80897743aef42e880baa795bb31f60d92345868c
[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 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5
6 // This file is part of gold.
7
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 // GNU General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22
23 #include "gold.h"
24
25 #include <cerrno>
26 #include <cstring>
27 #include <cstdarg>
28 #include "demangle.h"
29 #include "libiberty.h"
30
31 #include "gc.h"
32 #include "target-select.h"
33 #include "dwarf_reader.h"
34 #include "layout.h"
35 #include "output.h"
36 #include "symtab.h"
37 #include "cref.h"
38 #include "reloc.h"
39 #include "object.h"
40 #include "dynobj.h"
41 #include "plugin.h"
42
43 namespace gold
44 {
45
46 // Class Xindex.
47
48 // Initialize the symtab_xindex_ array.  Find the SHT_SYMTAB_SHNDX
49 // section and read it in.  SYMTAB_SHNDX is the index of the symbol
50 // table we care about.
51
52 template<int size, bool big_endian>
53 void
54 Xindex::initialize_symtab_xindex(Object* object, unsigned int symtab_shndx)
55 {
56   if (!this->symtab_xindex_.empty())
57     return;
58
59   gold_assert(symtab_shndx != 0);
60
61   // Look through the sections in reverse order, on the theory that it
62   // is more likely to be near the end than the beginning.
63   unsigned int i = object->shnum();
64   while (i > 0)
65     {
66       --i;
67       if (object->section_type(i) == elfcpp::SHT_SYMTAB_SHNDX
68           && this->adjust_shndx(object->section_link(i)) == symtab_shndx)
69         {
70           this->read_symtab_xindex<size, big_endian>(object, i, NULL);
71           return;
72         }
73     }
74
75   object->error(_("missing SHT_SYMTAB_SHNDX section"));
76 }
77
78 // Read in the symtab_xindex_ array, given the section index of the
79 // SHT_SYMTAB_SHNDX section.  If PSHDRS is not NULL, it points at the
80 // section headers.
81
82 template<int size, bool big_endian>
83 void
84 Xindex::read_symtab_xindex(Object* object, unsigned int xindex_shndx,
85                            const unsigned char* pshdrs)
86 {
87   section_size_type bytecount;
88   const unsigned char* contents;
89   if (pshdrs == NULL)
90     contents = object->section_contents(xindex_shndx, &bytecount, false);
91   else
92     {
93       const unsigned char* p = (pshdrs
94                                 + (xindex_shndx
95                                    * elfcpp::Elf_sizes<size>::shdr_size));
96       typename elfcpp::Shdr<size, big_endian> shdr(p);
97       bytecount = convert_to_section_size_type(shdr.get_sh_size());
98       contents = object->get_view(shdr.get_sh_offset(), bytecount, true, false);
99     }
100
101   gold_assert(this->symtab_xindex_.empty());
102   this->symtab_xindex_.reserve(bytecount / 4);
103   for (section_size_type i = 0; i < bytecount; i += 4)
104     {
105       unsigned int shndx = elfcpp::Swap<32, big_endian>::readval(contents + i);
106       // We preadjust the section indexes we save.
107       this->symtab_xindex_.push_back(this->adjust_shndx(shndx));
108     }
109 }
110
111 // Symbol symndx has a section of SHN_XINDEX; return the real section
112 // index.
113
114 unsigned int
115 Xindex::sym_xindex_to_shndx(Object* object, unsigned int symndx)
116 {
117   if (symndx >= this->symtab_xindex_.size())
118     {
119       object->error(_("symbol %u out of range for SHT_SYMTAB_SHNDX section"),
120                     symndx);
121       return elfcpp::SHN_UNDEF;
122     }
123   unsigned int shndx = this->symtab_xindex_[symndx];
124   if (shndx < elfcpp::SHN_LORESERVE || shndx >= object->shnum())
125     {
126       object->error(_("extended index for symbol %u out of range: %u"),
127                     symndx, shndx);
128       return elfcpp::SHN_UNDEF;
129     }
130   return shndx;
131 }
132
133 // Class Object.
134
135 // Report an error for this object file.  This is used by the
136 // elfcpp::Elf_file interface, and also called by the Object code
137 // itself.
138
139 void
140 Object::error(const char* format, ...) const
141 {
142   va_list args;
143   va_start(args, format);
144   char* buf = NULL;
145   if (vasprintf(&buf, format, args) < 0)
146     gold_nomem();
147   va_end(args);
148   gold_error(_("%s: %s"), this->name().c_str(), buf);
149   free(buf);
150 }
151
152 // Return a view of the contents of a section.
153
154 const unsigned char*
155 Object::section_contents(unsigned int shndx, section_size_type* plen,
156                          bool cache)
157 {
158   Location loc(this->do_section_contents(shndx));
159   *plen = convert_to_section_size_type(loc.data_size);
160   if (*plen == 0)
161     {
162       static const unsigned char empty[1] = { '\0' };
163       return empty;
164     }
165   return this->get_view(loc.file_offset, *plen, true, cache);
166 }
167
168 // Read the section data into SD.  This is code common to Sized_relobj
169 // and Sized_dynobj, so we put it into Object.
170
171 template<int size, bool big_endian>
172 void
173 Object::read_section_data(elfcpp::Elf_file<size, big_endian, Object>* elf_file,
174                           Read_symbols_data* sd)
175 {
176   const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
177
178   // Read the section headers.
179   const off_t shoff = elf_file->shoff();
180   const unsigned int shnum = this->shnum();
181   sd->section_headers = this->get_lasting_view(shoff, shnum * shdr_size,
182                                                true, true);
183
184   // Read the section names.
185   const unsigned char* pshdrs = sd->section_headers->data();
186   const unsigned char* pshdrnames = pshdrs + elf_file->shstrndx() * shdr_size;
187   typename elfcpp::Shdr<size, big_endian> shdrnames(pshdrnames);
188
189   if (shdrnames.get_sh_type() != elfcpp::SHT_STRTAB)
190     this->error(_("section name section has wrong type: %u"),
191                 static_cast<unsigned int>(shdrnames.get_sh_type()));
192
193   sd->section_names_size =
194     convert_to_section_size_type(shdrnames.get_sh_size());
195   sd->section_names = this->get_lasting_view(shdrnames.get_sh_offset(),
196                                              sd->section_names_size, false,
197                                              false);
198 }
199
200 // If NAME is the name of a special .gnu.warning section, arrange for
201 // the warning to be issued.  SHNDX is the section index.  Return
202 // whether it is a warning section.
203
204 bool
205 Object::handle_gnu_warning_section(const char* name, unsigned int shndx,
206                                    Symbol_table* symtab)
207 {
208   const char warn_prefix[] = ".gnu.warning.";
209   const int warn_prefix_len = sizeof warn_prefix - 1;
210   if (strncmp(name, warn_prefix, warn_prefix_len) == 0)
211     {
212       // Read the section contents to get the warning text.  It would
213       // be nicer if we only did this if we have to actually issue a
214       // warning.  Unfortunately, warnings are issued as we relocate
215       // sections.  That means that we can not lock the object then,
216       // as we might try to issue the same warning multiple times
217       // simultaneously.
218       section_size_type len;
219       const unsigned char* contents = this->section_contents(shndx, &len,
220                                                              false);
221       if (len == 0)
222         {
223           const char* warning = name + warn_prefix_len;
224           contents = reinterpret_cast<const unsigned char*>(warning);
225           len = strlen(warning);
226         }
227       std::string warning(reinterpret_cast<const char*>(contents), len);
228       symtab->add_warning(name + warn_prefix_len, this, warning);
229       return true;
230     }
231   return false;
232 }
233
234 // If NAME is the name of the special section which indicates that
235 // this object was compiled with -fstack-split, mark it accordingly.
236
237 bool
238 Object::handle_split_stack_section(const char* name)
239 {
240   if (strcmp(name, ".note.GNU-split-stack") == 0)
241     {
242       this->uses_split_stack_ = true;
243       return true;
244     }
245   if (strcmp(name, ".note.GNU-no-split-stack") == 0)
246     {
247       this->has_no_split_stack_ = true;
248       return true;
249     }
250   return false;
251 }
252
253 // Class Relobj
254
255 // To copy the symbols data read from the file to a local data structure.
256 // This function is called from do_layout only while doing garbage 
257 // collection.
258
259 void
260 Relobj::copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd, 
261                           unsigned int section_header_size)
262 {
263   gc_sd->section_headers_data = 
264          new unsigned char[(section_header_size)];
265   memcpy(gc_sd->section_headers_data, sd->section_headers->data(),
266          section_header_size);
267   gc_sd->section_names_data = 
268          new unsigned char[sd->section_names_size];
269   memcpy(gc_sd->section_names_data, sd->section_names->data(),
270          sd->section_names_size);
271   gc_sd->section_names_size = sd->section_names_size;
272   if (sd->symbols != NULL)
273     {
274       gc_sd->symbols_data = 
275              new unsigned char[sd->symbols_size];
276       memcpy(gc_sd->symbols_data, sd->symbols->data(),
277             sd->symbols_size);
278     }
279   else
280     {
281       gc_sd->symbols_data = NULL;
282     }
283   gc_sd->symbols_size = sd->symbols_size;
284   gc_sd->external_symbols_offset = sd->external_symbols_offset;
285   if (sd->symbol_names != NULL)
286     {
287       gc_sd->symbol_names_data =
288              new unsigned char[sd->symbol_names_size];
289       memcpy(gc_sd->symbol_names_data, sd->symbol_names->data(),
290             sd->symbol_names_size);
291     }
292   else
293     {
294       gc_sd->symbol_names_data = NULL;
295     }
296   gc_sd->symbol_names_size = sd->symbol_names_size;
297 }
298
299 // This function determines if a particular section name must be included
300 // in the link.  This is used during garbage collection to determine the
301 // roots of the worklist.
302
303 bool
304 Relobj::is_section_name_included(const char* name)
305 {
306   if (is_prefix_of(".ctors", name) 
307       || is_prefix_of(".dtors", name) 
308       || is_prefix_of(".note", name) 
309       || is_prefix_of(".init", name) 
310       || is_prefix_of(".fini", name) 
311       || is_prefix_of(".gcc_except_table", name) 
312       || is_prefix_of(".jcr", name) 
313       || is_prefix_of(".preinit_array", name) 
314       || (is_prefix_of(".text", name) 
315           && strstr(name, "personality")) 
316       || (is_prefix_of(".data", name) 
317           &&  strstr(name, "personality")) 
318       || (is_prefix_of(".gnu.linkonce.d", name) && 
319             strstr(name, "personality")))
320     {
321       return true; 
322     }
323   return false;
324 }
325
326 // Class Sized_relobj.
327
328 template<int size, bool big_endian>
329 Sized_relobj<size, big_endian>::Sized_relobj(
330     const std::string& name,
331     Input_file* input_file,
332     off_t offset,
333     const elfcpp::Ehdr<size, big_endian>& ehdr)
334   : Relobj(name, input_file, offset),
335     elf_file_(this, ehdr),
336     symtab_shndx_(-1U),
337     local_symbol_count_(0),
338     output_local_symbol_count_(0),
339     output_local_dynsym_count_(0),
340     symbols_(),
341     defined_count_(0),
342     local_symbol_offset_(0),
343     local_dynsym_offset_(0),
344     local_values_(),
345     local_got_offsets_(),
346     kept_comdat_sections_(),
347     has_eh_frame_(false),
348     discarded_eh_frame_shndx_(-1U)
349 {
350 }
351
352 template<int size, bool big_endian>
353 Sized_relobj<size, big_endian>::~Sized_relobj()
354 {
355 }
356
357 // Set up an object file based on the file header.  This sets up the
358 // section information.
359
360 template<int size, bool big_endian>
361 void
362 Sized_relobj<size, big_endian>::do_setup()
363 {
364   const unsigned int shnum = this->elf_file_.shnum();
365   this->set_shnum(shnum);
366 }
367
368 // Find the SHT_SYMTAB section, given the section headers.  The ELF
369 // standard says that maybe in the future there can be more than one
370 // SHT_SYMTAB section.  Until somebody figures out how that could
371 // work, we assume there is only one.
372
373 template<int size, bool big_endian>
374 void
375 Sized_relobj<size, big_endian>::find_symtab(const unsigned char* pshdrs)
376 {
377   const unsigned int shnum = this->shnum();
378   this->symtab_shndx_ = 0;
379   if (shnum > 0)
380     {
381       // Look through the sections in reverse order, since gas tends
382       // to put the symbol table at the end.
383       const unsigned char* p = pshdrs + shnum * This::shdr_size;
384       unsigned int i = shnum;
385       unsigned int xindex_shndx = 0;
386       unsigned int xindex_link = 0;
387       while (i > 0)
388         {
389           --i;
390           p -= This::shdr_size;
391           typename This::Shdr shdr(p);
392           if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB)
393             {
394               this->symtab_shndx_ = i;
395               if (xindex_shndx > 0 && xindex_link == i)
396                 {
397                   Xindex* xindex =
398                     new Xindex(this->elf_file_.large_shndx_offset());
399                   xindex->read_symtab_xindex<size, big_endian>(this,
400                                                                xindex_shndx,
401                                                                pshdrs);
402                   this->set_xindex(xindex);
403                 }
404               break;
405             }
406
407           // Try to pick up the SHT_SYMTAB_SHNDX section, if there is
408           // one.  This will work if it follows the SHT_SYMTAB
409           // section.
410           if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX)
411             {
412               xindex_shndx = i;
413               xindex_link = this->adjust_shndx(shdr.get_sh_link());
414             }
415         }
416     }
417 }
418
419 // Return the Xindex structure to use for object with lots of
420 // sections.
421
422 template<int size, bool big_endian>
423 Xindex*
424 Sized_relobj<size, big_endian>::do_initialize_xindex()
425 {
426   gold_assert(this->symtab_shndx_ != -1U);
427   Xindex* xindex = new Xindex(this->elf_file_.large_shndx_offset());
428   xindex->initialize_symtab_xindex<size, big_endian>(this, this->symtab_shndx_);
429   return xindex;
430 }
431
432 // Return whether SHDR has the right type and flags to be a GNU
433 // .eh_frame section.
434
435 template<int size, bool big_endian>
436 bool
437 Sized_relobj<size, big_endian>::check_eh_frame_flags(
438     const elfcpp::Shdr<size, big_endian>* shdr) const
439 {
440   return (shdr->get_sh_type() == elfcpp::SHT_PROGBITS
441           && (shdr->get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
442 }
443
444 // Return whether there is a GNU .eh_frame section, given the section
445 // headers and the section names.
446
447 template<int size, bool big_endian>
448 bool
449 Sized_relobj<size, big_endian>::find_eh_frame(
450     const unsigned char* pshdrs,
451     const char* names,
452     section_size_type names_size) const
453 {
454   const unsigned int shnum = this->shnum();
455   const unsigned char* p = pshdrs + This::shdr_size;
456   for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
457     {
458       typename This::Shdr shdr(p);
459       if (this->check_eh_frame_flags(&shdr))
460         {
461           if (shdr.get_sh_name() >= names_size)
462             {
463               this->error(_("bad section name offset for section %u: %lu"),
464                           i, static_cast<unsigned long>(shdr.get_sh_name()));
465               continue;
466             }
467
468           const char* name = names + shdr.get_sh_name();
469           if (strcmp(name, ".eh_frame") == 0)
470             return true;
471         }
472     }
473   return false;
474 }
475
476 // Read the sections and symbols from an object file.
477
478 template<int size, bool big_endian>
479 void
480 Sized_relobj<size, big_endian>::do_read_symbols(Read_symbols_data* sd)
481 {
482   this->read_section_data(&this->elf_file_, sd);
483
484   const unsigned char* const pshdrs = sd->section_headers->data();
485
486   this->find_symtab(pshdrs);
487
488   const unsigned char* namesu = sd->section_names->data();
489   const char* names = reinterpret_cast<const char*>(namesu);
490   if (memmem(names, sd->section_names_size, ".eh_frame", 10) != NULL)
491     {
492       if (this->find_eh_frame(pshdrs, names, sd->section_names_size))
493         this->has_eh_frame_ = true;
494     }
495
496   sd->symbols = NULL;
497   sd->symbols_size = 0;
498   sd->external_symbols_offset = 0;
499   sd->symbol_names = NULL;
500   sd->symbol_names_size = 0;
501
502   if (this->symtab_shndx_ == 0)
503     {
504       // No symbol table.  Weird but legal.
505       return;
506     }
507
508   // Get the symbol table section header.
509   typename This::Shdr symtabshdr(pshdrs
510                                  + this->symtab_shndx_ * This::shdr_size);
511   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
512
513   // If this object has a .eh_frame section, we need all the symbols.
514   // Otherwise we only need the external symbols.  While it would be
515   // simpler to just always read all the symbols, I've seen object
516   // files with well over 2000 local symbols, which for a 64-bit
517   // object file format is over 5 pages that we don't need to read
518   // now.
519
520   const int sym_size = This::sym_size;
521   const unsigned int loccount = symtabshdr.get_sh_info();
522   this->local_symbol_count_ = loccount;
523   this->local_values_.resize(loccount);
524   section_offset_type locsize = loccount * sym_size;
525   off_t dataoff = symtabshdr.get_sh_offset();
526   section_size_type datasize =
527     convert_to_section_size_type(symtabshdr.get_sh_size());
528   off_t extoff = dataoff + locsize;
529   section_size_type extsize = datasize - locsize;
530
531   off_t readoff = this->has_eh_frame_ ? dataoff : extoff;
532   section_size_type readsize = this->has_eh_frame_ ? datasize : extsize;
533
534   if (readsize == 0)
535     {
536       // No external symbols.  Also weird but also legal.
537       return;
538     }
539
540   File_view* fvsymtab = this->get_lasting_view(readoff, readsize, true, false);
541
542   // Read the section header for the symbol names.
543   unsigned int strtab_shndx = this->adjust_shndx(symtabshdr.get_sh_link());
544   if (strtab_shndx >= this->shnum())
545     {
546       this->error(_("invalid symbol table name index: %u"), strtab_shndx);
547       return;
548     }
549   typename This::Shdr strtabshdr(pshdrs + strtab_shndx * This::shdr_size);
550   if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB)
551     {
552       this->error(_("symbol table name section has wrong type: %u"),
553                   static_cast<unsigned int>(strtabshdr.get_sh_type()));
554       return;
555     }
556
557   // Read the symbol names.
558   File_view* fvstrtab = this->get_lasting_view(strtabshdr.get_sh_offset(),
559                                                strtabshdr.get_sh_size(),
560                                                false, true);
561
562   sd->symbols = fvsymtab;
563   sd->symbols_size = readsize;
564   sd->external_symbols_offset = this->has_eh_frame_ ? locsize : 0;
565   sd->symbol_names = fvstrtab;
566   sd->symbol_names_size =
567     convert_to_section_size_type(strtabshdr.get_sh_size());
568 }
569
570 // Return the section index of symbol SYM.  Set *VALUE to its value in
571 // the object file.  Set *IS_ORDINARY if this is an ordinary section
572 // index.  not a special cod between SHN_LORESERVE and SHN_HIRESERVE.
573 // Note that for a symbol which is not defined in this object file,
574 // this will set *VALUE to 0 and return SHN_UNDEF; it will not return
575 // the final value of the symbol in the link.
576
577 template<int size, bool big_endian>
578 unsigned int
579 Sized_relobj<size, big_endian>::symbol_section_and_value(unsigned int sym,
580                                                          Address* value,
581                                                          bool* is_ordinary)
582 {
583   section_size_type symbols_size;
584   const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
585                                                         &symbols_size,
586                                                         false);
587
588   const size_t count = symbols_size / This::sym_size;
589   gold_assert(sym < count);
590
591   elfcpp::Sym<size, big_endian> elfsym(symbols + sym * This::sym_size);
592   *value = elfsym.get_st_value();
593
594   return this->adjust_sym_shndx(sym, elfsym.get_st_shndx(), is_ordinary);
595 }
596
597 // Return whether to include a section group in the link.  LAYOUT is
598 // used to keep track of which section groups we have already seen.
599 // INDEX is the index of the section group and SHDR is the section
600 // header.  If we do not want to include this group, we set bits in
601 // OMIT for each section which should be discarded.
602
603 template<int size, bool big_endian>
604 bool
605 Sized_relobj<size, big_endian>::include_section_group(
606     Symbol_table* symtab,
607     Layout* layout,
608     unsigned int index,
609     const char* name,
610     const unsigned char* shdrs,
611     const char* section_names,
612     section_size_type section_names_size,
613     std::vector<bool>* omit)
614 {
615   // Read the section contents.
616   typename This::Shdr shdr(shdrs + index * This::shdr_size);
617   const unsigned char* pcon = this->get_view(shdr.get_sh_offset(),
618                                              shdr.get_sh_size(), true, false);
619   const elfcpp::Elf_Word* pword =
620     reinterpret_cast<const elfcpp::Elf_Word*>(pcon);
621
622   // The first word contains flags.  We only care about COMDAT section
623   // groups.  Other section groups are always included in the link
624   // just like ordinary sections.
625   elfcpp::Elf_Word flags = elfcpp::Swap<32, big_endian>::readval(pword);
626
627   // Look up the group signature, which is the name of a symbol.  This
628   // is a lot of effort to go to to read a string.  Why didn't they
629   // just have the group signature point into the string table, rather
630   // than indirect through a symbol?
631
632   // Get the appropriate symbol table header (this will normally be
633   // the single SHT_SYMTAB section, but in principle it need not be).
634   const unsigned int link = this->adjust_shndx(shdr.get_sh_link());
635   typename This::Shdr symshdr(this, this->elf_file_.section_header(link));
636
637   // Read the symbol table entry.
638   unsigned int symndx = shdr.get_sh_info();
639   if (symndx >= symshdr.get_sh_size() / This::sym_size)
640     {
641       this->error(_("section group %u info %u out of range"),
642                   index, symndx);
643       return false;
644     }
645   off_t symoff = symshdr.get_sh_offset() + symndx * This::sym_size;
646   const unsigned char* psym = this->get_view(symoff, This::sym_size, true,
647                                              false);
648   elfcpp::Sym<size, big_endian> sym(psym);
649
650   // Read the symbol table names.
651   section_size_type symnamelen;
652   const unsigned char* psymnamesu;
653   psymnamesu = this->section_contents(this->adjust_shndx(symshdr.get_sh_link()),
654                                       &symnamelen, true);
655   const char* psymnames = reinterpret_cast<const char*>(psymnamesu);
656
657   // Get the section group signature.
658   if (sym.get_st_name() >= symnamelen)
659     {
660       this->error(_("symbol %u name offset %u out of range"),
661                   symndx, sym.get_st_name());
662       return false;
663     }
664
665   std::string signature(psymnames + sym.get_st_name());
666
667   // It seems that some versions of gas will create a section group
668   // associated with a section symbol, and then fail to give a name to
669   // the section symbol.  In such a case, use the name of the section.
670   if (signature[0] == '\0' && sym.get_st_type() == elfcpp::STT_SECTION)
671     {
672       bool is_ordinary;
673       unsigned int sym_shndx = this->adjust_sym_shndx(symndx,
674                                                       sym.get_st_shndx(),
675                                                       &is_ordinary);
676       if (!is_ordinary || sym_shndx >= this->shnum())
677         {
678           this->error(_("symbol %u invalid section index %u"),
679                       symndx, sym_shndx);
680           return false;
681         }
682       typename This::Shdr member_shdr(shdrs + sym_shndx * This::shdr_size);
683       if (member_shdr.get_sh_name() < section_names_size)
684         signature = section_names + member_shdr.get_sh_name();
685     }
686
687   // Record this section group in the layout, and see whether we've already
688   // seen one with the same signature.
689   bool include_group;
690   bool is_comdat;
691   Kept_section* kept_section = NULL;
692
693   if ((flags & elfcpp::GRP_COMDAT) == 0)
694     {
695       include_group = true;
696       is_comdat = false;
697     }
698   else
699     {
700       include_group = layout->find_or_add_kept_section(signature,
701                                                        this, index, true,
702                                                        true, &kept_section);
703       is_comdat = true;
704     }
705
706   size_t count = shdr.get_sh_size() / sizeof(elfcpp::Elf_Word);
707
708   std::vector<unsigned int> shndxes;
709   bool relocate_group = include_group && parameters->options().relocatable();
710   if (relocate_group)
711     shndxes.reserve(count - 1);
712
713   for (size_t i = 1; i < count; ++i)
714     {
715       elfcpp::Elf_Word shndx =
716         this->adjust_shndx(elfcpp::Swap<32, big_endian>::readval(pword + i));
717
718       if (relocate_group)
719         shndxes.push_back(shndx);
720
721       if (shndx >= this->shnum())
722         {
723           this->error(_("section %u in section group %u out of range"),
724                       shndx, index);
725           continue;
726         }
727
728       // Check for an earlier section number, since we're going to get
729       // it wrong--we may have already decided to include the section.
730       if (shndx < index)
731         this->error(_("invalid section group %u refers to earlier section %u"),
732                     index, shndx);
733
734       // Get the name of the member section.
735       typename This::Shdr member_shdr(shdrs + shndx * This::shdr_size);
736       if (member_shdr.get_sh_name() >= section_names_size)
737         {
738           // This is an error, but it will be diagnosed eventually
739           // in do_layout, so we don't need to do anything here but
740           // ignore it.
741           continue;
742         }
743       std::string mname(section_names + member_shdr.get_sh_name());
744
745       if (include_group)
746         {
747           if (is_comdat)
748             kept_section->add_comdat_section(mname, shndx,
749                                              member_shdr.get_sh_size());
750         }
751       else
752         {
753           (*omit)[shndx] = true;
754
755           if (is_comdat)
756             {
757               Relobj* kept_object = kept_section->object();
758               if (kept_section->is_comdat())
759                 {
760                   // Find the corresponding kept section, and store
761                   // that info in the discarded section table.
762                   unsigned int kept_shndx;
763                   uint64_t kept_size;
764                   if (kept_section->find_comdat_section(mname, &kept_shndx,
765                                                         &kept_size))
766                     {
767                       // We don't keep a mapping for this section if
768                       // it has a different size.  The mapping is only
769                       // used for relocation processing, and we don't
770                       // want to treat the sections as similar if the
771                       // sizes are different.  Checking the section
772                       // size is the approach used by the GNU linker.
773                       if (kept_size == member_shdr.get_sh_size())
774                         this->set_kept_comdat_section(shndx, kept_object,
775                                                       kept_shndx);
776                     }
777                 }
778               else
779                 {
780                   // The existing section is a linkonce section.  Add
781                   // a mapping if there is exactly one section in the
782                   // group (which is true when COUNT == 2) and if it
783                   // is the same size.
784                   if (count == 2
785                       && (kept_section->linkonce_size()
786                           == member_shdr.get_sh_size()))
787                     this->set_kept_comdat_section(shndx, kept_object,
788                                                   kept_section->shndx());
789                 }
790             }
791         }
792     }
793
794   if (relocate_group)
795     layout->layout_group(symtab, this, index, name, signature.c_str(),
796                          shdr, flags, &shndxes);
797
798   return include_group;
799 }
800
801 // Whether to include a linkonce section in the link.  NAME is the
802 // name of the section and SHDR is the section header.
803
804 // Linkonce sections are a GNU extension implemented in the original
805 // GNU linker before section groups were defined.  The semantics are
806 // that we only include one linkonce section with a given name.  The
807 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
808 // where T is the type of section and SYMNAME is the name of a symbol.
809 // In an attempt to make linkonce sections interact well with section
810 // groups, we try to identify SYMNAME and use it like a section group
811 // signature.  We want to block section groups with that signature,
812 // but not other linkonce sections with that signature.  We also use
813 // the full name of the linkonce section as a normal section group
814 // signature.
815
816 template<int size, bool big_endian>
817 bool
818 Sized_relobj<size, big_endian>::include_linkonce_section(
819     Layout* layout,
820     unsigned int index,
821     const char* name,
822     const elfcpp::Shdr<size, big_endian>& shdr)
823 {
824   typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
825   // In general the symbol name we want will be the string following
826   // the last '.'.  However, we have to handle the case of
827   // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
828   // some versions of gcc.  So we use a heuristic: if the name starts
829   // with ".gnu.linkonce.t.", we use everything after that.  Otherwise
830   // we look for the last '.'.  We can't always simply skip
831   // ".gnu.linkonce.X", because we have to deal with cases like
832   // ".gnu.linkonce.d.rel.ro.local".
833   const char* const linkonce_t = ".gnu.linkonce.t.";
834   const char* symname;
835   if (strncmp(name, linkonce_t, strlen(linkonce_t)) == 0)
836     symname = name + strlen(linkonce_t);
837   else
838     symname = strrchr(name, '.') + 1;
839   std::string sig1(symname);
840   std::string sig2(name);
841   Kept_section* kept1;
842   Kept_section* kept2;
843   bool include1 = layout->find_or_add_kept_section(sig1, this, index, false,
844                                                    false, &kept1);
845   bool include2 = layout->find_or_add_kept_section(sig2, this, index, false,
846                                                    true, &kept2);
847
848   if (!include2)
849     {
850       // We are not including this section because we already saw the
851       // name of the section as a signature.  This normally implies
852       // that the kept section is another linkonce section.  If it is
853       // the same size, record it as the section which corresponds to
854       // this one.
855       if (kept2->object() != NULL
856           && !kept2->is_comdat()
857           && kept2->linkonce_size() == sh_size)
858         this->set_kept_comdat_section(index, kept2->object(), kept2->shndx());
859     }
860   else if (!include1)
861     {
862       // The section is being discarded on the basis of its symbol
863       // name.  This means that the corresponding kept section was
864       // part of a comdat group, and it will be difficult to identify
865       // the specific section within that group that corresponds to
866       // this linkonce section.  We'll handle the simple case where
867       // the group has only one member section.  Otherwise, it's not
868       // worth the effort.
869       unsigned int kept_shndx;
870       uint64_t kept_size;
871       if (kept1->object() != NULL
872           && kept1->is_comdat()
873           && kept1->find_single_comdat_section(&kept_shndx, &kept_size)
874           && kept_size == sh_size)
875         this->set_kept_comdat_section(index, kept1->object(), kept_shndx);
876     }
877   else
878     {
879       kept1->set_linkonce_size(sh_size);
880       kept2->set_linkonce_size(sh_size);
881     }
882
883   return include1 && include2;
884 }
885
886 // Layout an input section.
887
888 template<int size, bool big_endian>
889 inline void
890 Sized_relobj<size, big_endian>::layout_section(Layout* layout,
891                                                unsigned int shndx,
892                                                const char* name,
893                                                typename This::Shdr& shdr,
894                                                unsigned int reloc_shndx,
895                                                unsigned int reloc_type)
896 {
897   off_t offset;
898   Output_section* os = layout->layout(this, shndx, name, shdr,
899                                           reloc_shndx, reloc_type, &offset);
900
901   this->output_sections()[shndx] = os;
902   if (offset == -1)
903     this->section_offsets_[shndx] = invalid_address;
904   else
905     this->section_offsets_[shndx] = convert_types<Address, off_t>(offset);
906
907   // If this section requires special handling, and if there are
908   // relocs that apply to it, then we must do the special handling
909   // before we apply the relocs.
910   if (offset == -1 && reloc_shndx != 0)
911     this->set_relocs_must_follow_section_writes();
912 }
913
914 // Lay out the input sections.  We walk through the sections and check
915 // whether they should be included in the link.  If they should, we
916 // pass them to the Layout object, which will return an output section
917 // and an offset.  
918 // During garbage collection (--gc-sections) and identical code folding 
919 // (--icf), this function is called twice.  When it is called the first 
920 // time, it is for setting up some sections as roots to a work-list for
921 // --gc-sections and to do comdat processing.  Actual layout happens the 
922 // second time around after all the relevant sections have been determined.  
923 // The first time, is_worklist_ready or is_icf_ready is false. It is then 
924 // set to true after the garbage collection worklist or identical code 
925 // folding is processed and the relevant sections to be kept are 
926 // determined.  Then, this function is called again to layout the sections.
927
928 template<int size, bool big_endian>
929 void
930 Sized_relobj<size, big_endian>::do_layout(Symbol_table* symtab,
931                                           Layout* layout,
932                                           Read_symbols_data* sd)
933 {
934   const unsigned int shnum = this->shnum();
935   bool is_gc_pass_one = ((parameters->options().gc_sections() 
936                           && !symtab->gc()->is_worklist_ready())
937                          || (parameters->options().icf_enabled()
938                              && !symtab->icf()->is_icf_ready()));
939  
940   bool is_gc_pass_two = ((parameters->options().gc_sections() 
941                           && symtab->gc()->is_worklist_ready())
942                          || (parameters->options().icf_enabled()
943                              && symtab->icf()->is_icf_ready()));
944
945   bool is_gc_or_icf = (parameters->options().gc_sections()
946                        || parameters->options().icf_enabled()); 
947
948   // Both is_gc_pass_one and is_gc_pass_two should not be true.
949   gold_assert(!(is_gc_pass_one  && is_gc_pass_two));
950
951   if (shnum == 0)
952     return;
953   Symbols_data* gc_sd = NULL;
954   if (is_gc_pass_one)
955     {
956       // During garbage collection save the symbols data to use it when 
957       // re-entering this function.   
958       gc_sd = new Symbols_data;
959       this->copy_symbols_data(gc_sd, sd, This::shdr_size * shnum);
960       this->set_symbols_data(gc_sd);
961     }
962   else if (is_gc_pass_two)
963     {
964       gc_sd = this->get_symbols_data();
965     }
966
967   const unsigned char* section_headers_data = NULL;
968   section_size_type section_names_size;
969   const unsigned char* symbols_data = NULL;
970   section_size_type symbols_size;
971   section_offset_type external_symbols_offset;
972   const unsigned char* symbol_names_data = NULL;
973   section_size_type symbol_names_size;
974  
975   if (is_gc_or_icf)
976     {
977       section_headers_data = gc_sd->section_headers_data;
978       section_names_size = gc_sd->section_names_size;
979       symbols_data = gc_sd->symbols_data;
980       symbols_size = gc_sd->symbols_size;
981       external_symbols_offset = gc_sd->external_symbols_offset;
982       symbol_names_data = gc_sd->symbol_names_data;
983       symbol_names_size = gc_sd->symbol_names_size;
984     }
985   else
986     {
987       section_headers_data = sd->section_headers->data();
988       section_names_size = sd->section_names_size;
989       if (sd->symbols != NULL)
990         symbols_data = sd->symbols->data();
991       symbols_size = sd->symbols_size;
992       external_symbols_offset = sd->external_symbols_offset;
993       if (sd->symbol_names != NULL)
994         symbol_names_data = sd->symbol_names->data();
995       symbol_names_size = sd->symbol_names_size;
996     }
997
998   // Get the section headers.
999   const unsigned char* shdrs = section_headers_data;
1000   const unsigned char* pshdrs;
1001
1002   // Get the section names.
1003   const unsigned char* pnamesu = (is_gc_or_icf) 
1004                                  ? gc_sd->section_names_data
1005                                  : sd->section_names->data();
1006
1007   const char* pnames = reinterpret_cast<const char*>(pnamesu);
1008
1009   // If any input files have been claimed by plugins, we need to defer
1010   // actual layout until the replacement files have arrived.
1011   const bool should_defer_layout =
1012       (parameters->options().has_plugins()
1013        && parameters->options().plugins()->should_defer_layout());
1014   unsigned int num_sections_to_defer = 0;
1015
1016   // For each section, record the index of the reloc section if any.
1017   // Use 0 to mean that there is no reloc section, -1U to mean that
1018   // there is more than one.
1019   std::vector<unsigned int> reloc_shndx(shnum, 0);
1020   std::vector<unsigned int> reloc_type(shnum, elfcpp::SHT_NULL);
1021   // Skip the first, dummy, section.
1022   pshdrs = shdrs + This::shdr_size;
1023   for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1024     {
1025       typename This::Shdr shdr(pshdrs);
1026
1027       // Count the number of sections whose layout will be deferred.
1028       if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1029         ++num_sections_to_defer;
1030
1031       unsigned int sh_type = shdr.get_sh_type();
1032       if (sh_type == elfcpp::SHT_REL || sh_type == elfcpp::SHT_RELA)
1033         {
1034           unsigned int target_shndx = this->adjust_shndx(shdr.get_sh_info());
1035           if (target_shndx == 0 || target_shndx >= shnum)
1036             {
1037               this->error(_("relocation section %u has bad info %u"),
1038                           i, target_shndx);
1039               continue;
1040             }
1041
1042           if (reloc_shndx[target_shndx] != 0)
1043             reloc_shndx[target_shndx] = -1U;
1044           else
1045             {
1046               reloc_shndx[target_shndx] = i;
1047               reloc_type[target_shndx] = sh_type;
1048             }
1049         }
1050     }
1051
1052   Output_sections& out_sections(this->output_sections());
1053   std::vector<Address>& out_section_offsets(this->section_offsets_);
1054
1055   if (!is_gc_pass_two)
1056     {
1057       out_sections.resize(shnum);
1058       out_section_offsets.resize(shnum);
1059     }
1060
1061   // If we are only linking for symbols, then there is nothing else to
1062   // do here.
1063   if (this->input_file()->just_symbols())
1064     {
1065       if (!is_gc_pass_two)
1066         {
1067           delete sd->section_headers;
1068           sd->section_headers = NULL;
1069           delete sd->section_names;
1070           sd->section_names = NULL;
1071         }
1072       return;
1073     }
1074
1075   if (num_sections_to_defer > 0)
1076     {
1077       parameters->options().plugins()->add_deferred_layout_object(this);
1078       this->deferred_layout_.reserve(num_sections_to_defer);
1079     }
1080
1081   // Whether we've seen a .note.GNU-stack section.
1082   bool seen_gnu_stack = false;
1083   // The flags of a .note.GNU-stack section.
1084   uint64_t gnu_stack_flags = 0;
1085
1086   // Keep track of which sections to omit.
1087   std::vector<bool> omit(shnum, false);
1088
1089   // Keep track of reloc sections when emitting relocations.
1090   const bool relocatable = parameters->options().relocatable();
1091   const bool emit_relocs = (relocatable
1092                             || parameters->options().emit_relocs());
1093   std::vector<unsigned int> reloc_sections;
1094
1095   // Keep track of .eh_frame sections.
1096   std::vector<unsigned int> eh_frame_sections;
1097
1098   // Skip the first, dummy, section.
1099   pshdrs = shdrs + This::shdr_size;
1100   for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1101     {
1102       typename This::Shdr shdr(pshdrs);
1103
1104       if (shdr.get_sh_name() >= section_names_size)
1105         {
1106           this->error(_("bad section name offset for section %u: %lu"),
1107                       i, static_cast<unsigned long>(shdr.get_sh_name()));
1108           return;
1109         }
1110
1111       const char* name = pnames + shdr.get_sh_name();
1112
1113       if (!is_gc_pass_two)
1114         { 
1115           if (this->handle_gnu_warning_section(name, i, symtab))
1116             { 
1117               if (!relocatable)
1118                 omit[i] = true;
1119             }
1120
1121           // The .note.GNU-stack section is special.  It gives the
1122           // protection flags that this object file requires for the stack
1123           // in memory.
1124           if (strcmp(name, ".note.GNU-stack") == 0)
1125             {
1126               seen_gnu_stack = true;
1127               gnu_stack_flags |= shdr.get_sh_flags();
1128               omit[i] = true;
1129             }
1130
1131           // The .note.GNU-split-stack section is also special.  It
1132           // indicates that the object was compiled with
1133           // -fsplit-stack.
1134           if (this->handle_split_stack_section(name))
1135             {
1136               if (!parameters->options().relocatable()
1137                   && !parameters->options().shared())
1138                 omit[i] = true;
1139             }
1140
1141           bool discard = omit[i];
1142           if (!discard)
1143             {
1144               if (shdr.get_sh_type() == elfcpp::SHT_GROUP)
1145                 {
1146                   if (!this->include_section_group(symtab, layout, i, name, 
1147                                                    shdrs, pnames, 
1148                                                    section_names_size,
1149                                                    &omit))
1150                     discard = true;
1151                 }
1152               else if ((shdr.get_sh_flags() & elfcpp::SHF_GROUP) == 0
1153                        && Layout::is_linkonce(name))
1154                 {
1155                   if (!this->include_linkonce_section(layout, i, name, shdr))
1156                     discard = true;
1157                 }
1158             }
1159
1160           if (discard)
1161             {
1162               // Do not include this section in the link.
1163               out_sections[i] = NULL;
1164               out_section_offsets[i] = invalid_address;
1165               continue;
1166             }
1167         }
1168  
1169       if (is_gc_pass_one && parameters->options().gc_sections())
1170         {
1171           if (is_section_name_included(name)
1172               || shdr.get_sh_type() == elfcpp::SHT_INIT_ARRAY 
1173               || shdr.get_sh_type() == elfcpp::SHT_FINI_ARRAY)
1174             {
1175               symtab->gc()->worklist().push(Section_id(this, i)); 
1176             }
1177         }
1178
1179       // When doing a relocatable link we are going to copy input
1180       // reloc sections into the output.  We only want to copy the
1181       // ones associated with sections which are not being discarded.
1182       // However, we don't know that yet for all sections.  So save
1183       // reloc sections and process them later. Garbage collection is
1184       // not triggered when relocatable code is desired.
1185       if (emit_relocs
1186           && (shdr.get_sh_type() == elfcpp::SHT_REL
1187               || shdr.get_sh_type() == elfcpp::SHT_RELA))
1188         {
1189           reloc_sections.push_back(i);
1190           continue;
1191         }
1192
1193       if (relocatable && shdr.get_sh_type() == elfcpp::SHT_GROUP)
1194         continue;
1195
1196       // The .eh_frame section is special.  It holds exception frame
1197       // information that we need to read in order to generate the
1198       // exception frame header.  We process these after all the other
1199       // sections so that the exception frame reader can reliably
1200       // determine which sections are being discarded, and discard the
1201       // corresponding information.
1202       if (!relocatable
1203           && strcmp(name, ".eh_frame") == 0
1204           && this->check_eh_frame_flags(&shdr))
1205         {
1206           if (is_gc_pass_one)
1207             {
1208               out_sections[i] = reinterpret_cast<Output_section*>(1);
1209               out_section_offsets[i] = invalid_address;
1210             }
1211           else
1212             eh_frame_sections.push_back(i);
1213           continue;
1214         }
1215
1216       if (is_gc_pass_two && parameters->options().gc_sections())
1217         {
1218           // This is executed during the second pass of garbage 
1219           // collection. do_layout has been called before and some 
1220           // sections have been already discarded. Simply ignore 
1221           // such sections this time around.
1222           if (out_sections[i] == NULL)
1223             {
1224               gold_assert(out_section_offsets[i] == invalid_address);
1225               continue; 
1226             }
1227           if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1228               && symtab->gc()->is_section_garbage(this, i))
1229               {
1230                 if (parameters->options().print_gc_sections())
1231                   gold_info(_("%s: removing unused section from '%s'" 
1232                               " in file '%s'"),
1233                             program_name, this->section_name(i).c_str(), 
1234                             this->name().c_str());
1235                 out_sections[i] = NULL;
1236                 out_section_offsets[i] = invalid_address;
1237                 continue;
1238               }
1239         }
1240
1241       if (is_gc_pass_two && parameters->options().icf_enabled())
1242         {
1243           if (out_sections[i] == NULL)
1244             {
1245               gold_assert(out_section_offsets[i] == invalid_address);
1246               continue;
1247             }
1248           if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1249               && symtab->icf()->is_section_folded(this, i))
1250               {
1251                 if (parameters->options().print_icf_sections())
1252                   {
1253                     Section_id folded =
1254                                 symtab->icf()->get_folded_section(this, i);
1255                     Relobj* folded_obj =
1256                                 reinterpret_cast<Relobj*>(folded.first);
1257                     gold_info(_("%s: ICF folding section '%s' in file '%s'"
1258                                 "into '%s' in file '%s'"),
1259                               program_name, this->section_name(i).c_str(),
1260                               this->name().c_str(),
1261                               folded_obj->section_name(folded.second).c_str(),
1262                               folded_obj->name().c_str());
1263                   }
1264                 out_sections[i] = NULL;
1265                 out_section_offsets[i] = invalid_address;
1266                 continue;
1267               }
1268         }
1269
1270       // Defer layout here if input files are claimed by plugins.  When gc
1271       // is turned on this function is called twice.  For the second call
1272       // should_defer_layout should be false.
1273       if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1274         {
1275           gold_assert(!is_gc_pass_two);
1276           this->deferred_layout_.push_back(Deferred_layout(i, name, 
1277                                                            pshdrs,
1278                                                            reloc_shndx[i],
1279                                                            reloc_type[i]));
1280           // Put dummy values here; real values will be supplied by
1281           // do_layout_deferred_sections.
1282           out_sections[i] = reinterpret_cast<Output_section*>(2);
1283           out_section_offsets[i] = invalid_address;
1284           continue;
1285         }
1286
1287       // During gc_pass_two if a section that was previously deferred is
1288       // found, do not layout the section as layout_deferred_sections will
1289       // do it later from gold.cc.
1290       if (is_gc_pass_two 
1291           && (out_sections[i] == reinterpret_cast<Output_section*>(2)))
1292         continue;
1293
1294       if (is_gc_pass_one)
1295         {
1296           // This is during garbage collection. The out_sections are 
1297           // assigned in the second call to this function. 
1298           out_sections[i] = reinterpret_cast<Output_section*>(1);
1299           out_section_offsets[i] = invalid_address;
1300         }
1301       else
1302         {
1303           // When garbage collection is switched on the actual layout
1304           // only happens in the second call.
1305           this->layout_section(layout, i, name, shdr, reloc_shndx[i],
1306                                reloc_type[i]);
1307         }
1308     }
1309
1310   if (!is_gc_pass_one)
1311     layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags);
1312
1313   // When doing a relocatable link handle the reloc sections at the
1314   // end.  Garbage collection  and Identical Code Folding is not 
1315   // turned on for relocatable code. 
1316   if (emit_relocs)
1317     this->size_relocatable_relocs();
1318
1319   gold_assert(!(is_gc_or_icf) || reloc_sections.empty());
1320
1321   for (std::vector<unsigned int>::const_iterator p = reloc_sections.begin();
1322        p != reloc_sections.end();
1323        ++p)
1324     {
1325       unsigned int i = *p;
1326       const unsigned char* pshdr;
1327       pshdr = section_headers_data + i * This::shdr_size;
1328       typename This::Shdr shdr(pshdr);
1329
1330       unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1331       if (data_shndx >= shnum)
1332         {
1333           // We already warned about this above.
1334           continue;
1335         }
1336
1337       Output_section* data_section = out_sections[data_shndx];
1338       if (data_section == NULL)
1339         {
1340           out_sections[i] = NULL;
1341           out_section_offsets[i] = invalid_address;
1342           continue;
1343         }
1344
1345       Relocatable_relocs* rr = new Relocatable_relocs();
1346       this->set_relocatable_relocs(i, rr);
1347
1348       Output_section* os = layout->layout_reloc(this, i, shdr, data_section,
1349                                                 rr);
1350       out_sections[i] = os;
1351       out_section_offsets[i] = invalid_address;
1352     }
1353
1354   // Handle the .eh_frame sections at the end.
1355   gold_assert(!is_gc_pass_one || eh_frame_sections.empty());
1356   for (std::vector<unsigned int>::const_iterator p = eh_frame_sections.begin();
1357        p != eh_frame_sections.end();
1358        ++p)
1359     {
1360       gold_assert(this->has_eh_frame_);
1361       gold_assert(external_symbols_offset != 0);
1362
1363       unsigned int i = *p;
1364       const unsigned char *pshdr;
1365       pshdr = section_headers_data + i * This::shdr_size;
1366       typename This::Shdr shdr(pshdr);
1367
1368       off_t offset;
1369       Output_section* os = layout->layout_eh_frame(this,
1370                                                    symbols_data,
1371                                                    symbols_size,
1372                                                    symbol_names_data,
1373                                                    symbol_names_size,
1374                                                    i, shdr,
1375                                                    reloc_shndx[i],
1376                                                    reloc_type[i],
1377                                                    &offset);
1378       out_sections[i] = os;
1379       if (offset == -1)
1380         {
1381           // An object can contain at most one section holding exception
1382           // frame information.
1383           gold_assert(this->discarded_eh_frame_shndx_ == -1U);
1384           this->discarded_eh_frame_shndx_ = i;
1385           out_section_offsets[i] = invalid_address;
1386         }
1387       else
1388         out_section_offsets[i] = convert_types<Address, off_t>(offset);
1389
1390       // If this section requires special handling, and if there are
1391       // relocs that apply to it, then we must do the special handling
1392       // before we apply the relocs.
1393       if (offset == -1 && reloc_shndx[i] != 0)
1394         this->set_relocs_must_follow_section_writes();
1395     }
1396
1397   if (is_gc_pass_two)
1398     {
1399       delete[] gc_sd->section_headers_data;
1400       delete[] gc_sd->section_names_data;
1401       delete[] gc_sd->symbols_data;
1402       delete[] gc_sd->symbol_names_data;
1403       this->set_symbols_data(NULL);
1404     }
1405   else
1406     {
1407       delete sd->section_headers;
1408       sd->section_headers = NULL;
1409       delete sd->section_names;
1410       sd->section_names = NULL;
1411     }
1412 }
1413
1414 // Layout sections whose layout was deferred while waiting for
1415 // input files from a plugin.
1416
1417 template<int size, bool big_endian>
1418 void
1419 Sized_relobj<size, big_endian>::do_layout_deferred_sections(Layout* layout)
1420 {
1421   typename std::vector<Deferred_layout>::iterator deferred;
1422
1423   for (deferred = this->deferred_layout_.begin();
1424        deferred != this->deferred_layout_.end();
1425        ++deferred)
1426     {
1427       typename This::Shdr shdr(deferred->shdr_data_);
1428       this->layout_section(layout, deferred->shndx_, deferred->name_.c_str(),
1429                            shdr, deferred->reloc_shndx_, deferred->reloc_type_);
1430     }
1431
1432   this->deferred_layout_.clear();
1433 }
1434
1435 // Add the symbols to the symbol table.
1436
1437 template<int size, bool big_endian>
1438 void
1439 Sized_relobj<size, big_endian>::do_add_symbols(Symbol_table* symtab,
1440                                                Read_symbols_data* sd,
1441                                                Layout*)
1442 {
1443   if (sd->symbols == NULL)
1444     {
1445       gold_assert(sd->symbol_names == NULL);
1446       return;
1447     }
1448
1449   const int sym_size = This::sym_size;
1450   size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1451                      / sym_size);
1452   if (symcount * sym_size != sd->symbols_size - sd->external_symbols_offset)
1453     {
1454       this->error(_("size of symbols is not multiple of symbol size"));
1455       return;
1456     }
1457
1458   this->symbols_.resize(symcount);
1459
1460   const char* sym_names =
1461     reinterpret_cast<const char*>(sd->symbol_names->data());
1462   symtab->add_from_relobj(this,
1463                           sd->symbols->data() + sd->external_symbols_offset,
1464                           symcount, this->local_symbol_count_,
1465                           sym_names, sd->symbol_names_size,
1466                           &this->symbols_,
1467                           &this->defined_count_);
1468
1469   delete sd->symbols;
1470   sd->symbols = NULL;
1471   delete sd->symbol_names;
1472   sd->symbol_names = NULL;
1473 }
1474
1475 // First pass over the local symbols.  Here we add their names to
1476 // *POOL and *DYNPOOL, and we store the symbol value in
1477 // THIS->LOCAL_VALUES_.  This function is always called from a
1478 // singleton thread.  This is followed by a call to
1479 // finalize_local_symbols.
1480
1481 template<int size, bool big_endian>
1482 void
1483 Sized_relobj<size, big_endian>::do_count_local_symbols(Stringpool* pool,
1484                                                        Stringpool* dynpool)
1485 {
1486   gold_assert(this->symtab_shndx_ != -1U);
1487   if (this->symtab_shndx_ == 0)
1488     {
1489       // This object has no symbols.  Weird but legal.
1490       return;
1491     }
1492
1493   // Read the symbol table section header.
1494   const unsigned int symtab_shndx = this->symtab_shndx_;
1495   typename This::Shdr symtabshdr(this,
1496                                  this->elf_file_.section_header(symtab_shndx));
1497   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1498
1499   // Read the local symbols.
1500   const int sym_size = This::sym_size;
1501   const unsigned int loccount = this->local_symbol_count_;
1502   gold_assert(loccount == symtabshdr.get_sh_info());
1503   off_t locsize = loccount * sym_size;
1504   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1505                                               locsize, true, true);
1506
1507   // Read the symbol names.
1508   const unsigned int strtab_shndx =
1509     this->adjust_shndx(symtabshdr.get_sh_link());
1510   section_size_type strtab_size;
1511   const unsigned char* pnamesu = this->section_contents(strtab_shndx,
1512                                                         &strtab_size,
1513                                                         true);
1514   const char* pnames = reinterpret_cast<const char*>(pnamesu);
1515
1516   // Loop over the local symbols.
1517
1518   const Output_sections& out_sections(this->output_sections());
1519   unsigned int shnum = this->shnum();
1520   unsigned int count = 0;
1521   unsigned int dyncount = 0;
1522   // Skip the first, dummy, symbol.
1523   psyms += sym_size;
1524   bool discard_locals = parameters->options().discard_locals();
1525   for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
1526     {
1527       elfcpp::Sym<size, big_endian> sym(psyms);
1528
1529       Symbol_value<size>& lv(this->local_values_[i]);
1530
1531       bool is_ordinary;
1532       unsigned int shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
1533                                                   &is_ordinary);
1534       lv.set_input_shndx(shndx, is_ordinary);
1535
1536       if (sym.get_st_type() == elfcpp::STT_SECTION)
1537         lv.set_is_section_symbol();
1538       else if (sym.get_st_type() == elfcpp::STT_TLS)
1539         lv.set_is_tls_symbol();
1540
1541       // Save the input symbol value for use in do_finalize_local_symbols().
1542       lv.set_input_value(sym.get_st_value());
1543
1544       // Decide whether this symbol should go into the output file.
1545
1546       if ((shndx < shnum && out_sections[shndx] == NULL)
1547           || (shndx == this->discarded_eh_frame_shndx_))
1548         {
1549           lv.set_no_output_symtab_entry();
1550           gold_assert(!lv.needs_output_dynsym_entry());
1551           continue;
1552         }
1553
1554       if (sym.get_st_type() == elfcpp::STT_SECTION)
1555         {
1556           lv.set_no_output_symtab_entry();
1557           gold_assert(!lv.needs_output_dynsym_entry());
1558           continue;
1559         }
1560
1561       if (sym.get_st_name() >= strtab_size)
1562         {
1563           this->error(_("local symbol %u section name out of range: %u >= %u"),
1564                       i, sym.get_st_name(),
1565                       static_cast<unsigned int>(strtab_size));
1566           lv.set_no_output_symtab_entry();
1567           continue;
1568         }
1569
1570       // If --discard-locals option is used, discard all temporary local
1571       // symbols.  These symbols start with system-specific local label
1572       // prefixes, typically .L for ELF system.  We want to be compatible
1573       // with GNU ld so here we essentially use the same check in
1574       // bfd_is_local_label().  The code is different because we already
1575       // know that:
1576       //
1577       //   - the symbol is local and thus cannot have global or weak binding.
1578       //   - the symbol is not a section symbol.
1579       //   - the symbol has a name.
1580       //
1581       // We do not discard a symbol if it needs a dynamic symbol entry.
1582       const char* name = pnames + sym.get_st_name();
1583       if (discard_locals
1584           && sym.get_st_type() != elfcpp::STT_FILE
1585           && !lv.needs_output_dynsym_entry()
1586           && parameters->target().is_local_label_name(name))
1587         {
1588           lv.set_no_output_symtab_entry();
1589           continue;
1590         }
1591
1592       // Discard the local symbol if -retain_symbols_file is specified
1593       // and the local symbol is not in that file.
1594       if (!parameters->options().should_retain_symbol(name))
1595         {
1596           lv.set_no_output_symtab_entry();
1597           continue;
1598         }
1599
1600       // Add the symbol to the symbol table string pool.
1601       pool->add(name, true, NULL);
1602       ++count;
1603
1604       // If needed, add the symbol to the dynamic symbol table string pool.
1605       if (lv.needs_output_dynsym_entry())
1606         {
1607           dynpool->add(name, true, NULL);
1608           ++dyncount;
1609         }
1610     }
1611
1612   this->output_local_symbol_count_ = count;
1613   this->output_local_dynsym_count_ = dyncount;
1614 }
1615
1616 // Finalize the local symbols.  Here we set the final value in
1617 // THIS->LOCAL_VALUES_ and set their output symbol table indexes.
1618 // This function is always called from a singleton thread.  The actual
1619 // output of the local symbols will occur in a separate task.
1620
1621 template<int size, bool big_endian>
1622 unsigned int
1623 Sized_relobj<size, big_endian>::do_finalize_local_symbols(unsigned int index,
1624                                                           off_t off,
1625                                                           Symbol_table* symtab)
1626 {
1627   gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
1628
1629   const unsigned int loccount = this->local_symbol_count_;
1630   this->local_symbol_offset_ = off;
1631
1632   const bool relocatable = parameters->options().relocatable();
1633   const Output_sections& out_sections(this->output_sections());
1634   const std::vector<Address>& out_offsets(this->section_offsets_);
1635   unsigned int shnum = this->shnum();
1636
1637   for (unsigned int i = 1; i < loccount; ++i)
1638     {
1639       Symbol_value<size>& lv(this->local_values_[i]);
1640
1641       bool is_ordinary;
1642       unsigned int shndx = lv.input_shndx(&is_ordinary);
1643
1644       // Set the output symbol value.
1645
1646       if (!is_ordinary)
1647         {
1648           if (shndx == elfcpp::SHN_ABS || Symbol::is_common_shndx(shndx))
1649             lv.set_output_value(lv.input_value());
1650           else
1651             {
1652               this->error(_("unknown section index %u for local symbol %u"),
1653                           shndx, i);
1654               lv.set_output_value(0);
1655             }
1656         }
1657       else
1658         {
1659           if (shndx >= shnum)
1660             {
1661               this->error(_("local symbol %u section index %u out of range"),
1662                           i, shndx);
1663               shndx = 0;
1664             }
1665
1666           Output_section* os = out_sections[shndx];
1667           Address secoffset = out_offsets[shndx];
1668           if (symtab->is_section_folded(this, shndx))
1669             {
1670               gold_assert (os == NULL && secoffset == invalid_address);
1671               // Get the os of the section it is folded onto.
1672               Section_id folded = symtab->icf()->get_folded_section(this,
1673                                                                     shndx);
1674               gold_assert(folded.first != NULL);
1675               Sized_relobj<size, big_endian>* folded_obj = reinterpret_cast
1676                 <Sized_relobj<size, big_endian>*>(folded.first);
1677               os = folded_obj->output_section(folded.second);
1678               gold_assert(os != NULL);
1679               secoffset = folded_obj->get_output_section_offset(folded.second);
1680               gold_assert(secoffset != invalid_address);
1681             }
1682
1683           if (os == NULL)
1684             {
1685               // This local symbol belongs to a section we are discarding.
1686               // In some cases when applying relocations later, we will
1687               // attempt to match it to the corresponding kept section,
1688               // so we leave the input value unchanged here.
1689               continue;
1690             }
1691           else if (secoffset == invalid_address)
1692             {
1693               uint64_t start;
1694
1695               // This is a SHF_MERGE section or one which otherwise
1696               // requires special handling.
1697               if (shndx == this->discarded_eh_frame_shndx_)
1698                 {
1699                   // This local symbol belongs to a discarded .eh_frame
1700                   // section.  Just treat it like the case in which
1701                   // os == NULL above.
1702                   gold_assert(this->has_eh_frame_);
1703                   continue;
1704                 }
1705               else if (!lv.is_section_symbol())
1706                 {
1707                   // This is not a section symbol.  We can determine
1708                   // the final value now.
1709                   lv.set_output_value(os->output_address(this, shndx,
1710                                                          lv.input_value()));
1711                 }
1712               else if (!os->find_starting_output_address(this, shndx, &start))
1713                 {
1714                   // This is a section symbol, but apparently not one in a
1715                   // merged section.  First check to see if this is a relaxed
1716                   // input section.  If so, use its address.  Otherwise just
1717                   // use the start of the output section.  This happens with
1718                   // relocatable links when the input object has section
1719                   // symbols for arbitrary non-merge sections.
1720                   const Output_section_data* posd =
1721                     os->find_relaxed_input_section(this, shndx);
1722                   if (posd != NULL)
1723                     lv.set_output_value(posd->address());
1724                   else
1725                     lv.set_output_value(os->address());
1726                 }
1727               else
1728                 {
1729                   // We have to consider the addend to determine the
1730                   // value to use in a relocation.  START is the start
1731                   // of this input section.
1732                   Merged_symbol_value<size>* msv =
1733                     new Merged_symbol_value<size>(lv.input_value(), start);
1734                   lv.set_merged_symbol_value(msv);
1735                 }
1736             }
1737           else if (lv.is_tls_symbol())
1738             lv.set_output_value(os->tls_offset()
1739                                 + secoffset
1740                                 + lv.input_value());
1741           else
1742             lv.set_output_value((relocatable ? 0 : os->address())
1743                                 + secoffset
1744                                 + lv.input_value());
1745         }
1746
1747       if (lv.needs_output_symtab_entry())
1748         {
1749           lv.set_output_symtab_index(index);
1750           ++index;
1751         }
1752     }
1753   return index;
1754 }
1755
1756 // Set the output dynamic symbol table indexes for the local variables.
1757
1758 template<int size, bool big_endian>
1759 unsigned int
1760 Sized_relobj<size, big_endian>::do_set_local_dynsym_indexes(unsigned int index)
1761 {
1762   const unsigned int loccount = this->local_symbol_count_;
1763   for (unsigned int i = 1; i < loccount; ++i)
1764     {
1765       Symbol_value<size>& lv(this->local_values_[i]);
1766       if (lv.needs_output_dynsym_entry())
1767         {
1768           lv.set_output_dynsym_index(index);
1769           ++index;
1770         }
1771     }
1772   return index;
1773 }
1774
1775 // Set the offset where local dynamic symbol information will be stored.
1776 // Returns the count of local symbols contributed to the symbol table by
1777 // this object.
1778
1779 template<int size, bool big_endian>
1780 unsigned int
1781 Sized_relobj<size, big_endian>::do_set_local_dynsym_offset(off_t off)
1782 {
1783   gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
1784   this->local_dynsym_offset_ = off;
1785   return this->output_local_dynsym_count_;
1786 }
1787
1788 // If Symbols_data is not NULL get the section flags from here otherwise
1789 // get it from the file.
1790
1791 template<int size, bool big_endian>
1792 uint64_t
1793 Sized_relobj<size, big_endian>::do_section_flags(unsigned int shndx)
1794 {
1795   Symbols_data* sd = this->get_symbols_data();
1796   if (sd != NULL)
1797     {
1798       const unsigned char* pshdrs = sd->section_headers_data
1799                                     + This::shdr_size * shndx;
1800       typename This::Shdr shdr(pshdrs);
1801       return shdr.get_sh_flags(); 
1802     }
1803   // If sd is NULL, read the section header from the file.
1804   return this->elf_file_.section_flags(shndx); 
1805 }
1806
1807 // Get the section's ent size from Symbols_data.  Called by get_section_contents
1808 // in icf.cc
1809
1810 template<int size, bool big_endian>
1811 uint64_t
1812 Sized_relobj<size, big_endian>::do_section_entsize(unsigned int shndx)
1813 {
1814   Symbols_data* sd = this->get_symbols_data();
1815   gold_assert (sd != NULL);
1816
1817   const unsigned char* pshdrs = sd->section_headers_data
1818                                 + This::shdr_size * shndx;
1819   typename This::Shdr shdr(pshdrs);
1820   return shdr.get_sh_entsize(); 
1821 }
1822
1823
1824 // Write out the local symbols.
1825
1826 template<int size, bool big_endian>
1827 void
1828 Sized_relobj<size, big_endian>::write_local_symbols(
1829     Output_file* of,
1830     const Stringpool* sympool,
1831     const Stringpool* dynpool,
1832     Output_symtab_xindex* symtab_xindex,
1833     Output_symtab_xindex* dynsym_xindex)
1834 {
1835   const bool strip_all = parameters->options().strip_all();
1836   if (strip_all)
1837     {
1838       if (this->output_local_dynsym_count_ == 0)
1839         return;
1840       this->output_local_symbol_count_ = 0;
1841     }
1842
1843   gold_assert(this->symtab_shndx_ != -1U);
1844   if (this->symtab_shndx_ == 0)
1845     {
1846       // This object has no symbols.  Weird but legal.
1847       return;
1848     }
1849
1850   // Read the symbol table section header.
1851   const unsigned int symtab_shndx = this->symtab_shndx_;
1852   typename This::Shdr symtabshdr(this,
1853                                  this->elf_file_.section_header(symtab_shndx));
1854   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1855   const unsigned int loccount = this->local_symbol_count_;
1856   gold_assert(loccount == symtabshdr.get_sh_info());
1857
1858   // Read the local symbols.
1859   const int sym_size = This::sym_size;
1860   off_t locsize = loccount * sym_size;
1861   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1862                                               locsize, true, false);
1863
1864   // Read the symbol names.
1865   const unsigned int strtab_shndx =
1866     this->adjust_shndx(symtabshdr.get_sh_link());
1867   section_size_type strtab_size;
1868   const unsigned char* pnamesu = this->section_contents(strtab_shndx,
1869                                                         &strtab_size,
1870                                                         false);
1871   const char* pnames = reinterpret_cast<const char*>(pnamesu);
1872
1873   // Get views into the output file for the portions of the symbol table
1874   // and the dynamic symbol table that we will be writing.
1875   off_t output_size = this->output_local_symbol_count_ * sym_size;
1876   unsigned char* oview = NULL;
1877   if (output_size > 0)
1878     oview = of->get_output_view(this->local_symbol_offset_, output_size);
1879
1880   off_t dyn_output_size = this->output_local_dynsym_count_ * sym_size;
1881   unsigned char* dyn_oview = NULL;
1882   if (dyn_output_size > 0)
1883     dyn_oview = of->get_output_view(this->local_dynsym_offset_,
1884                                     dyn_output_size);
1885
1886   const Output_sections out_sections(this->output_sections());
1887
1888   gold_assert(this->local_values_.size() == loccount);
1889
1890   unsigned char* ov = oview;
1891   unsigned char* dyn_ov = dyn_oview;
1892   psyms += sym_size;
1893   for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
1894     {
1895       elfcpp::Sym<size, big_endian> isym(psyms);
1896
1897       Symbol_value<size>& lv(this->local_values_[i]);
1898
1899       bool is_ordinary;
1900       unsigned int st_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
1901                                                      &is_ordinary);
1902       if (is_ordinary)
1903         {
1904           gold_assert(st_shndx < out_sections.size());
1905           if (out_sections[st_shndx] == NULL)
1906             continue;
1907           st_shndx = out_sections[st_shndx]->out_shndx();
1908           if (st_shndx >= elfcpp::SHN_LORESERVE)
1909             {
1910               if (lv.needs_output_symtab_entry() && !strip_all)
1911                 symtab_xindex->add(lv.output_symtab_index(), st_shndx);
1912               if (lv.needs_output_dynsym_entry())
1913                 dynsym_xindex->add(lv.output_dynsym_index(), st_shndx);
1914               st_shndx = elfcpp::SHN_XINDEX;
1915             }
1916         }
1917
1918       // Write the symbol to the output symbol table.
1919       if (!strip_all && lv.needs_output_symtab_entry())
1920         {
1921           elfcpp::Sym_write<size, big_endian> osym(ov);
1922
1923           gold_assert(isym.get_st_name() < strtab_size);
1924           const char* name = pnames + isym.get_st_name();
1925           osym.put_st_name(sympool->get_offset(name));
1926           osym.put_st_value(this->local_values_[i].value(this, 0));
1927           osym.put_st_size(isym.get_st_size());
1928           osym.put_st_info(isym.get_st_info());
1929           osym.put_st_other(isym.get_st_other());
1930           osym.put_st_shndx(st_shndx);
1931
1932           ov += sym_size;
1933         }
1934
1935       // Write the symbol to the output dynamic symbol table.
1936       if (lv.needs_output_dynsym_entry())
1937         {
1938           gold_assert(dyn_ov < dyn_oview + dyn_output_size);
1939           elfcpp::Sym_write<size, big_endian> osym(dyn_ov);
1940
1941           gold_assert(isym.get_st_name() < strtab_size);
1942           const char* name = pnames + isym.get_st_name();
1943           osym.put_st_name(dynpool->get_offset(name));
1944           osym.put_st_value(this->local_values_[i].value(this, 0));
1945           osym.put_st_size(isym.get_st_size());
1946           osym.put_st_info(isym.get_st_info());
1947           osym.put_st_other(isym.get_st_other());
1948           osym.put_st_shndx(st_shndx);
1949
1950           dyn_ov += sym_size;
1951         }
1952     }
1953
1954
1955   if (output_size > 0)
1956     {
1957       gold_assert(ov - oview == output_size);
1958       of->write_output_view(this->local_symbol_offset_, output_size, oview);
1959     }
1960
1961   if (dyn_output_size > 0)
1962     {
1963       gold_assert(dyn_ov - dyn_oview == dyn_output_size);
1964       of->write_output_view(this->local_dynsym_offset_, dyn_output_size,
1965                             dyn_oview);
1966     }
1967 }
1968
1969 // Set *INFO to symbolic information about the offset OFFSET in the
1970 // section SHNDX.  Return true if we found something, false if we
1971 // found nothing.
1972
1973 template<int size, bool big_endian>
1974 bool
1975 Sized_relobj<size, big_endian>::get_symbol_location_info(
1976     unsigned int shndx,
1977     off_t offset,
1978     Symbol_location_info* info)
1979 {
1980   if (this->symtab_shndx_ == 0)
1981     return false;
1982
1983   section_size_type symbols_size;
1984   const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
1985                                                         &symbols_size,
1986                                                         false);
1987
1988   unsigned int symbol_names_shndx =
1989     this->adjust_shndx(this->section_link(this->symtab_shndx_));
1990   section_size_type names_size;
1991   const unsigned char* symbol_names_u =
1992     this->section_contents(symbol_names_shndx, &names_size, false);
1993   const char* symbol_names = reinterpret_cast<const char*>(symbol_names_u);
1994
1995   const int sym_size = This::sym_size;
1996   const size_t count = symbols_size / sym_size;
1997
1998   const unsigned char* p = symbols;
1999   for (size_t i = 0; i < count; ++i, p += sym_size)
2000     {
2001       elfcpp::Sym<size, big_endian> sym(p);
2002
2003       if (sym.get_st_type() == elfcpp::STT_FILE)
2004         {
2005           if (sym.get_st_name() >= names_size)
2006             info->source_file = "(invalid)";
2007           else
2008             info->source_file = symbol_names + sym.get_st_name();
2009           continue;
2010         }
2011
2012       bool is_ordinary;
2013       unsigned int st_shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
2014                                                      &is_ordinary);
2015       if (is_ordinary
2016           && st_shndx == shndx
2017           && static_cast<off_t>(sym.get_st_value()) <= offset
2018           && (static_cast<off_t>(sym.get_st_value() + sym.get_st_size())
2019               > offset))
2020         {
2021           if (sym.get_st_name() > names_size)
2022             info->enclosing_symbol_name = "(invalid)";
2023           else
2024             {
2025               info->enclosing_symbol_name = symbol_names + sym.get_st_name();
2026               if (parameters->options().do_demangle())
2027                 {
2028                   char* demangled_name = cplus_demangle(
2029                       info->enclosing_symbol_name.c_str(),
2030                       DMGL_ANSI | DMGL_PARAMS);
2031                   if (demangled_name != NULL)
2032                     {
2033                       info->enclosing_symbol_name.assign(demangled_name);
2034                       free(demangled_name);
2035                     }
2036                 }
2037             }
2038           return true;
2039         }
2040     }
2041
2042   return false;
2043 }
2044
2045 // Look for a kept section corresponding to the given discarded section,
2046 // and return its output address.  This is used only for relocations in
2047 // debugging sections.  If we can't find the kept section, return 0.
2048
2049 template<int size, bool big_endian>
2050 typename Sized_relobj<size, big_endian>::Address
2051 Sized_relobj<size, big_endian>::map_to_kept_section(
2052     unsigned int shndx,
2053     bool* found) const
2054 {
2055   Relobj* kept_object;
2056   unsigned int kept_shndx;
2057   if (this->get_kept_comdat_section(shndx, &kept_object, &kept_shndx))
2058     {
2059       Sized_relobj<size, big_endian>* kept_relobj =
2060         static_cast<Sized_relobj<size, big_endian>*>(kept_object);
2061       Output_section* os = kept_relobj->output_section(kept_shndx);
2062       Address offset = kept_relobj->get_output_section_offset(kept_shndx);
2063       if (os != NULL && offset != invalid_address)
2064         {
2065           *found = true;
2066           return os->address() + offset;
2067         }
2068     }
2069   *found = false;
2070   return 0;
2071 }
2072
2073 // Get symbol counts.
2074
2075 template<int size, bool big_endian>
2076 void
2077 Sized_relobj<size, big_endian>::do_get_global_symbol_counts(
2078     const Symbol_table*,
2079     size_t* defined,
2080     size_t* used) const
2081 {
2082   *defined = this->defined_count_;
2083   size_t count = 0;
2084   for (Symbols::const_iterator p = this->symbols_.begin();
2085        p != this->symbols_.end();
2086        ++p)
2087     if (*p != NULL
2088         && (*p)->source() == Symbol::FROM_OBJECT
2089         && (*p)->object() == this
2090         && (*p)->is_defined())
2091       ++count;
2092   *used = count;
2093 }
2094
2095 // Input_objects methods.
2096
2097 // Add a regular relocatable object to the list.  Return false if this
2098 // object should be ignored.
2099
2100 bool
2101 Input_objects::add_object(Object* obj)
2102 {
2103   // Print the filename if the -t/--trace option is selected.
2104   if (parameters->options().trace())
2105     gold_info("%s", obj->name().c_str());
2106
2107   if (!obj->is_dynamic())
2108     this->relobj_list_.push_back(static_cast<Relobj*>(obj));
2109   else
2110     {
2111       // See if this is a duplicate SONAME.
2112       Dynobj* dynobj = static_cast<Dynobj*>(obj);
2113       const char* soname = dynobj->soname();
2114
2115       std::pair<Unordered_set<std::string>::iterator, bool> ins =
2116         this->sonames_.insert(soname);
2117       if (!ins.second)
2118         {
2119           // We have already seen a dynamic object with this soname.
2120           return false;
2121         }
2122
2123       this->dynobj_list_.push_back(dynobj);
2124     }
2125
2126   // Add this object to the cross-referencer if requested.
2127   if (parameters->options().user_set_print_symbol_counts())
2128     {
2129       if (this->cref_ == NULL)
2130         this->cref_ = new Cref();
2131       this->cref_->add_object(obj);
2132     }
2133
2134   return true;
2135 }
2136
2137 // For each dynamic object, record whether we've seen all of its
2138 // explicit dependencies.
2139
2140 void
2141 Input_objects::check_dynamic_dependencies() const
2142 {
2143   for (Dynobj_list::const_iterator p = this->dynobj_list_.begin();
2144        p != this->dynobj_list_.end();
2145        ++p)
2146     {
2147       const Dynobj::Needed& needed((*p)->needed());
2148       bool found_all = true;
2149       for (Dynobj::Needed::const_iterator pneeded = needed.begin();
2150            pneeded != needed.end();
2151            ++pneeded)
2152         {
2153           if (this->sonames_.find(*pneeded) == this->sonames_.end())
2154             {
2155               found_all = false;
2156               break;
2157             }
2158         }
2159       (*p)->set_has_unknown_needed_entries(!found_all);
2160     }
2161 }
2162
2163 // Start processing an archive.
2164
2165 void
2166 Input_objects::archive_start(Archive* archive)
2167 {
2168   if (parameters->options().user_set_print_symbol_counts())
2169     {
2170       if (this->cref_ == NULL)
2171         this->cref_ = new Cref();
2172       this->cref_->add_archive_start(archive);
2173     }
2174 }
2175
2176 // Stop processing an archive.
2177
2178 void
2179 Input_objects::archive_stop(Archive* archive)
2180 {
2181   if (parameters->options().user_set_print_symbol_counts())
2182     this->cref_->add_archive_stop(archive);
2183 }
2184
2185 // Print symbol counts
2186
2187 void
2188 Input_objects::print_symbol_counts(const Symbol_table* symtab) const
2189 {
2190   if (parameters->options().user_set_print_symbol_counts()
2191       && this->cref_ != NULL)
2192     this->cref_->print_symbol_counts(symtab);
2193 }
2194
2195 // Relocate_info methods.
2196
2197 // Return a string describing the location of a relocation.  This is
2198 // only used in error messages.
2199
2200 template<int size, bool big_endian>
2201 std::string
2202 Relocate_info<size, big_endian>::location(size_t, off_t offset) const
2203 {
2204   // See if we can get line-number information from debugging sections.
2205   std::string filename;
2206   std::string file_and_lineno;   // Better than filename-only, if available.
2207
2208   Sized_dwarf_line_info<size, big_endian> line_info(this->object);
2209   // This will be "" if we failed to parse the debug info for any reason.
2210   file_and_lineno = line_info.addr2line(this->data_shndx, offset);
2211
2212   std::string ret(this->object->name());
2213   ret += ':';
2214   Symbol_location_info info;
2215   if (this->object->get_symbol_location_info(this->data_shndx, offset, &info))
2216     {
2217       ret += " in function ";
2218       ret += info.enclosing_symbol_name;
2219       ret += ":";
2220       filename = info.source_file;
2221     }
2222
2223   if (!file_and_lineno.empty())
2224     ret += file_and_lineno;
2225   else
2226     {
2227       if (!filename.empty())
2228         ret += filename;
2229       ret += "(";
2230       ret += this->object->section_name(this->data_shndx);
2231       char buf[100];
2232       // Offsets into sections have to be positive.
2233       snprintf(buf, sizeof(buf), "+0x%lx", static_cast<long>(offset));
2234       ret += buf;
2235       ret += ")";
2236     }
2237   return ret;
2238 }
2239
2240 } // End namespace gold.
2241
2242 namespace
2243 {
2244
2245 using namespace gold;
2246
2247 // Read an ELF file with the header and return the appropriate
2248 // instance of Object.
2249
2250 template<int size, bool big_endian>
2251 Object*
2252 make_elf_sized_object(const std::string& name, Input_file* input_file,
2253                       off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr,
2254                       bool* punconfigured)
2255 {
2256   Target* target = select_target(ehdr.get_e_machine(), size, big_endian,
2257                                  ehdr.get_e_ident()[elfcpp::EI_OSABI],
2258                                  ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
2259   if (target == NULL)
2260     gold_fatal(_("%s: unsupported ELF machine number %d"),
2261                name.c_str(), ehdr.get_e_machine());
2262
2263   if (!parameters->target_valid())
2264     set_parameters_target(target);
2265   else if (target != &parameters->target())
2266     {
2267       if (punconfigured != NULL)
2268         *punconfigured = true;
2269       else
2270         gold_error(_("%s: incompatible target"), name.c_str());
2271       return NULL;
2272     }
2273
2274   return target->make_elf_object<size, big_endian>(name, input_file, offset,
2275                                                    ehdr);
2276 }
2277
2278 } // End anonymous namespace.
2279
2280 namespace gold
2281 {
2282
2283 // Return whether INPUT_FILE is an ELF object.
2284
2285 bool
2286 is_elf_object(Input_file* input_file, off_t offset,
2287               const unsigned char** start, int *read_size)
2288 {
2289   off_t filesize = input_file->file().filesize();
2290   int want = elfcpp::Elf_recognizer::max_header_size;
2291   if (filesize - offset < want)
2292     want = filesize - offset;
2293
2294   const unsigned char* p = input_file->file().get_view(offset, 0, want,
2295                                                        true, false);
2296   *start = p;
2297   *read_size = want;
2298
2299   return elfcpp::Elf_recognizer::is_elf_file(p, want);
2300 }
2301
2302 // Read an ELF file and return the appropriate instance of Object.
2303
2304 Object*
2305 make_elf_object(const std::string& name, Input_file* input_file, off_t offset,
2306                 const unsigned char* p, section_offset_type bytes,
2307                 bool* punconfigured)
2308 {
2309   if (punconfigured != NULL)
2310     *punconfigured = false;
2311
2312   std::string error;
2313   bool big_endian;
2314   int size;
2315   if (!elfcpp::Elf_recognizer::is_valid_header(p, bytes, &size,
2316                                                &big_endian, &error))
2317     {
2318       gold_error(_("%s: %s"), name.c_str(), error.c_str());
2319       return NULL;
2320     }
2321
2322   if (size == 32)
2323     {
2324       if (big_endian)
2325         {
2326 #ifdef HAVE_TARGET_32_BIG
2327           elfcpp::Ehdr<32, true> ehdr(p);
2328           return make_elf_sized_object<32, true>(name, input_file,
2329                                                  offset, ehdr, punconfigured);
2330 #else
2331           if (punconfigured != NULL)
2332             *punconfigured = true;
2333           else
2334             gold_error(_("%s: not configured to support "
2335                          "32-bit big-endian object"),
2336                        name.c_str());
2337           return NULL;
2338 #endif
2339         }
2340       else
2341         {
2342 #ifdef HAVE_TARGET_32_LITTLE
2343           elfcpp::Ehdr<32, false> ehdr(p);
2344           return make_elf_sized_object<32, false>(name, input_file,
2345                                                   offset, ehdr, punconfigured);
2346 #else
2347           if (punconfigured != NULL)
2348             *punconfigured = true;
2349           else
2350             gold_error(_("%s: not configured to support "
2351                          "32-bit little-endian object"),
2352                        name.c_str());
2353           return NULL;
2354 #endif
2355         }
2356     }
2357   else if (size == 64)
2358     {
2359       if (big_endian)
2360         {
2361 #ifdef HAVE_TARGET_64_BIG
2362           elfcpp::Ehdr<64, true> ehdr(p);
2363           return make_elf_sized_object<64, true>(name, input_file,
2364                                                  offset, ehdr, punconfigured);
2365 #else
2366           if (punconfigured != NULL)
2367             *punconfigured = true;
2368           else
2369             gold_error(_("%s: not configured to support "
2370                          "64-bit big-endian object"),
2371                        name.c_str());
2372           return NULL;
2373 #endif
2374         }
2375       else
2376         {
2377 #ifdef HAVE_TARGET_64_LITTLE
2378           elfcpp::Ehdr<64, false> ehdr(p);
2379           return make_elf_sized_object<64, false>(name, input_file,
2380                                                   offset, ehdr, punconfigured);
2381 #else
2382           if (punconfigured != NULL)
2383             *punconfigured = true;
2384           else
2385             gold_error(_("%s: not configured to support "
2386                          "64-bit little-endian object"),
2387                        name.c_str());
2388           return NULL;
2389 #endif
2390         }
2391     }
2392   else
2393     gold_unreachable();
2394 }
2395
2396 // Instantiate the templates we need.
2397
2398 #ifdef HAVE_TARGET_32_LITTLE
2399 template
2400 void
2401 Object::read_section_data<32, false>(elfcpp::Elf_file<32, false, Object>*,
2402                                      Read_symbols_data*);
2403 #endif
2404
2405 #ifdef HAVE_TARGET_32_BIG
2406 template
2407 void
2408 Object::read_section_data<32, true>(elfcpp::Elf_file<32, true, Object>*,
2409                                     Read_symbols_data*);
2410 #endif
2411
2412 #ifdef HAVE_TARGET_64_LITTLE
2413 template
2414 void
2415 Object::read_section_data<64, false>(elfcpp::Elf_file<64, false, Object>*,
2416                                      Read_symbols_data*);
2417 #endif
2418
2419 #ifdef HAVE_TARGET_64_BIG
2420 template
2421 void
2422 Object::read_section_data<64, true>(elfcpp::Elf_file<64, true, Object>*,
2423                                     Read_symbols_data*);
2424 #endif
2425
2426 #ifdef HAVE_TARGET_32_LITTLE
2427 template
2428 class Sized_relobj<32, false>;
2429 #endif
2430
2431 #ifdef HAVE_TARGET_32_BIG
2432 template
2433 class Sized_relobj<32, true>;
2434 #endif
2435
2436 #ifdef HAVE_TARGET_64_LITTLE
2437 template
2438 class Sized_relobj<64, false>;
2439 #endif
2440
2441 #ifdef HAVE_TARGET_64_BIG
2442 template
2443 class Sized_relobj<64, true>;
2444 #endif
2445
2446 #ifdef HAVE_TARGET_32_LITTLE
2447 template
2448 struct Relocate_info<32, false>;
2449 #endif
2450
2451 #ifdef HAVE_TARGET_32_BIG
2452 template
2453 struct Relocate_info<32, true>;
2454 #endif
2455
2456 #ifdef HAVE_TARGET_64_LITTLE
2457 template
2458 struct Relocate_info<64, false>;
2459 #endif
2460
2461 #ifdef HAVE_TARGET_64_BIG
2462 template
2463 struct Relocate_info<64, true>;
2464 #endif
2465
2466 } // End namespace gold.