1 // object.cc -- support for an object file for linking in gold
3 // Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
29 #include "libiberty.h"
32 #include "target-select.h"
33 #include "dwarf_reader.h"
48 // Initialize the symtab_xindex_ array. Find the SHT_SYMTAB_SHNDX
49 // section and read it in. SYMTAB_SHNDX is the index of the symbol
50 // table we care about.
52 template<int size, bool big_endian>
54 Xindex::initialize_symtab_xindex(Object* object, unsigned int symtab_shndx)
56 if (!this->symtab_xindex_.empty())
59 gold_assert(symtab_shndx != 0);
61 // Look through the sections in reverse order, on the theory that it
62 // is more likely to be near the end than the beginning.
63 unsigned int i = object->shnum();
67 if (object->section_type(i) == elfcpp::SHT_SYMTAB_SHNDX
68 && this->adjust_shndx(object->section_link(i)) == symtab_shndx)
70 this->read_symtab_xindex<size, big_endian>(object, i, NULL);
75 object->error(_("missing SHT_SYMTAB_SHNDX section"));
78 // Read in the symtab_xindex_ array, given the section index of the
79 // SHT_SYMTAB_SHNDX section. If PSHDRS is not NULL, it points at the
82 template<int size, bool big_endian>
84 Xindex::read_symtab_xindex(Object* object, unsigned int xindex_shndx,
85 const unsigned char* pshdrs)
87 section_size_type bytecount;
88 const unsigned char* contents;
90 contents = object->section_contents(xindex_shndx, &bytecount, false);
93 const unsigned char* p = (pshdrs
95 * elfcpp::Elf_sizes<size>::shdr_size));
96 typename elfcpp::Shdr<size, big_endian> shdr(p);
97 bytecount = convert_to_section_size_type(shdr.get_sh_size());
98 contents = object->get_view(shdr.get_sh_offset(), bytecount, true, false);
101 gold_assert(this->symtab_xindex_.empty());
102 this->symtab_xindex_.reserve(bytecount / 4);
103 for (section_size_type i = 0; i < bytecount; i += 4)
105 unsigned int shndx = elfcpp::Swap<32, big_endian>::readval(contents + i);
106 // We preadjust the section indexes we save.
107 this->symtab_xindex_.push_back(this->adjust_shndx(shndx));
111 // Symbol symndx has a section of SHN_XINDEX; return the real section
115 Xindex::sym_xindex_to_shndx(Object* object, unsigned int symndx)
117 if (symndx >= this->symtab_xindex_.size())
119 object->error(_("symbol %u out of range for SHT_SYMTAB_SHNDX section"),
121 return elfcpp::SHN_UNDEF;
123 unsigned int shndx = this->symtab_xindex_[symndx];
124 if (shndx < elfcpp::SHN_LORESERVE || shndx >= object->shnum())
126 object->error(_("extended index for symbol %u out of range: %u"),
128 return elfcpp::SHN_UNDEF;
135 // Set the target based on fields in the ELF file header.
138 Object::set_target(int machine, int size, bool big_endian, int osabi,
141 Target* target = select_target(machine, size, big_endian, osabi, abiversion);
143 gold_fatal(_("%s: unsupported ELF machine number %d"),
144 this->name().c_str(), machine);
145 this->target_ = target;
148 // Report an error for this object file. This is used by the
149 // elfcpp::Elf_file interface, and also called by the Object code
153 Object::error(const char* format, ...) const
156 va_start(args, format);
158 if (vasprintf(&buf, format, args) < 0)
161 gold_error(_("%s: %s"), this->name().c_str(), buf);
165 // Return a view of the contents of a section.
168 Object::section_contents(unsigned int shndx, section_size_type* plen,
171 Location loc(this->do_section_contents(shndx));
172 *plen = convert_to_section_size_type(loc.data_size);
173 return this->get_view(loc.file_offset, *plen, true, cache);
176 // Read the section data into SD. This is code common to Sized_relobj
177 // and Sized_dynobj, so we put it into Object.
179 template<int size, bool big_endian>
181 Object::read_section_data(elfcpp::Elf_file<size, big_endian, Object>* elf_file,
182 Read_symbols_data* sd)
184 const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
186 // Read the section headers.
187 const off_t shoff = elf_file->shoff();
188 const unsigned int shnum = this->shnum();
189 sd->section_headers = this->get_lasting_view(shoff, shnum * shdr_size,
192 // Read the section names.
193 const unsigned char* pshdrs = sd->section_headers->data();
194 const unsigned char* pshdrnames = pshdrs + elf_file->shstrndx() * shdr_size;
195 typename elfcpp::Shdr<size, big_endian> shdrnames(pshdrnames);
197 if (shdrnames.get_sh_type() != elfcpp::SHT_STRTAB)
198 this->error(_("section name section has wrong type: %u"),
199 static_cast<unsigned int>(shdrnames.get_sh_type()));
201 sd->section_names_size =
202 convert_to_section_size_type(shdrnames.get_sh_size());
203 sd->section_names = this->get_lasting_view(shdrnames.get_sh_offset(),
204 sd->section_names_size, false,
208 // If NAME is the name of a special .gnu.warning section, arrange for
209 // the warning to be issued. SHNDX is the section index. Return
210 // whether it is a warning section.
213 Object::handle_gnu_warning_section(const char* name, unsigned int shndx,
214 Symbol_table* symtab)
216 const char warn_prefix[] = ".gnu.warning.";
217 const int warn_prefix_len = sizeof warn_prefix - 1;
218 if (strncmp(name, warn_prefix, warn_prefix_len) == 0)
220 // Read the section contents to get the warning text. It would
221 // be nicer if we only did this if we have to actually issue a
222 // warning. Unfortunately, warnings are issued as we relocate
223 // sections. That means that we can not lock the object then,
224 // as we might try to issue the same warning multiple times
226 section_size_type len;
227 const unsigned char* contents = this->section_contents(shndx, &len,
229 std::string warning(reinterpret_cast<const char*>(contents), len);
230 symtab->add_warning(name + warn_prefix_len, this, warning);
238 // To copy the symbols data read from the file to a local data structure.
239 // This function is called from do_layout only while doing garbage
243 Relobj::copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd,
244 unsigned int section_header_size)
246 gc_sd->section_headers_data =
247 new unsigned char[(section_header_size)];
248 memcpy(gc_sd->section_headers_data, sd->section_headers->data(),
249 section_header_size);
250 gc_sd->section_names_data =
251 new unsigned char[sd->section_names_size];
252 memcpy(gc_sd->section_names_data, sd->section_names->data(),
253 sd->section_names_size);
254 gc_sd->section_names_size = sd->section_names_size;
255 if (sd->symbols != NULL)
257 gc_sd->symbols_data =
258 new unsigned char[sd->symbols_size];
259 memcpy(gc_sd->symbols_data, sd->symbols->data(),
264 gc_sd->symbols_data = NULL;
266 gc_sd->symbols_size = sd->symbols_size;
267 gc_sd->external_symbols_offset = sd->external_symbols_offset;
268 if (sd->symbol_names != NULL)
270 gc_sd->symbol_names_data =
271 new unsigned char[sd->symbol_names_size];
272 memcpy(gc_sd->symbol_names_data, sd->symbol_names->data(),
273 sd->symbol_names_size);
277 gc_sd->symbol_names_data = NULL;
279 gc_sd->symbol_names_size = sd->symbol_names_size;
282 // This function determines if a particular section name must be included
283 // in the link. This is used during garbage collection to determine the
284 // roots of the worklist.
287 Relobj::is_section_name_included(const char* name)
289 if (is_prefix_of(".ctors", name)
290 || is_prefix_of(".dtors", name)
291 || is_prefix_of(".note", name)
292 || is_prefix_of(".init", name)
293 || is_prefix_of(".fini", name)
294 || is_prefix_of(".gcc_except_table", name)
295 || is_prefix_of(".jcr", name)
296 || is_prefix_of(".preinit_array", name)
297 || (is_prefix_of(".text", name)
298 && strstr(name, "personality"))
299 || (is_prefix_of(".data", name)
300 && strstr(name, "personality"))
301 || (is_prefix_of(".gnu.linkonce.d", name) &&
302 strstr(name, "personality")))
309 // Class Sized_relobj.
311 template<int size, bool big_endian>
312 Sized_relobj<size, big_endian>::Sized_relobj(
313 const std::string& name,
314 Input_file* input_file,
316 const elfcpp::Ehdr<size, big_endian>& ehdr)
317 : Relobj(name, input_file, offset),
318 elf_file_(this, ehdr),
320 local_symbol_count_(0),
321 output_local_symbol_count_(0),
322 output_local_dynsym_count_(0),
325 local_symbol_offset_(0),
326 local_dynsym_offset_(0),
328 local_got_offsets_(),
329 kept_comdat_sections_(),
335 template<int size, bool big_endian>
336 Sized_relobj<size, big_endian>::~Sized_relobj()
340 // Set up an object file based on the file header. This sets up the
341 // target and reads the section information.
343 template<int size, bool big_endian>
345 Sized_relobj<size, big_endian>::setup(
346 const elfcpp::Ehdr<size, big_endian>& ehdr)
348 this->set_target(ehdr.get_e_machine(), size, big_endian,
349 ehdr.get_e_ident()[elfcpp::EI_OSABI],
350 ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
352 const unsigned int shnum = this->elf_file_.shnum();
353 this->set_shnum(shnum);
356 // Find the SHT_SYMTAB section, given the section headers. The ELF
357 // standard says that maybe in the future there can be more than one
358 // SHT_SYMTAB section. Until somebody figures out how that could
359 // work, we assume there is only one.
361 template<int size, bool big_endian>
363 Sized_relobj<size, big_endian>::find_symtab(const unsigned char* pshdrs)
365 const unsigned int shnum = this->shnum();
366 this->symtab_shndx_ = 0;
369 // Look through the sections in reverse order, since gas tends
370 // to put the symbol table at the end.
371 const unsigned char* p = pshdrs + shnum * This::shdr_size;
372 unsigned int i = shnum;
373 unsigned int xindex_shndx = 0;
374 unsigned int xindex_link = 0;
378 p -= This::shdr_size;
379 typename This::Shdr shdr(p);
380 if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB)
382 this->symtab_shndx_ = i;
383 if (xindex_shndx > 0 && xindex_link == i)
386 new Xindex(this->elf_file_.large_shndx_offset());
387 xindex->read_symtab_xindex<size, big_endian>(this,
390 this->set_xindex(xindex);
395 // Try to pick up the SHT_SYMTAB_SHNDX section, if there is
396 // one. This will work if it follows the SHT_SYMTAB
398 if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX)
401 xindex_link = this->adjust_shndx(shdr.get_sh_link());
407 // Return the Xindex structure to use for object with lots of
410 template<int size, bool big_endian>
412 Sized_relobj<size, big_endian>::do_initialize_xindex()
414 gold_assert(this->symtab_shndx_ != -1U);
415 Xindex* xindex = new Xindex(this->elf_file_.large_shndx_offset());
416 xindex->initialize_symtab_xindex<size, big_endian>(this, this->symtab_shndx_);
420 // Return whether SHDR has the right type and flags to be a GNU
421 // .eh_frame section.
423 template<int size, bool big_endian>
425 Sized_relobj<size, big_endian>::check_eh_frame_flags(
426 const elfcpp::Shdr<size, big_endian>* shdr) const
428 return (shdr->get_sh_type() == elfcpp::SHT_PROGBITS
429 && (shdr->get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
432 // Return whether there is a GNU .eh_frame section, given the section
433 // headers and the section names.
435 template<int size, bool big_endian>
437 Sized_relobj<size, big_endian>::find_eh_frame(
438 const unsigned char* pshdrs,
440 section_size_type names_size) const
442 const unsigned int shnum = this->shnum();
443 const unsigned char* p = pshdrs + This::shdr_size;
444 for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
446 typename This::Shdr shdr(p);
447 if (this->check_eh_frame_flags(&shdr))
449 if (shdr.get_sh_name() >= names_size)
451 this->error(_("bad section name offset for section %u: %lu"),
452 i, static_cast<unsigned long>(shdr.get_sh_name()));
456 const char* name = names + shdr.get_sh_name();
457 if (strcmp(name, ".eh_frame") == 0)
464 // Read the sections and symbols from an object file.
466 template<int size, bool big_endian>
468 Sized_relobj<size, big_endian>::do_read_symbols(Read_symbols_data* sd)
470 this->read_section_data(&this->elf_file_, sd);
472 const unsigned char* const pshdrs = sd->section_headers->data();
474 this->find_symtab(pshdrs);
476 const unsigned char* namesu = sd->section_names->data();
477 const char* names = reinterpret_cast<const char*>(namesu);
478 if (memmem(names, sd->section_names_size, ".eh_frame", 10) != NULL)
480 if (this->find_eh_frame(pshdrs, names, sd->section_names_size))
481 this->has_eh_frame_ = true;
485 sd->symbols_size = 0;
486 sd->external_symbols_offset = 0;
487 sd->symbol_names = NULL;
488 sd->symbol_names_size = 0;
490 if (this->symtab_shndx_ == 0)
492 // No symbol table. Weird but legal.
496 // Get the symbol table section header.
497 typename This::Shdr symtabshdr(pshdrs
498 + this->symtab_shndx_ * This::shdr_size);
499 gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
501 // If this object has a .eh_frame section, we need all the symbols.
502 // Otherwise we only need the external symbols. While it would be
503 // simpler to just always read all the symbols, I've seen object
504 // files with well over 2000 local symbols, which for a 64-bit
505 // object file format is over 5 pages that we don't need to read
508 const int sym_size = This::sym_size;
509 const unsigned int loccount = symtabshdr.get_sh_info();
510 this->local_symbol_count_ = loccount;
511 this->local_values_.resize(loccount);
512 section_offset_type locsize = loccount * sym_size;
513 off_t dataoff = symtabshdr.get_sh_offset();
514 section_size_type datasize =
515 convert_to_section_size_type(symtabshdr.get_sh_size());
516 off_t extoff = dataoff + locsize;
517 section_size_type extsize = datasize - locsize;
519 off_t readoff = this->has_eh_frame_ ? dataoff : extoff;
520 section_size_type readsize = this->has_eh_frame_ ? datasize : extsize;
524 // No external symbols. Also weird but also legal.
528 File_view* fvsymtab = this->get_lasting_view(readoff, readsize, true, false);
530 // Read the section header for the symbol names.
531 unsigned int strtab_shndx = this->adjust_shndx(symtabshdr.get_sh_link());
532 if (strtab_shndx >= this->shnum())
534 this->error(_("invalid symbol table name index: %u"), strtab_shndx);
537 typename This::Shdr strtabshdr(pshdrs + strtab_shndx * This::shdr_size);
538 if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB)
540 this->error(_("symbol table name section has wrong type: %u"),
541 static_cast<unsigned int>(strtabshdr.get_sh_type()));
545 // Read the symbol names.
546 File_view* fvstrtab = this->get_lasting_view(strtabshdr.get_sh_offset(),
547 strtabshdr.get_sh_size(),
550 sd->symbols = fvsymtab;
551 sd->symbols_size = readsize;
552 sd->external_symbols_offset = this->has_eh_frame_ ? locsize : 0;
553 sd->symbol_names = fvstrtab;
554 sd->symbol_names_size =
555 convert_to_section_size_type(strtabshdr.get_sh_size());
558 // Return the section index of symbol SYM. Set *VALUE to its value in
559 // the object file. Set *IS_ORDINARY if this is an ordinary section
560 // index. not a special cod between SHN_LORESERVE and SHN_HIRESERVE.
561 // Note that for a symbol which is not defined in this object file,
562 // this will set *VALUE to 0 and return SHN_UNDEF; it will not return
563 // the final value of the symbol in the link.
565 template<int size, bool big_endian>
567 Sized_relobj<size, big_endian>::symbol_section_and_value(unsigned int sym,
571 section_size_type symbols_size;
572 const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
576 const size_t count = symbols_size / This::sym_size;
577 gold_assert(sym < count);
579 elfcpp::Sym<size, big_endian> elfsym(symbols + sym * This::sym_size);
580 *value = elfsym.get_st_value();
582 return this->adjust_sym_shndx(sym, elfsym.get_st_shndx(), is_ordinary);
585 // Return whether to include a section group in the link. LAYOUT is
586 // used to keep track of which section groups we have already seen.
587 // INDEX is the index of the section group and SHDR is the section
588 // header. If we do not want to include this group, we set bits in
589 // OMIT for each section which should be discarded.
591 template<int size, bool big_endian>
593 Sized_relobj<size, big_endian>::include_section_group(
594 Symbol_table* symtab,
598 const unsigned char* shdrs,
599 const char* section_names,
600 section_size_type section_names_size,
601 std::vector<bool>* omit)
603 // Read the section contents.
604 typename This::Shdr shdr(shdrs + index * This::shdr_size);
605 const unsigned char* pcon = this->get_view(shdr.get_sh_offset(),
606 shdr.get_sh_size(), true, false);
607 const elfcpp::Elf_Word* pword =
608 reinterpret_cast<const elfcpp::Elf_Word*>(pcon);
610 // The first word contains flags. We only care about COMDAT section
611 // groups. Other section groups are always included in the link
612 // just like ordinary sections.
613 elfcpp::Elf_Word flags = elfcpp::Swap<32, big_endian>::readval(pword);
615 // Look up the group signature, which is the name of a symbol. This
616 // is a lot of effort to go to to read a string. Why didn't they
617 // just have the group signature point into the string table, rather
618 // than indirect through a symbol?
620 // Get the appropriate symbol table header (this will normally be
621 // the single SHT_SYMTAB section, but in principle it need not be).
622 const unsigned int link = this->adjust_shndx(shdr.get_sh_link());
623 typename This::Shdr symshdr(this, this->elf_file_.section_header(link));
625 // Read the symbol table entry.
626 unsigned int symndx = shdr.get_sh_info();
627 if (symndx >= symshdr.get_sh_size() / This::sym_size)
629 this->error(_("section group %u info %u out of range"),
633 off_t symoff = symshdr.get_sh_offset() + symndx * This::sym_size;
634 const unsigned char* psym = this->get_view(symoff, This::sym_size, true,
636 elfcpp::Sym<size, big_endian> sym(psym);
638 // Read the symbol table names.
639 section_size_type symnamelen;
640 const unsigned char* psymnamesu;
641 psymnamesu = this->section_contents(this->adjust_shndx(symshdr.get_sh_link()),
643 const char* psymnames = reinterpret_cast<const char*>(psymnamesu);
645 // Get the section group signature.
646 if (sym.get_st_name() >= symnamelen)
648 this->error(_("symbol %u name offset %u out of range"),
649 symndx, sym.get_st_name());
653 std::string signature(psymnames + sym.get_st_name());
655 // It seems that some versions of gas will create a section group
656 // associated with a section symbol, and then fail to give a name to
657 // the section symbol. In such a case, use the name of the section.
658 if (signature[0] == '\0' && sym.get_st_type() == elfcpp::STT_SECTION)
661 unsigned int sym_shndx = this->adjust_sym_shndx(symndx,
664 if (!is_ordinary || sym_shndx >= this->shnum())
666 this->error(_("symbol %u invalid section index %u"),
670 typename This::Shdr member_shdr(shdrs + sym_shndx * This::shdr_size);
671 if (member_shdr.get_sh_name() < section_names_size)
672 signature = section_names + member_shdr.get_sh_name();
675 // Record this section group in the layout, and see whether we've already
676 // seen one with the same signature.
677 bool include_group = ((flags & elfcpp::GRP_COMDAT) == 0
678 || layout->add_comdat(this, index, signature, true));
680 Sized_relobj<size, big_endian>* kept_object = NULL;
681 Comdat_group* kept_group = NULL;
685 // This group is being discarded. Find the object and group
686 // that was kept in its place.
687 unsigned int kept_group_index = 0;
688 Relobj* kept_relobj = layout->find_kept_object(signature,
690 kept_object = static_cast<Sized_relobj<size, big_endian>*>(kept_relobj);
691 if (kept_object != NULL)
692 kept_group = kept_object->find_comdat_group(kept_group_index);
694 else if (flags & elfcpp::GRP_COMDAT)
696 // This group is being kept. Create the table to map section names
697 // to section indexes and add it to the table of groups.
698 kept_group = new Comdat_group();
699 this->add_comdat_group(index, kept_group);
702 size_t count = shdr.get_sh_size() / sizeof(elfcpp::Elf_Word);
704 std::vector<unsigned int> shndxes;
705 bool relocate_group = include_group && parameters->options().relocatable();
707 shndxes.reserve(count - 1);
709 for (size_t i = 1; i < count; ++i)
711 elfcpp::Elf_Word secnum =
712 this->adjust_shndx(elfcpp::Swap<32, big_endian>::readval(pword + i));
715 shndxes.push_back(secnum);
717 if (secnum >= this->shnum())
719 this->error(_("section %u in section group %u out of range"),
724 // Check for an earlier section number, since we're going to get
725 // it wrong--we may have already decided to include the section.
727 this->error(_("invalid section group %u refers to earlier section %u"),
730 // Get the name of the member section.
731 typename This::Shdr member_shdr(shdrs + secnum * This::shdr_size);
732 if (member_shdr.get_sh_name() >= section_names_size)
734 // This is an error, but it will be diagnosed eventually
735 // in do_layout, so we don't need to do anything here but
739 std::string mname(section_names + member_shdr.get_sh_name());
743 (*omit)[secnum] = true;
744 if (kept_group != NULL)
746 // Find the corresponding kept section, and store that info
747 // in the discarded section table.
748 Comdat_group::const_iterator p = kept_group->find(mname);
749 if (p != kept_group->end())
751 Kept_comdat_section* kept =
752 new Kept_comdat_section(kept_object, p->second);
753 this->set_kept_comdat_section(secnum, kept);
757 else if (flags & elfcpp::GRP_COMDAT)
759 // Add the section to the kept group table.
760 gold_assert(kept_group != NULL);
761 kept_group->insert(std::make_pair(mname, secnum));
766 layout->layout_group(symtab, this, index, name, signature.c_str(),
767 shdr, flags, &shndxes);
769 return include_group;
772 // Whether to include a linkonce section in the link. NAME is the
773 // name of the section and SHDR is the section header.
775 // Linkonce sections are a GNU extension implemented in the original
776 // GNU linker before section groups were defined. The semantics are
777 // that we only include one linkonce section with a given name. The
778 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
779 // where T is the type of section and SYMNAME is the name of a symbol.
780 // In an attempt to make linkonce sections interact well with section
781 // groups, we try to identify SYMNAME and use it like a section group
782 // signature. We want to block section groups with that signature,
783 // but not other linkonce sections with that signature. We also use
784 // the full name of the linkonce section as a normal section group
787 template<int size, bool big_endian>
789 Sized_relobj<size, big_endian>::include_linkonce_section(
793 const elfcpp::Shdr<size, big_endian>&)
795 // In general the symbol name we want will be the string following
796 // the last '.'. However, we have to handle the case of
797 // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
798 // some versions of gcc. So we use a heuristic: if the name starts
799 // with ".gnu.linkonce.t.", we use everything after that. Otherwise
800 // we look for the last '.'. We can't always simply skip
801 // ".gnu.linkonce.X", because we have to deal with cases like
802 // ".gnu.linkonce.d.rel.ro.local".
803 const char* const linkonce_t = ".gnu.linkonce.t.";
805 if (strncmp(name, linkonce_t, strlen(linkonce_t)) == 0)
806 symname = name + strlen(linkonce_t);
808 symname = strrchr(name, '.') + 1;
809 std::string sig1(symname);
810 std::string sig2(name);
811 bool include1 = layout->add_comdat(this, index, sig1, false);
812 bool include2 = layout->add_comdat(this, index, sig2, true);
816 // The section is being discarded on the basis of its section
817 // name (i.e., the kept section was also a linkonce section).
818 // In this case, the section index stored with the layout object
819 // is the linkonce section that was kept.
820 unsigned int kept_group_index = 0;
821 Relobj* kept_relobj = layout->find_kept_object(sig2, &kept_group_index);
822 if (kept_relobj != NULL)
824 Sized_relobj<size, big_endian>* kept_object
825 = static_cast<Sized_relobj<size, big_endian>*>(kept_relobj);
826 Kept_comdat_section* kept =
827 new Kept_comdat_section(kept_object, kept_group_index);
828 this->set_kept_comdat_section(index, kept);
833 // The section is being discarded on the basis of its symbol
834 // name. This means that the corresponding kept section was
835 // part of a comdat group, and it will be difficult to identify
836 // the specific section within that group that corresponds to
837 // this linkonce section. We'll handle the simple case where
838 // the group has only one member section. Otherwise, it's not
840 unsigned int kept_group_index = 0;
841 Relobj* kept_relobj = layout->find_kept_object(sig1, &kept_group_index);
842 if (kept_relobj != NULL)
844 Sized_relobj<size, big_endian>* kept_object =
845 static_cast<Sized_relobj<size, big_endian>*>(kept_relobj);
846 Comdat_group* kept_group =
847 kept_object->find_comdat_group(kept_group_index);
848 if (kept_group != NULL && kept_group->size() == 1)
850 Comdat_group::const_iterator p = kept_group->begin();
851 gold_assert(p != kept_group->end());
852 Kept_comdat_section* kept =
853 new Kept_comdat_section(kept_object, p->second);
854 this->set_kept_comdat_section(index, kept);
859 return include1 && include2;
862 // Layout an input section.
864 template<int size, bool big_endian>
866 Sized_relobj<size, big_endian>::layout_section(Layout* layout,
869 typename This::Shdr& shdr,
870 unsigned int reloc_shndx,
871 unsigned int reloc_type)
874 Output_section* os = layout->layout(this, shndx, name, shdr,
875 reloc_shndx, reloc_type, &offset);
877 this->output_sections()[shndx] = os;
879 this->section_offsets_[shndx] = invalid_address;
881 this->section_offsets_[shndx] = convert_types<Address, off_t>(offset);
883 // If this section requires special handling, and if there are
884 // relocs that apply to it, then we must do the special handling
885 // before we apply the relocs.
886 if (offset == -1 && reloc_shndx != 0)
887 this->set_relocs_must_follow_section_writes();
890 // Lay out the input sections. We walk through the sections and check
891 // whether they should be included in the link. If they should, we
892 // pass them to the Layout object, which will return an output section
894 // During garbage collection (gc-sections), this function is called
895 // twice. When it is called the first time, it is for setting up some
896 // sections as roots to a work-list and to do comdat processing. Actual
897 // layout happens the second time around after all the relevant sections
898 // have been determined. The first time, is_worklist_ready is false.
899 // It is then set to true after the worklist is processed and the relevant
900 // sections are determined. Then, this function is called again to
901 // layout the sections.
903 template<int size, bool big_endian>
905 Sized_relobj<size, big_endian>::do_layout(Symbol_table* symtab,
907 Read_symbols_data* sd)
909 const unsigned int shnum = this->shnum();
910 bool is_gc_pass_one = (parameters->options().gc_sections()
911 && !symtab->gc()->is_worklist_ready());
912 bool is_gc_pass_two = (parameters->options().gc_sections()
913 && symtab->gc()->is_worklist_ready());
916 Symbols_data* gc_sd = NULL;
919 // During garbage collection save the symbols data to use it when
920 // re-entering this function.
921 gc_sd = new Symbols_data;
922 this->copy_symbols_data(gc_sd, sd, This::shdr_size * shnum);
923 this->set_symbols_data(gc_sd);
925 else if (is_gc_pass_two)
927 gc_sd = this->get_symbols_data();
930 const unsigned char* section_headers_data = NULL;
931 section_size_type section_names_size;
932 const unsigned char* symbols_data = NULL;
933 section_size_type symbols_size;
934 section_offset_type external_symbols_offset;
935 const unsigned char* symbol_names_data = NULL;
936 section_size_type symbol_names_size;
938 if (parameters->options().gc_sections())
940 section_headers_data = gc_sd->section_headers_data;
941 section_names_size = gc_sd->section_names_size;
942 symbols_data = gc_sd->symbols_data;
943 symbols_size = gc_sd->symbols_size;
944 external_symbols_offset = gc_sd->external_symbols_offset;
945 symbol_names_data = gc_sd->symbol_names_data;
946 symbol_names_size = gc_sd->symbol_names_size;
950 section_headers_data = sd->section_headers->data();
951 section_names_size = sd->section_names_size;
952 if (sd->symbols != NULL)
953 symbols_data = sd->symbols->data();
954 symbols_size = sd->symbols_size;
955 external_symbols_offset = sd->external_symbols_offset;
956 if (sd->symbol_names != NULL)
957 symbol_names_data = sd->symbol_names->data();
958 symbol_names_size = sd->symbol_names_size;
961 // Get the section headers.
962 const unsigned char* shdrs = section_headers_data;
963 const unsigned char* pshdrs;
965 // Get the section names.
966 const unsigned char* pnamesu = parameters->options().gc_sections() ?
967 gc_sd->section_names_data :
968 sd->section_names->data();
969 const char* pnames = reinterpret_cast<const char*>(pnamesu);
971 // If any input files have been claimed by plugins, we need to defer
972 // actual layout until the replacement files have arrived.
973 const bool should_defer_layout =
974 (parameters->options().has_plugins()
975 && parameters->options().plugins()->should_defer_layout());
976 unsigned int num_sections_to_defer = 0;
978 // For each section, record the index of the reloc section if any.
979 // Use 0 to mean that there is no reloc section, -1U to mean that
980 // there is more than one.
981 std::vector<unsigned int> reloc_shndx(shnum, 0);
982 std::vector<unsigned int> reloc_type(shnum, elfcpp::SHT_NULL);
983 // Skip the first, dummy, section.
984 pshdrs = shdrs + This::shdr_size;
985 for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
987 typename This::Shdr shdr(pshdrs);
989 // Count the number of sections whose layout will be deferred.
990 if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
991 ++num_sections_to_defer;
993 unsigned int sh_type = shdr.get_sh_type();
994 if (sh_type == elfcpp::SHT_REL || sh_type == elfcpp::SHT_RELA)
996 unsigned int target_shndx = this->adjust_shndx(shdr.get_sh_info());
997 if (target_shndx == 0 || target_shndx >= shnum)
999 this->error(_("relocation section %u has bad info %u"),
1004 if (reloc_shndx[target_shndx] != 0)
1005 reloc_shndx[target_shndx] = -1U;
1008 reloc_shndx[target_shndx] = i;
1009 reloc_type[target_shndx] = sh_type;
1014 Output_sections& out_sections(this->output_sections());
1015 std::vector<Address>& out_section_offsets(this->section_offsets_);
1017 if (!is_gc_pass_two)
1019 out_sections.resize(shnum);
1020 out_section_offsets.resize(shnum);
1023 // If we are only linking for symbols, then there is nothing else to
1025 if (this->input_file()->just_symbols())
1027 if (!is_gc_pass_two)
1029 delete sd->section_headers;
1030 sd->section_headers = NULL;
1031 delete sd->section_names;
1032 sd->section_names = NULL;
1037 if (num_sections_to_defer > 0)
1039 parameters->options().plugins()->add_deferred_layout_object(this);
1040 this->deferred_layout_.reserve(num_sections_to_defer);
1043 // Whether we've seen a .note.GNU-stack section.
1044 bool seen_gnu_stack = false;
1045 // The flags of a .note.GNU-stack section.
1046 uint64_t gnu_stack_flags = 0;
1048 // Keep track of which sections to omit.
1049 std::vector<bool> omit(shnum, false);
1051 // Keep track of reloc sections when emitting relocations.
1052 const bool relocatable = parameters->options().relocatable();
1053 const bool emit_relocs = (relocatable
1054 || parameters->options().emit_relocs());
1055 std::vector<unsigned int> reloc_sections;
1057 // Keep track of .eh_frame sections.
1058 std::vector<unsigned int> eh_frame_sections;
1060 // Skip the first, dummy, section.
1061 pshdrs = shdrs + This::shdr_size;
1062 for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1064 typename This::Shdr shdr(pshdrs);
1066 if (shdr.get_sh_name() >= section_names_size)
1068 this->error(_("bad section name offset for section %u: %lu"),
1069 i, static_cast<unsigned long>(shdr.get_sh_name()));
1073 const char* name = pnames + shdr.get_sh_name();
1075 if (!is_gc_pass_two)
1077 if (this->handle_gnu_warning_section(name, i, symtab))
1083 // The .note.GNU-stack section is special. It gives the
1084 // protection flags that this object file requires for the stack
1086 if (strcmp(name, ".note.GNU-stack") == 0)
1088 seen_gnu_stack = true;
1089 gnu_stack_flags |= shdr.get_sh_flags();
1093 bool discard = omit[i];
1096 if (shdr.get_sh_type() == elfcpp::SHT_GROUP)
1098 if (!this->include_section_group(symtab, layout, i, name,
1104 else if ((shdr.get_sh_flags() & elfcpp::SHF_GROUP) == 0
1105 && Layout::is_linkonce(name))
1107 if (!this->include_linkonce_section(layout, i, name, shdr))
1114 // Do not include this section in the link.
1115 out_sections[i] = NULL;
1116 out_section_offsets[i] = invalid_address;
1123 if (is_section_name_included(name)
1124 || shdr.get_sh_type() == elfcpp::SHT_INIT_ARRAY
1125 || shdr.get_sh_type() == elfcpp::SHT_FINI_ARRAY)
1127 symtab->gc()->worklist().push(Section_id(this, i));
1131 // When doing a relocatable link we are going to copy input
1132 // reloc sections into the output. We only want to copy the
1133 // ones associated with sections which are not being discarded.
1134 // However, we don't know that yet for all sections. So save
1135 // reloc sections and process them later. Garbage collection is
1136 // not triggered when relocatable code is desired.
1138 && (shdr.get_sh_type() == elfcpp::SHT_REL
1139 || shdr.get_sh_type() == elfcpp::SHT_RELA))
1141 reloc_sections.push_back(i);
1145 if (relocatable && shdr.get_sh_type() == elfcpp::SHT_GROUP)
1148 // The .eh_frame section is special. It holds exception frame
1149 // information that we need to read in order to generate the
1150 // exception frame header. We process these after all the other
1151 // sections so that the exception frame reader can reliably
1152 // determine which sections are being discarded, and discard the
1153 // corresponding information.
1155 && strcmp(name, ".eh_frame") == 0
1156 && this->check_eh_frame_flags(&shdr))
1160 out_sections[i] = reinterpret_cast<Output_section*>(1);
1161 out_section_offsets[i] = invalid_address;
1164 eh_frame_sections.push_back(i);
1170 // This is executed during the second pass of garbage
1171 // collection. do_layout has been called before and some
1172 // sections have been already discarded. Simply ignore
1173 // such sections this time around.
1174 if (out_sections[i] == NULL)
1176 gold_assert(out_section_offsets[i] == invalid_address);
1179 if ((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1180 if (symtab->gc()->referenced_list().find(Section_id(this,i))
1181 == symtab->gc()->referenced_list().end())
1183 if (parameters->options().print_gc_sections())
1184 gold_info(_("%s: removing unused section from '%s'"
1186 program_name, this->section_name(i).c_str(),
1187 this->name().c_str());
1188 out_sections[i] = NULL;
1189 out_section_offsets[i] = invalid_address;
1193 // Defer layout here if input files are claimed by plugins. When gc
1194 // is turned on this function is called twice. For the second call
1195 // should_defer_layout should be false.
1196 if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1198 gold_assert(!is_gc_pass_two);
1199 this->deferred_layout_.push_back(Deferred_layout(i, name,
1203 // Put dummy values here; real values will be supplied by
1204 // do_layout_deferred_sections.
1205 out_sections[i] = reinterpret_cast<Output_section*>(2);
1206 out_section_offsets[i] = invalid_address;
1209 // During gc_pass_two if a section that was previously deferred is
1210 // found, do not layout the section as layout_deferred_sections will
1211 // do it later from gold.cc.
1213 && (out_sections[i] == reinterpret_cast<Output_section*>(2)))
1218 // This is during garbage collection. The out_sections are
1219 // assigned in the second call to this function.
1220 out_sections[i] = reinterpret_cast<Output_section*>(1);
1221 out_section_offsets[i] = invalid_address;
1225 // When garbage collection is switched on the actual layout
1226 // only happens in the second call.
1227 this->layout_section(layout, i, name, shdr, reloc_shndx[i],
1232 if (!is_gc_pass_one)
1233 layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags);
1235 // When doing a relocatable link handle the reloc sections at the
1236 // end. Garbage collection is not turned on for relocatable code.
1238 this->size_relocatable_relocs();
1239 gold_assert(!parameters->options().gc_sections() || reloc_sections.empty());
1240 for (std::vector<unsigned int>::const_iterator p = reloc_sections.begin();
1241 p != reloc_sections.end();
1244 unsigned int i = *p;
1245 const unsigned char* pshdr;
1246 pshdr = section_headers_data + i * This::shdr_size;
1247 typename This::Shdr shdr(pshdr);
1249 unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1250 if (data_shndx >= shnum)
1252 // We already warned about this above.
1256 Output_section* data_section = out_sections[data_shndx];
1257 if (data_section == NULL)
1259 out_sections[i] = NULL;
1260 out_section_offsets[i] = invalid_address;
1264 Relocatable_relocs* rr = new Relocatable_relocs();
1265 this->set_relocatable_relocs(i, rr);
1267 Output_section* os = layout->layout_reloc(this, i, shdr, data_section,
1269 out_sections[i] = os;
1270 out_section_offsets[i] = invalid_address;
1273 // Handle the .eh_frame sections at the end.
1274 gold_assert(!is_gc_pass_one || eh_frame_sections.empty());
1275 for (std::vector<unsigned int>::const_iterator p = eh_frame_sections.begin();
1276 p != eh_frame_sections.end();
1279 gold_assert(this->has_eh_frame_);
1280 gold_assert(external_symbols_offset != 0);
1282 unsigned int i = *p;
1283 const unsigned char *pshdr;
1284 pshdr = section_headers_data + i * This::shdr_size;
1285 typename This::Shdr shdr(pshdr);
1288 Output_section* os = layout->layout_eh_frame(this,
1297 out_sections[i] = os;
1299 out_section_offsets[i] = invalid_address;
1301 out_section_offsets[i] = convert_types<Address, off_t>(offset);
1303 // If this section requires special handling, and if there are
1304 // relocs that apply to it, then we must do the special handling
1305 // before we apply the relocs.
1306 if (offset == -1 && reloc_shndx[i] != 0)
1307 this->set_relocs_must_follow_section_writes();
1312 delete[] gc_sd->section_headers_data;
1313 delete[] gc_sd->section_names_data;
1314 delete[] gc_sd->symbols_data;
1315 delete[] gc_sd->symbol_names_data;
1319 delete sd->section_headers;
1320 sd->section_headers = NULL;
1321 delete sd->section_names;
1322 sd->section_names = NULL;
1326 // Layout sections whose layout was deferred while waiting for
1327 // input files from a plugin.
1329 template<int size, bool big_endian>
1331 Sized_relobj<size, big_endian>::do_layout_deferred_sections(Layout* layout)
1333 typename std::vector<Deferred_layout>::iterator deferred;
1335 for (deferred = this->deferred_layout_.begin();
1336 deferred != this->deferred_layout_.end();
1339 typename This::Shdr shdr(deferred->shdr_data_);
1340 this->layout_section(layout, deferred->shndx_, deferred->name_.c_str(),
1341 shdr, deferred->reloc_shndx_, deferred->reloc_type_);
1344 this->deferred_layout_.clear();
1347 // Add the symbols to the symbol table.
1349 template<int size, bool big_endian>
1351 Sized_relobj<size, big_endian>::do_add_symbols(Symbol_table* symtab,
1352 Read_symbols_data* sd,
1355 if (sd->symbols == NULL)
1357 gold_assert(sd->symbol_names == NULL);
1361 const int sym_size = This::sym_size;
1362 size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1364 if (symcount * sym_size != sd->symbols_size - sd->external_symbols_offset)
1366 this->error(_("size of symbols is not multiple of symbol size"));
1370 this->symbols_.resize(symcount);
1372 const char* sym_names =
1373 reinterpret_cast<const char*>(sd->symbol_names->data());
1374 symtab->add_from_relobj(this,
1375 sd->symbols->data() + sd->external_symbols_offset,
1376 symcount, this->local_symbol_count_,
1377 sym_names, sd->symbol_names_size,
1379 &this->defined_count_);
1383 delete sd->symbol_names;
1384 sd->symbol_names = NULL;
1387 // First pass over the local symbols. Here we add their names to
1388 // *POOL and *DYNPOOL, and we store the symbol value in
1389 // THIS->LOCAL_VALUES_. This function is always called from a
1390 // singleton thread. This is followed by a call to
1391 // finalize_local_symbols.
1393 template<int size, bool big_endian>
1395 Sized_relobj<size, big_endian>::do_count_local_symbols(Stringpool* pool,
1396 Stringpool* dynpool)
1398 gold_assert(this->symtab_shndx_ != -1U);
1399 if (this->symtab_shndx_ == 0)
1401 // This object has no symbols. Weird but legal.
1405 // Read the symbol table section header.
1406 const unsigned int symtab_shndx = this->symtab_shndx_;
1407 typename This::Shdr symtabshdr(this,
1408 this->elf_file_.section_header(symtab_shndx));
1409 gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1411 // Read the local symbols.
1412 const int sym_size = This::sym_size;
1413 const unsigned int loccount = this->local_symbol_count_;
1414 gold_assert(loccount == symtabshdr.get_sh_info());
1415 off_t locsize = loccount * sym_size;
1416 const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1417 locsize, true, true);
1419 // Read the symbol names.
1420 const unsigned int strtab_shndx =
1421 this->adjust_shndx(symtabshdr.get_sh_link());
1422 section_size_type strtab_size;
1423 const unsigned char* pnamesu = this->section_contents(strtab_shndx,
1426 const char* pnames = reinterpret_cast<const char*>(pnamesu);
1428 // Loop over the local symbols.
1430 const Output_sections& out_sections(this->output_sections());
1431 unsigned int shnum = this->shnum();
1432 unsigned int count = 0;
1433 unsigned int dyncount = 0;
1434 // Skip the first, dummy, symbol.
1436 for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
1438 elfcpp::Sym<size, big_endian> sym(psyms);
1440 Symbol_value<size>& lv(this->local_values_[i]);
1443 unsigned int shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
1445 lv.set_input_shndx(shndx, is_ordinary);
1447 if (sym.get_st_type() == elfcpp::STT_SECTION)
1448 lv.set_is_section_symbol();
1449 else if (sym.get_st_type() == elfcpp::STT_TLS)
1450 lv.set_is_tls_symbol();
1452 // Save the input symbol value for use in do_finalize_local_symbols().
1453 lv.set_input_value(sym.get_st_value());
1455 // Decide whether this symbol should go into the output file.
1457 if (shndx < shnum && out_sections[shndx] == NULL)
1459 lv.set_no_output_symtab_entry();
1460 gold_assert(!lv.needs_output_dynsym_entry());
1464 if (sym.get_st_type() == elfcpp::STT_SECTION)
1466 lv.set_no_output_symtab_entry();
1467 gold_assert(!lv.needs_output_dynsym_entry());
1471 if (sym.get_st_name() >= strtab_size)
1473 this->error(_("local symbol %u section name out of range: %u >= %u"),
1474 i, sym.get_st_name(),
1475 static_cast<unsigned int>(strtab_size));
1476 lv.set_no_output_symtab_entry();
1480 // Add the symbol to the symbol table string pool.
1481 const char* name = pnames + sym.get_st_name();
1482 pool->add(name, true, NULL);
1485 // If needed, add the symbol to the dynamic symbol table string pool.
1486 if (lv.needs_output_dynsym_entry())
1488 dynpool->add(name, true, NULL);
1493 this->output_local_symbol_count_ = count;
1494 this->output_local_dynsym_count_ = dyncount;
1497 // Finalize the local symbols. Here we set the final value in
1498 // THIS->LOCAL_VALUES_ and set their output symbol table indexes.
1499 // This function is always called from a singleton thread. The actual
1500 // output of the local symbols will occur in a separate task.
1502 template<int size, bool big_endian>
1504 Sized_relobj<size, big_endian>::do_finalize_local_symbols(unsigned int index,
1507 gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
1509 const unsigned int loccount = this->local_symbol_count_;
1510 this->local_symbol_offset_ = off;
1512 const Output_sections& out_sections(this->output_sections());
1513 const std::vector<Address>& out_offsets(this->section_offsets_);
1514 unsigned int shnum = this->shnum();
1516 for (unsigned int i = 1; i < loccount; ++i)
1518 Symbol_value<size>& lv(this->local_values_[i]);
1521 unsigned int shndx = lv.input_shndx(&is_ordinary);
1523 // Set the output symbol value.
1527 if (shndx == elfcpp::SHN_ABS || shndx == elfcpp::SHN_COMMON)
1528 lv.set_output_value(lv.input_value());
1531 this->error(_("unknown section index %u for local symbol %u"),
1533 lv.set_output_value(0);
1540 this->error(_("local symbol %u section index %u out of range"),
1545 Output_section* os = out_sections[shndx];
1549 // This local symbol belongs to a section we are discarding.
1550 // In some cases when applying relocations later, we will
1551 // attempt to match it to the corresponding kept section,
1552 // so we leave the input value unchanged here.
1555 else if (out_offsets[shndx] == invalid_address)
1557 // This is a SHF_MERGE section or one which otherwise
1558 // requires special handling. We get the output address
1559 // of the start of the merged section. If this is not a
1560 // section symbol, we can then determine the final
1561 // value. If it is a section symbol, we can not, as in
1562 // that case we have to consider the addend to determine
1563 // the value to use in a relocation.
1564 if (!lv.is_section_symbol())
1565 lv.set_output_value(os->output_address(this, shndx,
1569 section_offset_type start =
1570 os->starting_output_address(this, shndx);
1571 Merged_symbol_value<size>* msv =
1572 new Merged_symbol_value<size>(lv.input_value(), start);
1573 lv.set_merged_symbol_value(msv);
1576 else if (lv.is_tls_symbol())
1577 lv.set_output_value(os->tls_offset()
1578 + out_offsets[shndx]
1579 + lv.input_value());
1581 lv.set_output_value(os->address()
1582 + out_offsets[shndx]
1583 + lv.input_value());
1586 if (lv.needs_output_symtab_entry())
1588 lv.set_output_symtab_index(index);
1595 // Set the output dynamic symbol table indexes for the local variables.
1597 template<int size, bool big_endian>
1599 Sized_relobj<size, big_endian>::do_set_local_dynsym_indexes(unsigned int index)
1601 const unsigned int loccount = this->local_symbol_count_;
1602 for (unsigned int i = 1; i < loccount; ++i)
1604 Symbol_value<size>& lv(this->local_values_[i]);
1605 if (lv.needs_output_dynsym_entry())
1607 lv.set_output_dynsym_index(index);
1614 // Set the offset where local dynamic symbol information will be stored.
1615 // Returns the count of local symbols contributed to the symbol table by
1618 template<int size, bool big_endian>
1620 Sized_relobj<size, big_endian>::do_set_local_dynsym_offset(off_t off)
1622 gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
1623 this->local_dynsym_offset_ = off;
1624 return this->output_local_dynsym_count_;
1627 // Write out the local symbols.
1629 template<int size, bool big_endian>
1631 Sized_relobj<size, big_endian>::write_local_symbols(
1633 const Stringpool* sympool,
1634 const Stringpool* dynpool,
1635 Output_symtab_xindex* symtab_xindex,
1636 Output_symtab_xindex* dynsym_xindex)
1638 const bool strip_all = parameters->options().strip_all();
1641 if (this->output_local_dynsym_count_ == 0)
1643 this->output_local_symbol_count_ = 0;
1646 gold_assert(this->symtab_shndx_ != -1U);
1647 if (this->symtab_shndx_ == 0)
1649 // This object has no symbols. Weird but legal.
1653 // Read the symbol table section header.
1654 const unsigned int symtab_shndx = this->symtab_shndx_;
1655 typename This::Shdr symtabshdr(this,
1656 this->elf_file_.section_header(symtab_shndx));
1657 gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
1658 const unsigned int loccount = this->local_symbol_count_;
1659 gold_assert(loccount == symtabshdr.get_sh_info());
1661 // Read the local symbols.
1662 const int sym_size = This::sym_size;
1663 off_t locsize = loccount * sym_size;
1664 const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
1665 locsize, true, false);
1667 // Read the symbol names.
1668 const unsigned int strtab_shndx =
1669 this->adjust_shndx(symtabshdr.get_sh_link());
1670 section_size_type strtab_size;
1671 const unsigned char* pnamesu = this->section_contents(strtab_shndx,
1674 const char* pnames = reinterpret_cast<const char*>(pnamesu);
1676 // Get views into the output file for the portions of the symbol table
1677 // and the dynamic symbol table that we will be writing.
1678 off_t output_size = this->output_local_symbol_count_ * sym_size;
1679 unsigned char* oview = NULL;
1680 if (output_size > 0)
1681 oview = of->get_output_view(this->local_symbol_offset_, output_size);
1683 off_t dyn_output_size = this->output_local_dynsym_count_ * sym_size;
1684 unsigned char* dyn_oview = NULL;
1685 if (dyn_output_size > 0)
1686 dyn_oview = of->get_output_view(this->local_dynsym_offset_,
1689 const Output_sections out_sections(this->output_sections());
1691 gold_assert(this->local_values_.size() == loccount);
1693 unsigned char* ov = oview;
1694 unsigned char* dyn_ov = dyn_oview;
1696 for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
1698 elfcpp::Sym<size, big_endian> isym(psyms);
1700 Symbol_value<size>& lv(this->local_values_[i]);
1703 unsigned int st_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
1707 gold_assert(st_shndx < out_sections.size());
1708 if (out_sections[st_shndx] == NULL)
1710 st_shndx = out_sections[st_shndx]->out_shndx();
1711 if (st_shndx >= elfcpp::SHN_LORESERVE)
1713 if (lv.needs_output_symtab_entry() && !strip_all)
1714 symtab_xindex->add(lv.output_symtab_index(), st_shndx);
1715 if (lv.needs_output_dynsym_entry())
1716 dynsym_xindex->add(lv.output_dynsym_index(), st_shndx);
1717 st_shndx = elfcpp::SHN_XINDEX;
1721 // Write the symbol to the output symbol table.
1722 if (!strip_all && lv.needs_output_symtab_entry())
1724 elfcpp::Sym_write<size, big_endian> osym(ov);
1726 gold_assert(isym.get_st_name() < strtab_size);
1727 const char* name = pnames + isym.get_st_name();
1728 osym.put_st_name(sympool->get_offset(name));
1729 osym.put_st_value(this->local_values_[i].value(this, 0));
1730 osym.put_st_size(isym.get_st_size());
1731 osym.put_st_info(isym.get_st_info());
1732 osym.put_st_other(isym.get_st_other());
1733 osym.put_st_shndx(st_shndx);
1738 // Write the symbol to the output dynamic symbol table.
1739 if (lv.needs_output_dynsym_entry())
1741 gold_assert(dyn_ov < dyn_oview + dyn_output_size);
1742 elfcpp::Sym_write<size, big_endian> osym(dyn_ov);
1744 gold_assert(isym.get_st_name() < strtab_size);
1745 const char* name = pnames + isym.get_st_name();
1746 osym.put_st_name(dynpool->get_offset(name));
1747 osym.put_st_value(this->local_values_[i].value(this, 0));
1748 osym.put_st_size(isym.get_st_size());
1749 osym.put_st_info(isym.get_st_info());
1750 osym.put_st_other(isym.get_st_other());
1751 osym.put_st_shndx(st_shndx);
1758 if (output_size > 0)
1760 gold_assert(ov - oview == output_size);
1761 of->write_output_view(this->local_symbol_offset_, output_size, oview);
1764 if (dyn_output_size > 0)
1766 gold_assert(dyn_ov - dyn_oview == dyn_output_size);
1767 of->write_output_view(this->local_dynsym_offset_, dyn_output_size,
1772 // Set *INFO to symbolic information about the offset OFFSET in the
1773 // section SHNDX. Return true if we found something, false if we
1776 template<int size, bool big_endian>
1778 Sized_relobj<size, big_endian>::get_symbol_location_info(
1781 Symbol_location_info* info)
1783 if (this->symtab_shndx_ == 0)
1786 section_size_type symbols_size;
1787 const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
1791 unsigned int symbol_names_shndx =
1792 this->adjust_shndx(this->section_link(this->symtab_shndx_));
1793 section_size_type names_size;
1794 const unsigned char* symbol_names_u =
1795 this->section_contents(symbol_names_shndx, &names_size, false);
1796 const char* symbol_names = reinterpret_cast<const char*>(symbol_names_u);
1798 const int sym_size = This::sym_size;
1799 const size_t count = symbols_size / sym_size;
1801 const unsigned char* p = symbols;
1802 for (size_t i = 0; i < count; ++i, p += sym_size)
1804 elfcpp::Sym<size, big_endian> sym(p);
1806 if (sym.get_st_type() == elfcpp::STT_FILE)
1808 if (sym.get_st_name() >= names_size)
1809 info->source_file = "(invalid)";
1811 info->source_file = symbol_names + sym.get_st_name();
1816 unsigned int st_shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
1819 && st_shndx == shndx
1820 && static_cast<off_t>(sym.get_st_value()) <= offset
1821 && (static_cast<off_t>(sym.get_st_value() + sym.get_st_size())
1824 if (sym.get_st_name() > names_size)
1825 info->enclosing_symbol_name = "(invalid)";
1828 info->enclosing_symbol_name = symbol_names + sym.get_st_name();
1829 if (parameters->options().do_demangle())
1831 char* demangled_name = cplus_demangle(
1832 info->enclosing_symbol_name.c_str(),
1833 DMGL_ANSI | DMGL_PARAMS);
1834 if (demangled_name != NULL)
1836 info->enclosing_symbol_name.assign(demangled_name);
1837 free(demangled_name);
1848 // Look for a kept section corresponding to the given discarded section,
1849 // and return its output address. This is used only for relocations in
1850 // debugging sections. If we can't find the kept section, return 0.
1852 template<int size, bool big_endian>
1853 typename Sized_relobj<size, big_endian>::Address
1854 Sized_relobj<size, big_endian>::map_to_kept_section(
1858 Kept_comdat_section *kept = this->get_kept_comdat_section(shndx);
1861 gold_assert(kept->object_ != NULL);
1863 Output_section* os = kept->object_->output_section(kept->shndx_);
1864 Address offset = kept->object_->get_output_section_offset(kept->shndx_);
1865 gold_assert(os != NULL && offset != invalid_address);
1866 return os->address() + offset;
1872 // Get symbol counts.
1874 template<int size, bool big_endian>
1876 Sized_relobj<size, big_endian>::do_get_global_symbol_counts(
1877 const Symbol_table*,
1881 *defined = this->defined_count_;
1883 for (Symbols::const_iterator p = this->symbols_.begin();
1884 p != this->symbols_.end();
1887 && (*p)->source() == Symbol::FROM_OBJECT
1888 && (*p)->object() == this
1889 && (*p)->is_defined())
1894 // Input_objects methods.
1896 // Add a regular relocatable object to the list. Return false if this
1897 // object should be ignored.
1900 Input_objects::add_object(Object* obj)
1902 // Set the global target from the first object file we recognize.
1903 Target* target = obj->target();
1904 if (!parameters->target_valid())
1905 set_parameters_target(target);
1906 else if (target != ¶meters->target())
1908 obj->error(_("incompatible target"));
1912 // Print the filename if the -t/--trace option is selected.
1913 if (parameters->options().trace())
1914 gold_info("%s", obj->name().c_str());
1916 if (!obj->is_dynamic())
1917 this->relobj_list_.push_back(static_cast<Relobj*>(obj));
1920 // See if this is a duplicate SONAME.
1921 Dynobj* dynobj = static_cast<Dynobj*>(obj);
1922 const char* soname = dynobj->soname();
1924 std::pair<Unordered_set<std::string>::iterator, bool> ins =
1925 this->sonames_.insert(soname);
1928 // We have already seen a dynamic object with this soname.
1932 this->dynobj_list_.push_back(dynobj);
1934 // If this is -lc, remember the directory in which we found it.
1935 // We use this when issuing warnings about undefined symbols: as
1936 // a heuristic, we don't warn about system libraries found in
1937 // the same directory as -lc.
1938 if (strncmp(soname, "libc.so", 7) == 0)
1940 const char* object_name = dynobj->name().c_str();
1941 const char* base = lbasename(object_name);
1942 if (base != object_name)
1943 this->system_library_directory_.assign(object_name,
1944 base - 1 - object_name);
1948 // Add this object to the cross-referencer if requested.
1949 if (parameters->options().user_set_print_symbol_counts())
1951 if (this->cref_ == NULL)
1952 this->cref_ = new Cref();
1953 this->cref_->add_object(obj);
1959 // Return whether an object was found in the system library directory.
1962 Input_objects::found_in_system_library_directory(const Object* object) const
1964 return (!this->system_library_directory_.empty()
1965 && object->name().compare(0,
1966 this->system_library_directory_.size(),
1967 this->system_library_directory_) == 0);
1970 // For each dynamic object, record whether we've seen all of its
1971 // explicit dependencies.
1974 Input_objects::check_dynamic_dependencies() const
1976 for (Dynobj_list::const_iterator p = this->dynobj_list_.begin();
1977 p != this->dynobj_list_.end();
1980 const Dynobj::Needed& needed((*p)->needed());
1981 bool found_all = true;
1982 for (Dynobj::Needed::const_iterator pneeded = needed.begin();
1983 pneeded != needed.end();
1986 if (this->sonames_.find(*pneeded) == this->sonames_.end())
1992 (*p)->set_has_unknown_needed_entries(!found_all);
1996 // Start processing an archive.
1999 Input_objects::archive_start(Archive* archive)
2001 if (parameters->options().user_set_print_symbol_counts())
2003 if (this->cref_ == NULL)
2004 this->cref_ = new Cref();
2005 this->cref_->add_archive_start(archive);
2009 // Stop processing an archive.
2012 Input_objects::archive_stop(Archive* archive)
2014 if (parameters->options().user_set_print_symbol_counts())
2015 this->cref_->add_archive_stop(archive);
2018 // Print symbol counts
2021 Input_objects::print_symbol_counts(const Symbol_table* symtab) const
2023 if (parameters->options().user_set_print_symbol_counts()
2024 && this->cref_ != NULL)
2025 this->cref_->print_symbol_counts(symtab);
2028 // Relocate_info methods.
2030 // Return a string describing the location of a relocation. This is
2031 // only used in error messages.
2033 template<int size, bool big_endian>
2035 Relocate_info<size, big_endian>::location(size_t, off_t offset) const
2037 // See if we can get line-number information from debugging sections.
2038 std::string filename;
2039 std::string file_and_lineno; // Better than filename-only, if available.
2041 Sized_dwarf_line_info<size, big_endian> line_info(this->object);
2042 // This will be "" if we failed to parse the debug info for any reason.
2043 file_and_lineno = line_info.addr2line(this->data_shndx, offset);
2045 std::string ret(this->object->name());
2047 Symbol_location_info info;
2048 if (this->object->get_symbol_location_info(this->data_shndx, offset, &info))
2050 ret += " in function ";
2051 ret += info.enclosing_symbol_name;
2053 filename = info.source_file;
2056 if (!file_and_lineno.empty())
2057 ret += file_and_lineno;
2060 if (!filename.empty())
2063 ret += this->object->section_name(this->data_shndx);
2065 // Offsets into sections have to be positive.
2066 snprintf(buf, sizeof(buf), "+0x%lx", static_cast<long>(offset));
2073 } // End namespace gold.
2078 using namespace gold;
2080 // Read an ELF file with the header and return the appropriate
2081 // instance of Object.
2083 template<int size, bool big_endian>
2085 make_elf_sized_object(const std::string& name, Input_file* input_file,
2086 off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr)
2088 int et = ehdr.get_e_type();
2089 if (et == elfcpp::ET_REL)
2091 Sized_relobj<size, big_endian>* obj =
2092 new Sized_relobj<size, big_endian>(name, input_file, offset, ehdr);
2096 else if (et == elfcpp::ET_DYN)
2098 Sized_dynobj<size, big_endian>* obj =
2099 new Sized_dynobj<size, big_endian>(name, input_file, offset, ehdr);
2105 gold_error(_("%s: unsupported ELF file type %d"),
2111 } // End anonymous namespace.
2116 // Read an ELF file and return the appropriate instance of Object.
2119 make_elf_object(const std::string& name, Input_file* input_file, off_t offset,
2120 const unsigned char* p, section_offset_type bytes)
2122 if (bytes < elfcpp::EI_NIDENT)
2124 gold_error(_("%s: ELF file too short"), name.c_str());
2128 int v = p[elfcpp::EI_VERSION];
2129 if (v != elfcpp::EV_CURRENT)
2131 if (v == elfcpp::EV_NONE)
2132 gold_error(_("%s: invalid ELF version 0"), name.c_str());
2134 gold_error(_("%s: unsupported ELF version %d"), name.c_str(), v);
2138 int c = p[elfcpp::EI_CLASS];
2139 if (c == elfcpp::ELFCLASSNONE)
2141 gold_error(_("%s: invalid ELF class 0"), name.c_str());
2144 else if (c != elfcpp::ELFCLASS32
2145 && c != elfcpp::ELFCLASS64)
2147 gold_error(_("%s: unsupported ELF class %d"), name.c_str(), c);
2151 int d = p[elfcpp::EI_DATA];
2152 if (d == elfcpp::ELFDATANONE)
2154 gold_error(_("%s: invalid ELF data encoding"), name.c_str());
2157 else if (d != elfcpp::ELFDATA2LSB
2158 && d != elfcpp::ELFDATA2MSB)
2160 gold_error(_("%s: unsupported ELF data encoding %d"), name.c_str(), d);
2164 bool big_endian = d == elfcpp::ELFDATA2MSB;
2166 if (c == elfcpp::ELFCLASS32)
2168 if (bytes < elfcpp::Elf_sizes<32>::ehdr_size)
2170 gold_error(_("%s: ELF file too short"), name.c_str());
2175 #ifdef HAVE_TARGET_32_BIG
2176 elfcpp::Ehdr<32, true> ehdr(p);
2177 return make_elf_sized_object<32, true>(name, input_file,
2180 gold_error(_("%s: not configured to support "
2181 "32-bit big-endian object"),
2188 #ifdef HAVE_TARGET_32_LITTLE
2189 elfcpp::Ehdr<32, false> ehdr(p);
2190 return make_elf_sized_object<32, false>(name, input_file,
2193 gold_error(_("%s: not configured to support "
2194 "32-bit little-endian object"),
2202 if (bytes < elfcpp::Elf_sizes<64>::ehdr_size)
2204 gold_error(_("%s: ELF file too short"), name.c_str());
2209 #ifdef HAVE_TARGET_64_BIG
2210 elfcpp::Ehdr<64, true> ehdr(p);
2211 return make_elf_sized_object<64, true>(name, input_file,
2214 gold_error(_("%s: not configured to support "
2215 "64-bit big-endian object"),
2222 #ifdef HAVE_TARGET_64_LITTLE
2223 elfcpp::Ehdr<64, false> ehdr(p);
2224 return make_elf_sized_object<64, false>(name, input_file,
2227 gold_error(_("%s: not configured to support "
2228 "64-bit little-endian object"),
2236 // Instantiate the templates we need.
2238 #ifdef HAVE_TARGET_32_LITTLE
2241 Object::read_section_data<32, false>(elfcpp::Elf_file<32, false, Object>*,
2242 Read_symbols_data*);
2245 #ifdef HAVE_TARGET_32_BIG
2248 Object::read_section_data<32, true>(elfcpp::Elf_file<32, true, Object>*,
2249 Read_symbols_data*);
2252 #ifdef HAVE_TARGET_64_LITTLE
2255 Object::read_section_data<64, false>(elfcpp::Elf_file<64, false, Object>*,
2256 Read_symbols_data*);
2259 #ifdef HAVE_TARGET_64_BIG
2262 Object::read_section_data<64, true>(elfcpp::Elf_file<64, true, Object>*,
2263 Read_symbols_data*);
2266 #ifdef HAVE_TARGET_32_LITTLE
2268 class Sized_relobj<32, false>;
2271 #ifdef HAVE_TARGET_32_BIG
2273 class Sized_relobj<32, true>;
2276 #ifdef HAVE_TARGET_64_LITTLE
2278 class Sized_relobj<64, false>;
2281 #ifdef HAVE_TARGET_64_BIG
2283 class Sized_relobj<64, true>;
2286 #ifdef HAVE_TARGET_32_LITTLE
2288 struct Relocate_info<32, false>;
2291 #ifdef HAVE_TARGET_32_BIG
2293 struct Relocate_info<32, true>;
2296 #ifdef HAVE_TARGET_64_LITTLE
2298 struct Relocate_info<64, false>;
2301 #ifdef HAVE_TARGET_64_BIG
2303 struct Relocate_info<64, true>;
2306 } // End namespace gold.