1 // layout.cc -- lay out output file sections for gold
3 // Copyright (C) 2006-2016 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"
42 #include "parameters.h"
46 #include "script-sections.h"
51 #include "gdb-index.h"
52 #include "compressed_output.h"
53 #include "reduced_debug_output.h"
56 #include "descriptors.h"
58 #include "incremental.h"
66 // The total number of free lists used.
67 unsigned int Free_list::num_lists = 0;
68 // The total number of free list nodes used.
69 unsigned int Free_list::num_nodes = 0;
70 // The total number of calls to Free_list::remove.
71 unsigned int Free_list::num_removes = 0;
72 // The total number of nodes visited during calls to Free_list::remove.
73 unsigned int Free_list::num_remove_visits = 0;
74 // The total number of calls to Free_list::allocate.
75 unsigned int Free_list::num_allocates = 0;
76 // The total number of nodes visited during calls to Free_list::allocate.
77 unsigned int Free_list::num_allocate_visits = 0;
79 // Initialize the free list. Creates a single free list node that
80 // describes the entire region of length LEN. If EXTEND is true,
81 // allocate() is allowed to extend the region beyond its initial
85 Free_list::init(off_t len, bool extend)
87 this->list_.push_front(Free_list_node(0, len));
88 this->last_remove_ = this->list_.begin();
89 this->extend_ = extend;
91 ++Free_list::num_lists;
92 ++Free_list::num_nodes;
95 // Remove a chunk from the free list. Because we start with a single
96 // node that covers the entire section, and remove chunks from it one
97 // at a time, we do not need to coalesce chunks or handle cases that
98 // span more than one free node. We expect to remove chunks from the
99 // free list in order, and we expect to have only a few chunks of free
100 // space left (corresponding to files that have changed since the last
101 // incremental link), so a simple linear list should provide sufficient
105 Free_list::remove(off_t start, off_t end)
109 gold_assert(start < end);
111 ++Free_list::num_removes;
113 Iterator p = this->last_remove_;
114 if (p->start_ > start)
115 p = this->list_.begin();
117 for (; p != this->list_.end(); ++p)
119 ++Free_list::num_remove_visits;
120 // Find a node that wholly contains the indicated region.
121 if (p->start_ <= start && p->end_ >= end)
123 // Case 1: the indicated region spans the whole node.
124 // Add some fuzz to avoid creating tiny free chunks.
125 if (p->start_ + 3 >= start && p->end_ <= end + 3)
126 p = this->list_.erase(p);
127 // Case 2: remove a chunk from the start of the node.
128 else if (p->start_ + 3 >= start)
130 // Case 3: remove a chunk from the end of the node.
131 else if (p->end_ <= end + 3)
133 // Case 4: remove a chunk from the middle, and split
134 // the node into two.
137 Free_list_node newnode(p->start_, start);
139 this->list_.insert(p, newnode);
140 ++Free_list::num_nodes;
142 this->last_remove_ = p;
147 // Did not find a node containing the given chunk. This could happen
148 // because a small chunk was already removed due to the fuzz.
149 gold_debug(DEBUG_INCREMENTAL,
150 "Free_list::remove(%d,%d) not found",
151 static_cast<int>(start), static_cast<int>(end));
154 // Allocate a chunk of size LEN from the free list. Returns -1ULL
155 // if a sufficiently large chunk of free space is not found.
156 // We use a simple first-fit algorithm.
159 Free_list::allocate(off_t len, uint64_t align, off_t minoff)
161 gold_debug(DEBUG_INCREMENTAL,
162 "Free_list::allocate(%08lx, %d, %08lx)",
163 static_cast<long>(len), static_cast<int>(align),
164 static_cast<long>(minoff));
166 return align_address(minoff, align);
168 ++Free_list::num_allocates;
170 // We usually want to drop free chunks smaller than 4 bytes.
171 // If we need to guarantee a minimum hole size, though, we need
172 // to keep track of all free chunks.
173 const int fuzz = this->min_hole_ > 0 ? 0 : 3;
175 for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
177 ++Free_list::num_allocate_visits;
178 off_t start = p->start_ > minoff ? p->start_ : minoff;
179 start = align_address(start, align);
180 off_t end = start + len;
181 if (end > p->end_ && p->end_ == this->length_ && this->extend_)
186 if (end == p->end_ || (end <= p->end_ - this->min_hole_))
188 if (p->start_ + fuzz >= start && p->end_ <= end + fuzz)
189 this->list_.erase(p);
190 else if (p->start_ + fuzz >= start)
192 else if (p->end_ <= end + fuzz)
196 Free_list_node newnode(p->start_, start);
198 this->list_.insert(p, newnode);
199 ++Free_list::num_nodes;
206 off_t start = align_address(this->length_, align);
207 this->length_ = start + len;
213 // Dump the free list (for debugging).
217 gold_info("Free list:\n start end length\n");
218 for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
219 gold_info(" %08lx %08lx %08lx", static_cast<long>(p->start_),
220 static_cast<long>(p->end_),
221 static_cast<long>(p->end_ - p->start_));
224 // Print the statistics for the free lists.
226 Free_list::print_stats()
228 fprintf(stderr, _("%s: total free lists: %u\n"),
229 program_name, Free_list::num_lists);
230 fprintf(stderr, _("%s: total free list nodes: %u\n"),
231 program_name, Free_list::num_nodes);
232 fprintf(stderr, _("%s: calls to Free_list::remove: %u\n"),
233 program_name, Free_list::num_removes);
234 fprintf(stderr, _("%s: nodes visited: %u\n"),
235 program_name, Free_list::num_remove_visits);
236 fprintf(stderr, _("%s: calls to Free_list::allocate: %u\n"),
237 program_name, Free_list::num_allocates);
238 fprintf(stderr, _("%s: nodes visited: %u\n"),
239 program_name, Free_list::num_allocate_visits);
242 // A Hash_task computes the MD5 checksum of an array of char.
244 class Hash_task : public Task
247 Hash_task(Output_file* of,
251 Task_token* final_blocker)
252 : of_(of), offset_(offset), size_(size), dst_(dst),
253 final_blocker_(final_blocker)
259 const unsigned char* iv =
260 this->of_->get_input_view(this->offset_, this->size_);
261 md5_buffer(reinterpret_cast<const char*>(iv), this->size_, this->dst_);
262 this->of_->free_input_view(this->offset_, this->size_, iv);
269 // Unblock FINAL_BLOCKER_ when done.
271 locks(Task_locker* tl)
272 { tl->add(this, this->final_blocker_); }
276 { return "Hash_task"; }
280 const size_t offset_;
282 unsigned char* const dst_;
283 Task_token* const final_blocker_;
286 // Layout::Relaxation_debug_check methods.
288 // Check that sections and special data are in reset states.
289 // We do not save states for Output_sections and special Output_data.
290 // So we check that they have not assigned any addresses or offsets.
291 // clean_up_after_relaxation simply resets their addresses and offsets.
293 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
294 const Layout::Section_list& sections,
295 const Layout::Data_list& special_outputs,
296 const Layout::Data_list& relax_outputs)
298 for(Layout::Section_list::const_iterator p = sections.begin();
301 gold_assert((*p)->address_and_file_offset_have_reset_values());
303 for(Layout::Data_list::const_iterator p = special_outputs.begin();
304 p != special_outputs.end();
306 gold_assert((*p)->address_and_file_offset_have_reset_values());
308 gold_assert(relax_outputs.empty());
311 // Save information of SECTIONS for checking later.
314 Layout::Relaxation_debug_check::read_sections(
315 const Layout::Section_list& sections)
317 for(Layout::Section_list::const_iterator p = sections.begin();
321 Output_section* os = *p;
323 info.output_section = os;
324 info.address = os->is_address_valid() ? os->address() : 0;
325 info.data_size = os->is_data_size_valid() ? os->data_size() : -1;
326 info.offset = os->is_offset_valid()? os->offset() : -1 ;
327 this->section_infos_.push_back(info);
331 // Verify SECTIONS using previously recorded information.
334 Layout::Relaxation_debug_check::verify_sections(
335 const Layout::Section_list& sections)
338 for(Layout::Section_list::const_iterator p = sections.begin();
342 Output_section* os = *p;
343 uint64_t address = os->is_address_valid() ? os->address() : 0;
344 off_t data_size = os->is_data_size_valid() ? os->data_size() : -1;
345 off_t offset = os->is_offset_valid()? os->offset() : -1 ;
347 if (i >= this->section_infos_.size())
349 gold_fatal("Section_info of %s missing.\n", os->name());
351 const Section_info& info = this->section_infos_[i];
352 if (os != info.output_section)
353 gold_fatal("Section order changed. Expecting %s but see %s\n",
354 info.output_section->name(), os->name());
355 if (address != info.address
356 || data_size != info.data_size
357 || offset != info.offset)
358 gold_fatal("Section %s changed.\n", os->name());
362 // Layout_task_runner methods.
364 // Lay out the sections. This is called after all the input objects
368 Layout_task_runner::run(Workqueue* workqueue, const Task* task)
370 // See if any of the input definitions violate the One Definition Rule.
371 // TODO: if this is too slow, do this as a task, rather than inline.
372 this->symtab_->detect_odr_violations(task, this->options_.output_file_name());
374 Layout* layout = this->layout_;
375 off_t file_size = layout->finalize(this->input_objects_,
380 // Now we know the final size of the output file and we know where
381 // each piece of information goes.
383 if (this->mapfile_ != NULL)
385 this->mapfile_->print_discarded_sections(this->input_objects_);
386 layout->print_to_mapfile(this->mapfile_);
390 if (layout->incremental_base() == NULL)
392 of = new Output_file(parameters->options().output_file_name());
393 if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
394 of->set_is_temporary();
399 of = layout->incremental_base()->output_file();
401 // Apply the incremental relocations for symbols whose values
402 // have changed. We do this before we resize the file and start
403 // writing anything else to it, so that we can read the old
404 // incremental information from the file before (possibly)
406 if (parameters->incremental_update())
407 layout->incremental_base()->apply_incremental_relocs(this->symtab_,
411 of->resize(file_size);
414 // Queue up the final set of tasks.
415 gold::queue_final_tasks(this->options_, this->input_objects_,
416 this->symtab_, layout, workqueue, of);
421 Layout::Layout(int number_of_input_files, Script_options* script_options)
422 : number_of_input_files_(number_of_input_files),
423 script_options_(script_options),
431 unattached_section_list_(),
432 special_output_list_(),
433 relax_output_list_(),
434 section_headers_(NULL),
436 relro_segment_(NULL),
437 interp_segment_(NULL),
439 symtab_section_(NULL),
440 symtab_xindex_(NULL),
441 dynsym_section_(NULL),
442 dynsym_xindex_(NULL),
443 dynamic_section_(NULL),
444 dynamic_symbol_(NULL),
446 eh_frame_section_(NULL),
447 eh_frame_data_(NULL),
448 added_eh_frame_data_(false),
449 eh_frame_hdr_section_(NULL),
450 gdb_index_data_(NULL),
451 build_id_note_(NULL),
455 output_file_size_(-1),
456 have_added_input_section_(false),
457 sections_are_attached_(false),
458 input_requires_executable_stack_(false),
459 input_with_gnu_stack_note_(false),
460 input_without_gnu_stack_note_(false),
461 has_static_tls_(false),
462 any_postprocessing_sections_(false),
463 resized_signatures_(false),
464 have_stabstr_section_(false),
465 section_ordering_specified_(false),
466 unique_segment_for_sections_specified_(false),
467 incremental_inputs_(NULL),
468 record_output_section_data_from_script_(false),
469 script_output_section_data_list_(),
470 segment_states_(NULL),
471 relaxation_debug_check_(NULL),
472 section_order_map_(),
473 section_segment_map_(),
474 input_section_position_(),
475 input_section_glob_(),
476 incremental_base_(NULL),
479 // Make space for more than enough segments for a typical file.
480 // This is just for efficiency--it's OK if we wind up needing more.
481 this->segment_list_.reserve(12);
483 // We expect two unattached Output_data objects: the file header and
484 // the segment headers.
485 this->special_output_list_.reserve(2);
487 // Initialize structure needed for an incremental build.
488 if (parameters->incremental())
489 this->incremental_inputs_ = new Incremental_inputs;
491 // The section name pool is worth optimizing in all cases, because
492 // it is small, but there are often overlaps due to .rel sections.
493 this->namepool_.set_optimize();
496 // For incremental links, record the base file to be modified.
499 Layout::set_incremental_base(Incremental_binary* base)
501 this->incremental_base_ = base;
502 this->free_list_.init(base->output_file()->filesize(), true);
505 // Hash a key we use to look up an output section mapping.
508 Layout::Hash_key::operator()(const Layout::Key& k) const
510 return k.first + k.second.first + k.second.second;
513 // These are the debug sections that are actually used by gdb.
514 // Currently, we've checked versions of gdb up to and including 7.4.
515 // We only check the part of the name that follows ".debug_" or
518 static const char* gdb_sections[] =
521 "addr", // Fission extension
522 // "aranges", // not used by gdb as of 7.4
531 // "pubnames", // not used by gdb as of 7.4
532 // "pubtypes", // not used by gdb as of 7.4
533 // "gnu_pubnames", // Fission extension
534 // "gnu_pubtypes", // Fission extension
540 // This is the minimum set of sections needed for line numbers.
542 static const char* lines_only_debug_sections[] =
545 // "addr", // Fission extension
546 // "aranges", // not used by gdb as of 7.4
555 // "pubnames", // not used by gdb as of 7.4
556 // "pubtypes", // not used by gdb as of 7.4
557 // "gnu_pubnames", // Fission extension
558 // "gnu_pubtypes", // Fission extension
561 "str_offsets", // Fission extension
564 // These sections are the DWARF fast-lookup tables, and are not needed
565 // when building a .gdb_index section.
567 static const char* gdb_fast_lookup_sections[] =
576 // Returns whether the given debug section is in the list of
577 // debug-sections-used-by-some-version-of-gdb. SUFFIX is the
578 // portion of the name following ".debug_" or ".zdebug_".
581 is_gdb_debug_section(const char* suffix)
583 // We can do this faster: binary search or a hashtable. But why bother?
584 for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
585 if (strcmp(suffix, gdb_sections[i]) == 0)
590 // Returns whether the given section is needed for lines-only debugging.
593 is_lines_only_debug_section(const char* suffix)
595 // We can do this faster: binary search or a hashtable. But why bother?
597 i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections);
599 if (strcmp(suffix, lines_only_debug_sections[i]) == 0)
604 // Returns whether the given section is a fast-lookup section that
605 // will not be needed when building a .gdb_index section.
608 is_gdb_fast_lookup_section(const char* suffix)
610 // We can do this faster: binary search or a hashtable. But why bother?
612 i < sizeof(gdb_fast_lookup_sections)/sizeof(*gdb_fast_lookup_sections);
614 if (strcmp(suffix, gdb_fast_lookup_sections[i]) == 0)
619 // Sometimes we compress sections. This is typically done for
620 // sections that are not part of normal program execution (such as
621 // .debug_* sections), and where the readers of these sections know
622 // how to deal with compressed sections. This routine doesn't say for
623 // certain whether we'll compress -- it depends on commandline options
624 // as well -- just whether this section is a candidate for compression.
625 // (The Output_compressed_section class decides whether to compress
626 // a given section, and picks the name of the compressed section.)
629 is_compressible_debug_section(const char* secname)
631 return (is_prefix_of(".debug", secname));
634 // We may see compressed debug sections in input files. Return TRUE
635 // if this is the name of a compressed debug section.
638 is_compressed_debug_section(const char* secname)
640 return (is_prefix_of(".zdebug", secname));
644 corresponding_uncompressed_section_name(std::string secname)
646 gold_assert(secname[0] == '.' && secname[1] == 'z');
647 std::string ret(".");
648 ret.append(secname, 2, std::string::npos);
652 // Whether to include this section in the link.
654 template<int size, bool big_endian>
656 Layout::include_section(Sized_relobj_file<size, big_endian>*, const char* name,
657 const elfcpp::Shdr<size, big_endian>& shdr)
659 if (!parameters->options().relocatable()
660 && (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE))
663 elfcpp::Elf_Word sh_type = shdr.get_sh_type();
665 if ((sh_type >= elfcpp::SHT_LOOS && sh_type <= elfcpp::SHT_HIOS)
666 || (sh_type >= elfcpp::SHT_LOPROC && sh_type <= elfcpp::SHT_HIPROC))
667 return parameters->target().should_include_section(sh_type);
671 case elfcpp::SHT_NULL:
672 case elfcpp::SHT_SYMTAB:
673 case elfcpp::SHT_DYNSYM:
674 case elfcpp::SHT_HASH:
675 case elfcpp::SHT_DYNAMIC:
676 case elfcpp::SHT_SYMTAB_SHNDX:
679 case elfcpp::SHT_STRTAB:
680 // Discard the sections which have special meanings in the ELF
681 // ABI. Keep others (e.g., .stabstr). We could also do this by
682 // checking the sh_link fields of the appropriate sections.
683 return (strcmp(name, ".dynstr") != 0
684 && strcmp(name, ".strtab") != 0
685 && strcmp(name, ".shstrtab") != 0);
687 case elfcpp::SHT_RELA:
688 case elfcpp::SHT_REL:
689 case elfcpp::SHT_GROUP:
690 // If we are emitting relocations these should be handled
692 gold_assert(!parameters->options().relocatable());
695 case elfcpp::SHT_PROGBITS:
696 if (parameters->options().strip_debug()
697 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
699 if (is_debug_info_section(name))
702 if (parameters->options().strip_debug_non_line()
703 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
705 // Debugging sections can only be recognized by name.
706 if (is_prefix_of(".debug_", name)
707 && !is_lines_only_debug_section(name + 7))
709 if (is_prefix_of(".zdebug_", name)
710 && !is_lines_only_debug_section(name + 8))
713 if (parameters->options().strip_debug_gdb()
714 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
716 // Debugging sections can only be recognized by name.
717 if (is_prefix_of(".debug_", name)
718 && !is_gdb_debug_section(name + 7))
720 if (is_prefix_of(".zdebug_", name)
721 && !is_gdb_debug_section(name + 8))
724 if (parameters->options().gdb_index()
725 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
727 // When building .gdb_index, we can strip .debug_pubnames,
728 // .debug_pubtypes, and .debug_aranges sections.
729 if (is_prefix_of(".debug_", name)
730 && is_gdb_fast_lookup_section(name + 7))
732 if (is_prefix_of(".zdebug_", name)
733 && is_gdb_fast_lookup_section(name + 8))
736 if (parameters->options().strip_lto_sections()
737 && !parameters->options().relocatable()
738 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
740 // Ignore LTO sections containing intermediate code.
741 if (is_prefix_of(".gnu.lto_", name))
744 // The GNU linker strips .gnu_debuglink sections, so we do too.
745 // This is a feature used to keep debugging information in
747 if (strcmp(name, ".gnu_debuglink") == 0)
756 // Return an output section named NAME, or NULL if there is none.
759 Layout::find_output_section(const char* name) const
761 for (Section_list::const_iterator p = this->section_list_.begin();
762 p != this->section_list_.end();
764 if (strcmp((*p)->name(), name) == 0)
769 // Return an output segment of type TYPE, with segment flags SET set
770 // and segment flags CLEAR clear. Return NULL if there is none.
773 Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
774 elfcpp::Elf_Word clear) const
776 for (Segment_list::const_iterator p = this->segment_list_.begin();
777 p != this->segment_list_.end();
779 if (static_cast<elfcpp::PT>((*p)->type()) == type
780 && ((*p)->flags() & set) == set
781 && ((*p)->flags() & clear) == 0)
786 // When we put a .ctors or .dtors section with more than one word into
787 // a .init_array or .fini_array section, we need to reverse the words
788 // in the .ctors/.dtors section. This is because .init_array executes
789 // constructors front to back, where .ctors executes them back to
790 // front, and vice-versa for .fini_array/.dtors. Although we do want
791 // to remap .ctors/.dtors into .init_array/.fini_array because it can
792 // be more efficient, we don't want to change the order in which
793 // constructors/destructors are run. This set just keeps track of
794 // these sections which need to be reversed. It is only changed by
795 // Layout::layout. It should be a private member of Layout, but that
796 // would require layout.h to #include object.h to get the definition
798 static Unordered_set<Section_id, Section_id_hash> ctors_sections_in_init_array;
800 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a
801 // .init_array/.fini_array section.
804 Layout::is_ctors_in_init_array(Relobj* relobj, unsigned int shndx) const
806 return (ctors_sections_in_init_array.find(Section_id(relobj, shndx))
807 != ctors_sections_in_init_array.end());
810 // Return the output section to use for section NAME with type TYPE
811 // and section flags FLAGS. NAME must be canonicalized in the string
812 // pool, and NAME_KEY is the key. ORDER is where this should appear
813 // in the output sections. IS_RELRO is true for a relro section.
816 Layout::get_output_section(const char* name, Stringpool::Key name_key,
817 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
818 Output_section_order order, bool is_relro)
820 elfcpp::Elf_Word lookup_type = type;
822 // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and
823 // PREINIT_ARRAY like PROGBITS. This ensures that we combine
824 // .init_array, .fini_array, and .preinit_array sections by name
825 // whatever their type in the input file. We do this because the
826 // types are not always right in the input files.
827 if (lookup_type == elfcpp::SHT_INIT_ARRAY
828 || lookup_type == elfcpp::SHT_FINI_ARRAY
829 || lookup_type == elfcpp::SHT_PREINIT_ARRAY)
830 lookup_type = elfcpp::SHT_PROGBITS;
832 elfcpp::Elf_Xword lookup_flags = flags;
834 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
835 // read-write with read-only sections. Some other ELF linkers do
836 // not do this. FIXME: Perhaps there should be an option
838 lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
840 const Key key(name_key, std::make_pair(lookup_type, lookup_flags));
841 const std::pair<Key, Output_section*> v(key, NULL);
842 std::pair<Section_name_map::iterator, bool> ins(
843 this->section_name_map_.insert(v));
846 return ins.first->second;
849 // This is the first time we've seen this name/type/flags
850 // combination. For compatibility with the GNU linker, we
851 // combine sections with contents and zero flags with sections
852 // with non-zero flags. This is a workaround for cases where
853 // assembler code forgets to set section flags. FIXME: Perhaps
854 // there should be an option to control this.
855 Output_section* os = NULL;
857 if (lookup_type == elfcpp::SHT_PROGBITS)
861 Output_section* same_name = this->find_output_section(name);
862 if (same_name != NULL
863 && (same_name->type() == elfcpp::SHT_PROGBITS
864 || same_name->type() == elfcpp::SHT_INIT_ARRAY
865 || same_name->type() == elfcpp::SHT_FINI_ARRAY
866 || same_name->type() == elfcpp::SHT_PREINIT_ARRAY)
867 && (same_name->flags() & elfcpp::SHF_TLS) == 0)
870 else if ((flags & elfcpp::SHF_TLS) == 0)
872 elfcpp::Elf_Xword zero_flags = 0;
873 const Key zero_key(name_key, std::make_pair(lookup_type,
875 Section_name_map::iterator p =
876 this->section_name_map_.find(zero_key);
877 if (p != this->section_name_map_.end())
883 os = this->make_output_section(name, type, flags, order, is_relro);
885 ins.first->second = os;
890 // Returns TRUE iff NAME (an input section from RELOBJ) will
891 // be mapped to an output section that should be KEPT.
894 Layout::keep_input_section(const Relobj* relobj, const char* name)
896 if (! this->script_options_->saw_sections_clause())
899 Script_sections* ss = this->script_options_->script_sections();
900 const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
901 Output_section** output_section_slot;
902 Script_sections::Section_type script_section_type;
905 name = ss->output_section_name(file_name, name, &output_section_slot,
906 &script_section_type, &keep, true);
907 return name != NULL && keep;
910 // Clear the input section flags that should not be copied to the
914 Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags)
916 // Some flags in the input section should not be automatically
917 // copied to the output section.
918 input_section_flags &= ~ (elfcpp::SHF_INFO_LINK
920 | elfcpp::SHF_COMPRESSED
922 | elfcpp::SHF_STRINGS);
924 // We only clear the SHF_LINK_ORDER flag in for
925 // a non-relocatable link.
926 if (!parameters->options().relocatable())
927 input_section_flags &= ~elfcpp::SHF_LINK_ORDER;
929 return input_section_flags;
932 // Pick the output section to use for section NAME, in input file
933 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
934 // linker created section. IS_INPUT_SECTION is true if we are
935 // choosing an output section for an input section found in a input
936 // file. ORDER is where this section should appear in the output
937 // sections. IS_RELRO is true for a relro section. This will return
938 // NULL if the input section should be discarded. MATCH_INPUT_SPEC
939 // is true if the section name should be matched against input specs
940 // in a linker script.
943 Layout::choose_output_section(const Relobj* relobj, const char* name,
944 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
945 bool is_input_section, Output_section_order order,
946 bool is_relro, bool is_reloc,
947 bool match_input_spec)
949 // We should not see any input sections after we have attached
950 // sections to segments.
951 gold_assert(!is_input_section || !this->sections_are_attached_);
953 flags = this->get_output_section_flags(flags);
955 if (this->script_options_->saw_sections_clause() && !is_reloc)
957 // We are using a SECTIONS clause, so the output section is
958 // chosen based only on the name.
960 Script_sections* ss = this->script_options_->script_sections();
961 const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
962 Output_section** output_section_slot;
963 Script_sections::Section_type script_section_type;
964 const char* orig_name = name;
966 name = ss->output_section_name(file_name, name, &output_section_slot,
967 &script_section_type, &keep,
972 gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' "
973 "because it is not allowed by the "
974 "SECTIONS clause of the linker script"),
976 // The SECTIONS clause says to discard this input section.
980 // We can only handle script section types ST_NONE and ST_NOLOAD.
981 switch (script_section_type)
983 case Script_sections::ST_NONE:
985 case Script_sections::ST_NOLOAD:
986 flags &= elfcpp::SHF_ALLOC;
992 // If this is an orphan section--one not mentioned in the linker
993 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
994 // default processing below.
996 if (output_section_slot != NULL)
998 if (*output_section_slot != NULL)
1000 (*output_section_slot)->update_flags_for_input_section(flags);
1001 return *output_section_slot;
1004 // We don't put sections found in the linker script into
1005 // SECTION_NAME_MAP_. That keeps us from getting confused
1006 // if an orphan section is mapped to a section with the same
1007 // name as one in the linker script.
1009 name = this->namepool_.add(name, false, NULL);
1011 Output_section* os = this->make_output_section(name, type, flags,
1014 os->set_found_in_sections_clause();
1016 // Special handling for NOLOAD sections.
1017 if (script_section_type == Script_sections::ST_NOLOAD)
1019 os->set_is_noload();
1021 // The constructor of Output_section sets addresses of non-ALLOC
1022 // sections to 0 by default. We don't want that for NOLOAD
1023 // sections even if they have no SHF_ALLOC flag.
1024 if ((os->flags() & elfcpp::SHF_ALLOC) == 0
1025 && os->is_address_valid())
1027 gold_assert(os->address() == 0
1028 && !os->is_offset_valid()
1029 && !os->is_data_size_valid());
1030 os->reset_address_and_file_offset();
1034 *output_section_slot = os;
1039 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
1041 size_t len = strlen(name);
1042 std::string uncompressed_name;
1044 // Compressed debug sections should be mapped to the corresponding
1045 // uncompressed section.
1046 if (is_compressed_debug_section(name))
1049 corresponding_uncompressed_section_name(std::string(name, len));
1050 name = uncompressed_name.c_str();
1051 len = uncompressed_name.length();
1054 // Turn NAME from the name of the input section into the name of the
1056 if (is_input_section
1057 && !this->script_options_->saw_sections_clause()
1058 && !parameters->options().relocatable())
1060 const char *orig_name = name;
1061 name = parameters->target().output_section_name(relobj, name, &len);
1063 name = Layout::output_section_name(relobj, orig_name, &len);
1066 Stringpool::Key name_key;
1067 name = this->namepool_.add_with_length(name, len, true, &name_key);
1069 // Find or make the output section. The output section is selected
1070 // based on the section name, type, and flags.
1071 return this->get_output_section(name, name_key, type, flags, order, is_relro);
1074 // For incremental links, record the initial fixed layout of a section
1075 // from the base file, and return a pointer to the Output_section.
1077 template<int size, bool big_endian>
1079 Layout::init_fixed_output_section(const char* name,
1080 elfcpp::Shdr<size, big_endian>& shdr)
1082 unsigned int sh_type = shdr.get_sh_type();
1084 // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY,
1085 // PRE_INIT_ARRAY, and NOTE sections.
1086 // All others will be created from scratch and reallocated.
1087 if (!can_incremental_update(sh_type))
1090 // If we're generating a .gdb_index section, we need to regenerate
1092 if (parameters->options().gdb_index()
1093 && sh_type == elfcpp::SHT_PROGBITS
1094 && strcmp(name, ".gdb_index") == 0)
1097 typename elfcpp::Elf_types<size>::Elf_Addr sh_addr = shdr.get_sh_addr();
1098 typename elfcpp::Elf_types<size>::Elf_Off sh_offset = shdr.get_sh_offset();
1099 typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
1100 typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
1101 typename elfcpp::Elf_types<size>::Elf_WXword sh_addralign =
1102 shdr.get_sh_addralign();
1104 // Make the output section.
1105 Stringpool::Key name_key;
1106 name = this->namepool_.add(name, true, &name_key);
1107 Output_section* os = this->get_output_section(name, name_key, sh_type,
1108 sh_flags, ORDER_INVALID, false);
1109 os->set_fixed_layout(sh_addr, sh_offset, sh_size, sh_addralign);
1110 if (sh_type != elfcpp::SHT_NOBITS)
1111 this->free_list_.remove(sh_offset, sh_offset + sh_size);
1115 // Return the index by which an input section should be ordered. This
1116 // is used to sort some .text sections, for compatibility with GNU ld.
1119 Layout::special_ordering_of_input_section(const char* name)
1121 // The GNU linker has some special handling for some sections that
1122 // wind up in the .text section. Sections that start with these
1123 // prefixes must appear first, and must appear in the order listed
1125 static const char* const text_section_sort[] =
1134 i < sizeof(text_section_sort) / sizeof(text_section_sort[0]);
1136 if (is_prefix_of(text_section_sort[i], name))
1142 // Return the output section to use for input section SHNDX, with name
1143 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
1144 // index of a relocation section which applies to this section, or 0
1145 // if none, or -1U if more than one. RELOC_TYPE is the type of the
1146 // relocation section if there is one. Set *OFF to the offset of this
1147 // input section without the output section. Return NULL if the
1148 // section should be discarded. Set *OFF to -1 if the section
1149 // contents should not be written directly to the output file, but
1150 // will instead receive special handling.
1152 template<int size, bool big_endian>
1154 Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
1155 const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
1156 unsigned int reloc_shndx, unsigned int, off_t* off)
1160 if (!this->include_section(object, name, shdr))
1163 elfcpp::Elf_Word sh_type = shdr.get_sh_type();
1165 // In a relocatable link a grouped section must not be combined with
1166 // any other sections.
1168 if (parameters->options().relocatable()
1169 && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
1171 // Some flags in the input section should not be automatically
1172 // copied to the output section.
1173 elfcpp::Elf_Xword flags = (shdr.get_sh_flags()
1174 & ~ elfcpp::SHF_COMPRESSED);
1175 name = this->namepool_.add(name, true, NULL);
1176 os = this->make_output_section(name, sh_type, flags,
1177 ORDER_INVALID, false);
1181 // Plugins can choose to place one or more subsets of sections in
1182 // unique segments and this is done by mapping these section subsets
1183 // to unique output sections. Check if this section needs to be
1184 // remapped to a unique output section.
1185 Section_segment_map::iterator it
1186 = this->section_segment_map_.find(Const_section_id(object, shndx));
1187 if (it == this->section_segment_map_.end())
1189 os = this->choose_output_section(object, name, sh_type,
1190 shdr.get_sh_flags(), true,
1191 ORDER_INVALID, false, false,
1196 // We know the name of the output section, directly call
1197 // get_output_section here by-passing choose_output_section.
1198 elfcpp::Elf_Xword flags
1199 = this->get_output_section_flags(shdr.get_sh_flags());
1201 const char* os_name = it->second->name;
1202 Stringpool::Key name_key;
1203 os_name = this->namepool_.add(os_name, true, &name_key);
1204 os = this->get_output_section(os_name, name_key, sh_type, flags,
1205 ORDER_INVALID, false);
1206 if (!os->is_unique_segment())
1208 os->set_is_unique_segment();
1209 os->set_extra_segment_flags(it->second->flags);
1210 os->set_segment_alignment(it->second->align);
1217 // By default the GNU linker sorts input sections whose names match
1218 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The
1219 // sections are sorted by name. This is used to implement
1220 // constructor priority ordering. We are compatible. When we put
1221 // .ctor sections in .init_array and .dtor sections in .fini_array,
1222 // we must also sort plain .ctor and .dtor sections.
1223 if (!this->script_options_->saw_sections_clause()
1224 && !parameters->options().relocatable()
1225 && (is_prefix_of(".ctors.", name)
1226 || is_prefix_of(".dtors.", name)
1227 || is_prefix_of(".init_array.", name)
1228 || is_prefix_of(".fini_array.", name)
1229 || (parameters->options().ctors_in_init_array()
1230 && (strcmp(name, ".ctors") == 0
1231 || strcmp(name, ".dtors") == 0))))
1232 os->set_must_sort_attached_input_sections();
1234 // By default the GNU linker sorts some special text sections ahead
1235 // of others. We are compatible.
1236 if (parameters->options().text_reorder()
1237 && !this->script_options_->saw_sections_clause()
1238 && !this->is_section_ordering_specified()
1239 && !parameters->options().relocatable()
1240 && Layout::special_ordering_of_input_section(name) >= 0)
1241 os->set_must_sort_attached_input_sections();
1243 // If this is a .ctors or .ctors.* section being mapped to a
1244 // .init_array section, or a .dtors or .dtors.* section being mapped
1245 // to a .fini_array section, we will need to reverse the words if
1246 // there is more than one. Record this section for later. See
1247 // ctors_sections_in_init_array above.
1248 if (!this->script_options_->saw_sections_clause()
1249 && !parameters->options().relocatable()
1250 && shdr.get_sh_size() > size / 8
1251 && (((strcmp(name, ".ctors") == 0
1252 || is_prefix_of(".ctors.", name))
1253 && strcmp(os->name(), ".init_array") == 0)
1254 || ((strcmp(name, ".dtors") == 0
1255 || is_prefix_of(".dtors.", name))
1256 && strcmp(os->name(), ".fini_array") == 0)))
1257 ctors_sections_in_init_array.insert(Section_id(object, shndx));
1259 // FIXME: Handle SHF_LINK_ORDER somewhere.
1261 elfcpp::Elf_Xword orig_flags = os->flags();
1263 *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
1264 this->script_options_->saw_sections_clause());
1266 // If the flags changed, we may have to change the order.
1267 if ((orig_flags & elfcpp::SHF_ALLOC) != 0)
1269 orig_flags &= (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
1270 elfcpp::Elf_Xword new_flags =
1271 os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
1272 if (orig_flags != new_flags)
1273 os->set_order(this->default_section_order(os, false));
1276 this->have_added_input_section_ = true;
1281 // Maps section SECN to SEGMENT s.
1283 Layout::insert_section_segment_map(Const_section_id secn,
1284 Unique_segment_info *s)
1286 gold_assert(this->unique_segment_for_sections_specified_);
1287 this->section_segment_map_[secn] = s;
1290 // Handle a relocation section when doing a relocatable link.
1292 template<int size, bool big_endian>
1294 Layout::layout_reloc(Sized_relobj_file<size, big_endian>* object,
1296 const elfcpp::Shdr<size, big_endian>& shdr,
1297 Output_section* data_section,
1298 Relocatable_relocs* rr)
1300 gold_assert(parameters->options().relocatable()
1301 || parameters->options().emit_relocs());
1303 int sh_type = shdr.get_sh_type();
1306 if (sh_type == elfcpp::SHT_REL)
1308 else if (sh_type == elfcpp::SHT_RELA)
1312 name += data_section->name();
1314 // In a relocatable link relocs for a grouped section must not be
1315 // combined with other reloc sections.
1317 if (!parameters->options().relocatable()
1318 || (data_section->flags() & elfcpp::SHF_GROUP) == 0)
1319 os = this->choose_output_section(object, name.c_str(), sh_type,
1320 shdr.get_sh_flags(), false,
1321 ORDER_INVALID, false, true, false);
1324 const char* n = this->namepool_.add(name.c_str(), true, NULL);
1325 os = this->make_output_section(n, sh_type, shdr.get_sh_flags(),
1326 ORDER_INVALID, false);
1329 os->set_should_link_to_symtab();
1330 os->set_info_section(data_section);
1332 Output_section_data* posd;
1333 if (sh_type == elfcpp::SHT_REL)
1335 os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
1336 posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
1340 else if (sh_type == elfcpp::SHT_RELA)
1342 os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
1343 posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
1350 os->add_output_section_data(posd);
1351 rr->set_output_data(posd);
1356 // Handle a group section when doing a relocatable link.
1358 template<int size, bool big_endian>
1360 Layout::layout_group(Symbol_table* symtab,
1361 Sized_relobj_file<size, big_endian>* object,
1363 const char* group_section_name,
1364 const char* signature,
1365 const elfcpp::Shdr<size, big_endian>& shdr,
1366 elfcpp::Elf_Word flags,
1367 std::vector<unsigned int>* shndxes)
1369 gold_assert(parameters->options().relocatable());
1370 gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
1371 group_section_name = this->namepool_.add(group_section_name, true, NULL);
1372 Output_section* os = this->make_output_section(group_section_name,
1374 shdr.get_sh_flags(),
1375 ORDER_INVALID, false);
1377 // We need to find a symbol with the signature in the symbol table.
1378 // If we don't find one now, we need to look again later.
1379 Symbol* sym = symtab->lookup(signature, NULL);
1381 os->set_info_symndx(sym);
1384 // Reserve some space to minimize reallocations.
1385 if (this->group_signatures_.empty())
1386 this->group_signatures_.reserve(this->number_of_input_files_ * 16);
1388 // We will wind up using a symbol whose name is the signature.
1389 // So just put the signature in the symbol name pool to save it.
1390 signature = symtab->canonicalize_name(signature);
1391 this->group_signatures_.push_back(Group_signature(os, signature));
1394 os->set_should_link_to_symtab();
1397 section_size_type entry_count =
1398 convert_to_section_size_type(shdr.get_sh_size() / 4);
1399 Output_section_data* posd =
1400 new Output_data_group<size, big_endian>(object, entry_count, flags,
1402 os->add_output_section_data(posd);
1405 // Special GNU handling of sections name .eh_frame. They will
1406 // normally hold exception frame data as defined by the C++ ABI
1407 // (http://codesourcery.com/cxx-abi/).
1409 template<int size, bool big_endian>
1411 Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
1412 const unsigned char* symbols,
1414 const unsigned char* symbol_names,
1415 off_t symbol_names_size,
1417 const elfcpp::Shdr<size, big_endian>& shdr,
1418 unsigned int reloc_shndx, unsigned int reloc_type,
1421 gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS
1422 || shdr.get_sh_type() == elfcpp::SHT_X86_64_UNWIND);
1423 gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
1425 Output_section* os = this->make_eh_frame_section(object);
1429 gold_assert(this->eh_frame_section_ == os);
1431 elfcpp::Elf_Xword orig_flags = os->flags();
1433 Eh_frame::Eh_frame_section_disposition disp =
1434 Eh_frame::EH_UNRECOGNIZED_SECTION;
1435 if (!parameters->incremental())
1437 disp = this->eh_frame_data_->add_ehframe_input_section(object,
1447 if (disp == Eh_frame::EH_OPTIMIZABLE_SECTION)
1449 os->update_flags_for_input_section(shdr.get_sh_flags());
1451 // A writable .eh_frame section is a RELRO section.
1452 if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1453 != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1456 os->set_order(ORDER_RELRO);
1463 if (disp == Eh_frame::EH_END_MARKER_SECTION && !this->added_eh_frame_data_)
1465 // We found the end marker section, so now we can add the set of
1466 // optimized sections to the output section. We need to postpone
1467 // adding this until we've found a section we can optimize so that
1468 // the .eh_frame section in crtbeginT.o winds up at the start of
1469 // the output section.
1470 os->add_output_section_data(this->eh_frame_data_);
1471 this->added_eh_frame_data_ = true;
1474 // We couldn't handle this .eh_frame section for some reason.
1475 // Add it as a normal section.
1476 bool saw_sections_clause = this->script_options_->saw_sections_clause();
1477 *off = os->add_input_section(this, object, shndx, ".eh_frame", shdr,
1478 reloc_shndx, saw_sections_clause);
1479 this->have_added_input_section_ = true;
1481 if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1482 != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1483 os->set_order(this->default_section_order(os, false));
1489 Layout::finalize_eh_frame_section()
1491 // If we never found an end marker section, we need to add the
1492 // optimized eh sections to the output section now.
1493 if (!parameters->incremental()
1494 && this->eh_frame_section_ != NULL
1495 && !this->added_eh_frame_data_)
1497 this->eh_frame_section_->add_output_section_data(this->eh_frame_data_);
1498 this->added_eh_frame_data_ = true;
1502 // Create and return the magic .eh_frame section. Create
1503 // .eh_frame_hdr also if appropriate. OBJECT is the object with the
1504 // input .eh_frame section; it may be NULL.
1507 Layout::make_eh_frame_section(const Relobj* object)
1509 // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than
1511 Output_section* os = this->choose_output_section(object, ".eh_frame",
1512 elfcpp::SHT_PROGBITS,
1513 elfcpp::SHF_ALLOC, false,
1514 ORDER_EHFRAME, false, false,
1519 if (this->eh_frame_section_ == NULL)
1521 this->eh_frame_section_ = os;
1522 this->eh_frame_data_ = new Eh_frame();
1524 // For incremental linking, we do not optimize .eh_frame sections
1525 // or create a .eh_frame_hdr section.
1526 if (parameters->options().eh_frame_hdr() && !parameters->incremental())
1528 Output_section* hdr_os =
1529 this->choose_output_section(NULL, ".eh_frame_hdr",
1530 elfcpp::SHT_PROGBITS,
1531 elfcpp::SHF_ALLOC, false,
1532 ORDER_EHFRAME, false, false,
1537 Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
1538 this->eh_frame_data_);
1539 hdr_os->add_output_section_data(hdr_posd);
1541 hdr_os->set_after_input_sections();
1543 if (!this->script_options_->saw_phdrs_clause())
1545 Output_segment* hdr_oseg;
1546 hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
1548 hdr_oseg->add_output_section_to_nonload(hdr_os,
1552 this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
1560 // Add an exception frame for a PLT. This is called from target code.
1563 Layout::add_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data,
1564 size_t cie_length, const unsigned char* fde_data,
1567 if (parameters->incremental())
1569 // FIXME: Maybe this could work some day....
1572 Output_section* os = this->make_eh_frame_section(NULL);
1575 this->eh_frame_data_->add_ehframe_for_plt(plt, cie_data, cie_length,
1576 fde_data, fde_length);
1577 if (!this->added_eh_frame_data_)
1579 os->add_output_section_data(this->eh_frame_data_);
1580 this->added_eh_frame_data_ = true;
1584 // Scan a .debug_info or .debug_types section, and add summary
1585 // information to the .gdb_index section.
1587 template<int size, bool big_endian>
1589 Layout::add_to_gdb_index(bool is_type_unit,
1590 Sized_relobj<size, big_endian>* object,
1591 const unsigned char* symbols,
1594 unsigned int reloc_shndx,
1595 unsigned int reloc_type)
1597 if (this->gdb_index_data_ == NULL)
1599 Output_section* os = this->choose_output_section(NULL, ".gdb_index",
1600 elfcpp::SHT_PROGBITS, 0,
1601 false, ORDER_INVALID,
1602 false, false, false);
1606 this->gdb_index_data_ = new Gdb_index(os);
1607 os->add_output_section_data(this->gdb_index_data_);
1608 os->set_after_input_sections();
1611 this->gdb_index_data_->scan_debug_info(is_type_unit, object, symbols,
1612 symbols_size, shndx, reloc_shndx,
1616 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1617 // the output section.
1620 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
1621 elfcpp::Elf_Xword flags,
1622 Output_section_data* posd,
1623 Output_section_order order, bool is_relro)
1625 Output_section* os = this->choose_output_section(NULL, name, type, flags,
1626 false, order, is_relro,
1629 os->add_output_section_data(posd);
1633 // Map section flags to segment flags.
1636 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
1638 elfcpp::Elf_Word ret = elfcpp::PF_R;
1639 if ((flags & elfcpp::SHF_WRITE) != 0)
1640 ret |= elfcpp::PF_W;
1641 if ((flags & elfcpp::SHF_EXECINSTR) != 0)
1642 ret |= elfcpp::PF_X;
1646 // Make a new Output_section, and attach it to segments as
1647 // appropriate. ORDER is the order in which this section should
1648 // appear in the output segment. IS_RELRO is true if this is a relro
1649 // (read-only after relocations) section.
1652 Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
1653 elfcpp::Elf_Xword flags,
1654 Output_section_order order, bool is_relro)
1657 if ((flags & elfcpp::SHF_ALLOC) == 0
1658 && strcmp(parameters->options().compress_debug_sections(), "none") != 0
1659 && is_compressible_debug_section(name))
1660 os = new Output_compressed_section(¶meters->options(), name, type,
1662 else if ((flags & elfcpp::SHF_ALLOC) == 0
1663 && parameters->options().strip_debug_non_line()
1664 && strcmp(".debug_abbrev", name) == 0)
1666 os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
1668 if (this->debug_info_)
1669 this->debug_info_->set_abbreviations(this->debug_abbrev_);
1671 else if ((flags & elfcpp::SHF_ALLOC) == 0
1672 && parameters->options().strip_debug_non_line()
1673 && strcmp(".debug_info", name) == 0)
1675 os = this->debug_info_ = new Output_reduced_debug_info_section(
1677 if (this->debug_abbrev_)
1678 this->debug_info_->set_abbreviations(this->debug_abbrev_);
1682 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1683 // not have correct section types. Force them here.
1684 if (type == elfcpp::SHT_PROGBITS)
1686 if (is_prefix_of(".init_array", name))
1687 type = elfcpp::SHT_INIT_ARRAY;
1688 else if (is_prefix_of(".preinit_array", name))
1689 type = elfcpp::SHT_PREINIT_ARRAY;
1690 else if (is_prefix_of(".fini_array", name))
1691 type = elfcpp::SHT_FINI_ARRAY;
1694 // FIXME: const_cast is ugly.
1695 Target* target = const_cast<Target*>(¶meters->target());
1696 os = target->make_output_section(name, type, flags);
1699 // With -z relro, we have to recognize the special sections by name.
1700 // There is no other way.
1701 bool is_relro_local = false;
1702 if (!this->script_options_->saw_sections_clause()
1703 && parameters->options().relro()
1704 && (flags & elfcpp::SHF_ALLOC) != 0
1705 && (flags & elfcpp::SHF_WRITE) != 0)
1707 if (type == elfcpp::SHT_PROGBITS)
1709 if ((flags & elfcpp::SHF_TLS) != 0)
1711 else if (strcmp(name, ".data.rel.ro") == 0)
1713 else if (strcmp(name, ".data.rel.ro.local") == 0)
1716 is_relro_local = true;
1718 else if (strcmp(name, ".ctors") == 0
1719 || strcmp(name, ".dtors") == 0
1720 || strcmp(name, ".jcr") == 0)
1723 else if (type == elfcpp::SHT_INIT_ARRAY
1724 || type == elfcpp::SHT_FINI_ARRAY
1725 || type == elfcpp::SHT_PREINIT_ARRAY)
1732 if (order == ORDER_INVALID && (flags & elfcpp::SHF_ALLOC) != 0)
1733 order = this->default_section_order(os, is_relro_local);
1735 os->set_order(order);
1737 parameters->target().new_output_section(os);
1739 this->section_list_.push_back(os);
1741 // The GNU linker by default sorts some sections by priority, so we
1742 // do the same. We need to know that this might happen before we
1743 // attach any input sections.
1744 if (!this->script_options_->saw_sections_clause()
1745 && !parameters->options().relocatable()
1746 && (strcmp(name, ".init_array") == 0
1747 || strcmp(name, ".fini_array") == 0
1748 || (!parameters->options().ctors_in_init_array()
1749 && (strcmp(name, ".ctors") == 0
1750 || strcmp(name, ".dtors") == 0))))
1751 os->set_may_sort_attached_input_sections();
1753 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1754 // sections before other .text sections. We are compatible. We
1755 // need to know that this might happen before we attach any input
1757 if (parameters->options().text_reorder()
1758 && !this->script_options_->saw_sections_clause()
1759 && !this->is_section_ordering_specified()
1760 && !parameters->options().relocatable()
1761 && strcmp(name, ".text") == 0)
1762 os->set_may_sort_attached_input_sections();
1764 // GNU linker sorts section by name with --sort-section=name.
1765 if (strcmp(parameters->options().sort_section(), "name") == 0)
1766 os->set_must_sort_attached_input_sections();
1768 // Check for .stab*str sections, as .stab* sections need to link to
1770 if (type == elfcpp::SHT_STRTAB
1771 && !this->have_stabstr_section_
1772 && strncmp(name, ".stab", 5) == 0
1773 && strcmp(name + strlen(name) - 3, "str") == 0)
1774 this->have_stabstr_section_ = true;
1776 // During a full incremental link, we add patch space to most
1777 // PROGBITS and NOBITS sections. Flag those that may be
1778 // arbitrarily padded.
1779 if ((type == elfcpp::SHT_PROGBITS || type == elfcpp::SHT_NOBITS)
1780 && order != ORDER_INTERP
1781 && order != ORDER_INIT
1782 && order != ORDER_PLT
1783 && order != ORDER_FINI
1784 && order != ORDER_RELRO_LAST
1785 && order != ORDER_NON_RELRO_FIRST
1786 && strcmp(name, ".eh_frame") != 0
1787 && strcmp(name, ".ctors") != 0
1788 && strcmp(name, ".dtors") != 0
1789 && strcmp(name, ".jcr") != 0)
1791 os->set_is_patch_space_allowed();
1793 // Certain sections require "holes" to be filled with
1794 // specific fill patterns. These fill patterns may have
1795 // a minimum size, so we must prevent allocations from the
1796 // free list that leave a hole smaller than the minimum.
1797 if (strcmp(name, ".debug_info") == 0)
1798 os->set_free_space_fill(new Output_fill_debug_info(false));
1799 else if (strcmp(name, ".debug_types") == 0)
1800 os->set_free_space_fill(new Output_fill_debug_info(true));
1801 else if (strcmp(name, ".debug_line") == 0)
1802 os->set_free_space_fill(new Output_fill_debug_line());
1805 // If we have already attached the sections to segments, then we
1806 // need to attach this one now. This happens for sections created
1807 // directly by the linker.
1808 if (this->sections_are_attached_)
1809 this->attach_section_to_segment(¶meters->target(), os);
1814 // Return the default order in which a section should be placed in an
1815 // output segment. This function captures a lot of the ideas in
1816 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1817 // linker created section is normally set when the section is created;
1818 // this function is used for input sections.
1820 Output_section_order
1821 Layout::default_section_order(Output_section* os, bool is_relro_local)
1823 gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
1824 bool is_write = (os->flags() & elfcpp::SHF_WRITE) != 0;
1825 bool is_execinstr = (os->flags() & elfcpp::SHF_EXECINSTR) != 0;
1826 bool is_bss = false;
1831 case elfcpp::SHT_PROGBITS:
1833 case elfcpp::SHT_NOBITS:
1836 case elfcpp::SHT_RELA:
1837 case elfcpp::SHT_REL:
1839 return ORDER_DYNAMIC_RELOCS;
1841 case elfcpp::SHT_HASH:
1842 case elfcpp::SHT_DYNAMIC:
1843 case elfcpp::SHT_SHLIB:
1844 case elfcpp::SHT_DYNSYM:
1845 case elfcpp::SHT_GNU_HASH:
1846 case elfcpp::SHT_GNU_verdef:
1847 case elfcpp::SHT_GNU_verneed:
1848 case elfcpp::SHT_GNU_versym:
1850 return ORDER_DYNAMIC_LINKER;
1852 case elfcpp::SHT_NOTE:
1853 return is_write ? ORDER_RW_NOTE : ORDER_RO_NOTE;
1856 if ((os->flags() & elfcpp::SHF_TLS) != 0)
1857 return is_bss ? ORDER_TLS_BSS : ORDER_TLS_DATA;
1859 if (!is_bss && !is_write)
1863 if (strcmp(os->name(), ".init") == 0)
1865 else if (strcmp(os->name(), ".fini") == 0)
1868 return is_execinstr ? ORDER_TEXT : ORDER_READONLY;
1872 return is_relro_local ? ORDER_RELRO_LOCAL : ORDER_RELRO;
1874 if (os->is_small_section())
1875 return is_bss ? ORDER_SMALL_BSS : ORDER_SMALL_DATA;
1876 if (os->is_large_section())
1877 return is_bss ? ORDER_LARGE_BSS : ORDER_LARGE_DATA;
1879 return is_bss ? ORDER_BSS : ORDER_DATA;
1882 // Attach output sections to segments. This is called after we have
1883 // seen all the input sections.
1886 Layout::attach_sections_to_segments(const Target* target)
1888 for (Section_list::iterator p = this->section_list_.begin();
1889 p != this->section_list_.end();
1891 this->attach_section_to_segment(target, *p);
1893 this->sections_are_attached_ = true;
1896 // Attach an output section to a segment.
1899 Layout::attach_section_to_segment(const Target* target, Output_section* os)
1901 if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
1902 this->unattached_section_list_.push_back(os);
1904 this->attach_allocated_section_to_segment(target, os);
1907 // Attach an allocated output section to a segment.
1910 Layout::attach_allocated_section_to_segment(const Target* target,
1913 elfcpp::Elf_Xword flags = os->flags();
1914 gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
1916 if (parameters->options().relocatable())
1919 // If we have a SECTIONS clause, we can't handle the attachment to
1920 // segments until after we've seen all the sections.
1921 if (this->script_options_->saw_sections_clause())
1924 gold_assert(!this->script_options_->saw_phdrs_clause());
1926 // This output section goes into a PT_LOAD segment.
1928 elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
1930 // If this output section's segment has extra flags that need to be set,
1931 // coming from a linker plugin, do that.
1932 seg_flags |= os->extra_segment_flags();
1934 // Check for --section-start.
1936 bool is_address_set = parameters->options().section_start(os->name(), &addr);
1938 // In general the only thing we really care about for PT_LOAD
1939 // segments is whether or not they are writable or executable,
1940 // so that is how we search for them.
1941 // Large data sections also go into their own PT_LOAD segment.
1942 // People who need segments sorted on some other basis will
1943 // have to use a linker script.
1945 Segment_list::const_iterator p;
1946 if (!os->is_unique_segment())
1948 for (p = this->segment_list_.begin();
1949 p != this->segment_list_.end();
1952 if ((*p)->type() != elfcpp::PT_LOAD)
1954 if ((*p)->is_unique_segment())
1956 if (!parameters->options().omagic()
1957 && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
1959 if ((target->isolate_execinstr() || parameters->options().rosegment())
1960 && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
1962 // If -Tbss was specified, we need to separate the data and BSS
1964 if (parameters->options().user_set_Tbss())
1966 if ((os->type() == elfcpp::SHT_NOBITS)
1967 == (*p)->has_any_data_sections())
1970 if (os->is_large_data_section() && !(*p)->is_large_data_segment())
1975 if ((*p)->are_addresses_set())
1978 (*p)->add_initial_output_data(os);
1979 (*p)->update_flags_for_output_section(seg_flags);
1980 (*p)->set_addresses(addr, addr);
1984 (*p)->add_output_section_to_load(this, os, seg_flags);
1989 if (p == this->segment_list_.end()
1990 || os->is_unique_segment())
1992 Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
1994 if (os->is_large_data_section())
1995 oseg->set_is_large_data_segment();
1996 oseg->add_output_section_to_load(this, os, seg_flags);
1998 oseg->set_addresses(addr, addr);
1999 // Check if segment should be marked unique. For segments marked
2000 // unique by linker plugins, set the new alignment if specified.
2001 if (os->is_unique_segment())
2003 oseg->set_is_unique_segment();
2004 if (os->segment_alignment() != 0)
2005 oseg->set_minimum_p_align(os->segment_alignment());
2009 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
2011 if (os->type() == elfcpp::SHT_NOTE)
2013 // See if we already have an equivalent PT_NOTE segment.
2014 for (p = this->segment_list_.begin();
2015 p != segment_list_.end();
2018 if ((*p)->type() == elfcpp::PT_NOTE
2019 && (((*p)->flags() & elfcpp::PF_W)
2020 == (seg_flags & elfcpp::PF_W)))
2022 (*p)->add_output_section_to_nonload(os, seg_flags);
2027 if (p == this->segment_list_.end())
2029 Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
2031 oseg->add_output_section_to_nonload(os, seg_flags);
2035 // If we see a loadable SHF_TLS section, we create a PT_TLS
2036 // segment. There can only be one such segment.
2037 if ((flags & elfcpp::SHF_TLS) != 0)
2039 if (this->tls_segment_ == NULL)
2040 this->make_output_segment(elfcpp::PT_TLS, seg_flags);
2041 this->tls_segment_->add_output_section_to_nonload(os, seg_flags);
2044 // If -z relro is in effect, and we see a relro section, we create a
2045 // PT_GNU_RELRO segment. There can only be one such segment.
2046 if (os->is_relro() && parameters->options().relro())
2048 gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
2049 if (this->relro_segment_ == NULL)
2050 this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
2051 this->relro_segment_->add_output_section_to_nonload(os, seg_flags);
2054 // If we see a section named .interp, put it into a PT_INTERP
2055 // segment. This seems broken to me, but this is what GNU ld does,
2056 // and glibc expects it.
2057 if (strcmp(os->name(), ".interp") == 0
2058 && !this->script_options_->saw_phdrs_clause())
2060 if (this->interp_segment_ == NULL)
2061 this->make_output_segment(elfcpp::PT_INTERP, seg_flags);
2063 gold_warning(_("multiple '.interp' sections in input files "
2064 "may cause confusing PT_INTERP segment"));
2065 this->interp_segment_->add_output_section_to_nonload(os, seg_flags);
2069 // Make an output section for a script.
2072 Layout::make_output_section_for_script(
2074 Script_sections::Section_type section_type)
2076 name = this->namepool_.add(name, false, NULL);
2077 elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC;
2078 if (section_type == Script_sections::ST_NOLOAD)
2080 Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
2081 sh_flags, ORDER_INVALID,
2083 os->set_found_in_sections_clause();
2084 if (section_type == Script_sections::ST_NOLOAD)
2085 os->set_is_noload();
2089 // Return the number of segments we expect to see.
2092 Layout::expected_segment_count() const
2094 size_t ret = this->segment_list_.size();
2096 // If we didn't see a SECTIONS clause in a linker script, we should
2097 // already have the complete list of segments. Otherwise we ask the
2098 // SECTIONS clause how many segments it expects, and add in the ones
2099 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
2101 if (!this->script_options_->saw_sections_clause())
2105 const Script_sections* ss = this->script_options_->script_sections();
2106 return ret + ss->expected_segment_count(this);
2110 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
2111 // is whether we saw a .note.GNU-stack section in the object file.
2112 // GNU_STACK_FLAGS is the section flags. The flags give the
2113 // protection required for stack memory. We record this in an
2114 // executable as a PT_GNU_STACK segment. If an object file does not
2115 // have a .note.GNU-stack segment, we must assume that it is an old
2116 // object. On some targets that will force an executable stack.
2119 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags,
2122 if (!seen_gnu_stack)
2124 this->input_without_gnu_stack_note_ = true;
2125 if (parameters->options().warn_execstack()
2126 && parameters->target().is_default_stack_executable())
2127 gold_warning(_("%s: missing .note.GNU-stack section"
2128 " implies executable stack"),
2129 obj->name().c_str());
2133 this->input_with_gnu_stack_note_ = true;
2134 if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
2136 this->input_requires_executable_stack_ = true;
2137 if (parameters->options().warn_execstack())
2138 gold_warning(_("%s: requires executable stack"),
2139 obj->name().c_str());
2144 // Create automatic note sections.
2147 Layout::create_notes()
2149 this->create_gold_note();
2150 this->create_stack_segment();
2151 this->create_build_id();
2154 // Create the dynamic sections which are needed before we read the
2158 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
2160 if (parameters->doing_static_link())
2163 this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
2164 elfcpp::SHT_DYNAMIC,
2166 | elfcpp::SHF_WRITE),
2168 true, false, false);
2170 // A linker script may discard .dynamic, so check for NULL.
2171 if (this->dynamic_section_ != NULL)
2173 this->dynamic_symbol_ =
2174 symtab->define_in_output_data("_DYNAMIC", NULL,
2175 Symbol_table::PREDEFINED,
2176 this->dynamic_section_, 0, 0,
2177 elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
2178 elfcpp::STV_HIDDEN, 0, false, false);
2180 this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_);
2182 this->dynamic_section_->add_output_section_data(this->dynamic_data_);
2186 // For each output section whose name can be represented as C symbol,
2187 // define __start and __stop symbols for the section. This is a GNU
2191 Layout::define_section_symbols(Symbol_table* symtab)
2193 for (Section_list::const_iterator p = this->section_list_.begin();
2194 p != this->section_list_.end();
2197 const char* const name = (*p)->name();
2198 if (is_cident(name))
2200 const std::string name_string(name);
2201 const std::string start_name(cident_section_start_prefix
2203 const std::string stop_name(cident_section_stop_prefix
2206 symtab->define_in_output_data(start_name.c_str(),
2208 Symbol_table::PREDEFINED,
2214 elfcpp::STV_DEFAULT,
2216 false, // offset_is_from_end
2217 true); // only_if_ref
2219 symtab->define_in_output_data(stop_name.c_str(),
2221 Symbol_table::PREDEFINED,
2227 elfcpp::STV_DEFAULT,
2229 true, // offset_is_from_end
2230 true); // only_if_ref
2235 // Define symbols for group signatures.
2238 Layout::define_group_signatures(Symbol_table* symtab)
2240 for (Group_signatures::iterator p = this->group_signatures_.begin();
2241 p != this->group_signatures_.end();
2244 Symbol* sym = symtab->lookup(p->signature, NULL);
2246 p->section->set_info_symndx(sym);
2249 // Force the name of the group section to the group
2250 // signature, and use the group's section symbol as the
2251 // signature symbol.
2252 if (strcmp(p->section->name(), p->signature) != 0)
2254 const char* name = this->namepool_.add(p->signature,
2256 p->section->set_name(name);
2258 p->section->set_needs_symtab_index();
2259 p->section->set_info_section_symndx(p->section);
2263 this->group_signatures_.clear();
2266 // Find the first read-only PT_LOAD segment, creating one if
2270 Layout::find_first_load_seg(const Target* target)
2272 Output_segment* best = NULL;
2273 for (Segment_list::const_iterator p = this->segment_list_.begin();
2274 p != this->segment_list_.end();
2277 if ((*p)->type() == elfcpp::PT_LOAD
2278 && ((*p)->flags() & elfcpp::PF_R) != 0
2279 && (parameters->options().omagic()
2280 || ((*p)->flags() & elfcpp::PF_W) == 0)
2281 && (!target->isolate_execinstr()
2282 || ((*p)->flags() & elfcpp::PF_X) == 0))
2284 if (best == NULL || this->segment_precedes(*p, best))
2291 gold_assert(!this->script_options_->saw_phdrs_clause());
2293 Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
2298 // Save states of all current output segments. Store saved states
2299 // in SEGMENT_STATES.
2302 Layout::save_segments(Segment_states* segment_states)
2304 for (Segment_list::const_iterator p = this->segment_list_.begin();
2305 p != this->segment_list_.end();
2308 Output_segment* segment = *p;
2310 Output_segment* copy = new Output_segment(*segment);
2311 (*segment_states)[segment] = copy;
2315 // Restore states of output segments and delete any segment not found in
2319 Layout::restore_segments(const Segment_states* segment_states)
2321 // Go through the segment list and remove any segment added in the
2323 this->tls_segment_ = NULL;
2324 this->relro_segment_ = NULL;
2325 Segment_list::iterator list_iter = this->segment_list_.begin();
2326 while (list_iter != this->segment_list_.end())
2328 Output_segment* segment = *list_iter;
2329 Segment_states::const_iterator states_iter =
2330 segment_states->find(segment);
2331 if (states_iter != segment_states->end())
2333 const Output_segment* copy = states_iter->second;
2334 // Shallow copy to restore states.
2337 // Also fix up TLS and RELRO segment pointers as appropriate.
2338 if (segment->type() == elfcpp::PT_TLS)
2339 this->tls_segment_ = segment;
2340 else if (segment->type() == elfcpp::PT_GNU_RELRO)
2341 this->relro_segment_ = segment;
2347 list_iter = this->segment_list_.erase(list_iter);
2348 // This is a segment created during section layout. It should be
2349 // safe to remove it since we should have removed all pointers to it.
2355 // Clean up after relaxation so that sections can be laid out again.
2358 Layout::clean_up_after_relaxation()
2360 // Restore the segments to point state just prior to the relaxation loop.
2361 Script_sections* script_section = this->script_options_->script_sections();
2362 script_section->release_segments();
2363 this->restore_segments(this->segment_states_);
2365 // Reset section addresses and file offsets
2366 for (Section_list::iterator p = this->section_list_.begin();
2367 p != this->section_list_.end();
2370 (*p)->restore_states();
2372 // If an input section changes size because of relaxation,
2373 // we need to adjust the section offsets of all input sections.
2374 // after such a section.
2375 if ((*p)->section_offsets_need_adjustment())
2376 (*p)->adjust_section_offsets();
2378 (*p)->reset_address_and_file_offset();
2381 // Reset special output object address and file offsets.
2382 for (Data_list::iterator p = this->special_output_list_.begin();
2383 p != this->special_output_list_.end();
2385 (*p)->reset_address_and_file_offset();
2387 // A linker script may have created some output section data objects.
2388 // They are useless now.
2389 for (Output_section_data_list::const_iterator p =
2390 this->script_output_section_data_list_.begin();
2391 p != this->script_output_section_data_list_.end();
2394 this->script_output_section_data_list_.clear();
2396 // Special-case fill output objects are recreated each time through
2397 // the relaxation loop.
2398 this->reset_relax_output();
2402 Layout::reset_relax_output()
2404 for (Data_list::const_iterator p = this->relax_output_list_.begin();
2405 p != this->relax_output_list_.end();
2408 this->relax_output_list_.clear();
2411 // Prepare for relaxation.
2414 Layout::prepare_for_relaxation()
2416 // Create an relaxation debug check if in debugging mode.
2417 if (is_debugging_enabled(DEBUG_RELAXATION))
2418 this->relaxation_debug_check_ = new Relaxation_debug_check();
2420 // Save segment states.
2421 this->segment_states_ = new Segment_states();
2422 this->save_segments(this->segment_states_);
2424 for(Section_list::const_iterator p = this->section_list_.begin();
2425 p != this->section_list_.end();
2427 (*p)->save_states();
2429 if (is_debugging_enabled(DEBUG_RELAXATION))
2430 this->relaxation_debug_check_->check_output_data_for_reset_values(
2431 this->section_list_, this->special_output_list_,
2432 this->relax_output_list_);
2434 // Also enable recording of output section data from scripts.
2435 this->record_output_section_data_from_script_ = true;
2438 // If the user set the address of the text segment, that may not be
2439 // compatible with putting the segment headers and file headers into
2440 // that segment. For isolate_execinstr() targets, it's the rodata
2441 // segment rather than text where we might put the headers.
2443 load_seg_unusable_for_headers(const Target* target)
2445 const General_options& options = parameters->options();
2446 if (target->isolate_execinstr())
2447 return (options.user_set_Trodata_segment()
2448 && options.Trodata_segment() % target->abi_pagesize() != 0);
2450 return (options.user_set_Ttext()
2451 && options.Ttext() % target->abi_pagesize() != 0);
2454 // Relaxation loop body: If target has no relaxation, this runs only once
2455 // Otherwise, the target relaxation hook is called at the end of
2456 // each iteration. If the hook returns true, it means re-layout of
2457 // section is required.
2459 // The number of segments created by a linking script without a PHDRS
2460 // clause may be affected by section sizes and alignments. There is
2461 // a remote chance that relaxation causes different number of PT_LOAD
2462 // segments are created and sections are attached to different segments.
2463 // Therefore, we always throw away all segments created during section
2464 // layout. In order to be able to restart the section layout, we keep
2465 // a copy of the segment list right before the relaxation loop and use
2466 // that to restore the segments.
2468 // PASS is the current relaxation pass number.
2469 // SYMTAB is a symbol table.
2470 // PLOAD_SEG is the address of a pointer for the load segment.
2471 // PHDR_SEG is a pointer to the PHDR segment.
2472 // SEGMENT_HEADERS points to the output segment header.
2473 // FILE_HEADER points to the output file header.
2474 // PSHNDX is the address to store the output section index.
2477 Layout::relaxation_loop_body(
2480 Symbol_table* symtab,
2481 Output_segment** pload_seg,
2482 Output_segment* phdr_seg,
2483 Output_segment_headers* segment_headers,
2484 Output_file_header* file_header,
2485 unsigned int* pshndx)
2487 // If this is not the first iteration, we need to clean up after
2488 // relaxation so that we can lay out the sections again.
2490 this->clean_up_after_relaxation();
2492 // If there is a SECTIONS clause, put all the input sections into
2493 // the required order.
2494 Output_segment* load_seg;
2495 if (this->script_options_->saw_sections_clause())
2496 load_seg = this->set_section_addresses_from_script(symtab);
2497 else if (parameters->options().relocatable())
2500 load_seg = this->find_first_load_seg(target);
2502 if (parameters->options().oformat_enum()
2503 != General_options::OBJECT_FORMAT_ELF)
2506 if (load_seg_unusable_for_headers(target))
2512 gold_assert(phdr_seg == NULL
2514 || this->script_options_->saw_sections_clause());
2516 // If the address of the load segment we found has been set by
2517 // --section-start rather than by a script, then adjust the VMA and
2518 // LMA downward if possible to include the file and section headers.
2519 uint64_t header_gap = 0;
2520 if (load_seg != NULL
2521 && load_seg->are_addresses_set()
2522 && !this->script_options_->saw_sections_clause()
2523 && !parameters->options().relocatable())
2525 file_header->finalize_data_size();
2526 segment_headers->finalize_data_size();
2527 size_t sizeof_headers = (file_header->data_size()
2528 + segment_headers->data_size());
2529 const uint64_t abi_pagesize = target->abi_pagesize();
2530 uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers;
2531 hdr_paddr &= ~(abi_pagesize - 1);
2532 uint64_t subtract = load_seg->paddr() - hdr_paddr;
2533 if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract)
2537 load_seg->set_addresses(load_seg->vaddr() - subtract,
2538 load_seg->paddr() - subtract);
2539 header_gap = subtract - sizeof_headers;
2543 // Lay out the segment headers.
2544 if (!parameters->options().relocatable())
2546 gold_assert(segment_headers != NULL);
2547 if (header_gap != 0 && load_seg != NULL)
2549 Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1);
2550 load_seg->add_initial_output_data(z);
2552 if (load_seg != NULL)
2553 load_seg->add_initial_output_data(segment_headers);
2554 if (phdr_seg != NULL)
2555 phdr_seg->add_initial_output_data(segment_headers);
2558 // Lay out the file header.
2559 if (load_seg != NULL)
2560 load_seg->add_initial_output_data(file_header);
2562 if (this->script_options_->saw_phdrs_clause()
2563 && !parameters->options().relocatable())
2565 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2566 // clause in a linker script.
2567 Script_sections* ss = this->script_options_->script_sections();
2568 ss->put_headers_in_phdrs(file_header, segment_headers);
2571 // We set the output section indexes in set_segment_offsets and
2572 // set_section_indexes.
2575 // Set the file offsets of all the segments, and all the sections
2578 if (!parameters->options().relocatable())
2579 off = this->set_segment_offsets(target, load_seg, pshndx);
2581 off = this->set_relocatable_section_offsets(file_header, pshndx);
2583 // Verify that the dummy relaxation does not change anything.
2584 if (is_debugging_enabled(DEBUG_RELAXATION))
2587 this->relaxation_debug_check_->read_sections(this->section_list_);
2589 this->relaxation_debug_check_->verify_sections(this->section_list_);
2592 *pload_seg = load_seg;
2596 // Search the list of patterns and find the position of the given section
2597 // name in the output section. If the section name matches a glob
2598 // pattern and a non-glob name, then the non-glob position takes
2599 // precedence. Return 0 if no match is found.
2602 Layout::find_section_order_index(const std::string& section_name)
2604 Unordered_map<std::string, unsigned int>::iterator map_it;
2605 map_it = this->input_section_position_.find(section_name);
2606 if (map_it != this->input_section_position_.end())
2607 return map_it->second;
2609 // Absolute match failed. Linear search the glob patterns.
2610 std::vector<std::string>::iterator it;
2611 for (it = this->input_section_glob_.begin();
2612 it != this->input_section_glob_.end();
2615 if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0)
2617 map_it = this->input_section_position_.find(*it);
2618 gold_assert(map_it != this->input_section_position_.end());
2619 return map_it->second;
2625 // Read the sequence of input sections from the file specified with
2626 // option --section-ordering-file.
2629 Layout::read_layout_from_file()
2631 const char* filename = parameters->options().section_ordering_file();
2637 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2638 filename, strerror(errno));
2640 std::getline(in, line); // this chops off the trailing \n, if any
2641 unsigned int position = 1;
2642 this->set_section_ordering_specified();
2646 if (!line.empty() && line[line.length() - 1] == '\r') // Windows
2647 line.resize(line.length() - 1);
2648 // Ignore comments, beginning with '#'
2651 std::getline(in, line);
2654 this->input_section_position_[line] = position;
2655 // Store all glob patterns in a vector.
2656 if (is_wildcard_string(line.c_str()))
2657 this->input_section_glob_.push_back(line);
2659 std::getline(in, line);
2663 // Finalize the layout. When this is called, we have created all the
2664 // output sections and all the output segments which are based on
2665 // input sections. We have several things to do, and we have to do
2666 // them in the right order, so that we get the right results correctly
2669 // 1) Finalize the list of output segments and create the segment
2672 // 2) Finalize the dynamic symbol table and associated sections.
2674 // 3) Determine the final file offset of all the output segments.
2676 // 4) Determine the final file offset of all the SHF_ALLOC output
2679 // 5) Create the symbol table sections and the section name table
2682 // 6) Finalize the symbol table: set symbol values to their final
2683 // value and make a final determination of which symbols are going
2684 // into the output symbol table.
2686 // 7) Create the section table header.
2688 // 8) Determine the final file offset of all the output sections which
2689 // are not SHF_ALLOC, including the section table header.
2691 // 9) Finalize the ELF file header.
2693 // This function returns the size of the output file.
2696 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
2697 Target* target, const Task* task)
2699 target->finalize_sections(this, input_objects, symtab);
2701 this->count_local_symbols(task, input_objects);
2703 this->link_stabs_sections();
2705 Output_segment* phdr_seg = NULL;
2706 if (!parameters->options().relocatable() && !parameters->doing_static_link())
2708 // There was a dynamic object in the link. We need to create
2709 // some information for the dynamic linker.
2711 // Create the PT_PHDR segment which will hold the program
2713 if (!this->script_options_->saw_phdrs_clause())
2714 phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
2716 // Create the dynamic symbol table, including the hash table.
2717 Output_section* dynstr;
2718 std::vector<Symbol*> dynamic_symbols;
2719 unsigned int local_dynamic_count;
2720 Versions versions(*this->script_options()->version_script_info(),
2722 this->create_dynamic_symtab(input_objects, symtab, &dynstr,
2723 &local_dynamic_count, &dynamic_symbols,
2726 // Create the .interp section to hold the name of the
2727 // interpreter, and put it in a PT_INTERP segment. Don't do it
2728 // if we saw a .interp section in an input file.
2729 if ((!parameters->options().shared()
2730 || parameters->options().dynamic_linker() != NULL)
2731 && this->interp_segment_ == NULL)
2732 this->create_interp(target);
2734 // Finish the .dynamic section to hold the dynamic data, and put
2735 // it in a PT_DYNAMIC segment.
2736 this->finish_dynamic_section(input_objects, symtab);
2738 // We should have added everything we need to the dynamic string
2740 this->dynpool_.set_string_offsets();
2742 // Create the version sections. We can't do this until the
2743 // dynamic string table is complete.
2744 this->create_version_sections(&versions, symtab, local_dynamic_count,
2745 dynamic_symbols, dynstr);
2747 // Set the size of the _DYNAMIC symbol. We can't do this until
2748 // after we call create_version_sections.
2749 this->set_dynamic_symbol_size(symtab);
2752 // Create segment headers.
2753 Output_segment_headers* segment_headers =
2754 (parameters->options().relocatable()
2756 : new Output_segment_headers(this->segment_list_));
2758 // Lay out the file header.
2759 Output_file_header* file_header = new Output_file_header(target, symtab,
2762 this->special_output_list_.push_back(file_header);
2763 if (segment_headers != NULL)
2764 this->special_output_list_.push_back(segment_headers);
2766 // Find approriate places for orphan output sections if we are using
2768 if (this->script_options_->saw_sections_clause())
2769 this->place_orphan_sections_in_script();
2771 Output_segment* load_seg;
2776 // Take a snapshot of the section layout as needed.
2777 if (target->may_relax())
2778 this->prepare_for_relaxation();
2780 // Run the relaxation loop to lay out sections.
2783 off = this->relaxation_loop_body(pass, target, symtab, &load_seg,
2784 phdr_seg, segment_headers, file_header,
2788 while (target->may_relax()
2789 && target->relax(pass, input_objects, symtab, this, task));
2791 // If there is a load segment that contains the file and program headers,
2792 // provide a symbol __ehdr_start pointing there.
2793 // A program can use this to examine itself robustly.
2794 Symbol *ehdr_start = symtab->lookup("__ehdr_start");
2795 if (ehdr_start != NULL && ehdr_start->is_predefined())
2797 if (load_seg != NULL)
2798 ehdr_start->set_output_segment(load_seg, Symbol::SEGMENT_START);
2800 ehdr_start->set_undefined();
2803 // Set the file offsets of all the non-data sections we've seen so
2804 // far which don't have to wait for the input sections. We need
2805 // this in order to finalize local symbols in non-allocated
2807 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2809 // Set the section indexes of all unallocated sections seen so far,
2810 // in case any of them are somehow referenced by a symbol.
2811 shndx = this->set_section_indexes(shndx);
2813 // Create the symbol table sections.
2814 this->create_symtab_sections(input_objects, symtab, shndx, &off);
2815 if (!parameters->doing_static_link())
2816 this->assign_local_dynsym_offsets(input_objects);
2818 // Process any symbol assignments from a linker script. This must
2819 // be called after the symbol table has been finalized.
2820 this->script_options_->finalize_symbols(symtab, this);
2822 // Create the incremental inputs sections.
2823 if (this->incremental_inputs_)
2825 this->incremental_inputs_->finalize();
2826 this->create_incremental_info_sections(symtab);
2829 // Create the .shstrtab section.
2830 Output_section* shstrtab_section = this->create_shstrtab();
2832 // Set the file offsets of the rest of the non-data sections which
2833 // don't have to wait for the input sections.
2834 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2836 // Now that all sections have been created, set the section indexes
2837 // for any sections which haven't been done yet.
2838 shndx = this->set_section_indexes(shndx);
2840 // Create the section table header.
2841 this->create_shdrs(shstrtab_section, &off);
2843 // If there are no sections which require postprocessing, we can
2844 // handle the section names now, and avoid a resize later.
2845 if (!this->any_postprocessing_sections_)
2847 off = this->set_section_offsets(off,
2848 POSTPROCESSING_SECTIONS_PASS);
2850 this->set_section_offsets(off,
2851 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
2854 file_header->set_section_info(this->section_headers_, shstrtab_section);
2856 // Now we know exactly where everything goes in the output file
2857 // (except for non-allocated sections which require postprocessing).
2858 Output_data::layout_complete();
2860 this->output_file_size_ = off;
2865 // Create a note header following the format defined in the ELF ABI.
2866 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2867 // of the section to create, DESCSZ is the size of the descriptor.
2868 // ALLOCATE is true if the section should be allocated in memory.
2869 // This returns the new note section. It sets *TRAILING_PADDING to
2870 // the number of trailing zero bytes required.
2873 Layout::create_note(const char* name, int note_type,
2874 const char* section_name, size_t descsz,
2875 bool allocate, size_t* trailing_padding)
2877 // Authorities all agree that the values in a .note field should
2878 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2879 // they differ on what the alignment is for 64-bit binaries.
2880 // The GABI says unambiguously they take 8-byte alignment:
2881 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2882 // Other documentation says alignment should always be 4 bytes:
2883 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2884 // GNU ld and GNU readelf both support the latter (at least as of
2885 // version 2.16.91), and glibc always generates the latter for
2886 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2888 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2889 const int size = parameters->target().get_size();
2891 const int size = 32;
2894 // The contents of the .note section.
2895 size_t namesz = strlen(name) + 1;
2896 size_t aligned_namesz = align_address(namesz, size / 8);
2897 size_t aligned_descsz = align_address(descsz, size / 8);
2899 size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
2901 unsigned char* buffer = new unsigned char[notehdrsz];
2902 memset(buffer, 0, notehdrsz);
2904 bool is_big_endian = parameters->target().is_big_endian();
2910 elfcpp::Swap<32, false>::writeval(buffer, namesz);
2911 elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
2912 elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
2916 elfcpp::Swap<32, true>::writeval(buffer, namesz);
2917 elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
2918 elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
2921 else if (size == 64)
2925 elfcpp::Swap<64, false>::writeval(buffer, namesz);
2926 elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
2927 elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
2931 elfcpp::Swap<64, true>::writeval(buffer, namesz);
2932 elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
2933 elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
2939 memcpy(buffer + 3 * (size / 8), name, namesz);
2941 elfcpp::Elf_Xword flags = 0;
2942 Output_section_order order = ORDER_INVALID;
2945 flags = elfcpp::SHF_ALLOC;
2946 order = ORDER_RO_NOTE;
2948 Output_section* os = this->choose_output_section(NULL, section_name,
2950 flags, false, order, false,
2955 Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
2958 os->add_output_section_data(posd);
2960 *trailing_padding = aligned_descsz - descsz;
2965 // For an executable or shared library, create a note to record the
2966 // version of gold used to create the binary.
2969 Layout::create_gold_note()
2971 if (parameters->options().relocatable()
2972 || parameters->incremental_update())
2975 std::string desc = std::string("gold ") + gold::get_version_string();
2977 size_t trailing_padding;
2978 Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
2979 ".note.gnu.gold-version", desc.size(),
2980 false, &trailing_padding);
2984 Output_section_data* posd = new Output_data_const(desc, 4);
2985 os->add_output_section_data(posd);
2987 if (trailing_padding > 0)
2989 posd = new Output_data_zero_fill(trailing_padding, 0);
2990 os->add_output_section_data(posd);
2994 // Record whether the stack should be executable. This can be set
2995 // from the command line using the -z execstack or -z noexecstack
2996 // options. Otherwise, if any input file has a .note.GNU-stack
2997 // section with the SHF_EXECINSTR flag set, the stack should be
2998 // executable. Otherwise, if at least one input file a
2999 // .note.GNU-stack section, and some input file has no .note.GNU-stack
3000 // section, we use the target default for whether the stack should be
3001 // executable. If -z stack-size was used to set a p_memsz value for
3002 // PT_GNU_STACK, we generate the segment regardless. Otherwise, we
3003 // don't generate a stack note. When generating a object file, we
3004 // create a .note.GNU-stack section with the appropriate marking.
3005 // When generating an executable or shared library, we create a
3006 // PT_GNU_STACK segment.
3009 Layout::create_stack_segment()
3011 bool is_stack_executable;
3012 if (parameters->options().is_execstack_set())
3014 is_stack_executable = parameters->options().is_stack_executable();
3015 if (!is_stack_executable
3016 && this->input_requires_executable_stack_
3017 && parameters->options().warn_execstack())
3018 gold_warning(_("one or more inputs require executable stack, "
3019 "but -z noexecstack was given"));
3021 else if (!this->input_with_gnu_stack_note_
3022 && (!parameters->options().user_set_stack_size()
3023 || parameters->options().relocatable()))
3027 if (this->input_requires_executable_stack_)
3028 is_stack_executable = true;
3029 else if (this->input_without_gnu_stack_note_)
3030 is_stack_executable =
3031 parameters->target().is_default_stack_executable();
3033 is_stack_executable = false;
3036 if (parameters->options().relocatable())
3038 const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
3039 elfcpp::Elf_Xword flags = 0;
3040 if (is_stack_executable)
3041 flags |= elfcpp::SHF_EXECINSTR;
3042 this->make_output_section(name, elfcpp::SHT_PROGBITS, flags,
3043 ORDER_INVALID, false);
3047 if (this->script_options_->saw_phdrs_clause())
3049 int flags = elfcpp::PF_R | elfcpp::PF_W;
3050 if (is_stack_executable)
3051 flags |= elfcpp::PF_X;
3052 Output_segment* seg =
3053 this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
3054 seg->set_size(parameters->options().stack_size());
3055 // BFD lets targets override this default alignment, but the only
3056 // targets that do so are ones that Gold does not support so far.
3057 seg->set_minimum_p_align(16);
3061 // If --build-id was used, set up the build ID note.
3064 Layout::create_build_id()
3066 if (!parameters->options().user_set_build_id())
3069 const char* style = parameters->options().build_id();
3070 if (strcmp(style, "none") == 0)
3073 // Set DESCSZ to the size of the note descriptor. When possible,
3074 // set DESC to the note descriptor contents.
3077 if (strcmp(style, "md5") == 0)
3079 else if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0))
3081 else if (strcmp(style, "uuid") == 0)
3084 const size_t uuidsz = 128 / 8;
3086 char buffer[uuidsz];
3087 memset(buffer, 0, uuidsz);
3089 int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
3091 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
3095 ssize_t got = ::read(descriptor, buffer, uuidsz);
3096 release_descriptor(descriptor, true);
3098 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
3099 else if (static_cast<size_t>(got) != uuidsz)
3100 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
3104 desc.assign(buffer, uuidsz);
3106 #else // __MINGW32__
3108 typedef RPC_STATUS (RPC_ENTRY *UuidCreateFn)(UUID *Uuid);
3110 HMODULE rpc_library = LoadLibrary("rpcrt4.dll");
3112 gold_error(_("--build-id=uuid failed: could not load rpcrt4.dll"));
3115 UuidCreateFn uuid_create = reinterpret_cast<UuidCreateFn>(
3116 GetProcAddress(rpc_library, "UuidCreate"));
3118 gold_error(_("--build-id=uuid failed: could not find UuidCreate"));
3119 else if (uuid_create(&uuid) != RPC_S_OK)
3120 gold_error(_("__build_id=uuid failed: call UuidCreate() failed"));
3121 FreeLibrary(rpc_library);
3123 desc.assign(reinterpret_cast<const char *>(&uuid), sizeof(UUID));
3124 descsz = sizeof(UUID);
3125 #endif // __MINGW32__
3127 else if (strncmp(style, "0x", 2) == 0)
3130 const char* p = style + 2;
3133 if (hex_p(p[0]) && hex_p(p[1]))
3135 char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
3139 else if (*p == '-' || *p == ':')
3142 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
3145 descsz = desc.size();
3148 gold_fatal(_("unrecognized --build-id argument '%s'"), style);
3151 size_t trailing_padding;
3152 Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
3153 ".note.gnu.build-id", descsz, true,
3160 // We know the value already, so we fill it in now.
3161 gold_assert(desc.size() == descsz);
3163 Output_section_data* posd = new Output_data_const(desc, 4);
3164 os->add_output_section_data(posd);
3166 if (trailing_padding != 0)
3168 posd = new Output_data_zero_fill(trailing_padding, 0);
3169 os->add_output_section_data(posd);
3174 // We need to compute a checksum after we have completed the
3176 gold_assert(trailing_padding == 0);
3177 this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
3178 os->add_output_section_data(this->build_id_note_);
3182 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3183 // field of the former should point to the latter. I'm not sure who
3184 // started this, but the GNU linker does it, and some tools depend
3188 Layout::link_stabs_sections()
3190 if (!this->have_stabstr_section_)
3193 for (Section_list::iterator p = this->section_list_.begin();
3194 p != this->section_list_.end();
3197 if ((*p)->type() != elfcpp::SHT_STRTAB)
3200 const char* name = (*p)->name();
3201 if (strncmp(name, ".stab", 5) != 0)
3204 size_t len = strlen(name);
3205 if (strcmp(name + len - 3, "str") != 0)
3208 std::string stab_name(name, len - 3);
3209 Output_section* stab_sec;
3210 stab_sec = this->find_output_section(stab_name.c_str());
3211 if (stab_sec != NULL)
3212 stab_sec->set_link_section(*p);
3216 // Create .gnu_incremental_inputs and related sections needed
3217 // for the next run of incremental linking to check what has changed.
3220 Layout::create_incremental_info_sections(Symbol_table* symtab)
3222 Incremental_inputs* incr = this->incremental_inputs_;
3224 gold_assert(incr != NULL);
3226 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3227 incr->create_data_sections(symtab);
3229 // Add the .gnu_incremental_inputs section.
3230 const char* incremental_inputs_name =
3231 this->namepool_.add(".gnu_incremental_inputs", false, NULL);
3232 Output_section* incremental_inputs_os =
3233 this->make_output_section(incremental_inputs_name,
3234 elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0,
3235 ORDER_INVALID, false);
3236 incremental_inputs_os->add_output_section_data(incr->inputs_section());
3238 // Add the .gnu_incremental_symtab section.
3239 const char* incremental_symtab_name =
3240 this->namepool_.add(".gnu_incremental_symtab", false, NULL);
3241 Output_section* incremental_symtab_os =
3242 this->make_output_section(incremental_symtab_name,
3243 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0,
3244 ORDER_INVALID, false);
3245 incremental_symtab_os->add_output_section_data(incr->symtab_section());
3246 incremental_symtab_os->set_entsize(4);
3248 // Add the .gnu_incremental_relocs section.
3249 const char* incremental_relocs_name =
3250 this->namepool_.add(".gnu_incremental_relocs", false, NULL);
3251 Output_section* incremental_relocs_os =
3252 this->make_output_section(incremental_relocs_name,
3253 elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0,
3254 ORDER_INVALID, false);
3255 incremental_relocs_os->add_output_section_data(incr->relocs_section());
3256 incremental_relocs_os->set_entsize(incr->relocs_entsize());
3258 // Add the .gnu_incremental_got_plt section.
3259 const char* incremental_got_plt_name =
3260 this->namepool_.add(".gnu_incremental_got_plt", false, NULL);
3261 Output_section* incremental_got_plt_os =
3262 this->make_output_section(incremental_got_plt_name,
3263 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0,
3264 ORDER_INVALID, false);
3265 incremental_got_plt_os->add_output_section_data(incr->got_plt_section());
3267 // Add the .gnu_incremental_strtab section.
3268 const char* incremental_strtab_name =
3269 this->namepool_.add(".gnu_incremental_strtab", false, NULL);
3270 Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name,
3271 elfcpp::SHT_STRTAB, 0,
3272 ORDER_INVALID, false);
3273 Output_data_strtab* strtab_data =
3274 new Output_data_strtab(incr->get_stringpool());
3275 incremental_strtab_os->add_output_section_data(strtab_data);
3277 incremental_inputs_os->set_after_input_sections();
3278 incremental_symtab_os->set_after_input_sections();
3279 incremental_relocs_os->set_after_input_sections();
3280 incremental_got_plt_os->set_after_input_sections();
3282 incremental_inputs_os->set_link_section(incremental_strtab_os);
3283 incremental_symtab_os->set_link_section(incremental_inputs_os);
3284 incremental_relocs_os->set_link_section(incremental_inputs_os);
3285 incremental_got_plt_os->set_link_section(incremental_inputs_os);
3288 // Return whether SEG1 should be before SEG2 in the output file. This
3289 // is based entirely on the segment type and flags. When this is
3290 // called the segment addresses have normally not yet been set.
3293 Layout::segment_precedes(const Output_segment* seg1,
3294 const Output_segment* seg2)
3296 elfcpp::Elf_Word type1 = seg1->type();
3297 elfcpp::Elf_Word type2 = seg2->type();
3299 // The single PT_PHDR segment is required to precede any loadable
3300 // segment. We simply make it always first.
3301 if (type1 == elfcpp::PT_PHDR)
3303 gold_assert(type2 != elfcpp::PT_PHDR);
3306 if (type2 == elfcpp::PT_PHDR)
3309 // The single PT_INTERP segment is required to precede any loadable
3310 // segment. We simply make it always second.
3311 if (type1 == elfcpp::PT_INTERP)
3313 gold_assert(type2 != elfcpp::PT_INTERP);
3316 if (type2 == elfcpp::PT_INTERP)
3319 // We then put PT_LOAD segments before any other segments.
3320 if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
3322 if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
3325 // We put the PT_TLS segment last except for the PT_GNU_RELRO
3326 // segment, because that is where the dynamic linker expects to find
3327 // it (this is just for efficiency; other positions would also work
3329 if (type1 == elfcpp::PT_TLS
3330 && type2 != elfcpp::PT_TLS
3331 && type2 != elfcpp::PT_GNU_RELRO)
3333 if (type2 == elfcpp::PT_TLS
3334 && type1 != elfcpp::PT_TLS
3335 && type1 != elfcpp::PT_GNU_RELRO)
3338 // We put the PT_GNU_RELRO segment last, because that is where the
3339 // dynamic linker expects to find it (as with PT_TLS, this is just
3341 if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
3343 if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
3346 const elfcpp::Elf_Word flags1 = seg1->flags();
3347 const elfcpp::Elf_Word flags2 = seg2->flags();
3349 // The order of non-PT_LOAD segments is unimportant. We simply sort
3350 // by the numeric segment type and flags values. There should not
3351 // be more than one segment with the same type and flags, except
3352 // when a linker script specifies such.
3353 if (type1 != elfcpp::PT_LOAD)
3356 return type1 < type2;
3357 gold_assert(flags1 != flags2
3358 || this->script_options_->saw_phdrs_clause());
3359 return flags1 < flags2;
3362 // If the addresses are set already, sort by load address.
3363 if (seg1->are_addresses_set())
3365 if (!seg2->are_addresses_set())
3368 unsigned int section_count1 = seg1->output_section_count();
3369 unsigned int section_count2 = seg2->output_section_count();
3370 if (section_count1 == 0 && section_count2 > 0)
3372 if (section_count1 > 0 && section_count2 == 0)
3375 uint64_t paddr1 = (seg1->are_addresses_set()
3377 : seg1->first_section_load_address());
3378 uint64_t paddr2 = (seg2->are_addresses_set()
3380 : seg2->first_section_load_address());
3382 if (paddr1 != paddr2)
3383 return paddr1 < paddr2;
3385 else if (seg2->are_addresses_set())
3388 // A segment which holds large data comes after a segment which does
3389 // not hold large data.
3390 if (seg1->is_large_data_segment())
3392 if (!seg2->is_large_data_segment())
3395 else if (seg2->is_large_data_segment())
3398 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
3399 // segments come before writable segments. Then writable segments
3400 // with data come before writable segments without data. Then
3401 // executable segments come before non-executable segments. Then
3402 // the unlikely case of a non-readable segment comes before the
3403 // normal case of a readable segment. If there are multiple
3404 // segments with the same type and flags, we require that the
3405 // address be set, and we sort by virtual address and then physical
3407 if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
3408 return (flags1 & elfcpp::PF_W) == 0;
3409 if ((flags1 & elfcpp::PF_W) != 0
3410 && seg1->has_any_data_sections() != seg2->has_any_data_sections())
3411 return seg1->has_any_data_sections();
3412 if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
3413 return (flags1 & elfcpp::PF_X) != 0;
3414 if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
3415 return (flags1 & elfcpp::PF_R) == 0;
3417 // We shouldn't get here--we shouldn't create segments which we
3418 // can't distinguish. Unless of course we are using a weird linker
3419 // script or overlapping --section-start options. We could also get
3420 // here if plugins want unique segments for subsets of sections.
3421 gold_assert(this->script_options_->saw_phdrs_clause()
3422 || parameters->options().any_section_start()
3423 || this->is_unique_segment_for_sections_specified());
3427 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3430 align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
3432 uint64_t unsigned_off = off;
3433 uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
3434 | (addr & (abi_pagesize - 1)));
3435 if (aligned_off < unsigned_off)
3436 aligned_off += abi_pagesize;
3440 // On targets where the text segment contains only executable code,
3441 // a non-executable segment is never the text segment.
3444 is_text_segment(const Target* target, const Output_segment* seg)
3446 elfcpp::Elf_Xword flags = seg->flags();
3447 if ((flags & elfcpp::PF_W) != 0)
3449 if ((flags & elfcpp::PF_X) == 0)
3450 return !target->isolate_execinstr();
3454 // Set the file offsets of all the segments, and all the sections they
3455 // contain. They have all been created. LOAD_SEG must be be laid out
3456 // first. Return the offset of the data to follow.
3459 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
3460 unsigned int* pshndx)
3462 // Sort them into the final order. We use a stable sort so that we
3463 // don't randomize the order of indistinguishable segments created
3464 // by linker scripts.
3465 std::stable_sort(this->segment_list_.begin(), this->segment_list_.end(),
3466 Layout::Compare_segments(this));
3468 // Find the PT_LOAD segments, and set their addresses and offsets
3469 // and their section's addresses and offsets.
3470 uint64_t start_addr;
3471 if (parameters->options().user_set_Ttext())
3472 start_addr = parameters->options().Ttext();
3473 else if (parameters->options().output_is_position_independent())
3476 start_addr = target->default_text_segment_address();
3478 uint64_t addr = start_addr;
3481 // If LOAD_SEG is NULL, then the file header and segment headers
3482 // will not be loadable. But they still need to be at offset 0 in
3483 // the file. Set their offsets now.
3484 if (load_seg == NULL)
3486 for (Data_list::iterator p = this->special_output_list_.begin();
3487 p != this->special_output_list_.end();
3490 off = align_address(off, (*p)->addralign());
3491 (*p)->set_address_and_file_offset(0, off);
3492 off += (*p)->data_size();
3496 unsigned int increase_relro = this->increase_relro_;
3497 if (this->script_options_->saw_sections_clause())
3500 const bool check_sections = parameters->options().check_sections();
3501 Output_segment* last_load_segment = NULL;
3503 unsigned int shndx_begin = *pshndx;
3504 unsigned int shndx_load_seg = *pshndx;
3506 for (Segment_list::iterator p = this->segment_list_.begin();
3507 p != this->segment_list_.end();
3510 if ((*p)->type() == elfcpp::PT_LOAD)
3512 if (target->isolate_execinstr())
3514 // When we hit the segment that should contain the
3515 // file headers, reset the file offset so we place
3516 // it and subsequent segments appropriately.
3517 // We'll fix up the preceding segments below.
3525 shndx_load_seg = *pshndx;
3531 // Verify that the file headers fall into the first segment.
3532 if (load_seg != NULL && load_seg != *p)
3537 bool are_addresses_set = (*p)->are_addresses_set();
3538 if (are_addresses_set)
3540 // When it comes to setting file offsets, we care about
3541 // the physical address.
3542 addr = (*p)->paddr();
3544 else if (parameters->options().user_set_Ttext()
3545 && (parameters->options().omagic()
3546 || is_text_segment(target, *p)))
3548 are_addresses_set = true;
3550 else if (parameters->options().user_set_Trodata_segment()
3551 && ((*p)->flags() & (elfcpp::PF_W | elfcpp::PF_X)) == 0)
3553 addr = parameters->options().Trodata_segment();
3554 are_addresses_set = true;
3556 else if (parameters->options().user_set_Tdata()
3557 && ((*p)->flags() & elfcpp::PF_W) != 0
3558 && (!parameters->options().user_set_Tbss()
3559 || (*p)->has_any_data_sections()))
3561 addr = parameters->options().Tdata();
3562 are_addresses_set = true;
3564 else if (parameters->options().user_set_Tbss()
3565 && ((*p)->flags() & elfcpp::PF_W) != 0
3566 && !(*p)->has_any_data_sections())
3568 addr = parameters->options().Tbss();
3569 are_addresses_set = true;
3572 uint64_t orig_addr = addr;
3573 uint64_t orig_off = off;
3575 uint64_t aligned_addr = 0;
3576 uint64_t abi_pagesize = target->abi_pagesize();
3577 uint64_t common_pagesize = target->common_pagesize();
3579 if (!parameters->options().nmagic()
3580 && !parameters->options().omagic())
3581 (*p)->set_minimum_p_align(abi_pagesize);
3583 if (!are_addresses_set)
3585 // Skip the address forward one page, maintaining the same
3586 // position within the page. This lets us store both segments
3587 // overlapping on a single page in the file, but the loader will
3588 // put them on different pages in memory. We will revisit this
3589 // decision once we know the size of the segment.
3591 uint64_t max_align = (*p)->maximum_alignment();
3592 if (max_align > abi_pagesize)
3593 addr = align_address(addr, max_align);
3594 aligned_addr = addr;
3598 // This is the segment that will contain the file
3599 // headers, so its offset will have to be exactly zero.
3600 gold_assert(orig_off == 0);
3602 // If the target wants a fixed minimum distance from the
3603 // text segment to the read-only segment, move up now.
3605 start_addr + (parameters->options().user_set_rosegment_gap()
3606 ? parameters->options().rosegment_gap()
3607 : target->rosegment_gap());
3608 if (addr < min_addr)
3611 // But this is not the first segment! To make its
3612 // address congruent with its offset, that address better
3613 // be aligned to the ABI-mandated page size.
3614 addr = align_address(addr, abi_pagesize);
3615 aligned_addr = addr;
3619 if ((addr & (abi_pagesize - 1)) != 0)
3620 addr = addr + abi_pagesize;
3622 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3626 if (!parameters->options().nmagic()
3627 && !parameters->options().omagic())
3629 // Here we are also taking care of the case when
3630 // the maximum segment alignment is larger than the page size.
3631 off = align_file_offset(off, addr,
3632 std::max(abi_pagesize,
3633 (*p)->maximum_alignment()));
3637 // This is -N or -n with a section script which prevents
3638 // us from using a load segment. We need to ensure that
3639 // the file offset is aligned to the alignment of the
3640 // segment. This is because the linker script
3641 // implicitly assumed a zero offset. If we don't align
3642 // here, then the alignment of the sections in the
3643 // linker script may not match the alignment of the
3644 // sections in the set_section_addresses call below,
3645 // causing an error about dot moving backward.
3646 off = align_address(off, (*p)->maximum_alignment());
3649 unsigned int shndx_hold = *pshndx;
3650 bool has_relro = false;
3651 uint64_t new_addr = (*p)->set_section_addresses(target, this,
3657 // Now that we know the size of this segment, we may be able
3658 // to save a page in memory, at the cost of wasting some
3659 // file space, by instead aligning to the start of a new
3660 // page. Here we use the real machine page size rather than
3661 // the ABI mandated page size. If the segment has been
3662 // aligned so that the relro data ends at a page boundary,
3663 // we do not try to realign it.
3665 if (!are_addresses_set
3667 && aligned_addr != addr
3668 && !parameters->incremental())
3670 uint64_t first_off = (common_pagesize
3672 & (common_pagesize - 1)));
3673 uint64_t last_off = new_addr & (common_pagesize - 1);
3676 && ((aligned_addr & ~ (common_pagesize - 1))
3677 != (new_addr & ~ (common_pagesize - 1)))
3678 && first_off + last_off <= common_pagesize)
3680 *pshndx = shndx_hold;
3681 addr = align_address(aligned_addr, common_pagesize);
3682 addr = align_address(addr, (*p)->maximum_alignment());
3683 if ((addr & (abi_pagesize - 1)) != 0)
3684 addr = addr + abi_pagesize;
3685 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3686 off = align_file_offset(off, addr, abi_pagesize);
3688 increase_relro = this->increase_relro_;
3689 if (this->script_options_->saw_sections_clause())
3693 new_addr = (*p)->set_section_addresses(target, this,
3703 // Implement --check-sections. We know that the segments
3704 // are sorted by LMA.
3705 if (check_sections && last_load_segment != NULL)
3707 gold_assert(last_load_segment->paddr() <= (*p)->paddr());
3708 if (last_load_segment->paddr() + last_load_segment->memsz()
3711 unsigned long long lb1 = last_load_segment->paddr();
3712 unsigned long long le1 = lb1 + last_load_segment->memsz();
3713 unsigned long long lb2 = (*p)->paddr();
3714 unsigned long long le2 = lb2 + (*p)->memsz();
3715 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3716 "[0x%llx -> 0x%llx]"),
3717 lb1, le1, lb2, le2);
3720 last_load_segment = *p;
3724 if (load_seg != NULL && target->isolate_execinstr())
3726 // Process the early segments again, setting their file offsets
3727 // so they land after the segments starting at LOAD_SEG.
3728 off = align_file_offset(off, 0, target->abi_pagesize());
3730 this->reset_relax_output();
3732 for (Segment_list::iterator p = this->segment_list_.begin();
3736 if ((*p)->type() == elfcpp::PT_LOAD)
3738 // We repeat the whole job of assigning addresses and
3739 // offsets, but we really only want to change the offsets and
3740 // must ensure that the addresses all come out the same as
3741 // they did the first time through.
3742 bool has_relro = false;
3743 const uint64_t old_addr = (*p)->vaddr();
3744 const uint64_t old_end = old_addr + (*p)->memsz();
3745 uint64_t new_addr = (*p)->set_section_addresses(target, this,
3751 gold_assert(new_addr == old_end);
3755 gold_assert(shndx_begin == shndx_load_seg);
3758 // Handle the non-PT_LOAD segments, setting their offsets from their
3759 // section's offsets.
3760 for (Segment_list::iterator p = this->segment_list_.begin();
3761 p != this->segment_list_.end();
3764 // PT_GNU_STACK was set up correctly when it was created.
3765 if ((*p)->type() != elfcpp::PT_LOAD
3766 && (*p)->type() != elfcpp::PT_GNU_STACK)
3767 (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO
3772 // Set the TLS offsets for each section in the PT_TLS segment.
3773 if (this->tls_segment_ != NULL)
3774 this->tls_segment_->set_tls_offsets();
3779 // Set the offsets of all the allocated sections when doing a
3780 // relocatable link. This does the same jobs as set_segment_offsets,
3781 // only for a relocatable link.
3784 Layout::set_relocatable_section_offsets(Output_data* file_header,
3785 unsigned int* pshndx)
3789 file_header->set_address_and_file_offset(0, 0);
3790 off += file_header->data_size();
3792 for (Section_list::iterator p = this->section_list_.begin();
3793 p != this->section_list_.end();
3796 // We skip unallocated sections here, except that group sections
3797 // have to come first.
3798 if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
3799 && (*p)->type() != elfcpp::SHT_GROUP)
3802 off = align_address(off, (*p)->addralign());
3804 // The linker script might have set the address.
3805 if (!(*p)->is_address_valid())
3806 (*p)->set_address(0);
3807 (*p)->set_file_offset(off);
3808 (*p)->finalize_data_size();
3809 if ((*p)->type() != elfcpp::SHT_NOBITS)
3810 off += (*p)->data_size();
3812 (*p)->set_out_shndx(*pshndx);
3819 // Set the file offset of all the sections not associated with a
3823 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
3825 off_t startoff = off;
3828 for (Section_list::iterator p = this->unattached_section_list_.begin();
3829 p != this->unattached_section_list_.end();
3832 // The symtab section is handled in create_symtab_sections.
3833 if (*p == this->symtab_section_)
3836 // If we've already set the data size, don't set it again.
3837 if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
3840 if (pass == BEFORE_INPUT_SECTIONS_PASS
3841 && (*p)->requires_postprocessing())
3843 (*p)->create_postprocessing_buffer();
3844 this->any_postprocessing_sections_ = true;
3847 if (pass == BEFORE_INPUT_SECTIONS_PASS
3848 && (*p)->after_input_sections())
3850 else if (pass == POSTPROCESSING_SECTIONS_PASS
3851 && (!(*p)->after_input_sections()
3852 || (*p)->type() == elfcpp::SHT_STRTAB))
3854 else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3855 && (!(*p)->after_input_sections()
3856 || (*p)->type() != elfcpp::SHT_STRTAB))
3859 if (!parameters->incremental_update())
3861 off = align_address(off, (*p)->addralign());
3862 (*p)->set_file_offset(off);
3863 (*p)->finalize_data_size();
3867 // Incremental update: allocate file space from free list.
3868 (*p)->pre_finalize_data_size();
3869 off_t current_size = (*p)->current_data_size();
3870 off = this->allocate(current_size, (*p)->addralign(), startoff);
3873 if (is_debugging_enabled(DEBUG_INCREMENTAL))
3874 this->free_list_.dump();
3875 gold_assert((*p)->output_section() != NULL);
3876 gold_fallback(_("out of patch space for section %s; "
3877 "relink with --incremental-full"),
3878 (*p)->output_section()->name());
3880 (*p)->set_file_offset(off);
3881 (*p)->finalize_data_size();
3882 if ((*p)->data_size() > current_size)
3884 gold_assert((*p)->output_section() != NULL);
3885 gold_fallback(_("%s: section changed size; "
3886 "relink with --incremental-full"),
3887 (*p)->output_section()->name());
3889 gold_debug(DEBUG_INCREMENTAL,
3890 "set_section_offsets: %08lx %08lx %s",
3891 static_cast<long>(off),
3892 static_cast<long>((*p)->data_size()),
3893 ((*p)->output_section() != NULL
3894 ? (*p)->output_section()->name() : "(special)"));
3897 off += (*p)->data_size();
3901 // At this point the name must be set.
3902 if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
3903 this->namepool_.add((*p)->name(), false, NULL);
3908 // Set the section indexes of all the sections not associated with a
3912 Layout::set_section_indexes(unsigned int shndx)
3914 for (Section_list::iterator p = this->unattached_section_list_.begin();
3915 p != this->unattached_section_list_.end();
3918 if (!(*p)->has_out_shndx())
3920 (*p)->set_out_shndx(shndx);
3927 // Set the section addresses according to the linker script. This is
3928 // only called when we see a SECTIONS clause. This returns the
3929 // program segment which should hold the file header and segment
3930 // headers, if any. It will return NULL if they should not be in a
3934 Layout::set_section_addresses_from_script(Symbol_table* symtab)
3936 Script_sections* ss = this->script_options_->script_sections();
3937 gold_assert(ss->saw_sections_clause());
3938 return this->script_options_->set_section_addresses(symtab, this);
3941 // Place the orphan sections in the linker script.
3944 Layout::place_orphan_sections_in_script()
3946 Script_sections* ss = this->script_options_->script_sections();
3947 gold_assert(ss->saw_sections_clause());
3949 // Place each orphaned output section in the script.
3950 for (Section_list::iterator p = this->section_list_.begin();
3951 p != this->section_list_.end();
3954 if (!(*p)->found_in_sections_clause())
3955 ss->place_orphan(*p);
3959 // Count the local symbols in the regular symbol table and the dynamic
3960 // symbol table, and build the respective string pools.
3963 Layout::count_local_symbols(const Task* task,
3964 const Input_objects* input_objects)
3966 // First, figure out an upper bound on the number of symbols we'll
3967 // be inserting into each pool. This helps us create the pools with
3968 // the right size, to avoid unnecessary hashtable resizing.
3969 unsigned int symbol_count = 0;
3970 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3971 p != input_objects->relobj_end();
3973 symbol_count += (*p)->local_symbol_count();
3975 // Go from "upper bound" to "estimate." We overcount for two
3976 // reasons: we double-count symbols that occur in more than one
3977 // object file, and we count symbols that are dropped from the
3978 // output. Add it all together and assume we overcount by 100%.
3981 // We assume all symbols will go into both the sympool and dynpool.
3982 this->sympool_.reserve(symbol_count);
3983 this->dynpool_.reserve(symbol_count);
3985 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3986 p != input_objects->relobj_end();
3989 Task_lock_obj<Object> tlo(task, *p);
3990 (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
3994 // Create the symbol table sections. Here we also set the final
3995 // values of the symbols. At this point all the loadable sections are
3996 // fully laid out. SHNUM is the number of sections so far.
3999 Layout::create_symtab_sections(const Input_objects* input_objects,
4000 Symbol_table* symtab,
4006 if (parameters->target().get_size() == 32)
4008 symsize = elfcpp::Elf_sizes<32>::sym_size;
4011 else if (parameters->target().get_size() == 64)
4013 symsize = elfcpp::Elf_sizes<64>::sym_size;
4019 // Compute file offsets relative to the start of the symtab section.
4022 // Save space for the dummy symbol at the start of the section. We
4023 // never bother to write this out--it will just be left as zero.
4025 unsigned int local_symbol_index = 1;
4027 // Add STT_SECTION symbols for each Output section which needs one.
4028 for (Section_list::iterator p = this->section_list_.begin();
4029 p != this->section_list_.end();
4032 if (!(*p)->needs_symtab_index())
4033 (*p)->set_symtab_index(-1U);
4036 (*p)->set_symtab_index(local_symbol_index);
4037 ++local_symbol_index;
4042 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4043 p != input_objects->relobj_end();
4046 unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
4048 off += (index - local_symbol_index) * symsize;
4049 local_symbol_index = index;
4052 unsigned int local_symcount = local_symbol_index;
4053 gold_assert(static_cast<off_t>(local_symcount * symsize) == off);
4056 size_t dyn_global_index;
4058 if (this->dynsym_section_ == NULL)
4061 dyn_global_index = 0;
4066 dyn_global_index = this->dynsym_section_->info();
4067 off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
4068 dynoff = this->dynsym_section_->offset() + locsize;
4069 dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
4070 gold_assert(static_cast<off_t>(dyncount * symsize)
4071 == this->dynsym_section_->data_size() - locsize);
4074 off_t global_off = off;
4075 off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
4076 &this->sympool_, &local_symcount);
4078 if (!parameters->options().strip_all())
4080 this->sympool_.set_string_offsets();
4082 const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
4083 Output_section* osymtab = this->make_output_section(symtab_name,
4087 this->symtab_section_ = osymtab;
4089 Output_section_data* pos = new Output_data_fixed_space(off, align,
4091 osymtab->add_output_section_data(pos);
4093 // We generate a .symtab_shndx section if we have more than
4094 // SHN_LORESERVE sections. Technically it is possible that we
4095 // don't need one, because it is possible that there are no
4096 // symbols in any of sections with indexes larger than
4097 // SHN_LORESERVE. That is probably unusual, though, and it is
4098 // easier to always create one than to compute section indexes
4099 // twice (once here, once when writing out the symbols).
4100 if (shnum >= elfcpp::SHN_LORESERVE)
4102 const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
4104 Output_section* osymtab_xindex =
4105 this->make_output_section(symtab_xindex_name,
4106 elfcpp::SHT_SYMTAB_SHNDX, 0,
4107 ORDER_INVALID, false);
4109 size_t symcount = off / symsize;
4110 this->symtab_xindex_ = new Output_symtab_xindex(symcount);
4112 osymtab_xindex->add_output_section_data(this->symtab_xindex_);
4114 osymtab_xindex->set_link_section(osymtab);
4115 osymtab_xindex->set_addralign(4);
4116 osymtab_xindex->set_entsize(4);
4118 osymtab_xindex->set_after_input_sections();
4120 // This tells the driver code to wait until the symbol table
4121 // has written out before writing out the postprocessing
4122 // sections, including the .symtab_shndx section.
4123 this->any_postprocessing_sections_ = true;
4126 const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
4127 Output_section* ostrtab = this->make_output_section(strtab_name,
4132 Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
4133 ostrtab->add_output_section_data(pstr);
4136 if (!parameters->incremental_update())
4137 symtab_off = align_address(*poff, align);
4140 symtab_off = this->allocate(off, align, *poff);
4142 gold_fallback(_("out of patch space for symbol table; "
4143 "relink with --incremental-full"));
4144 gold_debug(DEBUG_INCREMENTAL,
4145 "create_symtab_sections: %08lx %08lx .symtab",
4146 static_cast<long>(symtab_off),
4147 static_cast<long>(off));
4150 symtab->set_file_offset(symtab_off + global_off);
4151 osymtab->set_file_offset(symtab_off);
4152 osymtab->finalize_data_size();
4153 osymtab->set_link_section(ostrtab);
4154 osymtab->set_info(local_symcount);
4155 osymtab->set_entsize(symsize);
4157 if (symtab_off + off > *poff)
4158 *poff = symtab_off + off;
4162 // Create the .shstrtab section, which holds the names of the
4163 // sections. At the time this is called, we have created all the
4164 // output sections except .shstrtab itself.
4167 Layout::create_shstrtab()
4169 // FIXME: We don't need to create a .shstrtab section if we are
4170 // stripping everything.
4172 const char* name = this->namepool_.add(".shstrtab", false, NULL);
4174 Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0,
4175 ORDER_INVALID, false);
4177 if (strcmp(parameters->options().compress_debug_sections(), "none") != 0)
4179 // We can't write out this section until we've set all the
4180 // section names, and we don't set the names of compressed
4181 // output sections until relocations are complete. FIXME: With
4182 // the current names we use, this is unnecessary.
4183 os->set_after_input_sections();
4186 Output_section_data* posd = new Output_data_strtab(&this->namepool_);
4187 os->add_output_section_data(posd);
4192 // Create the section headers. SIZE is 32 or 64. OFF is the file
4196 Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
4198 Output_section_headers* oshdrs;
4199 oshdrs = new Output_section_headers(this,
4200 &this->segment_list_,
4201 &this->section_list_,
4202 &this->unattached_section_list_,
4206 if (!parameters->incremental_update())
4207 off = align_address(*poff, oshdrs->addralign());
4210 oshdrs->pre_finalize_data_size();
4211 off = this->allocate(oshdrs->data_size(), oshdrs->addralign(), *poff);
4213 gold_fallback(_("out of patch space for section header table; "
4214 "relink with --incremental-full"));
4215 gold_debug(DEBUG_INCREMENTAL,
4216 "create_shdrs: %08lx %08lx (section header table)",
4217 static_cast<long>(off),
4218 static_cast<long>(off + oshdrs->data_size()));
4220 oshdrs->set_address_and_file_offset(0, off);
4221 off += oshdrs->data_size();
4224 this->section_headers_ = oshdrs;
4227 // Count the allocated sections.
4230 Layout::allocated_output_section_count() const
4232 size_t section_count = 0;
4233 for (Segment_list::const_iterator p = this->segment_list_.begin();
4234 p != this->segment_list_.end();
4236 section_count += (*p)->output_section_count();
4237 return section_count;
4240 // Create the dynamic symbol table.
4243 Layout::create_dynamic_symtab(const Input_objects* input_objects,
4244 Symbol_table* symtab,
4245 Output_section** pdynstr,
4246 unsigned int* plocal_dynamic_count,
4247 std::vector<Symbol*>* pdynamic_symbols,
4248 Versions* pversions)
4250 // Count all the symbols in the dynamic symbol table, and set the
4251 // dynamic symbol indexes.
4253 // Skip symbol 0, which is always all zeroes.
4254 unsigned int index = 1;
4256 // Add STT_SECTION symbols for each Output section which needs one.
4257 for (Section_list::iterator p = this->section_list_.begin();
4258 p != this->section_list_.end();
4261 if (!(*p)->needs_dynsym_index())
4262 (*p)->set_dynsym_index(-1U);
4265 (*p)->set_dynsym_index(index);
4270 // Count the local symbols that need to go in the dynamic symbol table,
4271 // and set the dynamic symbol indexes.
4272 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4273 p != input_objects->relobj_end();
4276 unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
4280 unsigned int local_symcount = index;
4281 *plocal_dynamic_count = local_symcount;
4283 index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
4284 &this->dynpool_, pversions);
4288 const int size = parameters->target().get_size();
4291 symsize = elfcpp::Elf_sizes<32>::sym_size;
4294 else if (size == 64)
4296 symsize = elfcpp::Elf_sizes<64>::sym_size;
4302 // Create the dynamic symbol table section.
4304 Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
4308 ORDER_DYNAMIC_LINKER,
4309 false, false, false);
4311 // Check for NULL as a linker script may discard .dynsym.
4314 Output_section_data* odata = new Output_data_fixed_space(index * symsize,
4317 dynsym->add_output_section_data(odata);
4319 dynsym->set_info(local_symcount);
4320 dynsym->set_entsize(symsize);
4321 dynsym->set_addralign(align);
4323 this->dynsym_section_ = dynsym;
4326 Output_data_dynamic* const odyn = this->dynamic_data_;
4329 odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
4330 odyn->add_constant(elfcpp::DT_SYMENT, symsize);
4333 // If there are more than SHN_LORESERVE allocated sections, we
4334 // create a .dynsym_shndx section. It is possible that we don't
4335 // need one, because it is possible that there are no dynamic
4336 // symbols in any of the sections with indexes larger than
4337 // SHN_LORESERVE. This is probably unusual, though, and at this
4338 // time we don't know the actual section indexes so it is
4339 // inconvenient to check.
4340 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
4342 Output_section* dynsym_xindex =
4343 this->choose_output_section(NULL, ".dynsym_shndx",
4344 elfcpp::SHT_SYMTAB_SHNDX,
4346 false, ORDER_DYNAMIC_LINKER, false, false,
4349 if (dynsym_xindex != NULL)
4351 this->dynsym_xindex_ = new Output_symtab_xindex(index);
4353 dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
4355 dynsym_xindex->set_link_section(dynsym);
4356 dynsym_xindex->set_addralign(4);
4357 dynsym_xindex->set_entsize(4);
4359 dynsym_xindex->set_after_input_sections();
4361 // This tells the driver code to wait until the symbol table
4362 // has written out before writing out the postprocessing
4363 // sections, including the .dynsym_shndx section.
4364 this->any_postprocessing_sections_ = true;
4368 // Create the dynamic string table section.
4370 Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
4374 ORDER_DYNAMIC_LINKER,
4375 false, false, false);
4379 Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
4380 dynstr->add_output_section_data(strdata);
4383 dynsym->set_link_section(dynstr);
4384 if (this->dynamic_section_ != NULL)
4385 this->dynamic_section_->set_link_section(dynstr);
4389 odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
4390 odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
4394 // Create the hash tables. The Gnu-style hash table must be
4395 // built first, because it changes the order of the symbols
4396 // in the dynamic symbol table.
4398 if (strcmp(parameters->options().hash_style(), "gnu") == 0
4399 || strcmp(parameters->options().hash_style(), "both") == 0)
4401 unsigned char* phash;
4402 unsigned int hashlen;
4403 Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
4406 Output_section* hashsec =
4407 this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH,
4408 elfcpp::SHF_ALLOC, false,
4409 ORDER_DYNAMIC_LINKER, false, false,
4412 Output_section_data* hashdata = new Output_data_const_buffer(phash,
4416 if (hashsec != NULL && hashdata != NULL)
4417 hashsec->add_output_section_data(hashdata);
4419 if (hashsec != NULL)
4422 hashsec->set_link_section(dynsym);
4424 // For a 64-bit target, the entries in .gnu.hash do not have
4425 // a uniform size, so we only set the entry size for a
4427 if (parameters->target().get_size() == 32)
4428 hashsec->set_entsize(4);
4431 odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
4435 if (strcmp(parameters->options().hash_style(), "sysv") == 0
4436 || strcmp(parameters->options().hash_style(), "both") == 0)
4438 unsigned char* phash;
4439 unsigned int hashlen;
4440 Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
4443 Output_section* hashsec =
4444 this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH,
4445 elfcpp::SHF_ALLOC, false,
4446 ORDER_DYNAMIC_LINKER, false, false,
4449 Output_section_data* hashdata = new Output_data_const_buffer(phash,
4453 if (hashsec != NULL && hashdata != NULL)
4454 hashsec->add_output_section_data(hashdata);
4456 if (hashsec != NULL)
4459 hashsec->set_link_section(dynsym);
4460 hashsec->set_entsize(parameters->target().hash_entry_size() / 8);
4464 odyn->add_section_address(elfcpp::DT_HASH, hashsec);
4468 // Assign offsets to each local portion of the dynamic symbol table.
4471 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
4473 Output_section* dynsym = this->dynsym_section_;
4477 off_t off = dynsym->offset();
4479 // Skip the dummy symbol at the start of the section.
4480 off += dynsym->entsize();
4482 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4483 p != input_objects->relobj_end();
4486 unsigned int count = (*p)->set_local_dynsym_offset(off);
4487 off += count * dynsym->entsize();
4491 // Create the version sections.
4494 Layout::create_version_sections(const Versions* versions,
4495 const Symbol_table* symtab,
4496 unsigned int local_symcount,
4497 const std::vector<Symbol*>& dynamic_symbols,
4498 const Output_section* dynstr)
4500 if (!versions->any_defs() && !versions->any_needs())
4503 switch (parameters->size_and_endianness())
4505 #ifdef HAVE_TARGET_32_LITTLE
4506 case Parameters::TARGET_32_LITTLE:
4507 this->sized_create_version_sections<32, false>(versions, symtab,
4509 dynamic_symbols, dynstr);
4512 #ifdef HAVE_TARGET_32_BIG
4513 case Parameters::TARGET_32_BIG:
4514 this->sized_create_version_sections<32, true>(versions, symtab,
4516 dynamic_symbols, dynstr);
4519 #ifdef HAVE_TARGET_64_LITTLE
4520 case Parameters::TARGET_64_LITTLE:
4521 this->sized_create_version_sections<64, false>(versions, symtab,
4523 dynamic_symbols, dynstr);
4526 #ifdef HAVE_TARGET_64_BIG
4527 case Parameters::TARGET_64_BIG:
4528 this->sized_create_version_sections<64, true>(versions, symtab,
4530 dynamic_symbols, dynstr);
4538 // Create the version sections, sized version.
4540 template<int size, bool big_endian>
4542 Layout::sized_create_version_sections(
4543 const Versions* versions,
4544 const Symbol_table* symtab,
4545 unsigned int local_symcount,
4546 const std::vector<Symbol*>& dynamic_symbols,
4547 const Output_section* dynstr)
4549 Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
4550 elfcpp::SHT_GNU_versym,
4553 ORDER_DYNAMIC_LINKER,
4554 false, false, false);
4556 // Check for NULL since a linker script may discard this section.
4559 unsigned char* vbuf;
4561 versions->symbol_section_contents<size, big_endian>(symtab,
4567 Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
4570 vsec->add_output_section_data(vdata);
4571 vsec->set_entsize(2);
4572 vsec->set_link_section(this->dynsym_section_);
4575 Output_data_dynamic* const odyn = this->dynamic_data_;
4576 if (odyn != NULL && vsec != NULL)
4577 odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
4579 if (versions->any_defs())
4581 Output_section* vdsec;
4582 vdsec = this->choose_output_section(NULL, ".gnu.version_d",
4583 elfcpp::SHT_GNU_verdef,
4585 false, ORDER_DYNAMIC_LINKER, false,
4590 unsigned char* vdbuf;
4591 unsigned int vdsize;
4592 unsigned int vdentries;
4593 versions->def_section_contents<size, big_endian>(&this->dynpool_,
4597 Output_section_data* vddata =
4598 new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
4600 vdsec->add_output_section_data(vddata);
4601 vdsec->set_link_section(dynstr);
4602 vdsec->set_info(vdentries);
4606 odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
4607 odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
4612 if (versions->any_needs())
4614 Output_section* vnsec;
4615 vnsec = this->choose_output_section(NULL, ".gnu.version_r",
4616 elfcpp::SHT_GNU_verneed,
4618 false, ORDER_DYNAMIC_LINKER, false,
4623 unsigned char* vnbuf;
4624 unsigned int vnsize;
4625 unsigned int vnentries;
4626 versions->need_section_contents<size, big_endian>(&this->dynpool_,
4630 Output_section_data* vndata =
4631 new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
4633 vnsec->add_output_section_data(vndata);
4634 vnsec->set_link_section(dynstr);
4635 vnsec->set_info(vnentries);
4639 odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
4640 odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
4646 // Create the .interp section and PT_INTERP segment.
4649 Layout::create_interp(const Target* target)
4651 gold_assert(this->interp_segment_ == NULL);
4653 const char* interp = parameters->options().dynamic_linker();
4656 interp = target->dynamic_linker();
4657 gold_assert(interp != NULL);
4660 size_t len = strlen(interp) + 1;
4662 Output_section_data* odata = new Output_data_const(interp, len, 1);
4664 Output_section* osec = this->choose_output_section(NULL, ".interp",
4665 elfcpp::SHT_PROGBITS,
4667 false, ORDER_INTERP,
4668 false, false, false);
4670 osec->add_output_section_data(odata);
4673 // Add dynamic tags for the PLT and the dynamic relocs. This is
4674 // called by the target-specific code. This does nothing if not doing
4677 // USE_REL is true for REL relocs rather than RELA relocs.
4679 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
4681 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
4682 // and we also set DT_PLTREL. We use PLT_REL's output section, since
4683 // some targets have multiple reloc sections in PLT_REL.
4685 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
4686 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
4689 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
4693 Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
4694 const Output_data* plt_rel,
4695 const Output_data_reloc_generic* dyn_rel,
4696 bool add_debug, bool dynrel_includes_plt)
4698 Output_data_dynamic* odyn = this->dynamic_data_;
4702 if (plt_got != NULL && plt_got->output_section() != NULL)
4703 odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got);
4705 if (plt_rel != NULL && plt_rel->output_section() != NULL)
4707 odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section());
4708 odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section());
4709 odyn->add_constant(elfcpp::DT_PLTREL,
4710 use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA);
4713 if ((dyn_rel != NULL && dyn_rel->output_section() != NULL)
4714 || (dynrel_includes_plt
4716 && plt_rel->output_section() != NULL))
4718 bool have_dyn_rel = dyn_rel != NULL && dyn_rel->output_section() != NULL;
4719 bool have_plt_rel = plt_rel != NULL && plt_rel->output_section() != NULL;
4720 odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
4722 ? dyn_rel->output_section()
4723 : plt_rel->output_section()));
4724 elfcpp::DT size_tag = use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ;
4725 if (have_dyn_rel && have_plt_rel && dynrel_includes_plt)
4726 odyn->add_section_size(size_tag,
4727 dyn_rel->output_section(),
4728 plt_rel->output_section());
4729 else if (have_dyn_rel)
4730 odyn->add_section_size(size_tag, dyn_rel->output_section());
4732 odyn->add_section_size(size_tag, plt_rel->output_section());
4733 const int size = parameters->target().get_size();
4738 rel_tag = elfcpp::DT_RELENT;
4740 rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size;
4741 else if (size == 64)
4742 rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size;
4748 rel_tag = elfcpp::DT_RELAENT;
4750 rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size;
4751 else if (size == 64)
4752 rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size;
4756 odyn->add_constant(rel_tag, rel_size);
4758 if (parameters->options().combreloc() && have_dyn_rel)
4760 size_t c = dyn_rel->relative_reloc_count();
4762 odyn->add_constant((use_rel
4763 ? elfcpp::DT_RELCOUNT
4764 : elfcpp::DT_RELACOUNT),
4769 if (add_debug && !parameters->options().shared())
4771 // The value of the DT_DEBUG tag is filled in by the dynamic
4772 // linker at run time, and used by the debugger.
4773 odyn->add_constant(elfcpp::DT_DEBUG, 0);
4778 Layout::add_target_specific_dynamic_tag(elfcpp::DT tag, unsigned int val)
4780 Output_data_dynamic* odyn = this->dynamic_data_;
4783 odyn->add_constant(tag, val);
4786 // Finish the .dynamic section and PT_DYNAMIC segment.
4789 Layout::finish_dynamic_section(const Input_objects* input_objects,
4790 const Symbol_table* symtab)
4792 if (!this->script_options_->saw_phdrs_clause()
4793 && this->dynamic_section_ != NULL)
4795 Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
4798 oseg->add_output_section_to_nonload(this->dynamic_section_,
4799 elfcpp::PF_R | elfcpp::PF_W);
4802 Output_data_dynamic* const odyn = this->dynamic_data_;
4806 for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
4807 p != input_objects->dynobj_end();
4810 if (!(*p)->is_needed() && (*p)->as_needed())
4812 // This dynamic object was linked with --as-needed, but it
4817 odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
4820 if (parameters->options().shared())
4822 const char* soname = parameters->options().soname();
4824 odyn->add_string(elfcpp::DT_SONAME, soname);
4827 Symbol* sym = symtab->lookup(parameters->options().init());
4828 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4829 odyn->add_symbol(elfcpp::DT_INIT, sym);
4831 sym = symtab->lookup(parameters->options().fini());
4832 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4833 odyn->add_symbol(elfcpp::DT_FINI, sym);
4835 // Look for .init_array, .preinit_array and .fini_array by checking
4837 for(Layout::Section_list::const_iterator p = this->section_list_.begin();
4838 p != this->section_list_.end();
4840 switch((*p)->type())
4842 case elfcpp::SHT_FINI_ARRAY:
4843 odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p);
4844 odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p);
4846 case elfcpp::SHT_INIT_ARRAY:
4847 odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p);
4848 odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p);
4850 case elfcpp::SHT_PREINIT_ARRAY:
4851 odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p);
4852 odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p);
4858 // Add a DT_RPATH entry if needed.
4859 const General_options::Dir_list& rpath(parameters->options().rpath());
4862 std::string rpath_val;
4863 for (General_options::Dir_list::const_iterator p = rpath.begin();
4867 if (rpath_val.empty())
4868 rpath_val = p->name();
4871 // Eliminate duplicates.
4872 General_options::Dir_list::const_iterator q;
4873 for (q = rpath.begin(); q != p; ++q)
4874 if (q->name() == p->name())
4879 rpath_val += p->name();
4884 if (!parameters->options().enable_new_dtags())
4885 odyn->add_string(elfcpp::DT_RPATH, rpath_val);
4887 odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
4890 // Look for text segments that have dynamic relocations.
4891 bool have_textrel = false;
4892 if (!this->script_options_->saw_sections_clause())
4894 for (Segment_list::const_iterator p = this->segment_list_.begin();
4895 p != this->segment_list_.end();
4898 if ((*p)->type() == elfcpp::PT_LOAD
4899 && ((*p)->flags() & elfcpp::PF_W) == 0
4900 && (*p)->has_dynamic_reloc())
4902 have_textrel = true;
4909 // We don't know the section -> segment mapping, so we are
4910 // conservative and just look for readonly sections with
4911 // relocations. If those sections wind up in writable segments,
4912 // then we have created an unnecessary DT_TEXTREL entry.
4913 for (Section_list::const_iterator p = this->section_list_.begin();
4914 p != this->section_list_.end();
4917 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
4918 && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
4919 && (*p)->has_dynamic_reloc())
4921 have_textrel = true;
4927 if (parameters->options().filter() != NULL)
4928 odyn->add_string(elfcpp::DT_FILTER, parameters->options().filter());
4929 if (parameters->options().any_auxiliary())
4931 for (options::String_set::const_iterator p =
4932 parameters->options().auxiliary_begin();
4933 p != parameters->options().auxiliary_end();
4935 odyn->add_string(elfcpp::DT_AUXILIARY, *p);
4938 // Add a DT_FLAGS entry if necessary.
4939 unsigned int flags = 0;
4942 // Add a DT_TEXTREL for compatibility with older loaders.
4943 odyn->add_constant(elfcpp::DT_TEXTREL, 0);
4944 flags |= elfcpp::DF_TEXTREL;
4946 if (parameters->options().text())
4947 gold_error(_("read-only segment has dynamic relocations"));
4948 else if (parameters->options().warn_shared_textrel()
4949 && parameters->options().shared())
4950 gold_warning(_("shared library text segment is not shareable"));
4952 if (parameters->options().shared() && this->has_static_tls())
4953 flags |= elfcpp::DF_STATIC_TLS;
4954 if (parameters->options().origin())
4955 flags |= elfcpp::DF_ORIGIN;
4956 if (parameters->options().Bsymbolic()
4957 && !parameters->options().have_dynamic_list())
4959 flags |= elfcpp::DF_SYMBOLIC;
4960 // Add DT_SYMBOLIC for compatibility with older loaders.
4961 odyn->add_constant(elfcpp::DT_SYMBOLIC, 0);
4963 if (parameters->options().now())
4964 flags |= elfcpp::DF_BIND_NOW;
4966 odyn->add_constant(elfcpp::DT_FLAGS, flags);
4969 if (parameters->options().global())
4970 flags |= elfcpp::DF_1_GLOBAL;
4971 if (parameters->options().initfirst())
4972 flags |= elfcpp::DF_1_INITFIRST;
4973 if (parameters->options().interpose())
4974 flags |= elfcpp::DF_1_INTERPOSE;
4975 if (parameters->options().loadfltr())
4976 flags |= elfcpp::DF_1_LOADFLTR;
4977 if (parameters->options().nodefaultlib())
4978 flags |= elfcpp::DF_1_NODEFLIB;
4979 if (parameters->options().nodelete())
4980 flags |= elfcpp::DF_1_NODELETE;
4981 if (parameters->options().nodlopen())
4982 flags |= elfcpp::DF_1_NOOPEN;
4983 if (parameters->options().nodump())
4984 flags |= elfcpp::DF_1_NODUMP;
4985 if (!parameters->options().shared())
4986 flags &= ~(elfcpp::DF_1_INITFIRST
4987 | elfcpp::DF_1_NODELETE
4988 | elfcpp::DF_1_NOOPEN);
4989 if (parameters->options().origin())
4990 flags |= elfcpp::DF_1_ORIGIN;
4991 if (parameters->options().now())
4992 flags |= elfcpp::DF_1_NOW;
4993 if (parameters->options().Bgroup())
4994 flags |= elfcpp::DF_1_GROUP;
4996 odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
4999 // Set the size of the _DYNAMIC symbol table to be the size of the
5003 Layout::set_dynamic_symbol_size(const Symbol_table* symtab)
5005 Output_data_dynamic* const odyn = this->dynamic_data_;
5008 odyn->finalize_data_size();
5009 if (this->dynamic_symbol_ == NULL)
5011 off_t data_size = odyn->data_size();
5012 const int size = parameters->target().get_size();
5014 symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size);
5015 else if (size == 64)
5016 symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size);
5021 // The mapping of input section name prefixes to output section names.
5022 // In some cases one prefix is itself a prefix of another prefix; in
5023 // such a case the longer prefix must come first. These prefixes are
5024 // based on the GNU linker default ELF linker script.
5026 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
5027 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
5028 const Layout::Section_name_mapping Layout::section_name_mapping[] =
5030 MAPPING_INIT(".text.", ".text"),
5031 MAPPING_INIT(".rodata.", ".rodata"),
5032 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
5033 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
5034 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
5035 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
5036 MAPPING_INIT(".data.", ".data"),
5037 MAPPING_INIT(".bss.", ".bss"),
5038 MAPPING_INIT(".tdata.", ".tdata"),
5039 MAPPING_INIT(".tbss.", ".tbss"),
5040 MAPPING_INIT(".init_array.", ".init_array"),
5041 MAPPING_INIT(".fini_array.", ".fini_array"),
5042 MAPPING_INIT(".sdata.", ".sdata"),
5043 MAPPING_INIT(".sbss.", ".sbss"),
5044 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
5045 // differently depending on whether it is creating a shared library.
5046 MAPPING_INIT(".sdata2.", ".sdata"),
5047 MAPPING_INIT(".sbss2.", ".sbss"),
5048 MAPPING_INIT(".lrodata.", ".lrodata"),
5049 MAPPING_INIT(".ldata.", ".ldata"),
5050 MAPPING_INIT(".lbss.", ".lbss"),
5051 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
5052 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
5053 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
5054 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
5055 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
5056 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
5057 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
5058 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
5059 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
5060 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
5061 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
5062 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
5063 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
5064 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
5065 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
5066 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
5067 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
5068 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
5069 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
5070 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
5071 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
5074 #undef MAPPING_INIT_EXACT
5076 const int Layout::section_name_mapping_count =
5077 (sizeof(Layout::section_name_mapping)
5078 / sizeof(Layout::section_name_mapping[0]));
5080 // Choose the output section name to use given an input section name.
5081 // Set *PLEN to the length of the name. *PLEN is initialized to the
5085 Layout::output_section_name(const Relobj* relobj, const char* name,
5088 // gcc 4.3 generates the following sorts of section names when it
5089 // needs a section name specific to a function:
5095 // .data.rel.local.FN
5097 // .data.rel.ro.local.FN
5104 // The GNU linker maps all of those to the part before the .FN,
5105 // except that .data.rel.local.FN is mapped to .data, and
5106 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
5107 // beginning with .data.rel.ro.local are grouped together.
5109 // For an anonymous namespace, the string FN can contain a '.'.
5111 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
5112 // GNU linker maps to .rodata.
5114 // The .data.rel.ro sections are used with -z relro. The sections
5115 // are recognized by name. We use the same names that the GNU
5116 // linker does for these sections.
5118 // It is hard to handle this in a principled way, so we don't even
5119 // try. We use a table of mappings. If the input section name is
5120 // not found in the table, we simply use it as the output section
5123 const Section_name_mapping* psnm = section_name_mapping;
5124 for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
5126 if (psnm->fromlen > 0)
5128 if (strncmp(name, psnm->from, psnm->fromlen) == 0)
5130 *plen = psnm->tolen;
5136 if (strcmp(name, psnm->from) == 0)
5138 *plen = psnm->tolen;
5144 // As an additional complication, .ctors sections are output in
5145 // either .ctors or .init_array sections, and .dtors sections are
5146 // output in either .dtors or .fini_array sections.
5147 if (is_prefix_of(".ctors.", name) || is_prefix_of(".dtors.", name))
5149 if (parameters->options().ctors_in_init_array())
5152 return name[1] == 'c' ? ".init_array" : ".fini_array";
5157 return name[1] == 'c' ? ".ctors" : ".dtors";
5160 if (parameters->options().ctors_in_init_array()
5161 && (strcmp(name, ".ctors") == 0 || strcmp(name, ".dtors") == 0))
5163 // To make .init_array/.fini_array work with gcc we must exclude
5164 // .ctors and .dtors sections from the crtbegin and crtend
5167 || (!Layout::match_file_name(relobj, "crtbegin")
5168 && !Layout::match_file_name(relobj, "crtend")))
5171 return name[1] == 'c' ? ".init_array" : ".fini_array";
5178 // Return true if RELOBJ is an input file whose base name matches
5179 // FILE_NAME. The base name must have an extension of ".o", and must
5180 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
5181 // to match crtbegin.o as well as crtbeginS.o without getting confused
5182 // by other possibilities. Overall matching the file name this way is
5183 // a dreadful hack, but the GNU linker does it in order to better
5184 // support gcc, and we need to be compatible.
5187 Layout::match_file_name(const Relobj* relobj, const char* match)
5189 const std::string& file_name(relobj->name());
5190 const char* base_name = lbasename(file_name.c_str());
5191 size_t match_len = strlen(match);
5192 if (strncmp(base_name, match, match_len) != 0)
5194 size_t base_len = strlen(base_name);
5195 if (base_len != match_len + 2 && base_len != match_len + 3)
5197 return memcmp(base_name + base_len - 2, ".o", 2) == 0;
5200 // Check if a comdat group or .gnu.linkonce section with the given
5201 // NAME is selected for the link. If there is already a section,
5202 // *KEPT_SECTION is set to point to the existing section and the
5203 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
5204 // IS_GROUP_NAME are recorded for this NAME in the layout object,
5205 // *KEPT_SECTION is set to the internal copy and the function returns
5209 Layout::find_or_add_kept_section(const std::string& name,
5214 Kept_section** kept_section)
5216 // It's normal to see a couple of entries here, for the x86 thunk
5217 // sections. If we see more than a few, we're linking a C++
5218 // program, and we resize to get more space to minimize rehashing.
5219 if (this->signatures_.size() > 4
5220 && !this->resized_signatures_)
5222 reserve_unordered_map(&this->signatures_,
5223 this->number_of_input_files_ * 64);
5224 this->resized_signatures_ = true;
5227 Kept_section candidate;
5228 std::pair<Signatures::iterator, bool> ins =
5229 this->signatures_.insert(std::make_pair(name, candidate));
5231 if (kept_section != NULL)
5232 *kept_section = &ins.first->second;
5235 // This is the first time we've seen this signature.
5236 ins.first->second.set_object(object);
5237 ins.first->second.set_shndx(shndx);
5239 ins.first->second.set_is_comdat();
5241 ins.first->second.set_is_group_name();
5245 // We have already seen this signature.
5247 if (ins.first->second.is_group_name())
5249 // We've already seen a real section group with this signature.
5250 // If the kept group is from a plugin object, and we're in the
5251 // replacement phase, accept the new one as a replacement.
5252 if (ins.first->second.object() == NULL
5253 && parameters->options().plugins()->in_replacement_phase())
5255 ins.first->second.set_object(object);
5256 ins.first->second.set_shndx(shndx);
5261 else if (is_group_name)
5263 // This is a real section group, and we've already seen a
5264 // linkonce section with this signature. Record that we've seen
5265 // a section group, and don't include this section group.
5266 ins.first->second.set_is_group_name();
5271 // We've already seen a linkonce section and this is a linkonce
5272 // section. These don't block each other--this may be the same
5273 // symbol name with different section types.
5278 // Store the allocated sections into the section list.
5281 Layout::get_allocated_sections(Section_list* section_list) const
5283 for (Section_list::const_iterator p = this->section_list_.begin();
5284 p != this->section_list_.end();
5286 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
5287 section_list->push_back(*p);
5290 // Store the executable sections into the section list.
5293 Layout::get_executable_sections(Section_list* section_list) const
5295 for (Section_list::const_iterator p = this->section_list_.begin();
5296 p != this->section_list_.end();
5298 if (((*p)->flags() & (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR))
5299 == (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR))
5300 section_list->push_back(*p);
5303 // Create an output segment.
5306 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
5308 gold_assert(!parameters->options().relocatable());
5309 Output_segment* oseg = new Output_segment(type, flags);
5310 this->segment_list_.push_back(oseg);
5312 if (type == elfcpp::PT_TLS)
5313 this->tls_segment_ = oseg;
5314 else if (type == elfcpp::PT_GNU_RELRO)
5315 this->relro_segment_ = oseg;
5316 else if (type == elfcpp::PT_INTERP)
5317 this->interp_segment_ = oseg;
5322 // Return the file offset of the normal symbol table.
5325 Layout::symtab_section_offset() const
5327 if (this->symtab_section_ != NULL)
5328 return this->symtab_section_->offset();
5332 // Return the section index of the normal symbol table. It may have
5333 // been stripped by the -s/--strip-all option.
5336 Layout::symtab_section_shndx() const
5338 if (this->symtab_section_ != NULL)
5339 return this->symtab_section_->out_shndx();
5343 // Write out the Output_sections. Most won't have anything to write,
5344 // since most of the data will come from input sections which are
5345 // handled elsewhere. But some Output_sections do have Output_data.
5348 Layout::write_output_sections(Output_file* of) const
5350 for (Section_list::const_iterator p = this->section_list_.begin();
5351 p != this->section_list_.end();
5354 if (!(*p)->after_input_sections())
5359 // Write out data not associated with a section or the symbol table.
5362 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
5364 if (!parameters->options().strip_all())
5366 const Output_section* symtab_section = this->symtab_section_;
5367 for (Section_list::const_iterator p = this->section_list_.begin();
5368 p != this->section_list_.end();
5371 if ((*p)->needs_symtab_index())
5373 gold_assert(symtab_section != NULL);
5374 unsigned int index = (*p)->symtab_index();
5375 gold_assert(index > 0 && index != -1U);
5376 off_t off = (symtab_section->offset()
5377 + index * symtab_section->entsize());
5378 symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
5383 const Output_section* dynsym_section = this->dynsym_section_;
5384 for (Section_list::const_iterator p = this->section_list_.begin();
5385 p != this->section_list_.end();
5388 if ((*p)->needs_dynsym_index())
5390 gold_assert(dynsym_section != NULL);
5391 unsigned int index = (*p)->dynsym_index();
5392 gold_assert(index > 0 && index != -1U);
5393 off_t off = (dynsym_section->offset()
5394 + index * dynsym_section->entsize());
5395 symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
5399 // Write out the Output_data which are not in an Output_section.
5400 for (Data_list::const_iterator p = this->special_output_list_.begin();
5401 p != this->special_output_list_.end();
5405 // Write out the Output_data which are not in an Output_section
5406 // and are regenerated in each iteration of relaxation.
5407 for (Data_list::const_iterator p = this->relax_output_list_.begin();
5408 p != this->relax_output_list_.end();
5413 // Write out the Output_sections which can only be written after the
5414 // input sections are complete.
5417 Layout::write_sections_after_input_sections(Output_file* of)
5419 // Determine the final section offsets, and thus the final output
5420 // file size. Note we finalize the .shstrab last, to allow the
5421 // after_input_section sections to modify their section-names before
5423 if (this->any_postprocessing_sections_)
5425 off_t off = this->output_file_size_;
5426 off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
5428 // Now that we've finalized the names, we can finalize the shstrab.
5430 this->set_section_offsets(off,
5431 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
5433 if (off > this->output_file_size_)
5436 this->output_file_size_ = off;
5440 for (Section_list::const_iterator p = this->section_list_.begin();
5441 p != this->section_list_.end();
5444 if ((*p)->after_input_sections())
5448 this->section_headers_->write(of);
5451 // If a tree-style build ID was requested, the parallel part of that computation
5452 // is already done, and the final hash-of-hashes is computed here. For other
5453 // types of build IDs, all the work is done here.
5456 Layout::write_build_id(Output_file* of, unsigned char* array_of_hashes,
5457 size_t size_of_hashes) const
5459 if (this->build_id_note_ == NULL)
5462 unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
5463 this->build_id_note_->data_size());
5465 if (array_of_hashes == NULL)
5467 const size_t output_file_size = this->output_file_size();
5468 const unsigned char* iv = of->get_input_view(0, output_file_size);
5469 const char* style = parameters->options().build_id();
5471 // If we get here with style == "tree" then the output must be
5472 // too small for chunking, and we use SHA-1 in that case.
5473 if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0))
5474 sha1_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov);
5475 else if (strcmp(style, "md5") == 0)
5476 md5_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov);
5480 of->free_input_view(0, output_file_size, iv);
5484 // Non-overlapping substrings of the output file have been hashed.
5485 // Compute SHA-1 hash of the hashes.
5486 sha1_buffer(reinterpret_cast<const char*>(array_of_hashes),
5487 size_of_hashes, ov);
5488 delete[] array_of_hashes;
5491 of->write_output_view(this->build_id_note_->offset(),
5492 this->build_id_note_->data_size(),
5496 // Write out a binary file. This is called after the link is
5497 // complete. IN is the temporary output file we used to generate the
5498 // ELF code. We simply walk through the segments, read them from
5499 // their file offset in IN, and write them to their load address in
5500 // the output file. FIXME: with a bit more work, we could support
5501 // S-records and/or Intel hex format here.
5504 Layout::write_binary(Output_file* in) const
5506 gold_assert(parameters->options().oformat_enum()
5507 == General_options::OBJECT_FORMAT_BINARY);
5509 // Get the size of the binary file.
5510 uint64_t max_load_address = 0;
5511 for (Segment_list::const_iterator p = this->segment_list_.begin();
5512 p != this->segment_list_.end();
5515 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
5517 uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
5518 if (max_paddr > max_load_address)
5519 max_load_address = max_paddr;
5523 Output_file out(parameters->options().output_file_name());
5524 out.open(max_load_address);
5526 for (Segment_list::const_iterator p = this->segment_list_.begin();
5527 p != this->segment_list_.end();
5530 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
5532 const unsigned char* vin = in->get_input_view((*p)->offset(),
5534 unsigned char* vout = out.get_output_view((*p)->paddr(),
5536 memcpy(vout, vin, (*p)->filesz());
5537 out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
5538 in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
5545 // Print the output sections to the map file.
5548 Layout::print_to_mapfile(Mapfile* mapfile) const
5550 for (Segment_list::const_iterator p = this->segment_list_.begin();
5551 p != this->segment_list_.end();
5553 (*p)->print_sections_to_mapfile(mapfile);
5554 for (Section_list::const_iterator p = this->unattached_section_list_.begin();
5555 p != this->unattached_section_list_.end();
5557 (*p)->print_to_mapfile(mapfile);
5560 // Print statistical information to stderr. This is used for --stats.
5563 Layout::print_stats() const
5565 this->namepool_.print_stats("section name pool");
5566 this->sympool_.print_stats("output symbol name pool");
5567 this->dynpool_.print_stats("dynamic name pool");
5569 for (Section_list::const_iterator p = this->section_list_.begin();
5570 p != this->section_list_.end();
5572 (*p)->print_merge_stats();
5575 // Write_sections_task methods.
5577 // We can always run this task.
5580 Write_sections_task::is_runnable()
5585 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5589 Write_sections_task::locks(Task_locker* tl)
5591 tl->add(this, this->output_sections_blocker_);
5592 if (this->input_sections_blocker_ != NULL)
5593 tl->add(this, this->input_sections_blocker_);
5594 tl->add(this, this->final_blocker_);
5597 // Run the task--write out the data.
5600 Write_sections_task::run(Workqueue*)
5602 this->layout_->write_output_sections(this->of_);
5605 // Write_data_task methods.
5607 // We can always run this task.
5610 Write_data_task::is_runnable()
5615 // We need to unlock FINAL_BLOCKER when finished.
5618 Write_data_task::locks(Task_locker* tl)
5620 tl->add(this, this->final_blocker_);
5623 // Run the task--write out the data.
5626 Write_data_task::run(Workqueue*)
5628 this->layout_->write_data(this->symtab_, this->of_);
5631 // Write_symbols_task methods.
5633 // We can always run this task.
5636 Write_symbols_task::is_runnable()
5641 // We need to unlock FINAL_BLOCKER when finished.
5644 Write_symbols_task::locks(Task_locker* tl)
5646 tl->add(this, this->final_blocker_);
5649 // Run the task--write out the symbols.
5652 Write_symbols_task::run(Workqueue*)
5654 this->symtab_->write_globals(this->sympool_, this->dynpool_,
5655 this->layout_->symtab_xindex(),
5656 this->layout_->dynsym_xindex(), this->of_);
5659 // Write_after_input_sections_task methods.
5661 // We can only run this task after the input sections have completed.
5664 Write_after_input_sections_task::is_runnable()
5666 if (this->input_sections_blocker_->is_blocked())
5667 return this->input_sections_blocker_;
5671 // We need to unlock FINAL_BLOCKER when finished.
5674 Write_after_input_sections_task::locks(Task_locker* tl)
5676 tl->add(this, this->final_blocker_);
5682 Write_after_input_sections_task::run(Workqueue*)
5684 this->layout_->write_sections_after_input_sections(this->of_);
5687 // Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes,
5688 // or as a "tree" where each chunk of the string is hashed and then those
5689 // hashes are put into a (much smaller) string which is hashed with sha1.
5690 // We compute a checksum over the entire file because that is simplest.
5693 Build_id_task_runner::run(Workqueue* workqueue, const Task*)
5695 Task_token* post_hash_tasks_blocker = new Task_token(true);
5696 const Layout* layout = this->layout_;
5697 Output_file* of = this->of_;
5698 const size_t filesize = (layout->output_file_size() <= 0 ? 0
5699 : static_cast<size_t>(layout->output_file_size()));
5700 unsigned char* array_of_hashes = NULL;
5701 size_t size_of_hashes = 0;
5703 if (strcmp(this->options_->build_id(), "tree") == 0
5704 && this->options_->build_id_chunk_size_for_treehash() > 0
5706 && (filesize >= this->options_->build_id_min_file_size_for_treehash()))
5708 static const size_t MD5_OUTPUT_SIZE_IN_BYTES = 16;
5709 const size_t chunk_size =
5710 this->options_->build_id_chunk_size_for_treehash();
5711 const size_t num_hashes = ((filesize - 1) / chunk_size) + 1;
5712 post_hash_tasks_blocker->add_blockers(num_hashes);
5713 size_of_hashes = num_hashes * MD5_OUTPUT_SIZE_IN_BYTES;
5714 array_of_hashes = new unsigned char[size_of_hashes];
5715 unsigned char *dst = array_of_hashes;
5716 for (size_t i = 0, src_offset = 0; i < num_hashes;
5717 i++, dst += MD5_OUTPUT_SIZE_IN_BYTES, src_offset += chunk_size)
5719 size_t size = std::min(chunk_size, filesize - src_offset);
5720 workqueue->queue(new Hash_task(of,
5724 post_hash_tasks_blocker));
5728 // Queue the final task to write the build id and close the output file.
5729 workqueue->queue(new Task_function(new Close_task_runner(this->options_,
5734 post_hash_tasks_blocker,
5735 "Task_function Close_task_runner"));
5738 // Close_task_runner methods.
5740 // Finish up the build ID computation, if necessary, and write a binary file,
5741 // if necessary. Then close the output file.
5744 Close_task_runner::run(Workqueue*, const Task*)
5746 // At this point the multi-threaded part of the build ID computation,
5747 // if any, is done. See Build_id_task_runner.
5748 this->layout_->write_build_id(this->of_, this->array_of_hashes_,
5749 this->size_of_hashes_);
5751 // If we've been asked to create a binary file, we do so here.
5752 if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
5753 this->layout_->write_binary(this->of_);
5758 // Instantiate the templates we need. We could use the configure
5759 // script to restrict this to only the ones for implemented targets.
5761 #ifdef HAVE_TARGET_32_LITTLE
5764 Layout::init_fixed_output_section<32, false>(
5766 elfcpp::Shdr<32, false>& shdr);
5769 #ifdef HAVE_TARGET_32_BIG
5772 Layout::init_fixed_output_section<32, true>(
5774 elfcpp::Shdr<32, true>& shdr);
5777 #ifdef HAVE_TARGET_64_LITTLE
5780 Layout::init_fixed_output_section<64, false>(
5782 elfcpp::Shdr<64, false>& shdr);
5785 #ifdef HAVE_TARGET_64_BIG
5788 Layout::init_fixed_output_section<64, true>(
5790 elfcpp::Shdr<64, true>& shdr);
5793 #ifdef HAVE_TARGET_32_LITTLE
5796 Layout::layout<32, false>(Sized_relobj_file<32, false>* object,
5799 const elfcpp::Shdr<32, false>& shdr,
5800 unsigned int, unsigned int, off_t*);
5803 #ifdef HAVE_TARGET_32_BIG
5806 Layout::layout<32, true>(Sized_relobj_file<32, true>* object,
5809 const elfcpp::Shdr<32, true>& shdr,
5810 unsigned int, unsigned int, off_t*);
5813 #ifdef HAVE_TARGET_64_LITTLE
5816 Layout::layout<64, false>(Sized_relobj_file<64, false>* object,
5819 const elfcpp::Shdr<64, false>& shdr,
5820 unsigned int, unsigned int, off_t*);
5823 #ifdef HAVE_TARGET_64_BIG
5826 Layout::layout<64, true>(Sized_relobj_file<64, true>* object,
5829 const elfcpp::Shdr<64, true>& shdr,
5830 unsigned int, unsigned int, off_t*);
5833 #ifdef HAVE_TARGET_32_LITTLE
5836 Layout::layout_reloc<32, false>(Sized_relobj_file<32, false>* object,
5837 unsigned int reloc_shndx,
5838 const elfcpp::Shdr<32, false>& shdr,
5839 Output_section* data_section,
5840 Relocatable_relocs* rr);
5843 #ifdef HAVE_TARGET_32_BIG
5846 Layout::layout_reloc<32, true>(Sized_relobj_file<32, true>* object,
5847 unsigned int reloc_shndx,
5848 const elfcpp::Shdr<32, true>& shdr,
5849 Output_section* data_section,
5850 Relocatable_relocs* rr);
5853 #ifdef HAVE_TARGET_64_LITTLE
5856 Layout::layout_reloc<64, false>(Sized_relobj_file<64, false>* object,
5857 unsigned int reloc_shndx,
5858 const elfcpp::Shdr<64, false>& shdr,
5859 Output_section* data_section,
5860 Relocatable_relocs* rr);
5863 #ifdef HAVE_TARGET_64_BIG
5866 Layout::layout_reloc<64, true>(Sized_relobj_file<64, true>* object,
5867 unsigned int reloc_shndx,
5868 const elfcpp::Shdr<64, true>& shdr,
5869 Output_section* data_section,
5870 Relocatable_relocs* rr);
5873 #ifdef HAVE_TARGET_32_LITTLE
5876 Layout::layout_group<32, false>(Symbol_table* symtab,
5877 Sized_relobj_file<32, false>* object,
5879 const char* group_section_name,
5880 const char* signature,
5881 const elfcpp::Shdr<32, false>& shdr,
5882 elfcpp::Elf_Word flags,
5883 std::vector<unsigned int>* shndxes);
5886 #ifdef HAVE_TARGET_32_BIG
5889 Layout::layout_group<32, true>(Symbol_table* symtab,
5890 Sized_relobj_file<32, true>* object,
5892 const char* group_section_name,
5893 const char* signature,
5894 const elfcpp::Shdr<32, true>& shdr,
5895 elfcpp::Elf_Word flags,
5896 std::vector<unsigned int>* shndxes);
5899 #ifdef HAVE_TARGET_64_LITTLE
5902 Layout::layout_group<64, false>(Symbol_table* symtab,
5903 Sized_relobj_file<64, false>* object,
5905 const char* group_section_name,
5906 const char* signature,
5907 const elfcpp::Shdr<64, false>& shdr,
5908 elfcpp::Elf_Word flags,
5909 std::vector<unsigned int>* shndxes);
5912 #ifdef HAVE_TARGET_64_BIG
5915 Layout::layout_group<64, true>(Symbol_table* symtab,
5916 Sized_relobj_file<64, true>* object,
5918 const char* group_section_name,
5919 const char* signature,
5920 const elfcpp::Shdr<64, true>& shdr,
5921 elfcpp::Elf_Word flags,
5922 std::vector<unsigned int>* shndxes);
5925 #ifdef HAVE_TARGET_32_LITTLE
5928 Layout::layout_eh_frame<32, false>(Sized_relobj_file<32, false>* object,
5929 const unsigned char* symbols,
5931 const unsigned char* symbol_names,
5932 off_t symbol_names_size,
5934 const elfcpp::Shdr<32, false>& shdr,
5935 unsigned int reloc_shndx,
5936 unsigned int reloc_type,
5940 #ifdef HAVE_TARGET_32_BIG
5943 Layout::layout_eh_frame<32, true>(Sized_relobj_file<32, true>* object,
5944 const unsigned char* symbols,
5946 const unsigned char* symbol_names,
5947 off_t symbol_names_size,
5949 const elfcpp::Shdr<32, true>& shdr,
5950 unsigned int reloc_shndx,
5951 unsigned int reloc_type,
5955 #ifdef HAVE_TARGET_64_LITTLE
5958 Layout::layout_eh_frame<64, false>(Sized_relobj_file<64, false>* object,
5959 const unsigned char* symbols,
5961 const unsigned char* symbol_names,
5962 off_t symbol_names_size,
5964 const elfcpp::Shdr<64, false>& shdr,
5965 unsigned int reloc_shndx,
5966 unsigned int reloc_type,
5970 #ifdef HAVE_TARGET_64_BIG
5973 Layout::layout_eh_frame<64, true>(Sized_relobj_file<64, true>* object,
5974 const unsigned char* symbols,
5976 const unsigned char* symbol_names,
5977 off_t symbol_names_size,
5979 const elfcpp::Shdr<64, true>& shdr,
5980 unsigned int reloc_shndx,
5981 unsigned int reloc_type,
5985 #ifdef HAVE_TARGET_32_LITTLE
5988 Layout::add_to_gdb_index(bool is_type_unit,
5989 Sized_relobj<32, false>* object,
5990 const unsigned char* symbols,
5993 unsigned int reloc_shndx,
5994 unsigned int reloc_type);
5997 #ifdef HAVE_TARGET_32_BIG
6000 Layout::add_to_gdb_index(bool is_type_unit,
6001 Sized_relobj<32, true>* object,
6002 const unsigned char* symbols,
6005 unsigned int reloc_shndx,
6006 unsigned int reloc_type);
6009 #ifdef HAVE_TARGET_64_LITTLE
6012 Layout::add_to_gdb_index(bool is_type_unit,
6013 Sized_relobj<64, false>* object,
6014 const unsigned char* symbols,
6017 unsigned int reloc_shndx,
6018 unsigned int reloc_type);
6021 #ifdef HAVE_TARGET_64_BIG
6024 Layout::add_to_gdb_index(bool is_type_unit,
6025 Sized_relobj<64, true>* object,
6026 const unsigned char* symbols,
6029 unsigned int reloc_shndx,
6030 unsigned int reloc_type);
6033 } // End namespace gold.