1 // output.cc -- manage the output file for gold
3 // Copyright 2006, 2007 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.
33 #include "parameters.h"
43 // Output_data variables.
45 bool Output_data::sizes_are_fixed;
47 // Output_data methods.
49 Output_data::~Output_data()
53 // Set the address and offset.
56 Output_data::set_address(uint64_t addr, off_t off)
58 this->address_ = addr;
61 // Let the child class know.
62 this->do_set_address(addr, off);
65 // Return the default alignment for a size--32 or 64.
68 Output_data::default_alignment(int size)
78 // Output_section_header methods. This currently assumes that the
79 // segment and section lists are complete at construction time.
81 Output_section_headers::Output_section_headers(
83 const Layout::Segment_list* segment_list,
84 const Layout::Section_list* unattached_section_list,
85 const Stringpool* secnamepool)
87 segment_list_(segment_list),
88 unattached_section_list_(unattached_section_list),
89 secnamepool_(secnamepool)
91 // Count all the sections. Start with 1 for the null section.
93 for (Layout::Segment_list::const_iterator p = segment_list->begin();
94 p != segment_list->end();
96 if ((*p)->type() == elfcpp::PT_LOAD)
97 count += (*p)->output_section_count();
98 count += unattached_section_list->size();
100 const int size = parameters->get_size();
103 shdr_size = elfcpp::Elf_sizes<32>::shdr_size;
105 shdr_size = elfcpp::Elf_sizes<64>::shdr_size;
109 this->set_data_size(count * shdr_size);
112 // Write out the section headers.
115 Output_section_headers::do_write(Output_file* of)
117 if (parameters->get_size() == 32)
119 if (parameters->is_big_endian())
121 #ifdef HAVE_TARGET_32_BIG
122 this->do_sized_write<32, true>(of);
129 #ifdef HAVE_TARGET_32_LITTLE
130 this->do_sized_write<32, false>(of);
136 else if (parameters->get_size() == 64)
138 if (parameters->is_big_endian())
140 #ifdef HAVE_TARGET_64_BIG
141 this->do_sized_write<64, true>(of);
148 #ifdef HAVE_TARGET_64_LITTLE
149 this->do_sized_write<64, false>(of);
159 template<int size, bool big_endian>
161 Output_section_headers::do_sized_write(Output_file* of)
163 off_t all_shdrs_size = this->data_size();
164 unsigned char* view = of->get_output_view(this->offset(), all_shdrs_size);
166 const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
167 unsigned char* v = view;
170 typename elfcpp::Shdr_write<size, big_endian> oshdr(v);
171 oshdr.put_sh_name(0);
172 oshdr.put_sh_type(elfcpp::SHT_NULL);
173 oshdr.put_sh_flags(0);
174 oshdr.put_sh_addr(0);
175 oshdr.put_sh_offset(0);
176 oshdr.put_sh_size(0);
177 oshdr.put_sh_link(0);
178 oshdr.put_sh_info(0);
179 oshdr.put_sh_addralign(0);
180 oshdr.put_sh_entsize(0);
186 for (Layout::Segment_list::const_iterator p = this->segment_list_->begin();
187 p != this->segment_list_->end();
189 v = (*p)->write_section_headers SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
190 this->layout_, this->secnamepool_, v, &shndx
191 SELECT_SIZE_ENDIAN(size, big_endian));
192 for (Layout::Section_list::const_iterator p =
193 this->unattached_section_list_->begin();
194 p != this->unattached_section_list_->end();
197 gold_assert(shndx == (*p)->out_shndx());
198 elfcpp::Shdr_write<size, big_endian> oshdr(v);
199 (*p)->write_header(this->layout_, this->secnamepool_, &oshdr);
204 of->write_output_view(this->offset(), all_shdrs_size, view);
207 // Output_segment_header methods.
209 Output_segment_headers::Output_segment_headers(
210 const Layout::Segment_list& segment_list)
211 : segment_list_(segment_list)
213 const int size = parameters->get_size();
216 phdr_size = elfcpp::Elf_sizes<32>::phdr_size;
218 phdr_size = elfcpp::Elf_sizes<64>::phdr_size;
222 this->set_data_size(segment_list.size() * phdr_size);
226 Output_segment_headers::do_write(Output_file* of)
228 if (parameters->get_size() == 32)
230 if (parameters->is_big_endian())
232 #ifdef HAVE_TARGET_32_BIG
233 this->do_sized_write<32, true>(of);
240 #ifdef HAVE_TARGET_32_LITTLE
241 this->do_sized_write<32, false>(of);
247 else if (parameters->get_size() == 64)
249 if (parameters->is_big_endian())
251 #ifdef HAVE_TARGET_64_BIG
252 this->do_sized_write<64, true>(of);
259 #ifdef HAVE_TARGET_64_LITTLE
260 this->do_sized_write<64, false>(of);
270 template<int size, bool big_endian>
272 Output_segment_headers::do_sized_write(Output_file* of)
274 const int phdr_size = elfcpp::Elf_sizes<size>::phdr_size;
275 off_t all_phdrs_size = this->segment_list_.size() * phdr_size;
276 unsigned char* view = of->get_output_view(this->offset(),
278 unsigned char* v = view;
279 for (Layout::Segment_list::const_iterator p = this->segment_list_.begin();
280 p != this->segment_list_.end();
283 elfcpp::Phdr_write<size, big_endian> ophdr(v);
284 (*p)->write_header(&ophdr);
288 of->write_output_view(this->offset(), all_phdrs_size, view);
291 // Output_file_header methods.
293 Output_file_header::Output_file_header(const Target* target,
294 const Symbol_table* symtab,
295 const Output_segment_headers* osh)
298 segment_header_(osh),
299 section_header_(NULL),
302 const int size = parameters->get_size();
305 ehdr_size = elfcpp::Elf_sizes<32>::ehdr_size;
307 ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size;
311 this->set_data_size(ehdr_size);
314 // Set the section table information for a file header.
317 Output_file_header::set_section_info(const Output_section_headers* shdrs,
318 const Output_section* shstrtab)
320 this->section_header_ = shdrs;
321 this->shstrtab_ = shstrtab;
324 // Write out the file header.
327 Output_file_header::do_write(Output_file* of)
329 if (parameters->get_size() == 32)
331 if (parameters->is_big_endian())
333 #ifdef HAVE_TARGET_32_BIG
334 this->do_sized_write<32, true>(of);
341 #ifdef HAVE_TARGET_32_LITTLE
342 this->do_sized_write<32, false>(of);
348 else if (parameters->get_size() == 64)
350 if (parameters->is_big_endian())
352 #ifdef HAVE_TARGET_64_BIG
353 this->do_sized_write<64, true>(of);
360 #ifdef HAVE_TARGET_64_LITTLE
361 this->do_sized_write<64, false>(of);
371 // Write out the file header with appropriate size and endianess.
373 template<int size, bool big_endian>
375 Output_file_header::do_sized_write(Output_file* of)
377 gold_assert(this->offset() == 0);
379 int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size;
380 unsigned char* view = of->get_output_view(0, ehdr_size);
381 elfcpp::Ehdr_write<size, big_endian> oehdr(view);
383 unsigned char e_ident[elfcpp::EI_NIDENT];
384 memset(e_ident, 0, elfcpp::EI_NIDENT);
385 e_ident[elfcpp::EI_MAG0] = elfcpp::ELFMAG0;
386 e_ident[elfcpp::EI_MAG1] = elfcpp::ELFMAG1;
387 e_ident[elfcpp::EI_MAG2] = elfcpp::ELFMAG2;
388 e_ident[elfcpp::EI_MAG3] = elfcpp::ELFMAG3;
390 e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS32;
392 e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS64;
395 e_ident[elfcpp::EI_DATA] = (big_endian
396 ? elfcpp::ELFDATA2MSB
397 : elfcpp::ELFDATA2LSB);
398 e_ident[elfcpp::EI_VERSION] = elfcpp::EV_CURRENT;
399 // FIXME: Some targets may need to set EI_OSABI and EI_ABIVERSION.
400 oehdr.put_e_ident(e_ident);
404 if (parameters->output_is_object())
405 e_type = elfcpp::ET_REL;
407 e_type = elfcpp::ET_EXEC;
408 oehdr.put_e_type(e_type);
410 oehdr.put_e_machine(this->target_->machine_code());
411 oehdr.put_e_version(elfcpp::EV_CURRENT);
413 // FIXME: Need to support -e, and target specific entry symbol.
414 Symbol* sym = this->symtab_->lookup("_start");
415 typename Sized_symbol<size>::Value_type v;
420 Sized_symbol<size>* ssym;
421 ssym = this->symtab_->get_sized_symbol SELECT_SIZE_NAME(size) (
422 sym SELECT_SIZE(size));
425 oehdr.put_e_entry(v);
427 oehdr.put_e_phoff(this->segment_header_->offset());
428 oehdr.put_e_shoff(this->section_header_->offset());
430 // FIXME: The target needs to set the flags.
431 oehdr.put_e_flags(0);
433 oehdr.put_e_ehsize(elfcpp::Elf_sizes<size>::ehdr_size);
434 oehdr.put_e_phentsize(elfcpp::Elf_sizes<size>::phdr_size);
435 oehdr.put_e_phnum(this->segment_header_->data_size()
436 / elfcpp::Elf_sizes<size>::phdr_size);
437 oehdr.put_e_shentsize(elfcpp::Elf_sizes<size>::shdr_size);
438 oehdr.put_e_shnum(this->section_header_->data_size()
439 / elfcpp::Elf_sizes<size>::shdr_size);
440 oehdr.put_e_shstrndx(this->shstrtab_->out_shndx());
442 of->write_output_view(0, ehdr_size, view);
445 // Output_data_const methods.
448 Output_data_const::do_write(Output_file* of)
450 of->write(this->offset(), this->data_.data(), this->data_.size());
453 // Output_data_const_buffer methods.
456 Output_data_const_buffer::do_write(Output_file* of)
458 of->write(this->offset(), this->p_, this->data_size());
461 // Output_section_data methods.
463 // Record the output section, and set the entry size and such.
466 Output_section_data::set_output_section(Output_section* os)
468 gold_assert(this->output_section_ == NULL);
469 this->output_section_ = os;
470 this->do_adjust_output_section(os);
473 // Return the section index of the output section.
476 Output_section_data::do_out_shndx() const
478 gold_assert(this->output_section_ != NULL);
479 return this->output_section_->out_shndx();
482 // Output_data_strtab methods.
484 // Set the address. We don't actually care about the address, but we
485 // do set our final size.
488 Output_data_strtab::do_set_address(uint64_t, off_t)
490 this->strtab_->set_string_offsets();
491 this->set_data_size(this->strtab_->get_strtab_size());
494 // Write out a string table.
497 Output_data_strtab::do_write(Output_file* of)
499 this->strtab_->write(of, this->offset());
502 // Output_reloc methods.
504 // Get the symbol index of a relocation.
506 template<bool dynamic, int size, bool big_endian>
508 Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::get_symbol_index()
512 switch (this->local_sym_index_)
518 if (this->u1_.gsym == NULL)
521 index = this->u1_.gsym->dynsym_index();
523 index = this->u1_.gsym->symtab_index();
528 index = this->u1_.os->dynsym_index();
530 index = this->u1_.os->symtab_index();
536 // FIXME: It seems that some targets may need to generate
537 // dynamic relocations against local symbols for some
538 // reasons. This will have to be addressed at some point.
542 index = this->u1_.relobj->symtab_index(this->local_sym_index_);
545 gold_assert(index != -1U);
549 // Write out the offset and info fields of a Rel or Rela relocation
552 template<bool dynamic, int size, bool big_endian>
553 template<typename Write_rel>
555 Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::write_rel(
558 Address address = this->address_;
559 if (this->shndx_ != INVALID_CODE)
562 Output_section* os = this->u2_.relobj->output_section(this->shndx_,
564 gold_assert(os != NULL);
565 address += os->address() + off;
567 else if (this->u2_.od != NULL)
568 address += this->u2_.od->address();
569 wr->put_r_offset(address);
570 wr->put_r_info(elfcpp::elf_r_info<size>(this->get_symbol_index(),
574 // Write out a Rel relocation.
576 template<bool dynamic, int size, bool big_endian>
578 Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::write(
579 unsigned char* pov) const
581 elfcpp::Rel_write<size, big_endian> orel(pov);
582 this->write_rel(&orel);
585 // Write out a Rela relocation.
587 template<bool dynamic, int size, bool big_endian>
589 Output_reloc<elfcpp::SHT_RELA, dynamic, size, big_endian>::write(
590 unsigned char* pov) const
592 elfcpp::Rela_write<size, big_endian> orel(pov);
593 this->rel_.write_rel(&orel);
594 orel.put_r_addend(this->addend_);
597 // Output_data_reloc_base methods.
599 // Adjust the output section.
601 template<int sh_type, bool dynamic, int size, bool big_endian>
603 Output_data_reloc_base<sh_type, dynamic, size, big_endian>
604 ::do_adjust_output_section(Output_section* os)
606 if (sh_type == elfcpp::SHT_REL)
607 os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
608 else if (sh_type == elfcpp::SHT_RELA)
609 os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
613 os->set_should_link_to_dynsym();
615 os->set_should_link_to_symtab();
618 // Write out relocation data.
620 template<int sh_type, bool dynamic, int size, bool big_endian>
622 Output_data_reloc_base<sh_type, dynamic, size, big_endian>::do_write(
625 const off_t off = this->offset();
626 const off_t oview_size = this->data_size();
627 unsigned char* const oview = of->get_output_view(off, oview_size);
629 unsigned char* pov = oview;
630 for (typename Relocs::const_iterator p = this->relocs_.begin();
631 p != this->relocs_.end();
638 gold_assert(pov - oview == oview_size);
640 of->write_output_view(off, oview_size, oview);
642 // We no longer need the relocation entries.
643 this->relocs_.clear();
646 // Output_data_got::Got_entry methods.
648 // Write out the entry.
650 template<int size, bool big_endian>
652 Output_data_got<size, big_endian>::Got_entry::write(unsigned char* pov) const
656 switch (this->local_sym_index_)
660 Symbol* gsym = this->u_.gsym;
662 // If the symbol is resolved locally, we need to write out its
663 // value. Otherwise we just write zero. The target code is
664 // responsible for creating a relocation entry to fill in the
666 if (gsym->final_value_is_known())
668 Sized_symbol<size>* sgsym;
669 // This cast is a bit ugly. We don't want to put a
670 // virtual method in Symbol, because we want Symbol to be
671 // as small as possible.
672 sgsym = static_cast<Sized_symbol<size>*>(gsym);
673 val = sgsym->value();
679 val = this->u_.constant;
683 val = this->u_.object->local_symbol_value(this->local_sym_index_);
687 elfcpp::Swap<size, big_endian>::writeval(pov, val);
690 // Output_data_got methods.
692 // Add an entry for a global symbol to the GOT. This returns true if
693 // this is a new GOT entry, false if the symbol already had a GOT
696 template<int size, bool big_endian>
698 Output_data_got<size, big_endian>::add_global(Symbol* gsym)
700 if (gsym->has_got_offset())
703 this->entries_.push_back(Got_entry(gsym));
704 this->set_got_size();
705 gsym->set_got_offset(this->last_got_offset());
709 // Add an entry for a local symbol to the GOT. This returns true if
710 // this is a new GOT entry, false if the symbol already has a GOT
713 template<int size, bool big_endian>
715 Output_data_got<size, big_endian>::add_local(
716 Sized_relobj<size, big_endian>* object,
719 if (object->local_has_got_offset(symndx))
721 this->entries_.push_back(Got_entry(object, symndx));
722 this->set_got_size();
723 object->set_local_got_offset(symndx, this->last_got_offset());
727 // Write out the GOT.
729 template<int size, bool big_endian>
731 Output_data_got<size, big_endian>::do_write(Output_file* of)
733 const int add = size / 8;
735 const off_t off = this->offset();
736 const off_t oview_size = this->data_size();
737 unsigned char* const oview = of->get_output_view(off, oview_size);
739 unsigned char* pov = oview;
740 for (typename Got_entries::const_iterator p = this->entries_.begin();
741 p != this->entries_.end();
748 gold_assert(pov - oview == oview_size);
750 of->write_output_view(off, oview_size, oview);
752 // We no longer need the GOT entries.
753 this->entries_.clear();
756 // Output_data_dynamic::Dynamic_entry methods.
758 // Write out the entry.
760 template<int size, bool big_endian>
762 Output_data_dynamic::Dynamic_entry::write(
764 const Stringpool* pool
765 ACCEPT_SIZE_ENDIAN) const
767 typename elfcpp::Elf_types<size>::Elf_WXword val;
768 switch (this->classification_)
774 case DYNAMIC_SECTION_ADDRESS:
775 val = this->u_.od->address();
778 case DYNAMIC_SECTION_SIZE:
779 val = this->u_.od->data_size();
784 const Sized_symbol<size>* s =
785 static_cast<const Sized_symbol<size>*>(this->u_.sym);
791 val = pool->get_offset(this->u_.str);
798 elfcpp::Dyn_write<size, big_endian> dw(pov);
799 dw.put_d_tag(this->tag_);
803 // Output_data_dynamic methods.
805 // Adjust the output section to set the entry size.
808 Output_data_dynamic::do_adjust_output_section(Output_section* os)
810 if (parameters->get_size() == 32)
811 os->set_entsize(elfcpp::Elf_sizes<32>::dyn_size);
812 else if (parameters->get_size() == 64)
813 os->set_entsize(elfcpp::Elf_sizes<64>::dyn_size);
818 // Set the final data size.
821 Output_data_dynamic::do_set_address(uint64_t, off_t)
823 // Add the terminating entry.
824 this->add_constant(elfcpp::DT_NULL, 0);
827 if (parameters->get_size() == 32)
828 dyn_size = elfcpp::Elf_sizes<32>::dyn_size;
829 else if (parameters->get_size() == 64)
830 dyn_size = elfcpp::Elf_sizes<64>::dyn_size;
833 this->set_data_size(this->entries_.size() * dyn_size);
836 // Write out the dynamic entries.
839 Output_data_dynamic::do_write(Output_file* of)
841 if (parameters->get_size() == 32)
843 if (parameters->is_big_endian())
845 #ifdef HAVE_TARGET_32_BIG
846 this->sized_write<32, true>(of);
853 #ifdef HAVE_TARGET_32_LITTLE
854 this->sized_write<32, false>(of);
860 else if (parameters->get_size() == 64)
862 if (parameters->is_big_endian())
864 #ifdef HAVE_TARGET_64_BIG
865 this->sized_write<64, true>(of);
872 #ifdef HAVE_TARGET_64_LITTLE
873 this->sized_write<64, false>(of);
883 template<int size, bool big_endian>
885 Output_data_dynamic::sized_write(Output_file* of)
887 const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size;
889 const off_t offset = this->offset();
890 const off_t oview_size = this->data_size();
891 unsigned char* const oview = of->get_output_view(offset, oview_size);
893 unsigned char* pov = oview;
894 for (typename Dynamic_entries::const_iterator p = this->entries_.begin();
895 p != this->entries_.end();
898 p->write SELECT_SIZE_ENDIAN_NAME(size, big_endian)(
899 pov, this->pool_ SELECT_SIZE_ENDIAN(size, big_endian));
903 gold_assert(pov - oview == oview_size);
905 of->write_output_view(offset, oview_size, oview);
907 // We no longer need the dynamic entries.
908 this->entries_.clear();
911 // Output_section::Input_section methods.
913 // Return the data size. For an input section we store the size here.
914 // For an Output_section_data, we have to ask it for the size.
917 Output_section::Input_section::data_size() const
919 if (this->is_input_section())
920 return this->u1_.data_size;
922 return this->u2_.posd->data_size();
925 // Set the address and file offset.
928 Output_section::Input_section::set_address(uint64_t addr, off_t off,
931 if (this->is_input_section())
932 this->u2_.object->set_section_offset(this->shndx_, off - secoff);
934 this->u2_.posd->set_address(addr, off);
937 // Try to turn an input address into an output address.
940 Output_section::Input_section::output_address(const Relobj* object,
943 uint64_t output_section_address,
944 uint64_t *poutput) const
946 if (!this->is_input_section())
947 return this->u2_.posd->output_address(object, shndx, offset,
948 output_section_address, poutput);
951 if (this->shndx_ != shndx
952 || this->u2_.object != object)
955 Output_section* os = object->output_section(shndx, &output_offset);
956 gold_assert(os != NULL);
957 *poutput = output_section_address + output_offset + offset;
962 // Write out the data. We don't have to do anything for an input
963 // section--they are handled via Object::relocate--but this is where
964 // we write out the data for an Output_section_data.
967 Output_section::Input_section::write(Output_file* of)
969 if (!this->is_input_section())
970 this->u2_.posd->write(of);
973 // Output_section methods.
975 // Construct an Output_section. NAME will point into a Stringpool.
977 Output_section::Output_section(const char* name, elfcpp::Elf_Word type,
978 elfcpp::Elf_Xword flags)
992 first_input_offset_(0),
994 needs_symtab_index_(false),
995 needs_dynsym_index_(false),
996 should_link_to_symtab_(false),
997 should_link_to_dynsym_(false)
1001 Output_section::~Output_section()
1005 // Set the entry size.
1008 Output_section::set_entsize(uint64_t v)
1010 if (this->entsize_ == 0)
1013 gold_assert(this->entsize_ == v);
1016 // Add the input section SHNDX, with header SHDR, named SECNAME, in
1017 // OBJECT, to the Output_section. Return the offset of the input
1018 // section within the output section. We don't always keep track of
1019 // input sections for an Output_section. Instead, each Object keeps
1020 // track of the Output_section for each of its input sections.
1022 template<int size, bool big_endian>
1024 Output_section::add_input_section(Relobj* object, unsigned int shndx,
1025 const char* secname,
1026 const elfcpp::Shdr<size, big_endian>& shdr)
1028 elfcpp::Elf_Xword addralign = shdr.get_sh_addralign();
1029 if ((addralign & (addralign - 1)) != 0)
1031 object->error(_("invalid alignment %lu for section \"%s\""),
1032 static_cast<unsigned long>(addralign), secname);
1036 if (addralign > this->addralign_)
1037 this->addralign_ = addralign;
1039 // If this is a SHF_MERGE section, we pass all the input sections to
1040 // a Output_data_merge.
1041 if ((shdr.get_sh_flags() & elfcpp::SHF_MERGE) != 0)
1043 if (this->add_merge_input_section(object, shndx, shdr.get_sh_flags(),
1044 shdr.get_sh_entsize(),
1047 // Tell the relocation routines that they need to call the
1048 // output_address method to determine the final address.
1053 off_t offset_in_section = this->data_size();
1054 off_t aligned_offset_in_section = align_address(offset_in_section,
1057 if (aligned_offset_in_section > offset_in_section
1058 && (shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0
1059 && object->target()->has_code_fill())
1061 // We need to add some fill data. Using fill_list_ when
1062 // possible is an optimization, since we will often have fill
1063 // sections without input sections.
1064 off_t fill_len = aligned_offset_in_section - offset_in_section;
1065 if (this->input_sections_.empty())
1066 this->fills_.push_back(Fill(offset_in_section, fill_len));
1069 // FIXME: When relaxing, the size needs to adjust to
1070 // maintain a constant alignment.
1071 std::string fill_data(object->target()->code_fill(fill_len));
1072 Output_data_const* odc = new Output_data_const(fill_data, 1);
1073 this->input_sections_.push_back(Input_section(odc));
1077 this->set_data_size(aligned_offset_in_section + shdr.get_sh_size());
1079 // We need to keep track of this section if we are already keeping
1080 // track of sections, or if we are relaxing. FIXME: Add test for
1082 if (!this->input_sections_.empty())
1083 this->input_sections_.push_back(Input_section(object, shndx,
1087 return aligned_offset_in_section;
1090 // Add arbitrary data to an output section.
1093 Output_section::add_output_section_data(Output_section_data* posd)
1095 Input_section inp(posd);
1096 this->add_output_section_data(&inp);
1099 // Add arbitrary data to an output section by Input_section.
1102 Output_section::add_output_section_data(Input_section* inp)
1104 if (this->input_sections_.empty())
1105 this->first_input_offset_ = this->data_size();
1107 this->input_sections_.push_back(*inp);
1109 uint64_t addralign = inp->addralign();
1110 if (addralign > this->addralign_)
1111 this->addralign_ = addralign;
1113 inp->set_output_section(this);
1116 // Add a merge section to an output section.
1119 Output_section::add_output_merge_section(Output_section_data* posd,
1120 bool is_string, uint64_t entsize)
1122 Input_section inp(posd, is_string, entsize);
1123 this->add_output_section_data(&inp);
1126 // Add an input section to a SHF_MERGE section.
1129 Output_section::add_merge_input_section(Relobj* object, unsigned int shndx,
1130 uint64_t flags, uint64_t entsize,
1133 // We only merge constants if the alignment is not more than the
1134 // entry size. This could be handled, but it's unusual.
1135 if (addralign > entsize)
1138 bool is_string = (flags & elfcpp::SHF_STRINGS) != 0;
1139 Input_section_list::iterator p;
1140 for (p = this->input_sections_.begin();
1141 p != this->input_sections_.end();
1143 if (p->is_merge_section(is_string, entsize))
1146 // We handle the actual constant merging in Output_merge_data or
1147 // Output_merge_string_data.
1148 if (p != this->input_sections_.end())
1149 p->add_input_section(object, shndx);
1152 Output_section_data* posd;
1154 posd = new Output_merge_data(entsize);
1155 else if (entsize == 1)
1156 posd = new Output_merge_string<char>();
1157 else if (entsize == 2)
1158 posd = new Output_merge_string<uint16_t>();
1159 else if (entsize == 4)
1160 posd = new Output_merge_string<uint32_t>();
1164 this->add_output_merge_section(posd, is_string, entsize);
1165 posd->add_input_section(object, shndx);
1171 // Return the output virtual address of OFFSET relative to the start
1172 // of input section SHNDX in object OBJECT.
1175 Output_section::output_address(const Relobj* object, unsigned int shndx,
1178 uint64_t addr = this->address() + this->first_input_offset_;
1179 for (Input_section_list::const_iterator p = this->input_sections_.begin();
1180 p != this->input_sections_.end();
1183 addr = align_address(addr, p->addralign());
1185 if (p->output_address(object, shndx, offset, addr, &output))
1187 addr += p->data_size();
1190 // If we get here, it means that we don't know the mapping for this
1191 // input section. This might happen in principle if
1192 // add_input_section were called before add_output_section_data.
1193 // But it should never actually happen.
1198 // Set the address of an Output_section. This is where we handle
1199 // setting the addresses of any Output_section_data objects.
1202 Output_section::do_set_address(uint64_t address, off_t startoff)
1204 if (this->input_sections_.empty())
1207 off_t off = startoff + this->first_input_offset_;
1208 for (Input_section_list::iterator p = this->input_sections_.begin();
1209 p != this->input_sections_.end();
1212 off = align_address(off, p->addralign());
1213 p->set_address(address + (off - startoff), off, startoff);
1214 off += p->data_size();
1217 this->set_data_size(off - startoff);
1220 // Write the section header to *OSHDR.
1222 template<int size, bool big_endian>
1224 Output_section::write_header(const Layout* layout,
1225 const Stringpool* secnamepool,
1226 elfcpp::Shdr_write<size, big_endian>* oshdr) const
1228 oshdr->put_sh_name(secnamepool->get_offset(this->name_));
1229 oshdr->put_sh_type(this->type_);
1230 oshdr->put_sh_flags(this->flags_);
1231 oshdr->put_sh_addr(this->address());
1232 oshdr->put_sh_offset(this->offset());
1233 oshdr->put_sh_size(this->data_size());
1234 if (this->link_section_ != NULL)
1235 oshdr->put_sh_link(this->link_section_->out_shndx());
1236 else if (this->should_link_to_symtab_)
1237 oshdr->put_sh_link(layout->symtab_section()->out_shndx());
1238 else if (this->should_link_to_dynsym_)
1239 oshdr->put_sh_link(layout->dynsym_section()->out_shndx());
1241 oshdr->put_sh_link(this->link_);
1242 if (this->info_section_ != NULL)
1243 oshdr->put_sh_info(this->info_section_->out_shndx());
1245 oshdr->put_sh_info(this->info_);
1246 oshdr->put_sh_addralign(this->addralign_);
1247 oshdr->put_sh_entsize(this->entsize_);
1250 // Write out the data. For input sections the data is written out by
1251 // Object::relocate, but we have to handle Output_section_data objects
1255 Output_section::do_write(Output_file* of)
1257 off_t output_section_file_offset = this->offset();
1258 for (Fill_list::iterator p = this->fills_.begin();
1259 p != this->fills_.end();
1262 std::string fill_data(of->target()->code_fill(p->length()));
1263 of->write(output_section_file_offset + p->section_offset(),
1264 fill_data.data(), fill_data.size());
1267 for (Input_section_list::iterator p = this->input_sections_.begin();
1268 p != this->input_sections_.end();
1273 // Output segment methods.
1275 Output_segment::Output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
1286 is_align_known_(false)
1290 // Add an Output_section to an Output_segment.
1293 Output_segment::add_output_section(Output_section* os,
1294 elfcpp::Elf_Word seg_flags,
1297 gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
1298 gold_assert(!this->is_align_known_);
1300 // Update the segment flags.
1301 this->flags_ |= seg_flags;
1303 Output_segment::Output_data_list* pdl;
1304 if (os->type() == elfcpp::SHT_NOBITS)
1305 pdl = &this->output_bss_;
1307 pdl = &this->output_data_;
1309 // So that PT_NOTE segments will work correctly, we need to ensure
1310 // that all SHT_NOTE sections are adjacent. This will normally
1311 // happen automatically, because all the SHT_NOTE input sections
1312 // will wind up in the same output section. However, it is possible
1313 // for multiple SHT_NOTE input sections to have different section
1314 // flags, and thus be in different output sections, but for the
1315 // different section flags to map into the same segment flags and
1316 // thus the same output segment.
1318 // Note that while there may be many input sections in an output
1319 // section, there are normally only a few output sections in an
1320 // output segment. This loop is expected to be fast.
1322 if (os->type() == elfcpp::SHT_NOTE && !pdl->empty())
1324 Output_segment::Output_data_list::iterator p = pdl->end();
1328 if ((*p)->is_section_type(elfcpp::SHT_NOTE))
1330 // We don't worry about the FRONT parameter.
1336 while (p != pdl->begin());
1339 // Similarly, so that PT_TLS segments will work, we need to group
1340 // SHF_TLS sections. An SHF_TLS/SHT_NOBITS section is a special
1341 // case: we group the SHF_TLS/SHT_NOBITS sections right after the
1342 // SHF_TLS/SHT_PROGBITS sections. This lets us set up PT_TLS
1344 if ((os->flags() & elfcpp::SHF_TLS) != 0 && !this->output_data_.empty())
1346 pdl = &this->output_data_;
1347 bool nobits = os->type() == elfcpp::SHT_NOBITS;
1348 bool sawtls = false;
1349 Output_segment::Output_data_list::iterator p = pdl->end();
1354 if ((*p)->is_section_flag_set(elfcpp::SHF_TLS))
1357 // Put a NOBITS section after the first TLS section.
1358 // But a PROGBITS section after the first TLS/PROGBITS
1360 insert = nobits || !(*p)->is_section_type(elfcpp::SHT_NOBITS);
1364 // If we've gone past the TLS sections, but we've seen a
1365 // TLS section, then we need to insert this section now.
1371 // We don't worry about the FRONT parameter.
1377 while (p != pdl->begin());
1379 // There are no TLS sections yet; put this one at the requested
1380 // location in the section list.
1384 pdl->push_front(os);
1389 // Add an Output_data (which is not an Output_section) to the start of
1393 Output_segment::add_initial_output_data(Output_data* od)
1395 gold_assert(!this->is_align_known_);
1396 this->output_data_.push_front(od);
1399 // Return the maximum alignment of the Output_data in Output_segment.
1400 // Once we compute this, we prohibit new sections from being added.
1403 Output_segment::addralign()
1405 if (!this->is_align_known_)
1409 addralign = Output_segment::maximum_alignment(&this->output_data_);
1410 if (addralign > this->align_)
1411 this->align_ = addralign;
1413 addralign = Output_segment::maximum_alignment(&this->output_bss_);
1414 if (addralign > this->align_)
1415 this->align_ = addralign;
1417 this->is_align_known_ = true;
1420 return this->align_;
1423 // Return the maximum alignment of a list of Output_data.
1426 Output_segment::maximum_alignment(const Output_data_list* pdl)
1429 for (Output_data_list::const_iterator p = pdl->begin();
1433 uint64_t addralign = (*p)->addralign();
1434 if (addralign > ret)
1440 // Set the section addresses for an Output_segment. ADDR is the
1441 // address and *POFF is the file offset. Set the section indexes
1442 // starting with *PSHNDX. Return the address of the immediately
1443 // following segment. Update *POFF and *PSHNDX.
1446 Output_segment::set_section_addresses(uint64_t addr, off_t* poff,
1447 unsigned int* pshndx)
1449 gold_assert(this->type_ == elfcpp::PT_LOAD);
1451 this->vaddr_ = addr;
1452 this->paddr_ = addr;
1454 off_t orig_off = *poff;
1455 this->offset_ = orig_off;
1457 *poff = align_address(*poff, this->addralign());
1459 addr = this->set_section_list_addresses(&this->output_data_, addr, poff,
1461 this->filesz_ = *poff - orig_off;
1465 uint64_t ret = this->set_section_list_addresses(&this->output_bss_, addr,
1467 this->memsz_ = *poff - orig_off;
1469 // Ignore the file offset adjustments made by the BSS Output_data
1476 // Set the addresses and file offsets in a list of Output_data
1480 Output_segment::set_section_list_addresses(Output_data_list* pdl,
1481 uint64_t addr, off_t* poff,
1482 unsigned int* pshndx)
1484 off_t startoff = *poff;
1486 off_t off = startoff;
1487 for (Output_data_list::iterator p = pdl->begin();
1491 off = align_address(off, (*p)->addralign());
1492 (*p)->set_address(addr + (off - startoff), off);
1494 // Unless this is a PT_TLS segment, we want to ignore the size
1495 // of a SHF_TLS/SHT_NOBITS section. Such a section does not
1496 // affect the size of a PT_LOAD segment.
1497 if (this->type_ == elfcpp::PT_TLS
1498 || !(*p)->is_section_flag_set(elfcpp::SHF_TLS)
1499 || !(*p)->is_section_type(elfcpp::SHT_NOBITS))
1500 off += (*p)->data_size();
1502 if ((*p)->is_section())
1504 (*p)->set_out_shndx(*pshndx);
1510 return addr + (off - startoff);
1513 // For a non-PT_LOAD segment, set the offset from the sections, if
1517 Output_segment::set_offset()
1519 gold_assert(this->type_ != elfcpp::PT_LOAD);
1521 if (this->output_data_.empty() && this->output_bss_.empty())
1532 const Output_data* first;
1533 if (this->output_data_.empty())
1534 first = this->output_bss_.front();
1536 first = this->output_data_.front();
1537 this->vaddr_ = first->address();
1538 this->paddr_ = this->vaddr_;
1539 this->offset_ = first->offset();
1541 if (this->output_data_.empty())
1545 const Output_data* last_data = this->output_data_.back();
1546 this->filesz_ = (last_data->address()
1547 + last_data->data_size()
1551 const Output_data* last;
1552 if (this->output_bss_.empty())
1553 last = this->output_data_.back();
1555 last = this->output_bss_.back();
1556 this->memsz_ = (last->address()
1561 // Return the number of Output_sections in an Output_segment.
1564 Output_segment::output_section_count() const
1566 return (this->output_section_count_list(&this->output_data_)
1567 + this->output_section_count_list(&this->output_bss_));
1570 // Return the number of Output_sections in an Output_data_list.
1573 Output_segment::output_section_count_list(const Output_data_list* pdl) const
1575 unsigned int count = 0;
1576 for (Output_data_list::const_iterator p = pdl->begin();
1580 if ((*p)->is_section())
1586 // Write the segment data into *OPHDR.
1588 template<int size, bool big_endian>
1590 Output_segment::write_header(elfcpp::Phdr_write<size, big_endian>* ophdr)
1592 ophdr->put_p_type(this->type_);
1593 ophdr->put_p_offset(this->offset_);
1594 ophdr->put_p_vaddr(this->vaddr_);
1595 ophdr->put_p_paddr(this->paddr_);
1596 ophdr->put_p_filesz(this->filesz_);
1597 ophdr->put_p_memsz(this->memsz_);
1598 ophdr->put_p_flags(this->flags_);
1599 ophdr->put_p_align(this->addralign());
1602 // Write the section headers into V.
1604 template<int size, bool big_endian>
1606 Output_segment::write_section_headers(const Layout* layout,
1607 const Stringpool* secnamepool,
1609 unsigned int *pshndx
1610 ACCEPT_SIZE_ENDIAN) const
1612 // Every section that is attached to a segment must be attached to a
1613 // PT_LOAD segment, so we only write out section headers for PT_LOAD
1615 if (this->type_ != elfcpp::PT_LOAD)
1618 v = this->write_section_headers_list
1619 SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
1620 layout, secnamepool, &this->output_data_, v, pshndx
1621 SELECT_SIZE_ENDIAN(size, big_endian));
1622 v = this->write_section_headers_list
1623 SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
1624 layout, secnamepool, &this->output_bss_, v, pshndx
1625 SELECT_SIZE_ENDIAN(size, big_endian));
1629 template<int size, bool big_endian>
1631 Output_segment::write_section_headers_list(const Layout* layout,
1632 const Stringpool* secnamepool,
1633 const Output_data_list* pdl,
1635 unsigned int* pshndx
1636 ACCEPT_SIZE_ENDIAN) const
1638 const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
1639 for (Output_data_list::const_iterator p = pdl->begin();
1643 if ((*p)->is_section())
1645 const Output_section* ps = static_cast<const Output_section*>(*p);
1646 gold_assert(*pshndx == ps->out_shndx());
1647 elfcpp::Shdr_write<size, big_endian> oshdr(v);
1648 ps->write_header(layout, secnamepool, &oshdr);
1656 // Output_file methods.
1658 Output_file::Output_file(const General_options& options, Target* target)
1659 : options_(options),
1661 name_(options.output_file_name()),
1668 // Open the output file.
1671 Output_file::open(off_t file_size)
1673 this->file_size_ = file_size;
1675 // Unlink the file first; otherwise the open() may fail if the file
1676 // is busy (e.g. it's an executable that's currently being executed).
1678 // However, the linker may be part of a system where a zero-length
1679 // file is created for it to write to, with tight permissions (gcc
1680 // 2.95 did something like this). Unlinking the file would work
1681 // around those permission controls, so we only unlink if the file
1682 // has a non-zero size. We also unlink only regular files to avoid
1683 // trouble with directories/etc.
1685 // If we fail, continue; this command is merely a best-effort attempt
1686 // to improve the odds for open().
1688 // FIXME: unlink the file if it's a symlink, even a symlink to a dir.
1689 // Or do we want to follow the symlink and unlink its target?
1691 if (::stat(this->name_, &s) == 0 && s.st_size != 0 && S_ISREG(s.st_mode))
1692 ::unlink(this->name_);
1694 int mode = parameters->output_is_object() ? 0666 : 0777;
1695 int o = ::open(this->name_, O_RDWR | O_CREAT | O_TRUNC, mode);
1697 gold_fatal(_("%s: open: %s"), this->name_, strerror(errno));
1700 // Write out one byte to make the file the right size.
1701 if (::lseek(o, file_size - 1, SEEK_SET) < 0)
1702 gold_fatal(_("%s: lseek: %s"), this->name_, strerror(errno));
1704 if (::write(o, &b, 1) != 1)
1705 gold_fatal(_("%s: write: %s"), this->name_, strerror(errno));
1707 // Map the file into memory.
1708 void* base = ::mmap(NULL, file_size, PROT_READ | PROT_WRITE,
1710 if (base == MAP_FAILED)
1711 gold_fatal(_("%s: mmap: %s"), this->name_, strerror(errno));
1712 this->base_ = static_cast<unsigned char*>(base);
1715 // Close the output file.
1718 Output_file::close()
1720 if (::munmap(this->base_, this->file_size_) < 0)
1721 gold_error(_("%s: munmap: %s\n"), this->name_, strerror(errno));
1724 if (::close(this->o_) < 0)
1725 gold_error(_("%s: close: %s"), this->name_, strerror(errno));
1729 // Instantiate the templates we need. We could use the configure
1730 // script to restrict this to only the ones for implemented targets.
1732 #ifdef HAVE_TARGET_32_LITTLE
1735 Output_section::add_input_section<32, false>(
1738 const char* secname,
1739 const elfcpp::Shdr<32, false>& shdr);
1742 #ifdef HAVE_TARGET_32_BIG
1745 Output_section::add_input_section<32, true>(
1748 const char* secname,
1749 const elfcpp::Shdr<32, true>& shdr);
1752 #ifdef HAVE_TARGET_64_LITTLE
1755 Output_section::add_input_section<64, false>(
1758 const char* secname,
1759 const elfcpp::Shdr<64, false>& shdr);
1762 #ifdef HAVE_TARGET_64_BIG
1765 Output_section::add_input_section<64, true>(
1768 const char* secname,
1769 const elfcpp::Shdr<64, true>& shdr);
1772 #ifdef HAVE_TARGET_32_LITTLE
1774 class Output_data_reloc<elfcpp::SHT_REL, false, 32, false>;
1777 #ifdef HAVE_TARGET_32_BIG
1779 class Output_data_reloc<elfcpp::SHT_REL, false, 32, true>;
1782 #ifdef HAVE_TARGET_64_LITTLE
1784 class Output_data_reloc<elfcpp::SHT_REL, false, 64, false>;
1787 #ifdef HAVE_TARGET_64_BIG
1789 class Output_data_reloc<elfcpp::SHT_REL, false, 64, true>;
1792 #ifdef HAVE_TARGET_32_LITTLE
1794 class Output_data_reloc<elfcpp::SHT_REL, true, 32, false>;
1797 #ifdef HAVE_TARGET_32_BIG
1799 class Output_data_reloc<elfcpp::SHT_REL, true, 32, true>;
1802 #ifdef HAVE_TARGET_64_LITTLE
1804 class Output_data_reloc<elfcpp::SHT_REL, true, 64, false>;
1807 #ifdef HAVE_TARGET_64_BIG
1809 class Output_data_reloc<elfcpp::SHT_REL, true, 64, true>;
1812 #ifdef HAVE_TARGET_32_LITTLE
1814 class Output_data_reloc<elfcpp::SHT_RELA, false, 32, false>;
1817 #ifdef HAVE_TARGET_32_BIG
1819 class Output_data_reloc<elfcpp::SHT_RELA, false, 32, true>;
1822 #ifdef HAVE_TARGET_64_LITTLE
1824 class Output_data_reloc<elfcpp::SHT_RELA, false, 64, false>;
1827 #ifdef HAVE_TARGET_64_BIG
1829 class Output_data_reloc<elfcpp::SHT_RELA, false, 64, true>;
1832 #ifdef HAVE_TARGET_32_LITTLE
1834 class Output_data_reloc<elfcpp::SHT_RELA, true, 32, false>;
1837 #ifdef HAVE_TARGET_32_BIG
1839 class Output_data_reloc<elfcpp::SHT_RELA, true, 32, true>;
1842 #ifdef HAVE_TARGET_64_LITTLE
1844 class Output_data_reloc<elfcpp::SHT_RELA, true, 64, false>;
1847 #ifdef HAVE_TARGET_64_BIG
1849 class Output_data_reloc<elfcpp::SHT_RELA, true, 64, true>;
1852 #ifdef HAVE_TARGET_32_LITTLE
1854 class Output_data_got<32, false>;
1857 #ifdef HAVE_TARGET_32_BIG
1859 class Output_data_got<32, true>;
1862 #ifdef HAVE_TARGET_64_LITTLE
1864 class Output_data_got<64, false>;
1867 #ifdef HAVE_TARGET_64_BIG
1869 class Output_data_got<64, true>;
1872 } // End namespace gold.