1 // object.cc -- support for an object file for linking in gold
3 // Copyright (C) 2006-2014 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
29 #include "libiberty.h"
32 #include "target-select.h"
33 #include "dwarf_reader.h"
42 #include "compressed_output.h"
43 #include "incremental.h"
48 // Struct Read_symbols_data.
50 // Destroy any remaining File_view objects and buffers of decompressed
53 Read_symbols_data::~Read_symbols_data()
55 if (this->section_headers != NULL)
56 delete this->section_headers;
57 if (this->section_names != NULL)
58 delete this->section_names;
59 if (this->symbols != NULL)
61 if (this->symbol_names != NULL)
62 delete this->symbol_names;
63 if (this->versym != NULL)
65 if (this->verdef != NULL)
67 if (this->verneed != NULL)
73 // Initialize the symtab_xindex_ array. Find the SHT_SYMTAB_SHNDX
74 // section and read it in. SYMTAB_SHNDX is the index of the symbol
75 // table we care about.
77 template<int size, bool big_endian>
79 Xindex::initialize_symtab_xindex(Object* object, unsigned int symtab_shndx)
81 if (!this->symtab_xindex_.empty())
84 gold_assert(symtab_shndx != 0);
86 // Look through the sections in reverse order, on the theory that it
87 // is more likely to be near the end than the beginning.
88 unsigned int i = object->shnum();
92 if (object->section_type(i) == elfcpp::SHT_SYMTAB_SHNDX
93 && this->adjust_shndx(object->section_link(i)) == symtab_shndx)
95 this->read_symtab_xindex<size, big_endian>(object, i, NULL);
100 object->error(_("missing SHT_SYMTAB_SHNDX section"));
103 // Read in the symtab_xindex_ array, given the section index of the
104 // SHT_SYMTAB_SHNDX section. If PSHDRS is not NULL, it points at the
107 template<int size, bool big_endian>
109 Xindex::read_symtab_xindex(Object* object, unsigned int xindex_shndx,
110 const unsigned char* pshdrs)
112 section_size_type bytecount;
113 const unsigned char* contents;
115 contents = object->section_contents(xindex_shndx, &bytecount, false);
118 const unsigned char* p = (pshdrs
120 * elfcpp::Elf_sizes<size>::shdr_size));
121 typename elfcpp::Shdr<size, big_endian> shdr(p);
122 bytecount = convert_to_section_size_type(shdr.get_sh_size());
123 contents = object->get_view(shdr.get_sh_offset(), bytecount, true, false);
126 gold_assert(this->symtab_xindex_.empty());
127 this->symtab_xindex_.reserve(bytecount / 4);
128 for (section_size_type i = 0; i < bytecount; i += 4)
130 unsigned int shndx = elfcpp::Swap<32, big_endian>::readval(contents + i);
131 // We preadjust the section indexes we save.
132 this->symtab_xindex_.push_back(this->adjust_shndx(shndx));
136 // Symbol symndx has a section of SHN_XINDEX; return the real section
140 Xindex::sym_xindex_to_shndx(Object* object, unsigned int symndx)
142 if (symndx >= this->symtab_xindex_.size())
144 object->error(_("symbol %u out of range for SHT_SYMTAB_SHNDX section"),
146 return elfcpp::SHN_UNDEF;
148 unsigned int shndx = this->symtab_xindex_[symndx];
149 if (shndx < elfcpp::SHN_LORESERVE || shndx >= object->shnum())
151 object->error(_("extended index for symbol %u out of range: %u"),
153 return elfcpp::SHN_UNDEF;
160 // Report an error for this object file. This is used by the
161 // elfcpp::Elf_file interface, and also called by the Object code
165 Object::error(const char* format, ...) const
168 va_start(args, format);
170 if (vasprintf(&buf, format, args) < 0)
173 gold_error(_("%s: %s"), this->name().c_str(), buf);
177 // Return a view of the contents of a section.
180 Object::section_contents(unsigned int shndx, section_size_type* plen,
182 { return this->do_section_contents(shndx, plen, cache); }
184 // Read the section data into SD. This is code common to Sized_relobj_file
185 // and Sized_dynobj, so we put it into Object.
187 template<int size, bool big_endian>
189 Object::read_section_data(elfcpp::Elf_file<size, big_endian, Object>* elf_file,
190 Read_symbols_data* sd)
192 const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
194 // Read the section headers.
195 const off_t shoff = elf_file->shoff();
196 const unsigned int shnum = this->shnum();
197 sd->section_headers = this->get_lasting_view(shoff, shnum * shdr_size,
200 // Read the section names.
201 const unsigned char* pshdrs = sd->section_headers->data();
202 const unsigned char* pshdrnames = pshdrs + elf_file->shstrndx() * shdr_size;
203 typename elfcpp::Shdr<size, big_endian> shdrnames(pshdrnames);
205 if (shdrnames.get_sh_type() != elfcpp::SHT_STRTAB)
206 this->error(_("section name section has wrong type: %u"),
207 static_cast<unsigned int>(shdrnames.get_sh_type()));
209 sd->section_names_size =
210 convert_to_section_size_type(shdrnames.get_sh_size());
211 sd->section_names = this->get_lasting_view(shdrnames.get_sh_offset(),
212 sd->section_names_size, false,
216 // If NAME is the name of a special .gnu.warning section, arrange for
217 // the warning to be issued. SHNDX is the section index. Return
218 // whether it is a warning section.
221 Object::handle_gnu_warning_section(const char* name, unsigned int shndx,
222 Symbol_table* symtab)
224 const char warn_prefix[] = ".gnu.warning.";
225 const int warn_prefix_len = sizeof warn_prefix - 1;
226 if (strncmp(name, warn_prefix, warn_prefix_len) == 0)
228 // Read the section contents to get the warning text. It would
229 // be nicer if we only did this if we have to actually issue a
230 // warning. Unfortunately, warnings are issued as we relocate
231 // sections. That means that we can not lock the object then,
232 // as we might try to issue the same warning multiple times
234 section_size_type len;
235 const unsigned char* contents = this->section_contents(shndx, &len,
239 const char* warning = name + warn_prefix_len;
240 contents = reinterpret_cast<const unsigned char*>(warning);
241 len = strlen(warning);
243 std::string warning(reinterpret_cast<const char*>(contents), len);
244 symtab->add_warning(name + warn_prefix_len, this, warning);
250 // If NAME is the name of the special section which indicates that
251 // this object was compiled with -fsplit-stack, mark it accordingly.
254 Object::handle_split_stack_section(const char* name)
256 if (strcmp(name, ".note.GNU-split-stack") == 0)
258 this->uses_split_stack_ = true;
261 if (strcmp(name, ".note.GNU-no-split-stack") == 0)
263 this->has_no_split_stack_ = true;
271 // To copy the symbols data read from the file to a local data structure.
272 // This function is called from do_layout only while doing garbage
276 Relobj::copy_symbols_data(Symbols_data* gc_sd, Read_symbols_data* sd,
277 unsigned int section_header_size)
279 gc_sd->section_headers_data =
280 new unsigned char[(section_header_size)];
281 memcpy(gc_sd->section_headers_data, sd->section_headers->data(),
282 section_header_size);
283 gc_sd->section_names_data =
284 new unsigned char[sd->section_names_size];
285 memcpy(gc_sd->section_names_data, sd->section_names->data(),
286 sd->section_names_size);
287 gc_sd->section_names_size = sd->section_names_size;
288 if (sd->symbols != NULL)
290 gc_sd->symbols_data =
291 new unsigned char[sd->symbols_size];
292 memcpy(gc_sd->symbols_data, sd->symbols->data(),
297 gc_sd->symbols_data = NULL;
299 gc_sd->symbols_size = sd->symbols_size;
300 gc_sd->external_symbols_offset = sd->external_symbols_offset;
301 if (sd->symbol_names != NULL)
303 gc_sd->symbol_names_data =
304 new unsigned char[sd->symbol_names_size];
305 memcpy(gc_sd->symbol_names_data, sd->symbol_names->data(),
306 sd->symbol_names_size);
310 gc_sd->symbol_names_data = NULL;
312 gc_sd->symbol_names_size = sd->symbol_names_size;
315 // This function determines if a particular section name must be included
316 // in the link. This is used during garbage collection to determine the
317 // roots of the worklist.
320 Relobj::is_section_name_included(const char* name)
322 if (is_prefix_of(".ctors", name)
323 || is_prefix_of(".dtors", name)
324 || is_prefix_of(".note", name)
325 || is_prefix_of(".init", name)
326 || is_prefix_of(".fini", name)
327 || is_prefix_of(".gcc_except_table", name)
328 || is_prefix_of(".jcr", name)
329 || is_prefix_of(".preinit_array", name)
330 || (is_prefix_of(".text", name)
331 && strstr(name, "personality"))
332 || (is_prefix_of(".data", name)
333 && strstr(name, "personality"))
334 || (is_prefix_of(".sdata", name)
335 && strstr(name, "personality"))
336 || (is_prefix_of(".gnu.linkonce.d", name)
337 && strstr(name, "personality"))
338 || (is_prefix_of(".rodata", name)
339 && strstr(name, "nptl_version")))
346 // Finalize the incremental relocation information. Allocates a block
347 // of relocation entries for each symbol, and sets the reloc_bases_
348 // array to point to the first entry in each block. If CLEAR_COUNTS
349 // is TRUE, also clear the per-symbol relocation counters.
352 Relobj::finalize_incremental_relocs(Layout* layout, bool clear_counts)
354 unsigned int nsyms = this->get_global_symbols()->size();
355 this->reloc_bases_ = new unsigned int[nsyms];
357 gold_assert(this->reloc_bases_ != NULL);
358 gold_assert(layout->incremental_inputs() != NULL);
360 unsigned int rindex = layout->incremental_inputs()->get_reloc_count();
361 for (unsigned int i = 0; i < nsyms; ++i)
363 this->reloc_bases_[i] = rindex;
364 rindex += this->reloc_counts_[i];
366 this->reloc_counts_[i] = 0;
368 layout->incremental_inputs()->set_reloc_count(rindex);
371 // Class Sized_relobj.
373 // Iterate over local symbols, calling a visitor class V for each GOT offset
374 // associated with a local symbol.
376 template<int size, bool big_endian>
378 Sized_relobj<size, big_endian>::do_for_all_local_got_entries(
379 Got_offset_list::Visitor* v) const
381 unsigned int nsyms = this->local_symbol_count();
382 for (unsigned int i = 0; i < nsyms; i++)
384 Local_got_offsets::const_iterator p = this->local_got_offsets_.find(i);
385 if (p != this->local_got_offsets_.end())
387 const Got_offset_list* got_offsets = p->second;
388 got_offsets->for_all_got_offsets(v);
393 // Get the address of an output section.
395 template<int size, bool big_endian>
397 Sized_relobj<size, big_endian>::do_output_section_address(
400 // If the input file is linked as --just-symbols, the output
401 // section address is the input section address.
402 if (this->just_symbols())
403 return this->section_address(shndx);
405 const Output_section* os = this->do_output_section(shndx);
406 gold_assert(os != NULL);
407 return os->address();
410 // Class Sized_relobj_file.
412 template<int size, bool big_endian>
413 Sized_relobj_file<size, big_endian>::Sized_relobj_file(
414 const std::string& name,
415 Input_file* input_file,
417 const elfcpp::Ehdr<size, big_endian>& ehdr)
418 : Sized_relobj<size, big_endian>(name, input_file, offset),
419 elf_file_(this, ehdr),
421 local_symbol_count_(0),
422 output_local_symbol_count_(0),
423 output_local_dynsym_count_(0),
426 local_symbol_offset_(0),
427 local_dynsym_offset_(0),
429 local_plt_offsets_(),
430 kept_comdat_sections_(),
431 has_eh_frame_(false),
432 discarded_eh_frame_shndx_(-1U),
434 deferred_layout_relocs_(),
435 compressed_sections_()
437 this->e_type_ = ehdr.get_e_type();
440 template<int size, bool big_endian>
441 Sized_relobj_file<size, big_endian>::~Sized_relobj_file()
445 // Set up an object file based on the file header. This sets up the
446 // section information.
448 template<int size, bool big_endian>
450 Sized_relobj_file<size, big_endian>::do_setup()
452 const unsigned int shnum = this->elf_file_.shnum();
453 this->set_shnum(shnum);
456 // Find the SHT_SYMTAB section, given the section headers. The ELF
457 // standard says that maybe in the future there can be more than one
458 // SHT_SYMTAB section. Until somebody figures out how that could
459 // work, we assume there is only one.
461 template<int size, bool big_endian>
463 Sized_relobj_file<size, big_endian>::find_symtab(const unsigned char* pshdrs)
465 const unsigned int shnum = this->shnum();
466 this->symtab_shndx_ = 0;
469 // Look through the sections in reverse order, since gas tends
470 // to put the symbol table at the end.
471 const unsigned char* p = pshdrs + shnum * This::shdr_size;
472 unsigned int i = shnum;
473 unsigned int xindex_shndx = 0;
474 unsigned int xindex_link = 0;
478 p -= This::shdr_size;
479 typename This::Shdr shdr(p);
480 if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB)
482 this->symtab_shndx_ = i;
483 if (xindex_shndx > 0 && xindex_link == i)
486 new Xindex(this->elf_file_.large_shndx_offset());
487 xindex->read_symtab_xindex<size, big_endian>(this,
490 this->set_xindex(xindex);
495 // Try to pick up the SHT_SYMTAB_SHNDX section, if there is
496 // one. This will work if it follows the SHT_SYMTAB
498 if (shdr.get_sh_type() == elfcpp::SHT_SYMTAB_SHNDX)
501 xindex_link = this->adjust_shndx(shdr.get_sh_link());
507 // Return the Xindex structure to use for object with lots of
510 template<int size, bool big_endian>
512 Sized_relobj_file<size, big_endian>::do_initialize_xindex()
514 gold_assert(this->symtab_shndx_ != -1U);
515 Xindex* xindex = new Xindex(this->elf_file_.large_shndx_offset());
516 xindex->initialize_symtab_xindex<size, big_endian>(this, this->symtab_shndx_);
520 // Return whether SHDR has the right type and flags to be a GNU
521 // .eh_frame section.
523 template<int size, bool big_endian>
525 Sized_relobj_file<size, big_endian>::check_eh_frame_flags(
526 const elfcpp::Shdr<size, big_endian>* shdr) const
528 elfcpp::Elf_Word sh_type = shdr->get_sh_type();
529 return ((sh_type == elfcpp::SHT_PROGBITS
530 || sh_type == elfcpp::SHT_X86_64_UNWIND)
531 && (shdr->get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
534 // Find the section header with the given name.
536 template<int size, bool big_endian>
539 const unsigned char* pshdrs,
542 section_size_type names_size,
543 const unsigned char* hdr) const
545 const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
546 const unsigned int shnum = this->shnum();
547 const unsigned char* hdr_end = pshdrs + shdr_size * shnum;
554 // We found HDR last time we were called, continue looking.
555 typename elfcpp::Shdr<size, big_endian> shdr(hdr);
556 sh_name = shdr.get_sh_name();
560 // Look for the next occurrence of NAME in NAMES.
561 // The fact that .shstrtab produced by current GNU tools is
562 // string merged means we shouldn't have both .not.foo and
563 // .foo in .shstrtab, and multiple .foo sections should all
564 // have the same sh_name. However, this is not guaranteed
565 // by the ELF spec and not all ELF object file producers may
567 size_t len = strlen(name) + 1;
568 const char *p = sh_name ? names + sh_name + len : names;
569 p = reinterpret_cast<const char*>(memmem(p, names_size - (p - names),
580 while (hdr < hdr_end)
582 typename elfcpp::Shdr<size, big_endian> shdr(hdr);
583 if (shdr.get_sh_name() == sh_name)
593 // Return whether there is a GNU .eh_frame section, given the section
594 // headers and the section names.
596 template<int size, bool big_endian>
598 Sized_relobj_file<size, big_endian>::find_eh_frame(
599 const unsigned char* pshdrs,
601 section_size_type names_size) const
603 const unsigned char* s = NULL;
607 s = this->template find_shdr<size, big_endian>(pshdrs, ".eh_frame",
608 names, names_size, s);
612 typename This::Shdr shdr(s);
613 if (this->check_eh_frame_flags(&shdr))
618 // Return TRUE if this is a section whose contents will be needed in the
619 // Add_symbols task. This function is only called for sections that have
620 // already passed the test in is_compressed_debug_section(), so we know
621 // that the section name begins with ".zdebug".
624 need_decompressed_section(const char* name)
626 // Skip over the ".zdebug" and a quick check for the "_".
631 #ifdef ENABLE_THREADS
632 // Decompressing these sections now will help only if we're
634 if (parameters->options().threads())
636 // We will need .zdebug_str if this is not an incremental link
637 // (i.e., we are processing string merge sections) or if we need
638 // to build a gdb index.
639 if ((!parameters->incremental() || parameters->options().gdb_index())
640 && strcmp(name, "str") == 0)
643 // We will need these other sections when building a gdb index.
644 if (parameters->options().gdb_index()
645 && (strcmp(name, "info") == 0
646 || strcmp(name, "types") == 0
647 || strcmp(name, "pubnames") == 0
648 || strcmp(name, "pubtypes") == 0
649 || strcmp(name, "ranges") == 0
650 || strcmp(name, "abbrev") == 0))
655 // Even when single-threaded, we will need .zdebug_str if this is
656 // not an incremental link and we are building a gdb index.
657 // Otherwise, we would decompress the section twice: once for
658 // string merge processing, and once for building the gdb index.
659 if (!parameters->incremental()
660 && parameters->options().gdb_index()
661 && strcmp(name, "str") == 0)
667 // Build a table for any compressed debug sections, mapping each section index
668 // to the uncompressed size and (if needed) the decompressed contents.
670 template<int size, bool big_endian>
671 Compressed_section_map*
672 build_compressed_section_map(
673 const unsigned char* pshdrs,
676 section_size_type names_size,
677 Sized_relobj_file<size, big_endian>* obj)
679 Compressed_section_map* uncompressed_map = new Compressed_section_map();
680 const unsigned int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
681 const unsigned char* p = pshdrs + shdr_size;
683 for (unsigned int i = 1; i < shnum; ++i, p += shdr_size)
685 typename elfcpp::Shdr<size, big_endian> shdr(p);
686 if (shdr.get_sh_type() == elfcpp::SHT_PROGBITS
687 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
689 if (shdr.get_sh_name() >= names_size)
691 obj->error(_("bad section name offset for section %u: %lu"),
692 i, static_cast<unsigned long>(shdr.get_sh_name()));
696 const char* name = names + shdr.get_sh_name();
697 if (is_compressed_debug_section(name))
699 section_size_type len;
700 const unsigned char* contents =
701 obj->section_contents(i, &len, false);
702 uint64_t uncompressed_size = get_uncompressed_size(contents, len);
703 Compressed_section_info info;
704 info.size = convert_to_section_size_type(uncompressed_size);
705 info.contents = NULL;
706 if (uncompressed_size != -1ULL)
708 unsigned char* uncompressed_data = NULL;
709 if (need_decompressed_section(name))
711 uncompressed_data = new unsigned char[uncompressed_size];
712 if (decompress_input_section(contents, len,
715 info.contents = uncompressed_data;
717 delete[] uncompressed_data;
719 (*uncompressed_map)[i] = info;
724 return uncompressed_map;
727 // Stash away info for a number of special sections.
728 // Return true if any of the sections found require local symbols to be read.
730 template<int size, bool big_endian>
732 Sized_relobj_file<size, big_endian>::do_find_special_sections(
733 Read_symbols_data* sd)
735 const unsigned char* const pshdrs = sd->section_headers->data();
736 const unsigned char* namesu = sd->section_names->data();
737 const char* names = reinterpret_cast<const char*>(namesu);
739 if (this->find_eh_frame(pshdrs, names, sd->section_names_size))
740 this->has_eh_frame_ = true;
742 if (memmem(names, sd->section_names_size, ".zdebug_", 8) != NULL)
743 this->compressed_sections_
744 = build_compressed_section_map(pshdrs, this->shnum(), names,
745 sd->section_names_size, this);
746 return (this->has_eh_frame_
747 || (!parameters->options().relocatable()
748 && parameters->options().gdb_index()
749 && (memmem(names, sd->section_names_size, "debug_info", 12) == 0
750 || memmem(names, sd->section_names_size, "debug_types",
754 // Read the sections and symbols from an object file.
756 template<int size, bool big_endian>
758 Sized_relobj_file<size, big_endian>::do_read_symbols(Read_symbols_data* sd)
760 this->base_read_symbols(sd);
763 // Read the sections and symbols from an object file. This is common
764 // code for all target-specific overrides of do_read_symbols().
766 template<int size, bool big_endian>
768 Sized_relobj_file<size, big_endian>::base_read_symbols(Read_symbols_data* sd)
770 this->read_section_data(&this->elf_file_, sd);
772 const unsigned char* const pshdrs = sd->section_headers->data();
774 this->find_symtab(pshdrs);
776 bool need_local_symbols = this->do_find_special_sections(sd);
779 sd->symbols_size = 0;
780 sd->external_symbols_offset = 0;
781 sd->symbol_names = NULL;
782 sd->symbol_names_size = 0;
784 if (this->symtab_shndx_ == 0)
786 // No symbol table. Weird but legal.
790 // Get the symbol table section header.
791 typename This::Shdr symtabshdr(pshdrs
792 + this->symtab_shndx_ * This::shdr_size);
793 gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
795 // If this object has a .eh_frame section, or if building a .gdb_index
796 // section and there is debug info, we need all the symbols.
797 // Otherwise we only need the external symbols. While it would be
798 // simpler to just always read all the symbols, I've seen object
799 // files with well over 2000 local symbols, which for a 64-bit
800 // object file format is over 5 pages that we don't need to read
803 const int sym_size = This::sym_size;
804 const unsigned int loccount = symtabshdr.get_sh_info();
805 this->local_symbol_count_ = loccount;
806 this->local_values_.resize(loccount);
807 section_offset_type locsize = loccount * sym_size;
808 off_t dataoff = symtabshdr.get_sh_offset();
809 section_size_type datasize =
810 convert_to_section_size_type(symtabshdr.get_sh_size());
811 off_t extoff = dataoff + locsize;
812 section_size_type extsize = datasize - locsize;
814 off_t readoff = need_local_symbols ? dataoff : extoff;
815 section_size_type readsize = need_local_symbols ? datasize : extsize;
819 // No external symbols. Also weird but also legal.
823 File_view* fvsymtab = this->get_lasting_view(readoff, readsize, true, false);
825 // Read the section header for the symbol names.
826 unsigned int strtab_shndx = this->adjust_shndx(symtabshdr.get_sh_link());
827 if (strtab_shndx >= this->shnum())
829 this->error(_("invalid symbol table name index: %u"), strtab_shndx);
832 typename This::Shdr strtabshdr(pshdrs + strtab_shndx * This::shdr_size);
833 if (strtabshdr.get_sh_type() != elfcpp::SHT_STRTAB)
835 this->error(_("symbol table name section has wrong type: %u"),
836 static_cast<unsigned int>(strtabshdr.get_sh_type()));
840 // Read the symbol names.
841 File_view* fvstrtab = this->get_lasting_view(strtabshdr.get_sh_offset(),
842 strtabshdr.get_sh_size(),
845 sd->symbols = fvsymtab;
846 sd->symbols_size = readsize;
847 sd->external_symbols_offset = need_local_symbols ? locsize : 0;
848 sd->symbol_names = fvstrtab;
849 sd->symbol_names_size =
850 convert_to_section_size_type(strtabshdr.get_sh_size());
853 // Return the section index of symbol SYM. Set *VALUE to its value in
854 // the object file. Set *IS_ORDINARY if this is an ordinary section
855 // index, not a special code between SHN_LORESERVE and SHN_HIRESERVE.
856 // Note that for a symbol which is not defined in this object file,
857 // this will set *VALUE to 0 and return SHN_UNDEF; it will not return
858 // the final value of the symbol in the link.
860 template<int size, bool big_endian>
862 Sized_relobj_file<size, big_endian>::symbol_section_and_value(unsigned int sym,
866 section_size_type symbols_size;
867 const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
871 const size_t count = symbols_size / This::sym_size;
872 gold_assert(sym < count);
874 elfcpp::Sym<size, big_endian> elfsym(symbols + sym * This::sym_size);
875 *value = elfsym.get_st_value();
877 return this->adjust_sym_shndx(sym, elfsym.get_st_shndx(), is_ordinary);
880 // Return whether to include a section group in the link. LAYOUT is
881 // used to keep track of which section groups we have already seen.
882 // INDEX is the index of the section group and SHDR is the section
883 // header. If we do not want to include this group, we set bits in
884 // OMIT for each section which should be discarded.
886 template<int size, bool big_endian>
888 Sized_relobj_file<size, big_endian>::include_section_group(
889 Symbol_table* symtab,
893 const unsigned char* shdrs,
894 const char* section_names,
895 section_size_type section_names_size,
896 std::vector<bool>* omit)
898 // Read the section contents.
899 typename This::Shdr shdr(shdrs + index * This::shdr_size);
900 const unsigned char* pcon = this->get_view(shdr.get_sh_offset(),
901 shdr.get_sh_size(), true, false);
902 const elfcpp::Elf_Word* pword =
903 reinterpret_cast<const elfcpp::Elf_Word*>(pcon);
905 // The first word contains flags. We only care about COMDAT section
906 // groups. Other section groups are always included in the link
907 // just like ordinary sections.
908 elfcpp::Elf_Word flags = elfcpp::Swap<32, big_endian>::readval(pword);
910 // Look up the group signature, which is the name of a symbol. ELF
911 // uses a symbol name because some group signatures are long, and
912 // the name is generally already in the symbol table, so it makes
913 // sense to put the long string just once in .strtab rather than in
914 // both .strtab and .shstrtab.
916 // Get the appropriate symbol table header (this will normally be
917 // the single SHT_SYMTAB section, but in principle it need not be).
918 const unsigned int link = this->adjust_shndx(shdr.get_sh_link());
919 typename This::Shdr symshdr(this, this->elf_file_.section_header(link));
921 // Read the symbol table entry.
922 unsigned int symndx = shdr.get_sh_info();
923 if (symndx >= symshdr.get_sh_size() / This::sym_size)
925 this->error(_("section group %u info %u out of range"),
929 off_t symoff = symshdr.get_sh_offset() + symndx * This::sym_size;
930 const unsigned char* psym = this->get_view(symoff, This::sym_size, true,
932 elfcpp::Sym<size, big_endian> sym(psym);
934 // Read the symbol table names.
935 section_size_type symnamelen;
936 const unsigned char* psymnamesu;
937 psymnamesu = this->section_contents(this->adjust_shndx(symshdr.get_sh_link()),
939 const char* psymnames = reinterpret_cast<const char*>(psymnamesu);
941 // Get the section group signature.
942 if (sym.get_st_name() >= symnamelen)
944 this->error(_("symbol %u name offset %u out of range"),
945 symndx, sym.get_st_name());
949 std::string signature(psymnames + sym.get_st_name());
951 // It seems that some versions of gas will create a section group
952 // associated with a section symbol, and then fail to give a name to
953 // the section symbol. In such a case, use the name of the section.
954 if (signature[0] == '\0' && sym.get_st_type() == elfcpp::STT_SECTION)
957 unsigned int sym_shndx = this->adjust_sym_shndx(symndx,
960 if (!is_ordinary || sym_shndx >= this->shnum())
962 this->error(_("symbol %u invalid section index %u"),
966 typename This::Shdr member_shdr(shdrs + sym_shndx * This::shdr_size);
967 if (member_shdr.get_sh_name() < section_names_size)
968 signature = section_names + member_shdr.get_sh_name();
971 // Record this section group in the layout, and see whether we've already
972 // seen one with the same signature.
975 Kept_section* kept_section = NULL;
977 if ((flags & elfcpp::GRP_COMDAT) == 0)
979 include_group = true;
984 include_group = layout->find_or_add_kept_section(signature,
986 true, &kept_section);
990 if (is_comdat && include_group)
992 Incremental_inputs* incremental_inputs = layout->incremental_inputs();
993 if (incremental_inputs != NULL)
994 incremental_inputs->report_comdat_group(this, signature.c_str());
997 size_t count = shdr.get_sh_size() / sizeof(elfcpp::Elf_Word);
999 std::vector<unsigned int> shndxes;
1000 bool relocate_group = include_group && parameters->options().relocatable();
1002 shndxes.reserve(count - 1);
1004 for (size_t i = 1; i < count; ++i)
1006 elfcpp::Elf_Word shndx =
1007 this->adjust_shndx(elfcpp::Swap<32, big_endian>::readval(pword + i));
1010 shndxes.push_back(shndx);
1012 if (shndx >= this->shnum())
1014 this->error(_("section %u in section group %u out of range"),
1019 // Check for an earlier section number, since we're going to get
1020 // it wrong--we may have already decided to include the section.
1022 this->error(_("invalid section group %u refers to earlier section %u"),
1025 // Get the name of the member section.
1026 typename This::Shdr member_shdr(shdrs + shndx * This::shdr_size);
1027 if (member_shdr.get_sh_name() >= section_names_size)
1029 // This is an error, but it will be diagnosed eventually
1030 // in do_layout, so we don't need to do anything here but
1034 std::string mname(section_names + member_shdr.get_sh_name());
1039 kept_section->add_comdat_section(mname, shndx,
1040 member_shdr.get_sh_size());
1044 (*omit)[shndx] = true;
1048 Relobj* kept_object = kept_section->object();
1049 if (kept_section->is_comdat())
1051 // Find the corresponding kept section, and store
1052 // that info in the discarded section table.
1053 unsigned int kept_shndx;
1055 if (kept_section->find_comdat_section(mname, &kept_shndx,
1058 // We don't keep a mapping for this section if
1059 // it has a different size. The mapping is only
1060 // used for relocation processing, and we don't
1061 // want to treat the sections as similar if the
1062 // sizes are different. Checking the section
1063 // size is the approach used by the GNU linker.
1064 if (kept_size == member_shdr.get_sh_size())
1065 this->set_kept_comdat_section(shndx, kept_object,
1071 // The existing section is a linkonce section. Add
1072 // a mapping if there is exactly one section in the
1073 // group (which is true when COUNT == 2) and if it
1074 // is the same size.
1076 && (kept_section->linkonce_size()
1077 == member_shdr.get_sh_size()))
1078 this->set_kept_comdat_section(shndx, kept_object,
1079 kept_section->shndx());
1086 layout->layout_group(symtab, this, index, name, signature.c_str(),
1087 shdr, flags, &shndxes);
1089 return include_group;
1092 // Whether to include a linkonce section in the link. NAME is the
1093 // name of the section and SHDR is the section header.
1095 // Linkonce sections are a GNU extension implemented in the original
1096 // GNU linker before section groups were defined. The semantics are
1097 // that we only include one linkonce section with a given name. The
1098 // name of a linkonce section is normally .gnu.linkonce.T.SYMNAME,
1099 // where T is the type of section and SYMNAME is the name of a symbol.
1100 // In an attempt to make linkonce sections interact well with section
1101 // groups, we try to identify SYMNAME and use it like a section group
1102 // signature. We want to block section groups with that signature,
1103 // but not other linkonce sections with that signature. We also use
1104 // the full name of the linkonce section as a normal section group
1107 template<int size, bool big_endian>
1109 Sized_relobj_file<size, big_endian>::include_linkonce_section(
1113 const elfcpp::Shdr<size, big_endian>& shdr)
1115 typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
1116 // In general the symbol name we want will be the string following
1117 // the last '.'. However, we have to handle the case of
1118 // .gnu.linkonce.t.__i686.get_pc_thunk.bx, which was generated by
1119 // some versions of gcc. So we use a heuristic: if the name starts
1120 // with ".gnu.linkonce.t.", we use everything after that. Otherwise
1121 // we look for the last '.'. We can't always simply skip
1122 // ".gnu.linkonce.X", because we have to deal with cases like
1123 // ".gnu.linkonce.d.rel.ro.local".
1124 const char* const linkonce_t = ".gnu.linkonce.t.";
1125 const char* symname;
1126 if (strncmp(name, linkonce_t, strlen(linkonce_t)) == 0)
1127 symname = name + strlen(linkonce_t);
1129 symname = strrchr(name, '.') + 1;
1130 std::string sig1(symname);
1131 std::string sig2(name);
1132 Kept_section* kept1;
1133 Kept_section* kept2;
1134 bool include1 = layout->find_or_add_kept_section(sig1, this, index, false,
1136 bool include2 = layout->find_or_add_kept_section(sig2, this, index, false,
1141 // We are not including this section because we already saw the
1142 // name of the section as a signature. This normally implies
1143 // that the kept section is another linkonce section. If it is
1144 // the same size, record it as the section which corresponds to
1146 if (kept2->object() != NULL
1147 && !kept2->is_comdat()
1148 && kept2->linkonce_size() == sh_size)
1149 this->set_kept_comdat_section(index, kept2->object(), kept2->shndx());
1153 // The section is being discarded on the basis of its symbol
1154 // name. This means that the corresponding kept section was
1155 // part of a comdat group, and it will be difficult to identify
1156 // the specific section within that group that corresponds to
1157 // this linkonce section. We'll handle the simple case where
1158 // the group has only one member section. Otherwise, it's not
1159 // worth the effort.
1160 unsigned int kept_shndx;
1162 if (kept1->object() != NULL
1163 && kept1->is_comdat()
1164 && kept1->find_single_comdat_section(&kept_shndx, &kept_size)
1165 && kept_size == sh_size)
1166 this->set_kept_comdat_section(index, kept1->object(), kept_shndx);
1170 kept1->set_linkonce_size(sh_size);
1171 kept2->set_linkonce_size(sh_size);
1174 return include1 && include2;
1177 // Layout an input section.
1179 template<int size, bool big_endian>
1181 Sized_relobj_file<size, big_endian>::layout_section(
1185 const typename This::Shdr& shdr,
1186 unsigned int reloc_shndx,
1187 unsigned int reloc_type)
1190 Output_section* os = layout->layout(this, shndx, name, shdr,
1191 reloc_shndx, reloc_type, &offset);
1193 this->output_sections()[shndx] = os;
1195 this->section_offsets()[shndx] = invalid_address;
1197 this->section_offsets()[shndx] = convert_types<Address, off_t>(offset);
1199 // If this section requires special handling, and if there are
1200 // relocs that apply to it, then we must do the special handling
1201 // before we apply the relocs.
1202 if (offset == -1 && reloc_shndx != 0)
1203 this->set_relocs_must_follow_section_writes();
1206 // Layout an input .eh_frame section.
1208 template<int size, bool big_endian>
1210 Sized_relobj_file<size, big_endian>::layout_eh_frame_section(
1212 const unsigned char* symbols_data,
1213 section_size_type symbols_size,
1214 const unsigned char* symbol_names_data,
1215 section_size_type symbol_names_size,
1217 const typename This::Shdr& shdr,
1218 unsigned int reloc_shndx,
1219 unsigned int reloc_type)
1221 gold_assert(this->has_eh_frame_);
1224 Output_section* os = layout->layout_eh_frame(this,
1234 this->output_sections()[shndx] = os;
1235 if (os == NULL || offset == -1)
1237 // An object can contain at most one section holding exception
1238 // frame information.
1239 gold_assert(this->discarded_eh_frame_shndx_ == -1U);
1240 this->discarded_eh_frame_shndx_ = shndx;
1241 this->section_offsets()[shndx] = invalid_address;
1244 this->section_offsets()[shndx] = convert_types<Address, off_t>(offset);
1246 // If this section requires special handling, and if there are
1247 // relocs that aply to it, then we must do the special handling
1248 // before we apply the relocs.
1249 if (os != NULL && offset == -1 && reloc_shndx != 0)
1250 this->set_relocs_must_follow_section_writes();
1253 // Lay out the input sections. We walk through the sections and check
1254 // whether they should be included in the link. If they should, we
1255 // pass them to the Layout object, which will return an output section
1257 // This function is called twice sometimes, two passes, when mapping
1258 // of input sections to output sections must be delayed.
1259 // This is true for the following :
1260 // * Garbage collection (--gc-sections): Some input sections will be
1261 // discarded and hence the assignment must wait until the second pass.
1262 // In the first pass, it is for setting up some sections as roots to
1263 // a work-list for --gc-sections and to do comdat processing.
1264 // * Identical Code Folding (--icf=<safe,all>): Some input sections
1265 // will be folded and hence the assignment must wait.
1266 // * Using plugins to map some sections to unique segments: Mapping
1267 // some sections to unique segments requires mapping them to unique
1268 // output sections too. This can be done via plugins now and this
1269 // information is not available in the first pass.
1271 template<int size, bool big_endian>
1273 Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
1275 Read_symbols_data* sd)
1277 const unsigned int shnum = this->shnum();
1279 /* Should this function be called twice? */
1280 bool is_two_pass = (parameters->options().gc_sections()
1281 || parameters->options().icf_enabled()
1282 || layout->is_unique_segment_for_sections_specified());
1284 /* Only one of is_pass_one and is_pass_two is true. Both are false when
1285 a two-pass approach is not needed. */
1286 bool is_pass_one = false;
1287 bool is_pass_two = false;
1289 Symbols_data* gc_sd = NULL;
1291 /* Check if do_layout needs to be two-pass. If so, find out which pass
1292 should happen. In the first pass, the data in sd is saved to be used
1293 later in the second pass. */
1296 gc_sd = this->get_symbols_data();
1299 gold_assert(sd != NULL);
1304 if (parameters->options().gc_sections())
1305 gold_assert(symtab->gc()->is_worklist_ready());
1306 if (parameters->options().icf_enabled())
1307 gold_assert(symtab->icf()->is_icf_ready());
1317 // During garbage collection save the symbols data to use it when
1318 // re-entering this function.
1319 gc_sd = new Symbols_data;
1320 this->copy_symbols_data(gc_sd, sd, This::shdr_size * shnum);
1321 this->set_symbols_data(gc_sd);
1324 const unsigned char* section_headers_data = NULL;
1325 section_size_type section_names_size;
1326 const unsigned char* symbols_data = NULL;
1327 section_size_type symbols_size;
1328 const unsigned char* symbol_names_data = NULL;
1329 section_size_type symbol_names_size;
1333 section_headers_data = gc_sd->section_headers_data;
1334 section_names_size = gc_sd->section_names_size;
1335 symbols_data = gc_sd->symbols_data;
1336 symbols_size = gc_sd->symbols_size;
1337 symbol_names_data = gc_sd->symbol_names_data;
1338 symbol_names_size = gc_sd->symbol_names_size;
1342 section_headers_data = sd->section_headers->data();
1343 section_names_size = sd->section_names_size;
1344 if (sd->symbols != NULL)
1345 symbols_data = sd->symbols->data();
1346 symbols_size = sd->symbols_size;
1347 if (sd->symbol_names != NULL)
1348 symbol_names_data = sd->symbol_names->data();
1349 symbol_names_size = sd->symbol_names_size;
1352 // Get the section headers.
1353 const unsigned char* shdrs = section_headers_data;
1354 const unsigned char* pshdrs;
1356 // Get the section names.
1357 const unsigned char* pnamesu = (is_two_pass
1358 ? gc_sd->section_names_data
1359 : sd->section_names->data());
1361 const char* pnames = reinterpret_cast<const char*>(pnamesu);
1363 // If any input files have been claimed by plugins, we need to defer
1364 // actual layout until the replacement files have arrived.
1365 const bool should_defer_layout =
1366 (parameters->options().has_plugins()
1367 && parameters->options().plugins()->should_defer_layout());
1368 unsigned int num_sections_to_defer = 0;
1370 // For each section, record the index of the reloc section if any.
1371 // Use 0 to mean that there is no reloc section, -1U to mean that
1372 // there is more than one.
1373 std::vector<unsigned int> reloc_shndx(shnum, 0);
1374 std::vector<unsigned int> reloc_type(shnum, elfcpp::SHT_NULL);
1375 // Skip the first, dummy, section.
1376 pshdrs = shdrs + This::shdr_size;
1377 for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1379 typename This::Shdr shdr(pshdrs);
1381 // Count the number of sections whose layout will be deferred.
1382 if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1383 ++num_sections_to_defer;
1385 unsigned int sh_type = shdr.get_sh_type();
1386 if (sh_type == elfcpp::SHT_REL || sh_type == elfcpp::SHT_RELA)
1388 unsigned int target_shndx = this->adjust_shndx(shdr.get_sh_info());
1389 if (target_shndx == 0 || target_shndx >= shnum)
1391 this->error(_("relocation section %u has bad info %u"),
1396 if (reloc_shndx[target_shndx] != 0)
1397 reloc_shndx[target_shndx] = -1U;
1400 reloc_shndx[target_shndx] = i;
1401 reloc_type[target_shndx] = sh_type;
1406 Output_sections& out_sections(this->output_sections());
1407 std::vector<Address>& out_section_offsets(this->section_offsets());
1411 out_sections.resize(shnum);
1412 out_section_offsets.resize(shnum);
1415 // If we are only linking for symbols, then there is nothing else to
1417 if (this->input_file()->just_symbols())
1421 delete sd->section_headers;
1422 sd->section_headers = NULL;
1423 delete sd->section_names;
1424 sd->section_names = NULL;
1429 if (num_sections_to_defer > 0)
1431 parameters->options().plugins()->add_deferred_layout_object(this);
1432 this->deferred_layout_.reserve(num_sections_to_defer);
1435 // Whether we've seen a .note.GNU-stack section.
1436 bool seen_gnu_stack = false;
1437 // The flags of a .note.GNU-stack section.
1438 uint64_t gnu_stack_flags = 0;
1440 // Keep track of which sections to omit.
1441 std::vector<bool> omit(shnum, false);
1443 // Keep track of reloc sections when emitting relocations.
1444 const bool relocatable = parameters->options().relocatable();
1445 const bool emit_relocs = (relocatable
1446 || parameters->options().emit_relocs());
1447 std::vector<unsigned int> reloc_sections;
1449 // Keep track of .eh_frame sections.
1450 std::vector<unsigned int> eh_frame_sections;
1452 // Keep track of .debug_info and .debug_types sections.
1453 std::vector<unsigned int> debug_info_sections;
1454 std::vector<unsigned int> debug_types_sections;
1456 // Skip the first, dummy, section.
1457 pshdrs = shdrs + This::shdr_size;
1458 for (unsigned int i = 1; i < shnum; ++i, pshdrs += This::shdr_size)
1460 typename This::Shdr shdr(pshdrs);
1462 if (shdr.get_sh_name() >= section_names_size)
1464 this->error(_("bad section name offset for section %u: %lu"),
1465 i, static_cast<unsigned long>(shdr.get_sh_name()));
1469 const char* name = pnames + shdr.get_sh_name();
1473 if (this->handle_gnu_warning_section(name, i, symtab))
1475 if (!relocatable && !parameters->options().shared())
1479 // The .note.GNU-stack section is special. It gives the
1480 // protection flags that this object file requires for the stack
1482 if (strcmp(name, ".note.GNU-stack") == 0)
1484 seen_gnu_stack = true;
1485 gnu_stack_flags |= shdr.get_sh_flags();
1489 // The .note.GNU-split-stack section is also special. It
1490 // indicates that the object was compiled with
1492 if (this->handle_split_stack_section(name))
1494 if (!relocatable && !parameters->options().shared())
1498 // Skip attributes section.
1499 if (parameters->target().is_attributes_section(name))
1504 bool discard = omit[i];
1507 if (shdr.get_sh_type() == elfcpp::SHT_GROUP)
1509 if (!this->include_section_group(symtab, layout, i, name,
1515 else if ((shdr.get_sh_flags() & elfcpp::SHF_GROUP) == 0
1516 && Layout::is_linkonce(name))
1518 if (!this->include_linkonce_section(layout, i, name, shdr))
1523 // Add the section to the incremental inputs layout.
1524 Incremental_inputs* incremental_inputs = layout->incremental_inputs();
1525 if (incremental_inputs != NULL
1527 && can_incremental_update(shdr.get_sh_type()))
1529 off_t sh_size = shdr.get_sh_size();
1530 section_size_type uncompressed_size;
1531 if (this->section_is_compressed(i, &uncompressed_size))
1532 sh_size = uncompressed_size;
1533 incremental_inputs->report_input_section(this, i, name, sh_size);
1538 // Do not include this section in the link.
1539 out_sections[i] = NULL;
1540 out_section_offsets[i] = invalid_address;
1545 if (is_pass_one && parameters->options().gc_sections())
1547 if (this->is_section_name_included(name)
1548 || layout->keep_input_section (this, name)
1549 || shdr.get_sh_type() == elfcpp::SHT_INIT_ARRAY
1550 || shdr.get_sh_type() == elfcpp::SHT_FINI_ARRAY)
1552 symtab->gc()->worklist().push(Section_id(this, i));
1554 // If the section name XXX can be represented as a C identifier
1555 // it cannot be discarded if there are references to
1556 // __start_XXX and __stop_XXX symbols. These need to be
1557 // specially handled.
1558 if (is_cident(name))
1560 symtab->gc()->add_cident_section(name, Section_id(this, i));
1564 // When doing a relocatable link we are going to copy input
1565 // reloc sections into the output. We only want to copy the
1566 // ones associated with sections which are not being discarded.
1567 // However, we don't know that yet for all sections. So save
1568 // reloc sections and process them later. Garbage collection is
1569 // not triggered when relocatable code is desired.
1571 && (shdr.get_sh_type() == elfcpp::SHT_REL
1572 || shdr.get_sh_type() == elfcpp::SHT_RELA))
1574 reloc_sections.push_back(i);
1578 if (relocatable && shdr.get_sh_type() == elfcpp::SHT_GROUP)
1581 // The .eh_frame section is special. It holds exception frame
1582 // information that we need to read in order to generate the
1583 // exception frame header. We process these after all the other
1584 // sections so that the exception frame reader can reliably
1585 // determine which sections are being discarded, and discard the
1586 // corresponding information.
1588 && strcmp(name, ".eh_frame") == 0
1589 && this->check_eh_frame_flags(&shdr))
1593 out_sections[i] = reinterpret_cast<Output_section*>(1);
1594 out_section_offsets[i] = invalid_address;
1596 else if (should_defer_layout)
1597 this->deferred_layout_.push_back(Deferred_layout(i, name,
1602 eh_frame_sections.push_back(i);
1606 if (is_pass_two && parameters->options().gc_sections())
1608 // This is executed during the second pass of garbage
1609 // collection. do_layout has been called before and some
1610 // sections have been already discarded. Simply ignore
1611 // such sections this time around.
1612 if (out_sections[i] == NULL)
1614 gold_assert(out_section_offsets[i] == invalid_address);
1617 if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1618 && symtab->gc()->is_section_garbage(this, i))
1620 if (parameters->options().print_gc_sections())
1621 gold_info(_("%s: removing unused section from '%s'"
1623 program_name, this->section_name(i).c_str(),
1624 this->name().c_str());
1625 out_sections[i] = NULL;
1626 out_section_offsets[i] = invalid_address;
1631 if (is_pass_two && parameters->options().icf_enabled())
1633 if (out_sections[i] == NULL)
1635 gold_assert(out_section_offsets[i] == invalid_address);
1638 if (((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0)
1639 && symtab->icf()->is_section_folded(this, i))
1641 if (parameters->options().print_icf_sections())
1644 symtab->icf()->get_folded_section(this, i);
1645 Relobj* folded_obj =
1646 reinterpret_cast<Relobj*>(folded.first);
1647 gold_info(_("%s: ICF folding section '%s' in file '%s' "
1648 "into '%s' in file '%s'"),
1649 program_name, this->section_name(i).c_str(),
1650 this->name().c_str(),
1651 folded_obj->section_name(folded.second).c_str(),
1652 folded_obj->name().c_str());
1654 out_sections[i] = NULL;
1655 out_section_offsets[i] = invalid_address;
1660 // Defer layout here if input files are claimed by plugins. When gc
1661 // is turned on this function is called twice. For the second call
1662 // should_defer_layout should be false.
1663 if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1665 gold_assert(!is_pass_two);
1666 this->deferred_layout_.push_back(Deferred_layout(i, name,
1670 // Put dummy values here; real values will be supplied by
1671 // do_layout_deferred_sections.
1672 out_sections[i] = reinterpret_cast<Output_section*>(2);
1673 out_section_offsets[i] = invalid_address;
1677 // During gc_pass_two if a section that was previously deferred is
1678 // found, do not layout the section as layout_deferred_sections will
1679 // do it later from gold.cc.
1681 && (out_sections[i] == reinterpret_cast<Output_section*>(2)))
1686 // This is during garbage collection. The out_sections are
1687 // assigned in the second call to this function.
1688 out_sections[i] = reinterpret_cast<Output_section*>(1);
1689 out_section_offsets[i] = invalid_address;
1693 // When garbage collection is switched on the actual layout
1694 // only happens in the second call.
1695 this->layout_section(layout, i, name, shdr, reloc_shndx[i],
1698 // When generating a .gdb_index section, we do additional
1699 // processing of .debug_info and .debug_types sections after all
1700 // the other sections for the same reason as above.
1702 && parameters->options().gdb_index()
1703 && !(shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
1705 if (strcmp(name, ".debug_info") == 0
1706 || strcmp(name, ".zdebug_info") == 0)
1707 debug_info_sections.push_back(i);
1708 else if (strcmp(name, ".debug_types") == 0
1709 || strcmp(name, ".zdebug_types") == 0)
1710 debug_types_sections.push_back(i);
1716 layout->layout_gnu_stack(seen_gnu_stack, gnu_stack_flags, this);
1718 // Handle the .eh_frame sections after the other sections.
1719 gold_assert(!is_pass_one || eh_frame_sections.empty());
1720 for (std::vector<unsigned int>::const_iterator p = eh_frame_sections.begin();
1721 p != eh_frame_sections.end();
1724 unsigned int i = *p;
1725 const unsigned char* pshdr;
1726 pshdr = section_headers_data + i * This::shdr_size;
1727 typename This::Shdr shdr(pshdr);
1729 this->layout_eh_frame_section(layout,
1740 // When doing a relocatable link handle the reloc sections at the
1741 // end. Garbage collection and Identical Code Folding is not
1742 // turned on for relocatable code.
1744 this->size_relocatable_relocs();
1746 gold_assert(!is_two_pass || reloc_sections.empty());
1748 for (std::vector<unsigned int>::const_iterator p = reloc_sections.begin();
1749 p != reloc_sections.end();
1752 unsigned int i = *p;
1753 const unsigned char* pshdr;
1754 pshdr = section_headers_data + i * This::shdr_size;
1755 typename This::Shdr shdr(pshdr);
1757 unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1758 if (data_shndx >= shnum)
1760 // We already warned about this above.
1764 Output_section* data_section = out_sections[data_shndx];
1765 if (data_section == reinterpret_cast<Output_section*>(2))
1767 // The layout for the data section was deferred, so we need
1768 // to defer the relocation section, too.
1769 const char* name = pnames + shdr.get_sh_name();
1770 this->deferred_layout_relocs_.push_back(
1771 Deferred_layout(i, name, pshdr, 0, elfcpp::SHT_NULL));
1772 out_sections[i] = reinterpret_cast<Output_section*>(2);
1773 out_section_offsets[i] = invalid_address;
1776 if (data_section == NULL)
1778 out_sections[i] = NULL;
1779 out_section_offsets[i] = invalid_address;
1783 Relocatable_relocs* rr = new Relocatable_relocs();
1784 this->set_relocatable_relocs(i, rr);
1786 Output_section* os = layout->layout_reloc(this, i, shdr, data_section,
1788 out_sections[i] = os;
1789 out_section_offsets[i] = invalid_address;
1792 // When building a .gdb_index section, scan the .debug_info and
1793 // .debug_types sections.
1794 gold_assert(!is_pass_one
1795 || (debug_info_sections.empty() && debug_types_sections.empty()));
1796 for (std::vector<unsigned int>::const_iterator p
1797 = debug_info_sections.begin();
1798 p != debug_info_sections.end();
1801 unsigned int i = *p;
1802 layout->add_to_gdb_index(false, this, symbols_data, symbols_size,
1803 i, reloc_shndx[i], reloc_type[i]);
1805 for (std::vector<unsigned int>::const_iterator p
1806 = debug_types_sections.begin();
1807 p != debug_types_sections.end();
1810 unsigned int i = *p;
1811 layout->add_to_gdb_index(true, this, symbols_data, symbols_size,
1812 i, reloc_shndx[i], reloc_type[i]);
1817 delete[] gc_sd->section_headers_data;
1818 delete[] gc_sd->section_names_data;
1819 delete[] gc_sd->symbols_data;
1820 delete[] gc_sd->symbol_names_data;
1821 this->set_symbols_data(NULL);
1825 delete sd->section_headers;
1826 sd->section_headers = NULL;
1827 delete sd->section_names;
1828 sd->section_names = NULL;
1832 // Layout sections whose layout was deferred while waiting for
1833 // input files from a plugin.
1835 template<int size, bool big_endian>
1837 Sized_relobj_file<size, big_endian>::do_layout_deferred_sections(Layout* layout)
1839 typename std::vector<Deferred_layout>::iterator deferred;
1841 for (deferred = this->deferred_layout_.begin();
1842 deferred != this->deferred_layout_.end();
1845 typename This::Shdr shdr(deferred->shdr_data_);
1847 if (!parameters->options().relocatable()
1848 && deferred->name_ == ".eh_frame"
1849 && this->check_eh_frame_flags(&shdr))
1851 // Checking is_section_included is not reliable for
1852 // .eh_frame sections, because they do not have an output
1853 // section. This is not a problem normally because we call
1854 // layout_eh_frame_section unconditionally, but when
1855 // deferring sections that is not true. We don't want to
1856 // keep all .eh_frame sections because that will cause us to
1857 // keep all sections that they refer to, which is the wrong
1858 // way around. Instead, the eh_frame code will discard
1859 // .eh_frame sections that refer to discarded sections.
1861 // Reading the symbols again here may be slow.
1862 Read_symbols_data sd;
1863 this->base_read_symbols(&sd);
1864 this->layout_eh_frame_section(layout,
1867 sd.symbol_names->data(),
1868 sd.symbol_names_size,
1871 deferred->reloc_shndx_,
1872 deferred->reloc_type_);
1876 // If the section is not included, it is because the garbage collector
1877 // decided it is not needed. Avoid reverting that decision.
1878 if (!this->is_section_included(deferred->shndx_))
1881 this->layout_section(layout, deferred->shndx_, deferred->name_.c_str(),
1882 shdr, deferred->reloc_shndx_,
1883 deferred->reloc_type_);
1886 this->deferred_layout_.clear();
1888 // Now handle the deferred relocation sections.
1890 Output_sections& out_sections(this->output_sections());
1891 std::vector<Address>& out_section_offsets(this->section_offsets());
1893 for (deferred = this->deferred_layout_relocs_.begin();
1894 deferred != this->deferred_layout_relocs_.end();
1897 unsigned int shndx = deferred->shndx_;
1898 typename This::Shdr shdr(deferred->shdr_data_);
1899 unsigned int data_shndx = this->adjust_shndx(shdr.get_sh_info());
1901 Output_section* data_section = out_sections[data_shndx];
1902 if (data_section == NULL)
1904 out_sections[shndx] = NULL;
1905 out_section_offsets[shndx] = invalid_address;
1909 Relocatable_relocs* rr = new Relocatable_relocs();
1910 this->set_relocatable_relocs(shndx, rr);
1912 Output_section* os = layout->layout_reloc(this, shndx, shdr,
1914 out_sections[shndx] = os;
1915 out_section_offsets[shndx] = invalid_address;
1919 // Add the symbols to the symbol table.
1921 template<int size, bool big_endian>
1923 Sized_relobj_file<size, big_endian>::do_add_symbols(Symbol_table* symtab,
1924 Read_symbols_data* sd,
1927 if (sd->symbols == NULL)
1929 gold_assert(sd->symbol_names == NULL);
1933 const int sym_size = This::sym_size;
1934 size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1936 if (symcount * sym_size != sd->symbols_size - sd->external_symbols_offset)
1938 this->error(_("size of symbols is not multiple of symbol size"));
1942 this->symbols_.resize(symcount);
1944 const char* sym_names =
1945 reinterpret_cast<const char*>(sd->symbol_names->data());
1946 symtab->add_from_relobj(this,
1947 sd->symbols->data() + sd->external_symbols_offset,
1948 symcount, this->local_symbol_count_,
1949 sym_names, sd->symbol_names_size,
1951 &this->defined_count_);
1955 delete sd->symbol_names;
1956 sd->symbol_names = NULL;
1959 // Find out if this object, that is a member of a lib group, should be included
1960 // in the link. We check every symbol defined by this object. If the symbol
1961 // table has a strong undefined reference to that symbol, we have to include
1964 template<int size, bool big_endian>
1965 Archive::Should_include
1966 Sized_relobj_file<size, big_endian>::do_should_include_member(
1967 Symbol_table* symtab,
1969 Read_symbols_data* sd,
1972 char* tmpbuf = NULL;
1973 size_t tmpbuflen = 0;
1974 const char* sym_names =
1975 reinterpret_cast<const char*>(sd->symbol_names->data());
1976 const unsigned char* syms =
1977 sd->symbols->data() + sd->external_symbols_offset;
1978 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
1979 size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
1982 const unsigned char* p = syms;
1984 for (size_t i = 0; i < symcount; ++i, p += sym_size)
1986 elfcpp::Sym<size, big_endian> sym(p);
1987 unsigned int st_shndx = sym.get_st_shndx();
1988 if (st_shndx == elfcpp::SHN_UNDEF)
1991 unsigned int st_name = sym.get_st_name();
1992 const char* name = sym_names + st_name;
1994 Archive::Should_include t = Archive::should_include_member(symtab,
2000 if (t == Archive::SHOULD_INCLUDE_YES)
2009 return Archive::SHOULD_INCLUDE_UNKNOWN;
2012 // Iterate over global defined symbols, calling a visitor class V for each.
2014 template<int size, bool big_endian>
2016 Sized_relobj_file<size, big_endian>::do_for_all_global_symbols(
2017 Read_symbols_data* sd,
2018 Library_base::Symbol_visitor_base* v)
2020 const char* sym_names =
2021 reinterpret_cast<const char*>(sd->symbol_names->data());
2022 const unsigned char* syms =
2023 sd->symbols->data() + sd->external_symbols_offset;
2024 const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
2025 size_t symcount = ((sd->symbols_size - sd->external_symbols_offset)
2027 const unsigned char* p = syms;
2029 for (size_t i = 0; i < symcount; ++i, p += sym_size)
2031 elfcpp::Sym<size, big_endian> sym(p);
2032 if (sym.get_st_shndx() != elfcpp::SHN_UNDEF)
2033 v->visit(sym_names + sym.get_st_name());
2037 // Return whether the local symbol SYMNDX has a PLT offset.
2039 template<int size, bool big_endian>
2041 Sized_relobj_file<size, big_endian>::local_has_plt_offset(
2042 unsigned int symndx) const
2044 typename Local_plt_offsets::const_iterator p =
2045 this->local_plt_offsets_.find(symndx);
2046 return p != this->local_plt_offsets_.end();
2049 // Get the PLT offset of a local symbol.
2051 template<int size, bool big_endian>
2053 Sized_relobj_file<size, big_endian>::do_local_plt_offset(
2054 unsigned int symndx) const
2056 typename Local_plt_offsets::const_iterator p =
2057 this->local_plt_offsets_.find(symndx);
2058 gold_assert(p != this->local_plt_offsets_.end());
2062 // Set the PLT offset of a local symbol.
2064 template<int size, bool big_endian>
2066 Sized_relobj_file<size, big_endian>::set_local_plt_offset(
2067 unsigned int symndx, unsigned int plt_offset)
2069 std::pair<typename Local_plt_offsets::iterator, bool> ins =
2070 this->local_plt_offsets_.insert(std::make_pair(symndx, plt_offset));
2071 gold_assert(ins.second);
2074 // First pass over the local symbols. Here we add their names to
2075 // *POOL and *DYNPOOL, and we store the symbol value in
2076 // THIS->LOCAL_VALUES_. This function is always called from a
2077 // singleton thread. This is followed by a call to
2078 // finalize_local_symbols.
2080 template<int size, bool big_endian>
2082 Sized_relobj_file<size, big_endian>::do_count_local_symbols(Stringpool* pool,
2083 Stringpool* dynpool)
2085 gold_assert(this->symtab_shndx_ != -1U);
2086 if (this->symtab_shndx_ == 0)
2088 // This object has no symbols. Weird but legal.
2092 // Read the symbol table section header.
2093 const unsigned int symtab_shndx = this->symtab_shndx_;
2094 typename This::Shdr symtabshdr(this,
2095 this->elf_file_.section_header(symtab_shndx));
2096 gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
2098 // Read the local symbols.
2099 const int sym_size = This::sym_size;
2100 const unsigned int loccount = this->local_symbol_count_;
2101 gold_assert(loccount == symtabshdr.get_sh_info());
2102 off_t locsize = loccount * sym_size;
2103 const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
2104 locsize, true, true);
2106 // Read the symbol names.
2107 const unsigned int strtab_shndx =
2108 this->adjust_shndx(symtabshdr.get_sh_link());
2109 section_size_type strtab_size;
2110 const unsigned char* pnamesu = this->section_contents(strtab_shndx,
2113 const char* pnames = reinterpret_cast<const char*>(pnamesu);
2115 // Loop over the local symbols.
2117 const Output_sections& out_sections(this->output_sections());
2118 unsigned int shnum = this->shnum();
2119 unsigned int count = 0;
2120 unsigned int dyncount = 0;
2121 // Skip the first, dummy, symbol.
2123 bool strip_all = parameters->options().strip_all();
2124 bool discard_all = parameters->options().discard_all();
2125 bool discard_locals = parameters->options().discard_locals();
2126 for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
2128 elfcpp::Sym<size, big_endian> sym(psyms);
2130 Symbol_value<size>& lv(this->local_values_[i]);
2133 unsigned int shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
2135 lv.set_input_shndx(shndx, is_ordinary);
2137 if (sym.get_st_type() == elfcpp::STT_SECTION)
2138 lv.set_is_section_symbol();
2139 else if (sym.get_st_type() == elfcpp::STT_TLS)
2140 lv.set_is_tls_symbol();
2141 else if (sym.get_st_type() == elfcpp::STT_GNU_IFUNC)
2142 lv.set_is_ifunc_symbol();
2144 // Save the input symbol value for use in do_finalize_local_symbols().
2145 lv.set_input_value(sym.get_st_value());
2147 // Decide whether this symbol should go into the output file.
2149 if ((shndx < shnum && out_sections[shndx] == NULL)
2150 || shndx == this->discarded_eh_frame_shndx_)
2152 lv.set_no_output_symtab_entry();
2153 gold_assert(!lv.needs_output_dynsym_entry());
2157 if (sym.get_st_type() == elfcpp::STT_SECTION
2158 || !this->adjust_local_symbol(&lv))
2160 lv.set_no_output_symtab_entry();
2161 gold_assert(!lv.needs_output_dynsym_entry());
2165 if (sym.get_st_name() >= strtab_size)
2167 this->error(_("local symbol %u section name out of range: %u >= %u"),
2168 i, sym.get_st_name(),
2169 static_cast<unsigned int>(strtab_size));
2170 lv.set_no_output_symtab_entry();
2174 const char* name = pnames + sym.get_st_name();
2176 // If needed, add the symbol to the dynamic symbol table string pool.
2177 if (lv.needs_output_dynsym_entry())
2179 dynpool->add(name, true, NULL);
2184 || (discard_all && lv.may_be_discarded_from_output_symtab()))
2186 lv.set_no_output_symtab_entry();
2190 // If --discard-locals option is used, discard all temporary local
2191 // symbols. These symbols start with system-specific local label
2192 // prefixes, typically .L for ELF system. We want to be compatible
2193 // with GNU ld so here we essentially use the same check in
2194 // bfd_is_local_label(). The code is different because we already
2197 // - the symbol is local and thus cannot have global or weak binding.
2198 // - the symbol is not a section symbol.
2199 // - the symbol has a name.
2201 // We do not discard a symbol if it needs a dynamic symbol entry.
2203 && sym.get_st_type() != elfcpp::STT_FILE
2204 && !lv.needs_output_dynsym_entry()
2205 && lv.may_be_discarded_from_output_symtab()
2206 && parameters->target().is_local_label_name(name))
2208 lv.set_no_output_symtab_entry();
2212 // Discard the local symbol if -retain_symbols_file is specified
2213 // and the local symbol is not in that file.
2214 if (!parameters->options().should_retain_symbol(name))
2216 lv.set_no_output_symtab_entry();
2220 // Add the symbol to the symbol table string pool.
2221 pool->add(name, true, NULL);
2225 this->output_local_symbol_count_ = count;
2226 this->output_local_dynsym_count_ = dyncount;
2229 // Compute the final value of a local symbol.
2231 template<int size, bool big_endian>
2232 typename Sized_relobj_file<size, big_endian>::Compute_final_local_value_status
2233 Sized_relobj_file<size, big_endian>::compute_final_local_value_internal(
2235 const Symbol_value<size>* lv_in,
2236 Symbol_value<size>* lv_out,
2238 const Output_sections& out_sections,
2239 const std::vector<Address>& out_offsets,
2240 const Symbol_table* symtab)
2242 // We are going to overwrite *LV_OUT, if it has a merged symbol value,
2243 // we may have a memory leak.
2244 gold_assert(lv_out->has_output_value());
2247 unsigned int shndx = lv_in->input_shndx(&is_ordinary);
2249 // Set the output symbol value.
2253 if (shndx == elfcpp::SHN_ABS || Symbol::is_common_shndx(shndx))
2254 lv_out->set_output_value(lv_in->input_value());
2257 this->error(_("unknown section index %u for local symbol %u"),
2259 lv_out->set_output_value(0);
2260 return This::CFLV_ERROR;
2265 if (shndx >= this->shnum())
2267 this->error(_("local symbol %u section index %u out of range"),
2269 lv_out->set_output_value(0);
2270 return This::CFLV_ERROR;
2273 Output_section* os = out_sections[shndx];
2274 Address secoffset = out_offsets[shndx];
2275 if (symtab->is_section_folded(this, shndx))
2277 gold_assert(os == NULL && secoffset == invalid_address);
2278 // Get the os of the section it is folded onto.
2279 Section_id folded = symtab->icf()->get_folded_section(this,
2281 gold_assert(folded.first != NULL);
2282 Sized_relobj_file<size, big_endian>* folded_obj = reinterpret_cast
2283 <Sized_relobj_file<size, big_endian>*>(folded.first);
2284 os = folded_obj->output_section(folded.second);
2285 gold_assert(os != NULL);
2286 secoffset = folded_obj->get_output_section_offset(folded.second);
2288 // This could be a relaxed input section.
2289 if (secoffset == invalid_address)
2291 const Output_relaxed_input_section* relaxed_section =
2292 os->find_relaxed_input_section(folded_obj, folded.second);
2293 gold_assert(relaxed_section != NULL);
2294 secoffset = relaxed_section->address() - os->address();
2300 // This local symbol belongs to a section we are discarding.
2301 // In some cases when applying relocations later, we will
2302 // attempt to match it to the corresponding kept section,
2303 // so we leave the input value unchanged here.
2304 return This::CFLV_DISCARDED;
2306 else if (secoffset == invalid_address)
2310 // This is a SHF_MERGE section or one which otherwise
2311 // requires special handling.
2312 if (shndx == this->discarded_eh_frame_shndx_)
2314 // This local symbol belongs to a discarded .eh_frame
2315 // section. Just treat it like the case in which
2316 // os == NULL above.
2317 gold_assert(this->has_eh_frame_);
2318 return This::CFLV_DISCARDED;
2320 else if (!lv_in->is_section_symbol())
2322 // This is not a section symbol. We can determine
2323 // the final value now.
2324 lv_out->set_output_value(
2325 os->output_address(this, shndx, lv_in->input_value()));
2327 else if (!os->find_starting_output_address(this, shndx, &start))
2329 // This is a section symbol, but apparently not one in a
2330 // merged section. First check to see if this is a relaxed
2331 // input section. If so, use its address. Otherwise just
2332 // use the start of the output section. This happens with
2333 // relocatable links when the input object has section
2334 // symbols for arbitrary non-merge sections.
2335 const Output_section_data* posd =
2336 os->find_relaxed_input_section(this, shndx);
2339 Address relocatable_link_adjustment =
2340 relocatable ? os->address() : 0;
2341 lv_out->set_output_value(posd->address()
2342 - relocatable_link_adjustment);
2345 lv_out->set_output_value(os->address());
2349 // We have to consider the addend to determine the
2350 // value to use in a relocation. START is the start
2351 // of this input section. If we are doing a relocatable
2352 // link, use offset from start output section instead of
2354 Address adjusted_start =
2355 relocatable ? start - os->address() : start;
2356 Merged_symbol_value<size>* msv =
2357 new Merged_symbol_value<size>(lv_in->input_value(),
2359 lv_out->set_merged_symbol_value(msv);
2362 else if (lv_in->is_tls_symbol()
2363 || (lv_in->is_section_symbol()
2364 && (os->flags() & elfcpp::SHF_TLS)))
2365 lv_out->set_output_value(os->tls_offset()
2367 + lv_in->input_value());
2369 lv_out->set_output_value((relocatable ? 0 : os->address())
2371 + lv_in->input_value());
2373 return This::CFLV_OK;
2376 // Compute final local symbol value. R_SYM is the index of a local
2377 // symbol in symbol table. LV points to a symbol value, which is
2378 // expected to hold the input value and to be over-written by the
2379 // final value. SYMTAB points to a symbol table. Some targets may want
2380 // to know would-be-finalized local symbol values in relaxation.
2381 // Hence we provide this method. Since this method updates *LV, a
2382 // callee should make a copy of the original local symbol value and
2383 // use the copy instead of modifying an object's local symbols before
2384 // everything is finalized. The caller should also free up any allocated
2385 // memory in the return value in *LV.
2386 template<int size, bool big_endian>
2387 typename Sized_relobj_file<size, big_endian>::Compute_final_local_value_status
2388 Sized_relobj_file<size, big_endian>::compute_final_local_value(
2390 const Symbol_value<size>* lv_in,
2391 Symbol_value<size>* lv_out,
2392 const Symbol_table* symtab)
2394 // This is just a wrapper of compute_final_local_value_internal.
2395 const bool relocatable = parameters->options().relocatable();
2396 const Output_sections& out_sections(this->output_sections());
2397 const std::vector<Address>& out_offsets(this->section_offsets());
2398 return this->compute_final_local_value_internal(r_sym, lv_in, lv_out,
2399 relocatable, out_sections,
2400 out_offsets, symtab);
2403 // Finalize the local symbols. Here we set the final value in
2404 // THIS->LOCAL_VALUES_ and set their output symbol table indexes.
2405 // This function is always called from a singleton thread. The actual
2406 // output of the local symbols will occur in a separate task.
2408 template<int size, bool big_endian>
2410 Sized_relobj_file<size, big_endian>::do_finalize_local_symbols(
2413 Symbol_table* symtab)
2415 gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
2417 const unsigned int loccount = this->local_symbol_count_;
2418 this->local_symbol_offset_ = off;
2420 const bool relocatable = parameters->options().relocatable();
2421 const Output_sections& out_sections(this->output_sections());
2422 const std::vector<Address>& out_offsets(this->section_offsets());
2424 for (unsigned int i = 1; i < loccount; ++i)
2426 Symbol_value<size>* lv = &this->local_values_[i];
2428 Compute_final_local_value_status cflv_status =
2429 this->compute_final_local_value_internal(i, lv, lv, relocatable,
2430 out_sections, out_offsets,
2432 switch (cflv_status)
2435 if (!lv->is_output_symtab_index_set())
2437 lv->set_output_symtab_index(index);
2441 case CFLV_DISCARDED:
2452 // Set the output dynamic symbol table indexes for the local variables.
2454 template<int size, bool big_endian>
2456 Sized_relobj_file<size, big_endian>::do_set_local_dynsym_indexes(
2459 const unsigned int loccount = this->local_symbol_count_;
2460 for (unsigned int i = 1; i < loccount; ++i)
2462 Symbol_value<size>& lv(this->local_values_[i]);
2463 if (lv.needs_output_dynsym_entry())
2465 lv.set_output_dynsym_index(index);
2472 // Set the offset where local dynamic symbol information will be stored.
2473 // Returns the count of local symbols contributed to the symbol table by
2476 template<int size, bool big_endian>
2478 Sized_relobj_file<size, big_endian>::do_set_local_dynsym_offset(off_t off)
2480 gold_assert(off == static_cast<off_t>(align_address(off, size >> 3)));
2481 this->local_dynsym_offset_ = off;
2482 return this->output_local_dynsym_count_;
2485 // If Symbols_data is not NULL get the section flags from here otherwise
2486 // get it from the file.
2488 template<int size, bool big_endian>
2490 Sized_relobj_file<size, big_endian>::do_section_flags(unsigned int shndx)
2492 Symbols_data* sd = this->get_symbols_data();
2495 const unsigned char* pshdrs = sd->section_headers_data
2496 + This::shdr_size * shndx;
2497 typename This::Shdr shdr(pshdrs);
2498 return shdr.get_sh_flags();
2500 // If sd is NULL, read the section header from the file.
2501 return this->elf_file_.section_flags(shndx);
2504 // Get the section's ent size from Symbols_data. Called by get_section_contents
2507 template<int size, bool big_endian>
2509 Sized_relobj_file<size, big_endian>::do_section_entsize(unsigned int shndx)
2511 Symbols_data* sd = this->get_symbols_data();
2512 gold_assert(sd != NULL);
2514 const unsigned char* pshdrs = sd->section_headers_data
2515 + This::shdr_size * shndx;
2516 typename This::Shdr shdr(pshdrs);
2517 return shdr.get_sh_entsize();
2520 // Write out the local symbols.
2522 template<int size, bool big_endian>
2524 Sized_relobj_file<size, big_endian>::write_local_symbols(
2526 const Stringpool* sympool,
2527 const Stringpool* dynpool,
2528 Output_symtab_xindex* symtab_xindex,
2529 Output_symtab_xindex* dynsym_xindex,
2532 const bool strip_all = parameters->options().strip_all();
2535 if (this->output_local_dynsym_count_ == 0)
2537 this->output_local_symbol_count_ = 0;
2540 gold_assert(this->symtab_shndx_ != -1U);
2541 if (this->symtab_shndx_ == 0)
2543 // This object has no symbols. Weird but legal.
2547 // Read the symbol table section header.
2548 const unsigned int symtab_shndx = this->symtab_shndx_;
2549 typename This::Shdr symtabshdr(this,
2550 this->elf_file_.section_header(symtab_shndx));
2551 gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
2552 const unsigned int loccount = this->local_symbol_count_;
2553 gold_assert(loccount == symtabshdr.get_sh_info());
2555 // Read the local symbols.
2556 const int sym_size = This::sym_size;
2557 off_t locsize = loccount * sym_size;
2558 const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
2559 locsize, true, false);
2561 // Read the symbol names.
2562 const unsigned int strtab_shndx =
2563 this->adjust_shndx(symtabshdr.get_sh_link());
2564 section_size_type strtab_size;
2565 const unsigned char* pnamesu = this->section_contents(strtab_shndx,
2568 const char* pnames = reinterpret_cast<const char*>(pnamesu);
2570 // Get views into the output file for the portions of the symbol table
2571 // and the dynamic symbol table that we will be writing.
2572 off_t output_size = this->output_local_symbol_count_ * sym_size;
2573 unsigned char* oview = NULL;
2574 if (output_size > 0)
2575 oview = of->get_output_view(symtab_off + this->local_symbol_offset_,
2578 off_t dyn_output_size = this->output_local_dynsym_count_ * sym_size;
2579 unsigned char* dyn_oview = NULL;
2580 if (dyn_output_size > 0)
2581 dyn_oview = of->get_output_view(this->local_dynsym_offset_,
2584 const Output_sections out_sections(this->output_sections());
2586 gold_assert(this->local_values_.size() == loccount);
2588 unsigned char* ov = oview;
2589 unsigned char* dyn_ov = dyn_oview;
2591 for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
2593 elfcpp::Sym<size, big_endian> isym(psyms);
2595 Symbol_value<size>& lv(this->local_values_[i]);
2598 unsigned int st_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
2602 gold_assert(st_shndx < out_sections.size());
2603 if (out_sections[st_shndx] == NULL)
2605 st_shndx = out_sections[st_shndx]->out_shndx();
2606 if (st_shndx >= elfcpp::SHN_LORESERVE)
2608 if (lv.has_output_symtab_entry())
2609 symtab_xindex->add(lv.output_symtab_index(), st_shndx);
2610 if (lv.has_output_dynsym_entry())
2611 dynsym_xindex->add(lv.output_dynsym_index(), st_shndx);
2612 st_shndx = elfcpp::SHN_XINDEX;
2616 // Write the symbol to the output symbol table.
2617 if (lv.has_output_symtab_entry())
2619 elfcpp::Sym_write<size, big_endian> osym(ov);
2621 gold_assert(isym.get_st_name() < strtab_size);
2622 const char* name = pnames + isym.get_st_name();
2623 osym.put_st_name(sympool->get_offset(name));
2624 osym.put_st_value(this->local_values_[i].value(this, 0));
2625 osym.put_st_size(isym.get_st_size());
2626 osym.put_st_info(isym.get_st_info());
2627 osym.put_st_other(isym.get_st_other());
2628 osym.put_st_shndx(st_shndx);
2633 // Write the symbol to the output dynamic symbol table.
2634 if (lv.has_output_dynsym_entry())
2636 gold_assert(dyn_ov < dyn_oview + dyn_output_size);
2637 elfcpp::Sym_write<size, big_endian> osym(dyn_ov);
2639 gold_assert(isym.get_st_name() < strtab_size);
2640 const char* name = pnames + isym.get_st_name();
2641 osym.put_st_name(dynpool->get_offset(name));
2642 osym.put_st_value(this->local_values_[i].value(this, 0));
2643 osym.put_st_size(isym.get_st_size());
2644 osym.put_st_info(isym.get_st_info());
2645 osym.put_st_other(isym.get_st_other());
2646 osym.put_st_shndx(st_shndx);
2653 if (output_size > 0)
2655 gold_assert(ov - oview == output_size);
2656 of->write_output_view(symtab_off + this->local_symbol_offset_,
2657 output_size, oview);
2660 if (dyn_output_size > 0)
2662 gold_assert(dyn_ov - dyn_oview == dyn_output_size);
2663 of->write_output_view(this->local_dynsym_offset_, dyn_output_size,
2668 // Set *INFO to symbolic information about the offset OFFSET in the
2669 // section SHNDX. Return true if we found something, false if we
2672 template<int size, bool big_endian>
2674 Sized_relobj_file<size, big_endian>::get_symbol_location_info(
2677 Symbol_location_info* info)
2679 if (this->symtab_shndx_ == 0)
2682 section_size_type symbols_size;
2683 const unsigned char* symbols = this->section_contents(this->symtab_shndx_,
2687 unsigned int symbol_names_shndx =
2688 this->adjust_shndx(this->section_link(this->symtab_shndx_));
2689 section_size_type names_size;
2690 const unsigned char* symbol_names_u =
2691 this->section_contents(symbol_names_shndx, &names_size, false);
2692 const char* symbol_names = reinterpret_cast<const char*>(symbol_names_u);
2694 const int sym_size = This::sym_size;
2695 const size_t count = symbols_size / sym_size;
2697 const unsigned char* p = symbols;
2698 for (size_t i = 0; i < count; ++i, p += sym_size)
2700 elfcpp::Sym<size, big_endian> sym(p);
2702 if (sym.get_st_type() == elfcpp::STT_FILE)
2704 if (sym.get_st_name() >= names_size)
2705 info->source_file = "(invalid)";
2707 info->source_file = symbol_names + sym.get_st_name();
2712 unsigned int st_shndx = this->adjust_sym_shndx(i, sym.get_st_shndx(),
2715 && st_shndx == shndx
2716 && static_cast<off_t>(sym.get_st_value()) <= offset
2717 && (static_cast<off_t>(sym.get_st_value() + sym.get_st_size())
2720 info->enclosing_symbol_type = sym.get_st_type();
2721 if (sym.get_st_name() > names_size)
2722 info->enclosing_symbol_name = "(invalid)";
2725 info->enclosing_symbol_name = symbol_names + sym.get_st_name();
2726 if (parameters->options().do_demangle())
2728 char* demangled_name = cplus_demangle(
2729 info->enclosing_symbol_name.c_str(),
2730 DMGL_ANSI | DMGL_PARAMS);
2731 if (demangled_name != NULL)
2733 info->enclosing_symbol_name.assign(demangled_name);
2734 free(demangled_name);
2745 // Look for a kept section corresponding to the given discarded section,
2746 // and return its output address. This is used only for relocations in
2747 // debugging sections. If we can't find the kept section, return 0.
2749 template<int size, bool big_endian>
2750 typename Sized_relobj_file<size, big_endian>::Address
2751 Sized_relobj_file<size, big_endian>::map_to_kept_section(
2755 Relobj* kept_object;
2756 unsigned int kept_shndx;
2757 if (this->get_kept_comdat_section(shndx, &kept_object, &kept_shndx))
2759 Sized_relobj_file<size, big_endian>* kept_relobj =
2760 static_cast<Sized_relobj_file<size, big_endian>*>(kept_object);
2761 Output_section* os = kept_relobj->output_section(kept_shndx);
2762 Address offset = kept_relobj->get_output_section_offset(kept_shndx);
2763 if (os != NULL && offset != invalid_address)
2766 return os->address() + offset;
2773 // Get symbol counts.
2775 template<int size, bool big_endian>
2777 Sized_relobj_file<size, big_endian>::do_get_global_symbol_counts(
2778 const Symbol_table*,
2782 *defined = this->defined_count_;
2784 for (typename Symbols::const_iterator p = this->symbols_.begin();
2785 p != this->symbols_.end();
2788 && (*p)->source() == Symbol::FROM_OBJECT
2789 && (*p)->object() == this
2790 && (*p)->is_defined())
2795 // Return a view of the decompressed contents of a section. Set *PLEN
2796 // to the size. Set *IS_NEW to true if the contents need to be freed
2799 template<int size, bool big_endian>
2800 const unsigned char*
2801 Sized_relobj_file<size, big_endian>::do_decompressed_section_contents(
2803 section_size_type* plen,
2806 section_size_type buffer_size;
2807 const unsigned char* buffer = this->do_section_contents(shndx, &buffer_size,
2810 if (this->compressed_sections_ == NULL)
2812 *plen = buffer_size;
2817 Compressed_section_map::const_iterator p =
2818 this->compressed_sections_->find(shndx);
2819 if (p == this->compressed_sections_->end())
2821 *plen = buffer_size;
2826 section_size_type uncompressed_size = p->second.size;
2827 if (p->second.contents != NULL)
2829 *plen = uncompressed_size;
2831 return p->second.contents;
2834 unsigned char* uncompressed_data = new unsigned char[uncompressed_size];
2835 if (!decompress_input_section(buffer,
2839 this->error(_("could not decompress section %s"),
2840 this->do_section_name(shndx).c_str());
2842 // We could cache the results in p->second.contents and store
2843 // false in *IS_NEW, but build_compressed_section_map() would
2844 // have done so if it had expected it to be profitable. If
2845 // we reach this point, we expect to need the contents only
2846 // once in this pass.
2847 *plen = uncompressed_size;
2849 return uncompressed_data;
2852 // Discard any buffers of uncompressed sections. This is done
2853 // at the end of the Add_symbols task.
2855 template<int size, bool big_endian>
2857 Sized_relobj_file<size, big_endian>::do_discard_decompressed_sections()
2859 if (this->compressed_sections_ == NULL)
2862 for (Compressed_section_map::iterator p = this->compressed_sections_->begin();
2863 p != this->compressed_sections_->end();
2866 if (p->second.contents != NULL)
2868 delete[] p->second.contents;
2869 p->second.contents = NULL;
2874 // Input_objects methods.
2876 // Add a regular relocatable object to the list. Return false if this
2877 // object should be ignored.
2880 Input_objects::add_object(Object* obj)
2882 // Print the filename if the -t/--trace option is selected.
2883 if (parameters->options().trace())
2884 gold_info("%s", obj->name().c_str());
2886 if (!obj->is_dynamic())
2887 this->relobj_list_.push_back(static_cast<Relobj*>(obj));
2890 // See if this is a duplicate SONAME.
2891 Dynobj* dynobj = static_cast<Dynobj*>(obj);
2892 const char* soname = dynobj->soname();
2894 std::pair<Unordered_set<std::string>::iterator, bool> ins =
2895 this->sonames_.insert(soname);
2898 // We have already seen a dynamic object with this soname.
2902 this->dynobj_list_.push_back(dynobj);
2905 // Add this object to the cross-referencer if requested.
2906 if (parameters->options().user_set_print_symbol_counts()
2907 || parameters->options().cref())
2909 if (this->cref_ == NULL)
2910 this->cref_ = new Cref();
2911 this->cref_->add_object(obj);
2917 // For each dynamic object, record whether we've seen all of its
2918 // explicit dependencies.
2921 Input_objects::check_dynamic_dependencies() const
2923 bool issued_copy_dt_needed_error = false;
2924 for (Dynobj_list::const_iterator p = this->dynobj_list_.begin();
2925 p != this->dynobj_list_.end();
2928 const Dynobj::Needed& needed((*p)->needed());
2929 bool found_all = true;
2930 Dynobj::Needed::const_iterator pneeded;
2931 for (pneeded = needed.begin(); pneeded != needed.end(); ++pneeded)
2933 if (this->sonames_.find(*pneeded) == this->sonames_.end())
2939 (*p)->set_has_unknown_needed_entries(!found_all);
2941 // --copy-dt-needed-entries aka --add-needed is a GNU ld option
2942 // that gold does not support. However, they cause no trouble
2943 // unless there is a DT_NEEDED entry that we don't know about;
2944 // warn only in that case.
2946 && !issued_copy_dt_needed_error
2947 && (parameters->options().copy_dt_needed_entries()
2948 || parameters->options().add_needed()))
2950 const char* optname;
2951 if (parameters->options().copy_dt_needed_entries())
2952 optname = "--copy-dt-needed-entries";
2954 optname = "--add-needed";
2955 gold_error(_("%s is not supported but is required for %s in %s"),
2956 optname, (*pneeded).c_str(), (*p)->name().c_str());
2957 issued_copy_dt_needed_error = true;
2962 // Start processing an archive.
2965 Input_objects::archive_start(Archive* archive)
2967 if (parameters->options().user_set_print_symbol_counts()
2968 || parameters->options().cref())
2970 if (this->cref_ == NULL)
2971 this->cref_ = new Cref();
2972 this->cref_->add_archive_start(archive);
2976 // Stop processing an archive.
2979 Input_objects::archive_stop(Archive* archive)
2981 if (parameters->options().user_set_print_symbol_counts()
2982 || parameters->options().cref())
2983 this->cref_->add_archive_stop(archive);
2986 // Print symbol counts
2989 Input_objects::print_symbol_counts(const Symbol_table* symtab) const
2991 if (parameters->options().user_set_print_symbol_counts()
2992 && this->cref_ != NULL)
2993 this->cref_->print_symbol_counts(symtab);
2996 // Print a cross reference table.
2999 Input_objects::print_cref(const Symbol_table* symtab, FILE* f) const
3001 if (parameters->options().cref() && this->cref_ != NULL)
3002 this->cref_->print_cref(symtab, f);
3005 // Relocate_info methods.
3007 // Return a string describing the location of a relocation when file
3008 // and lineno information is not available. This is only used in
3011 template<int size, bool big_endian>
3013 Relocate_info<size, big_endian>::location(size_t, off_t offset) const
3015 Sized_dwarf_line_info<size, big_endian> line_info(this->object);
3016 std::string ret = line_info.addr2line(this->data_shndx, offset, NULL);
3020 ret = this->object->name();
3022 Symbol_location_info info;
3023 if (this->object->get_symbol_location_info(this->data_shndx, offset, &info))
3025 if (!info.source_file.empty())
3028 ret += info.source_file;
3031 if (info.enclosing_symbol_type == elfcpp::STT_FUNC)
3032 ret += _("function ");
3033 ret += info.enclosing_symbol_name;
3038 ret += this->object->section_name(this->data_shndx);
3040 snprintf(buf, sizeof buf, "+0x%lx)", static_cast<long>(offset));
3045 } // End namespace gold.
3050 using namespace gold;
3052 // Read an ELF file with the header and return the appropriate
3053 // instance of Object.
3055 template<int size, bool big_endian>
3057 make_elf_sized_object(const std::string& name, Input_file* input_file,
3058 off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr,
3059 bool* punconfigured)
3061 Target* target = select_target(input_file, offset,
3062 ehdr.get_e_machine(), size, big_endian,
3063 ehdr.get_e_ident()[elfcpp::EI_OSABI],
3064 ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
3066 gold_fatal(_("%s: unsupported ELF machine number %d"),
3067 name.c_str(), ehdr.get_e_machine());
3069 if (!parameters->target_valid())
3070 set_parameters_target(target);
3071 else if (target != ¶meters->target())
3073 if (punconfigured != NULL)
3074 *punconfigured = true;
3076 gold_error(_("%s: incompatible target"), name.c_str());
3080 return target->make_elf_object<size, big_endian>(name, input_file, offset,
3084 } // End anonymous namespace.
3089 // Return whether INPUT_FILE is an ELF object.
3092 is_elf_object(Input_file* input_file, off_t offset,
3093 const unsigned char** start, int* read_size)
3095 off_t filesize = input_file->file().filesize();
3096 int want = elfcpp::Elf_recognizer::max_header_size;
3097 if (filesize - offset < want)
3098 want = filesize - offset;
3100 const unsigned char* p = input_file->file().get_view(offset, 0, want,
3105 return elfcpp::Elf_recognizer::is_elf_file(p, want);
3108 // Read an ELF file and return the appropriate instance of Object.
3111 make_elf_object(const std::string& name, Input_file* input_file, off_t offset,
3112 const unsigned char* p, section_offset_type bytes,
3113 bool* punconfigured)
3115 if (punconfigured != NULL)
3116 *punconfigured = false;
3119 bool big_endian = false;
3121 if (!elfcpp::Elf_recognizer::is_valid_header(p, bytes, &size,
3122 &big_endian, &error))
3124 gold_error(_("%s: %s"), name.c_str(), error.c_str());
3132 #ifdef HAVE_TARGET_32_BIG
3133 elfcpp::Ehdr<32, true> ehdr(p);
3134 return make_elf_sized_object<32, true>(name, input_file,
3135 offset, ehdr, punconfigured);
3137 if (punconfigured != NULL)
3138 *punconfigured = true;
3140 gold_error(_("%s: not configured to support "
3141 "32-bit big-endian object"),
3148 #ifdef HAVE_TARGET_32_LITTLE
3149 elfcpp::Ehdr<32, false> ehdr(p);
3150 return make_elf_sized_object<32, false>(name, input_file,
3151 offset, ehdr, punconfigured);
3153 if (punconfigured != NULL)
3154 *punconfigured = true;
3156 gold_error(_("%s: not configured to support "
3157 "32-bit little-endian object"),
3163 else if (size == 64)
3167 #ifdef HAVE_TARGET_64_BIG
3168 elfcpp::Ehdr<64, true> ehdr(p);
3169 return make_elf_sized_object<64, true>(name, input_file,
3170 offset, ehdr, punconfigured);
3172 if (punconfigured != NULL)
3173 *punconfigured = true;
3175 gold_error(_("%s: not configured to support "
3176 "64-bit big-endian object"),
3183 #ifdef HAVE_TARGET_64_LITTLE
3184 elfcpp::Ehdr<64, false> ehdr(p);
3185 return make_elf_sized_object<64, false>(name, input_file,
3186 offset, ehdr, punconfigured);
3188 if (punconfigured != NULL)
3189 *punconfigured = true;
3191 gold_error(_("%s: not configured to support "
3192 "64-bit little-endian object"),
3202 // Instantiate the templates we need.
3204 #ifdef HAVE_TARGET_32_LITTLE
3207 Object::read_section_data<32, false>(elfcpp::Elf_file<32, false, Object>*,
3208 Read_symbols_data*);
3210 const unsigned char*
3211 Object::find_shdr<32,false>(const unsigned char*, const char*, const char*,
3212 section_size_type, const unsigned char*) const;
3215 #ifdef HAVE_TARGET_32_BIG
3218 Object::read_section_data<32, true>(elfcpp::Elf_file<32, true, Object>*,
3219 Read_symbols_data*);
3221 const unsigned char*
3222 Object::find_shdr<32,true>(const unsigned char*, const char*, const char*,
3223 section_size_type, const unsigned char*) const;
3226 #ifdef HAVE_TARGET_64_LITTLE
3229 Object::read_section_data<64, false>(elfcpp::Elf_file<64, false, Object>*,
3230 Read_symbols_data*);
3232 const unsigned char*
3233 Object::find_shdr<64,false>(const unsigned char*, const char*, const char*,
3234 section_size_type, const unsigned char*) const;
3237 #ifdef HAVE_TARGET_64_BIG
3240 Object::read_section_data<64, true>(elfcpp::Elf_file<64, true, Object>*,
3241 Read_symbols_data*);
3243 const unsigned char*
3244 Object::find_shdr<64,true>(const unsigned char*, const char*, const char*,
3245 section_size_type, const unsigned char*) const;
3248 #ifdef HAVE_TARGET_32_LITTLE
3250 class Sized_relobj<32, false>;
3253 class Sized_relobj_file<32, false>;
3256 #ifdef HAVE_TARGET_32_BIG
3258 class Sized_relobj<32, true>;
3261 class Sized_relobj_file<32, true>;
3264 #ifdef HAVE_TARGET_64_LITTLE
3266 class Sized_relobj<64, false>;
3269 class Sized_relobj_file<64, false>;
3272 #ifdef HAVE_TARGET_64_BIG
3274 class Sized_relobj<64, true>;
3277 class Sized_relobj_file<64, true>;
3280 #ifdef HAVE_TARGET_32_LITTLE
3282 struct Relocate_info<32, false>;
3285 #ifdef HAVE_TARGET_32_BIG
3287 struct Relocate_info<32, true>;
3290 #ifdef HAVE_TARGET_64_LITTLE
3292 struct Relocate_info<64, false>;
3295 #ifdef HAVE_TARGET_64_BIG
3297 struct Relocate_info<64, true>;
3300 #ifdef HAVE_TARGET_32_LITTLE
3303 Xindex::initialize_symtab_xindex<32, false>(Object*, unsigned int);
3307 Xindex::read_symtab_xindex<32, false>(Object*, unsigned int,
3308 const unsigned char*);
3311 #ifdef HAVE_TARGET_32_BIG
3314 Xindex::initialize_symtab_xindex<32, true>(Object*, unsigned int);
3318 Xindex::read_symtab_xindex<32, true>(Object*, unsigned int,
3319 const unsigned char*);
3322 #ifdef HAVE_TARGET_64_LITTLE
3325 Xindex::initialize_symtab_xindex<64, false>(Object*, unsigned int);
3329 Xindex::read_symtab_xindex<64, false>(Object*, unsigned int,
3330 const unsigned char*);
3333 #ifdef HAVE_TARGET_64_BIG
3336 Xindex::initialize_symtab_xindex<64, true>(Object*, unsigned int);
3340 Xindex::read_symtab_xindex<64, true>(Object*, unsigned int,
3341 const unsigned char*);
3344 } // End namespace gold.