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_,
57 // Now we know the final size of the output file and we know where
58 // each piece of information goes.
59 Output_file* of = new Output_file(parameters->output_file_name());
60 if (this->options_.output_format() != General_options::OBJECT_FORMAT_ELF)
61 of->set_is_temporary();
64 // Queue up the final set of tasks.
65 gold::queue_final_tasks(this->options_, this->input_objects_,
66 this->symtab_, this->layout_, workqueue, of);
71 Layout::Layout(const General_options& options, Script_options* script_options)
72 : options_(options), script_options_(script_options), namepool_(),
73 sympool_(), dynpool_(), signatures_(),
74 section_name_map_(), segment_list_(), section_list_(),
75 unattached_section_list_(), special_output_list_(),
76 section_headers_(NULL), tls_segment_(NULL), symtab_section_(NULL),
77 dynsym_section_(NULL), dynamic_section_(NULL), dynamic_data_(NULL),
78 eh_frame_section_(NULL), group_signatures_(), output_file_size_(-1),
79 input_requires_executable_stack_(false),
80 input_with_gnu_stack_note_(false),
81 input_without_gnu_stack_note_(false),
82 has_static_tls_(false),
83 any_postprocessing_sections_(false)
85 // Make space for more than enough segments for a typical file.
86 // This is just for efficiency--it's OK if we wind up needing more.
87 this->segment_list_.reserve(12);
89 // We expect two unattached Output_data objects: the file header and
90 // the segment headers.
91 this->special_output_list_.reserve(2);
94 // Hash a key we use to look up an output section mapping.
97 Layout::Hash_key::operator()(const Layout::Key& k) const
99 return k.first + k.second.first + k.second.second;
102 // Return whether PREFIX is a prefix of STR.
105 is_prefix_of(const char* prefix, const char* str)
107 return strncmp(prefix, str, strlen(prefix)) == 0;
110 // Returns whether the given section is in the list of
111 // debug-sections-used-by-some-version-of-gdb. Currently,
112 // we've checked versions of gdb up to and including 6.7.1.
114 static const char* gdb_sections[] =
116 // ".debug_aranges", // not used by gdb as of 6.7.1
122 // ".debug_pubnames", // not used by gdb as of 6.7.1
128 is_gdb_debug_section(const char* str)
130 // We can do this faster: binary search or a hashtable. But why bother?
131 for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
132 if (strcmp(str, gdb_sections[i]) == 0)
137 // Whether to include this section in the link.
139 template<int size, bool big_endian>
141 Layout::include_section(Sized_relobj<size, big_endian>*, const char* name,
142 const elfcpp::Shdr<size, big_endian>& shdr)
144 switch (shdr.get_sh_type())
146 case elfcpp::SHT_NULL:
147 case elfcpp::SHT_SYMTAB:
148 case elfcpp::SHT_DYNSYM:
149 case elfcpp::SHT_STRTAB:
150 case elfcpp::SHT_HASH:
151 case elfcpp::SHT_DYNAMIC:
152 case elfcpp::SHT_SYMTAB_SHNDX:
155 case elfcpp::SHT_RELA:
156 case elfcpp::SHT_REL:
157 case elfcpp::SHT_GROUP:
158 // For a relocatable link these should be handled elsewhere.
159 gold_assert(!parameters->output_is_object());
162 case elfcpp::SHT_PROGBITS:
163 if (parameters->strip_debug()
164 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
166 // Debugging sections can only be recognized by name.
167 if (is_prefix_of(".debug", name)
168 || is_prefix_of(".gnu.linkonce.wi.", name)
169 || is_prefix_of(".line", name)
170 || is_prefix_of(".stab", name))
173 if (parameters->strip_debug_gdb()
174 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
176 // Debugging sections can only be recognized by name.
177 if (is_prefix_of(".debug", name)
178 && !is_gdb_debug_section(name))
188 // Return an output section named NAME, or NULL if there is none.
191 Layout::find_output_section(const char* name) const
193 for (Section_list::const_iterator p = this->section_list_.begin();
194 p != this->section_list_.end();
196 if (strcmp((*p)->name(), name) == 0)
201 // Return an output segment of type TYPE, with segment flags SET set
202 // and segment flags CLEAR clear. Return NULL if there is none.
205 Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
206 elfcpp::Elf_Word clear) const
208 for (Segment_list::const_iterator p = this->segment_list_.begin();
209 p != this->segment_list_.end();
211 if (static_cast<elfcpp::PT>((*p)->type()) == type
212 && ((*p)->flags() & set) == set
213 && ((*p)->flags() & clear) == 0)
218 // Return the output section to use for section NAME with type TYPE
219 // and section flags FLAGS. NAME must be canonicalized in the string
220 // pool, and NAME_KEY is the key.
223 Layout::get_output_section(const char* name, Stringpool::Key name_key,
224 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags)
226 const Key key(name_key, std::make_pair(type, flags));
227 const std::pair<Key, Output_section*> v(key, NULL);
228 std::pair<Section_name_map::iterator, bool> ins(
229 this->section_name_map_.insert(v));
232 return ins.first->second;
235 // This is the first time we've seen this name/type/flags
237 Output_section* os = this->make_output_section(name, type, flags);
238 ins.first->second = os;
243 // Pick the output section to use for section NAME, in input file
244 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
245 // linker created section. ADJUST_NAME is true if we should apply the
246 // standard name mappings in Layout::output_section_name. This will
247 // return NULL if the input section should be discarded.
250 Layout::choose_output_section(const Relobj* relobj, const char* name,
251 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
254 // We should ignore some flags. FIXME: This will need some
255 // adjustment for ld -r.
256 flags &= ~ (elfcpp::SHF_INFO_LINK
257 | elfcpp::SHF_LINK_ORDER
260 | elfcpp::SHF_STRINGS);
262 if (this->script_options_->saw_sections_clause())
264 // We are using a SECTIONS clause, so the output section is
265 // chosen based only on the name.
267 Script_sections* ss = this->script_options_->script_sections();
268 const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
269 Output_section** output_section_slot;
270 name = ss->output_section_name(file_name, name, &output_section_slot);
273 // The SECTIONS clause says to discard this input section.
277 // If this is an orphan section--one not mentioned in the linker
278 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
279 // default processing below.
281 if (output_section_slot != NULL)
283 if (*output_section_slot != NULL)
284 return *output_section_slot;
286 // We don't put sections found in the linker script into
287 // SECTION_NAME_MAP_. That keeps us from getting confused
288 // if an orphan section is mapped to a section with the same
289 // name as one in the linker script.
291 name = this->namepool_.add(name, false, NULL);
293 Output_section* os = this->make_output_section(name, type, flags);
294 os->set_found_in_sections_clause();
295 *output_section_slot = os;
300 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
302 // Turn NAME from the name of the input section into the name of the
305 size_t len = strlen(name);
306 if (adjust_name && !parameters->output_is_object())
307 name = Layout::output_section_name(name, &len);
309 Stringpool::Key name_key;
310 name = this->namepool_.add_with_length(name, len, true, &name_key);
312 // Find or make the output section. The output section is selected
313 // based on the section name, type, and flags.
314 return this->get_output_section(name, name_key, type, flags);
317 // Return the output section to use for input section SHNDX, with name
318 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
319 // index of a relocation section which applies to this section, or 0
320 // if none, or -1U if more than one. RELOC_TYPE is the type of the
321 // relocation section if there is one. Set *OFF to the offset of this
322 // input section without the output section. Return NULL if the
323 // section should be discarded. Set *OFF to -1 if the section
324 // contents should not be written directly to the output file, but
325 // will instead receive special handling.
327 template<int size, bool big_endian>
329 Layout::layout(Sized_relobj<size, big_endian>* object, unsigned int shndx,
330 const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
331 unsigned int reloc_shndx, unsigned int, off_t* off)
333 if (!this->include_section(object, name, shdr))
338 // In a relocatable link a grouped section must not be combined with
339 // any other sections.
340 if (parameters->output_is_object()
341 && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
343 name = this->namepool_.add(name, true, NULL);
344 os = this->make_output_section(name, shdr.get_sh_type(),
345 shdr.get_sh_flags());
349 os = this->choose_output_section(object, name, shdr.get_sh_type(),
350 shdr.get_sh_flags(), true);
355 // FIXME: Handle SHF_LINK_ORDER somewhere.
357 *off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
358 this->script_options_->saw_sections_clause());
363 // Handle a relocation section when doing a relocatable link.
365 template<int size, bool big_endian>
367 Layout::layout_reloc(Sized_relobj<size, big_endian>* object,
369 const elfcpp::Shdr<size, big_endian>& shdr,
370 Output_section* data_section,
371 Relocatable_relocs* rr)
373 gold_assert(parameters->output_is_object());
375 int sh_type = shdr.get_sh_type();
378 if (sh_type == elfcpp::SHT_REL)
380 else if (sh_type == elfcpp::SHT_RELA)
384 name += data_section->name();
386 Output_section* os = this->choose_output_section(object, name.c_str(),
391 os->set_should_link_to_symtab();
392 os->set_info_section(data_section);
394 Output_section_data* posd;
395 if (sh_type == elfcpp::SHT_REL)
397 os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
398 posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
402 else if (sh_type == elfcpp::SHT_RELA)
404 os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
405 posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
412 os->add_output_section_data(posd);
413 rr->set_output_data(posd);
418 // Handle a group section when doing a relocatable link.
420 template<int size, bool big_endian>
422 Layout::layout_group(Symbol_table* symtab,
423 Sized_relobj<size, big_endian>* object,
425 const char* group_section_name,
426 const char* signature,
427 const elfcpp::Shdr<size, big_endian>& shdr,
428 const elfcpp::Elf_Word* contents)
430 gold_assert(parameters->output_is_object());
431 gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
432 group_section_name = this->namepool_.add(group_section_name, true, NULL);
433 Output_section* os = this->make_output_section(group_section_name,
435 shdr.get_sh_flags());
437 // We need to find a symbol with the signature in the symbol table.
438 // If we don't find one now, we need to look again later.
439 Symbol* sym = symtab->lookup(signature, NULL);
441 os->set_info_symndx(sym);
444 // We will wind up using a symbol whose name is the signature.
445 // So just put the signature in the symbol name pool to save it.
446 signature = symtab->canonicalize_name(signature);
447 this->group_signatures_.push_back(Group_signature(os, signature));
450 os->set_should_link_to_symtab();
453 section_size_type entry_count =
454 convert_to_section_size_type(shdr.get_sh_size() / 4);
455 Output_section_data* posd =
456 new Output_data_group<size, big_endian>(object, entry_count, contents);
457 os->add_output_section_data(posd);
460 // Special GNU handling of sections name .eh_frame. They will
461 // normally hold exception frame data as defined by the C++ ABI
462 // (http://codesourcery.com/cxx-abi/).
464 template<int size, bool big_endian>
466 Layout::layout_eh_frame(Sized_relobj<size, big_endian>* object,
467 const unsigned char* symbols,
469 const unsigned char* symbol_names,
470 off_t symbol_names_size,
472 const elfcpp::Shdr<size, big_endian>& shdr,
473 unsigned int reloc_shndx, unsigned int reloc_type,
476 gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS);
477 gold_assert(shdr.get_sh_flags() == elfcpp::SHF_ALLOC);
479 const char* const name = ".eh_frame";
480 Output_section* os = this->choose_output_section(object,
482 elfcpp::SHT_PROGBITS,
488 if (this->eh_frame_section_ == NULL)
490 this->eh_frame_section_ = os;
491 this->eh_frame_data_ = new Eh_frame();
492 os->add_output_section_data(this->eh_frame_data_);
494 if (this->options_.create_eh_frame_hdr())
496 Output_section* hdr_os =
497 this->choose_output_section(NULL,
499 elfcpp::SHT_PROGBITS,
505 Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
506 this->eh_frame_data_);
507 hdr_os->add_output_section_data(hdr_posd);
509 hdr_os->set_after_input_sections();
511 if (!this->script_options_->saw_phdrs_clause())
513 Output_segment* hdr_oseg;
514 hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
516 hdr_oseg->add_output_section(hdr_os, elfcpp::PF_R);
519 this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
524 gold_assert(this->eh_frame_section_ == os);
526 if (this->eh_frame_data_->add_ehframe_input_section(object,
537 // We couldn't handle this .eh_frame section for some reason.
538 // Add it as a normal section.
539 bool saw_sections_clause = this->script_options_->saw_sections_clause();
540 *off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
541 saw_sections_clause);
547 // Add POSD to an output section using NAME, TYPE, and FLAGS.
550 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
551 elfcpp::Elf_Xword flags,
552 Output_section_data* posd)
554 Output_section* os = this->choose_output_section(NULL, name, type, flags,
557 os->add_output_section_data(posd);
560 // Map section flags to segment flags.
563 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
565 elfcpp::Elf_Word ret = elfcpp::PF_R;
566 if ((flags & elfcpp::SHF_WRITE) != 0)
568 if ((flags & elfcpp::SHF_EXECINSTR) != 0)
573 // Sometimes we compress sections. This is typically done for
574 // sections that are not part of normal program execution (such as
575 // .debug_* sections), and where the readers of these sections know
576 // how to deal with compressed sections. (To make it easier for them,
577 // we will rename the ouput section in such cases from .foo to
578 // .foo.zlib.nnnn, where nnnn is the uncompressed size.) This routine
579 // doesn't say for certain whether we'll compress -- it depends on
580 // commandline options as well -- just whether this section is a
581 // candidate for compression.
584 is_compressible_debug_section(const char* secname)
586 return (strncmp(secname, ".debug", sizeof(".debug") - 1) == 0);
589 // Make a new Output_section, and attach it to segments as
593 Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
594 elfcpp::Elf_Xword flags)
597 if ((flags & elfcpp::SHF_ALLOC) == 0
598 && this->options_.compress_debug_sections()
599 && is_compressible_debug_section(name))
600 os = new Output_compressed_section(&this->options_, name, type, flags);
602 os = new Output_section(name, type, flags);
604 this->section_list_.push_back(os);
606 if ((flags & elfcpp::SHF_ALLOC) == 0)
607 this->unattached_section_list_.push_back(os);
610 if (parameters->output_is_object())
613 // If we have a SECTIONS clause, we can't handle the attachment
614 // to segments until after we've seen all the sections.
615 if (this->script_options_->saw_sections_clause())
618 gold_assert(!this->script_options_->saw_phdrs_clause());
620 // This output section goes into a PT_LOAD segment.
622 elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
624 // In general the only thing we really care about for PT_LOAD
625 // segments is whether or not they are writable, so that is how
626 // we search for them. People who need segments sorted on some
627 // other basis will have to use a linker script.
629 Segment_list::const_iterator p;
630 for (p = this->segment_list_.begin();
631 p != this->segment_list_.end();
634 if ((*p)->type() == elfcpp::PT_LOAD
635 && ((*p)->flags() & elfcpp::PF_W) == (seg_flags & elfcpp::PF_W))
637 // If -Tbss was specified, we need to separate the data
639 if (this->options_.user_set_bss_segment_address())
641 if ((type == elfcpp::SHT_NOBITS)
642 == (*p)->has_any_data_sections())
646 (*p)->add_output_section(os, seg_flags);
651 if (p == this->segment_list_.end())
653 Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
655 oseg->add_output_section(os, seg_flags);
658 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
660 if (type == elfcpp::SHT_NOTE)
662 // See if we already have an equivalent PT_NOTE segment.
663 for (p = this->segment_list_.begin();
664 p != segment_list_.end();
667 if ((*p)->type() == elfcpp::PT_NOTE
668 && (((*p)->flags() & elfcpp::PF_W)
669 == (seg_flags & elfcpp::PF_W)))
671 (*p)->add_output_section(os, seg_flags);
676 if (p == this->segment_list_.end())
678 Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
680 oseg->add_output_section(os, seg_flags);
684 // If we see a loadable SHF_TLS section, we create a PT_TLS
685 // segment. There can only be one such segment.
686 if ((flags & elfcpp::SHF_TLS) != 0)
688 if (this->tls_segment_ == NULL)
689 this->tls_segment_ = this->make_output_segment(elfcpp::PT_TLS,
691 this->tls_segment_->add_output_section(os, seg_flags);
698 // Return the number of segments we expect to see.
701 Layout::expected_segment_count() const
703 size_t ret = this->segment_list_.size();
705 // If we didn't see a SECTIONS clause in a linker script, we should
706 // already have the complete list of segments. Otherwise we ask the
707 // SECTIONS clause how many segments it expects, and add in the ones
708 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
710 if (!this->script_options_->saw_sections_clause())
714 const Script_sections* ss = this->script_options_->script_sections();
715 return ret + ss->expected_segment_count(this);
719 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
720 // is whether we saw a .note.GNU-stack section in the object file.
721 // GNU_STACK_FLAGS is the section flags. The flags give the
722 // protection required for stack memory. We record this in an
723 // executable as a PT_GNU_STACK segment. If an object file does not
724 // have a .note.GNU-stack segment, we must assume that it is an old
725 // object. On some targets that will force an executable stack.
728 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags)
731 this->input_without_gnu_stack_note_ = true;
734 this->input_with_gnu_stack_note_ = true;
735 if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
736 this->input_requires_executable_stack_ = true;
740 // Create the dynamic sections which are needed before we read the
744 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
746 if (parameters->doing_static_link())
749 this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
752 | elfcpp::SHF_WRITE),
755 symtab->define_in_output_data("_DYNAMIC", NULL, this->dynamic_section_, 0, 0,
756 elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
757 elfcpp::STV_HIDDEN, 0, false, false);
759 this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_);
761 this->dynamic_section_->add_output_section_data(this->dynamic_data_);
764 // For each output section whose name can be represented as C symbol,
765 // define __start and __stop symbols for the section. This is a GNU
769 Layout::define_section_symbols(Symbol_table* symtab)
771 for (Section_list::const_iterator p = this->section_list_.begin();
772 p != this->section_list_.end();
775 const char* const name = (*p)->name();
776 if (name[strspn(name,
778 "ABCDEFGHIJKLMNOPWRSTUVWXYZ"
779 "abcdefghijklmnopqrstuvwxyz"
783 const std::string name_string(name);
784 const std::string start_name("__start_" + name_string);
785 const std::string stop_name("__stop_" + name_string);
787 symtab->define_in_output_data(start_name.c_str(),
796 false, // offset_is_from_end
797 true); // only_if_ref
799 symtab->define_in_output_data(stop_name.c_str(),
808 true, // offset_is_from_end
809 true); // only_if_ref
814 // Define symbols for group signatures.
817 Layout::define_group_signatures(Symbol_table* symtab)
819 for (Group_signatures::iterator p = this->group_signatures_.begin();
820 p != this->group_signatures_.end();
823 Symbol* sym = symtab->lookup(p->signature, NULL);
825 p->section->set_info_symndx(sym);
828 // Force the name of the group section to the group
829 // signature, and use the group's section symbol as the
831 if (strcmp(p->section->name(), p->signature) != 0)
833 const char* name = this->namepool_.add(p->signature,
835 p->section->set_name(name);
837 p->section->set_needs_symtab_index();
838 p->section->set_info_section_symndx(p->section);
842 this->group_signatures_.clear();
845 // Find the first read-only PT_LOAD segment, creating one if
849 Layout::find_first_load_seg()
851 for (Segment_list::const_iterator p = this->segment_list_.begin();
852 p != this->segment_list_.end();
855 if ((*p)->type() == elfcpp::PT_LOAD
856 && ((*p)->flags() & elfcpp::PF_R) != 0
857 && ((*p)->flags() & elfcpp::PF_W) == 0)
861 gold_assert(!this->script_options_->saw_phdrs_clause());
863 Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
868 // Finalize the layout. When this is called, we have created all the
869 // output sections and all the output segments which are based on
870 // input sections. We have several things to do, and we have to do
871 // them in the right order, so that we get the right results correctly
874 // 1) Finalize the list of output segments and create the segment
877 // 2) Finalize the dynamic symbol table and associated sections.
879 // 3) Determine the final file offset of all the output segments.
881 // 4) Determine the final file offset of all the SHF_ALLOC output
884 // 5) Create the symbol table sections and the section name table
887 // 6) Finalize the symbol table: set symbol values to their final
888 // value and make a final determination of which symbols are going
889 // into the output symbol table.
891 // 7) Create the section table header.
893 // 8) Determine the final file offset of all the output sections which
894 // are not SHF_ALLOC, including the section table header.
896 // 9) Finalize the ELF file header.
898 // This function returns the size of the output file.
901 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
904 Target* const target = parameters->target();
906 target->finalize_sections(this);
908 this->count_local_symbols(task, input_objects);
910 this->create_gold_note();
911 this->create_executable_stack_info(target);
913 Output_segment* phdr_seg = NULL;
914 if (!parameters->output_is_object() && !parameters->doing_static_link())
916 // There was a dynamic object in the link. We need to create
917 // some information for the dynamic linker.
919 // Create the PT_PHDR segment which will hold the program
921 if (!this->script_options_->saw_phdrs_clause())
922 phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
924 // Create the dynamic symbol table, including the hash table.
925 Output_section* dynstr;
926 std::vector<Symbol*> dynamic_symbols;
927 unsigned int local_dynamic_count;
928 Versions versions(this->options_, &this->dynpool_);
929 this->create_dynamic_symtab(input_objects, symtab, &dynstr,
930 &local_dynamic_count, &dynamic_symbols,
933 // Create the .interp section to hold the name of the
934 // interpreter, and put it in a PT_INTERP segment.
935 if (!parameters->output_is_shared())
936 this->create_interp(target);
938 // Finish the .dynamic section to hold the dynamic data, and put
939 // it in a PT_DYNAMIC segment.
940 this->finish_dynamic_section(input_objects, symtab);
942 // We should have added everything we need to the dynamic string
944 this->dynpool_.set_string_offsets();
946 // Create the version sections. We can't do this until the
947 // dynamic string table is complete.
948 this->create_version_sections(&versions, symtab, local_dynamic_count,
949 dynamic_symbols, dynstr);
952 // If there is a SECTIONS clause, put all the input sections into
953 // the required order.
954 Output_segment* load_seg;
955 if (this->script_options_->saw_sections_clause())
956 load_seg = this->set_section_addresses_from_script(symtab);
957 else if (parameters->output_is_object())
960 load_seg = this->find_first_load_seg();
962 if (this->options_.output_format() != General_options::OBJECT_FORMAT_ELF)
965 gold_assert(phdr_seg == NULL || load_seg != NULL);
967 // Lay out the segment headers.
968 Output_segment_headers* segment_headers;
969 if (parameters->output_is_object())
970 segment_headers = NULL;
973 segment_headers = new Output_segment_headers(this->segment_list_);
974 if (load_seg != NULL)
975 load_seg->add_initial_output_data(segment_headers);
976 if (phdr_seg != NULL)
977 phdr_seg->add_initial_output_data(segment_headers);
980 // Lay out the file header.
981 Output_file_header* file_header;
982 file_header = new Output_file_header(target, symtab, segment_headers,
983 this->script_options_->entry());
984 if (load_seg != NULL)
985 load_seg->add_initial_output_data(file_header);
987 this->special_output_list_.push_back(file_header);
988 if (segment_headers != NULL)
989 this->special_output_list_.push_back(segment_headers);
991 if (this->script_options_->saw_phdrs_clause()
992 && !parameters->output_is_object())
994 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
995 // clause in a linker script.
996 Script_sections* ss = this->script_options_->script_sections();
997 ss->put_headers_in_phdrs(file_header, segment_headers);
1000 // We set the output section indexes in set_segment_offsets and
1001 // set_section_indexes.
1002 unsigned int shndx = 1;
1004 // Set the file offsets of all the segments, and all the sections
1007 if (!parameters->output_is_object())
1008 off = this->set_segment_offsets(target, load_seg, &shndx);
1010 off = this->set_relocatable_section_offsets(file_header, &shndx);
1012 // Set the file offsets of all the non-data sections we've seen so
1013 // far which don't have to wait for the input sections. We need
1014 // this in order to finalize local symbols in non-allocated
1016 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1018 // Create the symbol table sections.
1019 this->create_symtab_sections(input_objects, symtab, &off);
1020 if (!parameters->doing_static_link())
1021 this->assign_local_dynsym_offsets(input_objects);
1023 // Process any symbol assignments from a linker script. This must
1024 // be called after the symbol table has been finalized.
1025 this->script_options_->finalize_symbols(symtab, this);
1027 // Create the .shstrtab section.
1028 Output_section* shstrtab_section = this->create_shstrtab();
1030 // Set the file offsets of the rest of the non-data sections which
1031 // don't have to wait for the input sections.
1032 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
1034 // Now that all sections have been created, set the section indexes.
1035 shndx = this->set_section_indexes(shndx);
1037 // Create the section table header.
1038 this->create_shdrs(&off);
1040 // If there are no sections which require postprocessing, we can
1041 // handle the section names now, and avoid a resize later.
1042 if (!this->any_postprocessing_sections_)
1043 off = this->set_section_offsets(off,
1044 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
1046 file_header->set_section_info(this->section_headers_, shstrtab_section);
1048 // Now we know exactly where everything goes in the output file
1049 // (except for non-allocated sections which require postprocessing).
1050 Output_data::layout_complete();
1052 this->output_file_size_ = off;
1057 // Create a .note section for an executable or shared library. This
1058 // records the version of gold used to create the binary.
1061 Layout::create_gold_note()
1063 if (parameters->output_is_object())
1066 // Authorities all agree that the values in a .note field should
1067 // be aligned on 4-byte boundaries for 32-bit binaries. However,
1068 // they differ on what the alignment is for 64-bit binaries.
1069 // The GABI says unambiguously they take 8-byte alignment:
1070 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
1071 // Other documentation says alignment should always be 4 bytes:
1072 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
1073 // GNU ld and GNU readelf both support the latter (at least as of
1074 // version 2.16.91), and glibc always generates the latter for
1075 // .note.ABI-tag (as of version 1.6), so that's the one we go with
1077 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
1078 const int size = parameters->get_size();
1080 const int size = 32;
1083 // The contents of the .note section.
1084 const char* name = "GNU";
1085 std::string desc(std::string("gold ") + gold::get_version_string());
1086 size_t namesz = strlen(name) + 1;
1087 size_t aligned_namesz = align_address(namesz, size / 8);
1088 size_t descsz = desc.length() + 1;
1089 size_t aligned_descsz = align_address(descsz, size / 8);
1090 const int note_type = 4;
1092 size_t notesz = 3 * (size / 8) + aligned_namesz + aligned_descsz;
1094 unsigned char buffer[128];
1095 gold_assert(sizeof buffer >= notesz);
1096 memset(buffer, 0, notesz);
1098 bool is_big_endian = parameters->is_big_endian();
1104 elfcpp::Swap<32, false>::writeval(buffer, namesz);
1105 elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
1106 elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
1110 elfcpp::Swap<32, true>::writeval(buffer, namesz);
1111 elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
1112 elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
1115 else if (size == 64)
1119 elfcpp::Swap<64, false>::writeval(buffer, namesz);
1120 elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
1121 elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
1125 elfcpp::Swap<64, true>::writeval(buffer, namesz);
1126 elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
1127 elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
1133 memcpy(buffer + 3 * (size / 8), name, namesz);
1134 memcpy(buffer + 3 * (size / 8) + aligned_namesz, desc.data(), descsz);
1136 const char* note_name = this->namepool_.add(".note", false, NULL);
1137 Output_section* os = this->make_output_section(note_name,
1140 Output_section_data* posd = new Output_data_const(buffer, notesz,
1142 os->add_output_section_data(posd);
1145 // Record whether the stack should be executable. This can be set
1146 // from the command line using the -z execstack or -z noexecstack
1147 // options. Otherwise, if any input file has a .note.GNU-stack
1148 // section with the SHF_EXECINSTR flag set, the stack should be
1149 // executable. Otherwise, if at least one input file a
1150 // .note.GNU-stack section, and some input file has no .note.GNU-stack
1151 // section, we use the target default for whether the stack should be
1152 // executable. Otherwise, we don't generate a stack note. When
1153 // generating a object file, we create a .note.GNU-stack section with
1154 // the appropriate marking. When generating an executable or shared
1155 // library, we create a PT_GNU_STACK segment.
1158 Layout::create_executable_stack_info(const Target* target)
1160 bool is_stack_executable;
1161 if (this->options_.is_execstack_set())
1162 is_stack_executable = this->options_.is_stack_executable();
1163 else if (!this->input_with_gnu_stack_note_)
1167 if (this->input_requires_executable_stack_)
1168 is_stack_executable = true;
1169 else if (this->input_without_gnu_stack_note_)
1170 is_stack_executable = target->is_default_stack_executable();
1172 is_stack_executable = false;
1175 if (parameters->output_is_object())
1177 const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
1178 elfcpp::Elf_Xword flags = 0;
1179 if (is_stack_executable)
1180 flags |= elfcpp::SHF_EXECINSTR;
1181 this->make_output_section(name, elfcpp::SHT_PROGBITS, flags);
1185 if (this->script_options_->saw_phdrs_clause())
1187 int flags = elfcpp::PF_R | elfcpp::PF_W;
1188 if (is_stack_executable)
1189 flags |= elfcpp::PF_X;
1190 this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
1194 // Return whether SEG1 should be before SEG2 in the output file. This
1195 // is based entirely on the segment type and flags. When this is
1196 // called the segment addresses has normally not yet been set.
1199 Layout::segment_precedes(const Output_segment* seg1,
1200 const Output_segment* seg2)
1202 elfcpp::Elf_Word type1 = seg1->type();
1203 elfcpp::Elf_Word type2 = seg2->type();
1205 // The single PT_PHDR segment is required to precede any loadable
1206 // segment. We simply make it always first.
1207 if (type1 == elfcpp::PT_PHDR)
1209 gold_assert(type2 != elfcpp::PT_PHDR);
1212 if (type2 == elfcpp::PT_PHDR)
1215 // The single PT_INTERP segment is required to precede any loadable
1216 // segment. We simply make it always second.
1217 if (type1 == elfcpp::PT_INTERP)
1219 gold_assert(type2 != elfcpp::PT_INTERP);
1222 if (type2 == elfcpp::PT_INTERP)
1225 // We then put PT_LOAD segments before any other segments.
1226 if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
1228 if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
1231 // We put the PT_TLS segment last, because that is where the dynamic
1232 // linker expects to find it (this is just for efficiency; other
1233 // positions would also work correctly).
1234 if (type1 == elfcpp::PT_TLS && type2 != elfcpp::PT_TLS)
1236 if (type2 == elfcpp::PT_TLS && type1 != elfcpp::PT_TLS)
1239 const elfcpp::Elf_Word flags1 = seg1->flags();
1240 const elfcpp::Elf_Word flags2 = seg2->flags();
1242 // The order of non-PT_LOAD segments is unimportant. We simply sort
1243 // by the numeric segment type and flags values. There should not
1244 // be more than one segment with the same type and flags.
1245 if (type1 != elfcpp::PT_LOAD)
1248 return type1 < type2;
1249 gold_assert(flags1 != flags2);
1250 return flags1 < flags2;
1253 // If the addresses are set already, sort by load address.
1254 if (seg1->are_addresses_set())
1256 if (!seg2->are_addresses_set())
1259 unsigned int section_count1 = seg1->output_section_count();
1260 unsigned int section_count2 = seg2->output_section_count();
1261 if (section_count1 == 0 && section_count2 > 0)
1263 if (section_count1 > 0 && section_count2 == 0)
1266 uint64_t paddr1 = seg1->first_section_load_address();
1267 uint64_t paddr2 = seg2->first_section_load_address();
1268 if (paddr1 != paddr2)
1269 return paddr1 < paddr2;
1271 else if (seg2->are_addresses_set())
1274 // We sort PT_LOAD segments based on the flags. Readonly segments
1275 // come before writable segments. Then writable segments with data
1276 // come before writable segments without data. Then executable
1277 // segments come before non-executable segments. Then the unlikely
1278 // case of a non-readable segment comes before the normal case of a
1279 // readable segment. If there are multiple segments with the same
1280 // type and flags, we require that the address be set, and we sort
1281 // by virtual address and then physical address.
1282 if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
1283 return (flags1 & elfcpp::PF_W) == 0;
1284 if ((flags1 & elfcpp::PF_W) != 0
1285 && seg1->has_any_data_sections() != seg2->has_any_data_sections())
1286 return seg1->has_any_data_sections();
1287 if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
1288 return (flags1 & elfcpp::PF_X) != 0;
1289 if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
1290 return (flags1 & elfcpp::PF_R) == 0;
1292 // We shouldn't get here--we shouldn't create segments which we
1293 // can't distinguish.
1297 // Set the file offsets of all the segments, and all the sections they
1298 // contain. They have all been created. LOAD_SEG must be be laid out
1299 // first. Return the offset of the data to follow.
1302 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
1303 unsigned int *pshndx)
1305 // Sort them into the final order.
1306 std::sort(this->segment_list_.begin(), this->segment_list_.end(),
1307 Layout::Compare_segments());
1309 // Find the PT_LOAD segments, and set their addresses and offsets
1310 // and their section's addresses and offsets.
1312 if (this->options_.user_set_text_segment_address())
1313 addr = this->options_.text_segment_address();
1314 else if (parameters->output_is_shared())
1317 addr = target->default_text_segment_address();
1320 // If LOAD_SEG is NULL, then the file header and segment headers
1321 // will not be loadable. But they still need to be at offset 0 in
1322 // the file. Set their offsets now.
1323 if (load_seg == NULL)
1325 for (Data_list::iterator p = this->special_output_list_.begin();
1326 p != this->special_output_list_.end();
1329 off = align_address(off, (*p)->addralign());
1330 (*p)->set_address_and_file_offset(0, off);
1331 off += (*p)->data_size();
1335 bool was_readonly = false;
1336 for (Segment_list::iterator p = this->segment_list_.begin();
1337 p != this->segment_list_.end();
1340 if ((*p)->type() == elfcpp::PT_LOAD)
1342 if (load_seg != NULL && load_seg != *p)
1346 bool are_addresses_set = (*p)->are_addresses_set();
1347 if (are_addresses_set)
1349 // When it comes to setting file offsets, we care about
1350 // the physical address.
1351 addr = (*p)->paddr();
1353 else if (this->options_.user_set_data_segment_address()
1354 && ((*p)->flags() & elfcpp::PF_W) != 0
1355 && (!this->options_.user_set_bss_segment_address()
1356 || (*p)->has_any_data_sections()))
1358 addr = this->options_.data_segment_address();
1359 are_addresses_set = true;
1361 else if (this->options_.user_set_bss_segment_address()
1362 && ((*p)->flags() & elfcpp::PF_W) != 0
1363 && !(*p)->has_any_data_sections())
1365 addr = this->options_.bss_segment_address();
1366 are_addresses_set = true;
1369 uint64_t orig_addr = addr;
1370 uint64_t orig_off = off;
1372 uint64_t aligned_addr = 0;
1373 uint64_t abi_pagesize = target->abi_pagesize();
1375 // FIXME: This should depend on the -n and -N options.
1376 (*p)->set_minimum_p_align(target->common_pagesize());
1378 if (are_addresses_set)
1380 // Adjust the file offset to the same address modulo the
1382 uint64_t unsigned_off = off;
1383 uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
1384 | (addr & (abi_pagesize - 1)));
1385 if (aligned_off < unsigned_off)
1386 aligned_off += abi_pagesize;
1391 // If the last segment was readonly, and this one is
1392 // not, then skip the address forward one page,
1393 // maintaining the same position within the page. This
1394 // lets us store both segments overlapping on a single
1395 // page in the file, but the loader will put them on
1396 // different pages in memory.
1398 addr = align_address(addr, (*p)->maximum_alignment());
1399 aligned_addr = addr;
1401 if (was_readonly && ((*p)->flags() & elfcpp::PF_W) != 0)
1403 if ((addr & (abi_pagesize - 1)) != 0)
1404 addr = addr + abi_pagesize;
1407 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
1410 unsigned int shndx_hold = *pshndx;
1411 uint64_t new_addr = (*p)->set_section_addresses(false, addr, &off,
1414 // Now that we know the size of this segment, we may be able
1415 // to save a page in memory, at the cost of wasting some
1416 // file space, by instead aligning to the start of a new
1417 // page. Here we use the real machine page size rather than
1418 // the ABI mandated page size.
1420 if (!are_addresses_set && aligned_addr != addr)
1422 uint64_t common_pagesize = target->common_pagesize();
1423 uint64_t first_off = (common_pagesize
1425 & (common_pagesize - 1)));
1426 uint64_t last_off = new_addr & (common_pagesize - 1);
1429 && ((aligned_addr & ~ (common_pagesize - 1))
1430 != (new_addr & ~ (common_pagesize - 1)))
1431 && first_off + last_off <= common_pagesize)
1433 *pshndx = shndx_hold;
1434 addr = align_address(aligned_addr, common_pagesize);
1435 addr = align_address(addr, (*p)->maximum_alignment());
1436 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
1437 new_addr = (*p)->set_section_addresses(true, addr, &off,
1444 if (((*p)->flags() & elfcpp::PF_W) == 0)
1445 was_readonly = true;
1449 // Handle the non-PT_LOAD segments, setting their offsets from their
1450 // section's offsets.
1451 for (Segment_list::iterator p = this->segment_list_.begin();
1452 p != this->segment_list_.end();
1455 if ((*p)->type() != elfcpp::PT_LOAD)
1459 // Set the TLS offsets for each section in the PT_TLS segment.
1460 if (this->tls_segment_ != NULL)
1461 this->tls_segment_->set_tls_offsets();
1466 // Set the offsets of all the allocated sections when doing a
1467 // relocatable link. This does the same jobs as set_segment_offsets,
1468 // only for a relocatable link.
1471 Layout::set_relocatable_section_offsets(Output_data* file_header,
1472 unsigned int *pshndx)
1476 file_header->set_address_and_file_offset(0, 0);
1477 off += file_header->data_size();
1479 for (Section_list::iterator p = this->section_list_.begin();
1480 p != this->section_list_.end();
1483 // We skip unallocated sections here, except that group sections
1484 // have to come first.
1485 if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
1486 && (*p)->type() != elfcpp::SHT_GROUP)
1489 off = align_address(off, (*p)->addralign());
1491 // The linker script might have set the address.
1492 if (!(*p)->is_address_valid())
1493 (*p)->set_address(0);
1494 (*p)->set_file_offset(off);
1495 (*p)->finalize_data_size();
1496 off += (*p)->data_size();
1498 (*p)->set_out_shndx(*pshndx);
1505 // Set the file offset of all the sections not associated with a
1509 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
1511 for (Section_list::iterator p = this->unattached_section_list_.begin();
1512 p != this->unattached_section_list_.end();
1515 // The symtab section is handled in create_symtab_sections.
1516 if (*p == this->symtab_section_)
1519 // If we've already set the data size, don't set it again.
1520 if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
1523 if (pass == BEFORE_INPUT_SECTIONS_PASS
1524 && (*p)->requires_postprocessing())
1526 (*p)->create_postprocessing_buffer();
1527 this->any_postprocessing_sections_ = true;
1530 if (pass == BEFORE_INPUT_SECTIONS_PASS
1531 && (*p)->after_input_sections())
1533 else if (pass == POSTPROCESSING_SECTIONS_PASS
1534 && (!(*p)->after_input_sections()
1535 || (*p)->type() == elfcpp::SHT_STRTAB))
1537 else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
1538 && (!(*p)->after_input_sections()
1539 || (*p)->type() != elfcpp::SHT_STRTAB))
1542 off = align_address(off, (*p)->addralign());
1543 (*p)->set_file_offset(off);
1544 (*p)->finalize_data_size();
1545 off += (*p)->data_size();
1547 // At this point the name must be set.
1548 if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
1549 this->namepool_.add((*p)->name(), false, NULL);
1554 // Set the section indexes of all the sections not associated with a
1558 Layout::set_section_indexes(unsigned int shndx)
1560 const bool output_is_object = parameters->output_is_object();
1561 for (Section_list::iterator p = this->unattached_section_list_.begin();
1562 p != this->unattached_section_list_.end();
1565 // In a relocatable link, we already did group sections.
1566 if (output_is_object
1567 && (*p)->type() == elfcpp::SHT_GROUP)
1570 (*p)->set_out_shndx(shndx);
1576 // Set the section addresses according to the linker script. This is
1577 // only called when we see a SECTIONS clause. This returns the
1578 // program segment which should hold the file header and segment
1579 // headers, if any. It will return NULL if they should not be in a
1583 Layout::set_section_addresses_from_script(Symbol_table* symtab)
1585 Script_sections* ss = this->script_options_->script_sections();
1586 gold_assert(ss->saw_sections_clause());
1588 // Place each orphaned output section in the script.
1589 for (Section_list::iterator p = this->section_list_.begin();
1590 p != this->section_list_.end();
1593 if (!(*p)->found_in_sections_clause())
1594 ss->place_orphan(*p);
1597 return this->script_options_->set_section_addresses(symtab, this);
1600 // Count the local symbols in the regular symbol table and the dynamic
1601 // symbol table, and build the respective string pools.
1604 Layout::count_local_symbols(const Task* task,
1605 const Input_objects* input_objects)
1607 // First, figure out an upper bound on the number of symbols we'll
1608 // be inserting into each pool. This helps us create the pools with
1609 // the right size, to avoid unnecessary hashtable resizing.
1610 unsigned int symbol_count = 0;
1611 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1612 p != input_objects->relobj_end();
1614 symbol_count += (*p)->local_symbol_count();
1616 // Go from "upper bound" to "estimate." We overcount for two
1617 // reasons: we double-count symbols that occur in more than one
1618 // object file, and we count symbols that are dropped from the
1619 // output. Add it all together and assume we overcount by 100%.
1622 // We assume all symbols will go into both the sympool and dynpool.
1623 this->sympool_.reserve(symbol_count);
1624 this->dynpool_.reserve(symbol_count);
1626 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1627 p != input_objects->relobj_end();
1630 Task_lock_obj<Object> tlo(task, *p);
1631 (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
1635 // Create the symbol table sections. Here we also set the final
1636 // values of the symbols. At this point all the loadable sections are
1640 Layout::create_symtab_sections(const Input_objects* input_objects,
1641 Symbol_table* symtab,
1646 if (parameters->get_size() == 32)
1648 symsize = elfcpp::Elf_sizes<32>::sym_size;
1651 else if (parameters->get_size() == 64)
1653 symsize = elfcpp::Elf_sizes<64>::sym_size;
1660 off = align_address(off, align);
1661 off_t startoff = off;
1663 // Save space for the dummy symbol at the start of the section. We
1664 // never bother to write this out--it will just be left as zero.
1666 unsigned int local_symbol_index = 1;
1668 // Add STT_SECTION symbols for each Output section which needs one.
1669 for (Section_list::iterator p = this->section_list_.begin();
1670 p != this->section_list_.end();
1673 if (!(*p)->needs_symtab_index())
1674 (*p)->set_symtab_index(-1U);
1677 (*p)->set_symtab_index(local_symbol_index);
1678 ++local_symbol_index;
1683 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1684 p != input_objects->relobj_end();
1687 unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
1689 off += (index - local_symbol_index) * symsize;
1690 local_symbol_index = index;
1693 unsigned int local_symcount = local_symbol_index;
1694 gold_assert(local_symcount * symsize == off - startoff);
1697 size_t dyn_global_index;
1699 if (this->dynsym_section_ == NULL)
1702 dyn_global_index = 0;
1707 dyn_global_index = this->dynsym_section_->info();
1708 off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
1709 dynoff = this->dynsym_section_->offset() + locsize;
1710 dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
1711 gold_assert(static_cast<off_t>(dyncount * symsize)
1712 == this->dynsym_section_->data_size() - locsize);
1715 off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
1716 &this->sympool_, &local_symcount);
1718 if (!parameters->strip_all())
1720 this->sympool_.set_string_offsets();
1722 const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
1723 Output_section* osymtab = this->make_output_section(symtab_name,
1726 this->symtab_section_ = osymtab;
1728 Output_section_data* pos = new Output_data_fixed_space(off - startoff,
1730 osymtab->add_output_section_data(pos);
1732 const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
1733 Output_section* ostrtab = this->make_output_section(strtab_name,
1737 Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
1738 ostrtab->add_output_section_data(pstr);
1740 osymtab->set_file_offset(startoff);
1741 osymtab->finalize_data_size();
1742 osymtab->set_link_section(ostrtab);
1743 osymtab->set_info(local_symcount);
1744 osymtab->set_entsize(symsize);
1750 // Create the .shstrtab section, which holds the names of the
1751 // sections. At the time this is called, we have created all the
1752 // output sections except .shstrtab itself.
1755 Layout::create_shstrtab()
1757 // FIXME: We don't need to create a .shstrtab section if we are
1758 // stripping everything.
1760 const char* name = this->namepool_.add(".shstrtab", false, NULL);
1762 Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0);
1764 // We can't write out this section until we've set all the section
1765 // names, and we don't set the names of compressed output sections
1766 // until relocations are complete.
1767 os->set_after_input_sections();
1769 Output_section_data* posd = new Output_data_strtab(&this->namepool_);
1770 os->add_output_section_data(posd);
1775 // Create the section headers. SIZE is 32 or 64. OFF is the file
1779 Layout::create_shdrs(off_t* poff)
1781 Output_section_headers* oshdrs;
1782 oshdrs = new Output_section_headers(this,
1783 &this->segment_list_,
1784 &this->section_list_,
1785 &this->unattached_section_list_,
1787 off_t off = align_address(*poff, oshdrs->addralign());
1788 oshdrs->set_address_and_file_offset(0, off);
1789 off += oshdrs->data_size();
1791 this->section_headers_ = oshdrs;
1794 // Create the dynamic symbol table.
1797 Layout::create_dynamic_symtab(const Input_objects* input_objects,
1798 Symbol_table* symtab,
1799 Output_section **pdynstr,
1800 unsigned int* plocal_dynamic_count,
1801 std::vector<Symbol*>* pdynamic_symbols,
1802 Versions* pversions)
1804 // Count all the symbols in the dynamic symbol table, and set the
1805 // dynamic symbol indexes.
1807 // Skip symbol 0, which is always all zeroes.
1808 unsigned int index = 1;
1810 // Add STT_SECTION symbols for each Output section which needs one.
1811 for (Section_list::iterator p = this->section_list_.begin();
1812 p != this->section_list_.end();
1815 if (!(*p)->needs_dynsym_index())
1816 (*p)->set_dynsym_index(-1U);
1819 (*p)->set_dynsym_index(index);
1824 // Count the local symbols that need to go in the dynamic symbol table,
1825 // and set the dynamic symbol indexes.
1826 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1827 p != input_objects->relobj_end();
1830 unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
1834 unsigned int local_symcount = index;
1835 *plocal_dynamic_count = local_symcount;
1837 // FIXME: We have to tell set_dynsym_indexes whether the
1838 // -E/--export-dynamic option was used.
1839 index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
1840 &this->dynpool_, pversions);
1844 const int size = parameters->get_size();
1847 symsize = elfcpp::Elf_sizes<32>::sym_size;
1850 else if (size == 64)
1852 symsize = elfcpp::Elf_sizes<64>::sym_size;
1858 // Create the dynamic symbol table section.
1860 Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
1865 Output_section_data* odata = new Output_data_fixed_space(index * symsize,
1867 dynsym->add_output_section_data(odata);
1869 dynsym->set_info(local_symcount);
1870 dynsym->set_entsize(symsize);
1871 dynsym->set_addralign(align);
1873 this->dynsym_section_ = dynsym;
1875 Output_data_dynamic* const odyn = this->dynamic_data_;
1876 odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
1877 odyn->add_constant(elfcpp::DT_SYMENT, symsize);
1879 // Create the dynamic string table section.
1881 Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
1886 Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
1887 dynstr->add_output_section_data(strdata);
1889 dynsym->set_link_section(dynstr);
1890 this->dynamic_section_->set_link_section(dynstr);
1892 odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
1893 odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
1897 // Create the hash tables.
1899 // FIXME: We need an option to create a GNU hash table.
1901 unsigned char* phash;
1902 unsigned int hashlen;
1903 Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
1906 Output_section* hashsec = this->choose_output_section(NULL, ".hash",
1911 Output_section_data* hashdata = new Output_data_const_buffer(phash,
1914 hashsec->add_output_section_data(hashdata);
1916 hashsec->set_link_section(dynsym);
1917 hashsec->set_entsize(4);
1919 odyn->add_section_address(elfcpp::DT_HASH, hashsec);
1922 // Assign offsets to each local portion of the dynamic symbol table.
1925 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
1927 Output_section* dynsym = this->dynsym_section_;
1928 gold_assert(dynsym != NULL);
1930 off_t off = dynsym->offset();
1932 // Skip the dummy symbol at the start of the section.
1933 off += dynsym->entsize();
1935 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
1936 p != input_objects->relobj_end();
1939 unsigned int count = (*p)->set_local_dynsym_offset(off);
1940 off += count * dynsym->entsize();
1944 // Create the version sections.
1947 Layout::create_version_sections(const Versions* versions,
1948 const Symbol_table* symtab,
1949 unsigned int local_symcount,
1950 const std::vector<Symbol*>& dynamic_symbols,
1951 const Output_section* dynstr)
1953 if (!versions->any_defs() && !versions->any_needs())
1956 if (parameters->get_size() == 32)
1958 if (parameters->is_big_endian())
1960 #ifdef HAVE_TARGET_32_BIG
1961 this->sized_create_version_sections
1962 SELECT_SIZE_ENDIAN_NAME(32, true)(
1963 versions, symtab, local_symcount, dynamic_symbols, dynstr
1964 SELECT_SIZE_ENDIAN(32, true));
1971 #ifdef HAVE_TARGET_32_LITTLE
1972 this->sized_create_version_sections
1973 SELECT_SIZE_ENDIAN_NAME(32, false)(
1974 versions, symtab, local_symcount, dynamic_symbols, dynstr
1975 SELECT_SIZE_ENDIAN(32, false));
1981 else if (parameters->get_size() == 64)
1983 if (parameters->is_big_endian())
1985 #ifdef HAVE_TARGET_64_BIG
1986 this->sized_create_version_sections
1987 SELECT_SIZE_ENDIAN_NAME(64, true)(
1988 versions, symtab, local_symcount, dynamic_symbols, dynstr
1989 SELECT_SIZE_ENDIAN(64, true));
1996 #ifdef HAVE_TARGET_64_LITTLE
1997 this->sized_create_version_sections
1998 SELECT_SIZE_ENDIAN_NAME(64, false)(
1999 versions, symtab, local_symcount, dynamic_symbols, dynstr
2000 SELECT_SIZE_ENDIAN(64, false));
2010 // Create the version sections, sized version.
2012 template<int size, bool big_endian>
2014 Layout::sized_create_version_sections(
2015 const Versions* versions,
2016 const Symbol_table* symtab,
2017 unsigned int local_symcount,
2018 const std::vector<Symbol*>& dynamic_symbols,
2019 const Output_section* dynstr
2022 Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
2023 elfcpp::SHT_GNU_versym,
2027 unsigned char* vbuf;
2029 versions->symbol_section_contents SELECT_SIZE_ENDIAN_NAME(size, big_endian)(
2030 symtab, &this->dynpool_, local_symcount, dynamic_symbols, &vbuf, &vsize
2031 SELECT_SIZE_ENDIAN(size, big_endian));
2033 Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2);
2035 vsec->add_output_section_data(vdata);
2036 vsec->set_entsize(2);
2037 vsec->set_link_section(this->dynsym_section_);
2039 Output_data_dynamic* const odyn = this->dynamic_data_;
2040 odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
2042 if (versions->any_defs())
2044 Output_section* vdsec;
2045 vdsec= this->choose_output_section(NULL, ".gnu.version_d",
2046 elfcpp::SHT_GNU_verdef,
2050 unsigned char* vdbuf;
2051 unsigned int vdsize;
2052 unsigned int vdentries;
2053 versions->def_section_contents SELECT_SIZE_ENDIAN_NAME(size, big_endian)(
2054 &this->dynpool_, &vdbuf, &vdsize, &vdentries
2055 SELECT_SIZE_ENDIAN(size, big_endian));
2057 Output_section_data* vddata = new Output_data_const_buffer(vdbuf,
2061 vdsec->add_output_section_data(vddata);
2062 vdsec->set_link_section(dynstr);
2063 vdsec->set_info(vdentries);
2065 odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
2066 odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
2069 if (versions->any_needs())
2071 Output_section* vnsec;
2072 vnsec = this->choose_output_section(NULL, ".gnu.version_r",
2073 elfcpp::SHT_GNU_verneed,
2077 unsigned char* vnbuf;
2078 unsigned int vnsize;
2079 unsigned int vnentries;
2080 versions->need_section_contents SELECT_SIZE_ENDIAN_NAME(size, big_endian)
2081 (&this->dynpool_, &vnbuf, &vnsize, &vnentries
2082 SELECT_SIZE_ENDIAN(size, big_endian));
2084 Output_section_data* vndata = new Output_data_const_buffer(vnbuf,
2088 vnsec->add_output_section_data(vndata);
2089 vnsec->set_link_section(dynstr);
2090 vnsec->set_info(vnentries);
2092 odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
2093 odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
2097 // Create the .interp section and PT_INTERP segment.
2100 Layout::create_interp(const Target* target)
2102 const char* interp = this->options_.dynamic_linker();
2105 interp = target->dynamic_linker();
2106 gold_assert(interp != NULL);
2109 size_t len = strlen(interp) + 1;
2111 Output_section_data* odata = new Output_data_const(interp, len, 1);
2113 Output_section* osec = this->choose_output_section(NULL, ".interp",
2114 elfcpp::SHT_PROGBITS,
2117 osec->add_output_section_data(odata);
2119 if (!this->script_options_->saw_phdrs_clause())
2121 Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP,
2123 oseg->add_initial_output_section(osec, elfcpp::PF_R);
2127 // Finish the .dynamic section and PT_DYNAMIC segment.
2130 Layout::finish_dynamic_section(const Input_objects* input_objects,
2131 const Symbol_table* symtab)
2133 if (!this->script_options_->saw_phdrs_clause())
2135 Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
2138 oseg->add_initial_output_section(this->dynamic_section_,
2139 elfcpp::PF_R | elfcpp::PF_W);
2142 Output_data_dynamic* const odyn = this->dynamic_data_;
2144 for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
2145 p != input_objects->dynobj_end();
2148 // FIXME: Handle --as-needed.
2149 odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
2152 if (parameters->output_is_shared())
2154 const char* soname = this->options_.soname();
2156 odyn->add_string(elfcpp::DT_SONAME, soname);
2159 // FIXME: Support --init and --fini.
2160 Symbol* sym = symtab->lookup("_init");
2161 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
2162 odyn->add_symbol(elfcpp::DT_INIT, sym);
2164 sym = symtab->lookup("_fini");
2165 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
2166 odyn->add_symbol(elfcpp::DT_FINI, sym);
2168 // FIXME: Support DT_INIT_ARRAY and DT_FINI_ARRAY.
2170 // Add a DT_RPATH entry if needed.
2171 const General_options::Dir_list& rpath(this->options_.rpath());
2174 std::string rpath_val;
2175 for (General_options::Dir_list::const_iterator p = rpath.begin();
2179 if (rpath_val.empty())
2180 rpath_val = p->name();
2183 // Eliminate duplicates.
2184 General_options::Dir_list::const_iterator q;
2185 for (q = rpath.begin(); q != p; ++q)
2186 if (q->name() == p->name())
2191 rpath_val += p->name();
2196 odyn->add_string(elfcpp::DT_RPATH, rpath_val);
2199 // Look for text segments that have dynamic relocations.
2200 bool have_textrel = false;
2201 if (!this->script_options_->saw_sections_clause())
2203 for (Segment_list::const_iterator p = this->segment_list_.begin();
2204 p != this->segment_list_.end();
2207 if (((*p)->flags() & elfcpp::PF_W) == 0
2208 && (*p)->dynamic_reloc_count() > 0)
2210 have_textrel = true;
2217 // We don't know the section -> segment mapping, so we are
2218 // conservative and just look for readonly sections with
2219 // relocations. If those sections wind up in writable segments,
2220 // then we have created an unnecessary DT_TEXTREL entry.
2221 for (Section_list::const_iterator p = this->section_list_.begin();
2222 p != this->section_list_.end();
2225 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
2226 && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
2227 && ((*p)->dynamic_reloc_count() > 0))
2229 have_textrel = true;
2235 // Add a DT_FLAGS entry. We add it even if no flags are set so that
2236 // post-link tools can easily modify these flags if desired.
2237 unsigned int flags = 0;
2240 // Add a DT_TEXTREL for compatibility with older loaders.
2241 odyn->add_constant(elfcpp::DT_TEXTREL, 0);
2242 flags |= elfcpp::DF_TEXTREL;
2244 if (parameters->output_is_shared() && this->has_static_tls())
2245 flags |= elfcpp::DF_STATIC_TLS;
2246 odyn->add_constant(elfcpp::DT_FLAGS, flags);
2249 // The mapping of .gnu.linkonce section names to real section names.
2251 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
2252 const Layout::Linkonce_mapping Layout::linkonce_mapping[] =
2254 MAPPING_INIT("d.rel.ro", ".data.rel.ro"), // Must be before "d".
2255 MAPPING_INIT("t", ".text"),
2256 MAPPING_INIT("r", ".rodata"),
2257 MAPPING_INIT("d", ".data"),
2258 MAPPING_INIT("b", ".bss"),
2259 MAPPING_INIT("s", ".sdata"),
2260 MAPPING_INIT("sb", ".sbss"),
2261 MAPPING_INIT("s2", ".sdata2"),
2262 MAPPING_INIT("sb2", ".sbss2"),
2263 MAPPING_INIT("wi", ".debug_info"),
2264 MAPPING_INIT("td", ".tdata"),
2265 MAPPING_INIT("tb", ".tbss"),
2266 MAPPING_INIT("lr", ".lrodata"),
2267 MAPPING_INIT("l", ".ldata"),
2268 MAPPING_INIT("lb", ".lbss"),
2272 const int Layout::linkonce_mapping_count =
2273 sizeof(Layout::linkonce_mapping) / sizeof(Layout::linkonce_mapping[0]);
2275 // Return the name of the output section to use for a .gnu.linkonce
2276 // section. This is based on the default ELF linker script of the old
2277 // GNU linker. For example, we map a name like ".gnu.linkonce.t.foo"
2278 // to ".text". Set *PLEN to the length of the name. *PLEN is
2279 // initialized to the length of NAME.
2282 Layout::linkonce_output_name(const char* name, size_t *plen)
2284 const char* s = name + sizeof(".gnu.linkonce") - 1;
2288 const Linkonce_mapping* plm = linkonce_mapping;
2289 for (int i = 0; i < linkonce_mapping_count; ++i, ++plm)
2291 if (strncmp(s, plm->from, plm->fromlen) == 0 && s[plm->fromlen] == '.')
2300 // Choose the output section name to use given an input section name.
2301 // Set *PLEN to the length of the name. *PLEN is initialized to the
2305 Layout::output_section_name(const char* name, size_t* plen)
2307 if (Layout::is_linkonce(name))
2309 // .gnu.linkonce sections are laid out as though they were named
2310 // for the sections are placed into.
2311 return Layout::linkonce_output_name(name, plen);
2314 // gcc 4.3 generates the following sorts of section names when it
2315 // needs a section name specific to a function:
2321 // .data.rel.local.FN
2323 // .data.rel.ro.local.FN
2330 // The GNU linker maps all of those to the part before the .FN,
2331 // except that .data.rel.local.FN is mapped to .data, and
2332 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
2333 // beginning with .data.rel.ro.local are grouped together.
2335 // For an anonymous namespace, the string FN can contain a '.'.
2337 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
2338 // GNU linker maps to .rodata.
2340 // The .data.rel.ro sections enable a security feature triggered by
2341 // the -z relro option. Section which need to be relocated at
2342 // program startup time but which may be readonly after startup are
2343 // grouped into .data.rel.ro. They are then put into a PT_GNU_RELRO
2344 // segment. The dynamic linker will make that segment writable,
2345 // perform relocations, and then make it read-only. FIXME: We do
2346 // not yet implement this optimization.
2348 // It is hard to handle this in a principled way.
2350 // These are the rules we follow:
2352 // If the section name has no initial '.', or no dot other than an
2353 // initial '.', we use the name unchanged (i.e., "mysection" and
2354 // ".text" are unchanged).
2356 // If the name starts with ".data.rel.ro" we use ".data.rel.ro".
2358 // Otherwise, we drop the second '.' and everything that comes after
2359 // it (i.e., ".text.XXX" becomes ".text").
2361 const char* s = name;
2365 const char* sdot = strchr(s, '.');
2369 const char* const data_rel_ro = ".data.rel.ro";
2370 if (strncmp(name, data_rel_ro, strlen(data_rel_ro)) == 0)
2372 *plen = strlen(data_rel_ro);
2376 *plen = sdot - name;
2380 // Record the signature of a comdat section, and return whether to
2381 // include it in the link. If GROUP is true, this is a regular
2382 // section group. If GROUP is false, this is a group signature
2383 // derived from the name of a linkonce section. We want linkonce
2384 // signatures and group signatures to block each other, but we don't
2385 // want a linkonce signature to block another linkonce signature.
2388 Layout::add_comdat(const char* signature, bool group)
2390 std::string sig(signature);
2391 std::pair<Signatures::iterator, bool> ins(
2392 this->signatures_.insert(std::make_pair(sig, group)));
2396 // This is the first time we've seen this signature.
2400 if (ins.first->second)
2402 // We've already seen a real section group with this signature.
2407 // This is a real section group, and we've already seen a
2408 // linkonce section with this signature. Record that we've seen
2409 // a section group, and don't include this section group.
2410 ins.first->second = true;
2415 // We've already seen a linkonce section and this is a linkonce
2416 // section. These don't block each other--this may be the same
2417 // symbol name with different section types.
2422 // Store the allocated sections into the section list.
2425 Layout::get_allocated_sections(Section_list* section_list) const
2427 for (Section_list::const_iterator p = this->section_list_.begin();
2428 p != this->section_list_.end();
2430 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
2431 section_list->push_back(*p);
2434 // Create an output segment.
2437 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
2439 gold_assert(!parameters->output_is_object());
2440 Output_segment* oseg = new Output_segment(type, flags);
2441 this->segment_list_.push_back(oseg);
2445 // Write out the Output_sections. Most won't have anything to write,
2446 // since most of the data will come from input sections which are
2447 // handled elsewhere. But some Output_sections do have Output_data.
2450 Layout::write_output_sections(Output_file* of) const
2452 for (Section_list::const_iterator p = this->section_list_.begin();
2453 p != this->section_list_.end();
2456 if (!(*p)->after_input_sections())
2461 // Write out data not associated with a section or the symbol table.
2464 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
2466 if (!parameters->strip_all())
2468 const Output_section* symtab_section = this->symtab_section_;
2469 for (Section_list::const_iterator p = this->section_list_.begin();
2470 p != this->section_list_.end();
2473 if ((*p)->needs_symtab_index())
2475 gold_assert(symtab_section != NULL);
2476 unsigned int index = (*p)->symtab_index();
2477 gold_assert(index > 0 && index != -1U);
2478 off_t off = (symtab_section->offset()
2479 + index * symtab_section->entsize());
2480 symtab->write_section_symbol(*p, of, off);
2485 const Output_section* dynsym_section = this->dynsym_section_;
2486 for (Section_list::const_iterator p = this->section_list_.begin();
2487 p != this->section_list_.end();
2490 if ((*p)->needs_dynsym_index())
2492 gold_assert(dynsym_section != NULL);
2493 unsigned int index = (*p)->dynsym_index();
2494 gold_assert(index > 0 && index != -1U);
2495 off_t off = (dynsym_section->offset()
2496 + index * dynsym_section->entsize());
2497 symtab->write_section_symbol(*p, of, off);
2501 // Write out the Output_data which are not in an Output_section.
2502 for (Data_list::const_iterator p = this->special_output_list_.begin();
2503 p != this->special_output_list_.end();
2508 // Write out the Output_sections which can only be written after the
2509 // input sections are complete.
2512 Layout::write_sections_after_input_sections(Output_file* of)
2514 // Determine the final section offsets, and thus the final output
2515 // file size. Note we finalize the .shstrab last, to allow the
2516 // after_input_section sections to modify their section-names before
2518 if (this->any_postprocessing_sections_)
2520 off_t off = this->output_file_size_;
2521 off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
2523 // Now that we've finalized the names, we can finalize the shstrab.
2525 this->set_section_offsets(off,
2526 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
2528 if (off > this->output_file_size_)
2531 this->output_file_size_ = off;
2535 for (Section_list::const_iterator p = this->section_list_.begin();
2536 p != this->section_list_.end();
2539 if ((*p)->after_input_sections())
2543 this->section_headers_->write(of);
2546 // Write out a binary file. This is called after the link is
2547 // complete. IN is the temporary output file we used to generate the
2548 // ELF code. We simply walk through the segments, read them from
2549 // their file offset in IN, and write them to their load address in
2550 // the output file. FIXME: with a bit more work, we could support
2551 // S-records and/or Intel hex format here.
2554 Layout::write_binary(Output_file* in) const
2556 gold_assert(this->options_.output_format()
2557 == General_options::OBJECT_FORMAT_BINARY);
2559 // Get the size of the binary file.
2560 uint64_t max_load_address = 0;
2561 for (Segment_list::const_iterator p = this->segment_list_.begin();
2562 p != this->segment_list_.end();
2565 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
2567 uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
2568 if (max_paddr > max_load_address)
2569 max_load_address = max_paddr;
2573 Output_file out(parameters->output_file_name());
2574 out.open(max_load_address);
2576 for (Segment_list::const_iterator p = this->segment_list_.begin();
2577 p != this->segment_list_.end();
2580 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
2582 const unsigned char* vin = in->get_input_view((*p)->offset(),
2584 unsigned char* vout = out.get_output_view((*p)->paddr(),
2586 memcpy(vout, vin, (*p)->filesz());
2587 out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
2588 in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
2595 // Print statistical information to stderr. This is used for --stats.
2598 Layout::print_stats() const
2600 this->namepool_.print_stats("section name pool");
2601 this->sympool_.print_stats("output symbol name pool");
2602 this->dynpool_.print_stats("dynamic name pool");
2604 for (Section_list::const_iterator p = this->section_list_.begin();
2605 p != this->section_list_.end();
2607 (*p)->print_merge_stats();
2610 // Write_sections_task methods.
2612 // We can always run this task.
2615 Write_sections_task::is_runnable()
2620 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
2624 Write_sections_task::locks(Task_locker* tl)
2626 tl->add(this, this->output_sections_blocker_);
2627 tl->add(this, this->final_blocker_);
2630 // Run the task--write out the data.
2633 Write_sections_task::run(Workqueue*)
2635 this->layout_->write_output_sections(this->of_);
2638 // Write_data_task methods.
2640 // We can always run this task.
2643 Write_data_task::is_runnable()
2648 // We need to unlock FINAL_BLOCKER when finished.
2651 Write_data_task::locks(Task_locker* tl)
2653 tl->add(this, this->final_blocker_);
2656 // Run the task--write out the data.
2659 Write_data_task::run(Workqueue*)
2661 this->layout_->write_data(this->symtab_, this->of_);
2664 // Write_symbols_task methods.
2666 // We can always run this task.
2669 Write_symbols_task::is_runnable()
2674 // We need to unlock FINAL_BLOCKER when finished.
2677 Write_symbols_task::locks(Task_locker* tl)
2679 tl->add(this, this->final_blocker_);
2682 // Run the task--write out the symbols.
2685 Write_symbols_task::run(Workqueue*)
2687 this->symtab_->write_globals(this->input_objects_, this->sympool_,
2688 this->dynpool_, this->of_);
2691 // Write_after_input_sections_task methods.
2693 // We can only run this task after the input sections have completed.
2696 Write_after_input_sections_task::is_runnable()
2698 if (this->input_sections_blocker_->is_blocked())
2699 return this->input_sections_blocker_;
2703 // We need to unlock FINAL_BLOCKER when finished.
2706 Write_after_input_sections_task::locks(Task_locker* tl)
2708 tl->add(this, this->final_blocker_);
2714 Write_after_input_sections_task::run(Workqueue*)
2716 this->layout_->write_sections_after_input_sections(this->of_);
2719 // Close_task_runner methods.
2721 // Run the task--close the file.
2724 Close_task_runner::run(Workqueue*, const Task*)
2726 // If we've been asked to create a binary file, we do so here.
2727 if (this->options_->output_format() != General_options::OBJECT_FORMAT_ELF)
2728 this->layout_->write_binary(this->of_);
2733 // Instantiate the templates we need. We could use the configure
2734 // script to restrict this to only the ones for implemented targets.
2736 #ifdef HAVE_TARGET_32_LITTLE
2739 Layout::layout<32, false>(Sized_relobj<32, false>* object, unsigned int shndx,
2741 const elfcpp::Shdr<32, false>& shdr,
2742 unsigned int, unsigned int, off_t*);
2745 #ifdef HAVE_TARGET_32_BIG
2748 Layout::layout<32, true>(Sized_relobj<32, true>* object, unsigned int shndx,
2750 const elfcpp::Shdr<32, true>& shdr,
2751 unsigned int, unsigned int, off_t*);
2754 #ifdef HAVE_TARGET_64_LITTLE
2757 Layout::layout<64, false>(Sized_relobj<64, false>* object, unsigned int shndx,
2759 const elfcpp::Shdr<64, false>& shdr,
2760 unsigned int, unsigned int, off_t*);
2763 #ifdef HAVE_TARGET_64_BIG
2766 Layout::layout<64, true>(Sized_relobj<64, true>* object, unsigned int shndx,
2768 const elfcpp::Shdr<64, true>& shdr,
2769 unsigned int, unsigned int, off_t*);
2772 #ifdef HAVE_TARGET_32_LITTLE
2775 Layout::layout_reloc<32, false>(Sized_relobj<32, false>* object,
2776 unsigned int reloc_shndx,
2777 const elfcpp::Shdr<32, false>& shdr,
2778 Output_section* data_section,
2779 Relocatable_relocs* rr);
2782 #ifdef HAVE_TARGET_32_BIG
2785 Layout::layout_reloc<32, true>(Sized_relobj<32, true>* object,
2786 unsigned int reloc_shndx,
2787 const elfcpp::Shdr<32, true>& shdr,
2788 Output_section* data_section,
2789 Relocatable_relocs* rr);
2792 #ifdef HAVE_TARGET_64_LITTLE
2795 Layout::layout_reloc<64, false>(Sized_relobj<64, false>* object,
2796 unsigned int reloc_shndx,
2797 const elfcpp::Shdr<64, false>& shdr,
2798 Output_section* data_section,
2799 Relocatable_relocs* rr);
2802 #ifdef HAVE_TARGET_64_BIG
2805 Layout::layout_reloc<64, true>(Sized_relobj<64, true>* object,
2806 unsigned int reloc_shndx,
2807 const elfcpp::Shdr<64, true>& shdr,
2808 Output_section* data_section,
2809 Relocatable_relocs* rr);
2812 #ifdef HAVE_TARGET_32_LITTLE
2815 Layout::layout_group<32, false>(Symbol_table* symtab,
2816 Sized_relobj<32, false>* object,
2818 const char* group_section_name,
2819 const char* signature,
2820 const elfcpp::Shdr<32, false>& shdr,
2821 const elfcpp::Elf_Word* contents);
2824 #ifdef HAVE_TARGET_32_BIG
2827 Layout::layout_group<32, true>(Symbol_table* symtab,
2828 Sized_relobj<32, true>* object,
2830 const char* group_section_name,
2831 const char* signature,
2832 const elfcpp::Shdr<32, true>& shdr,
2833 const elfcpp::Elf_Word* contents);
2836 #ifdef HAVE_TARGET_64_LITTLE
2839 Layout::layout_group<64, false>(Symbol_table* symtab,
2840 Sized_relobj<64, false>* object,
2842 const char* group_section_name,
2843 const char* signature,
2844 const elfcpp::Shdr<64, false>& shdr,
2845 const elfcpp::Elf_Word* contents);
2848 #ifdef HAVE_TARGET_64_BIG
2851 Layout::layout_group<64, true>(Symbol_table* symtab,
2852 Sized_relobj<64, true>* object,
2854 const char* group_section_name,
2855 const char* signature,
2856 const elfcpp::Shdr<64, true>& shdr,
2857 const elfcpp::Elf_Word* contents);
2860 #ifdef HAVE_TARGET_32_LITTLE
2863 Layout::layout_eh_frame<32, false>(Sized_relobj<32, false>* object,
2864 const unsigned char* symbols,
2866 const unsigned char* symbol_names,
2867 off_t symbol_names_size,
2869 const elfcpp::Shdr<32, false>& shdr,
2870 unsigned int reloc_shndx,
2871 unsigned int reloc_type,
2875 #ifdef HAVE_TARGET_32_BIG
2878 Layout::layout_eh_frame<32, true>(Sized_relobj<32, true>* object,
2879 const unsigned char* symbols,
2881 const unsigned char* symbol_names,
2882 off_t symbol_names_size,
2884 const elfcpp::Shdr<32, true>& shdr,
2885 unsigned int reloc_shndx,
2886 unsigned int reloc_type,
2890 #ifdef HAVE_TARGET_64_LITTLE
2893 Layout::layout_eh_frame<64, false>(Sized_relobj<64, false>* object,
2894 const unsigned char* symbols,
2896 const unsigned char* symbol_names,
2897 off_t symbol_names_size,
2899 const elfcpp::Shdr<64, false>& shdr,
2900 unsigned int reloc_shndx,
2901 unsigned int reloc_type,
2905 #ifdef HAVE_TARGET_64_BIG
2908 Layout::layout_eh_frame<64, true>(Sized_relobj<64, true>* object,
2909 const unsigned char* symbols,
2911 const unsigned char* symbol_names,
2912 off_t symbol_names_size,
2914 const elfcpp::Shdr<64, true>& shdr,
2915 unsigned int reloc_shndx,
2916 unsigned int reloc_type,
2920 } // End namespace gold.