1 // layout.cc -- lay out output file sections for gold
3 // Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
32 #include "libiberty.h"
36 #include "parameters.h"
40 #include "script-sections.h"
45 #include "compressed_output.h"
46 #include "reduced_debug_output.h"
48 #include "descriptors.h"
50 #include "incremental.h"
56 // Layout_task_runner methods.
58 // Lay out the sections. This is called after all the input objects
62 Layout_task_runner::run(Workqueue* workqueue, const Task* task)
64 off_t file_size = this->layout_->finalize(this->input_objects_,
69 // Now we know the final size of the output file and we know where
70 // each piece of information goes.
72 if (this->mapfile_ != NULL)
74 this->mapfile_->print_discarded_sections(this->input_objects_);
75 this->layout_->print_to_mapfile(this->mapfile_);
78 Output_file* of = new Output_file(parameters->options().output_file_name());
79 if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
80 of->set_is_temporary();
83 // Queue up the final set of tasks.
84 gold::queue_final_tasks(this->options_, this->input_objects_,
85 this->symtab_, this->layout_, workqueue, of);
90 Layout::Layout(int number_of_input_files, Script_options* script_options)
91 : number_of_input_files_(number_of_input_files),
92 script_options_(script_options),
100 unattached_section_list_(),
101 special_output_list_(),
102 section_headers_(NULL),
104 relro_segment_(NULL),
105 symtab_section_(NULL),
106 symtab_xindex_(NULL),
107 dynsym_section_(NULL),
108 dynsym_xindex_(NULL),
109 dynamic_section_(NULL),
111 eh_frame_section_(NULL),
112 eh_frame_data_(NULL),
113 added_eh_frame_data_(false),
114 eh_frame_hdr_section_(NULL),
115 build_id_note_(NULL),
119 output_file_size_(-1),
120 sections_are_attached_(false),
121 input_requires_executable_stack_(false),
122 input_with_gnu_stack_note_(false),
123 input_without_gnu_stack_note_(false),
124 has_static_tls_(false),
125 any_postprocessing_sections_(false),
126 resized_signatures_(false),
127 incremental_inputs_(NULL)
129 // Make space for more than enough segments for a typical file.
130 // This is just for efficiency--it's OK if we wind up needing more.
131 this->segment_list_.reserve(12);
133 // We expect two unattached Output_data objects: the file header and
134 // the segment headers.
135 this->special_output_list_.reserve(2);
137 // Initialize structure needed for an incremental build.
138 if (parameters->options().incremental())
139 this->incremental_inputs_ = new Incremental_inputs;
142 // Hash a key we use to look up an output section mapping.
145 Layout::Hash_key::operator()(const Layout::Key& k) const
147 return k.first + k.second.first + k.second.second;
150 // Returns whether the given section is in the list of
151 // debug-sections-used-by-some-version-of-gdb. Currently,
152 // we've checked versions of gdb up to and including 6.7.1.
154 static const char* gdb_sections[] =
156 // ".debug_aranges", // not used by gdb as of 6.7.1
162 // ".debug_pubnames", // not used by gdb as of 6.7.1
167 static const char* lines_only_debug_sections[] =
169 // ".debug_aranges", // not used by gdb as of 6.7.1
175 // ".debug_pubnames", // not used by gdb as of 6.7.1
181 is_gdb_debug_section(const char* str)
183 // We can do this faster: binary search or a hashtable. But why bother?
184 for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
185 if (strcmp(str, gdb_sections[i]) == 0)
191 is_lines_only_debug_section(const char* str)
193 // We can do this faster: binary search or a hashtable. But why bother?
195 i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections);
197 if (strcmp(str, lines_only_debug_sections[i]) == 0)
202 // Whether to include this section in the link.
204 template<int size, bool big_endian>
206 Layout::include_section(Sized_relobj<size, big_endian>*, const char* name,
207 const elfcpp::Shdr<size, big_endian>& shdr)
209 if (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE)
212 switch (shdr.get_sh_type())
214 case elfcpp::SHT_NULL:
215 case elfcpp::SHT_SYMTAB:
216 case elfcpp::SHT_DYNSYM:
217 case elfcpp::SHT_HASH:
218 case elfcpp::SHT_DYNAMIC:
219 case elfcpp::SHT_SYMTAB_SHNDX:
222 case elfcpp::SHT_STRTAB:
223 // Discard the sections which have special meanings in the ELF
224 // ABI. Keep others (e.g., .stabstr). We could also do this by
225 // checking the sh_link fields of the appropriate sections.
226 return (strcmp(name, ".dynstr") != 0
227 && strcmp(name, ".strtab") != 0
228 && strcmp(name, ".shstrtab") != 0);
230 case elfcpp::SHT_RELA:
231 case elfcpp::SHT_REL:
232 case elfcpp::SHT_GROUP:
233 // If we are emitting relocations these should be handled
235 gold_assert(!parameters->options().relocatable()
236 && !parameters->options().emit_relocs());
239 case elfcpp::SHT_PROGBITS:
240 if (parameters->options().strip_debug()
241 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
243 if (is_debug_info_section(name))
246 if (parameters->options().strip_debug_non_line()
247 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
249 // Debugging sections can only be recognized by name.
250 if (is_prefix_of(".debug", name)
251 && !is_lines_only_debug_section(name))
254 if (parameters->options().strip_debug_gdb()
255 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
257 // Debugging sections can only be recognized by name.
258 if (is_prefix_of(".debug", name)
259 && !is_gdb_debug_section(name))
262 if (parameters->options().strip_lto_sections()
263 && !parameters->options().relocatable()
264 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
266 // Ignore LTO sections containing intermediate code.
267 if (is_prefix_of(".gnu.lto_", name))
277 // Return an output section named NAME, or NULL if there is none.
280 Layout::find_output_section(const char* name) const
282 for (Section_list::const_iterator p = this->section_list_.begin();
283 p != this->section_list_.end();
285 if (strcmp((*p)->name(), name) == 0)
290 // Return an output segment of type TYPE, with segment flags SET set
291 // and segment flags CLEAR clear. Return NULL if there is none.
294 Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
295 elfcpp::Elf_Word clear) const
297 for (Segment_list::const_iterator p = this->segment_list_.begin();
298 p != this->segment_list_.end();
300 if (static_cast<elfcpp::PT>((*p)->type()) == type
301 && ((*p)->flags() & set) == set
302 && ((*p)->flags() & clear) == 0)
307 // Return the output section to use for section NAME with type TYPE
308 // and section flags FLAGS. NAME must be canonicalized in the string
309 // pool, and NAME_KEY is the key.
312 Layout::get_output_section(const char* name, Stringpool::Key name_key,
313 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags)
315 elfcpp::Elf_Xword lookup_flags = flags;
317 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
318 // read-write with read-only sections. Some other ELF linkers do
319 // not do this. FIXME: Perhaps there should be an option
321 lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
323 const Key key(name_key, std::make_pair(type, lookup_flags));
324 const std::pair<Key, Output_section*> v(key, NULL);
325 std::pair<Section_name_map::iterator, bool> ins(
326 this->section_name_map_.insert(v));
329 return ins.first->second;
332 // This is the first time we've seen this name/type/flags
333 // combination. For compatibility with the GNU linker, we
334 // combine sections with contents and zero flags with sections
335 // with non-zero flags. This is a workaround for cases where
336 // assembler code forgets to set section flags. FIXME: Perhaps
337 // there should be an option to control this.
338 Output_section* os = NULL;
340 if (type == elfcpp::SHT_PROGBITS)
344 Output_section* same_name = this->find_output_section(name);
345 if (same_name != NULL
346 && same_name->type() == elfcpp::SHT_PROGBITS
347 && (same_name->flags() & elfcpp::SHF_TLS) == 0)
350 else if ((flags & elfcpp::SHF_TLS) == 0)
352 elfcpp::Elf_Xword zero_flags = 0;
353 const Key zero_key(name_key, std::make_pair(type, zero_flags));
354 Section_name_map::iterator p =
355 this->section_name_map_.find(zero_key);
356 if (p != this->section_name_map_.end())
362 os = this->make_output_section(name, type, flags);
363 ins.first->second = os;
368 // Pick the output section to use for section NAME, in input file
369 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
370 // linker created section. IS_INPUT_SECTION is true if we are
371 // choosing an output section for an input section found in a input
372 // file. This will return NULL if the input section should be
376 Layout::choose_output_section(const Relobj* relobj, const char* name,
377 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
378 bool is_input_section)
380 // We should not see any input sections after we have attached
381 // sections to segments.
382 gold_assert(!is_input_section || !this->sections_are_attached_);
384 // Some flags in the input section should not be automatically
385 // copied to the output section.
386 flags &= ~ (elfcpp::SHF_INFO_LINK
387 | elfcpp::SHF_LINK_ORDER
390 | elfcpp::SHF_STRINGS);
392 if (this->script_options_->saw_sections_clause())
394 // We are using a SECTIONS clause, so the output section is
395 // chosen based only on the name.
397 Script_sections* ss = this->script_options_->script_sections();
398 const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
399 Output_section** output_section_slot;
400 name = ss->output_section_name(file_name, name, &output_section_slot);
403 // The SECTIONS clause says to discard this input section.
407 // If this is an orphan section--one not mentioned in the linker
408 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
409 // default processing below.
411 if (output_section_slot != NULL)
413 if (*output_section_slot != NULL)
414 return *output_section_slot;
416 // We don't put sections found in the linker script into
417 // SECTION_NAME_MAP_. That keeps us from getting confused
418 // if an orphan section is mapped to a section with the same
419 // name as one in the linker script.
421 name = this->namepool_.add(name, false, NULL);
423 Output_section* os = this->make_output_section(name, type, flags);
424 os->set_found_in_sections_clause();
425 *output_section_slot = os;
430 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
432 // Turn NAME from the name of the input section into the name of the
435 size_t len = strlen(name);
437 && !this->script_options_->saw_sections_clause()
438 && !parameters->options().relocatable())
439 name = Layout::output_section_name(name, &len);
441 Stringpool::Key name_key;
442 name = this->namepool_.add_with_length(name, len, true, &name_key);
444 // Find or make the output section. The output section is selected
445 // based on the section name, type, and flags.
446 return this->get_output_section(name, name_key, type, flags);
449 // Return the output section to use for input section SHNDX, with name
450 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
451 // index of a relocation section which applies to this section, or 0
452 // if none, or -1U if more than one. RELOC_TYPE is the type of the
453 // relocation section if there is one. Set *OFF to the offset of this
454 // input section without the output section. Return NULL if the
455 // section should be discarded. Set *OFF to -1 if the section
456 // contents should not be written directly to the output file, but
457 // will instead receive special handling.
459 template<int size, bool big_endian>
461 Layout::layout(Sized_relobj<size, big_endian>* object, unsigned int shndx,
462 const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
463 unsigned int reloc_shndx, unsigned int, off_t* off)
467 if (!this->include_section(object, name, shdr))
472 // In a relocatable link a grouped section must not be combined with
473 // any other sections.
474 if (parameters->options().relocatable()
475 && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
477 name = this->namepool_.add(name, true, NULL);
478 os = this->make_output_section(name, shdr.get_sh_type(),
479 shdr.get_sh_flags());
483 os = this->choose_output_section(object, name, shdr.get_sh_type(),
484 shdr.get_sh_flags(), true);
489 // By default the GNU linker sorts input sections whose names match
490 // .ctor.*, .dtor.*, .init_array.*, or .fini_array.*. The sections
491 // are sorted by name. This is used to implement constructor
492 // priority ordering. We are compatible.
493 if (!this->script_options_->saw_sections_clause()
494 && (is_prefix_of(".ctors.", name)
495 || is_prefix_of(".dtors.", name)
496 || is_prefix_of(".init_array.", name)
497 || is_prefix_of(".fini_array.", name)))
498 os->set_must_sort_attached_input_sections();
500 // FIXME: Handle SHF_LINK_ORDER somewhere.
502 *off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
503 this->script_options_->saw_sections_clause());
508 // Handle a relocation section when doing a relocatable link.
510 template<int size, bool big_endian>
512 Layout::layout_reloc(Sized_relobj<size, big_endian>* object,
514 const elfcpp::Shdr<size, big_endian>& shdr,
515 Output_section* data_section,
516 Relocatable_relocs* rr)
518 gold_assert(parameters->options().relocatable()
519 || parameters->options().emit_relocs());
521 int sh_type = shdr.get_sh_type();
524 if (sh_type == elfcpp::SHT_REL)
526 else if (sh_type == elfcpp::SHT_RELA)
530 name += data_section->name();
532 Output_section* os = this->choose_output_section(object, name.c_str(),
537 os->set_should_link_to_symtab();
538 os->set_info_section(data_section);
540 Output_section_data* posd;
541 if (sh_type == elfcpp::SHT_REL)
543 os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
544 posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
548 else if (sh_type == elfcpp::SHT_RELA)
550 os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
551 posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
558 os->add_output_section_data(posd);
559 rr->set_output_data(posd);
564 // Handle a group section when doing a relocatable link.
566 template<int size, bool big_endian>
568 Layout::layout_group(Symbol_table* symtab,
569 Sized_relobj<size, big_endian>* object,
571 const char* group_section_name,
572 const char* signature,
573 const elfcpp::Shdr<size, big_endian>& shdr,
574 elfcpp::Elf_Word flags,
575 std::vector<unsigned int>* shndxes)
577 gold_assert(parameters->options().relocatable());
578 gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
579 group_section_name = this->namepool_.add(group_section_name, true, NULL);
580 Output_section* os = this->make_output_section(group_section_name,
582 shdr.get_sh_flags());
584 // We need to find a symbol with the signature in the symbol table.
585 // If we don't find one now, we need to look again later.
586 Symbol* sym = symtab->lookup(signature, NULL);
588 os->set_info_symndx(sym);
591 // Reserve some space to minimize reallocations.
592 if (this->group_signatures_.empty())
593 this->group_signatures_.reserve(this->number_of_input_files_ * 16);
595 // We will wind up using a symbol whose name is the signature.
596 // So just put the signature in the symbol name pool to save it.
597 signature = symtab->canonicalize_name(signature);
598 this->group_signatures_.push_back(Group_signature(os, signature));
601 os->set_should_link_to_symtab();
604 section_size_type entry_count =
605 convert_to_section_size_type(shdr.get_sh_size() / 4);
606 Output_section_data* posd =
607 new Output_data_group<size, big_endian>(object, entry_count, flags,
609 os->add_output_section_data(posd);
612 // Special GNU handling of sections name .eh_frame. They will
613 // normally hold exception frame data as defined by the C++ ABI
614 // (http://codesourcery.com/cxx-abi/).
616 template<int size, bool big_endian>
618 Layout::layout_eh_frame(Sized_relobj<size, big_endian>* object,
619 const unsigned char* symbols,
621 const unsigned char* symbol_names,
622 off_t symbol_names_size,
624 const elfcpp::Shdr<size, big_endian>& shdr,
625 unsigned int reloc_shndx, unsigned int reloc_type,
628 gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS);
629 gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
631 const char* const name = ".eh_frame";
632 Output_section* os = this->choose_output_section(object,
634 elfcpp::SHT_PROGBITS,
640 if (this->eh_frame_section_ == NULL)
642 this->eh_frame_section_ = os;
643 this->eh_frame_data_ = new Eh_frame();
645 if (parameters->options().eh_frame_hdr())
647 Output_section* hdr_os =
648 this->choose_output_section(NULL,
650 elfcpp::SHT_PROGBITS,
656 Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
657 this->eh_frame_data_);
658 hdr_os->add_output_section_data(hdr_posd);
660 hdr_os->set_after_input_sections();
662 if (!this->script_options_->saw_phdrs_clause())
664 Output_segment* hdr_oseg;
665 hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
667 hdr_oseg->add_output_section(hdr_os, elfcpp::PF_R);
670 this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
675 gold_assert(this->eh_frame_section_ == os);
677 if (this->eh_frame_data_->add_ehframe_input_section(object,
686 os->update_flags_for_input_section(shdr.get_sh_flags());
688 // We found a .eh_frame section we are going to optimize, so now
689 // we can add the set of optimized sections to the output
690 // section. We need to postpone adding this until we've found a
691 // section we can optimize so that the .eh_frame section in
692 // crtbegin.o winds up at the start of the output section.
693 if (!this->added_eh_frame_data_)
695 os->add_output_section_data(this->eh_frame_data_);
696 this->added_eh_frame_data_ = true;
702 // We couldn't handle this .eh_frame section for some reason.
703 // Add it as a normal section.
704 bool saw_sections_clause = this->script_options_->saw_sections_clause();
705 *off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
706 saw_sections_clause);
712 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
713 // the output section.
716 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
717 elfcpp::Elf_Xword flags,
718 Output_section_data* posd)
720 Output_section* os = this->choose_output_section(NULL, name, type, flags,
723 os->add_output_section_data(posd);
727 // Map section flags to segment flags.
730 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
732 elfcpp::Elf_Word ret = elfcpp::PF_R;
733 if ((flags & elfcpp::SHF_WRITE) != 0)
735 if ((flags & elfcpp::SHF_EXECINSTR) != 0)
740 // Sometimes we compress sections. This is typically done for
741 // sections that are not part of normal program execution (such as
742 // .debug_* sections), and where the readers of these sections know
743 // how to deal with compressed sections. (To make it easier for them,
744 // we will rename the ouput section in such cases from .foo to
745 // .foo.zlib.nnnn, where nnnn is the uncompressed size.) This routine
746 // doesn't say for certain whether we'll compress -- it depends on
747 // commandline options as well -- just whether this section is a
748 // candidate for compression.
751 is_compressible_debug_section(const char* secname)
753 return (strncmp(secname, ".debug", sizeof(".debug") - 1) == 0);
756 // Make a new Output_section, and attach it to segments as
760 Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
761 elfcpp::Elf_Xword flags)
764 if ((flags & elfcpp::SHF_ALLOC) == 0
765 && strcmp(parameters->options().compress_debug_sections(), "none") != 0
766 && is_compressible_debug_section(name))
767 os = new Output_compressed_section(¶meters->options(), name, type,
770 else if ((flags & elfcpp::SHF_ALLOC) == 0
771 && parameters->options().strip_debug_non_line()
772 && strcmp(".debug_abbrev", name) == 0)
774 os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
776 if (this->debug_info_)
777 this->debug_info_->set_abbreviations(this->debug_abbrev_);
779 else if ((flags & elfcpp::SHF_ALLOC) == 0
780 && parameters->options().strip_debug_non_line()
781 && strcmp(".debug_info", name) == 0)
783 os = this->debug_info_ = new Output_reduced_debug_info_section(
785 if (this->debug_abbrev_)
786 this->debug_info_->set_abbreviations(this->debug_abbrev_);
789 os = new Output_section(name, type, flags);
791 parameters->target().new_output_section(os);
793 this->section_list_.push_back(os);
795 // The GNU linker by default sorts some sections by priority, so we
796 // do the same. We need to know that this might happen before we
797 // attach any input sections.
798 if (!this->script_options_->saw_sections_clause()
799 && (strcmp(name, ".ctors") == 0
800 || strcmp(name, ".dtors") == 0
801 || strcmp(name, ".init_array") == 0
802 || strcmp(name, ".fini_array") == 0))
803 os->set_may_sort_attached_input_sections();
805 // With -z relro, we have to recognize the special sections by name.
806 // There is no other way.
807 if (!this->script_options_->saw_sections_clause()
808 && parameters->options().relro()
809 && type == elfcpp::SHT_PROGBITS
810 && (flags & elfcpp::SHF_ALLOC) != 0
811 && (flags & elfcpp::SHF_WRITE) != 0)
813 if (strcmp(name, ".data.rel.ro") == 0)
815 else if (strcmp(name, ".data.rel.ro.local") == 0)
818 os->set_is_relro_local();
822 // If we have already attached the sections to segments, then we
823 // need to attach this one now. This happens for sections created
824 // directly by the linker.
825 if (this->sections_are_attached_)
826 this->attach_section_to_segment(os);
831 // Attach output sections to segments. This is called after we have
832 // seen all the input sections.
835 Layout::attach_sections_to_segments()
837 for (Section_list::iterator p = this->section_list_.begin();
838 p != this->section_list_.end();
840 this->attach_section_to_segment(*p);
842 this->sections_are_attached_ = true;
845 // Attach an output section to a segment.
848 Layout::attach_section_to_segment(Output_section* os)
850 if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
851 this->unattached_section_list_.push_back(os);
853 this->attach_allocated_section_to_segment(os);
856 // Attach an allocated output section to a segment.
859 Layout::attach_allocated_section_to_segment(Output_section* os)
861 elfcpp::Elf_Xword flags = os->flags();
862 gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
864 if (parameters->options().relocatable())
867 // If we have a SECTIONS clause, we can't handle the attachment to
868 // segments until after we've seen all the sections.
869 if (this->script_options_->saw_sections_clause())
872 gold_assert(!this->script_options_->saw_phdrs_clause());
874 // This output section goes into a PT_LOAD segment.
876 elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
878 // In general the only thing we really care about for PT_LOAD
879 // segments is whether or not they are writable, so that is how we
880 // search for them. Large data sections also go into their own
881 // PT_LOAD segment. People who need segments sorted on some other
882 // basis will have to use a linker script.
884 Segment_list::const_iterator p;
885 for (p = this->segment_list_.begin();
886 p != this->segment_list_.end();
889 if ((*p)->type() != elfcpp::PT_LOAD)
891 if (!parameters->options().omagic()
892 && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
894 // If -Tbss was specified, we need to separate the data and BSS
896 if (parameters->options().user_set_Tbss())
898 if ((os->type() == elfcpp::SHT_NOBITS)
899 == (*p)->has_any_data_sections())
902 if (os->is_large_data_section() && !(*p)->is_large_data_segment())
905 (*p)->add_output_section(os, seg_flags);
909 if (p == this->segment_list_.end())
911 Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
913 if (os->is_large_data_section())
914 oseg->set_is_large_data_segment();
915 oseg->add_output_section(os, seg_flags);
918 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
920 if (os->type() == elfcpp::SHT_NOTE)
922 // See if we already have an equivalent PT_NOTE segment.
923 for (p = this->segment_list_.begin();
924 p != segment_list_.end();
927 if ((*p)->type() == elfcpp::PT_NOTE
928 && (((*p)->flags() & elfcpp::PF_W)
929 == (seg_flags & elfcpp::PF_W)))
931 (*p)->add_output_section(os, seg_flags);
936 if (p == this->segment_list_.end())
938 Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
940 oseg->add_output_section(os, seg_flags);
944 // If we see a loadable SHF_TLS section, we create a PT_TLS
945 // segment. There can only be one such segment.
946 if ((flags & elfcpp::SHF_TLS) != 0)
948 if (this->tls_segment_ == NULL)
949 this->make_output_segment(elfcpp::PT_TLS, seg_flags);
950 this->tls_segment_->add_output_section(os, seg_flags);
953 // If -z relro is in effect, and we see a relro section, we create a
954 // PT_GNU_RELRO segment. There can only be one such segment.
955 if (os->is_relro() && parameters->options().relro())
957 gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
958 if (this->relro_segment_ == NULL)
959 this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
960 this->relro_segment_->add_output_section(os, seg_flags);
964 // Make an output section for a script.
967 Layout::make_output_section_for_script(const char* name)
969 name = this->namepool_.add(name, false, NULL);
970 Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
972 os->set_found_in_sections_clause();
976 // Return the number of segments we expect to see.
979 Layout::expected_segment_count() const
981 size_t ret = this->segment_list_.size();
983 // If we didn't see a SECTIONS clause in a linker script, we should
984 // already have the complete list of segments. Otherwise we ask the
985 // SECTIONS clause how many segments it expects, and add in the ones
986 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
988 if (!this->script_options_->saw_sections_clause())
992 const Script_sections* ss = this->script_options_->script_sections();
993 return ret + ss->expected_segment_count(this);
997 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
998 // is whether we saw a .note.GNU-stack section in the object file.
999 // GNU_STACK_FLAGS is the section flags. The flags give the
1000 // protection required for stack memory. We record this in an
1001 // executable as a PT_GNU_STACK segment. If an object file does not
1002 // have a .note.GNU-stack segment, we must assume that it is an old
1003 // object. On some targets that will force an executable stack.
1006 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags)
1008 if (!seen_gnu_stack)
1009 this->input_without_gnu_stack_note_ = true;
1012 this->input_with_gnu_stack_note_ = true;
1013 if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
1014 this->input_requires_executable_stack_ = true;
1018 // Create the dynamic sections which are needed before we read the
1022 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
1024 if (parameters->doing_static_link())
1027 this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
1028 elfcpp::SHT_DYNAMIC,
1030 | elfcpp::SHF_WRITE),
1032 this->dynamic_section_->set_is_relro();
1034 symtab->define_in_output_data("_DYNAMIC", NULL, this->dynamic_section_, 0, 0,
1035 elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
1036 elfcpp::STV_HIDDEN, 0, false, false);
1038 this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_);
1040 this->dynamic_section_->add_output_section_data(this->dynamic_data_);
1043 // For each output section whose name can be represented as C symbol,
1044 // define __start and __stop symbols for the section. This is a GNU
1048 Layout::define_section_symbols(Symbol_table* symtab)
1050 for (Section_list::const_iterator p = this->section_list_.begin();
1051 p != this->section_list_.end();
1054 const char* const name = (*p)->name();
1055 if (name[strspn(name,
1057 "ABCDEFGHIJKLMNOPWRSTUVWXYZ"
1058 "abcdefghijklmnopqrstuvwxyz"
1062 const std::string name_string(name);
1063 const std::string start_name("__start_" + name_string);
1064 const std::string stop_name("__stop_" + name_string);
1066 symtab->define_in_output_data(start_name.c_str(),
1073 elfcpp::STV_DEFAULT,
1075 false, // offset_is_from_end
1076 true); // only_if_ref
1078 symtab->define_in_output_data(stop_name.c_str(),
1085 elfcpp::STV_DEFAULT,
1087 true, // offset_is_from_end
1088 true); // only_if_ref
1093 // Define symbols for group signatures.
1096 Layout::define_group_signatures(Symbol_table* symtab)
1098 for (Group_signatures::iterator p = this->group_signatures_.begin();
1099 p != this->group_signatures_.end();
1102 Symbol* sym = symtab->lookup(p->signature, NULL);
1104 p->section->set_info_symndx(sym);
1107 // Force the name of the group section to the group
1108 // signature, and use the group's section symbol as the
1109 // signature symbol.
1110 if (strcmp(p->section->name(), p->signature) != 0)
1112 const char* name = this->namepool_.add(p->signature,
1114 p->section->set_name(name);
1116 p->section->set_needs_symtab_index();
1117 p->section->set_info_section_symndx(p->section);
1121 this->group_signatures_.clear();
1124 // Find the first read-only PT_LOAD segment, creating one if
1128 Layout::find_first_load_seg()
1130 for (Segment_list::const_iterator p = this->segment_list_.begin();
1131 p != this->segment_list_.end();
1134 if ((*p)->type() == elfcpp::PT_LOAD
1135 && ((*p)->flags() & elfcpp::PF_R) != 0
1136 && (parameters->options().omagic()
1137 || ((*p)->flags() & elfcpp::PF_W) == 0))
1141 gold_assert(!this->script_options_->saw_phdrs_clause());
1143 Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
1148 // Finalize the layout. When this is called, we have created all the
1149 // output sections and all the output segments which are based on
1150 // input sections. We have several things to do, and we have to do
1151 // them in the right order, so that we get the right results correctly
1154 // 1) Finalize the list of output segments and create the segment
1157 // 2) Finalize the dynamic symbol table and associated sections.
1159 // 3) Determine the final file offset of all the output segments.
1161 // 4) Determine the final file offset of all the SHF_ALLOC output
1164 // 5) Create the symbol table sections and the section name table
1167 // 6) Finalize the symbol table: set symbol values to their final
1168 // value and make a final determination of which symbols are going
1169 // into the output symbol table.
1171 // 7) Create the section table header.
1173 // 8) Determine the final file offset of all the output sections which
1174 // are not SHF_ALLOC, including the section table header.
1176 // 9) Finalize the ELF file header.
1178 // This function returns the size of the output file.
1181 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
1182 Target* target, const Task* task)
1184 target->finalize_sections(this);
1186 this->count_local_symbols(task, input_objects);
1188 this->create_gold_note();
1189 this->create_executable_stack_info(target);
1190 this->create_build_id();
1192 Output_segment* phdr_seg = NULL;
1193 if (!parameters->options().relocatable() && !parameters->doing_static_link())
1195 // There was a dynamic object in the link. We need to create
1196 // some information for the dynamic linker.
1198 // Create the PT_PHDR segment which will hold the program
1200 if (!this->script_options_->saw_phdrs_clause())
1201 phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
1203 // Create the dynamic symbol table, including the hash table.
1204 Output_section* dynstr;
1205 std::vector<Symbol*> dynamic_symbols;
1206 unsigned int local_dynamic_count;
1207 Versions versions(*this->script_options()->version_script_info(),
1209 this->create_dynamic_symtab(input_objects, symtab, &dynstr,
1210 &local_dynamic_count, &dynamic_symbols,
1213 // Create the .interp section to hold the name of the
1214 // interpreter, and put it in a PT_INTERP segment.
1215 if (!parameters->options().shared())
1216 this->create_interp(target);
1218 // Finish the .dynamic section to hold the dynamic data, and put
1219 // it in a PT_DYNAMIC segment.
1220 this->finish_dynamic_section(input_objects, symtab);
1222 // We should have added everything we need to the dynamic string
1224 this->dynpool_.set_string_offsets();
1226 // Create the version sections. We can't do this until the
1227 // dynamic string table is complete.
1228 this->create_version_sections(&versions, symtab, local_dynamic_count,
1229 dynamic_symbols, dynstr);
1232 if (this->incremental_inputs_)
1234 this->incremental_inputs_->finalize();
1235 this->create_incremental_info_sections();
1238 // If there is a SECTIONS clause, put all the input sections into
1239 // the required order.
1240 Output_segment* load_seg;
1241 if (this->script_options_->saw_sections_clause())
1242 load_seg = this->set_section_addresses_from_script(symtab);
1243 else if (parameters->options().relocatable())
1246 load_seg = this->find_first_load_seg();
1248 if (parameters->options().oformat_enum()
1249 != General_options::OBJECT_FORMAT_ELF)
1252 gold_assert(phdr_seg == NULL || load_seg != NULL);
1254 // Lay out the segment headers.
1255 Output_segment_headers* segment_headers;
1256 if (parameters->options().relocatable())
1257 segment_headers = NULL;
1260 segment_headers = new Output_segment_headers(this->segment_list_);
1261 if (load_seg != NULL)
1262 load_seg->add_initial_output_data(segment_headers);
1263 if (phdr_seg != NULL)
1264 phdr_seg->add_initial_output_data(segment_headers);
1267 // Lay out the file header.
1268 Output_file_header* file_header;
1269 file_header = new Output_file_header(target, symtab, segment_headers,
1270 parameters->options().entry());
1271 if (load_seg != NULL)
1272 load_seg->add_initial_output_data(file_header);
1274 this->special_output_list_.push_back(file_header);
1275 if (segment_headers != NULL)
1276 this->special_output_list_.push_back(segment_headers);
1278 if (this->script_options_->saw_phdrs_clause()
1279 && !parameters->options().relocatable())
1281 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
1282 // clause in a linker script.
1283 Script_sections* ss = this->script_options_->script_sections();
1284 ss->put_headers_in_phdrs(file_header, segment_headers);
1287 // We set the output section indexes in set_segment_offsets and
1288 // set_section_indexes.
1289 unsigned int shndx = 1;
1291 // Set the file offsets of all the segments, and all the sections
1294 if (!parameters->options().relocatable())
1295 off = this->set_segment_offsets(target, load_seg, &shndx);
1297 off = this->set_relocatable_section_offsets(file_header, &shndx);
1299 // Set the file offsets of all the non-data sections we've seen so
1300 // far which don't have to wait for the input sections. We need
1301 // this in order to finalize local symbols in non-allocated
1303 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1305 // Set the section indexes of all unallocated sections seen so far,
1306 // in case any of them are somehow referenced by a symbol.
1307 shndx = this->set_section_indexes(shndx);
1309 // Create the symbol table sections.
1310 this->create_symtab_sections(input_objects, symtab, shndx, &off);
1311 if (!parameters->doing_static_link())
1312 this->assign_local_dynsym_offsets(input_objects);
1314 // Process any symbol assignments from a linker script. This must
1315 // be called after the symbol table has been finalized.
1316 this->script_options_->finalize_symbols(symtab, this);
1318 // Create the .shstrtab section.
1319 Output_section* shstrtab_section = this->create_shstrtab();
1321 // Set the file offsets of the rest of the non-data sections which
1322 // don't have to wait for the input sections.
1323 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1325 // Now that all sections have been created, set the section indexes
1326 // for any sections which haven't been done yet.
1327 shndx = this->set_section_indexes(shndx);
1329 // Create the section table header.
1330 this->create_shdrs(shstrtab_section, &off);
1332 // If there are no sections which require postprocessing, we can
1333 // handle the section names now, and avoid a resize later.
1334 if (!this->any_postprocessing_sections_)
1335 off = this->set_section_offsets(off,
1336 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
1338 file_header->set_section_info(this->section_headers_, shstrtab_section);
1340 // Now we know exactly where everything goes in the output file
1341 // (except for non-allocated sections which require postprocessing).
1342 Output_data::layout_complete();
1344 this->output_file_size_ = off;
1349 // Create a note header following the format defined in the ELF ABI.
1350 // NAME is the name, NOTE_TYPE is the type, DESCSZ is the size of the
1351 // descriptor. ALLOCATE is true if the section should be allocated in
1352 // memory. This returns the new note section. It sets
1353 // *TRAILING_PADDING to the number of trailing zero bytes required.
1356 Layout::create_note(const char* name, int note_type,
1357 const char* section_name, size_t descsz,
1358 bool allocate, size_t* trailing_padding)
1360 // Authorities all agree that the values in a .note field should
1361 // be aligned on 4-byte boundaries for 32-bit binaries. However,
1362 // they differ on what the alignment is for 64-bit binaries.
1363 // The GABI says unambiguously they take 8-byte alignment:
1364 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
1365 // Other documentation says alignment should always be 4 bytes:
1366 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
1367 // GNU ld and GNU readelf both support the latter (at least as of
1368 // version 2.16.91), and glibc always generates the latter for
1369 // .note.ABI-tag (as of version 1.6), so that's the one we go with
1371 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
1372 const int size = parameters->target().get_size();
1374 const int size = 32;
1377 // The contents of the .note section.
1378 size_t namesz = strlen(name) + 1;
1379 size_t aligned_namesz = align_address(namesz, size / 8);
1380 size_t aligned_descsz = align_address(descsz, size / 8);
1382 size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
1384 unsigned char* buffer = new unsigned char[notehdrsz];
1385 memset(buffer, 0, notehdrsz);
1387 bool is_big_endian = parameters->target().is_big_endian();
1393 elfcpp::Swap<32, false>::writeval(buffer, namesz);
1394 elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
1395 elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
1399 elfcpp::Swap<32, true>::writeval(buffer, namesz);
1400 elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
1401 elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
1404 else if (size == 64)
1408 elfcpp::Swap<64, false>::writeval(buffer, namesz);
1409 elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
1410 elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
1414 elfcpp::Swap<64, true>::writeval(buffer, namesz);
1415 elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
1416 elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
1422 memcpy(buffer + 3 * (size / 8), name, namesz);
1424 const char *note_name = this->namepool_.add(section_name, false, NULL);
1425 elfcpp::Elf_Xword flags = 0;
1427 flags = elfcpp::SHF_ALLOC;
1428 Output_section* os = this->make_output_section(note_name,
1431 Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
1434 os->add_output_section_data(posd);
1436 *trailing_padding = aligned_descsz - descsz;
1441 // For an executable or shared library, create a note to record the
1442 // version of gold used to create the binary.
1445 Layout::create_gold_note()
1447 if (parameters->options().relocatable())
1450 std::string desc = std::string("gold ") + gold::get_version_string();
1452 size_t trailing_padding;
1453 Output_section *os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
1454 ".note.gnu.gold-version", desc.size(),
1455 false, &trailing_padding);
1457 Output_section_data* posd = new Output_data_const(desc, 4);
1458 os->add_output_section_data(posd);
1460 if (trailing_padding > 0)
1462 posd = new Output_data_zero_fill(trailing_padding, 0);
1463 os->add_output_section_data(posd);
1467 // Record whether the stack should be executable. This can be set
1468 // from the command line using the -z execstack or -z noexecstack
1469 // options. Otherwise, if any input file has a .note.GNU-stack
1470 // section with the SHF_EXECINSTR flag set, the stack should be
1471 // executable. Otherwise, if at least one input file a
1472 // .note.GNU-stack section, and some input file has no .note.GNU-stack
1473 // section, we use the target default for whether the stack should be
1474 // executable. Otherwise, we don't generate a stack note. When
1475 // generating a object file, we create a .note.GNU-stack section with
1476 // the appropriate marking. When generating an executable or shared
1477 // library, we create a PT_GNU_STACK segment.
1480 Layout::create_executable_stack_info(const Target* target)
1482 bool is_stack_executable;
1483 if (parameters->options().is_execstack_set())
1484 is_stack_executable = parameters->options().is_stack_executable();
1485 else if (!this->input_with_gnu_stack_note_)
1489 if (this->input_requires_executable_stack_)
1490 is_stack_executable = true;
1491 else if (this->input_without_gnu_stack_note_)
1492 is_stack_executable = target->is_default_stack_executable();
1494 is_stack_executable = false;
1497 if (parameters->options().relocatable())
1499 const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
1500 elfcpp::Elf_Xword flags = 0;
1501 if (is_stack_executable)
1502 flags |= elfcpp::SHF_EXECINSTR;
1503 this->make_output_section(name, elfcpp::SHT_PROGBITS, flags);
1507 if (this->script_options_->saw_phdrs_clause())
1509 int flags = elfcpp::PF_R | elfcpp::PF_W;
1510 if (is_stack_executable)
1511 flags |= elfcpp::PF_X;
1512 this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
1516 // If --build-id was used, set up the build ID note.
1519 Layout::create_build_id()
1521 if (!parameters->options().user_set_build_id())
1524 const char* style = parameters->options().build_id();
1525 if (strcmp(style, "none") == 0)
1528 // Set DESCSZ to the size of the note descriptor. When possible,
1529 // set DESC to the note descriptor contents.
1532 if (strcmp(style, "md5") == 0)
1534 else if (strcmp(style, "sha1") == 0)
1536 else if (strcmp(style, "uuid") == 0)
1538 const size_t uuidsz = 128 / 8;
1540 char buffer[uuidsz];
1541 memset(buffer, 0, uuidsz);
1543 int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
1545 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
1549 ssize_t got = ::read(descriptor, buffer, uuidsz);
1550 release_descriptor(descriptor, true);
1552 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
1553 else if (static_cast<size_t>(got) != uuidsz)
1554 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
1558 desc.assign(buffer, uuidsz);
1561 else if (strncmp(style, "0x", 2) == 0)
1564 const char* p = style + 2;
1567 if (hex_p(p[0]) && hex_p(p[1]))
1569 char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
1573 else if (*p == '-' || *p == ':')
1576 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
1579 descsz = desc.size();
1582 gold_fatal(_("unrecognized --build-id argument '%s'"), style);
1585 size_t trailing_padding;
1586 Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
1587 ".note.gnu.build-id", descsz, true,
1592 // We know the value already, so we fill it in now.
1593 gold_assert(desc.size() == descsz);
1595 Output_section_data* posd = new Output_data_const(desc, 4);
1596 os->add_output_section_data(posd);
1598 if (trailing_padding != 0)
1600 posd = new Output_data_zero_fill(trailing_padding, 0);
1601 os->add_output_section_data(posd);
1606 // We need to compute a checksum after we have completed the
1608 gold_assert(trailing_padding == 0);
1609 this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
1610 os->add_output_section_data(this->build_id_note_);
1611 os->set_after_input_sections();
1615 // Create .gnu_incremental_inputs and .gnu_incremental_strtab sections needed
1616 // for the next run of incremental linking to check what has changed.
1619 Layout::create_incremental_info_sections()
1621 gold_assert(this->incremental_inputs_ != NULL);
1623 // Add the .gnu_incremental_inputs section.
1624 const char *incremental_inputs_name =
1625 this->namepool_.add(".gnu_incremental_inputs", false, NULL);
1626 Output_section* inputs_os =
1627 this->make_output_section(incremental_inputs_name,
1628 elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0);
1629 Output_section_data* posd =
1630 this->incremental_inputs_->create_incremental_inputs_section_data();
1631 inputs_os->add_output_section_data(posd);
1633 // Add the .gnu_incremental_strtab section.
1634 const char *incremental_strtab_name =
1635 this->namepool_.add(".gnu_incremental_strtab", false, NULL);
1636 Output_section* strtab_os = this->make_output_section(incremental_strtab_name,
1639 Output_data_strtab* strtab_data =
1640 new Output_data_strtab(this->incremental_inputs_->get_stringpool());
1641 strtab_os->add_output_section_data(strtab_data);
1643 inputs_os->set_link_section(strtab_data);
1646 // Return whether SEG1 should be before SEG2 in the output file. This
1647 // is based entirely on the segment type and flags. When this is
1648 // called the segment addresses has normally not yet been set.
1651 Layout::segment_precedes(const Output_segment* seg1,
1652 const Output_segment* seg2)
1654 elfcpp::Elf_Word type1 = seg1->type();
1655 elfcpp::Elf_Word type2 = seg2->type();
1657 // The single PT_PHDR segment is required to precede any loadable
1658 // segment. We simply make it always first.
1659 if (type1 == elfcpp::PT_PHDR)
1661 gold_assert(type2 != elfcpp::PT_PHDR);
1664 if (type2 == elfcpp::PT_PHDR)
1667 // The single PT_INTERP segment is required to precede any loadable
1668 // segment. We simply make it always second.
1669 if (type1 == elfcpp::PT_INTERP)
1671 gold_assert(type2 != elfcpp::PT_INTERP);
1674 if (type2 == elfcpp::PT_INTERP)
1677 // We then put PT_LOAD segments before any other segments.
1678 if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
1680 if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
1683 // We put the PT_TLS segment last except for the PT_GNU_RELRO
1684 // segment, because that is where the dynamic linker expects to find
1685 // it (this is just for efficiency; other positions would also work
1687 if (type1 == elfcpp::PT_TLS
1688 && type2 != elfcpp::PT_TLS
1689 && type2 != elfcpp::PT_GNU_RELRO)
1691 if (type2 == elfcpp::PT_TLS
1692 && type1 != elfcpp::PT_TLS
1693 && type1 != elfcpp::PT_GNU_RELRO)
1696 // We put the PT_GNU_RELRO segment last, because that is where the
1697 // dynamic linker expects to find it (as with PT_TLS, this is just
1699 if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
1701 if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
1704 const elfcpp::Elf_Word flags1 = seg1->flags();
1705 const elfcpp::Elf_Word flags2 = seg2->flags();
1707 // The order of non-PT_LOAD segments is unimportant. We simply sort
1708 // by the numeric segment type and flags values. There should not
1709 // be more than one segment with the same type and flags.
1710 if (type1 != elfcpp::PT_LOAD)
1713 return type1 < type2;
1714 gold_assert(flags1 != flags2);
1715 return flags1 < flags2;
1718 // If the addresses are set already, sort by load address.
1719 if (seg1->are_addresses_set())
1721 if (!seg2->are_addresses_set())
1724 unsigned int section_count1 = seg1->output_section_count();
1725 unsigned int section_count2 = seg2->output_section_count();
1726 if (section_count1 == 0 && section_count2 > 0)
1728 if (section_count1 > 0 && section_count2 == 0)
1731 uint64_t paddr1 = seg1->first_section_load_address();
1732 uint64_t paddr2 = seg2->first_section_load_address();
1733 if (paddr1 != paddr2)
1734 return paddr1 < paddr2;
1736 else if (seg2->are_addresses_set())
1739 // A segment which holds large data comes after a segment which does
1740 // not hold large data.
1741 if (seg1->is_large_data_segment())
1743 if (!seg2->is_large_data_segment())
1746 else if (seg2->is_large_data_segment())
1749 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
1750 // segments come before writable segments. Then writable segments
1751 // with data come before writable segments without data. Then
1752 // executable segments come before non-executable segments. Then
1753 // the unlikely case of a non-readable segment comes before the
1754 // normal case of a readable segment. If there are multiple
1755 // segments with the same type and flags, we require that the
1756 // address be set, and we sort by virtual address and then physical
1758 if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
1759 return (flags1 & elfcpp::PF_W) == 0;
1760 if ((flags1 & elfcpp::PF_W) != 0
1761 && seg1->has_any_data_sections() != seg2->has_any_data_sections())
1762 return seg1->has_any_data_sections();
1763 if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
1764 return (flags1 & elfcpp::PF_X) != 0;
1765 if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
1766 return (flags1 & elfcpp::PF_R) == 0;
1768 // We shouldn't get here--we shouldn't create segments which we
1769 // can't distinguish.
1773 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
1776 align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
1778 uint64_t unsigned_off = off;
1779 uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
1780 | (addr & (abi_pagesize - 1)));
1781 if (aligned_off < unsigned_off)
1782 aligned_off += abi_pagesize;
1786 // Set the file offsets of all the segments, and all the sections they
1787 // contain. They have all been created. LOAD_SEG must be be laid out
1788 // first. Return the offset of the data to follow.
1791 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
1792 unsigned int *pshndx)
1794 // Sort them into the final order.
1795 std::sort(this->segment_list_.begin(), this->segment_list_.end(),
1796 Layout::Compare_segments());
1798 // Find the PT_LOAD segments, and set their addresses and offsets
1799 // and their section's addresses and offsets.
1801 if (parameters->options().user_set_Ttext())
1802 addr = parameters->options().Ttext();
1803 else if (parameters->options().shared())
1806 addr = target->default_text_segment_address();
1809 // If LOAD_SEG is NULL, then the file header and segment headers
1810 // will not be loadable. But they still need to be at offset 0 in
1811 // the file. Set their offsets now.
1812 if (load_seg == NULL)
1814 for (Data_list::iterator p = this->special_output_list_.begin();
1815 p != this->special_output_list_.end();
1818 off = align_address(off, (*p)->addralign());
1819 (*p)->set_address_and_file_offset(0, off);
1820 off += (*p)->data_size();
1824 const bool check_sections = parameters->options().check_sections();
1825 Output_segment* last_load_segment = NULL;
1827 bool was_readonly = false;
1828 for (Segment_list::iterator p = this->segment_list_.begin();
1829 p != this->segment_list_.end();
1832 if ((*p)->type() == elfcpp::PT_LOAD)
1834 if (load_seg != NULL && load_seg != *p)
1838 bool are_addresses_set = (*p)->are_addresses_set();
1839 if (are_addresses_set)
1841 // When it comes to setting file offsets, we care about
1842 // the physical address.
1843 addr = (*p)->paddr();
1845 else if (parameters->options().user_set_Tdata()
1846 && ((*p)->flags() & elfcpp::PF_W) != 0
1847 && (!parameters->options().user_set_Tbss()
1848 || (*p)->has_any_data_sections()))
1850 addr = parameters->options().Tdata();
1851 are_addresses_set = true;
1853 else if (parameters->options().user_set_Tbss()
1854 && ((*p)->flags() & elfcpp::PF_W) != 0
1855 && !(*p)->has_any_data_sections())
1857 addr = parameters->options().Tbss();
1858 are_addresses_set = true;
1861 uint64_t orig_addr = addr;
1862 uint64_t orig_off = off;
1864 uint64_t aligned_addr = 0;
1865 uint64_t abi_pagesize = target->abi_pagesize();
1866 uint64_t common_pagesize = target->common_pagesize();
1868 if (!parameters->options().nmagic()
1869 && !parameters->options().omagic())
1870 (*p)->set_minimum_p_align(common_pagesize);
1872 if (!are_addresses_set)
1874 // If the last segment was readonly, and this one is
1875 // not, then skip the address forward one page,
1876 // maintaining the same position within the page. This
1877 // lets us store both segments overlapping on a single
1878 // page in the file, but the loader will put them on
1879 // different pages in memory.
1881 addr = align_address(addr, (*p)->maximum_alignment());
1882 aligned_addr = addr;
1884 if (was_readonly && ((*p)->flags() & elfcpp::PF_W) != 0)
1886 if ((addr & (abi_pagesize - 1)) != 0)
1887 addr = addr + abi_pagesize;
1890 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
1893 if (!parameters->options().nmagic()
1894 && !parameters->options().omagic())
1895 off = align_file_offset(off, addr, abi_pagesize);
1897 unsigned int shndx_hold = *pshndx;
1898 uint64_t new_addr = (*p)->set_section_addresses(this, false, addr,
1901 // Now that we know the size of this segment, we may be able
1902 // to save a page in memory, at the cost of wasting some
1903 // file space, by instead aligning to the start of a new
1904 // page. Here we use the real machine page size rather than
1905 // the ABI mandated page size.
1907 if (!are_addresses_set && aligned_addr != addr)
1909 uint64_t first_off = (common_pagesize
1911 & (common_pagesize - 1)));
1912 uint64_t last_off = new_addr & (common_pagesize - 1);
1915 && ((aligned_addr & ~ (common_pagesize - 1))
1916 != (new_addr & ~ (common_pagesize - 1)))
1917 && first_off + last_off <= common_pagesize)
1919 *pshndx = shndx_hold;
1920 addr = align_address(aligned_addr, common_pagesize);
1921 addr = align_address(addr, (*p)->maximum_alignment());
1922 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
1923 off = align_file_offset(off, addr, abi_pagesize);
1924 new_addr = (*p)->set_section_addresses(this, true, addr,
1931 if (((*p)->flags() & elfcpp::PF_W) == 0)
1932 was_readonly = true;
1934 // Implement --check-sections. We know that the segments
1935 // are sorted by LMA.
1936 if (check_sections && last_load_segment != NULL)
1938 gold_assert(last_load_segment->paddr() <= (*p)->paddr());
1939 if (last_load_segment->paddr() + last_load_segment->memsz()
1942 unsigned long long lb1 = last_load_segment->paddr();
1943 unsigned long long le1 = lb1 + last_load_segment->memsz();
1944 unsigned long long lb2 = (*p)->paddr();
1945 unsigned long long le2 = lb2 + (*p)->memsz();
1946 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
1947 "[0x%llx -> 0x%llx]"),
1948 lb1, le1, lb2, le2);
1951 last_load_segment = *p;
1955 // Handle the non-PT_LOAD segments, setting their offsets from their
1956 // section's offsets.
1957 for (Segment_list::iterator p = this->segment_list_.begin();
1958 p != this->segment_list_.end();
1961 if ((*p)->type() != elfcpp::PT_LOAD)
1965 // Set the TLS offsets for each section in the PT_TLS segment.
1966 if (this->tls_segment_ != NULL)
1967 this->tls_segment_->set_tls_offsets();
1972 // Set the offsets of all the allocated sections when doing a
1973 // relocatable link. This does the same jobs as set_segment_offsets,
1974 // only for a relocatable link.
1977 Layout::set_relocatable_section_offsets(Output_data* file_header,
1978 unsigned int *pshndx)
1982 file_header->set_address_and_file_offset(0, 0);
1983 off += file_header->data_size();
1985 for (Section_list::iterator p = this->section_list_.begin();
1986 p != this->section_list_.end();
1989 // We skip unallocated sections here, except that group sections
1990 // have to come first.
1991 if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
1992 && (*p)->type() != elfcpp::SHT_GROUP)
1995 off = align_address(off, (*p)->addralign());
1997 // The linker script might have set the address.
1998 if (!(*p)->is_address_valid())
1999 (*p)->set_address(0);
2000 (*p)->set_file_offset(off);
2001 (*p)->finalize_data_size();
2002 off += (*p)->data_size();
2004 (*p)->set_out_shndx(*pshndx);
2011 // Set the file offset of all the sections not associated with a
2015 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
2017 for (Section_list::iterator p = this->unattached_section_list_.begin();
2018 p != this->unattached_section_list_.end();
2021 // The symtab section is handled in create_symtab_sections.
2022 if (*p == this->symtab_section_)
2025 // If we've already set the data size, don't set it again.
2026 if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
2029 if (pass == BEFORE_INPUT_SECTIONS_PASS
2030 && (*p)->requires_postprocessing())
2032 (*p)->create_postprocessing_buffer();
2033 this->any_postprocessing_sections_ = true;
2036 if (pass == BEFORE_INPUT_SECTIONS_PASS
2037 && (*p)->after_input_sections())
2039 else if (pass == POSTPROCESSING_SECTIONS_PASS
2040 && (!(*p)->after_input_sections()
2041 || (*p)->type() == elfcpp::SHT_STRTAB))
2043 else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
2044 && (!(*p)->after_input_sections()
2045 || (*p)->type() != elfcpp::SHT_STRTAB))
2048 off = align_address(off, (*p)->addralign());
2049 (*p)->set_file_offset(off);
2050 (*p)->finalize_data_size();
2051 off += (*p)->data_size();
2053 // At this point the name must be set.
2054 if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
2055 this->namepool_.add((*p)->name(), false, NULL);
2060 // Set the section indexes of all the sections not associated with a
2064 Layout::set_section_indexes(unsigned int shndx)
2066 for (Section_list::iterator p = this->unattached_section_list_.begin();
2067 p != this->unattached_section_list_.end();
2070 if (!(*p)->has_out_shndx())
2072 (*p)->set_out_shndx(shndx);
2079 // Set the section addresses according to the linker script. This is
2080 // only called when we see a SECTIONS clause. This returns the
2081 // program segment which should hold the file header and segment
2082 // headers, if any. It will return NULL if they should not be in a
2086 Layout::set_section_addresses_from_script(Symbol_table* symtab)
2088 Script_sections* ss = this->script_options_->script_sections();
2089 gold_assert(ss->saw_sections_clause());
2091 // Place each orphaned output section in the script.
2092 for (Section_list::iterator p = this->section_list_.begin();
2093 p != this->section_list_.end();
2096 if (!(*p)->found_in_sections_clause())
2097 ss->place_orphan(*p);
2100 return this->script_options_->set_section_addresses(symtab, this);
2103 // Count the local symbols in the regular symbol table and the dynamic
2104 // symbol table, and build the respective string pools.
2107 Layout::count_local_symbols(const Task* task,
2108 const Input_objects* input_objects)
2110 // First, figure out an upper bound on the number of symbols we'll
2111 // be inserting into each pool. This helps us create the pools with
2112 // the right size, to avoid unnecessary hashtable resizing.
2113 unsigned int symbol_count = 0;
2114 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2115 p != input_objects->relobj_end();
2117 symbol_count += (*p)->local_symbol_count();
2119 // Go from "upper bound" to "estimate." We overcount for two
2120 // reasons: we double-count symbols that occur in more than one
2121 // object file, and we count symbols that are dropped from the
2122 // output. Add it all together and assume we overcount by 100%.
2125 // We assume all symbols will go into both the sympool and dynpool.
2126 this->sympool_.reserve(symbol_count);
2127 this->dynpool_.reserve(symbol_count);
2129 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2130 p != input_objects->relobj_end();
2133 Task_lock_obj<Object> tlo(task, *p);
2134 (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
2138 // Create the symbol table sections. Here we also set the final
2139 // values of the symbols. At this point all the loadable sections are
2140 // fully laid out. SHNUM is the number of sections so far.
2143 Layout::create_symtab_sections(const Input_objects* input_objects,
2144 Symbol_table* symtab,
2150 if (parameters->target().get_size() == 32)
2152 symsize = elfcpp::Elf_sizes<32>::sym_size;
2155 else if (parameters->target().get_size() == 64)
2157 symsize = elfcpp::Elf_sizes<64>::sym_size;
2164 off = align_address(off, align);
2165 off_t startoff = off;
2167 // Save space for the dummy symbol at the start of the section. We
2168 // never bother to write this out--it will just be left as zero.
2170 unsigned int local_symbol_index = 1;
2172 // Add STT_SECTION symbols for each Output section which needs one.
2173 for (Section_list::iterator p = this->section_list_.begin();
2174 p != this->section_list_.end();
2177 if (!(*p)->needs_symtab_index())
2178 (*p)->set_symtab_index(-1U);
2181 (*p)->set_symtab_index(local_symbol_index);
2182 ++local_symbol_index;
2187 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2188 p != input_objects->relobj_end();
2191 unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
2193 off += (index - local_symbol_index) * symsize;
2194 local_symbol_index = index;
2197 unsigned int local_symcount = local_symbol_index;
2198 gold_assert(local_symcount * symsize == off - startoff);
2201 size_t dyn_global_index;
2203 if (this->dynsym_section_ == NULL)
2206 dyn_global_index = 0;
2211 dyn_global_index = this->dynsym_section_->info();
2212 off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
2213 dynoff = this->dynsym_section_->offset() + locsize;
2214 dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
2215 gold_assert(static_cast<off_t>(dyncount * symsize)
2216 == this->dynsym_section_->data_size() - locsize);
2219 off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
2220 &this->sympool_, &local_symcount);
2222 if (!parameters->options().strip_all())
2224 this->sympool_.set_string_offsets();
2226 const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
2227 Output_section* osymtab = this->make_output_section(symtab_name,
2230 this->symtab_section_ = osymtab;
2232 Output_section_data* pos = new Output_data_fixed_space(off - startoff,
2235 osymtab->add_output_section_data(pos);
2237 // We generate a .symtab_shndx section if we have more than
2238 // SHN_LORESERVE sections. Technically it is possible that we
2239 // don't need one, because it is possible that there are no
2240 // symbols in any of sections with indexes larger than
2241 // SHN_LORESERVE. That is probably unusual, though, and it is
2242 // easier to always create one than to compute section indexes
2243 // twice (once here, once when writing out the symbols).
2244 if (shnum >= elfcpp::SHN_LORESERVE)
2246 const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
2248 Output_section* osymtab_xindex =
2249 this->make_output_section(symtab_xindex_name,
2250 elfcpp::SHT_SYMTAB_SHNDX, 0);
2252 size_t symcount = (off - startoff) / symsize;
2253 this->symtab_xindex_ = new Output_symtab_xindex(symcount);
2255 osymtab_xindex->add_output_section_data(this->symtab_xindex_);
2257 osymtab_xindex->set_link_section(osymtab);
2258 osymtab_xindex->set_addralign(4);
2259 osymtab_xindex->set_entsize(4);
2261 osymtab_xindex->set_after_input_sections();
2263 // This tells the driver code to wait until the symbol table
2264 // has written out before writing out the postprocessing
2265 // sections, including the .symtab_shndx section.
2266 this->any_postprocessing_sections_ = true;
2269 const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
2270 Output_section* ostrtab = this->make_output_section(strtab_name,
2274 Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
2275 ostrtab->add_output_section_data(pstr);
2277 osymtab->set_file_offset(startoff);
2278 osymtab->finalize_data_size();
2279 osymtab->set_link_section(ostrtab);
2280 osymtab->set_info(local_symcount);
2281 osymtab->set_entsize(symsize);
2287 // Create the .shstrtab section, which holds the names of the
2288 // sections. At the time this is called, we have created all the
2289 // output sections except .shstrtab itself.
2292 Layout::create_shstrtab()
2294 // FIXME: We don't need to create a .shstrtab section if we are
2295 // stripping everything.
2297 const char* name = this->namepool_.add(".shstrtab", false, NULL);
2299 Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0);
2301 // We can't write out this section until we've set all the section
2302 // names, and we don't set the names of compressed output sections
2303 // until relocations are complete.
2304 os->set_after_input_sections();
2306 Output_section_data* posd = new Output_data_strtab(&this->namepool_);
2307 os->add_output_section_data(posd);
2312 // Create the section headers. SIZE is 32 or 64. OFF is the file
2316 Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
2318 Output_section_headers* oshdrs;
2319 oshdrs = new Output_section_headers(this,
2320 &this->segment_list_,
2321 &this->section_list_,
2322 &this->unattached_section_list_,
2325 off_t off = align_address(*poff, oshdrs->addralign());
2326 oshdrs->set_address_and_file_offset(0, off);
2327 off += oshdrs->data_size();
2329 this->section_headers_ = oshdrs;
2332 // Count the allocated sections.
2335 Layout::allocated_output_section_count() const
2337 size_t section_count = 0;
2338 for (Segment_list::const_iterator p = this->segment_list_.begin();
2339 p != this->segment_list_.end();
2341 section_count += (*p)->output_section_count();
2342 return section_count;
2345 // Create the dynamic symbol table.
2348 Layout::create_dynamic_symtab(const Input_objects* input_objects,
2349 Symbol_table* symtab,
2350 Output_section **pdynstr,
2351 unsigned int* plocal_dynamic_count,
2352 std::vector<Symbol*>* pdynamic_symbols,
2353 Versions* pversions)
2355 // Count all the symbols in the dynamic symbol table, and set the
2356 // dynamic symbol indexes.
2358 // Skip symbol 0, which is always all zeroes.
2359 unsigned int index = 1;
2361 // Add STT_SECTION symbols for each Output section which needs one.
2362 for (Section_list::iterator p = this->section_list_.begin();
2363 p != this->section_list_.end();
2366 if (!(*p)->needs_dynsym_index())
2367 (*p)->set_dynsym_index(-1U);
2370 (*p)->set_dynsym_index(index);
2375 // Count the local symbols that need to go in the dynamic symbol table,
2376 // and set the dynamic symbol indexes.
2377 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2378 p != input_objects->relobj_end();
2381 unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
2385 unsigned int local_symcount = index;
2386 *plocal_dynamic_count = local_symcount;
2388 index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
2389 &this->dynpool_, pversions);
2393 const int size = parameters->target().get_size();
2396 symsize = elfcpp::Elf_sizes<32>::sym_size;
2399 else if (size == 64)
2401 symsize = elfcpp::Elf_sizes<64>::sym_size;
2407 // Create the dynamic symbol table section.
2409 Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
2414 Output_section_data* odata = new Output_data_fixed_space(index * symsize,
2417 dynsym->add_output_section_data(odata);
2419 dynsym->set_info(local_symcount);
2420 dynsym->set_entsize(symsize);
2421 dynsym->set_addralign(align);
2423 this->dynsym_section_ = dynsym;
2425 Output_data_dynamic* const odyn = this->dynamic_data_;
2426 odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
2427 odyn->add_constant(elfcpp::DT_SYMENT, symsize);
2429 // If there are more than SHN_LORESERVE allocated sections, we
2430 // create a .dynsym_shndx section. It is possible that we don't
2431 // need one, because it is possible that there are no dynamic
2432 // symbols in any of the sections with indexes larger than
2433 // SHN_LORESERVE. This is probably unusual, though, and at this
2434 // time we don't know the actual section indexes so it is
2435 // inconvenient to check.
2436 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
2438 Output_section* dynsym_xindex =
2439 this->choose_output_section(NULL, ".dynsym_shndx",
2440 elfcpp::SHT_SYMTAB_SHNDX,
2444 this->dynsym_xindex_ = new Output_symtab_xindex(index);
2446 dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
2448 dynsym_xindex->set_link_section(dynsym);
2449 dynsym_xindex->set_addralign(4);
2450 dynsym_xindex->set_entsize(4);
2452 dynsym_xindex->set_after_input_sections();
2454 // This tells the driver code to wait until the symbol table has
2455 // written out before writing out the postprocessing sections,
2456 // including the .dynsym_shndx section.
2457 this->any_postprocessing_sections_ = true;
2460 // Create the dynamic string table section.
2462 Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
2467 Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
2468 dynstr->add_output_section_data(strdata);
2470 dynsym->set_link_section(dynstr);
2471 this->dynamic_section_->set_link_section(dynstr);
2473 odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
2474 odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
2478 // Create the hash tables.
2480 if (strcmp(parameters->options().hash_style(), "sysv") == 0
2481 || strcmp(parameters->options().hash_style(), "both") == 0)
2483 unsigned char* phash;
2484 unsigned int hashlen;
2485 Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
2488 Output_section* hashsec = this->choose_output_section(NULL, ".hash",
2493 Output_section_data* hashdata = new Output_data_const_buffer(phash,
2497 hashsec->add_output_section_data(hashdata);
2499 hashsec->set_link_section(dynsym);
2500 hashsec->set_entsize(4);
2502 odyn->add_section_address(elfcpp::DT_HASH, hashsec);
2505 if (strcmp(parameters->options().hash_style(), "gnu") == 0
2506 || strcmp(parameters->options().hash_style(), "both") == 0)
2508 unsigned char* phash;
2509 unsigned int hashlen;
2510 Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
2513 Output_section* hashsec = this->choose_output_section(NULL, ".gnu.hash",
2514 elfcpp::SHT_GNU_HASH,
2518 Output_section_data* hashdata = new Output_data_const_buffer(phash,
2522 hashsec->add_output_section_data(hashdata);
2524 hashsec->set_link_section(dynsym);
2525 hashsec->set_entsize(4);
2527 odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
2531 // Assign offsets to each local portion of the dynamic symbol table.
2534 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
2536 Output_section* dynsym = this->dynsym_section_;
2537 gold_assert(dynsym != NULL);
2539 off_t off = dynsym->offset();
2541 // Skip the dummy symbol at the start of the section.
2542 off += dynsym->entsize();
2544 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
2545 p != input_objects->relobj_end();
2548 unsigned int count = (*p)->set_local_dynsym_offset(off);
2549 off += count * dynsym->entsize();
2553 // Create the version sections.
2556 Layout::create_version_sections(const Versions* versions,
2557 const Symbol_table* symtab,
2558 unsigned int local_symcount,
2559 const std::vector<Symbol*>& dynamic_symbols,
2560 const Output_section* dynstr)
2562 if (!versions->any_defs() && !versions->any_needs())
2565 switch (parameters->size_and_endianness())
2567 #ifdef HAVE_TARGET_32_LITTLE
2568 case Parameters::TARGET_32_LITTLE:
2569 this->sized_create_version_sections<32, false>(versions, symtab,
2571 dynamic_symbols, dynstr);
2574 #ifdef HAVE_TARGET_32_BIG
2575 case Parameters::TARGET_32_BIG:
2576 this->sized_create_version_sections<32, true>(versions, symtab,
2578 dynamic_symbols, dynstr);
2581 #ifdef HAVE_TARGET_64_LITTLE
2582 case Parameters::TARGET_64_LITTLE:
2583 this->sized_create_version_sections<64, false>(versions, symtab,
2585 dynamic_symbols, dynstr);
2588 #ifdef HAVE_TARGET_64_BIG
2589 case Parameters::TARGET_64_BIG:
2590 this->sized_create_version_sections<64, true>(versions, symtab,
2592 dynamic_symbols, dynstr);
2600 // Create the version sections, sized version.
2602 template<int size, bool big_endian>
2604 Layout::sized_create_version_sections(
2605 const Versions* versions,
2606 const Symbol_table* symtab,
2607 unsigned int local_symcount,
2608 const std::vector<Symbol*>& dynamic_symbols,
2609 const Output_section* dynstr)
2611 Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
2612 elfcpp::SHT_GNU_versym,
2616 unsigned char* vbuf;
2618 versions->symbol_section_contents<size, big_endian>(symtab, &this->dynpool_,
2623 Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
2626 vsec->add_output_section_data(vdata);
2627 vsec->set_entsize(2);
2628 vsec->set_link_section(this->dynsym_section_);
2630 Output_data_dynamic* const odyn = this->dynamic_data_;
2631 odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
2633 if (versions->any_defs())
2635 Output_section* vdsec;
2636 vdsec= this->choose_output_section(NULL, ".gnu.version_d",
2637 elfcpp::SHT_GNU_verdef,
2641 unsigned char* vdbuf;
2642 unsigned int vdsize;
2643 unsigned int vdentries;
2644 versions->def_section_contents<size, big_endian>(&this->dynpool_, &vdbuf,
2645 &vdsize, &vdentries);
2647 Output_section_data* vddata =
2648 new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
2650 vdsec->add_output_section_data(vddata);
2651 vdsec->set_link_section(dynstr);
2652 vdsec->set_info(vdentries);
2654 odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
2655 odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
2658 if (versions->any_needs())
2660 Output_section* vnsec;
2661 vnsec = this->choose_output_section(NULL, ".gnu.version_r",
2662 elfcpp::SHT_GNU_verneed,
2666 unsigned char* vnbuf;
2667 unsigned int vnsize;
2668 unsigned int vnentries;
2669 versions->need_section_contents<size, big_endian>(&this->dynpool_,
2673 Output_section_data* vndata =
2674 new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
2676 vnsec->add_output_section_data(vndata);
2677 vnsec->set_link_section(dynstr);
2678 vnsec->set_info(vnentries);
2680 odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
2681 odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
2685 // Create the .interp section and PT_INTERP segment.
2688 Layout::create_interp(const Target* target)
2690 const char* interp = parameters->options().dynamic_linker();
2693 interp = target->dynamic_linker();
2694 gold_assert(interp != NULL);
2697 size_t len = strlen(interp) + 1;
2699 Output_section_data* odata = new Output_data_const(interp, len, 1);
2701 Output_section* osec = this->choose_output_section(NULL, ".interp",
2702 elfcpp::SHT_PROGBITS,
2705 osec->add_output_section_data(odata);
2707 if (!this->script_options_->saw_phdrs_clause())
2709 Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP,
2711 oseg->add_output_section(osec, elfcpp::PF_R);
2715 // Finish the .dynamic section and PT_DYNAMIC segment.
2718 Layout::finish_dynamic_section(const Input_objects* input_objects,
2719 const Symbol_table* symtab)
2721 if (!this->script_options_->saw_phdrs_clause())
2723 Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
2726 oseg->add_output_section(this->dynamic_section_,
2727 elfcpp::PF_R | elfcpp::PF_W);
2730 Output_data_dynamic* const odyn = this->dynamic_data_;
2732 for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
2733 p != input_objects->dynobj_end();
2736 // FIXME: Handle --as-needed.
2737 odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
2740 if (parameters->options().shared())
2742 const char* soname = parameters->options().soname();
2744 odyn->add_string(elfcpp::DT_SONAME, soname);
2747 // FIXME: Support --init and --fini.
2748 Symbol* sym = symtab->lookup("_init");
2749 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
2750 odyn->add_symbol(elfcpp::DT_INIT, sym);
2752 sym = symtab->lookup("_fini");
2753 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
2754 odyn->add_symbol(elfcpp::DT_FINI, sym);
2756 // FIXME: Support DT_INIT_ARRAY and DT_FINI_ARRAY.
2758 // Add a DT_RPATH entry if needed.
2759 const General_options::Dir_list& rpath(parameters->options().rpath());
2762 std::string rpath_val;
2763 for (General_options::Dir_list::const_iterator p = rpath.begin();
2767 if (rpath_val.empty())
2768 rpath_val = p->name();
2771 // Eliminate duplicates.
2772 General_options::Dir_list::const_iterator q;
2773 for (q = rpath.begin(); q != p; ++q)
2774 if (q->name() == p->name())
2779 rpath_val += p->name();
2784 odyn->add_string(elfcpp::DT_RPATH, rpath_val);
2785 if (parameters->options().enable_new_dtags())
2786 odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
2789 // Look for text segments that have dynamic relocations.
2790 bool have_textrel = false;
2791 if (!this->script_options_->saw_sections_clause())
2793 for (Segment_list::const_iterator p = this->segment_list_.begin();
2794 p != this->segment_list_.end();
2797 if (((*p)->flags() & elfcpp::PF_W) == 0
2798 && (*p)->dynamic_reloc_count() > 0)
2800 have_textrel = true;
2807 // We don't know the section -> segment mapping, so we are
2808 // conservative and just look for readonly sections with
2809 // relocations. If those sections wind up in writable segments,
2810 // then we have created an unnecessary DT_TEXTREL entry.
2811 for (Section_list::const_iterator p = this->section_list_.begin();
2812 p != this->section_list_.end();
2815 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
2816 && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
2817 && ((*p)->dynamic_reloc_count() > 0))
2819 have_textrel = true;
2825 // Add a DT_FLAGS entry. We add it even if no flags are set so that
2826 // post-link tools can easily modify these flags if desired.
2827 unsigned int flags = 0;
2830 // Add a DT_TEXTREL for compatibility with older loaders.
2831 odyn->add_constant(elfcpp::DT_TEXTREL, 0);
2832 flags |= elfcpp::DF_TEXTREL;
2834 if (parameters->options().shared() && this->has_static_tls())
2835 flags |= elfcpp::DF_STATIC_TLS;
2836 if (parameters->options().origin())
2837 flags |= elfcpp::DF_ORIGIN;
2838 if (parameters->options().now())
2839 flags |= elfcpp::DF_BIND_NOW;
2840 odyn->add_constant(elfcpp::DT_FLAGS, flags);
2843 if (parameters->options().initfirst())
2844 flags |= elfcpp::DF_1_INITFIRST;
2845 if (parameters->options().interpose())
2846 flags |= elfcpp::DF_1_INTERPOSE;
2847 if (parameters->options().loadfltr())
2848 flags |= elfcpp::DF_1_LOADFLTR;
2849 if (parameters->options().nodefaultlib())
2850 flags |= elfcpp::DF_1_NODEFLIB;
2851 if (parameters->options().nodelete())
2852 flags |= elfcpp::DF_1_NODELETE;
2853 if (parameters->options().nodlopen())
2854 flags |= elfcpp::DF_1_NOOPEN;
2855 if (parameters->options().nodump())
2856 flags |= elfcpp::DF_1_NODUMP;
2857 if (!parameters->options().shared())
2858 flags &= ~(elfcpp::DF_1_INITFIRST
2859 | elfcpp::DF_1_NODELETE
2860 | elfcpp::DF_1_NOOPEN);
2861 if (parameters->options().origin())
2862 flags |= elfcpp::DF_1_ORIGIN;
2863 if (parameters->options().now())
2864 flags |= elfcpp::DF_1_NOW;
2866 odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
2869 // The mapping of input section name prefixes to output section names.
2870 // In some cases one prefix is itself a prefix of another prefix; in
2871 // such a case the longer prefix must come first. These prefixes are
2872 // based on the GNU linker default ELF linker script.
2874 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
2875 const Layout::Section_name_mapping Layout::section_name_mapping[] =
2877 MAPPING_INIT(".text.", ".text"),
2878 MAPPING_INIT(".ctors.", ".ctors"),
2879 MAPPING_INIT(".dtors.", ".dtors"),
2880 MAPPING_INIT(".rodata.", ".rodata"),
2881 MAPPING_INIT(".data.rel.ro.local", ".data.rel.ro.local"),
2882 MAPPING_INIT(".data.rel.ro", ".data.rel.ro"),
2883 MAPPING_INIT(".data.", ".data"),
2884 MAPPING_INIT(".bss.", ".bss"),
2885 MAPPING_INIT(".tdata.", ".tdata"),
2886 MAPPING_INIT(".tbss.", ".tbss"),
2887 MAPPING_INIT(".init_array.", ".init_array"),
2888 MAPPING_INIT(".fini_array.", ".fini_array"),
2889 MAPPING_INIT(".sdata.", ".sdata"),
2890 MAPPING_INIT(".sbss.", ".sbss"),
2891 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
2892 // differently depending on whether it is creating a shared library.
2893 MAPPING_INIT(".sdata2.", ".sdata"),
2894 MAPPING_INIT(".sbss2.", ".sbss"),
2895 MAPPING_INIT(".lrodata.", ".lrodata"),
2896 MAPPING_INIT(".ldata.", ".ldata"),
2897 MAPPING_INIT(".lbss.", ".lbss"),
2898 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
2899 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
2900 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
2901 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
2902 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
2903 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
2904 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
2905 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
2906 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
2907 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
2908 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
2909 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
2910 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
2911 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
2912 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
2913 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
2914 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
2915 MAPPING_INIT(".ARM.extab.", ".ARM.extab"),
2916 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
2917 MAPPING_INIT(".ARM.exidx.", ".ARM.exidx"),
2918 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
2922 const int Layout::section_name_mapping_count =
2923 (sizeof(Layout::section_name_mapping)
2924 / sizeof(Layout::section_name_mapping[0]));
2926 // Choose the output section name to use given an input section name.
2927 // Set *PLEN to the length of the name. *PLEN is initialized to the
2931 Layout::output_section_name(const char* name, size_t* plen)
2933 // gcc 4.3 generates the following sorts of section names when it
2934 // needs a section name specific to a function:
2940 // .data.rel.local.FN
2942 // .data.rel.ro.local.FN
2949 // The GNU linker maps all of those to the part before the .FN,
2950 // except that .data.rel.local.FN is mapped to .data, and
2951 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
2952 // beginning with .data.rel.ro.local are grouped together.
2954 // For an anonymous namespace, the string FN can contain a '.'.
2956 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
2957 // GNU linker maps to .rodata.
2959 // The .data.rel.ro sections are used with -z relro. The sections
2960 // are recognized by name. We use the same names that the GNU
2961 // linker does for these sections.
2963 // It is hard to handle this in a principled way, so we don't even
2964 // try. We use a table of mappings. If the input section name is
2965 // not found in the table, we simply use it as the output section
2968 const Section_name_mapping* psnm = section_name_mapping;
2969 for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
2971 if (strncmp(name, psnm->from, psnm->fromlen) == 0)
2973 *plen = psnm->tolen;
2981 // Check if a comdat group or .gnu.linkonce section with the given
2982 // NAME is selected for the link. If there is already a section,
2983 // *KEPT_SECTION is set to point to the signature and the function
2984 // returns false. Otherwise, the CANDIDATE signature is recorded for
2985 // this NAME in the layout object, *KEPT_SECTION is set to the
2986 // internal copy and the function return false. In some cases, with
2987 // CANDIDATE->GROUP_ being false, KEPT_SECTION can point back to
2991 Layout::find_or_add_kept_section(const std::string& name,
2992 Kept_section* candidate,
2993 Kept_section** kept_section)
2995 // It's normal to see a couple of entries here, for the x86 thunk
2996 // sections. If we see more than a few, we're linking a C++
2997 // program, and we resize to get more space to minimize rehashing.
2998 if (this->signatures_.size() > 4
2999 && !this->resized_signatures_)
3001 reserve_unordered_map(&this->signatures_,
3002 this->number_of_input_files_ * 64);
3003 this->resized_signatures_ = true;
3006 std::pair<Signatures::iterator, bool> ins(
3007 this->signatures_.insert(std::make_pair(name, *candidate)));
3010 *kept_section = &ins.first->second;
3013 // This is the first time we've seen this signature.
3017 if (ins.first->second.is_group)
3019 // We've already seen a real section group with this signature.
3020 // If the kept group is from a plugin object, and we're in
3021 // the replacement phase, accept the new one as a replacement.
3022 if (ins.first->second.object == NULL
3023 && parameters->options().plugins()->in_replacement_phase())
3025 ins.first->second = *candidate;
3030 else if (candidate->is_group)
3032 // This is a real section group, and we've already seen a
3033 // linkonce section with this signature. Record that we've seen
3034 // a section group, and don't include this section group.
3035 ins.first->second.is_group = true;
3040 // We've already seen a linkonce section and this is a linkonce
3041 // section. These don't block each other--this may be the same
3042 // symbol name with different section types.
3043 *kept_section = candidate;
3048 // Find the given comdat signature, and return the object and section
3049 // index of the kept group.
3051 Layout::find_kept_object(const std::string& signature,
3052 unsigned int* pshndx) const
3054 Signatures::const_iterator p = this->signatures_.find(signature);
3055 if (p == this->signatures_.end())
3058 *pshndx = p->second.shndx;
3059 return p->second.object;
3062 // Store the allocated sections into the section list.
3065 Layout::get_allocated_sections(Section_list* section_list) const
3067 for (Section_list::const_iterator p = this->section_list_.begin();
3068 p != this->section_list_.end();
3070 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
3071 section_list->push_back(*p);
3074 // Create an output segment.
3077 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
3079 gold_assert(!parameters->options().relocatable());
3080 Output_segment* oseg = new Output_segment(type, flags);
3081 this->segment_list_.push_back(oseg);
3083 if (type == elfcpp::PT_TLS)
3084 this->tls_segment_ = oseg;
3085 else if (type == elfcpp::PT_GNU_RELRO)
3086 this->relro_segment_ = oseg;
3091 // Write out the Output_sections. Most won't have anything to write,
3092 // since most of the data will come from input sections which are
3093 // handled elsewhere. But some Output_sections do have Output_data.
3096 Layout::write_output_sections(Output_file* of) const
3098 for (Section_list::const_iterator p = this->section_list_.begin();
3099 p != this->section_list_.end();
3102 if (!(*p)->after_input_sections())
3107 // Write out data not associated with a section or the symbol table.
3110 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
3112 if (!parameters->options().strip_all())
3114 const Output_section* symtab_section = this->symtab_section_;
3115 for (Section_list::const_iterator p = this->section_list_.begin();
3116 p != this->section_list_.end();
3119 if ((*p)->needs_symtab_index())
3121 gold_assert(symtab_section != NULL);
3122 unsigned int index = (*p)->symtab_index();
3123 gold_assert(index > 0 && index != -1U);
3124 off_t off = (symtab_section->offset()
3125 + index * symtab_section->entsize());
3126 symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
3131 const Output_section* dynsym_section = this->dynsym_section_;
3132 for (Section_list::const_iterator p = this->section_list_.begin();
3133 p != this->section_list_.end();
3136 if ((*p)->needs_dynsym_index())
3138 gold_assert(dynsym_section != NULL);
3139 unsigned int index = (*p)->dynsym_index();
3140 gold_assert(index > 0 && index != -1U);
3141 off_t off = (dynsym_section->offset()
3142 + index * dynsym_section->entsize());
3143 symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
3147 // Write out the Output_data which are not in an Output_section.
3148 for (Data_list::const_iterator p = this->special_output_list_.begin();
3149 p != this->special_output_list_.end();
3154 // Write out the Output_sections which can only be written after the
3155 // input sections are complete.
3158 Layout::write_sections_after_input_sections(Output_file* of)
3160 // Determine the final section offsets, and thus the final output
3161 // file size. Note we finalize the .shstrab last, to allow the
3162 // after_input_section sections to modify their section-names before
3164 if (this->any_postprocessing_sections_)
3166 off_t off = this->output_file_size_;
3167 off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
3169 // Now that we've finalized the names, we can finalize the shstrab.
3171 this->set_section_offsets(off,
3172 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
3174 if (off > this->output_file_size_)
3177 this->output_file_size_ = off;
3181 for (Section_list::const_iterator p = this->section_list_.begin();
3182 p != this->section_list_.end();
3185 if ((*p)->after_input_sections())
3189 this->section_headers_->write(of);
3192 // If the build ID requires computing a checksum, do so here, and
3193 // write it out. We compute a checksum over the entire file because
3194 // that is simplest.
3197 Layout::write_build_id(Output_file* of) const
3199 if (this->build_id_note_ == NULL)
3202 const unsigned char* iv = of->get_input_view(0, this->output_file_size_);
3204 unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
3205 this->build_id_note_->data_size());
3207 const char* style = parameters->options().build_id();
3208 if (strcmp(style, "sha1") == 0)
3211 sha1_init_ctx(&ctx);
3212 sha1_process_bytes(iv, this->output_file_size_, &ctx);
3213 sha1_finish_ctx(&ctx, ov);
3215 else if (strcmp(style, "md5") == 0)
3219 md5_process_bytes(iv, this->output_file_size_, &ctx);
3220 md5_finish_ctx(&ctx, ov);
3225 of->write_output_view(this->build_id_note_->offset(),
3226 this->build_id_note_->data_size(),
3229 of->free_input_view(0, this->output_file_size_, iv);
3232 // Write out a binary file. This is called after the link is
3233 // complete. IN is the temporary output file we used to generate the
3234 // ELF code. We simply walk through the segments, read them from
3235 // their file offset in IN, and write them to their load address in
3236 // the output file. FIXME: with a bit more work, we could support
3237 // S-records and/or Intel hex format here.
3240 Layout::write_binary(Output_file* in) const
3242 gold_assert(parameters->options().oformat_enum()
3243 == General_options::OBJECT_FORMAT_BINARY);
3245 // Get the size of the binary file.
3246 uint64_t max_load_address = 0;
3247 for (Segment_list::const_iterator p = this->segment_list_.begin();
3248 p != this->segment_list_.end();
3251 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
3253 uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
3254 if (max_paddr > max_load_address)
3255 max_load_address = max_paddr;
3259 Output_file out(parameters->options().output_file_name());
3260 out.open(max_load_address);
3262 for (Segment_list::const_iterator p = this->segment_list_.begin();
3263 p != this->segment_list_.end();
3266 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
3268 const unsigned char* vin = in->get_input_view((*p)->offset(),
3270 unsigned char* vout = out.get_output_view((*p)->paddr(),
3272 memcpy(vout, vin, (*p)->filesz());
3273 out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
3274 in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
3281 // Print the output sections to the map file.
3284 Layout::print_to_mapfile(Mapfile* mapfile) const
3286 for (Segment_list::const_iterator p = this->segment_list_.begin();
3287 p != this->segment_list_.end();
3289 (*p)->print_sections_to_mapfile(mapfile);
3292 // Print statistical information to stderr. This is used for --stats.
3295 Layout::print_stats() const
3297 this->namepool_.print_stats("section name pool");
3298 this->sympool_.print_stats("output symbol name pool");
3299 this->dynpool_.print_stats("dynamic name pool");
3301 for (Section_list::const_iterator p = this->section_list_.begin();
3302 p != this->section_list_.end();
3304 (*p)->print_merge_stats();
3307 // Write_sections_task methods.
3309 // We can always run this task.
3312 Write_sections_task::is_runnable()
3317 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
3321 Write_sections_task::locks(Task_locker* tl)
3323 tl->add(this, this->output_sections_blocker_);
3324 tl->add(this, this->final_blocker_);
3327 // Run the task--write out the data.
3330 Write_sections_task::run(Workqueue*)
3332 this->layout_->write_output_sections(this->of_);
3335 // Write_data_task methods.
3337 // We can always run this task.
3340 Write_data_task::is_runnable()
3345 // We need to unlock FINAL_BLOCKER when finished.
3348 Write_data_task::locks(Task_locker* tl)
3350 tl->add(this, this->final_blocker_);
3353 // Run the task--write out the data.
3356 Write_data_task::run(Workqueue*)
3358 this->layout_->write_data(this->symtab_, this->of_);
3361 // Write_symbols_task methods.
3363 // We can always run this task.
3366 Write_symbols_task::is_runnable()
3371 // We need to unlock FINAL_BLOCKER when finished.
3374 Write_symbols_task::locks(Task_locker* tl)
3376 tl->add(this, this->final_blocker_);
3379 // Run the task--write out the symbols.
3382 Write_symbols_task::run(Workqueue*)
3384 this->symtab_->write_globals(this->sympool_, this->dynpool_,
3385 this->layout_->symtab_xindex(),
3386 this->layout_->dynsym_xindex(), this->of_);
3389 // Write_after_input_sections_task methods.
3391 // We can only run this task after the input sections have completed.
3394 Write_after_input_sections_task::is_runnable()
3396 if (this->input_sections_blocker_->is_blocked())
3397 return this->input_sections_blocker_;
3401 // We need to unlock FINAL_BLOCKER when finished.
3404 Write_after_input_sections_task::locks(Task_locker* tl)
3406 tl->add(this, this->final_blocker_);
3412 Write_after_input_sections_task::run(Workqueue*)
3414 this->layout_->write_sections_after_input_sections(this->of_);
3417 // Close_task_runner methods.
3419 // Run the task--close the file.
3422 Close_task_runner::run(Workqueue*, const Task*)
3424 // If we need to compute a checksum for the BUILD if, we do so here.
3425 this->layout_->write_build_id(this->of_);
3427 // If we've been asked to create a binary file, we do so here.
3428 if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
3429 this->layout_->write_binary(this->of_);
3434 // Instantiate the templates we need. We could use the configure
3435 // script to restrict this to only the ones for implemented targets.
3437 #ifdef HAVE_TARGET_32_LITTLE
3440 Layout::layout<32, false>(Sized_relobj<32, false>* object, unsigned int shndx,
3442 const elfcpp::Shdr<32, false>& shdr,
3443 unsigned int, unsigned int, off_t*);
3446 #ifdef HAVE_TARGET_32_BIG
3449 Layout::layout<32, true>(Sized_relobj<32, true>* object, unsigned int shndx,
3451 const elfcpp::Shdr<32, true>& shdr,
3452 unsigned int, unsigned int, off_t*);
3455 #ifdef HAVE_TARGET_64_LITTLE
3458 Layout::layout<64, false>(Sized_relobj<64, false>* object, unsigned int shndx,
3460 const elfcpp::Shdr<64, false>& shdr,
3461 unsigned int, unsigned int, off_t*);
3464 #ifdef HAVE_TARGET_64_BIG
3467 Layout::layout<64, true>(Sized_relobj<64, true>* object, unsigned int shndx,
3469 const elfcpp::Shdr<64, true>& shdr,
3470 unsigned int, unsigned int, off_t*);
3473 #ifdef HAVE_TARGET_32_LITTLE
3476 Layout::layout_reloc<32, false>(Sized_relobj<32, false>* object,
3477 unsigned int reloc_shndx,
3478 const elfcpp::Shdr<32, false>& shdr,
3479 Output_section* data_section,
3480 Relocatable_relocs* rr);
3483 #ifdef HAVE_TARGET_32_BIG
3486 Layout::layout_reloc<32, true>(Sized_relobj<32, true>* object,
3487 unsigned int reloc_shndx,
3488 const elfcpp::Shdr<32, true>& shdr,
3489 Output_section* data_section,
3490 Relocatable_relocs* rr);
3493 #ifdef HAVE_TARGET_64_LITTLE
3496 Layout::layout_reloc<64, false>(Sized_relobj<64, false>* object,
3497 unsigned int reloc_shndx,
3498 const elfcpp::Shdr<64, false>& shdr,
3499 Output_section* data_section,
3500 Relocatable_relocs* rr);
3503 #ifdef HAVE_TARGET_64_BIG
3506 Layout::layout_reloc<64, true>(Sized_relobj<64, true>* object,
3507 unsigned int reloc_shndx,
3508 const elfcpp::Shdr<64, true>& shdr,
3509 Output_section* data_section,
3510 Relocatable_relocs* rr);
3513 #ifdef HAVE_TARGET_32_LITTLE
3516 Layout::layout_group<32, false>(Symbol_table* symtab,
3517 Sized_relobj<32, false>* object,
3519 const char* group_section_name,
3520 const char* signature,
3521 const elfcpp::Shdr<32, false>& shdr,
3522 elfcpp::Elf_Word flags,
3523 std::vector<unsigned int>* shndxes);
3526 #ifdef HAVE_TARGET_32_BIG
3529 Layout::layout_group<32, true>(Symbol_table* symtab,
3530 Sized_relobj<32, true>* object,
3532 const char* group_section_name,
3533 const char* signature,
3534 const elfcpp::Shdr<32, true>& shdr,
3535 elfcpp::Elf_Word flags,
3536 std::vector<unsigned int>* shndxes);
3539 #ifdef HAVE_TARGET_64_LITTLE
3542 Layout::layout_group<64, false>(Symbol_table* symtab,
3543 Sized_relobj<64, false>* object,
3545 const char* group_section_name,
3546 const char* signature,
3547 const elfcpp::Shdr<64, false>& shdr,
3548 elfcpp::Elf_Word flags,
3549 std::vector<unsigned int>* shndxes);
3552 #ifdef HAVE_TARGET_64_BIG
3555 Layout::layout_group<64, true>(Symbol_table* symtab,
3556 Sized_relobj<64, true>* object,
3558 const char* group_section_name,
3559 const char* signature,
3560 const elfcpp::Shdr<64, true>& shdr,
3561 elfcpp::Elf_Word flags,
3562 std::vector<unsigned int>* shndxes);
3565 #ifdef HAVE_TARGET_32_LITTLE
3568 Layout::layout_eh_frame<32, false>(Sized_relobj<32, false>* object,
3569 const unsigned char* symbols,
3571 const unsigned char* symbol_names,
3572 off_t symbol_names_size,
3574 const elfcpp::Shdr<32, false>& shdr,
3575 unsigned int reloc_shndx,
3576 unsigned int reloc_type,
3580 #ifdef HAVE_TARGET_32_BIG
3583 Layout::layout_eh_frame<32, true>(Sized_relobj<32, true>* object,
3584 const unsigned char* symbols,
3586 const unsigned char* symbol_names,
3587 off_t symbol_names_size,
3589 const elfcpp::Shdr<32, true>& shdr,
3590 unsigned int reloc_shndx,
3591 unsigned int reloc_type,
3595 #ifdef HAVE_TARGET_64_LITTLE
3598 Layout::layout_eh_frame<64, false>(Sized_relobj<64, false>* object,
3599 const unsigned char* symbols,
3601 const unsigned char* symbol_names,
3602 off_t symbol_names_size,
3604 const elfcpp::Shdr<64, false>& shdr,
3605 unsigned int reloc_shndx,
3606 unsigned int reloc_type,
3610 #ifdef HAVE_TARGET_64_BIG
3613 Layout::layout_eh_frame<64, true>(Sized_relobj<64, true>* object,
3614 const unsigned char* symbols,
3616 const unsigned char* symbol_names,
3617 off_t symbol_names_size,
3619 const elfcpp::Shdr<64, true>& shdr,
3620 unsigned int reloc_shndx,
3621 unsigned int reloc_type,
3625 } // End namespace gold.