1 // object.cc -- support for an object file for linking in gold
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
4 // Free Software Foundation, Inc.
5 // Written by Ian Lance Taylor <iant@google.com>.
7 // This file is part of gold.
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.
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.
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.
30 #include "libiberty.h"
33 #include "target-select.h"
34 #include "dwarf_reader.h"
43 #include "compressed_output.h"
44 #include "incremental.h"
49 // Struct Read_symbols_data.
51 // Destroy any remaining File_view objects and buffers of decompressed
54 Read_symbols_data::~Read_symbols_data()
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)
62 if (this->symbol_names != NULL)
63 delete this->symbol_names;
64 if (this->versym != NULL)
66 if (this->verdef != NULL)
68 if (this->verneed != NULL)
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.
78 template<int size, bool big_endian>
80 Xindex::initialize_symtab_xindex(Object* object, unsigned int symtab_shndx)
82 if (!this->symtab_xindex_.empty())
85 gold_assert(symtab_shndx != 0);
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();
93 if (object->section_type(i) == elfcpp::SHT_SYMTAB_SHNDX
94 && this->adjust_shndx(object->section_link(i)) == symtab_shndx)
96 this->read_symtab_xindex<size, big_endian>(object, i, NULL);
101 object->error(_("missing SHT_SYMTAB_SHNDX section"));
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
108 template<int size, bool big_endian>
110 Xindex::read_symtab_xindex(Object* object, unsigned int xindex_shndx,
111 const unsigned char* pshdrs)
113 section_size_type bytecount;
114 const unsigned char* contents;
116 contents = object->section_contents(xindex_shndx, &bytecount, false);
119 const unsigned char* p = (pshdrs
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);
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)
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));
137 // Symbol symndx has a section of SHN_XINDEX; return the real section
141 Xindex::sym_xindex_to_shndx(Object* object, unsigned int symndx)
143 if (symndx >= this->symtab_xindex_.size())
145 object->error(_("symbol %u out of range for SHT_SYMTAB_SHNDX section"),
147 return elfcpp::SHN_UNDEF;
149 unsigned int shndx = this->symtab_xindex_[symndx];
150 if (shndx < elfcpp::SHN_LORESERVE || shndx >= object->shnum())
152 object->error(_("extended index for symbol %u out of range: %u"),
154 return elfcpp::SHN_UNDEF;
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
166 Object::error(const char* format, ...) const
169 va_start(args, format);
171 if (vasprintf(&buf, format, args) < 0)
174 gold_error(_("%s: %s"), this->name().c_str(), buf);
178 // Return a view of the contents of a section.
181 Object::section_contents(unsigned int shndx, section_size_type* plen,
183 { return this->do_section_contents(shndx, plen, cache); }
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.
188 template<int size, bool big_endian>
190 Object::read_section_data(elfcpp::Elf_file<size, big_endian, Object>* elf_file,
191 Read_symbols_data* sd)
193 const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
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,
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);
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()));
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,
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.
222 Object::handle_gnu_warning_section(const char* name, unsigned int shndx,
223 Symbol_table* symtab)
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)
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
235 section_size_type len;
236 const unsigned char* contents = this->section_contents(shndx, &len,
240 const char* warning = name + warn_prefix_len;
241 contents = reinterpret_cast<const unsigned char*>(warning);
242 len = strlen(warning);
244 std::string warning(reinterpret_cast<const char*>(contents), len);
245 symtab->add_warning(name + warn_prefix_len, this, warning);
251 // If NAME is the name of the special section which indicates that
252 // this object was compiled with -fsplit-stack, mark it accordingly.
255 Object::handle_split_stack_section(const char* name)
257 if (strcmp(name, ".note.GNU-split-stack") == 0)
259 this->uses_split_stack_ = true;
262 if (strcmp(name, ".note.GNU-no-split-stack") == 0)
264 this->has_no_split_stack_ = true;
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
277 Relobj::copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd,
278 unsigned int section_header_size)
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)
291 gc_sd->symbols_data =
292 new unsigned char[sd->symbols_size];
293 memcpy(gc_sd->symbols_data, sd->symbols->data(),
298 gc_sd->symbols_data = NULL;
300 gc_sd->symbols_size = sd->symbols_size;
301 gc_sd->external_symbols_offset = sd->external_symbols_offset;
302 if (sd->symbol_names != NULL)
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);
311 gc_sd->symbol_names_data = NULL;
313 gc_sd->symbol_names_size = sd->symbol_names_size;
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.
321 Relobj::is_section_name_included(const char* name)
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")))
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.
351 Relobj::finalize_incremental_relocs(Layout* layout, bool clear_counts)
353 unsigned int nsyms = this->get_global_symbols()->size();
354 this->reloc_bases_ = new unsigned int[nsyms];
356 gold_assert(this->reloc_bases_ != NULL);
357 gold_assert(layout->incremental_inputs() != NULL);
359 unsigned int rindex = layout->incremental_inputs()->get_reloc_count();
360 for (unsigned int i = 0; i < nsyms; ++i)
362 this->reloc_bases_[i] = rindex;
363 rindex += this->reloc_counts_[i];
365 this->reloc_counts_[i] = 0;
367 layout->incremental_inputs()->set_reloc_count(rindex);
370 // Class Sized_relobj.
372 // Iterate over local symbols, calling a visitor class V for each GOT offset
373 // associated with a local symbol.
375 template<int size, bool big_endian>
377 Sized_relobj<size, big_endian>::do_for_all_local_got_entries(
378 Got_offset_list::Visitor* v) const
380 unsigned int nsyms = this->local_symbol_count();
381 for (unsigned int i = 0; i < nsyms; i++)
383 Local_got_offsets::const_iterator p = this->local_got_offsets_.find(i);
384 if (p != this->local_got_offsets_.end())
386 const Got_offset_list* got_offsets = p->second;
387 got_offsets->for_all_got_offsets(v);
392 // Get the address of an output section.
394 template<int size, bool big_endian>
396 Sized_relobj<size, big_endian>::do_output_section_address(
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);
404 const Output_section* os = this->do_output_section(shndx);
405 gold_assert(os != NULL);
406 return os->address();
409 // Class Sized_relobj_file.
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,
416 const elfcpp::Ehdr<size, big_endian>& ehdr)
417 : Sized_relobj<size, big_endian>(name, input_file, offset),
418 elf_file_(this, ehdr),
420 local_symbol_count_(0),
421 output_local_symbol_count_(0),
422 output_local_dynsym_count_(0),
425 local_symbol_offset_(0),
426 local_dynsym_offset_(0),
428 local_plt_offsets_(),
429 kept_comdat_sections_(),
430 has_eh_frame_(false),
431 discarded_eh_frame_shndx_(-1U),
433 deferred_layout_relocs_(),
434 compressed_sections_()
436 this->e_type_ = ehdr.get_e_type();
439 template<int size, bool big_endian>
440 Sized_relobj_file<size, big_endian>::~Sized_relobj_file()
444 // Set up an object file based on the file header. This sets up the
445 // section information.
447 template<int size, bool big_endian>
449 Sized_relobj_file<size, big_endian>::do_setup()
451 const unsigned int shnum = this->elf_file_.shnum();
452 this->set_shnum(shnum);
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.
460 template<int size, bool big_endian>
462 Sized_relobj_file<size, big_endian>::find_symtab(const unsigned char* pshdrs)
464 const unsigned int shnum = this->shnum();
465 this->symtab_shndx_ = 0;
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;
477 p -= This::shdr_size;
478 typename This::Shdr shdr(p);
479 if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB)
481 this->symtab_shndx_ = i;
482 if (xindex_shndx > 0 && xindex_link == i)
485 new Xindex(this->elf_file_.large_shndx_offset());
486 xindex->read_symtab_xindex<size, big_endian>(this,
489 this->set_xindex(xindex);
494 // Try to pick up the SHT_SYMTAB_SHNDX section, if there is
495 // one. This will work if it follows the SHT_SYMTAB
497 if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX)
500 xindex_link = this->adjust_shndx(shdr.get_sh_link());
506 // Return the Xindex structure to use for object with lots of
509 template<int size, bool big_endian>
511 Sized_relobj_file<size, big_endian>::do_initialize_xindex()
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_);
519 // Return whether SHDR has the right type and flags to be a GNU
520 // .eh_frame section.
522 template<int size, bool big_endian>
524 Sized_relobj_file<size, big_endian>::check_eh_frame_flags(
525 const elfcpp::Shdr<size, big_endian>* shdr) const
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);
533 // Find the section header with the given name.
535 template<int size, bool big_endian>
538 const unsigned char* pshdrs,
541 section_size_type names_size,
542 const unsigned char* hdr) const
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;
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();
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
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),
579 while (hdr < hdr_end)
581 typename elfcpp::Shdr<size, big_endian> shdr(hdr);
582 if (shdr.get_sh_name() == sh_name)
592 // Return whether there is a GNU .eh_frame section, given the section
593 // headers and the section names.
595 template<int size, bool big_endian>
597 Sized_relobj_file<size, big_endian>::find_eh_frame(
598 const unsigned char* pshdrs,
600 section_size_type names_size) const
602 const unsigned char* s = NULL;
606 s = this->template find_shdr<size, big_endian>(pshdrs, ".eh_frame",
607 names, names_size, s);
611 typename This::Shdr shdr(s);
612 if (this->check_eh_frame_flags(&shdr))
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".
623 need_decompressed_section(const char* name)
625 // Skip over the ".zdebug" and a quick check for the "_".
630 #ifdef ENABLE_THREADS
631 // Decompressing these sections now will help only if we're
633 if (parameters->options().threads())
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)
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))
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)
666 // Build a table for any compressed debug sections, mapping each section index
667 // to the uncompressed size and (if needed) the decompressed contents.
669 template<int size, bool big_endian>
670 Compressed_section_map*
671 build_compressed_section_map(
672 const unsigned char* pshdrs,
675 section_size_type names_size,
676 Sized_relobj_file<size, big_endian>* obj)
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;
682 for (unsigned int i = 1; i < shnum; ++i, p += shdr_size)
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)
688 if (shdr.get_sh_name() >= names_size)
690 obj->error(_("bad section name offset for section %u: %lu"),
691 i, static_cast<unsigned long>(shdr.get_sh_name()));
695 const char* name = names + shdr.get_sh_name();
696 if (is_compressed_debug_section(name))
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)
707 unsigned char* uncompressed_data = NULL;
708 if (need_decompressed_section(name))
710 uncompressed_data = new unsigned char[uncompressed_size];
711 if (decompress_input_section(contents, len,
714 info.contents = uncompressed_data;
716 delete[] uncompressed_data;
718 (*uncompressed_map)[i] = info;
723 return uncompressed_map;
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.
729 template<int size, bool big_endian>
731 Sized_relobj_file<size, big_endian>::do_find_special_sections(
732 Read_symbols_data* sd)
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);
738 if (this->find_eh_frame(pshdrs, names, sd->section_names_size))
739 this->has_eh_frame_ = true;
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",
753 // Read the sections and symbols from an object file.
755 template<int size, bool big_endian>
757 Sized_relobj_file<size, big_endian>::do_read_symbols(Read_symbols_data* sd)
759 this->read_section_data(&this->elf_file_, sd);
761 const unsigned char* const pshdrs = sd->section_headers->data();
763 this->find_symtab(pshdrs);
765 bool need_local_symbols = this->do_find_special_sections(sd);
768 sd->symbols_size = 0;
769 sd->external_symbols_offset = 0;
770 sd->symbol_names = NULL;
771 sd->symbol_names_size = 0;
773 if (this->symtab_shndx_ == 0)
775 // No symbol table. Weird but legal.
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);
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
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;
803 off_t readoff = need_local_symbols ? dataoff : extoff;
804 section_size_type readsize = need_local_symbols ? datasize : extsize;
808 // No external symbols. Also weird but also legal.
812 File_view* fvsymtab = this->get_lasting_view(readoff, readsize, true, false);
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())
818 this->error(_("invalid symbol table name index: %u"), strtab_shndx);
821 typename This::Shdr strtabshdr(pshdrs + strtab_shndx * This::shdr_size);
822 if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB)
824 this->error(_("symbol table name section has wrong type: %u"),
825 static_cast<unsigned int>(strtabshdr.get_sh_type()));
829 // Read the symbol names.
830 File_view* fvstrtab = this->get_lasting_view(strtabshdr.get_sh_offset(),
831 strtabshdr.get_sh_size(),
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());
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.
849 template<int size, bool big_endian>
851 Sized_relobj_file<size, big_endian>::symbol_section_and_value(unsigned int sym,
855 section_size_type symbols_size;
856 const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
860 const size_t count = symbols_size / This::sym_size;
861 gold_assert(sym < count);
863 elfcpp::Sym<size, big_endian> elfsym(symbols + sym * This::sym_size);
864 *value = elfsym.get_st_value();
866 return this->adjust_sym_shndx(sym, elfsym.get_st_shndx(), is_ordinary);
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.
875 template<int size, bool big_endian>
877 Sized_relobj_file<size, big_endian>::include_section_group(
878 Symbol_table* symtab,
882 const unsigned char* shdrs,
883 const char* section_names,
884 section_size_type section_names_size,
885 std::vector<bool>* omit)
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);
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);
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.
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));
910 // Read the symbol table entry.
911 unsigned int symndx = shdr.get_sh_info();
912 if (symndx >= symshdr.get_sh_size() / This::sym_size)
914 this->error(_("section group %u info %u out of range"),
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,
921 elfcpp::Sym<size, big_endian> sym(psym);
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()),
928 const char* psymnames = reinterpret_cast<const char*>(psymnamesu);
930 // Get the section group signature.
931 if (sym.get_st_name() >= symnamelen)
933 this->error(_("symbol %u name offset %u out of range"),
934 symndx, sym.get_st_name());
938 std::string signature(psymnames + sym.get_st_name());
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)
946 unsigned int sym_shndx = this->adjust_sym_shndx(symndx,
949 if (!is_ordinary || sym_shndx >= this->shnum())
951 this->error(_("symbol %u invalid section index %u"),
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();
960 // Record this section group in the layout, and see whether we've already
961 // seen one with the same signature.
964 Kept_section* kept_section = NULL;
966 if ((flags & elfcpp::GRP_COMDAT) == 0)
968 include_group = true;
973 include_group = layout->find_or_add_kept_section(signature,
975 true, &kept_section);
979 if (is_comdat && include_group)
981 Incremental_inputs* incremental_inputs = layout->incremental_inputs();
982 if (incremental_inputs != NULL)
983 incremental_inputs->report_comdat_group(this, signature.c_str());
986 size_t count = shdr.get_sh_size() / sizeof(elfcpp::Elf_Word);
988 std::vector<unsigned int> shndxes;
989 bool relocate_group = include_group && parameters->options().relocatable();
991 shndxes.reserve(count - 1);
993 for (size_t i = 1; i < count; ++i)
995 elfcpp::Elf_Word shndx =
996 this->adjust_shndx(elfcpp::Swap<32, big_endian>::readval(pword + i));
999 shndxes.push_back(shndx);
1001 if (shndx >= this->shnum())
1003 this->error(_("section %u in section group %u out of range"),
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.
1011 this->error(_("invalid section group %u refers to earlier section %u"),
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)
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
1023 std::string mname(section_names + member_shdr.get_sh_name());
1028 kept_section->add_comdat_section(mname, shndx,
1029 member_shdr.get_sh_size());
1033 (*omit)[shndx] = true;
1037 Relobj* kept_object = kept_section->object();
1038 if (kept_section->is_comdat())
1040 // Find the corresponding kept section, and store
1041 // that info in the discarded section table.
1042 unsigned int kept_shndx;
1044 if (kept_section->find_comdat_section(mname, &kept_shndx,
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,
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.
1065 && (kept_section->linkonce_size()
1066 == member_shdr.get_sh_size()))
1067 this->set_kept_comdat_section(shndx, kept_object,
1068 kept_section->shndx());
1075 layout->layout_group(symtab, this, index, name, signature.c_str(),
1076 shdr, flags, &shndxes);
1078 return include_group;
1081 // Whether to include a linkonce section in the link. NAME is the
1082 // name of the section and SHDR is the section header.
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
1096 template<int size, bool big_endian>
1098 Sized_relobj_file<size, big_endian>::include_linkonce_section(
1102 const elfcpp::Shdr<size, big_endian>& shdr)
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);
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,
1125 bool include2 = layout->find_or_add_kept_section(sig2, this, index, false,
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
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());
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;
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);
1159 kept1->set_linkonce_size(sh_size);
1160 kept2->set_linkonce_size(sh_size);
1163 return include1 && include2;
1166 // Layout an input section.
1168 template<int size, bool big_endian>
1170 Sized_relobj_file<size, big_endian>::layout_section(
1174 const typename This::Shdr& shdr,
1175 unsigned int reloc_shndx,
1176 unsigned int reloc_type)
1179 Output_section* os = layout->layout(this, shndx, name, shdr,
1180 reloc_shndx, reloc_type, &offset);
1182 this->output_sections()[shndx] = os;
1184 this->section_offsets()[shndx] = invalid_address;
1186 this->section_offsets()[shndx] = convert_types<Address, off_t>(offset);
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();
1195 // Layout an input .eh_frame section.
1197 template<int size, bool big_endian>
1199 Sized_relobj_file<size, big_endian>::layout_eh_frame_section(
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,
1206 const typename This::Shdr& shdr,
1207 unsigned int reloc_shndx,
1208 unsigned int reloc_type)
1210 gold_assert(this->has_eh_frame_);
1213 Output_section* os = layout->layout_eh_frame(this,
1223 this->output_sections()[shndx] = os;
1224 if (os == NULL || offset == -1)
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;
1233 this->section_offsets()[shndx] = convert_types<Address, off_t>(offset);
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();
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
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.
1260 template<int size, bool big_endian>
1262 Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
1264 Read_symbols_data* sd)
1266 const unsigned int shnum = this->shnum();
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());
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;
1278 Symbols_data* gc_sd = NULL;
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. */
1285 gc_sd = this->get_symbols_data();
1288 gold_assert(sd != NULL);
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());
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);
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;
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;
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;
1341 // Get the section headers.
1342 const unsigned char* shdrs = section_headers_data;
1343 const unsigned char* pshdrs;
1345 // Get the section names.
1346 const unsigned char* pnamesu = (is_two_pass
1347 ? gc_sd->section_names_data
1348 : sd->section_names->data());
1350 const char* pnames = reinterpret_cast<const char*>(pnamesu);
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;
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)
1368 typename This::Shdr shdr(pshdrs);
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;
1374 unsigned int sh_type = shdr.get_sh_type();
1375 if (sh_type == elfcpp::SHT_REL || sh_type == elfcpp::SHT_RELA)
1377 unsigned int target_shndx = this->adjust_shndx(shdr.get_sh_info());
1378 if (target_shndx == 0 || target_shndx >= shnum)
1380 this->error(_("relocation section %u has bad info %u"),
1385 if (reloc_shndx[target_shndx] != 0)
1386 reloc_shndx[target_shndx] = -1U;
1389 reloc_shndx[target_shndx] = i;
1390 reloc_type[target_shndx] = sh_type;
1395 Output_sections& out_sections(this->output_sections());
1396 std::vector<Address>& out_section_offsets(this->section_offsets());
1400 out_sections.resize(shnum);
1401 out_section_offsets.resize(shnum);
1404 // If we are only linking for symbols, then there is nothing else to
1406 if (this->input_file()->just_symbols())
1410 delete sd->section_headers;
1411 sd->section_headers = NULL;
1412 delete sd->section_names;
1413 sd->section_names = NULL;
1418 if (num_sections_to_defer > 0)
1420 parameters->options().plugins()->add_deferred_layout_object(this);
1421 this->deferred_layout_.reserve(num_sections_to_defer);
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;
1429 // Keep track of which sections to omit.
1430 std::vector<bool> omit(shnum, false);
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;
1438 // Keep track of .eh_frame sections.
1439 std::vector<unsigned int> eh_frame_sections;
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;
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)
1449 typename This::Shdr shdr(pshdrs);
1451 if (shdr.get_sh_name() >= section_names_size)
1453 this->error(_("bad section name offset for section %u: %lu"),
1454 i, static_cast<unsigned long>(shdr.get_sh_name()));
1458 const char* name = pnames + shdr.get_sh_name();
1462 if (this->handle_gnu_warning_section(name, i, symtab))
1464 if (!relocatable && !parameters->options().shared())
1468 // The .note.GNU-stack section is special. It gives the
1469 // protection flags that this object file requires for the stack
1471 if (strcmp(name, ".note.GNU-stack") == 0)
1473 seen_gnu_stack = true;
1474 gnu_stack_flags |= shdr.get_sh_flags();
1478 // The .note.GNU-split-stack section is also special. It
1479 // indicates that the object was compiled with
1481 if (this->handle_split_stack_section(name))
1483 if (!relocatable && !parameters->options().shared())
1487 // Skip attributes section.
1488 if (parameters->target().is_attributes_section(name))
1493 bool discard = omit[i];
1496 if (shdr.get_sh_type() == elfcpp::SHT_GROUP)
1498 if (!this->include_section_group(symtab, layout, i, name,
1504 else if ((shdr.get_sh_flags() & elfcpp::SHF_GROUP) == 0
1505 && Layout::is_linkonce(name))
1507 if (!this->include_linkonce_section(layout, i, name, shdr))
1512 // Add the section to the incremental inputs layout.
1513 Incremental_inputs* incremental_inputs = layout->incremental_inputs();
1514 if (incremental_inputs != NULL
1516 && can_incremental_update(shdr.get_sh_type()))
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);
1527 // Do not include this section in the link.
1528 out_sections[i] = NULL;
1529 out_section_offsets[i] = invalid_address;
1534 if (is_pass_one && parameters->options().gc_sections())
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)
1541 symtab->gc()->worklist().push(Section_id(this, i));
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))
1549 symtab->gc()->add_cident_section(name, Section_id(this, i));
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.
1560 && (shdr.get_sh_type() == elfcpp::SHT_REL
1561 || shdr.get_sh_type() == elfcpp::SHT_RELA))
1563 reloc_sections.push_back(i);
1567 if (relocatable && shdr.get_sh_type() == elfcpp::SHT_GROUP)
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.
1577 && strcmp(name, ".eh_frame") == 0
1578 && this->check_eh_frame_flags(&shdr))
1582 out_sections[i] = reinterpret_cast<Output_section*>(1);
1583 out_section_offsets[i] = invalid_address;
1585 else if (should_defer_layout)
1586 this->deferred_layout_.push_back(Deferred_layout(i, name,
1591 eh_frame_sections.push_back(i);
1595 if (is_pass_two && parameters->options().gc_sections())
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)
1603 gold_assert(out_section_offsets[i] == invalid_address);
1606 if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1607 && symtab->gc()->is_section_garbage(this, i))
1609 if (parameters->options().print_gc_sections())
1610 gold_info(_("%s: removing unused section from '%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;
1620 if (is_pass_two && parameters->options().icf_enabled())
1622 if (out_sections[i] == NULL)
1624 gold_assert(out_section_offsets[i] == invalid_address);
1627 if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1628 && symtab->icf()->is_section_folded(this, i))
1630 if (parameters->options().print_icf_sections())
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());
1643 out_sections[i] = NULL;
1644 out_section_offsets[i] = invalid_address;
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))
1654 gold_assert(!is_pass_two);
1655 this->deferred_layout_.push_back(Deferred_layout(i, name,
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;
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.
1670 && (out_sections[i] == reinterpret_cast<Output_section*>(2)))
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;
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],
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.
1691 && parameters->options().gdb_index()
1692 && !(shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
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);
1705 layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags, this);
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.
1711 this->size_relocatable_relocs();
1713 gold_assert(!is_two_pass || reloc_sections.empty());
1715 for (std::vector<unsigned int>::const_iterator p = reloc_sections.begin();
1716 p != reloc_sections.end();
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);
1724 unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1725 if (data_shndx >= shnum)
1727 // We already warned about this above.
1731 Output_section* data_section = out_sections[data_shndx];
1732 if (data_section == reinterpret_cast<Output_section*>(2))
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;
1743 if (data_section == NULL)
1745 out_sections[i] = NULL;
1746 out_section_offsets[i] = invalid_address;
1750 Relocatable_relocs* rr = new Relocatable_relocs();
1751 this->set_relocatable_relocs(i, rr);
1753 Output_section* os = layout->layout_reloc(this, i, shdr, data_section,
1755 out_sections[i] = os;
1756 out_section_offsets[i] = invalid_address;
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();
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);
1770 this->layout_eh_frame_section(layout,
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();
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]);
1794 for (std::vector<unsigned int>::const_iterator p
1795 = debug_types_sections.begin();
1796 p != debug_types_sections.end();
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]);
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);
1814 delete sd->section_headers;
1815 sd->section_headers = NULL;
1816 delete sd->section_names;
1817 sd->section_names = NULL;
1821 // Layout sections whose layout was deferred while waiting for
1822 // input files from a plugin.
1824 template<int size, bool big_endian>
1826 Sized_relobj_file<size, big_endian>::do_layout_deferred_sections(Layout* layout)
1828 typename std::vector<Deferred_layout>::iterator deferred;
1830 for (deferred = this->deferred_layout_.begin();
1831 deferred != this->deferred_layout_.end();
1834 typename This::Shdr shdr(deferred->shdr_data_);
1836 if (!parameters->options().relocatable()
1837 && deferred->name_ == ".eh_frame"
1838 && this->check_eh_frame_flags(&shdr))
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.
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,
1856 sd.symbol_names->data(),
1857 sd.symbol_names_size,
1860 deferred->reloc_shndx_,
1861 deferred->reloc_type_);
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_))
1870 this->layout_section(layout, deferred->shndx_, deferred->name_.c_str(),
1871 shdr, deferred->reloc_shndx_,
1872 deferred->reloc_type_);
1875 this->deferred_layout_.clear();
1877 // Now handle the deferred relocation sections.
1879 Output_sections& out_sections(this->output_sections());
1880 std::vector<Address>& out_section_offsets(this->section_offsets());
1882 for (deferred = this->deferred_layout_relocs_.begin();
1883 deferred != this->deferred_layout_relocs_.end();
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());
1890 Output_section* data_section = out_sections[data_shndx];
1891 if (data_section == NULL)
1893 out_sections[shndx] = NULL;
1894 out_section_offsets[shndx] = invalid_address;
1898 Relocatable_relocs* rr = new Relocatable_relocs();
1899 this->set_relocatable_relocs(shndx, rr);
1901 Output_section* os = layout->layout_reloc(this, shndx, shdr,
1903 out_sections[shndx] = os;
1904 out_section_offsets[shndx] = invalid_address;
1908 // Add the symbols to the symbol table.
1910 template<int size, bool big_endian>
1912 Sized_relobj_file<size, big_endian>::do_add_symbols(Symbol_table* symtab,
1913 Read_symbols_data* sd,
1916 if (sd->symbols == NULL)
1918 gold_assert(sd->symbol_names == NULL);
1922 const int sym_size = This::sym_size;
1923 size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1925 if (symcount * sym_size != sd->symbols_size - sd->external_symbols_offset)
1927 this->error(_("size of symbols is not multiple of symbol size"));
1931 this->symbols_.resize(symcount);
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,
1940 &this->defined_count_);
1944 delete sd->symbol_names;
1945 sd->symbol_names = NULL;
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
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,
1958 Read_symbols_data* sd,
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)
1971 const unsigned char* p = syms;
1973 for (size_t i = 0; i < symcount; ++i, p += sym_size)
1975 elfcpp::Sym<size, big_endian> sym(p);
1976 unsigned int st_shndx = sym.get_st_shndx();
1977 if (st_shndx == elfcpp::SHN_UNDEF)
1980 unsigned int st_name = sym.get_st_name();
1981 const char* name = sym_names + st_name;
1983 Archive::Should_include t = Archive::should_include_member(symtab,
1989 if (t == Archive::SHOULD_INCLUDE_YES)
1998 return Archive::SHOULD_INCLUDE_UNKNOWN;
2001 // Iterate over global defined symbols, calling a visitor class V for each.
2003 template<int size, bool big_endian>
2005 Sized_relobj_file<size, big_endian>::do_for_all_global_symbols(
2006 Read_symbols_data* sd,
2007 Library_base::Symbol_visitor_base* v)
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)
2016 const unsigned char* p = syms;
2018 for (size_t i = 0; i < symcount; ++i, p += sym_size)
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());
2026 // Return whether the local symbol SYMNDX has a PLT offset.
2028 template<int size, bool big_endian>
2030 Sized_relobj_file<size, big_endian>::local_has_plt_offset(
2031 unsigned int symndx) const
2033 typename Local_plt_offsets::const_iterator p =
2034 this->local_plt_offsets_.find(symndx);
2035 return p != this->local_plt_offsets_.end();
2038 // Get the PLT offset of a local symbol.
2040 template<int size, bool big_endian>
2042 Sized_relobj_file<size, big_endian>::do_local_plt_offset(
2043 unsigned int symndx) const
2045 typename Local_plt_offsets::const_iterator p =
2046 this->local_plt_offsets_.find(symndx);
2047 gold_assert(p != this->local_plt_offsets_.end());
2051 // Set the PLT offset of a local symbol.
2053 template<int size, bool big_endian>
2055 Sized_relobj_file<size, big_endian>::set_local_plt_offset(
2056 unsigned int symndx, unsigned int plt_offset)
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);
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.
2069 template<int size, bool big_endian>
2071 Sized_relobj_file<size, big_endian>::do_count_local_symbols(Stringpool* pool,
2072 Stringpool* dynpool)
2074 gold_assert(this->symtab_shndx_ != -1U);
2075 if (this->symtab_shndx_ == 0)
2077 // This object has no symbols. Weird but legal.
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);
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);
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,
2102 const char* pnames = reinterpret_cast<const char*>(pnamesu);
2104 // Loop over the local symbols.
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.
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)
2117 elfcpp::Sym<size, big_endian> sym(psyms);
2119 Symbol_value<size>& lv(this->local_values_[i]);
2122 unsigned int shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
2124 lv.set_input_shndx(shndx, is_ordinary);
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();
2133 // Save the input symbol value for use in do_finalize_local_symbols().
2134 lv.set_input_value(sym.get_st_value());
2136 // Decide whether this symbol should go into the output file.
2138 if ((shndx < shnum && out_sections[shndx] == NULL)
2139 || shndx == this->discarded_eh_frame_shndx_)
2141 lv.set_no_output_symtab_entry();
2142 gold_assert(!lv.needs_output_dynsym_entry());
2146 if (sym.get_st_type() == elfcpp::STT_SECTION
2147 || !this->adjust_local_symbol(&lv))
2149 lv.set_no_output_symtab_entry();
2150 gold_assert(!lv.needs_output_dynsym_entry());
2154 if (sym.get_st_name() >= strtab_size)
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();
2163 const char* name = pnames + sym.get_st_name();
2165 // If needed, add the symbol to the dynamic symbol table string pool.
2166 if (lv.needs_output_dynsym_entry())
2168 dynpool->add(name, true, NULL);
2173 || (discard_all && lv.may_be_discarded_from_output_symtab()))
2175 lv.set_no_output_symtab_entry();
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
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.
2190 // We do not discard a symbol if it needs a dynamic symbol entry.
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))
2197 lv.set_no_output_symtab_entry();
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))
2205 lv.set_no_output_symtab_entry();
2209 // Add the symbol to the symbol table string pool.
2210 pool->add(name, true, NULL);
2214 this->output_local_symbol_count_ = count;
2215 this->output_local_dynsym_count_ = dyncount;
2218 // Compute the final value of a local symbol.
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(
2224 const Symbol_value<size>* lv_in,
2225 Symbol_value<size>* lv_out,
2227 const Output_sections& out_sections,
2228 const std::vector<Address>& out_offsets,
2229 const Symbol_table* symtab)
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());
2236 unsigned int shndx = lv_in->input_shndx(&is_ordinary);
2238 // Set the output symbol value.
2242 if (shndx == elfcpp::SHN_ABS || Symbol::is_common_shndx(shndx))
2243 lv_out->set_output_value(lv_in->input_value());
2246 this->error(_("unknown section index %u for local symbol %u"),
2248 lv_out->set_output_value(0);
2249 return This::CFLV_ERROR;
2254 if (shndx >= this->shnum())
2256 this->error(_("local symbol %u section index %u out of range"),
2258 lv_out->set_output_value(0);
2259 return This::CFLV_ERROR;
2262 Output_section* os = out_sections[shndx];
2263 Address secoffset = out_offsets[shndx];
2264 if (symtab->is_section_folded(this, shndx))
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,
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);
2277 // This could be a relaxed input section.
2278 if (secoffset == invalid_address)
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();
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;
2295 else if (secoffset == invalid_address)
2299 // This is a SHF_MERGE section or one which otherwise
2300 // requires special handling.
2301 if (shndx == this->discarded_eh_frame_shndx_)
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;
2309 else if (!lv_in->is_section_symbol())
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()));
2316 else if (!os->find_starting_output_address(this, shndx, &start))
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);
2328 Address relocatable_link_adjustment =
2329 relocatable ? os->address() : 0;
2330 lv_out->set_output_value(posd->address()
2331 - relocatable_link_adjustment);
2334 lv_out->set_output_value(os->address());
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
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(),
2348 lv_out->set_merged_symbol_value(msv);
2351 else if (lv_in->is_tls_symbol())
2352 lv_out->set_output_value(os->tls_offset()
2354 + lv_in->input_value());
2356 lv_out->set_output_value((relocatable ? 0 : os->address())
2358 + lv_in->input_value());
2360 return This::CFLV_OK;
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(
2377 const Symbol_value<size>* lv_in,
2378 Symbol_value<size>* lv_out,
2379 const Symbol_table* symtab)
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);
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.
2395 template<int size, bool big_endian>
2397 Sized_relobj_file<size, big_endian>::do_finalize_local_symbols(
2400 Symbol_table* symtab)
2402 gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
2404 const unsigned int loccount = this->local_symbol_count_;
2405 this->local_symbol_offset_ = off;
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());
2411 for (unsigned int i = 1; i < loccount; ++i)
2413 Symbol_value<size>* lv = &this->local_values_[i];
2415 Compute_final_local_value_status cflv_status =
2416 this->compute_final_local_value_internal(i, lv, lv, relocatable,
2417 out_sections, out_offsets,
2419 switch (cflv_status)
2422 if (!lv->is_output_symtab_index_set())
2424 lv->set_output_symtab_index(index);
2428 case CFLV_DISCARDED:
2439 // Set the output dynamic symbol table indexes for the local variables.
2441 template<int size, bool big_endian>
2443 Sized_relobj_file<size, big_endian>::do_set_local_dynsym_indexes(
2446 const unsigned int loccount = this->local_symbol_count_;
2447 for (unsigned int i = 1; i < loccount; ++i)
2449 Symbol_value<size>& lv(this->local_values_[i]);
2450 if (lv.needs_output_dynsym_entry())
2452 lv.set_output_dynsym_index(index);
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
2463 template<int size, bool big_endian>
2465 Sized_relobj_file<size, big_endian>::do_set_local_dynsym_offset(off_t off)
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_;
2472 // If Symbols_data is not NULL get the section flags from here otherwise
2473 // get it from the file.
2475 template<int size, bool big_endian>
2477 Sized_relobj_file<size, big_endian>::do_section_flags(unsigned int shndx)
2479 Symbols_data* sd = this->get_symbols_data();
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();
2487 // If sd is NULL, read the section header from the file.
2488 return this->elf_file_.section_flags(shndx);
2491 // Get the section's ent size from Symbols_data. Called by get_section_contents
2494 template<int size, bool big_endian>
2496 Sized_relobj_file<size, big_endian>::do_section_entsize(unsigned int shndx)
2498 Symbols_data* sd = this->get_symbols_data();
2499 gold_assert(sd != NULL);
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();
2507 // Write out the local symbols.
2509 template<int size, bool big_endian>
2511 Sized_relobj_file<size, big_endian>::write_local_symbols(
2513 const Stringpool* sympool,
2514 const Stringpool* dynpool,
2515 Output_symtab_xindex* symtab_xindex,
2516 Output_symtab_xindex* dynsym_xindex,
2519 const bool strip_all = parameters->options().strip_all();
2522 if (this->output_local_dynsym_count_ == 0)
2524 this->output_local_symbol_count_ = 0;
2527 gold_assert(this->symtab_shndx_ != -1U);
2528 if (this->symtab_shndx_ == 0)
2530 // This object has no symbols. Weird but legal.
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());
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);
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,
2555 const char* pnames = reinterpret_cast<const char*>(pnamesu);
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_,
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_,
2571 const Output_sections out_sections(this->output_sections());
2573 gold_assert(this->local_values_.size() == loccount);
2575 unsigned char* ov = oview;
2576 unsigned char* dyn_ov = dyn_oview;
2578 for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
2580 elfcpp::Sym<size, big_endian> isym(psyms);
2582 Symbol_value<size>& lv(this->local_values_[i]);
2585 unsigned int st_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
2589 gold_assert(st_shndx < out_sections.size());
2590 if (out_sections[st_shndx] == NULL)
2592 st_shndx = out_sections[st_shndx]->out_shndx();
2593 if (st_shndx >= elfcpp::SHN_LORESERVE)
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;
2603 // Write the symbol to the output symbol table.
2604 if (lv.has_output_symtab_entry())
2606 elfcpp::Sym_write<size, big_endian> osym(ov);
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);
2620 // Write the symbol to the output dynamic symbol table.
2621 if (lv.has_output_dynsym_entry())
2623 gold_assert(dyn_ov < dyn_oview + dyn_output_size);
2624 elfcpp::Sym_write<size, big_endian> osym(dyn_ov);
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);
2640 if (output_size > 0)
2642 gold_assert(ov - oview == output_size);
2643 of->write_output_view(symtab_off + this->local_symbol_offset_,
2644 output_size, oview);
2647 if (dyn_output_size > 0)
2649 gold_assert(dyn_ov - dyn_oview == dyn_output_size);
2650 of->write_output_view(this->local_dynsym_offset_, dyn_output_size,
2655 // Set *INFO to symbolic information about the offset OFFSET in the
2656 // section SHNDX. Return true if we found something, false if we
2659 template<int size, bool big_endian>
2661 Sized_relobj_file<size, big_endian>::get_symbol_location_info(
2664 Symbol_location_info* info)
2666 if (this->symtab_shndx_ == 0)
2669 section_size_type symbols_size;
2670 const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
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);
2681 const int sym_size = This::sym_size;
2682 const size_t count = symbols_size / sym_size;
2684 const unsigned char* p = symbols;
2685 for (size_t i = 0; i < count; ++i, p += sym_size)
2687 elfcpp::Sym<size, big_endian> sym(p);
2689 if (sym.get_st_type() == elfcpp::STT_FILE)
2691 if (sym.get_st_name() >= names_size)
2692 info->source_file = "(invalid)";
2694 info->source_file = symbol_names + sym.get_st_name();
2699 unsigned int st_shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
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())
2707 info->enclosing_symbol_type = sym.get_st_type();
2708 if (sym.get_st_name() > names_size)
2709 info->enclosing_symbol_name = "(invalid)";
2712 info->enclosing_symbol_name = symbol_names + sym.get_st_name();
2713 if (parameters->options().do_demangle())
2715 char* demangled_name = cplus_demangle(
2716 info->enclosing_symbol_name.c_str(),
2717 DMGL_ANSI | DMGL_PARAMS);
2718 if (demangled_name != NULL)
2720 info->enclosing_symbol_name.assign(demangled_name);
2721 free(demangled_name);
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.
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(
2742 Relobj* kept_object;
2743 unsigned int kept_shndx;
2744 if (this->get_kept_comdat_section(shndx, &kept_object, &kept_shndx))
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)
2753 return os->address() + offset;
2760 // Get symbol counts.
2762 template<int size, bool big_endian>
2764 Sized_relobj_file<size, big_endian>::do_get_global_symbol_counts(
2765 const Symbol_table*,
2769 *defined = this->defined_count_;
2771 for (typename Symbols::const_iterator p = this->symbols_.begin();
2772 p != this->symbols_.end();
2775 && (*p)->source() == Symbol::FROM_OBJECT
2776 && (*p)->object() == this
2777 && (*p)->is_defined())
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
2786 template<int size, bool big_endian>
2787 const unsigned char*
2788 Sized_relobj_file<size, big_endian>::do_decompressed_section_contents(
2790 section_size_type* plen,
2793 section_size_type buffer_size;
2794 const unsigned char* buffer = this->do_section_contents(shndx, &buffer_size,
2797 if (this->compressed_sections_ == NULL)
2799 *plen = buffer_size;
2804 Compressed_section_map::const_iterator p =
2805 this->compressed_sections_->find(shndx);
2806 if (p == this->compressed_sections_->end())
2808 *plen = buffer_size;
2813 section_size_type uncompressed_size = p->second.size;
2814 if (p->second.contents != NULL)
2816 *plen = uncompressed_size;
2818 return p->second.contents;
2821 unsigned char* uncompressed_data = new unsigned char[uncompressed_size];
2822 if (!decompress_input_section(buffer,
2826 this->error(_("could not decompress section %s"),
2827 this->do_section_name(shndx).c_str());
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;
2836 return uncompressed_data;
2839 // Discard any buffers of uncompressed sections. This is done
2840 // at the end of the Add_symbols task.
2842 template<int size, bool big_endian>
2844 Sized_relobj_file<size, big_endian>::do_discard_decompressed_sections()
2846 if (this->compressed_sections_ == NULL)
2849 for (Compressed_section_map::iterator p = this->compressed_sections_->begin();
2850 p != this->compressed_sections_->end();
2853 if (p->second.contents != NULL)
2855 delete[] p->second.contents;
2856 p->second.contents = NULL;
2861 // Input_objects methods.
2863 // Add a regular relocatable object to the list. Return false if this
2864 // object should be ignored.
2867 Input_objects::add_object(Object* obj)
2869 // Print the filename if the -t/--trace option is selected.
2870 if (parameters->options().trace())
2871 gold_info("%s", obj->name().c_str());
2873 if (!obj->is_dynamic())
2874 this->relobj_list_.push_back(static_cast<Relobj*>(obj));
2877 // See if this is a duplicate SONAME.
2878 Dynobj* dynobj = static_cast<Dynobj*>(obj);
2879 const char* soname = dynobj->soname();
2881 std::pair<Unordered_set<std::string>::iterator, bool> ins =
2882 this->sonames_.insert(soname);
2885 // We have already seen a dynamic object with this soname.
2889 this->dynobj_list_.push_back(dynobj);
2892 // Add this object to the cross-referencer if requested.
2893 if (parameters->options().user_set_print_symbol_counts()
2894 || parameters->options().cref())
2896 if (this->cref_ == NULL)
2897 this->cref_ = new Cref();
2898 this->cref_->add_object(obj);
2904 // For each dynamic object, record whether we've seen all of its
2905 // explicit dependencies.
2908 Input_objects::check_dynamic_dependencies() const
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();
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)
2920 if (this->sonames_.find(*pneeded) == this->sonames_.end())
2926 (*p)->set_has_unknown_needed_entries(!found_all);
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.
2933 && !issued_copy_dt_needed_error
2934 && (parameters->options().copy_dt_needed_entries()
2935 || parameters->options().add_needed()))
2937 const char* optname;
2938 if (parameters->options().copy_dt_needed_entries())
2939 optname = "--copy-dt-needed-entries";
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;
2949 // Start processing an archive.
2952 Input_objects::archive_start(Archive* archive)
2954 if (parameters->options().user_set_print_symbol_counts()
2955 || parameters->options().cref())
2957 if (this->cref_ == NULL)
2958 this->cref_ = new Cref();
2959 this->cref_->add_archive_start(archive);
2963 // Stop processing an archive.
2966 Input_objects::archive_stop(Archive* archive)
2968 if (parameters->options().user_set_print_symbol_counts()
2969 || parameters->options().cref())
2970 this->cref_->add_archive_stop(archive);
2973 // Print symbol counts
2976 Input_objects::print_symbol_counts(const Symbol_table* symtab) const
2978 if (parameters->options().user_set_print_symbol_counts()
2979 && this->cref_ != NULL)
2980 this->cref_->print_symbol_counts(symtab);
2983 // Print a cross reference table.
2986 Input_objects::print_cref(const Symbol_table* symtab, FILE* f) const
2988 if (parameters->options().cref() && this->cref_ != NULL)
2989 this->cref_->print_cref(symtab, f);
2992 // Relocate_info methods.
2994 // Return a string describing the location of a relocation when file
2995 // and lineno information is not available. This is only used in
2998 template<int size, bool big_endian>
3000 Relocate_info<size, big_endian>::location(size_t, off_t offset) const
3002 Sized_dwarf_line_info<size, big_endian> line_info(this->object);
3003 std::string ret = line_info.addr2line(this->data_shndx, offset, NULL);
3007 ret = this->object->name();
3009 Symbol_location_info info;
3010 if (this->object->get_symbol_location_info(this->data_shndx, offset, &info))
3012 if (!info.source_file.empty())
3015 ret += info.source_file;
3018 if (info.enclosing_symbol_type == elfcpp::STT_FUNC)
3019 ret += _("function ");
3020 ret += info.enclosing_symbol_name;
3025 ret += this->object->section_name(this->data_shndx);
3027 snprintf(buf, sizeof buf, "+0x%lx)", static_cast<long>(offset));
3032 } // End namespace gold.
3037 using namespace gold;
3039 // Read an ELF file with the header and return the appropriate
3040 // instance of Object.
3042 template<int size, bool big_endian>
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)
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]);
3053 gold_fatal(_("%s: unsupported ELF machine number %d"),
3054 name.c_str(), ehdr.get_e_machine());
3056 if (!parameters->target_valid())
3057 set_parameters_target(target);
3058 else if (target != ¶meters->target())
3060 if (punconfigured != NULL)
3061 *punconfigured = true;
3063 gold_error(_("%s: incompatible target"), name.c_str());
3067 return target->make_elf_object<size, big_endian>(name, input_file, offset,
3071 } // End anonymous namespace.
3076 // Return whether INPUT_FILE is an ELF object.
3079 is_elf_object(Input_file* input_file, off_t offset,
3080 const unsigned char** start, int* read_size)
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;
3087 const unsigned char* p = input_file->file().get_view(offset, 0, want,
3092 return elfcpp::Elf_recognizer::is_elf_file(p, want);
3095 // Read an ELF file and return the appropriate instance of 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)
3102 if (punconfigured != NULL)
3103 *punconfigured = false;
3106 bool big_endian = false;
3108 if (!elfcpp::Elf_recognizer::is_valid_header(p, bytes, &size,
3109 &big_endian, &error))
3111 gold_error(_("%s: %s"), name.c_str(), error.c_str());
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);
3124 if (punconfigured != NULL)
3125 *punconfigured = true;
3127 gold_error(_("%s: not configured to support "
3128 "32-bit big-endian object"),
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);
3140 if (punconfigured != NULL)
3141 *punconfigured = true;
3143 gold_error(_("%s: not configured to support "
3144 "32-bit little-endian object"),
3150 else if (size == 64)
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);
3159 if (punconfigured != NULL)
3160 *punconfigured = true;
3162 gold_error(_("%s: not configured to support "
3163 "64-bit big-endian object"),
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);
3175 if (punconfigured != NULL)
3176 *punconfigured = true;
3178 gold_error(_("%s: not configured to support "
3179 "64-bit little-endian object"),
3189 // Instantiate the templates we need.
3191 #ifdef HAVE_TARGET_32_LITTLE
3194 Object::read_section_data<32, false>(elfcpp::Elf_file<32, false, Object>*,
3195 Read_symbols_data*);
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;
3202 #ifdef HAVE_TARGET_32_BIG
3205 Object::read_section_data<32, true>(elfcpp::Elf_file<32, true, Object>*,
3206 Read_symbols_data*);
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;
3213 #ifdef HAVE_TARGET_64_LITTLE
3216 Object::read_section_data<64, false>(elfcpp::Elf_file<64, false, Object>*,
3217 Read_symbols_data*);
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;
3224 #ifdef HAVE_TARGET_64_BIG
3227 Object::read_section_data<64, true>(elfcpp::Elf_file<64, true, Object>*,
3228 Read_symbols_data*);
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;
3235 #ifdef HAVE_TARGET_32_LITTLE
3237 class Sized_relobj<32, false>;
3240 class Sized_relobj_file<32, false>;
3243 #ifdef HAVE_TARGET_32_BIG
3245 class Sized_relobj<32, true>;
3248 class Sized_relobj_file<32, true>;
3251 #ifdef HAVE_TARGET_64_LITTLE
3253 class Sized_relobj<64, false>;
3256 class Sized_relobj_file<64, false>;
3259 #ifdef HAVE_TARGET_64_BIG
3261 class Sized_relobj<64, true>;
3264 class Sized_relobj_file<64, true>;
3267 #ifdef HAVE_TARGET_32_LITTLE
3269 struct Relocate_info<32, false>;
3272 #ifdef HAVE_TARGET_32_BIG
3274 struct Relocate_info<32, true>;
3277 #ifdef HAVE_TARGET_64_LITTLE
3279 struct Relocate_info<64, false>;
3282 #ifdef HAVE_TARGET_64_BIG
3284 struct Relocate_info<64, true>;
3287 #ifdef HAVE_TARGET_32_LITTLE
3290 Xindex::initialize_symtab_xindex<32, false>(Object*, unsigned int);
3294 Xindex::read_symtab_xindex<32, false>(Object*, unsigned int,
3295 const unsigned char*);
3298 #ifdef HAVE_TARGET_32_BIG
3301 Xindex::initialize_symtab_xindex<32, true>(Object*, unsigned int);
3305 Xindex::read_symtab_xindex<32, true>(Object*, unsigned int,
3306 const unsigned char*);
3309 #ifdef HAVE_TARGET_64_LITTLE
3312 Xindex::initialize_symtab_xindex<64, false>(Object*, unsigned int);
3316 Xindex::read_symtab_xindex<64, false>(Object*, unsigned int,
3317 const unsigned char*);
3320 #ifdef HAVE_TARGET_64_BIG
3323 Xindex::initialize_symtab_xindex<64, true>(Object*, unsigned int);
3327 Xindex::read_symtab_xindex<64, true>(Object*, unsigned int,
3328 const unsigned char*);
3331 } // End namespace gold.