* layout.cc (Layout::set_segment_offsets): Set p_align to
[platform/upstream/binutils.git] / gold / object.cc
1 // object.cc -- support for an object file for linking in gold
2
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012
4 // Free Software Foundation, Inc.
5 // Written by Ian Lance Taylor <iant@google.com>.
6
7 // This file is part of gold.
8
9 // This program is free software; you can redistribute it and/or modify
10 // it under the terms of the GNU General Public License as published by
11 // the Free Software Foundation; either version 3 of the License, or
12 // (at your option) any later version.
13
14 // This program is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 // GNU General Public License for more details.
18
19 // You should have received a copy of the GNU General Public License
20 // along with this program; if not, write to the Free Software
21 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22 // MA 02110-1301, USA.
23
24 #include "gold.h"
25
26 #include <cerrno>
27 #include <cstring>
28 #include <cstdarg>
29 #include "demangle.h"
30 #include "libiberty.h"
31
32 #include "gc.h"
33 #include "target-select.h"
34 #include "dwarf_reader.h"
35 #include "layout.h"
36 #include "output.h"
37 #include "symtab.h"
38 #include "cref.h"
39 #include "reloc.h"
40 #include "object.h"
41 #include "dynobj.h"
42 #include "plugin.h"
43 #include "compressed_output.h"
44 #include "incremental.h"
45
46 namespace gold
47 {
48
49 // Struct Read_symbols_data.
50
51 // Destroy any remaining File_view objects.
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 // This function is called twice sometimes, two passes, when mapping
1225 // of input sections to output sections must be delayed.
1226 // This is true for the following :
1227 // * Garbage collection (--gc-sections): Some input sections will be
1228 // discarded and hence the assignment must wait until the second pass.
1229 // In the first pass,  it is for setting up some sections as roots to
1230 // a work-list for --gc-sections and to do comdat processing.
1231 // * Identical Code Folding (--icf=<safe,all>): Some input sections
1232 // will be folded and hence the assignment must wait.
1233 // * Using plugins to map some sections to unique segments: Mapping
1234 // some sections to unique segments requires mapping them to unique
1235 // output sections too.  This can be done via plugins now and this
1236 // information is not available in the first pass.
1237
1238 template<int size, bool big_endian>
1239 void
1240 Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
1241                                                Layout* layout,
1242                                                Read_symbols_data* sd)
1243 {
1244   const unsigned int shnum = this->shnum();
1245
1246   /* Should this function be called twice?  */
1247   bool is_two_pass = (parameters->options().gc_sections()
1248                       || parameters->options().icf_enabled()
1249                       || layout->is_unique_segment_for_sections_specified());
1250
1251   /* Only one of is_pass_one and is_pass_two is true.  Both are false when
1252      a two-pass approach is not needed.  */
1253   bool is_pass_one = false;
1254   bool is_pass_two = false;
1255
1256   Symbols_data* gc_sd = NULL;
1257
1258   /* Check if do_layout needs to be two-pass.  If so, find out which pass
1259      should happen.  In the first pass, the data in sd is saved to be used
1260      later in the second pass.  */
1261   if (is_two_pass)
1262     {
1263       gc_sd = this->get_symbols_data();
1264       if (gc_sd == NULL)
1265         {
1266           gold_assert(sd != NULL);
1267           is_pass_one = true;
1268         }
1269       else
1270         {
1271           if (parameters->options().gc_sections())
1272             gold_assert(symtab->gc()->is_worklist_ready());
1273           if (parameters->options().icf_enabled())
1274             gold_assert(symtab->icf()->is_icf_ready()); 
1275           is_pass_two = true;
1276         }
1277     }
1278     
1279   if (shnum == 0)
1280     return;
1281
1282   if (is_pass_one)
1283     {
1284       // During garbage collection save the symbols data to use it when
1285       // re-entering this function.
1286       gc_sd = new Symbols_data;
1287       this->copy_symbols_data(gc_sd, sd, This::shdr_size * shnum);
1288       this->set_symbols_data(gc_sd);
1289     }
1290
1291   const unsigned char* section_headers_data = NULL;
1292   section_size_type section_names_size;
1293   const unsigned char* symbols_data = NULL;
1294   section_size_type symbols_size;
1295   const unsigned char* symbol_names_data = NULL;
1296   section_size_type symbol_names_size;
1297
1298   if (is_two_pass)
1299     {
1300       section_headers_data = gc_sd->section_headers_data;
1301       section_names_size = gc_sd->section_names_size;
1302       symbols_data = gc_sd->symbols_data;
1303       symbols_size = gc_sd->symbols_size;
1304       symbol_names_data = gc_sd->symbol_names_data;
1305       symbol_names_size = gc_sd->symbol_names_size;
1306     }
1307   else
1308     {
1309       section_headers_data = sd->section_headers->data();
1310       section_names_size = sd->section_names_size;
1311       if (sd->symbols != NULL)
1312         symbols_data = sd->symbols->data();
1313       symbols_size = sd->symbols_size;
1314       if (sd->symbol_names != NULL)
1315         symbol_names_data = sd->symbol_names->data();
1316       symbol_names_size = sd->symbol_names_size;
1317     }
1318
1319   // Get the section headers.
1320   const unsigned char* shdrs = section_headers_data;
1321   const unsigned char* pshdrs;
1322
1323   // Get the section names.
1324   const unsigned char* pnamesu = (is_two_pass
1325                                   ? gc_sd->section_names_data
1326                                   : sd->section_names->data());
1327
1328   const char* pnames = reinterpret_cast<const char*>(pnamesu);
1329
1330   // If any input files have been claimed by plugins, we need to defer
1331   // actual layout until the replacement files have arrived.
1332   const bool should_defer_layout =
1333       (parameters->options().has_plugins()
1334        && parameters->options().plugins()->should_defer_layout());
1335   unsigned int num_sections_to_defer = 0;
1336
1337   // For each section, record the index of the reloc section if any.
1338   // Use 0 to mean that there is no reloc section, -1U to mean that
1339   // there is more than one.
1340   std::vector<unsigned int> reloc_shndx(shnum, 0);
1341   std::vector<unsigned int> reloc_type(shnum, elfcpp::SHT_NULL);
1342   // Skip the first, dummy, section.
1343   pshdrs = shdrs + This::shdr_size;
1344   for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1345     {
1346       typename This::Shdr shdr(pshdrs);
1347
1348       // Count the number of sections whose layout will be deferred.
1349       if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1350         ++num_sections_to_defer;
1351
1352       unsigned int sh_type = shdr.get_sh_type();
1353       if (sh_type == elfcpp::SHT_REL || sh_type == elfcpp::SHT_RELA)
1354         {
1355           unsigned int target_shndx = this->adjust_shndx(shdr.get_sh_info());
1356           if (target_shndx == 0 || target_shndx >= shnum)
1357             {
1358               this->error(_("relocation section %u has bad info %u"),
1359                           i, target_shndx);
1360               continue;
1361             }
1362
1363           if (reloc_shndx[target_shndx] != 0)
1364             reloc_shndx[target_shndx] = -1U;
1365           else
1366             {
1367               reloc_shndx[target_shndx] = i;
1368               reloc_type[target_shndx] = sh_type;
1369             }
1370         }
1371     }
1372
1373   Output_sections& out_sections(this->output_sections());
1374   std::vector<Address>& out_section_offsets(this->section_offsets());
1375
1376   if (!is_pass_two)
1377     {
1378       out_sections.resize(shnum);
1379       out_section_offsets.resize(shnum);
1380     }
1381
1382   // If we are only linking for symbols, then there is nothing else to
1383   // do here.
1384   if (this->input_file()->just_symbols())
1385     {
1386       if (!is_pass_two)
1387         {
1388           delete sd->section_headers;
1389           sd->section_headers = NULL;
1390           delete sd->section_names;
1391           sd->section_names = NULL;
1392         }
1393       return;
1394     }
1395
1396   if (num_sections_to_defer > 0)
1397     {
1398       parameters->options().plugins()->add_deferred_layout_object(this);
1399       this->deferred_layout_.reserve(num_sections_to_defer);
1400     }
1401
1402   // Whether we've seen a .note.GNU-stack section.
1403   bool seen_gnu_stack = false;
1404   // The flags of a .note.GNU-stack section.
1405   uint64_t gnu_stack_flags = 0;
1406
1407   // Keep track of which sections to omit.
1408   std::vector<bool> omit(shnum, false);
1409
1410   // Keep track of reloc sections when emitting relocations.
1411   const bool relocatable = parameters->options().relocatable();
1412   const bool emit_relocs = (relocatable
1413                             || parameters->options().emit_relocs());
1414   std::vector<unsigned int> reloc_sections;
1415
1416   // Keep track of .eh_frame sections.
1417   std::vector<unsigned int> eh_frame_sections;
1418
1419   // Keep track of .debug_info and .debug_types sections.
1420   std::vector<unsigned int> debug_info_sections;
1421   std::vector<unsigned int> debug_types_sections;
1422
1423   // Skip the first, dummy, section.
1424   pshdrs = shdrs + This::shdr_size;
1425   for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1426     {
1427       typename This::Shdr shdr(pshdrs);
1428
1429       if (shdr.get_sh_name() >= section_names_size)
1430         {
1431           this->error(_("bad section name offset for section %u: %lu"),
1432                       i, static_cast<unsigned long>(shdr.get_sh_name()));
1433           return;
1434         }
1435
1436       const char* name = pnames + shdr.get_sh_name();
1437
1438       if (!is_pass_two)
1439         {
1440           if (this->handle_gnu_warning_section(name, i, symtab))
1441             {
1442               if (!relocatable && !parameters->options().shared())
1443                 omit[i] = true;
1444             }
1445
1446           // The .note.GNU-stack section is special.  It gives the
1447           // protection flags that this object file requires for the stack
1448           // in memory.
1449           if (strcmp(name, ".note.GNU-stack") == 0)
1450             {
1451               seen_gnu_stack = true;
1452               gnu_stack_flags |= shdr.get_sh_flags();
1453               omit[i] = true;
1454             }
1455
1456           // The .note.GNU-split-stack section is also special.  It
1457           // indicates that the object was compiled with
1458           // -fsplit-stack.
1459           if (this->handle_split_stack_section(name))
1460             {
1461               if (!relocatable && !parameters->options().shared())
1462                 omit[i] = true;
1463             }
1464
1465           // Skip attributes section.
1466           if (parameters->target().is_attributes_section(name))
1467             {
1468               omit[i] = true;
1469             }
1470
1471           bool discard = omit[i];
1472           if (!discard)
1473             {
1474               if (shdr.get_sh_type() == elfcpp::SHT_GROUP)
1475                 {
1476                   if (!this->include_section_group(symtab, layout, i, name,
1477                                                    shdrs, pnames,
1478                                                    section_names_size,
1479                                                    &omit))
1480                     discard = true;
1481                 }
1482               else if ((shdr.get_sh_flags() & elfcpp::SHF_GROUP) == 0
1483                        && Layout::is_linkonce(name))
1484                 {
1485                   if (!this->include_linkonce_section(layout, i, name, shdr))
1486                     discard = true;
1487                 }
1488             }
1489
1490           // Add the section to the incremental inputs layout.
1491           Incremental_inputs* incremental_inputs = layout->incremental_inputs();
1492           if (incremental_inputs != NULL
1493               && !discard
1494               && can_incremental_update(shdr.get_sh_type()))
1495             {
1496               off_t sh_size = shdr.get_sh_size();
1497               section_size_type uncompressed_size;
1498               if (this->section_is_compressed(i, &uncompressed_size))
1499                 sh_size = uncompressed_size;
1500               incremental_inputs->report_input_section(this, i, name, sh_size);
1501             }
1502
1503           if (discard)
1504             {
1505               // Do not include this section in the link.
1506               out_sections[i] = NULL;
1507               out_section_offsets[i] = invalid_address;
1508               continue;
1509             }
1510         }
1511
1512       if (is_pass_one && parameters->options().gc_sections())
1513         {
1514           if (this->is_section_name_included(name)
1515               || layout->keep_input_section (this, name)
1516               || shdr.get_sh_type() == elfcpp::SHT_INIT_ARRAY
1517               || shdr.get_sh_type() == elfcpp::SHT_FINI_ARRAY)
1518             {
1519               symtab->gc()->worklist().push(Section_id(this, i));
1520             }
1521           // If the section name XXX can be represented as a C identifier
1522           // it cannot be discarded if there are references to
1523           // __start_XXX and __stop_XXX symbols.  These need to be
1524           // specially handled.
1525           if (is_cident(name))
1526             {
1527               symtab->gc()->add_cident_section(name, Section_id(this, i));
1528             }
1529         }
1530
1531       // When doing a relocatable link we are going to copy input
1532       // reloc sections into the output.  We only want to copy the
1533       // ones associated with sections which are not being discarded.
1534       // However, we don't know that yet for all sections.  So save
1535       // reloc sections and process them later. Garbage collection is
1536       // not triggered when relocatable code is desired.
1537       if (emit_relocs
1538           && (shdr.get_sh_type() == elfcpp::SHT_REL
1539               || shdr.get_sh_type() == elfcpp::SHT_RELA))
1540         {
1541           reloc_sections.push_back(i);
1542           continue;
1543         }
1544
1545       if (relocatable && shdr.get_sh_type() == elfcpp::SHT_GROUP)
1546         continue;
1547
1548       // The .eh_frame section is special.  It holds exception frame
1549       // information that we need to read in order to generate the
1550       // exception frame header.  We process these after all the other
1551       // sections so that the exception frame reader can reliably
1552       // determine which sections are being discarded, and discard the
1553       // corresponding information.
1554       if (!relocatable
1555           && strcmp(name, ".eh_frame") == 0
1556           && this->check_eh_frame_flags(&shdr))
1557         {
1558           if (is_pass_one)
1559             {
1560               out_sections[i] = reinterpret_cast<Output_section*>(1);
1561               out_section_offsets[i] = invalid_address;
1562             }
1563           else if (should_defer_layout)
1564             this->deferred_layout_.push_back(Deferred_layout(i, name,
1565                                                              pshdrs,
1566                                                              reloc_shndx[i],
1567                                                              reloc_type[i]));
1568           else
1569             eh_frame_sections.push_back(i);
1570           continue;
1571         }
1572
1573       if (is_pass_two && parameters->options().gc_sections())
1574         {
1575           // This is executed during the second pass of garbage
1576           // collection. do_layout has been called before and some
1577           // sections have been already discarded. Simply ignore
1578           // such sections this time around.
1579           if (out_sections[i] == NULL)
1580             {
1581               gold_assert(out_section_offsets[i] == invalid_address);
1582               continue;
1583             }
1584           if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1585               && symtab->gc()->is_section_garbage(this, i))
1586               {
1587                 if (parameters->options().print_gc_sections())
1588                   gold_info(_("%s: removing unused section from '%s'"
1589                               " in file '%s'"),
1590                             program_name, this->section_name(i).c_str(),
1591                             this->name().c_str());
1592                 out_sections[i] = NULL;
1593                 out_section_offsets[i] = invalid_address;
1594                 continue;
1595               }
1596         }
1597
1598       if (is_pass_two && parameters->options().icf_enabled())
1599         {
1600           if (out_sections[i] == NULL)
1601             {
1602               gold_assert(out_section_offsets[i] == invalid_address);
1603               continue;
1604             }
1605           if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1606               && symtab->icf()->is_section_folded(this, i))
1607               {
1608                 if (parameters->options().print_icf_sections())
1609                   {
1610                     Section_id folded =
1611                                 symtab->icf()->get_folded_section(this, i);
1612                     Relobj* folded_obj =
1613                                 reinterpret_cast<Relobj*>(folded.first);
1614                     gold_info(_("%s: ICF folding section '%s' in file '%s'"
1615                                 "into '%s' in file '%s'"),
1616                               program_name, this->section_name(i).c_str(),
1617                               this->name().c_str(),
1618                               folded_obj->section_name(folded.second).c_str(),
1619                               folded_obj->name().c_str());
1620                   }
1621                 out_sections[i] = NULL;
1622                 out_section_offsets[i] = invalid_address;
1623                 continue;
1624               }
1625         }
1626
1627       // Defer layout here if input files are claimed by plugins.  When gc
1628       // is turned on this function is called twice.  For the second call
1629       // should_defer_layout should be false.
1630       if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1631         {
1632           gold_assert(!is_pass_two);
1633           this->deferred_layout_.push_back(Deferred_layout(i, name,
1634                                                            pshdrs,
1635                                                            reloc_shndx[i],
1636                                                            reloc_type[i]));
1637           // Put dummy values here; real values will be supplied by
1638           // do_layout_deferred_sections.
1639           out_sections[i] = reinterpret_cast<Output_section*>(2);
1640           out_section_offsets[i] = invalid_address;
1641           continue;
1642         }
1643
1644       // During gc_pass_two if a section that was previously deferred is
1645       // found, do not layout the section as layout_deferred_sections will
1646       // do it later from gold.cc.
1647       if (is_pass_two
1648           && (out_sections[i] == reinterpret_cast<Output_section*>(2)))
1649         continue;
1650
1651       if (is_pass_one)
1652         {
1653           // This is during garbage collection. The out_sections are
1654           // assigned in the second call to this function.
1655           out_sections[i] = reinterpret_cast<Output_section*>(1);
1656           out_section_offsets[i] = invalid_address;
1657         }
1658       else
1659         {
1660           // When garbage collection is switched on the actual layout
1661           // only happens in the second call.
1662           this->layout_section(layout, i, name, shdr, reloc_shndx[i],
1663                                reloc_type[i]);
1664
1665           // When generating a .gdb_index section, we do additional
1666           // processing of .debug_info and .debug_types sections after all
1667           // the other sections for the same reason as above.
1668           if (!relocatable
1669               && parameters->options().gdb_index()
1670               && !(shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1671             {
1672               if (strcmp(name, ".debug_info") == 0
1673                   || strcmp(name, ".zdebug_info") == 0)
1674                 debug_info_sections.push_back(i);
1675               else if (strcmp(name, ".debug_types") == 0
1676                        || strcmp(name, ".zdebug_types") == 0)
1677                 debug_types_sections.push_back(i);
1678             }
1679         }
1680     }
1681
1682   if (!is_pass_two)
1683     layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags, this);
1684
1685   // When doing a relocatable link handle the reloc sections at the
1686   // end.  Garbage collection  and Identical Code Folding is not
1687   // turned on for relocatable code.
1688   if (emit_relocs)
1689     this->size_relocatable_relocs();
1690
1691   gold_assert(!is_two_pass || reloc_sections.empty());
1692
1693   for (std::vector<unsigned int>::const_iterator p = reloc_sections.begin();
1694        p != reloc_sections.end();
1695        ++p)
1696     {
1697       unsigned int i = *p;
1698       const unsigned char* pshdr;
1699       pshdr = section_headers_data + i * This::shdr_size;
1700       typename This::Shdr shdr(pshdr);
1701
1702       unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1703       if (data_shndx >= shnum)
1704         {
1705           // We already warned about this above.
1706           continue;
1707         }
1708
1709       Output_section* data_section = out_sections[data_shndx];
1710       if (data_section == reinterpret_cast<Output_section*>(2))
1711         {
1712           // The layout for the data section was deferred, so we need
1713           // to defer the relocation section, too.
1714           const char* name = pnames + shdr.get_sh_name();
1715           this->deferred_layout_relocs_.push_back(
1716               Deferred_layout(i, name, pshdr, 0, elfcpp::SHT_NULL));
1717           out_sections[i] = reinterpret_cast<Output_section*>(2);
1718           out_section_offsets[i] = invalid_address;
1719           continue;
1720         }
1721       if (data_section == NULL)
1722         {
1723           out_sections[i] = NULL;
1724           out_section_offsets[i] = invalid_address;
1725           continue;
1726         }
1727
1728       Relocatable_relocs* rr = new Relocatable_relocs();
1729       this->set_relocatable_relocs(i, rr);
1730
1731       Output_section* os = layout->layout_reloc(this, i, shdr, data_section,
1732                                                 rr);
1733       out_sections[i] = os;
1734       out_section_offsets[i] = invalid_address;
1735     }
1736
1737   // Handle the .eh_frame sections at the end.
1738   gold_assert(!is_pass_one || eh_frame_sections.empty());
1739   for (std::vector<unsigned int>::const_iterator p = eh_frame_sections.begin();
1740        p != eh_frame_sections.end();
1741        ++p)
1742     {
1743       unsigned int i = *p;
1744       const unsigned char* pshdr;
1745       pshdr = section_headers_data + i * This::shdr_size;
1746       typename This::Shdr shdr(pshdr);
1747
1748       this->layout_eh_frame_section(layout,
1749                                     symbols_data,
1750                                     symbols_size,
1751                                     symbol_names_data,
1752                                     symbol_names_size,
1753                                     i,
1754                                     shdr,
1755                                     reloc_shndx[i],
1756                                     reloc_type[i]);
1757     }
1758
1759   // When building a .gdb_index section, scan the .debug_info and
1760   // .debug_types sections.
1761   gold_assert(!is_pass_one
1762               || (debug_info_sections.empty() && debug_types_sections.empty()));
1763   for (std::vector<unsigned int>::const_iterator p
1764            = debug_info_sections.begin();
1765        p != debug_info_sections.end();
1766        ++p)
1767     {
1768       unsigned int i = *p;
1769       layout->add_to_gdb_index(false, this, symbols_data, symbols_size,
1770                                i, reloc_shndx[i], reloc_type[i]);
1771     }
1772   for (std::vector<unsigned int>::const_iterator p
1773            = debug_types_sections.begin();
1774        p != debug_types_sections.end();
1775        ++p)
1776     {
1777       unsigned int i = *p;
1778       layout->add_to_gdb_index(true, this, symbols_data, symbols_size,
1779                                i, reloc_shndx[i], reloc_type[i]);
1780     }
1781
1782   if (is_pass_two)
1783     {
1784       delete[] gc_sd->section_headers_data;
1785       delete[] gc_sd->section_names_data;
1786       delete[] gc_sd->symbols_data;
1787       delete[] gc_sd->symbol_names_data;
1788       this->set_symbols_data(NULL);
1789     }
1790   else
1791     {
1792       delete sd->section_headers;
1793       sd->section_headers = NULL;
1794       delete sd->section_names;
1795       sd->section_names = NULL;
1796     }
1797 }
1798
1799 // Layout sections whose layout was deferred while waiting for
1800 // input files from a plugin.
1801
1802 template<int size, bool big_endian>
1803 void
1804 Sized_relobj_file<size, big_endian>::do_layout_deferred_sections(Layout* layout)
1805 {
1806   typename std::vector<Deferred_layout>::iterator deferred;
1807
1808   for (deferred = this->deferred_layout_.begin();
1809        deferred != this->deferred_layout_.end();
1810        ++deferred)
1811     {
1812       typename This::Shdr shdr(deferred->shdr_data_);
1813       // If the section is not included, it is because the garbage collector
1814       // decided it is not needed.  Avoid reverting that decision.
1815       if (!this->is_section_included(deferred->shndx_))
1816         continue;
1817
1818       if (parameters->options().relocatable()
1819           || deferred->name_ != ".eh_frame"
1820           || !this->check_eh_frame_flags(&shdr))
1821         this->layout_section(layout, deferred->shndx_, deferred->name_.c_str(),
1822                              shdr, deferred->reloc_shndx_,
1823                              deferred->reloc_type_);
1824       else
1825         {
1826           // Reading the symbols again here may be slow.
1827           Read_symbols_data sd;
1828           this->read_symbols(&sd);
1829           this->layout_eh_frame_section(layout,
1830                                         sd.symbols->data(),
1831                                         sd.symbols_size,
1832                                         sd.symbol_names->data(),
1833                                         sd.symbol_names_size,
1834                                         deferred->shndx_,
1835                                         shdr,
1836                                         deferred->reloc_shndx_,
1837                                         deferred->reloc_type_);
1838         }
1839     }
1840
1841   this->deferred_layout_.clear();
1842
1843   // Now handle the deferred relocation sections.
1844
1845   Output_sections& out_sections(this->output_sections());
1846   std::vector<Address>& out_section_offsets(this->section_offsets());
1847
1848   for (deferred = this->deferred_layout_relocs_.begin();
1849        deferred != this->deferred_layout_relocs_.end();
1850        ++deferred)
1851     {
1852       unsigned int shndx = deferred->shndx_;
1853       typename This::Shdr shdr(deferred->shdr_data_);
1854       unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1855
1856       Output_section* data_section = out_sections[data_shndx];
1857       if (data_section == NULL)
1858         {
1859           out_sections[shndx] = NULL;
1860           out_section_offsets[shndx] = invalid_address;
1861           continue;
1862         }
1863
1864       Relocatable_relocs* rr = new Relocatable_relocs();
1865       this->set_relocatable_relocs(shndx, rr);
1866
1867       Output_section* os = layout->layout_reloc(this, shndx, shdr,
1868                                                 data_section, rr);
1869       out_sections[shndx] = os;
1870       out_section_offsets[shndx] = invalid_address;
1871     }
1872 }
1873
1874 // Add the symbols to the symbol table.
1875
1876 template<int size, bool big_endian>
1877 void
1878 Sized_relobj_file<size, big_endian>::do_add_symbols(Symbol_table* symtab,
1879                                                     Read_symbols_data* sd,
1880                                                     Layout*)
1881 {
1882   if (sd->symbols == NULL)
1883     {
1884       gold_assert(sd->symbol_names == NULL);
1885       return;
1886     }
1887
1888   const int sym_size = This::sym_size;
1889   size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1890                      / sym_size);
1891   if (symcount * sym_size != sd->symbols_size - sd->external_symbols_offset)
1892     {
1893       this->error(_("size of symbols is not multiple of symbol size"));
1894       return;
1895     }
1896
1897   this->symbols_.resize(symcount);
1898
1899   const char* sym_names =
1900     reinterpret_cast<const char*>(sd->symbol_names->data());
1901   symtab->add_from_relobj(this,
1902                           sd->symbols->data() + sd->external_symbols_offset,
1903                           symcount, this->local_symbol_count_,
1904                           sym_names, sd->symbol_names_size,
1905                           &this->symbols_,
1906                           &this->defined_count_);
1907
1908   delete sd->symbols;
1909   sd->symbols = NULL;
1910   delete sd->symbol_names;
1911   sd->symbol_names = NULL;
1912 }
1913
1914 // Find out if this object, that is a member of a lib group, should be included
1915 // in the link. We check every symbol defined by this object. If the symbol
1916 // table has a strong undefined reference to that symbol, we have to include
1917 // the object.
1918
1919 template<int size, bool big_endian>
1920 Archive::Should_include
1921 Sized_relobj_file<size, big_endian>::do_should_include_member(
1922     Symbol_table* symtab,
1923     Layout* layout,
1924     Read_symbols_data* sd,
1925     std::string* why)
1926 {
1927   char* tmpbuf = NULL;
1928   size_t tmpbuflen = 0;
1929   const char* sym_names =
1930       reinterpret_cast<const char*>(sd->symbol_names->data());
1931   const unsigned char* syms =
1932       sd->symbols->data() + sd->external_symbols_offset;
1933   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1934   size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1935                          / sym_size);
1936
1937   const unsigned char* p = syms;
1938
1939   for (size_t i = 0; i < symcount; ++i, p += sym_size)
1940     {
1941       elfcpp::Sym<size, big_endian> sym(p);
1942       unsigned int st_shndx = sym.get_st_shndx();
1943       if (st_shndx == elfcpp::SHN_UNDEF)
1944         continue;
1945
1946       unsigned int st_name = sym.get_st_name();
1947       const char* name = sym_names + st_name;
1948       Symbol* symbol;
1949       Archive::Should_include t = Archive::should_include_member(symtab,
1950                                                                  layout,
1951                                                                  name,
1952                                                                  &symbol, why,
1953                                                                  &tmpbuf,
1954                                                                  &tmpbuflen);
1955       if (t == Archive::SHOULD_INCLUDE_YES)
1956         {
1957           if (tmpbuf != NULL)
1958             free(tmpbuf);
1959           return t;
1960         }
1961     }
1962   if (tmpbuf != NULL)
1963     free(tmpbuf);
1964   return Archive::SHOULD_INCLUDE_UNKNOWN;
1965 }
1966
1967 // Iterate over global defined symbols, calling a visitor class V for each.
1968
1969 template<int size, bool big_endian>
1970 void
1971 Sized_relobj_file<size, big_endian>::do_for_all_global_symbols(
1972     Read_symbols_data* sd,
1973     Library_base::Symbol_visitor_base* v)
1974 {
1975   const char* sym_names =
1976       reinterpret_cast<const char*>(sd->symbol_names->data());
1977   const unsigned char* syms =
1978       sd->symbols->data() + sd->external_symbols_offset;
1979   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1980   size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1981                      / sym_size);
1982   const unsigned char* p = syms;
1983
1984   for (size_t i = 0; i < symcount; ++i, p += sym_size)
1985     {
1986       elfcpp::Sym<size, big_endian> sym(p);
1987       if (sym.get_st_shndx() != elfcpp::SHN_UNDEF)
1988         v->visit(sym_names + sym.get_st_name());
1989     }
1990 }
1991
1992 // Return whether the local symbol SYMNDX has a PLT offset.
1993
1994 template<int size, bool big_endian>
1995 bool
1996 Sized_relobj_file<size, big_endian>::local_has_plt_offset(
1997     unsigned int symndx) const
1998 {
1999   typename Local_plt_offsets::const_iterator p =
2000     this->local_plt_offsets_.find(symndx);
2001   return p != this->local_plt_offsets_.end();
2002 }
2003
2004 // Get the PLT offset of a local symbol.
2005
2006 template<int size, bool big_endian>
2007 unsigned int
2008 Sized_relobj_file<size, big_endian>::do_local_plt_offset(
2009     unsigned int symndx) const
2010 {
2011   typename Local_plt_offsets::const_iterator p =
2012     this->local_plt_offsets_.find(symndx);
2013   gold_assert(p != this->local_plt_offsets_.end());
2014   return p->second;
2015 }
2016
2017 // Set the PLT offset of a local symbol.
2018
2019 template<int size, bool big_endian>
2020 void
2021 Sized_relobj_file<size, big_endian>::set_local_plt_offset(
2022     unsigned int symndx, unsigned int plt_offset)
2023 {
2024   std::pair<typename Local_plt_offsets::iterator, bool> ins =
2025     this->local_plt_offsets_.insert(std::make_pair(symndx, plt_offset));
2026   gold_assert(ins.second);
2027 }
2028
2029 // First pass over the local symbols.  Here we add their names to
2030 // *POOL and *DYNPOOL, and we store the symbol value in
2031 // THIS->LOCAL_VALUES_.  This function is always called from a
2032 // singleton thread.  This is followed by a call to
2033 // finalize_local_symbols.
2034
2035 template<int size, bool big_endian>
2036 void
2037 Sized_relobj_file<size, big_endian>::do_count_local_symbols(Stringpool* pool,
2038                                                             Stringpool* dynpool)
2039 {
2040   gold_assert(this->symtab_shndx_ != -1U);
2041   if (this->symtab_shndx_ == 0)
2042     {
2043       // This object has no symbols.  Weird but legal.
2044       return;
2045     }
2046
2047   // Read the symbol table section header.
2048   const unsigned int symtab_shndx = this->symtab_shndx_;
2049   typename This::Shdr symtabshdr(this,
2050                                  this->elf_file_.section_header(symtab_shndx));
2051   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
2052
2053   // Read the local symbols.
2054   const int sym_size = This::sym_size;
2055   const unsigned int loccount = this->local_symbol_count_;
2056   gold_assert(loccount == symtabshdr.get_sh_info());
2057   off_t locsize = loccount * sym_size;
2058   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
2059                                               locsize, true, true);
2060
2061   // Read the symbol names.
2062   const unsigned int strtab_shndx =
2063     this->adjust_shndx(symtabshdr.get_sh_link());
2064   section_size_type strtab_size;
2065   const unsigned char* pnamesu = this->section_contents(strtab_shndx,
2066                                                         &strtab_size,
2067                                                         true);
2068   const char* pnames = reinterpret_cast<const char*>(pnamesu);
2069
2070   // Loop over the local symbols.
2071
2072   const Output_sections& out_sections(this->output_sections());
2073   unsigned int shnum = this->shnum();
2074   unsigned int count = 0;
2075   unsigned int dyncount = 0;
2076   // Skip the first, dummy, symbol.
2077   psyms += sym_size;
2078   bool strip_all = parameters->options().strip_all();
2079   bool discard_all = parameters->options().discard_all();
2080   bool discard_locals = parameters->options().discard_locals();
2081   for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
2082     {
2083       elfcpp::Sym<size, big_endian> sym(psyms);
2084
2085       Symbol_value<size>& lv(this->local_values_[i]);
2086
2087       bool is_ordinary;
2088       unsigned int shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
2089                                                   &is_ordinary);
2090       lv.set_input_shndx(shndx, is_ordinary);
2091
2092       if (sym.get_st_type() == elfcpp::STT_SECTION)
2093         lv.set_is_section_symbol();
2094       else if (sym.get_st_type() == elfcpp::STT_TLS)
2095         lv.set_is_tls_symbol();
2096       else if (sym.get_st_type() == elfcpp::STT_GNU_IFUNC)
2097         lv.set_is_ifunc_symbol();
2098
2099       // Save the input symbol value for use in do_finalize_local_symbols().
2100       lv.set_input_value(sym.get_st_value());
2101
2102       // Decide whether this symbol should go into the output file.
2103
2104       if ((shndx < shnum && out_sections[shndx] == NULL)
2105           || shndx == this->discarded_eh_frame_shndx_)
2106         {
2107           lv.set_no_output_symtab_entry();
2108           gold_assert(!lv.needs_output_dynsym_entry());
2109           continue;
2110         }
2111
2112       if (sym.get_st_type() == elfcpp::STT_SECTION)
2113         {
2114           lv.set_no_output_symtab_entry();
2115           gold_assert(!lv.needs_output_dynsym_entry());
2116           continue;
2117         }
2118
2119       if (sym.get_st_name() >= strtab_size)
2120         {
2121           this->error(_("local symbol %u section name out of range: %u >= %u"),
2122                       i, sym.get_st_name(),
2123                       static_cast<unsigned int>(strtab_size));
2124           lv.set_no_output_symtab_entry();
2125           continue;
2126         }
2127
2128       const char* name = pnames + sym.get_st_name();
2129
2130       // If needed, add the symbol to the dynamic symbol table string pool.
2131       if (lv.needs_output_dynsym_entry())
2132         {
2133           dynpool->add(name, true, NULL);
2134           ++dyncount;
2135         }
2136
2137       if (strip_all
2138           || (discard_all && lv.may_be_discarded_from_output_symtab()))
2139         {
2140           lv.set_no_output_symtab_entry();
2141           continue;
2142         }
2143
2144       // If --discard-locals option is used, discard all temporary local
2145       // symbols.  These symbols start with system-specific local label
2146       // prefixes, typically .L for ELF system.  We want to be compatible
2147       // with GNU ld so here we essentially use the same check in
2148       // bfd_is_local_label().  The code is different because we already
2149       // know that:
2150       //
2151       //   - the symbol is local and thus cannot have global or weak binding.
2152       //   - the symbol is not a section symbol.
2153       //   - the symbol has a name.
2154       //
2155       // We do not discard a symbol if it needs a dynamic symbol entry.
2156       if (discard_locals
2157           && sym.get_st_type() != elfcpp::STT_FILE
2158           && !lv.needs_output_dynsym_entry()
2159           && lv.may_be_discarded_from_output_symtab()
2160           && parameters->target().is_local_label_name(name))
2161         {
2162           lv.set_no_output_symtab_entry();
2163           continue;
2164         }
2165
2166       // Discard the local symbol if -retain_symbols_file is specified
2167       // and the local symbol is not in that file.
2168       if (!parameters->options().should_retain_symbol(name))
2169         {
2170           lv.set_no_output_symtab_entry();
2171           continue;
2172         }
2173
2174       // Add the symbol to the symbol table string pool.
2175       pool->add(name, true, NULL);
2176       ++count;
2177     }
2178
2179   this->output_local_symbol_count_ = count;
2180   this->output_local_dynsym_count_ = dyncount;
2181 }
2182
2183 // Compute the final value of a local symbol.
2184
2185 template<int size, bool big_endian>
2186 typename Sized_relobj_file<size, big_endian>::Compute_final_local_value_status
2187 Sized_relobj_file<size, big_endian>::compute_final_local_value_internal(
2188     unsigned int r_sym,
2189     const Symbol_value<size>* lv_in,
2190     Symbol_value<size>* lv_out,
2191     bool relocatable,
2192     const Output_sections& out_sections,
2193     const std::vector<Address>& out_offsets,
2194     const Symbol_table* symtab)
2195 {
2196   // We are going to overwrite *LV_OUT, if it has a merged symbol value,
2197   // we may have a memory leak.
2198   gold_assert(lv_out->has_output_value());
2199
2200   bool is_ordinary;
2201   unsigned int shndx = lv_in->input_shndx(&is_ordinary);
2202
2203   // Set the output symbol value.
2204
2205   if (!is_ordinary)
2206     {
2207       if (shndx == elfcpp::SHN_ABS || Symbol::is_common_shndx(shndx))
2208         lv_out->set_output_value(lv_in->input_value());
2209       else
2210         {
2211           this->error(_("unknown section index %u for local symbol %u"),
2212                       shndx, r_sym);
2213           lv_out->set_output_value(0);
2214           return This::CFLV_ERROR;
2215         }
2216     }
2217   else
2218     {
2219       if (shndx >= this->shnum())
2220         {
2221           this->error(_("local symbol %u section index %u out of range"),
2222                       r_sym, shndx);
2223           lv_out->set_output_value(0);
2224           return This::CFLV_ERROR;
2225         }
2226
2227       Output_section* os = out_sections[shndx];
2228       Address secoffset = out_offsets[shndx];
2229       if (symtab->is_section_folded(this, shndx))
2230         {
2231           gold_assert(os == NULL && secoffset == invalid_address);
2232           // Get the os of the section it is folded onto.
2233           Section_id folded = symtab->icf()->get_folded_section(this,
2234                                                                 shndx);
2235           gold_assert(folded.first != NULL);
2236           Sized_relobj_file<size, big_endian>* folded_obj = reinterpret_cast
2237             <Sized_relobj_file<size, big_endian>*>(folded.first);
2238           os = folded_obj->output_section(folded.second);
2239           gold_assert(os != NULL);
2240           secoffset = folded_obj->get_output_section_offset(folded.second);
2241
2242           // This could be a relaxed input section.
2243           if (secoffset == invalid_address)
2244             {
2245               const Output_relaxed_input_section* relaxed_section =
2246                 os->find_relaxed_input_section(folded_obj, folded.second);
2247               gold_assert(relaxed_section != NULL);
2248               secoffset = relaxed_section->address() - os->address();
2249             }
2250         }
2251
2252       if (os == NULL)
2253         {
2254           // This local symbol belongs to a section we are discarding.
2255           // In some cases when applying relocations later, we will
2256           // attempt to match it to the corresponding kept section,
2257           // so we leave the input value unchanged here.
2258           return This::CFLV_DISCARDED;
2259         }
2260       else if (secoffset == invalid_address)
2261         {
2262           uint64_t start;
2263
2264           // This is a SHF_MERGE section or one which otherwise
2265           // requires special handling.
2266           if (shndx == this->discarded_eh_frame_shndx_)
2267             {
2268               // This local symbol belongs to a discarded .eh_frame
2269               // section.  Just treat it like the case in which
2270               // os == NULL above.
2271               gold_assert(this->has_eh_frame_);
2272               return This::CFLV_DISCARDED;
2273             }
2274           else if (!lv_in->is_section_symbol())
2275             {
2276               // This is not a section symbol.  We can determine
2277               // the final value now.
2278               lv_out->set_output_value(
2279                   os->output_address(this, shndx, lv_in->input_value()));
2280             }
2281           else if (!os->find_starting_output_address(this, shndx, &start))
2282             {
2283               // This is a section symbol, but apparently not one in a
2284               // merged section.  First check to see if this is a relaxed
2285               // input section.  If so, use its address.  Otherwise just
2286               // use the start of the output section.  This happens with
2287               // relocatable links when the input object has section
2288               // symbols for arbitrary non-merge sections.
2289               const Output_section_data* posd =
2290                 os->find_relaxed_input_section(this, shndx);
2291               if (posd != NULL)
2292                 {
2293                   Address relocatable_link_adjustment =
2294                     relocatable ? os->address() : 0;
2295                   lv_out->set_output_value(posd->address()
2296                                            - relocatable_link_adjustment);
2297                 }
2298               else
2299                 lv_out->set_output_value(os->address());
2300             }
2301           else
2302             {
2303               // We have to consider the addend to determine the
2304               // value to use in a relocation.  START is the start
2305               // of this input section.  If we are doing a relocatable
2306               // link, use offset from start output section instead of
2307               // address.
2308               Address adjusted_start =
2309                 relocatable ? start - os->address() : start;
2310               Merged_symbol_value<size>* msv =
2311                 new Merged_symbol_value<size>(lv_in->input_value(),
2312                                               adjusted_start);
2313               lv_out->set_merged_symbol_value(msv);
2314             }
2315         }
2316       else if (lv_in->is_tls_symbol())
2317         lv_out->set_output_value(os->tls_offset()
2318                                  + secoffset
2319                                  + lv_in->input_value());
2320       else
2321         lv_out->set_output_value((relocatable ? 0 : os->address())
2322                                  + secoffset
2323                                  + lv_in->input_value());
2324     }
2325   return This::CFLV_OK;
2326 }
2327
2328 // Compute final local symbol value.  R_SYM is the index of a local
2329 // symbol in symbol table.  LV points to a symbol value, which is
2330 // expected to hold the input value and to be over-written by the
2331 // final value.  SYMTAB points to a symbol table.  Some targets may want
2332 // to know would-be-finalized local symbol values in relaxation.
2333 // Hence we provide this method.  Since this method updates *LV, a
2334 // callee should make a copy of the original local symbol value and
2335 // use the copy instead of modifying an object's local symbols before
2336 // everything is finalized.  The caller should also free up any allocated
2337 // memory in the return value in *LV.
2338 template<int size, bool big_endian>
2339 typename Sized_relobj_file<size, big_endian>::Compute_final_local_value_status
2340 Sized_relobj_file<size, big_endian>::compute_final_local_value(
2341     unsigned int r_sym,
2342     const Symbol_value<size>* lv_in,
2343     Symbol_value<size>* lv_out,
2344     const Symbol_table* symtab)
2345 {
2346   // This is just a wrapper of compute_final_local_value_internal.
2347   const bool relocatable = parameters->options().relocatable();
2348   const Output_sections& out_sections(this->output_sections());
2349   const std::vector<Address>& out_offsets(this->section_offsets());
2350   return this->compute_final_local_value_internal(r_sym, lv_in, lv_out,
2351                                                   relocatable, out_sections,
2352                                                   out_offsets, symtab);
2353 }
2354
2355 // Finalize the local symbols.  Here we set the final value in
2356 // THIS->LOCAL_VALUES_ and set their output symbol table indexes.
2357 // This function is always called from a singleton thread.  The actual
2358 // output of the local symbols will occur in a separate task.
2359
2360 template<int size, bool big_endian>
2361 unsigned int
2362 Sized_relobj_file<size, big_endian>::do_finalize_local_symbols(
2363     unsigned int index,
2364     off_t off,
2365     Symbol_table* symtab)
2366 {
2367   gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
2368
2369   const unsigned int loccount = this->local_symbol_count_;
2370   this->local_symbol_offset_ = off;
2371
2372   const bool relocatable = parameters->options().relocatable();
2373   const Output_sections& out_sections(this->output_sections());
2374   const std::vector<Address>& out_offsets(this->section_offsets());
2375
2376   for (unsigned int i = 1; i < loccount; ++i)
2377     {
2378       Symbol_value<size>* lv = &this->local_values_[i];
2379
2380       Compute_final_local_value_status cflv_status =
2381         this->compute_final_local_value_internal(i, lv, lv, relocatable,
2382                                                  out_sections, out_offsets,
2383                                                  symtab);
2384       switch (cflv_status)
2385         {
2386         case CFLV_OK:
2387           if (!lv->is_output_symtab_index_set())
2388             {
2389               lv->set_output_symtab_index(index);
2390               ++index;
2391             }
2392           break;
2393         case CFLV_DISCARDED:
2394         case CFLV_ERROR:
2395           // Do nothing.
2396           break;
2397         default:
2398           gold_unreachable();
2399         }
2400     }
2401   return index;
2402 }
2403
2404 // Set the output dynamic symbol table indexes for the local variables.
2405
2406 template<int size, bool big_endian>
2407 unsigned int
2408 Sized_relobj_file<size, big_endian>::do_set_local_dynsym_indexes(
2409     unsigned int index)
2410 {
2411   const unsigned int loccount = this->local_symbol_count_;
2412   for (unsigned int i = 1; i < loccount; ++i)
2413     {
2414       Symbol_value<size>& lv(this->local_values_[i]);
2415       if (lv.needs_output_dynsym_entry())
2416         {
2417           lv.set_output_dynsym_index(index);
2418           ++index;
2419         }
2420     }
2421   return index;
2422 }
2423
2424 // Set the offset where local dynamic symbol information will be stored.
2425 // Returns the count of local symbols contributed to the symbol table by
2426 // this object.
2427
2428 template<int size, bool big_endian>
2429 unsigned int
2430 Sized_relobj_file<size, big_endian>::do_set_local_dynsym_offset(off_t off)
2431 {
2432   gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
2433   this->local_dynsym_offset_ = off;
2434   return this->output_local_dynsym_count_;
2435 }
2436
2437 // If Symbols_data is not NULL get the section flags from here otherwise
2438 // get it from the file.
2439
2440 template<int size, bool big_endian>
2441 uint64_t
2442 Sized_relobj_file<size, big_endian>::do_section_flags(unsigned int shndx)
2443 {
2444   Symbols_data* sd = this->get_symbols_data();
2445   if (sd != NULL)
2446     {
2447       const unsigned char* pshdrs = sd->section_headers_data
2448                                     + This::shdr_size * shndx;
2449       typename This::Shdr shdr(pshdrs);
2450       return shdr.get_sh_flags();
2451     }
2452   // If sd is NULL, read the section header from the file.
2453   return this->elf_file_.section_flags(shndx);
2454 }
2455
2456 // Get the section's ent size from Symbols_data.  Called by get_section_contents
2457 // in icf.cc
2458
2459 template<int size, bool big_endian>
2460 uint64_t
2461 Sized_relobj_file<size, big_endian>::do_section_entsize(unsigned int shndx)
2462 {
2463   Symbols_data* sd = this->get_symbols_data();
2464   gold_assert(sd != NULL);
2465
2466   const unsigned char* pshdrs = sd->section_headers_data
2467                                 + This::shdr_size * shndx;
2468   typename This::Shdr shdr(pshdrs);
2469   return shdr.get_sh_entsize();
2470 }
2471
2472 // Write out the local symbols.
2473
2474 template<int size, bool big_endian>
2475 void
2476 Sized_relobj_file<size, big_endian>::write_local_symbols(
2477     Output_file* of,
2478     const Stringpool* sympool,
2479     const Stringpool* dynpool,
2480     Output_symtab_xindex* symtab_xindex,
2481     Output_symtab_xindex* dynsym_xindex,
2482     off_t symtab_off)
2483 {
2484   const bool strip_all = parameters->options().strip_all();
2485   if (strip_all)
2486     {
2487       if (this->output_local_dynsym_count_ == 0)
2488         return;
2489       this->output_local_symbol_count_ = 0;
2490     }
2491
2492   gold_assert(this->symtab_shndx_ != -1U);
2493   if (this->symtab_shndx_ == 0)
2494     {
2495       // This object has no symbols.  Weird but legal.
2496       return;
2497     }
2498
2499   // Read the symbol table section header.
2500   const unsigned int symtab_shndx = this->symtab_shndx_;
2501   typename This::Shdr symtabshdr(this,
2502                                  this->elf_file_.section_header(symtab_shndx));
2503   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
2504   const unsigned int loccount = this->local_symbol_count_;
2505   gold_assert(loccount == symtabshdr.get_sh_info());
2506
2507   // Read the local symbols.
2508   const int sym_size = This::sym_size;
2509   off_t locsize = loccount * sym_size;
2510   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
2511                                               locsize, true, false);
2512
2513   // Read the symbol names.
2514   const unsigned int strtab_shndx =
2515     this->adjust_shndx(symtabshdr.get_sh_link());
2516   section_size_type strtab_size;
2517   const unsigned char* pnamesu = this->section_contents(strtab_shndx,
2518                                                         &strtab_size,
2519                                                         false);
2520   const char* pnames = reinterpret_cast<const char*>(pnamesu);
2521
2522   // Get views into the output file for the portions of the symbol table
2523   // and the dynamic symbol table that we will be writing.
2524   off_t output_size = this->output_local_symbol_count_ * sym_size;
2525   unsigned char* oview = NULL;
2526   if (output_size > 0)
2527     oview = of->get_output_view(symtab_off + this->local_symbol_offset_,
2528                                 output_size);
2529
2530   off_t dyn_output_size = this->output_local_dynsym_count_ * sym_size;
2531   unsigned char* dyn_oview = NULL;
2532   if (dyn_output_size > 0)
2533     dyn_oview = of->get_output_view(this->local_dynsym_offset_,
2534                                     dyn_output_size);
2535
2536   const Output_sections out_sections(this->output_sections());
2537
2538   gold_assert(this->local_values_.size() == loccount);
2539
2540   unsigned char* ov = oview;
2541   unsigned char* dyn_ov = dyn_oview;
2542   psyms += sym_size;
2543   for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
2544     {
2545       elfcpp::Sym<size, big_endian> isym(psyms);
2546
2547       Symbol_value<size>& lv(this->local_values_[i]);
2548
2549       bool is_ordinary;
2550       unsigned int st_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
2551                                                      &is_ordinary);
2552       if (is_ordinary)
2553         {
2554           gold_assert(st_shndx < out_sections.size());
2555           if (out_sections[st_shndx] == NULL)
2556             continue;
2557           st_shndx = out_sections[st_shndx]->out_shndx();
2558           if (st_shndx >= elfcpp::SHN_LORESERVE)
2559             {
2560               if (lv.has_output_symtab_entry())
2561                 symtab_xindex->add(lv.output_symtab_index(), st_shndx);
2562               if (lv.has_output_dynsym_entry())
2563                 dynsym_xindex->add(lv.output_dynsym_index(), st_shndx);
2564               st_shndx = elfcpp::SHN_XINDEX;
2565             }
2566         }
2567
2568       // Write the symbol to the output symbol table.
2569       if (lv.has_output_symtab_entry())
2570         {
2571           elfcpp::Sym_write<size, big_endian> osym(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(sympool->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           ov += sym_size;
2583         }
2584
2585       // Write the symbol to the output dynamic symbol table.
2586       if (lv.has_output_dynsym_entry())
2587         {
2588           gold_assert(dyn_ov < dyn_oview + dyn_output_size);
2589           elfcpp::Sym_write<size, big_endian> osym(dyn_ov);
2590
2591           gold_assert(isym.get_st_name() < strtab_size);
2592           const char* name = pnames + isym.get_st_name();
2593           osym.put_st_name(dynpool->get_offset(name));
2594           osym.put_st_value(this->local_values_[i].value(this, 0));
2595           osym.put_st_size(isym.get_st_size());
2596           osym.put_st_info(isym.get_st_info());
2597           osym.put_st_other(isym.get_st_other());
2598           osym.put_st_shndx(st_shndx);
2599
2600           dyn_ov += sym_size;
2601         }
2602     }
2603
2604
2605   if (output_size > 0)
2606     {
2607       gold_assert(ov - oview == output_size);
2608       of->write_output_view(symtab_off + this->local_symbol_offset_,
2609                             output_size, oview);
2610     }
2611
2612   if (dyn_output_size > 0)
2613     {
2614       gold_assert(dyn_ov - dyn_oview == dyn_output_size);
2615       of->write_output_view(this->local_dynsym_offset_, dyn_output_size,
2616                             dyn_oview);
2617     }
2618 }
2619
2620 // Set *INFO to symbolic information about the offset OFFSET in the
2621 // section SHNDX.  Return true if we found something, false if we
2622 // found nothing.
2623
2624 template<int size, bool big_endian>
2625 bool
2626 Sized_relobj_file<size, big_endian>::get_symbol_location_info(
2627     unsigned int shndx,
2628     off_t offset,
2629     Symbol_location_info* info)
2630 {
2631   if (this->symtab_shndx_ == 0)
2632     return false;
2633
2634   section_size_type symbols_size;
2635   const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
2636                                                         &symbols_size,
2637                                                         false);
2638
2639   unsigned int symbol_names_shndx =
2640     this->adjust_shndx(this->section_link(this->symtab_shndx_));
2641   section_size_type names_size;
2642   const unsigned char* symbol_names_u =
2643     this->section_contents(symbol_names_shndx, &names_size, false);
2644   const char* symbol_names = reinterpret_cast<const char*>(symbol_names_u);
2645
2646   const int sym_size = This::sym_size;
2647   const size_t count = symbols_size / sym_size;
2648
2649   const unsigned char* p = symbols;
2650   for (size_t i = 0; i < count; ++i, p += sym_size)
2651     {
2652       elfcpp::Sym<size, big_endian> sym(p);
2653
2654       if (sym.get_st_type() == elfcpp::STT_FILE)
2655         {
2656           if (sym.get_st_name() >= names_size)
2657             info->source_file = "(invalid)";
2658           else
2659             info->source_file = symbol_names + sym.get_st_name();
2660           continue;
2661         }
2662
2663       bool is_ordinary;
2664       unsigned int st_shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
2665                                                      &is_ordinary);
2666       if (is_ordinary
2667           && st_shndx == shndx
2668           && static_cast<off_t>(sym.get_st_value()) <= offset
2669           && (static_cast<off_t>(sym.get_st_value() + sym.get_st_size())
2670               > offset))
2671         {
2672           if (sym.get_st_name() > names_size)
2673             info->enclosing_symbol_name = "(invalid)";
2674           else
2675             {
2676               info->enclosing_symbol_name = symbol_names + sym.get_st_name();
2677               if (parameters->options().do_demangle())
2678                 {
2679                   char* demangled_name = cplus_demangle(
2680                       info->enclosing_symbol_name.c_str(),
2681                       DMGL_ANSI | DMGL_PARAMS);
2682                   if (demangled_name != NULL)
2683                     {
2684                       info->enclosing_symbol_name.assign(demangled_name);
2685                       free(demangled_name);
2686                     }
2687                 }
2688             }
2689           return true;
2690         }
2691     }
2692
2693   return false;
2694 }
2695
2696 // Look for a kept section corresponding to the given discarded section,
2697 // and return its output address.  This is used only for relocations in
2698 // debugging sections.  If we can't find the kept section, return 0.
2699
2700 template<int size, bool big_endian>
2701 typename Sized_relobj_file<size, big_endian>::Address
2702 Sized_relobj_file<size, big_endian>::map_to_kept_section(
2703     unsigned int shndx,
2704     bool* found) const
2705 {
2706   Relobj* kept_object;
2707   unsigned int kept_shndx;
2708   if (this->get_kept_comdat_section(shndx, &kept_object, &kept_shndx))
2709     {
2710       Sized_relobj_file<size, big_endian>* kept_relobj =
2711         static_cast<Sized_relobj_file<size, big_endian>*>(kept_object);
2712       Output_section* os = kept_relobj->output_section(kept_shndx);
2713       Address offset = kept_relobj->get_output_section_offset(kept_shndx);
2714       if (os != NULL && offset != invalid_address)
2715         {
2716           *found = true;
2717           return os->address() + offset;
2718         }
2719     }
2720   *found = false;
2721   return 0;
2722 }
2723
2724 // Get symbol counts.
2725
2726 template<int size, bool big_endian>
2727 void
2728 Sized_relobj_file<size, big_endian>::do_get_global_symbol_counts(
2729     const Symbol_table*,
2730     size_t* defined,
2731     size_t* used) const
2732 {
2733   *defined = this->defined_count_;
2734   size_t count = 0;
2735   for (typename Symbols::const_iterator p = this->symbols_.begin();
2736        p != this->symbols_.end();
2737        ++p)
2738     if (*p != NULL
2739         && (*p)->source() == Symbol::FROM_OBJECT
2740         && (*p)->object() == this
2741         && (*p)->is_defined())
2742       ++count;
2743   *used = count;
2744 }
2745
2746 // Return a view of the decompressed contents of a section.  Set *PLEN
2747 // to the size.  Set *IS_NEW to true if the contents need to be freed
2748 // by the caller.
2749
2750 template<int size, bool big_endian>
2751 const unsigned char*
2752 Sized_relobj_file<size, big_endian>::do_decompressed_section_contents(
2753     unsigned int shndx,
2754     section_size_type* plen,
2755     bool* is_new)
2756 {
2757   section_size_type buffer_size;
2758   const unsigned char* buffer = this->do_section_contents(shndx, &buffer_size,
2759                                                           false);
2760
2761   if (this->compressed_sections_ == NULL)
2762     {
2763       *plen = buffer_size;
2764       *is_new = false;
2765       return buffer;
2766     }
2767
2768   Compressed_section_map::const_iterator p =
2769       this->compressed_sections_->find(shndx);
2770   if (p == this->compressed_sections_->end())
2771     {
2772       *plen = buffer_size;
2773       *is_new = false;
2774       return buffer;
2775     }
2776
2777   section_size_type uncompressed_size = p->second.size;
2778   if (p->second.contents != NULL)
2779     {
2780       *plen = uncompressed_size;
2781       *is_new = false;
2782       return p->second.contents;
2783     }
2784
2785   unsigned char* uncompressed_data = new unsigned char[uncompressed_size];
2786   if (!decompress_input_section(buffer,
2787                                 buffer_size,
2788                                 uncompressed_data,
2789                                 uncompressed_size))
2790     this->error(_("could not decompress section %s"),
2791                 this->do_section_name(shndx).c_str());
2792
2793   // We could cache the results in p->second.contents and store
2794   // false in *IS_NEW, but build_compressed_section_map() would
2795   // have done so if it had expected it to be profitable.  If
2796   // we reach this point, we expect to need the contents only
2797   // once in this pass.
2798   *plen = uncompressed_size;
2799   *is_new = true;
2800   return uncompressed_data;
2801 }
2802
2803 // Discard any buffers of uncompressed sections.  This is done
2804 // at the end of the Add_symbols task.
2805
2806 template<int size, bool big_endian>
2807 void
2808 Sized_relobj_file<size, big_endian>::do_discard_decompressed_sections()
2809 {
2810   if (this->compressed_sections_ == NULL)
2811     return;
2812
2813   for (Compressed_section_map::iterator p = this->compressed_sections_->begin();
2814        p != this->compressed_sections_->end();
2815        ++p)
2816     {
2817       if (p->second.contents != NULL)
2818         {
2819           delete[] p->second.contents;
2820           p->second.contents = NULL;
2821         }
2822     }
2823 }
2824
2825 // Input_objects methods.
2826
2827 // Add a regular relocatable object to the list.  Return false if this
2828 // object should be ignored.
2829
2830 bool
2831 Input_objects::add_object(Object* obj)
2832 {
2833   // Print the filename if the -t/--trace option is selected.
2834   if (parameters->options().trace())
2835     gold_info("%s", obj->name().c_str());
2836
2837   if (!obj->is_dynamic())
2838     this->relobj_list_.push_back(static_cast<Relobj*>(obj));
2839   else
2840     {
2841       // See if this is a duplicate SONAME.
2842       Dynobj* dynobj = static_cast<Dynobj*>(obj);
2843       const char* soname = dynobj->soname();
2844
2845       std::pair<Unordered_set<std::string>::iterator, bool> ins =
2846         this->sonames_.insert(soname);
2847       if (!ins.second)
2848         {
2849           // We have already seen a dynamic object with this soname.
2850           return false;
2851         }
2852
2853       this->dynobj_list_.push_back(dynobj);
2854     }
2855
2856   // Add this object to the cross-referencer if requested.
2857   if (parameters->options().user_set_print_symbol_counts()
2858       || parameters->options().cref())
2859     {
2860       if (this->cref_ == NULL)
2861         this->cref_ = new Cref();
2862       this->cref_->add_object(obj);
2863     }
2864
2865   return true;
2866 }
2867
2868 // For each dynamic object, record whether we've seen all of its
2869 // explicit dependencies.
2870
2871 void
2872 Input_objects::check_dynamic_dependencies() const
2873 {
2874   bool issued_copy_dt_needed_error = false;
2875   for (Dynobj_list::const_iterator p = this->dynobj_list_.begin();
2876        p != this->dynobj_list_.end();
2877        ++p)
2878     {
2879       const Dynobj::Needed& needed((*p)->needed());
2880       bool found_all = true;
2881       Dynobj::Needed::const_iterator pneeded;
2882       for (pneeded = needed.begin(); pneeded != needed.end(); ++pneeded)
2883         {
2884           if (this->sonames_.find(*pneeded) == this->sonames_.end())
2885             {
2886               found_all = false;
2887               break;
2888             }
2889         }
2890       (*p)->set_has_unknown_needed_entries(!found_all);
2891
2892       // --copy-dt-needed-entries aka --add-needed is a GNU ld option
2893       // that gold does not support.  However, they cause no trouble
2894       // unless there is a DT_NEEDED entry that we don't know about;
2895       // warn only in that case.
2896       if (!found_all
2897           && !issued_copy_dt_needed_error
2898           && (parameters->options().copy_dt_needed_entries()
2899               || parameters->options().add_needed()))
2900         {
2901           const char* optname;
2902           if (parameters->options().copy_dt_needed_entries())
2903             optname = "--copy-dt-needed-entries";
2904           else
2905             optname = "--add-needed";
2906           gold_error(_("%s is not supported but is required for %s in %s"),
2907                      optname, (*pneeded).c_str(), (*p)->name().c_str());
2908           issued_copy_dt_needed_error = true;
2909         }
2910     }
2911 }
2912
2913 // Start processing an archive.
2914
2915 void
2916 Input_objects::archive_start(Archive* archive)
2917 {
2918   if (parameters->options().user_set_print_symbol_counts()
2919       || parameters->options().cref())
2920     {
2921       if (this->cref_ == NULL)
2922         this->cref_ = new Cref();
2923       this->cref_->add_archive_start(archive);
2924     }
2925 }
2926
2927 // Stop processing an archive.
2928
2929 void
2930 Input_objects::archive_stop(Archive* archive)
2931 {
2932   if (parameters->options().user_set_print_symbol_counts()
2933       || parameters->options().cref())
2934     this->cref_->add_archive_stop(archive);
2935 }
2936
2937 // Print symbol counts
2938
2939 void
2940 Input_objects::print_symbol_counts(const Symbol_table* symtab) const
2941 {
2942   if (parameters->options().user_set_print_symbol_counts()
2943       && this->cref_ != NULL)
2944     this->cref_->print_symbol_counts(symtab);
2945 }
2946
2947 // Print a cross reference table.
2948
2949 void
2950 Input_objects::print_cref(const Symbol_table* symtab, FILE* f) const
2951 {
2952   if (parameters->options().cref() && this->cref_ != NULL)
2953     this->cref_->print_cref(symtab, f);
2954 }
2955
2956 // Relocate_info methods.
2957
2958 // Return a string describing the location of a relocation when file
2959 // and lineno information is not available.  This is only used in
2960 // error messages.
2961
2962 template<int size, bool big_endian>
2963 std::string
2964 Relocate_info<size, big_endian>::location(size_t, off_t offset) const
2965 {
2966   Sized_dwarf_line_info<size, big_endian> line_info(this->object);
2967   std::string ret = line_info.addr2line(this->data_shndx, offset, NULL);
2968   if (!ret.empty())
2969     return ret;
2970
2971   ret = this->object->name();
2972
2973   Symbol_location_info info;
2974   if (this->object->get_symbol_location_info(this->data_shndx, offset, &info))
2975     {
2976       if (!info.source_file.empty())
2977         {
2978           ret += ":";
2979           ret += info.source_file;
2980         }
2981       size_t len = info.enclosing_symbol_name.length() + 100;
2982       char* buf = new char[len];
2983       snprintf(buf, len, _(":function %s"),
2984                info.enclosing_symbol_name.c_str());
2985       ret += buf;
2986       delete[] buf;
2987       return ret;
2988     }
2989
2990   ret += "(";
2991   ret += this->object->section_name(this->data_shndx);
2992   char buf[100];
2993   snprintf(buf, sizeof buf, "+0x%lx)", static_cast<long>(offset));
2994   ret += buf;
2995   return ret;
2996 }
2997
2998 } // End namespace gold.
2999
3000 namespace
3001 {
3002
3003 using namespace gold;
3004
3005 // Read an ELF file with the header and return the appropriate
3006 // instance of Object.
3007
3008 template<int size, bool big_endian>
3009 Object*
3010 make_elf_sized_object(const std::string& name, Input_file* input_file,
3011                       off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr,
3012                       bool* punconfigured)
3013 {
3014   Target* target = select_target(input_file, offset,
3015                                  ehdr.get_e_machine(), size, big_endian,
3016                                  ehdr.get_e_ident()[elfcpp::EI_OSABI],
3017                                  ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
3018   if (target == NULL)
3019     gold_fatal(_("%s: unsupported ELF machine number %d"),
3020                name.c_str(), ehdr.get_e_machine());
3021
3022   if (!parameters->target_valid())
3023     set_parameters_target(target);
3024   else if (target != &parameters->target())
3025     {
3026       if (punconfigured != NULL)
3027         *punconfigured = true;
3028       else
3029         gold_error(_("%s: incompatible target"), name.c_str());
3030       return NULL;
3031     }
3032
3033   return target->make_elf_object<size, big_endian>(name, input_file, offset,
3034                                                    ehdr);
3035 }
3036
3037 } // End anonymous namespace.
3038
3039 namespace gold
3040 {
3041
3042 // Return whether INPUT_FILE is an ELF object.
3043
3044 bool
3045 is_elf_object(Input_file* input_file, off_t offset,
3046               const unsigned char** start, int* read_size)
3047 {
3048   off_t filesize = input_file->file().filesize();
3049   int want = elfcpp::Elf_recognizer::max_header_size;
3050   if (filesize - offset < want)
3051     want = filesize - offset;
3052
3053   const unsigned char* p = input_file->file().get_view(offset, 0, want,
3054                                                        true, false);
3055   *start = p;
3056   *read_size = want;
3057
3058   return elfcpp::Elf_recognizer::is_elf_file(p, want);
3059 }
3060
3061 // Read an ELF file and return the appropriate instance of Object.
3062
3063 Object*
3064 make_elf_object(const std::string& name, Input_file* input_file, off_t offset,
3065                 const unsigned char* p, section_offset_type bytes,
3066                 bool* punconfigured)
3067 {
3068   if (punconfigured != NULL)
3069     *punconfigured = false;
3070
3071   std::string error;
3072   bool big_endian = false;
3073   int size = 0;
3074   if (!elfcpp::Elf_recognizer::is_valid_header(p, bytes, &size,
3075                                                &big_endian, &error))
3076     {
3077       gold_error(_("%s: %s"), name.c_str(), error.c_str());
3078       return NULL;
3079     }
3080
3081   if (size == 32)
3082     {
3083       if (big_endian)
3084         {
3085 #ifdef HAVE_TARGET_32_BIG
3086           elfcpp::Ehdr<32, true> ehdr(p);
3087           return make_elf_sized_object<32, true>(name, input_file,
3088                                                  offset, ehdr, punconfigured);
3089 #else
3090           if (punconfigured != NULL)
3091             *punconfigured = true;
3092           else
3093             gold_error(_("%s: not configured to support "
3094                          "32-bit big-endian object"),
3095                        name.c_str());
3096           return NULL;
3097 #endif
3098         }
3099       else
3100         {
3101 #ifdef HAVE_TARGET_32_LITTLE
3102           elfcpp::Ehdr<32, false> ehdr(p);
3103           return make_elf_sized_object<32, false>(name, input_file,
3104                                                   offset, ehdr, punconfigured);
3105 #else
3106           if (punconfigured != NULL)
3107             *punconfigured = true;
3108           else
3109             gold_error(_("%s: not configured to support "
3110                          "32-bit little-endian object"),
3111                        name.c_str());
3112           return NULL;
3113 #endif
3114         }
3115     }
3116   else if (size == 64)
3117     {
3118       if (big_endian)
3119         {
3120 #ifdef HAVE_TARGET_64_BIG
3121           elfcpp::Ehdr<64, true> ehdr(p);
3122           return make_elf_sized_object<64, true>(name, input_file,
3123                                                  offset, ehdr, punconfigured);
3124 #else
3125           if (punconfigured != NULL)
3126             *punconfigured = true;
3127           else
3128             gold_error(_("%s: not configured to support "
3129                          "64-bit big-endian object"),
3130                        name.c_str());
3131           return NULL;
3132 #endif
3133         }
3134       else
3135         {
3136 #ifdef HAVE_TARGET_64_LITTLE
3137           elfcpp::Ehdr<64, false> ehdr(p);
3138           return make_elf_sized_object<64, false>(name, input_file,
3139                                                   offset, ehdr, punconfigured);
3140 #else
3141           if (punconfigured != NULL)
3142             *punconfigured = true;
3143           else
3144             gold_error(_("%s: not configured to support "
3145                          "64-bit little-endian object"),
3146                        name.c_str());
3147           return NULL;
3148 #endif
3149         }
3150     }
3151   else
3152     gold_unreachable();
3153 }
3154
3155 // Instantiate the templates we need.
3156
3157 #ifdef HAVE_TARGET_32_LITTLE
3158 template
3159 void
3160 Object::read_section_data<32, false>(elfcpp::Elf_file<32, false, Object>*,
3161                                      Read_symbols_data*);
3162 #endif
3163
3164 #ifdef HAVE_TARGET_32_BIG
3165 template
3166 void
3167 Object::read_section_data<32, true>(elfcpp::Elf_file<32, true, Object>*,
3168                                     Read_symbols_data*);
3169 #endif
3170
3171 #ifdef HAVE_TARGET_64_LITTLE
3172 template
3173 void
3174 Object::read_section_data<64, false>(elfcpp::Elf_file<64, false, Object>*,
3175                                      Read_symbols_data*);
3176 #endif
3177
3178 #ifdef HAVE_TARGET_64_BIG
3179 template
3180 void
3181 Object::read_section_data<64, true>(elfcpp::Elf_file<64, true, Object>*,
3182                                     Read_symbols_data*);
3183 #endif
3184
3185 #ifdef HAVE_TARGET_32_LITTLE
3186 template
3187 class Sized_relobj_file<32, false>;
3188 #endif
3189
3190 #ifdef HAVE_TARGET_32_BIG
3191 template
3192 class Sized_relobj_file<32, true>;
3193 #endif
3194
3195 #ifdef HAVE_TARGET_64_LITTLE
3196 template
3197 class Sized_relobj_file<64, false>;
3198 #endif
3199
3200 #ifdef HAVE_TARGET_64_BIG
3201 template
3202 class Sized_relobj_file<64, true>;
3203 #endif
3204
3205 #ifdef HAVE_TARGET_32_LITTLE
3206 template
3207 struct Relocate_info<32, false>;
3208 #endif
3209
3210 #ifdef HAVE_TARGET_32_BIG
3211 template
3212 struct Relocate_info<32, true>;
3213 #endif
3214
3215 #ifdef HAVE_TARGET_64_LITTLE
3216 template
3217 struct Relocate_info<64, false>;
3218 #endif
3219
3220 #ifdef HAVE_TARGET_64_BIG
3221 template
3222 struct Relocate_info<64, true>;
3223 #endif
3224
3225 #ifdef HAVE_TARGET_32_LITTLE
3226 template
3227 void
3228 Xindex::initialize_symtab_xindex<32, false>(Object*, unsigned int);
3229
3230 template
3231 void
3232 Xindex::read_symtab_xindex<32, false>(Object*, unsigned int,
3233                                       const unsigned char*);
3234 #endif
3235
3236 #ifdef HAVE_TARGET_32_BIG
3237 template
3238 void
3239 Xindex::initialize_symtab_xindex<32, true>(Object*, unsigned int);
3240
3241 template
3242 void
3243 Xindex::read_symtab_xindex<32, true>(Object*, unsigned int,
3244                                      const unsigned char*);
3245 #endif
3246
3247 #ifdef HAVE_TARGET_64_LITTLE
3248 template
3249 void
3250 Xindex::initialize_symtab_xindex<64, false>(Object*, unsigned int);
3251
3252 template
3253 void
3254 Xindex::read_symtab_xindex<64, false>(Object*, unsigned int,
3255                                       const unsigned char*);
3256 #endif
3257
3258 #ifdef HAVE_TARGET_64_BIG
3259 template
3260 void
3261 Xindex::initialize_symtab_xindex<64, true>(Object*, unsigned int);
3262
3263 template
3264 void
3265 Xindex::read_symtab_xindex<64, true>(Object*, unsigned int,
3266                                      const unsigned char*);
3267 #endif
3268
3269 } // End namespace gold.