Merge branch 'vendor/GCC50'
[dragonfly.git] / contrib / binutils-2.24 / 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, 2013
4 // Free Software Foundation, Inc.
5 // Written by Ian Lance Taylor <iant@google.com>.
6
7 // This file is part of gold.
8
9 // This program is free software; you can redistribute it and/or modify
10 // it under the terms of the GNU General Public License as published by
11 // the Free Software Foundation; either version 3 of the License, or
12 // (at your option) any later version.
13
14 // This program is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 // GNU General Public License for more details.
18
19 // You should have received a copy of the GNU General Public License
20 // along with this program; if not, write to the Free Software
21 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22 // MA 02110-1301, USA.
23
24 #include "gold.h"
25
26 #include <cerrno>
27 #include <cstring>
28 #include <cstdarg>
29 #include "demangle.h"
30 #include "libiberty.h"
31
32 #include "gc.h"
33 #include "target-select.h"
34 #include "dwarf_reader.h"
35 #include "layout.h"
36 #include "output.h"
37 #include "symtab.h"
38 #include "cref.h"
39 #include "reloc.h"
40 #include "object.h"
41 #include "dynobj.h"
42 #include "plugin.h"
43 #include "compressed_output.h"
44 #include "incremental.h"
45
46 namespace gold
47 {
48
49 // Struct Read_symbols_data.
50
51 // Destroy any remaining File_view objects and buffers of decompressed
52 // sections.
53
54 Read_symbols_data::~Read_symbols_data()
55 {
56   if (this->section_headers != NULL)
57     delete this->section_headers;
58   if (this->section_names != NULL)
59     delete this->section_names;
60   if (this->symbols != NULL)
61     delete this->symbols;
62   if (this->symbol_names != NULL)
63     delete this->symbol_names;
64   if (this->versym != NULL)
65     delete this->versym;
66   if (this->verdef != NULL)
67     delete this->verdef;
68   if (this->verneed != NULL)
69     delete this->verneed;
70 }
71
72 // Class Xindex.
73
74 // Initialize the symtab_xindex_ array.  Find the SHT_SYMTAB_SHNDX
75 // section and read it in.  SYMTAB_SHNDX is the index of the symbol
76 // table we care about.
77
78 template<int size, bool big_endian>
79 void
80 Xindex::initialize_symtab_xindex(Object* object, unsigned int symtab_shndx)
81 {
82   if (!this->symtab_xindex_.empty())
83     return;
84
85   gold_assert(symtab_shndx != 0);
86
87   // Look through the sections in reverse order, on the theory that it
88   // is more likely to be near the end than the beginning.
89   unsigned int i = object->shnum();
90   while (i > 0)
91     {
92       --i;
93       if (object->section_type(i) == elfcpp::SHT_SYMTAB_SHNDX
94           && this->adjust_shndx(object->section_link(i)) == symtab_shndx)
95         {
96           this->read_symtab_xindex<size, big_endian>(object, i, NULL);
97           return;
98         }
99     }
100
101   object->error(_("missing SHT_SYMTAB_SHNDX section"));
102 }
103
104 // Read in the symtab_xindex_ array, given the section index of the
105 // SHT_SYMTAB_SHNDX section.  If PSHDRS is not NULL, it points at the
106 // section headers.
107
108 template<int size, bool big_endian>
109 void
110 Xindex::read_symtab_xindex(Object* object, unsigned int xindex_shndx,
111                            const unsigned char* pshdrs)
112 {
113   section_size_type bytecount;
114   const unsigned char* contents;
115   if (pshdrs == NULL)
116     contents = object->section_contents(xindex_shndx, &bytecount, false);
117   else
118     {
119       const unsigned char* p = (pshdrs
120                                 + (xindex_shndx
121                                    * elfcpp::Elf_sizes<size>::shdr_size));
122       typename elfcpp::Shdr<size, big_endian> shdr(p);
123       bytecount = convert_to_section_size_type(shdr.get_sh_size());
124       contents = object->get_view(shdr.get_sh_offset(), bytecount, true, false);
125     }
126
127   gold_assert(this->symtab_xindex_.empty());
128   this->symtab_xindex_.reserve(bytecount / 4);
129   for (section_size_type i = 0; i < bytecount; i += 4)
130     {
131       unsigned int shndx = elfcpp::Swap<32, big_endian>::readval(contents + i);
132       // We preadjust the section indexes we save.
133       this->symtab_xindex_.push_back(this->adjust_shndx(shndx));
134     }
135 }
136
137 // Symbol symndx has a section of SHN_XINDEX; return the real section
138 // index.
139
140 unsigned int
141 Xindex::sym_xindex_to_shndx(Object* object, unsigned int symndx)
142 {
143   if (symndx >= this->symtab_xindex_.size())
144     {
145       object->error(_("symbol %u out of range for SHT_SYMTAB_SHNDX section"),
146                     symndx);
147       return elfcpp::SHN_UNDEF;
148     }
149   unsigned int shndx = this->symtab_xindex_[symndx];
150   if (shndx < elfcpp::SHN_LORESERVE || shndx >= object->shnum())
151     {
152       object->error(_("extended index for symbol %u out of range: %u"),
153                     symndx, shndx);
154       return elfcpp::SHN_UNDEF;
155     }
156   return shndx;
157 }
158
159 // Class Object.
160
161 // Report an error for this object file.  This is used by the
162 // elfcpp::Elf_file interface, and also called by the Object code
163 // itself.
164
165 void
166 Object::error(const char* format, ...) const
167 {
168   va_list args;
169   va_start(args, format);
170   char* buf = NULL;
171   if (vasprintf(&buf, format, args) < 0)
172     gold_nomem();
173   va_end(args);
174   gold_error(_("%s: %s"), this->name().c_str(), buf);
175   free(buf);
176 }
177
178 // Return a view of the contents of a section.
179
180 const unsigned char*
181 Object::section_contents(unsigned int shndx, section_size_type* plen,
182                          bool cache)
183 { return this->do_section_contents(shndx, plen, cache); }
184
185 // Read the section data into SD.  This is code common to Sized_relobj_file
186 // and Sized_dynobj, so we put it into Object.
187
188 template<int size, bool big_endian>
189 void
190 Object::read_section_data(elfcpp::Elf_file<size, big_endian, Object>* elf_file,
191                           Read_symbols_data* sd)
192 {
193   const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
194
195   // Read the section headers.
196   const off_t shoff = elf_file->shoff();
197   const unsigned int shnum = this->shnum();
198   sd->section_headers = this->get_lasting_view(shoff, shnum * shdr_size,
199                                                true, true);
200
201   // Read the section names.
202   const unsigned char* pshdrs = sd->section_headers->data();
203   const unsigned char* pshdrnames = pshdrs + elf_file->shstrndx() * shdr_size;
204   typename elfcpp::Shdr<size, big_endian> shdrnames(pshdrnames);
205
206   if (shdrnames.get_sh_type() != elfcpp::SHT_STRTAB)
207     this->error(_("section name section has wrong type: %u"),
208                 static_cast<unsigned int>(shdrnames.get_sh_type()));
209
210   sd->section_names_size =
211     convert_to_section_size_type(shdrnames.get_sh_size());
212   sd->section_names = this->get_lasting_view(shdrnames.get_sh_offset(),
213                                              sd->section_names_size, false,
214                                              false);
215 }
216
217 // If NAME is the name of a special .gnu.warning section, arrange for
218 // the warning to be issued.  SHNDX is the section index.  Return
219 // whether it is a warning section.
220
221 bool
222 Object::handle_gnu_warning_section(const char* name, unsigned int shndx,
223                                    Symbol_table* symtab)
224 {
225   const char warn_prefix[] = ".gnu.warning.";
226   const int warn_prefix_len = sizeof warn_prefix - 1;
227   if (strncmp(name, warn_prefix, warn_prefix_len) == 0)
228     {
229       // Read the section contents to get the warning text.  It would
230       // be nicer if we only did this if we have to actually issue a
231       // warning.  Unfortunately, warnings are issued as we relocate
232       // sections.  That means that we can not lock the object then,
233       // as we might try to issue the same warning multiple times
234       // simultaneously.
235       section_size_type len;
236       const unsigned char* contents = this->section_contents(shndx, &len,
237                                                              false);
238       if (len == 0)
239         {
240           const char* warning = name + warn_prefix_len;
241           contents = reinterpret_cast<const unsigned char*>(warning);
242           len = strlen(warning);
243         }
244       std::string warning(reinterpret_cast<const char*>(contents), len);
245       symtab->add_warning(name + warn_prefix_len, this, warning);
246       return true;
247     }
248   return false;
249 }
250
251 // If NAME is the name of the special section which indicates that
252 // this object was compiled with -fsplit-stack, mark it accordingly.
253
254 bool
255 Object::handle_split_stack_section(const char* name)
256 {
257   if (strcmp(name, ".note.GNU-split-stack") == 0)
258     {
259       this->uses_split_stack_ = true;
260       return true;
261     }
262   if (strcmp(name, ".note.GNU-no-split-stack") == 0)
263     {
264       this->has_no_split_stack_ = true;
265       return true;
266     }
267   return false;
268 }
269
270 // Class Relobj
271
272 // To copy the symbols data read from the file to a local data structure.
273 // This function is called from do_layout only while doing garbage
274 // collection.
275
276 void
277 Relobj::copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd,
278                           unsigned int section_header_size)
279 {
280   gc_sd->section_headers_data =
281          new unsigned char[(section_header_size)];
282   memcpy(gc_sd->section_headers_data, sd->section_headers->data(),
283          section_header_size);
284   gc_sd->section_names_data =
285          new unsigned char[sd->section_names_size];
286   memcpy(gc_sd->section_names_data, sd->section_names->data(),
287          sd->section_names_size);
288   gc_sd->section_names_size = sd->section_names_size;
289   if (sd->symbols != NULL)
290     {
291       gc_sd->symbols_data =
292              new unsigned char[sd->symbols_size];
293       memcpy(gc_sd->symbols_data, sd->symbols->data(),
294             sd->symbols_size);
295     }
296   else
297     {
298       gc_sd->symbols_data = NULL;
299     }
300   gc_sd->symbols_size = sd->symbols_size;
301   gc_sd->external_symbols_offset = sd->external_symbols_offset;
302   if (sd->symbol_names != NULL)
303     {
304       gc_sd->symbol_names_data =
305              new unsigned char[sd->symbol_names_size];
306       memcpy(gc_sd->symbol_names_data, sd->symbol_names->data(),
307             sd->symbol_names_size);
308     }
309   else
310     {
311       gc_sd->symbol_names_data = NULL;
312     }
313   gc_sd->symbol_names_size = sd->symbol_names_size;
314 }
315
316 // This function determines if a particular section name must be included
317 // in the link.  This is used during garbage collection to determine the
318 // roots of the worklist.
319
320 bool
321 Relobj::is_section_name_included(const char* name)
322 {
323   if (is_prefix_of(".ctors", name)
324       || is_prefix_of(".dtors", name)
325       || is_prefix_of(".note", name)
326       || is_prefix_of(".init", name)
327       || is_prefix_of(".fini", name)
328       || is_prefix_of(".gcc_except_table", name)
329       || is_prefix_of(".jcr", name)
330       || is_prefix_of(".preinit_array", name)
331       || (is_prefix_of(".text", name)
332           && strstr(name, "personality"))
333       || (is_prefix_of(".data", name)
334           && strstr(name, "personality"))
335       || (is_prefix_of(".sdata", name)
336           && strstr(name, "personality"))
337       || (is_prefix_of(".gnu.linkonce.d", name)
338           && strstr(name, "personality")))
339     {
340       return true;
341     }
342   return false;
343 }
344
345 // Finalize the incremental relocation information.  Allocates a block
346 // of relocation entries for each symbol, and sets the reloc_bases_
347 // array to point to the first entry in each block.  If CLEAR_COUNTS
348 // is TRUE, also clear the per-symbol relocation counters.
349
350 void
351 Relobj::finalize_incremental_relocs(Layout* layout, bool clear_counts)
352 {
353   unsigned int nsyms = this->get_global_symbols()->size();
354   this->reloc_bases_ = new unsigned int[nsyms];
355
356   gold_assert(this->reloc_bases_ != NULL);
357   gold_assert(layout->incremental_inputs() != NULL);
358
359   unsigned int rindex = layout->incremental_inputs()->get_reloc_count();
360   for (unsigned int i = 0; i < nsyms; ++i)
361     {
362       this->reloc_bases_[i] = rindex;
363       rindex += this->reloc_counts_[i];
364       if (clear_counts)
365         this->reloc_counts_[i] = 0;
366     }
367   layout->incremental_inputs()->set_reloc_count(rindex);
368 }
369
370 // Class Sized_relobj.
371
372 // Iterate over local symbols, calling a visitor class V for each GOT offset
373 // associated with a local symbol.
374
375 template<int size, bool big_endian>
376 void
377 Sized_relobj<size, big_endian>::do_for_all_local_got_entries(
378     Got_offset_list::Visitor* v) const
379 {
380   unsigned int nsyms = this->local_symbol_count();
381   for (unsigned int i = 0; i < nsyms; i++)
382     {
383       Local_got_offsets::const_iterator p = this->local_got_offsets_.find(i);
384       if (p != this->local_got_offsets_.end())
385         {
386           const Got_offset_list* got_offsets = p->second;
387           got_offsets->for_all_got_offsets(v);
388         }
389     }
390 }
391
392 // Get the address of an output section.
393
394 template<int size, bool big_endian>
395 uint64_t
396 Sized_relobj<size, big_endian>::do_output_section_address(
397     unsigned int shndx)
398 {
399   // If the input file is linked as --just-symbols, the output
400   // section address is the input section address.
401   if (this->just_symbols())
402     return this->section_address(shndx);
403
404   const Output_section* os = this->do_output_section(shndx);
405   gold_assert(os != NULL);
406   return os->address();
407 }
408
409 // Class Sized_relobj_file.
410
411 template<int size, bool big_endian>
412 Sized_relobj_file<size, big_endian>::Sized_relobj_file(
413     const std::string& name,
414     Input_file* input_file,
415     off_t offset,
416     const elfcpp::Ehdr<size, big_endian>& ehdr)
417   : Sized_relobj<size, big_endian>(name, input_file, offset),
418     elf_file_(this, ehdr),
419     symtab_shndx_(-1U),
420     local_symbol_count_(0),
421     output_local_symbol_count_(0),
422     output_local_dynsym_count_(0),
423     symbols_(),
424     defined_count_(0),
425     local_symbol_offset_(0),
426     local_dynsym_offset_(0),
427     local_values_(),
428     local_plt_offsets_(),
429     kept_comdat_sections_(),
430     has_eh_frame_(false),
431     discarded_eh_frame_shndx_(-1U),
432     deferred_layout_(),
433     deferred_layout_relocs_(),
434     compressed_sections_()
435 {
436   this->e_type_ = ehdr.get_e_type();
437 }
438
439 template<int size, bool big_endian>
440 Sized_relobj_file<size, big_endian>::~Sized_relobj_file()
441 {
442 }
443
444 // Set up an object file based on the file header.  This sets up the
445 // section information.
446
447 template<int size, bool big_endian>
448 void
449 Sized_relobj_file<size, big_endian>::do_setup()
450 {
451   const unsigned int shnum = this->elf_file_.shnum();
452   this->set_shnum(shnum);
453 }
454
455 // Find the SHT_SYMTAB section, given the section headers.  The ELF
456 // standard says that maybe in the future there can be more than one
457 // SHT_SYMTAB section.  Until somebody figures out how that could
458 // work, we assume there is only one.
459
460 template<int size, bool big_endian>
461 void
462 Sized_relobj_file<size, big_endian>::find_symtab(const unsigned char* pshdrs)
463 {
464   const unsigned int shnum = this->shnum();
465   this->symtab_shndx_ = 0;
466   if (shnum > 0)
467     {
468       // Look through the sections in reverse order, since gas tends
469       // to put the symbol table at the end.
470       const unsigned char* p = pshdrs + shnum * This::shdr_size;
471       unsigned int i = shnum;
472       unsigned int xindex_shndx = 0;
473       unsigned int xindex_link = 0;
474       while (i > 0)
475         {
476           --i;
477           p -= This::shdr_size;
478           typename This::Shdr shdr(p);
479           if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB)
480             {
481               this->symtab_shndx_ = i;
482               if (xindex_shndx > 0 && xindex_link == i)
483                 {
484                   Xindex* xindex =
485                     new Xindex(this->elf_file_.large_shndx_offset());
486                   xindex->read_symtab_xindex<size, big_endian>(this,
487                                                                xindex_shndx,
488                                                                pshdrs);
489                   this->set_xindex(xindex);
490                 }
491               break;
492             }
493
494           // Try to pick up the SHT_SYMTAB_SHNDX section, if there is
495           // one.  This will work if it follows the SHT_SYMTAB
496           // section.
497           if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX)
498             {
499               xindex_shndx = i;
500               xindex_link = this->adjust_shndx(shdr.get_sh_link());
501             }
502         }
503     }
504 }
505
506 // Return the Xindex structure to use for object with lots of
507 // sections.
508
509 template<int size, bool big_endian>
510 Xindex*
511 Sized_relobj_file<size, big_endian>::do_initialize_xindex()
512 {
513   gold_assert(this->symtab_shndx_ != -1U);
514   Xindex* xindex = new Xindex(this->elf_file_.large_shndx_offset());
515   xindex->initialize_symtab_xindex<size, big_endian>(this, this->symtab_shndx_);
516   return xindex;
517 }
518
519 // Return whether SHDR has the right type and flags to be a GNU
520 // .eh_frame section.
521
522 template<int size, bool big_endian>
523 bool
524 Sized_relobj_file<size, big_endian>::check_eh_frame_flags(
525     const elfcpp::Shdr<size, big_endian>* shdr) const
526 {
527   elfcpp::Elf_Word sh_type = shdr->get_sh_type();
528   return ((sh_type == elfcpp::SHT_PROGBITS
529            || sh_type == elfcpp::SHT_X86_64_UNWIND)
530           && (shdr->get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
531 }
532
533 // Find the section header with the given name.
534
535 template<int size, bool big_endian>
536 const unsigned char*
537 Object::find_shdr(
538     const unsigned char* pshdrs,
539     const char* name,
540     const char* names,
541     section_size_type names_size,
542     const unsigned char* hdr) const
543 {
544   const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
545   const unsigned int shnum = this->shnum();
546   const unsigned char* hdr_end = pshdrs + shdr_size * shnum;
547   size_t sh_name = 0;
548
549   while (1)
550     {
551       if (hdr)
552         {
553           // We found HDR last time we were called, continue looking.
554           typename elfcpp::Shdr<size, big_endian> shdr(hdr);
555           sh_name = shdr.get_sh_name();
556         }
557       else
558         {
559           // Look for the next occurrence of NAME in NAMES.
560           // The fact that .shstrtab produced by current GNU tools is
561           // string merged means we shouldn't have both .not.foo and
562           // .foo in .shstrtab, and multiple .foo sections should all
563           // have the same sh_name.  However, this is not guaranteed
564           // by the ELF spec and not all ELF object file producers may
565           // be so clever.
566           size_t len = strlen(name) + 1;
567           const char *p = sh_name ? names + sh_name + len : names;
568           p = reinterpret_cast<const char*>(memmem(p, names_size - (p - names),
569                                                    name, len));
570           if (p == NULL)
571             return NULL;
572           sh_name = p - names;
573           hdr = pshdrs;
574           if (sh_name == 0)
575             return hdr;
576         }
577
578       hdr += shdr_size;
579       while (hdr < hdr_end)
580         {
581           typename elfcpp::Shdr<size, big_endian> shdr(hdr);
582           if (shdr.get_sh_name() == sh_name)
583             return hdr;
584           hdr += shdr_size;
585         }
586       hdr = NULL;
587       if (sh_name == 0)
588         return hdr;
589     }
590 }
591
592 // Return whether there is a GNU .eh_frame section, given the section
593 // headers and the section names.
594
595 template<int size, bool big_endian>
596 bool
597 Sized_relobj_file<size, big_endian>::find_eh_frame(
598     const unsigned char* pshdrs,
599     const char* names,
600     section_size_type names_size) const
601 {
602   const unsigned char* s = NULL;
603
604   while (1)
605     {
606       s = this->template find_shdr<size, big_endian>(pshdrs, ".eh_frame",
607                                                      names, names_size, s);
608       if (s == NULL)
609         return false;
610
611       typename This::Shdr shdr(s);
612       if (this->check_eh_frame_flags(&shdr))
613         return true;
614     }
615 }
616
617 // Return TRUE if this is a section whose contents will be needed in the
618 // Add_symbols task.  This function is only called for sections that have
619 // already passed the test in is_compressed_debug_section(), so we know
620 // that the section name begins with ".zdebug".
621
622 static bool
623 need_decompressed_section(const char* name)
624 {
625   // Skip over the ".zdebug" and a quick check for the "_".
626   name += 7;
627   if (*name++ != '_')
628     return false;
629
630 #ifdef ENABLE_THREADS
631   // Decompressing these sections now will help only if we're
632   // multithreaded.
633   if (parameters->options().threads())
634     {
635       // We will need .zdebug_str if this is not an incremental link
636       // (i.e., we are processing string merge sections) or if we need
637       // to build a gdb index.
638       if ((!parameters->incremental() || parameters->options().gdb_index())
639           && strcmp(name, "str") == 0)
640         return true;
641
642       // We will need these other sections when building a gdb index.
643       if (parameters->options().gdb_index()
644           && (strcmp(name, "info") == 0
645               || strcmp(name, "types") == 0
646               || strcmp(name, "pubnames") == 0
647               || strcmp(name, "pubtypes") == 0
648               || strcmp(name, "ranges") == 0
649               || strcmp(name, "abbrev") == 0))
650         return true;
651     }
652 #endif
653
654   // Even when single-threaded, we will need .zdebug_str if this is
655   // not an incremental link and we are building a gdb index.
656   // Otherwise, we would decompress the section twice: once for
657   // string merge processing, and once for building the gdb index.
658   if (!parameters->incremental()
659       && parameters->options().gdb_index()
660       && strcmp(name, "str") == 0)
661     return true;
662
663   return false;
664 }
665
666 // Build a table for any compressed debug sections, mapping each section index
667 // to the uncompressed size and (if needed) the decompressed contents.
668
669 template<int size, bool big_endian>
670 Compressed_section_map*
671 build_compressed_section_map(
672     const unsigned char* pshdrs,
673     unsigned int shnum,
674     const char* names,
675     section_size_type names_size,
676     Sized_relobj_file<size, big_endian>* obj)
677 {
678   Compressed_section_map* uncompressed_map = new Compressed_section_map();
679   const unsigned int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
680   const unsigned char* p = pshdrs + shdr_size;
681
682   for (unsigned int i = 1; i < shnum; ++i, p += shdr_size)
683     {
684       typename elfcpp::Shdr<size, big_endian> shdr(p);
685       if (shdr.get_sh_type() == elfcpp::SHT_PROGBITS
686           && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
687         {
688           if (shdr.get_sh_name() >= names_size)
689             {
690               obj->error(_("bad section name offset for section %u: %lu"),
691                          i, static_cast<unsigned long>(shdr.get_sh_name()));
692               continue;
693             }
694
695           const char* name = names + shdr.get_sh_name();
696           if (is_compressed_debug_section(name))
697             {
698               section_size_type len;
699               const unsigned char* contents =
700                   obj->section_contents(i, &len, false);
701               uint64_t uncompressed_size = get_uncompressed_size(contents, len);
702               Compressed_section_info info;
703               info.size = convert_to_section_size_type(uncompressed_size);
704               info.contents = NULL;
705               if (uncompressed_size != -1ULL)
706                 {
707                   unsigned char* uncompressed_data = NULL;
708                   if (need_decompressed_section(name))
709                     {
710                       uncompressed_data = new unsigned char[uncompressed_size];
711                       if (decompress_input_section(contents, len,
712                                                    uncompressed_data,
713                                                    uncompressed_size))
714                         info.contents = uncompressed_data;
715                       else
716                         delete[] uncompressed_data;
717                     }
718                   (*uncompressed_map)[i] = info;
719                 }
720             }
721         }
722     }
723   return uncompressed_map;
724 }
725
726 // Stash away info for a number of special sections.
727 // Return true if any of the sections found require local symbols to be read.
728
729 template<int size, bool big_endian>
730 bool
731 Sized_relobj_file<size, big_endian>::do_find_special_sections(
732     Read_symbols_data* sd)
733 {
734   const unsigned char* const pshdrs = sd->section_headers->data();
735   const unsigned char* namesu = sd->section_names->data();
736   const char* names = reinterpret_cast<const char*>(namesu);
737
738   if (this->find_eh_frame(pshdrs, names, sd->section_names_size))
739     this->has_eh_frame_ = true;
740
741   if (memmem(names, sd->section_names_size, ".zdebug_", 8) != NULL)
742     this->compressed_sections_
743       = build_compressed_section_map(pshdrs, this->shnum(), names,
744                                      sd->section_names_size, this);
745   return (this->has_eh_frame_
746           || (!parameters->options().relocatable()
747               && parameters->options().gdb_index()
748               && (memmem(names, sd->section_names_size, "debug_info", 12) == 0
749                   || memmem(names, sd->section_names_size, "debug_types",
750                             13) == 0)));
751 }
752
753 // Read the sections and symbols from an object file.
754
755 template<int size, bool big_endian>
756 void
757 Sized_relobj_file<size, big_endian>::do_read_symbols(Read_symbols_data* sd)
758 {
759   this->read_section_data(&this->elf_file_, sd);
760
761   const unsigned char* const pshdrs = sd->section_headers->data();
762
763   this->find_symtab(pshdrs);
764
765   bool need_local_symbols = this->do_find_special_sections(sd);
766
767   sd->symbols = NULL;
768   sd->symbols_size = 0;
769   sd->external_symbols_offset = 0;
770   sd->symbol_names = NULL;
771   sd->symbol_names_size = 0;
772
773   if (this->symtab_shndx_ == 0)
774     {
775       // No symbol table.  Weird but legal.
776       return;
777     }
778
779   // Get the symbol table section header.
780   typename This::Shdr symtabshdr(pshdrs
781                                  + this->symtab_shndx_ * This::shdr_size);
782   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
783
784   // If this object has a .eh_frame section, or if building a .gdb_index
785   // section and there is debug info, we need all the symbols.
786   // Otherwise we only need the external symbols.  While it would be
787   // simpler to just always read all the symbols, I've seen object
788   // files with well over 2000 local symbols, which for a 64-bit
789   // object file format is over 5 pages that we don't need to read
790   // now.
791
792   const int sym_size = This::sym_size;
793   const unsigned int loccount = symtabshdr.get_sh_info();
794   this->local_symbol_count_ = loccount;
795   this->local_values_.resize(loccount);
796   section_offset_type locsize = loccount * sym_size;
797   off_t dataoff = symtabshdr.get_sh_offset();
798   section_size_type datasize =
799     convert_to_section_size_type(symtabshdr.get_sh_size());
800   off_t extoff = dataoff + locsize;
801   section_size_type extsize = datasize - locsize;
802
803   off_t readoff = need_local_symbols ? dataoff : extoff;
804   section_size_type readsize = need_local_symbols ? datasize : extsize;
805
806   if (readsize == 0)
807     {
808       // No external symbols.  Also weird but also legal.
809       return;
810     }
811
812   File_view* fvsymtab = this->get_lasting_view(readoff, readsize, true, false);
813
814   // Read the section header for the symbol names.
815   unsigned int strtab_shndx = this->adjust_shndx(symtabshdr.get_sh_link());
816   if (strtab_shndx >= this->shnum())
817     {
818       this->error(_("invalid symbol table name index: %u"), strtab_shndx);
819       return;
820     }
821   typename This::Shdr strtabshdr(pshdrs + strtab_shndx * This::shdr_size);
822   if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB)
823     {
824       this->error(_("symbol table name section has wrong type: %u"),
825                   static_cast<unsigned int>(strtabshdr.get_sh_type()));
826       return;
827     }
828
829   // Read the symbol names.
830   File_view* fvstrtab = this->get_lasting_view(strtabshdr.get_sh_offset(),
831                                                strtabshdr.get_sh_size(),
832                                                false, true);
833
834   sd->symbols = fvsymtab;
835   sd->symbols_size = readsize;
836   sd->external_symbols_offset = need_local_symbols ? locsize : 0;
837   sd->symbol_names = fvstrtab;
838   sd->symbol_names_size =
839     convert_to_section_size_type(strtabshdr.get_sh_size());
840 }
841
842 // Return the section index of symbol SYM.  Set *VALUE to its value in
843 // the object file.  Set *IS_ORDINARY if this is an ordinary section
844 // index, not a special code between SHN_LORESERVE and SHN_HIRESERVE.
845 // Note that for a symbol which is not defined in this object file,
846 // this will set *VALUE to 0 and return SHN_UNDEF; it will not return
847 // the final value of the symbol in the link.
848
849 template<int size, bool big_endian>
850 unsigned int
851 Sized_relobj_file<size, big_endian>::symbol_section_and_value(unsigned int sym,
852                                                               Address* value,
853                                                               bool* is_ordinary)
854 {
855   section_size_type symbols_size;
856   const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
857                                                         &symbols_size,
858                                                         false);
859
860   const size_t count = symbols_size / This::sym_size;
861   gold_assert(sym < count);
862
863   elfcpp::Sym<size, big_endian> elfsym(symbols + sym * This::sym_size);
864   *value = elfsym.get_st_value();
865
866   return this->adjust_sym_shndx(sym, elfsym.get_st_shndx(), is_ordinary);
867 }
868
869 // Return whether to include a section group in the link.  LAYOUT is
870 // used to keep track of which section groups we have already seen.
871 // INDEX is the index of the section group and SHDR is the section
872 // header.  If we do not want to include this group, we set bits in
873 // OMIT for each section which should be discarded.
874
875 template<int size, bool big_endian>
876 bool
877 Sized_relobj_file<size, big_endian>::include_section_group(
878     Symbol_table* symtab,
879     Layout* layout,
880     unsigned int index,
881     const char* name,
882     const unsigned char* shdrs,
883     const char* section_names,
884     section_size_type section_names_size,
885     std::vector<bool>* omit)
886 {
887   // Read the section contents.
888   typename This::Shdr shdr(shdrs + index * This::shdr_size);
889   const unsigned char* pcon = this->get_view(shdr.get_sh_offset(),
890                                              shdr.get_sh_size(), true, false);
891   const elfcpp::Elf_Word* pword =
892     reinterpret_cast<const elfcpp::Elf_Word*>(pcon);
893
894   // The first word contains flags.  We only care about COMDAT section
895   // groups.  Other section groups are always included in the link
896   // just like ordinary sections.
897   elfcpp::Elf_Word flags = elfcpp::Swap<32, big_endian>::readval(pword);
898
899   // Look up the group signature, which is the name of a symbol.  ELF
900   // uses a symbol name because some group signatures are long, and
901   // the name is generally already in the symbol table, so it makes
902   // sense to put the long string just once in .strtab rather than in
903   // both .strtab and .shstrtab.
904
905   // Get the appropriate symbol table header (this will normally be
906   // the single SHT_SYMTAB section, but in principle it need not be).
907   const unsigned int link = this->adjust_shndx(shdr.get_sh_link());
908   typename This::Shdr symshdr(this, this->elf_file_.section_header(link));
909
910   // Read the symbol table entry.
911   unsigned int symndx = shdr.get_sh_info();
912   if (symndx >= symshdr.get_sh_size() / This::sym_size)
913     {
914       this->error(_("section group %u info %u out of range"),
915                   index, symndx);
916       return false;
917     }
918   off_t symoff = symshdr.get_sh_offset() + symndx * This::sym_size;
919   const unsigned char* psym = this->get_view(symoff, This::sym_size, true,
920                                              false);
921   elfcpp::Sym<size, big_endian> sym(psym);
922
923   // Read the symbol table names.
924   section_size_type symnamelen;
925   const unsigned char* psymnamesu;
926   psymnamesu = this->section_contents(this->adjust_shndx(symshdr.get_sh_link()),
927                                       &symnamelen, true);
928   const char* psymnames = reinterpret_cast<const char*>(psymnamesu);
929
930   // Get the section group signature.
931   if (sym.get_st_name() >= symnamelen)
932     {
933       this->error(_("symbol %u name offset %u out of range"),
934                   symndx, sym.get_st_name());
935       return false;
936     }
937
938   std::string signature(psymnames + sym.get_st_name());
939
940   // It seems that some versions of gas will create a section group
941   // associated with a section symbol, and then fail to give a name to
942   // the section symbol.  In such a case, use the name of the section.
943   if (signature[0] == '\0' && sym.get_st_type() == elfcpp::STT_SECTION)
944     {
945       bool is_ordinary;
946       unsigned int sym_shndx = this->adjust_sym_shndx(symndx,
947                                                       sym.get_st_shndx(),
948                                                       &is_ordinary);
949       if (!is_ordinary || sym_shndx >= this->shnum())
950         {
951           this->error(_("symbol %u invalid section index %u"),
952                       symndx, sym_shndx);
953           return false;
954         }
955       typename This::Shdr member_shdr(shdrs + sym_shndx * This::shdr_size);
956       if (member_shdr.get_sh_name() < section_names_size)
957         signature = section_names + member_shdr.get_sh_name();
958     }
959
960   // Record this section group in the layout, and see whether we've already
961   // seen one with the same signature.
962   bool include_group;
963   bool is_comdat;
964   Kept_section* kept_section = NULL;
965
966   if ((flags & elfcpp::GRP_COMDAT) == 0)
967     {
968       include_group = true;
969       is_comdat = false;
970     }
971   else
972     {
973       include_group = layout->find_or_add_kept_section(signature,
974                                                        this, index, true,
975                                                        true, &kept_section);
976       is_comdat = true;
977     }
978
979   if (is_comdat && include_group)
980     {
981       Incremental_inputs* incremental_inputs = layout->incremental_inputs();
982       if (incremental_inputs != NULL)
983         incremental_inputs->report_comdat_group(this, signature.c_str());
984     }
985
986   size_t count = shdr.get_sh_size() / sizeof(elfcpp::Elf_Word);
987
988   std::vector<unsigned int> shndxes;
989   bool relocate_group = include_group && parameters->options().relocatable();
990   if (relocate_group)
991     shndxes.reserve(count - 1);
992
993   for (size_t i = 1; i < count; ++i)
994     {
995       elfcpp::Elf_Word shndx =
996         this->adjust_shndx(elfcpp::Swap<32, big_endian>::readval(pword + i));
997
998       if (relocate_group)
999         shndxes.push_back(shndx);
1000
1001       if (shndx >= this->shnum())
1002         {
1003           this->error(_("section %u in section group %u out of range"),
1004                       shndx, index);
1005           continue;
1006         }
1007
1008       // Check for an earlier section number, since we're going to get
1009       // it wrong--we may have already decided to include the section.
1010       if (shndx < index)
1011         this->error(_("invalid section group %u refers to earlier section %u"),
1012                     index, shndx);
1013
1014       // Get the name of the member section.
1015       typename This::Shdr member_shdr(shdrs + shndx * This::shdr_size);
1016       if (member_shdr.get_sh_name() >= section_names_size)
1017         {
1018           // This is an error, but it will be diagnosed eventually
1019           // in do_layout, so we don't need to do anything here but
1020           // ignore it.
1021           continue;
1022         }
1023       std::string mname(section_names + member_shdr.get_sh_name());
1024
1025       if (include_group)
1026         {
1027           if (is_comdat)
1028             kept_section->add_comdat_section(mname, shndx,
1029                                              member_shdr.get_sh_size());
1030         }
1031       else
1032         {
1033           (*omit)[shndx] = true;
1034
1035           if (is_comdat)
1036             {
1037               Relobj* kept_object = kept_section->object();
1038               if (kept_section->is_comdat())
1039                 {
1040                   // Find the corresponding kept section, and store
1041                   // that info in the discarded section table.
1042                   unsigned int kept_shndx;
1043                   uint64_t kept_size;
1044                   if (kept_section->find_comdat_section(mname, &kept_shndx,
1045                                                         &kept_size))
1046                     {
1047                       // We don't keep a mapping for this section if
1048                       // it has a different size.  The mapping is only
1049                       // used for relocation processing, and we don't
1050                       // want to treat the sections as similar if the
1051                       // sizes are different.  Checking the section
1052                       // size is the approach used by the GNU linker.
1053                       if (kept_size == member_shdr.get_sh_size())
1054                         this->set_kept_comdat_section(shndx, kept_object,
1055                                                       kept_shndx);
1056                     }
1057                 }
1058               else
1059                 {
1060                   // The existing section is a linkonce section.  Add
1061                   // a mapping if there is exactly one section in the
1062                   // group (which is true when COUNT == 2) and if it
1063                   // is the same size.
1064                   if (count == 2
1065                       && (kept_section->linkonce_size()
1066                           == member_shdr.get_sh_size()))
1067                     this->set_kept_comdat_section(shndx, kept_object,
1068                                                   kept_section->shndx());
1069                 }
1070             }
1071         }
1072     }
1073
1074   if (relocate_group)
1075     layout->layout_group(symtab, this, index, name, signature.c_str(),
1076                          shdr, flags, &shndxes);
1077
1078   return include_group;
1079 }
1080
1081 // Whether to include a linkonce section in the link.  NAME is the
1082 // name of the section and SHDR is the section header.
1083
1084 // Linkonce sections are a GNU extension implemented in the original
1085 // GNU linker before section groups were defined.  The semantics are
1086 // that we only include one linkonce section with a given name.  The
1087 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
1088 // where T is the type of section and SYMNAME is the name of a symbol.
1089 // In an attempt to make linkonce sections interact well with section
1090 // groups, we try to identify SYMNAME and use it like a section group
1091 // signature.  We want to block section groups with that signature,
1092 // but not other linkonce sections with that signature.  We also use
1093 // the full name of the linkonce section as a normal section group
1094 // signature.
1095
1096 template<int size, bool big_endian>
1097 bool
1098 Sized_relobj_file<size, big_endian>::include_linkonce_section(
1099     Layout* layout,
1100     unsigned int index,
1101     const char* name,
1102     const elfcpp::Shdr<size, big_endian>& shdr)
1103 {
1104   typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
1105   // In general the symbol name we want will be the string following
1106   // the last '.'.  However, we have to handle the case of
1107   // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
1108   // some versions of gcc.  So we use a heuristic: if the name starts
1109   // with ".gnu.linkonce.t.", we use everything after that.  Otherwise
1110   // we look for the last '.'.  We can't always simply skip
1111   // ".gnu.linkonce.X", because we have to deal with cases like
1112   // ".gnu.linkonce.d.rel.ro.local".
1113   const char* const linkonce_t = ".gnu.linkonce.t.";
1114   const char* symname;
1115   if (strncmp(name, linkonce_t, strlen(linkonce_t)) == 0)
1116     symname = name + strlen(linkonce_t);
1117   else
1118     symname = strrchr(name, '.') + 1;
1119   std::string sig1(symname);
1120   std::string sig2(name);
1121   Kept_section* kept1;
1122   Kept_section* kept2;
1123   bool include1 = layout->find_or_add_kept_section(sig1, this, index, false,
1124                                                    false, &kept1);
1125   bool include2 = layout->find_or_add_kept_section(sig2, this, index, false,
1126                                                    true, &kept2);
1127
1128   if (!include2)
1129     {
1130       // We are not including this section because we already saw the
1131       // name of the section as a signature.  This normally implies
1132       // that the kept section is another linkonce section.  If it is
1133       // the same size, record it as the section which corresponds to
1134       // this one.
1135       if (kept2->object() != NULL
1136           && !kept2->is_comdat()
1137           && kept2->linkonce_size() == sh_size)
1138         this->set_kept_comdat_section(index, kept2->object(), kept2->shndx());
1139     }
1140   else if (!include1)
1141     {
1142       // The section is being discarded on the basis of its symbol
1143       // name.  This means that the corresponding kept section was
1144       // part of a comdat group, and it will be difficult to identify
1145       // the specific section within that group that corresponds to
1146       // this linkonce section.  We'll handle the simple case where
1147       // the group has only one member section.  Otherwise, it's not
1148       // worth the effort.
1149       unsigned int kept_shndx;
1150       uint64_t kept_size;
1151       if (kept1->object() != NULL
1152           && kept1->is_comdat()
1153           && kept1->find_single_comdat_section(&kept_shndx, &kept_size)
1154           && kept_size == sh_size)
1155         this->set_kept_comdat_section(index, kept1->object(), kept_shndx);
1156     }
1157   else
1158     {
1159       kept1->set_linkonce_size(sh_size);
1160       kept2->set_linkonce_size(sh_size);
1161     }
1162
1163   return include1 && include2;
1164 }
1165
1166 // Layout an input section.
1167
1168 template<int size, bool big_endian>
1169 inline void
1170 Sized_relobj_file<size, big_endian>::layout_section(
1171     Layout* layout,
1172     unsigned int shndx,
1173     const char* name,
1174     const typename This::Shdr& shdr,
1175     unsigned int reloc_shndx,
1176     unsigned int reloc_type)
1177 {
1178   off_t offset;
1179   Output_section* os = layout->layout(this, shndx, name, shdr,
1180                                           reloc_shndx, reloc_type, &offset);
1181
1182   this->output_sections()[shndx] = os;
1183   if (offset == -1)
1184     this->section_offsets()[shndx] = invalid_address;
1185   else
1186     this->section_offsets()[shndx] = convert_types<Address, off_t>(offset);
1187
1188   // If this section requires special handling, and if there are
1189   // relocs that apply to it, then we must do the special handling
1190   // before we apply the relocs.
1191   if (offset == -1 && reloc_shndx != 0)
1192     this->set_relocs_must_follow_section_writes();
1193 }
1194
1195 // Layout an input .eh_frame section.
1196
1197 template<int size, bool big_endian>
1198 void
1199 Sized_relobj_file<size, big_endian>::layout_eh_frame_section(
1200     Layout* layout,
1201     const unsigned char* symbols_data,
1202     section_size_type symbols_size,
1203     const unsigned char* symbol_names_data,
1204     section_size_type symbol_names_size,
1205     unsigned int shndx,
1206     const typename This::Shdr& shdr,
1207     unsigned int reloc_shndx,
1208     unsigned int reloc_type)
1209 {
1210   gold_assert(this->has_eh_frame_);
1211
1212   off_t offset;
1213   Output_section* os = layout->layout_eh_frame(this,
1214                                                symbols_data,
1215                                                symbols_size,
1216                                                symbol_names_data,
1217                                                symbol_names_size,
1218                                                shndx,
1219                                                shdr,
1220                                                reloc_shndx,
1221                                                reloc_type,
1222                                                &offset);
1223   this->output_sections()[shndx] = os;
1224   if (os == NULL || offset == -1)
1225     {
1226       // An object can contain at most one section holding exception
1227       // frame information.
1228       gold_assert(this->discarded_eh_frame_shndx_ == -1U);
1229       this->discarded_eh_frame_shndx_ = shndx;
1230       this->section_offsets()[shndx] = invalid_address;
1231     }
1232   else
1233     this->section_offsets()[shndx] = convert_types<Address, off_t>(offset);
1234
1235   // If this section requires special handling, and if there are
1236   // relocs that aply to it, then we must do the special handling
1237   // before we apply the relocs.
1238   if (os != NULL && offset == -1 && reloc_shndx != 0)
1239     this->set_relocs_must_follow_section_writes();
1240 }
1241
1242 // Lay out the input sections.  We walk through the sections and check
1243 // whether they should be included in the link.  If they should, we
1244 // pass them to the Layout object, which will return an output section
1245 // and an offset.
1246 // This function is called twice sometimes, two passes, when mapping
1247 // of input sections to output sections must be delayed.
1248 // This is true for the following :
1249 // * Garbage collection (--gc-sections): Some input sections will be
1250 // discarded and hence the assignment must wait until the second pass.
1251 // In the first pass,  it is for setting up some sections as roots to
1252 // a work-list for --gc-sections and to do comdat processing.
1253 // * Identical Code Folding (--icf=<safe,all>): Some input sections
1254 // will be folded and hence the assignment must wait.
1255 // * Using plugins to map some sections to unique segments: Mapping
1256 // some sections to unique segments requires mapping them to unique
1257 // output sections too.  This can be done via plugins now and this
1258 // information is not available in the first pass.
1259
1260 template<int size, bool big_endian>
1261 void
1262 Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
1263                                                Layout* layout,
1264                                                Read_symbols_data* sd)
1265 {
1266   const unsigned int shnum = this->shnum();
1267
1268   /* Should this function be called twice?  */
1269   bool is_two_pass = (parameters->options().gc_sections()
1270                       || parameters->options().icf_enabled()
1271                       || layout->is_unique_segment_for_sections_specified());
1272
1273   /* Only one of is_pass_one and is_pass_two is true.  Both are false when
1274      a two-pass approach is not needed.  */
1275   bool is_pass_one = false;
1276   bool is_pass_two = false;
1277
1278   Symbols_data* gc_sd = NULL;
1279
1280   /* Check if do_layout needs to be two-pass.  If so, find out which pass
1281      should happen.  In the first pass, the data in sd is saved to be used
1282      later in the second pass.  */
1283   if (is_two_pass)
1284     {
1285       gc_sd = this->get_symbols_data();
1286       if (gc_sd == NULL)
1287         {
1288           gold_assert(sd != NULL);
1289           is_pass_one = true;
1290         }
1291       else
1292         {
1293           if (parameters->options().gc_sections())
1294             gold_assert(symtab->gc()->is_worklist_ready());
1295           if (parameters->options().icf_enabled())
1296             gold_assert(symtab->icf()->is_icf_ready()); 
1297           is_pass_two = true;
1298         }
1299     }
1300     
1301   if (shnum == 0)
1302     return;
1303
1304   if (is_pass_one)
1305     {
1306       // During garbage collection save the symbols data to use it when
1307       // re-entering this function.
1308       gc_sd = new Symbols_data;
1309       this->copy_symbols_data(gc_sd, sd, This::shdr_size * shnum);
1310       this->set_symbols_data(gc_sd);
1311     }
1312
1313   const unsigned char* section_headers_data = NULL;
1314   section_size_type section_names_size;
1315   const unsigned char* symbols_data = NULL;
1316   section_size_type symbols_size;
1317   const unsigned char* symbol_names_data = NULL;
1318   section_size_type symbol_names_size;
1319
1320   if (is_two_pass)
1321     {
1322       section_headers_data = gc_sd->section_headers_data;
1323       section_names_size = gc_sd->section_names_size;
1324       symbols_data = gc_sd->symbols_data;
1325       symbols_size = gc_sd->symbols_size;
1326       symbol_names_data = gc_sd->symbol_names_data;
1327       symbol_names_size = gc_sd->symbol_names_size;
1328     }
1329   else
1330     {
1331       section_headers_data = sd->section_headers->data();
1332       section_names_size = sd->section_names_size;
1333       if (sd->symbols != NULL)
1334         symbols_data = sd->symbols->data();
1335       symbols_size = sd->symbols_size;
1336       if (sd->symbol_names != NULL)
1337         symbol_names_data = sd->symbol_names->data();
1338       symbol_names_size = sd->symbol_names_size;
1339     }
1340
1341   // Get the section headers.
1342   const unsigned char* shdrs = section_headers_data;
1343   const unsigned char* pshdrs;
1344
1345   // Get the section names.
1346   const unsigned char* pnamesu = (is_two_pass
1347                                   ? gc_sd->section_names_data
1348                                   : sd->section_names->data());
1349
1350   const char* pnames = reinterpret_cast<const char*>(pnamesu);
1351
1352   // If any input files have been claimed by plugins, we need to defer
1353   // actual layout until the replacement files have arrived.
1354   const bool should_defer_layout =
1355       (parameters->options().has_plugins()
1356        && parameters->options().plugins()->should_defer_layout());
1357   unsigned int num_sections_to_defer = 0;
1358
1359   // For each section, record the index of the reloc section if any.
1360   // Use 0 to mean that there is no reloc section, -1U to mean that
1361   // there is more than one.
1362   std::vector<unsigned int> reloc_shndx(shnum, 0);
1363   std::vector<unsigned int> reloc_type(shnum, elfcpp::SHT_NULL);
1364   // Skip the first, dummy, section.
1365   pshdrs = shdrs + This::shdr_size;
1366   for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1367     {
1368       typename This::Shdr shdr(pshdrs);
1369
1370       // Count the number of sections whose layout will be deferred.
1371       if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1372         ++num_sections_to_defer;
1373
1374       unsigned int sh_type = shdr.get_sh_type();
1375       if (sh_type == elfcpp::SHT_REL || sh_type == elfcpp::SHT_RELA)
1376         {
1377           unsigned int target_shndx = this->adjust_shndx(shdr.get_sh_info());
1378           if (target_shndx == 0 || target_shndx >= shnum)
1379             {
1380               this->error(_("relocation section %u has bad info %u"),
1381                           i, target_shndx);
1382               continue;
1383             }
1384
1385           if (reloc_shndx[target_shndx] != 0)
1386             reloc_shndx[target_shndx] = -1U;
1387           else
1388             {
1389               reloc_shndx[target_shndx] = i;
1390               reloc_type[target_shndx] = sh_type;
1391             }
1392         }
1393     }
1394
1395   Output_sections& out_sections(this->output_sections());
1396   std::vector<Address>& out_section_offsets(this->section_offsets());
1397
1398   if (!is_pass_two)
1399     {
1400       out_sections.resize(shnum);
1401       out_section_offsets.resize(shnum);
1402     }
1403
1404   // If we are only linking for symbols, then there is nothing else to
1405   // do here.
1406   if (this->input_file()->just_symbols())
1407     {
1408       if (!is_pass_two)
1409         {
1410           delete sd->section_headers;
1411           sd->section_headers = NULL;
1412           delete sd->section_names;
1413           sd->section_names = NULL;
1414         }
1415       return;
1416     }
1417
1418   if (num_sections_to_defer > 0)
1419     {
1420       parameters->options().plugins()->add_deferred_layout_object(this);
1421       this->deferred_layout_.reserve(num_sections_to_defer);
1422     }
1423
1424   // Whether we've seen a .note.GNU-stack section.
1425   bool seen_gnu_stack = false;
1426   // The flags of a .note.GNU-stack section.
1427   uint64_t gnu_stack_flags = 0;
1428
1429   // Keep track of which sections to omit.
1430   std::vector<bool> omit(shnum, false);
1431
1432   // Keep track of reloc sections when emitting relocations.
1433   const bool relocatable = parameters->options().relocatable();
1434   const bool emit_relocs = (relocatable
1435                             || parameters->options().emit_relocs());
1436   std::vector<unsigned int> reloc_sections;
1437
1438   // Keep track of .eh_frame sections.
1439   std::vector<unsigned int> eh_frame_sections;
1440
1441   // Keep track of .debug_info and .debug_types sections.
1442   std::vector<unsigned int> debug_info_sections;
1443   std::vector<unsigned int> debug_types_sections;
1444
1445   // Skip the first, dummy, section.
1446   pshdrs = shdrs + This::shdr_size;
1447   for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1448     {
1449       typename This::Shdr shdr(pshdrs);
1450
1451       if (shdr.get_sh_name() >= section_names_size)
1452         {
1453           this->error(_("bad section name offset for section %u: %lu"),
1454                       i, static_cast<unsigned long>(shdr.get_sh_name()));
1455           return;
1456         }
1457
1458       const char* name = pnames + shdr.get_sh_name();
1459
1460       if (!is_pass_two)
1461         {
1462           if (this->handle_gnu_warning_section(name, i, symtab))
1463             {
1464               if (!relocatable && !parameters->options().shared())
1465                 omit[i] = true;
1466             }
1467
1468           // The .note.GNU-stack section is special.  It gives the
1469           // protection flags that this object file requires for the stack
1470           // in memory.
1471           if (strcmp(name, ".note.GNU-stack") == 0)
1472             {
1473               seen_gnu_stack = true;
1474               gnu_stack_flags |= shdr.get_sh_flags();
1475               omit[i] = true;
1476             }
1477
1478           // The .note.GNU-split-stack section is also special.  It
1479           // indicates that the object was compiled with
1480           // -fsplit-stack.
1481           if (this->handle_split_stack_section(name))
1482             {
1483               if (!relocatable && !parameters->options().shared())
1484                 omit[i] = true;
1485             }
1486
1487           // Skip attributes section.
1488           if (parameters->target().is_attributes_section(name))
1489             {
1490               omit[i] = true;
1491             }
1492
1493           bool discard = omit[i];
1494           if (!discard)
1495             {
1496               if (shdr.get_sh_type() == elfcpp::SHT_GROUP)
1497                 {
1498                   if (!this->include_section_group(symtab, layout, i, name,
1499                                                    shdrs, pnames,
1500                                                    section_names_size,
1501                                                    &omit))
1502                     discard = true;
1503                 }
1504               else if ((shdr.get_sh_flags() & elfcpp::SHF_GROUP) == 0
1505                        && Layout::is_linkonce(name))
1506                 {
1507                   if (!this->include_linkonce_section(layout, i, name, shdr))
1508                     discard = true;
1509                 }
1510             }
1511
1512           // Add the section to the incremental inputs layout.
1513           Incremental_inputs* incremental_inputs = layout->incremental_inputs();
1514           if (incremental_inputs != NULL
1515               && !discard
1516               && can_incremental_update(shdr.get_sh_type()))
1517             {
1518               off_t sh_size = shdr.get_sh_size();
1519               section_size_type uncompressed_size;
1520               if (this->section_is_compressed(i, &uncompressed_size))
1521                 sh_size = uncompressed_size;
1522               incremental_inputs->report_input_section(this, i, name, sh_size);
1523             }
1524
1525           if (discard)
1526             {
1527               // Do not include this section in the link.
1528               out_sections[i] = NULL;
1529               out_section_offsets[i] = invalid_address;
1530               continue;
1531             }
1532         }
1533
1534       if (is_pass_one && parameters->options().gc_sections())
1535         {
1536           if (this->is_section_name_included(name)
1537               || layout->keep_input_section (this, name)
1538               || shdr.get_sh_type() == elfcpp::SHT_INIT_ARRAY
1539               || shdr.get_sh_type() == elfcpp::SHT_FINI_ARRAY)
1540             {
1541               symtab->gc()->worklist().push(Section_id(this, i));
1542             }
1543           // If the section name XXX can be represented as a C identifier
1544           // it cannot be discarded if there are references to
1545           // __start_XXX and __stop_XXX symbols.  These need to be
1546           // specially handled.
1547           if (is_cident(name))
1548             {
1549               symtab->gc()->add_cident_section(name, Section_id(this, i));
1550             }
1551         }
1552
1553       // When doing a relocatable link we are going to copy input
1554       // reloc sections into the output.  We only want to copy the
1555       // ones associated with sections which are not being discarded.
1556       // However, we don't know that yet for all sections.  So save
1557       // reloc sections and process them later. Garbage collection is
1558       // not triggered when relocatable code is desired.
1559       if (emit_relocs
1560           && (shdr.get_sh_type() == elfcpp::SHT_REL
1561               || shdr.get_sh_type() == elfcpp::SHT_RELA))
1562         {
1563           reloc_sections.push_back(i);
1564           continue;
1565         }
1566
1567       if (relocatable && shdr.get_sh_type() == elfcpp::SHT_GROUP)
1568         continue;
1569
1570       // The .eh_frame section is special.  It holds exception frame
1571       // information that we need to read in order to generate the
1572       // exception frame header.  We process these after all the other
1573       // sections so that the exception frame reader can reliably
1574       // determine which sections are being discarded, and discard the
1575       // corresponding information.
1576       if (!relocatable
1577           && strcmp(name, ".eh_frame") == 0
1578           && this->check_eh_frame_flags(&shdr))
1579         {
1580           if (is_pass_one)
1581             {
1582               out_sections[i] = reinterpret_cast<Output_section*>(1);
1583               out_section_offsets[i] = invalid_address;
1584             }
1585           else if (should_defer_layout)
1586             this->deferred_layout_.push_back(Deferred_layout(i, name,
1587                                                              pshdrs,
1588                                                              reloc_shndx[i],
1589                                                              reloc_type[i]));
1590           else
1591             eh_frame_sections.push_back(i);
1592           continue;
1593         }
1594
1595       if (is_pass_two && parameters->options().gc_sections())
1596         {
1597           // This is executed during the second pass of garbage
1598           // collection. do_layout has been called before and some
1599           // sections have been already discarded. Simply ignore
1600           // such sections this time around.
1601           if (out_sections[i] == NULL)
1602             {
1603               gold_assert(out_section_offsets[i] == invalid_address);
1604               continue;
1605             }
1606           if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1607               && symtab->gc()->is_section_garbage(this, i))
1608               {
1609                 if (parameters->options().print_gc_sections())
1610                   gold_info(_("%s: removing unused section from '%s'"
1611                               " in file '%s'"),
1612                             program_name, this->section_name(i).c_str(),
1613                             this->name().c_str());
1614                 out_sections[i] = NULL;
1615                 out_section_offsets[i] = invalid_address;
1616                 continue;
1617               }
1618         }
1619
1620       if (is_pass_two && parameters->options().icf_enabled())
1621         {
1622           if (out_sections[i] == NULL)
1623             {
1624               gold_assert(out_section_offsets[i] == invalid_address);
1625               continue;
1626             }
1627           if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1628               && symtab->icf()->is_section_folded(this, i))
1629               {
1630                 if (parameters->options().print_icf_sections())
1631                   {
1632                     Section_id folded =
1633                                 symtab->icf()->get_folded_section(this, i);
1634                     Relobj* folded_obj =
1635                                 reinterpret_cast<Relobj*>(folded.first);
1636                     gold_info(_("%s: ICF folding section '%s' in file '%s'"
1637                                 "into '%s' in file '%s'"),
1638                               program_name, this->section_name(i).c_str(),
1639                               this->name().c_str(),
1640                               folded_obj->section_name(folded.second).c_str(),
1641                               folded_obj->name().c_str());
1642                   }
1643                 out_sections[i] = NULL;
1644                 out_section_offsets[i] = invalid_address;
1645                 continue;
1646               }
1647         }
1648
1649       // Defer layout here if input files are claimed by plugins.  When gc
1650       // is turned on this function is called twice.  For the second call
1651       // should_defer_layout should be false.
1652       if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1653         {
1654           gold_assert(!is_pass_two);
1655           this->deferred_layout_.push_back(Deferred_layout(i, name,
1656                                                            pshdrs,
1657                                                            reloc_shndx[i],
1658                                                            reloc_type[i]));
1659           // Put dummy values here; real values will be supplied by
1660           // do_layout_deferred_sections.
1661           out_sections[i] = reinterpret_cast<Output_section*>(2);
1662           out_section_offsets[i] = invalid_address;
1663           continue;
1664         }
1665
1666       // During gc_pass_two if a section that was previously deferred is
1667       // found, do not layout the section as layout_deferred_sections will
1668       // do it later from gold.cc.
1669       if (is_pass_two
1670           && (out_sections[i] == reinterpret_cast<Output_section*>(2)))
1671         continue;
1672
1673       if (is_pass_one)
1674         {
1675           // This is during garbage collection. The out_sections are
1676           // assigned in the second call to this function.
1677           out_sections[i] = reinterpret_cast<Output_section*>(1);
1678           out_section_offsets[i] = invalid_address;
1679         }
1680       else
1681         {
1682           // When garbage collection is switched on the actual layout
1683           // only happens in the second call.
1684           this->layout_section(layout, i, name, shdr, reloc_shndx[i],
1685                                reloc_type[i]);
1686
1687           // When generating a .gdb_index section, we do additional
1688           // processing of .debug_info and .debug_types sections after all
1689           // the other sections for the same reason as above.
1690           if (!relocatable
1691               && parameters->options().gdb_index()
1692               && !(shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1693             {
1694               if (strcmp(name, ".debug_info") == 0
1695                   || strcmp(name, ".zdebug_info") == 0)
1696                 debug_info_sections.push_back(i);
1697               else if (strcmp(name, ".debug_types") == 0
1698                        || strcmp(name, ".zdebug_types") == 0)
1699                 debug_types_sections.push_back(i);
1700             }
1701         }
1702     }
1703
1704   if (!is_pass_two)
1705     layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags, this);
1706
1707   // When doing a relocatable link handle the reloc sections at the
1708   // end.  Garbage collection  and Identical Code Folding is not
1709   // turned on for relocatable code.
1710   if (emit_relocs)
1711     this->size_relocatable_relocs();
1712
1713   gold_assert(!is_two_pass || reloc_sections.empty());
1714
1715   for (std::vector<unsigned int>::const_iterator p = reloc_sections.begin();
1716        p != reloc_sections.end();
1717        ++p)
1718     {
1719       unsigned int i = *p;
1720       const unsigned char* pshdr;
1721       pshdr = section_headers_data + i * This::shdr_size;
1722       typename This::Shdr shdr(pshdr);
1723
1724       unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1725       if (data_shndx >= shnum)
1726         {
1727           // We already warned about this above.
1728           continue;
1729         }
1730
1731       Output_section* data_section = out_sections[data_shndx];
1732       if (data_section == reinterpret_cast<Output_section*>(2))
1733         {
1734           // The layout for the data section was deferred, so we need
1735           // to defer the relocation section, too.
1736           const char* name = pnames + shdr.get_sh_name();
1737           this->deferred_layout_relocs_.push_back(
1738               Deferred_layout(i, name, pshdr, 0, elfcpp::SHT_NULL));
1739           out_sections[i] = reinterpret_cast<Output_section*>(2);
1740           out_section_offsets[i] = invalid_address;
1741           continue;
1742         }
1743       if (data_section == NULL)
1744         {
1745           out_sections[i] = NULL;
1746           out_section_offsets[i] = invalid_address;
1747           continue;
1748         }
1749
1750       Relocatable_relocs* rr = new Relocatable_relocs();
1751       this->set_relocatable_relocs(i, rr);
1752
1753       Output_section* os = layout->layout_reloc(this, i, shdr, data_section,
1754                                                 rr);
1755       out_sections[i] = os;
1756       out_section_offsets[i] = invalid_address;
1757     }
1758
1759   // Handle the .eh_frame sections at the end.
1760   gold_assert(!is_pass_one || eh_frame_sections.empty());
1761   for (std::vector<unsigned int>::const_iterator p = eh_frame_sections.begin();
1762        p != eh_frame_sections.end();
1763        ++p)
1764     {
1765       unsigned int i = *p;
1766       const unsigned char* pshdr;
1767       pshdr = section_headers_data + i * This::shdr_size;
1768       typename This::Shdr shdr(pshdr);
1769
1770       this->layout_eh_frame_section(layout,
1771                                     symbols_data,
1772                                     symbols_size,
1773                                     symbol_names_data,
1774                                     symbol_names_size,
1775                                     i,
1776                                     shdr,
1777                                     reloc_shndx[i],
1778                                     reloc_type[i]);
1779     }
1780
1781   // When building a .gdb_index section, scan the .debug_info and
1782   // .debug_types sections.
1783   gold_assert(!is_pass_one
1784               || (debug_info_sections.empty() && debug_types_sections.empty()));
1785   for (std::vector<unsigned int>::const_iterator p
1786            = debug_info_sections.begin();
1787        p != debug_info_sections.end();
1788        ++p)
1789     {
1790       unsigned int i = *p;
1791       layout->add_to_gdb_index(false, this, symbols_data, symbols_size,
1792                                i, reloc_shndx[i], reloc_type[i]);
1793     }
1794   for (std::vector<unsigned int>::const_iterator p
1795            = debug_types_sections.begin();
1796        p != debug_types_sections.end();
1797        ++p)
1798     {
1799       unsigned int i = *p;
1800       layout->add_to_gdb_index(true, this, symbols_data, symbols_size,
1801                                i, reloc_shndx[i], reloc_type[i]);
1802     }
1803
1804   if (is_pass_two)
1805     {
1806       delete[] gc_sd->section_headers_data;
1807       delete[] gc_sd->section_names_data;
1808       delete[] gc_sd->symbols_data;
1809       delete[] gc_sd->symbol_names_data;
1810       this->set_symbols_data(NULL);
1811     }
1812   else
1813     {
1814       delete sd->section_headers;
1815       sd->section_headers = NULL;
1816       delete sd->section_names;
1817       sd->section_names = NULL;
1818     }
1819 }
1820
1821 // Layout sections whose layout was deferred while waiting for
1822 // input files from a plugin.
1823
1824 template<int size, bool big_endian>
1825 void
1826 Sized_relobj_file<size, big_endian>::do_layout_deferred_sections(Layout* layout)
1827 {
1828   typename std::vector<Deferred_layout>::iterator deferred;
1829
1830   for (deferred = this->deferred_layout_.begin();
1831        deferred != this->deferred_layout_.end();
1832        ++deferred)
1833     {
1834       typename This::Shdr shdr(deferred->shdr_data_);
1835
1836       if (!parameters->options().relocatable()
1837           && deferred->name_ == ".eh_frame"
1838           && this->check_eh_frame_flags(&shdr))
1839         {
1840           // Checking is_section_included is not reliable for
1841           // .eh_frame sections, because they do not have an output
1842           // section.  This is not a problem normally because we call
1843           // layout_eh_frame_section unconditionally, but when
1844           // deferring sections that is not true.  We don't want to
1845           // keep all .eh_frame sections because that will cause us to
1846           // keep all sections that they refer to, which is the wrong
1847           // way around.  Instead, the eh_frame code will discard
1848           // .eh_frame sections that refer to discarded sections.
1849
1850           // Reading the symbols again here may be slow.
1851           Read_symbols_data sd;
1852           this->read_symbols(&sd);
1853           this->layout_eh_frame_section(layout,
1854                                         sd.symbols->data(),
1855                                         sd.symbols_size,
1856                                         sd.symbol_names->data(),
1857                                         sd.symbol_names_size,
1858                                         deferred->shndx_,
1859                                         shdr,
1860                                         deferred->reloc_shndx_,
1861                                         deferred->reloc_type_);
1862           continue;
1863         }
1864
1865       // If the section is not included, it is because the garbage collector
1866       // decided it is not needed.  Avoid reverting that decision.
1867       if (!this->is_section_included(deferred->shndx_))
1868         continue;
1869
1870       this->layout_section(layout, deferred->shndx_, deferred->name_.c_str(),
1871                            shdr, deferred->reloc_shndx_,
1872                            deferred->reloc_type_);
1873     }
1874
1875   this->deferred_layout_.clear();
1876
1877   // Now handle the deferred relocation sections.
1878
1879   Output_sections& out_sections(this->output_sections());
1880   std::vector<Address>& out_section_offsets(this->section_offsets());
1881
1882   for (deferred = this->deferred_layout_relocs_.begin();
1883        deferred != this->deferred_layout_relocs_.end();
1884        ++deferred)
1885     {
1886       unsigned int shndx = deferred->shndx_;
1887       typename This::Shdr shdr(deferred->shdr_data_);
1888       unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1889
1890       Output_section* data_section = out_sections[data_shndx];
1891       if (data_section == NULL)
1892         {
1893           out_sections[shndx] = NULL;
1894           out_section_offsets[shndx] = invalid_address;
1895           continue;
1896         }
1897
1898       Relocatable_relocs* rr = new Relocatable_relocs();
1899       this->set_relocatable_relocs(shndx, rr);
1900
1901       Output_section* os = layout->layout_reloc(this, shndx, shdr,
1902                                                 data_section, rr);
1903       out_sections[shndx] = os;
1904       out_section_offsets[shndx] = invalid_address;
1905     }
1906 }
1907
1908 // Add the symbols to the symbol table.
1909
1910 template<int size, bool big_endian>
1911 void
1912 Sized_relobj_file<size, big_endian>::do_add_symbols(Symbol_table* symtab,
1913                                                     Read_symbols_data* sd,
1914                                                     Layout*)
1915 {
1916   if (sd->symbols == NULL)
1917     {
1918       gold_assert(sd->symbol_names == NULL);
1919       return;
1920     }
1921
1922   const int sym_size = This::sym_size;
1923   size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1924                      / sym_size);
1925   if (symcount * sym_size != sd->symbols_size - sd->external_symbols_offset)
1926     {
1927       this->error(_("size of symbols is not multiple of symbol size"));
1928       return;
1929     }
1930
1931   this->symbols_.resize(symcount);
1932
1933   const char* sym_names =
1934     reinterpret_cast<const char*>(sd->symbol_names->data());
1935   symtab->add_from_relobj(this,
1936                           sd->symbols->data() + sd->external_symbols_offset,
1937                           symcount, this->local_symbol_count_,
1938                           sym_names, sd->symbol_names_size,
1939                           &this->symbols_,
1940                           &this->defined_count_);
1941
1942   delete sd->symbols;
1943   sd->symbols = NULL;
1944   delete sd->symbol_names;
1945   sd->symbol_names = NULL;
1946 }
1947
1948 // Find out if this object, that is a member of a lib group, should be included
1949 // in the link. We check every symbol defined by this object. If the symbol
1950 // table has a strong undefined reference to that symbol, we have to include
1951 // the object.
1952
1953 template<int size, bool big_endian>
1954 Archive::Should_include
1955 Sized_relobj_file<size, big_endian>::do_should_include_member(
1956     Symbol_table* symtab,
1957     Layout* layout,
1958     Read_symbols_data* sd,
1959     std::string* why)
1960 {
1961   char* tmpbuf = NULL;
1962   size_t tmpbuflen = 0;
1963   const char* sym_names =
1964       reinterpret_cast<const char*>(sd->symbol_names->data());
1965   const unsigned char* syms =
1966       sd->symbols->data() + sd->external_symbols_offset;
1967   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1968   size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1969                          / sym_size);
1970
1971   const unsigned char* p = syms;
1972
1973   for (size_t i = 0; i < symcount; ++i, p += sym_size)
1974     {
1975       elfcpp::Sym<size, big_endian> sym(p);
1976       unsigned int st_shndx = sym.get_st_shndx();
1977       if (st_shndx == elfcpp::SHN_UNDEF)
1978         continue;
1979
1980       unsigned int st_name = sym.get_st_name();
1981       const char* name = sym_names + st_name;
1982       Symbol* symbol;
1983       Archive::Should_include t = Archive::should_include_member(symtab,
1984                                                                  layout,
1985                                                                  name,
1986                                                                  &symbol, why,
1987                                                                  &tmpbuf,
1988                                                                  &tmpbuflen);
1989       if (t == Archive::SHOULD_INCLUDE_YES)
1990         {
1991           if (tmpbuf != NULL)
1992             free(tmpbuf);
1993           return t;
1994         }
1995     }
1996   if (tmpbuf != NULL)
1997     free(tmpbuf);
1998   return Archive::SHOULD_INCLUDE_UNKNOWN;
1999 }
2000
2001 // Iterate over global defined symbols, calling a visitor class V for each.
2002
2003 template<int size, bool big_endian>
2004 void
2005 Sized_relobj_file<size, big_endian>::do_for_all_global_symbols(
2006     Read_symbols_data* sd,
2007     Library_base::Symbol_visitor_base* v)
2008 {
2009   const char* sym_names =
2010       reinterpret_cast<const char*>(sd->symbol_names->data());
2011   const unsigned char* syms =
2012       sd->symbols->data() + sd->external_symbols_offset;
2013   const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2014   size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
2015                      / sym_size);
2016   const unsigned char* p = syms;
2017
2018   for (size_t i = 0; i < symcount; ++i, p += sym_size)
2019     {
2020       elfcpp::Sym<size, big_endian> sym(p);
2021       if (sym.get_st_shndx() != elfcpp::SHN_UNDEF)
2022         v->visit(sym_names + sym.get_st_name());
2023     }
2024 }
2025
2026 // Return whether the local symbol SYMNDX has a PLT offset.
2027
2028 template<int size, bool big_endian>
2029 bool
2030 Sized_relobj_file<size, big_endian>::local_has_plt_offset(
2031     unsigned int symndx) const
2032 {
2033   typename Local_plt_offsets::const_iterator p =
2034     this->local_plt_offsets_.find(symndx);
2035   return p != this->local_plt_offsets_.end();
2036 }
2037
2038 // Get the PLT offset of a local symbol.
2039
2040 template<int size, bool big_endian>
2041 unsigned int
2042 Sized_relobj_file<size, big_endian>::do_local_plt_offset(
2043     unsigned int symndx) const
2044 {
2045   typename Local_plt_offsets::const_iterator p =
2046     this->local_plt_offsets_.find(symndx);
2047   gold_assert(p != this->local_plt_offsets_.end());
2048   return p->second;
2049 }
2050
2051 // Set the PLT offset of a local symbol.
2052
2053 template<int size, bool big_endian>
2054 void
2055 Sized_relobj_file<size, big_endian>::set_local_plt_offset(
2056     unsigned int symndx, unsigned int plt_offset)
2057 {
2058   std::pair<typename Local_plt_offsets::iterator, bool> ins =
2059     this->local_plt_offsets_.insert(std::make_pair(symndx, plt_offset));
2060   gold_assert(ins.second);
2061 }
2062
2063 // First pass over the local symbols.  Here we add their names to
2064 // *POOL and *DYNPOOL, and we store the symbol value in
2065 // THIS->LOCAL_VALUES_.  This function is always called from a
2066 // singleton thread.  This is followed by a call to
2067 // finalize_local_symbols.
2068
2069 template<int size, bool big_endian>
2070 void
2071 Sized_relobj_file<size, big_endian>::do_count_local_symbols(Stringpool* pool,
2072                                                             Stringpool* dynpool)
2073 {
2074   gold_assert(this->symtab_shndx_ != -1U);
2075   if (this->symtab_shndx_ == 0)
2076     {
2077       // This object has no symbols.  Weird but legal.
2078       return;
2079     }
2080
2081   // Read the symbol table section header.
2082   const unsigned int symtab_shndx = this->symtab_shndx_;
2083   typename This::Shdr symtabshdr(this,
2084                                  this->elf_file_.section_header(symtab_shndx));
2085   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
2086
2087   // Read the local symbols.
2088   const int sym_size = This::sym_size;
2089   const unsigned int loccount = this->local_symbol_count_;
2090   gold_assert(loccount == symtabshdr.get_sh_info());
2091   off_t locsize = loccount * sym_size;
2092   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
2093                                               locsize, true, true);
2094
2095   // Read the symbol names.
2096   const unsigned int strtab_shndx =
2097     this->adjust_shndx(symtabshdr.get_sh_link());
2098   section_size_type strtab_size;
2099   const unsigned char* pnamesu = this->section_contents(strtab_shndx,
2100                                                         &strtab_size,
2101                                                         true);
2102   const char* pnames = reinterpret_cast<const char*>(pnamesu);
2103
2104   // Loop over the local symbols.
2105
2106   const Output_sections& out_sections(this->output_sections());
2107   unsigned int shnum = this->shnum();
2108   unsigned int count = 0;
2109   unsigned int dyncount = 0;
2110   // Skip the first, dummy, symbol.
2111   psyms += sym_size;
2112   bool strip_all = parameters->options().strip_all();
2113   bool discard_all = parameters->options().discard_all();
2114   bool discard_locals = parameters->options().discard_locals();
2115   for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
2116     {
2117       elfcpp::Sym<size, big_endian> sym(psyms);
2118
2119       Symbol_value<size>& lv(this->local_values_[i]);
2120
2121       bool is_ordinary;
2122       unsigned int shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
2123                                                   &is_ordinary);
2124       lv.set_input_shndx(shndx, is_ordinary);
2125
2126       if (sym.get_st_type() == elfcpp::STT_SECTION)
2127         lv.set_is_section_symbol();
2128       else if (sym.get_st_type() == elfcpp::STT_TLS)
2129         lv.set_is_tls_symbol();
2130       else if (sym.get_st_type() == elfcpp::STT_GNU_IFUNC)
2131         lv.set_is_ifunc_symbol();
2132
2133       // Save the input symbol value for use in do_finalize_local_symbols().
2134       lv.set_input_value(sym.get_st_value());
2135
2136       // Decide whether this symbol should go into the output file.
2137
2138       if ((shndx < shnum && out_sections[shndx] == NULL)
2139           || shndx == this->discarded_eh_frame_shndx_)
2140         {
2141           lv.set_no_output_symtab_entry();
2142           gold_assert(!lv.needs_output_dynsym_entry());
2143           continue;
2144         }
2145
2146       if (sym.get_st_type() == elfcpp::STT_SECTION
2147           || !this->adjust_local_symbol(&lv))
2148         {
2149           lv.set_no_output_symtab_entry();
2150           gold_assert(!lv.needs_output_dynsym_entry());
2151           continue;
2152         }
2153
2154       if (sym.get_st_name() >= strtab_size)
2155         {
2156           this->error(_("local symbol %u section name out of range: %u >= %u"),
2157                       i, sym.get_st_name(),
2158                       static_cast<unsigned int>(strtab_size));
2159           lv.set_no_output_symtab_entry();
2160           continue;
2161         }
2162
2163       const char* name = pnames + sym.get_st_name();
2164
2165       // If needed, add the symbol to the dynamic symbol table string pool.
2166       if (lv.needs_output_dynsym_entry())
2167         {
2168           dynpool->add(name, true, NULL);
2169           ++dyncount;
2170         }
2171
2172       if (strip_all
2173           || (discard_all && lv.may_be_discarded_from_output_symtab()))
2174         {
2175           lv.set_no_output_symtab_entry();
2176           continue;
2177         }
2178
2179       // If --discard-locals option is used, discard all temporary local
2180       // symbols.  These symbols start with system-specific local label
2181       // prefixes, typically .L for ELF system.  We want to be compatible
2182       // with GNU ld so here we essentially use the same check in
2183       // bfd_is_local_label().  The code is different because we already
2184       // know that:
2185       //
2186       //   - the symbol is local and thus cannot have global or weak binding.
2187       //   - the symbol is not a section symbol.
2188       //   - the symbol has a name.
2189       //
2190       // We do not discard a symbol if it needs a dynamic symbol entry.
2191       if (discard_locals
2192           && sym.get_st_type() != elfcpp::STT_FILE
2193           && !lv.needs_output_dynsym_entry()
2194           && lv.may_be_discarded_from_output_symtab()
2195           && parameters->target().is_local_label_name(name))
2196         {
2197           lv.set_no_output_symtab_entry();
2198           continue;
2199         }
2200
2201       // Discard the local symbol if -retain_symbols_file is specified
2202       // and the local symbol is not in that file.
2203       if (!parameters->options().should_retain_symbol(name))
2204         {
2205           lv.set_no_output_symtab_entry();
2206           continue;
2207         }
2208
2209       // Add the symbol to the symbol table string pool.
2210       pool->add(name, true, NULL);
2211       ++count;
2212     }
2213
2214   this->output_local_symbol_count_ = count;
2215   this->output_local_dynsym_count_ = dyncount;
2216 }
2217
2218 // Compute the final value of a local symbol.
2219
2220 template<int size, bool big_endian>
2221 typename Sized_relobj_file<size, big_endian>::Compute_final_local_value_status
2222 Sized_relobj_file<size, big_endian>::compute_final_local_value_internal(
2223     unsigned int r_sym,
2224     const Symbol_value<size>* lv_in,
2225     Symbol_value<size>* lv_out,
2226     bool relocatable,
2227     const Output_sections& out_sections,
2228     const std::vector<Address>& out_offsets,
2229     const Symbol_table* symtab)
2230 {
2231   // We are going to overwrite *LV_OUT, if it has a merged symbol value,
2232   // we may have a memory leak.
2233   gold_assert(lv_out->has_output_value());
2234
2235   bool is_ordinary;
2236   unsigned int shndx = lv_in->input_shndx(&is_ordinary);
2237
2238   // Set the output symbol value.
2239
2240   if (!is_ordinary)
2241     {
2242       if (shndx == elfcpp::SHN_ABS || Symbol::is_common_shndx(shndx))
2243         lv_out->set_output_value(lv_in->input_value());
2244       else
2245         {
2246           this->error(_("unknown section index %u for local symbol %u"),
2247                       shndx, r_sym);
2248           lv_out->set_output_value(0);
2249           return This::CFLV_ERROR;
2250         }
2251     }
2252   else
2253     {
2254       if (shndx >= this->shnum())
2255         {
2256           this->error(_("local symbol %u section index %u out of range"),
2257                       r_sym, shndx);
2258           lv_out->set_output_value(0);
2259           return This::CFLV_ERROR;
2260         }
2261
2262       Output_section* os = out_sections[shndx];
2263       Address secoffset = out_offsets[shndx];
2264       if (symtab->is_section_folded(this, shndx))
2265         {
2266           gold_assert(os == NULL && secoffset == invalid_address);
2267           // Get the os of the section it is folded onto.
2268           Section_id folded = symtab->icf()->get_folded_section(this,
2269                                                                 shndx);
2270           gold_assert(folded.first != NULL);
2271           Sized_relobj_file<size, big_endian>* folded_obj = reinterpret_cast
2272             <Sized_relobj_file<size, big_endian>*>(folded.first);
2273           os = folded_obj->output_section(folded.second);
2274           gold_assert(os != NULL);
2275           secoffset = folded_obj->get_output_section_offset(folded.second);
2276
2277           // This could be a relaxed input section.
2278           if (secoffset == invalid_address)
2279             {
2280               const Output_relaxed_input_section* relaxed_section =
2281                 os->find_relaxed_input_section(folded_obj, folded.second);
2282               gold_assert(relaxed_section != NULL);
2283               secoffset = relaxed_section->address() - os->address();
2284             }
2285         }
2286
2287       if (os == NULL)
2288         {
2289           // This local symbol belongs to a section we are discarding.
2290           // In some cases when applying relocations later, we will
2291           // attempt to match it to the corresponding kept section,
2292           // so we leave the input value unchanged here.
2293           return This::CFLV_DISCARDED;
2294         }
2295       else if (secoffset == invalid_address)
2296         {
2297           uint64_t start;
2298
2299           // This is a SHF_MERGE section or one which otherwise
2300           // requires special handling.
2301           if (shndx == this->discarded_eh_frame_shndx_)
2302             {
2303               // This local symbol belongs to a discarded .eh_frame
2304               // section.  Just treat it like the case in which
2305               // os == NULL above.
2306               gold_assert(this->has_eh_frame_);
2307               return This::CFLV_DISCARDED;
2308             }
2309           else if (!lv_in->is_section_symbol())
2310             {
2311               // This is not a section symbol.  We can determine
2312               // the final value now.
2313               lv_out->set_output_value(
2314                   os->output_address(this, shndx, lv_in->input_value()));
2315             }
2316           else if (!os->find_starting_output_address(this, shndx, &start))
2317             {
2318               // This is a section symbol, but apparently not one in a
2319               // merged section.  First check to see if this is a relaxed
2320               // input section.  If so, use its address.  Otherwise just
2321               // use the start of the output section.  This happens with
2322               // relocatable links when the input object has section
2323               // symbols for arbitrary non-merge sections.
2324               const Output_section_data* posd =
2325                 os->find_relaxed_input_section(this, shndx);
2326               if (posd != NULL)
2327                 {
2328                   Address relocatable_link_adjustment =
2329                     relocatable ? os->address() : 0;
2330                   lv_out->set_output_value(posd->address()
2331                                            - relocatable_link_adjustment);
2332                 }
2333               else
2334                 lv_out->set_output_value(os->address());
2335             }
2336           else
2337             {
2338               // We have to consider the addend to determine the
2339               // value to use in a relocation.  START is the start
2340               // of this input section.  If we are doing a relocatable
2341               // link, use offset from start output section instead of
2342               // address.
2343               Address adjusted_start =
2344                 relocatable ? start - os->address() : start;
2345               Merged_symbol_value<size>* msv =
2346                 new Merged_symbol_value<size>(lv_in->input_value(),
2347                                               adjusted_start);
2348               lv_out->set_merged_symbol_value(msv);
2349             }
2350         }
2351       else if (lv_in->is_tls_symbol())
2352         lv_out->set_output_value(os->tls_offset()
2353                                  + secoffset
2354                                  + lv_in->input_value());
2355       else
2356         lv_out->set_output_value((relocatable ? 0 : os->address())
2357                                  + secoffset
2358                                  + lv_in->input_value());
2359     }
2360   return This::CFLV_OK;
2361 }
2362
2363 // Compute final local symbol value.  R_SYM is the index of a local
2364 // symbol in symbol table.  LV points to a symbol value, which is
2365 // expected to hold the input value and to be over-written by the
2366 // final value.  SYMTAB points to a symbol table.  Some targets may want
2367 // to know would-be-finalized local symbol values in relaxation.
2368 // Hence we provide this method.  Since this method updates *LV, a
2369 // callee should make a copy of the original local symbol value and
2370 // use the copy instead of modifying an object's local symbols before
2371 // everything is finalized.  The caller should also free up any allocated
2372 // memory in the return value in *LV.
2373 template<int size, bool big_endian>
2374 typename Sized_relobj_file<size, big_endian>::Compute_final_local_value_status
2375 Sized_relobj_file<size, big_endian>::compute_final_local_value(
2376     unsigned int r_sym,
2377     const Symbol_value<size>* lv_in,
2378     Symbol_value<size>* lv_out,
2379     const Symbol_table* symtab)
2380 {
2381   // This is just a wrapper of compute_final_local_value_internal.
2382   const bool relocatable = parameters->options().relocatable();
2383   const Output_sections& out_sections(this->output_sections());
2384   const std::vector<Address>& out_offsets(this->section_offsets());
2385   return this->compute_final_local_value_internal(r_sym, lv_in, lv_out,
2386                                                   relocatable, out_sections,
2387                                                   out_offsets, symtab);
2388 }
2389
2390 // Finalize the local symbols.  Here we set the final value in
2391 // THIS->LOCAL_VALUES_ and set their output symbol table indexes.
2392 // This function is always called from a singleton thread.  The actual
2393 // output of the local symbols will occur in a separate task.
2394
2395 template<int size, bool big_endian>
2396 unsigned int
2397 Sized_relobj_file<size, big_endian>::do_finalize_local_symbols(
2398     unsigned int index,
2399     off_t off,
2400     Symbol_table* symtab)
2401 {
2402   gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
2403
2404   const unsigned int loccount = this->local_symbol_count_;
2405   this->local_symbol_offset_ = off;
2406
2407   const bool relocatable = parameters->options().relocatable();
2408   const Output_sections& out_sections(this->output_sections());
2409   const std::vector<Address>& out_offsets(this->section_offsets());
2410
2411   for (unsigned int i = 1; i < loccount; ++i)
2412     {
2413       Symbol_value<size>* lv = &this->local_values_[i];
2414
2415       Compute_final_local_value_status cflv_status =
2416         this->compute_final_local_value_internal(i, lv, lv, relocatable,
2417                                                  out_sections, out_offsets,
2418                                                  symtab);
2419       switch (cflv_status)
2420         {
2421         case CFLV_OK:
2422           if (!lv->is_output_symtab_index_set())
2423             {
2424               lv->set_output_symtab_index(index);
2425               ++index;
2426             }
2427           break;
2428         case CFLV_DISCARDED:
2429         case CFLV_ERROR:
2430           // Do nothing.
2431           break;
2432         default:
2433           gold_unreachable();
2434         }
2435     }
2436   return index;
2437 }
2438
2439 // Set the output dynamic symbol table indexes for the local variables.
2440
2441 template<int size, bool big_endian>
2442 unsigned int
2443 Sized_relobj_file<size, big_endian>::do_set_local_dynsym_indexes(
2444     unsigned int index)
2445 {
2446   const unsigned int loccount = this->local_symbol_count_;
2447   for (unsigned int i = 1; i < loccount; ++i)
2448     {
2449       Symbol_value<size>& lv(this->local_values_[i]);
2450       if (lv.needs_output_dynsym_entry())
2451         {
2452           lv.set_output_dynsym_index(index);
2453           ++index;
2454         }
2455     }
2456   return index;
2457 }
2458
2459 // Set the offset where local dynamic symbol information will be stored.
2460 // Returns the count of local symbols contributed to the symbol table by
2461 // this object.
2462
2463 template<int size, bool big_endian>
2464 unsigned int
2465 Sized_relobj_file<size, big_endian>::do_set_local_dynsym_offset(off_t off)
2466 {
2467   gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
2468   this->local_dynsym_offset_ = off;
2469   return this->output_local_dynsym_count_;
2470 }
2471
2472 // If Symbols_data is not NULL get the section flags from here otherwise
2473 // get it from the file.
2474
2475 template<int size, bool big_endian>
2476 uint64_t
2477 Sized_relobj_file<size, big_endian>::do_section_flags(unsigned int shndx)
2478 {
2479   Symbols_data* sd = this->get_symbols_data();
2480   if (sd != NULL)
2481     {
2482       const unsigned char* pshdrs = sd->section_headers_data
2483                                     + This::shdr_size * shndx;
2484       typename This::Shdr shdr(pshdrs);
2485       return shdr.get_sh_flags();
2486     }
2487   // If sd is NULL, read the section header from the file.
2488   return this->elf_file_.section_flags(shndx);
2489 }
2490
2491 // Get the section's ent size from Symbols_data.  Called by get_section_contents
2492 // in icf.cc
2493
2494 template<int size, bool big_endian>
2495 uint64_t
2496 Sized_relobj_file<size, big_endian>::do_section_entsize(unsigned int shndx)
2497 {
2498   Symbols_data* sd = this->get_symbols_data();
2499   gold_assert(sd != NULL);
2500
2501   const unsigned char* pshdrs = sd->section_headers_data
2502                                 + This::shdr_size * shndx;
2503   typename This::Shdr shdr(pshdrs);
2504   return shdr.get_sh_entsize();
2505 }
2506
2507 // Write out the local symbols.
2508
2509 template<int size, bool big_endian>
2510 void
2511 Sized_relobj_file<size, big_endian>::write_local_symbols(
2512     Output_file* of,
2513     const Stringpool* sympool,
2514     const Stringpool* dynpool,
2515     Output_symtab_xindex* symtab_xindex,
2516     Output_symtab_xindex* dynsym_xindex,
2517     off_t symtab_off)
2518 {
2519   const bool strip_all = parameters->options().strip_all();
2520   if (strip_all)
2521     {
2522       if (this->output_local_dynsym_count_ == 0)
2523         return;
2524       this->output_local_symbol_count_ = 0;
2525     }
2526
2527   gold_assert(this->symtab_shndx_ != -1U);
2528   if (this->symtab_shndx_ == 0)
2529     {
2530       // This object has no symbols.  Weird but legal.
2531       return;
2532     }
2533
2534   // Read the symbol table section header.
2535   const unsigned int symtab_shndx = this->symtab_shndx_;
2536   typename This::Shdr symtabshdr(this,
2537                                  this->elf_file_.section_header(symtab_shndx));
2538   gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
2539   const unsigned int loccount = this->local_symbol_count_;
2540   gold_assert(loccount == symtabshdr.get_sh_info());
2541
2542   // Read the local symbols.
2543   const int sym_size = This::sym_size;
2544   off_t locsize = loccount * sym_size;
2545   const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
2546                                               locsize, true, false);
2547
2548   // Read the symbol names.
2549   const unsigned int strtab_shndx =
2550     this->adjust_shndx(symtabshdr.get_sh_link());
2551   section_size_type strtab_size;
2552   const unsigned char* pnamesu = this->section_contents(strtab_shndx,
2553                                                         &strtab_size,
2554                                                         false);
2555   const char* pnames = reinterpret_cast<const char*>(pnamesu);
2556
2557   // Get views into the output file for the portions of the symbol table
2558   // and the dynamic symbol table that we will be writing.
2559   off_t output_size = this->output_local_symbol_count_ * sym_size;
2560   unsigned char* oview = NULL;
2561   if (output_size > 0)
2562     oview = of->get_output_view(symtab_off + this->local_symbol_offset_,
2563                                 output_size);
2564
2565   off_t dyn_output_size = this->output_local_dynsym_count_ * sym_size;
2566   unsigned char* dyn_oview = NULL;
2567   if (dyn_output_size > 0)
2568     dyn_oview = of->get_output_view(this->local_dynsym_offset_,
2569                                     dyn_output_size);
2570
2571   const Output_sections out_sections(this->output_sections());
2572
2573   gold_assert(this->local_values_.size() == loccount);
2574
2575   unsigned char* ov = oview;
2576   unsigned char* dyn_ov = dyn_oview;
2577   psyms += sym_size;
2578   for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
2579     {
2580       elfcpp::Sym<size, big_endian> isym(psyms);
2581
2582       Symbol_value<size>& lv(this->local_values_[i]);
2583
2584       bool is_ordinary;
2585       unsigned int st_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
2586                                                      &is_ordinary);
2587       if (is_ordinary)
2588         {
2589           gold_assert(st_shndx < out_sections.size());
2590           if (out_sections[st_shndx] == NULL)
2591             continue;
2592           st_shndx = out_sections[st_shndx]->out_shndx();
2593           if (st_shndx >= elfcpp::SHN_LORESERVE)
2594             {
2595               if (lv.has_output_symtab_entry())
2596                 symtab_xindex->add(lv.output_symtab_index(), st_shndx);
2597               if (lv.has_output_dynsym_entry())
2598                 dynsym_xindex->add(lv.output_dynsym_index(), st_shndx);
2599               st_shndx = elfcpp::SHN_XINDEX;
2600             }
2601         }
2602
2603       // Write the symbol to the output symbol table.
2604       if (lv.has_output_symtab_entry())
2605         {
2606           elfcpp::Sym_write<size, big_endian> osym(ov);
2607
2608           gold_assert(isym.get_st_name() < strtab_size);
2609           const char* name = pnames + isym.get_st_name();
2610           osym.put_st_name(sympool->get_offset(name));
2611           osym.put_st_value(this->local_values_[i].value(this, 0));
2612           osym.put_st_size(isym.get_st_size());
2613           osym.put_st_info(isym.get_st_info());
2614           osym.put_st_other(isym.get_st_other());
2615           osym.put_st_shndx(st_shndx);
2616
2617           ov += sym_size;
2618         }
2619
2620       // Write the symbol to the output dynamic symbol table.
2621       if (lv.has_output_dynsym_entry())
2622         {
2623           gold_assert(dyn_ov < dyn_oview + dyn_output_size);
2624           elfcpp::Sym_write<size, big_endian> osym(dyn_ov);
2625
2626           gold_assert(isym.get_st_name() < strtab_size);
2627           const char* name = pnames + isym.get_st_name();
2628           osym.put_st_name(dynpool->get_offset(name));
2629           osym.put_st_value(this->local_values_[i].value(this, 0));
2630           osym.put_st_size(isym.get_st_size());
2631           osym.put_st_info(isym.get_st_info());
2632           osym.put_st_other(isym.get_st_other());
2633           osym.put_st_shndx(st_shndx);
2634
2635           dyn_ov += sym_size;
2636         }
2637     }
2638
2639
2640   if (output_size > 0)
2641     {
2642       gold_assert(ov - oview == output_size);
2643       of->write_output_view(symtab_off + this->local_symbol_offset_,
2644                             output_size, oview);
2645     }
2646
2647   if (dyn_output_size > 0)
2648     {
2649       gold_assert(dyn_ov - dyn_oview == dyn_output_size);
2650       of->write_output_view(this->local_dynsym_offset_, dyn_output_size,
2651                             dyn_oview);
2652     }
2653 }
2654
2655 // Set *INFO to symbolic information about the offset OFFSET in the
2656 // section SHNDX.  Return true if we found something, false if we
2657 // found nothing.
2658
2659 template<int size, bool big_endian>
2660 bool
2661 Sized_relobj_file<size, big_endian>::get_symbol_location_info(
2662     unsigned int shndx,
2663     off_t offset,
2664     Symbol_location_info* info)
2665 {
2666   if (this->symtab_shndx_ == 0)
2667     return false;
2668
2669   section_size_type symbols_size;
2670   const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
2671                                                         &symbols_size,
2672                                                         false);
2673
2674   unsigned int symbol_names_shndx =
2675     this->adjust_shndx(this->section_link(this->symtab_shndx_));
2676   section_size_type names_size;
2677   const unsigned char* symbol_names_u =
2678     this->section_contents(symbol_names_shndx, &names_size, false);
2679   const char* symbol_names = reinterpret_cast<const char*>(symbol_names_u);
2680
2681   const int sym_size = This::sym_size;
2682   const size_t count = symbols_size / sym_size;
2683
2684   const unsigned char* p = symbols;
2685   for (size_t i = 0; i < count; ++i, p += sym_size)
2686     {
2687       elfcpp::Sym<size, big_endian> sym(p);
2688
2689       if (sym.get_st_type() == elfcpp::STT_FILE)
2690         {
2691           if (sym.get_st_name() >= names_size)
2692             info->source_file = "(invalid)";
2693           else
2694             info->source_file = symbol_names + sym.get_st_name();
2695           continue;
2696         }
2697
2698       bool is_ordinary;
2699       unsigned int st_shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
2700                                                      &is_ordinary);
2701       if (is_ordinary
2702           && st_shndx == shndx
2703           && static_cast<off_t>(sym.get_st_value()) <= offset
2704           && (static_cast<off_t>(sym.get_st_value() + sym.get_st_size())
2705               > offset))
2706         {
2707           info->enclosing_symbol_type = sym.get_st_type();
2708           if (sym.get_st_name() > names_size)
2709             info->enclosing_symbol_name = "(invalid)";
2710           else
2711             {
2712               info->enclosing_symbol_name = symbol_names + sym.get_st_name();
2713               if (parameters->options().do_demangle())
2714                 {
2715                   char* demangled_name = cplus_demangle(
2716                       info->enclosing_symbol_name.c_str(),
2717                       DMGL_ANSI | DMGL_PARAMS);
2718                   if (demangled_name != NULL)
2719                     {
2720                       info->enclosing_symbol_name.assign(demangled_name);
2721                       free(demangled_name);
2722                     }
2723                 }
2724             }
2725           return true;
2726         }
2727     }
2728
2729   return false;
2730 }
2731
2732 // Look for a kept section corresponding to the given discarded section,
2733 // and return its output address.  This is used only for relocations in
2734 // debugging sections.  If we can't find the kept section, return 0.
2735
2736 template<int size, bool big_endian>
2737 typename Sized_relobj_file<size, big_endian>::Address
2738 Sized_relobj_file<size, big_endian>::map_to_kept_section(
2739     unsigned int shndx,
2740     bool* found) const
2741 {
2742   Relobj* kept_object;
2743   unsigned int kept_shndx;
2744   if (this->get_kept_comdat_section(shndx, &kept_object, &kept_shndx))
2745     {
2746       Sized_relobj_file<size, big_endian>* kept_relobj =
2747         static_cast<Sized_relobj_file<size, big_endian>*>(kept_object);
2748       Output_section* os = kept_relobj->output_section(kept_shndx);
2749       Address offset = kept_relobj->get_output_section_offset(kept_shndx);
2750       if (os != NULL && offset != invalid_address)
2751         {
2752           *found = true;
2753           return os->address() + offset;
2754         }
2755     }
2756   *found = false;
2757   return 0;
2758 }
2759
2760 // Get symbol counts.
2761
2762 template<int size, bool big_endian>
2763 void
2764 Sized_relobj_file<size, big_endian>::do_get_global_symbol_counts(
2765     const Symbol_table*,
2766     size_t* defined,
2767     size_t* used) const
2768 {
2769   *defined = this->defined_count_;
2770   size_t count = 0;
2771   for (typename Symbols::const_iterator p = this->symbols_.begin();
2772        p != this->symbols_.end();
2773        ++p)
2774     if (*p != NULL
2775         && (*p)->source() == Symbol::FROM_OBJECT
2776         && (*p)->object() == this
2777         && (*p)->is_defined())
2778       ++count;
2779   *used = count;
2780 }
2781
2782 // Return a view of the decompressed contents of a section.  Set *PLEN
2783 // to the size.  Set *IS_NEW to true if the contents need to be freed
2784 // by the caller.
2785
2786 template<int size, bool big_endian>
2787 const unsigned char*
2788 Sized_relobj_file<size, big_endian>::do_decompressed_section_contents(
2789     unsigned int shndx,
2790     section_size_type* plen,
2791     bool* is_new)
2792 {
2793   section_size_type buffer_size;
2794   const unsigned char* buffer = this->do_section_contents(shndx, &buffer_size,
2795                                                           false);
2796
2797   if (this->compressed_sections_ == NULL)
2798     {
2799       *plen = buffer_size;
2800       *is_new = false;
2801       return buffer;
2802     }
2803
2804   Compressed_section_map::const_iterator p =
2805       this->compressed_sections_->find(shndx);
2806   if (p == this->compressed_sections_->end())
2807     {
2808       *plen = buffer_size;
2809       *is_new = false;
2810       return buffer;
2811     }
2812
2813   section_size_type uncompressed_size = p->second.size;
2814   if (p->second.contents != NULL)
2815     {
2816       *plen = uncompressed_size;
2817       *is_new = false;
2818       return p->second.contents;
2819     }
2820
2821   unsigned char* uncompressed_data = new unsigned char[uncompressed_size];
2822   if (!decompress_input_section(buffer,
2823                                 buffer_size,
2824                                 uncompressed_data,
2825                                 uncompressed_size))
2826     this->error(_("could not decompress section %s"),
2827                 this->do_section_name(shndx).c_str());
2828
2829   // We could cache the results in p->second.contents and store
2830   // false in *IS_NEW, but build_compressed_section_map() would
2831   // have done so if it had expected it to be profitable.  If
2832   // we reach this point, we expect to need the contents only
2833   // once in this pass.
2834   *plen = uncompressed_size;
2835   *is_new = true;
2836   return uncompressed_data;
2837 }
2838
2839 // Discard any buffers of uncompressed sections.  This is done
2840 // at the end of the Add_symbols task.
2841
2842 template<int size, bool big_endian>
2843 void
2844 Sized_relobj_file<size, big_endian>::do_discard_decompressed_sections()
2845 {
2846   if (this->compressed_sections_ == NULL)
2847     return;
2848
2849   for (Compressed_section_map::iterator p = this->compressed_sections_->begin();
2850        p != this->compressed_sections_->end();
2851        ++p)
2852     {
2853       if (p->second.contents != NULL)
2854         {
2855           delete[] p->second.contents;
2856           p->second.contents = NULL;
2857         }
2858     }
2859 }
2860
2861 // Input_objects methods.
2862
2863 // Add a regular relocatable object to the list.  Return false if this
2864 // object should be ignored.
2865
2866 bool
2867 Input_objects::add_object(Object* obj)
2868 {
2869   // Print the filename if the -t/--trace option is selected.
2870   if (parameters->options().trace())
2871     gold_info("%s", obj->name().c_str());
2872
2873   if (!obj->is_dynamic())
2874     this->relobj_list_.push_back(static_cast<Relobj*>(obj));
2875   else
2876     {
2877       // See if this is a duplicate SONAME.
2878       Dynobj* dynobj = static_cast<Dynobj*>(obj);
2879       const char* soname = dynobj->soname();
2880
2881       std::pair<Unordered_set<std::string>::iterator, bool> ins =
2882         this->sonames_.insert(soname);
2883       if (!ins.second)
2884         {
2885           // We have already seen a dynamic object with this soname.
2886           return false;
2887         }
2888
2889       this->dynobj_list_.push_back(dynobj);
2890     }
2891
2892   // Add this object to the cross-referencer if requested.
2893   if (parameters->options().user_set_print_symbol_counts()
2894       || parameters->options().cref())
2895     {
2896       if (this->cref_ == NULL)
2897         this->cref_ = new Cref();
2898       this->cref_->add_object(obj);
2899     }
2900
2901   return true;
2902 }
2903
2904 // For each dynamic object, record whether we've seen all of its
2905 // explicit dependencies.
2906
2907 void
2908 Input_objects::check_dynamic_dependencies() const
2909 {
2910   bool issued_copy_dt_needed_error = false;
2911   for (Dynobj_list::const_iterator p = this->dynobj_list_.begin();
2912        p != this->dynobj_list_.end();
2913        ++p)
2914     {
2915       const Dynobj::Needed& needed((*p)->needed());
2916       bool found_all = true;
2917       Dynobj::Needed::const_iterator pneeded;
2918       for (pneeded = needed.begin(); pneeded != needed.end(); ++pneeded)
2919         {
2920           if (this->sonames_.find(*pneeded) == this->sonames_.end())
2921             {
2922               found_all = false;
2923               break;
2924             }
2925         }
2926       (*p)->set_has_unknown_needed_entries(!found_all);
2927
2928       // --copy-dt-needed-entries aka --add-needed is a GNU ld option
2929       // that gold does not support.  However, they cause no trouble
2930       // unless there is a DT_NEEDED entry that we don't know about;
2931       // warn only in that case.
2932       if (!found_all
2933           && !issued_copy_dt_needed_error
2934           && (parameters->options().copy_dt_needed_entries()
2935               || parameters->options().add_needed()))
2936         {
2937           const char* optname;
2938           if (parameters->options().copy_dt_needed_entries())
2939             optname = "--copy-dt-needed-entries";
2940           else
2941             optname = "--add-needed";
2942           gold_error(_("%s is not supported but is required for %s in %s"),
2943                      optname, (*pneeded).c_str(), (*p)->name().c_str());
2944           issued_copy_dt_needed_error = true;
2945         }
2946     }
2947 }
2948
2949 // Start processing an archive.
2950
2951 void
2952 Input_objects::archive_start(Archive* archive)
2953 {
2954   if (parameters->options().user_set_print_symbol_counts()
2955       || parameters->options().cref())
2956     {
2957       if (this->cref_ == NULL)
2958         this->cref_ = new Cref();
2959       this->cref_->add_archive_start(archive);
2960     }
2961 }
2962
2963 // Stop processing an archive.
2964
2965 void
2966 Input_objects::archive_stop(Archive* archive)
2967 {
2968   if (parameters->options().user_set_print_symbol_counts()
2969       || parameters->options().cref())
2970     this->cref_->add_archive_stop(archive);
2971 }
2972
2973 // Print symbol counts
2974
2975 void
2976 Input_objects::print_symbol_counts(const Symbol_table* symtab) const
2977 {
2978   if (parameters->options().user_set_print_symbol_counts()
2979       && this->cref_ != NULL)
2980     this->cref_->print_symbol_counts(symtab);
2981 }
2982
2983 // Print a cross reference table.
2984
2985 void
2986 Input_objects::print_cref(const Symbol_table* symtab, FILE* f) const
2987 {
2988   if (parameters->options().cref() && this->cref_ != NULL)
2989     this->cref_->print_cref(symtab, f);
2990 }
2991
2992 // Relocate_info methods.
2993
2994 // Return a string describing the location of a relocation when file
2995 // and lineno information is not available.  This is only used in
2996 // error messages.
2997
2998 template<int size, bool big_endian>
2999 std::string
3000 Relocate_info<size, big_endian>::location(size_t, off_t offset) const
3001 {
3002   Sized_dwarf_line_info<size, big_endian> line_info(this->object);
3003   std::string ret = line_info.addr2line(this->data_shndx, offset, NULL);
3004   if (!ret.empty())
3005     return ret;
3006
3007   ret = this->object->name();
3008
3009   Symbol_location_info info;
3010   if (this->object->get_symbol_location_info(this->data_shndx, offset, &info))
3011     {
3012       if (!info.source_file.empty())
3013         {
3014           ret += ":";
3015           ret += info.source_file;
3016         }
3017       ret += ":";
3018       if (info.enclosing_symbol_type == elfcpp::STT_FUNC)
3019         ret += _("function ");
3020       ret += info.enclosing_symbol_name;
3021       return ret;
3022     }
3023
3024   ret += "(";
3025   ret += this->object->section_name(this->data_shndx);
3026   char buf[100];
3027   snprintf(buf, sizeof buf, "+0x%lx)", static_cast<long>(offset));
3028   ret += buf;
3029   return ret;
3030 }
3031
3032 } // End namespace gold.
3033
3034 namespace
3035 {
3036
3037 using namespace gold;
3038
3039 // Read an ELF file with the header and return the appropriate
3040 // instance of Object.
3041
3042 template<int size, bool big_endian>
3043 Object*
3044 make_elf_sized_object(const std::string& name, Input_file* input_file,
3045                       off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr,
3046                       bool* punconfigured)
3047 {
3048   Target* target = select_target(input_file, offset,
3049                                  ehdr.get_e_machine(), size, big_endian,
3050                                  ehdr.get_e_ident()[elfcpp::EI_OSABI],
3051                                  ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
3052   if (target == NULL)
3053     gold_fatal(_("%s: unsupported ELF machine number %d"),
3054                name.c_str(), ehdr.get_e_machine());
3055
3056   if (!parameters->target_valid())
3057     set_parameters_target(target);
3058   else if (target != &parameters->target())
3059     {
3060       if (punconfigured != NULL)
3061         *punconfigured = true;
3062       else
3063         gold_error(_("%s: incompatible target"), name.c_str());
3064       return NULL;
3065     }
3066
3067   return target->make_elf_object<size, big_endian>(name, input_file, offset,
3068                                                    ehdr);
3069 }
3070
3071 } // End anonymous namespace.
3072
3073 namespace gold
3074 {
3075
3076 // Return whether INPUT_FILE is an ELF object.
3077
3078 bool
3079 is_elf_object(Input_file* input_file, off_t offset,
3080               const unsigned char** start, int* read_size)
3081 {
3082   off_t filesize = input_file->file().filesize();
3083   int want = elfcpp::Elf_recognizer::max_header_size;
3084   if (filesize - offset < want)
3085     want = filesize - offset;
3086
3087   const unsigned char* p = input_file->file().get_view(offset, 0, want,
3088                                                        true, false);
3089   *start = p;
3090   *read_size = want;
3091
3092   return elfcpp::Elf_recognizer::is_elf_file(p, want);
3093 }
3094
3095 // Read an ELF file and return the appropriate instance of Object.
3096
3097 Object*
3098 make_elf_object(const std::string& name, Input_file* input_file, off_t offset,
3099                 const unsigned char* p, section_offset_type bytes,
3100                 bool* punconfigured)
3101 {
3102   if (punconfigured != NULL)
3103     *punconfigured = false;
3104
3105   std::string error;
3106   bool big_endian = false;
3107   int size = 0;
3108   if (!elfcpp::Elf_recognizer::is_valid_header(p, bytes, &size,
3109                                                &big_endian, &error))
3110     {
3111       gold_error(_("%s: %s"), name.c_str(), error.c_str());
3112       return NULL;
3113     }
3114
3115   if (size == 32)
3116     {
3117       if (big_endian)
3118         {
3119 #ifdef HAVE_TARGET_32_BIG
3120           elfcpp::Ehdr<32, true> ehdr(p);
3121           return make_elf_sized_object<32, true>(name, input_file,
3122                                                  offset, ehdr, punconfigured);
3123 #else
3124           if (punconfigured != NULL)
3125             *punconfigured = true;
3126           else
3127             gold_error(_("%s: not configured to support "
3128                          "32-bit big-endian object"),
3129                        name.c_str());
3130           return NULL;
3131 #endif
3132         }
3133       else
3134         {
3135 #ifdef HAVE_TARGET_32_LITTLE
3136           elfcpp::Ehdr<32, false> ehdr(p);
3137           return make_elf_sized_object<32, false>(name, input_file,
3138                                                   offset, ehdr, punconfigured);
3139 #else
3140           if (punconfigured != NULL)
3141             *punconfigured = true;
3142           else
3143             gold_error(_("%s: not configured to support "
3144                          "32-bit little-endian object"),
3145                        name.c_str());
3146           return NULL;
3147 #endif
3148         }
3149     }
3150   else if (size == 64)
3151     {
3152       if (big_endian)
3153         {
3154 #ifdef HAVE_TARGET_64_BIG
3155           elfcpp::Ehdr<64, true> ehdr(p);
3156           return make_elf_sized_object<64, true>(name, input_file,
3157                                                  offset, ehdr, punconfigured);
3158 #else
3159           if (punconfigured != NULL)
3160             *punconfigured = true;
3161           else
3162             gold_error(_("%s: not configured to support "
3163                          "64-bit big-endian object"),
3164                        name.c_str());
3165           return NULL;
3166 #endif
3167         }
3168       else
3169         {
3170 #ifdef HAVE_TARGET_64_LITTLE
3171           elfcpp::Ehdr<64, false> ehdr(p);
3172           return make_elf_sized_object<64, false>(name, input_file,
3173                                                   offset, ehdr, punconfigured);
3174 #else
3175           if (punconfigured != NULL)
3176             *punconfigured = true;
3177           else
3178             gold_error(_("%s: not configured to support "
3179                          "64-bit little-endian object"),
3180                        name.c_str());
3181           return NULL;
3182 #endif
3183         }
3184     }
3185   else
3186     gold_unreachable();
3187 }
3188
3189 // Instantiate the templates we need.
3190
3191 #ifdef HAVE_TARGET_32_LITTLE
3192 template
3193 void
3194 Object::read_section_data<32, false>(elfcpp::Elf_file<32, false, Object>*,
3195                                      Read_symbols_data*);
3196 template
3197 const unsigned char*
3198 Object::find_shdr<32,false>(const unsigned char*, const char*, const char*,
3199                             section_size_type, const unsigned char*) const;
3200 #endif
3201
3202 #ifdef HAVE_TARGET_32_BIG
3203 template
3204 void
3205 Object::read_section_data<32, true>(elfcpp::Elf_file<32, true, Object>*,
3206                                     Read_symbols_data*);
3207 template
3208 const unsigned char*
3209 Object::find_shdr<32,true>(const unsigned char*, const char*, const char*,
3210                            section_size_type, const unsigned char*) const;
3211 #endif
3212
3213 #ifdef HAVE_TARGET_64_LITTLE
3214 template
3215 void
3216 Object::read_section_data<64, false>(elfcpp::Elf_file<64, false, Object>*,
3217                                      Read_symbols_data*);
3218 template
3219 const unsigned char*
3220 Object::find_shdr<64,false>(const unsigned char*, const char*, const char*,
3221                             section_size_type, const unsigned char*) const;
3222 #endif
3223
3224 #ifdef HAVE_TARGET_64_BIG
3225 template
3226 void
3227 Object::read_section_data<64, true>(elfcpp::Elf_file<64, true, Object>*,
3228                                     Read_symbols_data*);
3229 template
3230 const unsigned char*
3231 Object::find_shdr<64,true>(const unsigned char*, const char*, const char*,
3232                            section_size_type, const unsigned char*) const;
3233 #endif
3234
3235 #ifdef HAVE_TARGET_32_LITTLE
3236 template
3237 class Sized_relobj<32, false>;
3238
3239 template
3240 class Sized_relobj_file<32, false>;
3241 #endif
3242
3243 #ifdef HAVE_TARGET_32_BIG
3244 template
3245 class Sized_relobj<32, true>;
3246
3247 template
3248 class Sized_relobj_file<32, true>;
3249 #endif
3250
3251 #ifdef HAVE_TARGET_64_LITTLE
3252 template
3253 class Sized_relobj<64, false>;
3254
3255 template
3256 class Sized_relobj_file<64, false>;
3257 #endif
3258
3259 #ifdef HAVE_TARGET_64_BIG
3260 template
3261 class Sized_relobj<64, true>;
3262
3263 template
3264 class Sized_relobj_file<64, true>;
3265 #endif
3266
3267 #ifdef HAVE_TARGET_32_LITTLE
3268 template
3269 struct Relocate_info<32, false>;
3270 #endif
3271
3272 #ifdef HAVE_TARGET_32_BIG
3273 template
3274 struct Relocate_info<32, true>;
3275 #endif
3276
3277 #ifdef HAVE_TARGET_64_LITTLE
3278 template
3279 struct Relocate_info<64, false>;
3280 #endif
3281
3282 #ifdef HAVE_TARGET_64_BIG
3283 template
3284 struct Relocate_info<64, true>;
3285 #endif
3286
3287 #ifdef HAVE_TARGET_32_LITTLE
3288 template
3289 void
3290 Xindex::initialize_symtab_xindex<32, false>(Object*, unsigned int);
3291
3292 template
3293 void
3294 Xindex::read_symtab_xindex<32, false>(Object*, unsigned int,
3295                                       const unsigned char*);
3296 #endif
3297
3298 #ifdef HAVE_TARGET_32_BIG
3299 template
3300 void
3301 Xindex::initialize_symtab_xindex<32, true>(Object*, unsigned int);
3302
3303 template
3304 void
3305 Xindex::read_symtab_xindex<32, true>(Object*, unsigned int,
3306                                      const unsigned char*);
3307 #endif
3308
3309 #ifdef HAVE_TARGET_64_LITTLE
3310 template
3311 void
3312 Xindex::initialize_symtab_xindex<64, false>(Object*, unsigned int);
3313
3314 template
3315 void
3316 Xindex::read_symtab_xindex<64, false>(Object*, unsigned int,
3317                                       const unsigned char*);
3318 #endif
3319
3320 #ifdef HAVE_TARGET_64_BIG
3321 template
3322 void
3323 Xindex::initialize_symtab_xindex<64, true>(Object*, unsigned int);
3324
3325 template
3326 void
3327 Xindex::read_symtab_xindex<64, true>(Object*, unsigned int,
3328                                      const unsigned char*);
3329 #endif
3330
3331 } // End namespace gold.