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.
32 #include "libiberty.h" // for unlink_if_ordinary()
34 #include "parameters.h"
44 // Output_data variables.
46 bool Output_data::sizes_are_fixed;
48 // Output_data methods.
50 Output_data::~Output_data()
54 // Set the address and offset.
57 Output_data::set_address(uint64_t addr, off_t off)
59 this->address_ = addr;
62 // Let the child class know.
63 this->do_set_address(addr, off);
66 // Return the default alignment for the target size.
69 Output_data::default_alignment()
71 return Output_data::default_alignment_for_size(parameters->get_size());
74 // Return the default alignment for a size--32 or 64.
77 Output_data::default_alignment_for_size(int size)
87 // Output_section_header methods. This currently assumes that the
88 // segment and section lists are complete at construction time.
90 Output_section_headers::Output_section_headers(
92 const Layout::Segment_list* segment_list,
93 const Layout::Section_list* unattached_section_list,
94 const Stringpool* secnamepool)
96 segment_list_(segment_list),
97 unattached_section_list_(unattached_section_list),
98 secnamepool_(secnamepool)
100 // Count all the sections. Start with 1 for the null section.
102 for (Layout::Segment_list::const_iterator p = segment_list->begin();
103 p != segment_list->end();
105 if ((*p)->type() == elfcpp::PT_LOAD)
106 count += (*p)->output_section_count();
107 count += unattached_section_list->size();
109 const int size = parameters->get_size();
112 shdr_size = elfcpp::Elf_sizes<32>::shdr_size;
114 shdr_size = elfcpp::Elf_sizes<64>::shdr_size;
118 this->set_data_size(count * shdr_size);
121 // Write out the section headers.
124 Output_section_headers::do_write(Output_file* of)
126 if (parameters->get_size() == 32)
128 if (parameters->is_big_endian())
130 #ifdef HAVE_TARGET_32_BIG
131 this->do_sized_write<32, true>(of);
138 #ifdef HAVE_TARGET_32_LITTLE
139 this->do_sized_write<32, false>(of);
145 else if (parameters->get_size() == 64)
147 if (parameters->is_big_endian())
149 #ifdef HAVE_TARGET_64_BIG
150 this->do_sized_write<64, true>(of);
157 #ifdef HAVE_TARGET_64_LITTLE
158 this->do_sized_write<64, false>(of);
168 template<int size, bool big_endian>
170 Output_section_headers::do_sized_write(Output_file* of)
172 off_t all_shdrs_size = this->data_size();
173 unsigned char* view = of->get_output_view(this->offset(), all_shdrs_size);
175 const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
176 unsigned char* v = view;
179 typename elfcpp::Shdr_write<size, big_endian> oshdr(v);
180 oshdr.put_sh_name(0);
181 oshdr.put_sh_type(elfcpp::SHT_NULL);
182 oshdr.put_sh_flags(0);
183 oshdr.put_sh_addr(0);
184 oshdr.put_sh_offset(0);
185 oshdr.put_sh_size(0);
186 oshdr.put_sh_link(0);
187 oshdr.put_sh_info(0);
188 oshdr.put_sh_addralign(0);
189 oshdr.put_sh_entsize(0);
195 for (Layout::Segment_list::const_iterator p = this->segment_list_->begin();
196 p != this->segment_list_->end();
198 v = (*p)->write_section_headers SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
199 this->layout_, this->secnamepool_, v, &shndx
200 SELECT_SIZE_ENDIAN(size, big_endian));
201 for (Layout::Section_list::const_iterator p =
202 this->unattached_section_list_->begin();
203 p != this->unattached_section_list_->end();
206 gold_assert(shndx == (*p)->out_shndx());
207 elfcpp::Shdr_write<size, big_endian> oshdr(v);
208 (*p)->write_header(this->layout_, this->secnamepool_, &oshdr);
213 of->write_output_view(this->offset(), all_shdrs_size, view);
216 // Output_segment_header methods.
218 Output_segment_headers::Output_segment_headers(
219 const Layout::Segment_list& segment_list)
220 : segment_list_(segment_list)
222 const int size = parameters->get_size();
225 phdr_size = elfcpp::Elf_sizes<32>::phdr_size;
227 phdr_size = elfcpp::Elf_sizes<64>::phdr_size;
231 this->set_data_size(segment_list.size() * phdr_size);
235 Output_segment_headers::do_write(Output_file* of)
237 if (parameters->get_size() == 32)
239 if (parameters->is_big_endian())
241 #ifdef HAVE_TARGET_32_BIG
242 this->do_sized_write<32, true>(of);
249 #ifdef HAVE_TARGET_32_LITTLE
250 this->do_sized_write<32, false>(of);
256 else if (parameters->get_size() == 64)
258 if (parameters->is_big_endian())
260 #ifdef HAVE_TARGET_64_BIG
261 this->do_sized_write<64, true>(of);
268 #ifdef HAVE_TARGET_64_LITTLE
269 this->do_sized_write<64, false>(of);
279 template<int size, bool big_endian>
281 Output_segment_headers::do_sized_write(Output_file* of)
283 const int phdr_size = elfcpp::Elf_sizes<size>::phdr_size;
284 off_t all_phdrs_size = this->segment_list_.size() * phdr_size;
285 unsigned char* view = of->get_output_view(this->offset(),
287 unsigned char* v = view;
288 for (Layout::Segment_list::const_iterator p = this->segment_list_.begin();
289 p != this->segment_list_.end();
292 elfcpp::Phdr_write<size, big_endian> ophdr(v);
293 (*p)->write_header(&ophdr);
297 of->write_output_view(this->offset(), all_phdrs_size, view);
300 // Output_file_header methods.
302 Output_file_header::Output_file_header(const Target* target,
303 const Symbol_table* symtab,
304 const Output_segment_headers* osh)
307 segment_header_(osh),
308 section_header_(NULL),
311 const int size = parameters->get_size();
314 ehdr_size = elfcpp::Elf_sizes<32>::ehdr_size;
316 ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size;
320 this->set_data_size(ehdr_size);
323 // Set the section table information for a file header.
326 Output_file_header::set_section_info(const Output_section_headers* shdrs,
327 const Output_section* shstrtab)
329 this->section_header_ = shdrs;
330 this->shstrtab_ = shstrtab;
333 // Write out the file header.
336 Output_file_header::do_write(Output_file* of)
338 if (parameters->get_size() == 32)
340 if (parameters->is_big_endian())
342 #ifdef HAVE_TARGET_32_BIG
343 this->do_sized_write<32, true>(of);
350 #ifdef HAVE_TARGET_32_LITTLE
351 this->do_sized_write<32, false>(of);
357 else if (parameters->get_size() == 64)
359 if (parameters->is_big_endian())
361 #ifdef HAVE_TARGET_64_BIG
362 this->do_sized_write<64, true>(of);
369 #ifdef HAVE_TARGET_64_LITTLE
370 this->do_sized_write<64, false>(of);
380 // Write out the file header with appropriate size and endianess.
382 template<int size, bool big_endian>
384 Output_file_header::do_sized_write(Output_file* of)
386 gold_assert(this->offset() == 0);
388 int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size;
389 unsigned char* view = of->get_output_view(0, ehdr_size);
390 elfcpp::Ehdr_write<size, big_endian> oehdr(view);
392 unsigned char e_ident[elfcpp::EI_NIDENT];
393 memset(e_ident, 0, elfcpp::EI_NIDENT);
394 e_ident[elfcpp::EI_MAG0] = elfcpp::ELFMAG0;
395 e_ident[elfcpp::EI_MAG1] = elfcpp::ELFMAG1;
396 e_ident[elfcpp::EI_MAG2] = elfcpp::ELFMAG2;
397 e_ident[elfcpp::EI_MAG3] = elfcpp::ELFMAG3;
399 e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS32;
401 e_ident[elfcpp::EI_CLASS] = elfcpp::ELFCLASS64;
404 e_ident[elfcpp::EI_DATA] = (big_endian
405 ? elfcpp::ELFDATA2MSB
406 : elfcpp::ELFDATA2LSB);
407 e_ident[elfcpp::EI_VERSION] = elfcpp::EV_CURRENT;
408 // FIXME: Some targets may need to set EI_OSABI and EI_ABIVERSION.
409 oehdr.put_e_ident(e_ident);
412 if (parameters->output_is_object())
413 e_type = elfcpp::ET_REL;
414 else if (parameters->output_is_shared())
415 e_type = elfcpp::ET_DYN;
417 e_type = elfcpp::ET_EXEC;
418 oehdr.put_e_type(e_type);
420 oehdr.put_e_machine(this->target_->machine_code());
421 oehdr.put_e_version(elfcpp::EV_CURRENT);
423 // FIXME: Need to support -e, and target specific entry symbol.
424 Symbol* sym = this->symtab_->lookup("_start");
425 typename Sized_symbol<size>::Value_type v;
430 Sized_symbol<size>* ssym;
431 ssym = this->symtab_->get_sized_symbol SELECT_SIZE_NAME(size) (
432 sym SELECT_SIZE(size));
435 oehdr.put_e_entry(v);
437 oehdr.put_e_phoff(this->segment_header_->offset());
438 oehdr.put_e_shoff(this->section_header_->offset());
440 // FIXME: The target needs to set the flags.
441 oehdr.put_e_flags(0);
443 oehdr.put_e_ehsize(elfcpp::Elf_sizes<size>::ehdr_size);
444 oehdr.put_e_phentsize(elfcpp::Elf_sizes<size>::phdr_size);
445 oehdr.put_e_phnum(this->segment_header_->data_size()
446 / elfcpp::Elf_sizes<size>::phdr_size);
447 oehdr.put_e_shentsize(elfcpp::Elf_sizes<size>::shdr_size);
448 oehdr.put_e_shnum(this->section_header_->data_size()
449 / elfcpp::Elf_sizes<size>::shdr_size);
450 oehdr.put_e_shstrndx(this->shstrtab_->out_shndx());
452 of->write_output_view(0, ehdr_size, view);
455 // Output_data_const methods.
458 Output_data_const::do_write(Output_file* of)
460 of->write(this->offset(), this->data_.data(), this->data_.size());
463 // Output_data_const_buffer methods.
466 Output_data_const_buffer::do_write(Output_file* of)
468 of->write(this->offset(), this->p_, this->data_size());
471 // Output_section_data methods.
473 // Record the output section, and set the entry size and such.
476 Output_section_data::set_output_section(Output_section* os)
478 gold_assert(this->output_section_ == NULL);
479 this->output_section_ = os;
480 this->do_adjust_output_section(os);
483 // Return the section index of the output section.
486 Output_section_data::do_out_shndx() const
488 gold_assert(this->output_section_ != NULL);
489 return this->output_section_->out_shndx();
492 // Output_data_strtab methods.
494 // Set the address. We don't actually care about the address, but we
495 // do set our final size.
498 Output_data_strtab::do_set_address(uint64_t, off_t)
500 this->strtab_->set_string_offsets();
501 this->set_data_size(this->strtab_->get_strtab_size());
504 // Write out a string table.
507 Output_data_strtab::do_write(Output_file* of)
509 this->strtab_->write(of, this->offset());
512 // Output_reloc methods.
514 // Get the symbol index of a relocation.
516 template<bool dynamic, int size, bool big_endian>
518 Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::get_symbol_index()
522 switch (this->local_sym_index_)
528 if (this->u1_.gsym == NULL)
531 index = this->u1_.gsym->dynsym_index();
533 index = this->u1_.gsym->symtab_index();
538 index = this->u1_.os->dynsym_index();
540 index = this->u1_.os->symtab_index();
544 // Relocations without symbols use a symbol index of 0.
551 // FIXME: It seems that some targets may need to generate
552 // dynamic relocations against local symbols for some
553 // reasons. This will have to be addressed at some point.
557 index = this->u1_.relobj->symtab_index(this->local_sym_index_);
560 gold_assert(index != -1U);
564 // Write out the offset and info fields of a Rel or Rela relocation
567 template<bool dynamic, int size, bool big_endian>
568 template<typename Write_rel>
570 Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::write_rel(
573 Address address = this->address_;
574 if (this->shndx_ != INVALID_CODE)
577 Output_section* os = this->u2_.relobj->output_section(this->shndx_,
579 gold_assert(os != NULL);
581 address += os->address() + off;
584 address = os->output_address(this->u2_.relobj, this->shndx_,
586 gold_assert(address != -1U);
589 else if (this->u2_.od != NULL)
590 address += this->u2_.od->address();
591 wr->put_r_offset(address);
592 wr->put_r_info(elfcpp::elf_r_info<size>(this->get_symbol_index(),
596 // Write out a Rel relocation.
598 template<bool dynamic, int size, bool big_endian>
600 Output_reloc<elfcpp::SHT_REL, dynamic, size, big_endian>::write(
601 unsigned char* pov) const
603 elfcpp::Rel_write<size, big_endian> orel(pov);
604 this->write_rel(&orel);
607 // Write out a Rela relocation.
609 template<bool dynamic, int size, bool big_endian>
611 Output_reloc<elfcpp::SHT_RELA, dynamic, size, big_endian>::write(
612 unsigned char* pov) const
614 elfcpp::Rela_write<size, big_endian> orel(pov);
615 this->rel_.write_rel(&orel);
616 orel.put_r_addend(this->addend_);
619 // Output_data_reloc_base methods.
621 // Adjust the output section.
623 template<int sh_type, bool dynamic, int size, bool big_endian>
625 Output_data_reloc_base<sh_type, dynamic, size, big_endian>
626 ::do_adjust_output_section(Output_section* os)
628 if (sh_type == elfcpp::SHT_REL)
629 os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
630 else if (sh_type == elfcpp::SHT_RELA)
631 os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
635 os->set_should_link_to_dynsym();
637 os->set_should_link_to_symtab();
640 // Write out relocation data.
642 template<int sh_type, bool dynamic, int size, bool big_endian>
644 Output_data_reloc_base<sh_type, dynamic, size, big_endian>::do_write(
647 const off_t off = this->offset();
648 const off_t oview_size = this->data_size();
649 unsigned char* const oview = of->get_output_view(off, oview_size);
651 unsigned char* pov = oview;
652 for (typename Relocs::const_iterator p = this->relocs_.begin();
653 p != this->relocs_.end();
660 gold_assert(pov - oview == oview_size);
662 of->write_output_view(off, oview_size, oview);
664 // We no longer need the relocation entries.
665 this->relocs_.clear();
668 // Output_data_got::Got_entry methods.
670 // Write out the entry.
672 template<int size, bool big_endian>
674 Output_data_got<size, big_endian>::Got_entry::write(unsigned char* pov) const
678 switch (this->local_sym_index_)
682 Symbol* gsym = this->u_.gsym;
684 // If the symbol is resolved locally, we need to write out its
685 // value. Otherwise we just write zero. The target code is
686 // responsible for creating a relocation entry to fill in the
687 // value at runtime. For non-preemptible symbols in a shared
688 // library, the target will need to record whether or not the
689 // value should be written (e.g., it may use a RELATIVE
691 if (gsym->final_value_is_known() || gsym->needs_value_in_got())
693 Sized_symbol<size>* sgsym;
694 // This cast is a bit ugly. We don't want to put a
695 // virtual method in Symbol, because we want Symbol to be
696 // as small as possible.
697 sgsym = static_cast<Sized_symbol<size>*>(gsym);
698 val = sgsym->value();
704 val = this->u_.constant;
708 val = this->u_.object->local_symbol_value(this->local_sym_index_);
712 elfcpp::Swap<size, big_endian>::writeval(pov, val);
715 // Output_data_got methods.
717 // Add an entry for a global symbol to the GOT. This returns true if
718 // this is a new GOT entry, false if the symbol already had a GOT
721 template<int size, bool big_endian>
723 Output_data_got<size, big_endian>::add_global(Symbol* gsym)
725 if (gsym->has_got_offset())
728 this->entries_.push_back(Got_entry(gsym));
729 this->set_got_size();
730 gsym->set_got_offset(this->last_got_offset());
734 // Add an entry for a local symbol to the GOT. This returns true if
735 // this is a new GOT entry, false if the symbol already has a GOT
738 template<int size, bool big_endian>
740 Output_data_got<size, big_endian>::add_local(
741 Sized_relobj<size, big_endian>* object,
744 if (object->local_has_got_offset(symndx))
746 this->entries_.push_back(Got_entry(object, symndx));
747 this->set_got_size();
748 object->set_local_got_offset(symndx, this->last_got_offset());
752 // Write out the GOT.
754 template<int size, bool big_endian>
756 Output_data_got<size, big_endian>::do_write(Output_file* of)
758 const int add = size / 8;
760 const off_t off = this->offset();
761 const off_t oview_size = this->data_size();
762 unsigned char* const oview = of->get_output_view(off, oview_size);
764 unsigned char* pov = oview;
765 for (typename Got_entries::const_iterator p = this->entries_.begin();
766 p != this->entries_.end();
773 gold_assert(pov - oview == oview_size);
775 of->write_output_view(off, oview_size, oview);
777 // We no longer need the GOT entries.
778 this->entries_.clear();
781 // Output_data_dynamic::Dynamic_entry methods.
783 // Write out the entry.
785 template<int size, bool big_endian>
787 Output_data_dynamic::Dynamic_entry::write(
789 const Stringpool* pool
790 ACCEPT_SIZE_ENDIAN) const
792 typename elfcpp::Elf_types<size>::Elf_WXword val;
793 switch (this->classification_)
799 case DYNAMIC_SECTION_ADDRESS:
800 val = this->u_.od->address();
803 case DYNAMIC_SECTION_SIZE:
804 val = this->u_.od->data_size();
809 const Sized_symbol<size>* s =
810 static_cast<const Sized_symbol<size>*>(this->u_.sym);
816 val = pool->get_offset(this->u_.str);
823 elfcpp::Dyn_write<size, big_endian> dw(pov);
824 dw.put_d_tag(this->tag_);
828 // Output_data_dynamic methods.
830 // Adjust the output section to set the entry size.
833 Output_data_dynamic::do_adjust_output_section(Output_section* os)
835 if (parameters->get_size() == 32)
836 os->set_entsize(elfcpp::Elf_sizes<32>::dyn_size);
837 else if (parameters->get_size() == 64)
838 os->set_entsize(elfcpp::Elf_sizes<64>::dyn_size);
843 // Set the final data size.
846 Output_data_dynamic::do_set_address(uint64_t, off_t)
848 // Add the terminating entry.
849 this->add_constant(elfcpp::DT_NULL, 0);
852 if (parameters->get_size() == 32)
853 dyn_size = elfcpp::Elf_sizes<32>::dyn_size;
854 else if (parameters->get_size() == 64)
855 dyn_size = elfcpp::Elf_sizes<64>::dyn_size;
858 this->set_data_size(this->entries_.size() * dyn_size);
861 // Write out the dynamic entries.
864 Output_data_dynamic::do_write(Output_file* of)
866 if (parameters->get_size() == 32)
868 if (parameters->is_big_endian())
870 #ifdef HAVE_TARGET_32_BIG
871 this->sized_write<32, true>(of);
878 #ifdef HAVE_TARGET_32_LITTLE
879 this->sized_write<32, false>(of);
885 else if (parameters->get_size() == 64)
887 if (parameters->is_big_endian())
889 #ifdef HAVE_TARGET_64_BIG
890 this->sized_write<64, true>(of);
897 #ifdef HAVE_TARGET_64_LITTLE
898 this->sized_write<64, false>(of);
908 template<int size, bool big_endian>
910 Output_data_dynamic::sized_write(Output_file* of)
912 const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size;
914 const off_t offset = this->offset();
915 const off_t oview_size = this->data_size();
916 unsigned char* const oview = of->get_output_view(offset, oview_size);
918 unsigned char* pov = oview;
919 for (typename Dynamic_entries::const_iterator p = this->entries_.begin();
920 p != this->entries_.end();
923 p->write SELECT_SIZE_ENDIAN_NAME(size, big_endian)(
924 pov, this->pool_ SELECT_SIZE_ENDIAN(size, big_endian));
928 gold_assert(pov - oview == oview_size);
930 of->write_output_view(offset, oview_size, oview);
932 // We no longer need the dynamic entries.
933 this->entries_.clear();
936 // Output_section::Input_section methods.
938 // Return the data size. For an input section we store the size here.
939 // For an Output_section_data, we have to ask it for the size.
942 Output_section::Input_section::data_size() const
944 if (this->is_input_section())
945 return this->u1_.data_size;
947 return this->u2_.posd->data_size();
950 // Set the address and file offset.
953 Output_section::Input_section::set_address(uint64_t addr, off_t off,
956 if (this->is_input_section())
957 this->u2_.object->set_section_offset(this->shndx_, off - secoff);
959 this->u2_.posd->set_address(addr, off);
962 // Try to turn an input offset into an output offset.
965 Output_section::Input_section::output_offset(const Relobj* object,
968 off_t *poutput) const
970 if (!this->is_input_section())
971 return this->u2_.posd->output_offset(object, shndx, offset, poutput);
974 if (this->shndx_ != shndx || this->u2_.object != object)
977 Output_section* os = object->output_section(shndx, &output_offset);
978 gold_assert(os != NULL);
979 gold_assert(output_offset != -1);
980 *poutput = output_offset + offset;
985 // Write out the data. We don't have to do anything for an input
986 // section--they are handled via Object::relocate--but this is where
987 // we write out the data for an Output_section_data.
990 Output_section::Input_section::write(Output_file* of)
992 if (!this->is_input_section())
993 this->u2_.posd->write(of);
996 // Output_section methods.
998 // Construct an Output_section. NAME will point into a Stringpool.
1000 Output_section::Output_section(const char* name, elfcpp::Elf_Word type,
1001 elfcpp::Elf_Xword flags)
1005 link_section_(NULL),
1007 info_section_(NULL),
1015 first_input_offset_(0),
1017 needs_symtab_index_(false),
1018 needs_dynsym_index_(false),
1019 should_link_to_symtab_(false),
1020 should_link_to_dynsym_(false),
1021 after_input_sections_(false)
1025 Output_section::~Output_section()
1029 // Set the entry size.
1032 Output_section::set_entsize(uint64_t v)
1034 if (this->entsize_ == 0)
1037 gold_assert(this->entsize_ == v);
1040 // Add the input section SHNDX, with header SHDR, named SECNAME, in
1041 // OBJECT, to the Output_section. RELOC_SHNDX is the index of a
1042 // relocation section which applies to this section, or 0 if none, or
1043 // -1U if more than one. Return the offset of the input section
1044 // within the output section. Return -1 if the input section will
1045 // receive special handling. In the normal case we don't always keep
1046 // track of input sections for an Output_section. Instead, each
1047 // Object keeps track of the Output_section for each of its input
1050 template<int size, bool big_endian>
1052 Output_section::add_input_section(Sized_relobj<size, big_endian>* object,
1054 const char* secname,
1055 const elfcpp::Shdr<size, big_endian>& shdr,
1056 unsigned int reloc_shndx)
1058 elfcpp::Elf_Xword addralign = shdr.get_sh_addralign();
1059 if ((addralign & (addralign - 1)) != 0)
1061 object->error(_("invalid alignment %lu for section \"%s\""),
1062 static_cast<unsigned long>(addralign), secname);
1066 if (addralign > this->addralign_)
1067 this->addralign_ = addralign;
1069 // If this is a SHF_MERGE section, we pass all the input sections to
1070 // a Output_data_merge. We don't try to handle relocations for such
1072 if ((shdr.get_sh_flags() & elfcpp::SHF_MERGE) != 0
1073 && reloc_shndx == 0)
1075 if (this->add_merge_input_section(object, shndx, shdr.get_sh_flags(),
1076 shdr.get_sh_entsize(),
1079 // Tell the relocation routines that they need to call the
1080 // output_offset method to determine the final address.
1085 off_t offset_in_section = this->data_size();
1086 off_t aligned_offset_in_section = align_address(offset_in_section,
1089 if (aligned_offset_in_section > offset_in_section
1090 && (shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0
1091 && object->target()->has_code_fill())
1093 // We need to add some fill data. Using fill_list_ when
1094 // possible is an optimization, since we will often have fill
1095 // sections without input sections.
1096 off_t fill_len = aligned_offset_in_section - offset_in_section;
1097 if (this->input_sections_.empty())
1098 this->fills_.push_back(Fill(offset_in_section, fill_len));
1101 // FIXME: When relaxing, the size needs to adjust to
1102 // maintain a constant alignment.
1103 std::string fill_data(object->target()->code_fill(fill_len));
1104 Output_data_const* odc = new Output_data_const(fill_data, 1);
1105 this->input_sections_.push_back(Input_section(odc));
1109 this->set_data_size(aligned_offset_in_section + shdr.get_sh_size());
1111 // We need to keep track of this section if we are already keeping
1112 // track of sections, or if we are relaxing. FIXME: Add test for
1114 if (!this->input_sections_.empty())
1115 this->input_sections_.push_back(Input_section(object, shndx,
1119 return aligned_offset_in_section;
1122 // Add arbitrary data to an output section.
1125 Output_section::add_output_section_data(Output_section_data* posd)
1127 Input_section inp(posd);
1128 this->add_output_section_data(&inp);
1131 // Add arbitrary data to an output section by Input_section.
1134 Output_section::add_output_section_data(Input_section* inp)
1136 if (this->input_sections_.empty())
1137 this->first_input_offset_ = this->data_size();
1139 this->input_sections_.push_back(*inp);
1141 uint64_t addralign = inp->addralign();
1142 if (addralign > this->addralign_)
1143 this->addralign_ = addralign;
1145 inp->set_output_section(this);
1148 // Add a merge section to an output section.
1151 Output_section::add_output_merge_section(Output_section_data* posd,
1152 bool is_string, uint64_t entsize)
1154 Input_section inp(posd, is_string, entsize);
1155 this->add_output_section_data(&inp);
1158 // Add an input section to a SHF_MERGE section.
1161 Output_section::add_merge_input_section(Relobj* object, unsigned int shndx,
1162 uint64_t flags, uint64_t entsize,
1165 bool is_string = (flags & elfcpp::SHF_STRINGS) != 0;
1167 // We only merge strings if the alignment is not more than the
1168 // character size. This could be handled, but it's unusual.
1169 if (is_string && addralign > entsize)
1172 Input_section_list::iterator p;
1173 for (p = this->input_sections_.begin();
1174 p != this->input_sections_.end();
1176 if (p->is_merge_section(is_string, entsize, addralign))
1179 // We handle the actual constant merging in Output_merge_data or
1180 // Output_merge_string_data.
1181 if (p != this->input_sections_.end())
1182 p->add_input_section(object, shndx);
1185 Output_section_data* posd;
1187 posd = new Output_merge_data(entsize, addralign);
1188 else if (entsize == 1)
1189 posd = new Output_merge_string<char>(addralign);
1190 else if (entsize == 2)
1191 posd = new Output_merge_string<uint16_t>(addralign);
1192 else if (entsize == 4)
1193 posd = new Output_merge_string<uint32_t>(addralign);
1197 this->add_output_merge_section(posd, is_string, entsize);
1198 posd->add_input_section(object, shndx);
1204 // Given an address OFFSET relative to the start of input section
1205 // SHNDX in OBJECT, return whether this address is being included in
1206 // the final link. This should only be called if SHNDX in OBJECT has
1207 // a special mapping.
1210 Output_section::is_input_address_mapped(const Relobj* object,
1214 gold_assert(object->is_section_specially_mapped(shndx));
1216 for (Input_section_list::const_iterator p = this->input_sections_.begin();
1217 p != this->input_sections_.end();
1220 off_t output_offset;
1221 if (p->output_offset(object, shndx, offset, &output_offset))
1222 return output_offset != -1;
1225 // By default we assume that the address is mapped. This should
1226 // only be called after we have passed all sections to Layout. At
1227 // that point we should know what we are discarding.
1231 // Given an address OFFSET relative to the start of input section
1232 // SHNDX in object OBJECT, return the output offset relative to the
1233 // start of the section. This should only be called if SHNDX in
1234 // OBJECT has a special mapping.
1237 Output_section::output_offset(const Relobj* object, unsigned int shndx,
1240 gold_assert(object->is_section_specially_mapped(shndx));
1241 // This can only be called meaningfully when layout is complete.
1242 gold_assert(Output_data::is_layout_complete());
1244 for (Input_section_list::const_iterator p = this->input_sections_.begin();
1245 p != this->input_sections_.end();
1248 off_t output_offset;
1249 if (p->output_offset(object, shndx, offset, &output_offset))
1250 return output_offset;
1255 // Return the output virtual address of OFFSET relative to the start
1256 // of input section SHNDX in object OBJECT.
1259 Output_section::output_address(const Relobj* object, unsigned int shndx,
1262 gold_assert(object->is_section_specially_mapped(shndx));
1263 // This can only be called meaningfully when layout is complete.
1264 gold_assert(Output_data::is_layout_complete());
1266 uint64_t addr = this->address() + this->first_input_offset_;
1267 for (Input_section_list::const_iterator p = this->input_sections_.begin();
1268 p != this->input_sections_.end();
1271 addr = align_address(addr, p->addralign());
1272 off_t output_offset;
1273 if (p->output_offset(object, shndx, offset, &output_offset))
1275 if (output_offset == -1)
1277 return addr + output_offset;
1279 addr += p->data_size();
1282 // If we get here, it means that we don't know the mapping for this
1283 // input section. This might happen in principle if
1284 // add_input_section were called before add_output_section_data.
1285 // But it should never actually happen.
1290 // Set the address of an Output_section. This is where we handle
1291 // setting the addresses of any Output_section_data objects.
1294 Output_section::do_set_address(uint64_t address, off_t startoff)
1296 if (this->input_sections_.empty())
1299 off_t off = startoff + this->first_input_offset_;
1300 for (Input_section_list::iterator p = this->input_sections_.begin();
1301 p != this->input_sections_.end();
1304 off = align_address(off, p->addralign());
1305 p->set_address(address + (off - startoff), off, startoff);
1306 off += p->data_size();
1309 this->set_data_size(off - startoff);
1312 // Write the section header to *OSHDR.
1314 template<int size, bool big_endian>
1316 Output_section::write_header(const Layout* layout,
1317 const Stringpool* secnamepool,
1318 elfcpp::Shdr_write<size, big_endian>* oshdr) const
1320 oshdr->put_sh_name(secnamepool->get_offset(this->name_));
1321 oshdr->put_sh_type(this->type_);
1322 oshdr->put_sh_flags(this->flags_);
1323 oshdr->put_sh_addr(this->address());
1324 oshdr->put_sh_offset(this->offset());
1325 oshdr->put_sh_size(this->data_size());
1326 if (this->link_section_ != NULL)
1327 oshdr->put_sh_link(this->link_section_->out_shndx());
1328 else if (this->should_link_to_symtab_)
1329 oshdr->put_sh_link(layout->symtab_section()->out_shndx());
1330 else if (this->should_link_to_dynsym_)
1331 oshdr->put_sh_link(layout->dynsym_section()->out_shndx());
1333 oshdr->put_sh_link(this->link_);
1334 if (this->info_section_ != NULL)
1335 oshdr->put_sh_info(this->info_section_->out_shndx());
1337 oshdr->put_sh_info(this->info_);
1338 oshdr->put_sh_addralign(this->addralign_);
1339 oshdr->put_sh_entsize(this->entsize_);
1342 // Write out the data. For input sections the data is written out by
1343 // Object::relocate, but we have to handle Output_section_data objects
1347 Output_section::do_write(Output_file* of)
1349 off_t output_section_file_offset = this->offset();
1350 for (Fill_list::iterator p = this->fills_.begin();
1351 p != this->fills_.end();
1354 std::string fill_data(of->target()->code_fill(p->length()));
1355 of->write(output_section_file_offset + p->section_offset(),
1356 fill_data.data(), fill_data.size());
1359 for (Input_section_list::iterator p = this->input_sections_.begin();
1360 p != this->input_sections_.end();
1365 // Output segment methods.
1367 Output_segment::Output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
1378 is_align_known_(false)
1382 // Add an Output_section to an Output_segment.
1385 Output_segment::add_output_section(Output_section* os,
1386 elfcpp::Elf_Word seg_flags,
1389 gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
1390 gold_assert(!this->is_align_known_);
1392 // Update the segment flags.
1393 this->flags_ |= seg_flags;
1395 Output_segment::Output_data_list* pdl;
1396 if (os->type() == elfcpp::SHT_NOBITS)
1397 pdl = &this->output_bss_;
1399 pdl = &this->output_data_;
1401 // So that PT_NOTE segments will work correctly, we need to ensure
1402 // that all SHT_NOTE sections are adjacent. This will normally
1403 // happen automatically, because all the SHT_NOTE input sections
1404 // will wind up in the same output section. However, it is possible
1405 // for multiple SHT_NOTE input sections to have different section
1406 // flags, and thus be in different output sections, but for the
1407 // different section flags to map into the same segment flags and
1408 // thus the same output segment.
1410 // Note that while there may be many input sections in an output
1411 // section, there are normally only a few output sections in an
1412 // output segment. This loop is expected to be fast.
1414 if (os->type() == elfcpp::SHT_NOTE && !pdl->empty())
1416 Output_segment::Output_data_list::iterator p = pdl->end();
1420 if ((*p)->is_section_type(elfcpp::SHT_NOTE))
1422 // We don't worry about the FRONT parameter.
1428 while (p != pdl->begin());
1431 // Similarly, so that PT_TLS segments will work, we need to group
1432 // SHF_TLS sections. An SHF_TLS/SHT_NOBITS section is a special
1433 // case: we group the SHF_TLS/SHT_NOBITS sections right after the
1434 // SHF_TLS/SHT_PROGBITS sections. This lets us set up PT_TLS
1436 if ((os->flags() & elfcpp::SHF_TLS) != 0 && !this->output_data_.empty())
1438 pdl = &this->output_data_;
1439 bool nobits = os->type() == elfcpp::SHT_NOBITS;
1440 bool sawtls = false;
1441 Output_segment::Output_data_list::iterator p = pdl->end();
1446 if ((*p)->is_section_flag_set(elfcpp::SHF_TLS))
1449 // Put a NOBITS section after the first TLS section.
1450 // But a PROGBITS section after the first TLS/PROGBITS
1452 insert = nobits || !(*p)->is_section_type(elfcpp::SHT_NOBITS);
1456 // If we've gone past the TLS sections, but we've seen a
1457 // TLS section, then we need to insert this section now.
1463 // We don't worry about the FRONT parameter.
1469 while (p != pdl->begin());
1471 // There are no TLS sections yet; put this one at the requested
1472 // location in the section list.
1476 pdl->push_front(os);
1481 // Add an Output_data (which is not an Output_section) to the start of
1485 Output_segment::add_initial_output_data(Output_data* od)
1487 gold_assert(!this->is_align_known_);
1488 this->output_data_.push_front(od);
1491 // Return the maximum alignment of the Output_data in Output_segment.
1492 // Once we compute this, we prohibit new sections from being added.
1495 Output_segment::addralign()
1497 if (!this->is_align_known_)
1501 addralign = Output_segment::maximum_alignment(&this->output_data_);
1502 if (addralign > this->align_)
1503 this->align_ = addralign;
1505 addralign = Output_segment::maximum_alignment(&this->output_bss_);
1506 if (addralign > this->align_)
1507 this->align_ = addralign;
1509 this->is_align_known_ = true;
1512 return this->align_;
1515 // Return the maximum alignment of a list of Output_data.
1518 Output_segment::maximum_alignment(const Output_data_list* pdl)
1521 for (Output_data_list::const_iterator p = pdl->begin();
1525 uint64_t addralign = (*p)->addralign();
1526 if (addralign > ret)
1532 // Set the section addresses for an Output_segment. ADDR is the
1533 // address and *POFF is the file offset. Set the section indexes
1534 // starting with *PSHNDX. Return the address of the immediately
1535 // following segment. Update *POFF and *PSHNDX.
1538 Output_segment::set_section_addresses(uint64_t addr, off_t* poff,
1539 unsigned int* pshndx)
1541 gold_assert(this->type_ == elfcpp::PT_LOAD);
1543 this->vaddr_ = addr;
1544 this->paddr_ = addr;
1546 off_t orig_off = *poff;
1547 this->offset_ = orig_off;
1549 *poff = align_address(*poff, this->addralign());
1551 addr = this->set_section_list_addresses(&this->output_data_, addr, poff,
1553 this->filesz_ = *poff - orig_off;
1557 uint64_t ret = this->set_section_list_addresses(&this->output_bss_, addr,
1559 this->memsz_ = *poff - orig_off;
1561 // Ignore the file offset adjustments made by the BSS Output_data
1568 // Set the addresses and file offsets in a list of Output_data
1572 Output_segment::set_section_list_addresses(Output_data_list* pdl,
1573 uint64_t addr, off_t* poff,
1574 unsigned int* pshndx)
1576 off_t startoff = *poff;
1578 off_t off = startoff;
1579 for (Output_data_list::iterator p = pdl->begin();
1583 off = align_address(off, (*p)->addralign());
1584 (*p)->set_address(addr + (off - startoff), off);
1586 // Unless this is a PT_TLS segment, we want to ignore the size
1587 // of a SHF_TLS/SHT_NOBITS section. Such a section does not
1588 // affect the size of a PT_LOAD segment.
1589 if (this->type_ == elfcpp::PT_TLS
1590 || !(*p)->is_section_flag_set(elfcpp::SHF_TLS)
1591 || !(*p)->is_section_type(elfcpp::SHT_NOBITS))
1592 off += (*p)->data_size();
1594 if ((*p)->is_section())
1596 (*p)->set_out_shndx(*pshndx);
1602 return addr + (off - startoff);
1605 // For a non-PT_LOAD segment, set the offset from the sections, if
1609 Output_segment::set_offset()
1611 gold_assert(this->type_ != elfcpp::PT_LOAD);
1613 if (this->output_data_.empty() && this->output_bss_.empty())
1624 const Output_data* first;
1625 if (this->output_data_.empty())
1626 first = this->output_bss_.front();
1628 first = this->output_data_.front();
1629 this->vaddr_ = first->address();
1630 this->paddr_ = this->vaddr_;
1631 this->offset_ = first->offset();
1633 if (this->output_data_.empty())
1637 const Output_data* last_data = this->output_data_.back();
1638 this->filesz_ = (last_data->address()
1639 + last_data->data_size()
1643 const Output_data* last;
1644 if (this->output_bss_.empty())
1645 last = this->output_data_.back();
1647 last = this->output_bss_.back();
1648 this->memsz_ = (last->address()
1653 // Return the number of Output_sections in an Output_segment.
1656 Output_segment::output_section_count() const
1658 return (this->output_section_count_list(&this->output_data_)
1659 + this->output_section_count_list(&this->output_bss_));
1662 // Return the number of Output_sections in an Output_data_list.
1665 Output_segment::output_section_count_list(const Output_data_list* pdl) const
1667 unsigned int count = 0;
1668 for (Output_data_list::const_iterator p = pdl->begin();
1672 if ((*p)->is_section())
1678 // Write the segment data into *OPHDR.
1680 template<int size, bool big_endian>
1682 Output_segment::write_header(elfcpp::Phdr_write<size, big_endian>* ophdr)
1684 ophdr->put_p_type(this->type_);
1685 ophdr->put_p_offset(this->offset_);
1686 ophdr->put_p_vaddr(this->vaddr_);
1687 ophdr->put_p_paddr(this->paddr_);
1688 ophdr->put_p_filesz(this->filesz_);
1689 ophdr->put_p_memsz(this->memsz_);
1690 ophdr->put_p_flags(this->flags_);
1691 ophdr->put_p_align(this->addralign());
1694 // Write the section headers into V.
1696 template<int size, bool big_endian>
1698 Output_segment::write_section_headers(const Layout* layout,
1699 const Stringpool* secnamepool,
1701 unsigned int *pshndx
1702 ACCEPT_SIZE_ENDIAN) const
1704 // Every section that is attached to a segment must be attached to a
1705 // PT_LOAD segment, so we only write out section headers for PT_LOAD
1707 if (this->type_ != elfcpp::PT_LOAD)
1710 v = this->write_section_headers_list
1711 SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
1712 layout, secnamepool, &this->output_data_, v, pshndx
1713 SELECT_SIZE_ENDIAN(size, big_endian));
1714 v = this->write_section_headers_list
1715 SELECT_SIZE_ENDIAN_NAME(size, big_endian) (
1716 layout, secnamepool, &this->output_bss_, v, pshndx
1717 SELECT_SIZE_ENDIAN(size, big_endian));
1721 template<int size, bool big_endian>
1723 Output_segment::write_section_headers_list(const Layout* layout,
1724 const Stringpool* secnamepool,
1725 const Output_data_list* pdl,
1727 unsigned int* pshndx
1728 ACCEPT_SIZE_ENDIAN) const
1730 const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
1731 for (Output_data_list::const_iterator p = pdl->begin();
1735 if ((*p)->is_section())
1737 const Output_section* ps = static_cast<const Output_section*>(*p);
1738 gold_assert(*pshndx == ps->out_shndx());
1739 elfcpp::Shdr_write<size, big_endian> oshdr(v);
1740 ps->write_header(layout, secnamepool, &oshdr);
1748 // Output_file methods.
1750 Output_file::Output_file(const General_options& options, Target* target)
1751 : options_(options),
1753 name_(options.output_file_name()),
1760 // Open the output file.
1763 Output_file::open(off_t file_size)
1765 this->file_size_ = file_size;
1767 // Unlink the file first; otherwise the open() may fail if the file
1768 // is busy (e.g. it's an executable that's currently being executed).
1770 // However, the linker may be part of a system where a zero-length
1771 // file is created for it to write to, with tight permissions (gcc
1772 // 2.95 did something like this). Unlinking the file would work
1773 // around those permission controls, so we only unlink if the file
1774 // has a non-zero size. We also unlink only regular files to avoid
1775 // trouble with directories/etc.
1777 // If we fail, continue; this command is merely a best-effort attempt
1778 // to improve the odds for open().
1781 if (::stat(this->name_, &s) == 0 && s.st_size != 0)
1782 unlink_if_ordinary(this->name_);
1784 int mode = parameters->output_is_object() ? 0666 : 0777;
1785 int o = ::open(this->name_, O_RDWR | O_CREAT | O_TRUNC, mode);
1787 gold_fatal(_("%s: open: %s"), this->name_, strerror(errno));
1790 // Write out one byte to make the file the right size.
1791 if (::lseek(o, file_size - 1, SEEK_SET) < 0)
1792 gold_fatal(_("%s: lseek: %s"), this->name_, strerror(errno));
1794 if (::write(o, &b, 1) != 1)
1795 gold_fatal(_("%s: write: %s"), this->name_, strerror(errno));
1797 // Map the file into memory.
1798 void* base = ::mmap(NULL, file_size, PROT_READ | PROT_WRITE,
1800 if (base == MAP_FAILED)
1801 gold_fatal(_("%s: mmap: %s"), this->name_, strerror(errno));
1802 this->base_ = static_cast<unsigned char*>(base);
1805 // Close the output file.
1808 Output_file::close()
1810 if (::munmap(this->base_, this->file_size_) < 0)
1811 gold_error(_("%s: munmap: %s"), this->name_, strerror(errno));
1814 if (::close(this->o_) < 0)
1815 gold_error(_("%s: close: %s"), this->name_, strerror(errno));
1819 // Instantiate the templates we need. We could use the configure
1820 // script to restrict this to only the ones for implemented targets.
1822 #ifdef HAVE_TARGET_32_LITTLE
1825 Output_section::add_input_section<32, false>(
1826 Sized_relobj<32, false>* object,
1828 const char* secname,
1829 const elfcpp::Shdr<32, false>& shdr,
1830 unsigned int reloc_shndx);
1833 #ifdef HAVE_TARGET_32_BIG
1836 Output_section::add_input_section<32, true>(
1837 Sized_relobj<32, true>* object,
1839 const char* secname,
1840 const elfcpp::Shdr<32, true>& shdr,
1841 unsigned int reloc_shndx);
1844 #ifdef HAVE_TARGET_64_LITTLE
1847 Output_section::add_input_section<64, false>(
1848 Sized_relobj<64, false>* object,
1850 const char* secname,
1851 const elfcpp::Shdr<64, false>& shdr,
1852 unsigned int reloc_shndx);
1855 #ifdef HAVE_TARGET_64_BIG
1858 Output_section::add_input_section<64, true>(
1859 Sized_relobj<64, true>* object,
1861 const char* secname,
1862 const elfcpp::Shdr<64, true>& shdr,
1863 unsigned int reloc_shndx);
1866 #ifdef HAVE_TARGET_32_LITTLE
1868 class Output_data_reloc<elfcpp::SHT_REL, false, 32, false>;
1871 #ifdef HAVE_TARGET_32_BIG
1873 class Output_data_reloc<elfcpp::SHT_REL, false, 32, true>;
1876 #ifdef HAVE_TARGET_64_LITTLE
1878 class Output_data_reloc<elfcpp::SHT_REL, false, 64, false>;
1881 #ifdef HAVE_TARGET_64_BIG
1883 class Output_data_reloc<elfcpp::SHT_REL, false, 64, true>;
1886 #ifdef HAVE_TARGET_32_LITTLE
1888 class Output_data_reloc<elfcpp::SHT_REL, true, 32, false>;
1891 #ifdef HAVE_TARGET_32_BIG
1893 class Output_data_reloc<elfcpp::SHT_REL, true, 32, true>;
1896 #ifdef HAVE_TARGET_64_LITTLE
1898 class Output_data_reloc<elfcpp::SHT_REL, true, 64, false>;
1901 #ifdef HAVE_TARGET_64_BIG
1903 class Output_data_reloc<elfcpp::SHT_REL, true, 64, true>;
1906 #ifdef HAVE_TARGET_32_LITTLE
1908 class Output_data_reloc<elfcpp::SHT_RELA, false, 32, false>;
1911 #ifdef HAVE_TARGET_32_BIG
1913 class Output_data_reloc<elfcpp::SHT_RELA, false, 32, true>;
1916 #ifdef HAVE_TARGET_64_LITTLE
1918 class Output_data_reloc<elfcpp::SHT_RELA, false, 64, false>;
1921 #ifdef HAVE_TARGET_64_BIG
1923 class Output_data_reloc<elfcpp::SHT_RELA, false, 64, true>;
1926 #ifdef HAVE_TARGET_32_LITTLE
1928 class Output_data_reloc<elfcpp::SHT_RELA, true, 32, false>;
1931 #ifdef HAVE_TARGET_32_BIG
1933 class Output_data_reloc<elfcpp::SHT_RELA, true, 32, true>;
1936 #ifdef HAVE_TARGET_64_LITTLE
1938 class Output_data_reloc<elfcpp::SHT_RELA, true, 64, false>;
1941 #ifdef HAVE_TARGET_64_BIG
1943 class Output_data_reloc<elfcpp::SHT_RELA, true, 64, true>;
1946 #ifdef HAVE_TARGET_32_LITTLE
1948 class Output_data_got<32, false>;
1951 #ifdef HAVE_TARGET_32_BIG
1953 class Output_data_got<32, true>;
1956 #ifdef HAVE_TARGET_64_LITTLE
1958 class Output_data_got<64, false>;
1961 #ifdef HAVE_TARGET_64_BIG
1963 class Output_data_got<64, true>;
1966 } // End namespace gold.