1 // layout.cc -- lay out output file sections for gold
3 // Copyright (C) 2006-2015 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.
34 #include "libiberty.h"
38 #include "parameters.h"
42 #include "script-sections.h"
47 #include "gdb-index.h"
48 #include "compressed_output.h"
49 #include "reduced_debug_output.h"
52 #include "descriptors.h"
54 #include "incremental.h"
62 // The total number of free lists used.
63 unsigned int Free_list::num_lists = 0;
64 // The total number of free list nodes used.
65 unsigned int Free_list::num_nodes = 0;
66 // The total number of calls to Free_list::remove.
67 unsigned int Free_list::num_removes = 0;
68 // The total number of nodes visited during calls to Free_list::remove.
69 unsigned int Free_list::num_remove_visits = 0;
70 // The total number of calls to Free_list::allocate.
71 unsigned int Free_list::num_allocates = 0;
72 // The total number of nodes visited during calls to Free_list::allocate.
73 unsigned int Free_list::num_allocate_visits = 0;
75 // Initialize the free list. Creates a single free list node that
76 // describes the entire region of length LEN. If EXTEND is true,
77 // allocate() is allowed to extend the region beyond its initial
81 Free_list::init(off_t len, bool extend)
83 this->list_.push_front(Free_list_node(0, len));
84 this->last_remove_ = this->list_.begin();
85 this->extend_ = extend;
87 ++Free_list::num_lists;
88 ++Free_list::num_nodes;
91 // Remove a chunk from the free list. Because we start with a single
92 // node that covers the entire section, and remove chunks from it one
93 // at a time, we do not need to coalesce chunks or handle cases that
94 // span more than one free node. We expect to remove chunks from the
95 // free list in order, and we expect to have only a few chunks of free
96 // space left (corresponding to files that have changed since the last
97 // incremental link), so a simple linear list should provide sufficient
101 Free_list::remove(off_t start, off_t end)
105 gold_assert(start < end);
107 ++Free_list::num_removes;
109 Iterator p = this->last_remove_;
110 if (p->start_ > start)
111 p = this->list_.begin();
113 for (; p != this->list_.end(); ++p)
115 ++Free_list::num_remove_visits;
116 // Find a node that wholly contains the indicated region.
117 if (p->start_ <= start && p->end_ >= end)
119 // Case 1: the indicated region spans the whole node.
120 // Add some fuzz to avoid creating tiny free chunks.
121 if (p->start_ + 3 >= start && p->end_ <= end + 3)
122 p = this->list_.erase(p);
123 // Case 2: remove a chunk from the start of the node.
124 else if (p->start_ + 3 >= start)
126 // Case 3: remove a chunk from the end of the node.
127 else if (p->end_ <= end + 3)
129 // Case 4: remove a chunk from the middle, and split
130 // the node into two.
133 Free_list_node newnode(p->start_, start);
135 this->list_.insert(p, newnode);
136 ++Free_list::num_nodes;
138 this->last_remove_ = p;
143 // Did not find a node containing the given chunk. This could happen
144 // because a small chunk was already removed due to the fuzz.
145 gold_debug(DEBUG_INCREMENTAL,
146 "Free_list::remove(%d,%d) not found",
147 static_cast<int>(start), static_cast<int>(end));
150 // Allocate a chunk of size LEN from the free list. Returns -1ULL
151 // if a sufficiently large chunk of free space is not found.
152 // We use a simple first-fit algorithm.
155 Free_list::allocate(off_t len, uint64_t align, off_t minoff)
157 gold_debug(DEBUG_INCREMENTAL,
158 "Free_list::allocate(%08lx, %d, %08lx)",
159 static_cast<long>(len), static_cast<int>(align),
160 static_cast<long>(minoff));
162 return align_address(minoff, align);
164 ++Free_list::num_allocates;
166 // We usually want to drop free chunks smaller than 4 bytes.
167 // If we need to guarantee a minimum hole size, though, we need
168 // to keep track of all free chunks.
169 const int fuzz = this->min_hole_ > 0 ? 0 : 3;
171 for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
173 ++Free_list::num_allocate_visits;
174 off_t start = p->start_ > minoff ? p->start_ : minoff;
175 start = align_address(start, align);
176 off_t end = start + len;
177 if (end > p->end_ && p->end_ == this->length_ && this->extend_)
182 if (end == p->end_ || (end <= p->end_ - this->min_hole_))
184 if (p->start_ + fuzz >= start && p->end_ <= end + fuzz)
185 this->list_.erase(p);
186 else if (p->start_ + fuzz >= start)
188 else if (p->end_ <= end + fuzz)
192 Free_list_node newnode(p->start_, start);
194 this->list_.insert(p, newnode);
195 ++Free_list::num_nodes;
202 off_t start = align_address(this->length_, align);
203 this->length_ = start + len;
209 // Dump the free list (for debugging).
213 gold_info("Free list:\n start end length\n");
214 for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
215 gold_info(" %08lx %08lx %08lx", static_cast<long>(p->start_),
216 static_cast<long>(p->end_),
217 static_cast<long>(p->end_ - p->start_));
220 // Print the statistics for the free lists.
222 Free_list::print_stats()
224 fprintf(stderr, _("%s: total free lists: %u\n"),
225 program_name, Free_list::num_lists);
226 fprintf(stderr, _("%s: total free list nodes: %u\n"),
227 program_name, Free_list::num_nodes);
228 fprintf(stderr, _("%s: calls to Free_list::remove: %u\n"),
229 program_name, Free_list::num_removes);
230 fprintf(stderr, _("%s: nodes visited: %u\n"),
231 program_name, Free_list::num_remove_visits);
232 fprintf(stderr, _("%s: calls to Free_list::allocate: %u\n"),
233 program_name, Free_list::num_allocates);
234 fprintf(stderr, _("%s: nodes visited: %u\n"),
235 program_name, Free_list::num_allocate_visits);
238 // A Hash_task computes the MD5 checksum of an array of char.
240 class Hash_task : public Task
243 Hash_task(Output_file* of,
247 Task_token* final_blocker)
248 : of_(of), offset_(offset), size_(size), dst_(dst),
249 final_blocker_(final_blocker)
255 const unsigned char* iv =
256 this->of_->get_input_view(this->offset_, this->size_);
257 md5_buffer(reinterpret_cast<const char*>(iv), this->size_, this->dst_);
258 this->of_->free_input_view(this->offset_, this->size_, iv);
265 // Unblock FINAL_BLOCKER_ when done.
267 locks(Task_locker* tl)
268 { tl->add(this, this->final_blocker_); }
272 { return "Hash_task"; }
276 const size_t offset_;
278 unsigned char* const dst_;
279 Task_token* const final_blocker_;
282 // Layout::Relaxation_debug_check methods.
284 // Check that sections and special data are in reset states.
285 // We do not save states for Output_sections and special Output_data.
286 // So we check that they have not assigned any addresses or offsets.
287 // clean_up_after_relaxation simply resets their addresses and offsets.
289 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
290 const Layout::Section_list& sections,
291 const Layout::Data_list& special_outputs,
292 const Layout::Data_list& relax_outputs)
294 for(Layout::Section_list::const_iterator p = sections.begin();
297 gold_assert((*p)->address_and_file_offset_have_reset_values());
299 for(Layout::Data_list::const_iterator p = special_outputs.begin();
300 p != special_outputs.end();
302 gold_assert((*p)->address_and_file_offset_have_reset_values());
304 gold_assert(relax_outputs.empty());
307 // Save information of SECTIONS for checking later.
310 Layout::Relaxation_debug_check::read_sections(
311 const Layout::Section_list& sections)
313 for(Layout::Section_list::const_iterator p = sections.begin();
317 Output_section* os = *p;
319 info.output_section = os;
320 info.address = os->is_address_valid() ? os->address() : 0;
321 info.data_size = os->is_data_size_valid() ? os->data_size() : -1;
322 info.offset = os->is_offset_valid()? os->offset() : -1 ;
323 this->section_infos_.push_back(info);
327 // Verify SECTIONS using previously recorded information.
330 Layout::Relaxation_debug_check::verify_sections(
331 const Layout::Section_list& sections)
334 for(Layout::Section_list::const_iterator p = sections.begin();
338 Output_section* os = *p;
339 uint64_t address = os->is_address_valid() ? os->address() : 0;
340 off_t data_size = os->is_data_size_valid() ? os->data_size() : -1;
341 off_t offset = os->is_offset_valid()? os->offset() : -1 ;
343 if (i >= this->section_infos_.size())
345 gold_fatal("Section_info of %s missing.\n", os->name());
347 const Section_info& info = this->section_infos_[i];
348 if (os != info.output_section)
349 gold_fatal("Section order changed. Expecting %s but see %s\n",
350 info.output_section->name(), os->name());
351 if (address != info.address
352 || data_size != info.data_size
353 || offset != info.offset)
354 gold_fatal("Section %s changed.\n", os->name());
358 // Layout_task_runner methods.
360 // Lay out the sections. This is called after all the input objects
364 Layout_task_runner::run(Workqueue* workqueue, const Task* task)
366 // See if any of the input definitions violate the One Definition Rule.
367 // TODO: if this is too slow, do this as a task, rather than inline.
368 this->symtab_->detect_odr_violations(task, this->options_.output_file_name());
370 Layout* layout = this->layout_;
371 off_t file_size = layout->finalize(this->input_objects_,
376 // Now we know the final size of the output file and we know where
377 // each piece of information goes.
379 if (this->mapfile_ != NULL)
381 this->mapfile_->print_discarded_sections(this->input_objects_);
382 layout->print_to_mapfile(this->mapfile_);
386 if (layout->incremental_base() == NULL)
388 of = new Output_file(parameters->options().output_file_name());
389 if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
390 of->set_is_temporary();
395 of = layout->incremental_base()->output_file();
397 // Apply the incremental relocations for symbols whose values
398 // have changed. We do this before we resize the file and start
399 // writing anything else to it, so that we can read the old
400 // incremental information from the file before (possibly)
402 if (parameters->incremental_update())
403 layout->incremental_base()->apply_incremental_relocs(this->symtab_,
407 of->resize(file_size);
410 // Queue up the final set of tasks.
411 gold::queue_final_tasks(this->options_, this->input_objects_,
412 this->symtab_, layout, workqueue, of);
417 Layout::Layout(int number_of_input_files, Script_options* script_options)
418 : number_of_input_files_(number_of_input_files),
419 script_options_(script_options),
427 unattached_section_list_(),
428 special_output_list_(),
429 relax_output_list_(),
430 section_headers_(NULL),
432 relro_segment_(NULL),
433 interp_segment_(NULL),
435 symtab_section_(NULL),
436 symtab_xindex_(NULL),
437 dynsym_section_(NULL),
438 dynsym_xindex_(NULL),
439 dynamic_section_(NULL),
440 dynamic_symbol_(NULL),
442 eh_frame_section_(NULL),
443 eh_frame_data_(NULL),
444 added_eh_frame_data_(false),
445 eh_frame_hdr_section_(NULL),
446 gdb_index_data_(NULL),
447 build_id_note_(NULL),
451 output_file_size_(-1),
452 have_added_input_section_(false),
453 sections_are_attached_(false),
454 input_requires_executable_stack_(false),
455 input_with_gnu_stack_note_(false),
456 input_without_gnu_stack_note_(false),
457 has_static_tls_(false),
458 any_postprocessing_sections_(false),
459 resized_signatures_(false),
460 have_stabstr_section_(false),
461 section_ordering_specified_(false),
462 unique_segment_for_sections_specified_(false),
463 incremental_inputs_(NULL),
464 record_output_section_data_from_script_(false),
465 script_output_section_data_list_(),
466 segment_states_(NULL),
467 relaxation_debug_check_(NULL),
468 section_order_map_(),
469 section_segment_map_(),
470 input_section_position_(),
471 input_section_glob_(),
472 incremental_base_(NULL),
475 // Make space for more than enough segments for a typical file.
476 // This is just for efficiency--it's OK if we wind up needing more.
477 this->segment_list_.reserve(12);
479 // We expect two unattached Output_data objects: the file header and
480 // the segment headers.
481 this->special_output_list_.reserve(2);
483 // Initialize structure needed for an incremental build.
484 if (parameters->incremental())
485 this->incremental_inputs_ = new Incremental_inputs;
487 // The section name pool is worth optimizing in all cases, because
488 // it is small, but there are often overlaps due to .rel sections.
489 this->namepool_.set_optimize();
492 // For incremental links, record the base file to be modified.
495 Layout::set_incremental_base(Incremental_binary* base)
497 this->incremental_base_ = base;
498 this->free_list_.init(base->output_file()->filesize(), true);
501 // Hash a key we use to look up an output section mapping.
504 Layout::Hash_key::operator()(const Layout::Key& k) const
506 return k.first + k.second.first + k.second.second;
509 // These are the debug sections that are actually used by gdb.
510 // Currently, we've checked versions of gdb up to and including 7.4.
511 // We only check the part of the name that follows ".debug_" or
514 static const char* gdb_sections[] =
517 "addr", // Fission extension
518 // "aranges", // not used by gdb as of 7.4
527 // "pubnames", // not used by gdb as of 7.4
528 // "pubtypes", // not used by gdb as of 7.4
529 // "gnu_pubnames", // Fission extension
530 // "gnu_pubtypes", // Fission extension
536 // This is the minimum set of sections needed for line numbers.
538 static const char* lines_only_debug_sections[] =
541 // "addr", // Fission extension
542 // "aranges", // not used by gdb as of 7.4
551 // "pubnames", // not used by gdb as of 7.4
552 // "pubtypes", // not used by gdb as of 7.4
553 // "gnu_pubnames", // Fission extension
554 // "gnu_pubtypes", // Fission extension
557 "str_offsets", // Fission extension
560 // These sections are the DWARF fast-lookup tables, and are not needed
561 // when building a .gdb_index section.
563 static const char* gdb_fast_lookup_sections[] =
572 // Returns whether the given debug section is in the list of
573 // debug-sections-used-by-some-version-of-gdb. SUFFIX is the
574 // portion of the name following ".debug_" or ".zdebug_".
577 is_gdb_debug_section(const char* suffix)
579 // We can do this faster: binary search or a hashtable. But why bother?
580 for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
581 if (strcmp(suffix, gdb_sections[i]) == 0)
586 // Returns whether the given section is needed for lines-only debugging.
589 is_lines_only_debug_section(const char* suffix)
591 // We can do this faster: binary search or a hashtable. But why bother?
593 i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections);
595 if (strcmp(suffix, lines_only_debug_sections[i]) == 0)
600 // Returns whether the given section is a fast-lookup section that
601 // will not be needed when building a .gdb_index section.
604 is_gdb_fast_lookup_section(const char* suffix)
606 // We can do this faster: binary search or a hashtable. But why bother?
608 i < sizeof(gdb_fast_lookup_sections)/sizeof(*gdb_fast_lookup_sections);
610 if (strcmp(suffix, gdb_fast_lookup_sections[i]) == 0)
615 // Sometimes we compress sections. This is typically done for
616 // sections that are not part of normal program execution (such as
617 // .debug_* sections), and where the readers of these sections know
618 // how to deal with compressed sections. This routine doesn't say for
619 // certain whether we'll compress -- it depends on commandline options
620 // as well -- just whether this section is a candidate for compression.
621 // (The Output_compressed_section class decides whether to compress
622 // a given section, and picks the name of the compressed section.)
625 is_compressible_debug_section(const char* secname)
627 return (is_prefix_of(".debug", secname));
630 // We may see compressed debug sections in input files. Return TRUE
631 // if this is the name of a compressed debug section.
634 is_compressed_debug_section(const char* secname)
636 return (is_prefix_of(".zdebug", secname));
640 corresponding_uncompressed_section_name(std::string secname)
642 gold_assert(secname[0] == '.' && secname[1] == 'z');
643 std::string ret(".");
644 ret.append(secname, 2, std::string::npos);
648 // Whether to include this section in the link.
650 template<int size, bool big_endian>
652 Layout::include_section(Sized_relobj_file<size, big_endian>*, const char* name,
653 const elfcpp::Shdr<size, big_endian>& shdr)
655 if (!parameters->options().relocatable()
656 && (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE))
659 elfcpp::Elf_Word sh_type = shdr.get_sh_type();
661 if ((sh_type >= elfcpp::SHT_LOOS && sh_type <= elfcpp::SHT_HIOS)
662 || (sh_type >= elfcpp::SHT_LOPROC && sh_type <= elfcpp::SHT_HIPROC))
663 return parameters->target().should_include_section(sh_type);
667 case elfcpp::SHT_NULL:
668 case elfcpp::SHT_SYMTAB:
669 case elfcpp::SHT_DYNSYM:
670 case elfcpp::SHT_HASH:
671 case elfcpp::SHT_DYNAMIC:
672 case elfcpp::SHT_SYMTAB_SHNDX:
675 case elfcpp::SHT_STRTAB:
676 // Discard the sections which have special meanings in the ELF
677 // ABI. Keep others (e.g., .stabstr). We could also do this by
678 // checking the sh_link fields of the appropriate sections.
679 return (strcmp(name, ".dynstr") != 0
680 && strcmp(name, ".strtab") != 0
681 && strcmp(name, ".shstrtab") != 0);
683 case elfcpp::SHT_RELA:
684 case elfcpp::SHT_REL:
685 case elfcpp::SHT_GROUP:
686 // If we are emitting relocations these should be handled
688 gold_assert(!parameters->options().relocatable());
691 case elfcpp::SHT_PROGBITS:
692 if (parameters->options().strip_debug()
693 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
695 if (is_debug_info_section(name))
698 if (parameters->options().strip_debug_non_line()
699 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
701 // Debugging sections can only be recognized by name.
702 if (is_prefix_of(".debug_", name)
703 && !is_lines_only_debug_section(name + 7))
705 if (is_prefix_of(".zdebug_", name)
706 && !is_lines_only_debug_section(name + 8))
709 if (parameters->options().strip_debug_gdb()
710 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
712 // Debugging sections can only be recognized by name.
713 if (is_prefix_of(".debug_", name)
714 && !is_gdb_debug_section(name + 7))
716 if (is_prefix_of(".zdebug_", name)
717 && !is_gdb_debug_section(name + 8))
720 if (parameters->options().gdb_index()
721 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
723 // When building .gdb_index, we can strip .debug_pubnames,
724 // .debug_pubtypes, and .debug_aranges sections.
725 if (is_prefix_of(".debug_", name)
726 && is_gdb_fast_lookup_section(name + 7))
728 if (is_prefix_of(".zdebug_", name)
729 && is_gdb_fast_lookup_section(name + 8))
732 if (parameters->options().strip_lto_sections()
733 && !parameters->options().relocatable()
734 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
736 // Ignore LTO sections containing intermediate code.
737 if (is_prefix_of(".gnu.lto_", name))
740 // The GNU linker strips .gnu_debuglink sections, so we do too.
741 // This is a feature used to keep debugging information in
743 if (strcmp(name, ".gnu_debuglink") == 0)
752 // Return an output section named NAME, or NULL if there is none.
755 Layout::find_output_section(const char* name) const
757 for (Section_list::const_iterator p = this->section_list_.begin();
758 p != this->section_list_.end();
760 if (strcmp((*p)->name(), name) == 0)
765 // Return an output segment of type TYPE, with segment flags SET set
766 // and segment flags CLEAR clear. Return NULL if there is none.
769 Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
770 elfcpp::Elf_Word clear) const
772 for (Segment_list::const_iterator p = this->segment_list_.begin();
773 p != this->segment_list_.end();
775 if (static_cast<elfcpp::PT>((*p)->type()) == type
776 && ((*p)->flags() & set) == set
777 && ((*p)->flags() & clear) == 0)
782 // When we put a .ctors or .dtors section with more than one word into
783 // a .init_array or .fini_array section, we need to reverse the words
784 // in the .ctors/.dtors section. This is because .init_array executes
785 // constructors front to back, where .ctors executes them back to
786 // front, and vice-versa for .fini_array/.dtors. Although we do want
787 // to remap .ctors/.dtors into .init_array/.fini_array because it can
788 // be more efficient, we don't want to change the order in which
789 // constructors/destructors are run. This set just keeps track of
790 // these sections which need to be reversed. It is only changed by
791 // Layout::layout. It should be a private member of Layout, but that
792 // would require layout.h to #include object.h to get the definition
794 static Unordered_set<Section_id, Section_id_hash> ctors_sections_in_init_array;
796 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a
797 // .init_array/.fini_array section.
800 Layout::is_ctors_in_init_array(Relobj* relobj, unsigned int shndx) const
802 return (ctors_sections_in_init_array.find(Section_id(relobj, shndx))
803 != ctors_sections_in_init_array.end());
806 // Return the output section to use for section NAME with type TYPE
807 // and section flags FLAGS. NAME must be canonicalized in the string
808 // pool, and NAME_KEY is the key. ORDER is where this should appear
809 // in the output sections. IS_RELRO is true for a relro section.
812 Layout::get_output_section(const char* name, Stringpool::Key name_key,
813 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
814 Output_section_order order, bool is_relro)
816 elfcpp::Elf_Word lookup_type = type;
818 // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and
819 // PREINIT_ARRAY like PROGBITS. This ensures that we combine
820 // .init_array, .fini_array, and .preinit_array sections by name
821 // whatever their type in the input file. We do this because the
822 // types are not always right in the input files.
823 if (lookup_type == elfcpp::SHT_INIT_ARRAY
824 || lookup_type == elfcpp::SHT_FINI_ARRAY
825 || lookup_type == elfcpp::SHT_PREINIT_ARRAY)
826 lookup_type = elfcpp::SHT_PROGBITS;
828 elfcpp::Elf_Xword lookup_flags = flags;
830 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
831 // read-write with read-only sections. Some other ELF linkers do
832 // not do this. FIXME: Perhaps there should be an option
834 lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
836 const Key key(name_key, std::make_pair(lookup_type, lookup_flags));
837 const std::pair<Key, Output_section*> v(key, NULL);
838 std::pair<Section_name_map::iterator, bool> ins(
839 this->section_name_map_.insert(v));
842 return ins.first->second;
845 // This is the first time we've seen this name/type/flags
846 // combination. For compatibility with the GNU linker, we
847 // combine sections with contents and zero flags with sections
848 // with non-zero flags. This is a workaround for cases where
849 // assembler code forgets to set section flags. FIXME: Perhaps
850 // there should be an option to control this.
851 Output_section* os = NULL;
853 if (lookup_type == elfcpp::SHT_PROGBITS)
857 Output_section* same_name = this->find_output_section(name);
858 if (same_name != NULL
859 && (same_name->type() == elfcpp::SHT_PROGBITS
860 || same_name->type() == elfcpp::SHT_INIT_ARRAY
861 || same_name->type() == elfcpp::SHT_FINI_ARRAY
862 || same_name->type() == elfcpp::SHT_PREINIT_ARRAY)
863 && (same_name->flags() & elfcpp::SHF_TLS) == 0)
866 else if ((flags & elfcpp::SHF_TLS) == 0)
868 elfcpp::Elf_Xword zero_flags = 0;
869 const Key zero_key(name_key, std::make_pair(lookup_type,
871 Section_name_map::iterator p =
872 this->section_name_map_.find(zero_key);
873 if (p != this->section_name_map_.end())
879 os = this->make_output_section(name, type, flags, order, is_relro);
881 ins.first->second = os;
886 // Returns TRUE iff NAME (an input section from RELOBJ) will
887 // be mapped to an output section that should be KEPT.
890 Layout::keep_input_section(const Relobj* relobj, const char* name)
892 if (! this->script_options_->saw_sections_clause())
895 Script_sections* ss = this->script_options_->script_sections();
896 const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
897 Output_section** output_section_slot;
898 Script_sections::Section_type script_section_type;
901 name = ss->output_section_name(file_name, name, &output_section_slot,
902 &script_section_type, &keep);
903 return name != NULL && keep;
906 // Clear the input section flags that should not be copied to the
910 Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags)
912 // Some flags in the input section should not be automatically
913 // copied to the output section.
914 input_section_flags &= ~ (elfcpp::SHF_INFO_LINK
917 | elfcpp::SHF_STRINGS);
919 // We only clear the SHF_LINK_ORDER flag in for
920 // a non-relocatable link.
921 if (!parameters->options().relocatable())
922 input_section_flags &= ~elfcpp::SHF_LINK_ORDER;
924 return input_section_flags;
927 // Pick the output section to use for section NAME, in input file
928 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
929 // linker created section. IS_INPUT_SECTION is true if we are
930 // choosing an output section for an input section found in a input
931 // file. ORDER is where this section should appear in the output
932 // sections. IS_RELRO is true for a relro section. This will return
933 // NULL if the input section should be discarded.
936 Layout::choose_output_section(const Relobj* relobj, const char* name,
937 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
938 bool is_input_section, Output_section_order order,
941 // We should not see any input sections after we have attached
942 // sections to segments.
943 gold_assert(!is_input_section || !this->sections_are_attached_);
945 flags = this->get_output_section_flags(flags);
947 if (this->script_options_->saw_sections_clause())
949 // We are using a SECTIONS clause, so the output section is
950 // chosen based only on the name.
952 Script_sections* ss = this->script_options_->script_sections();
953 const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
954 Output_section** output_section_slot;
955 Script_sections::Section_type script_section_type;
956 const char* orig_name = name;
958 name = ss->output_section_name(file_name, name, &output_section_slot,
959 &script_section_type, &keep);
963 gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' "
964 "because it is not allowed by the "
965 "SECTIONS clause of the linker script"),
967 // The SECTIONS clause says to discard this input section.
971 // We can only handle script section types ST_NONE and ST_NOLOAD.
972 switch (script_section_type)
974 case Script_sections::ST_NONE:
976 case Script_sections::ST_NOLOAD:
977 flags &= elfcpp::SHF_ALLOC;
983 // If this is an orphan section--one not mentioned in the linker
984 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
985 // default processing below.
987 if (output_section_slot != NULL)
989 if (*output_section_slot != NULL)
991 (*output_section_slot)->update_flags_for_input_section(flags);
992 return *output_section_slot;
995 // We don't put sections found in the linker script into
996 // SECTION_NAME_MAP_. That keeps us from getting confused
997 // if an orphan section is mapped to a section with the same
998 // name as one in the linker script.
1000 name = this->namepool_.add(name, false, NULL);
1002 Output_section* os = this->make_output_section(name, type, flags,
1005 os->set_found_in_sections_clause();
1007 // Special handling for NOLOAD sections.
1008 if (script_section_type == Script_sections::ST_NOLOAD)
1010 os->set_is_noload();
1012 // The constructor of Output_section sets addresses of non-ALLOC
1013 // sections to 0 by default. We don't want that for NOLOAD
1014 // sections even if they have no SHF_ALLOC flag.
1015 if ((os->flags() & elfcpp::SHF_ALLOC) == 0
1016 && os->is_address_valid())
1018 gold_assert(os->address() == 0
1019 && !os->is_offset_valid()
1020 && !os->is_data_size_valid());
1021 os->reset_address_and_file_offset();
1025 *output_section_slot = os;
1030 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
1032 size_t len = strlen(name);
1033 std::string uncompressed_name;
1035 // Compressed debug sections should be mapped to the corresponding
1036 // uncompressed section.
1037 if (is_compressed_debug_section(name))
1040 corresponding_uncompressed_section_name(std::string(name, len));
1041 name = uncompressed_name.c_str();
1042 len = uncompressed_name.length();
1045 // Turn NAME from the name of the input section into the name of the
1047 if (is_input_section
1048 && !this->script_options_->saw_sections_clause()
1049 && !parameters->options().relocatable())
1051 const char *orig_name = name;
1052 name = parameters->target().output_section_name(relobj, name, &len);
1054 name = Layout::output_section_name(relobj, orig_name, &len);
1057 Stringpool::Key name_key;
1058 name = this->namepool_.add_with_length(name, len, true, &name_key);
1060 // Find or make the output section. The output section is selected
1061 // based on the section name, type, and flags.
1062 return this->get_output_section(name, name_key, type, flags, order, is_relro);
1065 // For incremental links, record the initial fixed layout of a section
1066 // from the base file, and return a pointer to the Output_section.
1068 template<int size, bool big_endian>
1070 Layout::init_fixed_output_section(const char* name,
1071 elfcpp::Shdr<size, big_endian>& shdr)
1073 unsigned int sh_type = shdr.get_sh_type();
1075 // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY,
1076 // PRE_INIT_ARRAY, and NOTE sections.
1077 // All others will be created from scratch and reallocated.
1078 if (!can_incremental_update(sh_type))
1081 // If we're generating a .gdb_index section, we need to regenerate
1083 if (parameters->options().gdb_index()
1084 && sh_type == elfcpp::SHT_PROGBITS
1085 && strcmp(name, ".gdb_index") == 0)
1088 typename elfcpp::Elf_types<size>::Elf_Addr sh_addr = shdr.get_sh_addr();
1089 typename elfcpp::Elf_types<size>::Elf_Off sh_offset = shdr.get_sh_offset();
1090 typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
1091 typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
1092 typename elfcpp::Elf_types<size>::Elf_WXword sh_addralign =
1093 shdr.get_sh_addralign();
1095 // Make the output section.
1096 Stringpool::Key name_key;
1097 name = this->namepool_.add(name, true, &name_key);
1098 Output_section* os = this->get_output_section(name, name_key, sh_type,
1099 sh_flags, ORDER_INVALID, false);
1100 os->set_fixed_layout(sh_addr, sh_offset, sh_size, sh_addralign);
1101 if (sh_type != elfcpp::SHT_NOBITS)
1102 this->free_list_.remove(sh_offset, sh_offset + sh_size);
1106 // Return the index by which an input section should be ordered. This
1107 // is used to sort some .text sections, for compatibility with GNU ld.
1110 Layout::special_ordering_of_input_section(const char* name)
1112 // The GNU linker has some special handling for some sections that
1113 // wind up in the .text section. Sections that start with these
1114 // prefixes must appear first, and must appear in the order listed
1116 static const char* const text_section_sort[] =
1125 i < sizeof(text_section_sort) / sizeof(text_section_sort[0]);
1127 if (is_prefix_of(text_section_sort[i], name))
1133 // Return the output section to use for input section SHNDX, with name
1134 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
1135 // index of a relocation section which applies to this section, or 0
1136 // if none, or -1U if more than one. RELOC_TYPE is the type of the
1137 // relocation section if there is one. Set *OFF to the offset of this
1138 // input section without the output section. Return NULL if the
1139 // section should be discarded. Set *OFF to -1 if the section
1140 // contents should not be written directly to the output file, but
1141 // will instead receive special handling.
1143 template<int size, bool big_endian>
1145 Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
1146 const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
1147 unsigned int reloc_shndx, unsigned int, off_t* off)
1151 if (!this->include_section(object, name, shdr))
1154 elfcpp::Elf_Word sh_type = shdr.get_sh_type();
1156 // In a relocatable link a grouped section must not be combined with
1157 // any other sections.
1159 if (parameters->options().relocatable()
1160 && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
1162 name = this->namepool_.add(name, true, NULL);
1163 os = this->make_output_section(name, sh_type, shdr.get_sh_flags(),
1164 ORDER_INVALID, false);
1168 // Plugins can choose to place one or more subsets of sections in
1169 // unique segments and this is done by mapping these section subsets
1170 // to unique output sections. Check if this section needs to be
1171 // remapped to a unique output section.
1172 Section_segment_map::iterator it
1173 = this->section_segment_map_.find(Const_section_id(object, shndx));
1174 if (it == this->section_segment_map_.end())
1176 os = this->choose_output_section(object, name, sh_type,
1177 shdr.get_sh_flags(), true,
1178 ORDER_INVALID, false);
1182 // We know the name of the output section, directly call
1183 // get_output_section here by-passing choose_output_section.
1184 elfcpp::Elf_Xword flags
1185 = this->get_output_section_flags(shdr.get_sh_flags());
1187 const char* os_name = it->second->name;
1188 Stringpool::Key name_key;
1189 os_name = this->namepool_.add(os_name, true, &name_key);
1190 os = this->get_output_section(os_name, name_key, sh_type, flags,
1191 ORDER_INVALID, false);
1192 if (!os->is_unique_segment())
1194 os->set_is_unique_segment();
1195 os->set_extra_segment_flags(it->second->flags);
1196 os->set_segment_alignment(it->second->align);
1203 // By default the GNU linker sorts input sections whose names match
1204 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The
1205 // sections are sorted by name. This is used to implement
1206 // constructor priority ordering. We are compatible. When we put
1207 // .ctor sections in .init_array and .dtor sections in .fini_array,
1208 // we must also sort plain .ctor and .dtor sections.
1209 if (!this->script_options_->saw_sections_clause()
1210 && !parameters->options().relocatable()
1211 && (is_prefix_of(".ctors.", name)
1212 || is_prefix_of(".dtors.", name)
1213 || is_prefix_of(".init_array.", name)
1214 || is_prefix_of(".fini_array.", name)
1215 || (parameters->options().ctors_in_init_array()
1216 && (strcmp(name, ".ctors") == 0
1217 || strcmp(name, ".dtors") == 0))))
1218 os->set_must_sort_attached_input_sections();
1220 // By default the GNU linker sorts some special text sections ahead
1221 // of others. We are compatible.
1222 if (parameters->options().text_reorder()
1223 && !this->script_options_->saw_sections_clause()
1224 && !this->is_section_ordering_specified()
1225 && !parameters->options().relocatable()
1226 && Layout::special_ordering_of_input_section(name) >= 0)
1227 os->set_must_sort_attached_input_sections();
1229 // If this is a .ctors or .ctors.* section being mapped to a
1230 // .init_array section, or a .dtors or .dtors.* section being mapped
1231 // to a .fini_array section, we will need to reverse the words if
1232 // there is more than one. Record this section for later. See
1233 // ctors_sections_in_init_array above.
1234 if (!this->script_options_->saw_sections_clause()
1235 && !parameters->options().relocatable()
1236 && shdr.get_sh_size() > size / 8
1237 && (((strcmp(name, ".ctors") == 0
1238 || is_prefix_of(".ctors.", name))
1239 && strcmp(os->name(), ".init_array") == 0)
1240 || ((strcmp(name, ".dtors") == 0
1241 || is_prefix_of(".dtors.", name))
1242 && strcmp(os->name(), ".fini_array") == 0)))
1243 ctors_sections_in_init_array.insert(Section_id(object, shndx));
1245 // FIXME: Handle SHF_LINK_ORDER somewhere.
1247 elfcpp::Elf_Xword orig_flags = os->flags();
1249 *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
1250 this->script_options_->saw_sections_clause());
1252 // If the flags changed, we may have to change the order.
1253 if ((orig_flags & elfcpp::SHF_ALLOC) != 0)
1255 orig_flags &= (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
1256 elfcpp::Elf_Xword new_flags =
1257 os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
1258 if (orig_flags != new_flags)
1259 os->set_order(this->default_section_order(os, false));
1262 this->have_added_input_section_ = true;
1267 // Maps section SECN to SEGMENT s.
1269 Layout::insert_section_segment_map(Const_section_id secn,
1270 Unique_segment_info *s)
1272 gold_assert(this->unique_segment_for_sections_specified_);
1273 this->section_segment_map_[secn] = s;
1276 // Handle a relocation section when doing a relocatable link.
1278 template<int size, bool big_endian>
1280 Layout::layout_reloc(Sized_relobj_file<size, big_endian>* object,
1282 const elfcpp::Shdr<size, big_endian>& shdr,
1283 Output_section* data_section,
1284 Relocatable_relocs* rr)
1286 gold_assert(parameters->options().relocatable()
1287 || parameters->options().emit_relocs());
1289 int sh_type = shdr.get_sh_type();
1292 if (sh_type == elfcpp::SHT_REL)
1294 else if (sh_type == elfcpp::SHT_RELA)
1298 name += data_section->name();
1300 // In a relocatable link relocs for a grouped section must not be
1301 // combined with other reloc sections.
1303 if (!parameters->options().relocatable()
1304 || (data_section->flags() & elfcpp::SHF_GROUP) == 0)
1305 os = this->choose_output_section(object, name.c_str(), sh_type,
1306 shdr.get_sh_flags(), false,
1307 ORDER_INVALID, false);
1310 const char* n = this->namepool_.add(name.c_str(), true, NULL);
1311 os = this->make_output_section(n, sh_type, shdr.get_sh_flags(),
1312 ORDER_INVALID, false);
1315 os->set_should_link_to_symtab();
1316 os->set_info_section(data_section);
1318 Output_section_data* posd;
1319 if (sh_type == elfcpp::SHT_REL)
1321 os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
1322 posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
1326 else if (sh_type == elfcpp::SHT_RELA)
1328 os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
1329 posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
1336 os->add_output_section_data(posd);
1337 rr->set_output_data(posd);
1342 // Handle a group section when doing a relocatable link.
1344 template<int size, bool big_endian>
1346 Layout::layout_group(Symbol_table* symtab,
1347 Sized_relobj_file<size, big_endian>* object,
1349 const char* group_section_name,
1350 const char* signature,
1351 const elfcpp::Shdr<size, big_endian>& shdr,
1352 elfcpp::Elf_Word flags,
1353 std::vector<unsigned int>* shndxes)
1355 gold_assert(parameters->options().relocatable());
1356 gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
1357 group_section_name = this->namepool_.add(group_section_name, true, NULL);
1358 Output_section* os = this->make_output_section(group_section_name,
1360 shdr.get_sh_flags(),
1361 ORDER_INVALID, false);
1363 // We need to find a symbol with the signature in the symbol table.
1364 // If we don't find one now, we need to look again later.
1365 Symbol* sym = symtab->lookup(signature, NULL);
1367 os->set_info_symndx(sym);
1370 // Reserve some space to minimize reallocations.
1371 if (this->group_signatures_.empty())
1372 this->group_signatures_.reserve(this->number_of_input_files_ * 16);
1374 // We will wind up using a symbol whose name is the signature.
1375 // So just put the signature in the symbol name pool to save it.
1376 signature = symtab->canonicalize_name(signature);
1377 this->group_signatures_.push_back(Group_signature(os, signature));
1380 os->set_should_link_to_symtab();
1383 section_size_type entry_count =
1384 convert_to_section_size_type(shdr.get_sh_size() / 4);
1385 Output_section_data* posd =
1386 new Output_data_group<size, big_endian>(object, entry_count, flags,
1388 os->add_output_section_data(posd);
1391 // Special GNU handling of sections name .eh_frame. They will
1392 // normally hold exception frame data as defined by the C++ ABI
1393 // (http://codesourcery.com/cxx-abi/).
1395 template<int size, bool big_endian>
1397 Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
1398 const unsigned char* symbols,
1400 const unsigned char* symbol_names,
1401 off_t symbol_names_size,
1403 const elfcpp::Shdr<size, big_endian>& shdr,
1404 unsigned int reloc_shndx, unsigned int reloc_type,
1407 gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS
1408 || shdr.get_sh_type() == elfcpp::SHT_X86_64_UNWIND);
1409 gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
1411 Output_section* os = this->make_eh_frame_section(object);
1415 gold_assert(this->eh_frame_section_ == os);
1417 elfcpp::Elf_Xword orig_flags = os->flags();
1419 Eh_frame::Eh_frame_section_disposition disp =
1420 Eh_frame::EH_UNRECOGNIZED_SECTION;
1421 if (!parameters->incremental())
1423 disp = this->eh_frame_data_->add_ehframe_input_section(object,
1433 if (disp == Eh_frame::EH_OPTIMIZABLE_SECTION)
1435 os->update_flags_for_input_section(shdr.get_sh_flags());
1437 // A writable .eh_frame section is a RELRO section.
1438 if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1439 != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1442 os->set_order(ORDER_RELRO);
1449 if (disp == Eh_frame::EH_END_MARKER_SECTION && !this->added_eh_frame_data_)
1451 // We found the end marker section, so now we can add the set of
1452 // optimized sections to the output section. We need to postpone
1453 // adding this until we've found a section we can optimize so that
1454 // the .eh_frame section in crtbeginT.o winds up at the start of
1455 // the output section.
1456 os->add_output_section_data(this->eh_frame_data_);
1457 this->added_eh_frame_data_ = true;
1460 // We couldn't handle this .eh_frame section for some reason.
1461 // Add it as a normal section.
1462 bool saw_sections_clause = this->script_options_->saw_sections_clause();
1463 *off = os->add_input_section(this, object, shndx, ".eh_frame", shdr,
1464 reloc_shndx, saw_sections_clause);
1465 this->have_added_input_section_ = true;
1467 if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1468 != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1469 os->set_order(this->default_section_order(os, false));
1475 Layout::finalize_eh_frame_section()
1477 // If we never found an end marker section, we need to add the
1478 // optimized eh sections to the output section now.
1479 if (!parameters->incremental()
1480 && this->eh_frame_section_ != NULL
1481 && !this->added_eh_frame_data_)
1483 this->eh_frame_section_->add_output_section_data(this->eh_frame_data_);
1484 this->added_eh_frame_data_ = true;
1488 // Create and return the magic .eh_frame section. Create
1489 // .eh_frame_hdr also if appropriate. OBJECT is the object with the
1490 // input .eh_frame section; it may be NULL.
1493 Layout::make_eh_frame_section(const Relobj* object)
1495 // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than
1497 Output_section* os = this->choose_output_section(object, ".eh_frame",
1498 elfcpp::SHT_PROGBITS,
1499 elfcpp::SHF_ALLOC, false,
1500 ORDER_EHFRAME, false);
1504 if (this->eh_frame_section_ == NULL)
1506 this->eh_frame_section_ = os;
1507 this->eh_frame_data_ = new Eh_frame();
1509 // For incremental linking, we do not optimize .eh_frame sections
1510 // or create a .eh_frame_hdr section.
1511 if (parameters->options().eh_frame_hdr() && !parameters->incremental())
1513 Output_section* hdr_os =
1514 this->choose_output_section(NULL, ".eh_frame_hdr",
1515 elfcpp::SHT_PROGBITS,
1516 elfcpp::SHF_ALLOC, false,
1517 ORDER_EHFRAME, false);
1521 Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
1522 this->eh_frame_data_);
1523 hdr_os->add_output_section_data(hdr_posd);
1525 hdr_os->set_after_input_sections();
1527 if (!this->script_options_->saw_phdrs_clause())
1529 Output_segment* hdr_oseg;
1530 hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
1532 hdr_oseg->add_output_section_to_nonload(hdr_os,
1536 this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
1544 // Add an exception frame for a PLT. This is called from target code.
1547 Layout::add_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data,
1548 size_t cie_length, const unsigned char* fde_data,
1551 if (parameters->incremental())
1553 // FIXME: Maybe this could work some day....
1556 Output_section* os = this->make_eh_frame_section(NULL);
1559 this->eh_frame_data_->add_ehframe_for_plt(plt, cie_data, cie_length,
1560 fde_data, fde_length);
1561 if (!this->added_eh_frame_data_)
1563 os->add_output_section_data(this->eh_frame_data_);
1564 this->added_eh_frame_data_ = true;
1568 // Scan a .debug_info or .debug_types section, and add summary
1569 // information to the .gdb_index section.
1571 template<int size, bool big_endian>
1573 Layout::add_to_gdb_index(bool is_type_unit,
1574 Sized_relobj<size, big_endian>* object,
1575 const unsigned char* symbols,
1578 unsigned int reloc_shndx,
1579 unsigned int reloc_type)
1581 if (this->gdb_index_data_ == NULL)
1583 Output_section* os = this->choose_output_section(NULL, ".gdb_index",
1584 elfcpp::SHT_PROGBITS, 0,
1585 false, ORDER_INVALID,
1590 this->gdb_index_data_ = new Gdb_index(os);
1591 os->add_output_section_data(this->gdb_index_data_);
1592 os->set_after_input_sections();
1595 this->gdb_index_data_->scan_debug_info(is_type_unit, object, symbols,
1596 symbols_size, shndx, reloc_shndx,
1600 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1601 // the output section.
1604 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
1605 elfcpp::Elf_Xword flags,
1606 Output_section_data* posd,
1607 Output_section_order order, bool is_relro)
1609 Output_section* os = this->choose_output_section(NULL, name, type, flags,
1610 false, order, is_relro);
1612 os->add_output_section_data(posd);
1616 // Map section flags to segment flags.
1619 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
1621 elfcpp::Elf_Word ret = elfcpp::PF_R;
1622 if ((flags & elfcpp::SHF_WRITE) != 0)
1623 ret |= elfcpp::PF_W;
1624 if ((flags & elfcpp::SHF_EXECINSTR) != 0)
1625 ret |= elfcpp::PF_X;
1629 // Make a new Output_section, and attach it to segments as
1630 // appropriate. ORDER is the order in which this section should
1631 // appear in the output segment. IS_RELRO is true if this is a relro
1632 // (read-only after relocations) section.
1635 Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
1636 elfcpp::Elf_Xword flags,
1637 Output_section_order order, bool is_relro)
1640 if ((flags & elfcpp::SHF_ALLOC) == 0
1641 && strcmp(parameters->options().compress_debug_sections(), "none") != 0
1642 && is_compressible_debug_section(name))
1643 os = new Output_compressed_section(¶meters->options(), name, type,
1645 else if ((flags & elfcpp::SHF_ALLOC) == 0
1646 && parameters->options().strip_debug_non_line()
1647 && strcmp(".debug_abbrev", name) == 0)
1649 os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
1651 if (this->debug_info_)
1652 this->debug_info_->set_abbreviations(this->debug_abbrev_);
1654 else if ((flags & elfcpp::SHF_ALLOC) == 0
1655 && parameters->options().strip_debug_non_line()
1656 && strcmp(".debug_info", name) == 0)
1658 os = this->debug_info_ = new Output_reduced_debug_info_section(
1660 if (this->debug_abbrev_)
1661 this->debug_info_->set_abbreviations(this->debug_abbrev_);
1665 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1666 // not have correct section types. Force them here.
1667 if (type == elfcpp::SHT_PROGBITS)
1669 if (is_prefix_of(".init_array", name))
1670 type = elfcpp::SHT_INIT_ARRAY;
1671 else if (is_prefix_of(".preinit_array", name))
1672 type = elfcpp::SHT_PREINIT_ARRAY;
1673 else if (is_prefix_of(".fini_array", name))
1674 type = elfcpp::SHT_FINI_ARRAY;
1677 // FIXME: const_cast is ugly.
1678 Target* target = const_cast<Target*>(¶meters->target());
1679 os = target->make_output_section(name, type, flags);
1682 // With -z relro, we have to recognize the special sections by name.
1683 // There is no other way.
1684 bool is_relro_local = false;
1685 if (!this->script_options_->saw_sections_clause()
1686 && parameters->options().relro()
1687 && (flags & elfcpp::SHF_ALLOC) != 0
1688 && (flags & elfcpp::SHF_WRITE) != 0)
1690 if (type == elfcpp::SHT_PROGBITS)
1692 if ((flags & elfcpp::SHF_TLS) != 0)
1694 else if (strcmp(name, ".data.rel.ro") == 0)
1696 else if (strcmp(name, ".data.rel.ro.local") == 0)
1699 is_relro_local = true;
1701 else if (strcmp(name, ".ctors") == 0
1702 || strcmp(name, ".dtors") == 0
1703 || strcmp(name, ".jcr") == 0)
1706 else if (type == elfcpp::SHT_INIT_ARRAY
1707 || type == elfcpp::SHT_FINI_ARRAY
1708 || type == elfcpp::SHT_PREINIT_ARRAY)
1715 if (order == ORDER_INVALID && (flags & elfcpp::SHF_ALLOC) != 0)
1716 order = this->default_section_order(os, is_relro_local);
1718 os->set_order(order);
1720 parameters->target().new_output_section(os);
1722 this->section_list_.push_back(os);
1724 // The GNU linker by default sorts some sections by priority, so we
1725 // do the same. We need to know that this might happen before we
1726 // attach any input sections.
1727 if (!this->script_options_->saw_sections_clause()
1728 && !parameters->options().relocatable()
1729 && (strcmp(name, ".init_array") == 0
1730 || strcmp(name, ".fini_array") == 0
1731 || (!parameters->options().ctors_in_init_array()
1732 && (strcmp(name, ".ctors") == 0
1733 || strcmp(name, ".dtors") == 0))))
1734 os->set_may_sort_attached_input_sections();
1736 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1737 // sections before other .text sections. We are compatible. We
1738 // need to know that this might happen before we attach any input
1740 if (parameters->options().text_reorder()
1741 && !this->script_options_->saw_sections_clause()
1742 && !this->is_section_ordering_specified()
1743 && !parameters->options().relocatable()
1744 && strcmp(name, ".text") == 0)
1745 os->set_may_sort_attached_input_sections();
1747 // GNU linker sorts section by name with --sort-section=name.
1748 if (strcmp(parameters->options().sort_section(), "name") == 0)
1749 os->set_must_sort_attached_input_sections();
1751 // Check for .stab*str sections, as .stab* sections need to link to
1753 if (type == elfcpp::SHT_STRTAB
1754 && !this->have_stabstr_section_
1755 && strncmp(name, ".stab", 5) == 0
1756 && strcmp(name + strlen(name) - 3, "str") == 0)
1757 this->have_stabstr_section_ = true;
1759 // During a full incremental link, we add patch space to most
1760 // PROGBITS and NOBITS sections. Flag those that may be
1761 // arbitrarily padded.
1762 if ((type == elfcpp::SHT_PROGBITS || type == elfcpp::SHT_NOBITS)
1763 && order != ORDER_INTERP
1764 && order != ORDER_INIT
1765 && order != ORDER_PLT
1766 && order != ORDER_FINI
1767 && order != ORDER_RELRO_LAST
1768 && order != ORDER_NON_RELRO_FIRST
1769 && strcmp(name, ".eh_frame") != 0
1770 && strcmp(name, ".ctors") != 0
1771 && strcmp(name, ".dtors") != 0
1772 && strcmp(name, ".jcr") != 0)
1774 os->set_is_patch_space_allowed();
1776 // Certain sections require "holes" to be filled with
1777 // specific fill patterns. These fill patterns may have
1778 // a minimum size, so we must prevent allocations from the
1779 // free list that leave a hole smaller than the minimum.
1780 if (strcmp(name, ".debug_info") == 0)
1781 os->set_free_space_fill(new Output_fill_debug_info(false));
1782 else if (strcmp(name, ".debug_types") == 0)
1783 os->set_free_space_fill(new Output_fill_debug_info(true));
1784 else if (strcmp(name, ".debug_line") == 0)
1785 os->set_free_space_fill(new Output_fill_debug_line());
1788 // If we have already attached the sections to segments, then we
1789 // need to attach this one now. This happens for sections created
1790 // directly by the linker.
1791 if (this->sections_are_attached_)
1792 this->attach_section_to_segment(¶meters->target(), os);
1797 // Return the default order in which a section should be placed in an
1798 // output segment. This function captures a lot of the ideas in
1799 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1800 // linker created section is normally set when the section is created;
1801 // this function is used for input sections.
1803 Output_section_order
1804 Layout::default_section_order(Output_section* os, bool is_relro_local)
1806 gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
1807 bool is_write = (os->flags() & elfcpp::SHF_WRITE) != 0;
1808 bool is_execinstr = (os->flags() & elfcpp::SHF_EXECINSTR) != 0;
1809 bool is_bss = false;
1814 case elfcpp::SHT_PROGBITS:
1816 case elfcpp::SHT_NOBITS:
1819 case elfcpp::SHT_RELA:
1820 case elfcpp::SHT_REL:
1822 return ORDER_DYNAMIC_RELOCS;
1824 case elfcpp::SHT_HASH:
1825 case elfcpp::SHT_DYNAMIC:
1826 case elfcpp::SHT_SHLIB:
1827 case elfcpp::SHT_DYNSYM:
1828 case elfcpp::SHT_GNU_HASH:
1829 case elfcpp::SHT_GNU_verdef:
1830 case elfcpp::SHT_GNU_verneed:
1831 case elfcpp::SHT_GNU_versym:
1833 return ORDER_DYNAMIC_LINKER;
1835 case elfcpp::SHT_NOTE:
1836 return is_write ? ORDER_RW_NOTE : ORDER_RO_NOTE;
1839 if ((os->flags() & elfcpp::SHF_TLS) != 0)
1840 return is_bss ? ORDER_TLS_BSS : ORDER_TLS_DATA;
1842 if (!is_bss && !is_write)
1846 if (strcmp(os->name(), ".init") == 0)
1848 else if (strcmp(os->name(), ".fini") == 0)
1851 return is_execinstr ? ORDER_TEXT : ORDER_READONLY;
1855 return is_relro_local ? ORDER_RELRO_LOCAL : ORDER_RELRO;
1857 if (os->is_small_section())
1858 return is_bss ? ORDER_SMALL_BSS : ORDER_SMALL_DATA;
1859 if (os->is_large_section())
1860 return is_bss ? ORDER_LARGE_BSS : ORDER_LARGE_DATA;
1862 return is_bss ? ORDER_BSS : ORDER_DATA;
1865 // Attach output sections to segments. This is called after we have
1866 // seen all the input sections.
1869 Layout::attach_sections_to_segments(const Target* target)
1871 for (Section_list::iterator p = this->section_list_.begin();
1872 p != this->section_list_.end();
1874 this->attach_section_to_segment(target, *p);
1876 this->sections_are_attached_ = true;
1879 // Attach an output section to a segment.
1882 Layout::attach_section_to_segment(const Target* target, Output_section* os)
1884 if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
1885 this->unattached_section_list_.push_back(os);
1887 this->attach_allocated_section_to_segment(target, os);
1890 // Attach an allocated output section to a segment.
1893 Layout::attach_allocated_section_to_segment(const Target* target,
1896 elfcpp::Elf_Xword flags = os->flags();
1897 gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
1899 if (parameters->options().relocatable())
1902 // If we have a SECTIONS clause, we can't handle the attachment to
1903 // segments until after we've seen all the sections.
1904 if (this->script_options_->saw_sections_clause())
1907 gold_assert(!this->script_options_->saw_phdrs_clause());
1909 // This output section goes into a PT_LOAD segment.
1911 elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
1913 // If this output section's segment has extra flags that need to be set,
1914 // coming from a linker plugin, do that.
1915 seg_flags |= os->extra_segment_flags();
1917 // Check for --section-start.
1919 bool is_address_set = parameters->options().section_start(os->name(), &addr);
1921 // In general the only thing we really care about for PT_LOAD
1922 // segments is whether or not they are writable or executable,
1923 // so that is how we search for them.
1924 // Large data sections also go into their own PT_LOAD segment.
1925 // People who need segments sorted on some other basis will
1926 // have to use a linker script.
1928 Segment_list::const_iterator p;
1929 if (!os->is_unique_segment())
1931 for (p = this->segment_list_.begin();
1932 p != this->segment_list_.end();
1935 if ((*p)->type() != elfcpp::PT_LOAD)
1937 if ((*p)->is_unique_segment())
1939 if (!parameters->options().omagic()
1940 && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
1942 if ((target->isolate_execinstr() || parameters->options().rosegment())
1943 && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
1945 // If -Tbss was specified, we need to separate the data and BSS
1947 if (parameters->options().user_set_Tbss())
1949 if ((os->type() == elfcpp::SHT_NOBITS)
1950 == (*p)->has_any_data_sections())
1953 if (os->is_large_data_section() && !(*p)->is_large_data_segment())
1958 if ((*p)->are_addresses_set())
1961 (*p)->add_initial_output_data(os);
1962 (*p)->update_flags_for_output_section(seg_flags);
1963 (*p)->set_addresses(addr, addr);
1967 (*p)->add_output_section_to_load(this, os, seg_flags);
1972 if (p == this->segment_list_.end()
1973 || os->is_unique_segment())
1975 Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
1977 if (os->is_large_data_section())
1978 oseg->set_is_large_data_segment();
1979 oseg->add_output_section_to_load(this, os, seg_flags);
1981 oseg->set_addresses(addr, addr);
1982 // Check if segment should be marked unique. For segments marked
1983 // unique by linker plugins, set the new alignment if specified.
1984 if (os->is_unique_segment())
1986 oseg->set_is_unique_segment();
1987 if (os->segment_alignment() != 0)
1988 oseg->set_minimum_p_align(os->segment_alignment());
1992 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1994 if (os->type() == elfcpp::SHT_NOTE)
1996 // See if we already have an equivalent PT_NOTE segment.
1997 for (p = this->segment_list_.begin();
1998 p != segment_list_.end();
2001 if ((*p)->type() == elfcpp::PT_NOTE
2002 && (((*p)->flags() & elfcpp::PF_W)
2003 == (seg_flags & elfcpp::PF_W)))
2005 (*p)->add_output_section_to_nonload(os, seg_flags);
2010 if (p == this->segment_list_.end())
2012 Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
2014 oseg->add_output_section_to_nonload(os, seg_flags);
2018 // If we see a loadable SHF_TLS section, we create a PT_TLS
2019 // segment. There can only be one such segment.
2020 if ((flags & elfcpp::SHF_TLS) != 0)
2022 if (this->tls_segment_ == NULL)
2023 this->make_output_segment(elfcpp::PT_TLS, seg_flags);
2024 this->tls_segment_->add_output_section_to_nonload(os, seg_flags);
2027 // If -z relro is in effect, and we see a relro section, we create a
2028 // PT_GNU_RELRO segment. There can only be one such segment.
2029 if (os->is_relro() && parameters->options().relro())
2031 gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
2032 if (this->relro_segment_ == NULL)
2033 this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
2034 this->relro_segment_->add_output_section_to_nonload(os, seg_flags);
2037 // If we see a section named .interp, put it into a PT_INTERP
2038 // segment. This seems broken to me, but this is what GNU ld does,
2039 // and glibc expects it.
2040 if (strcmp(os->name(), ".interp") == 0
2041 && !this->script_options_->saw_phdrs_clause())
2043 if (this->interp_segment_ == NULL)
2044 this->make_output_segment(elfcpp::PT_INTERP, seg_flags);
2046 gold_warning(_("multiple '.interp' sections in input files "
2047 "may cause confusing PT_INTERP segment"));
2048 this->interp_segment_->add_output_section_to_nonload(os, seg_flags);
2052 // Make an output section for a script.
2055 Layout::make_output_section_for_script(
2057 Script_sections::Section_type section_type)
2059 name = this->namepool_.add(name, false, NULL);
2060 elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC;
2061 if (section_type == Script_sections::ST_NOLOAD)
2063 Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
2064 sh_flags, ORDER_INVALID,
2066 os->set_found_in_sections_clause();
2067 if (section_type == Script_sections::ST_NOLOAD)
2068 os->set_is_noload();
2072 // Return the number of segments we expect to see.
2075 Layout::expected_segment_count() const
2077 size_t ret = this->segment_list_.size();
2079 // If we didn't see a SECTIONS clause in a linker script, we should
2080 // already have the complete list of segments. Otherwise we ask the
2081 // SECTIONS clause how many segments it expects, and add in the ones
2082 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
2084 if (!this->script_options_->saw_sections_clause())
2088 const Script_sections* ss = this->script_options_->script_sections();
2089 return ret + ss->expected_segment_count(this);
2093 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
2094 // is whether we saw a .note.GNU-stack section in the object file.
2095 // GNU_STACK_FLAGS is the section flags. The flags give the
2096 // protection required for stack memory. We record this in an
2097 // executable as a PT_GNU_STACK segment. If an object file does not
2098 // have a .note.GNU-stack segment, we must assume that it is an old
2099 // object. On some targets that will force an executable stack.
2102 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags,
2105 if (!seen_gnu_stack)
2107 this->input_without_gnu_stack_note_ = true;
2108 if (parameters->options().warn_execstack()
2109 && parameters->target().is_default_stack_executable())
2110 gold_warning(_("%s: missing .note.GNU-stack section"
2111 " implies executable stack"),
2112 obj->name().c_str());
2116 this->input_with_gnu_stack_note_ = true;
2117 if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
2119 this->input_requires_executable_stack_ = true;
2120 if (parameters->options().warn_execstack())
2121 gold_warning(_("%s: requires executable stack"),
2122 obj->name().c_str());
2127 // Create automatic note sections.
2130 Layout::create_notes()
2132 this->create_gold_note();
2133 this->create_executable_stack_info();
2134 this->create_build_id();
2137 // Create the dynamic sections which are needed before we read the
2141 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
2143 if (parameters->doing_static_link())
2146 this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
2147 elfcpp::SHT_DYNAMIC,
2149 | elfcpp::SHF_WRITE),
2153 // A linker script may discard .dynamic, so check for NULL.
2154 if (this->dynamic_section_ != NULL)
2156 this->dynamic_symbol_ =
2157 symtab->define_in_output_data("_DYNAMIC", NULL,
2158 Symbol_table::PREDEFINED,
2159 this->dynamic_section_, 0, 0,
2160 elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
2161 elfcpp::STV_HIDDEN, 0, false, false);
2163 this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_);
2165 this->dynamic_section_->add_output_section_data(this->dynamic_data_);
2169 // For each output section whose name can be represented as C symbol,
2170 // define __start and __stop symbols for the section. This is a GNU
2174 Layout::define_section_symbols(Symbol_table* symtab)
2176 for (Section_list::const_iterator p = this->section_list_.begin();
2177 p != this->section_list_.end();
2180 const char* const name = (*p)->name();
2181 if (is_cident(name))
2183 const std::string name_string(name);
2184 const std::string start_name(cident_section_start_prefix
2186 const std::string stop_name(cident_section_stop_prefix
2189 symtab->define_in_output_data(start_name.c_str(),
2191 Symbol_table::PREDEFINED,
2197 elfcpp::STV_DEFAULT,
2199 false, // offset_is_from_end
2200 true); // only_if_ref
2202 symtab->define_in_output_data(stop_name.c_str(),
2204 Symbol_table::PREDEFINED,
2210 elfcpp::STV_DEFAULT,
2212 true, // offset_is_from_end
2213 true); // only_if_ref
2218 // Define symbols for group signatures.
2221 Layout::define_group_signatures(Symbol_table* symtab)
2223 for (Group_signatures::iterator p = this->group_signatures_.begin();
2224 p != this->group_signatures_.end();
2227 Symbol* sym = symtab->lookup(p->signature, NULL);
2229 p->section->set_info_symndx(sym);
2232 // Force the name of the group section to the group
2233 // signature, and use the group's section symbol as the
2234 // signature symbol.
2235 if (strcmp(p->section->name(), p->signature) != 0)
2237 const char* name = this->namepool_.add(p->signature,
2239 p->section->set_name(name);
2241 p->section->set_needs_symtab_index();
2242 p->section->set_info_section_symndx(p->section);
2246 this->group_signatures_.clear();
2249 // Find the first read-only PT_LOAD segment, creating one if
2253 Layout::find_first_load_seg(const Target* target)
2255 Output_segment* best = NULL;
2256 for (Segment_list::const_iterator p = this->segment_list_.begin();
2257 p != this->segment_list_.end();
2260 if ((*p)->type() == elfcpp::PT_LOAD
2261 && ((*p)->flags() & elfcpp::PF_R) != 0
2262 && (parameters->options().omagic()
2263 || ((*p)->flags() & elfcpp::PF_W) == 0)
2264 && (!target->isolate_execinstr()
2265 || ((*p)->flags() & elfcpp::PF_X) == 0))
2267 if (best == NULL || this->segment_precedes(*p, best))
2274 gold_assert(!this->script_options_->saw_phdrs_clause());
2276 Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
2281 // Save states of all current output segments. Store saved states
2282 // in SEGMENT_STATES.
2285 Layout::save_segments(Segment_states* segment_states)
2287 for (Segment_list::const_iterator p = this->segment_list_.begin();
2288 p != this->segment_list_.end();
2291 Output_segment* segment = *p;
2293 Output_segment* copy = new Output_segment(*segment);
2294 (*segment_states)[segment] = copy;
2298 // Restore states of output segments and delete any segment not found in
2302 Layout::restore_segments(const Segment_states* segment_states)
2304 // Go through the segment list and remove any segment added in the
2306 this->tls_segment_ = NULL;
2307 this->relro_segment_ = NULL;
2308 Segment_list::iterator list_iter = this->segment_list_.begin();
2309 while (list_iter != this->segment_list_.end())
2311 Output_segment* segment = *list_iter;
2312 Segment_states::const_iterator states_iter =
2313 segment_states->find(segment);
2314 if (states_iter != segment_states->end())
2316 const Output_segment* copy = states_iter->second;
2317 // Shallow copy to restore states.
2320 // Also fix up TLS and RELRO segment pointers as appropriate.
2321 if (segment->type() == elfcpp::PT_TLS)
2322 this->tls_segment_ = segment;
2323 else if (segment->type() == elfcpp::PT_GNU_RELRO)
2324 this->relro_segment_ = segment;
2330 list_iter = this->segment_list_.erase(list_iter);
2331 // This is a segment created during section layout. It should be
2332 // safe to remove it since we should have removed all pointers to it.
2338 // Clean up after relaxation so that sections can be laid out again.
2341 Layout::clean_up_after_relaxation()
2343 // Restore the segments to point state just prior to the relaxation loop.
2344 Script_sections* script_section = this->script_options_->script_sections();
2345 script_section->release_segments();
2346 this->restore_segments(this->segment_states_);
2348 // Reset section addresses and file offsets
2349 for (Section_list::iterator p = this->section_list_.begin();
2350 p != this->section_list_.end();
2353 (*p)->restore_states();
2355 // If an input section changes size because of relaxation,
2356 // we need to adjust the section offsets of all input sections.
2357 // after such a section.
2358 if ((*p)->section_offsets_need_adjustment())
2359 (*p)->adjust_section_offsets();
2361 (*p)->reset_address_and_file_offset();
2364 // Reset special output object address and file offsets.
2365 for (Data_list::iterator p = this->special_output_list_.begin();
2366 p != this->special_output_list_.end();
2368 (*p)->reset_address_and_file_offset();
2370 // A linker script may have created some output section data objects.
2371 // They are useless now.
2372 for (Output_section_data_list::const_iterator p =
2373 this->script_output_section_data_list_.begin();
2374 p != this->script_output_section_data_list_.end();
2377 this->script_output_section_data_list_.clear();
2379 // Special-case fill output objects are recreated each time through
2380 // the relaxation loop.
2381 this->reset_relax_output();
2385 Layout::reset_relax_output()
2387 for (Data_list::const_iterator p = this->relax_output_list_.begin();
2388 p != this->relax_output_list_.end();
2391 this->relax_output_list_.clear();
2394 // Prepare for relaxation.
2397 Layout::prepare_for_relaxation()
2399 // Create an relaxation debug check if in debugging mode.
2400 if (is_debugging_enabled(DEBUG_RELAXATION))
2401 this->relaxation_debug_check_ = new Relaxation_debug_check();
2403 // Save segment states.
2404 this->segment_states_ = new Segment_states();
2405 this->save_segments(this->segment_states_);
2407 for(Section_list::const_iterator p = this->section_list_.begin();
2408 p != this->section_list_.end();
2410 (*p)->save_states();
2412 if (is_debugging_enabled(DEBUG_RELAXATION))
2413 this->relaxation_debug_check_->check_output_data_for_reset_values(
2414 this->section_list_, this->special_output_list_,
2415 this->relax_output_list_);
2417 // Also enable recording of output section data from scripts.
2418 this->record_output_section_data_from_script_ = true;
2421 // If the user set the address of the text segment, that may not be
2422 // compatible with putting the segment headers and file headers into
2423 // that segment. For isolate_execinstr() targets, it's the rodata
2424 // segment rather than text where we might put the headers.
2426 load_seg_unusable_for_headers(const Target* target)
2428 const General_options& options = parameters->options();
2429 if (target->isolate_execinstr())
2430 return (options.user_set_Trodata_segment()
2431 && options.Trodata_segment() % target->abi_pagesize() != 0);
2433 return (options.user_set_Ttext()
2434 && options.Ttext() % target->abi_pagesize() != 0);
2437 // Relaxation loop body: If target has no relaxation, this runs only once
2438 // Otherwise, the target relaxation hook is called at the end of
2439 // each iteration. If the hook returns true, it means re-layout of
2440 // section is required.
2442 // The number of segments created by a linking script without a PHDRS
2443 // clause may be affected by section sizes and alignments. There is
2444 // a remote chance that relaxation causes different number of PT_LOAD
2445 // segments are created and sections are attached to different segments.
2446 // Therefore, we always throw away all segments created during section
2447 // layout. In order to be able to restart the section layout, we keep
2448 // a copy of the segment list right before the relaxation loop and use
2449 // that to restore the segments.
2451 // PASS is the current relaxation pass number.
2452 // SYMTAB is a symbol table.
2453 // PLOAD_SEG is the address of a pointer for the load segment.
2454 // PHDR_SEG is a pointer to the PHDR segment.
2455 // SEGMENT_HEADERS points to the output segment header.
2456 // FILE_HEADER points to the output file header.
2457 // PSHNDX is the address to store the output section index.
2460 Layout::relaxation_loop_body(
2463 Symbol_table* symtab,
2464 Output_segment** pload_seg,
2465 Output_segment* phdr_seg,
2466 Output_segment_headers* segment_headers,
2467 Output_file_header* file_header,
2468 unsigned int* pshndx)
2470 // If this is not the first iteration, we need to clean up after
2471 // relaxation so that we can lay out the sections again.
2473 this->clean_up_after_relaxation();
2475 // If there is a SECTIONS clause, put all the input sections into
2476 // the required order.
2477 Output_segment* load_seg;
2478 if (this->script_options_->saw_sections_clause())
2479 load_seg = this->set_section_addresses_from_script(symtab);
2480 else if (parameters->options().relocatable())
2483 load_seg = this->find_first_load_seg(target);
2485 if (parameters->options().oformat_enum()
2486 != General_options::OBJECT_FORMAT_ELF)
2489 if (load_seg_unusable_for_headers(target))
2495 gold_assert(phdr_seg == NULL
2497 || this->script_options_->saw_sections_clause());
2499 // If the address of the load segment we found has been set by
2500 // --section-start rather than by a script, then adjust the VMA and
2501 // LMA downward if possible to include the file and section headers.
2502 uint64_t header_gap = 0;
2503 if (load_seg != NULL
2504 && load_seg->are_addresses_set()
2505 && !this->script_options_->saw_sections_clause()
2506 && !parameters->options().relocatable())
2508 file_header->finalize_data_size();
2509 segment_headers->finalize_data_size();
2510 size_t sizeof_headers = (file_header->data_size()
2511 + segment_headers->data_size());
2512 const uint64_t abi_pagesize = target->abi_pagesize();
2513 uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers;
2514 hdr_paddr &= ~(abi_pagesize - 1);
2515 uint64_t subtract = load_seg->paddr() - hdr_paddr;
2516 if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract)
2520 load_seg->set_addresses(load_seg->vaddr() - subtract,
2521 load_seg->paddr() - subtract);
2522 header_gap = subtract - sizeof_headers;
2526 // Lay out the segment headers.
2527 if (!parameters->options().relocatable())
2529 gold_assert(segment_headers != NULL);
2530 if (header_gap != 0 && load_seg != NULL)
2532 Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1);
2533 load_seg->add_initial_output_data(z);
2535 if (load_seg != NULL)
2536 load_seg->add_initial_output_data(segment_headers);
2537 if (phdr_seg != NULL)
2538 phdr_seg->add_initial_output_data(segment_headers);
2541 // Lay out the file header.
2542 if (load_seg != NULL)
2543 load_seg->add_initial_output_data(file_header);
2545 if (this->script_options_->saw_phdrs_clause()
2546 && !parameters->options().relocatable())
2548 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2549 // clause in a linker script.
2550 Script_sections* ss = this->script_options_->script_sections();
2551 ss->put_headers_in_phdrs(file_header, segment_headers);
2554 // We set the output section indexes in set_segment_offsets and
2555 // set_section_indexes.
2558 // Set the file offsets of all the segments, and all the sections
2561 if (!parameters->options().relocatable())
2562 off = this->set_segment_offsets(target, load_seg, pshndx);
2564 off = this->set_relocatable_section_offsets(file_header, pshndx);
2566 // Verify that the dummy relaxation does not change anything.
2567 if (is_debugging_enabled(DEBUG_RELAXATION))
2570 this->relaxation_debug_check_->read_sections(this->section_list_);
2572 this->relaxation_debug_check_->verify_sections(this->section_list_);
2575 *pload_seg = load_seg;
2579 // Search the list of patterns and find the postion of the given section
2580 // name in the output section. If the section name matches a glob
2581 // pattern and a non-glob name, then the non-glob position takes
2582 // precedence. Return 0 if no match is found.
2585 Layout::find_section_order_index(const std::string& section_name)
2587 Unordered_map<std::string, unsigned int>::iterator map_it;
2588 map_it = this->input_section_position_.find(section_name);
2589 if (map_it != this->input_section_position_.end())
2590 return map_it->second;
2592 // Absolute match failed. Linear search the glob patterns.
2593 std::vector<std::string>::iterator it;
2594 for (it = this->input_section_glob_.begin();
2595 it != this->input_section_glob_.end();
2598 if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0)
2600 map_it = this->input_section_position_.find(*it);
2601 gold_assert(map_it != this->input_section_position_.end());
2602 return map_it->second;
2608 // Read the sequence of input sections from the file specified with
2609 // option --section-ordering-file.
2612 Layout::read_layout_from_file()
2614 const char* filename = parameters->options().section_ordering_file();
2620 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2621 filename, strerror(errno));
2623 std::getline(in, line); // this chops off the trailing \n, if any
2624 unsigned int position = 1;
2625 this->set_section_ordering_specified();
2629 if (!line.empty() && line[line.length() - 1] == '\r') // Windows
2630 line.resize(line.length() - 1);
2631 // Ignore comments, beginning with '#'
2634 std::getline(in, line);
2637 this->input_section_position_[line] = position;
2638 // Store all glob patterns in a vector.
2639 if (is_wildcard_string(line.c_str()))
2640 this->input_section_glob_.push_back(line);
2642 std::getline(in, line);
2646 // Finalize the layout. When this is called, we have created all the
2647 // output sections and all the output segments which are based on
2648 // input sections. We have several things to do, and we have to do
2649 // them in the right order, so that we get the right results correctly
2652 // 1) Finalize the list of output segments and create the segment
2655 // 2) Finalize the dynamic symbol table and associated sections.
2657 // 3) Determine the final file offset of all the output segments.
2659 // 4) Determine the final file offset of all the SHF_ALLOC output
2662 // 5) Create the symbol table sections and the section name table
2665 // 6) Finalize the symbol table: set symbol values to their final
2666 // value and make a final determination of which symbols are going
2667 // into the output symbol table.
2669 // 7) Create the section table header.
2671 // 8) Determine the final file offset of all the output sections which
2672 // are not SHF_ALLOC, including the section table header.
2674 // 9) Finalize the ELF file header.
2676 // This function returns the size of the output file.
2679 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
2680 Target* target, const Task* task)
2682 target->finalize_sections(this, input_objects, symtab);
2684 this->count_local_symbols(task, input_objects);
2686 this->link_stabs_sections();
2688 Output_segment* phdr_seg = NULL;
2689 if (!parameters->options().relocatable() && !parameters->doing_static_link())
2691 // There was a dynamic object in the link. We need to create
2692 // some information for the dynamic linker.
2694 // Create the PT_PHDR segment which will hold the program
2696 if (!this->script_options_->saw_phdrs_clause())
2697 phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
2699 // Create the dynamic symbol table, including the hash table.
2700 Output_section* dynstr;
2701 std::vector<Symbol*> dynamic_symbols;
2702 unsigned int local_dynamic_count;
2703 Versions versions(*this->script_options()->version_script_info(),
2705 this->create_dynamic_symtab(input_objects, symtab, &dynstr,
2706 &local_dynamic_count, &dynamic_symbols,
2709 // Create the .interp section to hold the name of the
2710 // interpreter, and put it in a PT_INTERP segment. Don't do it
2711 // if we saw a .interp section in an input file.
2712 if ((!parameters->options().shared()
2713 || parameters->options().dynamic_linker() != NULL)
2714 && this->interp_segment_ == NULL)
2715 this->create_interp(target);
2717 // Finish the .dynamic section to hold the dynamic data, and put
2718 // it in a PT_DYNAMIC segment.
2719 this->finish_dynamic_section(input_objects, symtab);
2721 // We should have added everything we need to the dynamic string
2723 this->dynpool_.set_string_offsets();
2725 // Create the version sections. We can't do this until the
2726 // dynamic string table is complete.
2727 this->create_version_sections(&versions, symtab, local_dynamic_count,
2728 dynamic_symbols, dynstr);
2730 // Set the size of the _DYNAMIC symbol. We can't do this until
2731 // after we call create_version_sections.
2732 this->set_dynamic_symbol_size(symtab);
2735 // Create segment headers.
2736 Output_segment_headers* segment_headers =
2737 (parameters->options().relocatable()
2739 : new Output_segment_headers(this->segment_list_));
2741 // Lay out the file header.
2742 Output_file_header* file_header = new Output_file_header(target, symtab,
2745 this->special_output_list_.push_back(file_header);
2746 if (segment_headers != NULL)
2747 this->special_output_list_.push_back(segment_headers);
2749 // Find approriate places for orphan output sections if we are using
2751 if (this->script_options_->saw_sections_clause())
2752 this->place_orphan_sections_in_script();
2754 Output_segment* load_seg;
2759 // Take a snapshot of the section layout as needed.
2760 if (target->may_relax())
2761 this->prepare_for_relaxation();
2763 // Run the relaxation loop to lay out sections.
2766 off = this->relaxation_loop_body(pass, target, symtab, &load_seg,
2767 phdr_seg, segment_headers, file_header,
2771 while (target->may_relax()
2772 && target->relax(pass, input_objects, symtab, this, task));
2774 // If there is a load segment that contains the file and program headers,
2775 // provide a symbol __ehdr_start pointing there.
2776 // A program can use this to examine itself robustly.
2777 Symbol *ehdr_start = symtab->lookup("__ehdr_start");
2778 if (ehdr_start != NULL && ehdr_start->is_predefined())
2780 if (load_seg != NULL)
2781 ehdr_start->set_output_segment(load_seg, Symbol::SEGMENT_START);
2783 ehdr_start->set_undefined();
2786 // Set the file offsets of all the non-data sections we've seen so
2787 // far which don't have to wait for the input sections. We need
2788 // this in order to finalize local symbols in non-allocated
2790 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2792 // Set the section indexes of all unallocated sections seen so far,
2793 // in case any of them are somehow referenced by a symbol.
2794 shndx = this->set_section_indexes(shndx);
2796 // Create the symbol table sections.
2797 this->create_symtab_sections(input_objects, symtab, shndx, &off);
2798 if (!parameters->doing_static_link())
2799 this->assign_local_dynsym_offsets(input_objects);
2801 // Process any symbol assignments from a linker script. This must
2802 // be called after the symbol table has been finalized.
2803 this->script_options_->finalize_symbols(symtab, this);
2805 // Create the incremental inputs sections.
2806 if (this->incremental_inputs_)
2808 this->incremental_inputs_->finalize();
2809 this->create_incremental_info_sections(symtab);
2812 // Create the .shstrtab section.
2813 Output_section* shstrtab_section = this->create_shstrtab();
2815 // Set the file offsets of the rest of the non-data sections which
2816 // don't have to wait for the input sections.
2817 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2819 // Now that all sections have been created, set the section indexes
2820 // for any sections which haven't been done yet.
2821 shndx = this->set_section_indexes(shndx);
2823 // Create the section table header.
2824 this->create_shdrs(shstrtab_section, &off);
2826 // If there are no sections which require postprocessing, we can
2827 // handle the section names now, and avoid a resize later.
2828 if (!this->any_postprocessing_sections_)
2830 off = this->set_section_offsets(off,
2831 POSTPROCESSING_SECTIONS_PASS);
2833 this->set_section_offsets(off,
2834 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
2837 file_header->set_section_info(this->section_headers_, shstrtab_section);
2839 // Now we know exactly where everything goes in the output file
2840 // (except for non-allocated sections which require postprocessing).
2841 Output_data::layout_complete();
2843 this->output_file_size_ = off;
2848 // Create a note header following the format defined in the ELF ABI.
2849 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2850 // of the section to create, DESCSZ is the size of the descriptor.
2851 // ALLOCATE is true if the section should be allocated in memory.
2852 // This returns the new note section. It sets *TRAILING_PADDING to
2853 // the number of trailing zero bytes required.
2856 Layout::create_note(const char* name, int note_type,
2857 const char* section_name, size_t descsz,
2858 bool allocate, size_t* trailing_padding)
2860 // Authorities all agree that the values in a .note field should
2861 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2862 // they differ on what the alignment is for 64-bit binaries.
2863 // The GABI says unambiguously they take 8-byte alignment:
2864 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2865 // Other documentation says alignment should always be 4 bytes:
2866 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2867 // GNU ld and GNU readelf both support the latter (at least as of
2868 // version 2.16.91), and glibc always generates the latter for
2869 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2871 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2872 const int size = parameters->target().get_size();
2874 const int size = 32;
2877 // The contents of the .note section.
2878 size_t namesz = strlen(name) + 1;
2879 size_t aligned_namesz = align_address(namesz, size / 8);
2880 size_t aligned_descsz = align_address(descsz, size / 8);
2882 size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
2884 unsigned char* buffer = new unsigned char[notehdrsz];
2885 memset(buffer, 0, notehdrsz);
2887 bool is_big_endian = parameters->target().is_big_endian();
2893 elfcpp::Swap<32, false>::writeval(buffer, namesz);
2894 elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
2895 elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
2899 elfcpp::Swap<32, true>::writeval(buffer, namesz);
2900 elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
2901 elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
2904 else if (size == 64)
2908 elfcpp::Swap<64, false>::writeval(buffer, namesz);
2909 elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
2910 elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
2914 elfcpp::Swap<64, true>::writeval(buffer, namesz);
2915 elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
2916 elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
2922 memcpy(buffer + 3 * (size / 8), name, namesz);
2924 elfcpp::Elf_Xword flags = 0;
2925 Output_section_order order = ORDER_INVALID;
2928 flags = elfcpp::SHF_ALLOC;
2929 order = ORDER_RO_NOTE;
2931 Output_section* os = this->choose_output_section(NULL, section_name,
2933 flags, false, order, false);
2937 Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
2940 os->add_output_section_data(posd);
2942 *trailing_padding = aligned_descsz - descsz;
2947 // For an executable or shared library, create a note to record the
2948 // version of gold used to create the binary.
2951 Layout::create_gold_note()
2953 if (parameters->options().relocatable()
2954 || parameters->incremental_update())
2957 std::string desc = std::string("gold ") + gold::get_version_string();
2959 size_t trailing_padding;
2960 Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
2961 ".note.gnu.gold-version", desc.size(),
2962 false, &trailing_padding);
2966 Output_section_data* posd = new Output_data_const(desc, 4);
2967 os->add_output_section_data(posd);
2969 if (trailing_padding > 0)
2971 posd = new Output_data_zero_fill(trailing_padding, 0);
2972 os->add_output_section_data(posd);
2976 // Record whether the stack should be executable. This can be set
2977 // from the command line using the -z execstack or -z noexecstack
2978 // options. Otherwise, if any input file has a .note.GNU-stack
2979 // section with the SHF_EXECINSTR flag set, the stack should be
2980 // executable. Otherwise, if at least one input file a
2981 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2982 // section, we use the target default for whether the stack should be
2983 // executable. Otherwise, we don't generate a stack note. When
2984 // generating a object file, we create a .note.GNU-stack section with
2985 // the appropriate marking. When generating an executable or shared
2986 // library, we create a PT_GNU_STACK segment.
2989 Layout::create_executable_stack_info()
2991 bool is_stack_executable;
2992 if (parameters->options().is_execstack_set())
2994 is_stack_executable = parameters->options().is_stack_executable();
2995 if (!is_stack_executable
2996 && this->input_requires_executable_stack_
2997 && parameters->options().warn_execstack())
2998 gold_warning(_("one or more inputs require executable stack, "
2999 "but -z noexecstack was given"));
3001 else if (!this->input_with_gnu_stack_note_)
3005 if (this->input_requires_executable_stack_)
3006 is_stack_executable = true;
3007 else if (this->input_without_gnu_stack_note_)
3008 is_stack_executable =
3009 parameters->target().is_default_stack_executable();
3011 is_stack_executable = false;
3014 if (parameters->options().relocatable())
3016 const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
3017 elfcpp::Elf_Xword flags = 0;
3018 if (is_stack_executable)
3019 flags |= elfcpp::SHF_EXECINSTR;
3020 this->make_output_section(name, elfcpp::SHT_PROGBITS, flags,
3021 ORDER_INVALID, false);
3025 if (this->script_options_->saw_phdrs_clause())
3027 int flags = elfcpp::PF_R | elfcpp::PF_W;
3028 if (is_stack_executable)
3029 flags |= elfcpp::PF_X;
3030 this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
3034 // If --build-id was used, set up the build ID note.
3037 Layout::create_build_id()
3039 if (!parameters->options().user_set_build_id())
3042 const char* style = parameters->options().build_id();
3043 if (strcmp(style, "none") == 0)
3046 // Set DESCSZ to the size of the note descriptor. When possible,
3047 // set DESC to the note descriptor contents.
3050 if (strcmp(style, "md5") == 0)
3052 else if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0))
3054 else if (strcmp(style, "uuid") == 0)
3056 const size_t uuidsz = 128 / 8;
3058 char buffer[uuidsz];
3059 memset(buffer, 0, uuidsz);
3061 int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
3063 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
3067 ssize_t got = ::read(descriptor, buffer, uuidsz);
3068 release_descriptor(descriptor, true);
3070 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
3071 else if (static_cast<size_t>(got) != uuidsz)
3072 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
3076 desc.assign(buffer, uuidsz);
3079 else if (strncmp(style, "0x", 2) == 0)
3082 const char* p = style + 2;
3085 if (hex_p(p[0]) && hex_p(p[1]))
3087 char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
3091 else if (*p == '-' || *p == ':')
3094 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
3097 descsz = desc.size();
3100 gold_fatal(_("unrecognized --build-id argument '%s'"), style);
3103 size_t trailing_padding;
3104 Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
3105 ".note.gnu.build-id", descsz, true,
3112 // We know the value already, so we fill it in now.
3113 gold_assert(desc.size() == descsz);
3115 Output_section_data* posd = new Output_data_const(desc, 4);
3116 os->add_output_section_data(posd);
3118 if (trailing_padding != 0)
3120 posd = new Output_data_zero_fill(trailing_padding, 0);
3121 os->add_output_section_data(posd);
3126 // We need to compute a checksum after we have completed the
3128 gold_assert(trailing_padding == 0);
3129 this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
3130 os->add_output_section_data(this->build_id_note_);
3134 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3135 // field of the former should point to the latter. I'm not sure who
3136 // started this, but the GNU linker does it, and some tools depend
3140 Layout::link_stabs_sections()
3142 if (!this->have_stabstr_section_)
3145 for (Section_list::iterator p = this->section_list_.begin();
3146 p != this->section_list_.end();
3149 if ((*p)->type() != elfcpp::SHT_STRTAB)
3152 const char* name = (*p)->name();
3153 if (strncmp(name, ".stab", 5) != 0)
3156 size_t len = strlen(name);
3157 if (strcmp(name + len - 3, "str") != 0)
3160 std::string stab_name(name, len - 3);
3161 Output_section* stab_sec;
3162 stab_sec = this->find_output_section(stab_name.c_str());
3163 if (stab_sec != NULL)
3164 stab_sec->set_link_section(*p);
3168 // Create .gnu_incremental_inputs and related sections needed
3169 // for the next run of incremental linking to check what has changed.
3172 Layout::create_incremental_info_sections(Symbol_table* symtab)
3174 Incremental_inputs* incr = this->incremental_inputs_;
3176 gold_assert(incr != NULL);
3178 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3179 incr->create_data_sections(symtab);
3181 // Add the .gnu_incremental_inputs section.
3182 const char* incremental_inputs_name =
3183 this->namepool_.add(".gnu_incremental_inputs", false, NULL);
3184 Output_section* incremental_inputs_os =
3185 this->make_output_section(incremental_inputs_name,
3186 elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0,
3187 ORDER_INVALID, false);
3188 incremental_inputs_os->add_output_section_data(incr->inputs_section());
3190 // Add the .gnu_incremental_symtab section.
3191 const char* incremental_symtab_name =
3192 this->namepool_.add(".gnu_incremental_symtab", false, NULL);
3193 Output_section* incremental_symtab_os =
3194 this->make_output_section(incremental_symtab_name,
3195 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0,
3196 ORDER_INVALID, false);
3197 incremental_symtab_os->add_output_section_data(incr->symtab_section());
3198 incremental_symtab_os->set_entsize(4);
3200 // Add the .gnu_incremental_relocs section.
3201 const char* incremental_relocs_name =
3202 this->namepool_.add(".gnu_incremental_relocs", false, NULL);
3203 Output_section* incremental_relocs_os =
3204 this->make_output_section(incremental_relocs_name,
3205 elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0,
3206 ORDER_INVALID, false);
3207 incremental_relocs_os->add_output_section_data(incr->relocs_section());
3208 incremental_relocs_os->set_entsize(incr->relocs_entsize());
3210 // Add the .gnu_incremental_got_plt section.
3211 const char* incremental_got_plt_name =
3212 this->namepool_.add(".gnu_incremental_got_plt", false, NULL);
3213 Output_section* incremental_got_plt_os =
3214 this->make_output_section(incremental_got_plt_name,
3215 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0,
3216 ORDER_INVALID, false);
3217 incremental_got_plt_os->add_output_section_data(incr->got_plt_section());
3219 // Add the .gnu_incremental_strtab section.
3220 const char* incremental_strtab_name =
3221 this->namepool_.add(".gnu_incremental_strtab", false, NULL);
3222 Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name,
3223 elfcpp::SHT_STRTAB, 0,
3224 ORDER_INVALID, false);
3225 Output_data_strtab* strtab_data =
3226 new Output_data_strtab(incr->get_stringpool());
3227 incremental_strtab_os->add_output_section_data(strtab_data);
3229 incremental_inputs_os->set_after_input_sections();
3230 incremental_symtab_os->set_after_input_sections();
3231 incremental_relocs_os->set_after_input_sections();
3232 incremental_got_plt_os->set_after_input_sections();
3234 incremental_inputs_os->set_link_section(incremental_strtab_os);
3235 incremental_symtab_os->set_link_section(incremental_inputs_os);
3236 incremental_relocs_os->set_link_section(incremental_inputs_os);
3237 incremental_got_plt_os->set_link_section(incremental_inputs_os);
3240 // Return whether SEG1 should be before SEG2 in the output file. This
3241 // is based entirely on the segment type and flags. When this is
3242 // called the segment addresses have normally not yet been set.
3245 Layout::segment_precedes(const Output_segment* seg1,
3246 const Output_segment* seg2)
3248 elfcpp::Elf_Word type1 = seg1->type();
3249 elfcpp::Elf_Word type2 = seg2->type();
3251 // The single PT_PHDR segment is required to precede any loadable
3252 // segment. We simply make it always first.
3253 if (type1 == elfcpp::PT_PHDR)
3255 gold_assert(type2 != elfcpp::PT_PHDR);
3258 if (type2 == elfcpp::PT_PHDR)
3261 // The single PT_INTERP segment is required to precede any loadable
3262 // segment. We simply make it always second.
3263 if (type1 == elfcpp::PT_INTERP)
3265 gold_assert(type2 != elfcpp::PT_INTERP);
3268 if (type2 == elfcpp::PT_INTERP)
3271 // We then put PT_LOAD segments before any other segments.
3272 if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
3274 if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
3277 // We put the PT_TLS segment last except for the PT_GNU_RELRO
3278 // segment, because that is where the dynamic linker expects to find
3279 // it (this is just for efficiency; other positions would also work
3281 if (type1 == elfcpp::PT_TLS
3282 && type2 != elfcpp::PT_TLS
3283 && type2 != elfcpp::PT_GNU_RELRO)
3285 if (type2 == elfcpp::PT_TLS
3286 && type1 != elfcpp::PT_TLS
3287 && type1 != elfcpp::PT_GNU_RELRO)
3290 // We put the PT_GNU_RELRO segment last, because that is where the
3291 // dynamic linker expects to find it (as with PT_TLS, this is just
3293 if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
3295 if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
3298 const elfcpp::Elf_Word flags1 = seg1->flags();
3299 const elfcpp::Elf_Word flags2 = seg2->flags();
3301 // The order of non-PT_LOAD segments is unimportant. We simply sort
3302 // by the numeric segment type and flags values. There should not
3303 // be more than one segment with the same type and flags, except
3304 // when a linker script specifies such.
3305 if (type1 != elfcpp::PT_LOAD)
3308 return type1 < type2;
3309 gold_assert(flags1 != flags2
3310 || this->script_options_->saw_phdrs_clause());
3311 return flags1 < flags2;
3314 // If the addresses are set already, sort by load address.
3315 if (seg1->are_addresses_set())
3317 if (!seg2->are_addresses_set())
3320 unsigned int section_count1 = seg1->output_section_count();
3321 unsigned int section_count2 = seg2->output_section_count();
3322 if (section_count1 == 0 && section_count2 > 0)
3324 if (section_count1 > 0 && section_count2 == 0)
3327 uint64_t paddr1 = (seg1->are_addresses_set()
3329 : seg1->first_section_load_address());
3330 uint64_t paddr2 = (seg2->are_addresses_set()
3332 : seg2->first_section_load_address());
3334 if (paddr1 != paddr2)
3335 return paddr1 < paddr2;
3337 else if (seg2->are_addresses_set())
3340 // A segment which holds large data comes after a segment which does
3341 // not hold large data.
3342 if (seg1->is_large_data_segment())
3344 if (!seg2->is_large_data_segment())
3347 else if (seg2->is_large_data_segment())
3350 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
3351 // segments come before writable segments. Then writable segments
3352 // with data come before writable segments without data. Then
3353 // executable segments come before non-executable segments. Then
3354 // the unlikely case of a non-readable segment comes before the
3355 // normal case of a readable segment. If there are multiple
3356 // segments with the same type and flags, we require that the
3357 // address be set, and we sort by virtual address and then physical
3359 if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
3360 return (flags1 & elfcpp::PF_W) == 0;
3361 if ((flags1 & elfcpp::PF_W) != 0
3362 && seg1->has_any_data_sections() != seg2->has_any_data_sections())
3363 return seg1->has_any_data_sections();
3364 if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
3365 return (flags1 & elfcpp::PF_X) != 0;
3366 if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
3367 return (flags1 & elfcpp::PF_R) == 0;
3369 // We shouldn't get here--we shouldn't create segments which we
3370 // can't distinguish. Unless of course we are using a weird linker
3371 // script or overlapping --section-start options. We could also get
3372 // here if plugins want unique segments for subsets of sections.
3373 gold_assert(this->script_options_->saw_phdrs_clause()
3374 || parameters->options().any_section_start()
3375 || this->is_unique_segment_for_sections_specified());
3379 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3382 align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
3384 uint64_t unsigned_off = off;
3385 uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
3386 | (addr & (abi_pagesize - 1)));
3387 if (aligned_off < unsigned_off)
3388 aligned_off += abi_pagesize;
3392 // On targets where the text segment contains only executable code,
3393 // a non-executable segment is never the text segment.
3396 is_text_segment(const Target* target, const Output_segment* seg)
3398 elfcpp::Elf_Xword flags = seg->flags();
3399 if ((flags & elfcpp::PF_W) != 0)
3401 if ((flags & elfcpp::PF_X) == 0)
3402 return !target->isolate_execinstr();
3406 // Set the file offsets of all the segments, and all the sections they
3407 // contain. They have all been created. LOAD_SEG must be be laid out
3408 // first. Return the offset of the data to follow.
3411 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
3412 unsigned int* pshndx)
3414 // Sort them into the final order. We use a stable sort so that we
3415 // don't randomize the order of indistinguishable segments created
3416 // by linker scripts.
3417 std::stable_sort(this->segment_list_.begin(), this->segment_list_.end(),
3418 Layout::Compare_segments(this));
3420 // Find the PT_LOAD segments, and set their addresses and offsets
3421 // and their section's addresses and offsets.
3422 uint64_t start_addr;
3423 if (parameters->options().user_set_Ttext())
3424 start_addr = parameters->options().Ttext();
3425 else if (parameters->options().output_is_position_independent())
3428 start_addr = target->default_text_segment_address();
3430 uint64_t addr = start_addr;
3433 // If LOAD_SEG is NULL, then the file header and segment headers
3434 // will not be loadable. But they still need to be at offset 0 in
3435 // the file. Set their offsets now.
3436 if (load_seg == NULL)
3438 for (Data_list::iterator p = this->special_output_list_.begin();
3439 p != this->special_output_list_.end();
3442 off = align_address(off, (*p)->addralign());
3443 (*p)->set_address_and_file_offset(0, off);
3444 off += (*p)->data_size();
3448 unsigned int increase_relro = this->increase_relro_;
3449 if (this->script_options_->saw_sections_clause())
3452 const bool check_sections = parameters->options().check_sections();
3453 Output_segment* last_load_segment = NULL;
3455 unsigned int shndx_begin = *pshndx;
3456 unsigned int shndx_load_seg = *pshndx;
3458 for (Segment_list::iterator p = this->segment_list_.begin();
3459 p != this->segment_list_.end();
3462 if ((*p)->type() == elfcpp::PT_LOAD)
3464 if (target->isolate_execinstr())
3466 // When we hit the segment that should contain the
3467 // file headers, reset the file offset so we place
3468 // it and subsequent segments appropriately.
3469 // We'll fix up the preceding segments below.
3477 shndx_load_seg = *pshndx;
3483 // Verify that the file headers fall into the first segment.
3484 if (load_seg != NULL && load_seg != *p)
3489 bool are_addresses_set = (*p)->are_addresses_set();
3490 if (are_addresses_set)
3492 // When it comes to setting file offsets, we care about
3493 // the physical address.
3494 addr = (*p)->paddr();
3496 else if (parameters->options().user_set_Ttext()
3497 && (parameters->options().omagic()
3498 || is_text_segment(target, *p)))
3500 are_addresses_set = true;
3502 else if (parameters->options().user_set_Trodata_segment()
3503 && ((*p)->flags() & (elfcpp::PF_W | elfcpp::PF_X)) == 0)
3505 addr = parameters->options().Trodata_segment();
3506 are_addresses_set = true;
3508 else if (parameters->options().user_set_Tdata()
3509 && ((*p)->flags() & elfcpp::PF_W) != 0
3510 && (!parameters->options().user_set_Tbss()
3511 || (*p)->has_any_data_sections()))
3513 addr = parameters->options().Tdata();
3514 are_addresses_set = true;
3516 else if (parameters->options().user_set_Tbss()
3517 && ((*p)->flags() & elfcpp::PF_W) != 0
3518 && !(*p)->has_any_data_sections())
3520 addr = parameters->options().Tbss();
3521 are_addresses_set = true;
3524 uint64_t orig_addr = addr;
3525 uint64_t orig_off = off;
3527 uint64_t aligned_addr = 0;
3528 uint64_t abi_pagesize = target->abi_pagesize();
3529 uint64_t common_pagesize = target->common_pagesize();
3531 if (!parameters->options().nmagic()
3532 && !parameters->options().omagic())
3533 (*p)->set_minimum_p_align(abi_pagesize);
3535 if (!are_addresses_set)
3537 // Skip the address forward one page, maintaining the same
3538 // position within the page. This lets us store both segments
3539 // overlapping on a single page in the file, but the loader will
3540 // put them on different pages in memory. We will revisit this
3541 // decision once we know the size of the segment.
3543 uint64_t max_align = (*p)->maximum_alignment();
3544 if (max_align > abi_pagesize)
3545 addr = align_address(addr, max_align);
3546 aligned_addr = addr;
3550 // This is the segment that will contain the file
3551 // headers, so its offset will have to be exactly zero.
3552 gold_assert(orig_off == 0);
3554 // If the target wants a fixed minimum distance from the
3555 // text segment to the read-only segment, move up now.
3557 start_addr + (parameters->options().user_set_rosegment_gap()
3558 ? parameters->options().rosegment_gap()
3559 : target->rosegment_gap());
3560 if (addr < min_addr)
3563 // But this is not the first segment! To make its
3564 // address congruent with its offset, that address better
3565 // be aligned to the ABI-mandated page size.
3566 addr = align_address(addr, abi_pagesize);
3567 aligned_addr = addr;
3571 if ((addr & (abi_pagesize - 1)) != 0)
3572 addr = addr + abi_pagesize;
3574 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3578 if (!parameters->options().nmagic()
3579 && !parameters->options().omagic())
3581 // Here we are also taking care of the case when
3582 // the maximum segment alignment is larger than the page size.
3583 off = align_file_offset(off, addr,
3584 std::max(abi_pagesize,
3585 (*p)->maximum_alignment()));
3589 // This is -N or -n with a section script which prevents
3590 // us from using a load segment. We need to ensure that
3591 // the file offset is aligned to the alignment of the
3592 // segment. This is because the linker script
3593 // implicitly assumed a zero offset. If we don't align
3594 // here, then the alignment of the sections in the
3595 // linker script may not match the alignment of the
3596 // sections in the set_section_addresses call below,
3597 // causing an error about dot moving backward.
3598 off = align_address(off, (*p)->maximum_alignment());
3601 unsigned int shndx_hold = *pshndx;
3602 bool has_relro = false;
3603 uint64_t new_addr = (*p)->set_section_addresses(target, this,
3609 // Now that we know the size of this segment, we may be able
3610 // to save a page in memory, at the cost of wasting some
3611 // file space, by instead aligning to the start of a new
3612 // page. Here we use the real machine page size rather than
3613 // the ABI mandated page size. If the segment has been
3614 // aligned so that the relro data ends at a page boundary,
3615 // we do not try to realign it.
3617 if (!are_addresses_set
3619 && aligned_addr != addr
3620 && !parameters->incremental())
3622 uint64_t first_off = (common_pagesize
3624 & (common_pagesize - 1)));
3625 uint64_t last_off = new_addr & (common_pagesize - 1);
3628 && ((aligned_addr & ~ (common_pagesize - 1))
3629 != (new_addr & ~ (common_pagesize - 1)))
3630 && first_off + last_off <= common_pagesize)
3632 *pshndx = shndx_hold;
3633 addr = align_address(aligned_addr, common_pagesize);
3634 addr = align_address(addr, (*p)->maximum_alignment());
3635 if ((addr & (abi_pagesize - 1)) != 0)
3636 addr = addr + abi_pagesize;
3637 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3638 off = align_file_offset(off, addr, abi_pagesize);
3640 increase_relro = this->increase_relro_;
3641 if (this->script_options_->saw_sections_clause())
3645 new_addr = (*p)->set_section_addresses(target, this,
3655 // Implement --check-sections. We know that the segments
3656 // are sorted by LMA.
3657 if (check_sections && last_load_segment != NULL)
3659 gold_assert(last_load_segment->paddr() <= (*p)->paddr());
3660 if (last_load_segment->paddr() + last_load_segment->memsz()
3663 unsigned long long lb1 = last_load_segment->paddr();
3664 unsigned long long le1 = lb1 + last_load_segment->memsz();
3665 unsigned long long lb2 = (*p)->paddr();
3666 unsigned long long le2 = lb2 + (*p)->memsz();
3667 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3668 "[0x%llx -> 0x%llx]"),
3669 lb1, le1, lb2, le2);
3672 last_load_segment = *p;
3676 if (load_seg != NULL && target->isolate_execinstr())
3678 // Process the early segments again, setting their file offsets
3679 // so they land after the segments starting at LOAD_SEG.
3680 off = align_file_offset(off, 0, target->abi_pagesize());
3682 this->reset_relax_output();
3684 for (Segment_list::iterator p = this->segment_list_.begin();
3688 if ((*p)->type() == elfcpp::PT_LOAD)
3690 // We repeat the whole job of assigning addresses and
3691 // offsets, but we really only want to change the offsets and
3692 // must ensure that the addresses all come out the same as
3693 // they did the first time through.
3694 bool has_relro = false;
3695 const uint64_t old_addr = (*p)->vaddr();
3696 const uint64_t old_end = old_addr + (*p)->memsz();
3697 uint64_t new_addr = (*p)->set_section_addresses(target, this,
3703 gold_assert(new_addr == old_end);
3707 gold_assert(shndx_begin == shndx_load_seg);
3710 // Handle the non-PT_LOAD segments, setting their offsets from their
3711 // section's offsets.
3712 for (Segment_list::iterator p = this->segment_list_.begin();
3713 p != this->segment_list_.end();
3716 if ((*p)->type() != elfcpp::PT_LOAD)
3717 (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO
3722 // Set the TLS offsets for each section in the PT_TLS segment.
3723 if (this->tls_segment_ != NULL)
3724 this->tls_segment_->set_tls_offsets();
3729 // Set the offsets of all the allocated sections when doing a
3730 // relocatable link. This does the same jobs as set_segment_offsets,
3731 // only for a relocatable link.
3734 Layout::set_relocatable_section_offsets(Output_data* file_header,
3735 unsigned int* pshndx)
3739 file_header->set_address_and_file_offset(0, 0);
3740 off += file_header->data_size();
3742 for (Section_list::iterator p = this->section_list_.begin();
3743 p != this->section_list_.end();
3746 // We skip unallocated sections here, except that group sections
3747 // have to come first.
3748 if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
3749 && (*p)->type() != elfcpp::SHT_GROUP)
3752 off = align_address(off, (*p)->addralign());
3754 // The linker script might have set the address.
3755 if (!(*p)->is_address_valid())
3756 (*p)->set_address(0);
3757 (*p)->set_file_offset(off);
3758 (*p)->finalize_data_size();
3759 if ((*p)->type() != elfcpp::SHT_NOBITS)
3760 off += (*p)->data_size();
3762 (*p)->set_out_shndx(*pshndx);
3769 // Set the file offset of all the sections not associated with a
3773 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
3775 off_t startoff = off;
3778 for (Section_list::iterator p = this->unattached_section_list_.begin();
3779 p != this->unattached_section_list_.end();
3782 // The symtab section is handled in create_symtab_sections.
3783 if (*p == this->symtab_section_)
3786 // If we've already set the data size, don't set it again.
3787 if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
3790 if (pass == BEFORE_INPUT_SECTIONS_PASS
3791 && (*p)->requires_postprocessing())
3793 (*p)->create_postprocessing_buffer();
3794 this->any_postprocessing_sections_ = true;
3797 if (pass == BEFORE_INPUT_SECTIONS_PASS
3798 && (*p)->after_input_sections())
3800 else if (pass == POSTPROCESSING_SECTIONS_PASS
3801 && (!(*p)->after_input_sections()
3802 || (*p)->type() == elfcpp::SHT_STRTAB))
3804 else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3805 && (!(*p)->after_input_sections()
3806 || (*p)->type() != elfcpp::SHT_STRTAB))
3809 if (!parameters->incremental_update())
3811 off = align_address(off, (*p)->addralign());
3812 (*p)->set_file_offset(off);
3813 (*p)->finalize_data_size();
3817 // Incremental update: allocate file space from free list.
3818 (*p)->pre_finalize_data_size();
3819 off_t current_size = (*p)->current_data_size();
3820 off = this->allocate(current_size, (*p)->addralign(), startoff);
3823 if (is_debugging_enabled(DEBUG_INCREMENTAL))
3824 this->free_list_.dump();
3825 gold_assert((*p)->output_section() != NULL);
3826 gold_fallback(_("out of patch space for section %s; "
3827 "relink with --incremental-full"),
3828 (*p)->output_section()->name());
3830 (*p)->set_file_offset(off);
3831 (*p)->finalize_data_size();
3832 if ((*p)->data_size() > current_size)
3834 gold_assert((*p)->output_section() != NULL);
3835 gold_fallback(_("%s: section changed size; "
3836 "relink with --incremental-full"),
3837 (*p)->output_section()->name());
3839 gold_debug(DEBUG_INCREMENTAL,
3840 "set_section_offsets: %08lx %08lx %s",
3841 static_cast<long>(off),
3842 static_cast<long>((*p)->data_size()),
3843 ((*p)->output_section() != NULL
3844 ? (*p)->output_section()->name() : "(special)"));
3847 off += (*p)->data_size();
3851 // At this point the name must be set.
3852 if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
3853 this->namepool_.add((*p)->name(), false, NULL);
3858 // Set the section indexes of all the sections not associated with a
3862 Layout::set_section_indexes(unsigned int shndx)
3864 for (Section_list::iterator p = this->unattached_section_list_.begin();
3865 p != this->unattached_section_list_.end();
3868 if (!(*p)->has_out_shndx())
3870 (*p)->set_out_shndx(shndx);
3877 // Set the section addresses according to the linker script. This is
3878 // only called when we see a SECTIONS clause. This returns the
3879 // program segment which should hold the file header and segment
3880 // headers, if any. It will return NULL if they should not be in a
3884 Layout::set_section_addresses_from_script(Symbol_table* symtab)
3886 Script_sections* ss = this->script_options_->script_sections();
3887 gold_assert(ss->saw_sections_clause());
3888 return this->script_options_->set_section_addresses(symtab, this);
3891 // Place the orphan sections in the linker script.
3894 Layout::place_orphan_sections_in_script()
3896 Script_sections* ss = this->script_options_->script_sections();
3897 gold_assert(ss->saw_sections_clause());
3899 // Place each orphaned output section in the script.
3900 for (Section_list::iterator p = this->section_list_.begin();
3901 p != this->section_list_.end();
3904 if (!(*p)->found_in_sections_clause())
3905 ss->place_orphan(*p);
3909 // Count the local symbols in the regular symbol table and the dynamic
3910 // symbol table, and build the respective string pools.
3913 Layout::count_local_symbols(const Task* task,
3914 const Input_objects* input_objects)
3916 // First, figure out an upper bound on the number of symbols we'll
3917 // be inserting into each pool. This helps us create the pools with
3918 // the right size, to avoid unnecessary hashtable resizing.
3919 unsigned int symbol_count = 0;
3920 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3921 p != input_objects->relobj_end();
3923 symbol_count += (*p)->local_symbol_count();
3925 // Go from "upper bound" to "estimate." We overcount for two
3926 // reasons: we double-count symbols that occur in more than one
3927 // object file, and we count symbols that are dropped from the
3928 // output. Add it all together and assume we overcount by 100%.
3931 // We assume all symbols will go into both the sympool and dynpool.
3932 this->sympool_.reserve(symbol_count);
3933 this->dynpool_.reserve(symbol_count);
3935 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3936 p != input_objects->relobj_end();
3939 Task_lock_obj<Object> tlo(task, *p);
3940 (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
3944 // Create the symbol table sections. Here we also set the final
3945 // values of the symbols. At this point all the loadable sections are
3946 // fully laid out. SHNUM is the number of sections so far.
3949 Layout::create_symtab_sections(const Input_objects* input_objects,
3950 Symbol_table* symtab,
3956 if (parameters->target().get_size() == 32)
3958 symsize = elfcpp::Elf_sizes<32>::sym_size;
3961 else if (parameters->target().get_size() == 64)
3963 symsize = elfcpp::Elf_sizes<64>::sym_size;
3969 // Compute file offsets relative to the start of the symtab section.
3972 // Save space for the dummy symbol at the start of the section. We
3973 // never bother to write this out--it will just be left as zero.
3975 unsigned int local_symbol_index = 1;
3977 // Add STT_SECTION symbols for each Output section which needs one.
3978 for (Section_list::iterator p = this->section_list_.begin();
3979 p != this->section_list_.end();
3982 if (!(*p)->needs_symtab_index())
3983 (*p)->set_symtab_index(-1U);
3986 (*p)->set_symtab_index(local_symbol_index);
3987 ++local_symbol_index;
3992 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3993 p != input_objects->relobj_end();
3996 unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
3998 off += (index - local_symbol_index) * symsize;
3999 local_symbol_index = index;
4002 unsigned int local_symcount = local_symbol_index;
4003 gold_assert(static_cast<off_t>(local_symcount * symsize) == off);
4006 size_t dyn_global_index;
4008 if (this->dynsym_section_ == NULL)
4011 dyn_global_index = 0;
4016 dyn_global_index = this->dynsym_section_->info();
4017 off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
4018 dynoff = this->dynsym_section_->offset() + locsize;
4019 dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
4020 gold_assert(static_cast<off_t>(dyncount * symsize)
4021 == this->dynsym_section_->data_size() - locsize);
4024 off_t global_off = off;
4025 off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
4026 &this->sympool_, &local_symcount);
4028 if (!parameters->options().strip_all())
4030 this->sympool_.set_string_offsets();
4032 const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
4033 Output_section* osymtab = this->make_output_section(symtab_name,
4037 this->symtab_section_ = osymtab;
4039 Output_section_data* pos = new Output_data_fixed_space(off, align,
4041 osymtab->add_output_section_data(pos);
4043 // We generate a .symtab_shndx section if we have more than
4044 // SHN_LORESERVE sections. Technically it is possible that we
4045 // don't need one, because it is possible that there are no
4046 // symbols in any of sections with indexes larger than
4047 // SHN_LORESERVE. That is probably unusual, though, and it is
4048 // easier to always create one than to compute section indexes
4049 // twice (once here, once when writing out the symbols).
4050 if (shnum >= elfcpp::SHN_LORESERVE)
4052 const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
4054 Output_section* osymtab_xindex =
4055 this->make_output_section(symtab_xindex_name,
4056 elfcpp::SHT_SYMTAB_SHNDX, 0,
4057 ORDER_INVALID, false);
4059 size_t symcount = off / symsize;
4060 this->symtab_xindex_ = new Output_symtab_xindex(symcount);
4062 osymtab_xindex->add_output_section_data(this->symtab_xindex_);
4064 osymtab_xindex->set_link_section(osymtab);
4065 osymtab_xindex->set_addralign(4);
4066 osymtab_xindex->set_entsize(4);
4068 osymtab_xindex->set_after_input_sections();
4070 // This tells the driver code to wait until the symbol table
4071 // has written out before writing out the postprocessing
4072 // sections, including the .symtab_shndx section.
4073 this->any_postprocessing_sections_ = true;
4076 const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
4077 Output_section* ostrtab = this->make_output_section(strtab_name,
4082 Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
4083 ostrtab->add_output_section_data(pstr);
4086 if (!parameters->incremental_update())
4087 symtab_off = align_address(*poff, align);
4090 symtab_off = this->allocate(off, align, *poff);
4092 gold_fallback(_("out of patch space for symbol table; "
4093 "relink with --incremental-full"));
4094 gold_debug(DEBUG_INCREMENTAL,
4095 "create_symtab_sections: %08lx %08lx .symtab",
4096 static_cast<long>(symtab_off),
4097 static_cast<long>(off));
4100 symtab->set_file_offset(symtab_off + global_off);
4101 osymtab->set_file_offset(symtab_off);
4102 osymtab->finalize_data_size();
4103 osymtab->set_link_section(ostrtab);
4104 osymtab->set_info(local_symcount);
4105 osymtab->set_entsize(symsize);
4107 if (symtab_off + off > *poff)
4108 *poff = symtab_off + off;
4112 // Create the .shstrtab section, which holds the names of the
4113 // sections. At the time this is called, we have created all the
4114 // output sections except .shstrtab itself.
4117 Layout::create_shstrtab()
4119 // FIXME: We don't need to create a .shstrtab section if we are
4120 // stripping everything.
4122 const char* name = this->namepool_.add(".shstrtab", false, NULL);
4124 Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0,
4125 ORDER_INVALID, false);
4127 if (strcmp(parameters->options().compress_debug_sections(), "none") != 0)
4129 // We can't write out this section until we've set all the
4130 // section names, and we don't set the names of compressed
4131 // output sections until relocations are complete. FIXME: With
4132 // the current names we use, this is unnecessary.
4133 os->set_after_input_sections();
4136 Output_section_data* posd = new Output_data_strtab(&this->namepool_);
4137 os->add_output_section_data(posd);
4142 // Create the section headers. SIZE is 32 or 64. OFF is the file
4146 Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
4148 Output_section_headers* oshdrs;
4149 oshdrs = new Output_section_headers(this,
4150 &this->segment_list_,
4151 &this->section_list_,
4152 &this->unattached_section_list_,
4156 if (!parameters->incremental_update())
4157 off = align_address(*poff, oshdrs->addralign());
4160 oshdrs->pre_finalize_data_size();
4161 off = this->allocate(oshdrs->data_size(), oshdrs->addralign(), *poff);
4163 gold_fallback(_("out of patch space for section header table; "
4164 "relink with --incremental-full"));
4165 gold_debug(DEBUG_INCREMENTAL,
4166 "create_shdrs: %08lx %08lx (section header table)",
4167 static_cast<long>(off),
4168 static_cast<long>(off + oshdrs->data_size()));
4170 oshdrs->set_address_and_file_offset(0, off);
4171 off += oshdrs->data_size();
4174 this->section_headers_ = oshdrs;
4177 // Count the allocated sections.
4180 Layout::allocated_output_section_count() const
4182 size_t section_count = 0;
4183 for (Segment_list::const_iterator p = this->segment_list_.begin();
4184 p != this->segment_list_.end();
4186 section_count += (*p)->output_section_count();
4187 return section_count;
4190 // Create the dynamic symbol table.
4193 Layout::create_dynamic_symtab(const Input_objects* input_objects,
4194 Symbol_table* symtab,
4195 Output_section** pdynstr,
4196 unsigned int* plocal_dynamic_count,
4197 std::vector<Symbol*>* pdynamic_symbols,
4198 Versions* pversions)
4200 // Count all the symbols in the dynamic symbol table, and set the
4201 // dynamic symbol indexes.
4203 // Skip symbol 0, which is always all zeroes.
4204 unsigned int index = 1;
4206 // Add STT_SECTION symbols for each Output section which needs one.
4207 for (Section_list::iterator p = this->section_list_.begin();
4208 p != this->section_list_.end();
4211 if (!(*p)->needs_dynsym_index())
4212 (*p)->set_dynsym_index(-1U);
4215 (*p)->set_dynsym_index(index);
4220 // Count the local symbols that need to go in the dynamic symbol table,
4221 // and set the dynamic symbol indexes.
4222 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4223 p != input_objects->relobj_end();
4226 unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
4230 unsigned int local_symcount = index;
4231 *plocal_dynamic_count = local_symcount;
4233 index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
4234 &this->dynpool_, pversions);
4238 const int size = parameters->target().get_size();
4241 symsize = elfcpp::Elf_sizes<32>::sym_size;
4244 else if (size == 64)
4246 symsize = elfcpp::Elf_sizes<64>::sym_size;
4252 // Create the dynamic symbol table section.
4254 Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
4258 ORDER_DYNAMIC_LINKER,
4261 // Check for NULL as a linker script may discard .dynsym.
4264 Output_section_data* odata = new Output_data_fixed_space(index * symsize,
4267 dynsym->add_output_section_data(odata);
4269 dynsym->set_info(local_symcount);
4270 dynsym->set_entsize(symsize);
4271 dynsym->set_addralign(align);
4273 this->dynsym_section_ = dynsym;
4276 Output_data_dynamic* const odyn = this->dynamic_data_;
4279 odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
4280 odyn->add_constant(elfcpp::DT_SYMENT, symsize);
4283 // If there are more than SHN_LORESERVE allocated sections, we
4284 // create a .dynsym_shndx section. It is possible that we don't
4285 // need one, because it is possible that there are no dynamic
4286 // symbols in any of the sections with indexes larger than
4287 // SHN_LORESERVE. This is probably unusual, though, and at this
4288 // time we don't know the actual section indexes so it is
4289 // inconvenient to check.
4290 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
4292 Output_section* dynsym_xindex =
4293 this->choose_output_section(NULL, ".dynsym_shndx",
4294 elfcpp::SHT_SYMTAB_SHNDX,
4296 false, ORDER_DYNAMIC_LINKER, false);
4298 if (dynsym_xindex != NULL)
4300 this->dynsym_xindex_ = new Output_symtab_xindex(index);
4302 dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
4304 dynsym_xindex->set_link_section(dynsym);
4305 dynsym_xindex->set_addralign(4);
4306 dynsym_xindex->set_entsize(4);
4308 dynsym_xindex->set_after_input_sections();
4310 // This tells the driver code to wait until the symbol table
4311 // has written out before writing out the postprocessing
4312 // sections, including the .dynsym_shndx section.
4313 this->any_postprocessing_sections_ = true;
4317 // Create the dynamic string table section.
4319 Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
4323 ORDER_DYNAMIC_LINKER,
4328 Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
4329 dynstr->add_output_section_data(strdata);
4332 dynsym->set_link_section(dynstr);
4333 if (this->dynamic_section_ != NULL)
4334 this->dynamic_section_->set_link_section(dynstr);
4338 odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
4339 odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
4343 // Create the hash tables. The Gnu-style hash table must be
4344 // built first, because it changes the order of the symbols
4345 // in the dynamic symbol table.
4347 if (strcmp(parameters->options().hash_style(), "gnu") == 0
4348 || strcmp(parameters->options().hash_style(), "both") == 0)
4350 unsigned char* phash;
4351 unsigned int hashlen;
4352 Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
4355 Output_section* hashsec =
4356 this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH,
4357 elfcpp::SHF_ALLOC, false,
4358 ORDER_DYNAMIC_LINKER, false);
4360 Output_section_data* hashdata = new Output_data_const_buffer(phash,
4364 if (hashsec != NULL && hashdata != NULL)
4365 hashsec->add_output_section_data(hashdata);
4367 if (hashsec != NULL)
4370 hashsec->set_link_section(dynsym);
4372 // For a 64-bit target, the entries in .gnu.hash do not have
4373 // a uniform size, so we only set the entry size for a
4375 if (parameters->target().get_size() == 32)
4376 hashsec->set_entsize(4);
4379 odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
4383 if (strcmp(parameters->options().hash_style(), "sysv") == 0
4384 || strcmp(parameters->options().hash_style(), "both") == 0)
4386 unsigned char* phash;
4387 unsigned int hashlen;
4388 Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
4391 Output_section* hashsec =
4392 this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH,
4393 elfcpp::SHF_ALLOC, false,
4394 ORDER_DYNAMIC_LINKER, false);
4396 Output_section_data* hashdata = new Output_data_const_buffer(phash,
4400 if (hashsec != NULL && hashdata != NULL)
4401 hashsec->add_output_section_data(hashdata);
4403 if (hashsec != NULL)
4406 hashsec->set_link_section(dynsym);
4407 hashsec->set_entsize(4);
4411 odyn->add_section_address(elfcpp::DT_HASH, hashsec);
4415 // Assign offsets to each local portion of the dynamic symbol table.
4418 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
4420 Output_section* dynsym = this->dynsym_section_;
4424 off_t off = dynsym->offset();
4426 // Skip the dummy symbol at the start of the section.
4427 off += dynsym->entsize();
4429 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4430 p != input_objects->relobj_end();
4433 unsigned int count = (*p)->set_local_dynsym_offset(off);
4434 off += count * dynsym->entsize();
4438 // Create the version sections.
4441 Layout::create_version_sections(const Versions* versions,
4442 const Symbol_table* symtab,
4443 unsigned int local_symcount,
4444 const std::vector<Symbol*>& dynamic_symbols,
4445 const Output_section* dynstr)
4447 if (!versions->any_defs() && !versions->any_needs())
4450 switch (parameters->size_and_endianness())
4452 #ifdef HAVE_TARGET_32_LITTLE
4453 case Parameters::TARGET_32_LITTLE:
4454 this->sized_create_version_sections<32, false>(versions, symtab,
4456 dynamic_symbols, dynstr);
4459 #ifdef HAVE_TARGET_32_BIG
4460 case Parameters::TARGET_32_BIG:
4461 this->sized_create_version_sections<32, true>(versions, symtab,
4463 dynamic_symbols, dynstr);
4466 #ifdef HAVE_TARGET_64_LITTLE
4467 case Parameters::TARGET_64_LITTLE:
4468 this->sized_create_version_sections<64, false>(versions, symtab,
4470 dynamic_symbols, dynstr);
4473 #ifdef HAVE_TARGET_64_BIG
4474 case Parameters::TARGET_64_BIG:
4475 this->sized_create_version_sections<64, true>(versions, symtab,
4477 dynamic_symbols, dynstr);
4485 // Create the version sections, sized version.
4487 template<int size, bool big_endian>
4489 Layout::sized_create_version_sections(
4490 const Versions* versions,
4491 const Symbol_table* symtab,
4492 unsigned int local_symcount,
4493 const std::vector<Symbol*>& dynamic_symbols,
4494 const Output_section* dynstr)
4496 Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
4497 elfcpp::SHT_GNU_versym,
4500 ORDER_DYNAMIC_LINKER,
4503 // Check for NULL since a linker script may discard this section.
4506 unsigned char* vbuf;
4508 versions->symbol_section_contents<size, big_endian>(symtab,
4514 Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
4517 vsec->add_output_section_data(vdata);
4518 vsec->set_entsize(2);
4519 vsec->set_link_section(this->dynsym_section_);
4522 Output_data_dynamic* const odyn = this->dynamic_data_;
4523 if (odyn != NULL && vsec != NULL)
4524 odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
4526 if (versions->any_defs())
4528 Output_section* vdsec;
4529 vdsec = this->choose_output_section(NULL, ".gnu.version_d",
4530 elfcpp::SHT_GNU_verdef,
4532 false, ORDER_DYNAMIC_LINKER, false);
4536 unsigned char* vdbuf;
4537 unsigned int vdsize;
4538 unsigned int vdentries;
4539 versions->def_section_contents<size, big_endian>(&this->dynpool_,
4543 Output_section_data* vddata =
4544 new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
4546 vdsec->add_output_section_data(vddata);
4547 vdsec->set_link_section(dynstr);
4548 vdsec->set_info(vdentries);
4552 odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
4553 odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
4558 if (versions->any_needs())
4560 Output_section* vnsec;
4561 vnsec = this->choose_output_section(NULL, ".gnu.version_r",
4562 elfcpp::SHT_GNU_verneed,
4564 false, ORDER_DYNAMIC_LINKER, false);
4568 unsigned char* vnbuf;
4569 unsigned int vnsize;
4570 unsigned int vnentries;
4571 versions->need_section_contents<size, big_endian>(&this->dynpool_,
4575 Output_section_data* vndata =
4576 new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
4578 vnsec->add_output_section_data(vndata);
4579 vnsec->set_link_section(dynstr);
4580 vnsec->set_info(vnentries);
4584 odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
4585 odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
4591 // Create the .interp section and PT_INTERP segment.
4594 Layout::create_interp(const Target* target)
4596 gold_assert(this->interp_segment_ == NULL);
4598 const char* interp = parameters->options().dynamic_linker();
4601 interp = target->dynamic_linker();
4602 gold_assert(interp != NULL);
4605 size_t len = strlen(interp) + 1;
4607 Output_section_data* odata = new Output_data_const(interp, len, 1);
4609 Output_section* osec = this->choose_output_section(NULL, ".interp",
4610 elfcpp::SHT_PROGBITS,
4612 false, ORDER_INTERP,
4615 osec->add_output_section_data(odata);
4618 // Add dynamic tags for the PLT and the dynamic relocs. This is
4619 // called by the target-specific code. This does nothing if not doing
4622 // USE_REL is true for REL relocs rather than RELA relocs.
4624 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
4626 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
4627 // and we also set DT_PLTREL. We use PLT_REL's output section, since
4628 // some targets have multiple reloc sections in PLT_REL.
4630 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
4631 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
4634 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
4638 Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
4639 const Output_data* plt_rel,
4640 const Output_data_reloc_generic* dyn_rel,
4641 bool add_debug, bool dynrel_includes_plt)
4643 Output_data_dynamic* odyn = this->dynamic_data_;
4647 if (plt_got != NULL && plt_got->output_section() != NULL)
4648 odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got);
4650 if (plt_rel != NULL && plt_rel->output_section() != NULL)
4652 odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section());
4653 odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section());
4654 odyn->add_constant(elfcpp::DT_PLTREL,
4655 use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA);
4658 if ((dyn_rel != NULL && dyn_rel->output_section() != NULL)
4659 || (dynrel_includes_plt
4661 && plt_rel->output_section() != NULL))
4663 bool have_dyn_rel = dyn_rel != NULL && dyn_rel->output_section() != NULL;
4664 bool have_plt_rel = plt_rel != NULL && plt_rel->output_section() != NULL;
4665 odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
4667 ? dyn_rel->output_section()
4668 : plt_rel->output_section()));
4669 elfcpp::DT size_tag = use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ;
4670 if (have_dyn_rel && have_plt_rel && dynrel_includes_plt)
4671 odyn->add_section_size(size_tag,
4672 dyn_rel->output_section(),
4673 plt_rel->output_section());
4674 else if (have_dyn_rel)
4675 odyn->add_section_size(size_tag, dyn_rel->output_section());
4677 odyn->add_section_size(size_tag, plt_rel->output_section());
4678 const int size = parameters->target().get_size();
4683 rel_tag = elfcpp::DT_RELENT;
4685 rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size;
4686 else if (size == 64)
4687 rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size;
4693 rel_tag = elfcpp::DT_RELAENT;
4695 rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size;
4696 else if (size == 64)
4697 rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size;
4701 odyn->add_constant(rel_tag, rel_size);
4703 if (parameters->options().combreloc() && have_dyn_rel)
4705 size_t c = dyn_rel->relative_reloc_count();
4707 odyn->add_constant((use_rel
4708 ? elfcpp::DT_RELCOUNT
4709 : elfcpp::DT_RELACOUNT),
4714 if (add_debug && !parameters->options().shared())
4716 // The value of the DT_DEBUG tag is filled in by the dynamic
4717 // linker at run time, and used by the debugger.
4718 odyn->add_constant(elfcpp::DT_DEBUG, 0);
4722 // Finish the .dynamic section and PT_DYNAMIC segment.
4725 Layout::finish_dynamic_section(const Input_objects* input_objects,
4726 const Symbol_table* symtab)
4728 if (!this->script_options_->saw_phdrs_clause()
4729 && this->dynamic_section_ != NULL)
4731 Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
4734 oseg->add_output_section_to_nonload(this->dynamic_section_,
4735 elfcpp::PF_R | elfcpp::PF_W);
4738 Output_data_dynamic* const odyn = this->dynamic_data_;
4742 for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
4743 p != input_objects->dynobj_end();
4746 if (!(*p)->is_needed() && (*p)->as_needed())
4748 // This dynamic object was linked with --as-needed, but it
4753 odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
4756 if (parameters->options().shared())
4758 const char* soname = parameters->options().soname();
4760 odyn->add_string(elfcpp::DT_SONAME, soname);
4763 Symbol* sym = symtab->lookup(parameters->options().init());
4764 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4765 odyn->add_symbol(elfcpp::DT_INIT, sym);
4767 sym = symtab->lookup(parameters->options().fini());
4768 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4769 odyn->add_symbol(elfcpp::DT_FINI, sym);
4771 // Look for .init_array, .preinit_array and .fini_array by checking
4773 for(Layout::Section_list::const_iterator p = this->section_list_.begin();
4774 p != this->section_list_.end();
4776 switch((*p)->type())
4778 case elfcpp::SHT_FINI_ARRAY:
4779 odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p);
4780 odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p);
4782 case elfcpp::SHT_INIT_ARRAY:
4783 odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p);
4784 odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p);
4786 case elfcpp::SHT_PREINIT_ARRAY:
4787 odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p);
4788 odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p);
4794 // Add a DT_RPATH entry if needed.
4795 const General_options::Dir_list& rpath(parameters->options().rpath());
4798 std::string rpath_val;
4799 for (General_options::Dir_list::const_iterator p = rpath.begin();
4803 if (rpath_val.empty())
4804 rpath_val = p->name();
4807 // Eliminate duplicates.
4808 General_options::Dir_list::const_iterator q;
4809 for (q = rpath.begin(); q != p; ++q)
4810 if (q->name() == p->name())
4815 rpath_val += p->name();
4820 if (!parameters->options().enable_new_dtags())
4821 odyn->add_string(elfcpp::DT_RPATH, rpath_val);
4823 odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
4826 // Look for text segments that have dynamic relocations.
4827 bool have_textrel = false;
4828 if (!this->script_options_->saw_sections_clause())
4830 for (Segment_list::const_iterator p = this->segment_list_.begin();
4831 p != this->segment_list_.end();
4834 if ((*p)->type() == elfcpp::PT_LOAD
4835 && ((*p)->flags() & elfcpp::PF_W) == 0
4836 && (*p)->has_dynamic_reloc())
4838 have_textrel = true;
4845 // We don't know the section -> segment mapping, so we are
4846 // conservative and just look for readonly sections with
4847 // relocations. If those sections wind up in writable segments,
4848 // then we have created an unnecessary DT_TEXTREL entry.
4849 for (Section_list::const_iterator p = this->section_list_.begin();
4850 p != this->section_list_.end();
4853 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
4854 && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
4855 && (*p)->has_dynamic_reloc())
4857 have_textrel = true;
4863 if (parameters->options().filter() != NULL)
4864 odyn->add_string(elfcpp::DT_FILTER, parameters->options().filter());
4865 if (parameters->options().any_auxiliary())
4867 for (options::String_set::const_iterator p =
4868 parameters->options().auxiliary_begin();
4869 p != parameters->options().auxiliary_end();
4871 odyn->add_string(elfcpp::DT_AUXILIARY, *p);
4874 // Add a DT_FLAGS entry if necessary.
4875 unsigned int flags = 0;
4878 // Add a DT_TEXTREL for compatibility with older loaders.
4879 odyn->add_constant(elfcpp::DT_TEXTREL, 0);
4880 flags |= elfcpp::DF_TEXTREL;
4882 if (parameters->options().text())
4883 gold_error(_("read-only segment has dynamic relocations"));
4884 else if (parameters->options().warn_shared_textrel()
4885 && parameters->options().shared())
4886 gold_warning(_("shared library text segment is not shareable"));
4888 if (parameters->options().shared() && this->has_static_tls())
4889 flags |= elfcpp::DF_STATIC_TLS;
4890 if (parameters->options().origin())
4891 flags |= elfcpp::DF_ORIGIN;
4892 if (parameters->options().Bsymbolic()
4893 && !parameters->options().have_dynamic_list())
4895 flags |= elfcpp::DF_SYMBOLIC;
4896 // Add DT_SYMBOLIC for compatibility with older loaders.
4897 odyn->add_constant(elfcpp::DT_SYMBOLIC, 0);
4899 if (parameters->options().now())
4900 flags |= elfcpp::DF_BIND_NOW;
4902 odyn->add_constant(elfcpp::DT_FLAGS, flags);
4905 if (parameters->options().global())
4906 flags |= elfcpp::DF_1_GLOBAL;
4907 if (parameters->options().initfirst())
4908 flags |= elfcpp::DF_1_INITFIRST;
4909 if (parameters->options().interpose())
4910 flags |= elfcpp::DF_1_INTERPOSE;
4911 if (parameters->options().loadfltr())
4912 flags |= elfcpp::DF_1_LOADFLTR;
4913 if (parameters->options().nodefaultlib())
4914 flags |= elfcpp::DF_1_NODEFLIB;
4915 if (parameters->options().nodelete())
4916 flags |= elfcpp::DF_1_NODELETE;
4917 if (parameters->options().nodlopen())
4918 flags |= elfcpp::DF_1_NOOPEN;
4919 if (parameters->options().nodump())
4920 flags |= elfcpp::DF_1_NODUMP;
4921 if (!parameters->options().shared())
4922 flags &= ~(elfcpp::DF_1_INITFIRST
4923 | elfcpp::DF_1_NODELETE
4924 | elfcpp::DF_1_NOOPEN);
4925 if (parameters->options().origin())
4926 flags |= elfcpp::DF_1_ORIGIN;
4927 if (parameters->options().now())
4928 flags |= elfcpp::DF_1_NOW;
4929 if (parameters->options().Bgroup())
4930 flags |= elfcpp::DF_1_GROUP;
4932 odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
4935 // Set the size of the _DYNAMIC symbol table to be the size of the
4939 Layout::set_dynamic_symbol_size(const Symbol_table* symtab)
4941 Output_data_dynamic* const odyn = this->dynamic_data_;
4944 odyn->finalize_data_size();
4945 if (this->dynamic_symbol_ == NULL)
4947 off_t data_size = odyn->data_size();
4948 const int size = parameters->target().get_size();
4950 symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size);
4951 else if (size == 64)
4952 symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size);
4957 // The mapping of input section name prefixes to output section names.
4958 // In some cases one prefix is itself a prefix of another prefix; in
4959 // such a case the longer prefix must come first. These prefixes are
4960 // based on the GNU linker default ELF linker script.
4962 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4963 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
4964 const Layout::Section_name_mapping Layout::section_name_mapping[] =
4966 MAPPING_INIT(".text.", ".text"),
4967 MAPPING_INIT(".rodata.", ".rodata"),
4968 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
4969 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
4970 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
4971 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
4972 MAPPING_INIT(".data.", ".data"),
4973 MAPPING_INIT(".bss.", ".bss"),
4974 MAPPING_INIT(".tdata.", ".tdata"),
4975 MAPPING_INIT(".tbss.", ".tbss"),
4976 MAPPING_INIT(".init_array.", ".init_array"),
4977 MAPPING_INIT(".fini_array.", ".fini_array"),
4978 MAPPING_INIT(".sdata.", ".sdata"),
4979 MAPPING_INIT(".sbss.", ".sbss"),
4980 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4981 // differently depending on whether it is creating a shared library.
4982 MAPPING_INIT(".sdata2.", ".sdata"),
4983 MAPPING_INIT(".sbss2.", ".sbss"),
4984 MAPPING_INIT(".lrodata.", ".lrodata"),
4985 MAPPING_INIT(".ldata.", ".ldata"),
4986 MAPPING_INIT(".lbss.", ".lbss"),
4987 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4988 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4989 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4990 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4991 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4992 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4993 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4994 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4995 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4996 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4997 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4998 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4999 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
5000 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
5001 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
5002 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
5003 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
5004 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
5005 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
5006 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
5007 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
5010 #undef MAPPING_INIT_EXACT
5012 const int Layout::section_name_mapping_count =
5013 (sizeof(Layout::section_name_mapping)
5014 / sizeof(Layout::section_name_mapping[0]));
5016 // Choose the output section name to use given an input section name.
5017 // Set *PLEN to the length of the name. *PLEN is initialized to the
5021 Layout::output_section_name(const Relobj* relobj, const char* name,
5024 // gcc 4.3 generates the following sorts of section names when it
5025 // needs a section name specific to a function:
5031 // .data.rel.local.FN
5033 // .data.rel.ro.local.FN
5040 // The GNU linker maps all of those to the part before the .FN,
5041 // except that .data.rel.local.FN is mapped to .data, and
5042 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
5043 // beginning with .data.rel.ro.local are grouped together.
5045 // For an anonymous namespace, the string FN can contain a '.'.
5047 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
5048 // GNU linker maps to .rodata.
5050 // The .data.rel.ro sections are used with -z relro. The sections
5051 // are recognized by name. We use the same names that the GNU
5052 // linker does for these sections.
5054 // It is hard to handle this in a principled way, so we don't even
5055 // try. We use a table of mappings. If the input section name is
5056 // not found in the table, we simply use it as the output section
5059 const Section_name_mapping* psnm = section_name_mapping;
5060 for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
5062 if (psnm->fromlen > 0)
5064 if (strncmp(name, psnm->from, psnm->fromlen) == 0)
5066 *plen = psnm->tolen;
5072 if (strcmp(name, psnm->from) == 0)
5074 *plen = psnm->tolen;
5080 // As an additional complication, .ctors sections are output in
5081 // either .ctors or .init_array sections, and .dtors sections are
5082 // output in either .dtors or .fini_array sections.
5083 if (is_prefix_of(".ctors.", name) || is_prefix_of(".dtors.", name))
5085 if (parameters->options().ctors_in_init_array())
5088 return name[1] == 'c' ? ".init_array" : ".fini_array";
5093 return name[1] == 'c' ? ".ctors" : ".dtors";
5096 if (parameters->options().ctors_in_init_array()
5097 && (strcmp(name, ".ctors") == 0 || strcmp(name, ".dtors") == 0))
5099 // To make .init_array/.fini_array work with gcc we must exclude
5100 // .ctors and .dtors sections from the crtbegin and crtend
5103 || (!Layout::match_file_name(relobj, "crtbegin")
5104 && !Layout::match_file_name(relobj, "crtend")))
5107 return name[1] == 'c' ? ".init_array" : ".fini_array";
5114 // Return true if RELOBJ is an input file whose base name matches
5115 // FILE_NAME. The base name must have an extension of ".o", and must
5116 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
5117 // to match crtbegin.o as well as crtbeginS.o without getting confused
5118 // by other possibilities. Overall matching the file name this way is
5119 // a dreadful hack, but the GNU linker does it in order to better
5120 // support gcc, and we need to be compatible.
5123 Layout::match_file_name(const Relobj* relobj, const char* match)
5125 const std::string& file_name(relobj->name());
5126 const char* base_name = lbasename(file_name.c_str());
5127 size_t match_len = strlen(match);
5128 if (strncmp(base_name, match, match_len) != 0)
5130 size_t base_len = strlen(base_name);
5131 if (base_len != match_len + 2 && base_len != match_len + 3)
5133 return memcmp(base_name + base_len - 2, ".o", 2) == 0;
5136 // Check if a comdat group or .gnu.linkonce section with the given
5137 // NAME is selected for the link. If there is already a section,
5138 // *KEPT_SECTION is set to point to the existing section and the
5139 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
5140 // IS_GROUP_NAME are recorded for this NAME in the layout object,
5141 // *KEPT_SECTION is set to the internal copy and the function returns
5145 Layout::find_or_add_kept_section(const std::string& name,
5150 Kept_section** kept_section)
5152 // It's normal to see a couple of entries here, for the x86 thunk
5153 // sections. If we see more than a few, we're linking a C++
5154 // program, and we resize to get more space to minimize rehashing.
5155 if (this->signatures_.size() > 4
5156 && !this->resized_signatures_)
5158 reserve_unordered_map(&this->signatures_,
5159 this->number_of_input_files_ * 64);
5160 this->resized_signatures_ = true;
5163 Kept_section candidate;
5164 std::pair<Signatures::iterator, bool> ins =
5165 this->signatures_.insert(std::make_pair(name, candidate));
5167 if (kept_section != NULL)
5168 *kept_section = &ins.first->second;
5171 // This is the first time we've seen this signature.
5172 ins.first->second.set_object(object);
5173 ins.first->second.set_shndx(shndx);
5175 ins.first->second.set_is_comdat();
5177 ins.first->second.set_is_group_name();
5181 // We have already seen this signature.
5183 if (ins.first->second.is_group_name())
5185 // We've already seen a real section group with this signature.
5186 // If the kept group is from a plugin object, and we're in the
5187 // replacement phase, accept the new one as a replacement.
5188 if (ins.first->second.object() == NULL
5189 && parameters->options().plugins()->in_replacement_phase())
5191 ins.first->second.set_object(object);
5192 ins.first->second.set_shndx(shndx);
5197 else if (is_group_name)
5199 // This is a real section group, and we've already seen a
5200 // linkonce section with this signature. Record that we've seen
5201 // a section group, and don't include this section group.
5202 ins.first->second.set_is_group_name();
5207 // We've already seen a linkonce section and this is a linkonce
5208 // section. These don't block each other--this may be the same
5209 // symbol name with different section types.
5214 // Store the allocated sections into the section list.
5217 Layout::get_allocated_sections(Section_list* section_list) const
5219 for (Section_list::const_iterator p = this->section_list_.begin();
5220 p != this->section_list_.end();
5222 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
5223 section_list->push_back(*p);
5226 // Store the executable sections into the section list.
5229 Layout::get_executable_sections(Section_list* section_list) const
5231 for (Section_list::const_iterator p = this->section_list_.begin();
5232 p != this->section_list_.end();
5234 if (((*p)->flags() & (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR))
5235 == (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR))
5236 section_list->push_back(*p);
5239 // Create an output segment.
5242 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
5244 gold_assert(!parameters->options().relocatable());
5245 Output_segment* oseg = new Output_segment(type, flags);
5246 this->segment_list_.push_back(oseg);
5248 if (type == elfcpp::PT_TLS)
5249 this->tls_segment_ = oseg;
5250 else if (type == elfcpp::PT_GNU_RELRO)
5251 this->relro_segment_ = oseg;
5252 else if (type == elfcpp::PT_INTERP)
5253 this->interp_segment_ = oseg;
5258 // Return the file offset of the normal symbol table.
5261 Layout::symtab_section_offset() const
5263 if (this->symtab_section_ != NULL)
5264 return this->symtab_section_->offset();
5268 // Return the section index of the normal symbol table. It may have
5269 // been stripped by the -s/--strip-all option.
5272 Layout::symtab_section_shndx() const
5274 if (this->symtab_section_ != NULL)
5275 return this->symtab_section_->out_shndx();
5279 // Write out the Output_sections. Most won't have anything to write,
5280 // since most of the data will come from input sections which are
5281 // handled elsewhere. But some Output_sections do have Output_data.
5284 Layout::write_output_sections(Output_file* of) const
5286 for (Section_list::const_iterator p = this->section_list_.begin();
5287 p != this->section_list_.end();
5290 if (!(*p)->after_input_sections())
5295 // Write out data not associated with a section or the symbol table.
5298 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
5300 if (!parameters->options().strip_all())
5302 const Output_section* symtab_section = this->symtab_section_;
5303 for (Section_list::const_iterator p = this->section_list_.begin();
5304 p != this->section_list_.end();
5307 if ((*p)->needs_symtab_index())
5309 gold_assert(symtab_section != NULL);
5310 unsigned int index = (*p)->symtab_index();
5311 gold_assert(index > 0 && index != -1U);
5312 off_t off = (symtab_section->offset()
5313 + index * symtab_section->entsize());
5314 symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
5319 const Output_section* dynsym_section = this->dynsym_section_;
5320 for (Section_list::const_iterator p = this->section_list_.begin();
5321 p != this->section_list_.end();
5324 if ((*p)->needs_dynsym_index())
5326 gold_assert(dynsym_section != NULL);
5327 unsigned int index = (*p)->dynsym_index();
5328 gold_assert(index > 0 && index != -1U);
5329 off_t off = (dynsym_section->offset()
5330 + index * dynsym_section->entsize());
5331 symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
5335 // Write out the Output_data which are not in an Output_section.
5336 for (Data_list::const_iterator p = this->special_output_list_.begin();
5337 p != this->special_output_list_.end();
5341 // Write out the Output_data which are not in an Output_section
5342 // and are regenerated in each iteration of relaxation.
5343 for (Data_list::const_iterator p = this->relax_output_list_.begin();
5344 p != this->relax_output_list_.end();
5349 // Write out the Output_sections which can only be written after the
5350 // input sections are complete.
5353 Layout::write_sections_after_input_sections(Output_file* of)
5355 // Determine the final section offsets, and thus the final output
5356 // file size. Note we finalize the .shstrab last, to allow the
5357 // after_input_section sections to modify their section-names before
5359 if (this->any_postprocessing_sections_)
5361 off_t off = this->output_file_size_;
5362 off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
5364 // Now that we've finalized the names, we can finalize the shstrab.
5366 this->set_section_offsets(off,
5367 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
5369 if (off > this->output_file_size_)
5372 this->output_file_size_ = off;
5376 for (Section_list::const_iterator p = this->section_list_.begin();
5377 p != this->section_list_.end();
5380 if ((*p)->after_input_sections())
5384 this->section_headers_->write(of);
5387 // If a tree-style build ID was requested, the parallel part of that computation
5388 // is already done, and the final hash-of-hashes is computed here. For other
5389 // types of build IDs, all the work is done here.
5392 Layout::write_build_id(Output_file* of, unsigned char* array_of_hashes,
5393 size_t size_of_hashes) const
5395 if (this->build_id_note_ == NULL)
5398 unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
5399 this->build_id_note_->data_size());
5401 if (array_of_hashes == NULL)
5403 const size_t output_file_size = this->output_file_size();
5404 const unsigned char* iv = of->get_input_view(0, output_file_size);
5405 const char* style = parameters->options().build_id();
5407 // If we get here with style == "tree" then the output must be
5408 // too small for chunking, and we use SHA-1 in that case.
5409 if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0))
5410 sha1_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov);
5411 else if (strcmp(style, "md5") == 0)
5412 md5_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov);
5416 of->free_input_view(0, output_file_size, iv);
5420 // Non-overlapping substrings of the output file have been hashed.
5421 // Compute SHA-1 hash of the hashes.
5422 sha1_buffer(reinterpret_cast<const char*>(array_of_hashes),
5423 size_of_hashes, ov);
5424 delete[] array_of_hashes;
5427 of->write_output_view(this->build_id_note_->offset(),
5428 this->build_id_note_->data_size(),
5432 // Write out a binary file. This is called after the link is
5433 // complete. IN is the temporary output file we used to generate the
5434 // ELF code. We simply walk through the segments, read them from
5435 // their file offset in IN, and write them to their load address in
5436 // the output file. FIXME: with a bit more work, we could support
5437 // S-records and/or Intel hex format here.
5440 Layout::write_binary(Output_file* in) const
5442 gold_assert(parameters->options().oformat_enum()
5443 == General_options::OBJECT_FORMAT_BINARY);
5445 // Get the size of the binary file.
5446 uint64_t max_load_address = 0;
5447 for (Segment_list::const_iterator p = this->segment_list_.begin();
5448 p != this->segment_list_.end();
5451 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
5453 uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
5454 if (max_paddr > max_load_address)
5455 max_load_address = max_paddr;
5459 Output_file out(parameters->options().output_file_name());
5460 out.open(max_load_address);
5462 for (Segment_list::const_iterator p = this->segment_list_.begin();
5463 p != this->segment_list_.end();
5466 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
5468 const unsigned char* vin = in->get_input_view((*p)->offset(),
5470 unsigned char* vout = out.get_output_view((*p)->paddr(),
5472 memcpy(vout, vin, (*p)->filesz());
5473 out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
5474 in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
5481 // Print the output sections to the map file.
5484 Layout::print_to_mapfile(Mapfile* mapfile) const
5486 for (Segment_list::const_iterator p = this->segment_list_.begin();
5487 p != this->segment_list_.end();
5489 (*p)->print_sections_to_mapfile(mapfile);
5490 for (Section_list::const_iterator p = this->unattached_section_list_.begin();
5491 p != this->unattached_section_list_.end();
5493 (*p)->print_to_mapfile(mapfile);
5496 // Print statistical information to stderr. This is used for --stats.
5499 Layout::print_stats() const
5501 this->namepool_.print_stats("section name pool");
5502 this->sympool_.print_stats("output symbol name pool");
5503 this->dynpool_.print_stats("dynamic name pool");
5505 for (Section_list::const_iterator p = this->section_list_.begin();
5506 p != this->section_list_.end();
5508 (*p)->print_merge_stats();
5511 // Write_sections_task methods.
5513 // We can always run this task.
5516 Write_sections_task::is_runnable()
5521 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5525 Write_sections_task::locks(Task_locker* tl)
5527 tl->add(this, this->output_sections_blocker_);
5528 if (this->input_sections_blocker_ != NULL)
5529 tl->add(this, this->input_sections_blocker_);
5530 tl->add(this, this->final_blocker_);
5533 // Run the task--write out the data.
5536 Write_sections_task::run(Workqueue*)
5538 this->layout_->write_output_sections(this->of_);
5541 // Write_data_task methods.
5543 // We can always run this task.
5546 Write_data_task::is_runnable()
5551 // We need to unlock FINAL_BLOCKER when finished.
5554 Write_data_task::locks(Task_locker* tl)
5556 tl->add(this, this->final_blocker_);
5559 // Run the task--write out the data.
5562 Write_data_task::run(Workqueue*)
5564 this->layout_->write_data(this->symtab_, this->of_);
5567 // Write_symbols_task methods.
5569 // We can always run this task.
5572 Write_symbols_task::is_runnable()
5577 // We need to unlock FINAL_BLOCKER when finished.
5580 Write_symbols_task::locks(Task_locker* tl)
5582 tl->add(this, this->final_blocker_);
5585 // Run the task--write out the symbols.
5588 Write_symbols_task::run(Workqueue*)
5590 this->symtab_->write_globals(this->sympool_, this->dynpool_,
5591 this->layout_->symtab_xindex(),
5592 this->layout_->dynsym_xindex(), this->of_);
5595 // Write_after_input_sections_task methods.
5597 // We can only run this task after the input sections have completed.
5600 Write_after_input_sections_task::is_runnable()
5602 if (this->input_sections_blocker_->is_blocked())
5603 return this->input_sections_blocker_;
5607 // We need to unlock FINAL_BLOCKER when finished.
5610 Write_after_input_sections_task::locks(Task_locker* tl)
5612 tl->add(this, this->final_blocker_);
5618 Write_after_input_sections_task::run(Workqueue*)
5620 this->layout_->write_sections_after_input_sections(this->of_);
5623 // Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes,
5624 // or as a "tree" where each chunk of the string is hashed and then those
5625 // hashes are put into a (much smaller) string which is hashed with sha1.
5626 // We compute a checksum over the entire file because that is simplest.
5629 Build_id_task_runner::run(Workqueue* workqueue, const Task*)
5631 Task_token* post_hash_tasks_blocker = new Task_token(true);
5632 const Layout* layout = this->layout_;
5633 Output_file* of = this->of_;
5634 const size_t filesize = (layout->output_file_size() <= 0 ? 0
5635 : static_cast<size_t>(layout->output_file_size()));
5636 unsigned char* array_of_hashes = NULL;
5637 size_t size_of_hashes = 0;
5639 if (strcmp(this->options_->build_id(), "tree") == 0
5640 && this->options_->build_id_chunk_size_for_treehash() > 0
5642 && (filesize >= this->options_->build_id_min_file_size_for_treehash()))
5644 static const size_t MD5_OUTPUT_SIZE_IN_BYTES = 16;
5645 const size_t chunk_size =
5646 this->options_->build_id_chunk_size_for_treehash();
5647 const size_t num_hashes = ((filesize - 1) / chunk_size) + 1;
5648 post_hash_tasks_blocker->add_blockers(num_hashes);
5649 size_of_hashes = num_hashes * MD5_OUTPUT_SIZE_IN_BYTES;
5650 array_of_hashes = new unsigned char[size_of_hashes];
5651 unsigned char *dst = array_of_hashes;
5652 for (size_t i = 0, src_offset = 0; i < num_hashes;
5653 i++, dst += MD5_OUTPUT_SIZE_IN_BYTES, src_offset += chunk_size)
5655 size_t size = std::min(chunk_size, filesize - src_offset);
5656 workqueue->queue(new Hash_task(of,
5660 post_hash_tasks_blocker));
5664 // Queue the final task to write the build id and close the output file.
5665 workqueue->queue(new Task_function(new Close_task_runner(this->options_,
5670 post_hash_tasks_blocker,
5671 "Task_function Close_task_runner"));
5674 // Close_task_runner methods.
5676 // Finish up the build ID computation, if necessary, and write a binary file,
5677 // if necessary. Then close the output file.
5680 Close_task_runner::run(Workqueue*, const Task*)
5682 // At this point the multi-threaded part of the build ID computation,
5683 // if any, is done. See Build_id_task_runner.
5684 this->layout_->write_build_id(this->of_, this->array_of_hashes_,
5685 this->size_of_hashes_);
5687 // If we've been asked to create a binary file, we do so here.
5688 if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
5689 this->layout_->write_binary(this->of_);
5694 // Instantiate the templates we need. We could use the configure
5695 // script to restrict this to only the ones for implemented targets.
5697 #ifdef HAVE_TARGET_32_LITTLE
5700 Layout::init_fixed_output_section<32, false>(
5702 elfcpp::Shdr<32, false>& shdr);
5705 #ifdef HAVE_TARGET_32_BIG
5708 Layout::init_fixed_output_section<32, true>(
5710 elfcpp::Shdr<32, true>& shdr);
5713 #ifdef HAVE_TARGET_64_LITTLE
5716 Layout::init_fixed_output_section<64, false>(
5718 elfcpp::Shdr<64, false>& shdr);
5721 #ifdef HAVE_TARGET_64_BIG
5724 Layout::init_fixed_output_section<64, true>(
5726 elfcpp::Shdr<64, true>& shdr);
5729 #ifdef HAVE_TARGET_32_LITTLE
5732 Layout::layout<32, false>(Sized_relobj_file<32, false>* object,
5735 const elfcpp::Shdr<32, false>& shdr,
5736 unsigned int, unsigned int, off_t*);
5739 #ifdef HAVE_TARGET_32_BIG
5742 Layout::layout<32, true>(Sized_relobj_file<32, true>* object,
5745 const elfcpp::Shdr<32, true>& shdr,
5746 unsigned int, unsigned int, off_t*);
5749 #ifdef HAVE_TARGET_64_LITTLE
5752 Layout::layout<64, false>(Sized_relobj_file<64, false>* object,
5755 const elfcpp::Shdr<64, false>& shdr,
5756 unsigned int, unsigned int, off_t*);
5759 #ifdef HAVE_TARGET_64_BIG
5762 Layout::layout<64, true>(Sized_relobj_file<64, true>* object,
5765 const elfcpp::Shdr<64, true>& shdr,
5766 unsigned int, unsigned int, off_t*);
5769 #ifdef HAVE_TARGET_32_LITTLE
5772 Layout::layout_reloc<32, false>(Sized_relobj_file<32, false>* object,
5773 unsigned int reloc_shndx,
5774 const elfcpp::Shdr<32, false>& shdr,
5775 Output_section* data_section,
5776 Relocatable_relocs* rr);
5779 #ifdef HAVE_TARGET_32_BIG
5782 Layout::layout_reloc<32, true>(Sized_relobj_file<32, true>* object,
5783 unsigned int reloc_shndx,
5784 const elfcpp::Shdr<32, true>& shdr,
5785 Output_section* data_section,
5786 Relocatable_relocs* rr);
5789 #ifdef HAVE_TARGET_64_LITTLE
5792 Layout::layout_reloc<64, false>(Sized_relobj_file<64, false>* object,
5793 unsigned int reloc_shndx,
5794 const elfcpp::Shdr<64, false>& shdr,
5795 Output_section* data_section,
5796 Relocatable_relocs* rr);
5799 #ifdef HAVE_TARGET_64_BIG
5802 Layout::layout_reloc<64, true>(Sized_relobj_file<64, true>* object,
5803 unsigned int reloc_shndx,
5804 const elfcpp::Shdr<64, true>& shdr,
5805 Output_section* data_section,
5806 Relocatable_relocs* rr);
5809 #ifdef HAVE_TARGET_32_LITTLE
5812 Layout::layout_group<32, false>(Symbol_table* symtab,
5813 Sized_relobj_file<32, false>* object,
5815 const char* group_section_name,
5816 const char* signature,
5817 const elfcpp::Shdr<32, false>& shdr,
5818 elfcpp::Elf_Word flags,
5819 std::vector<unsigned int>* shndxes);
5822 #ifdef HAVE_TARGET_32_BIG
5825 Layout::layout_group<32, true>(Symbol_table* symtab,
5826 Sized_relobj_file<32, true>* object,
5828 const char* group_section_name,
5829 const char* signature,
5830 const elfcpp::Shdr<32, true>& shdr,
5831 elfcpp::Elf_Word flags,
5832 std::vector<unsigned int>* shndxes);
5835 #ifdef HAVE_TARGET_64_LITTLE
5838 Layout::layout_group<64, false>(Symbol_table* symtab,
5839 Sized_relobj_file<64, false>* object,
5841 const char* group_section_name,
5842 const char* signature,
5843 const elfcpp::Shdr<64, false>& shdr,
5844 elfcpp::Elf_Word flags,
5845 std::vector<unsigned int>* shndxes);
5848 #ifdef HAVE_TARGET_64_BIG
5851 Layout::layout_group<64, true>(Symbol_table* symtab,
5852 Sized_relobj_file<64, true>* object,
5854 const char* group_section_name,
5855 const char* signature,
5856 const elfcpp::Shdr<64, true>& shdr,
5857 elfcpp::Elf_Word flags,
5858 std::vector<unsigned int>* shndxes);
5861 #ifdef HAVE_TARGET_32_LITTLE
5864 Layout::layout_eh_frame<32, false>(Sized_relobj_file<32, false>* object,
5865 const unsigned char* symbols,
5867 const unsigned char* symbol_names,
5868 off_t symbol_names_size,
5870 const elfcpp::Shdr<32, false>& shdr,
5871 unsigned int reloc_shndx,
5872 unsigned int reloc_type,
5876 #ifdef HAVE_TARGET_32_BIG
5879 Layout::layout_eh_frame<32, true>(Sized_relobj_file<32, true>* object,
5880 const unsigned char* symbols,
5882 const unsigned char* symbol_names,
5883 off_t symbol_names_size,
5885 const elfcpp::Shdr<32, true>& shdr,
5886 unsigned int reloc_shndx,
5887 unsigned int reloc_type,
5891 #ifdef HAVE_TARGET_64_LITTLE
5894 Layout::layout_eh_frame<64, false>(Sized_relobj_file<64, false>* object,
5895 const unsigned char* symbols,
5897 const unsigned char* symbol_names,
5898 off_t symbol_names_size,
5900 const elfcpp::Shdr<64, false>& shdr,
5901 unsigned int reloc_shndx,
5902 unsigned int reloc_type,
5906 #ifdef HAVE_TARGET_64_BIG
5909 Layout::layout_eh_frame<64, true>(Sized_relobj_file<64, true>* object,
5910 const unsigned char* symbols,
5912 const unsigned char* symbol_names,
5913 off_t symbol_names_size,
5915 const elfcpp::Shdr<64, true>& shdr,
5916 unsigned int reloc_shndx,
5917 unsigned int reloc_type,
5921 #ifdef HAVE_TARGET_32_LITTLE
5924 Layout::add_to_gdb_index(bool is_type_unit,
5925 Sized_relobj<32, false>* object,
5926 const unsigned char* symbols,
5929 unsigned int reloc_shndx,
5930 unsigned int reloc_type);
5933 #ifdef HAVE_TARGET_32_BIG
5936 Layout::add_to_gdb_index(bool is_type_unit,
5937 Sized_relobj<32, true>* object,
5938 const unsigned char* symbols,
5941 unsigned int reloc_shndx,
5942 unsigned int reloc_type);
5945 #ifdef HAVE_TARGET_64_LITTLE
5948 Layout::add_to_gdb_index(bool is_type_unit,
5949 Sized_relobj<64, false>* object,
5950 const unsigned char* symbols,
5953 unsigned int reloc_shndx,
5954 unsigned int reloc_type);
5957 #ifdef HAVE_TARGET_64_BIG
5960 Layout::add_to_gdb_index(bool is_type_unit,
5961 Sized_relobj<64, true>* object,
5962 const unsigned char* symbols,
5965 unsigned int reloc_shndx,
5966 unsigned int reloc_type);
5969 } // End namespace gold.