1 // layout.cc -- lay out output file sections for gold
3 // Copyright 2006, 2007, 2008 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.
30 #include "parameters.h"
33 #include "script-sections.h"
38 #include "compressed_output.h"
45 // Layout_task_runner methods.
47 // Lay out the sections. This is called after all the input objects
51 Layout_task_runner::run(Workqueue* workqueue, const Task* task)
53 off_t file_size = this->layout_->finalize(this->input_objects_,
58 // Now we know the final size of the output file and we know where
59 // each piece of information goes.
60 Output_file* of = new Output_file(parameters->options().output_file_name());
61 if (this->options_.oformat() != General_options::OBJECT_FORMAT_ELF)
62 of->set_is_temporary();
65 // Queue up the final set of tasks.
66 gold::queue_final_tasks(this->options_, this->input_objects_,
67 this->symtab_, this->layout_, workqueue, of);
72 Layout::Layout(const General_options& options, Script_options* script_options)
73 : options_(options), script_options_(script_options), namepool_(),
74 sympool_(), dynpool_(), signatures_(),
75 section_name_map_(), segment_list_(), section_list_(),
76 unattached_section_list_(), special_output_list_(),
77 section_headers_(NULL), tls_segment_(NULL), symtab_section_(NULL),
78 dynsym_section_(NULL), dynamic_section_(NULL), dynamic_data_(NULL),
79 eh_frame_section_(NULL), group_signatures_(), output_file_size_(-1),
80 input_requires_executable_stack_(false),
81 input_with_gnu_stack_note_(false),
82 input_without_gnu_stack_note_(false),
83 has_static_tls_(false),
84 any_postprocessing_sections_(false)
86 // Make space for more than enough segments for a typical file.
87 // This is just for efficiency--it's OK if we wind up needing more.
88 this->segment_list_.reserve(12);
90 // We expect two unattached Output_data objects: the file header and
91 // the segment headers.
92 this->special_output_list_.reserve(2);
95 // Hash a key we use to look up an output section mapping.
98 Layout::Hash_key::operator()(const Layout::Key& k) const
100 return k.first + k.second.first + k.second.second;
103 // Return whether PREFIX is a prefix of STR.
106 is_prefix_of(const char* prefix, const char* str)
108 return strncmp(prefix, str, strlen(prefix)) == 0;
111 // Returns whether the given section is in the list of
112 // debug-sections-used-by-some-version-of-gdb. Currently,
113 // we've checked versions of gdb up to and including 6.7.1.
115 static const char* gdb_sections[] =
117 // ".debug_aranges", // not used by gdb as of 6.7.1
123 // ".debug_pubnames", // not used by gdb as of 6.7.1
129 is_gdb_debug_section(const char* str)
131 // We can do this faster: binary search or a hashtable. But why bother?
132 for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
133 if (strcmp(str, gdb_sections[i]) == 0)
138 // Whether to include this section in the link.
140 template<int size, bool big_endian>
142 Layout::include_section(Sized_relobj<size, big_endian>*, const char* name,
143 const elfcpp::Shdr<size, big_endian>& shdr)
145 switch (shdr.get_sh_type())
147 case elfcpp::SHT_NULL:
148 case elfcpp::SHT_SYMTAB:
149 case elfcpp::SHT_DYNSYM:
150 case elfcpp::SHT_STRTAB:
151 case elfcpp::SHT_HASH:
152 case elfcpp::SHT_DYNAMIC:
153 case elfcpp::SHT_SYMTAB_SHNDX:
156 case elfcpp::SHT_RELA:
157 case elfcpp::SHT_REL:
158 case elfcpp::SHT_GROUP:
159 // If we are emitting relocations these should be handled
161 gold_assert(!parameters->options().relocatable()
162 && !parameters->options().emit_relocs());
165 case elfcpp::SHT_PROGBITS:
166 if (parameters->options().strip_debug()
167 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
169 // Debugging sections can only be recognized by name.
170 if (is_prefix_of(".debug", name)
171 || is_prefix_of(".gnu.linkonce.wi.", name)
172 || is_prefix_of(".line", name)
173 || is_prefix_of(".stab", name))
176 if (parameters->options().strip_debug_gdb()
177 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
179 // Debugging sections can only be recognized by name.
180 if (is_prefix_of(".debug", name)
181 && !is_gdb_debug_section(name))
191 // Return an output section named NAME, or NULL if there is none.
194 Layout::find_output_section(const char* name) const
196 for (Section_list::const_iterator p = this->section_list_.begin();
197 p != this->section_list_.end();
199 if (strcmp((*p)->name(), name) == 0)
204 // Return an output segment of type TYPE, with segment flags SET set
205 // and segment flags CLEAR clear. Return NULL if there is none.
208 Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
209 elfcpp::Elf_Word clear) const
211 for (Segment_list::const_iterator p = this->segment_list_.begin();
212 p != this->segment_list_.end();
214 if (static_cast<elfcpp::PT>((*p)->type()) == type
215 && ((*p)->flags() & set) == set
216 && ((*p)->flags() & clear) == 0)
221 // Return the output section to use for section NAME with type TYPE
222 // and section flags FLAGS. NAME must be canonicalized in the string
223 // pool, and NAME_KEY is the key.
226 Layout::get_output_section(const char* name, Stringpool::Key name_key,
227 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags)
229 const Key key(name_key, std::make_pair(type, flags));
230 const std::pair<Key, Output_section*> v(key, NULL);
231 std::pair<Section_name_map::iterator, bool> ins(
232 this->section_name_map_.insert(v));
235 return ins.first->second;
238 // This is the first time we've seen this name/type/flags
239 // combination. If the section has contents but no flags, then
240 // see whether we have an existing section with the same name.
241 // This is a workaround for cases where assembler code forgets
242 // to set section flags, and the GNU linker would simply pick an
243 // existing section with the same name. FIXME: Perhaps there
244 // should be an option to control this.
245 Output_section* os = NULL;
246 if (type == elfcpp::SHT_PROGBITS && flags == 0)
248 os = this->find_output_section(name);
249 if (os != NULL && os->type() != elfcpp::SHT_PROGBITS)
253 os = this->make_output_section(name, type, flags);
254 ins.first->second = os;
259 // Pick the output section to use for section NAME, in input file
260 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
261 // linker created section. ADJUST_NAME is true if we should apply the
262 // standard name mappings in Layout::output_section_name. This will
263 // return NULL if the input section should be discarded.
266 Layout::choose_output_section(const Relobj* relobj, const char* name,
267 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
270 // We should ignore some flags. FIXME: This will need some
271 // adjustment for ld -r.
272 flags &= ~ (elfcpp::SHF_INFO_LINK
273 | elfcpp::SHF_LINK_ORDER
276 | elfcpp::SHF_STRINGS);
278 if (this->script_options_->saw_sections_clause())
280 // We are using a SECTIONS clause, so the output section is
281 // chosen based only on the name.
283 Script_sections* ss = this->script_options_->script_sections();
284 const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
285 Output_section** output_section_slot;
286 name = ss->output_section_name(file_name, name, &output_section_slot);
289 // The SECTIONS clause says to discard this input section.
293 // If this is an orphan section--one not mentioned in the linker
294 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
295 // default processing below.
297 if (output_section_slot != NULL)
299 if (*output_section_slot != NULL)
300 return *output_section_slot;
302 // We don't put sections found in the linker script into
303 // SECTION_NAME_MAP_. That keeps us from getting confused
304 // if an orphan section is mapped to a section with the same
305 // name as one in the linker script.
307 name = this->namepool_.add(name, false, NULL);
309 Output_section* os = this->make_output_section(name, type, flags);
310 os->set_found_in_sections_clause();
311 *output_section_slot = os;
316 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
318 // Turn NAME from the name of the input section into the name of the
321 size_t len = strlen(name);
322 if (adjust_name && !parameters->options().relocatable())
323 name = Layout::output_section_name(name, &len);
325 Stringpool::Key name_key;
326 name = this->namepool_.add_with_length(name, len, true, &name_key);
328 // Find or make the output section. The output section is selected
329 // based on the section name, type, and flags.
330 return this->get_output_section(name, name_key, type, flags);
333 // Return the output section to use for input section SHNDX, with name
334 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
335 // index of a relocation section which applies to this section, or 0
336 // if none, or -1U if more than one. RELOC_TYPE is the type of the
337 // relocation section if there is one. Set *OFF to the offset of this
338 // input section without the output section. Return NULL if the
339 // section should be discarded. Set *OFF to -1 if the section
340 // contents should not be written directly to the output file, but
341 // will instead receive special handling.
343 template<int size, bool big_endian>
345 Layout::layout(Sized_relobj<size, big_endian>* object, unsigned int shndx,
346 const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
347 unsigned int reloc_shndx, unsigned int, off_t* off)
349 if (!this->include_section(object, name, shdr))
354 // In a relocatable link a grouped section must not be combined with
355 // any other sections.
356 if (parameters->options().relocatable()
357 && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
359 name = this->namepool_.add(name, true, NULL);
360 os = this->make_output_section(name, shdr.get_sh_type(),
361 shdr.get_sh_flags());
365 os = this->choose_output_section(object, name, shdr.get_sh_type(),
366 shdr.get_sh_flags(), true);
371 // FIXME: Handle SHF_LINK_ORDER somewhere.
373 *off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
374 this->script_options_->saw_sections_clause());
379 // Handle a relocation section when doing a relocatable link.
381 template<int size, bool big_endian>
383 Layout::layout_reloc(Sized_relobj<size, big_endian>* object,
385 const elfcpp::Shdr<size, big_endian>& shdr,
386 Output_section* data_section,
387 Relocatable_relocs* rr)
389 gold_assert(parameters->options().relocatable()
390 || parameters->options().emit_relocs());
392 int sh_type = shdr.get_sh_type();
395 if (sh_type == elfcpp::SHT_REL)
397 else if (sh_type == elfcpp::SHT_RELA)
401 name += data_section->name();
403 Output_section* os = this->choose_output_section(object, name.c_str(),
408 os->set_should_link_to_symtab();
409 os->set_info_section(data_section);
411 Output_section_data* posd;
412 if (sh_type == elfcpp::SHT_REL)
414 os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
415 posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
419 else if (sh_type == elfcpp::SHT_RELA)
421 os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
422 posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
429 os->add_output_section_data(posd);
430 rr->set_output_data(posd);
435 // Handle a group section when doing a relocatable link.
437 template<int size, bool big_endian>
439 Layout::layout_group(Symbol_table* symtab,
440 Sized_relobj<size, big_endian>* object,
442 const char* group_section_name,
443 const char* signature,
444 const elfcpp::Shdr<size, big_endian>& shdr,
445 const elfcpp::Elf_Word* contents)
447 gold_assert(parameters->options().relocatable());
448 gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
449 group_section_name = this->namepool_.add(group_section_name, true, NULL);
450 Output_section* os = this->make_output_section(group_section_name,
452 shdr.get_sh_flags());
454 // We need to find a symbol with the signature in the symbol table.
455 // If we don't find one now, we need to look again later.
456 Symbol* sym = symtab->lookup(signature, NULL);
458 os->set_info_symndx(sym);
461 // We will wind up using a symbol whose name is the signature.
462 // So just put the signature in the symbol name pool to save it.
463 signature = symtab->canonicalize_name(signature);
464 this->group_signatures_.push_back(Group_signature(os, signature));
467 os->set_should_link_to_symtab();
470 section_size_type entry_count =
471 convert_to_section_size_type(shdr.get_sh_size() / 4);
472 Output_section_data* posd =
473 new Output_data_group<size, big_endian>(object, entry_count, contents);
474 os->add_output_section_data(posd);
477 // Special GNU handling of sections name .eh_frame. They will
478 // normally hold exception frame data as defined by the C++ ABI
479 // (http://codesourcery.com/cxx-abi/).
481 template<int size, bool big_endian>
483 Layout::layout_eh_frame(Sized_relobj<size, big_endian>* object,
484 const unsigned char* symbols,
486 const unsigned char* symbol_names,
487 off_t symbol_names_size,
489 const elfcpp::Shdr<size, big_endian>& shdr,
490 unsigned int reloc_shndx, unsigned int reloc_type,
493 gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS);
494 gold_assert(shdr.get_sh_flags() == elfcpp::SHF_ALLOC);
496 const char* const name = ".eh_frame";
497 Output_section* os = this->choose_output_section(object,
499 elfcpp::SHT_PROGBITS,
505 if (this->eh_frame_section_ == NULL)
507 this->eh_frame_section_ = os;
508 this->eh_frame_data_ = new Eh_frame();
509 os->add_output_section_data(this->eh_frame_data_);
511 if (this->options_.eh_frame_hdr())
513 Output_section* hdr_os =
514 this->choose_output_section(NULL,
516 elfcpp::SHT_PROGBITS,
522 Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
523 this->eh_frame_data_);
524 hdr_os->add_output_section_data(hdr_posd);
526 hdr_os->set_after_input_sections();
528 if (!this->script_options_->saw_phdrs_clause())
530 Output_segment* hdr_oseg;
531 hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
533 hdr_oseg->add_output_section(hdr_os, elfcpp::PF_R);
536 this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
541 gold_assert(this->eh_frame_section_ == os);
543 if (this->eh_frame_data_->add_ehframe_input_section(object,
554 // We couldn't handle this .eh_frame section for some reason.
555 // Add it as a normal section.
556 bool saw_sections_clause = this->script_options_->saw_sections_clause();
557 *off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
558 saw_sections_clause);
564 // Add POSD to an output section using NAME, TYPE, and FLAGS.
567 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
568 elfcpp::Elf_Xword flags,
569 Output_section_data* posd)
571 Output_section* os = this->choose_output_section(NULL, name, type, flags,
574 os->add_output_section_data(posd);
577 // Map section flags to segment flags.
580 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
582 elfcpp::Elf_Word ret = elfcpp::PF_R;
583 if ((flags & elfcpp::SHF_WRITE) != 0)
585 if ((flags & elfcpp::SHF_EXECINSTR) != 0)
590 // Sometimes we compress sections. This is typically done for
591 // sections that are not part of normal program execution (such as
592 // .debug_* sections), and where the readers of these sections know
593 // how to deal with compressed sections. (To make it easier for them,
594 // we will rename the ouput section in such cases from .foo to
595 // .foo.zlib.nnnn, where nnnn is the uncompressed size.) This routine
596 // doesn't say for certain whether we'll compress -- it depends on
597 // commandline options as well -- just whether this section is a
598 // candidate for compression.
601 is_compressible_debug_section(const char* secname)
603 return (strncmp(secname, ".debug", sizeof(".debug") - 1) == 0);
606 // Make a new Output_section, and attach it to segments as
610 Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
611 elfcpp::Elf_Xword flags)
614 if ((flags & elfcpp::SHF_ALLOC) == 0
615 && this->options_.compress_debug_sections()
616 && is_compressible_debug_section(name))
617 os = new Output_compressed_section(&this->options_, name, type, flags);
619 os = new Output_section(name, type, flags);
621 this->section_list_.push_back(os);
623 if ((flags & elfcpp::SHF_ALLOC) == 0)
624 this->unattached_section_list_.push_back(os);
627 if (parameters->options().relocatable())
630 // If we have a SECTIONS clause, we can't handle the attachment
631 // to segments until after we've seen all the sections.
632 if (this->script_options_->saw_sections_clause())
635 gold_assert(!this->script_options_->saw_phdrs_clause());
637 // This output section goes into a PT_LOAD segment.
639 elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
641 // In general the only thing we really care about for PT_LOAD
642 // segments is whether or not they are writable, so that is how
643 // we search for them. People who need segments sorted on some
644 // other basis will have to use a linker script.
646 Segment_list::const_iterator p;
647 for (p = this->segment_list_.begin();
648 p != this->segment_list_.end();
651 if ((*p)->type() == elfcpp::PT_LOAD
652 && ((*p)->flags() & elfcpp::PF_W) == (seg_flags & elfcpp::PF_W))
654 // If -Tbss was specified, we need to separate the data
656 if (this->options_.user_set_Tbss())
658 if ((type == elfcpp::SHT_NOBITS)
659 == (*p)->has_any_data_sections())
663 (*p)->add_output_section(os, seg_flags);
668 if (p == this->segment_list_.end())
670 Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
672 oseg->add_output_section(os, seg_flags);
675 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
677 if (type == elfcpp::SHT_NOTE)
679 // See if we already have an equivalent PT_NOTE segment.
680 for (p = this->segment_list_.begin();
681 p != segment_list_.end();
684 if ((*p)->type() == elfcpp::PT_NOTE
685 && (((*p)->flags() & elfcpp::PF_W)
686 == (seg_flags & elfcpp::PF_W)))
688 (*p)->add_output_section(os, seg_flags);
693 if (p == this->segment_list_.end())
695 Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
697 oseg->add_output_section(os, seg_flags);
701 // If we see a loadable SHF_TLS section, we create a PT_TLS
702 // segment. There can only be one such segment.
703 if ((flags & elfcpp::SHF_TLS) != 0)
705 if (this->tls_segment_ == NULL)
706 this->tls_segment_ = this->make_output_segment(elfcpp::PT_TLS,
708 this->tls_segment_->add_output_section(os, seg_flags);
715 // Make an output section for a script.
718 Layout::make_output_section_for_script(const char* name)
720 name = this->namepool_.add(name, false, NULL);
721 Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
723 os->set_found_in_sections_clause();
727 // Return the number of segments we expect to see.
730 Layout::expected_segment_count() const
732 size_t ret = this->segment_list_.size();
734 // If we didn't see a SECTIONS clause in a linker script, we should
735 // already have the complete list of segments. Otherwise we ask the
736 // SECTIONS clause how many segments it expects, and add in the ones
737 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
739 if (!this->script_options_->saw_sections_clause())
743 const Script_sections* ss = this->script_options_->script_sections();
744 return ret + ss->expected_segment_count(this);
748 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
749 // is whether we saw a .note.GNU-stack section in the object file.
750 // GNU_STACK_FLAGS is the section flags. The flags give the
751 // protection required for stack memory. We record this in an
752 // executable as a PT_GNU_STACK segment. If an object file does not
753 // have a .note.GNU-stack segment, we must assume that it is an old
754 // object. On some targets that will force an executable stack.
757 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags)
760 this->input_without_gnu_stack_note_ = true;
763 this->input_with_gnu_stack_note_ = true;
764 if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
765 this->input_requires_executable_stack_ = true;
769 // Create the dynamic sections which are needed before we read the
773 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
775 if (parameters->doing_static_link())
778 this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
781 | elfcpp::SHF_WRITE),
784 symtab->define_in_output_data("_DYNAMIC", NULL, this->dynamic_section_, 0, 0,
785 elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
786 elfcpp::STV_HIDDEN, 0, false, false);
788 this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_);
790 this->dynamic_section_->add_output_section_data(this->dynamic_data_);
793 // For each output section whose name can be represented as C symbol,
794 // define __start and __stop symbols for the section. This is a GNU
798 Layout::define_section_symbols(Symbol_table* symtab)
800 for (Section_list::const_iterator p = this->section_list_.begin();
801 p != this->section_list_.end();
804 const char* const name = (*p)->name();
805 if (name[strspn(name,
807 "ABCDEFGHIJKLMNOPWRSTUVWXYZ"
808 "abcdefghijklmnopqrstuvwxyz"
812 const std::string name_string(name);
813 const std::string start_name("__start_" + name_string);
814 const std::string stop_name("__stop_" + name_string);
816 symtab->define_in_output_data(start_name.c_str(),
825 false, // offset_is_from_end
826 true); // only_if_ref
828 symtab->define_in_output_data(stop_name.c_str(),
837 true, // offset_is_from_end
838 true); // only_if_ref
843 // Define symbols for group signatures.
846 Layout::define_group_signatures(Symbol_table* symtab)
848 for (Group_signatures::iterator p = this->group_signatures_.begin();
849 p != this->group_signatures_.end();
852 Symbol* sym = symtab->lookup(p->signature, NULL);
854 p->section->set_info_symndx(sym);
857 // Force the name of the group section to the group
858 // signature, and use the group's section symbol as the
860 if (strcmp(p->section->name(), p->signature) != 0)
862 const char* name = this->namepool_.add(p->signature,
864 p->section->set_name(name);
866 p->section->set_needs_symtab_index();
867 p->section->set_info_section_symndx(p->section);
871 this->group_signatures_.clear();
874 // Find the first read-only PT_LOAD segment, creating one if
878 Layout::find_first_load_seg()
880 for (Segment_list::const_iterator p = this->segment_list_.begin();
881 p != this->segment_list_.end();
884 if ((*p)->type() == elfcpp::PT_LOAD
885 && ((*p)->flags() & elfcpp::PF_R) != 0
886 && ((*p)->flags() & elfcpp::PF_W) == 0)
890 gold_assert(!this->script_options_->saw_phdrs_clause());
892 Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
897 // Finalize the layout. When this is called, we have created all the
898 // output sections and all the output segments which are based on
899 // input sections. We have several things to do, and we have to do
900 // them in the right order, so that we get the right results correctly
903 // 1) Finalize the list of output segments and create the segment
906 // 2) Finalize the dynamic symbol table and associated sections.
908 // 3) Determine the final file offset of all the output segments.
910 // 4) Determine the final file offset of all the SHF_ALLOC output
913 // 5) Create the symbol table sections and the section name table
916 // 6) Finalize the symbol table: set symbol values to their final
917 // value and make a final determination of which symbols are going
918 // into the output symbol table.
920 // 7) Create the section table header.
922 // 8) Determine the final file offset of all the output sections which
923 // are not SHF_ALLOC, including the section table header.
925 // 9) Finalize the ELF file header.
927 // This function returns the size of the output file.
930 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
931 Target* target, const Task* task)
933 target->finalize_sections(this);
935 this->count_local_symbols(task, input_objects);
937 this->create_gold_note();
938 this->create_executable_stack_info(target);
940 Output_segment* phdr_seg = NULL;
941 if (!parameters->options().relocatable() && !parameters->doing_static_link())
943 // There was a dynamic object in the link. We need to create
944 // some information for the dynamic linker.
946 // Create the PT_PHDR segment which will hold the program
948 if (!this->script_options_->saw_phdrs_clause())
949 phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
951 // Create the dynamic symbol table, including the hash table.
952 Output_section* dynstr;
953 std::vector<Symbol*> dynamic_symbols;
954 unsigned int local_dynamic_count;
955 Versions versions(*this->script_options()->version_script_info(),
957 this->create_dynamic_symtab(input_objects, symtab, &dynstr,
958 &local_dynamic_count, &dynamic_symbols,
961 // Create the .interp section to hold the name of the
962 // interpreter, and put it in a PT_INTERP segment.
963 if (!parameters->options().shared())
964 this->create_interp(target);
966 // Finish the .dynamic section to hold the dynamic data, and put
967 // it in a PT_DYNAMIC segment.
968 this->finish_dynamic_section(input_objects, symtab);
970 // We should have added everything we need to the dynamic string
972 this->dynpool_.set_string_offsets();
974 // Create the version sections. We can't do this until the
975 // dynamic string table is complete.
976 this->create_version_sections(&versions, symtab, local_dynamic_count,
977 dynamic_symbols, dynstr);
980 // If there is a SECTIONS clause, put all the input sections into
981 // the required order.
982 Output_segment* load_seg;
983 if (this->script_options_->saw_sections_clause())
984 load_seg = this->set_section_addresses_from_script(symtab);
985 else if (parameters->options().relocatable())
988 load_seg = this->find_first_load_seg();
990 if (this->options_.oformat() != General_options::OBJECT_FORMAT_ELF)
993 gold_assert(phdr_seg == NULL || load_seg != NULL);
995 // Lay out the segment headers.
996 Output_segment_headers* segment_headers;
997 if (parameters->options().relocatable())
998 segment_headers = NULL;
1001 segment_headers = new Output_segment_headers(this->segment_list_);
1002 if (load_seg != NULL)
1003 load_seg->add_initial_output_data(segment_headers);
1004 if (phdr_seg != NULL)
1005 phdr_seg->add_initial_output_data(segment_headers);
1008 // Lay out the file header.
1009 Output_file_header* file_header;
1010 file_header = new Output_file_header(target, symtab, segment_headers,
1011 this->options_.entry());
1012 if (load_seg != NULL)
1013 load_seg->add_initial_output_data(file_header);
1015 this->special_output_list_.push_back(file_header);
1016 if (segment_headers != NULL)
1017 this->special_output_list_.push_back(segment_headers);
1019 if (this->script_options_->saw_phdrs_clause()
1020 && !parameters->options().relocatable())
1022 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
1023 // clause in a linker script.
1024 Script_sections* ss = this->script_options_->script_sections();
1025 ss->put_headers_in_phdrs(file_header, segment_headers);
1028 // We set the output section indexes in set_segment_offsets and
1029 // set_section_indexes.
1030 unsigned int shndx = 1;
1032 // Set the file offsets of all the segments, and all the sections
1035 if (!parameters->options().relocatable())
1036 off = this->set_segment_offsets(target, load_seg, &shndx);
1038 off = this->set_relocatable_section_offsets(file_header, &shndx);
1040 // Set the file offsets of all the non-data sections we've seen so
1041 // far which don't have to wait for the input sections. We need
1042 // this in order to finalize local symbols in non-allocated
1044 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1046 // Create the symbol table sections.
1047 this->create_symtab_sections(input_objects, symtab, &off);
1048 if (!parameters->doing_static_link())
1049 this->assign_local_dynsym_offsets(input_objects);
1051 // Process any symbol assignments from a linker script. This must
1052 // be called after the symbol table has been finalized.
1053 this->script_options_->finalize_symbols(symtab, this);
1055 // Create the .shstrtab section.
1056 Output_section* shstrtab_section = this->create_shstrtab();
1058 // Set the file offsets of the rest of the non-data sections which
1059 // don't have to wait for the input sections.
1060 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1062 // Now that all sections have been created, set the section indexes.
1063 shndx = this->set_section_indexes(shndx);
1065 // Create the section table header.
1066 this->create_shdrs(&off);
1068 // If there are no sections which require postprocessing, we can
1069 // handle the section names now, and avoid a resize later.
1070 if (!this->any_postprocessing_sections_)
1071 off = this->set_section_offsets(off,
1072 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
1074 file_header->set_section_info(this->section_headers_, shstrtab_section);
1076 // Now we know exactly where everything goes in the output file
1077 // (except for non-allocated sections which require postprocessing).
1078 Output_data::layout_complete();
1080 this->output_file_size_ = off;
1085 // Create a .note section for an executable or shared library. This
1086 // records the version of gold used to create the binary.
1089 Layout::create_gold_note()
1091 if (parameters->options().relocatable())
1094 // Authorities all agree that the values in a .note field should
1095 // be aligned on 4-byte boundaries for 32-bit binaries. However,
1096 // they differ on what the alignment is for 64-bit binaries.
1097 // The GABI says unambiguously they take 8-byte alignment:
1098 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
1099 // Other documentation says alignment should always be 4 bytes:
1100 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
1101 // GNU ld and GNU readelf both support the latter (at least as of
1102 // version 2.16.91), and glibc always generates the latter for
1103 // .note.ABI-tag (as of version 1.6), so that's the one we go with
1105 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
1106 const int size = parameters->target().get_size();
1108 const int size = 32;
1111 // The contents of the .note section.
1112 const char* name = "GNU";
1113 std::string desc(std::string("gold ") + gold::get_version_string());
1114 size_t namesz = strlen(name) + 1;
1115 size_t aligned_namesz = align_address(namesz, size / 8);
1116 size_t descsz = desc.length() + 1;
1117 size_t aligned_descsz = align_address(descsz, size / 8);
1118 const int note_type = 4;
1120 size_t notesz = 3 * (size / 8) + aligned_namesz + aligned_descsz;
1122 unsigned char buffer[128];
1123 gold_assert(sizeof buffer >= notesz);
1124 memset(buffer, 0, notesz);
1126 bool is_big_endian = parameters->target().is_big_endian();
1132 elfcpp::Swap<32, false>::writeval(buffer, namesz);
1133 elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
1134 elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
1138 elfcpp::Swap<32, true>::writeval(buffer, namesz);
1139 elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
1140 elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
1143 else if (size == 64)
1147 elfcpp::Swap<64, false>::writeval(buffer, namesz);
1148 elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
1149 elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
1153 elfcpp::Swap<64, true>::writeval(buffer, namesz);
1154 elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
1155 elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
1161 memcpy(buffer + 3 * (size / 8), name, namesz);
1162 memcpy(buffer + 3 * (size / 8) + aligned_namesz, desc.data(), descsz);
1164 const char* note_name = this->namepool_.add(".note", false, NULL);
1165 Output_section* os = this->make_output_section(note_name,
1168 Output_section_data* posd = new Output_data_const(buffer, notesz,
1170 os->add_output_section_data(posd);
1173 // Record whether the stack should be executable. This can be set
1174 // from the command line using the -z execstack or -z noexecstack
1175 // options. Otherwise, if any input file has a .note.GNU-stack
1176 // section with the SHF_EXECINSTR flag set, the stack should be
1177 // executable. Otherwise, if at least one input file a
1178 // .note.GNU-stack section, and some input file has no .note.GNU-stack
1179 // section, we use the target default for whether the stack should be
1180 // executable. Otherwise, we don't generate a stack note. When
1181 // generating a object file, we create a .note.GNU-stack section with
1182 // the appropriate marking. When generating an executable or shared
1183 // library, we create a PT_GNU_STACK segment.
1186 Layout::create_executable_stack_info(const Target* target)
1188 bool is_stack_executable;
1189 if (this->options_.is_execstack_set())
1190 is_stack_executable = this->options_.is_stack_executable();
1191 else if (!this->input_with_gnu_stack_note_)
1195 if (this->input_requires_executable_stack_)
1196 is_stack_executable = true;
1197 else if (this->input_without_gnu_stack_note_)
1198 is_stack_executable = target->is_default_stack_executable();
1200 is_stack_executable = false;
1203 if (parameters->options().relocatable())
1205 const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
1206 elfcpp::Elf_Xword flags = 0;
1207 if (is_stack_executable)
1208 flags |= elfcpp::SHF_EXECINSTR;
1209 this->make_output_section(name, elfcpp::SHT_PROGBITS, flags);
1213 if (this->script_options_->saw_phdrs_clause())
1215 int flags = elfcpp::PF_R | elfcpp::PF_W;
1216 if (is_stack_executable)
1217 flags |= elfcpp::PF_X;
1218 this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
1222 // Return whether SEG1 should be before SEG2 in the output file. This
1223 // is based entirely on the segment type and flags. When this is
1224 // called the segment addresses has normally not yet been set.
1227 Layout::segment_precedes(const Output_segment* seg1,
1228 const Output_segment* seg2)
1230 elfcpp::Elf_Word type1 = seg1->type();
1231 elfcpp::Elf_Word type2 = seg2->type();
1233 // The single PT_PHDR segment is required to precede any loadable
1234 // segment. We simply make it always first.
1235 if (type1 == elfcpp::PT_PHDR)
1237 gold_assert(type2 != elfcpp::PT_PHDR);
1240 if (type2 == elfcpp::PT_PHDR)
1243 // The single PT_INTERP segment is required to precede any loadable
1244 // segment. We simply make it always second.
1245 if (type1 == elfcpp::PT_INTERP)
1247 gold_assert(type2 != elfcpp::PT_INTERP);
1250 if (type2 == elfcpp::PT_INTERP)
1253 // We then put PT_LOAD segments before any other segments.
1254 if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
1256 if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
1259 // We put the PT_TLS segment last, because that is where the dynamic
1260 // linker expects to find it (this is just for efficiency; other
1261 // positions would also work correctly).
1262 if (type1 == elfcpp::PT_TLS && type2 != elfcpp::PT_TLS)
1264 if (type2 == elfcpp::PT_TLS && type1 != elfcpp::PT_TLS)
1267 const elfcpp::Elf_Word flags1 = seg1->flags();
1268 const elfcpp::Elf_Word flags2 = seg2->flags();
1270 // The order of non-PT_LOAD segments is unimportant. We simply sort
1271 // by the numeric segment type and flags values. There should not
1272 // be more than one segment with the same type and flags.
1273 if (type1 != elfcpp::PT_LOAD)
1276 return type1 < type2;
1277 gold_assert(flags1 != flags2);
1278 return flags1 < flags2;
1281 // If the addresses are set already, sort by load address.
1282 if (seg1->are_addresses_set())
1284 if (!seg2->are_addresses_set())
1287 unsigned int section_count1 = seg1->output_section_count();
1288 unsigned int section_count2 = seg2->output_section_count();
1289 if (section_count1 == 0 && section_count2 > 0)
1291 if (section_count1 > 0 && section_count2 == 0)
1294 uint64_t paddr1 = seg1->first_section_load_address();
1295 uint64_t paddr2 = seg2->first_section_load_address();
1296 if (paddr1 != paddr2)
1297 return paddr1 < paddr2;
1299 else if (seg2->are_addresses_set())
1302 // We sort PT_LOAD segments based on the flags. Readonly segments
1303 // come before writable segments. Then writable segments with data
1304 // come before writable segments without data. Then executable
1305 // segments come before non-executable segments. Then the unlikely
1306 // case of a non-readable segment comes before the normal case of a
1307 // readable segment. If there are multiple segments with the same
1308 // type and flags, we require that the address be set, and we sort
1309 // by virtual address and then physical address.
1310 if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
1311 return (flags1 & elfcpp::PF_W) == 0;
1312 if ((flags1 & elfcpp::PF_W) != 0
1313 && seg1->has_any_data_sections() != seg2->has_any_data_sections())
1314 return seg1->has_any_data_sections();
1315 if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
1316 return (flags1 & elfcpp::PF_X) != 0;
1317 if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
1318 return (flags1 & elfcpp::PF_R) == 0;
1320 // We shouldn't get here--we shouldn't create segments which we
1321 // can't distinguish.
1325 // Set the file offsets of all the segments, and all the sections they
1326 // contain. They have all been created. LOAD_SEG must be be laid out
1327 // first. Return the offset of the data to follow.
1330 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
1331 unsigned int *pshndx)
1333 // Sort them into the final order.
1334 std::sort(this->segment_list_.begin(), this->segment_list_.end(),
1335 Layout::Compare_segments());
1337 // Find the PT_LOAD segments, and set their addresses and offsets
1338 // and their section's addresses and offsets.
1340 if (this->options_.user_set_Ttext())
1341 addr = this->options_.Ttext();
1342 else if (parameters->options().shared())
1345 addr = target->default_text_segment_address();
1348 // If LOAD_SEG is NULL, then the file header and segment headers
1349 // will not be loadable. But they still need to be at offset 0 in
1350 // the file. Set their offsets now.
1351 if (load_seg == NULL)
1353 for (Data_list::iterator p = this->special_output_list_.begin();
1354 p != this->special_output_list_.end();
1357 off = align_address(off, (*p)->addralign());
1358 (*p)->set_address_and_file_offset(0, off);
1359 off += (*p)->data_size();
1363 bool was_readonly = false;
1364 for (Segment_list::iterator p = this->segment_list_.begin();
1365 p != this->segment_list_.end();
1368 if ((*p)->type() == elfcpp::PT_LOAD)
1370 if (load_seg != NULL && load_seg != *p)
1374 bool are_addresses_set = (*p)->are_addresses_set();
1375 if (are_addresses_set)
1377 // When it comes to setting file offsets, we care about
1378 // the physical address.
1379 addr = (*p)->paddr();
1381 else if (this->options_.user_set_Tdata()
1382 && ((*p)->flags() & elfcpp::PF_W) != 0
1383 && (!this->options_.user_set_Tbss()
1384 || (*p)->has_any_data_sections()))
1386 addr = this->options_.Tdata();
1387 are_addresses_set = true;
1389 else if (this->options_.user_set_Tbss()
1390 && ((*p)->flags() & elfcpp::PF_W) != 0
1391 && !(*p)->has_any_data_sections())
1393 addr = this->options_.Tbss();
1394 are_addresses_set = true;
1397 uint64_t orig_addr = addr;
1398 uint64_t orig_off = off;
1400 uint64_t aligned_addr = 0;
1401 uint64_t abi_pagesize = target->abi_pagesize();
1403 // FIXME: This should depend on the -n and -N options.
1404 (*p)->set_minimum_p_align(target->common_pagesize());
1406 if (are_addresses_set)
1408 // Adjust the file offset to the same address modulo the
1410 uint64_t unsigned_off = off;
1411 uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
1412 | (addr & (abi_pagesize - 1)));
1413 if (aligned_off < unsigned_off)
1414 aligned_off += abi_pagesize;
1419 // If the last segment was readonly, and this one is
1420 // not, then skip the address forward one page,
1421 // maintaining the same position within the page. This
1422 // lets us store both segments overlapping on a single
1423 // page in the file, but the loader will put them on
1424 // different pages in memory.
1426 addr = align_address(addr, (*p)->maximum_alignment());
1427 aligned_addr = addr;
1429 if (was_readonly && ((*p)->flags() & elfcpp::PF_W) != 0)
1431 if ((addr & (abi_pagesize - 1)) != 0)
1432 addr = addr + abi_pagesize;
1435 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
1438 unsigned int shndx_hold = *pshndx;
1439 uint64_t new_addr = (*p)->set_section_addresses(false, addr, &off,
1442 // Now that we know the size of this segment, we may be able
1443 // to save a page in memory, at the cost of wasting some
1444 // file space, by instead aligning to the start of a new
1445 // page. Here we use the real machine page size rather than
1446 // the ABI mandated page size.
1448 if (!are_addresses_set && aligned_addr != addr)
1450 uint64_t common_pagesize = target->common_pagesize();
1451 uint64_t first_off = (common_pagesize
1453 & (common_pagesize - 1)));
1454 uint64_t last_off = new_addr & (common_pagesize - 1);
1457 && ((aligned_addr & ~ (common_pagesize - 1))
1458 != (new_addr & ~ (common_pagesize - 1)))
1459 && first_off + last_off <= common_pagesize)
1461 *pshndx = shndx_hold;
1462 addr = align_address(aligned_addr, common_pagesize);
1463 addr = align_address(addr, (*p)->maximum_alignment());
1464 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
1465 new_addr = (*p)->set_section_addresses(true, addr, &off,
1472 if (((*p)->flags() & elfcpp::PF_W) == 0)
1473 was_readonly = true;
1477 // Handle the non-PT_LOAD segments, setting their offsets from their
1478 // section's offsets.
1479 for (Segment_list::iterator p = this->segment_list_.begin();
1480 p != this->segment_list_.end();
1483 if ((*p)->type() != elfcpp::PT_LOAD)
1487 // Set the TLS offsets for each section in the PT_TLS segment.
1488 if (this->tls_segment_ != NULL)
1489 this->tls_segment_->set_tls_offsets();
1494 // Set the offsets of all the allocated sections when doing a
1495 // relocatable link. This does the same jobs as set_segment_offsets,
1496 // only for a relocatable link.
1499 Layout::set_relocatable_section_offsets(Output_data* file_header,
1500 unsigned int *pshndx)
1504 file_header->set_address_and_file_offset(0, 0);
1505 off += file_header->data_size();
1507 for (Section_list::iterator p = this->section_list_.begin();
1508 p != this->section_list_.end();
1511 // We skip unallocated sections here, except that group sections
1512 // have to come first.
1513 if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
1514 && (*p)->type() != elfcpp::SHT_GROUP)
1517 off = align_address(off, (*p)->addralign());
1519 // The linker script might have set the address.
1520 if (!(*p)->is_address_valid())
1521 (*p)->set_address(0);
1522 (*p)->set_file_offset(off);
1523 (*p)->finalize_data_size();
1524 off += (*p)->data_size();
1526 (*p)->set_out_shndx(*pshndx);
1533 // Set the file offset of all the sections not associated with a
1537 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
1539 for (Section_list::iterator p = this->unattached_section_list_.begin();
1540 p != this->unattached_section_list_.end();
1543 // The symtab section is handled in create_symtab_sections.
1544 if (*p == this->symtab_section_)
1547 // If we've already set the data size, don't set it again.
1548 if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
1551 if (pass == BEFORE_INPUT_SECTIONS_PASS
1552 && (*p)->requires_postprocessing())
1554 (*p)->create_postprocessing_buffer();
1555 this->any_postprocessing_sections_ = true;
1558 if (pass == BEFORE_INPUT_SECTIONS_PASS
1559 && (*p)->after_input_sections())
1561 else if (pass == POSTPROCESSING_SECTIONS_PASS
1562 && (!(*p)->after_input_sections()
1563 || (*p)->type() == elfcpp::SHT_STRTAB))
1565 else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
1566 && (!(*p)->after_input_sections()
1567 || (*p)->type() != elfcpp::SHT_STRTAB))
1570 off = align_address(off, (*p)->addralign());
1571 (*p)->set_file_offset(off);
1572 (*p)->finalize_data_size();
1573 off += (*p)->data_size();
1575 // At this point the name must be set.
1576 if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
1577 this->namepool_.add((*p)->name(), false, NULL);
1582 // Set the section indexes of all the sections not associated with a
1586 Layout::set_section_indexes(unsigned int shndx)
1588 const bool output_is_object = parameters->options().relocatable();
1589 for (Section_list::iterator p = this->unattached_section_list_.begin();
1590 p != this->unattached_section_list_.end();
1593 // In a relocatable link, we already did group sections.
1594 if (output_is_object
1595 && (*p)->type() == elfcpp::SHT_GROUP)
1598 (*p)->set_out_shndx(shndx);
1604 // Set the section addresses according to the linker script. This is
1605 // only called when we see a SECTIONS clause. This returns the
1606 // program segment which should hold the file header and segment
1607 // headers, if any. It will return NULL if they should not be in a
1611 Layout::set_section_addresses_from_script(Symbol_table* symtab)
1613 Script_sections* ss = this->script_options_->script_sections();
1614 gold_assert(ss->saw_sections_clause());
1616 // Place each orphaned output section in the script.
1617 for (Section_list::iterator p = this->section_list_.begin();
1618 p != this->section_list_.end();
1621 if (!(*p)->found_in_sections_clause())
1622 ss->place_orphan(*p);
1625 return this->script_options_->set_section_addresses(symtab, this);
1628 // Count the local symbols in the regular symbol table and the dynamic
1629 // symbol table, and build the respective string pools.
1632 Layout::count_local_symbols(const Task* task,
1633 const Input_objects* input_objects)
1635 // First, figure out an upper bound on the number of symbols we'll
1636 // be inserting into each pool. This helps us create the pools with
1637 // the right size, to avoid unnecessary hashtable resizing.
1638 unsigned int symbol_count = 0;
1639 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1640 p != input_objects->relobj_end();
1642 symbol_count += (*p)->local_symbol_count();
1644 // Go from "upper bound" to "estimate." We overcount for two
1645 // reasons: we double-count symbols that occur in more than one
1646 // object file, and we count symbols that are dropped from the
1647 // output. Add it all together and assume we overcount by 100%.
1650 // We assume all symbols will go into both the sympool and dynpool.
1651 this->sympool_.reserve(symbol_count);
1652 this->dynpool_.reserve(symbol_count);
1654 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1655 p != input_objects->relobj_end();
1658 Task_lock_obj<Object> tlo(task, *p);
1659 (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
1663 // Create the symbol table sections. Here we also set the final
1664 // values of the symbols. At this point all the loadable sections are
1668 Layout::create_symtab_sections(const Input_objects* input_objects,
1669 Symbol_table* symtab,
1674 if (parameters->target().get_size() == 32)
1676 symsize = elfcpp::Elf_sizes<32>::sym_size;
1679 else if (parameters->target().get_size() == 64)
1681 symsize = elfcpp::Elf_sizes<64>::sym_size;
1688 off = align_address(off, align);
1689 off_t startoff = off;
1691 // Save space for the dummy symbol at the start of the section. We
1692 // never bother to write this out--it will just be left as zero.
1694 unsigned int local_symbol_index = 1;
1696 // Add STT_SECTION symbols for each Output section which needs one.
1697 for (Section_list::iterator p = this->section_list_.begin();
1698 p != this->section_list_.end();
1701 if (!(*p)->needs_symtab_index())
1702 (*p)->set_symtab_index(-1U);
1705 (*p)->set_symtab_index(local_symbol_index);
1706 ++local_symbol_index;
1711 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1712 p != input_objects->relobj_end();
1715 unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
1717 off += (index - local_symbol_index) * symsize;
1718 local_symbol_index = index;
1721 unsigned int local_symcount = local_symbol_index;
1722 gold_assert(local_symcount * symsize == off - startoff);
1725 size_t dyn_global_index;
1727 if (this->dynsym_section_ == NULL)
1730 dyn_global_index = 0;
1735 dyn_global_index = this->dynsym_section_->info();
1736 off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
1737 dynoff = this->dynsym_section_->offset() + locsize;
1738 dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
1739 gold_assert(static_cast<off_t>(dyncount * symsize)
1740 == this->dynsym_section_->data_size() - locsize);
1743 off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
1744 &this->sympool_, &local_symcount);
1746 if (!parameters->options().strip_all())
1748 this->sympool_.set_string_offsets();
1750 const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
1751 Output_section* osymtab = this->make_output_section(symtab_name,
1754 this->symtab_section_ = osymtab;
1756 Output_section_data* pos = new Output_data_fixed_space(off - startoff,
1758 osymtab->add_output_section_data(pos);
1760 const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
1761 Output_section* ostrtab = this->make_output_section(strtab_name,
1765 Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
1766 ostrtab->add_output_section_data(pstr);
1768 osymtab->set_file_offset(startoff);
1769 osymtab->finalize_data_size();
1770 osymtab->set_link_section(ostrtab);
1771 osymtab->set_info(local_symcount);
1772 osymtab->set_entsize(symsize);
1778 // Create the .shstrtab section, which holds the names of the
1779 // sections. At the time this is called, we have created all the
1780 // output sections except .shstrtab itself.
1783 Layout::create_shstrtab()
1785 // FIXME: We don't need to create a .shstrtab section if we are
1786 // stripping everything.
1788 const char* name = this->namepool_.add(".shstrtab", false, NULL);
1790 Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0);
1792 // We can't write out this section until we've set all the section
1793 // names, and we don't set the names of compressed output sections
1794 // until relocations are complete.
1795 os->set_after_input_sections();
1797 Output_section_data* posd = new Output_data_strtab(&this->namepool_);
1798 os->add_output_section_data(posd);
1803 // Create the section headers. SIZE is 32 or 64. OFF is the file
1807 Layout::create_shdrs(off_t* poff)
1809 Output_section_headers* oshdrs;
1810 oshdrs = new Output_section_headers(this,
1811 &this->segment_list_,
1812 &this->section_list_,
1813 &this->unattached_section_list_,
1815 off_t off = align_address(*poff, oshdrs->addralign());
1816 oshdrs->set_address_and_file_offset(0, off);
1817 off += oshdrs->data_size();
1819 this->section_headers_ = oshdrs;
1822 // Create the dynamic symbol table.
1825 Layout::create_dynamic_symtab(const Input_objects* input_objects,
1826 Symbol_table* symtab,
1827 Output_section **pdynstr,
1828 unsigned int* plocal_dynamic_count,
1829 std::vector<Symbol*>* pdynamic_symbols,
1830 Versions* pversions)
1832 // Count all the symbols in the dynamic symbol table, and set the
1833 // dynamic symbol indexes.
1835 // Skip symbol 0, which is always all zeroes.
1836 unsigned int index = 1;
1838 // Add STT_SECTION symbols for each Output section which needs one.
1839 for (Section_list::iterator p = this->section_list_.begin();
1840 p != this->section_list_.end();
1843 if (!(*p)->needs_dynsym_index())
1844 (*p)->set_dynsym_index(-1U);
1847 (*p)->set_dynsym_index(index);
1852 // Count the local symbols that need to go in the dynamic symbol table,
1853 // and set the dynamic symbol indexes.
1854 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1855 p != input_objects->relobj_end();
1858 unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
1862 unsigned int local_symcount = index;
1863 *plocal_dynamic_count = local_symcount;
1865 // FIXME: We have to tell set_dynsym_indexes whether the
1866 // -E/--export-dynamic option was used.
1867 index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
1868 &this->dynpool_, pversions);
1872 const int size = parameters->target().get_size();
1875 symsize = elfcpp::Elf_sizes<32>::sym_size;
1878 else if (size == 64)
1880 symsize = elfcpp::Elf_sizes<64>::sym_size;
1886 // Create the dynamic symbol table section.
1888 Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
1893 Output_section_data* odata = new Output_data_fixed_space(index * symsize,
1895 dynsym->add_output_section_data(odata);
1897 dynsym->set_info(local_symcount);
1898 dynsym->set_entsize(symsize);
1899 dynsym->set_addralign(align);
1901 this->dynsym_section_ = dynsym;
1903 Output_data_dynamic* const odyn = this->dynamic_data_;
1904 odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
1905 odyn->add_constant(elfcpp::DT_SYMENT, symsize);
1907 // Create the dynamic string table section.
1909 Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
1914 Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
1915 dynstr->add_output_section_data(strdata);
1917 dynsym->set_link_section(dynstr);
1918 this->dynamic_section_->set_link_section(dynstr);
1920 odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
1921 odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
1925 // Create the hash tables.
1927 // FIXME: We need an option to create a GNU hash table.
1929 unsigned char* phash;
1930 unsigned int hashlen;
1931 Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
1934 Output_section* hashsec = this->choose_output_section(NULL, ".hash",
1939 Output_section_data* hashdata = new Output_data_const_buffer(phash,
1942 hashsec->add_output_section_data(hashdata);
1944 hashsec->set_link_section(dynsym);
1945 hashsec->set_entsize(4);
1947 odyn->add_section_address(elfcpp::DT_HASH, hashsec);
1950 // Assign offsets to each local portion of the dynamic symbol table.
1953 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
1955 Output_section* dynsym = this->dynsym_section_;
1956 gold_assert(dynsym != NULL);
1958 off_t off = dynsym->offset();
1960 // Skip the dummy symbol at the start of the section.
1961 off += dynsym->entsize();
1963 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1964 p != input_objects->relobj_end();
1967 unsigned int count = (*p)->set_local_dynsym_offset(off);
1968 off += count * dynsym->entsize();
1972 // Create the version sections.
1975 Layout::create_version_sections(const Versions* versions,
1976 const Symbol_table* symtab,
1977 unsigned int local_symcount,
1978 const std::vector<Symbol*>& dynamic_symbols,
1979 const Output_section* dynstr)
1981 if (!versions->any_defs() && !versions->any_needs())
1984 switch (parameters->size_and_endianness())
1986 #ifdef HAVE_TARGET_32_LITTLE
1987 case Parameters::TARGET_32_LITTLE:
1988 this->sized_create_version_sections
1989 SELECT_SIZE_ENDIAN_NAME(32, false)(
1990 versions, symtab, local_symcount, dynamic_symbols, dynstr
1991 SELECT_SIZE_ENDIAN(32, false));
1994 #ifdef HAVE_TARGET_32_BIG
1995 case Parameters::TARGET_32_BIG:
1996 this->sized_create_version_sections
1997 SELECT_SIZE_ENDIAN_NAME(32, true)(
1998 versions, symtab, local_symcount, dynamic_symbols, dynstr
1999 SELECT_SIZE_ENDIAN(32, true));
2002 #ifdef HAVE_TARGET_64_LITTLE
2003 case Parameters::TARGET_64_LITTLE:
2004 this->sized_create_version_sections
2005 SELECT_SIZE_ENDIAN_NAME(64, false)(
2006 versions, symtab, local_symcount, dynamic_symbols, dynstr
2007 SELECT_SIZE_ENDIAN(64, false));
2010 #ifdef HAVE_TARGET_64_BIG
2011 case Parameters::TARGET_64_BIG:
2012 this->sized_create_version_sections
2013 SELECT_SIZE_ENDIAN_NAME(64, true)(
2014 versions, symtab, local_symcount, dynamic_symbols, dynstr
2015 SELECT_SIZE_ENDIAN(64, true));
2023 // Create the version sections, sized version.
2025 template<int size, bool big_endian>
2027 Layout::sized_create_version_sections(
2028 const Versions* versions,
2029 const Symbol_table* symtab,
2030 unsigned int local_symcount,
2031 const std::vector<Symbol*>& dynamic_symbols,
2032 const Output_section* dynstr
2035 Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
2036 elfcpp::SHT_GNU_versym,
2040 unsigned char* vbuf;
2042 versions->symbol_section_contents SELECT_SIZE_ENDIAN_NAME(size, big_endian)(
2043 symtab, &this->dynpool_, local_symcount, dynamic_symbols, &vbuf, &vsize
2044 SELECT_SIZE_ENDIAN(size, big_endian));
2046 Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2);
2048 vsec->add_output_section_data(vdata);
2049 vsec->set_entsize(2);
2050 vsec->set_link_section(this->dynsym_section_);
2052 Output_data_dynamic* const odyn = this->dynamic_data_;
2053 odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
2055 if (versions->any_defs())
2057 Output_section* vdsec;
2058 vdsec= this->choose_output_section(NULL, ".gnu.version_d",
2059 elfcpp::SHT_GNU_verdef,
2063 unsigned char* vdbuf;
2064 unsigned int vdsize;
2065 unsigned int vdentries;
2066 versions->def_section_contents SELECT_SIZE_ENDIAN_NAME(size, big_endian)(
2067 &this->dynpool_, &vdbuf, &vdsize, &vdentries
2068 SELECT_SIZE_ENDIAN(size, big_endian));
2070 Output_section_data* vddata = new Output_data_const_buffer(vdbuf,
2074 vdsec->add_output_section_data(vddata);
2075 vdsec->set_link_section(dynstr);
2076 vdsec->set_info(vdentries);
2078 odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
2079 odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
2082 if (versions->any_needs())
2084 Output_section* vnsec;
2085 vnsec = this->choose_output_section(NULL, ".gnu.version_r",
2086 elfcpp::SHT_GNU_verneed,
2090 unsigned char* vnbuf;
2091 unsigned int vnsize;
2092 unsigned int vnentries;
2093 versions->need_section_contents SELECT_SIZE_ENDIAN_NAME(size, big_endian)
2094 (&this->dynpool_, &vnbuf, &vnsize, &vnentries
2095 SELECT_SIZE_ENDIAN(size, big_endian));
2097 Output_section_data* vndata = new Output_data_const_buffer(vnbuf,
2101 vnsec->add_output_section_data(vndata);
2102 vnsec->set_link_section(dynstr);
2103 vnsec->set_info(vnentries);
2105 odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
2106 odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
2110 // Create the .interp section and PT_INTERP segment.
2113 Layout::create_interp(const Target* target)
2115 const char* interp = this->options_.dynamic_linker();
2118 interp = target->dynamic_linker();
2119 gold_assert(interp != NULL);
2122 size_t len = strlen(interp) + 1;
2124 Output_section_data* odata = new Output_data_const(interp, len, 1);
2126 Output_section* osec = this->choose_output_section(NULL, ".interp",
2127 elfcpp::SHT_PROGBITS,
2130 osec->add_output_section_data(odata);
2132 if (!this->script_options_->saw_phdrs_clause())
2134 Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP,
2136 oseg->add_initial_output_section(osec, elfcpp::PF_R);
2140 // Finish the .dynamic section and PT_DYNAMIC segment.
2143 Layout::finish_dynamic_section(const Input_objects* input_objects,
2144 const Symbol_table* symtab)
2146 if (!this->script_options_->saw_phdrs_clause())
2148 Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
2151 oseg->add_initial_output_section(this->dynamic_section_,
2152 elfcpp::PF_R | elfcpp::PF_W);
2155 Output_data_dynamic* const odyn = this->dynamic_data_;
2157 for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
2158 p != input_objects->dynobj_end();
2161 // FIXME: Handle --as-needed.
2162 odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
2165 if (parameters->options().shared())
2167 const char* soname = this->options_.soname();
2169 odyn->add_string(elfcpp::DT_SONAME, soname);
2172 // FIXME: Support --init and --fini.
2173 Symbol* sym = symtab->lookup("_init");
2174 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
2175 odyn->add_symbol(elfcpp::DT_INIT, sym);
2177 sym = symtab->lookup("_fini");
2178 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
2179 odyn->add_symbol(elfcpp::DT_FINI, sym);
2181 // FIXME: Support DT_INIT_ARRAY and DT_FINI_ARRAY.
2183 // Add a DT_RPATH entry if needed.
2184 const General_options::Dir_list& rpath(this->options_.rpath());
2187 std::string rpath_val;
2188 for (General_options::Dir_list::const_iterator p = rpath.begin();
2192 if (rpath_val.empty())
2193 rpath_val = p->name();
2196 // Eliminate duplicates.
2197 General_options::Dir_list::const_iterator q;
2198 for (q = rpath.begin(); q != p; ++q)
2199 if (q->name() == p->name())
2204 rpath_val += p->name();
2209 odyn->add_string(elfcpp::DT_RPATH, rpath_val);
2212 // Look for text segments that have dynamic relocations.
2213 bool have_textrel = false;
2214 if (!this->script_options_->saw_sections_clause())
2216 for (Segment_list::const_iterator p = this->segment_list_.begin();
2217 p != this->segment_list_.end();
2220 if (((*p)->flags() & elfcpp::PF_W) == 0
2221 && (*p)->dynamic_reloc_count() > 0)
2223 have_textrel = true;
2230 // We don't know the section -> segment mapping, so we are
2231 // conservative and just look for readonly sections with
2232 // relocations. If those sections wind up in writable segments,
2233 // then we have created an unnecessary DT_TEXTREL entry.
2234 for (Section_list::const_iterator p = this->section_list_.begin();
2235 p != this->section_list_.end();
2238 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
2239 && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
2240 && ((*p)->dynamic_reloc_count() > 0))
2242 have_textrel = true;
2248 // Add a DT_FLAGS entry. We add it even if no flags are set so that
2249 // post-link tools can easily modify these flags if desired.
2250 unsigned int flags = 0;
2253 // Add a DT_TEXTREL for compatibility with older loaders.
2254 odyn->add_constant(elfcpp::DT_TEXTREL, 0);
2255 flags |= elfcpp::DF_TEXTREL;
2257 if (parameters->options().shared() && this->has_static_tls())
2258 flags |= elfcpp::DF_STATIC_TLS;
2259 odyn->add_constant(elfcpp::DT_FLAGS, flags);
2262 // The mapping of .gnu.linkonce section names to real section names.
2264 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
2265 const Layout::Linkonce_mapping Layout::linkonce_mapping[] =
2267 MAPPING_INIT("d.rel.ro", ".data.rel.ro"), // Must be before "d".
2268 MAPPING_INIT("t", ".text"),
2269 MAPPING_INIT("r", ".rodata"),
2270 MAPPING_INIT("d", ".data"),
2271 MAPPING_INIT("b", ".bss"),
2272 MAPPING_INIT("s", ".sdata"),
2273 MAPPING_INIT("sb", ".sbss"),
2274 MAPPING_INIT("s2", ".sdata2"),
2275 MAPPING_INIT("sb2", ".sbss2"),
2276 MAPPING_INIT("wi", ".debug_info"),
2277 MAPPING_INIT("td", ".tdata"),
2278 MAPPING_INIT("tb", ".tbss"),
2279 MAPPING_INIT("lr", ".lrodata"),
2280 MAPPING_INIT("l", ".ldata"),
2281 MAPPING_INIT("lb", ".lbss"),
2285 const int Layout::linkonce_mapping_count =
2286 sizeof(Layout::linkonce_mapping) / sizeof(Layout::linkonce_mapping[0]);
2288 // Return the name of the output section to use for a .gnu.linkonce
2289 // section. This is based on the default ELF linker script of the old
2290 // GNU linker. For example, we map a name like ".gnu.linkonce.t.foo"
2291 // to ".text". Set *PLEN to the length of the name. *PLEN is
2292 // initialized to the length of NAME.
2295 Layout::linkonce_output_name(const char* name, size_t *plen)
2297 const char* s = name + sizeof(".gnu.linkonce") - 1;
2301 const Linkonce_mapping* plm = linkonce_mapping;
2302 for (int i = 0; i < linkonce_mapping_count; ++i, ++plm)
2304 if (strncmp(s, plm->from, plm->fromlen) == 0 && s[plm->fromlen] == '.')
2313 // Choose the output section name to use given an input section name.
2314 // Set *PLEN to the length of the name. *PLEN is initialized to the
2318 Layout::output_section_name(const char* name, size_t* plen)
2320 if (Layout::is_linkonce(name))
2322 // .gnu.linkonce sections are laid out as though they were named
2323 // for the sections are placed into.
2324 return Layout::linkonce_output_name(name, plen);
2327 // gcc 4.3 generates the following sorts of section names when it
2328 // needs a section name specific to a function:
2334 // .data.rel.local.FN
2336 // .data.rel.ro.local.FN
2343 // The GNU linker maps all of those to the part before the .FN,
2344 // except that .data.rel.local.FN is mapped to .data, and
2345 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
2346 // beginning with .data.rel.ro.local are grouped together.
2348 // For an anonymous namespace, the string FN can contain a '.'.
2350 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
2351 // GNU linker maps to .rodata.
2353 // The .data.rel.ro sections enable a security feature triggered by
2354 // the -z relro option. Section which need to be relocated at
2355 // program startup time but which may be readonly after startup are
2356 // grouped into .data.rel.ro. They are then put into a PT_GNU_RELRO
2357 // segment. The dynamic linker will make that segment writable,
2358 // perform relocations, and then make it read-only. FIXME: We do
2359 // not yet implement this optimization.
2361 // It is hard to handle this in a principled way.
2363 // These are the rules we follow:
2365 // If the section name has no initial '.', or no dot other than an
2366 // initial '.', we use the name unchanged (i.e., "mysection" and
2367 // ".text" are unchanged).
2369 // If the name starts with ".data.rel.ro" we use ".data.rel.ro".
2371 // Otherwise, we drop the second '.' and everything that comes after
2372 // it (i.e., ".text.XXX" becomes ".text").
2374 const char* s = name;
2378 const char* sdot = strchr(s, '.');
2382 const char* const data_rel_ro = ".data.rel.ro";
2383 if (strncmp(name, data_rel_ro, strlen(data_rel_ro)) == 0)
2385 *plen = strlen(data_rel_ro);
2389 *plen = sdot - name;
2393 // Record the signature of a comdat section, and return whether to
2394 // include it in the link. If GROUP is true, this is a regular
2395 // section group. If GROUP is false, this is a group signature
2396 // derived from the name of a linkonce section. We want linkonce
2397 // signatures and group signatures to block each other, but we don't
2398 // want a linkonce signature to block another linkonce signature.
2401 Layout::add_comdat(const char* signature, bool group)
2403 std::string sig(signature);
2404 std::pair<Signatures::iterator, bool> ins(
2405 this->signatures_.insert(std::make_pair(sig, group)));
2409 // This is the first time we've seen this signature.
2413 if (ins.first->second)
2415 // We've already seen a real section group with this signature.
2420 // This is a real section group, and we've already seen a
2421 // linkonce section with this signature. Record that we've seen
2422 // a section group, and don't include this section group.
2423 ins.first->second = true;
2428 // We've already seen a linkonce section and this is a linkonce
2429 // section. These don't block each other--this may be the same
2430 // symbol name with different section types.
2435 // Store the allocated sections into the section list.
2438 Layout::get_allocated_sections(Section_list* section_list) const
2440 for (Section_list::const_iterator p = this->section_list_.begin();
2441 p != this->section_list_.end();
2443 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
2444 section_list->push_back(*p);
2447 // Create an output segment.
2450 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
2452 gold_assert(!parameters->options().relocatable());
2453 Output_segment* oseg = new Output_segment(type, flags);
2454 this->segment_list_.push_back(oseg);
2458 // Write out the Output_sections. Most won't have anything to write,
2459 // since most of the data will come from input sections which are
2460 // handled elsewhere. But some Output_sections do have Output_data.
2463 Layout::write_output_sections(Output_file* of) const
2465 for (Section_list::const_iterator p = this->section_list_.begin();
2466 p != this->section_list_.end();
2469 if (!(*p)->after_input_sections())
2474 // Write out data not associated with a section or the symbol table.
2477 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
2479 if (!parameters->options().strip_all())
2481 const Output_section* symtab_section = this->symtab_section_;
2482 for (Section_list::const_iterator p = this->section_list_.begin();
2483 p != this->section_list_.end();
2486 if ((*p)->needs_symtab_index())
2488 gold_assert(symtab_section != NULL);
2489 unsigned int index = (*p)->symtab_index();
2490 gold_assert(index > 0 && index != -1U);
2491 off_t off = (symtab_section->offset()
2492 + index * symtab_section->entsize());
2493 symtab->write_section_symbol(*p, of, off);
2498 const Output_section* dynsym_section = this->dynsym_section_;
2499 for (Section_list::const_iterator p = this->section_list_.begin();
2500 p != this->section_list_.end();
2503 if ((*p)->needs_dynsym_index())
2505 gold_assert(dynsym_section != NULL);
2506 unsigned int index = (*p)->dynsym_index();
2507 gold_assert(index > 0 && index != -1U);
2508 off_t off = (dynsym_section->offset()
2509 + index * dynsym_section->entsize());
2510 symtab->write_section_symbol(*p, of, off);
2514 // Write out the Output_data which are not in an Output_section.
2515 for (Data_list::const_iterator p = this->special_output_list_.begin();
2516 p != this->special_output_list_.end();
2521 // Write out the Output_sections which can only be written after the
2522 // input sections are complete.
2525 Layout::write_sections_after_input_sections(Output_file* of)
2527 // Determine the final section offsets, and thus the final output
2528 // file size. Note we finalize the .shstrab last, to allow the
2529 // after_input_section sections to modify their section-names before
2531 if (this->any_postprocessing_sections_)
2533 off_t off = this->output_file_size_;
2534 off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
2536 // Now that we've finalized the names, we can finalize the shstrab.
2538 this->set_section_offsets(off,
2539 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
2541 if (off > this->output_file_size_)
2544 this->output_file_size_ = off;
2548 for (Section_list::const_iterator p = this->section_list_.begin();
2549 p != this->section_list_.end();
2552 if ((*p)->after_input_sections())
2556 this->section_headers_->write(of);
2559 // Write out a binary file. This is called after the link is
2560 // complete. IN is the temporary output file we used to generate the
2561 // ELF code. We simply walk through the segments, read them from
2562 // their file offset in IN, and write them to their load address in
2563 // the output file. FIXME: with a bit more work, we could support
2564 // S-records and/or Intel hex format here.
2567 Layout::write_binary(Output_file* in) const
2569 gold_assert(this->options_.oformat()
2570 == General_options::OBJECT_FORMAT_BINARY);
2572 // Get the size of the binary file.
2573 uint64_t max_load_address = 0;
2574 for (Segment_list::const_iterator p = this->segment_list_.begin();
2575 p != this->segment_list_.end();
2578 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
2580 uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
2581 if (max_paddr > max_load_address)
2582 max_load_address = max_paddr;
2586 Output_file out(parameters->options().output_file_name());
2587 out.open(max_load_address);
2589 for (Segment_list::const_iterator p = this->segment_list_.begin();
2590 p != this->segment_list_.end();
2593 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
2595 const unsigned char* vin = in->get_input_view((*p)->offset(),
2597 unsigned char* vout = out.get_output_view((*p)->paddr(),
2599 memcpy(vout, vin, (*p)->filesz());
2600 out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
2601 in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
2608 // Print statistical information to stderr. This is used for --stats.
2611 Layout::print_stats() const
2613 this->namepool_.print_stats("section name pool");
2614 this->sympool_.print_stats("output symbol name pool");
2615 this->dynpool_.print_stats("dynamic name pool");
2617 for (Section_list::const_iterator p = this->section_list_.begin();
2618 p != this->section_list_.end();
2620 (*p)->print_merge_stats();
2623 // Write_sections_task methods.
2625 // We can always run this task.
2628 Write_sections_task::is_runnable()
2633 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
2637 Write_sections_task::locks(Task_locker* tl)
2639 tl->add(this, this->output_sections_blocker_);
2640 tl->add(this, this->final_blocker_);
2643 // Run the task--write out the data.
2646 Write_sections_task::run(Workqueue*)
2648 this->layout_->write_output_sections(this->of_);
2651 // Write_data_task methods.
2653 // We can always run this task.
2656 Write_data_task::is_runnable()
2661 // We need to unlock FINAL_BLOCKER when finished.
2664 Write_data_task::locks(Task_locker* tl)
2666 tl->add(this, this->final_blocker_);
2669 // Run the task--write out the data.
2672 Write_data_task::run(Workqueue*)
2674 this->layout_->write_data(this->symtab_, this->of_);
2677 // Write_symbols_task methods.
2679 // We can always run this task.
2682 Write_symbols_task::is_runnable()
2687 // We need to unlock FINAL_BLOCKER when finished.
2690 Write_symbols_task::locks(Task_locker* tl)
2692 tl->add(this, this->final_blocker_);
2695 // Run the task--write out the symbols.
2698 Write_symbols_task::run(Workqueue*)
2700 this->symtab_->write_globals(this->input_objects_, this->sympool_,
2701 this->dynpool_, this->of_);
2704 // Write_after_input_sections_task methods.
2706 // We can only run this task after the input sections have completed.
2709 Write_after_input_sections_task::is_runnable()
2711 if (this->input_sections_blocker_->is_blocked())
2712 return this->input_sections_blocker_;
2716 // We need to unlock FINAL_BLOCKER when finished.
2719 Write_after_input_sections_task::locks(Task_locker* tl)
2721 tl->add(this, this->final_blocker_);
2727 Write_after_input_sections_task::run(Workqueue*)
2729 this->layout_->write_sections_after_input_sections(this->of_);
2732 // Close_task_runner methods.
2734 // Run the task--close the file.
2737 Close_task_runner::run(Workqueue*, const Task*)
2739 // If we've been asked to create a binary file, we do so here.
2740 if (this->options_->oformat() != General_options::OBJECT_FORMAT_ELF)
2741 this->layout_->write_binary(this->of_);
2746 // Instantiate the templates we need. We could use the configure
2747 // script to restrict this to only the ones for implemented targets.
2749 #ifdef HAVE_TARGET_32_LITTLE
2752 Layout::layout<32, false>(Sized_relobj<32, false>* object, unsigned int shndx,
2754 const elfcpp::Shdr<32, false>& shdr,
2755 unsigned int, unsigned int, off_t*);
2758 #ifdef HAVE_TARGET_32_BIG
2761 Layout::layout<32, true>(Sized_relobj<32, true>* object, unsigned int shndx,
2763 const elfcpp::Shdr<32, true>& shdr,
2764 unsigned int, unsigned int, off_t*);
2767 #ifdef HAVE_TARGET_64_LITTLE
2770 Layout::layout<64, false>(Sized_relobj<64, false>* object, unsigned int shndx,
2772 const elfcpp::Shdr<64, false>& shdr,
2773 unsigned int, unsigned int, off_t*);
2776 #ifdef HAVE_TARGET_64_BIG
2779 Layout::layout<64, true>(Sized_relobj<64, true>* object, unsigned int shndx,
2781 const elfcpp::Shdr<64, true>& shdr,
2782 unsigned int, unsigned int, off_t*);
2785 #ifdef HAVE_TARGET_32_LITTLE
2788 Layout::layout_reloc<32, false>(Sized_relobj<32, false>* object,
2789 unsigned int reloc_shndx,
2790 const elfcpp::Shdr<32, false>& shdr,
2791 Output_section* data_section,
2792 Relocatable_relocs* rr);
2795 #ifdef HAVE_TARGET_32_BIG
2798 Layout::layout_reloc<32, true>(Sized_relobj<32, true>* object,
2799 unsigned int reloc_shndx,
2800 const elfcpp::Shdr<32, true>& shdr,
2801 Output_section* data_section,
2802 Relocatable_relocs* rr);
2805 #ifdef HAVE_TARGET_64_LITTLE
2808 Layout::layout_reloc<64, false>(Sized_relobj<64, false>* object,
2809 unsigned int reloc_shndx,
2810 const elfcpp::Shdr<64, false>& shdr,
2811 Output_section* data_section,
2812 Relocatable_relocs* rr);
2815 #ifdef HAVE_TARGET_64_BIG
2818 Layout::layout_reloc<64, true>(Sized_relobj<64, true>* object,
2819 unsigned int reloc_shndx,
2820 const elfcpp::Shdr<64, true>& shdr,
2821 Output_section* data_section,
2822 Relocatable_relocs* rr);
2825 #ifdef HAVE_TARGET_32_LITTLE
2828 Layout::layout_group<32, false>(Symbol_table* symtab,
2829 Sized_relobj<32, false>* object,
2831 const char* group_section_name,
2832 const char* signature,
2833 const elfcpp::Shdr<32, false>& shdr,
2834 const elfcpp::Elf_Word* contents);
2837 #ifdef HAVE_TARGET_32_BIG
2840 Layout::layout_group<32, true>(Symbol_table* symtab,
2841 Sized_relobj<32, true>* object,
2843 const char* group_section_name,
2844 const char* signature,
2845 const elfcpp::Shdr<32, true>& shdr,
2846 const elfcpp::Elf_Word* contents);
2849 #ifdef HAVE_TARGET_64_LITTLE
2852 Layout::layout_group<64, false>(Symbol_table* symtab,
2853 Sized_relobj<64, false>* object,
2855 const char* group_section_name,
2856 const char* signature,
2857 const elfcpp::Shdr<64, false>& shdr,
2858 const elfcpp::Elf_Word* contents);
2861 #ifdef HAVE_TARGET_64_BIG
2864 Layout::layout_group<64, true>(Symbol_table* symtab,
2865 Sized_relobj<64, true>* object,
2867 const char* group_section_name,
2868 const char* signature,
2869 const elfcpp::Shdr<64, true>& shdr,
2870 const elfcpp::Elf_Word* contents);
2873 #ifdef HAVE_TARGET_32_LITTLE
2876 Layout::layout_eh_frame<32, false>(Sized_relobj<32, false>* object,
2877 const unsigned char* symbols,
2879 const unsigned char* symbol_names,
2880 off_t symbol_names_size,
2882 const elfcpp::Shdr<32, false>& shdr,
2883 unsigned int reloc_shndx,
2884 unsigned int reloc_type,
2888 #ifdef HAVE_TARGET_32_BIG
2891 Layout::layout_eh_frame<32, true>(Sized_relobj<32, true>* object,
2892 const unsigned char* symbols,
2894 const unsigned char* symbol_names,
2895 off_t symbol_names_size,
2897 const elfcpp::Shdr<32, true>& shdr,
2898 unsigned int reloc_shndx,
2899 unsigned int reloc_type,
2903 #ifdef HAVE_TARGET_64_LITTLE
2906 Layout::layout_eh_frame<64, false>(Sized_relobj<64, false>* object,
2907 const unsigned char* symbols,
2909 const unsigned char* symbol_names,
2910 off_t symbol_names_size,
2912 const elfcpp::Shdr<64, false>& shdr,
2913 unsigned int reloc_shndx,
2914 unsigned int reloc_type,
2918 #ifdef HAVE_TARGET_64_BIG
2921 Layout::layout_eh_frame<64, true>(Sized_relobj<64, true>* object,
2922 const unsigned char* symbols,
2924 const unsigned char* symbol_names,
2925 off_t symbol_names_size,
2927 const elfcpp::Shdr<64, true>& shdr,
2928 unsigned int reloc_shndx,
2929 unsigned int reloc_type,
2933 } // End namespace gold.