PR ld/14265
[external/binutils.git] / gold / object.cc
1 // object.cc -- support for an object file for linking in gold
2
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012
4 // Free Software Foundation, Inc.
5 // Written by Ian Lance Taylor <iant@google.com>.
6
7 // This file is part of gold.
8
9 // This program is free software; you can redistribute it and/or modify
10 // it under the terms of the GNU General Public License as published by
11 // the Free Software Foundation; either version 3 of the License, or
12 // (at your option) any later version.
13
14 // This program is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 // GNU General Public License for more details.
18
19 // You should have received a copy of the GNU General Public License
20 // along with this program; if not, write to the Free Software
21 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22 // MA 02110-1301, USA.
23
24 #include "gold.h"
25
26 #include <cerrno>
27 #include <cstring>
28 #include <cstdarg>
29 #include "demangle.h"
30 #include "libiberty.h"
31
32 #include "gc.h"
33 #include "target-select.h"
34 #include "dwarf_reader.h"
35 #include "layout.h"
36 #include "output.h"
37 #include "symtab.h"
38 #include "cref.h"
39 #include "reloc.h"
40 #include "object.h"
41 #include "dynobj.h"
42 #include "plugin.h"
43 #include "compressed_output.h"
44 #include "incremental.h"
45
46 namespace gold
47 {
48
49 // Struct Read_symbols_data.
50
51 // Destroy any remaining File_view objects.
52
53 Read_symbols_data::~Read_symbols_data()
54 {
55   if (this->section_headers != NULL)
56     delete this->section_headers;
57   if (this->section_names != NULL)
58     delete this->section_names;
59   if (this->symbols != NULL)
60     delete this->symbols;
61   if (this->symbol_names != NULL)
62     delete this->symbol_names;
63   if (this->versym != NULL)
64     delete this->versym;
65   if (this->verdef != NULL)
66     delete this->verdef;
67   if (this->verneed != NULL)
68     delete this->verneed;
69 }
70
71 // Class Xindex.
72
73 // Initialize the symtab_xindex_ array.  Find the SHT_SYMTAB_SHNDX
74 // section and read it in.  SYMTAB_SHNDX is the index of the symbol
75 // table we care about.
76
77 template<int size, bool big_endian>
78 void
79 Xindex::initialize_symtab_xindex(Object* object, unsigned int symtab_shndx)
80 {
81   if (!this->symtab_xindex_.empty())
82     return;
83
84   gold_assert(symtab_shndx != 0);
85
86   // Look through the sections in reverse order, on the theory that it
87   // is more likely to be near the end than the beginning.
88   unsigned int i = object->shnum();
89   while (i > 0)
90     {
91       --i;
92       if (object->section_type(i) == elfcpp::SHT_SYMTAB_SHNDX
93           && this->adjust_shndx(object->section_link(i)) == symtab_shndx)
94         {
95           this->read_symtab_xindex<size, big_endian>(object, i, NULL);
96           return;
97         }
98     }
99
100   object->error(_("missing SHT_SYMTAB_SHNDX section"));
101 }
102
103 // Read in the symtab_xindex_ array, given the section index of the
104 // SHT_SYMTAB_SHNDX section.  If PSHDRS is not NULL, it points at the
105 // section headers.
106
107 template<int size, bool big_endian>
108 void
109 Xindex::read_symtab_xindex(Object* object, unsigned int xindex_shndx,
110                            const unsigned char* pshdrs)
111 {
112   section_size_type bytecount;
113   const unsigned char* contents;
114   if (pshdrs == NULL)
115     contents = object->section_contents(xindex_shndx, &bytecount, false);
116   else
117     {
118       const unsigned char* p = (pshdrs
119                                 + (xindex_shndx
120                                    * elfcpp::Elf_sizes<size>::shdr_size));
121       typename elfcpp::Shdr<size, big_endian> shdr(p);
122       bytecount = convert_to_section_size_type(shdr.get_sh_size());
123       contents = object->get_view(shdr.get_sh_offset(), bytecount, true, false);
124     }
125
126   gold_assert(this->symtab_xindex_.empty());
127   this->symtab_xindex_.reserve(bytecount / 4);
128   for (section_size_type i = 0; i < bytecount; i += 4)
129     {
130       unsigned int shndx = elfcpp::Swap<32, big_endian>::readval(contents + i);
131       // We preadjust the section indexes we save.
132       this->symtab_xindex_.push_back(this->adjust_shndx(shndx));
133     }
134 }
135
136 // Symbol symndx has a section of SHN_XINDEX; return the real section
137 // index.
138
139 unsigned int
140 Xindex::sym_xindex_to_shndx(Object* object, unsigned int symndx)
141 {
142   if (symndx >= this->symtab_xindex_.size())
143     {
144       object->error(_("symbol %u out of range for SHT_SYMTAB_SHNDX section"),
145                     symndx);
146       return elfcpp::SHN_UNDEF;
147     }
148   unsigned int shndx = this->symtab_xindex_[symndx];
149   if (shndx < elfcpp::SHN_LORESERVE || shndx >= object->shnum())
150     {
151       object->error(_("extended index for symbol %u out of range: %u"),
152                     symndx, shndx);
153       return elfcpp::SHN_UNDEF;
154     }
155   return shndx;
156 }
157
158 // Class Object.
159
160 // Report an error for this object file.  This is used by the
161 // elfcpp::Elf_file interface, and also called by the Object code
162 // itself.
163
164 void
165 Object::error(const char* format, ...) const
166 {
167   va_list args;
168   va_start(args, format);
169   char* buf = NULL;
170   if (vasprintf(&buf, format, args) < 0)
171     gold_nomem();
172   va_end(args);
173   gold_error(_("%s: %s"), this->name().c_str(), buf);
174   free(buf);
175 }
176
177 // Return a view of the contents of a section.
178
179 const unsigned char*
180 Object::section_contents(unsigned int shndx, section_size_type* plen,
181                          bool cache)
182 { return this->do_section_contents(shndx, plen, cache); }
183
184 // Read the section data into SD.  This is code common to Sized_relobj_file
185 // and Sized_dynobj, so we put it into Object.
186
187 template<int size, bool big_endian>
188 void
189 Object::read_section_data(elfcpp::Elf_file<size, big_endian, Object>* elf_file,
190                           Read_symbols_data* sd)
191 {
192   const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
193
194   // Read the section headers.
195   const off_t shoff = elf_file->shoff();
196   const unsigned int shnum = this->shnum();
197   sd->section_headers = this->get_lasting_view(shoff, shnum * shdr_size,
198                                                true, true);
199
200   // Read the section names.
201   const unsigned char* pshdrs = sd->section_headers->data();
202   const unsigned char* pshdrnames = pshdrs + elf_file->shstrndx() * shdr_size;
203   typename elfcpp::Shdr<size, big_endian> shdrnames(pshdrnames);
204
205   if (shdrnames.get_sh_type() != elfcpp::SHT_STRTAB)
206     this->error(_("section name section has wrong type: %u"),
207                 static_cast<unsigned int>(shdrnames.get_sh_type()));
208
209   sd->section_names_size =
210     convert_to_section_size_type(shdrnames.get_sh_size());
211   sd->section_names = this->get_lasting_view(shdrnames.get_sh_offset(),
212                                              sd->section_names_size, false,
213                                              false);
214 }
215
216 // If NAME is the name of a special .gnu.warning section, arrange for
217 // the warning to be issued.  SHNDX is the section index.  Return
218 // whether it is a warning section.
219
220 bool
221 Object::handle_gnu_warning_section(const char* name, unsigned int shndx,
222                                    Symbol_table* symtab)
223 {
224   const char warn_prefix[] = ".gnu.warning.";
225   const int warn_prefix_len = sizeof warn_prefix - 1;
226   if (strncmp(name, warn_prefix, warn_prefix_len) == 0)
227     {
228       // Read the section contents to get the warning text.  It would
229       // be nicer if we only did this if we have to actually issue a
230       // warning.  Unfortunately, warnings are issued as we relocate
231       // sections.  That means that we can not lock the object then,
232       // as we might try to issue the same warning multiple times
233       // simultaneously.
234       section_size_type len;
235       const unsigned char* contents = this->section_contents(shndx, &len,
236                                                              false);
237       if (len == 0)
238         {
239           const char* warning = name + warn_prefix_len;
240           contents = reinterpret_cast<const unsigned char*>(warning);
241           len = strlen(warning);
242         }
243       std::string warning(reinterpret_cast<const char*>(contents), len);
244       symtab->add_warning(name + warn_prefix_len, this, warning);
245       return true;
246     }
247   return false;
248 }
249
250 // If NAME is the name of the special section which indicates that
251 // this object was compiled with -fsplit-stack, mark it accordingly.
252
253 bool
254 Object::handle_split_stack_section(const char* name)
255 {
256   if (strcmp(name, ".note.GNU-split-stack") == 0)
257     {
258       this->uses_split_stack_ = true;
259       return true;
260     }
261   if (strcmp(name, ".note.GNU-no-split-stack") == 0)
262     {
263       this->has_no_split_stack_ = true;
264       return true;
265     }
266   return false;
267 }
268
269 // Class Relobj
270
271 // To copy the symbols data read from the file to a local data structure.
272 // This function is called from do_layout only while doing garbage
273 // collection.
274
275 void
276 Relobj::copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd,
277                           unsigned int section_header_size)
278 {
279   gc_sd->section_headers_data =
280          new unsigned char[(section_header_size)];
281   memcpy(gc_sd->section_headers_data, sd->section_headers->data(),
282          section_header_size);
283   gc_sd->section_names_data =
284          new unsigned char[sd->section_names_size];
285   memcpy(gc_sd->section_names_data, sd->section_names->data(),
286          sd->section_names_size);
287   gc_sd->section_names_size = sd->section_names_size;
288   if (sd->symbols != NULL)
289     {
290       gc_sd->symbols_data =
291              new unsigned char[sd->symbols_size];
292       memcpy(gc_sd->symbols_data, sd->symbols->data(),
293             sd->symbols_size);
294     }
295   else
296     {
297       gc_sd->symbols_data = NULL;
298     }
299   gc_sd->symbols_size = sd->symbols_size;
300   gc_sd->external_symbols_offset = sd->external_symbols_offset;
301   if (sd->symbol_names != NULL)
302     {
303       gc_sd->symbol_names_data =
304              new unsigned char[sd->symbol_names_size];
305       memcpy(gc_sd->symbol_names_data, sd->symbol_names->data(),
306             sd->symbol_names_size);
307     }
308   else
309     {
310       gc_sd->symbol_names_data = NULL;
311     }
312   gc_sd->symbol_names_size = sd->symbol_names_size;
313 }
314
315 // This function determines if a particular section name must be included
316 // in the link.  This is used during garbage collection to determine the
317 // roots of the worklist.
318
319 bool
320 Relobj::is_section_name_included(const char* name)
321 {
322   if (is_prefix_of(".ctors", name)
323       || is_prefix_of(".dtors", name)
324       || is_prefix_of(".note", name)
325       || is_prefix_of(".init", name)
326       || is_prefix_of(".fini", name)
327       || is_prefix_of(".gcc_except_table", name)
328       || is_prefix_of(".jcr", name)
329       || is_prefix_of(".preinit_array", name)
330       || (is_prefix_of(".text", name)
331           && strstr(name, "personality"))
332       || (is_prefix_of(".data", name)
333           &&  strstr(name, "personality"))
334       || (is_prefix_of(".gnu.linkonce.d", name)
335           && strstr(name, "personality")))
336     {
337       return true;
338     }
339   return false;
340 }
341
342 // Finalize the incremental relocation information.  Allocates a block
343 // of relocation entries for each symbol, and sets the reloc_bases_
344 // array to point to the first entry in each block.  If CLEAR_COUNTS
345 // is TRUE, also clear the per-symbol relocation counters.
346
347 void
348 Relobj::finalize_incremental_relocs(Layout* layout, bool clear_counts)
349 {
350   unsigned int nsyms = this->get_global_symbols()->size();
351   this->reloc_bases_ = new unsigned int[nsyms];
352
353   gold_assert(this->reloc_bases_ != NULL);
354   gold_assert(layout->incremental_inputs() != NULL);
355
356   unsigned int rindex = layout->incremental_inputs()->get_reloc_count();
357   for (unsigned int i = 0; i < nsyms; ++i)
358     {
359       this->reloc_bases_[i] = rindex;
360       rindex += this->reloc_counts_[i];
361       if (clear_counts)
362         this->reloc_counts_[i] = 0;
363     }
364   layout->incremental_inputs()->set_reloc_count(rindex);
365 }
366
367 // Class Sized_relobj.
368
369 // Iterate over local symbols, calling a visitor class V for each GOT offset
370 // associated with a local symbol.
371
372 template<int size, bool big_endian>
373 void
374 Sized_relobj<size, big_endian>::do_for_all_local_got_entries(
375     Got_offset_list::Visitor* v) const
376 {
377   unsigned int nsyms = this->local_symbol_count();
378   for (unsigned int i = 0; i < nsyms; i++)
379     {
380       Local_got_offsets::const_iterator p = this->local_got_offsets_.find(i);
381       if (p != this->local_got_offsets_.end())
382         {
383           const Got_offset_list* got_offsets = p->second;
384           got_offsets->for_all_got_offsets(v);
385         }
386     }
387 }
388
389 // Class Sized_relobj_file.
390
391 template<int size, bool big_endian>
392 Sized_relobj_file<size, big_endian>::Sized_relobj_file(
393     const std::string& name,
394     Input_file* input_file,
395     off_t offset,
396     const elfcpp::Ehdr<size, big_endian>& ehdr)
397   : Sized_relobj<size, big_endian>(name, input_file, offset),
398     elf_file_(this, ehdr),
399     symtab_shndx_(-1U),
400     local_symbol_count_(0),
401     output_local_symbol_count_(0),
402     output_local_dynsym_count_(0),
403     symbols_(),
404     defined_count_(0),
405     local_symbol_offset_(0),
406     local_dynsym_offset_(0),
407     local_values_(),
408     local_plt_offsets_(),
409     kept_comdat_sections_(),
410     has_eh_frame_(false),
411     discarded_eh_frame_shndx_(-1U),
412     deferred_layout_(),
413     deferred_layout_relocs_(),
414     compressed_sections_()
415 {
416   this->e_type_ = ehdr.get_e_type();
417 }
418
419 template<int size, bool big_endian>
420 Sized_relobj_file<size, big_endian>::~Sized_relobj_file()
421 {
422 }
423
424 // Set up an object file based on the file header.  This sets up the
425 // section information.
426
427 template<int size, bool big_endian>
428 void
429 Sized_relobj_file<size, big_endian>::do_setup()
430 {
431   const unsigned int shnum = this->elf_file_.shnum();
432   this->set_shnum(shnum);
433 }
434
435 // Find the SHT_SYMTAB section, given the section headers.  The ELF
436 // standard says that maybe in the future there can be more than one
437 // SHT_SYMTAB section.  Until somebody figures out how that could
438 // work, we assume there is only one.
439
440 template<int size, bool big_endian>
441 void
442 Sized_relobj_file<size, big_endian>::find_symtab(const unsigned char* pshdrs)
443 {
444   const unsigned int shnum = this->shnum();
445   this->symtab_shndx_ = 0;
446   if (shnum > 0)
447     {
448       // Look through the sections in reverse order, since gas tends
449       // to put the symbol table at the end.
450       const unsigned char* p = pshdrs + shnum * This::shdr_size;
451       unsigned int i = shnum;
452       unsigned int xindex_shndx = 0;
453       unsigned int xindex_link = 0;
454       while (i > 0)
455         {
456           --i;
457           p -= This::shdr_size;
458           typename This::Shdr shdr(p);
459           if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB)
460             {
461               this->symtab_shndx_ = i;
462               if (xindex_shndx > 0 && xindex_link == i)
463                 {
464                   Xindex* xindex =
465                     new Xindex(this->elf_file_.large_shndx_offset());
466                   xindex->read_symtab_xindex<size, big_endian>(this,
467                                                                xindex_shndx,
468                                                                pshdrs);
469                   this->set_xindex(xindex);
470                 }
471               break;
472             }
473
474           // Try to pick up the SHT_SYMTAB_SHNDX section, if there is
475           // one.  This will work if it follows the SHT_SYMTAB
476           // section.
477           if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX)
478             {
479               xindex_shndx = i;
480               xindex_link = this->adjust_shndx(shdr.get_sh_link());
481             }
482         }
483     }
484 }
485
486 // Return the Xindex structure to use for object with lots of
487 // sections.
488
489 template<int size, bool big_endian>
490 Xindex*
491 Sized_relobj_file<size, big_endian>::do_initialize_xindex()
492 {
493   gold_assert(this->symtab_shndx_ != -1U);
494   Xindex* xindex = new Xindex(this->elf_file_.large_shndx_offset());
495   xindex->initialize_symtab_xindex<size, big_endian>(this, this->symtab_shndx_);
496   return xindex;
497 }
498
499 // Return whether SHDR has the right type and flags to be a GNU
500 // .eh_frame section.
501
502 template<int size, bool big_endian>
503 bool
504 Sized_relobj_file<size, big_endian>::check_eh_frame_flags(
505     const elfcpp::Shdr<size, big_endian>* shdr) const
506 {
507   elfcpp::Elf_Word sh_type = shdr->get_sh_type();
508   return ((sh_type == elfcpp::SHT_PROGBITS
509            || sh_type == elfcpp::SHT_X86_64_UNWIND)
510           && (shdr->get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
511 }
512
513 // Find the section header with the given name.
514
515 template<int size, bool big_endian>
516 const unsigned char*
517 Sized_relobj_file<size, big_endian>::find_shdr(
518     const unsigned char* pshdrs,
519     const char* name,
520     const char* names,
521     section_size_type names_size,
522     const unsigned char* hdr) const
523 {
524   const unsigned int shnum = this->shnum();
525   const unsigned char* hdr_end = pshdrs + This::shdr_size * shnum;
526   size_t sh_name = 0;
527
528   while (1)
529     {
530       if (hdr)
531         {
532           // We found HDR last time we were called, continue looking.
533           typename This::Shdr shdr(hdr);
534           sh_name = shdr.get_sh_name();
535         }
536       else
537         {
538           // Look for the next occurrence of NAME in NAMES.
539           // The fact that .shstrtab produced by current GNU tools is
540           // string merged means we shouldn't have both .not.foo and
541           // .foo in .shstrtab, and multiple .foo sections should all
542           // have the same sh_name.  However, this is not guaranteed
543           // by the ELF spec and not all ELF object file producers may
544           // be so clever.
545           size_t len = strlen(name) + 1;
546           const char *p = sh_name ? names + sh_name + len : names;
547           p = reinterpret_cast<const char*>(memmem(p, names_size - (p - names),
548                                                    name, len));
549           if (p == NULL)
550             return NULL;
551           sh_name = p - names;
552           hdr = pshdrs;
553           if (sh_name == 0)
554             return hdr;
555         }
556
557       hdr += This::shdr_size;
558       while (hdr < hdr_end)
559         {
560           typename This::Shdr shdr(hdr);
561           if (shdr.get_sh_name() == sh_name)
562             return hdr;
563           hdr += This::shdr_size;
564         }
565       hdr = NULL;
566       if (sh_name == 0)
567         return hdr;
568     }
569 }
570
571 // Return whether there is a GNU .eh_frame section, given the section
572 // headers and the section names.
573
574 template<int size, bool big_endian>
575 bool
576 Sized_relobj_file<size, big_endian>::find_eh_frame(
577     const unsigned char* pshdrs,
578     const char* names,
579     section_size_type names_size) const
580 {
581   const unsigned char* s = NULL;
582
583   while (1)
584     {
585       s = this->find_shdr(pshdrs, ".eh_frame", names, names_size, s);
586       if (s == NULL)
587         return false;
588
589       typename This::Shdr shdr(s);
590       if (this->check_eh_frame_flags(&shdr))
591         return true;
592     }
593 }
594
595 // Return TRUE if this is a section whose contents will be needed in the
596 // Add_symbols task.  This function is only called for sections that have
597 // already passed the test in is_compressed_debug_section(), so we know
598 // that the section name begins with ".zdebug".
599
600 static bool
601 need_decompressed_section(const char* name)
602 {
603   // Skip over the ".zdebug" and a quick check for the "_".
604   name += 7;
605   if (*name++ != '_')
606     return false;
607
608 #ifdef ENABLE_THREADS
609   // Decompressing these sections now will help only if we're
610   // multithreaded.
611   if (parameters->options().threads())
612     {
613       // We will need .zdebug_str if this is not an incremental link
614       // (i.e., we are processing string merge sections) or if we need
615       // to build a gdb index.
616       if ((!parameters->incremental() || parameters->options().gdb_index())
617           && strcmp(name, "str") == 0)
618         return true;
619
620       // We will need these other sections when building a gdb index.
621       if (parameters->options().gdb_index()
622           && (strcmp(name, "info") == 0
623               || strcmp(name, "types") == 0
624               || strcmp(name, "pubnames") == 0
625               || strcmp(name, "pubtypes") == 0
626               || strcmp(name, "ranges") == 0
627               || strcmp(name, "abbrev") == 0))
628         return true;
629     }
630 #endif
631
632   // Even when single-threaded, we will need .zdebug_str if this is
633   // not an incremental link and we are building a gdb index.
634   // Otherwise, we would decompress the section twice: once for
635   // string merge processing, and once for building the gdb index.
636   if (!parameters->incremental()
637       && parameters->options().gdb_index()
638       && strcmp(name, "str") == 0)
639     return true;
640
641   return false;
642 }
643
644 // Build a table for any compressed debug sections, mapping each section index
645 // to the uncompressed size and (if needed) the decompressed contents.
646
647 template<int size, bool big_endian>
648 Compressed_section_map*
649 build_compressed_section_map(
650     const unsigned char* pshdrs,
651     unsigned int shnum,
652     const char* names,
653     section_size_type names_size,
654     Sized_relobj_file<size, big_endian>* obj)
655 {
656   Compressed_section_map* uncompressed_map = new Compressed_section_map();
657   const unsigned int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
658   const unsigned char* p = pshdrs + shdr_size;
659
660   for (unsigned int i = 1; i < shnum; ++i, p += shdr_size)
661     {
662       typename elfcpp::Shdr<size, big_endian> shdr(p);
663       if (shdr.get_sh_type() == elfcpp::SHT_PROGBITS
664           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
665         {
666           if (shdr.get_sh_name() >= names_size)
667             {
668               obj->error(_("bad section name offset for section %u: %lu"),
669                          i, static_cast<unsigned long>(shdr.get_sh_name()));
670               continue;
671             }
672
673           const char* name = names + shdr.get_sh_name();
674           if (is_compressed_debug_section(name))
675             {
676               section_size_type len;
677               const unsigned char* contents =
678                   obj->section_contents(i, &len, false);
679               uint64_t uncompressed_size = get_uncompressed_size(contents, len);
680               Compressed_section_info info;
681               info.size = convert_to_section_size_type(uncompressed_size);
682               info.contents = NULL;
683               if (uncompressed_size != -1ULL)
684                 {
685                   unsigned char* uncompressed_data = NULL;
686                   if (need_decompressed_section(name))
687                     {
688                       uncompressed_data = new unsigned char[uncompressed_size];
689                       if (decompress_input_section(contents, len,
690                                                    uncompressed_data,
691                                                    uncompressed_size))
692                         info.contents = uncompressed_data;
693                       else
694                         delete[] uncompressed_data;
695                     }
696                   (*uncompressed_map)[i] = info;
697                 }
698             }
699         }
700     }
701   return uncompressed_map;
702 }
703
704 // Stash away info for a number of special sections.
705 // Return true if any of the sections found require local symbols to be read.
706
707 template<int size, bool big_endian>
708 bool
709 Sized_relobj_file<size, big_endian>::do_find_special_sections(
710     Read_symbols_data* sd)
711 {
712   const unsigned char* const pshdrs = sd->section_headers->data();
713   const unsigned char* namesu = sd->section_names->data();
714   const char* names = reinterpret_cast<const char*>(namesu);
715
716   if (this->find_eh_frame(pshdrs, names, sd->section_names_size))
717     this->has_eh_frame_ = true;
718
719   if (memmem(names, sd->section_names_size, ".zdebug_", 8) != NULL)
720     this->compressed_sections_
721       = build_compressed_section_map(pshdrs, this->shnum(), names,
722                                      sd->section_names_size, this);
723   return (this->has_eh_frame_
724           || (!parameters->options().relocatable()
725               && parameters->options().gdb_index()
726               && (memmem(names, sd->section_names_size, "debug_info", 12) == 0
727                   || memmem(names, sd->section_names_size, "debug_types",
728                             13) == 0)));
729 }
730
731 // Read the sections and symbols from an object file.
732
733 template<int size, bool big_endian>
734 void
735 Sized_relobj_file<size, big_endian>::do_read_symbols(Read_symbols_data* sd)
736 {
737   this->read_section_data(&this->elf_file_, sd);
738
739   const unsigned char* const pshdrs = sd->section_headers->data();
740
741   this->find_symtab(pshdrs);
742
743   bool need_local_symbols = this->do_find_special_sections(sd);
744
745   sd->symbols = NULL;
746   sd->symbols_size = 0;
747   sd->external_symbols_offset = 0;
748   sd->symbol_names = NULL;
749   sd->symbol_names_size = 0;
750
751   if (this->symtab_shndx_ == 0)
752     {
753       // No symbol table.  Weird but legal.
754       return;
755     }
756
757   // Get the symbol table section header.
758   typename This::Shdr symtabshdr(pshdrs
759                                  + this->symtab_shndx_ * This::shdr_size);
760   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
761
762   // If this object has a .eh_frame section, or if building a .gdb_index
763   // section and there is debug info, we need all the symbols.
764   // Otherwise we only need the external symbols.  While it would be
765   // simpler to just always read all the symbols, I've seen object
766   // files with well over 2000 local symbols, which for a 64-bit
767   // object file format is over 5 pages that we don't need to read
768   // now.
769
770   const int sym_size = This::sym_size;
771   const unsigned int loccount = symtabshdr.get_sh_info();
772   this->local_symbol_count_ = loccount;
773   this->local_values_.resize(loccount);
774   section_offset_type locsize = loccount * sym_size;
775   off_t dataoff = symtabshdr.get_sh_offset();
776   section_size_type datasize =
777     convert_to_section_size_type(symtabshdr.get_sh_size());
778   off_t extoff = dataoff + locsize;
779   section_size_type extsize = datasize - locsize;
780
781   off_t readoff = need_local_symbols ? dataoff : extoff;
782   section_size_type readsize = need_local_symbols ? datasize : extsize;
783
784   if (readsize == 0)
785     {
786       // No external symbols.  Also weird but also legal.
787       return;
788     }
789
790   File_view* fvsymtab = this->get_lasting_view(readoff, readsize, true, false);
791
792   // Read the section header for the symbol names.
793   unsigned int strtab_shndx = this->adjust_shndx(symtabshdr.get_sh_link());
794   if (strtab_shndx >= this->shnum())
795     {
796       this->error(_("invalid symbol table name index: %u"), strtab_shndx);
797       return;
798     }
799   typename This::Shdr strtabshdr(pshdrs + strtab_shndx * This::shdr_size);
800   if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB)
801     {
802       this->error(_("symbol table name section has wrong type: %u"),
803                   static_cast<unsigned int>(strtabshdr.get_sh_type()));
804       return;
805     }
806
807   // Read the symbol names.
808   File_view* fvstrtab = this->get_lasting_view(strtabshdr.get_sh_offset(),
809                                                strtabshdr.get_sh_size(),
810                                                false, true);
811
812   sd->symbols = fvsymtab;
813   sd->symbols_size = readsize;
814   sd->external_symbols_offset = need_local_symbols ? locsize : 0;
815   sd->symbol_names = fvstrtab;
816   sd->symbol_names_size =
817     convert_to_section_size_type(strtabshdr.get_sh_size());
818 }
819
820 // Return the section index of symbol SYM.  Set *VALUE to its value in
821 // the object file.  Set *IS_ORDINARY if this is an ordinary section
822 // index, not a special code between SHN_LORESERVE and SHN_HIRESERVE.
823 // Note that for a symbol which is not defined in this object file,
824 // this will set *VALUE to 0 and return SHN_UNDEF; it will not return
825 // the final value of the symbol in the link.
826
827 template<int size, bool big_endian>
828 unsigned int
829 Sized_relobj_file<size, big_endian>::symbol_section_and_value(unsigned int sym,
830                                                               Address* value,
831                                                               bool* is_ordinary)
832 {
833   section_size_type symbols_size;
834   const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
835                                                         &symbols_size,
836                                                         false);
837
838   const size_t count = symbols_size / This::sym_size;
839   gold_assert(sym < count);
840
841   elfcpp::Sym<size, big_endian> elfsym(symbols + sym * This::sym_size);
842   *value = elfsym.get_st_value();
843
844   return this->adjust_sym_shndx(sym, elfsym.get_st_shndx(), is_ordinary);
845 }
846
847 // Return whether to include a section group in the link.  LAYOUT is
848 // used to keep track of which section groups we have already seen.
849 // INDEX is the index of the section group and SHDR is the section
850 // header.  If we do not want to include this group, we set bits in
851 // OMIT for each section which should be discarded.
852
853 template<int size, bool big_endian>
854 bool
855 Sized_relobj_file<size, big_endian>::include_section_group(
856     Symbol_table* symtab,
857     Layout* layout,
858     unsigned int index,
859     const char* name,
860     const unsigned char* shdrs,
861     const char* section_names,
862     section_size_type section_names_size,
863     std::vector<bool>* omit)
864 {
865   // Read the section contents.
866   typename This::Shdr shdr(shdrs + index * This::shdr_size);
867   const unsigned char* pcon = this->get_view(shdr.get_sh_offset(),
868                                              shdr.get_sh_size(), true, false);
869   const elfcpp::Elf_Word* pword =
870     reinterpret_cast<const elfcpp::Elf_Word*>(pcon);
871
872   // The first word contains flags.  We only care about COMDAT section
873   // groups.  Other section groups are always included in the link
874   // just like ordinary sections.
875   elfcpp::Elf_Word flags = elfcpp::Swap<32, big_endian>::readval(pword);
876
877   // Look up the group signature, which is the name of a symbol.  ELF
878   // uses a symbol name because some group signatures are long, and
879   // the name is generally already in the symbol table, so it makes
880   // sense to put the long string just once in .strtab rather than in
881   // both .strtab and .shstrtab.
882
883   // Get the appropriate symbol table header (this will normally be
884   // the single SHT_SYMTAB section, but in principle it need not be).
885   const unsigned int link = this->adjust_shndx(shdr.get_sh_link());
886   typename This::Shdr symshdr(this, this->elf_file_.section_header(link));
887
888   // Read the symbol table entry.
889   unsigned int symndx = shdr.get_sh_info();
890   if (symndx >= symshdr.get_sh_size() / This::sym_size)
891     {
892       this->error(_("section group %u info %u out of range"),
893                   index, symndx);
894       return false;
895     }
896   off_t symoff = symshdr.get_sh_offset() + symndx * This::sym_size;
897   const unsigned char* psym = this->get_view(symoff, This::sym_size, true,
898                                              false);
899   elfcpp::Sym<size, big_endian> sym(psym);
900
901   // Read the symbol table names.
902   section_size_type symnamelen;
903   const unsigned char* psymnamesu;
904   psymnamesu = this->section_contents(this->adjust_shndx(symshdr.get_sh_link()),
905                                       &symnamelen, true);
906   const char* psymnames = reinterpret_cast<const char*>(psymnamesu);
907
908   // Get the section group signature.
909   if (sym.get_st_name() >= symnamelen)
910     {
911       this->error(_("symbol %u name offset %u out of range"),
912                   symndx, sym.get_st_name());
913       return false;
914     }
915
916   std::string signature(psymnames + sym.get_st_name());
917
918   // It seems that some versions of gas will create a section group
919   // associated with a section symbol, and then fail to give a name to
920   // the section symbol.  In such a case, use the name of the section.
921   if (signature[0] == '\0' && sym.get_st_type() == elfcpp::STT_SECTION)
922     {
923       bool is_ordinary;
924       unsigned int sym_shndx = this->adjust_sym_shndx(symndx,
925                                                       sym.get_st_shndx(),
926                                                       &is_ordinary);
927       if (!is_ordinary || sym_shndx >= this->shnum())
928         {
929           this->error(_("symbol %u invalid section index %u"),
930                       symndx, sym_shndx);
931           return false;
932         }
933       typename This::Shdr member_shdr(shdrs + sym_shndx * This::shdr_size);
934       if (member_shdr.get_sh_name() < section_names_size)
935         signature = section_names + member_shdr.get_sh_name();
936     }
937
938   // Record this section group in the layout, and see whether we've already
939   // seen one with the same signature.
940   bool include_group;
941   bool is_comdat;
942   Kept_section* kept_section = NULL;
943
944   if ((flags & elfcpp::GRP_COMDAT) == 0)
945     {
946       include_group = true;
947       is_comdat = false;
948     }
949   else
950     {
951       include_group = layout->find_or_add_kept_section(signature,
952                                                        this, index, true,
953                                                        true, &kept_section);
954       is_comdat = true;
955     }
956
957   if (is_comdat && include_group)
958     {
959       Incremental_inputs* incremental_inputs = layout->incremental_inputs();
960       if (incremental_inputs != NULL)
961         incremental_inputs->report_comdat_group(this, signature.c_str());
962     }
963
964   size_t count = shdr.get_sh_size() / sizeof(elfcpp::Elf_Word);
965
966   std::vector<unsigned int> shndxes;
967   bool relocate_group = include_group && parameters->options().relocatable();
968   if (relocate_group)
969     shndxes.reserve(count - 1);
970
971   for (size_t i = 1; i < count; ++i)
972     {
973       elfcpp::Elf_Word shndx =
974         this->adjust_shndx(elfcpp::Swap<32, big_endian>::readval(pword + i));
975
976       if (relocate_group)
977         shndxes.push_back(shndx);
978
979       if (shndx >= this->shnum())
980         {
981           this->error(_("section %u in section group %u out of range"),
982                       shndx, index);
983           continue;
984         }
985
986       // Check for an earlier section number, since we're going to get
987       // it wrong--we may have already decided to include the section.
988       if (shndx < index)
989         this->error(_("invalid section group %u refers to earlier section %u"),
990                     index, shndx);
991
992       // Get the name of the member section.
993       typename This::Shdr member_shdr(shdrs + shndx * This::shdr_size);
994       if (member_shdr.get_sh_name() >= section_names_size)
995         {
996           // This is an error, but it will be diagnosed eventually
997           // in do_layout, so we don't need to do anything here but
998           // ignore it.
999           continue;
1000         }
1001       std::string mname(section_names + member_shdr.get_sh_name());
1002
1003       if (include_group)
1004         {
1005           if (is_comdat)
1006             kept_section->add_comdat_section(mname, shndx,
1007                                              member_shdr.get_sh_size());
1008         }
1009       else
1010         {
1011           (*omit)[shndx] = true;
1012
1013           if (is_comdat)
1014             {
1015               Relobj* kept_object = kept_section->object();
1016               if (kept_section->is_comdat())
1017                 {
1018                   // Find the corresponding kept section, and store
1019                   // that info in the discarded section table.
1020                   unsigned int kept_shndx;
1021                   uint64_t kept_size;
1022                   if (kept_section->find_comdat_section(mname, &kept_shndx,
1023                                                         &kept_size))
1024                     {
1025                       // We don't keep a mapping for this section if
1026                       // it has a different size.  The mapping is only
1027                       // used for relocation processing, and we don't
1028                       // want to treat the sections as similar if the
1029                       // sizes are different.  Checking the section
1030                       // size is the approach used by the GNU linker.
1031                       if (kept_size == member_shdr.get_sh_size())
1032                         this->set_kept_comdat_section(shndx, kept_object,
1033                                                       kept_shndx);
1034                     }
1035                 }
1036               else
1037                 {
1038                   // The existing section is a linkonce section.  Add
1039                   // a mapping if there is exactly one section in the
1040                   // group (which is true when COUNT == 2) and if it
1041                   // is the same size.
1042                   if (count == 2
1043                       && (kept_section->linkonce_size()
1044                           == member_shdr.get_sh_size()))
1045                     this->set_kept_comdat_section(shndx, kept_object,
1046                                                   kept_section->shndx());
1047                 }
1048             }
1049         }
1050     }
1051
1052   if (relocate_group)
1053     layout->layout_group(symtab, this, index, name, signature.c_str(),
1054                          shdr, flags, &shndxes);
1055
1056   return include_group;
1057 }
1058
1059 // Whether to include a linkonce section in the link.  NAME is the
1060 // name of the section and SHDR is the section header.
1061
1062 // Linkonce sections are a GNU extension implemented in the original
1063 // GNU linker before section groups were defined.  The semantics are
1064 // that we only include one linkonce section with a given name.  The
1065 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
1066 // where T is the type of section and SYMNAME is the name of a symbol.
1067 // In an attempt to make linkonce sections interact well with section
1068 // groups, we try to identify SYMNAME and use it like a section group
1069 // signature.  We want to block section groups with that signature,
1070 // but not other linkonce sections with that signature.  We also use
1071 // the full name of the linkonce section as a normal section group
1072 // signature.
1073
1074 template<int size, bool big_endian>
1075 bool
1076 Sized_relobj_file<size, big_endian>::include_linkonce_section(
1077     Layout* layout,
1078     unsigned int index,
1079     const char* name,
1080     const elfcpp::Shdr<size, big_endian>& shdr)
1081 {
1082   typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
1083   // In general the symbol name we want will be the string following
1084   // the last '.'.  However, we have to handle the case of
1085   // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
1086   // some versions of gcc.  So we use a heuristic: if the name starts
1087   // with ".gnu.linkonce.t.", we use everything after that.  Otherwise
1088   // we look for the last '.'.  We can't always simply skip
1089   // ".gnu.linkonce.X", because we have to deal with cases like
1090   // ".gnu.linkonce.d.rel.ro.local".
1091   const char* const linkonce_t = ".gnu.linkonce.t.";
1092   const char* symname;
1093   if (strncmp(name, linkonce_t, strlen(linkonce_t)) == 0)
1094     symname = name + strlen(linkonce_t);
1095   else
1096     symname = strrchr(name, '.') + 1;
1097   std::string sig1(symname);
1098   std::string sig2(name);
1099   Kept_section* kept1;
1100   Kept_section* kept2;
1101   bool include1 = layout->find_or_add_kept_section(sig1, this, index, false,
1102                                                    false, &kept1);
1103   bool include2 = layout->find_or_add_kept_section(sig2, this, index, false,
1104                                                    true, &kept2);
1105
1106   if (!include2)
1107     {
1108       // We are not including this section because we already saw the
1109       // name of the section as a signature.  This normally implies
1110       // that the kept section is another linkonce section.  If it is
1111       // the same size, record it as the section which corresponds to
1112       // this one.
1113       if (kept2->object() != NULL
1114           && !kept2->is_comdat()
1115           && kept2->linkonce_size() == sh_size)
1116         this->set_kept_comdat_section(index, kept2->object(), kept2->shndx());
1117     }
1118   else if (!include1)
1119     {
1120       // The section is being discarded on the basis of its symbol
1121       // name.  This means that the corresponding kept section was
1122       // part of a comdat group, and it will be difficult to identify
1123       // the specific section within that group that corresponds to
1124       // this linkonce section.  We'll handle the simple case where
1125       // the group has only one member section.  Otherwise, it's not
1126       // worth the effort.
1127       unsigned int kept_shndx;
1128       uint64_t kept_size;
1129       if (kept1->object() != NULL
1130           && kept1->is_comdat()
1131           && kept1->find_single_comdat_section(&kept_shndx, &kept_size)
1132           && kept_size == sh_size)
1133         this->set_kept_comdat_section(index, kept1->object(), kept_shndx);
1134     }
1135   else
1136     {
1137       kept1->set_linkonce_size(sh_size);
1138       kept2->set_linkonce_size(sh_size);
1139     }
1140
1141   return include1 && include2;
1142 }
1143
1144 // Layout an input section.
1145
1146 template<int size, bool big_endian>
1147 inline void
1148 Sized_relobj_file<size, big_endian>::layout_section(
1149     Layout* layout,
1150     unsigned int shndx,
1151     const char* name,
1152     const typename This::Shdr& shdr,
1153     unsigned int reloc_shndx,
1154     unsigned int reloc_type)
1155 {
1156   off_t offset;
1157   Output_section* os = layout->layout(this, shndx, name, shdr,
1158                                           reloc_shndx, reloc_type, &offset);
1159
1160   this->output_sections()[shndx] = os;
1161   if (offset == -1)
1162     this->section_offsets()[shndx] = invalid_address;
1163   else
1164     this->section_offsets()[shndx] = convert_types<Address, off_t>(offset);
1165
1166   // If this section requires special handling, and if there are
1167   // relocs that apply to it, then we must do the special handling
1168   // before we apply the relocs.
1169   if (offset == -1 && reloc_shndx != 0)
1170     this->set_relocs_must_follow_section_writes();
1171 }
1172
1173 // Layout an input .eh_frame section.
1174
1175 template<int size, bool big_endian>
1176 void
1177 Sized_relobj_file<size, big_endian>::layout_eh_frame_section(
1178     Layout* layout,
1179     const unsigned char* symbols_data,
1180     section_size_type symbols_size,
1181     const unsigned char* symbol_names_data,
1182     section_size_type symbol_names_size,
1183     unsigned int shndx,
1184     const typename This::Shdr& shdr,
1185     unsigned int reloc_shndx,
1186     unsigned int reloc_type)
1187 {
1188   gold_assert(this->has_eh_frame_);
1189
1190   off_t offset;
1191   Output_section* os = layout->layout_eh_frame(this,
1192                                                symbols_data,
1193                                                symbols_size,
1194                                                symbol_names_data,
1195                                                symbol_names_size,
1196                                                shndx,
1197                                                shdr,
1198                                                reloc_shndx,
1199                                                reloc_type,
1200                                                &offset);
1201   this->output_sections()[shndx] = os;
1202   if (os == NULL || offset == -1)
1203     {
1204       // An object can contain at most one section holding exception
1205       // frame information.
1206       gold_assert(this->discarded_eh_frame_shndx_ == -1U);
1207       this->discarded_eh_frame_shndx_ = shndx;
1208       this->section_offsets()[shndx] = invalid_address;
1209     }
1210   else
1211     this->section_offsets()[shndx] = convert_types<Address, off_t>(offset);
1212
1213   // If this section requires special handling, and if there are
1214   // relocs that aply to it, then we must do the special handling
1215   // before we apply the relocs.
1216   if (os != NULL && offset == -1 && reloc_shndx != 0)
1217     this->set_relocs_must_follow_section_writes();
1218 }
1219
1220 // Lay out the input sections.  We walk through the sections and check
1221 // whether they should be included in the link.  If they should, we
1222 // pass them to the Layout object, which will return an output section
1223 // and an offset.
1224 // During garbage collection (--gc-sections) and identical code folding
1225 // (--icf), this function is called twice.  When it is called the first
1226 // time, it is for setting up some sections as roots to a work-list for
1227 // --gc-sections and to do comdat processing.  Actual layout happens the
1228 // second time around after all the relevant sections have been determined.
1229 // The first time, is_worklist_ready or is_icf_ready is false. It is then
1230 // set to true after the garbage collection worklist or identical code
1231 // folding is processed and the relevant sections to be kept are
1232 // determined.  Then, this function is called again to layout the sections.
1233
1234 template<int size, bool big_endian>
1235 void
1236 Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
1237                                                Layout* layout,
1238                                                Read_symbols_data* sd)
1239 {
1240   const unsigned int shnum = this->shnum();
1241   bool is_gc_pass_one = ((parameters->options().gc_sections()
1242                           && !symtab->gc()->is_worklist_ready())
1243                          || (parameters->options().icf_enabled()
1244                              && !symtab->icf()->is_icf_ready()));
1245
1246   bool is_gc_pass_two = ((parameters->options().gc_sections()
1247                           && symtab->gc()->is_worklist_ready())
1248                          || (parameters->options().icf_enabled()
1249                              && symtab->icf()->is_icf_ready()));
1250
1251   bool is_gc_or_icf = (parameters->options().gc_sections()
1252                        || parameters->options().icf_enabled());
1253
1254   // Both is_gc_pass_one and is_gc_pass_two should not be true.
1255   gold_assert(!(is_gc_pass_one  && is_gc_pass_two));
1256
1257   if (shnum == 0)
1258     return;
1259   Symbols_data* gc_sd = NULL;
1260   if (is_gc_pass_one)
1261     {
1262       // During garbage collection save the symbols data to use it when
1263       // re-entering this function.
1264       gc_sd = new Symbols_data;
1265       this->copy_symbols_data(gc_sd, sd, This::shdr_size * shnum);
1266       this->set_symbols_data(gc_sd);
1267     }
1268   else if (is_gc_pass_two)
1269     {
1270       gc_sd = this->get_symbols_data();
1271     }
1272
1273   const unsigned char* section_headers_data = NULL;
1274   section_size_type section_names_size;
1275   const unsigned char* symbols_data = NULL;
1276   section_size_type symbols_size;
1277   const unsigned char* symbol_names_data = NULL;
1278   section_size_type symbol_names_size;
1279
1280   if (is_gc_or_icf)
1281     {
1282       section_headers_data = gc_sd->section_headers_data;
1283       section_names_size = gc_sd->section_names_size;
1284       symbols_data = gc_sd->symbols_data;
1285       symbols_size = gc_sd->symbols_size;
1286       symbol_names_data = gc_sd->symbol_names_data;
1287       symbol_names_size = gc_sd->symbol_names_size;
1288     }
1289   else
1290     {
1291       section_headers_data = sd->section_headers->data();
1292       section_names_size = sd->section_names_size;
1293       if (sd->symbols != NULL)
1294         symbols_data = sd->symbols->data();
1295       symbols_size = sd->symbols_size;
1296       if (sd->symbol_names != NULL)
1297         symbol_names_data = sd->symbol_names->data();
1298       symbol_names_size = sd->symbol_names_size;
1299     }
1300
1301   // Get the section headers.
1302   const unsigned char* shdrs = section_headers_data;
1303   const unsigned char* pshdrs;
1304
1305   // Get the section names.
1306   const unsigned char* pnamesu = (is_gc_or_icf)
1307                                  ? gc_sd->section_names_data
1308                                  : sd->section_names->data();
1309
1310   const char* pnames = reinterpret_cast<const char*>(pnamesu);
1311
1312   // If any input files have been claimed by plugins, we need to defer
1313   // actual layout until the replacement files have arrived.
1314   const bool should_defer_layout =
1315       (parameters->options().has_plugins()
1316        && parameters->options().plugins()->should_defer_layout());
1317   unsigned int num_sections_to_defer = 0;
1318
1319   // For each section, record the index of the reloc section if any.
1320   // Use 0 to mean that there is no reloc section, -1U to mean that
1321   // there is more than one.
1322   std::vector<unsigned int> reloc_shndx(shnum, 0);
1323   std::vector<unsigned int> reloc_type(shnum, elfcpp::SHT_NULL);
1324   // Skip the first, dummy, section.
1325   pshdrs = shdrs + This::shdr_size;
1326   for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1327     {
1328       typename This::Shdr shdr(pshdrs);
1329
1330       // Count the number of sections whose layout will be deferred.
1331       if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1332         ++num_sections_to_defer;
1333
1334       unsigned int sh_type = shdr.get_sh_type();
1335       if (sh_type == elfcpp::SHT_REL || sh_type == elfcpp::SHT_RELA)
1336         {
1337           unsigned int target_shndx = this->adjust_shndx(shdr.get_sh_info());
1338           if (target_shndx == 0 || target_shndx >= shnum)
1339             {
1340               this->error(_("relocation section %u has bad info %u"),
1341                           i, target_shndx);
1342               continue;
1343             }
1344
1345           if (reloc_shndx[target_shndx] != 0)
1346             reloc_shndx[target_shndx] = -1U;
1347           else
1348             {
1349               reloc_shndx[target_shndx] = i;
1350               reloc_type[target_shndx] = sh_type;
1351             }
1352         }
1353     }
1354
1355   Output_sections& out_sections(this->output_sections());
1356   std::vector<Address>& out_section_offsets(this->section_offsets());
1357
1358   if (!is_gc_pass_two)
1359     {
1360       out_sections.resize(shnum);
1361       out_section_offsets.resize(shnum);
1362     }
1363
1364   // If we are only linking for symbols, then there is nothing else to
1365   // do here.
1366   if (this->input_file()->just_symbols())
1367     {
1368       if (!is_gc_pass_two)
1369         {
1370           delete sd->section_headers;
1371           sd->section_headers = NULL;
1372           delete sd->section_names;
1373           sd->section_names = NULL;
1374         }
1375       return;
1376     }
1377
1378   if (num_sections_to_defer > 0)
1379     {
1380       parameters->options().plugins()->add_deferred_layout_object(this);
1381       this->deferred_layout_.reserve(num_sections_to_defer);
1382     }
1383
1384   // Whether we've seen a .note.GNU-stack section.
1385   bool seen_gnu_stack = false;
1386   // The flags of a .note.GNU-stack section.
1387   uint64_t gnu_stack_flags = 0;
1388
1389   // Keep track of which sections to omit.
1390   std::vector<bool> omit(shnum, false);
1391
1392   // Keep track of reloc sections when emitting relocations.
1393   const bool relocatable = parameters->options().relocatable();
1394   const bool emit_relocs = (relocatable
1395                             || parameters->options().emit_relocs());
1396   std::vector<unsigned int> reloc_sections;
1397
1398   // Keep track of .eh_frame sections.
1399   std::vector<unsigned int> eh_frame_sections;
1400
1401   // Keep track of .debug_info and .debug_types sections.
1402   std::vector<unsigned int> debug_info_sections;
1403   std::vector<unsigned int> debug_types_sections;
1404
1405   // Skip the first, dummy, section.
1406   pshdrs = shdrs + This::shdr_size;
1407   for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1408     {
1409       typename This::Shdr shdr(pshdrs);
1410
1411       if (shdr.get_sh_name() >= section_names_size)
1412         {
1413           this->error(_("bad section name offset for section %u: %lu"),
1414                       i, static_cast<unsigned long>(shdr.get_sh_name()));
1415           return;
1416         }
1417
1418       const char* name = pnames + shdr.get_sh_name();
1419
1420       if (!is_gc_pass_two)
1421         {
1422           if (this->handle_gnu_warning_section(name, i, symtab))
1423             {
1424               if (!relocatable && !parameters->options().shared())
1425                 omit[i] = true;
1426             }
1427
1428           // The .note.GNU-stack section is special.  It gives the
1429           // protection flags that this object file requires for the stack
1430           // in memory.
1431           if (strcmp(name, ".note.GNU-stack") == 0)
1432             {
1433               seen_gnu_stack = true;
1434               gnu_stack_flags |= shdr.get_sh_flags();
1435               omit[i] = true;
1436             }
1437
1438           // The .note.GNU-split-stack section is also special.  It
1439           // indicates that the object was compiled with
1440           // -fsplit-stack.
1441           if (this->handle_split_stack_section(name))
1442             {
1443               if (!relocatable && !parameters->options().shared())
1444                 omit[i] = true;
1445             }
1446
1447           // Skip attributes section.
1448           if (parameters->target().is_attributes_section(name))
1449             {
1450               omit[i] = true;
1451             }
1452
1453           bool discard = omit[i];
1454           if (!discard)
1455             {
1456               if (shdr.get_sh_type() == elfcpp::SHT_GROUP)
1457                 {
1458                   if (!this->include_section_group(symtab, layout, i, name,
1459                                                    shdrs, pnames,
1460                                                    section_names_size,
1461                                                    &omit))
1462                     discard = true;
1463                 }
1464               else if ((shdr.get_sh_flags() & elfcpp::SHF_GROUP) == 0
1465                        && Layout::is_linkonce(name))
1466                 {
1467                   if (!this->include_linkonce_section(layout, i, name, shdr))
1468                     discard = true;
1469                 }
1470             }
1471
1472           // Add the section to the incremental inputs layout.
1473           Incremental_inputs* incremental_inputs = layout->incremental_inputs();
1474           if (incremental_inputs != NULL
1475               && !discard
1476               && can_incremental_update(shdr.get_sh_type()))
1477             {
1478               off_t sh_size = shdr.get_sh_size();
1479               section_size_type uncompressed_size;
1480               if (this->section_is_compressed(i, &uncompressed_size))
1481                 sh_size = uncompressed_size;
1482               incremental_inputs->report_input_section(this, i, name, sh_size);
1483             }
1484
1485           if (discard)
1486             {
1487               // Do not include this section in the link.
1488               out_sections[i] = NULL;
1489               out_section_offsets[i] = invalid_address;
1490               continue;
1491             }
1492         }
1493
1494       if (is_gc_pass_one && parameters->options().gc_sections())
1495         {
1496           if (this->is_section_name_included(name)
1497               || layout->keep_input_section (this, name)
1498               || shdr.get_sh_type() == elfcpp::SHT_INIT_ARRAY
1499               || shdr.get_sh_type() == elfcpp::SHT_FINI_ARRAY)
1500             {
1501               symtab->gc()->worklist().push(Section_id(this, i));
1502             }
1503           // If the section name XXX can be represented as a C identifier
1504           // it cannot be discarded if there are references to
1505           // __start_XXX and __stop_XXX symbols.  These need to be
1506           // specially handled.
1507           if (is_cident(name))
1508             {
1509               symtab->gc()->add_cident_section(name, Section_id(this, i));
1510             }
1511         }
1512
1513       // When doing a relocatable link we are going to copy input
1514       // reloc sections into the output.  We only want to copy the
1515       // ones associated with sections which are not being discarded.
1516       // However, we don't know that yet for all sections.  So save
1517       // reloc sections and process them later. Garbage collection is
1518       // not triggered when relocatable code is desired.
1519       if (emit_relocs
1520           && (shdr.get_sh_type() == elfcpp::SHT_REL
1521               || shdr.get_sh_type() == elfcpp::SHT_RELA))
1522         {
1523           reloc_sections.push_back(i);
1524           continue;
1525         }
1526
1527       if (relocatable && shdr.get_sh_type() == elfcpp::SHT_GROUP)
1528         continue;
1529
1530       // The .eh_frame section is special.  It holds exception frame
1531       // information that we need to read in order to generate the
1532       // exception frame header.  We process these after all the other
1533       // sections so that the exception frame reader can reliably
1534       // determine which sections are being discarded, and discard the
1535       // corresponding information.
1536       if (!relocatable
1537           && strcmp(name, ".eh_frame") == 0
1538           && this->check_eh_frame_flags(&shdr))
1539         {
1540           if (is_gc_pass_one)
1541             {
1542               out_sections[i] = reinterpret_cast<Output_section*>(1);
1543               out_section_offsets[i] = invalid_address;
1544             }
1545           else if (should_defer_layout)
1546             this->deferred_layout_.push_back(Deferred_layout(i, name,
1547                                                              pshdrs,
1548                                                              reloc_shndx[i],
1549                                                              reloc_type[i]));
1550           else
1551             eh_frame_sections.push_back(i);
1552           continue;
1553         }
1554
1555       if (is_gc_pass_two && parameters->options().gc_sections())
1556         {
1557           // This is executed during the second pass of garbage
1558           // collection. do_layout has been called before and some
1559           // sections have been already discarded. Simply ignore
1560           // such sections this time around.
1561           if (out_sections[i] == NULL)
1562             {
1563               gold_assert(out_section_offsets[i] == invalid_address);
1564               continue;
1565             }
1566           if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1567               && symtab->gc()->is_section_garbage(this, i))
1568               {
1569                 if (parameters->options().print_gc_sections())
1570                   gold_info(_("%s: removing unused section from '%s'"
1571                               " in file '%s'"),
1572                             program_name, this->section_name(i).c_str(),
1573                             this->name().c_str());
1574                 out_sections[i] = NULL;
1575                 out_section_offsets[i] = invalid_address;
1576                 continue;
1577               }
1578         }
1579
1580       if (is_gc_pass_two && parameters->options().icf_enabled())
1581         {
1582           if (out_sections[i] == NULL)
1583             {
1584               gold_assert(out_section_offsets[i] == invalid_address);
1585               continue;
1586             }
1587           if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1588               && symtab->icf()->is_section_folded(this, i))
1589               {
1590                 if (parameters->options().print_icf_sections())
1591                   {
1592                     Section_id folded =
1593                                 symtab->icf()->get_folded_section(this, i);
1594                     Relobj* folded_obj =
1595                                 reinterpret_cast<Relobj*>(folded.first);
1596                     gold_info(_("%s: ICF folding section '%s' in file '%s'"
1597                                 "into '%s' in file '%s'"),
1598                               program_name, this->section_name(i).c_str(),
1599                               this->name().c_str(),
1600                               folded_obj->section_name(folded.second).c_str(),
1601                               folded_obj->name().c_str());
1602                   }
1603                 out_sections[i] = NULL;
1604                 out_section_offsets[i] = invalid_address;
1605                 continue;
1606               }
1607         }
1608
1609       // Defer layout here if input files are claimed by plugins.  When gc
1610       // is turned on this function is called twice.  For the second call
1611       // should_defer_layout should be false.
1612       if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1613         {
1614           gold_assert(!is_gc_pass_two);
1615           this->deferred_layout_.push_back(Deferred_layout(i, name,
1616                                                            pshdrs,
1617                                                            reloc_shndx[i],
1618                                                            reloc_type[i]));
1619           // Put dummy values here; real values will be supplied by
1620           // do_layout_deferred_sections.
1621           out_sections[i] = reinterpret_cast<Output_section*>(2);
1622           out_section_offsets[i] = invalid_address;
1623           continue;
1624         }
1625
1626       // During gc_pass_two if a section that was previously deferred is
1627       // found, do not layout the section as layout_deferred_sections will
1628       // do it later from gold.cc.
1629       if (is_gc_pass_two
1630           && (out_sections[i] == reinterpret_cast<Output_section*>(2)))
1631         continue;
1632
1633       if (is_gc_pass_one)
1634         {
1635           // This is during garbage collection. The out_sections are
1636           // assigned in the second call to this function.
1637           out_sections[i] = reinterpret_cast<Output_section*>(1);
1638           out_section_offsets[i] = invalid_address;
1639         }
1640       else
1641         {
1642           // When garbage collection is switched on the actual layout
1643           // only happens in the second call.
1644           this->layout_section(layout, i, name, shdr, reloc_shndx[i],
1645                                reloc_type[i]);
1646
1647           // When generating a .gdb_index section, we do additional
1648           // processing of .debug_info and .debug_types sections after all
1649           // the other sections for the same reason as above.
1650           if (!relocatable
1651               && parameters->options().gdb_index()
1652               && !(shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1653             {
1654               if (strcmp(name, ".debug_info") == 0
1655                   || strcmp(name, ".zdebug_info") == 0)
1656                 debug_info_sections.push_back(i);
1657               else if (strcmp(name, ".debug_types") == 0
1658                        || strcmp(name, ".zdebug_types") == 0)
1659                 debug_types_sections.push_back(i);
1660             }
1661         }
1662     }
1663
1664   if (!is_gc_pass_two)
1665     layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags, this);
1666
1667   // When doing a relocatable link handle the reloc sections at the
1668   // end.  Garbage collection  and Identical Code Folding is not
1669   // turned on for relocatable code.
1670   if (emit_relocs)
1671     this->size_relocatable_relocs();
1672
1673   gold_assert(!(is_gc_or_icf) || reloc_sections.empty());
1674
1675   for (std::vector<unsigned int>::const_iterator p = reloc_sections.begin();
1676        p != reloc_sections.end();
1677        ++p)
1678     {
1679       unsigned int i = *p;
1680       const unsigned char* pshdr;
1681       pshdr = section_headers_data + i * This::shdr_size;
1682       typename This::Shdr shdr(pshdr);
1683
1684       unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1685       if (data_shndx >= shnum)
1686         {
1687           // We already warned about this above.
1688           continue;
1689         }
1690
1691       Output_section* data_section = out_sections[data_shndx];
1692       if (data_section == reinterpret_cast<Output_section*>(2))
1693         {
1694           // The layout for the data section was deferred, so we need
1695           // to defer the relocation section, too.
1696           const char* name = pnames + shdr.get_sh_name();
1697           this->deferred_layout_relocs_.push_back(
1698               Deferred_layout(i, name, pshdr, 0, elfcpp::SHT_NULL));
1699           out_sections[i] = reinterpret_cast<Output_section*>(2);
1700           out_section_offsets[i] = invalid_address;
1701           continue;
1702         }
1703       if (data_section == NULL)
1704         {
1705           out_sections[i] = NULL;
1706           out_section_offsets[i] = invalid_address;
1707           continue;
1708         }
1709
1710       Relocatable_relocs* rr = new Relocatable_relocs();
1711       this->set_relocatable_relocs(i, rr);
1712
1713       Output_section* os = layout->layout_reloc(this, i, shdr, data_section,
1714                                                 rr);
1715       out_sections[i] = os;
1716       out_section_offsets[i] = invalid_address;
1717     }
1718
1719   // Handle the .eh_frame sections at the end.
1720   gold_assert(!is_gc_pass_one || eh_frame_sections.empty());
1721   for (std::vector<unsigned int>::const_iterator p = eh_frame_sections.begin();
1722        p != eh_frame_sections.end();
1723        ++p)
1724     {
1725       unsigned int i = *p;
1726       const unsigned char* pshdr;
1727       pshdr = section_headers_data + i * This::shdr_size;
1728       typename This::Shdr shdr(pshdr);
1729
1730       this->layout_eh_frame_section(layout,
1731                                     symbols_data,
1732                                     symbols_size,
1733                                     symbol_names_data,
1734                                     symbol_names_size,
1735                                     i,
1736                                     shdr,
1737                                     reloc_shndx[i],
1738                                     reloc_type[i]);
1739     }
1740
1741   // When building a .gdb_index section, scan the .debug_info and
1742   // .debug_types sections.
1743   gold_assert(!is_gc_pass_one
1744               || (debug_info_sections.empty() && debug_types_sections.empty()));
1745   for (std::vector<unsigned int>::const_iterator p
1746            = debug_info_sections.begin();
1747        p != debug_info_sections.end();
1748        ++p)
1749     {
1750       unsigned int i = *p;
1751       layout->add_to_gdb_index(false, this, symbols_data, symbols_size,
1752                                i, reloc_shndx[i], reloc_type[i]);
1753     }
1754   for (std::vector<unsigned int>::const_iterator p
1755            = debug_types_sections.begin();
1756        p != debug_types_sections.end();
1757        ++p)
1758     {
1759       unsigned int i = *p;
1760       layout->add_to_gdb_index(true, this, symbols_data, symbols_size,
1761                                i, reloc_shndx[i], reloc_type[i]);
1762     }
1763
1764   if (is_gc_pass_two)
1765     {
1766       delete[] gc_sd->section_headers_data;
1767       delete[] gc_sd->section_names_data;
1768       delete[] gc_sd->symbols_data;
1769       delete[] gc_sd->symbol_names_data;
1770       this->set_symbols_data(NULL);
1771     }
1772   else
1773     {
1774       delete sd->section_headers;
1775       sd->section_headers = NULL;
1776       delete sd->section_names;
1777       sd->section_names = NULL;
1778     }
1779 }
1780
1781 // Layout sections whose layout was deferred while waiting for
1782 // input files from a plugin.
1783
1784 template<int size, bool big_endian>
1785 void
1786 Sized_relobj_file<size, big_endian>::do_layout_deferred_sections(Layout* layout)
1787 {
1788   typename std::vector<Deferred_layout>::iterator deferred;
1789
1790   for (deferred = this->deferred_layout_.begin();
1791        deferred != this->deferred_layout_.end();
1792        ++deferred)
1793     {
1794       typename This::Shdr shdr(deferred->shdr_data_);
1795       // If the section is not included, it is because the garbage collector
1796       // decided it is not needed.  Avoid reverting that decision.
1797       if (!this->is_section_included(deferred->shndx_))
1798         continue;
1799
1800       if (parameters->options().relocatable()
1801           || deferred->name_ != ".eh_frame"
1802           || !this->check_eh_frame_flags(&shdr))
1803         this->layout_section(layout, deferred->shndx_, deferred->name_.c_str(),
1804                              shdr, deferred->reloc_shndx_,
1805                              deferred->reloc_type_);
1806       else
1807         {
1808           // Reading the symbols again here may be slow.
1809           Read_symbols_data sd;
1810           this->read_symbols(&sd);
1811           this->layout_eh_frame_section(layout,
1812                                         sd.symbols->data(),
1813                                         sd.symbols_size,
1814                                         sd.symbol_names->data(),
1815                                         sd.symbol_names_size,
1816                                         deferred->shndx_,
1817                                         shdr,
1818                                         deferred->reloc_shndx_,
1819                                         deferred->reloc_type_);
1820         }
1821     }
1822
1823   this->deferred_layout_.clear();
1824
1825   // Now handle the deferred relocation sections.
1826
1827   Output_sections& out_sections(this->output_sections());
1828   std::vector<Address>& out_section_offsets(this->section_offsets());
1829
1830   for (deferred = this->deferred_layout_relocs_.begin();
1831        deferred != this->deferred_layout_relocs_.end();
1832        ++deferred)
1833     {
1834       unsigned int shndx = deferred->shndx_;
1835       typename This::Shdr shdr(deferred->shdr_data_);
1836       unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1837
1838       Output_section* data_section = out_sections[data_shndx];
1839       if (data_section == NULL)
1840         {
1841           out_sections[shndx] = NULL;
1842           out_section_offsets[shndx] = invalid_address;
1843           continue;
1844         }
1845
1846       Relocatable_relocs* rr = new Relocatable_relocs();
1847       this->set_relocatable_relocs(shndx, rr);
1848
1849       Output_section* os = layout->layout_reloc(this, shndx, shdr,
1850                                                 data_section, rr);
1851       out_sections[shndx] = os;
1852       out_section_offsets[shndx] = invalid_address;
1853     }
1854 }
1855
1856 // Add the symbols to the symbol table.
1857
1858 template<int size, bool big_endian>
1859 void
1860 Sized_relobj_file<size, big_endian>::do_add_symbols(Symbol_table* symtab,
1861                                                     Read_symbols_data* sd,
1862                                                     Layout*)
1863 {
1864   if (sd->symbols == NULL)
1865     {
1866       gold_assert(sd->symbol_names == NULL);
1867       return;
1868     }
1869
1870   const int sym_size = This::sym_size;
1871   size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1872                      / sym_size);
1873   if (symcount * sym_size != sd->symbols_size - sd->external_symbols_offset)
1874     {
1875       this->error(_("size of symbols is not multiple of symbol size"));
1876       return;
1877     }
1878
1879   this->symbols_.resize(symcount);
1880
1881   const char* sym_names =
1882     reinterpret_cast<const char*>(sd->symbol_names->data());
1883   symtab->add_from_relobj(this,
1884                           sd->symbols->data() + sd->external_symbols_offset,
1885                           symcount, this->local_symbol_count_,
1886                           sym_names, sd->symbol_names_size,
1887                           &this->symbols_,
1888                           &this->defined_count_);
1889
1890   delete sd->symbols;
1891   sd->symbols = NULL;
1892   delete sd->symbol_names;
1893   sd->symbol_names = NULL;
1894 }
1895
1896 // Find out if this object, that is a member of a lib group, should be included
1897 // in the link. We check every symbol defined by this object. If the symbol
1898 // table has a strong undefined reference to that symbol, we have to include
1899 // the object.
1900
1901 template<int size, bool big_endian>
1902 Archive::Should_include
1903 Sized_relobj_file<size, big_endian>::do_should_include_member(
1904     Symbol_table* symtab,
1905     Layout* layout,
1906     Read_symbols_data* sd,
1907     std::string* why)
1908 {
1909   char* tmpbuf = NULL;
1910   size_t tmpbuflen = 0;
1911   const char* sym_names =
1912       reinterpret_cast<const char*>(sd->symbol_names->data());
1913   const unsigned char* syms =
1914       sd->symbols->data() + sd->external_symbols_offset;
1915   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1916   size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1917                          / sym_size);
1918
1919   const unsigned char* p = syms;
1920
1921   for (size_t i = 0; i < symcount; ++i, p += sym_size)
1922     {
1923       elfcpp::Sym<size, big_endian> sym(p);
1924       unsigned int st_shndx = sym.get_st_shndx();
1925       if (st_shndx == elfcpp::SHN_UNDEF)
1926         continue;
1927
1928       unsigned int st_name = sym.get_st_name();
1929       const char* name = sym_names + st_name;
1930       Symbol* symbol;
1931       Archive::Should_include t = Archive::should_include_member(symtab,
1932                                                                  layout,
1933                                                                  name,
1934                                                                  &symbol, why,
1935                                                                  &tmpbuf,
1936                                                                  &tmpbuflen);
1937       if (t == Archive::SHOULD_INCLUDE_YES)
1938         {
1939           if (tmpbuf != NULL)
1940             free(tmpbuf);
1941           return t;
1942         }
1943     }
1944   if (tmpbuf != NULL)
1945     free(tmpbuf);
1946   return Archive::SHOULD_INCLUDE_UNKNOWN;
1947 }
1948
1949 // Iterate over global defined symbols, calling a visitor class V for each.
1950
1951 template<int size, bool big_endian>
1952 void
1953 Sized_relobj_file<size, big_endian>::do_for_all_global_symbols(
1954     Read_symbols_data* sd,
1955     Library_base::Symbol_visitor_base* v)
1956 {
1957   const char* sym_names =
1958       reinterpret_cast<const char*>(sd->symbol_names->data());
1959   const unsigned char* syms =
1960       sd->symbols->data() + sd->external_symbols_offset;
1961   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1962   size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1963                      / sym_size);
1964   const unsigned char* p = syms;
1965
1966   for (size_t i = 0; i < symcount; ++i, p += sym_size)
1967     {
1968       elfcpp::Sym<size, big_endian> sym(p);
1969       if (sym.get_st_shndx() != elfcpp::SHN_UNDEF)
1970         v->visit(sym_names + sym.get_st_name());
1971     }
1972 }
1973
1974 // Return whether the local symbol SYMNDX has a PLT offset.
1975
1976 template<int size, bool big_endian>
1977 bool
1978 Sized_relobj_file<size, big_endian>::local_has_plt_offset(
1979     unsigned int symndx) const
1980 {
1981   typename Local_plt_offsets::const_iterator p =
1982     this->local_plt_offsets_.find(symndx);
1983   return p != this->local_plt_offsets_.end();
1984 }
1985
1986 // Get the PLT offset of a local symbol.
1987
1988 template<int size, bool big_endian>
1989 unsigned int
1990 Sized_relobj_file<size, big_endian>::do_local_plt_offset(
1991     unsigned int symndx) const
1992 {
1993   typename Local_plt_offsets::const_iterator p =
1994     this->local_plt_offsets_.find(symndx);
1995   gold_assert(p != this->local_plt_offsets_.end());
1996   return p->second;
1997 }
1998
1999 // Set the PLT offset of a local symbol.
2000
2001 template<int size, bool big_endian>
2002 void
2003 Sized_relobj_file<size, big_endian>::set_local_plt_offset(
2004     unsigned int symndx, unsigned int plt_offset)
2005 {
2006   std::pair<typename Local_plt_offsets::iterator, bool> ins =
2007     this->local_plt_offsets_.insert(std::make_pair(symndx, plt_offset));
2008   gold_assert(ins.second);
2009 }
2010
2011 // First pass over the local symbols.  Here we add their names to
2012 // *POOL and *DYNPOOL, and we store the symbol value in
2013 // THIS->LOCAL_VALUES_.  This function is always called from a
2014 // singleton thread.  This is followed by a call to
2015 // finalize_local_symbols.
2016
2017 template<int size, bool big_endian>
2018 void
2019 Sized_relobj_file<size, big_endian>::do_count_local_symbols(Stringpool* pool,
2020                                                             Stringpool* dynpool)
2021 {
2022   gold_assert(this->symtab_shndx_ != -1U);
2023   if (this->symtab_shndx_ == 0)
2024     {
2025       // This object has no symbols.  Weird but legal.
2026       return;
2027     }
2028
2029   // Read the symbol table section header.
2030   const unsigned int symtab_shndx = this->symtab_shndx_;
2031   typename This::Shdr symtabshdr(this,
2032                                  this->elf_file_.section_header(symtab_shndx));
2033   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
2034
2035   // Read the local symbols.
2036   const int sym_size = This::sym_size;
2037   const unsigned int loccount = this->local_symbol_count_;
2038   gold_assert(loccount == symtabshdr.get_sh_info());
2039   off_t locsize = loccount * sym_size;
2040   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
2041                                               locsize, true, true);
2042
2043   // Read the symbol names.
2044   const unsigned int strtab_shndx =
2045     this->adjust_shndx(symtabshdr.get_sh_link());
2046   section_size_type strtab_size;
2047   const unsigned char* pnamesu = this->section_contents(strtab_shndx,
2048                                                         &strtab_size,
2049                                                         true);
2050   const char* pnames = reinterpret_cast<const char*>(pnamesu);
2051
2052   // Loop over the local symbols.
2053
2054   const Output_sections& out_sections(this->output_sections());
2055   unsigned int shnum = this->shnum();
2056   unsigned int count = 0;
2057   unsigned int dyncount = 0;
2058   // Skip the first, dummy, symbol.
2059   psyms += sym_size;
2060   bool strip_all = parameters->options().strip_all();
2061   bool discard_all = parameters->options().discard_all();
2062   bool discard_locals = parameters->options().discard_locals();
2063   for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
2064     {
2065       elfcpp::Sym<size, big_endian> sym(psyms);
2066
2067       Symbol_value<size>& lv(this->local_values_[i]);
2068
2069       bool is_ordinary;
2070       unsigned int shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
2071                                                   &is_ordinary);
2072       lv.set_input_shndx(shndx, is_ordinary);
2073
2074       if (sym.get_st_type() == elfcpp::STT_SECTION)
2075         lv.set_is_section_symbol();
2076       else if (sym.get_st_type() == elfcpp::STT_TLS)
2077         lv.set_is_tls_symbol();
2078       else if (sym.get_st_type() == elfcpp::STT_GNU_IFUNC)
2079         lv.set_is_ifunc_symbol();
2080
2081       // Save the input symbol value for use in do_finalize_local_symbols().
2082       lv.set_input_value(sym.get_st_value());
2083
2084       // Decide whether this symbol should go into the output file.
2085
2086       if ((shndx < shnum && out_sections[shndx] == NULL)
2087           || shndx == this->discarded_eh_frame_shndx_)
2088         {
2089           lv.set_no_output_symtab_entry();
2090           gold_assert(!lv.needs_output_dynsym_entry());
2091           continue;
2092         }
2093
2094       if (sym.get_st_type() == elfcpp::STT_SECTION)
2095         {
2096           lv.set_no_output_symtab_entry();
2097           gold_assert(!lv.needs_output_dynsym_entry());
2098           continue;
2099         }
2100
2101       if (sym.get_st_name() >= strtab_size)
2102         {
2103           this->error(_("local symbol %u section name out of range: %u >= %u"),
2104                       i, sym.get_st_name(),
2105                       static_cast<unsigned int>(strtab_size));
2106           lv.set_no_output_symtab_entry();
2107           continue;
2108         }
2109
2110       const char* name = pnames + sym.get_st_name();
2111
2112       // If needed, add the symbol to the dynamic symbol table string pool.
2113       if (lv.needs_output_dynsym_entry())
2114         {
2115           dynpool->add(name, true, NULL);
2116           ++dyncount;
2117         }
2118
2119       if (strip_all
2120           || (discard_all && lv.may_be_discarded_from_output_symtab()))
2121         {
2122           lv.set_no_output_symtab_entry();
2123           continue;
2124         }
2125
2126       // If --discard-locals option is used, discard all temporary local
2127       // symbols.  These symbols start with system-specific local label
2128       // prefixes, typically .L for ELF system.  We want to be compatible
2129       // with GNU ld so here we essentially use the same check in
2130       // bfd_is_local_label().  The code is different because we already
2131       // know that:
2132       //
2133       //   - the symbol is local and thus cannot have global or weak binding.
2134       //   - the symbol is not a section symbol.
2135       //   - the symbol has a name.
2136       //
2137       // We do not discard a symbol if it needs a dynamic symbol entry.
2138       if (discard_locals
2139           && sym.get_st_type() != elfcpp::STT_FILE
2140           && !lv.needs_output_dynsym_entry()
2141           && lv.may_be_discarded_from_output_symtab()
2142           && parameters->target().is_local_label_name(name))
2143         {
2144           lv.set_no_output_symtab_entry();
2145           continue;
2146         }
2147
2148       // Discard the local symbol if -retain_symbols_file is specified
2149       // and the local symbol is not in that file.
2150       if (!parameters->options().should_retain_symbol(name))
2151         {
2152           lv.set_no_output_symtab_entry();
2153           continue;
2154         }
2155
2156       // Add the symbol to the symbol table string pool.
2157       pool->add(name, true, NULL);
2158       ++count;
2159     }
2160
2161   this->output_local_symbol_count_ = count;
2162   this->output_local_dynsym_count_ = dyncount;
2163 }
2164
2165 // Compute the final value of a local symbol.
2166
2167 template<int size, bool big_endian>
2168 typename Sized_relobj_file<size, big_endian>::Compute_final_local_value_status
2169 Sized_relobj_file<size, big_endian>::compute_final_local_value_internal(
2170     unsigned int r_sym,
2171     const Symbol_value<size>* lv_in,
2172     Symbol_value<size>* lv_out,
2173     bool relocatable,
2174     const Output_sections& out_sections,
2175     const std::vector<Address>& out_offsets,
2176     const Symbol_table* symtab)
2177 {
2178   // We are going to overwrite *LV_OUT, if it has a merged symbol value,
2179   // we may have a memory leak.
2180   gold_assert(lv_out->has_output_value());
2181
2182   bool is_ordinary;
2183   unsigned int shndx = lv_in->input_shndx(&is_ordinary);
2184
2185   // Set the output symbol value.
2186
2187   if (!is_ordinary)
2188     {
2189       if (shndx == elfcpp::SHN_ABS || Symbol::is_common_shndx(shndx))
2190         lv_out->set_output_value(lv_in->input_value());
2191       else
2192         {
2193           this->error(_("unknown section index %u for local symbol %u"),
2194                       shndx, r_sym);
2195           lv_out->set_output_value(0);
2196           return This::CFLV_ERROR;
2197         }
2198     }
2199   else
2200     {
2201       if (shndx >= this->shnum())
2202         {
2203           this->error(_("local symbol %u section index %u out of range"),
2204                       r_sym, shndx);
2205           lv_out->set_output_value(0);
2206           return This::CFLV_ERROR;
2207         }
2208
2209       Output_section* os = out_sections[shndx];
2210       Address secoffset = out_offsets[shndx];
2211       if (symtab->is_section_folded(this, shndx))
2212         {
2213           gold_assert(os == NULL && secoffset == invalid_address);
2214           // Get the os of the section it is folded onto.
2215           Section_id folded = symtab->icf()->get_folded_section(this,
2216                                                                 shndx);
2217           gold_assert(folded.first != NULL);
2218           Sized_relobj_file<size, big_endian>* folded_obj = reinterpret_cast
2219             <Sized_relobj_file<size, big_endian>*>(folded.first);
2220           os = folded_obj->output_section(folded.second);
2221           gold_assert(os != NULL);
2222           secoffset = folded_obj->get_output_section_offset(folded.second);
2223
2224           // This could be a relaxed input section.
2225           if (secoffset == invalid_address)
2226             {
2227               const Output_relaxed_input_section* relaxed_section =
2228                 os->find_relaxed_input_section(folded_obj, folded.second);
2229               gold_assert(relaxed_section != NULL);
2230               secoffset = relaxed_section->address() - os->address();
2231             }
2232         }
2233
2234       if (os == NULL)
2235         {
2236           // This local symbol belongs to a section we are discarding.
2237           // In some cases when applying relocations later, we will
2238           // attempt to match it to the corresponding kept section,
2239           // so we leave the input value unchanged here.
2240           return This::CFLV_DISCARDED;
2241         }
2242       else if (secoffset == invalid_address)
2243         {
2244           uint64_t start;
2245
2246           // This is a SHF_MERGE section or one which otherwise
2247           // requires special handling.
2248           if (shndx == this->discarded_eh_frame_shndx_)
2249             {
2250               // This local symbol belongs to a discarded .eh_frame
2251               // section.  Just treat it like the case in which
2252               // os == NULL above.
2253               gold_assert(this->has_eh_frame_);
2254               return This::CFLV_DISCARDED;
2255             }
2256           else if (!lv_in->is_section_symbol())
2257             {
2258               // This is not a section symbol.  We can determine
2259               // the final value now.
2260               lv_out->set_output_value(
2261                   os->output_address(this, shndx, lv_in->input_value()));
2262             }
2263           else if (!os->find_starting_output_address(this, shndx, &start))
2264             {
2265               // This is a section symbol, but apparently not one in a
2266               // merged section.  First check to see if this is a relaxed
2267               // input section.  If so, use its address.  Otherwise just
2268               // use the start of the output section.  This happens with
2269               // relocatable links when the input object has section
2270               // symbols for arbitrary non-merge sections.
2271               const Output_section_data* posd =
2272                 os->find_relaxed_input_section(this, shndx);
2273               if (posd != NULL)
2274                 {
2275                   Address relocatable_link_adjustment =
2276                     relocatable ? os->address() : 0;
2277                   lv_out->set_output_value(posd->address()
2278                                            - relocatable_link_adjustment);
2279                 }
2280               else
2281                 lv_out->set_output_value(os->address());
2282             }
2283           else
2284             {
2285               // We have to consider the addend to determine the
2286               // value to use in a relocation.  START is the start
2287               // of this input section.  If we are doing a relocatable
2288               // link, use offset from start output section instead of
2289               // address.
2290               Address adjusted_start =
2291                 relocatable ? start - os->address() : start;
2292               Merged_symbol_value<size>* msv =
2293                 new Merged_symbol_value<size>(lv_in->input_value(),
2294                                               adjusted_start);
2295               lv_out->set_merged_symbol_value(msv);
2296             }
2297         }
2298       else if (lv_in->is_tls_symbol())
2299         lv_out->set_output_value(os->tls_offset()
2300                                  + secoffset
2301                                  + lv_in->input_value());
2302       else
2303         lv_out->set_output_value((relocatable ? 0 : os->address())
2304                                  + secoffset
2305                                  + lv_in->input_value());
2306     }
2307   return This::CFLV_OK;
2308 }
2309
2310 // Compute final local symbol value.  R_SYM is the index of a local
2311 // symbol in symbol table.  LV points to a symbol value, which is
2312 // expected to hold the input value and to be over-written by the
2313 // final value.  SYMTAB points to a symbol table.  Some targets may want
2314 // to know would-be-finalized local symbol values in relaxation.
2315 // Hence we provide this method.  Since this method updates *LV, a
2316 // callee should make a copy of the original local symbol value and
2317 // use the copy instead of modifying an object's local symbols before
2318 // everything is finalized.  The caller should also free up any allocated
2319 // memory in the return value in *LV.
2320 template<int size, bool big_endian>
2321 typename Sized_relobj_file<size, big_endian>::Compute_final_local_value_status
2322 Sized_relobj_file<size, big_endian>::compute_final_local_value(
2323     unsigned int r_sym,
2324     const Symbol_value<size>* lv_in,
2325     Symbol_value<size>* lv_out,
2326     const Symbol_table* symtab)
2327 {
2328   // This is just a wrapper of compute_final_local_value_internal.
2329   const bool relocatable = parameters->options().relocatable();
2330   const Output_sections& out_sections(this->output_sections());
2331   const std::vector<Address>& out_offsets(this->section_offsets());
2332   return this->compute_final_local_value_internal(r_sym, lv_in, lv_out,
2333                                                   relocatable, out_sections,
2334                                                   out_offsets, symtab);
2335 }
2336
2337 // Finalize the local symbols.  Here we set the final value in
2338 // THIS->LOCAL_VALUES_ and set their output symbol table indexes.
2339 // This function is always called from a singleton thread.  The actual
2340 // output of the local symbols will occur in a separate task.
2341
2342 template<int size, bool big_endian>
2343 unsigned int
2344 Sized_relobj_file<size, big_endian>::do_finalize_local_symbols(
2345     unsigned int index,
2346     off_t off,
2347     Symbol_table* symtab)
2348 {
2349   gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
2350
2351   const unsigned int loccount = this->local_symbol_count_;
2352   this->local_symbol_offset_ = off;
2353
2354   const bool relocatable = parameters->options().relocatable();
2355   const Output_sections& out_sections(this->output_sections());
2356   const std::vector<Address>& out_offsets(this->section_offsets());
2357
2358   for (unsigned int i = 1; i < loccount; ++i)
2359     {
2360       Symbol_value<size>* lv = &this->local_values_[i];
2361
2362       Compute_final_local_value_status cflv_status =
2363         this->compute_final_local_value_internal(i, lv, lv, relocatable,
2364                                                  out_sections, out_offsets,
2365                                                  symtab);
2366       switch (cflv_status)
2367         {
2368         case CFLV_OK:
2369           if (!lv->is_output_symtab_index_set())
2370             {
2371               lv->set_output_symtab_index(index);
2372               ++index;
2373             }
2374           break;
2375         case CFLV_DISCARDED:
2376         case CFLV_ERROR:
2377           // Do nothing.
2378           break;
2379         default:
2380           gold_unreachable();
2381         }
2382     }
2383   return index;
2384 }
2385
2386 // Set the output dynamic symbol table indexes for the local variables.
2387
2388 template<int size, bool big_endian>
2389 unsigned int
2390 Sized_relobj_file<size, big_endian>::do_set_local_dynsym_indexes(
2391     unsigned int index)
2392 {
2393   const unsigned int loccount = this->local_symbol_count_;
2394   for (unsigned int i = 1; i < loccount; ++i)
2395     {
2396       Symbol_value<size>& lv(this->local_values_[i]);
2397       if (lv.needs_output_dynsym_entry())
2398         {
2399           lv.set_output_dynsym_index(index);
2400           ++index;
2401         }
2402     }
2403   return index;
2404 }
2405
2406 // Set the offset where local dynamic symbol information will be stored.
2407 // Returns the count of local symbols contributed to the symbol table by
2408 // this object.
2409
2410 template<int size, bool big_endian>
2411 unsigned int
2412 Sized_relobj_file<size, big_endian>::do_set_local_dynsym_offset(off_t off)
2413 {
2414   gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
2415   this->local_dynsym_offset_ = off;
2416   return this->output_local_dynsym_count_;
2417 }
2418
2419 // If Symbols_data is not NULL get the section flags from here otherwise
2420 // get it from the file.
2421
2422 template<int size, bool big_endian>
2423 uint64_t
2424 Sized_relobj_file<size, big_endian>::do_section_flags(unsigned int shndx)
2425 {
2426   Symbols_data* sd = this->get_symbols_data();
2427   if (sd != NULL)
2428     {
2429       const unsigned char* pshdrs = sd->section_headers_data
2430                                     + This::shdr_size * shndx;
2431       typename This::Shdr shdr(pshdrs);
2432       return shdr.get_sh_flags();
2433     }
2434   // If sd is NULL, read the section header from the file.
2435   return this->elf_file_.section_flags(shndx);
2436 }
2437
2438 // Get the section's ent size from Symbols_data.  Called by get_section_contents
2439 // in icf.cc
2440
2441 template<int size, bool big_endian>
2442 uint64_t
2443 Sized_relobj_file<size, big_endian>::do_section_entsize(unsigned int shndx)
2444 {
2445   Symbols_data* sd = this->get_symbols_data();
2446   gold_assert(sd != NULL);
2447
2448   const unsigned char* pshdrs = sd->section_headers_data
2449                                 + This::shdr_size * shndx;
2450   typename This::Shdr shdr(pshdrs);
2451   return shdr.get_sh_entsize();
2452 }
2453
2454 // Write out the local symbols.
2455
2456 template<int size, bool big_endian>
2457 void
2458 Sized_relobj_file<size, big_endian>::write_local_symbols(
2459     Output_file* of,
2460     const Stringpool* sympool,
2461     const Stringpool* dynpool,
2462     Output_symtab_xindex* symtab_xindex,
2463     Output_symtab_xindex* dynsym_xindex,
2464     off_t symtab_off)
2465 {
2466   const bool strip_all = parameters->options().strip_all();
2467   if (strip_all)
2468     {
2469       if (this->output_local_dynsym_count_ == 0)
2470         return;
2471       this->output_local_symbol_count_ = 0;
2472     }
2473
2474   gold_assert(this->symtab_shndx_ != -1U);
2475   if (this->symtab_shndx_ == 0)
2476     {
2477       // This object has no symbols.  Weird but legal.
2478       return;
2479     }
2480
2481   // Read the symbol table section header.
2482   const unsigned int symtab_shndx = this->symtab_shndx_;
2483   typename This::Shdr symtabshdr(this,
2484                                  this->elf_file_.section_header(symtab_shndx));
2485   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
2486   const unsigned int loccount = this->local_symbol_count_;
2487   gold_assert(loccount == symtabshdr.get_sh_info());
2488
2489   // Read the local symbols.
2490   const int sym_size = This::sym_size;
2491   off_t locsize = loccount * sym_size;
2492   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
2493                                               locsize, true, false);
2494
2495   // Read the symbol names.
2496   const unsigned int strtab_shndx =
2497     this->adjust_shndx(symtabshdr.get_sh_link());
2498   section_size_type strtab_size;
2499   const unsigned char* pnamesu = this->section_contents(strtab_shndx,
2500                                                         &strtab_size,
2501                                                         false);
2502   const char* pnames = reinterpret_cast<const char*>(pnamesu);
2503
2504   // Get views into the output file for the portions of the symbol table
2505   // and the dynamic symbol table that we will be writing.
2506   off_t output_size = this->output_local_symbol_count_ * sym_size;
2507   unsigned char* oview = NULL;
2508   if (output_size > 0)
2509     oview = of->get_output_view(symtab_off + this->local_symbol_offset_,
2510                                 output_size);
2511
2512   off_t dyn_output_size = this->output_local_dynsym_count_ * sym_size;
2513   unsigned char* dyn_oview = NULL;
2514   if (dyn_output_size > 0)
2515     dyn_oview = of->get_output_view(this->local_dynsym_offset_,
2516                                     dyn_output_size);
2517
2518   const Output_sections out_sections(this->output_sections());
2519
2520   gold_assert(this->local_values_.size() == loccount);
2521
2522   unsigned char* ov = oview;
2523   unsigned char* dyn_ov = dyn_oview;
2524   psyms += sym_size;
2525   for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
2526     {
2527       elfcpp::Sym<size, big_endian> isym(psyms);
2528
2529       Symbol_value<size>& lv(this->local_values_[i]);
2530
2531       bool is_ordinary;
2532       unsigned int st_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
2533                                                      &is_ordinary);
2534       if (is_ordinary)
2535         {
2536           gold_assert(st_shndx < out_sections.size());
2537           if (out_sections[st_shndx] == NULL)
2538             continue;
2539           st_shndx = out_sections[st_shndx]->out_shndx();
2540           if (st_shndx >= elfcpp::SHN_LORESERVE)
2541             {
2542               if (lv.has_output_symtab_entry())
2543                 symtab_xindex->add(lv.output_symtab_index(), st_shndx);
2544               if (lv.has_output_dynsym_entry())
2545                 dynsym_xindex->add(lv.output_dynsym_index(), st_shndx);
2546               st_shndx = elfcpp::SHN_XINDEX;
2547             }
2548         }
2549
2550       // Write the symbol to the output symbol table.
2551       if (lv.has_output_symtab_entry())
2552         {
2553           elfcpp::Sym_write<size, big_endian> osym(ov);
2554
2555           gold_assert(isym.get_st_name() < strtab_size);
2556           const char* name = pnames + isym.get_st_name();
2557           osym.put_st_name(sympool->get_offset(name));
2558           osym.put_st_value(this->local_values_[i].value(this, 0));
2559           osym.put_st_size(isym.get_st_size());
2560           osym.put_st_info(isym.get_st_info());
2561           osym.put_st_other(isym.get_st_other());
2562           osym.put_st_shndx(st_shndx);
2563
2564           ov += sym_size;
2565         }
2566
2567       // Write the symbol to the output dynamic symbol table.
2568       if (lv.has_output_dynsym_entry())
2569         {
2570           gold_assert(dyn_ov < dyn_oview + dyn_output_size);
2571           elfcpp::Sym_write<size, big_endian> osym(dyn_ov);
2572
2573           gold_assert(isym.get_st_name() < strtab_size);
2574           const char* name = pnames + isym.get_st_name();
2575           osym.put_st_name(dynpool->get_offset(name));
2576           osym.put_st_value(this->local_values_[i].value(this, 0));
2577           osym.put_st_size(isym.get_st_size());
2578           osym.put_st_info(isym.get_st_info());
2579           osym.put_st_other(isym.get_st_other());
2580           osym.put_st_shndx(st_shndx);
2581
2582           dyn_ov += sym_size;
2583         }
2584     }
2585
2586
2587   if (output_size > 0)
2588     {
2589       gold_assert(ov - oview == output_size);
2590       of->write_output_view(symtab_off + this->local_symbol_offset_,
2591                             output_size, oview);
2592     }
2593
2594   if (dyn_output_size > 0)
2595     {
2596       gold_assert(dyn_ov - dyn_oview == dyn_output_size);
2597       of->write_output_view(this->local_dynsym_offset_, dyn_output_size,
2598                             dyn_oview);
2599     }
2600 }
2601
2602 // Set *INFO to symbolic information about the offset OFFSET in the
2603 // section SHNDX.  Return true if we found something, false if we
2604 // found nothing.
2605
2606 template<int size, bool big_endian>
2607 bool
2608 Sized_relobj_file<size, big_endian>::get_symbol_location_info(
2609     unsigned int shndx,
2610     off_t offset,
2611     Symbol_location_info* info)
2612 {
2613   if (this->symtab_shndx_ == 0)
2614     return false;
2615
2616   section_size_type symbols_size;
2617   const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
2618                                                         &symbols_size,
2619                                                         false);
2620
2621   unsigned int symbol_names_shndx =
2622     this->adjust_shndx(this->section_link(this->symtab_shndx_));
2623   section_size_type names_size;
2624   const unsigned char* symbol_names_u =
2625     this->section_contents(symbol_names_shndx, &names_size, false);
2626   const char* symbol_names = reinterpret_cast<const char*>(symbol_names_u);
2627
2628   const int sym_size = This::sym_size;
2629   const size_t count = symbols_size / sym_size;
2630
2631   const unsigned char* p = symbols;
2632   for (size_t i = 0; i < count; ++i, p += sym_size)
2633     {
2634       elfcpp::Sym<size, big_endian> sym(p);
2635
2636       if (sym.get_st_type() == elfcpp::STT_FILE)
2637         {
2638           if (sym.get_st_name() >= names_size)
2639             info->source_file = "(invalid)";
2640           else
2641             info->source_file = symbol_names + sym.get_st_name();
2642           continue;
2643         }
2644
2645       bool is_ordinary;
2646       unsigned int st_shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
2647                                                      &is_ordinary);
2648       if (is_ordinary
2649           && st_shndx == shndx
2650           && static_cast<off_t>(sym.get_st_value()) <= offset
2651           && (static_cast<off_t>(sym.get_st_value() + sym.get_st_size())
2652               > offset))
2653         {
2654           if (sym.get_st_name() > names_size)
2655             info->enclosing_symbol_name = "(invalid)";
2656           else
2657             {
2658               info->enclosing_symbol_name = symbol_names + sym.get_st_name();
2659               if (parameters->options().do_demangle())
2660                 {
2661                   char* demangled_name = cplus_demangle(
2662                       info->enclosing_symbol_name.c_str(),
2663                       DMGL_ANSI | DMGL_PARAMS);
2664                   if (demangled_name != NULL)
2665                     {
2666                       info->enclosing_symbol_name.assign(demangled_name);
2667                       free(demangled_name);
2668                     }
2669                 }
2670             }
2671           return true;
2672         }
2673     }
2674
2675   return false;
2676 }
2677
2678 // Look for a kept section corresponding to the given discarded section,
2679 // and return its output address.  This is used only for relocations in
2680 // debugging sections.  If we can't find the kept section, return 0.
2681
2682 template<int size, bool big_endian>
2683 typename Sized_relobj_file<size, big_endian>::Address
2684 Sized_relobj_file<size, big_endian>::map_to_kept_section(
2685     unsigned int shndx,
2686     bool* found) const
2687 {
2688   Relobj* kept_object;
2689   unsigned int kept_shndx;
2690   if (this->get_kept_comdat_section(shndx, &kept_object, &kept_shndx))
2691     {
2692       Sized_relobj_file<size, big_endian>* kept_relobj =
2693         static_cast<Sized_relobj_file<size, big_endian>*>(kept_object);
2694       Output_section* os = kept_relobj->output_section(kept_shndx);
2695       Address offset = kept_relobj->get_output_section_offset(kept_shndx);
2696       if (os != NULL && offset != invalid_address)
2697         {
2698           *found = true;
2699           return os->address() + offset;
2700         }
2701     }
2702   *found = false;
2703   return 0;
2704 }
2705
2706 // Get symbol counts.
2707
2708 template<int size, bool big_endian>
2709 void
2710 Sized_relobj_file<size, big_endian>::do_get_global_symbol_counts(
2711     const Symbol_table*,
2712     size_t* defined,
2713     size_t* used) const
2714 {
2715   *defined = this->defined_count_;
2716   size_t count = 0;
2717   for (typename Symbols::const_iterator p = this->symbols_.begin();
2718        p != this->symbols_.end();
2719        ++p)
2720     if (*p != NULL
2721         && (*p)->source() == Symbol::FROM_OBJECT
2722         && (*p)->object() == this
2723         && (*p)->is_defined())
2724       ++count;
2725   *used = count;
2726 }
2727
2728 // Return a view of the decompressed contents of a section.  Set *PLEN
2729 // to the size.  Set *IS_NEW to true if the contents need to be freed
2730 // by the caller.
2731
2732 template<int size, bool big_endian>
2733 const unsigned char*
2734 Sized_relobj_file<size, big_endian>::do_decompressed_section_contents(
2735     unsigned int shndx,
2736     section_size_type* plen,
2737     bool* is_new)
2738 {
2739   section_size_type buffer_size;
2740   const unsigned char* buffer = this->do_section_contents(shndx, &buffer_size,
2741                                                           false);
2742
2743   if (this->compressed_sections_ == NULL)
2744     {
2745       *plen = buffer_size;
2746       *is_new = false;
2747       return buffer;
2748     }
2749
2750   Compressed_section_map::const_iterator p =
2751       this->compressed_sections_->find(shndx);
2752   if (p == this->compressed_sections_->end())
2753     {
2754       *plen = buffer_size;
2755       *is_new = false;
2756       return buffer;
2757     }
2758
2759   section_size_type uncompressed_size = p->second.size;
2760   if (p->second.contents != NULL)
2761     {
2762       *plen = uncompressed_size;
2763       *is_new = false;
2764       return p->second.contents;
2765     }
2766
2767   unsigned char* uncompressed_data = new unsigned char[uncompressed_size];
2768   if (!decompress_input_section(buffer,
2769                                 buffer_size,
2770                                 uncompressed_data,
2771                                 uncompressed_size))
2772     this->error(_("could not decompress section %s"),
2773                 this->do_section_name(shndx).c_str());
2774
2775   // We could cache the results in p->second.contents and store
2776   // false in *IS_NEW, but build_compressed_section_map() would
2777   // have done so if it had expected it to be profitable.  If
2778   // we reach this point, we expect to need the contents only
2779   // once in this pass.
2780   *plen = uncompressed_size;
2781   *is_new = true;
2782   return uncompressed_data;
2783 }
2784
2785 // Discard any buffers of uncompressed sections.  This is done
2786 // at the end of the Add_symbols task.
2787
2788 template<int size, bool big_endian>
2789 void
2790 Sized_relobj_file<size, big_endian>::do_discard_decompressed_sections()
2791 {
2792   if (this->compressed_sections_ == NULL)
2793     return;
2794
2795   for (Compressed_section_map::iterator p = this->compressed_sections_->begin();
2796        p != this->compressed_sections_->end();
2797        ++p)
2798     {
2799       if (p->second.contents != NULL)
2800         {
2801           delete[] p->second.contents;
2802           p->second.contents = NULL;
2803         }
2804     }
2805 }
2806
2807 // Input_objects methods.
2808
2809 // Add a regular relocatable object to the list.  Return false if this
2810 // object should be ignored.
2811
2812 bool
2813 Input_objects::add_object(Object* obj)
2814 {
2815   // Print the filename if the -t/--trace option is selected.
2816   if (parameters->options().trace())
2817     gold_info("%s", obj->name().c_str());
2818
2819   if (!obj->is_dynamic())
2820     this->relobj_list_.push_back(static_cast<Relobj*>(obj));
2821   else
2822     {
2823       // See if this is a duplicate SONAME.
2824       Dynobj* dynobj = static_cast<Dynobj*>(obj);
2825       const char* soname = dynobj->soname();
2826
2827       std::pair<Unordered_set<std::string>::iterator, bool> ins =
2828         this->sonames_.insert(soname);
2829       if (!ins.second)
2830         {
2831           // We have already seen a dynamic object with this soname.
2832           return false;
2833         }
2834
2835       this->dynobj_list_.push_back(dynobj);
2836     }
2837
2838   // Add this object to the cross-referencer if requested.
2839   if (parameters->options().user_set_print_symbol_counts()
2840       || parameters->options().cref())
2841     {
2842       if (this->cref_ == NULL)
2843         this->cref_ = new Cref();
2844       this->cref_->add_object(obj);
2845     }
2846
2847   return true;
2848 }
2849
2850 // For each dynamic object, record whether we've seen all of its
2851 // explicit dependencies.
2852
2853 void
2854 Input_objects::check_dynamic_dependencies() const
2855 {
2856   bool issued_copy_dt_needed_error = false;
2857   for (Dynobj_list::const_iterator p = this->dynobj_list_.begin();
2858        p != this->dynobj_list_.end();
2859        ++p)
2860     {
2861       const Dynobj::Needed& needed((*p)->needed());
2862       bool found_all = true;
2863       Dynobj::Needed::const_iterator pneeded;
2864       for (pneeded = needed.begin(); pneeded != needed.end(); ++pneeded)
2865         {
2866           if (this->sonames_.find(*pneeded) == this->sonames_.end())
2867             {
2868               found_all = false;
2869               break;
2870             }
2871         }
2872       (*p)->set_has_unknown_needed_entries(!found_all);
2873
2874       // --copy-dt-needed-entries aka --add-needed is a GNU ld option
2875       // that gold does not support.  However, they cause no trouble
2876       // unless there is a DT_NEEDED entry that we don't know about;
2877       // warn only in that case.
2878       if (!found_all
2879           && !issued_copy_dt_needed_error
2880           && (parameters->options().copy_dt_needed_entries()
2881               || parameters->options().add_needed()))
2882         {
2883           const char* optname;
2884           if (parameters->options().copy_dt_needed_entries())
2885             optname = "--copy-dt-needed-entries";
2886           else
2887             optname = "--add-needed";
2888           gold_error(_("%s is not supported but is required for %s in %s"),
2889                      optname, (*pneeded).c_str(), (*p)->name().c_str());
2890           issued_copy_dt_needed_error = true;
2891         }
2892     }
2893 }
2894
2895 // Start processing an archive.
2896
2897 void
2898 Input_objects::archive_start(Archive* archive)
2899 {
2900   if (parameters->options().user_set_print_symbol_counts()
2901       || parameters->options().cref())
2902     {
2903       if (this->cref_ == NULL)
2904         this->cref_ = new Cref();
2905       this->cref_->add_archive_start(archive);
2906     }
2907 }
2908
2909 // Stop processing an archive.
2910
2911 void
2912 Input_objects::archive_stop(Archive* archive)
2913 {
2914   if (parameters->options().user_set_print_symbol_counts()
2915       || parameters->options().cref())
2916     this->cref_->add_archive_stop(archive);
2917 }
2918
2919 // Print symbol counts
2920
2921 void
2922 Input_objects::print_symbol_counts(const Symbol_table* symtab) const
2923 {
2924   if (parameters->options().user_set_print_symbol_counts()
2925       && this->cref_ != NULL)
2926     this->cref_->print_symbol_counts(symtab);
2927 }
2928
2929 // Print a cross reference table.
2930
2931 void
2932 Input_objects::print_cref(const Symbol_table* symtab, FILE* f) const
2933 {
2934   if (parameters->options().cref() && this->cref_ != NULL)
2935     this->cref_->print_cref(symtab, f);
2936 }
2937
2938 // Relocate_info methods.
2939
2940 // Return a string describing the location of a relocation when file
2941 // and lineno information is not available.  This is only used in
2942 // error messages.
2943
2944 template<int size, bool big_endian>
2945 std::string
2946 Relocate_info<size, big_endian>::location(size_t, off_t offset) const
2947 {
2948   Sized_dwarf_line_info<size, big_endian> line_info(this->object);
2949   std::string ret = line_info.addr2line(this->data_shndx, offset, NULL);
2950   if (!ret.empty())
2951     return ret;
2952
2953   ret = this->object->name();
2954
2955   Symbol_location_info info;
2956   if (this->object->get_symbol_location_info(this->data_shndx, offset, &info))
2957     {
2958       if (!info.source_file.empty())
2959         {
2960           ret += ":";
2961           ret += info.source_file;
2962         }
2963       size_t len = info.enclosing_symbol_name.length() + 100;
2964       char* buf = new char[len];
2965       snprintf(buf, len, _(":function %s"),
2966                info.enclosing_symbol_name.c_str());
2967       ret += buf;
2968       delete[] buf;
2969       return ret;
2970     }
2971
2972   ret += "(";
2973   ret += this->object->section_name(this->data_shndx);
2974   char buf[100];
2975   snprintf(buf, sizeof buf, "+0x%lx)", static_cast<long>(offset));
2976   ret += buf;
2977   return ret;
2978 }
2979
2980 } // End namespace gold.
2981
2982 namespace
2983 {
2984
2985 using namespace gold;
2986
2987 // Read an ELF file with the header and return the appropriate
2988 // instance of Object.
2989
2990 template<int size, bool big_endian>
2991 Object*
2992 make_elf_sized_object(const std::string& name, Input_file* input_file,
2993                       off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr,
2994                       bool* punconfigured)
2995 {
2996   Target* target = select_target(input_file, offset,
2997                                  ehdr.get_e_machine(), size, big_endian,
2998                                  ehdr.get_e_ident()[elfcpp::EI_OSABI],
2999                                  ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
3000   if (target == NULL)
3001     gold_fatal(_("%s: unsupported ELF machine number %d"),
3002                name.c_str(), ehdr.get_e_machine());
3003
3004   if (!parameters->target_valid())
3005     set_parameters_target(target);
3006   else if (target != &parameters->target())
3007     {
3008       if (punconfigured != NULL)
3009         *punconfigured = true;
3010       else
3011         gold_error(_("%s: incompatible target"), name.c_str());
3012       return NULL;
3013     }
3014
3015   return target->make_elf_object<size, big_endian>(name, input_file, offset,
3016                                                    ehdr);
3017 }
3018
3019 } // End anonymous namespace.
3020
3021 namespace gold
3022 {
3023
3024 // Return whether INPUT_FILE is an ELF object.
3025
3026 bool
3027 is_elf_object(Input_file* input_file, off_t offset,
3028               const unsigned char** start, int* read_size)
3029 {
3030   off_t filesize = input_file->file().filesize();
3031   int want = elfcpp::Elf_recognizer::max_header_size;
3032   if (filesize - offset < want)
3033     want = filesize - offset;
3034
3035   const unsigned char* p = input_file->file().get_view(offset, 0, want,
3036                                                        true, false);
3037   *start = p;
3038   *read_size = want;
3039
3040   return elfcpp::Elf_recognizer::is_elf_file(p, want);
3041 }
3042
3043 // Read an ELF file and return the appropriate instance of Object.
3044
3045 Object*
3046 make_elf_object(const std::string& name, Input_file* input_file, off_t offset,
3047                 const unsigned char* p, section_offset_type bytes,
3048                 bool* punconfigured)
3049 {
3050   if (punconfigured != NULL)
3051     *punconfigured = false;
3052
3053   std::string error;
3054   bool big_endian = false;
3055   int size = 0;
3056   if (!elfcpp::Elf_recognizer::is_valid_header(p, bytes, &size,
3057                                                &big_endian, &error))
3058     {
3059       gold_error(_("%s: %s"), name.c_str(), error.c_str());
3060       return NULL;
3061     }
3062
3063   if (size == 32)
3064     {
3065       if (big_endian)
3066         {
3067 #ifdef HAVE_TARGET_32_BIG
3068           elfcpp::Ehdr<32, true> ehdr(p);
3069           return make_elf_sized_object<32, true>(name, input_file,
3070                                                  offset, ehdr, punconfigured);
3071 #else
3072           if (punconfigured != NULL)
3073             *punconfigured = true;
3074           else
3075             gold_error(_("%s: not configured to support "
3076                          "32-bit big-endian object"),
3077                        name.c_str());
3078           return NULL;
3079 #endif
3080         }
3081       else
3082         {
3083 #ifdef HAVE_TARGET_32_LITTLE
3084           elfcpp::Ehdr<32, false> ehdr(p);
3085           return make_elf_sized_object<32, false>(name, input_file,
3086                                                   offset, ehdr, punconfigured);
3087 #else
3088           if (punconfigured != NULL)
3089             *punconfigured = true;
3090           else
3091             gold_error(_("%s: not configured to support "
3092                          "32-bit little-endian object"),
3093                        name.c_str());
3094           return NULL;
3095 #endif
3096         }
3097     }
3098   else if (size == 64)
3099     {
3100       if (big_endian)
3101         {
3102 #ifdef HAVE_TARGET_64_BIG
3103           elfcpp::Ehdr<64, true> ehdr(p);
3104           return make_elf_sized_object<64, true>(name, input_file,
3105                                                  offset, ehdr, punconfigured);
3106 #else
3107           if (punconfigured != NULL)
3108             *punconfigured = true;
3109           else
3110             gold_error(_("%s: not configured to support "
3111                          "64-bit big-endian object"),
3112                        name.c_str());
3113           return NULL;
3114 #endif
3115         }
3116       else
3117         {
3118 #ifdef HAVE_TARGET_64_LITTLE
3119           elfcpp::Ehdr<64, false> ehdr(p);
3120           return make_elf_sized_object<64, false>(name, input_file,
3121                                                   offset, ehdr, punconfigured);
3122 #else
3123           if (punconfigured != NULL)
3124             *punconfigured = true;
3125           else
3126             gold_error(_("%s: not configured to support "
3127                          "64-bit little-endian object"),
3128                        name.c_str());
3129           return NULL;
3130 #endif
3131         }
3132     }
3133   else
3134     gold_unreachable();
3135 }
3136
3137 // Instantiate the templates we need.
3138
3139 #ifdef HAVE_TARGET_32_LITTLE
3140 template
3141 void
3142 Object::read_section_data<32, false>(elfcpp::Elf_file<32, false, Object>*,
3143                                      Read_symbols_data*);
3144 #endif
3145
3146 #ifdef HAVE_TARGET_32_BIG
3147 template
3148 void
3149 Object::read_section_data<32, true>(elfcpp::Elf_file<32, true, Object>*,
3150                                     Read_symbols_data*);
3151 #endif
3152
3153 #ifdef HAVE_TARGET_64_LITTLE
3154 template
3155 void
3156 Object::read_section_data<64, false>(elfcpp::Elf_file<64, false, Object>*,
3157                                      Read_symbols_data*);
3158 #endif
3159
3160 #ifdef HAVE_TARGET_64_BIG
3161 template
3162 void
3163 Object::read_section_data<64, true>(elfcpp::Elf_file<64, true, Object>*,
3164                                     Read_symbols_data*);
3165 #endif
3166
3167 #ifdef HAVE_TARGET_32_LITTLE
3168 template
3169 class Sized_relobj_file<32, false>;
3170 #endif
3171
3172 #ifdef HAVE_TARGET_32_BIG
3173 template
3174 class Sized_relobj_file<32, true>;
3175 #endif
3176
3177 #ifdef HAVE_TARGET_64_LITTLE
3178 template
3179 class Sized_relobj_file<64, false>;
3180 #endif
3181
3182 #ifdef HAVE_TARGET_64_BIG
3183 template
3184 class Sized_relobj_file<64, true>;
3185 #endif
3186
3187 #ifdef HAVE_TARGET_32_LITTLE
3188 template
3189 struct Relocate_info<32, false>;
3190 #endif
3191
3192 #ifdef HAVE_TARGET_32_BIG
3193 template
3194 struct Relocate_info<32, true>;
3195 #endif
3196
3197 #ifdef HAVE_TARGET_64_LITTLE
3198 template
3199 struct Relocate_info<64, false>;
3200 #endif
3201
3202 #ifdef HAVE_TARGET_64_BIG
3203 template
3204 struct Relocate_info<64, true>;
3205 #endif
3206
3207 #ifdef HAVE_TARGET_32_LITTLE
3208 template
3209 void
3210 Xindex::initialize_symtab_xindex<32, false>(Object*, unsigned int);
3211
3212 template
3213 void
3214 Xindex::read_symtab_xindex<32, false>(Object*, unsigned int,
3215                                       const unsigned char*);
3216 #endif
3217
3218 #ifdef HAVE_TARGET_32_BIG
3219 template
3220 void
3221 Xindex::initialize_symtab_xindex<32, true>(Object*, unsigned int);
3222
3223 template
3224 void
3225 Xindex::read_symtab_xindex<32, true>(Object*, unsigned int,
3226                                      const unsigned char*);
3227 #endif
3228
3229 #ifdef HAVE_TARGET_64_LITTLE
3230 template
3231 void
3232 Xindex::initialize_symtab_xindex<64, false>(Object*, unsigned int);
3233
3234 template
3235 void
3236 Xindex::read_symtab_xindex<64, false>(Object*, unsigned int,
3237                                       const unsigned char*);
3238 #endif
3239
3240 #ifdef HAVE_TARGET_64_BIG
3241 template
3242 void
3243 Xindex::initialize_symtab_xindex<64, true>(Object*, unsigned int);
3244
3245 template
3246 void
3247 Xindex::read_symtab_xindex<64, true>(Object*, unsigned int,
3248                                      const unsigned char*);
3249 #endif
3250
3251 } // End namespace gold.