->relocs_entsize());
2644
2645   // Add the .gnu_incremental_got_plt section.
2646   const char* incremental_got_plt_name =
2647     this->namepool_.add(".gnu_incremental_got_plt", false, NULL);
2648   Output_section* incremental_got_plt_os =
2649     this->make_output_section(incremental_got_plt_name,
2650                               elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0,
2651                               ORDER_INVALID, false);
2652   incremental_got_plt_os->add_output_section_data(incr->got_plt_section());
2653
2654   // Add the .gnu_incremental_strtab section.
2655   const char* incremental_strtab_name =
2656     this->namepool_.add(".gnu_incremental_strtab", false, NULL);
2657   Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name,
2658                                                         elfcpp::SHT_STRTAB, 0,
2659                                                         ORDER_INVALID, false);
2660   Output_data_strtab* strtab_data =
2661       new Output_data_strtab(incr->get_stringpool());
2662   incremental_strtab_os->add_output_section_data(strtab_data);
2663
2664   incremental_inputs_os->set_after_input_sections();
2665   incremental_symtab_os->set_after_input_sections();
2666   incremental_relocs_os->set_after_input_sections();
2667   incremental_got_plt_os->set_after_input_sections();
2668
2669   incremental_inputs_os->set_link_section(incremental_strtab_os);
2670   incremental_symtab_os->set_link_section(incremental_inputs_os);
2671   incremental_relocs_os->set_link_section(incremental_inputs_os);
2672   incremental_got_plt_os->set_link_section(incremental_inputs_os);
2673 }
2674
2675 // Return whether SEG1 should be before SEG2 in the output file.  This
2676 // is based entirely on the segment type and flags.  When this is
2677 // called the segment addresses has normally not yet been set.
2678
2679 bool
2680 Layout::segment_precedes(const Output_segment* seg1,
2681                          const Output_segment* seg2)
2682 {
2683   elfcpp::Elf_Word type1 = seg1->type();
2684   elfcpp::Elf_Word type2 = seg2->type();
2685
2686   // The single PT_PHDR segment is required to precede any loadable
2687   // segment.  We simply make it always first.
2688   if (type1 == elfcpp::PT_PHDR)
2689     {
2690       gold_assert(type2 != elfcpp::PT_PHDR);
2691       return true;
2692     }
2693   if (type2 == elfcpp::PT_PHDR)
2694     return false;
2695
2696   // The single PT_INTERP segment is required to precede any loadable
2697   // segment.  We simply make it always second.
2698   if (type1 == elfcpp::PT_INTERP)
2699     {
2700       gold_assert(type2 != elfcpp::PT_INTERP);
2701       return true;
2702     }
2703   if (type2 == elfcpp::PT_INTERP)
2704     return false;
2705
2706   // We then put PT_LOAD segments before any other segments.
2707   if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
2708     return true;
2709   if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
2710     return false;
2711
2712   // We put the PT_TLS segment last except for the PT_GNU_RELRO
2713   // segment, because that is where the dynamic linker expects to find
2714   // it (this is just for efficiency; other positions would also work
2715   // correctly).
2716   if (type1 == elfcpp::PT_TLS
2717       && type2 != elfcpp::PT_TLS
2718       && type2 != elfcpp::PT_GNU_RELRO)
2719     return false;
2720   if (type2 == elfcpp::PT_TLS
2721       && type1 != elfcpp::PT_TLS
2722       && type1 != elfcpp::PT_GNU_RELRO)
2723     return true;
2724
2725   // We put the PT_GNU_RELRO segment last, because that is where the
2726   // dynamic linker expects to find it (as with PT_TLS, this is just
2727   // for efficiency).
2728   if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
2729     return false;
2730   if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
2731     return true;
2732
2733   const elfcpp::Elf_Word flags1 = seg1->flags();
2734   const elfcpp::Elf_Word flags2 = seg2->flags();
2735
2736   // The order of non-PT_LOAD segments is unimportant.  We simply sort
2737   // by the numeric segment type and flags values.  There should not
2738   // be more than one segment with the same type and flags.
2739   if (type1 != elfcpp::PT_LOAD)
2740     {
2741       if (type1 != type2)
2742         return type1 < type2;
2743       gold_assert(flags1 != flags2);
2744       return flags1 < flags2;
2745     }
2746
2747   // If the addresses are set already, sort by load address.
2748   if (seg1->are_addresses_set())
2749     {
2750       if (!seg2->are_addresses_set())
2751         return true;
2752
2753       unsigned int section_count1 = seg1->output_section_count();
2754       unsigned int section_count2 = seg2->output_section_count();
2755       if (section_count1 == 0 && section_count2 > 0)
2756         return true;
2757       if (section_count1 > 0 && section_count2 == 0)
2758         return false;
2759
2760       uint64_t paddr1 = (seg1->are_addresses_set()
2761                          ? seg1->paddr()
2762                          : seg1->first_section_load_address());
2763       uint64_t paddr2 = (seg2->are_addresses_set()
2764                          ? seg2->paddr()
2765                          : seg2->first_section_load_address());
2766
2767       if (paddr1 != paddr2)
2768         return paddr1 < paddr2;
2769     }
2770   else if (seg2->are_addresses_set())
2771     return false;
2772
2773   // A segment which holds large data comes after a segment which does
2774   // not hold large data.
2775   if (seg1->is_large_data_segment())
2776     {
2777       if (!seg2->is_large_data_segment())
2778         return false;
2779     }
2780   else if (seg2->is_large_data_segment())
2781     return true;
2782
2783   // Otherwise, we sort PT_LOAD segments based on the flags.  Readonly
2784   // segments come before writable segments.  Then writable segments
2785   // with data come before writable segments without data.  Then
2786   // executable segments come before non-executable segments.  Then
2787   // the unlikely case of a non-readable segment comes before the
2788   // normal case of a readable segment.  If there are multiple
2789   // segments with the same type and flags, we require that the
2790   // address be set, and we sort by virtual address and then physical
2791   // address.
2792   if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
2793     return (flags1 & elfcpp::PF_W) == 0;
2794   if ((flags1 & elfcpp::PF_W) != 0
2795       && seg1->has_any_data_sections() != seg2->has_any_data_sections())
2796     return seg1->has_any_data_sections();
2797   if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
2798     return (flags1 & elfcpp::PF_X) != 0;
2799   if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
2800     return (flags1 & elfcpp::PF_R) == 0;
2801
2802   // We shouldn't get here--we shouldn't create segments which we
2803   // can't distinguish.
2804   gold_unreachable();
2805 }
2806
2807 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
2808
2809 static off_t
2810 align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
2811 {
2812   uint64_t unsigned_off = off;
2813   uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
2814                           | (addr & (abi_pagesize - 1)));
2815   if (aligned_off < unsigned_off)
2816     aligned_off += abi_pagesize;
2817   return aligned_off;
2818 }
2819
2820 // Set the file offsets of all the segments, and all the sections they
2821 // contain.  They have all been created.  LOAD_SEG must be be laid out
2822 // first.  Return the offset of the data to follow.
2823
2824 off_t
2825 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
2826                             unsigned int* pshndx)
2827 {
2828   // Sort them into the final order.
2829   std::sort(this->segment_list_.begin(), this->segment_list_.end(),
2830             Layout::Compare_segments());
2831
2832   // Find the PT_LOAD segments, and set their addresses and offsets
2833   // and their section's addresses and offsets.
2834   uint64_t addr;
2835   if (parameters->options().user_set_Ttext())
2836     addr = parameters->options().Ttext();
2837   else if (parameters->options().output_is_position_independent())
2838     addr = 0;
2839   else
2840     addr = target->default_text_segment_address();
2841   off_t off = 0;
2842
2843   // If LOAD_SEG is NULL, then the file header and segment headers
2844   // will not be loadable.  But they still need to be at offset 0 in
2845   // the file.  Set their offsets now.
2846   if (load_seg == NULL)
2847     {
2848       for (Data_list::iterator p = this->special_output_list_.begin();
2849            p != this->special_output_list_.end();
2850            ++p)
2851         {
2852           off = align_address(off, (*p)->addralign());
2853           (*p)->set_address_and_file_offset(0, off);
2854           off += (*p)->data_size();
2855         }
2856     }
2857
2858   unsigned int increase_relro = this->increase_relro_;
2859   if (this->script_options_->saw_sections_clause())
2860     increase_relro = 0;
2861
2862   const bool check_sections = parameters->options().check_sections();
2863   Output_segment* last_load_segment = NULL;
2864
2865   for (Segment_list::iterator p = this->segment_list_.begin();
2866        p != this->segment_list_.end();
2867        ++p)
2868     {
2869       if ((*p)->type() == elfcpp::PT_LOAD)
2870         {
2871           if (load_seg != NULL && load_seg != *p)
2872             gold_unreachable();
2873           load_seg = NULL;
2874
2875           bool are_addresses_set = (*p)->are_addresses_set();
2876           if (are_addresses_set)
2877             {
2878               // When it comes to setting file offsets, we care about
2879               // the physical address.
2880               addr = (*p)->paddr();
2881             }
2882           else if (parameters->options().user_set_Tdata()
2883                    && ((*p)->flags() & elfcpp::PF_W) != 0
2884                    && (!parameters->options().user_set_Tbss()
2885                        || (*p)->has_any_data_sections()))
2886             {
2887               addr = parameters->options().Tdata();
2888               are_addresses_set = true;
2889             }
2890           else if (parameters->options().user_set_Tbss()
2891                    && ((*p)->flags() & elfcpp::PF_W) != 0
2892                    && !(*p)->has_any_data_sections())
2893             {
2894               addr = parameters->options().Tbss();
2895               are_addresses_set = true;
2896             }
2897
2898           uint64_t orig_addr = addr;
2899           uint64_t orig_off = off;
2900
2901           uint64_t aligned_addr = 0;
2902           uint64_t abi_pagesize = target->abi_pagesize();
2903           uint64_t common_pagesize = target->common_pagesize();
2904
2905           if (!parameters->options().nmagic()
2906               && !parameters->options().omagic())
2907             (*p)->set_minimum_p_align(common_pagesize);
2908
2909           if (!are_addresses_set)
2910             {
2911               // Skip the address forward one page, maintaining the same
2912               // position within the page.  This lets us store both segments
2913               // overlapping on a single page in the file, but the loader will
2914               // put them on different pages in memory. We will revisit this
2915               // decision once we know the size of the segment.
2916
2917               addr = align_address(addr, (*p)->maximum_alignment());
2918               aligned_addr = addr;
2919
2920               if ((addr & (abi_pagesize - 1)) != 0)
2921                 addr = addr + abi_pagesize;
2922
2923               off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
2924             }
2925
2926           if (!parameters->options().nmagic()
2927               && !parameters->options().omagic())
2928             off = align_file_offset(off, addr, abi_pagesize);
2929           else if (load_seg == NULL)
2930             {
2931               // This is -N or -n with a section script which prevents
2932               // us from using a load segment.  We need to ensure that
2933               // the file offset is aligned to the alignment of the
2934               // segment.  This is because the linker script
2935               // implicitly assumed a zero offset.  If we don't align
2936               // here, then the alignment of the sections in the
2937               // linker script may not match the alignment of the
2938               // sections in the set_section_addresses call below,
2939               // causing an error about dot moving backward.
2940               off = align_address(off, (*p)->maximum_alignment());
2941             }
2942
2943           unsigned int shndx_hold = *pshndx;
2944           bool has_relro = false;
2945           uint64_t new_addr = (*p)->set_section_addresses(this, false, addr,
2946                                                           &increase_relro,
2947                                                           &has_relro,
2948                                                           &off, pshndx);
2949
2950           // Now that we know the size of this segment, we may be able
2951           // to save a page in memory, at the cost of wasting some
2952           // file space, by instead aligning to the start of a new
2953           // page.  Here we use the real machine page size rather than
2954           // the ABI mandated page size.  If the segment has been
2955           // aligned so that the relro data ends at a page boundary,
2956           // we do not try to realign it.
2957
2958           if (!are_addresses_set
2959               && !has_relro
2960               && aligned_addr != addr
2961               && !parameters->incremental_update())
2962             {
2963               uint64_t first_off = (common_pagesize
2964                                     - (aligned_addr
2965                                        & (common_pagesize - 1)));
2966               uint64_t last_off = new_addr & (common_pagesize - 1);
2967               if (first_off > 0
2968                   && last_off > 0
2969                   && ((aligned_addr & ~ (common_pagesize - 1))
2970                       != (new_addr & ~ (common_pagesize - 1)))
2971                   && first_off + last_off <= common_pagesize)
2972                 {
2973                   *pshndx = shndx_hold;
2974                   addr = align_address(aligned_addr, common_pagesize);
2975                   addr = align_address(addr, (*p)->maximum_alignment());
2976                   off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
2977                   off = align_file_offset(off, addr, abi_pagesize);
2978
2979                   increase_relro = this->increase_relro_;
2980                   if (this->script_options_->saw_sections_clause())
2981                     increase_relro = 0;
2982                   has_relro = false;
2983
2984                   new_addr = (*p)->set_section_addresses(this, true, addr,
2985                                                          &increase_relro,
2986                                                          &has_relro,
2987                                                          &off, pshndx);
2988                 }
2989             }
2990
2991           addr = new_addr;
2992
2993           // Implement --check-sections.  We know that the segments
2994           // are sorted by LMA.
2995           if (check_sections && last_load_segment != NULL)
2996             {
2997               gold_assert(last_load_segment->paddr() <= (*p)->paddr());
2998               if (last_load_segment->paddr() + last_load_segment->memsz()
2999                   > (*p)->paddr())
3000                 {
3001                   unsigned long long lb1 = last_load_segment->paddr();
3002                   unsigned long long le1 = lb1 + last_load_segment->memsz();
3003                   unsigned long long lb2 = (*p)->paddr();
3004                   unsigned long long le2 = lb2 + (*p)->memsz();
3005                   gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3006                                "[0x%llx -> 0x%llx]"),
3007                              lb1, le1, lb2, le2);
3008                 }
3009             }
3010           last_load_segment = *p;
3011         }
3012     }
3013
3014   // Handle the non-PT_LOAD segments, setting their offsets from their
3015   // section's offsets.
3016   for (Segment_list::iterator p = this->segment_list_.begin();
3017        p != this->segment_list_.end();
3018        ++p)
3019     {
3020       if ((*p)->type() != elfcpp::PT_LOAD)
3021         (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO
3022                          ? increase_relro
3023                          : 0);
3024     }
3025
3026   // Set the TLS offsets for each section in the PT_TLS segment.
3027   if (this->tls_segment_ != NULL)
3028     this->tls_segment_->set_tls_offsets();
3029
3030   return off;
3031 }
3032
3033 // Set the offsets of all the allocated sections when doing a
3034 // relocatable link.  This does the same jobs as set_segment_offsets,
3035 // only for a relocatable link.
3036
3037 off_t
3038 Layout::set_relocatable_section_offsets(Output_data* file_header,
3039                                         unsigned int* pshndx)
3040 {
3041   off_t off = 0;
3042
3043   file_header->set_address_and_file_offset(0, 0);
3044   off += file_header->data_size();
3045
3046   for (Section_list::iterator p = this->section_list_.begin();
3047        p != this->section_list_.end();
3048        ++p)
3049     {
3050       // We skip unallocated sections here, except that group sections
3051       // have to come first.
3052       if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
3053           && (*p)->type() != elfcpp::SHT_GROUP)
3054         continue;
3055
3056       off = align_address(off, (*p)->addralign());
3057
3058       // The linker script might have set the address.
3059       if (!(*p)->is_address_valid())
3060         (*p)->set_address(0);
3061       (*p)->set_file_offset(off);
3062       (*p)->finalize_data_size();
3063       off += (*p)->data_size();
3064
3065       (*p)->set_out_shndx(*pshndx);
3066       ++*pshndx;
3067     }
3068
3069   return off;
3070 }
3071
3072 // Set the file offset of all the sections not associated with a
3073 // segment.
3074
3075 off_t
3076 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
3077 {
3078   off_t startoff = off;
3079   off_t maxoff = off;
3080
3081   for (Section_list::iterator p = this->unattached_section_list_.begin();
3082        p != this->unattached_section_list_.end();
3083        ++p)
3084     {
3085       // The symtab section is handled in create_symtab_sections.
3086       if (*p == this->symtab_section_)
3087         continue;
3088
3089       // If we've already set the data size, don't set it again.
3090       if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
3091         continue;
3092
3093       if (pass == BEFORE_INPUT_SECTIONS_PASS
3094           && (*p)->requires_postprocessing())
3095         {
3096           (*p)->create_postprocessing_buffer();
3097           this->any_postprocessing_sections_ = true;
3098         }
3099
3100       if (pass == BEFORE_INPUT_SECTIONS_PASS
3101           && (*p)->after_input_sections())
3102         continue;
3103       else if (pass == POSTPROCESSING_SECTIONS_PASS
3104                && (!(*p)->after_input_sections()
3105                    || (*p)->type() == elfcpp::SHT_STRTAB))
3106         continue;
3107       else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3108                && (!(*p)->after_input_sections()
3109                    || (*p)->type() != elfcpp::SHT_STRTAB))
3110         continue;
3111
3112       if (!parameters->incremental_update())
3113         {
3114           off = align_address(off, (*p)->addralign());
3115           (*p)->set_file_offset(off);
3116           (*p)->finalize_data_size();
3117         }
3118       else
3119         {
3120           // Incremental update: allocate file space from free list.
3121           (*p)->pre_finalize_data_size();
3122           off_t current_size = (*p)->current_data_size();
3123           off = this->allocate(current_size, (*p)->addralign(), startoff);
3124           if (off == -1)
3125             {
3126               if (is_debugging_enabled(DEBUG_INCREMENTAL))
3127                 this->free_list_.dump();
3128               gold_assert((*p)->output_section() != NULL);
3129               gold_fatal(_("out of patch space for section %s; "
3130                            "relink with --incremental-full"),
3131                          (*p)->output_section()->name());
3132             }
3133           (*p)->set_file_offset(off);
3134           (*p)->finalize_data_size();
3135           if ((*p)->data_size() > current_size)
3136             {
3137               gold_assert((*p)->output_section() != NULL);
3138               gold_fatal(_("%s: section changed size; "
3139                            "relink with --incremental-full"),
3140                          (*p)->output_section()->name());
3141             }
3142           gold_debug(DEBUG_INCREMENTAL,
3143                      "set_section_offsets: %08lx %08lx %s",
3144                      static_cast<long>(off),
3145                      static_cast<long>((*p)->data_size()),
3146                      ((*p)->output_section() != NULL
3147                       ? (*p)->output_section()->name() : "(special)"));
3148         }
3149
3150       off += (*p)->data_size();
3151       if (off > maxoff)
3152         maxoff = off;
3153
3154       // At this point the name must be set.
3155       if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
3156         this->namepool_.add((*p)->name(), false, NULL);
3157     }
3158   return maxoff;
3159 }
3160
3161 // Set the section indexes of all the sections not associated with a
3162 // segment.
3163
3164 unsigned int
3165 Layout::set_section_indexes(unsigned int shndx)
3166 {
3167   for (Section_list::iterator p = this->unattached_section_list_.begin();
3168        p != this->unattached_section_list_.end();
3169        ++p)
3170     {
3171       if (!(*p)->has_out_shndx())
3172         {
3173           (*p)->set_out_shndx(shndx);
3174           ++shndx;
3175         }
3176     }
3177   return shndx;
3178 }
3179
3180 // Set the section addresses according to the linker script.  This is
3181 // only called when we see a SECTIONS clause.  This returns the
3182 // program segment which should hold the file header and segment
3183 // headers, if any.  It will return NULL if they should not be in a
3184 // segment.
3185
3186 Output_segment*
3187 Layout::set_section_addresses_from_script(Symbol_table* symtab)
3188 {
3189   Script_sections* ss = this->script_options_->script_sections();
3190   gold_assert(ss->saw_sections_clause());
3191   return this->script_options_->set_section_addresses(symtab, this);
3192 }
3193
3194 // Place the orphan sections in the linker script.
3195
3196 void
3197 Layout::place_orphan_sections_in_script()
3198 {
3199   Script_sections* ss = this->script_options_->script_sections();
3200   gold_assert(ss->saw_sections_clause());
3201
3202   // Place each orphaned output section in the script.
3203   for (Section_list::iterator p = this->section_list_.begin();
3204        p != this->section_list_.end();
3205        ++p)
3206     {
3207       if (!(*p)->found_in_sections_clause())
3208         ss->place_orphan(*p);
3209     }
3210 }
3211
3212 // Count the local symbols in the regular symbol table and the dynamic
3213 // symbol table, and build the respective string pools.
3214
3215 void
3216 Layout::count_local_symbols(const Task* task,
3217                             const Input_objects* input_objects)
3218 {
3219   // First, figure out an upper bound on the number of symbols we'll
3220   // be inserting into each pool.  This helps us create the pools with
3221   // the right size, to avoid unnecessary hashtable resizing.
3222   unsigned int symbol_count = 0;
3223   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3224        p != input_objects->relobj_end();
3225        ++p)
3226     symbol_count += (*p)->local_symbol_count();
3227
3228   // Go from "upper bound" to "estimate."  We overcount for two
3229   // reasons: we double-count symbols that occur in more than one
3230   // object file, and we count symbols that are dropped from the
3231   // output.  Add it all together and assume we overcount by 100%.
3232   symbol_count /= 2;
3233
3234   // We assume all symbols will go into both the sympool and dynpool.
3235   this->sympool_.reserve(symbol_count);
3236   this->dynpool_.reserve(symbol_count);
3237
3238   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3239        p != input_objects->relobj_end();
3240        ++p)
3241     {
3242       Task_lock_obj<Object> tlo(task, *p);
3243       (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
3244     }
3245 }
3246
3247 // Create the symbol table sections.  Here we also set the final
3248 // values of the symbols.  At this point all the loadable sections are
3249 // fully laid out.  SHNUM is the number of sections so far.
3250
3251 void
3252 Layout::create_symtab_sections(const Input_objects* input_objects,
3253                                Symbol_table* symtab,
3254                                unsigned int shnum,
3255                                off_t* poff)
3256 {
3257   int symsize;
3258   unsigned int align;
3259   if (parameters->target().get_size() == 32)
3260     {
3261       symsize = elfcpp::Elf_sizes<32>::sym_size;
3262       align = 4;
3263     }
3264   else if (parameters->target().get_size() == 64)
3265     {
3266       symsize = elfcpp::Elf_sizes<64>::sym_size;
3267       align = 8;
3268     }
3269   else
3270     gold_unreachable();
3271
3272   // Compute file offsets relative to the start of the symtab section.
3273   off_t off = 0;
3274
3275   // Save space for the dummy symbol at the start of the section.  We
3276   // never bother to write this out--it will just be left as zero.
3277   off += symsize;
3278   unsigned int local_symbol_index = 1;
3279
3280   // Add STT_SECTION symbols for each Output section which needs one.
3281   for (Section_list::iterator p = this->section_list_.begin();
3282        p != this->section_list_.end();
3283        ++p)
3284     {
3285       if (!(*p)->needs_symtab_index())
3286         (*p)->set_symtab_index(-1U);
3287       else
3288         {
3289           (*p)->set_symtab_index(local_symbol_index);
3290           ++local_symbol_index;
3291           off += symsize;
3292         }
3293     }
3294
3295   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3296        p != input_objects->relobj_end();
3297        ++p)
3298     {
3299       unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
3300                                                         off, symtab);
3301       off += (index - local_symbol_index) * symsize;
3302       local_symbol_index = index;
3303     }
3304
3305   unsigned int local_symcount = local_symbol_index;
3306   gold_assert(static_cast<off_t>(local_symcount * symsize) == off);
3307
3308   off_t dynoff;
3309   size_t dyn_global_index;
3310   size_t dyncount;
3311   if (this->dynsym_section_ == NULL)
3312     {
3313       dynoff = 0;
3314       dyn_global_index = 0;
3315       dyncount = 0;
3316     }
3317   else
3318     {
3319       dyn_global_index = this->dynsym_section_->info();
3320       off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
3321       dynoff = this->dynsym_section_->offset() + locsize;
3322       dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
3323       gold_assert(static_cast<off_t>(dyncount * symsize)
3324                   == this->dynsym_section_->data_size() - locsize);
3325     }
3326
3327   off_t global_off = off;
3328   off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
3329                          &this->sympool_, &local_symcount);
3330
3331   if (!parameters->options().strip_all())
3332     {
3333       this->sympool_.set_string_offsets();
3334
3335       const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
3336       Output_section* osymtab = this->make_output_section(symtab_name,
3337                                                           elfcpp::SHT_SYMTAB,
3338                                                           0, ORDER_INVALID,
3339                                                           false);
3340       this->symtab_section_ = osymtab;
3341
3342       Output_section_data* pos = new Output_data_fixed_space(off, align,
3343                                                              "** symtab");
3344       osymtab->add_output_section_data(pos);
3345
3346       // We generate a .symtab_shndx section if we have more than
3347       // SHN_LORESERVE sections.  Technically it is possible that we
3348       // don't need one, because it is possible that there are no
3349       // symbols in any of sections with indexes larger than
3350       // SHN_LORESERVE.  That is probably unusual, though, and it is
3351       // easier to always create one than to compute section indexes
3352       // twice (once here, once when writing out the symbols).
3353       if (shnum >= elfcpp::SHN_LORESERVE)
3354         {
3355           const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
3356                                                                false, NULL);
3357           Output_section* osymtab_xindex =
3358             this->make_output_section(symtab_xindex_name,
3359                                       elfcpp::SHT_SYMTAB_SHNDX, 0,
3360                                       ORDER_INVALID, false);
3361
3362           size_t symcount = off / symsize;
3363           this->symtab_xindex_ = new Output_symtab_xindex(symcount);
3364
3365           osymtab_xindex->add_output_section_data(this->symtab_xindex_);
3366
3367           osymtab_xindex->set_link_section(osymtab);
3368           osymtab_xindex->set_addralign(4);
3369           osymtab_xindex->set_entsize(4);
3370
3371           osymtab_xindex->set_after_input_sections();
3372
3373           // This tells the driver code to wait until the symbol table
3374           // has written out before writing out the postprocessing
3375           // sections, including the .symtab_shndx section.
3376           this->any_postprocessing_sections_ = true;
3377         }
3378
3379       const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
3380       Output_section* ostrtab = this->make_output_section(strtab_name,
3381                                                           elfcpp::SHT_STRTAB,
3382                                                           0, ORDER_INVALID,
3383                                                           false);
3384
3385       Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
3386       ostrtab->add_output_section_data(pstr);
3387
3388       off_t symtab_off;
3389       if (!parameters->incremental_update())
3390         symtab_off = align_address(*poff, align);
3391       else
3392         {
3393           symtab_off = this->allocate(off, align, *poff);
3394           if (off == -1)
3395             gold_fatal(_("out of patch space for symbol table; "
3396                          "relink with --incremental-full"));
3397           gold_debug(DEBUG_INCREMENTAL,
3398                      "create_symtab_sections: %08lx %08lx .symtab",
3399                      static_cast<long>(symtab_off),
3400                      static_cast<long>(off));
3401         }
3402
3403       symtab->set_file_offset(symtab_off + global_off);
3404       osymtab->set_file_offset(symtab_off);
3405       osymtab->finalize_data_size();
3406       osymtab->set_link_section(ostrtab);
3407       osymtab->set_info(local_symcount);
3408       osymtab->set_entsize(symsize);
3409
3410       if (symtab_off + off > *poff)
3411         *poff = symtab_off + off;
3412     }
3413 }
3414
3415 // Create the .shstrtab section, which holds the names of the
3416 // sections.  At the time this is called, we have created all the
3417 // output sections except .shstrtab itself.
3418
3419 Output_section*
3420 Layout::create_shstrtab()
3421 {
3422   // FIXME: We don't need to create a .shstrtab section if we are
3423   // stripping everything.
3424
3425   const char* name = this->namepool_.add(".shstrtab", false, NULL);
3426
3427   Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0,
3428                                                  ORDER_INVALID, false);
3429
3430   if (strcmp(parameters->options().compress_debug_sections(), "none") != 0)
3431     {
3432       // We can't write out this section until we've set all the
3433       // section names, and we don't set the names of compressed
3434       // output sections until relocations are complete.  FIXME: With
3435       // the current names we use, this is unnecessary.
3436       os->set_after_input_sections();
3437     }
3438
3439   Output_section_data* posd = new Output_data_strtab(&this->namepool_);
3440   os->add_output_section_data(posd);
3441
3442   return os;
3443 }
3444
3445 // Create the section headers.  SIZE is 32 or 64.  OFF is the file
3446 // offset.
3447
3448 void
3449 Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
3450 {
3451   Output_section_headers* oshdrs;
3452   oshdrs = new Output_section_headers(this,
3453                                       &this->segment_list_,
3454                                       &this->section_list_,
3455                                       &this->unattached_section_list_,
3456                                       &this->namepool_,
3457                                       shstrtab_section);
3458   off_t off;
3459   if (!parameters->incremental_update())
3460     off = align_address(*poff, oshdrs->addralign());
3461   else
3462     {
3463       oshdrs->pre_finalize_data_size();
3464       off = this->allocate(oshdrs->data_size(), oshdrs->addralign(), *poff);
3465       if (off == -1)
3466           gold_fatal(_("out of patch space for section header table; "
3467                        "relink with --incremental-full"));
3468       gold_debug(DEBUG_INCREMENTAL,
3469                  "create_shdrs: %08lx %08lx (section header table)",
3470                  static_cast<long>(off),
3471                  static_cast<long>(off + oshdrs->data_size()));
3472     }
3473   oshdrs->set_address_and_file_offset(0, off);
3474   off += oshdrs->data_size();
3475   if (off > *poff)
3476     *poff = off;
3477   this->section_headers_ = oshdrs;
3478 }
3479
3480 // Count the allocated sections.
3481
3482 size_t
3483 Layout::allocated_output_section_count() const
3484 {
3485   size_t section_count = 0;
3486   for (Segment_list::const_iterator p = this->segment_list_.begin();
3487        p != this->segment_list_.end();
3488        ++p)
3489     section_count += (*p)->output_section_count();
3490   return section_count;
3491 }
3492
3493 // Create the dynamic symbol table.
3494
3495 void
3496 Layout::create_dynamic_symtab(const Input_objects* input_objects,
3497                               Symbol_table* symtab,
3498                               Output_section** pdynstr,
3499                               unsigned int* plocal_dynamic_count,
3500                               std::vector<Symbol*>* pdynamic_symbols,
3501                               Versions* pversions)
3502 {
3503   // Count all the symbols in the dynamic symbol table, and set the
3504   // dynamic symbol indexes.
3505
3506   // Skip symbol 0, which is always all zeroes.
3507   unsigned int index = 1;
3508
3509   // Add STT_SECTION symbols for each Output section which needs one.
3510   for (Section_list::iterator p = this->section_list_.begin();
3511        p != this->section_list_.end();
3512        ++p)
3513     {
3514       if (!(*p)->needs_dynsym_index())
3515         (*p)->set_dynsym_index(-1U);
3516       else
3517         {
3518           (*p)->set_dynsym_index(index);
3519           ++index;
3520         }
3521     }
3522
3523   // Count the local symbols that need to go in the dynamic symbol table,
3524   // and set the dynamic symbol indexes.
3525   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3526        p != input_objects->relobj_end();
3527        ++p)
3528     {
3529       unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
3530       index = new_index;
3531     }
3532
3533   unsigned int local_symcount = index;
3534   *plocal_dynamic_count = local_symcount;
3535
3536   index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
3537                                      &this->dynpool_, pversions);
3538
3539   int symsize;
3540   unsigned int align;
3541   const int size = parameters->target().get_size();
3542   if (size == 32)
3543     {
3544       symsize = elfcpp::Elf_sizes<32>::sym_size;
3545       align = 4;
3546     }
3547   else if (size == 64)
3548     {
3549       symsize = elfcpp::Elf_sizes<64>::sym_size;
3550       align = 8;
3551     }
3552   else
3553     gold_unreachable();
3554
3555   // Create the dynamic symbol table section.
3556
3557   Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
3558                                                        elfcpp::SHT_DYNSYM,
3559                                                        elfcpp::SHF_ALLOC,
3560                                                        false,
3561                                                        ORDER_DYNAMIC_LINKER,
3562                                                        false);
3563
3564   Output_section_data* odata = new Output_data_fixed_space(index * symsize,
3565                                                            align,
3566                                                            "** dynsym");
3567   dynsym->add_output_section_data(odata);
3568
3569   dynsym->set_info(local_symcount);
3570   dynsym->set_entsize(symsize);
3571   dynsym->set_addralign(align);
3572
3573   this->dynsym_section_ = dynsym;
3574
3575   Output_data_dynamic* const odyn = this->dynamic_data_;
3576   odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
3577   odyn->add_constant(elfcpp::DT_SYMENT, symsize);
3578
3579   // If there are more than SHN_LORESERVE allocated sections, we
3580   // create a .dynsym_shndx section.  It is possible that we don't
3581   // need one, because it is possible that there are no dynamic
3582   // symbols in any of the sections with indexes larger than
3583   // SHN_LORESERVE.  This is probably unusual, though, and at this
3584   // time we don't know the actual section indexes so it is
3585   // inconvenient to check.
3586   if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
3587     {
3588       Output_section* dynsym_xindex =
3589         this->choose_output_section(NULL, ".dynsym_shndx",
3590                                     elfcpp::SHT_SYMTAB_SHNDX,
3591                                     elfcpp::SHF_ALLOC,
3592                                     false, ORDER_DYNAMIC_LINKER, false);
3593
3594       this->dynsym_xindex_ = new Output_symtab_xindex(index);
3595
3596       dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
3597
3598       dynsym_xindex->set_link_section(dynsym);
3599       dynsym_xindex->set_addralign(4);
3600       dynsym_xindex->set_entsize(4);
3601
3602       dynsym_xindex->set_after_input_sections();
3603
3604       // This tells the driver code to wait until the symbol table has
3605       // written out before writing out the postprocessing sections,
3606       // including the .dynsym_shndx section.
3607       this->any_postprocessing_sections_ = true;
3608     }
3609
3610   // Create the dynamic string table section.
3611
3612   Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
3613                                                        elfcpp::SHT_STRTAB,
3614                                                        elfcpp::SHF_ALLOC,
3615                                                        false,
3616                                                        ORDER_DYNAMIC_LINKER,
3617                                                        false);
3618
3619   Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
3620   dynstr->add_output_section_data(strdata);
3621
3622   dynsym->set_link_section(dynstr);
3623   this->dynamic_section_->set_link_section(dynstr);
3624
3625   odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
3626   odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
3627
3628   *pdynstr = dynstr;
3629
3630   // Create the hash tables.
3631
3632   if (strcmp(parameters->options().hash_style(), "sysv") == 0
3633       || strcmp(parameters->options().hash_style(), "both") == 0)
3634     {
3635       unsigned char* phash;
3636       unsigned int hashlen;
3637       Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
3638                                     &phash, &hashlen);
3639
3640       Output_section* hashsec =
3641         this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH,
3642                                     elfcpp::SHF_ALLOC, false,
3643                                     ORDER_DYNAMIC_LINKER, false);
3644
3645       Output_section_data* hashdata = new Output_data_const_buffer(phash,
3646                                                                    hashlen,
3647                                                                    align,
3648                                                                    "** hash");
3649       hashsec->add_output_section_data(hashdata);
3650
3651       hashsec->set_link_section(dynsym);
3652       hashsec->set_entsize(4);
3653
3654       odyn->add_section_address(elfcpp::DT_HASH, hashsec);
3655     }
3656
3657   if (strcmp(parameters->options().hash_style(), "gnu") == 0
3658       || strcmp(parameters->options().hash_style(), "both") == 0)
3659     {
3660       unsigned char* phash;
3661       unsigned int hashlen;
3662       Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
3663                                     &phash, &hashlen);
3664
3665       Output_section* hashsec =
3666         this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH,
3667                                     elfcpp::SHF_ALLOC, false,
3668                                     ORDER_DYNAMIC_LINKER, false);
3669
3670       Output_section_data* hashdata = new Output_data_const_buffer(phash,
3671                                                                    hashlen,
3672                                                                    align,
3673                                                                    "** hash");
3674       hashsec->add_output_section_data(hashdata);
3675
3676       hashsec->set_link_section(dynsym);
3677
3678       // For a 64-bit target, the entries in .gnu.hash do not have a
3679       // uniform size, so we only set the entry size for a 32-bit
3680       // target.
3681       if (parameters->target().get_size() == 32)
3682         hashsec->set_entsize(4);
3683
3684       odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
3685     }
3686 }
3687
3688 // Assign offsets to each local portion of the dynamic symbol table.
3689
3690 void
3691 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
3692 {
3693   Output_section* dynsym = this->dynsym_section_;
3694   gold_assert(dynsym != NULL);
3695
3696   off_t off = dynsym->offset();
3697
3698   // Skip the dummy symbol at the start of the section.
3699   off += dynsym->entsize();
3700
3701   for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3702        p != input_objects->relobj_end();
3703        ++p)
3704     {
3705       unsigned int count = (*p)->set_local_dynsym_offset(off);
3706       off += count * dynsym->entsize();
3707     }
3708 }
3709
3710 // Create the version sections.
3711
3712 void
3713 Layout::create_version_sections(const Versions* versions,
3714                                 const Symbol_table* symtab,
3715                                 unsigned int local_symcount,
3716                                 const std::vector<Symbol*>& dynamic_symbols,
3717                                 const Output_section* dynstr)
3718 {
3719   if (!versions->any_defs() && !versions->any_needs())
3720     return;
3721
3722   switch (parameters->size_and_endianness())
3723     {
3724 #ifdef HAVE_TARGET_32_LITTLE
3725     case Parameters::TARGET_32_LITTLE:
3726       this->sized_create_version_sections<32, false>(versions, symtab,
3727                                                      local_symcount,
3728                                                      dynamic_symbols, dynstr);
3729       break;
3730 #endif
3731 #ifdef HAVE_TARGET_32_BIG
3732     case Parameters::TARGET_32_BIG:
3733       this->sized_create_version_sections<32, true>(versions, symtab,
3734                                                     local_symcount,
3735                                                     dynamic_symbols, dynstr);
3736       break;
3737 #endif
3738 #ifdef HAVE_TARGET_64_LITTLE
3739     case Parameters::TARGET_64_LITTLE:
3740       this->sized_create_version_sections<64, false>(versions, symtab,
3741                                                      local_symcount,
3742                                                      dynamic_symbols, dynstr);
3743       break;
3744 #endif
3745 #ifdef HAVE_TARGET_64_BIG
3746     case Parameters::TARGET_64_BIG:
3747       this->sized_create_version_sections<64, true>(versions, symtab,
3748                                                     local_symcount,
3749                                                     dynamic_symbols, dynstr);
3750       break;
3751 #endif
3752     default:
3753       gold_unreachable();
3754     }
3755 }
3756
3757 // Create the version sections, sized version.
3758
3759 template<int size, bool big_endian>
3760 void
3761 Layout::sized_create_version_sections(
3762     const Versions* versions,
3763     const Symbol_table* symtab,
3764     unsigned int local_symcount,
3765     const std::vector<Symbol*>& dynamic_symbols,
3766     const Output_section* dynstr)
3767 {
3768   Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
3769                                                      elfcpp::SHT_GNU_versym,
3770                                                      elfcpp::SHF_ALLOC,
3771                                                      false,
3772                                                      ORDER_DYNAMIC_LINKER,
3773                                                      false);
3774
3775   unsigned char* vbuf;
3776   unsigned int vsize;
3777   versions->symbol_section_contents<size, big_endian>(symtab, &this->dynpool_,
3778                                                       local_symcount,
3779                                                       dynamic_symbols,
3780                                                       &vbuf, &vsize);
3781
3782   Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
3783                                                             "** versions");
3784
3785   vsec->add_output_section_data(vdata);
3786   vsec->set_entsize(2);
3787   vsec->set_link_section(this->dynsym_section_);
3788
3789   Output_data_dynamic* const odyn = this->dynamic_data_;
3790   odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
3791
3792   if (versions->any_defs())
3793     {
3794       Output_section* vdsec;
3795       vdsec= this->choose_output_section(NULL, ".gnu.version_d",
3796                                          elfcpp::SHT_GNU_verdef,
3797                                          elfcpp::SHF_ALLOC,
3798                                          false, ORDER_DYNAMIC_LINKER, false);
3799
3800       unsigned char* vdbuf;
3801       unsigned int vdsize;
3802       unsigned int vdentries;
3803       versions->def_section_contents<size, big_endian>(&this->dynpool_, &vdbuf,
3804                                                        &vdsize, &vdentries);
3805
3806       Output_section_data* vddata =
3807         new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
3808
3809       vdsec->add_output_section_data(vddata);
3810       vdsec->set_link_section(dynstr);
3811       vdsec->set_info(vdentries);
3812
3813       odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
3814       odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
3815     }
3816
3817   if (versions->any_needs())
3818     {
3819       Output_section* vnsec;
3820       vnsec = this->choose_output_section(NULL, ".gnu.version_r",
3821                                           elfcpp::SHT_GNU_verneed,
3822                                           elfcpp::SHF_ALLOC,
3823                                           false, ORDER_DYNAMIC_LINKER, false);
3824
3825       unsigned char* vnbuf;
3826       unsigned int vnsize;
3827       unsigned int vnentries;
3828       versions->need_section_contents<size, big_endian>(&this->dynpool_,
3829                                                         &vnbuf, &vnsize,
3830                                                         &vnentries);
3831
3832       Output_section_data* vndata =
3833         new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
3834
3835       vnsec->add_output_section_data(vndata);
3836       vnsec->set_link_section(dynstr);
3837       vnsec->set_info(vnentries);
3838
3839       odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
3840       odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
3841     }
3842 }
3843
3844 // Create the .interp section and PT_INTERP segment.
3845
3846 void
3847 Layout::create_interp(const Target* target)
3848 {
3849   const char* interp = parameters->options().dynamic_linker();
3850   if (interp == NULL)
3851     {
3852       interp = target->dynamic_linker();
3853       gold_assert(interp != NULL);
3854     }
3855
3856   size_t len = strlen(interp) + 1;
3857
3858   Output_section_data* odata = new Output_data_const(interp, len, 1);
3859
3860   Output_section* osec = this->choose_output_section(NULL, ".interp",
3861                                                      elfcpp::SHT_PROGBITS,
3862                                                      elfcpp::SHF_ALLOC,
3863                                                      false, ORDER_INTERP,
3864                                                      false);
3865   osec->add_output_section_data(odata);
3866
3867   if (!this->script_options_->saw_phdrs_clause())
3868     {
3869       Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP,
3870                                                        elfcpp::PF_R);
3871       oseg->add_output_section_to_nonload(osec, elfcpp::PF_R);
3872     }
3873 }
3874
3875 // Add dynamic tags for the PLT and the dynamic relocs.  This is
3876 // called by the target-specific code.  This does nothing if not doing
3877 // a dynamic link.
3878
3879 // USE_REL is true for REL relocs rather than RELA relocs.
3880
3881 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
3882
3883 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
3884 // and we also set DT_PLTREL.  We use PLT_REL's output section, since
3885 // some targets have multiple reloc sections in PLT_REL.
3886
3887 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
3888 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.
3889
3890 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
3891 // executable.
3892
3893 void
3894 Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
3895                                 const Output_data* plt_rel,
3896                                 const Output_data_reloc_generic* dyn_rel,
3897                                 bool add_debug, bool dynrel_includes_plt)
3898 {
3899   Output_data_dynamic* odyn = this->dynamic_data_;
3900   if (odyn == NULL)
3901     return;
3902
3903   if (plt_got != NULL && plt_got->output_section() != NULL)
3904     odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got);
3905
3906   if (plt_rel != NULL && plt_rel->output_section() != NULL)
3907     {
3908       odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section());
3909       odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section());
3910       odyn->add_constant(elfcpp::DT_PLTREL,
3911                          use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA);
3912     }
3913
3914   if (dyn_rel != NULL && dyn_rel->output_section() != NULL)
3915     {
3916       odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
3917                                 dyn_rel);
3918       if (plt_rel != NULL && dynrel_includes_plt)
3919         odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
3920                                dyn_rel, plt_rel);
3921       else
3922         odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
3923                                dyn_rel);
3924       const int size = parameters->target().get_size();
3925       elfcpp::DT rel_tag;
3926       int rel_size;
3927       if (use_rel)
3928         {
3929           rel_tag = elfcpp::DT_RELENT;
3930           if (size == 32)
3931             rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size;
3932           else if (size == 64)
3933             rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size;
3934           else
3935             gold_unreachable();
3936         }
3937       else
3938         {
3939           rel_tag = elfcpp::DT_RELAENT;
3940           if (size == 32)
3941             rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size;
3942           else if (size == 64)
3943             rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size;
3944           else
3945             gold_unreachable();
3946         }
3947       odyn->add_constant(rel_tag, rel_size);
3948
3949       if (parameters->options().combreloc())
3950         {
3951           size_t c = dyn_rel->relative_reloc_count();
3952           if (c > 0)
3953             odyn->add_constant((use_rel
3954                                 ? elfcpp::DT_RELCOUNT
3955                                 : elfcpp::DT_RELACOUNT),
3956                                c);
3957         }
3958     }
3959
3960   if (add_debug && !parameters->options().shared())
3961     {
3962       // The value of the DT_DEBUG tag is filled in by the dynamic
3963       // linker at run time, and used by the debugger.
3964       odyn->add_constant(elfcpp::DT_DEBUG, 0);
3965     }
3966 }
3967
3968 // Finish the .dynamic section and PT_DYNAMIC segment.
3969
3970 void
3971 Layout::finish_dynamic_section(const Input_objects* input_objects,
3972                                const Symbol_table* symtab)
3973 {
3974   if (!this->script_options_->saw_phdrs_clause())
3975     {
3976       Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
3977                                                        (elfcpp::PF_R
3978                                                         | elfcpp::PF_W));
3979       oseg->add_output_section_to_nonload(this->dynamic_section_,
3980                                           elfcpp::PF_R | elfcpp::PF_W);
3981     }
3982
3983   Output_data_dynamic* const odyn = this->dynamic_data_;
3984
3985   for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
3986        p != input_objects->dynobj_end();
3987        ++p)
3988     {
3989       if (!(*p)->is_needed() && (*p)->as_needed())
3990         {
3991           // This dynamic object was linked with --as-needed, but it
3992           // is not needed.
3993           continue;
3994         }
3995
3996       odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
3997     }
3998
3999   if (parameters->options().shared())
4000     {
4001       const char* soname = parameters->options().soname();
4002       if (soname != NULL)
4003         odyn->add_string(elfcpp::DT_SONAME, soname);
4004     }
4005
4006   Symbol* sym = symtab->lookup(parameters->options().init());
4007   if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4008     odyn->add_symbol(elfcpp::DT_INIT, sym);
4009
4010   sym = symtab->lookup(parameters->options().fini());
4011   if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4012     odyn->add_symbol(elfcpp::DT_FINI, sym);
4013
4014   // Look for .init_array, .preinit_array and .fini_array by checking
4015   // section types.
4016   for(Layout::Section_list::const_iterator p = this->section_list_.begin();
4017       p != this->section_list_.end();
4018       ++p)
4019     switch((*p)->type())
4020       {
4021       case elfcpp::SHT_FINI_ARRAY:
4022         odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p);
4023         odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p); 
4024         break;
4025       case elfcpp::SHT_INIT_ARRAY:
4026         odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p);
4027         odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p); 
4028         break;
4029       case elfcpp::SHT_PREINIT_ARRAY:
4030         odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p);
4031         odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p); 
4032         break;
4033       default:
4034         break;
4035       }
4036   
4037   // Add a DT_RPATH entry if needed.
4038   const General_options::Dir_list& rpath(parameters->options().rpath());
4039   if (!rpath.empty())
4040     {
4041       std::string rpath_val;
4042       for (General_options::Dir_list::const_iterator p = rpath.begin();
4043            p != rpath.end();
4044            ++p)
4045         {
4046           if (rpath_val.empty())
4047             rpath_val = p->name();
4048           else
4049             {
4050               // Eliminate duplicates.
4051               General_options::Dir_list::const_iterator q;
4052               for (q = rpath.begin(); q != p; ++q)
4053                 if (q->name() == p->name())
4054                   break;
4055               if (q == p)
4056                 {
4057                   rpath_val += ':';
4058                   rpath_val += p->name();
4059                 }
4060             }
4061         }
4062
4063       odyn->add_string(elfcpp::DT_RPATH, rpath_val);
4064       if (parameters->options().enable_new_dtags())
4065         odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
4066     }
4067
4068   // Look for text segments that have dynamic relocations.
4069   bool have_textrel = false;
4070   if (!this->script_options_->saw_sections_clause())
4071     {
4072       for (Segment_list::const_iterator p = this->segment_list_.begin();
4073            p != this->segment_list_.end();
4074            ++p)
4075         {
4076           if (((*p)->flags() & elfcpp::PF_W) == 0
4077               && (*p)->has_dynamic_reloc())
4078             {
4079               have_textrel = true;
4080               break;
4081             }
4082         }
4083     }
4084   else
4085     {
4086       // We don't know the section -> segment mapping, so we are
4087       // conservative and just look for readonly sections with
4088       // relocations.  If those sections wind up in writable segments,
4089       // then we have created an unnecessary DT_TEXTREL entry.
4090       for (Section_list::const_iterator p = this->section_list_.begin();
4091            p != this->section_list_.end();
4092            ++p)
4093         {
4094           if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
4095               && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
4096               && ((*p)->has_dynamic_reloc()))
4097             {
4098               have_textrel = true;
4099               break;
4100             }
4101         }
4102     }
4103
4104   // Add a DT_FLAGS entry. We add it even if no flags are set so that
4105   // post-link tools can easily modify these flags if desired.
4106   unsigned int flags = 0;
4107   if (have_textrel)
4108     {
4109       // Add a DT_TEXTREL for compatibility with older loaders.
4110       odyn->add_constant(elfcpp::DT_TEXTREL, 0);
4111       flags |= elfcpp::DF_TEXTREL;
4112
4113       if (parameters->options().text())
4114         gold_error(_("read-only segment has dynamic relocations"));
4115       else if (parameters->options().warn_shared_textrel()
4116                && parameters->options().shared())
4117         gold_warning(_("shared library text segment is not shareable"));
4118     }
4119   if (parameters->options().shared() && this->has_static_tls())
4120     flags |= elfcpp::DF_STATIC_TLS;
4121   if (parameters->options().origin())
4122     flags |= elfcpp::DF_ORIGIN;
4123   if (parameters->options().Bsymbolic())
4124     {
4125       flags |= elfcpp::DF_SYMBOLIC;
4126       // Add DT_SYMBOLIC for compatibility with older loaders.
4127       odyn->add_constant(elfcpp::DT_SYMBOLIC, 0);
4128     }
4129   if (parameters->options().now())
4130     flags |= elfcpp::DF_BIND_NOW;
4131   odyn->add_constant(elfcpp::DT_FLAGS, flags);
4132
4133   flags = 0;
4134   if (parameters->options().initfirst())
4135     flags |= elfcpp::DF_1_INITFIRST;
4136   if (parameters->options().interpose())
4137     flags |= elfcpp::DF_1_INTERPOSE;
4138   if (parameters->options().loadfltr())
4139     flags |= elfcpp::DF_1_LOADFLTR;
4140   if (parameters->options().nodefaultlib())
4141     flags |= elfcpp::DF_1_NODEFLIB;
4142   if (parameters->options().nodelete())
4143     flags |= elfcpp::DF_1_NODELETE;
4144   if (parameters->options().nodlopen())
4145     flags |= elfcpp::DF_1_NOOPEN;
4146   if (parameters->options().nodump())
4147     flags |= elfcpp::DF_1_NODUMP;
4148   if (!parameters->options().shared())
4149     flags &= ~(elfcpp::DF_1_INITFIRST
4150                | elfcpp::DF_1_NODELETE
4151                | elfcpp::DF_1_NOOPEN);
4152   if (parameters->options().origin())
4153     flags |= elfcpp::DF_1_ORIGIN;
4154   if (parameters->options().now())
4155     flags |= elfcpp::DF_1_NOW;
4156   if (flags)
4157     odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
4158 }
4159
4160 // Set the size of the _DYNAMIC symbol table to be the size of the
4161 // dynamic data.
4162
4163 void
4164 Layout::set_dynamic_symbol_size(const Symbol_table* symtab)
4165 {
4166   Output_data_dynamic* const odyn = this->dynamic_data_;
4167   odyn->finalize_data_size();
4168   off_t data_size = odyn->data_size();
4169   const int size = parameters->target().get_size();
4170   if (size == 32)
4171     symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size);
4172   else if (size == 64)
4173     symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size);
4174   else
4175     gold_unreachable();
4176 }
4177
4178 // The mapping of input section name prefixes to output section names.
4179 // In some cases one prefix is itself a prefix of another prefix; in
4180 // such a case the longer prefix must come first.  These prefixes are
4181 // based on the GNU linker default ELF linker script.
4182
4183 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4184 const Layout::Section_name_mapping Layout::section_name_mapping[] =
4185 {
4186   MAPPING_INIT(".text.", ".text"),
4187   MAPPING_INIT(".ctors.", ".ctors"),
4188   MAPPING_INIT(".dtors.", ".dtors"),
4189   MAPPING_INIT(".rodata.", ".rodata"),
4190   MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
4191   MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
4192   MAPPING_INIT(".data.", ".data"),
4193   MAPPING_INIT(".bss.", ".bss"),
4194   MAPPING_INIT(".tdata.", ".tdata"),
4195   MAPPING_INIT(".tbss.", ".tbss"),
4196   MAPPING_INIT(".init_array.", ".init_array"),
4197   MAPPING_INIT(".fini_array.", ".fini_array"),
4198   MAPPING_INIT(".sdata.", ".sdata"),
4199   MAPPING_INIT(".sbss.", ".sbss"),
4200   // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4201   // differently depending on whether it is creating a shared library.
4202   MAPPING_INIT(".sdata2.", ".sdata"),
4203   MAPPING_INIT(".sbss2.", ".sbss"),
4204   MAPPING_INIT(".lrodata.", ".lrodata"),
4205   MAPPING_INIT(".ldata.", ".ldata"),
4206   MAPPING_INIT(".lbss.", ".lbss"),
4207   MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4208   MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4209   MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4210   MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4211   MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4212   MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4213   MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4214   MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4215   MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4216   MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4217   MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4218   MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4219   MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4220   MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4221   MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4222   MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
4223   MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
4224   MAPPING_INIT(".ARM.extab", ".ARM.extab"),
4225   MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
4226   MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
4227   MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
4228 };
4229 #undef MAPPING_INIT
4230
4231 const int Layout::section_name_mapping_count =
4232   (sizeof(Layout::section_name_mapping)
4233    / sizeof(Layout::section_name_mapping[0]));
4234
4235 // Choose the output section name to use given an input section name.
4236 // Set *PLEN to the length of the name.  *PLEN is initialized to the
4237 // length of NAME.
4238
4239 const char*
4240 Layout::output_section_name(const char* name, size_t* plen)
4241 {
4242   // gcc 4.3 generates the following sorts of section names when it
4243   // needs a section name specific to a function:
4244   //   .text.FN
4245   //   .rodata.FN
4246   //   .sdata2.FN
4247   //   .data.FN
4248   //   .data.rel.FN
4249   //   .data.rel.local.FN
4250   //   .data.rel.ro.FN
4251   //   .data.rel.ro.local.FN
4252   //   .sdata.FN
4253   //   .bss.FN
4254   //   .sbss.FN
4255   //   .tdata.FN
4256   //   .tbss.FN
4257
4258   // The GNU linker maps all of those to the part before the .FN,
4259   // except that .data.rel.local.FN is mapped to .data, and
4260   // .data.rel.ro.local.FN is mapped to .data.rel.ro.  The sections
4261   // beginning with .data.rel.ro.local are grouped together.
4262
4263   // For an anonymous namespace, the string FN can contain a '.'.
4264
4265   // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
4266   // GNU linker maps to .rodata.
4267
4268   // The .data.rel.ro sections are used with -z relro.  The sections
4269   // are recognized by name.  We use the same names that the GNU
4270   // linker does for these sections.
4271
4272   // It is hard to handle this in a principled way, so we don't even
4273   // try.  We use a table of mappings.  If the input section name is
4274   // not found in the table, we simply use it as the output section
4275   // name.
4276
4277   const Section_name_mapping* psnm = section_name_mapping;
4278   for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
4279     {
4280       if (strncmp(name, psnm->from, psnm->fromlen) == 0)
4281         {
4282           *plen = psnm->tolen;
4283           return psnm->to;
4284         }
4285     }
4286
4287   return name;
4288 }
4289
4290 // Check if a comdat group or .gnu.linkonce section with the given
4291 // NAME is selected for the link.  If there is already a section,
4292 // *KEPT_SECTION is set to point to the existing section and the
4293 // function returns false.  Otherwise, OBJECT, SHNDX, IS_COMDAT, and
4294 // IS_GROUP_NAME are recorded for this NAME in the layout object,
4295 // *KEPT_SECTION is set to the internal copy and the function returns
4296 // true.
4297
4298 bool
4299 Layout::find_or_add_kept_section(const std::string& name,
4300                                  Relobj* object,
4301                                  unsigned int shndx,
4302                                  bool is_comdat,
4303                                  bool is_group_name,
4304                                  Kept_section** kept_section)
4305 {
4306   // It's normal to see a couple of entries here, for the x86 thunk
4307   // sections.  If we see more than a few, we're linking a C++
4308   // program, and we resize to get more space to minimize rehashing.
4309   if (this->signatures_.size() > 4
4310       && !this->resized_signatures_)
4311     {
4312       reserve_unordered_map(&this->signatures_,
4313                             this->number_of_input_files_ * 64);
4314       this->resized_signatures_ = true;
4315     }
4316
4317   Kept_section candidate;
4318   std::pair<Signatures::iterator, bool> ins =
4319     this->signatures_.insert(std::make_pair(name, candidate));
4320
4321   if (kept_section != NULL)
4322     *kept_section = &ins.first->second;
4323   if (ins.second)
4324     {
4325       // This is the first time we've seen this signature.
4326       ins.first->second.set_object(object);
4327       ins.first->second.set_shndx(shndx);
4328       if (is_comdat)
4329         ins.first->second.set_is_comdat();
4330       if (is_group_name)
4331         ins.first->second.set_is_group_name();
4332       return true;
4333     }
4334
4335   // We have already seen this signature.
4336
4337   if (ins.first->second.is_group_name())
4338     {
4339       // We've already seen a real section group with this signature.
4340       // If the kept group is from a plugin object, and we're in the
4341       // replacement phase, accept the new one as a replacement.
4342       if (ins.first->second.object() == NULL
4343           && parameters->options().plugins()->in_replacement_phase())
4344         {
4345           ins.first->second.set_object(object);
4346           ins.first->second.set_shndx(shndx);
4347           return true;
4348         }
4349       return false;
4350     }
4351   else if (is_group_name)
4352     {
4353       // This is a real section group, and we've already seen a
4354       // linkonce section with this signature.  Record that we've seen
4355       // a section group, and don't include this section group.
4356       ins.first->second.set_is_group_name();
4357       return false;
4358     }
4359   else
4360     {
4361       // We've already seen a linkonce section and this is a linkonce
4362       // section.  These don't block each other--this may be the same
4363       // symbol name with different section types.
4364       return true;
4365     }
4366 }
4367
4368 // Store the allocated sections into the section list.
4369
4370 void
4371 Layout::get_allocated_sections(Section_list* section_list) const
4372 {
4373   for (Section_list::const_iterator p = this->section_list_.begin();
4374        p != this->section_list_.end();
4375        ++p)
4376     if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
4377       section_list->push_back(*p);
4378 }
4379
4380 // Create an output segment.
4381
4382 Output_segment*
4383 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
4384 {
4385   gold_assert(!parameters->options().relocatable());
4386   Output_segment* oseg = new Output_segment(type, flags);
4387   this->segment_list_.push_back(oseg);
4388
4389   if (type == elfcpp::PT_TLS)
4390     this->tls_segment_ = oseg;
4391   else if (type == elfcpp::PT_GNU_RELRO)
4392     this->relro_segment_ = oseg;
4393
4394   return oseg;
4395 }
4396
4397 // Return the file offset of the normal symbol table.
4398
4399 off_t
4400 Layout::symtab_section_offset() const
4401 {
4402   if (this->symtab_section_ != NULL)
4403     return this->symtab_section_->offset();
4404   return 0;
4405 }
4406
4407 // Write out the Output_sections.  Most won't have anything to write,
4408 // since most of the data will come from input sections which are
4409 // handled elsewhere.  But some Output_sections do have Output_data.
4410
4411 void
4412 Layout::write_output_sections(Output_file* of) const
4413 {
4414   for (Section_list::const_iterator p = this->section_list_.begin();
4415        p != this->section_list_.end();
4416        ++p)
4417     {
4418       if (!(*p)->after_input_sections())
4419         (*p)->write(of);
4420     }
4421 }
4422
4423 // Write out data not associated with a section or the symbol table.
4424
4425 void
4426 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
4427 {
4428   if (!parameters->options().strip_all())
4429     {
4430       const Output_section* symtab_section = this->symtab_section_;
4431       for (Section_list::const_iterator p = this->section_list_.begin();
4432            p != this->section_list_.end();
4433            ++p)
4434         {
4435           if ((*p)->needs_symtab_index())
4436             {
4437               gold_assert(symtab_section != NULL);
4438               unsigned int index = (*p)->symtab_index();
4439               gold_assert(index > 0 && index != -1U);
4440               off_t off = (symtab_section->offset()
4441                            + index * symtab_section->entsize());
4442               symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
4443             }
4444         }
4445     }
4446
4447   const Output_section* dynsym_section = this->dynsym_section_;
4448   for (Section_list::const_iterator p = this->section_list_.begin();
4449        p != this->section_list_.end();
4450        ++p)
4451     {
4452       if ((*p)->needs_dynsym_index())
4453         {
4454           gold_assert(dynsym_section != NULL);
4455           unsigned int index = (*p)->dynsym_index();
4456           gold_assert(index > 0 && index != -1U);
4457           off_t off = (dynsym_section->offset()
4458                        + index * dynsym_section->entsize());
4459           symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
4460         }
4461     }
4462
4463   // Write out the Output_data which are not in an Output_section.
4464   for (Data_list::const_iterator p = this->special_output_list_.begin();
4465        p != this->special_output_list_.end();
4466        ++p)
4467     (*p)->write(of);
4468 }
4469
4470 // Write out the Output_sections which can only be written after the
4471 // input sections are complete.
4472
4473 void
4474 Layout::write_sections_after_input_sections(Output_file* of)
4475 {
4476   // Determine the final section offsets, and thus the final output
4477   // file size.  Note we finalize the .shstrab last, to allow the
4478   // after_input_section sections to modify their section-names before
4479   // writing.
4480   if (this->any_postprocessing_sections_)
4481     {
4482       off_t off = this->output_file_size_;
4483       off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
4484
4485       // Now that we've finalized the names, we can finalize the shstrab.
4486       off =
4487         this->set_section_offsets(off,
4488                                   STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
4489
4490       if (off > this->output_file_size_)
4491         {
4492           of->resize(off);
4493           this->output_file_size_ = off;
4494         }
4495     }
4496
4497   for (Section_list::const_iterator p = this->section_list_.begin();
4498        p != this->section_list_.end();
4499        ++p)
4500     {
4501       if ((*p)->after_input_sections())
4502         (*p)->write(of);
4503     }
4504
4505   this->section_headers_->write(of);
4506 }
4507
4508 // If the build ID requires computing a checksum, do so here, and
4509 // write it out.  We compute a checksum over the entire file because
4510 // that is simplest.
4511
4512 void
4513 Layout::write_build_id(Output_file* of) const
4514 {
4515   if (this->build_id_note_ == NULL)
4516     return;
4517
4518   const unsigned char* iv = of->get_input_view(0, this->output_file_size_);
4519
4520   unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
4521                                           this->build_id_note_->data_size());
4522
4523   const char* style = parameters->options().build_id();
4524   if (strcmp(style, "sha1") == 0)
4525     {
4526       sha1_ctx ctx;
4527       sha1_init_ctx(&ctx);
4528       sha1_process_bytes(iv, this->output_file_size_, &ctx);
4529       sha1_finish_ctx(&ctx, ov);
4530     }
4531   else if (strcmp(style, "md5") == 0)
4532     {
4533       md5_ctx ctx;
4534       md5_init_ctx(&ctx);
4535       md5_process_bytes(iv, this->output_file_size_, &ctx);
4536       md5_finish_ctx(&ctx, ov);
4537     }
4538   else
4539     gold_unreachable();
4540
4541   of->write_output_view(this->build_id_note_->offset(),
4542                         this->build_id_note_->data_size(),
4543                         ov);
4544
4545   of->free_input_view(0, this->output_file_size_, iv);
4546 }
4547
4548 // Write out a binary file.  This is called after the link is
4549 // complete.  IN is the temporary output file we used to generate the
4550 // ELF code.  We simply walk through the segments, read them from
4551 // their file offset in IN, and write them to their load address in
4552 // the output file.  FIXME: with a bit more work, we could support
4553 // S-records and/or Intel hex format here.
4554
4555 void
4556 Layout::write_binary(Output_file* in) const
4557 {
4558   gold_assert(parameters->options().oformat_enum()
4559               == General_options::OBJECT_FORMAT_BINARY);
4560
4561   // Get the size of the binary file.
4562   uint64_t max_load_address = 0;
4563   for (Segment_list::const_iterator p = this->segment_list_.begin();
4564        p != this->segment_list_.end();
4565        ++p)
4566     {
4567       if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
4568         {
4569           uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
4570           if (max_paddr > max_load_address)
4571             max_load_address = max_paddr;
4572         }
4573     }
4574
4575   Output_file out(parameters->options().output_file_name());
4576   out.open(max_load_address);
4577
4578   for (Segment_list::const_iterator p = this->segment_list_.begin();
4579        p != this->segment_list_.end();
4580        ++p)
4581     {
4582       if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
4583         {
4584           const unsigned char* vin = in->get_input_view((*p)->offset(),
4585                                                         (*p)->filesz());
4586           unsigned char* vout = out.get_output_view((*p)->paddr(),
4587                                                     (*p)->filesz());
4588           memcpy(vout, vin, (*p)->filesz());
4589           out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
4590           in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
4591         }
4592     }
4593
4594   out.close();
4595 }
4596
4597 // Print the output sections to the map file.
4598
4599 void
4600 Layout::print_to_mapfile(Mapfile* mapfile) const
4601 {
4602   for (Segment_list::const_iterator p = this->segment_list_.begin();
4603        p != this->segment_list_.end();
4604        ++p)
4605     (*p)->print_sections_to_mapfile(mapfile);
4606 }
4607
4608 // Print statistical information to stderr.  This is used for --stats.
4609
4610 void
4611 Layout::print_stats() const
4612 {
4613   this->namepool_.print_stats("section name pool");
4614   this->sympool_.print_stats("output symbol name pool");
4615   this->dynpool_.print_stats("dynamic name pool");
4616
4617   for (Section_list::const_iterator p = this->section_list_.begin();
4618        p != this->section_list_.end();
4619        ++p)
4620     (*p)->print_merge_stats();
4621 }
4622
4623 // Write_sections_task methods.
4624
4625 // We can always run this task.
4626
4627 Task_token*
4628 Write_sections_task::is_runnable()
4629 {
4630   return NULL;
4631 }
4632
4633 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
4634 // when finished.
4635
4636 void
4637 Write_sections_task::locks(Task_locker* tl)
4638 {
4639   tl->add(this, this->output_sections_blocker_);
4640   tl->add(this, this->final_blocker_);
4641 }
4642
4643 // Run the task--write out the data.
4644
4645 void
4646 Write_sections_task::run(Workqueue*)
4647 {
4648   this->layout_->write_output_sections(this->of_);
4649 }
4650
4651 // Write_data_task methods.
4652
4653 // We can always run this task.
4654
4655 Task_token*
4656 Write_data_task::is_runnable()
4657 {
4658   return NULL;
4659 }
4660
4661 // We need to unlock FINAL_BLOCKER when finished.
4662
4663 void
4664 Write_data_task::locks(Task_locker* tl)
4665 {
4666   tl->add(this, this->final_blocker_);
4667 }
4668
4669 // Run the task--write out the data.
4670
4671 void
4672 Write_data_task::run(Workqueue*)
4673 {
4674   this->layout_->write_data(this->symtab_, this->of_);
4675 }
4676
4677 // Write_symbols_task methods.
4678
4679 // We can always run this task.
4680
4681 Task_token*
4682 Write_symbols_task::is_runnable()
4683 {
4684   return NULL;
4685 }
4686
4687 // We need to unlock FINAL_BLOCKER when finished.
4688
4689 void
4690 Write_symbols_task::locks(Task_locker* tl)
4691 {
4692   tl->add(this, this->final_blocker_);
4693 }
4694
4695 // Run the task--write out the symbols.
4696
4697 void
4698 Write_symbols_task::run(Workqueue*)
4699 {
4700   this->symtab_->write_globals(this->sympool_, this->dynpool_,
4701                                this->layout_->symtab_xindex(),
4702                                this->layout_->dynsym_xindex(), this->of_);
4703 }
4704
4705 // Write_after_input_sections_task methods.
4706
4707 // We can only run this task after the input sections have completed.
4708
4709 Task_token*
4710 Write_after_input_sections_task::is_runnable()
4711 {
4712   if (this->input_sections_blocker_->is_blocked())
4713     return this->input_sections_blocker_;
4714   return NULL;
4715 }
4716
4717 // We need to unlock FINAL_BLOCKER when finished.
4718
4719 void
4720 Write_after_input_sections_task::locks(Task_locker* tl)
4721 {
4722   tl->add(this, this->final_blocker_);
4723 }
4724
4725 // Run the task.
4726
4727 void
4728 Write_after_input_sections_task::run(Workqueue*)
4729 {
4730   this->layout_->write_sections_after_input_sections(this->of_);
4731 }
4732
4733 // Close_task_runner methods.
4734
4735 // Run the task--close the file.
4736
4737 void
4738 Close_task_runner::run(Workqueue*, const Task*)
4739 {
4740   // If we need to compute a checksum for the BUILD if, we do so here.
4741   this->layout_->write_build_id(this->of_);
4742
4743   // If we've been asked to create a binary file, we do so here.
4744   if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
4745     this->layout_->write_binary(this->of_);
4746
4747   this->of_->close();
4748 }
4749
4750 // Instantiate the templates we need.  We could use the configure
4751 // script to restrict this to only the ones for implemented targets.
4752
4753 #ifdef HAVE_TARGET_32_LITTLE
4754 template
4755 Output_section*
4756 Layout::init_fixed_output_section<32, false>(
4757     const char* name,
4758     elfcpp::Shdr<32, false>& shdr);
4759 #endif
4760
4761 #ifdef HAVE_TARGET_32_BIG
4762 template
4763 Output_section*
4764 Layout::init_fixed_output_section<32, true>(
4765     const char* name,
4766     elfcpp::Shdr<32, true>& shdr);
4767 #endif
4768
4769 #ifdef HAVE_TARGET_64_LITTLE
4770 template
4771 Output_section*
4772 Layout::init_fixed_output_section<64, false>(
4773     const char* name,
4774     elfcpp::Shdr<64, false>& shdr);
4775 #endif
4776
4777 #ifdef HAVE_TARGET_64_BIG
4778 template
4779 Output_section*
4780 Layout::init_fixed_output_section<64, true>(
4781     const char* name,
4782     elfcpp::Shdr<64, true>& shdr);
4783 #endif
4784
4785 #ifdef HAVE_TARGET_32_LITTLE
4786 template
4787 Output_section*
4788 Layout::layout<32, false>(Sized_relobj_file<32, false>* object,
4789                           unsigned int shndx,
4790                           const char* name,
4791                           const elfcpp::Shdr<32, false>& shdr,
4792                           unsigned int, unsigned int, off_t*);
4793 #endif
4794
4795 #ifdef HAVE_TARGET_32_BIG
4796 template
4797 Output_section*
4798 Layout::layout<32, true>(Sized_relobj_file<32, true>* object,
4799                          unsigned int shndx,
4800                          const char* name,
4801                          const elfcpp::Shdr<32, true>& shdr,
4802                          unsigned int, unsigned int, off_t*);
4803 #endif
4804
4805 #ifdef HAVE_TARGET_64_LITTLE
4806 template
4807 Output_section*
4808 Layout::layout<64, false>(Sized_relobj_file<64, false>* object,
4809                           unsigned int shndx,
4810                           const char* name,
4811                           const elfcpp::Shdr<64, false>& shdr,
4812                           unsigned int, unsigned int, off_t*);
4813 #endif
4814
4815 #ifdef HAVE_TARGET_64_BIG
4816 template
4817 Output_section*
4818 Layout::layout<64, true>(Sized_relobj_file<64, true>* object,
4819                          unsigned int shndx,
4820                          const char* name,
4821                          const elfcpp::Shdr<64, true>& shdr,
4822                          unsigned int, unsigned int, off_t*);
4823 #endif
4824
4825 #ifdef HAVE_TARGET_32_LITTLE
4826 template
4827 Output_section*
4828 Layout::layout_reloc<32, false>(Sized_relobj_file<32, false>* object,
4829                                 unsigned int reloc_shndx,
4830                                 const elfcpp::Shdr<32, false>& shdr,
4831                                 Output_section* data_section,
4832                                 Relocatable_relocs* rr);
4833 #endif
4834
4835 #ifdef HAVE_TARGET_32_BIG
4836 template
4837 Output_section*
4838 Layout::layout_reloc<32, true>(Sized_relobj_file<32, true>* object,
4839                                unsigned int reloc_shndx,
4840                                const elfcpp::Shdr<32, true>& shdr,
4841                                Output_section* data_section,
4842                                Relocatable_relocs* rr);
4843 #endif
4844
4845 #ifdef HAVE_TARGET_64_LITTLE
4846 template
4847 Output_section*
4848 Layout::layout_reloc<64, false>(Sized_relobj_file<64, false>* object,
4849                                 unsigned int reloc_shndx,
4850                                 const elfcpp::Shdr<64, false>& shdr,
4851                                 Output_section* data_section,
4852                                 Relocatable_relocs* rr);
4853 #endif
4854
4855 #ifdef HAVE_TARGET_64_BIG
4856 template
4857 Output_section*
4858 Layout::layout_reloc<64, true>(Sized_relobj_file<64, true>* object,
4859                                unsigned int reloc_shndx,
4860                                const elfcpp::Shdr<64, true>& shdr,
4861                                Output_section* data_section,
4862                                Relocatable_relocs* rr);
4863 #endif
4864
4865 #ifdef HAVE_TARGET_32_LITTLE
4866 template
4867 void
4868 Layout::layout_group<32, false>(Symbol_table* symtab,
4869                                 Sized_relobj_file<32, false>* object,
4870                                 unsigned int,
4871                                 const char* group_section_name,
4872                                 const char* signature,
4873                                 const elfcpp::Shdr<32, false>& shdr,
4874                                 elfcpp::Elf_Word flags,
4875                                 std::vector<unsigned int>* shndxes);
4876 #endif
4877
4878 #ifdef HAVE_TARGET_32_BIG
4879 template
4880 void
4881 Layout::layout_group<32, true>(Symbol_table* symtab,
4882                                Sized_relobj_file<32, true>* object,
4883                                unsigned int,
4884                                const char* group_section_name,
4885                                const char* signature,
4886                                const elfcpp::Shdr<32, true>& shdr,
4887                                elfcpp::Elf_Word flags,
4888                                std::vector<unsigned int>* shndxes);
4889 #endif
4890
4891 #ifdef HAVE_TARGET_64_LITTLE
4892 template
4893 void
4894 Layout::layout_group<64, false>(Symbol_table* symtab,
4895                                 Sized_relobj_file<64, false>* object,
4896                                 unsigned int,
4897                                 const char* group_section_name,
4898                                 const char* signature,
4899                                 const elfcpp::Shdr<64, false>& shdr,
4900                                 elfcpp::Elf_Word flags,
4901                                 std::vector<unsigned int>* shndxes);
4902 #endif
4903
4904 #ifdef HAVE_TARGET_64_BIG
4905 template
4906 void
4907 Layout::layout_group<64, true>(Symbol_table* symtab,
4908                                Sized_relobj_file<64, true>* object,
4909                                unsigned int,
4910                                const char* group_section_name,
4911                                const char* signature,
4912                                const elfcpp::Shdr<64, true>& shdr,
4913                                elfcpp::Elf_Word flags,
4914                                std::vector<unsigned int>* shndxes);
4915 #endif
4916
4917 #ifdef HAVE_TARGET_32_LITTLE
4918 template
4919 Output_section*
4920 Layout::layout_eh_frame<32, false>(Sized_relobj_file<32, false>* object,
4921                                    const unsigned char* symbols,
4922                                    off_t symbols_size,
4923                                    const unsigned char* symbol_names,
4924                                    off_t symbol_names_size,
4925                                    unsigned int shndx,
4926                                    const elfcpp::Shdr<32, false>& shdr,
4927                                    unsigned int reloc_shndx,
4928                                    unsigned int reloc_type,
4929                                    off_t* off);
4930 #endif
4931
4932 #ifdef HAVE_TARGET_32_BIG
4933 template
4934 Output_section*
4935 Layout::layout_eh_frame<32, true>(Sized_relobj_file<32, true>* object,
4936                                   const unsigned char* symbols,
4937                                   off_t symbols_size,
4938                                   const unsigned char* symbol_names,
4939                                   off_t symbol_names_size,
4940                                   unsigned int shndx,
4941                                   const elfcpp::Shdr<32, true>& shdr,
4942                                   unsigned int reloc_shndx,
4943                                   unsigned int reloc_type,
4944                                   off_t* off);
4945 #endif
4946
4947 #ifdef HAVE_TARGET_64_LITTLE
4948 template
4949 Output_section*
4950 Layout::layout_eh_frame<64, false>(Sized_relobj_file<64, false>* object,
4951                                    const unsigned char* symbols,
4952                                    off_t symbols_size,
4953                                    const unsigned char* symbol_names,
4954                                    off_t symbol_names_size,
4955                                    unsigned int shndx,
4956                                    const elfcpp::Shdr<64, false>& shdr,
4957                                    unsigned int reloc_shndx,
4958                                    unsigned int reloc_type,
4959                                    off_t* off);
4960 #endif
4961
4962 #ifdef HAVE_TARGET_64_BIG
4963 template
4964 Output_section*
4965 Layout::layout_eh_frame<64, true>(Sized_relobj_file<64, true>* object,
4966                                   const unsigned char* symbols,
4967                                   off_t symbols_size,
4968                                   const unsigned char* symbol_names,
4969                                   off_t symbol_names_size,
4970                                   unsigned int shndx,
4971                                   const elfcpp::Shdr<64, true>& shdr,
4972                                   unsigned int reloc_shndx,
4973                                   unsigned int reloc_type,
4974                                   off_t* off);
4975 #endif
4976
4977 } // End namespace gold.