* powerpc.cc (Target_selector_powerpc::Target_selector_powerpc):
[platform/upstream/binutils.git] / gold / object.cc
1 // object.cc -- support for an object file for linking in gold
2
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012
4 // Free Software Foundation, Inc.
5 // Written by Ian Lance Taylor <iant@google.com>.
6
7 // This file is part of gold.
8
9 // This program is free software; you can redistribute it and/or modify
10 // it under the terms of the GNU General Public License as published by
11 // the Free Software Foundation; either version 3 of the License, or
12 // (at your option) any later version.
13
14 // This program is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 // GNU General Public License for more details.
18
19 // You should have received a copy of the GNU General Public License
20 // along with this program; if not, write to the Free Software
21 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22 // MA 02110-1301, USA.
23
24 #include "gold.h"
25
26 #include <cerrno>
27 #include <cstring>
28 #include <cstdarg>
29 #include "demangle.h"
30 #include "libiberty.h"
31
32 #include "gc.h"
33 #include "target-select.h"
34 #include "dwarf_reader.h"
35 #include "layout.h"
36 #include "output.h"
37 #include "symtab.h"
38 #include "cref.h"
39 #include "reloc.h"
40 #include "object.h"
41 #include "dynobj.h"
42 #include "plugin.h"
43 #include "compressed_output.h"
44 #include "incremental.h"
45
46 namespace gold
47 {
48
49 // Struct Read_symbols_data.
50
51 // Destroy any remaining File_view objects and buffers of decompressed
52 // sections.
53
54 Read_symbols_data::~Read_symbols_data()
55 {
56   if (this->section_headers != NULL)
57     delete this->section_headers;
58   if (this->section_names != NULL)
59     delete this->section_names;
60   if (this->symbols != NULL)
61     delete this->symbols;
62   if (this->symbol_names != NULL)
63     delete this->symbol_names;
64   if (this->versym != NULL)
65     delete this->versym;
66   if (this->verdef != NULL)
67     delete this->verdef;
68   if (this->verneed != NULL)
69     delete this->verneed;
70 }
71
72 // Class Xindex.
73
74 // Initialize the symtab_xindex_ array.  Find the SHT_SYMTAB_SHNDX
75 // section and read it in.  SYMTAB_SHNDX is the index of the symbol
76 // table we care about.
77
78 template<int size, bool big_endian>
79 void
80 Xindex::initialize_symtab_xindex(Object* object, unsigned int symtab_shndx)
81 {
82   if (!this->symtab_xindex_.empty())
83     return;
84
85   gold_assert(symtab_shndx != 0);
86
87   // Look through the sections in reverse order, on the theory that it
88   // is more likely to be near the end than the beginning.
89   unsigned int i = object->shnum();
90   while (i > 0)
91     {
92       --i;
93       if (object->section_type(i) == elfcpp::SHT_SYMTAB_SHNDX
94           && this->adjust_shndx(object->section_link(i)) == symtab_shndx)
95         {
96           this->read_symtab_xindex<size, big_endian>(object, i, NULL);
97           return;
98         }
99     }
100
101   object->error(_("missing SHT_SYMTAB_SHNDX section"));
102 }
103
104 // Read in the symtab_xindex_ array, given the section index of the
105 // SHT_SYMTAB_SHNDX section.  If PSHDRS is not NULL, it points at the
106 // section headers.
107
108 template<int size, bool big_endian>
109 void
110 Xindex::read_symtab_xindex(Object* object, unsigned int xindex_shndx,
111                            const unsigned char* pshdrs)
112 {
113   section_size_type bytecount;
114   const unsigned char* contents;
115   if (pshdrs == NULL)
116     contents = object->section_contents(xindex_shndx, &bytecount, false);
117   else
118     {
119       const unsigned char* p = (pshdrs
120                                 + (xindex_shndx
121                                    * elfcpp::Elf_sizes<size>::shdr_size));
122       typename elfcpp::Shdr<size, big_endian> shdr(p);
123       bytecount = convert_to_section_size_type(shdr.get_sh_size());
124       contents = object->get_view(shdr.get_sh_offset(), bytecount, true, false);
125     }
126
127   gold_assert(this->symtab_xindex_.empty());
128   this->symtab_xindex_.reserve(bytecount / 4);
129   for (section_size_type i = 0; i < bytecount; i += 4)
130     {
131       unsigned int shndx = elfcpp::Swap<32, big_endian>::readval(contents + i);
132       // We preadjust the section indexes we save.
133       this->symtab_xindex_.push_back(this->adjust_shndx(shndx));
134     }
135 }
136
137 // Symbol symndx has a section of SHN_XINDEX; return the real section
138 // index.
139
140 unsigned int
141 Xindex::sym_xindex_to_shndx(Object* object, unsigned int symndx)
142 {
143   if (symndx >= this->symtab_xindex_.size())
144     {
145       object->error(_("symbol %u out of range for SHT_SYMTAB_SHNDX section"),
146                     symndx);
147       return elfcpp::SHN_UNDEF;
148     }
149   unsigned int shndx = this->symtab_xindex_[symndx];
150   if (shndx < elfcpp::SHN_LORESERVE || shndx >= object->shnum())
151     {
152       object->error(_("extended index for symbol %u out of range: %u"),
153                     symndx, shndx);
154       return elfcpp::SHN_UNDEF;
155     }
156   return shndx;
157 }
158
159 // Class Object.
160
161 // Report an error for this object file.  This is used by the
162 // elfcpp::Elf_file interface, and also called by the Object code
163 // itself.
164
165 void
166 Object::error(const char* format, ...) const
167 {
168   va_list args;
169   va_start(args, format);
170   char* buf = NULL;
171   if (vasprintf(&buf, format, args) < 0)
172     gold_nomem();
173   va_end(args);
174   gold_error(_("%s: %s"), this->name().c_str(), buf);
175   free(buf);
176 }
177
178 // Return a view of the contents of a section.
179
180 const unsigned char*
181 Object::section_contents(unsigned int shndx, section_size_type* plen,
182                          bool cache)
183 { return this->do_section_contents(shndx, plen, cache); }
184
185 // Read the section data into SD.  This is code common to Sized_relobj_file
186 // and Sized_dynobj, so we put it into Object.
187
188 template<int size, bool big_endian>
189 void
190 Object::read_section_data(elfcpp::Elf_file<size, big_endian, Object>* elf_file,
191                           Read_symbols_data* sd)
192 {
193   const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
194
195   // Read the section headers.
196   const off_t shoff = elf_file->shoff();
197   const unsigned int shnum = this->shnum();
198   sd->section_headers = this->get_lasting_view(shoff, shnum * shdr_size,
199                                                true, true);
200
201   // Read the section names.
202   const unsigned char* pshdrs = sd->section_headers->data();
203   const unsigned char* pshdrnames = pshdrs + elf_file->shstrndx() * shdr_size;
204   typename elfcpp::Shdr<size, big_endian> shdrnames(pshdrnames);
205
206   if (shdrnames.get_sh_type() != elfcpp::SHT_STRTAB)
207     this->error(_("section name section has wrong type: %u"),
208                 static_cast<unsigned int>(shdrnames.get_sh_type()));
209
210   sd->section_names_size =
211     convert_to_section_size_type(shdrnames.get_sh_size());
212   sd->section_names = this->get_lasting_view(shdrnames.get_sh_offset(),
213                                              sd->section_names_size, false,
214                                              false);
215 }
216
217 // If NAME is the name of a special .gnu.warning section, arrange for
218 // the warning to be issued.  SHNDX is the section index.  Return
219 // whether it is a warning section.
220
221 bool
222 Object::handle_gnu_warning_section(const char* name, unsigned int shndx,
223                                    Symbol_table* symtab)
224 {
225   const char warn_prefix[] = ".gnu.warning.";
226   const int warn_prefix_len = sizeof warn_prefix - 1;
227   if (strncmp(name, warn_prefix, warn_prefix_len) == 0)
228     {
229       // Read the section contents to get the warning text.  It would
230       // be nicer if we only did this if we have to actually issue a
231       // warning.  Unfortunately, warnings are issued as we relocate
232       // sections.  That means that we can not lock the object then,
233       // as we might try to issue the same warning multiple times
234       // simultaneously.
235       section_size_type len;
236       const unsigned char* contents = this->section_contents(shndx, &len,
237                                                              false);
238       if (len == 0)
239         {
240           const char* warning = name + warn_prefix_len;
241           contents = reinterpret_cast<const unsigned char*>(warning);
242           len = strlen(warning);
243         }
244       std::string warning(reinterpret_cast<const char*>(contents), len);
245       symtab->add_warning(name + warn_prefix_len, this, warning);
246       return true;
247     }
248   return false;
249 }
250
251 // If NAME is the name of the special section which indicates that
252 // this object was compiled with -fsplit-stack, mark it accordingly.
253
254 bool
255 Object::handle_split_stack_section(const char* name)
256 {
257   if (strcmp(name, ".note.GNU-split-stack") == 0)
258     {
259       this->uses_split_stack_ = true;
260       return true;
261     }
262   if (strcmp(name, ".note.GNU-no-split-stack") == 0)
263     {
264       this->has_no_split_stack_ = true;
265       return true;
266     }
267   return false;
268 }
269
270 // Class Relobj
271
272 // To copy the symbols data read from the file to a local data structure.
273 // This function is called from do_layout only while doing garbage
274 // collection.
275
276 void
277 Relobj::copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd,
278                           unsigned int section_header_size)
279 {
280   gc_sd->section_headers_data =
281          new unsigned char[(section_header_size)];
282   memcpy(gc_sd->section_headers_data, sd->section_headers->data(),
283          section_header_size);
284   gc_sd->section_names_data =
285          new unsigned char[sd->section_names_size];
286   memcpy(gc_sd->section_names_data, sd->section_names->data(),
287          sd->section_names_size);
288   gc_sd->section_names_size = sd->section_names_size;
289   if (sd->symbols != NULL)
290     {
291       gc_sd->symbols_data =
292              new unsigned char[sd->symbols_size];
293       memcpy(gc_sd->symbols_data, sd->symbols->data(),
294             sd->symbols_size);
295     }
296   else
297     {
298       gc_sd->symbols_data = NULL;
299     }
300   gc_sd->symbols_size = sd->symbols_size;
301   gc_sd->external_symbols_offset = sd->external_symbols_offset;
302   if (sd->symbol_names != NULL)
303     {
304       gc_sd->symbol_names_data =
305              new unsigned char[sd->symbol_names_size];
306       memcpy(gc_sd->symbol_names_data, sd->symbol_names->data(),
307             sd->symbol_names_size);
308     }
309   else
310     {
311       gc_sd->symbol_names_data = NULL;
312     }
313   gc_sd->symbol_names_size = sd->symbol_names_size;
314 }
315
316 // This function determines if a particular section name must be included
317 // in the link.  This is used during garbage collection to determine the
318 // roots of the worklist.
319
320 bool
321 Relobj::is_section_name_included(const char* name)
322 {
323   if (is_prefix_of(".ctors", name)
324       || is_prefix_of(".dtors", name)
325       || is_prefix_of(".note", name)
326       || is_prefix_of(".init", name)
327       || is_prefix_of(".fini", name)
328       || is_prefix_of(".gcc_except_table", name)
329       || is_prefix_of(".jcr", name)
330       || is_prefix_of(".preinit_array", name)
331       || (is_prefix_of(".text", name)
332           && strstr(name, "personality"))
333       || (is_prefix_of(".data", name)
334           && strstr(name, "personality"))
335       || (is_prefix_of(".sdata", name)
336           && strstr(name, "personality"))
337       || (is_prefix_of(".gnu.linkonce.d", name)
338           && strstr(name, "personality")))
339     {
340       return true;
341     }
342   return false;
343 }
344
345 // Finalize the incremental relocation information.  Allocates a block
346 // of relocation entries for each symbol, and sets the reloc_bases_
347 // array to point to the first entry in each block.  If CLEAR_COUNTS
348 // is TRUE, also clear the per-symbol relocation counters.
349
350 void
351 Relobj::finalize_incremental_relocs(Layout* layout, bool clear_counts)
352 {
353   unsigned int nsyms = this->get_global_symbols()->size();
354   this->reloc_bases_ = new unsigned int[nsyms];
355
356   gold_assert(this->reloc_bases_ != NULL);
357   gold_assert(layout->incremental_inputs() != NULL);
358
359   unsigned int rindex = layout->incremental_inputs()->get_reloc_count();
360   for (unsigned int i = 0; i < nsyms; ++i)
361     {
362       this->reloc_bases_[i] = rindex;
363       rindex += this->reloc_counts_[i];
364       if (clear_counts)
365         this->reloc_counts_[i] = 0;
366     }
367   layout->incremental_inputs()->set_reloc_count(rindex);
368 }
369
370 // Class Sized_relobj.
371
372 // Iterate over local symbols, calling a visitor class V for each GOT offset
373 // associated with a local symbol.
374
375 template<int size, bool big_endian>
376 void
377 Sized_relobj<size, big_endian>::do_for_all_local_got_entries(
378     Got_offset_list::Visitor* v) const
379 {
380   unsigned int nsyms = this->local_symbol_count();
381   for (unsigned int i = 0; i < nsyms; i++)
382     {
383       Local_got_offsets::const_iterator p = this->local_got_offsets_.find(i);
384       if (p != this->local_got_offsets_.end())
385         {
386           const Got_offset_list* got_offsets = p->second;
387           got_offsets->for_all_got_offsets(v);
388         }
389     }
390 }
391
392 // Class Sized_relobj_file.
393
394 template<int size, bool big_endian>
395 Sized_relobj_file<size, big_endian>::Sized_relobj_file(
396     const std::string& name,
397     Input_file* input_file,
398     off_t offset,
399     const elfcpp::Ehdr<size, big_endian>& ehdr)
400   : Sized_relobj<size, big_endian>(name, input_file, offset),
401     elf_file_(this, ehdr),
402     symtab_shndx_(-1U),
403     local_symbol_count_(0),
404     output_local_symbol_count_(0),
405     output_local_dynsym_count_(0),
406     symbols_(),
407     defined_count_(0),
408     local_symbol_offset_(0),
409     local_dynsym_offset_(0),
410     local_values_(),
411     local_plt_offsets_(),
412     kept_comdat_sections_(),
413     has_eh_frame_(false),
414     discarded_eh_frame_shndx_(-1U),
415     deferred_layout_(),
416     deferred_layout_relocs_(),
417     compressed_sections_()
418 {
419   this->e_type_ = ehdr.get_e_type();
420 }
421
422 template<int size, bool big_endian>
423 Sized_relobj_file<size, big_endian>::~Sized_relobj_file()
424 {
425 }
426
427 // Set up an object file based on the file header.  This sets up the
428 // section information.
429
430 template<int size, bool big_endian>
431 void
432 Sized_relobj_file<size, big_endian>::do_setup()
433 {
434   const unsigned int shnum = this->elf_file_.shnum();
435   this->set_shnum(shnum);
436 }
437
438 // Find the SHT_SYMTAB section, given the section headers.  The ELF
439 // standard says that maybe in the future there can be more than one
440 // SHT_SYMTAB section.  Until somebody figures out how that could
441 // work, we assume there is only one.
442
443 template<int size, bool big_endian>
444 void
445 Sized_relobj_file<size, big_endian>::find_symtab(const unsigned char* pshdrs)
446 {
447   const unsigned int shnum = this->shnum();
448   this->symtab_shndx_ = 0;
449   if (shnum > 0)
450     {
451       // Look through the sections in reverse order, since gas tends
452       // to put the symbol table at the end.
453       const unsigned char* p = pshdrs + shnum * This::shdr_size;
454       unsigned int i = shnum;
455       unsigned int xindex_shndx = 0;
456       unsigned int xindex_link = 0;
457       while (i > 0)
458         {
459           --i;
460           p -= This::shdr_size;
461           typename This::Shdr shdr(p);
462           if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB)
463             {
464               this->symtab_shndx_ = i;
465               if (xindex_shndx > 0 && xindex_link == i)
466                 {
467                   Xindex* xindex =
468                     new Xindex(this->elf_file_.large_shndx_offset());
469                   xindex->read_symtab_xindex<size, big_endian>(this,
470                                                                xindex_shndx,
471                                                                pshdrs);
472                   this->set_xindex(xindex);
473                 }
474               break;
475             }
476
477           // Try to pick up the SHT_SYMTAB_SHNDX section, if there is
478           // one.  This will work if it follows the SHT_SYMTAB
479           // section.
480           if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX)
481             {
482               xindex_shndx = i;
483               xindex_link = this->adjust_shndx(shdr.get_sh_link());
484             }
485         }
486     }
487 }
488
489 // Return the Xindex structure to use for object with lots of
490 // sections.
491
492 template<int size, bool big_endian>
493 Xindex*
494 Sized_relobj_file<size, big_endian>::do_initialize_xindex()
495 {
496   gold_assert(this->symtab_shndx_ != -1U);
497   Xindex* xindex = new Xindex(this->elf_file_.large_shndx_offset());
498   xindex->initialize_symtab_xindex<size, big_endian>(this, this->symtab_shndx_);
499   return xindex;
500 }
501
502 // Return whether SHDR has the right type and flags to be a GNU
503 // .eh_frame section.
504
505 template<int size, bool big_endian>
506 bool
507 Sized_relobj_file<size, big_endian>::check_eh_frame_flags(
508     const elfcpp::Shdr<size, big_endian>* shdr) const
509 {
510   elfcpp::Elf_Word sh_type = shdr->get_sh_type();
511   return ((sh_type == elfcpp::SHT_PROGBITS
512            || sh_type == elfcpp::SHT_X86_64_UNWIND)
513           && (shdr->get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
514 }
515
516 // Find the section header with the given name.
517
518 template<int size, bool big_endian>
519 const unsigned char*
520 Sized_relobj_file<size, big_endian>::find_shdr(
521     const unsigned char* pshdrs,
522     const char* name,
523     const char* names,
524     section_size_type names_size,
525     const unsigned char* hdr) const
526 {
527   const unsigned int shnum = this->shnum();
528   const unsigned char* hdr_end = pshdrs + This::shdr_size * shnum;
529   size_t sh_name = 0;
530
531   while (1)
532     {
533       if (hdr)
534         {
535           // We found HDR last time we were called, continue looking.
536           typename This::Shdr shdr(hdr);
537           sh_name = shdr.get_sh_name();
538         }
539       else
540         {
541           // Look for the next occurrence of NAME in NAMES.
542           // The fact that .shstrtab produced by current GNU tools is
543           // string merged means we shouldn't have both .not.foo and
544           // .foo in .shstrtab, and multiple .foo sections should all
545           // have the same sh_name.  However, this is not guaranteed
546           // by the ELF spec and not all ELF object file producers may
547           // be so clever.
548           size_t len = strlen(name) + 1;
549           const char *p = sh_name ? names + sh_name + len : names;
550           p = reinterpret_cast<const char*>(memmem(p, names_size - (p - names),
551                                                    name, len));
552           if (p == NULL)
553             return NULL;
554           sh_name = p - names;
555           hdr = pshdrs;
556           if (sh_name == 0)
557             return hdr;
558         }
559
560       hdr += This::shdr_size;
561       while (hdr < hdr_end)
562         {
563           typename This::Shdr shdr(hdr);
564           if (shdr.get_sh_name() == sh_name)
565             return hdr;
566           hdr += This::shdr_size;
567         }
568       hdr = NULL;
569       if (sh_name == 0)
570         return hdr;
571     }
572 }
573
574 // Return whether there is a GNU .eh_frame section, given the section
575 // headers and the section names.
576
577 template<int size, bool big_endian>
578 bool
579 Sized_relobj_file<size, big_endian>::find_eh_frame(
580     const unsigned char* pshdrs,
581     const char* names,
582     section_size_type names_size) const
583 {
584   const unsigned char* s = NULL;
585
586   while (1)
587     {
588       s = this->find_shdr(pshdrs, ".eh_frame", names, names_size, s);
589       if (s == NULL)
590         return false;
591
592       typename This::Shdr shdr(s);
593       if (this->check_eh_frame_flags(&shdr))
594         return true;
595     }
596 }
597
598 // Return TRUE if this is a section whose contents will be needed in the
599 // Add_symbols task.  This function is only called for sections that have
600 // already passed the test in is_compressed_debug_section(), so we know
601 // that the section name begins with ".zdebug".
602
603 static bool
604 need_decompressed_section(const char* name)
605 {
606   // Skip over the ".zdebug" and a quick check for the "_".
607   name += 7;
608   if (*name++ != '_')
609     return false;
610
611 #ifdef ENABLE_THREADS
612   // Decompressing these sections now will help only if we're
613   // multithreaded.
614   if (parameters->options().threads())
615     {
616       // We will need .zdebug_str if this is not an incremental link
617       // (i.e., we are processing string merge sections) or if we need
618       // to build a gdb index.
619       if ((!parameters->incremental() || parameters->options().gdb_index())
620           && strcmp(name, "str") == 0)
621         return true;
622
623       // We will need these other sections when building a gdb index.
624       if (parameters->options().gdb_index()
625           && (strcmp(name, "info") == 0
626               || strcmp(name, "types") == 0
627               || strcmp(name, "pubnames") == 0
628               || strcmp(name, "pubtypes") == 0
629               || strcmp(name, "ranges") == 0
630               || strcmp(name, "abbrev") == 0))
631         return true;
632     }
633 #endif
634
635   // Even when single-threaded, we will need .zdebug_str if this is
636   // not an incremental link and we are building a gdb index.
637   // Otherwise, we would decompress the section twice: once for
638   // string merge processing, and once for building the gdb index.
639   if (!parameters->incremental()
640       && parameters->options().gdb_index()
641       && strcmp(name, "str") == 0)
642     return true;
643
644   return false;
645 }
646
647 // Build a table for any compressed debug sections, mapping each section index
648 // to the uncompressed size and (if needed) the decompressed contents.
649
650 template<int size, bool big_endian>
651 Compressed_section_map*
652 build_compressed_section_map(
653     const unsigned char* pshdrs,
654     unsigned int shnum,
655     const char* names,
656     section_size_type names_size,
657     Sized_relobj_file<size, big_endian>* obj)
658 {
659   Compressed_section_map* uncompressed_map = new Compressed_section_map();
660   const unsigned int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
661   const unsigned char* p = pshdrs + shdr_size;
662
663   for (unsigned int i = 1; i < shnum; ++i, p += shdr_size)
664     {
665       typename elfcpp::Shdr<size, big_endian> shdr(p);
666       if (shdr.get_sh_type() == elfcpp::SHT_PROGBITS
667           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
668         {
669           if (shdr.get_sh_name() >= names_size)
670             {
671               obj->error(_("bad section name offset for section %u: %lu"),
672                          i, static_cast<unsigned long>(shdr.get_sh_name()));
673               continue;
674             }
675
676           const char* name = names + shdr.get_sh_name();
677           if (is_compressed_debug_section(name))
678             {
679               section_size_type len;
680               const unsigned char* contents =
681                   obj->section_contents(i, &len, false);
682               uint64_t uncompressed_size = get_uncompressed_size(contents, len);
683               Compressed_section_info info;
684               info.size = convert_to_section_size_type(uncompressed_size);
685               info.contents = NULL;
686               if (uncompressed_size != -1ULL)
687                 {
688                   unsigned char* uncompressed_data = NULL;
689                   if (need_decompressed_section(name))
690                     {
691                       uncompressed_data = new unsigned char[uncompressed_size];
692                       if (decompress_input_section(contents, len,
693                                                    uncompressed_data,
694                                                    uncompressed_size))
695                         info.contents = uncompressed_data;
696                       else
697                         delete[] uncompressed_data;
698                     }
699                   (*uncompressed_map)[i] = info;
700                 }
701             }
702         }
703     }
704   return uncompressed_map;
705 }
706
707 // Stash away info for a number of special sections.
708 // Return true if any of the sections found require local symbols to be read.
709
710 template<int size, bool big_endian>
711 bool
712 Sized_relobj_file<size, big_endian>::do_find_special_sections(
713     Read_symbols_data* sd)
714 {
715   const unsigned char* const pshdrs = sd->section_headers->data();
716   const unsigned char* namesu = sd->section_names->data();
717   const char* names = reinterpret_cast<const char*>(namesu);
718
719   if (this->find_eh_frame(pshdrs, names, sd->section_names_size))
720     this->has_eh_frame_ = true;
721
722   if (memmem(names, sd->section_names_size, ".zdebug_", 8) != NULL)
723     this->compressed_sections_
724       = build_compressed_section_map(pshdrs, this->shnum(), names,
725                                      sd->section_names_size, this);
726   return (this->has_eh_frame_
727           || (!parameters->options().relocatable()
728               && parameters->options().gdb_index()
729               && (memmem(names, sd->section_names_size, "debug_info", 12) == 0
730                   || memmem(names, sd->section_names_size, "debug_types",
731                             13) == 0)));
732 }
733
734 // Read the sections and symbols from an object file.
735
736 template<int size, bool big_endian>
737 void
738 Sized_relobj_file<size, big_endian>::do_read_symbols(Read_symbols_data* sd)
739 {
740   this->read_section_data(&this->elf_file_, sd);
741
742   const unsigned char* const pshdrs = sd->section_headers->data();
743
744   this->find_symtab(pshdrs);
745
746   bool need_local_symbols = this->do_find_special_sections(sd);
747
748   sd->symbols = NULL;
749   sd->symbols_size = 0;
750   sd->external_symbols_offset = 0;
751   sd->symbol_names = NULL;
752   sd->symbol_names_size = 0;
753
754   if (this->symtab_shndx_ == 0)
755     {
756       // No symbol table.  Weird but legal.
757       return;
758     }
759
760   // Get the symbol table section header.
761   typename This::Shdr symtabshdr(pshdrs
762                                  + this->symtab_shndx_ * This::shdr_size);
763   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
764
765   // If this object has a .eh_frame section, or if building a .gdb_index
766   // section and there is debug info, we need all the symbols.
767   // Otherwise we only need the external symbols.  While it would be
768   // simpler to just always read all the symbols, I've seen object
769   // files with well over 2000 local symbols, which for a 64-bit
770   // object file format is over 5 pages that we don't need to read
771   // now.
772
773   const int sym_size = This::sym_size;
774   const unsigned int loccount = symtabshdr.get_sh_info();
775   this->local_symbol_count_ = loccount;
776   this->local_values_.resize(loccount);
777   section_offset_type locsize = loccount * sym_size;
778   off_t dataoff = symtabshdr.get_sh_offset();
779   section_size_type datasize =
780     convert_to_section_size_type(symtabshdr.get_sh_size());
781   off_t extoff = dataoff + locsize;
782   section_size_type extsize = datasize - locsize;
783
784   off_t readoff = need_local_symbols ? dataoff : extoff;
785   section_size_type readsize = need_local_symbols ? datasize : extsize;
786
787   if (readsize == 0)
788     {
789       // No external symbols.  Also weird but also legal.
790       return;
791     }
792
793   File_view* fvsymtab = this->get_lasting_view(readoff, readsize, true, false);
794
795   // Read the section header for the symbol names.
796   unsigned int strtab_shndx = this->adjust_shndx(symtabshdr.get_sh_link());
797   if (strtab_shndx >= this->shnum())
798     {
799       this->error(_("invalid symbol table name index: %u"), strtab_shndx);
800       return;
801     }
802   typename This::Shdr strtabshdr(pshdrs + strtab_shndx * This::shdr_size);
803   if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB)
804     {
805       this->error(_("symbol table name section has wrong type: %u"),
806                   static_cast<unsigned int>(strtabshdr.get_sh_type()));
807       return;
808     }
809
810   // Read the symbol names.
811   File_view* fvstrtab = this->get_lasting_view(strtabshdr.get_sh_offset(),
812                                                strtabshdr.get_sh_size(),
813                                                false, true);
814
815   sd->symbols = fvsymtab;
816   sd->symbols_size = readsize;
817   sd->external_symbols_offset = need_local_symbols ? locsize : 0;
818   sd->symbol_names = fvstrtab;
819   sd->symbol_names_size =
820     convert_to_section_size_type(strtabshdr.get_sh_size());
821 }
822
823 // Return the section index of symbol SYM.  Set *VALUE to its value in
824 // the object file.  Set *IS_ORDINARY if this is an ordinary section
825 // index, not a special code between SHN_LORESERVE and SHN_HIRESERVE.
826 // Note that for a symbol which is not defined in this object file,
827 // this will set *VALUE to 0 and return SHN_UNDEF; it will not return
828 // the final value of the symbol in the link.
829
830 template<int size, bool big_endian>
831 unsigned int
832 Sized_relobj_file<size, big_endian>::symbol_section_and_value(unsigned int sym,
833                                                               Address* value,
834                                                               bool* is_ordinary)
835 {
836   section_size_type symbols_size;
837   const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
838                                                         &symbols_size,
839                                                         false);
840
841   const size_t count = symbols_size / This::sym_size;
842   gold_assert(sym < count);
843
844   elfcpp::Sym<size, big_endian> elfsym(symbols + sym * This::sym_size);
845   *value = elfsym.get_st_value();
846
847   return this->adjust_sym_shndx(sym, elfsym.get_st_shndx(), is_ordinary);
848 }
849
850 // Return whether to include a section group in the link.  LAYOUT is
851 // used to keep track of which section groups we have already seen.
852 // INDEX is the index of the section group and SHDR is the section
853 // header.  If we do not want to include this group, we set bits in
854 // OMIT for each section which should be discarded.
855
856 template<int size, bool big_endian>
857 bool
858 Sized_relobj_file<size, big_endian>::include_section_group(
859     Symbol_table* symtab,
860     Layout* layout,
861     unsigned int index,
862     const char* name,
863     const unsigned char* shdrs,
864     const char* section_names,
865     section_size_type section_names_size,
866     std::vector<bool>* omit)
867 {
868   // Read the section contents.
869   typename This::Shdr shdr(shdrs + index * This::shdr_size);
870   const unsigned char* pcon = this->get_view(shdr.get_sh_offset(),
871                                              shdr.get_sh_size(), true, false);
872   const elfcpp::Elf_Word* pword =
873     reinterpret_cast<const elfcpp::Elf_Word*>(pcon);
874
875   // The first word contains flags.  We only care about COMDAT section
876   // groups.  Other section groups are always included in the link
877   // just like ordinary sections.
878   elfcpp::Elf_Word flags = elfcpp::Swap<32, big_endian>::readval(pword);
879
880   // Look up the group signature, which is the name of a symbol.  ELF
881   // uses a symbol name because some group signatures are long, and
882   // the name is generally already in the symbol table, so it makes
883   // sense to put the long string just once in .strtab rather than in
884   // both .strtab and .shstrtab.
885
886   // Get the appropriate symbol table header (this will normally be
887   // the single SHT_SYMTAB section, but in principle it need not be).
888   const unsigned int link = this->adjust_shndx(shdr.get_sh_link());
889   typename This::Shdr symshdr(this, this->elf_file_.section_header(link));
890
891   // Read the symbol table entry.
892   unsigned int symndx = shdr.get_sh_info();
893   if (symndx >= symshdr.get_sh_size() / This::sym_size)
894     {
895       this->error(_("section group %u info %u out of range"),
896                   index, symndx);
897       return false;
898     }
899   off_t symoff = symshdr.get_sh_offset() + symndx * This::sym_size;
900   const unsigned char* psym = this->get_view(symoff, This::sym_size, true,
901                                              false);
902   elfcpp::Sym<size, big_endian> sym(psym);
903
904   // Read the symbol table names.
905   section_size_type symnamelen;
906   const unsigned char* psymnamesu;
907   psymnamesu = this->section_contents(this->adjust_shndx(symshdr.get_sh_link()),
908                                       &symnamelen, true);
909   const char* psymnames = reinterpret_cast<const char*>(psymnamesu);
910
911   // Get the section group signature.
912   if (sym.get_st_name() >= symnamelen)
913     {
914       this->error(_("symbol %u name offset %u out of range"),
915                   symndx, sym.get_st_name());
916       return false;
917     }
918
919   std::string signature(psymnames + sym.get_st_name());
920
921   // It seems that some versions of gas will create a section group
922   // associated with a section symbol, and then fail to give a name to
923   // the section symbol.  In such a case, use the name of the section.
924   if (signature[0] == '\0' && sym.get_st_type() == elfcpp::STT_SECTION)
925     {
926       bool is_ordinary;
927       unsigned int sym_shndx = this->adjust_sym_shndx(symndx,
928                                                       sym.get_st_shndx(),
929                                                       &is_ordinary);
930       if (!is_ordinary || sym_shndx >= this->shnum())
931         {
932           this->error(_("symbol %u invalid section index %u"),
933                       symndx, sym_shndx);
934           return false;
935         }
936       typename This::Shdr member_shdr(shdrs + sym_shndx * This::shdr_size);
937       if (member_shdr.get_sh_name() < section_names_size)
938         signature = section_names + member_shdr.get_sh_name();
939     }
940
941   // Record this section group in the layout, and see whether we've already
942   // seen one with the same signature.
943   bool include_group;
944   bool is_comdat;
945   Kept_section* kept_section = NULL;
946
947   if ((flags & elfcpp::GRP_COMDAT) == 0)
948     {
949       include_group = true;
950       is_comdat = false;
951     }
952   else
953     {
954       include_group = layout->find_or_add_kept_section(signature,
955                                                        this, index, true,
956                                                        true, &kept_section);
957       is_comdat = true;
958     }
959
960   if (is_comdat && include_group)
961     {
962       Incremental_inputs* incremental_inputs = layout->incremental_inputs();
963       if (incremental_inputs != NULL)
964         incremental_inputs->report_comdat_group(this, signature.c_str());
965     }
966
967   size_t count = shdr.get_sh_size() / sizeof(elfcpp::Elf_Word);
968
969   std::vector<unsigned int> shndxes;
970   bool relocate_group = include_group && parameters->options().relocatable();
971   if (relocate_group)
972     shndxes.reserve(count - 1);
973
974   for (size_t i = 1; i < count; ++i)
975     {
976       elfcpp::Elf_Word shndx =
977         this->adjust_shndx(elfcpp::Swap<32, big_endian>::readval(pword + i));
978
979       if (relocate_group)
980         shndxes.push_back(shndx);
981
982       if (shndx >= this->shnum())
983         {
984           this->error(_("section %u in section group %u out of range"),
985                       shndx, index);
986           continue;
987         }
988
989       // Check for an earlier section number, since we're going to get
990       // it wrong--we may have already decided to include the section.
991       if (shndx < index)
992         this->error(_("invalid section group %u refers to earlier section %u"),
993                     index, shndx);
994
995       // Get the name of the member section.
996       typename This::Shdr member_shdr(shdrs + shndx * This::shdr_size);
997       if (member_shdr.get_sh_name() >= section_names_size)
998         {
999           // This is an error, but it will be diagnosed eventually
1000           // in do_layout, so we don't need to do anything here but
1001           // ignore it.
1002           continue;
1003         }
1004       std::string mname(section_names + member_shdr.get_sh_name());
1005
1006       if (include_group)
1007         {
1008           if (is_comdat)
1009             kept_section->add_comdat_section(mname, shndx,
1010                                              member_shdr.get_sh_size());
1011         }
1012       else
1013         {
1014           (*omit)[shndx] = true;
1015
1016           if (is_comdat)
1017             {
1018               Relobj* kept_object = kept_section->object();
1019               if (kept_section->is_comdat())
1020                 {
1021                   // Find the corresponding kept section, and store
1022                   // that info in the discarded section table.
1023                   unsigned int kept_shndx;
1024                   uint64_t kept_size;
1025                   if (kept_section->find_comdat_section(mname, &kept_shndx,
1026                                                         &kept_size))
1027                     {
1028                       // We don't keep a mapping for this section if
1029                       // it has a different size.  The mapping is only
1030                       // used for relocation processing, and we don't
1031                       // want to treat the sections as similar if the
1032                       // sizes are different.  Checking the section
1033                       // size is the approach used by the GNU linker.
1034                       if (kept_size == member_shdr.get_sh_size())
1035                         this->set_kept_comdat_section(shndx, kept_object,
1036                                                       kept_shndx);
1037                     }
1038                 }
1039               else
1040                 {
1041                   // The existing section is a linkonce section.  Add
1042                   // a mapping if there is exactly one section in the
1043                   // group (which is true when COUNT == 2) and if it
1044                   // is the same size.
1045                   if (count == 2
1046                       && (kept_section->linkonce_size()
1047                           == member_shdr.get_sh_size()))
1048                     this->set_kept_comdat_section(shndx, kept_object,
1049                                                   kept_section->shndx());
1050                 }
1051             }
1052         }
1053     }
1054
1055   if (relocate_group)
1056     layout->layout_group(symtab, this, index, name, signature.c_str(),
1057                          shdr, flags, &shndxes);
1058
1059   return include_group;
1060 }
1061
1062 // Whether to include a linkonce section in the link.  NAME is the
1063 // name of the section and SHDR is the section header.
1064
1065 // Linkonce sections are a GNU extension implemented in the original
1066 // GNU linker before section groups were defined.  The semantics are
1067 // that we only include one linkonce section with a given name.  The
1068 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
1069 // where T is the type of section and SYMNAME is the name of a symbol.
1070 // In an attempt to make linkonce sections interact well with section
1071 // groups, we try to identify SYMNAME and use it like a section group
1072 // signature.  We want to block section groups with that signature,
1073 // but not other linkonce sections with that signature.  We also use
1074 // the full name of the linkonce section as a normal section group
1075 // signature.
1076
1077 template<int size, bool big_endian>
1078 bool
1079 Sized_relobj_file<size, big_endian>::include_linkonce_section(
1080     Layout* layout,
1081     unsigned int index,
1082     const char* name,
1083     const elfcpp::Shdr<size, big_endian>& shdr)
1084 {
1085   typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
1086   // In general the symbol name we want will be the string following
1087   // the last '.'.  However, we have to handle the case of
1088   // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
1089   // some versions of gcc.  So we use a heuristic: if the name starts
1090   // with ".gnu.linkonce.t.", we use everything after that.  Otherwise
1091   // we look for the last '.'.  We can't always simply skip
1092   // ".gnu.linkonce.X", because we have to deal with cases like
1093   // ".gnu.linkonce.d.rel.ro.local".
1094   const char* const linkonce_t = ".gnu.linkonce.t.";
1095   const char* symname;
1096   if (strncmp(name, linkonce_t, strlen(linkonce_t)) == 0)
1097     symname = name + strlen(linkonce_t);
1098   else
1099     symname = strrchr(name, '.') + 1;
1100   std::string sig1(symname);
1101   std::string sig2(name);
1102   Kept_section* kept1;
1103   Kept_section* kept2;
1104   bool include1 = layout->find_or_add_kept_section(sig1, this, index, false,
1105                                                    false, &kept1);
1106   bool include2 = layout->find_or_add_kept_section(sig2, this, index, false,
1107                                                    true, &kept2);
1108
1109   if (!include2)
1110     {
1111       // We are not including this section because we already saw the
1112       // name of the section as a signature.  This normally implies
1113       // that the kept section is another linkonce section.  If it is
1114       // the same size, record it as the section which corresponds to
1115       // this one.
1116       if (kept2->object() != NULL
1117           && !kept2->is_comdat()
1118           && kept2->linkonce_size() == sh_size)
1119         this->set_kept_comdat_section(index, kept2->object(), kept2->shndx());
1120     }
1121   else if (!include1)
1122     {
1123       // The section is being discarded on the basis of its symbol
1124       // name.  This means that the corresponding kept section was
1125       // part of a comdat group, and it will be difficult to identify
1126       // the specific section within that group that corresponds to
1127       // this linkonce section.  We'll handle the simple case where
1128       // the group has only one member section.  Otherwise, it's not
1129       // worth the effort.
1130       unsigned int kept_shndx;
1131       uint64_t kept_size;
1132       if (kept1->object() != NULL
1133           && kept1->is_comdat()
1134           && kept1->find_single_comdat_section(&kept_shndx, &kept_size)
1135           && kept_size == sh_size)
1136         this->set_kept_comdat_section(index, kept1->object(), kept_shndx);
1137     }
1138   else
1139     {
1140       kept1->set_linkonce_size(sh_size);
1141       kept2->set_linkonce_size(sh_size);
1142     }
1143
1144   return include1 && include2;
1145 }
1146
1147 // Layout an input section.
1148
1149 template<int size, bool big_endian>
1150 inline void
1151 Sized_relobj_file<size, big_endian>::layout_section(
1152     Layout* layout,
1153     unsigned int shndx,
1154     const char* name,
1155     const typename This::Shdr& shdr,
1156     unsigned int reloc_shndx,
1157     unsigned int reloc_type)
1158 {
1159   off_t offset;
1160   Output_section* os = layout->layout(this, shndx, name, shdr,
1161                                           reloc_shndx, reloc_type, &offset);
1162
1163   this->output_sections()[shndx] = os;
1164   if (offset == -1)
1165     this->section_offsets()[shndx] = invalid_address;
1166   else
1167     this->section_offsets()[shndx] = convert_types<Address, off_t>(offset);
1168
1169   // If this section requires special handling, and if there are
1170   // relocs that apply to it, then we must do the special handling
1171   // before we apply the relocs.
1172   if (offset == -1 && reloc_shndx != 0)
1173     this->set_relocs_must_follow_section_writes();
1174 }
1175
1176 // Layout an input .eh_frame section.
1177
1178 template<int size, bool big_endian>
1179 void
1180 Sized_relobj_file<size, big_endian>::layout_eh_frame_section(
1181     Layout* layout,
1182     const unsigned char* symbols_data,
1183     section_size_type symbols_size,
1184     const unsigned char* symbol_names_data,
1185     section_size_type symbol_names_size,
1186     unsigned int shndx,
1187     const typename This::Shdr& shdr,
1188     unsigned int reloc_shndx,
1189     unsigned int reloc_type)
1190 {
1191   gold_assert(this->has_eh_frame_);
1192
1193   off_t offset;
1194   Output_section* os = layout->layout_eh_frame(this,
1195                                                symbols_data,
1196                                                symbols_size,
1197                                                symbol_names_data,
1198                                                symbol_names_size,
1199                                                shndx,
1200                                                shdr,
1201                                                reloc_shndx,
1202                                                reloc_type,
1203                                                &offset);
1204   this->output_sections()[shndx] = os;
1205   if (os == NULL || offset == -1)
1206     {
1207       // An object can contain at most one section holding exception
1208       // frame information.
1209       gold_assert(this->discarded_eh_frame_shndx_ == -1U);
1210       this->discarded_eh_frame_shndx_ = shndx;
1211       this->section_offsets()[shndx] = invalid_address;
1212     }
1213   else
1214     this->section_offsets()[shndx] = convert_types<Address, off_t>(offset);
1215
1216   // If this section requires special handling, and if there are
1217   // relocs that aply to it, then we must do the special handling
1218   // before we apply the relocs.
1219   if (os != NULL && offset == -1 && reloc_shndx != 0)
1220     this->set_relocs_must_follow_section_writes();
1221 }
1222
1223 // Lay out the input sections.  We walk through the sections and check
1224 // whether they should be included in the link.  If they should, we
1225 // pass them to the Layout object, which will return an output section
1226 // and an offset.
1227 // This function is called twice sometimes, two passes, when mapping
1228 // of input sections to output sections must be delayed.
1229 // This is true for the following :
1230 // * Garbage collection (--gc-sections): Some input sections will be
1231 // discarded and hence the assignment must wait until the second pass.
1232 // In the first pass,  it is for setting up some sections as roots to
1233 // a work-list for --gc-sections and to do comdat processing.
1234 // * Identical Code Folding (--icf=<safe,all>): Some input sections
1235 // will be folded and hence the assignment must wait.
1236 // * Using plugins to map some sections to unique segments: Mapping
1237 // some sections to unique segments requires mapping them to unique
1238 // output sections too.  This can be done via plugins now and this
1239 // information is not available in the first pass.
1240
1241 template<int size, bool big_endian>
1242 void
1243 Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
1244                                                Layout* layout,
1245                                                Read_symbols_data* sd)
1246 {
1247   const unsigned int shnum = this->shnum();
1248
1249   /* Should this function be called twice?  */
1250   bool is_two_pass = (parameters->options().gc_sections()
1251                       || parameters->options().icf_enabled()
1252                       || layout->is_unique_segment_for_sections_specified());
1253
1254   /* Only one of is_pass_one and is_pass_two is true.  Both are false when
1255      a two-pass approach is not needed.  */
1256   bool is_pass_one = false;
1257   bool is_pass_two = false;
1258
1259   Symbols_data* gc_sd = NULL;
1260
1261   /* Check if do_layout needs to be two-pass.  If so, find out which pass
1262      should happen.  In the first pass, the data in sd is saved to be used
1263      later in the second pass.  */
1264   if (is_two_pass)
1265     {
1266       gc_sd = this->get_symbols_data();
1267       if (gc_sd == NULL)
1268         {
1269           gold_assert(sd != NULL);
1270           is_pass_one = true;
1271         }
1272       else
1273         {
1274           if (parameters->options().gc_sections())
1275             gold_assert(symtab->gc()->is_worklist_ready());
1276           if (parameters->options().icf_enabled())
1277             gold_assert(symtab->icf()->is_icf_ready()); 
1278           is_pass_two = true;
1279         }
1280     }
1281     
1282   if (shnum == 0)
1283     return;
1284
1285   if (is_pass_one)
1286     {
1287       // During garbage collection save the symbols data to use it when
1288       // re-entering this function.
1289       gc_sd = new Symbols_data;
1290       this->copy_symbols_data(gc_sd, sd, This::shdr_size * shnum);
1291       this->set_symbols_data(gc_sd);
1292     }
1293
1294   const unsigned char* section_headers_data = NULL;
1295   section_size_type section_names_size;
1296   const unsigned char* symbols_data = NULL;
1297   section_size_type symbols_size;
1298   const unsigned char* symbol_names_data = NULL;
1299   section_size_type symbol_names_size;
1300
1301   if (is_two_pass)
1302     {
1303       section_headers_data = gc_sd->section_headers_data;
1304       section_names_size = gc_sd->section_names_size;
1305       symbols_data = gc_sd->symbols_data;
1306       symbols_size = gc_sd->symbols_size;
1307       symbol_names_data = gc_sd->symbol_names_data;
1308       symbol_names_size = gc_sd->symbol_names_size;
1309     }
1310   else
1311     {
1312       section_headers_data = sd->section_headers->data();
1313       section_names_size = sd->section_names_size;
1314       if (sd->symbols != NULL)
1315         symbols_data = sd->symbols->data();
1316       symbols_size = sd->symbols_size;
1317       if (sd->symbol_names != NULL)
1318         symbol_names_data = sd->symbol_names->data();
1319       symbol_names_size = sd->symbol_names_size;
1320     }
1321
1322   // Get the section headers.
1323   const unsigned char* shdrs = section_headers_data;
1324   const unsigned char* pshdrs;
1325
1326   // Get the section names.
1327   const unsigned char* pnamesu = (is_two_pass
1328                                   ? gc_sd->section_names_data
1329                                   : sd->section_names->data());
1330
1331   const char* pnames = reinterpret_cast<const char*>(pnamesu);
1332
1333   // If any input files have been claimed by plugins, we need to defer
1334   // actual layout until the replacement files have arrived.
1335   const bool should_defer_layout =
1336       (parameters->options().has_plugins()
1337        && parameters->options().plugins()->should_defer_layout());
1338   unsigned int num_sections_to_defer = 0;
1339
1340   // For each section, record the index of the reloc section if any.
1341   // Use 0 to mean that there is no reloc section, -1U to mean that
1342   // there is more than one.
1343   std::vector<unsigned int> reloc_shndx(shnum, 0);
1344   std::vector<unsigned int> reloc_type(shnum, elfcpp::SHT_NULL);
1345   // Skip the first, dummy, section.
1346   pshdrs = shdrs + This::shdr_size;
1347   for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1348     {
1349       typename This::Shdr shdr(pshdrs);
1350
1351       // Count the number of sections whose layout will be deferred.
1352       if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1353         ++num_sections_to_defer;
1354
1355       unsigned int sh_type = shdr.get_sh_type();
1356       if (sh_type == elfcpp::SHT_REL || sh_type == elfcpp::SHT_RELA)
1357         {
1358           unsigned int target_shndx = this->adjust_shndx(shdr.get_sh_info());
1359           if (target_shndx == 0 || target_shndx >= shnum)
1360             {
1361               this->error(_("relocation section %u has bad info %u"),
1362                           i, target_shndx);
1363               continue;
1364             }
1365
1366           if (reloc_shndx[target_shndx] != 0)
1367             reloc_shndx[target_shndx] = -1U;
1368           else
1369             {
1370               reloc_shndx[target_shndx] = i;
1371               reloc_type[target_shndx] = sh_type;
1372             }
1373         }
1374     }
1375
1376   Output_sections& out_sections(this->output_sections());
1377   std::vector<Address>& out_section_offsets(this->section_offsets());
1378
1379   if (!is_pass_two)
1380     {
1381       out_sections.resize(shnum);
1382       out_section_offsets.resize(shnum);
1383     }
1384
1385   // If we are only linking for symbols, then there is nothing else to
1386   // do here.
1387   if (this->input_file()->just_symbols())
1388     {
1389       if (!is_pass_two)
1390         {
1391           delete sd->section_headers;
1392           sd->section_headers = NULL;
1393           delete sd->section_names;
1394           sd->section_names = NULL;
1395         }
1396       return;
1397     }
1398
1399   if (num_sections_to_defer > 0)
1400     {
1401       parameters->options().plugins()->add_deferred_layout_object(this);
1402       this->deferred_layout_.reserve(num_sections_to_defer);
1403     }
1404
1405   // Whether we've seen a .note.GNU-stack section.
1406   bool seen_gnu_stack = false;
1407   // The flags of a .note.GNU-stack section.
1408   uint64_t gnu_stack_flags = 0;
1409
1410   // Keep track of which sections to omit.
1411   std::vector<bool> omit(shnum, false);
1412
1413   // Keep track of reloc sections when emitting relocations.
1414   const bool relocatable = parameters->options().relocatable();
1415   const bool emit_relocs = (relocatable
1416                             || parameters->options().emit_relocs());
1417   std::vector<unsigned int> reloc_sections;
1418
1419   // Keep track of .eh_frame sections.
1420   std::vector<unsigned int> eh_frame_sections;
1421
1422   // Keep track of .debug_info and .debug_types sections.
1423   std::vector<unsigned int> debug_info_sections;
1424   std::vector<unsigned int> debug_types_sections;
1425
1426   // Skip the first, dummy, section.
1427   pshdrs = shdrs + This::shdr_size;
1428   for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1429     {
1430       typename This::Shdr shdr(pshdrs);
1431
1432       if (shdr.get_sh_name() >= section_names_size)
1433         {
1434           this->error(_("bad section name offset for section %u: %lu"),
1435                       i, static_cast<unsigned long>(shdr.get_sh_name()));
1436           return;
1437         }
1438
1439       const char* name = pnames + shdr.get_sh_name();
1440
1441       if (!is_pass_two)
1442         {
1443           if (this->handle_gnu_warning_section(name, i, symtab))
1444             {
1445               if (!relocatable && !parameters->options().shared())
1446                 omit[i] = true;
1447             }
1448
1449           // The .note.GNU-stack section is special.  It gives the
1450           // protection flags that this object file requires for the stack
1451           // in memory.
1452           if (strcmp(name, ".note.GNU-stack") == 0)
1453             {
1454               seen_gnu_stack = true;
1455               gnu_stack_flags |= shdr.get_sh_flags();
1456               omit[i] = true;
1457             }
1458
1459           // The .note.GNU-split-stack section is also special.  It
1460           // indicates that the object was compiled with
1461           // -fsplit-stack.
1462           if (this->handle_split_stack_section(name))
1463             {
1464               if (!relocatable && !parameters->options().shared())
1465                 omit[i] = true;
1466             }
1467
1468           // Skip attributes section.
1469           if (parameters->target().is_attributes_section(name))
1470             {
1471               omit[i] = true;
1472             }
1473
1474           bool discard = omit[i];
1475           if (!discard)
1476             {
1477               if (shdr.get_sh_type() == elfcpp::SHT_GROUP)
1478                 {
1479                   if (!this->include_section_group(symtab, layout, i, name,
1480                                                    shdrs, pnames,
1481                                                    section_names_size,
1482                                                    &omit))
1483                     discard = true;
1484                 }
1485               else if ((shdr.get_sh_flags() & elfcpp::SHF_GROUP) == 0
1486                        && Layout::is_linkonce(name))
1487                 {
1488                   if (!this->include_linkonce_section(layout, i, name, shdr))
1489                     discard = true;
1490                 }
1491             }
1492
1493           // Add the section to the incremental inputs layout.
1494           Incremental_inputs* incremental_inputs = layout->incremental_inputs();
1495           if (incremental_inputs != NULL
1496               && !discard
1497               && can_incremental_update(shdr.get_sh_type()))
1498             {
1499               off_t sh_size = shdr.get_sh_size();
1500               section_size_type uncompressed_size;
1501               if (this->section_is_compressed(i, &uncompressed_size))
1502                 sh_size = uncompressed_size;
1503               incremental_inputs->report_input_section(this, i, name, sh_size);
1504             }
1505
1506           if (discard)
1507             {
1508               // Do not include this section in the link.
1509               out_sections[i] = NULL;
1510               out_section_offsets[i] = invalid_address;
1511               continue;
1512             }
1513         }
1514
1515       if (is_pass_one && parameters->options().gc_sections())
1516         {
1517           if (this->is_section_name_included(name)
1518               || layout->keep_input_section (this, name)
1519               || shdr.get_sh_type() == elfcpp::SHT_INIT_ARRAY
1520               || shdr.get_sh_type() == elfcpp::SHT_FINI_ARRAY)
1521             {
1522               symtab->gc()->worklist().push(Section_id(this, i));
1523             }
1524           // If the section name XXX can be represented as a C identifier
1525           // it cannot be discarded if there are references to
1526           // __start_XXX and __stop_XXX symbols.  These need to be
1527           // specially handled.
1528           if (is_cident(name))
1529             {
1530               symtab->gc()->add_cident_section(name, Section_id(this, i));
1531             }
1532         }
1533
1534       // When doing a relocatable link we are going to copy input
1535       // reloc sections into the output.  We only want to copy the
1536       // ones associated with sections which are not being discarded.
1537       // However, we don't know that yet for all sections.  So save
1538       // reloc sections and process them later. Garbage collection is
1539       // not triggered when relocatable code is desired.
1540       if (emit_relocs
1541           && (shdr.get_sh_type() == elfcpp::SHT_REL
1542               || shdr.get_sh_type() == elfcpp::SHT_RELA))
1543         {
1544           reloc_sections.push_back(i);
1545           continue;
1546         }
1547
1548       if (relocatable && shdr.get_sh_type() == elfcpp::SHT_GROUP)
1549         continue;
1550
1551       // The .eh_frame section is special.  It holds exception frame
1552       // information that we need to read in order to generate the
1553       // exception frame header.  We process these after all the other
1554       // sections so that the exception frame reader can reliably
1555       // determine which sections are being discarded, and discard the
1556       // corresponding information.
1557       if (!relocatable
1558           && strcmp(name, ".eh_frame") == 0
1559           && this->check_eh_frame_flags(&shdr))
1560         {
1561           if (is_pass_one)
1562             {
1563               out_sections[i] = reinterpret_cast<Output_section*>(1);
1564               out_section_offsets[i] = invalid_address;
1565             }
1566           else if (should_defer_layout)
1567             this->deferred_layout_.push_back(Deferred_layout(i, name,
1568                                                              pshdrs,
1569                                                              reloc_shndx[i],
1570                                                              reloc_type[i]));
1571           else
1572             eh_frame_sections.push_back(i);
1573           continue;
1574         }
1575
1576       if (is_pass_two && parameters->options().gc_sections())
1577         {
1578           // This is executed during the second pass of garbage
1579           // collection. do_layout has been called before and some
1580           // sections have been already discarded. Simply ignore
1581           // such sections this time around.
1582           if (out_sections[i] == NULL)
1583             {
1584               gold_assert(out_section_offsets[i] == invalid_address);
1585               continue;
1586             }
1587           if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1588               && symtab->gc()->is_section_garbage(this, i))
1589               {
1590                 if (parameters->options().print_gc_sections())
1591                   gold_info(_("%s: removing unused section from '%s'"
1592                               " in file '%s'"),
1593                             program_name, this->section_name(i).c_str(),
1594                             this->name().c_str());
1595                 out_sections[i] = NULL;
1596                 out_section_offsets[i] = invalid_address;
1597                 continue;
1598               }
1599         }
1600
1601       if (is_pass_two && parameters->options().icf_enabled())
1602         {
1603           if (out_sections[i] == NULL)
1604             {
1605               gold_assert(out_section_offsets[i] == invalid_address);
1606               continue;
1607             }
1608           if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1609               && symtab->icf()->is_section_folded(this, i))
1610               {
1611                 if (parameters->options().print_icf_sections())
1612                   {
1613                     Section_id folded =
1614                                 symtab->icf()->get_folded_section(this, i);
1615                     Relobj* folded_obj =
1616                                 reinterpret_cast<Relobj*>(folded.first);
1617                     gold_info(_("%s: ICF folding section '%s' in file '%s'"
1618                                 "into '%s' in file '%s'"),
1619                               program_name, this->section_name(i).c_str(),
1620                               this->name().c_str(),
1621                               folded_obj->section_name(folded.second).c_str(),
1622                               folded_obj->name().c_str());
1623                   }
1624                 out_sections[i] = NULL;
1625                 out_section_offsets[i] = invalid_address;
1626                 continue;
1627               }
1628         }
1629
1630       // Defer layout here if input files are claimed by plugins.  When gc
1631       // is turned on this function is called twice.  For the second call
1632       // should_defer_layout should be false.
1633       if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1634         {
1635           gold_assert(!is_pass_two);
1636           this->deferred_layout_.push_back(Deferred_layout(i, name,
1637                                                            pshdrs,
1638                                                            reloc_shndx[i],
1639                                                            reloc_type[i]));
1640           // Put dummy values here; real values will be supplied by
1641           // do_layout_deferred_sections.
1642           out_sections[i] = reinterpret_cast<Output_section*>(2);
1643           out_section_offsets[i] = invalid_address;
1644           continue;
1645         }
1646
1647       // During gc_pass_two if a section that was previously deferred is
1648       // found, do not layout the section as layout_deferred_sections will
1649       // do it later from gold.cc.
1650       if (is_pass_two
1651           && (out_sections[i] == reinterpret_cast<Output_section*>(2)))
1652         continue;
1653
1654       if (is_pass_one)
1655         {
1656           // This is during garbage collection. The out_sections are
1657           // assigned in the second call to this function.
1658           out_sections[i] = reinterpret_cast<Output_section*>(1);
1659           out_section_offsets[i] = invalid_address;
1660         }
1661       else
1662         {
1663           // When garbage collection is switched on the actual layout
1664           // only happens in the second call.
1665           this->layout_section(layout, i, name, shdr, reloc_shndx[i],
1666                                reloc_type[i]);
1667
1668           // When generating a .gdb_index section, we do additional
1669           // processing of .debug_info and .debug_types sections after all
1670           // the other sections for the same reason as above.
1671           if (!relocatable
1672               && parameters->options().gdb_index()
1673               && !(shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1674             {
1675               if (strcmp(name, ".debug_info") == 0
1676                   || strcmp(name, ".zdebug_info") == 0)
1677                 debug_info_sections.push_back(i);
1678               else if (strcmp(name, ".debug_types") == 0
1679                        || strcmp(name, ".zdebug_types") == 0)
1680                 debug_types_sections.push_back(i);
1681             }
1682         }
1683     }
1684
1685   if (!is_pass_two)
1686     layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags, this);
1687
1688   // When doing a relocatable link handle the reloc sections at the
1689   // end.  Garbage collection  and Identical Code Folding is not
1690   // turned on for relocatable code.
1691   if (emit_relocs)
1692     this->size_relocatable_relocs();
1693
1694   gold_assert(!is_two_pass || reloc_sections.empty());
1695
1696   for (std::vector<unsigned int>::const_iterator p = reloc_sections.begin();
1697        p != reloc_sections.end();
1698        ++p)
1699     {
1700       unsigned int i = *p;
1701       const unsigned char* pshdr;
1702       pshdr = section_headers_data + i * This::shdr_size;
1703       typename This::Shdr shdr(pshdr);
1704
1705       unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1706       if (data_shndx >= shnum)
1707         {
1708           // We already warned about this above.
1709           continue;
1710         }
1711
1712       Output_section* data_section = out_sections[data_shndx];
1713       if (data_section == reinterpret_cast<Output_section*>(2))
1714         {
1715           // The layout for the data section was deferred, so we need
1716           // to defer the relocation section, too.
1717           const char* name = pnames + shdr.get_sh_name();
1718           this->deferred_layout_relocs_.push_back(
1719               Deferred_layout(i, name, pshdr, 0, elfcpp::SHT_NULL));
1720           out_sections[i] = reinterpret_cast<Output_section*>(2);
1721           out_section_offsets[i] = invalid_address;
1722           continue;
1723         }
1724       if (data_section == NULL)
1725         {
1726           out_sections[i] = NULL;
1727           out_section_offsets[i] = invalid_address;
1728           continue;
1729         }
1730
1731       Relocatable_relocs* rr = new Relocatable_relocs();
1732       this->set_relocatable_relocs(i, rr);
1733
1734       Output_section* os = layout->layout_reloc(this, i, shdr, data_section,
1735                                                 rr);
1736       out_sections[i] = os;
1737       out_section_offsets[i] = invalid_address;
1738     }
1739
1740   // Handle the .eh_frame sections at the end.
1741   gold_assert(!is_pass_one || eh_frame_sections.empty());
1742   for (std::vector<unsigned int>::const_iterator p = eh_frame_sections.begin();
1743        p != eh_frame_sections.end();
1744        ++p)
1745     {
1746       unsigned int i = *p;
1747       const unsigned char* pshdr;
1748       pshdr = section_headers_data + i * This::shdr_size;
1749       typename This::Shdr shdr(pshdr);
1750
1751       this->layout_eh_frame_section(layout,
1752                                     symbols_data,
1753                                     symbols_size,
1754                                     symbol_names_data,
1755                                     symbol_names_size,
1756                                     i,
1757                                     shdr,
1758                                     reloc_shndx[i],
1759                                     reloc_type[i]);
1760     }
1761
1762   // When building a .gdb_index section, scan the .debug_info and
1763   // .debug_types sections.
1764   gold_assert(!is_pass_one
1765               || (debug_info_sections.empty() && debug_types_sections.empty()));
1766   for (std::vector<unsigned int>::const_iterator p
1767            = debug_info_sections.begin();
1768        p != debug_info_sections.end();
1769        ++p)
1770     {
1771       unsigned int i = *p;
1772       layout->add_to_gdb_index(false, this, symbols_data, symbols_size,
1773                                i, reloc_shndx[i], reloc_type[i]);
1774     }
1775   for (std::vector<unsigned int>::const_iterator p
1776            = debug_types_sections.begin();
1777        p != debug_types_sections.end();
1778        ++p)
1779     {
1780       unsigned int i = *p;
1781       layout->add_to_gdb_index(true, this, symbols_data, symbols_size,
1782                                i, reloc_shndx[i], reloc_type[i]);
1783     }
1784
1785   if (is_pass_two)
1786     {
1787       delete[] gc_sd->section_headers_data;
1788       delete[] gc_sd->section_names_data;
1789       delete[] gc_sd->symbols_data;
1790       delete[] gc_sd->symbol_names_data;
1791       this->set_symbols_data(NULL);
1792     }
1793   else
1794     {
1795       delete sd->section_headers;
1796       sd->section_headers = NULL;
1797       delete sd->section_names;
1798       sd->section_names = NULL;
1799     }
1800 }
1801
1802 // Layout sections whose layout was deferred while waiting for
1803 // input files from a plugin.
1804
1805 template<int size, bool big_endian>
1806 void
1807 Sized_relobj_file<size, big_endian>::do_layout_deferred_sections(Layout* layout)
1808 {
1809   typename std::vector<Deferred_layout>::iterator deferred;
1810
1811   for (deferred = this->deferred_layout_.begin();
1812        deferred != this->deferred_layout_.end();
1813        ++deferred)
1814     {
1815       typename This::Shdr shdr(deferred->shdr_data_);
1816       // If the section is not included, it is because the garbage collector
1817       // decided it is not needed.  Avoid reverting that decision.
1818       if (!this->is_section_included(deferred->shndx_))
1819         continue;
1820
1821       if (parameters->options().relocatable()
1822           || deferred->name_ != ".eh_frame"
1823           || !this->check_eh_frame_flags(&shdr))
1824         this->layout_section(layout, deferred->shndx_, deferred->name_.c_str(),
1825                              shdr, deferred->reloc_shndx_,
1826                              deferred->reloc_type_);
1827       else
1828         {
1829           // Reading the symbols again here may be slow.
1830           Read_symbols_data sd;
1831           this->read_symbols(&sd);
1832           this->layout_eh_frame_section(layout,
1833                                         sd.symbols->data(),
1834                                         sd.symbols_size,
1835                                         sd.symbol_names->data(),
1836                                         sd.symbol_names_size,
1837                                         deferred->shndx_,
1838                                         shdr,
1839                                         deferred->reloc_shndx_,
1840                                         deferred->reloc_type_);
1841         }
1842     }
1843
1844   this->deferred_layout_.clear();
1845
1846   // Now handle the deferred relocation sections.
1847
1848   Output_sections& out_sections(this->output_sections());
1849   std::vector<Address>& out_section_offsets(this->section_offsets());
1850
1851   for (deferred = this->deferred_layout_relocs_.begin();
1852        deferred != this->deferred_layout_relocs_.end();
1853        ++deferred)
1854     {
1855       unsigned int shndx = deferred->shndx_;
1856       typename This::Shdr shdr(deferred->shdr_data_);
1857       unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1858
1859       Output_section* data_section = out_sections[data_shndx];
1860       if (data_section == NULL)
1861         {
1862           out_sections[shndx] = NULL;
1863           out_section_offsets[shndx] = invalid_address;
1864           continue;
1865         }
1866
1867       Relocatable_relocs* rr = new Relocatable_relocs();
1868       this->set_relocatable_relocs(shndx, rr);
1869
1870       Output_section* os = layout->layout_reloc(this, shndx, shdr,
1871                                                 data_section, rr);
1872       out_sections[shndx] = os;
1873       out_section_offsets[shndx] = invalid_address;
1874     }
1875 }
1876
1877 // Add the symbols to the symbol table.
1878
1879 template<int size, bool big_endian>
1880 void
1881 Sized_relobj_file<size, big_endian>::do_add_symbols(Symbol_table* symtab,
1882                                                     Read_symbols_data* sd,
1883                                                     Layout*)
1884 {
1885   if (sd->symbols == NULL)
1886     {
1887       gold_assert(sd->symbol_names == NULL);
1888       return;
1889     }
1890
1891   const int sym_size = This::sym_size;
1892   size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1893                      / sym_size);
1894   if (symcount * sym_size != sd->symbols_size - sd->external_symbols_offset)
1895     {
1896       this->error(_("size of symbols is not multiple of symbol size"));
1897       return;
1898     }
1899
1900   this->symbols_.resize(symcount);
1901
1902   const char* sym_names =
1903     reinterpret_cast<const char*>(sd->symbol_names->data());
1904   symtab->add_from_relobj(this,
1905                           sd->symbols->data() + sd->external_symbols_offset,
1906                           symcount, this->local_symbol_count_,
1907                           sym_names, sd->symbol_names_size,
1908                           &this->symbols_,
1909                           &this->defined_count_);
1910
1911   delete sd->symbols;
1912   sd->symbols = NULL;
1913   delete sd->symbol_names;
1914   sd->symbol_names = NULL;
1915 }
1916
1917 // Find out if this object, that is a member of a lib group, should be included
1918 // in the link. We check every symbol defined by this object. If the symbol
1919 // table has a strong undefined reference to that symbol, we have to include
1920 // the object.
1921
1922 template<int size, bool big_endian>
1923 Archive::Should_include
1924 Sized_relobj_file<size, big_endian>::do_should_include_member(
1925     Symbol_table* symtab,
1926     Layout* layout,
1927     Read_symbols_data* sd,
1928     std::string* why)
1929 {
1930   char* tmpbuf = NULL;
1931   size_t tmpbuflen = 0;
1932   const char* sym_names =
1933       reinterpret_cast<const char*>(sd->symbol_names->data());
1934   const unsigned char* syms =
1935       sd->symbols->data() + sd->external_symbols_offset;
1936   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1937   size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1938                          / sym_size);
1939
1940   const unsigned char* p = syms;
1941
1942   for (size_t i = 0; i < symcount; ++i, p += sym_size)
1943     {
1944       elfcpp::Sym<size, big_endian> sym(p);
1945       unsigned int st_shndx = sym.get_st_shndx();
1946       if (st_shndx == elfcpp::SHN_UNDEF)
1947         continue;
1948
1949       unsigned int st_name = sym.get_st_name();
1950       const char* name = sym_names + st_name;
1951       Symbol* symbol;
1952       Archive::Should_include t = Archive::should_include_member(symtab,
1953                                                                  layout,
1954                                                                  name,
1955                                                                  &symbol, why,
1956                                                                  &tmpbuf,
1957                                                                  &tmpbuflen);
1958       if (t == Archive::SHOULD_INCLUDE_YES)
1959         {
1960           if (tmpbuf != NULL)
1961             free(tmpbuf);
1962           return t;
1963         }
1964     }
1965   if (tmpbuf != NULL)
1966     free(tmpbuf);
1967   return Archive::SHOULD_INCLUDE_UNKNOWN;
1968 }
1969
1970 // Iterate over global defined symbols, calling a visitor class V for each.
1971
1972 template<int size, bool big_endian>
1973 void
1974 Sized_relobj_file<size, big_endian>::do_for_all_global_symbols(
1975     Read_symbols_data* sd,
1976     Library_base::Symbol_visitor_base* v)
1977 {
1978   const char* sym_names =
1979       reinterpret_cast<const char*>(sd->symbol_names->data());
1980   const unsigned char* syms =
1981       sd->symbols->data() + sd->external_symbols_offset;
1982   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1983   size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1984                      / sym_size);
1985   const unsigned char* p = syms;
1986
1987   for (size_t i = 0; i < symcount; ++i, p += sym_size)
1988     {
1989       elfcpp::Sym<size, big_endian> sym(p);
1990       if (sym.get_st_shndx() != elfcpp::SHN_UNDEF)
1991         v->visit(sym_names + sym.get_st_name());
1992     }
1993 }
1994
1995 // Return whether the local symbol SYMNDX has a PLT offset.
1996
1997 template<int size, bool big_endian>
1998 bool
1999 Sized_relobj_file<size, big_endian>::local_has_plt_offset(
2000     unsigned int symndx) const
2001 {
2002   typename Local_plt_offsets::const_iterator p =
2003     this->local_plt_offsets_.find(symndx);
2004   return p != this->local_plt_offsets_.end();
2005 }
2006
2007 // Get the PLT offset of a local symbol.
2008
2009 template<int size, bool big_endian>
2010 unsigned int
2011 Sized_relobj_file<size, big_endian>::do_local_plt_offset(
2012     unsigned int symndx) const
2013 {
2014   typename Local_plt_offsets::const_iterator p =
2015     this->local_plt_offsets_.find(symndx);
2016   gold_assert(p != this->local_plt_offsets_.end());
2017   return p->second;
2018 }
2019
2020 // Set the PLT offset of a local symbol.
2021
2022 template<int size, bool big_endian>
2023 void
2024 Sized_relobj_file<size, big_endian>::set_local_plt_offset(
2025     unsigned int symndx, unsigned int plt_offset)
2026 {
2027   std::pair<typename Local_plt_offsets::iterator, bool> ins =
2028     this->local_plt_offsets_.insert(std::make_pair(symndx, plt_offset));
2029   gold_assert(ins.second);
2030 }
2031
2032 // First pass over the local symbols.  Here we add their names to
2033 // *POOL and *DYNPOOL, and we store the symbol value in
2034 // THIS->LOCAL_VALUES_.  This function is always called from a
2035 // singleton thread.  This is followed by a call to
2036 // finalize_local_symbols.
2037
2038 template<int size, bool big_endian>
2039 void
2040 Sized_relobj_file<size, big_endian>::do_count_local_symbols(Stringpool* pool,
2041                                                             Stringpool* dynpool)
2042 {
2043   gold_assert(this->symtab_shndx_ != -1U);
2044   if (this->symtab_shndx_ == 0)
2045     {
2046       // This object has no symbols.  Weird but legal.
2047       return;
2048     }
2049
2050   // Read the symbol table section header.
2051   const unsigned int symtab_shndx = this->symtab_shndx_;
2052   typename This::Shdr symtabshdr(this,
2053                                  this->elf_file_.section_header(symtab_shndx));
2054   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
2055
2056   // Read the local symbols.
2057   const int sym_size = This::sym_size;
2058   const unsigned int loccount = this->local_symbol_count_;
2059   gold_assert(loccount == symtabshdr.get_sh_info());
2060   off_t locsize = loccount * sym_size;
2061   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
2062                                               locsize, true, true);
2063
2064   // Read the symbol names.
2065   const unsigned int strtab_shndx =
2066     this->adjust_shndx(symtabshdr.get_sh_link());
2067   section_size_type strtab_size;
2068   const unsigned char* pnamesu = this->section_contents(strtab_shndx,
2069                                                         &strtab_size,
2070                                                         true);
2071   const char* pnames = reinterpret_cast<const char*>(pnamesu);
2072
2073   // Loop over the local symbols.
2074
2075   const Output_sections& out_sections(this->output_sections());
2076   unsigned int shnum = this->shnum();
2077   unsigned int count = 0;
2078   unsigned int dyncount = 0;
2079   // Skip the first, dummy, symbol.
2080   psyms += sym_size;
2081   bool strip_all = parameters->options().strip_all();
2082   bool discard_all = parameters->options().discard_all();
2083   bool discard_locals = parameters->options().discard_locals();
2084   for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
2085     {
2086       elfcpp::Sym<size, big_endian> sym(psyms);
2087
2088       Symbol_value<size>& lv(this->local_values_[i]);
2089
2090       bool is_ordinary;
2091       unsigned int shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
2092                                                   &is_ordinary);
2093       lv.set_input_shndx(shndx, is_ordinary);
2094
2095       if (sym.get_st_type() == elfcpp::STT_SECTION)
2096         lv.set_is_section_symbol();
2097       else if (sym.get_st_type() == elfcpp::STT_TLS)
2098         lv.set_is_tls_symbol();
2099       else if (sym.get_st_type() == elfcpp::STT_GNU_IFUNC)
2100         lv.set_is_ifunc_symbol();
2101
2102       // Save the input symbol value for use in do_finalize_local_symbols().
2103       lv.set_input_value(sym.get_st_value());
2104
2105       // Decide whether this symbol should go into the output file.
2106
2107       if ((shndx < shnum && out_sections[shndx] == NULL)
2108           || shndx == this->discarded_eh_frame_shndx_)
2109         {
2110           lv.set_no_output_symtab_entry();
2111           gold_assert(!lv.needs_output_dynsym_entry());
2112           continue;
2113         }
2114
2115       if (sym.get_st_type() == elfcpp::STT_SECTION
2116           || !this->adjust_local_symbol(&lv))
2117         {
2118           lv.set_no_output_symtab_entry();
2119           gold_assert(!lv.needs_output_dynsym_entry());
2120           continue;
2121         }
2122
2123       if (sym.get_st_name() >= strtab_size)
2124         {
2125           this->error(_("local symbol %u section name out of range: %u >= %u"),
2126                       i, sym.get_st_name(),
2127                       static_cast<unsigned int>(strtab_size));
2128           lv.set_no_output_symtab_entry();
2129           continue;
2130         }
2131
2132       const char* name = pnames + sym.get_st_name();
2133
2134       // If needed, add the symbol to the dynamic symbol table string pool.
2135       if (lv.needs_output_dynsym_entry())
2136         {
2137           dynpool->add(name, true, NULL);
2138           ++dyncount;
2139         }
2140
2141       if (strip_all
2142           || (discard_all && lv.may_be_discarded_from_output_symtab()))
2143         {
2144           lv.set_no_output_symtab_entry();
2145           continue;
2146         }
2147
2148       // If --discard-locals option is used, discard all temporary local
2149       // symbols.  These symbols start with system-specific local label
2150       // prefixes, typically .L for ELF system.  We want to be compatible
2151       // with GNU ld so here we essentially use the same check in
2152       // bfd_is_local_label().  The code is different because we already
2153       // know that:
2154       //
2155       //   - the symbol is local and thus cannot have global or weak binding.
2156       //   - the symbol is not a section symbol.
2157       //   - the symbol has a name.
2158       //
2159       // We do not discard a symbol if it needs a dynamic symbol entry.
2160       if (discard_locals
2161           && sym.get_st_type() != elfcpp::STT_FILE
2162           && !lv.needs_output_dynsym_entry()
2163           && lv.may_be_discarded_from_output_symtab()
2164           && parameters->target().is_local_label_name(name))
2165         {
2166           lv.set_no_output_symtab_entry();
2167           continue;
2168         }
2169
2170       // Discard the local symbol if -retain_symbols_file is specified
2171       // and the local symbol is not in that file.
2172       if (!parameters->options().should_retain_symbol(name))
2173         {
2174           lv.set_no_output_symtab_entry();
2175           continue;
2176         }
2177
2178       // Add the symbol to the symbol table string pool.
2179       pool->add(name, true, NULL);
2180       ++count;
2181     }
2182
2183   this->output_local_symbol_count_ = count;
2184   this->output_local_dynsym_count_ = dyncount;
2185 }
2186
2187 // Compute the final value of a local symbol.
2188
2189 template<int size, bool big_endian>
2190 typename Sized_relobj_file<size, big_endian>::Compute_final_local_value_status
2191 Sized_relobj_file<size, big_endian>::compute_final_local_value_internal(
2192     unsigned int r_sym,
2193     const Symbol_value<size>* lv_in,
2194     Symbol_value<size>* lv_out,
2195     bool relocatable,
2196     const Output_sections& out_sections,
2197     const std::vector<Address>& out_offsets,
2198     const Symbol_table* symtab)
2199 {
2200   // We are going to overwrite *LV_OUT, if it has a merged symbol value,
2201   // we may have a memory leak.
2202   gold_assert(lv_out->has_output_value());
2203
2204   bool is_ordinary;
2205   unsigned int shndx = lv_in->input_shndx(&is_ordinary);
2206
2207   // Set the output symbol value.
2208
2209   if (!is_ordinary)
2210     {
2211       if (shndx == elfcpp::SHN_ABS || Symbol::is_common_shndx(shndx))
2212         lv_out->set_output_value(lv_in->input_value());
2213       else
2214         {
2215           this->error(_("unknown section index %u for local symbol %u"),
2216                       shndx, r_sym);
2217           lv_out->set_output_value(0);
2218           return This::CFLV_ERROR;
2219         }
2220     }
2221   else
2222     {
2223       if (shndx >= this->shnum())
2224         {
2225           this->error(_("local symbol %u section index %u out of range"),
2226                       r_sym, shndx);
2227           lv_out->set_output_value(0);
2228           return This::CFLV_ERROR;
2229         }
2230
2231       Output_section* os = out_sections[shndx];
2232       Address secoffset = out_offsets[shndx];
2233       if (symtab->is_section_folded(this, shndx))
2234         {
2235           gold_assert(os == NULL && secoffset == invalid_address);
2236           // Get the os of the section it is folded onto.
2237           Section_id folded = symtab->icf()->get_folded_section(this,
2238                                                                 shndx);
2239           gold_assert(folded.first != NULL);
2240           Sized_relobj_file<size, big_endian>* folded_obj = reinterpret_cast
2241             <Sized_relobj_file<size, big_endian>*>(folded.first);
2242           os = folded_obj->output_section(folded.second);
2243           gold_assert(os != NULL);
2244           secoffset = folded_obj->get_output_section_offset(folded.second);
2245
2246           // This could be a relaxed input section.
2247           if (secoffset == invalid_address)
2248             {
2249               const Output_relaxed_input_section* relaxed_section =
2250                 os->find_relaxed_input_section(folded_obj, folded.second);
2251               gold_assert(relaxed_section != NULL);
2252               secoffset = relaxed_section->address() - os->address();
2253             }
2254         }
2255
2256       if (os == NULL)
2257         {
2258           // This local symbol belongs to a section we are discarding.
2259           // In some cases when applying relocations later, we will
2260           // attempt to match it to the corresponding kept section,
2261           // so we leave the input value unchanged here.
2262           return This::CFLV_DISCARDED;
2263         }
2264       else if (secoffset == invalid_address)
2265         {
2266           uint64_t start;
2267
2268           // This is a SHF_MERGE section or one which otherwise
2269           // requires special handling.
2270           if (shndx == this->discarded_eh_frame_shndx_)
2271             {
2272               // This local symbol belongs to a discarded .eh_frame
2273               // section.  Just treat it like the case in which
2274               // os == NULL above.
2275               gold_assert(this->has_eh_frame_);
2276               return This::CFLV_DISCARDED;
2277             }
2278           else if (!lv_in->is_section_symbol())
2279             {
2280               // This is not a section symbol.  We can determine
2281               // the final value now.
2282               lv_out->set_output_value(
2283                   os->output_address(this, shndx, lv_in->input_value()));
2284             }
2285           else if (!os->find_starting_output_address(this, shndx, &start))
2286             {
2287               // This is a section symbol, but apparently not one in a
2288               // merged section.  First check to see if this is a relaxed
2289               // input section.  If so, use its address.  Otherwise just
2290               // use the start of the output section.  This happens with
2291               // relocatable links when the input object has section
2292               // symbols for arbitrary non-merge sections.
2293               const Output_section_data* posd =
2294                 os->find_relaxed_input_section(this, shndx);
2295               if (posd != NULL)
2296                 {
2297                   Address relocatable_link_adjustment =
2298                     relocatable ? os->address() : 0;
2299                   lv_out->set_output_value(posd->address()
2300                                            - relocatable_link_adjustment);
2301                 }
2302               else
2303                 lv_out->set_output_value(os->address());
2304             }
2305           else
2306             {
2307               // We have to consider the addend to determine the
2308               // value to use in a relocation.  START is the start
2309               // of this input section.  If we are doing a relocatable
2310               // link, use offset from start output section instead of
2311               // address.
2312               Address adjusted_start =
2313                 relocatable ? start - os->address() : start;
2314               Merged_symbol_value<size>* msv =
2315                 new Merged_symbol_value<size>(lv_in->input_value(),
2316                                               adjusted_start);
2317               lv_out->set_merged_symbol_value(msv);
2318             }
2319         }
2320       else if (lv_in->is_tls_symbol())
2321         lv_out->set_output_value(os->tls_offset()
2322                                  + secoffset
2323                                  + lv_in->input_value());
2324       else
2325         lv_out->set_output_value((relocatable ? 0 : os->address())
2326                                  + secoffset
2327                                  + lv_in->input_value());
2328     }
2329   return This::CFLV_OK;
2330 }
2331
2332 // Compute final local symbol value.  R_SYM is the index of a local
2333 // symbol in symbol table.  LV points to a symbol value, which is
2334 // expected to hold the input value and to be over-written by the
2335 // final value.  SYMTAB points to a symbol table.  Some targets may want
2336 // to know would-be-finalized local symbol values in relaxation.
2337 // Hence we provide this method.  Since this method updates *LV, a
2338 // callee should make a copy of the original local symbol value and
2339 // use the copy instead of modifying an object's local symbols before
2340 // everything is finalized.  The caller should also free up any allocated
2341 // memory in the return value in *LV.
2342 template<int size, bool big_endian>
2343 typename Sized_relobj_file<size, big_endian>::Compute_final_local_value_status
2344 Sized_relobj_file<size, big_endian>::compute_final_local_value(
2345     unsigned int r_sym,
2346     const Symbol_value<size>* lv_in,
2347     Symbol_value<size>* lv_out,
2348     const Symbol_table* symtab)
2349 {
2350   // This is just a wrapper of compute_final_local_value_internal.
2351   const bool relocatable = parameters->options().relocatable();
2352   const Output_sections& out_sections(this->output_sections());
2353   const std::vector<Address>& out_offsets(this->section_offsets());
2354   return this->compute_final_local_value_internal(r_sym, lv_in, lv_out,
2355                                                   relocatable, out_sections,
2356                                                   out_offsets, symtab);
2357 }
2358
2359 // Finalize the local symbols.  Here we set the final value in
2360 // THIS->LOCAL_VALUES_ and set their output symbol table indexes.
2361 // This function is always called from a singleton thread.  The actual
2362 // output of the local symbols will occur in a separate task.
2363
2364 template<int size, bool big_endian>
2365 unsigned int
2366 Sized_relobj_file<size, big_endian>::do_finalize_local_symbols(
2367     unsigned int index,
2368     off_t off,
2369     Symbol_table* symtab)
2370 {
2371   gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
2372
2373   const unsigned int loccount = this->local_symbol_count_;
2374   this->local_symbol_offset_ = off;
2375
2376   const bool relocatable = parameters->options().relocatable();
2377   const Output_sections& out_sections(this->output_sections());
2378   const std::vector<Address>& out_offsets(this->section_offsets());
2379
2380   for (unsigned int i = 1; i < loccount; ++i)
2381     {
2382       Symbol_value<size>* lv = &this->local_values_[i];
2383
2384       Compute_final_local_value_status cflv_status =
2385         this->compute_final_local_value_internal(i, lv, lv, relocatable,
2386                                                  out_sections, out_offsets,
2387                                                  symtab);
2388       switch (cflv_status)
2389         {
2390         case CFLV_OK:
2391           if (!lv->is_output_symtab_index_set())
2392             {
2393               lv->set_output_symtab_index(index);
2394               ++index;
2395             }
2396           break;
2397         case CFLV_DISCARDED:
2398         case CFLV_ERROR:
2399           // Do nothing.
2400           break;
2401         default:
2402           gold_unreachable();
2403         }
2404     }
2405   return index;
2406 }
2407
2408 // Set the output dynamic symbol table indexes for the local variables.
2409
2410 template<int size, bool big_endian>
2411 unsigned int
2412 Sized_relobj_file<size, big_endian>::do_set_local_dynsym_indexes(
2413     unsigned int index)
2414 {
2415   const unsigned int loccount = this->local_symbol_count_;
2416   for (unsigned int i = 1; i < loccount; ++i)
2417     {
2418       Symbol_value<size>& lv(this->local_values_[i]);
2419       if (lv.needs_output_dynsym_entry())
2420         {
2421           lv.set_output_dynsym_index(index);
2422           ++index;
2423         }
2424     }
2425   return index;
2426 }
2427
2428 // Set the offset where local dynamic symbol information will be stored.
2429 // Returns the count of local symbols contributed to the symbol table by
2430 // this object.
2431
2432 template<int size, bool big_endian>
2433 unsigned int
2434 Sized_relobj_file<size, big_endian>::do_set_local_dynsym_offset(off_t off)
2435 {
2436   gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
2437   this->local_dynsym_offset_ = off;
2438   return this->output_local_dynsym_count_;
2439 }
2440
2441 // If Symbols_data is not NULL get the section flags from here otherwise
2442 // get it from the file.
2443
2444 template<int size, bool big_endian>
2445 uint64_t
2446 Sized_relobj_file<size, big_endian>::do_section_flags(unsigned int shndx)
2447 {
2448   Symbols_data* sd = this->get_symbols_data();
2449   if (sd != NULL)
2450     {
2451       const unsigned char* pshdrs = sd->section_headers_data
2452                                     + This::shdr_size * shndx;
2453       typename This::Shdr shdr(pshdrs);
2454       return shdr.get_sh_flags();
2455     }
2456   // If sd is NULL, read the section header from the file.
2457   return this->elf_file_.section_flags(shndx);
2458 }
2459
2460 // Get the section's ent size from Symbols_data.  Called by get_section_contents
2461 // in icf.cc
2462
2463 template<int size, bool big_endian>
2464 uint64_t
2465 Sized_relobj_file<size, big_endian>::do_section_entsize(unsigned int shndx)
2466 {
2467   Symbols_data* sd = this->get_symbols_data();
2468   gold_assert(sd != NULL);
2469
2470   const unsigned char* pshdrs = sd->section_headers_data
2471                                 + This::shdr_size * shndx;
2472   typename This::Shdr shdr(pshdrs);
2473   return shdr.get_sh_entsize();
2474 }
2475
2476 // Write out the local symbols.
2477
2478 template<int size, bool big_endian>
2479 void
2480 Sized_relobj_file<size, big_endian>::write_local_symbols(
2481     Output_file* of,
2482     const Stringpool* sympool,
2483     const Stringpool* dynpool,
2484     Output_symtab_xindex* symtab_xindex,
2485     Output_symtab_xindex* dynsym_xindex,
2486     off_t symtab_off)
2487 {
2488   const bool strip_all = parameters->options().strip_all();
2489   if (strip_all)
2490     {
2491       if (this->output_local_dynsym_count_ == 0)
2492         return;
2493       this->output_local_symbol_count_ = 0;
2494     }
2495
2496   gold_assert(this->symtab_shndx_ != -1U);
2497   if (this->symtab_shndx_ == 0)
2498     {
2499       // This object has no symbols.  Weird but legal.
2500       return;
2501     }
2502
2503   // Read the symbol table section header.
2504   const unsigned int symtab_shndx = this->symtab_shndx_;
2505   typename This::Shdr symtabshdr(this,
2506                                  this->elf_file_.section_header(symtab_shndx));
2507   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
2508   const unsigned int loccount = this->local_symbol_count_;
2509   gold_assert(loccount == symtabshdr.get_sh_info());
2510
2511   // Read the local symbols.
2512   const int sym_size = This::sym_size;
2513   off_t locsize = loccount * sym_size;
2514   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
2515                                               locsize, true, false);
2516
2517   // Read the symbol names.
2518   const unsigned int strtab_shndx =
2519     this->adjust_shndx(symtabshdr.get_sh_link());
2520   section_size_type strtab_size;
2521   const unsigned char* pnamesu = this->section_contents(strtab_shndx,
2522                                                         &strtab_size,
2523                                                         false);
2524   const char* pnames = reinterpret_cast<const char*>(pnamesu);
2525
2526   // Get views into the output file for the portions of the symbol table
2527   // and the dynamic symbol table that we will be writing.
2528   off_t output_size = this->output_local_symbol_count_ * sym_size;
2529   unsigned char* oview = NULL;
2530   if (output_size > 0)
2531     oview = of->get_output_view(symtab_off + this->local_symbol_offset_,
2532                                 output_size);
2533
2534   off_t dyn_output_size = this->output_local_dynsym_count_ * sym_size;
2535   unsigned char* dyn_oview = NULL;
2536   if (dyn_output_size > 0)
2537     dyn_oview = of->get_output_view(this->local_dynsym_offset_,
2538                                     dyn_output_size);
2539
2540   const Output_sections out_sections(this->output_sections());
2541
2542   gold_assert(this->local_values_.size() == loccount);
2543
2544   unsigned char* ov = oview;
2545   unsigned char* dyn_ov = dyn_oview;
2546   psyms += sym_size;
2547   for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
2548     {
2549       elfcpp::Sym<size, big_endian> isym(psyms);
2550
2551       Symbol_value<size>& lv(this->local_values_[i]);
2552
2553       bool is_ordinary;
2554       unsigned int st_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
2555                                                      &is_ordinary);
2556       if (is_ordinary)
2557         {
2558           gold_assert(st_shndx < out_sections.size());
2559           if (out_sections[st_shndx] == NULL)
2560             continue;
2561           st_shndx = out_sections[st_shndx]->out_shndx();
2562           if (st_shndx >= elfcpp::SHN_LORESERVE)
2563             {
2564               if (lv.has_output_symtab_entry())
2565                 symtab_xindex->add(lv.output_symtab_index(), st_shndx);
2566               if (lv.has_output_dynsym_entry())
2567                 dynsym_xindex->add(lv.output_dynsym_index(), st_shndx);
2568               st_shndx = elfcpp::SHN_XINDEX;
2569             }
2570         }
2571
2572       // Write the symbol to the output symbol table.
2573       if (lv.has_output_symtab_entry())
2574         {
2575           elfcpp::Sym_write<size, big_endian> osym(ov);
2576
2577           gold_assert(isym.get_st_name() < strtab_size);
2578           const char* name = pnames + isym.get_st_name();
2579           osym.put_st_name(sympool->get_offset(name));
2580           osym.put_st_value(this->local_values_[i].value(this, 0));
2581           osym.put_st_size(isym.get_st_size());
2582           osym.put_st_info(isym.get_st_info());
2583           osym.put_st_other(isym.get_st_other());
2584           osym.put_st_shndx(st_shndx);
2585
2586           ov += sym_size;
2587         }
2588
2589       // Write the symbol to the output dynamic symbol table.
2590       if (lv.has_output_dynsym_entry())
2591         {
2592           gold_assert(dyn_ov < dyn_oview + dyn_output_size);
2593           elfcpp::Sym_write<size, big_endian> osym(dyn_ov);
2594
2595           gold_assert(isym.get_st_name() < strtab_size);
2596           const char* name = pnames + isym.get_st_name();
2597           osym.put_st_name(dynpool->get_offset(name));
2598           osym.put_st_value(this->local_values_[i].value(this, 0));
2599           osym.put_st_size(isym.get_st_size());
2600           osym.put_st_info(isym.get_st_info());
2601           osym.put_st_other(isym.get_st_other());
2602           osym.put_st_shndx(st_shndx);
2603
2604           dyn_ov += sym_size;
2605         }
2606     }
2607
2608
2609   if (output_size > 0)
2610     {
2611       gold_assert(ov - oview == output_size);
2612       of->write_output_view(symtab_off + this->local_symbol_offset_,
2613                             output_size, oview);
2614     }
2615
2616   if (dyn_output_size > 0)
2617     {
2618       gold_assert(dyn_ov - dyn_oview == dyn_output_size);
2619       of->write_output_view(this->local_dynsym_offset_, dyn_output_size,
2620                             dyn_oview);
2621     }
2622 }
2623
2624 // Set *INFO to symbolic information about the offset OFFSET in the
2625 // section SHNDX.  Return true if we found something, false if we
2626 // found nothing.
2627
2628 template<int size, bool big_endian>
2629 bool
2630 Sized_relobj_file<size, big_endian>::get_symbol_location_info(
2631     unsigned int shndx,
2632     off_t offset,
2633     Symbol_location_info* info)
2634 {
2635   if (this->symtab_shndx_ == 0)
2636     return false;
2637
2638   section_size_type symbols_size;
2639   const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
2640                                                         &symbols_size,
2641                                                         false);
2642
2643   unsigned int symbol_names_shndx =
2644     this->adjust_shndx(this->section_link(this->symtab_shndx_));
2645   section_size_type names_size;
2646   const unsigned char* symbol_names_u =
2647     this->section_contents(symbol_names_shndx, &names_size, false);
2648   const char* symbol_names = reinterpret_cast<const char*>(symbol_names_u);
2649
2650   const int sym_size = This::sym_size;
2651   const size_t count = symbols_size / sym_size;
2652
2653   const unsigned char* p = symbols;
2654   for (size_t i = 0; i < count; ++i, p += sym_size)
2655     {
2656       elfcpp::Sym<size, big_endian> sym(p);
2657
2658       if (sym.get_st_type() == elfcpp::STT_FILE)
2659         {
2660           if (sym.get_st_name() >= names_size)
2661             info->source_file = "(invalid)";
2662           else
2663             info->source_file = symbol_names + sym.get_st_name();
2664           continue;
2665         }
2666
2667       bool is_ordinary;
2668       unsigned int st_shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
2669                                                      &is_ordinary);
2670       if (is_ordinary
2671           && st_shndx == shndx
2672           && static_cast<off_t>(sym.get_st_value()) <= offset
2673           && (static_cast<off_t>(sym.get_st_value() + sym.get_st_size())
2674               > offset))
2675         {
2676           if (sym.get_st_name() > names_size)
2677             info->enclosing_symbol_name = "(invalid)";
2678           else
2679             {
2680               info->enclosing_symbol_name = symbol_names + sym.get_st_name();
2681               if (parameters->options().do_demangle())
2682                 {
2683                   char* demangled_name = cplus_demangle(
2684                       info->enclosing_symbol_name.c_str(),
2685                       DMGL_ANSI | DMGL_PARAMS);
2686                   if (demangled_name != NULL)
2687                     {
2688                       info->enclosing_symbol_name.assign(demangled_name);
2689                       free(demangled_name);
2690                     }
2691                 }
2692             }
2693           return true;
2694         }
2695     }
2696
2697   return false;
2698 }
2699
2700 // Look for a kept section corresponding to the given discarded section,
2701 // and return its output address.  This is used only for relocations in
2702 // debugging sections.  If we can't find the kept section, return 0.
2703
2704 template<int size, bool big_endian>
2705 typename Sized_relobj_file<size, big_endian>::Address
2706 Sized_relobj_file<size, big_endian>::map_to_kept_section(
2707     unsigned int shndx,
2708     bool* found) const
2709 {
2710   Relobj* kept_object;
2711   unsigned int kept_shndx;
2712   if (this->get_kept_comdat_section(shndx, &kept_object, &kept_shndx))
2713     {
2714       Sized_relobj_file<size, big_endian>* kept_relobj =
2715         static_cast<Sized_relobj_file<size, big_endian>*>(kept_object);
2716       Output_section* os = kept_relobj->output_section(kept_shndx);
2717       Address offset = kept_relobj->get_output_section_offset(kept_shndx);
2718       if (os != NULL && offset != invalid_address)
2719         {
2720           *found = true;
2721           return os->address() + offset;
2722         }
2723     }
2724   *found = false;
2725   return 0;
2726 }
2727
2728 // Get symbol counts.
2729
2730 template<int size, bool big_endian>
2731 void
2732 Sized_relobj_file<size, big_endian>::do_get_global_symbol_counts(
2733     const Symbol_table*,
2734     size_t* defined,
2735     size_t* used) const
2736 {
2737   *defined = this->defined_count_;
2738   size_t count = 0;
2739   for (typename Symbols::const_iterator p = this->symbols_.begin();
2740        p != this->symbols_.end();
2741        ++p)
2742     if (*p != NULL
2743         && (*p)->source() == Symbol::FROM_OBJECT
2744         && (*p)->object() == this
2745         && (*p)->is_defined())
2746       ++count;
2747   *used = count;
2748 }
2749
2750 // Return a view of the decompressed contents of a section.  Set *PLEN
2751 // to the size.  Set *IS_NEW to true if the contents need to be freed
2752 // by the caller.
2753
2754 template<int size, bool big_endian>
2755 const unsigned char*
2756 Sized_relobj_file<size, big_endian>::do_decompressed_section_contents(
2757     unsigned int shndx,
2758     section_size_type* plen,
2759     bool* is_new)
2760 {
2761   section_size_type buffer_size;
2762   const unsigned char* buffer = this->do_section_contents(shndx, &buffer_size,
2763                                                           false);
2764
2765   if (this->compressed_sections_ == NULL)
2766     {
2767       *plen = buffer_size;
2768       *is_new = false;
2769       return buffer;
2770     }
2771
2772   Compressed_section_map::const_iterator p =
2773       this->compressed_sections_->find(shndx);
2774   if (p == this->compressed_sections_->end())
2775     {
2776       *plen = buffer_size;
2777       *is_new = false;
2778       return buffer;
2779     }
2780
2781   section_size_type uncompressed_size = p->second.size;
2782   if (p->second.contents != NULL)
2783     {
2784       *plen = uncompressed_size;
2785       *is_new = false;
2786       return p->second.contents;
2787     }
2788
2789   unsigned char* uncompressed_data = new unsigned char[uncompressed_size];
2790   if (!decompress_input_section(buffer,
2791                                 buffer_size,
2792                                 uncompressed_data,
2793                                 uncompressed_size))
2794     this->error(_("could not decompress section %s"),
2795                 this->do_section_name(shndx).c_str());
2796
2797   // We could cache the results in p->second.contents and store
2798   // false in *IS_NEW, but build_compressed_section_map() would
2799   // have done so if it had expected it to be profitable.  If
2800   // we reach this point, we expect to need the contents only
2801   // once in this pass.
2802   *plen = uncompressed_size;
2803   *is_new = true;
2804   return uncompressed_data;
2805 }
2806
2807 // Discard any buffers of uncompressed sections.  This is done
2808 // at the end of the Add_symbols task.
2809
2810 template<int size, bool big_endian>
2811 void
2812 Sized_relobj_file<size, big_endian>::do_discard_decompressed_sections()
2813 {
2814   if (this->compressed_sections_ == NULL)
2815     return;
2816
2817   for (Compressed_section_map::iterator p = this->compressed_sections_->begin();
2818        p != this->compressed_sections_->end();
2819        ++p)
2820     {
2821       if (p->second.contents != NULL)
2822         {
2823           delete[] p->second.contents;
2824           p->second.contents = NULL;
2825         }
2826     }
2827 }
2828
2829 // Input_objects methods.
2830
2831 // Add a regular relocatable object to the list.  Return false if this
2832 // object should be ignored.
2833
2834 bool
2835 Input_objects::add_object(Object* obj)
2836 {
2837   // Print the filename if the -t/--trace option is selected.
2838   if (parameters->options().trace())
2839     gold_info("%s", obj->name().c_str());
2840
2841   if (!obj->is_dynamic())
2842     this->relobj_list_.push_back(static_cast<Relobj*>(obj));
2843   else
2844     {
2845       // See if this is a duplicate SONAME.
2846       Dynobj* dynobj = static_cast<Dynobj*>(obj);
2847       const char* soname = dynobj->soname();
2848
2849       std::pair<Unordered_set<std::string>::iterator, bool> ins =
2850         this->sonames_.insert(soname);
2851       if (!ins.second)
2852         {
2853           // We have already seen a dynamic object with this soname.
2854           return false;
2855         }
2856
2857       this->dynobj_list_.push_back(dynobj);
2858     }
2859
2860   // Add this object to the cross-referencer if requested.
2861   if (parameters->options().user_set_print_symbol_counts()
2862       || parameters->options().cref())
2863     {
2864       if (this->cref_ == NULL)
2865         this->cref_ = new Cref();
2866       this->cref_->add_object(obj);
2867     }
2868
2869   return true;
2870 }
2871
2872 // For each dynamic object, record whether we've seen all of its
2873 // explicit dependencies.
2874
2875 void
2876 Input_objects::check_dynamic_dependencies() const
2877 {
2878   bool issued_copy_dt_needed_error = false;
2879   for (Dynobj_list::const_iterator p = this->dynobj_list_.begin();
2880        p != this->dynobj_list_.end();
2881        ++p)
2882     {
2883       const Dynobj::Needed& needed((*p)->needed());
2884       bool found_all = true;
2885       Dynobj::Needed::const_iterator pneeded;
2886       for (pneeded = needed.begin(); pneeded != needed.end(); ++pneeded)
2887         {
2888           if (this->sonames_.find(*pneeded) == this->sonames_.end())
2889             {
2890               found_all = false;
2891               break;
2892             }
2893         }
2894       (*p)->set_has_unknown_needed_entries(!found_all);
2895
2896       // --copy-dt-needed-entries aka --add-needed is a GNU ld option
2897       // that gold does not support.  However, they cause no trouble
2898       // unless there is a DT_NEEDED entry that we don't know about;
2899       // warn only in that case.
2900       if (!found_all
2901           && !issued_copy_dt_needed_error
2902           && (parameters->options().copy_dt_needed_entries()
2903               || parameters->options().add_needed()))
2904         {
2905           const char* optname;
2906           if (parameters->options().copy_dt_needed_entries())
2907             optname = "--copy-dt-needed-entries";
2908           else
2909             optname = "--add-needed";
2910           gold_error(_("%s is not supported but is required for %s in %s"),
2911                      optname, (*pneeded).c_str(), (*p)->name().c_str());
2912           issued_copy_dt_needed_error = true;
2913         }
2914     }
2915 }
2916
2917 // Start processing an archive.
2918
2919 void
2920 Input_objects::archive_start(Archive* archive)
2921 {
2922   if (parameters->options().user_set_print_symbol_counts()
2923       || parameters->options().cref())
2924     {
2925       if (this->cref_ == NULL)
2926         this->cref_ = new Cref();
2927       this->cref_->add_archive_start(archive);
2928     }
2929 }
2930
2931 // Stop processing an archive.
2932
2933 void
2934 Input_objects::archive_stop(Archive* archive)
2935 {
2936   if (parameters->options().user_set_print_symbol_counts()
2937       || parameters->options().cref())
2938     this->cref_->add_archive_stop(archive);
2939 }
2940
2941 // Print symbol counts
2942
2943 void
2944 Input_objects::print_symbol_counts(const Symbol_table* symtab) const
2945 {
2946   if (parameters->options().user_set_print_symbol_counts()
2947       && this->cref_ != NULL)
2948     this->cref_->print_symbol_counts(symtab);
2949 }
2950
2951 // Print a cross reference table.
2952
2953 void
2954 Input_objects::print_cref(const Symbol_table* symtab, FILE* f) const
2955 {
2956   if (parameters->options().cref() && this->cref_ != NULL)
2957     this->cref_->print_cref(symtab, f);
2958 }
2959
2960 // Relocate_info methods.
2961
2962 // Return a string describing the location of a relocation when file
2963 // and lineno information is not available.  This is only used in
2964 // error messages.
2965
2966 template<int size, bool big_endian>
2967 std::string
2968 Relocate_info<size, big_endian>::location(size_t, off_t offset) const
2969 {
2970   Sized_dwarf_line_info<size, big_endian> line_info(this->object);
2971   std::string ret = line_info.addr2line(this->data_shndx, offset, NULL);
2972   if (!ret.empty())
2973     return ret;
2974
2975   ret = this->object->name();
2976
2977   Symbol_location_info info;
2978   if (this->object->get_symbol_location_info(this->data_shndx, offset, &info))
2979     {
2980       if (!info.source_file.empty())
2981         {
2982           ret += ":";
2983           ret += info.source_file;
2984         }
2985       size_t len = info.enclosing_symbol_name.length() + 100;
2986       char* buf = new char[len];
2987       snprintf(buf, len, _(":function %s"),
2988                info.enclosing_symbol_name.c_str());
2989       ret += buf;
2990       delete[] buf;
2991       return ret;
2992     }
2993
2994   ret += "(";
2995   ret += this->object->section_name(this->data_shndx);
2996   char buf[100];
2997   snprintf(buf, sizeof buf, "+0x%lx)", static_cast<long>(offset));
2998   ret += buf;
2999   return ret;
3000 }
3001
3002 } // End namespace gold.
3003
3004 namespace
3005 {
3006
3007 using namespace gold;
3008
3009 // Read an ELF file with the header and return the appropriate
3010 // instance of Object.
3011
3012 template<int size, bool big_endian>
3013 Object*
3014 make_elf_sized_object(const std::string& name, Input_file* input_file,
3015                       off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr,
3016                       bool* punconfigured)
3017 {
3018   Target* target = select_target(input_file, offset,
3019                                  ehdr.get_e_machine(), size, big_endian,
3020                                  ehdr.get_e_ident()[elfcpp::EI_OSABI],
3021                                  ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
3022   if (target == NULL)
3023     gold_fatal(_("%s: unsupported ELF machine number %d"),
3024                name.c_str(), ehdr.get_e_machine());
3025
3026   if (!parameters->target_valid())
3027     set_parameters_target(target);
3028   else if (target != &parameters->target())
3029     {
3030       if (punconfigured != NULL)
3031         *punconfigured = true;
3032       else
3033         gold_error(_("%s: incompatible target"), name.c_str());
3034       return NULL;
3035     }
3036
3037   return target->make_elf_object<size, big_endian>(name, input_file, offset,
3038                                                    ehdr);
3039 }
3040
3041 } // End anonymous namespace.
3042
3043 namespace gold
3044 {
3045
3046 // Return whether INPUT_FILE is an ELF object.
3047
3048 bool
3049 is_elf_object(Input_file* input_file, off_t offset,
3050               const unsigned char** start, int* read_size)
3051 {
3052   off_t filesize = input_file->file().filesize();
3053   int want = elfcpp::Elf_recognizer::max_header_size;
3054   if (filesize - offset < want)
3055     want = filesize - offset;
3056
3057   const unsigned char* p = input_file->file().get_view(offset, 0, want,
3058                                                        true, false);
3059   *start = p;
3060   *read_size = want;
3061
3062   return elfcpp::Elf_recognizer::is_elf_file(p, want);
3063 }
3064
3065 // Read an ELF file and return the appropriate instance of Object.
3066
3067 Object*
3068 make_elf_object(const std::string& name, Input_file* input_file, off_t offset,
3069                 const unsigned char* p, section_offset_type bytes,
3070                 bool* punconfigured)
3071 {
3072   if (punconfigured != NULL)
3073     *punconfigured = false;
3074
3075   std::string error;
3076   bool big_endian = false;
3077   int size = 0;
3078   if (!elfcpp::Elf_recognizer::is_valid_header(p, bytes, &size,
3079                                                &big_endian, &error))
3080     {
3081       gold_error(_("%s: %s"), name.c_str(), error.c_str());
3082       return NULL;
3083     }
3084
3085   if (size == 32)
3086     {
3087       if (big_endian)
3088         {
3089 #ifdef HAVE_TARGET_32_BIG
3090           elfcpp::Ehdr<32, true> ehdr(p);
3091           return make_elf_sized_object<32, true>(name, input_file,
3092                                                  offset, ehdr, punconfigured);
3093 #else
3094           if (punconfigured != NULL)
3095             *punconfigured = true;
3096           else
3097             gold_error(_("%s: not configured to support "
3098                          "32-bit big-endian object"),
3099                        name.c_str());
3100           return NULL;
3101 #endif
3102         }
3103       else
3104         {
3105 #ifdef HAVE_TARGET_32_LITTLE
3106           elfcpp::Ehdr<32, false> ehdr(p);
3107           return make_elf_sized_object<32, false>(name, input_file,
3108                                                   offset, ehdr, punconfigured);
3109 #else
3110           if (punconfigured != NULL)
3111             *punconfigured = true;
3112           else
3113             gold_error(_("%s: not configured to support "
3114                          "32-bit little-endian object"),
3115                        name.c_str());
3116           return NULL;
3117 #endif
3118         }
3119     }
3120   else if (size == 64)
3121     {
3122       if (big_endian)
3123         {
3124 #ifdef HAVE_TARGET_64_BIG
3125           elfcpp::Ehdr<64, true> ehdr(p);
3126           return make_elf_sized_object<64, true>(name, input_file,
3127                                                  offset, ehdr, punconfigured);
3128 #else
3129           if (punconfigured != NULL)
3130             *punconfigured = true;
3131           else
3132             gold_error(_("%s: not configured to support "
3133                          "64-bit big-endian object"),
3134                        name.c_str());
3135           return NULL;
3136 #endif
3137         }
3138       else
3139         {
3140 #ifdef HAVE_TARGET_64_LITTLE
3141           elfcpp::Ehdr<64, false> ehdr(p);
3142           return make_elf_sized_object<64, false>(name, input_file,
3143                                                   offset, ehdr, punconfigured);
3144 #else
3145           if (punconfigured != NULL)
3146             *punconfigured = true;
3147           else
3148             gold_error(_("%s: not configured to support "
3149                          "64-bit little-endian object"),
3150                        name.c_str());
3151           return NULL;
3152 #endif
3153         }
3154     }
3155   else
3156     gold_unreachable();
3157 }
3158
3159 // Instantiate the templates we need.
3160
3161 #ifdef HAVE_TARGET_32_LITTLE
3162 template
3163 void
3164 Object::read_section_data<32, false>(elfcpp::Elf_file<32, false, Object>*,
3165                                      Read_symbols_data*);
3166 #endif
3167
3168 #ifdef HAVE_TARGET_32_BIG
3169 template
3170 void
3171 Object::read_section_data<32, true>(elfcpp::Elf_file<32, true, Object>*,
3172                                     Read_symbols_data*);
3173 #endif
3174
3175 #ifdef HAVE_TARGET_64_LITTLE
3176 template
3177 void
3178 Object::read_section_data<64, false>(elfcpp::Elf_file<64, false, Object>*,
3179                                      Read_symbols_data*);
3180 #endif
3181
3182 #ifdef HAVE_TARGET_64_BIG
3183 template
3184 void
3185 Object::read_section_data<64, true>(elfcpp::Elf_file<64, true, Object>*,
3186                                     Read_symbols_data*);
3187 #endif
3188
3189 #ifdef HAVE_TARGET_32_LITTLE
3190 template
3191 class Sized_relobj_file<32, false>;
3192 #endif
3193
3194 #ifdef HAVE_TARGET_32_BIG
3195 template
3196 class Sized_relobj_file<32, true>;
3197 #endif
3198
3199 #ifdef HAVE_TARGET_64_LITTLE
3200 template
3201 class Sized_relobj_file<64, false>;
3202 #endif
3203
3204 #ifdef HAVE_TARGET_64_BIG
3205 template
3206 class Sized_relobj_file<64, true>;
3207 #endif
3208
3209 #ifdef HAVE_TARGET_32_LITTLE
3210 template
3211 struct Relocate_info<32, false>;
3212 #endif
3213
3214 #ifdef HAVE_TARGET_32_BIG
3215 template
3216 struct Relocate_info<32, true>;
3217 #endif
3218
3219 #ifdef HAVE_TARGET_64_LITTLE
3220 template
3221 struct Relocate_info<64, false>;
3222 #endif
3223
3224 #ifdef HAVE_TARGET_64_BIG
3225 template
3226 struct Relocate_info<64, true>;
3227 #endif
3228
3229 #ifdef HAVE_TARGET_32_LITTLE
3230 template
3231 void
3232 Xindex::initialize_symtab_xindex<32, false>(Object*, unsigned int);
3233
3234 template
3235 void
3236 Xindex::read_symtab_xindex<32, false>(Object*, unsigned int,
3237                                       const unsigned char*);
3238 #endif
3239
3240 #ifdef HAVE_TARGET_32_BIG
3241 template
3242 void
3243 Xindex::initialize_symtab_xindex<32, true>(Object*, unsigned int);
3244
3245 template
3246 void
3247 Xindex::read_symtab_xindex<32, true>(Object*, unsigned int,
3248                                      const unsigned char*);
3249 #endif
3250
3251 #ifdef HAVE_TARGET_64_LITTLE
3252 template
3253 void
3254 Xindex::initialize_symtab_xindex<64, false>(Object*, unsigned int);
3255
3256 template
3257 void
3258 Xindex::read_symtab_xindex<64, false>(Object*, unsigned int,
3259                                       const unsigned char*);
3260 #endif
3261
3262 #ifdef HAVE_TARGET_64_BIG
3263 template
3264 void
3265 Xindex::initialize_symtab_xindex<64, true>(Object*, unsigned int);
3266
3267 template
3268 void
3269 Xindex::read_symtab_xindex<64, true>(Object*, unsigned int,
3270                                      const unsigned char*);
3271 #endif
3272
3273 } // End namespace gold.