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 // Return the number of segments we expect to see.
718 Layout::expected_segment_count() const
720 size_t ret = this->segment_list_.size();
722 // If we didn't see a SECTIONS clause in a linker script, we should
723 // already have the complete list of segments. Otherwise we ask the
724 // SECTIONS clause how many segments it expects, and add in the ones
725 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
727 if (!this->script_options_->saw_sections_clause())
731 const Script_sections* ss = this->script_options_->script_sections();
732 return ret + ss->expected_segment_count(this);
736 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
737 // is whether we saw a .note.GNU-stack section in the object file.
738 // GNU_STACK_FLAGS is the section flags. The flags give the
739 // protection required for stack memory. We record this in an
740 // executable as a PT_GNU_STACK segment. If an object file does not
741 // have a .note.GNU-stack segment, we must assume that it is an old
742 // object. On some targets that will force an executable stack.
745 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags)
748 this->input_without_gnu_stack_note_ = true;
751 this->input_with_gnu_stack_note_ = true;
752 if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
753 this->input_requires_executable_stack_ = true;
757 // Create the dynamic sections which are needed before we read the
761 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
763 if (parameters->doing_static_link())
766 this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
769 | elfcpp::SHF_WRITE),
772 symtab->define_in_output_data("_DYNAMIC", NULL, this->dynamic_section_, 0, 0,
773 elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
774 elfcpp::STV_HIDDEN, 0, false, false);
776 this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_);
778 this->dynamic_section_->add_output_section_data(this->dynamic_data_);
781 // For each output section whose name can be represented as C symbol,
782 // define __start and __stop symbols for the section. This is a GNU
786 Layout::define_section_symbols(Symbol_table* symtab)
788 for (Section_list::const_iterator p = this->section_list_.begin();
789 p != this->section_list_.end();
792 const char* const name = (*p)->name();
793 if (name[strspn(name,
795 "ABCDEFGHIJKLMNOPWRSTUVWXYZ"
796 "abcdefghijklmnopqrstuvwxyz"
800 const std::string name_string(name);
801 const std::string start_name("__start_" + name_string);
802 const std::string stop_name("__stop_" + name_string);
804 symtab->define_in_output_data(start_name.c_str(),
813 false, // offset_is_from_end
814 true); // only_if_ref
816 symtab->define_in_output_data(stop_name.c_str(),
825 true, // offset_is_from_end
826 true); // only_if_ref
831 // Define symbols for group signatures.
834 Layout::define_group_signatures(Symbol_table* symtab)
836 for (Group_signatures::iterator p = this->group_signatures_.begin();
837 p != this->group_signatures_.end();
840 Symbol* sym = symtab->lookup(p->signature, NULL);
842 p->section->set_info_symndx(sym);
845 // Force the name of the group section to the group
846 // signature, and use the group's section symbol as the
848 if (strcmp(p->section->name(), p->signature) != 0)
850 const char* name = this->namepool_.add(p->signature,
852 p->section->set_name(name);
854 p->section->set_needs_symtab_index();
855 p->section->set_info_section_symndx(p->section);
859 this->group_signatures_.clear();
862 // Find the first read-only PT_LOAD segment, creating one if
866 Layout::find_first_load_seg()
868 for (Segment_list::const_iterator p = this->segment_list_.begin();
869 p != this->segment_list_.end();
872 if ((*p)->type() == elfcpp::PT_LOAD
873 && ((*p)->flags() & elfcpp::PF_R) != 0
874 && ((*p)->flags() & elfcpp::PF_W) == 0)
878 gold_assert(!this->script_options_->saw_phdrs_clause());
880 Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
885 // Finalize the layout. When this is called, we have created all the
886 // output sections and all the output segments which are based on
887 // input sections. We have several things to do, and we have to do
888 // them in the right order, so that we get the right results correctly
891 // 1) Finalize the list of output segments and create the segment
894 // 2) Finalize the dynamic symbol table and associated sections.
896 // 3) Determine the final file offset of all the output segments.
898 // 4) Determine the final file offset of all the SHF_ALLOC output
901 // 5) Create the symbol table sections and the section name table
904 // 6) Finalize the symbol table: set symbol values to their final
905 // value and make a final determination of which symbols are going
906 // into the output symbol table.
908 // 7) Create the section table header.
910 // 8) Determine the final file offset of all the output sections which
911 // are not SHF_ALLOC, including the section table header.
913 // 9) Finalize the ELF file header.
915 // This function returns the size of the output file.
918 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
919 Target* target, const Task* task)
921 target->finalize_sections(this);
923 this->count_local_symbols(task, input_objects);
925 this->create_gold_note();
926 this->create_executable_stack_info(target);
928 Output_segment* phdr_seg = NULL;
929 if (!parameters->options().relocatable() && !parameters->doing_static_link())
931 // There was a dynamic object in the link. We need to create
932 // some information for the dynamic linker.
934 // Create the PT_PHDR segment which will hold the program
936 if (!this->script_options_->saw_phdrs_clause())
937 phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
939 // Create the dynamic symbol table, including the hash table.
940 Output_section* dynstr;
941 std::vector<Symbol*> dynamic_symbols;
942 unsigned int local_dynamic_count;
943 Versions versions(*this->script_options()->version_script_info(),
945 this->create_dynamic_symtab(input_objects, symtab, &dynstr,
946 &local_dynamic_count, &dynamic_symbols,
949 // Create the .interp section to hold the name of the
950 // interpreter, and put it in a PT_INTERP segment.
951 if (!parameters->options().shared())
952 this->create_interp(target);
954 // Finish the .dynamic section to hold the dynamic data, and put
955 // it in a PT_DYNAMIC segment.
956 this->finish_dynamic_section(input_objects, symtab);
958 // We should have added everything we need to the dynamic string
960 this->dynpool_.set_string_offsets();
962 // Create the version sections. We can't do this until the
963 // dynamic string table is complete.
964 this->create_version_sections(&versions, symtab, local_dynamic_count,
965 dynamic_symbols, dynstr);
968 // If there is a SECTIONS clause, put all the input sections into
969 // the required order.
970 Output_segment* load_seg;
971 if (this->script_options_->saw_sections_clause())
972 load_seg = this->set_section_addresses_from_script(symtab);
973 else if (parameters->options().relocatable())
976 load_seg = this->find_first_load_seg();
978 if (this->options_.oformat() != General_options::OBJECT_FORMAT_ELF)
981 gold_assert(phdr_seg == NULL || load_seg != NULL);
983 // Lay out the segment headers.
984 Output_segment_headers* segment_headers;
985 if (parameters->options().relocatable())
986 segment_headers = NULL;
989 segment_headers = new Output_segment_headers(this->segment_list_);
990 if (load_seg != NULL)
991 load_seg->add_initial_output_data(segment_headers);
992 if (phdr_seg != NULL)
993 phdr_seg->add_initial_output_data(segment_headers);
996 // Lay out the file header.
997 Output_file_header* file_header;
998 file_header = new Output_file_header(target, symtab, segment_headers,
999 this->options_.entry());
1000 if (load_seg != NULL)
1001 load_seg->add_initial_output_data(file_header);
1003 this->special_output_list_.push_back(file_header);
1004 if (segment_headers != NULL)
1005 this->special_output_list_.push_back(segment_headers);
1007 if (this->script_options_->saw_phdrs_clause()
1008 && !parameters->options().relocatable())
1010 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
1011 // clause in a linker script.
1012 Script_sections* ss = this->script_options_->script_sections();
1013 ss->put_headers_in_phdrs(file_header, segment_headers);
1016 // We set the output section indexes in set_segment_offsets and
1017 // set_section_indexes.
1018 unsigned int shndx = 1;
1020 // Set the file offsets of all the segments, and all the sections
1023 if (!parameters->options().relocatable())
1024 off = this->set_segment_offsets(target, load_seg, &shndx);
1026 off = this->set_relocatable_section_offsets(file_header, &shndx);
1028 // Set the file offsets of all the non-data sections we've seen so
1029 // far which don't have to wait for the input sections. We need
1030 // this in order to finalize local symbols in non-allocated
1032 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1034 // Create the symbol table sections.
1035 this->create_symtab_sections(input_objects, symtab, &off);
1036 if (!parameters->doing_static_link())
1037 this->assign_local_dynsym_offsets(input_objects);
1039 // Process any symbol assignments from a linker script. This must
1040 // be called after the symbol table has been finalized.
1041 this->script_options_->finalize_symbols(symtab, this);
1043 // Create the .shstrtab section.
1044 Output_section* shstrtab_section = this->create_shstrtab();
1046 // Set the file offsets of the rest of the non-data sections which
1047 // don't have to wait for the input sections.
1048 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1050 // Now that all sections have been created, set the section indexes.
1051 shndx = this->set_section_indexes(shndx);
1053 // Create the section table header.
1054 this->create_shdrs(&off);
1056 // If there are no sections which require postprocessing, we can
1057 // handle the section names now, and avoid a resize later.
1058 if (!this->any_postprocessing_sections_)
1059 off = this->set_section_offsets(off,
1060 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
1062 file_header->set_section_info(this->section_headers_, shstrtab_section);
1064 // Now we know exactly where everything goes in the output file
1065 // (except for non-allocated sections which require postprocessing).
1066 Output_data::layout_complete();
1068 this->output_file_size_ = off;
1073 // Create a .note section for an executable or shared library. This
1074 // records the version of gold used to create the binary.
1077 Layout::create_gold_note()
1079 if (parameters->options().relocatable())
1082 // Authorities all agree that the values in a .note field should
1083 // be aligned on 4-byte boundaries for 32-bit binaries. However,
1084 // they differ on what the alignment is for 64-bit binaries.
1085 // The GABI says unambiguously they take 8-byte alignment:
1086 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
1087 // Other documentation says alignment should always be 4 bytes:
1088 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
1089 // GNU ld and GNU readelf both support the latter (at least as of
1090 // version 2.16.91), and glibc always generates the latter for
1091 // .note.ABI-tag (as of version 1.6), so that's the one we go with
1093 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
1094 const int size = parameters->target().get_size();
1096 const int size = 32;
1099 // The contents of the .note section.
1100 const char* name = "GNU";
1101 std::string desc(std::string("gold ") + gold::get_version_string());
1102 size_t namesz = strlen(name) + 1;
1103 size_t aligned_namesz = align_address(namesz, size / 8);
1104 size_t descsz = desc.length() + 1;
1105 size_t aligned_descsz = align_address(descsz, size / 8);
1106 const int note_type = 4;
1108 size_t notesz = 3 * (size / 8) + aligned_namesz + aligned_descsz;
1110 unsigned char buffer[128];
1111 gold_assert(sizeof buffer >= notesz);
1112 memset(buffer, 0, notesz);
1114 bool is_big_endian = parameters->target().is_big_endian();
1120 elfcpp::Swap<32, false>::writeval(buffer, namesz);
1121 elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
1122 elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
1126 elfcpp::Swap<32, true>::writeval(buffer, namesz);
1127 elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
1128 elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
1131 else if (size == 64)
1135 elfcpp::Swap<64, false>::writeval(buffer, namesz);
1136 elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
1137 elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
1141 elfcpp::Swap<64, true>::writeval(buffer, namesz);
1142 elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
1143 elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
1149 memcpy(buffer + 3 * (size / 8), name, namesz);
1150 memcpy(buffer + 3 * (size / 8) + aligned_namesz, desc.data(), descsz);
1152 const char* note_name = this->namepool_.add(".note", false, NULL);
1153 Output_section* os = this->make_output_section(note_name,
1156 Output_section_data* posd = new Output_data_const(buffer, notesz,
1158 os->add_output_section_data(posd);
1161 // Record whether the stack should be executable. This can be set
1162 // from the command line using the -z execstack or -z noexecstack
1163 // options. Otherwise, if any input file has a .note.GNU-stack
1164 // section with the SHF_EXECINSTR flag set, the stack should be
1165 // executable. Otherwise, if at least one input file a
1166 // .note.GNU-stack section, and some input file has no .note.GNU-stack
1167 // section, we use the target default for whether the stack should be
1168 // executable. Otherwise, we don't generate a stack note. When
1169 // generating a object file, we create a .note.GNU-stack section with
1170 // the appropriate marking. When generating an executable or shared
1171 // library, we create a PT_GNU_STACK segment.
1174 Layout::create_executable_stack_info(const Target* target)
1176 bool is_stack_executable;
1177 if (this->options_.is_execstack_set())
1178 is_stack_executable = this->options_.is_stack_executable();
1179 else if (!this->input_with_gnu_stack_note_)
1183 if (this->input_requires_executable_stack_)
1184 is_stack_executable = true;
1185 else if (this->input_without_gnu_stack_note_)
1186 is_stack_executable = target->is_default_stack_executable();
1188 is_stack_executable = false;
1191 if (parameters->options().relocatable())
1193 const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
1194 elfcpp::Elf_Xword flags = 0;
1195 if (is_stack_executable)
1196 flags |= elfcpp::SHF_EXECINSTR;
1197 this->make_output_section(name, elfcpp::SHT_PROGBITS, flags);
1201 if (this->script_options_->saw_phdrs_clause())
1203 int flags = elfcpp::PF_R | elfcpp::PF_W;
1204 if (is_stack_executable)
1205 flags |= elfcpp::PF_X;
1206 this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
1210 // Return whether SEG1 should be before SEG2 in the output file. This
1211 // is based entirely on the segment type and flags. When this is
1212 // called the segment addresses has normally not yet been set.
1215 Layout::segment_precedes(const Output_segment* seg1,
1216 const Output_segment* seg2)
1218 elfcpp::Elf_Word type1 = seg1->type();
1219 elfcpp::Elf_Word type2 = seg2->type();
1221 // The single PT_PHDR segment is required to precede any loadable
1222 // segment. We simply make it always first.
1223 if (type1 == elfcpp::PT_PHDR)
1225 gold_assert(type2 != elfcpp::PT_PHDR);
1228 if (type2 == elfcpp::PT_PHDR)
1231 // The single PT_INTERP segment is required to precede any loadable
1232 // segment. We simply make it always second.
1233 if (type1 == elfcpp::PT_INTERP)
1235 gold_assert(type2 != elfcpp::PT_INTERP);
1238 if (type2 == elfcpp::PT_INTERP)
1241 // We then put PT_LOAD segments before any other segments.
1242 if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
1244 if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
1247 // We put the PT_TLS segment last, because that is where the dynamic
1248 // linker expects to find it (this is just for efficiency; other
1249 // positions would also work correctly).
1250 if (type1 == elfcpp::PT_TLS && type2 != elfcpp::PT_TLS)
1252 if (type2 == elfcpp::PT_TLS && type1 != elfcpp::PT_TLS)
1255 const elfcpp::Elf_Word flags1 = seg1->flags();
1256 const elfcpp::Elf_Word flags2 = seg2->flags();
1258 // The order of non-PT_LOAD segments is unimportant. We simply sort
1259 // by the numeric segment type and flags values. There should not
1260 // be more than one segment with the same type and flags.
1261 if (type1 != elfcpp::PT_LOAD)
1264 return type1 < type2;
1265 gold_assert(flags1 != flags2);
1266 return flags1 < flags2;
1269 // If the addresses are set already, sort by load address.
1270 if (seg1->are_addresses_set())
1272 if (!seg2->are_addresses_set())
1275 unsigned int section_count1 = seg1->output_section_count();
1276 unsigned int section_count2 = seg2->output_section_count();
1277 if (section_count1 == 0 && section_count2 > 0)
1279 if (section_count1 > 0 && section_count2 == 0)
1282 uint64_t paddr1 = seg1->first_section_load_address();
1283 uint64_t paddr2 = seg2->first_section_load_address();
1284 if (paddr1 != paddr2)
1285 return paddr1 < paddr2;
1287 else if (seg2->are_addresses_set())
1290 // We sort PT_LOAD segments based on the flags. Readonly segments
1291 // come before writable segments. Then writable segments with data
1292 // come before writable segments without data. Then executable
1293 // segments come before non-executable segments. Then the unlikely
1294 // case of a non-readable segment comes before the normal case of a
1295 // readable segment. If there are multiple segments with the same
1296 // type and flags, we require that the address be set, and we sort
1297 // by virtual address and then physical address.
1298 if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
1299 return (flags1 & elfcpp::PF_W) == 0;
1300 if ((flags1 & elfcpp::PF_W) != 0
1301 && seg1->has_any_data_sections() != seg2->has_any_data_sections())
1302 return seg1->has_any_data_sections();
1303 if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
1304 return (flags1 & elfcpp::PF_X) != 0;
1305 if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
1306 return (flags1 & elfcpp::PF_R) == 0;
1308 // We shouldn't get here--we shouldn't create segments which we
1309 // can't distinguish.
1313 // Set the file offsets of all the segments, and all the sections they
1314 // contain. They have all been created. LOAD_SEG must be be laid out
1315 // first. Return the offset of the data to follow.
1318 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
1319 unsigned int *pshndx)
1321 // Sort them into the final order.
1322 std::sort(this->segment_list_.begin(), this->segment_list_.end(),
1323 Layout::Compare_segments());
1325 // Find the PT_LOAD segments, and set their addresses and offsets
1326 // and their section's addresses and offsets.
1328 if (this->options_.user_set_Ttext())
1329 addr = this->options_.Ttext();
1330 else if (parameters->options().shared())
1333 addr = target->default_text_segment_address();
1336 // If LOAD_SEG is NULL, then the file header and segment headers
1337 // will not be loadable. But they still need to be at offset 0 in
1338 // the file. Set their offsets now.
1339 if (load_seg == NULL)
1341 for (Data_list::iterator p = this->special_output_list_.begin();
1342 p != this->special_output_list_.end();
1345 off = align_address(off, (*p)->addralign());
1346 (*p)->set_address_and_file_offset(0, off);
1347 off += (*p)->data_size();
1351 bool was_readonly = false;
1352 for (Segment_list::iterator p = this->segment_list_.begin();
1353 p != this->segment_list_.end();
1356 if ((*p)->type() == elfcpp::PT_LOAD)
1358 if (load_seg != NULL && load_seg != *p)
1362 bool are_addresses_set = (*p)->are_addresses_set();
1363 if (are_addresses_set)
1365 // When it comes to setting file offsets, we care about
1366 // the physical address.
1367 addr = (*p)->paddr();
1369 else if (this->options_.user_set_Tdata()
1370 && ((*p)->flags() & elfcpp::PF_W) != 0
1371 && (!this->options_.user_set_Tbss()
1372 || (*p)->has_any_data_sections()))
1374 addr = this->options_.Tdata();
1375 are_addresses_set = true;
1377 else if (this->options_.user_set_Tbss()
1378 && ((*p)->flags() & elfcpp::PF_W) != 0
1379 && !(*p)->has_any_data_sections())
1381 addr = this->options_.Tbss();
1382 are_addresses_set = true;
1385 uint64_t orig_addr = addr;
1386 uint64_t orig_off = off;
1388 uint64_t aligned_addr = 0;
1389 uint64_t abi_pagesize = target->abi_pagesize();
1391 // FIXME: This should depend on the -n and -N options.
1392 (*p)->set_minimum_p_align(target->common_pagesize());
1394 if (are_addresses_set)
1396 // Adjust the file offset to the same address modulo the
1398 uint64_t unsigned_off = off;
1399 uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
1400 | (addr & (abi_pagesize - 1)));
1401 if (aligned_off < unsigned_off)
1402 aligned_off += abi_pagesize;
1407 // If the last segment was readonly, and this one is
1408 // not, then skip the address forward one page,
1409 // maintaining the same position within the page. This
1410 // lets us store both segments overlapping on a single
1411 // page in the file, but the loader will put them on
1412 // different pages in memory.
1414 addr = align_address(addr, (*p)->maximum_alignment());
1415 aligned_addr = addr;
1417 if (was_readonly && ((*p)->flags() & elfcpp::PF_W) != 0)
1419 if ((addr & (abi_pagesize - 1)) != 0)
1420 addr = addr + abi_pagesize;
1423 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
1426 unsigned int shndx_hold = *pshndx;
1427 uint64_t new_addr = (*p)->set_section_addresses(false, addr, &off,
1430 // Now that we know the size of this segment, we may be able
1431 // to save a page in memory, at the cost of wasting some
1432 // file space, by instead aligning to the start of a new
1433 // page. Here we use the real machine page size rather than
1434 // the ABI mandated page size.
1436 if (!are_addresses_set && aligned_addr != addr)
1438 uint64_t common_pagesize = target->common_pagesize();
1439 uint64_t first_off = (common_pagesize
1441 & (common_pagesize - 1)));
1442 uint64_t last_off = new_addr & (common_pagesize - 1);
1445 && ((aligned_addr & ~ (common_pagesize - 1))
1446 != (new_addr & ~ (common_pagesize - 1)))
1447 && first_off + last_off <= common_pagesize)
1449 *pshndx = shndx_hold;
1450 addr = align_address(aligned_addr, common_pagesize);
1451 addr = align_address(addr, (*p)->maximum_alignment());
1452 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
1453 new_addr = (*p)->set_section_addresses(true, addr, &off,
1460 if (((*p)->flags() & elfcpp::PF_W) == 0)
1461 was_readonly = true;
1465 // Handle the non-PT_LOAD segments, setting their offsets from their
1466 // section's offsets.
1467 for (Segment_list::iterator p = this->segment_list_.begin();
1468 p != this->segment_list_.end();
1471 if ((*p)->type() != elfcpp::PT_LOAD)
1475 // Set the TLS offsets for each section in the PT_TLS segment.
1476 if (this->tls_segment_ != NULL)
1477 this->tls_segment_->set_tls_offsets();
1482 // Set the offsets of all the allocated sections when doing a
1483 // relocatable link. This does the same jobs as set_segment_offsets,
1484 // only for a relocatable link.
1487 Layout::set_relocatable_section_offsets(Output_data* file_header,
1488 unsigned int *pshndx)
1492 file_header->set_address_and_file_offset(0, 0);
1493 off += file_header->data_size();
1495 for (Section_list::iterator p = this->section_list_.begin();
1496 p != this->section_list_.end();
1499 // We skip unallocated sections here, except that group sections
1500 // have to come first.
1501 if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
1502 && (*p)->type() != elfcpp::SHT_GROUP)
1505 off = align_address(off, (*p)->addralign());
1507 // The linker script might have set the address.
1508 if (!(*p)->is_address_valid())
1509 (*p)->set_address(0);
1510 (*p)->set_file_offset(off);
1511 (*p)->finalize_data_size();
1512 off += (*p)->data_size();
1514 (*p)->set_out_shndx(*pshndx);
1521 // Set the file offset of all the sections not associated with a
1525 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
1527 for (Section_list::iterator p = this->unattached_section_list_.begin();
1528 p != this->unattached_section_list_.end();
1531 // The symtab section is handled in create_symtab_sections.
1532 if (*p == this->symtab_section_)
1535 // If we've already set the data size, don't set it again.
1536 if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
1539 if (pass == BEFORE_INPUT_SECTIONS_PASS
1540 && (*p)->requires_postprocessing())
1542 (*p)->create_postprocessing_buffer();
1543 this->any_postprocessing_sections_ = true;
1546 if (pass == BEFORE_INPUT_SECTIONS_PASS
1547 && (*p)->after_input_sections())
1549 else if (pass == POSTPROCESSING_SECTIONS_PASS
1550 && (!(*p)->after_input_sections()
1551 || (*p)->type() == elfcpp::SHT_STRTAB))
1553 else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
1554 && (!(*p)->after_input_sections()
1555 || (*p)->type() != elfcpp::SHT_STRTAB))
1558 off = align_address(off, (*p)->addralign());
1559 (*p)->set_file_offset(off);
1560 (*p)->finalize_data_size();
1561 off += (*p)->data_size();
1563 // At this point the name must be set.
1564 if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
1565 this->namepool_.add((*p)->name(), false, NULL);
1570 // Set the section indexes of all the sections not associated with a
1574 Layout::set_section_indexes(unsigned int shndx)
1576 const bool output_is_object = parameters->options().relocatable();
1577 for (Section_list::iterator p = this->unattached_section_list_.begin();
1578 p != this->unattached_section_list_.end();
1581 // In a relocatable link, we already did group sections.
1582 if (output_is_object
1583 && (*p)->type() == elfcpp::SHT_GROUP)
1586 (*p)->set_out_shndx(shndx);
1592 // Set the section addresses according to the linker script. This is
1593 // only called when we see a SECTIONS clause. This returns the
1594 // program segment which should hold the file header and segment
1595 // headers, if any. It will return NULL if they should not be in a
1599 Layout::set_section_addresses_from_script(Symbol_table* symtab)
1601 Script_sections* ss = this->script_options_->script_sections();
1602 gold_assert(ss->saw_sections_clause());
1604 // Place each orphaned output section in the script.
1605 for (Section_list::iterator p = this->section_list_.begin();
1606 p != this->section_list_.end();
1609 if (!(*p)->found_in_sections_clause())
1610 ss->place_orphan(*p);
1613 return this->script_options_->set_section_addresses(symtab, this);
1616 // Count the local symbols in the regular symbol table and the dynamic
1617 // symbol table, and build the respective string pools.
1620 Layout::count_local_symbols(const Task* task,
1621 const Input_objects* input_objects)
1623 // First, figure out an upper bound on the number of symbols we'll
1624 // be inserting into each pool. This helps us create the pools with
1625 // the right size, to avoid unnecessary hashtable resizing.
1626 unsigned int symbol_count = 0;
1627 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1628 p != input_objects->relobj_end();
1630 symbol_count += (*p)->local_symbol_count();
1632 // Go from "upper bound" to "estimate." We overcount for two
1633 // reasons: we double-count symbols that occur in more than one
1634 // object file, and we count symbols that are dropped from the
1635 // output. Add it all together and assume we overcount by 100%.
1638 // We assume all symbols will go into both the sympool and dynpool.
1639 this->sympool_.reserve(symbol_count);
1640 this->dynpool_.reserve(symbol_count);
1642 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1643 p != input_objects->relobj_end();
1646 Task_lock_obj<Object> tlo(task, *p);
1647 (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
1651 // Create the symbol table sections. Here we also set the final
1652 // values of the symbols. At this point all the loadable sections are
1656 Layout::create_symtab_sections(const Input_objects* input_objects,
1657 Symbol_table* symtab,
1662 if (parameters->target().get_size() == 32)
1664 symsize = elfcpp::Elf_sizes<32>::sym_size;
1667 else if (parameters->target().get_size() == 64)
1669 symsize = elfcpp::Elf_sizes<64>::sym_size;
1676 off = align_address(off, align);
1677 off_t startoff = off;
1679 // Save space for the dummy symbol at the start of the section. We
1680 // never bother to write this out--it will just be left as zero.
1682 unsigned int local_symbol_index = 1;
1684 // Add STT_SECTION symbols for each Output section which needs one.
1685 for (Section_list::iterator p = this->section_list_.begin();
1686 p != this->section_list_.end();
1689 if (!(*p)->needs_symtab_index())
1690 (*p)->set_symtab_index(-1U);
1693 (*p)->set_symtab_index(local_symbol_index);
1694 ++local_symbol_index;
1699 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1700 p != input_objects->relobj_end();
1703 unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
1705 off += (index - local_symbol_index) * symsize;
1706 local_symbol_index = index;
1709 unsigned int local_symcount = local_symbol_index;
1710 gold_assert(local_symcount * symsize == off - startoff);
1713 size_t dyn_global_index;
1715 if (this->dynsym_section_ == NULL)
1718 dyn_global_index = 0;
1723 dyn_global_index = this->dynsym_section_->info();
1724 off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
1725 dynoff = this->dynsym_section_->offset() + locsize;
1726 dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
1727 gold_assert(static_cast<off_t>(dyncount * symsize)
1728 == this->dynsym_section_->data_size() - locsize);
1731 off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
1732 &this->sympool_, &local_symcount);
1734 if (!parameters->options().strip_all())
1736 this->sympool_.set_string_offsets();
1738 const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
1739 Output_section* osymtab = this->make_output_section(symtab_name,
1742 this->symtab_section_ = osymtab;
1744 Output_section_data* pos = new Output_data_fixed_space(off - startoff,
1746 osymtab->add_output_section_data(pos);
1748 const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
1749 Output_section* ostrtab = this->make_output_section(strtab_name,
1753 Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
1754 ostrtab->add_output_section_data(pstr);
1756 osymtab->set_file_offset(startoff);
1757 osymtab->finalize_data_size();
1758 osymtab->set_link_section(ostrtab);
1759 osymtab->set_info(local_symcount);
1760 osymtab->set_entsize(symsize);
1766 // Create the .shstrtab section, which holds the names of the
1767 // sections. At the time this is called, we have created all the
1768 // output sections except .shstrtab itself.
1771 Layout::create_shstrtab()
1773 // FIXME: We don't need to create a .shstrtab section if we are
1774 // stripping everything.
1776 const char* name = this->namepool_.add(".shstrtab", false, NULL);
1778 Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0);
1780 // We can't write out this section until we've set all the section
1781 // names, and we don't set the names of compressed output sections
1782 // until relocations are complete.
1783 os->set_after_input_sections();
1785 Output_section_data* posd = new Output_data_strtab(&this->namepool_);
1786 os->add_output_section_data(posd);
1791 // Create the section headers. SIZE is 32 or 64. OFF is the file
1795 Layout::create_shdrs(off_t* poff)
1797 Output_section_headers* oshdrs;
1798 oshdrs = new Output_section_headers(this,
1799 &this->segment_list_,
1800 &this->section_list_,
1801 &this->unattached_section_list_,
1803 off_t off = align_address(*poff, oshdrs->addralign());
1804 oshdrs->set_address_and_file_offset(0, off);
1805 off += oshdrs->data_size();
1807 this->section_headers_ = oshdrs;
1810 // Create the dynamic symbol table.
1813 Layout::create_dynamic_symtab(const Input_objects* input_objects,
1814 Symbol_table* symtab,
1815 Output_section **pdynstr,
1816 unsigned int* plocal_dynamic_count,
1817 std::vector<Symbol*>* pdynamic_symbols,
1818 Versions* pversions)
1820 // Count all the symbols in the dynamic symbol table, and set the
1821 // dynamic symbol indexes.
1823 // Skip symbol 0, which is always all zeroes.
1824 unsigned int index = 1;
1826 // Add STT_SECTION symbols for each Output section which needs one.
1827 for (Section_list::iterator p = this->section_list_.begin();
1828 p != this->section_list_.end();
1831 if (!(*p)->needs_dynsym_index())
1832 (*p)->set_dynsym_index(-1U);
1835 (*p)->set_dynsym_index(index);
1840 // Count the local symbols that need to go in the dynamic symbol table,
1841 // and set the dynamic symbol indexes.
1842 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1843 p != input_objects->relobj_end();
1846 unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
1850 unsigned int local_symcount = index;
1851 *plocal_dynamic_count = local_symcount;
1853 // FIXME: We have to tell set_dynsym_indexes whether the
1854 // -E/--export-dynamic option was used.
1855 index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
1856 &this->dynpool_, pversions);
1860 const int size = parameters->target().get_size();
1863 symsize = elfcpp::Elf_sizes<32>::sym_size;
1866 else if (size == 64)
1868 symsize = elfcpp::Elf_sizes<64>::sym_size;
1874 // Create the dynamic symbol table section.
1876 Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
1881 Output_section_data* odata = new Output_data_fixed_space(index * symsize,
1883 dynsym->add_output_section_data(odata);
1885 dynsym->set_info(local_symcount);
1886 dynsym->set_entsize(symsize);
1887 dynsym->set_addralign(align);
1889 this->dynsym_section_ = dynsym;
1891 Output_data_dynamic* const odyn = this->dynamic_data_;
1892 odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
1893 odyn->add_constant(elfcpp::DT_SYMENT, symsize);
1895 // Create the dynamic string table section.
1897 Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
1902 Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
1903 dynstr->add_output_section_data(strdata);
1905 dynsym->set_link_section(dynstr);
1906 this->dynamic_section_->set_link_section(dynstr);
1908 odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
1909 odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
1913 // Create the hash tables.
1915 // FIXME: We need an option to create a GNU hash table.
1917 unsigned char* phash;
1918 unsigned int hashlen;
1919 Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
1922 Output_section* hashsec = this->choose_output_section(NULL, ".hash",
1927 Output_section_data* hashdata = new Output_data_const_buffer(phash,
1930 hashsec->add_output_section_data(hashdata);
1932 hashsec->set_link_section(dynsym);
1933 hashsec->set_entsize(4);
1935 odyn->add_section_address(elfcpp::DT_HASH, hashsec);
1938 // Assign offsets to each local portion of the dynamic symbol table.
1941 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
1943 Output_section* dynsym = this->dynsym_section_;
1944 gold_assert(dynsym != NULL);
1946 off_t off = dynsym->offset();
1948 // Skip the dummy symbol at the start of the section.
1949 off += dynsym->entsize();
1951 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1952 p != input_objects->relobj_end();
1955 unsigned int count = (*p)->set_local_dynsym_offset(off);
1956 off += count * dynsym->entsize();
1960 // Create the version sections.
1963 Layout::create_version_sections(const Versions* versions,
1964 const Symbol_table* symtab,
1965 unsigned int local_symcount,
1966 const std::vector<Symbol*>& dynamic_symbols,
1967 const Output_section* dynstr)
1969 if (!versions->any_defs() && !versions->any_needs())
1972 switch (parameters->size_and_endianness())
1974 #ifdef HAVE_TARGET_32_LITTLE
1975 case Parameters::TARGET_32_LITTLE:
1976 this->sized_create_version_sections
1977 SELECT_SIZE_ENDIAN_NAME(32, false)(
1978 versions, symtab, local_symcount, dynamic_symbols, dynstr
1979 SELECT_SIZE_ENDIAN(32, false));
1982 #ifdef HAVE_TARGET_32_BIG
1983 case Parameters::TARGET_32_BIG:
1984 this->sized_create_version_sections
1985 SELECT_SIZE_ENDIAN_NAME(32, true)(
1986 versions, symtab, local_symcount, dynamic_symbols, dynstr
1987 SELECT_SIZE_ENDIAN(32, true));
1990 #ifdef HAVE_TARGET_64_LITTLE
1991 case Parameters::TARGET_64_LITTLE:
1992 this->sized_create_version_sections
1993 SELECT_SIZE_ENDIAN_NAME(64, false)(
1994 versions, symtab, local_symcount, dynamic_symbols, dynstr
1995 SELECT_SIZE_ENDIAN(64, false));
1998 #ifdef HAVE_TARGET_64_BIG
1999 case Parameters::TARGET_64_BIG:
2000 this->sized_create_version_sections
2001 SELECT_SIZE_ENDIAN_NAME(64, true)(
2002 versions, symtab, local_symcount, dynamic_symbols, dynstr
2003 SELECT_SIZE_ENDIAN(64, true));
2011 // Create the version sections, sized version.
2013 template<int size, bool big_endian>
2015 Layout::sized_create_version_sections(
2016 const Versions* versions,
2017 const Symbol_table* symtab,
2018 unsigned int local_symcount,
2019 const std::vector<Symbol*>& dynamic_symbols,
2020 const Output_section* dynstr
2023 Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
2024 elfcpp::SHT_GNU_versym,
2028 unsigned char* vbuf;
2030 versions->symbol_section_contents SELECT_SIZE_ENDIAN_NAME(size, big_endian)(
2031 symtab, &this->dynpool_, local_symcount, dynamic_symbols, &vbuf, &vsize
2032 SELECT_SIZE_ENDIAN(size, big_endian));
2034 Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2);
2036 vsec->add_output_section_data(vdata);
2037 vsec->set_entsize(2);
2038 vsec->set_link_section(this->dynsym_section_);
2040 Output_data_dynamic* const odyn = this->dynamic_data_;
2041 odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
2043 if (versions->any_defs())
2045 Output_section* vdsec;
2046 vdsec= this->choose_output_section(NULL, ".gnu.version_d",
2047 elfcpp::SHT_GNU_verdef,
2051 unsigned char* vdbuf;
2052 unsigned int vdsize;
2053 unsigned int vdentries;
2054 versions->def_section_contents SELECT_SIZE_ENDIAN_NAME(size, big_endian)(
2055 &this->dynpool_, &vdbuf, &vdsize, &vdentries
2056 SELECT_SIZE_ENDIAN(size, big_endian));
2058 Output_section_data* vddata = new Output_data_const_buffer(vdbuf,
2062 vdsec->add_output_section_data(vddata);
2063 vdsec->set_link_section(dynstr);
2064 vdsec->set_info(vdentries);
2066 odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
2067 odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
2070 if (versions->any_needs())
2072 Output_section* vnsec;
2073 vnsec = this->choose_output_section(NULL, ".gnu.version_r",
2074 elfcpp::SHT_GNU_verneed,
2078 unsigned char* vnbuf;
2079 unsigned int vnsize;
2080 unsigned int vnentries;
2081 versions->need_section_contents SELECT_SIZE_ENDIAN_NAME(size, big_endian)
2082 (&this->dynpool_, &vnbuf, &vnsize, &vnentries
2083 SELECT_SIZE_ENDIAN(size, big_endian));
2085 Output_section_data* vndata = new Output_data_const_buffer(vnbuf,
2089 vnsec->add_output_section_data(vndata);
2090 vnsec->set_link_section(dynstr);
2091 vnsec->set_info(vnentries);
2093 odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
2094 odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
2098 // Create the .interp section and PT_INTERP segment.
2101 Layout::create_interp(const Target* target)
2103 const char* interp = this->options_.dynamic_linker();
2106 interp = target->dynamic_linker();
2107 gold_assert(interp != NULL);
2110 size_t len = strlen(interp) + 1;
2112 Output_section_data* odata = new Output_data_const(interp, len, 1);
2114 Output_section* osec = this->choose_output_section(NULL, ".interp",
2115 elfcpp::SHT_PROGBITS,
2118 osec->add_output_section_data(odata);
2120 if (!this->script_options_->saw_phdrs_clause())
2122 Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP,
2124 oseg->add_initial_output_section(osec, elfcpp::PF_R);
2128 // Finish the .dynamic section and PT_DYNAMIC segment.
2131 Layout::finish_dynamic_section(const Input_objects* input_objects,
2132 const Symbol_table* symtab)
2134 if (!this->script_options_->saw_phdrs_clause())
2136 Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
2139 oseg->add_initial_output_section(this->dynamic_section_,
2140 elfcpp::PF_R | elfcpp::PF_W);
2143 Output_data_dynamic* const odyn = this->dynamic_data_;
2145 for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
2146 p != input_objects->dynobj_end();
2149 // FIXME: Handle --as-needed.
2150 odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
2153 if (parameters->options().shared())
2155 const char* soname = this->options_.soname();
2157 odyn->add_string(elfcpp::DT_SONAME, soname);
2160 // FIXME: Support --init and --fini.
2161 Symbol* sym = symtab->lookup("_init");
2162 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
2163 odyn->add_symbol(elfcpp::DT_INIT, sym);
2165 sym = symtab->lookup("_fini");
2166 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
2167 odyn->add_symbol(elfcpp::DT_FINI, sym);
2169 // FIXME: Support DT_INIT_ARRAY and DT_FINI_ARRAY.
2171 // Add a DT_RPATH entry if needed.
2172 const General_options::Dir_list& rpath(this->options_.rpath());
2175 std::string rpath_val;
2176 for (General_options::Dir_list::const_iterator p = rpath.begin();
2180 if (rpath_val.empty())
2181 rpath_val = p->name();
2184 // Eliminate duplicates.
2185 General_options::Dir_list::const_iterator q;
2186 for (q = rpath.begin(); q != p; ++q)
2187 if (q->name() == p->name())
2192 rpath_val += p->name();
2197 odyn->add_string(elfcpp::DT_RPATH, rpath_val);
2200 // Look for text segments that have dynamic relocations.
2201 bool have_textrel = false;
2202 if (!this->script_options_->saw_sections_clause())
2204 for (Segment_list::const_iterator p = this->segment_list_.begin();
2205 p != this->segment_list_.end();
2208 if (((*p)->flags() & elfcpp::PF_W) == 0
2209 && (*p)->dynamic_reloc_count() > 0)
2211 have_textrel = true;
2218 // We don't know the section -> segment mapping, so we are
2219 // conservative and just look for readonly sections with
2220 // relocations. If those sections wind up in writable segments,
2221 // then we have created an unnecessary DT_TEXTREL entry.
2222 for (Section_list::const_iterator p = this->section_list_.begin();
2223 p != this->section_list_.end();
2226 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
2227 && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
2228 && ((*p)->dynamic_reloc_count() > 0))
2230 have_textrel = true;
2236 // Add a DT_FLAGS entry. We add it even if no flags are set so that
2237 // post-link tools can easily modify these flags if desired.
2238 unsigned int flags = 0;
2241 // Add a DT_TEXTREL for compatibility with older loaders.
2242 odyn->add_constant(elfcpp::DT_TEXTREL, 0);
2243 flags |= elfcpp::DF_TEXTREL;
2245 if (parameters->options().shared() && this->has_static_tls())
2246 flags |= elfcpp::DF_STATIC_TLS;
2247 odyn->add_constant(elfcpp::DT_FLAGS, flags);
2250 // The mapping of .gnu.linkonce section names to real section names.
2252 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
2253 const Layout::Linkonce_mapping Layout::linkonce_mapping[] =
2255 MAPPING_INIT("d.rel.ro", ".data.rel.ro"), // Must be before "d".
2256 MAPPING_INIT("t", ".text"),
2257 MAPPING_INIT("r", ".rodata"),
2258 MAPPING_INIT("d", ".data"),
2259 MAPPING_INIT("b", ".bss"),
2260 MAPPING_INIT("s", ".sdata"),
2261 MAPPING_INIT("sb", ".sbss"),
2262 MAPPING_INIT("s2", ".sdata2"),
2263 MAPPING_INIT("sb2", ".sbss2"),
2264 MAPPING_INIT("wi", ".debug_info"),
2265 MAPPING_INIT("td", ".tdata"),
2266 MAPPING_INIT("tb", ".tbss"),
2267 MAPPING_INIT("lr", ".lrodata"),
2268 MAPPING_INIT("l", ".ldata"),
2269 MAPPING_INIT("lb", ".lbss"),
2273 const int Layout::linkonce_mapping_count =
2274 sizeof(Layout::linkonce_mapping) / sizeof(Layout::linkonce_mapping[0]);
2276 // Return the name of the output section to use for a .gnu.linkonce
2277 // section. This is based on the default ELF linker script of the old
2278 // GNU linker. For example, we map a name like ".gnu.linkonce.t.foo"
2279 // to ".text". Set *PLEN to the length of the name. *PLEN is
2280 // initialized to the length of NAME.
2283 Layout::linkonce_output_name(const char* name, size_t *plen)
2285 const char* s = name + sizeof(".gnu.linkonce") - 1;
2289 const Linkonce_mapping* plm = linkonce_mapping;
2290 for (int i = 0; i < linkonce_mapping_count; ++i, ++plm)
2292 if (strncmp(s, plm->from, plm->fromlen) == 0 && s[plm->fromlen] == '.')
2301 // Choose the output section name to use given an input section name.
2302 // Set *PLEN to the length of the name. *PLEN is initialized to the
2306 Layout::output_section_name(const char* name, size_t* plen)
2308 if (Layout::is_linkonce(name))
2310 // .gnu.linkonce sections are laid out as though they were named
2311 // for the sections are placed into.
2312 return Layout::linkonce_output_name(name, plen);
2315 // gcc 4.3 generates the following sorts of section names when it
2316 // needs a section name specific to a function:
2322 // .data.rel.local.FN
2324 // .data.rel.ro.local.FN
2331 // The GNU linker maps all of those to the part before the .FN,
2332 // except that .data.rel.local.FN is mapped to .data, and
2333 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
2334 // beginning with .data.rel.ro.local are grouped together.
2336 // For an anonymous namespace, the string FN can contain a '.'.
2338 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
2339 // GNU linker maps to .rodata.
2341 // The .data.rel.ro sections enable a security feature triggered by
2342 // the -z relro option. Section which need to be relocated at
2343 // program startup time but which may be readonly after startup are
2344 // grouped into .data.rel.ro. They are then put into a PT_GNU_RELRO
2345 // segment. The dynamic linker will make that segment writable,
2346 // perform relocations, and then make it read-only. FIXME: We do
2347 // not yet implement this optimization.
2349 // It is hard to handle this in a principled way.
2351 // These are the rules we follow:
2353 // If the section name has no initial '.', or no dot other than an
2354 // initial '.', we use the name unchanged (i.e., "mysection" and
2355 // ".text" are unchanged).
2357 // If the name starts with ".data.rel.ro" we use ".data.rel.ro".
2359 // Otherwise, we drop the second '.' and everything that comes after
2360 // it (i.e., ".text.XXX" becomes ".text").
2362 const char* s = name;
2366 const char* sdot = strchr(s, '.');
2370 const char* const data_rel_ro = ".data.rel.ro";
2371 if (strncmp(name, data_rel_ro, strlen(data_rel_ro)) == 0)
2373 *plen = strlen(data_rel_ro);
2377 *plen = sdot - name;
2381 // Record the signature of a comdat section, and return whether to
2382 // include it in the link. If GROUP is true, this is a regular
2383 // section group. If GROUP is false, this is a group signature
2384 // derived from the name of a linkonce section. We want linkonce
2385 // signatures and group signatures to block each other, but we don't
2386 // want a linkonce signature to block another linkonce signature.
2389 Layout::add_comdat(const char* signature, bool group)
2391 std::string sig(signature);
2392 std::pair<Signatures::iterator, bool> ins(
2393 this->signatures_.insert(std::make_pair(sig, group)));
2397 // This is the first time we've seen this signature.
2401 if (ins.first->second)
2403 // We've already seen a real section group with this signature.
2408 // This is a real section group, and we've already seen a
2409 // linkonce section with this signature. Record that we've seen
2410 // a section group, and don't include this section group.
2411 ins.first->second = true;
2416 // We've already seen a linkonce section and this is a linkonce
2417 // section. These don't block each other--this may be the same
2418 // symbol name with different section types.
2423 // Store the allocated sections into the section list.
2426 Layout::get_allocated_sections(Section_list* section_list) const
2428 for (Section_list::const_iterator p = this->section_list_.begin();
2429 p != this->section_list_.end();
2431 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
2432 section_list->push_back(*p);
2435 // Create an output segment.
2438 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
2440 gold_assert(!parameters->options().relocatable());
2441 Output_segment* oseg = new Output_segment(type, flags);
2442 this->segment_list_.push_back(oseg);
2446 // Write out the Output_sections. Most won't have anything to write,
2447 // since most of the data will come from input sections which are
2448 // handled elsewhere. But some Output_sections do have Output_data.
2451 Layout::write_output_sections(Output_file* of) const
2453 for (Section_list::const_iterator p = this->section_list_.begin();
2454 p != this->section_list_.end();
2457 if (!(*p)->after_input_sections())
2462 // Write out data not associated with a section or the symbol table.
2465 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
2467 if (!parameters->options().strip_all())
2469 const Output_section* symtab_section = this->symtab_section_;
2470 for (Section_list::const_iterator p = this->section_list_.begin();
2471 p != this->section_list_.end();
2474 if ((*p)->needs_symtab_index())
2476 gold_assert(symtab_section != NULL);
2477 unsigned int index = (*p)->symtab_index();
2478 gold_assert(index > 0 && index != -1U);
2479 off_t off = (symtab_section->offset()
2480 + index * symtab_section->entsize());
2481 symtab->write_section_symbol(*p, of, off);
2486 const Output_section* dynsym_section = this->dynsym_section_;
2487 for (Section_list::const_iterator p = this->section_list_.begin();
2488 p != this->section_list_.end();
2491 if ((*p)->needs_dynsym_index())
2493 gold_assert(dynsym_section != NULL);
2494 unsigned int index = (*p)->dynsym_index();
2495 gold_assert(index > 0 && index != -1U);
2496 off_t off = (dynsym_section->offset()
2497 + index * dynsym_section->entsize());
2498 symtab->write_section_symbol(*p, of, off);
2502 // Write out the Output_data which are not in an Output_section.
2503 for (Data_list::const_iterator p = this->special_output_list_.begin();
2504 p != this->special_output_list_.end();
2509 // Write out the Output_sections which can only be written after the
2510 // input sections are complete.
2513 Layout::write_sections_after_input_sections(Output_file* of)
2515 // Determine the final section offsets, and thus the final output
2516 // file size. Note we finalize the .shstrab last, to allow the
2517 // after_input_section sections to modify their section-names before
2519 if (this->any_postprocessing_sections_)
2521 off_t off = this->output_file_size_;
2522 off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
2524 // Now that we've finalized the names, we can finalize the shstrab.
2526 this->set_section_offsets(off,
2527 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
2529 if (off > this->output_file_size_)
2532 this->output_file_size_ = off;
2536 for (Section_list::const_iterator p = this->section_list_.begin();
2537 p != this->section_list_.end();
2540 if ((*p)->after_input_sections())
2544 this->section_headers_->write(of);
2547 // Write out a binary file. This is called after the link is
2548 // complete. IN is the temporary output file we used to generate the
2549 // ELF code. We simply walk through the segments, read them from
2550 // their file offset in IN, and write them to their load address in
2551 // the output file. FIXME: with a bit more work, we could support
2552 // S-records and/or Intel hex format here.
2555 Layout::write_binary(Output_file* in) const
2557 gold_assert(this->options_.oformat()
2558 == General_options::OBJECT_FORMAT_BINARY);
2560 // Get the size of the binary file.
2561 uint64_t max_load_address = 0;
2562 for (Segment_list::const_iterator p = this->segment_list_.begin();
2563 p != this->segment_list_.end();
2566 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
2568 uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
2569 if (max_paddr > max_load_address)
2570 max_load_address = max_paddr;
2574 Output_file out(parameters->options().output_file_name());
2575 out.open(max_load_address);
2577 for (Segment_list::const_iterator p = this->segment_list_.begin();
2578 p != this->segment_list_.end();
2581 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
2583 const unsigned char* vin = in->get_input_view((*p)->offset(),
2585 unsigned char* vout = out.get_output_view((*p)->paddr(),
2587 memcpy(vout, vin, (*p)->filesz());
2588 out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
2589 in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
2596 // Print statistical information to stderr. This is used for --stats.
2599 Layout::print_stats() const
2601 this->namepool_.print_stats("section name pool");
2602 this->sympool_.print_stats("output symbol name pool");
2603 this->dynpool_.print_stats("dynamic name pool");
2605 for (Section_list::const_iterator p = this->section_list_.begin();
2606 p != this->section_list_.end();
2608 (*p)->print_merge_stats();
2611 // Write_sections_task methods.
2613 // We can always run this task.
2616 Write_sections_task::is_runnable()
2621 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
2625 Write_sections_task::locks(Task_locker* tl)
2627 tl->add(this, this->output_sections_blocker_);
2628 tl->add(this, this->final_blocker_);
2631 // Run the task--write out the data.
2634 Write_sections_task::run(Workqueue*)
2636 this->layout_->write_output_sections(this->of_);
2639 // Write_data_task methods.
2641 // We can always run this task.
2644 Write_data_task::is_runnable()
2649 // We need to unlock FINAL_BLOCKER when finished.
2652 Write_data_task::locks(Task_locker* tl)
2654 tl->add(this, this->final_blocker_);
2657 // Run the task--write out the data.
2660 Write_data_task::run(Workqueue*)
2662 this->layout_->write_data(this->symtab_, this->of_);
2665 // Write_symbols_task methods.
2667 // We can always run this task.
2670 Write_symbols_task::is_runnable()
2675 // We need to unlock FINAL_BLOCKER when finished.
2678 Write_symbols_task::locks(Task_locker* tl)
2680 tl->add(this, this->final_blocker_);
2683 // Run the task--write out the symbols.
2686 Write_symbols_task::run(Workqueue*)
2688 this->symtab_->write_globals(this->input_objects_, this->sympool_,
2689 this->dynpool_, this->of_);
2692 // Write_after_input_sections_task methods.
2694 // We can only run this task after the input sections have completed.
2697 Write_after_input_sections_task::is_runnable()
2699 if (this->input_sections_blocker_->is_blocked())
2700 return this->input_sections_blocker_;
2704 // We need to unlock FINAL_BLOCKER when finished.
2707 Write_after_input_sections_task::locks(Task_locker* tl)
2709 tl->add(this, this->final_blocker_);
2715 Write_after_input_sections_task::run(Workqueue*)
2717 this->layout_->write_sections_after_input_sections(this->of_);
2720 // Close_task_runner methods.
2722 // Run the task--close the file.
2725 Close_task_runner::run(Workqueue*, const Task*)
2727 // If we've been asked to create a binary file, we do so here.
2728 if (this->options_->oformat() != General_options::OBJECT_FORMAT_ELF)
2729 this->layout_->write_binary(this->of_);
2734 // Instantiate the templates we need. We could use the configure
2735 // script to restrict this to only the ones for implemented targets.
2737 #ifdef HAVE_TARGET_32_LITTLE
2740 Layout::layout<32, false>(Sized_relobj<32, false>* object, unsigned int shndx,
2742 const elfcpp::Shdr<32, false>& shdr,
2743 unsigned int, unsigned int, off_t*);
2746 #ifdef HAVE_TARGET_32_BIG
2749 Layout::layout<32, true>(Sized_relobj<32, true>* object, unsigned int shndx,
2751 const elfcpp::Shdr<32, true>& shdr,
2752 unsigned int, unsigned int, off_t*);
2755 #ifdef HAVE_TARGET_64_LITTLE
2758 Layout::layout<64, false>(Sized_relobj<64, false>* object, unsigned int shndx,
2760 const elfcpp::Shdr<64, false>& shdr,
2761 unsigned int, unsigned int, off_t*);
2764 #ifdef HAVE_TARGET_64_BIG
2767 Layout::layout<64, true>(Sized_relobj<64, true>* object, unsigned int shndx,
2769 const elfcpp::Shdr<64, true>& shdr,
2770 unsigned int, unsigned int, off_t*);
2773 #ifdef HAVE_TARGET_32_LITTLE
2776 Layout::layout_reloc<32, false>(Sized_relobj<32, false>* object,
2777 unsigned int reloc_shndx,
2778 const elfcpp::Shdr<32, false>& shdr,
2779 Output_section* data_section,
2780 Relocatable_relocs* rr);
2783 #ifdef HAVE_TARGET_32_BIG
2786 Layout::layout_reloc<32, true>(Sized_relobj<32, true>* object,
2787 unsigned int reloc_shndx,
2788 const elfcpp::Shdr<32, true>& shdr,
2789 Output_section* data_section,
2790 Relocatable_relocs* rr);
2793 #ifdef HAVE_TARGET_64_LITTLE
2796 Layout::layout_reloc<64, false>(Sized_relobj<64, false>* object,
2797 unsigned int reloc_shndx,
2798 const elfcpp::Shdr<64, false>& shdr,
2799 Output_section* data_section,
2800 Relocatable_relocs* rr);
2803 #ifdef HAVE_TARGET_64_BIG
2806 Layout::layout_reloc<64, true>(Sized_relobj<64, true>* object,
2807 unsigned int reloc_shndx,
2808 const elfcpp::Shdr<64, true>& shdr,
2809 Output_section* data_section,
2810 Relocatable_relocs* rr);
2813 #ifdef HAVE_TARGET_32_LITTLE
2816 Layout::layout_group<32, false>(Symbol_table* symtab,
2817 Sized_relobj<32, false>* object,
2819 const char* group_section_name,
2820 const char* signature,
2821 const elfcpp::Shdr<32, false>& shdr,
2822 const elfcpp::Elf_Word* contents);
2825 #ifdef HAVE_TARGET_32_BIG
2828 Layout::layout_group<32, true>(Symbol_table* symtab,
2829 Sized_relobj<32, true>* object,
2831 const char* group_section_name,
2832 const char* signature,
2833 const elfcpp::Shdr<32, true>& shdr,
2834 const elfcpp::Elf_Word* contents);
2837 #ifdef HAVE_TARGET_64_LITTLE
2840 Layout::layout_group<64, false>(Symbol_table* symtab,
2841 Sized_relobj<64, false>* object,
2843 const char* group_section_name,
2844 const char* signature,
2845 const elfcpp::Shdr<64, false>& shdr,
2846 const elfcpp::Elf_Word* contents);
2849 #ifdef HAVE_TARGET_64_BIG
2852 Layout::layout_group<64, true>(Symbol_table* symtab,
2853 Sized_relobj<64, true>* object,
2855 const char* group_section_name,
2856 const char* signature,
2857 const elfcpp::Shdr<64, true>& shdr,
2858 const elfcpp::Elf_Word* contents);
2861 #ifdef HAVE_TARGET_32_LITTLE
2864 Layout::layout_eh_frame<32, false>(Sized_relobj<32, false>* object,
2865 const unsigned char* symbols,
2867 const unsigned char* symbol_names,
2868 off_t symbol_names_size,
2870 const elfcpp::Shdr<32, false>& shdr,
2871 unsigned int reloc_shndx,
2872 unsigned int reloc_type,
2876 #ifdef HAVE_TARGET_32_BIG
2879 Layout::layout_eh_frame<32, true>(Sized_relobj<32, true>* object,
2880 const unsigned char* symbols,
2882 const unsigned char* symbol_names,
2883 off_t symbol_names_size,
2885 const elfcpp::Shdr<32, true>& shdr,
2886 unsigned int reloc_shndx,
2887 unsigned int reloc_type,
2891 #ifdef HAVE_TARGET_64_LITTLE
2894 Layout::layout_eh_frame<64, false>(Sized_relobj<64, false>* object,
2895 const unsigned char* symbols,
2897 const unsigned char* symbol_names,
2898 off_t symbol_names_size,
2900 const elfcpp::Shdr<64, false>& shdr,
2901 unsigned int reloc_shndx,
2902 unsigned int reloc_type,
2906 #ifdef HAVE_TARGET_64_BIG
2909 Layout::layout_eh_frame<64, true>(Sized_relobj<64, true>* object,
2910 const unsigned char* symbols,
2912 const unsigned char* symbol_names,
2913 off_t symbol_names_size,
2915 const elfcpp::Shdr<64, true>& shdr,
2916 unsigned int reloc_shndx,
2917 unsigned int reloc_type,
2921 } // End namespace gold.