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);
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.
941 Layout::choose_output_section(const Relobj* relobj, const char* name,
942 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
943 bool is_input_section, Output_section_order order,
944 bool is_relro, bool is_reloc)
946 // We should not see any input sections after we have attached
947 // sections to segments.
948 gold_assert(!is_input_section || !this->sections_are_attached_);
950 flags = this->get_output_section_flags(flags);
952 if (this->script_options_->saw_sections_clause() && !is_reloc)
954 // We are using a SECTIONS clause, so the output section is
955 // chosen based only on the name.
957 Script_sections* ss = this->script_options_->script_sections();
958 const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
959 Output_section** output_section_slot;
960 Script_sections::Section_type script_section_type;
961 const char* orig_name = name;
963 name = ss->output_section_name(file_name, name, &output_section_slot,
964 &script_section_type, &keep);
968 gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' "
969 "because it is not allowed by the "
970 "SECTIONS clause of the linker script"),
972 // The SECTIONS clause says to discard this input section.
976 // We can only handle script section types ST_NONE and ST_NOLOAD.
977 switch (script_section_type)
979 case Script_sections::ST_NONE:
981 case Script_sections::ST_NOLOAD:
982 flags &= elfcpp::SHF_ALLOC;
988 // If this is an orphan section--one not mentioned in the linker
989 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
990 // default processing below.
992 if (output_section_slot != NULL)
994 if (*output_section_slot != NULL)
996 (*output_section_slot)->update_flags_for_input_section(flags);
997 return *output_section_slot;
1000 // We don't put sections found in the linker script into
1001 // SECTION_NAME_MAP_. That keeps us from getting confused
1002 // if an orphan section is mapped to a section with the same
1003 // name as one in the linker script.
1005 name = this->namepool_.add(name, false, NULL);
1007 Output_section* os = this->make_output_section(name, type, flags,
1010 os->set_found_in_sections_clause();
1012 // Special handling for NOLOAD sections.
1013 if (script_section_type == Script_sections::ST_NOLOAD)
1015 os->set_is_noload();
1017 // The constructor of Output_section sets addresses of non-ALLOC
1018 // sections to 0 by default. We don't want that for NOLOAD
1019 // sections even if they have no SHF_ALLOC flag.
1020 if ((os->flags() & elfcpp::SHF_ALLOC) == 0
1021 && os->is_address_valid())
1023 gold_assert(os->address() == 0
1024 && !os->is_offset_valid()
1025 && !os->is_data_size_valid());
1026 os->reset_address_and_file_offset();
1030 *output_section_slot = os;
1035 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
1037 size_t len = strlen(name);
1038 std::string uncompressed_name;
1040 // Compressed debug sections should be mapped to the corresponding
1041 // uncompressed section.
1042 if (is_compressed_debug_section(name))
1045 corresponding_uncompressed_section_name(std::string(name, len));
1046 name = uncompressed_name.c_str();
1047 len = uncompressed_name.length();
1050 // Turn NAME from the name of the input section into the name of the
1052 if (is_input_section
1053 && !this->script_options_->saw_sections_clause()
1054 && !parameters->options().relocatable())
1056 const char *orig_name = name;
1057 name = parameters->target().output_section_name(relobj, name, &len);
1059 name = Layout::output_section_name(relobj, orig_name, &len);
1062 Stringpool::Key name_key;
1063 name = this->namepool_.add_with_length(name, len, true, &name_key);
1065 // Find or make the output section. The output section is selected
1066 // based on the section name, type, and flags.
1067 return this->get_output_section(name, name_key, type, flags, order, is_relro);
1070 // For incremental links, record the initial fixed layout of a section
1071 // from the base file, and return a pointer to the Output_section.
1073 template<int size, bool big_endian>
1075 Layout::init_fixed_output_section(const char* name,
1076 elfcpp::Shdr<size, big_endian>& shdr)
1078 unsigned int sh_type = shdr.get_sh_type();
1080 // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY,
1081 // PRE_INIT_ARRAY, and NOTE sections.
1082 // All others will be created from scratch and reallocated.
1083 if (!can_incremental_update(sh_type))
1086 // If we're generating a .gdb_index section, we need to regenerate
1088 if (parameters->options().gdb_index()
1089 && sh_type == elfcpp::SHT_PROGBITS
1090 && strcmp(name, ".gdb_index") == 0)
1093 typename elfcpp::Elf_types<size>::Elf_Addr sh_addr = shdr.get_sh_addr();
1094 typename elfcpp::Elf_types<size>::Elf_Off sh_offset = shdr.get_sh_offset();
1095 typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
1096 typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
1097 typename elfcpp::Elf_types<size>::Elf_WXword sh_addralign =
1098 shdr.get_sh_addralign();
1100 // Make the output section.
1101 Stringpool::Key name_key;
1102 name = this->namepool_.add(name, true, &name_key);
1103 Output_section* os = this->get_output_section(name, name_key, sh_type,
1104 sh_flags, ORDER_INVALID, false);
1105 os->set_fixed_layout(sh_addr, sh_offset, sh_size, sh_addralign);
1106 if (sh_type != elfcpp::SHT_NOBITS)
1107 this->free_list_.remove(sh_offset, sh_offset + sh_size);
1111 // Return the index by which an input section should be ordered. This
1112 // is used to sort some .text sections, for compatibility with GNU ld.
1115 Layout::special_ordering_of_input_section(const char* name)
1117 // The GNU linker has some special handling for some sections that
1118 // wind up in the .text section. Sections that start with these
1119 // prefixes must appear first, and must appear in the order listed
1121 static const char* const text_section_sort[] =
1130 i < sizeof(text_section_sort) / sizeof(text_section_sort[0]);
1132 if (is_prefix_of(text_section_sort[i], name))
1138 // Return the output section to use for input section SHNDX, with name
1139 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
1140 // index of a relocation section which applies to this section, or 0
1141 // if none, or -1U if more than one. RELOC_TYPE is the type of the
1142 // relocation section if there is one. Set *OFF to the offset of this
1143 // input section without the output section. Return NULL if the
1144 // section should be discarded. Set *OFF to -1 if the section
1145 // contents should not be written directly to the output file, but
1146 // will instead receive special handling.
1148 template<int size, bool big_endian>
1150 Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
1151 const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
1152 unsigned int reloc_shndx, unsigned int, off_t* off)
1156 if (!this->include_section(object, name, shdr))
1159 elfcpp::Elf_Word sh_type = shdr.get_sh_type();
1161 // In a relocatable link a grouped section must not be combined with
1162 // any other sections.
1164 if (parameters->options().relocatable()
1165 && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
1167 // Some flags in the input section should not be automatically
1168 // copied to the output section.
1169 elfcpp::Elf_Xword flags = (shdr.get_sh_flags()
1170 & ~ elfcpp::SHF_COMPRESSED);
1171 name = this->namepool_.add(name, true, NULL);
1172 os = this->make_output_section(name, sh_type, flags,
1173 ORDER_INVALID, false);
1177 // Plugins can choose to place one or more subsets of sections in
1178 // unique segments and this is done by mapping these section subsets
1179 // to unique output sections. Check if this section needs to be
1180 // remapped to a unique output section.
1181 Section_segment_map::iterator it
1182 = this->section_segment_map_.find(Const_section_id(object, shndx));
1183 if (it == this->section_segment_map_.end())
1185 os = this->choose_output_section(object, name, sh_type,
1186 shdr.get_sh_flags(), true,
1187 ORDER_INVALID, false, false);
1191 // We know the name of the output section, directly call
1192 // get_output_section here by-passing choose_output_section.
1193 elfcpp::Elf_Xword flags
1194 = this->get_output_section_flags(shdr.get_sh_flags());
1196 const char* os_name = it->second->name;
1197 Stringpool::Key name_key;
1198 os_name = this->namepool_.add(os_name, true, &name_key);
1199 os = this->get_output_section(os_name, name_key, sh_type, flags,
1200 ORDER_INVALID, false);
1201 if (!os->is_unique_segment())
1203 os->set_is_unique_segment();
1204 os->set_extra_segment_flags(it->second->flags);
1205 os->set_segment_alignment(it->second->align);
1212 // By default the GNU linker sorts input sections whose names match
1213 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The
1214 // sections are sorted by name. This is used to implement
1215 // constructor priority ordering. We are compatible. When we put
1216 // .ctor sections in .init_array and .dtor sections in .fini_array,
1217 // we must also sort plain .ctor and .dtor sections.
1218 if (!this->script_options_->saw_sections_clause()
1219 && !parameters->options().relocatable()
1220 && (is_prefix_of(".ctors.", name)
1221 || is_prefix_of(".dtors.", name)
1222 || is_prefix_of(".init_array.", name)
1223 || is_prefix_of(".fini_array.", name)
1224 || (parameters->options().ctors_in_init_array()
1225 && (strcmp(name, ".ctors") == 0
1226 || strcmp(name, ".dtors") == 0))))
1227 os->set_must_sort_attached_input_sections();
1229 // By default the GNU linker sorts some special text sections ahead
1230 // of others. We are compatible.
1231 if (parameters->options().text_reorder()
1232 && !this->script_options_->saw_sections_clause()
1233 && !this->is_section_ordering_specified()
1234 && !parameters->options().relocatable()
1235 && Layout::special_ordering_of_input_section(name) >= 0)
1236 os->set_must_sort_attached_input_sections();
1238 // If this is a .ctors or .ctors.* section being mapped to a
1239 // .init_array section, or a .dtors or .dtors.* section being mapped
1240 // to a .fini_array section, we will need to reverse the words if
1241 // there is more than one. Record this section for later. See
1242 // ctors_sections_in_init_array above.
1243 if (!this->script_options_->saw_sections_clause()
1244 && !parameters->options().relocatable()
1245 && shdr.get_sh_size() > size / 8
1246 && (((strcmp(name, ".ctors") == 0
1247 || is_prefix_of(".ctors.", name))
1248 && strcmp(os->name(), ".init_array") == 0)
1249 || ((strcmp(name, ".dtors") == 0
1250 || is_prefix_of(".dtors.", name))
1251 && strcmp(os->name(), ".fini_array") == 0)))
1252 ctors_sections_in_init_array.insert(Section_id(object, shndx));
1254 // FIXME: Handle SHF_LINK_ORDER somewhere.
1256 elfcpp::Elf_Xword orig_flags = os->flags();
1258 *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
1259 this->script_options_->saw_sections_clause());
1261 // If the flags changed, we may have to change the order.
1262 if ((orig_flags & elfcpp::SHF_ALLOC) != 0)
1264 orig_flags &= (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
1265 elfcpp::Elf_Xword new_flags =
1266 os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
1267 if (orig_flags != new_flags)
1268 os->set_order(this->default_section_order(os, false));
1271 this->have_added_input_section_ = true;
1276 // Maps section SECN to SEGMENT s.
1278 Layout::insert_section_segment_map(Const_section_id secn,
1279 Unique_segment_info *s)
1281 gold_assert(this->unique_segment_for_sections_specified_);
1282 this->section_segment_map_[secn] = s;
1285 // Handle a relocation section when doing a relocatable link.
1287 template<int size, bool big_endian>
1289 Layout::layout_reloc(Sized_relobj_file<size, big_endian>* object,
1291 const elfcpp::Shdr<size, big_endian>& shdr,
1292 Output_section* data_section,
1293 Relocatable_relocs* rr)
1295 gold_assert(parameters->options().relocatable()
1296 || parameters->options().emit_relocs());
1298 int sh_type = shdr.get_sh_type();
1301 if (sh_type == elfcpp::SHT_REL)
1303 else if (sh_type == elfcpp::SHT_RELA)
1307 name += data_section->name();
1309 // In a relocatable link relocs for a grouped section must not be
1310 // combined with other reloc sections.
1312 if (!parameters->options().relocatable()
1313 || (data_section->flags() & elfcpp::SHF_GROUP) == 0)
1314 os = this->choose_output_section(object, name.c_str(), sh_type,
1315 shdr.get_sh_flags(), false,
1316 ORDER_INVALID, false, true);
1319 const char* n = this->namepool_.add(name.c_str(), true, NULL);
1320 os = this->make_output_section(n, sh_type, shdr.get_sh_flags(),
1321 ORDER_INVALID, false);
1324 os->set_should_link_to_symtab();
1325 os->set_info_section(data_section);
1327 Output_section_data* posd;
1328 if (sh_type == elfcpp::SHT_REL)
1330 os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
1331 posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
1335 else if (sh_type == elfcpp::SHT_RELA)
1337 os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
1338 posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
1345 os->add_output_section_data(posd);
1346 rr->set_output_data(posd);
1351 // Handle a group section when doing a relocatable link.
1353 template<int size, bool big_endian>
1355 Layout::layout_group(Symbol_table* symtab,
1356 Sized_relobj_file<size, big_endian>* object,
1358 const char* group_section_name,
1359 const char* signature,
1360 const elfcpp::Shdr<size, big_endian>& shdr,
1361 elfcpp::Elf_Word flags,
1362 std::vector<unsigned int>* shndxes)
1364 gold_assert(parameters->options().relocatable());
1365 gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
1366 group_section_name = this->namepool_.add(group_section_name, true, NULL);
1367 Output_section* os = this->make_output_section(group_section_name,
1369 shdr.get_sh_flags(),
1370 ORDER_INVALID, false);
1372 // We need to find a symbol with the signature in the symbol table.
1373 // If we don't find one now, we need to look again later.
1374 Symbol* sym = symtab->lookup(signature, NULL);
1376 os->set_info_symndx(sym);
1379 // Reserve some space to minimize reallocations.
1380 if (this->group_signatures_.empty())
1381 this->group_signatures_.reserve(this->number_of_input_files_ * 16);
1383 // We will wind up using a symbol whose name is the signature.
1384 // So just put the signature in the symbol name pool to save it.
1385 signature = symtab->canonicalize_name(signature);
1386 this->group_signatures_.push_back(Group_signature(os, signature));
1389 os->set_should_link_to_symtab();
1392 section_size_type entry_count =
1393 convert_to_section_size_type(shdr.get_sh_size() / 4);
1394 Output_section_data* posd =
1395 new Output_data_group<size, big_endian>(object, entry_count, flags,
1397 os->add_output_section_data(posd);
1400 // Special GNU handling of sections name .eh_frame. They will
1401 // normally hold exception frame data as defined by the C++ ABI
1402 // (http://codesourcery.com/cxx-abi/).
1404 template<int size, bool big_endian>
1406 Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
1407 const unsigned char* symbols,
1409 const unsigned char* symbol_names,
1410 off_t symbol_names_size,
1412 const elfcpp::Shdr<size, big_endian>& shdr,
1413 unsigned int reloc_shndx, unsigned int reloc_type,
1416 gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS
1417 || shdr.get_sh_type() == elfcpp::SHT_X86_64_UNWIND);
1418 gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
1420 Output_section* os = this->make_eh_frame_section(object);
1424 gold_assert(this->eh_frame_section_ == os);
1426 elfcpp::Elf_Xword orig_flags = os->flags();
1428 Eh_frame::Eh_frame_section_disposition disp =
1429 Eh_frame::EH_UNRECOGNIZED_SECTION;
1430 if (!parameters->incremental())
1432 disp = this->eh_frame_data_->add_ehframe_input_section(object,
1442 if (disp == Eh_frame::EH_OPTIMIZABLE_SECTION)
1444 os->update_flags_for_input_section(shdr.get_sh_flags());
1446 // A writable .eh_frame section is a RELRO section.
1447 if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1448 != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1451 os->set_order(ORDER_RELRO);
1458 if (disp == Eh_frame::EH_END_MARKER_SECTION && !this->added_eh_frame_data_)
1460 // We found the end marker section, so now we can add the set of
1461 // optimized sections to the output section. We need to postpone
1462 // adding this until we've found a section we can optimize so that
1463 // the .eh_frame section in crtbeginT.o winds up at the start of
1464 // the output section.
1465 os->add_output_section_data(this->eh_frame_data_);
1466 this->added_eh_frame_data_ = true;
1469 // We couldn't handle this .eh_frame section for some reason.
1470 // Add it as a normal section.
1471 bool saw_sections_clause = this->script_options_->saw_sections_clause();
1472 *off = os->add_input_section(this, object, shndx, ".eh_frame", shdr,
1473 reloc_shndx, saw_sections_clause);
1474 this->have_added_input_section_ = true;
1476 if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1477 != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1478 os->set_order(this->default_section_order(os, false));
1484 Layout::finalize_eh_frame_section()
1486 // If we never found an end marker section, we need to add the
1487 // optimized eh sections to the output section now.
1488 if (!parameters->incremental()
1489 && this->eh_frame_section_ != NULL
1490 && !this->added_eh_frame_data_)
1492 this->eh_frame_section_->add_output_section_data(this->eh_frame_data_);
1493 this->added_eh_frame_data_ = true;
1497 // Create and return the magic .eh_frame section. Create
1498 // .eh_frame_hdr also if appropriate. OBJECT is the object with the
1499 // input .eh_frame section; it may be NULL.
1502 Layout::make_eh_frame_section(const Relobj* object)
1504 // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than
1506 Output_section* os = this->choose_output_section(object, ".eh_frame",
1507 elfcpp::SHT_PROGBITS,
1508 elfcpp::SHF_ALLOC, false,
1509 ORDER_EHFRAME, false, false);
1513 if (this->eh_frame_section_ == NULL)
1515 this->eh_frame_section_ = os;
1516 this->eh_frame_data_ = new Eh_frame();
1518 // For incremental linking, we do not optimize .eh_frame sections
1519 // or create a .eh_frame_hdr section.
1520 if (parameters->options().eh_frame_hdr() && !parameters->incremental())
1522 Output_section* hdr_os =
1523 this->choose_output_section(NULL, ".eh_frame_hdr",
1524 elfcpp::SHT_PROGBITS,
1525 elfcpp::SHF_ALLOC, false,
1526 ORDER_EHFRAME, false, false);
1530 Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
1531 this->eh_frame_data_);
1532 hdr_os->add_output_section_data(hdr_posd);
1534 hdr_os->set_after_input_sections();
1536 if (!this->script_options_->saw_phdrs_clause())
1538 Output_segment* hdr_oseg;
1539 hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
1541 hdr_oseg->add_output_section_to_nonload(hdr_os,
1545 this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
1553 // Add an exception frame for a PLT. This is called from target code.
1556 Layout::add_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data,
1557 size_t cie_length, const unsigned char* fde_data,
1560 if (parameters->incremental())
1562 // FIXME: Maybe this could work some day....
1565 Output_section* os = this->make_eh_frame_section(NULL);
1568 this->eh_frame_data_->add_ehframe_for_plt(plt, cie_data, cie_length,
1569 fde_data, fde_length);
1570 if (!this->added_eh_frame_data_)
1572 os->add_output_section_data(this->eh_frame_data_);
1573 this->added_eh_frame_data_ = true;
1577 // Scan a .debug_info or .debug_types section, and add summary
1578 // information to the .gdb_index section.
1580 template<int size, bool big_endian>
1582 Layout::add_to_gdb_index(bool is_type_unit,
1583 Sized_relobj<size, big_endian>* object,
1584 const unsigned char* symbols,
1587 unsigned int reloc_shndx,
1588 unsigned int reloc_type)
1590 if (this->gdb_index_data_ == NULL)
1592 Output_section* os = this->choose_output_section(NULL, ".gdb_index",
1593 elfcpp::SHT_PROGBITS, 0,
1594 false, ORDER_INVALID,
1599 this->gdb_index_data_ = new Gdb_index(os);
1600 os->add_output_section_data(this->gdb_index_data_);
1601 os->set_after_input_sections();
1604 this->gdb_index_data_->scan_debug_info(is_type_unit, object, symbols,
1605 symbols_size, shndx, reloc_shndx,
1609 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1610 // the output section.
1613 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
1614 elfcpp::Elf_Xword flags,
1615 Output_section_data* posd,
1616 Output_section_order order, bool is_relro)
1618 Output_section* os = this->choose_output_section(NULL, name, type, flags,
1619 false, order, is_relro,
1622 os->add_output_section_data(posd);
1626 // Map section flags to segment flags.
1629 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
1631 elfcpp::Elf_Word ret = elfcpp::PF_R;
1632 if ((flags & elfcpp::SHF_WRITE) != 0)
1633 ret |= elfcpp::PF_W;
1634 if ((flags & elfcpp::SHF_EXECINSTR) != 0)
1635 ret |= elfcpp::PF_X;
1639 // Make a new Output_section, and attach it to segments as
1640 // appropriate. ORDER is the order in which this section should
1641 // appear in the output segment. IS_RELRO is true if this is a relro
1642 // (read-only after relocations) section.
1645 Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
1646 elfcpp::Elf_Xword flags,
1647 Output_section_order order, bool is_relro)
1650 if ((flags & elfcpp::SHF_ALLOC) == 0
1651 && strcmp(parameters->options().compress_debug_sections(), "none") != 0
1652 && is_compressible_debug_section(name))
1653 os = new Output_compressed_section(¶meters->options(), name, type,
1655 else if ((flags & elfcpp::SHF_ALLOC) == 0
1656 && parameters->options().strip_debug_non_line()
1657 && strcmp(".debug_abbrev", name) == 0)
1659 os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
1661 if (this->debug_info_)
1662 this->debug_info_->set_abbreviations(this->debug_abbrev_);
1664 else if ((flags & elfcpp::SHF_ALLOC) == 0
1665 && parameters->options().strip_debug_non_line()
1666 && strcmp(".debug_info", name) == 0)
1668 os = this->debug_info_ = new Output_reduced_debug_info_section(
1670 if (this->debug_abbrev_)
1671 this->debug_info_->set_abbreviations(this->debug_abbrev_);
1675 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1676 // not have correct section types. Force them here.
1677 if (type == elfcpp::SHT_PROGBITS)
1679 if (is_prefix_of(".init_array", name))
1680 type = elfcpp::SHT_INIT_ARRAY;
1681 else if (is_prefix_of(".preinit_array", name))
1682 type = elfcpp::SHT_PREINIT_ARRAY;
1683 else if (is_prefix_of(".fini_array", name))
1684 type = elfcpp::SHT_FINI_ARRAY;
1687 // FIXME: const_cast is ugly.
1688 Target* target = const_cast<Target*>(¶meters->target());
1689 os = target->make_output_section(name, type, flags);
1692 // With -z relro, we have to recognize the special sections by name.
1693 // There is no other way.
1694 bool is_relro_local = false;
1695 if (!this->script_options_->saw_sections_clause()
1696 && parameters->options().relro()
1697 && (flags & elfcpp::SHF_ALLOC) != 0
1698 && (flags & elfcpp::SHF_WRITE) != 0)
1700 if (type == elfcpp::SHT_PROGBITS)
1702 if ((flags & elfcpp::SHF_TLS) != 0)
1704 else if (strcmp(name, ".data.rel.ro") == 0)
1706 else if (strcmp(name, ".data.rel.ro.local") == 0)
1709 is_relro_local = true;
1711 else if (strcmp(name, ".ctors") == 0
1712 || strcmp(name, ".dtors") == 0
1713 || strcmp(name, ".jcr") == 0)
1716 else if (type == elfcpp::SHT_INIT_ARRAY
1717 || type == elfcpp::SHT_FINI_ARRAY
1718 || type == elfcpp::SHT_PREINIT_ARRAY)
1725 if (order == ORDER_INVALID && (flags & elfcpp::SHF_ALLOC) != 0)
1726 order = this->default_section_order(os, is_relro_local);
1728 os->set_order(order);
1730 parameters->target().new_output_section(os);
1732 this->section_list_.push_back(os);
1734 // The GNU linker by default sorts some sections by priority, so we
1735 // do the same. We need to know that this might happen before we
1736 // attach any input sections.
1737 if (!this->script_options_->saw_sections_clause()
1738 && !parameters->options().relocatable()
1739 && (strcmp(name, ".init_array") == 0
1740 || strcmp(name, ".fini_array") == 0
1741 || (!parameters->options().ctors_in_init_array()
1742 && (strcmp(name, ".ctors") == 0
1743 || strcmp(name, ".dtors") == 0))))
1744 os->set_may_sort_attached_input_sections();
1746 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1747 // sections before other .text sections. We are compatible. We
1748 // need to know that this might happen before we attach any input
1750 if (parameters->options().text_reorder()
1751 && !this->script_options_->saw_sections_clause()
1752 && !this->is_section_ordering_specified()
1753 && !parameters->options().relocatable()
1754 && strcmp(name, ".text") == 0)
1755 os->set_may_sort_attached_input_sections();
1757 // GNU linker sorts section by name with --sort-section=name.
1758 if (strcmp(parameters->options().sort_section(), "name") == 0)
1759 os->set_must_sort_attached_input_sections();
1761 // Check for .stab*str sections, as .stab* sections need to link to
1763 if (type == elfcpp::SHT_STRTAB
1764 && !this->have_stabstr_section_
1765 && strncmp(name, ".stab", 5) == 0
1766 && strcmp(name + strlen(name) - 3, "str") == 0)
1767 this->have_stabstr_section_ = true;
1769 // During a full incremental link, we add patch space to most
1770 // PROGBITS and NOBITS sections. Flag those that may be
1771 // arbitrarily padded.
1772 if ((type == elfcpp::SHT_PROGBITS || type == elfcpp::SHT_NOBITS)
1773 && order != ORDER_INTERP
1774 && order != ORDER_INIT
1775 && order != ORDER_PLT
1776 && order != ORDER_FINI
1777 && order != ORDER_RELRO_LAST
1778 && order != ORDER_NON_RELRO_FIRST
1779 && strcmp(name, ".eh_frame") != 0
1780 && strcmp(name, ".ctors") != 0
1781 && strcmp(name, ".dtors") != 0
1782 && strcmp(name, ".jcr") != 0)
1784 os->set_is_patch_space_allowed();
1786 // Certain sections require "holes" to be filled with
1787 // specific fill patterns. These fill patterns may have
1788 // a minimum size, so we must prevent allocations from the
1789 // free list that leave a hole smaller than the minimum.
1790 if (strcmp(name, ".debug_info") == 0)
1791 os->set_free_space_fill(new Output_fill_debug_info(false));
1792 else if (strcmp(name, ".debug_types") == 0)
1793 os->set_free_space_fill(new Output_fill_debug_info(true));
1794 else if (strcmp(name, ".debug_line") == 0)
1795 os->set_free_space_fill(new Output_fill_debug_line());
1798 // If we have already attached the sections to segments, then we
1799 // need to attach this one now. This happens for sections created
1800 // directly by the linker.
1801 if (this->sections_are_attached_)
1802 this->attach_section_to_segment(¶meters->target(), os);
1807 // Return the default order in which a section should be placed in an
1808 // output segment. This function captures a lot of the ideas in
1809 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1810 // linker created section is normally set when the section is created;
1811 // this function is used for input sections.
1813 Output_section_order
1814 Layout::default_section_order(Output_section* os, bool is_relro_local)
1816 gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
1817 bool is_write = (os->flags() & elfcpp::SHF_WRITE) != 0;
1818 bool is_execinstr = (os->flags() & elfcpp::SHF_EXECINSTR) != 0;
1819 bool is_bss = false;
1824 case elfcpp::SHT_PROGBITS:
1826 case elfcpp::SHT_NOBITS:
1829 case elfcpp::SHT_RELA:
1830 case elfcpp::SHT_REL:
1832 return ORDER_DYNAMIC_RELOCS;
1834 case elfcpp::SHT_HASH:
1835 case elfcpp::SHT_DYNAMIC:
1836 case elfcpp::SHT_SHLIB:
1837 case elfcpp::SHT_DYNSYM:
1838 case elfcpp::SHT_GNU_HASH:
1839 case elfcpp::SHT_GNU_verdef:
1840 case elfcpp::SHT_GNU_verneed:
1841 case elfcpp::SHT_GNU_versym:
1843 return ORDER_DYNAMIC_LINKER;
1845 case elfcpp::SHT_NOTE:
1846 return is_write ? ORDER_RW_NOTE : ORDER_RO_NOTE;
1849 if ((os->flags() & elfcpp::SHF_TLS) != 0)
1850 return is_bss ? ORDER_TLS_BSS : ORDER_TLS_DATA;
1852 if (!is_bss && !is_write)
1856 if (strcmp(os->name(), ".init") == 0)
1858 else if (strcmp(os->name(), ".fini") == 0)
1861 return is_execinstr ? ORDER_TEXT : ORDER_READONLY;
1865 return is_relro_local ? ORDER_RELRO_LOCAL : ORDER_RELRO;
1867 if (os->is_small_section())
1868 return is_bss ? ORDER_SMALL_BSS : ORDER_SMALL_DATA;
1869 if (os->is_large_section())
1870 return is_bss ? ORDER_LARGE_BSS : ORDER_LARGE_DATA;
1872 return is_bss ? ORDER_BSS : ORDER_DATA;
1875 // Attach output sections to segments. This is called after we have
1876 // seen all the input sections.
1879 Layout::attach_sections_to_segments(const Target* target)
1881 for (Section_list::iterator p = this->section_list_.begin();
1882 p != this->section_list_.end();
1884 this->attach_section_to_segment(target, *p);
1886 this->sections_are_attached_ = true;
1889 // Attach an output section to a segment.
1892 Layout::attach_section_to_segment(const Target* target, Output_section* os)
1894 if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
1895 this->unattached_section_list_.push_back(os);
1897 this->attach_allocated_section_to_segment(target, os);
1900 // Attach an allocated output section to a segment.
1903 Layout::attach_allocated_section_to_segment(const Target* target,
1906 elfcpp::Elf_Xword flags = os->flags();
1907 gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
1909 if (parameters->options().relocatable())
1912 // If we have a SECTIONS clause, we can't handle the attachment to
1913 // segments until after we've seen all the sections.
1914 if (this->script_options_->saw_sections_clause())
1917 gold_assert(!this->script_options_->saw_phdrs_clause());
1919 // This output section goes into a PT_LOAD segment.
1921 elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
1923 // If this output section's segment has extra flags that need to be set,
1924 // coming from a linker plugin, do that.
1925 seg_flags |= os->extra_segment_flags();
1927 // Check for --section-start.
1929 bool is_address_set = parameters->options().section_start(os->name(), &addr);
1931 // In general the only thing we really care about for PT_LOAD
1932 // segments is whether or not they are writable or executable,
1933 // so that is how we search for them.
1934 // Large data sections also go into their own PT_LOAD segment.
1935 // People who need segments sorted on some other basis will
1936 // have to use a linker script.
1938 Segment_list::const_iterator p;
1939 if (!os->is_unique_segment())
1941 for (p = this->segment_list_.begin();
1942 p != this->segment_list_.end();
1945 if ((*p)->type() != elfcpp::PT_LOAD)
1947 if ((*p)->is_unique_segment())
1949 if (!parameters->options().omagic()
1950 && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
1952 if ((target->isolate_execinstr() || parameters->options().rosegment())
1953 && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
1955 // If -Tbss was specified, we need to separate the data and BSS
1957 if (parameters->options().user_set_Tbss())
1959 if ((os->type() == elfcpp::SHT_NOBITS)
1960 == (*p)->has_any_data_sections())
1963 if (os->is_large_data_section() && !(*p)->is_large_data_segment())
1968 if ((*p)->are_addresses_set())
1971 (*p)->add_initial_output_data(os);
1972 (*p)->update_flags_for_output_section(seg_flags);
1973 (*p)->set_addresses(addr, addr);
1977 (*p)->add_output_section_to_load(this, os, seg_flags);
1982 if (p == this->segment_list_.end()
1983 || os->is_unique_segment())
1985 Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
1987 if (os->is_large_data_section())
1988 oseg->set_is_large_data_segment();
1989 oseg->add_output_section_to_load(this, os, seg_flags);
1991 oseg->set_addresses(addr, addr);
1992 // Check if segment should be marked unique. For segments marked
1993 // unique by linker plugins, set the new alignment if specified.
1994 if (os->is_unique_segment())
1996 oseg->set_is_unique_segment();
1997 if (os->segment_alignment() != 0)
1998 oseg->set_minimum_p_align(os->segment_alignment());
2002 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
2004 if (os->type() == elfcpp::SHT_NOTE)
2006 // See if we already have an equivalent PT_NOTE segment.
2007 for (p = this->segment_list_.begin();
2008 p != segment_list_.end();
2011 if ((*p)->type() == elfcpp::PT_NOTE
2012 && (((*p)->flags() & elfcpp::PF_W)
2013 == (seg_flags & elfcpp::PF_W)))
2015 (*p)->add_output_section_to_nonload(os, seg_flags);
2020 if (p == this->segment_list_.end())
2022 Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
2024 oseg->add_output_section_to_nonload(os, seg_flags);
2028 // If we see a loadable SHF_TLS section, we create a PT_TLS
2029 // segment. There can only be one such segment.
2030 if ((flags & elfcpp::SHF_TLS) != 0)
2032 if (this->tls_segment_ == NULL)
2033 this->make_output_segment(elfcpp::PT_TLS, seg_flags);
2034 this->tls_segment_->add_output_section_to_nonload(os, seg_flags);
2037 // If -z relro is in effect, and we see a relro section, we create a
2038 // PT_GNU_RELRO segment. There can only be one such segment.
2039 if (os->is_relro() && parameters->options().relro())
2041 gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
2042 if (this->relro_segment_ == NULL)
2043 this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
2044 this->relro_segment_->add_output_section_to_nonload(os, seg_flags);
2047 // If we see a section named .interp, put it into a PT_INTERP
2048 // segment. This seems broken to me, but this is what GNU ld does,
2049 // and glibc expects it.
2050 if (strcmp(os->name(), ".interp") == 0
2051 && !this->script_options_->saw_phdrs_clause())
2053 if (this->interp_segment_ == NULL)
2054 this->make_output_segment(elfcpp::PT_INTERP, seg_flags);
2056 gold_warning(_("multiple '.interp' sections in input files "
2057 "may cause confusing PT_INTERP segment"));
2058 this->interp_segment_->add_output_section_to_nonload(os, seg_flags);
2062 // Make an output section for a script.
2065 Layout::make_output_section_for_script(
2067 Script_sections::Section_type section_type)
2069 name = this->namepool_.add(name, false, NULL);
2070 elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC;
2071 if (section_type == Script_sections::ST_NOLOAD)
2073 Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
2074 sh_flags, ORDER_INVALID,
2076 os->set_found_in_sections_clause();
2077 if (section_type == Script_sections::ST_NOLOAD)
2078 os->set_is_noload();
2082 // Return the number of segments we expect to see.
2085 Layout::expected_segment_count() const
2087 size_t ret = this->segment_list_.size();
2089 // If we didn't see a SECTIONS clause in a linker script, we should
2090 // already have the complete list of segments. Otherwise we ask the
2091 // SECTIONS clause how many segments it expects, and add in the ones
2092 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
2094 if (!this->script_options_->saw_sections_clause())
2098 const Script_sections* ss = this->script_options_->script_sections();
2099 return ret + ss->expected_segment_count(this);
2103 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
2104 // is whether we saw a .note.GNU-stack section in the object file.
2105 // GNU_STACK_FLAGS is the section flags. The flags give the
2106 // protection required for stack memory. We record this in an
2107 // executable as a PT_GNU_STACK segment. If an object file does not
2108 // have a .note.GNU-stack segment, we must assume that it is an old
2109 // object. On some targets that will force an executable stack.
2112 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags,
2115 if (!seen_gnu_stack)
2117 this->input_without_gnu_stack_note_ = true;
2118 if (parameters->options().warn_execstack()
2119 && parameters->target().is_default_stack_executable())
2120 gold_warning(_("%s: missing .note.GNU-stack section"
2121 " implies executable stack"),
2122 obj->name().c_str());
2126 this->input_with_gnu_stack_note_ = true;
2127 if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
2129 this->input_requires_executable_stack_ = true;
2130 if (parameters->options().warn_execstack())
2131 gold_warning(_("%s: requires executable stack"),
2132 obj->name().c_str());
2137 // Create automatic note sections.
2140 Layout::create_notes()
2142 this->create_gold_note();
2143 this->create_stack_segment();
2144 this->create_build_id();
2147 // Create the dynamic sections which are needed before we read the
2151 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
2153 if (parameters->doing_static_link())
2156 this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
2157 elfcpp::SHT_DYNAMIC,
2159 | elfcpp::SHF_WRITE),
2163 // A linker script may discard .dynamic, so check for NULL.
2164 if (this->dynamic_section_ != NULL)
2166 this->dynamic_symbol_ =
2167 symtab->define_in_output_data("_DYNAMIC", NULL,
2168 Symbol_table::PREDEFINED,
2169 this->dynamic_section_, 0, 0,
2170 elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
2171 elfcpp::STV_HIDDEN, 0, false, false);
2173 this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_);
2175 this->dynamic_section_->add_output_section_data(this->dynamic_data_);
2179 // For each output section whose name can be represented as C symbol,
2180 // define __start and __stop symbols for the section. This is a GNU
2184 Layout::define_section_symbols(Symbol_table* symtab)
2186 for (Section_list::const_iterator p = this->section_list_.begin();
2187 p != this->section_list_.end();
2190 const char* const name = (*p)->name();
2191 if (is_cident(name))
2193 const std::string name_string(name);
2194 const std::string start_name(cident_section_start_prefix
2196 const std::string stop_name(cident_section_stop_prefix
2199 symtab->define_in_output_data(start_name.c_str(),
2201 Symbol_table::PREDEFINED,
2207 elfcpp::STV_DEFAULT,
2209 false, // offset_is_from_end
2210 true); // only_if_ref
2212 symtab->define_in_output_data(stop_name.c_str(),
2214 Symbol_table::PREDEFINED,
2220 elfcpp::STV_DEFAULT,
2222 true, // offset_is_from_end
2223 true); // only_if_ref
2228 // Define symbols for group signatures.
2231 Layout::define_group_signatures(Symbol_table* symtab)
2233 for (Group_signatures::iterator p = this->group_signatures_.begin();
2234 p != this->group_signatures_.end();
2237 Symbol* sym = symtab->lookup(p->signature, NULL);
2239 p->section->set_info_symndx(sym);
2242 // Force the name of the group section to the group
2243 // signature, and use the group's section symbol as the
2244 // signature symbol.
2245 if (strcmp(p->section->name(), p->signature) != 0)
2247 const char* name = this->namepool_.add(p->signature,
2249 p->section->set_name(name);
2251 p->section->set_needs_symtab_index();
2252 p->section->set_info_section_symndx(p->section);
2256 this->group_signatures_.clear();
2259 // Find the first read-only PT_LOAD segment, creating one if
2263 Layout::find_first_load_seg(const Target* target)
2265 Output_segment* best = NULL;
2266 for (Segment_list::const_iterator p = this->segment_list_.begin();
2267 p != this->segment_list_.end();
2270 if ((*p)->type() == elfcpp::PT_LOAD
2271 && ((*p)->flags() & elfcpp::PF_R) != 0
2272 && (parameters->options().omagic()
2273 || ((*p)->flags() & elfcpp::PF_W) == 0)
2274 && (!target->isolate_execinstr()
2275 || ((*p)->flags() & elfcpp::PF_X) == 0))
2277 if (best == NULL || this->segment_precedes(*p, best))
2284 gold_assert(!this->script_options_->saw_phdrs_clause());
2286 Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
2291 // Save states of all current output segments. Store saved states
2292 // in SEGMENT_STATES.
2295 Layout::save_segments(Segment_states* segment_states)
2297 for (Segment_list::const_iterator p = this->segment_list_.begin();
2298 p != this->segment_list_.end();
2301 Output_segment* segment = *p;
2303 Output_segment* copy = new Output_segment(*segment);
2304 (*segment_states)[segment] = copy;
2308 // Restore states of output segments and delete any segment not found in
2312 Layout::restore_segments(const Segment_states* segment_states)
2314 // Go through the segment list and remove any segment added in the
2316 this->tls_segment_ = NULL;
2317 this->relro_segment_ = NULL;
2318 Segment_list::iterator list_iter = this->segment_list_.begin();
2319 while (list_iter != this->segment_list_.end())
2321 Output_segment* segment = *list_iter;
2322 Segment_states::const_iterator states_iter =
2323 segment_states->find(segment);
2324 if (states_iter != segment_states->end())
2326 const Output_segment* copy = states_iter->second;
2327 // Shallow copy to restore states.
2330 // Also fix up TLS and RELRO segment pointers as appropriate.
2331 if (segment->type() == elfcpp::PT_TLS)
2332 this->tls_segment_ = segment;
2333 else if (segment->type() == elfcpp::PT_GNU_RELRO)
2334 this->relro_segment_ = segment;
2340 list_iter = this->segment_list_.erase(list_iter);
2341 // This is a segment created during section layout. It should be
2342 // safe to remove it since we should have removed all pointers to it.
2348 // Clean up after relaxation so that sections can be laid out again.
2351 Layout::clean_up_after_relaxation()
2353 // Restore the segments to point state just prior to the relaxation loop.
2354 Script_sections* script_section = this->script_options_->script_sections();
2355 script_section->release_segments();
2356 this->restore_segments(this->segment_states_);
2358 // Reset section addresses and file offsets
2359 for (Section_list::iterator p = this->section_list_.begin();
2360 p != this->section_list_.end();
2363 (*p)->restore_states();
2365 // If an input section changes size because of relaxation,
2366 // we need to adjust the section offsets of all input sections.
2367 // after such a section.
2368 if ((*p)->section_offsets_need_adjustment())
2369 (*p)->adjust_section_offsets();
2371 (*p)->reset_address_and_file_offset();
2374 // Reset special output object address and file offsets.
2375 for (Data_list::iterator p = this->special_output_list_.begin();
2376 p != this->special_output_list_.end();
2378 (*p)->reset_address_and_file_offset();
2380 // A linker script may have created some output section data objects.
2381 // They are useless now.
2382 for (Output_section_data_list::const_iterator p =
2383 this->script_output_section_data_list_.begin();
2384 p != this->script_output_section_data_list_.end();
2387 this->script_output_section_data_list_.clear();
2389 // Special-case fill output objects are recreated each time through
2390 // the relaxation loop.
2391 this->reset_relax_output();
2395 Layout::reset_relax_output()
2397 for (Data_list::const_iterator p = this->relax_output_list_.begin();
2398 p != this->relax_output_list_.end();
2401 this->relax_output_list_.clear();
2404 // Prepare for relaxation.
2407 Layout::prepare_for_relaxation()
2409 // Create an relaxation debug check if in debugging mode.
2410 if (is_debugging_enabled(DEBUG_RELAXATION))
2411 this->relaxation_debug_check_ = new Relaxation_debug_check();
2413 // Save segment states.
2414 this->segment_states_ = new Segment_states();
2415 this->save_segments(this->segment_states_);
2417 for(Section_list::const_iterator p = this->section_list_.begin();
2418 p != this->section_list_.end();
2420 (*p)->save_states();
2422 if (is_debugging_enabled(DEBUG_RELAXATION))
2423 this->relaxation_debug_check_->check_output_data_for_reset_values(
2424 this->section_list_, this->special_output_list_,
2425 this->relax_output_list_);
2427 // Also enable recording of output section data from scripts.
2428 this->record_output_section_data_from_script_ = true;
2431 // If the user set the address of the text segment, that may not be
2432 // compatible with putting the segment headers and file headers into
2433 // that segment. For isolate_execinstr() targets, it's the rodata
2434 // segment rather than text where we might put the headers.
2436 load_seg_unusable_for_headers(const Target* target)
2438 const General_options& options = parameters->options();
2439 if (target->isolate_execinstr())
2440 return (options.user_set_Trodata_segment()
2441 && options.Trodata_segment() % target->abi_pagesize() != 0);
2443 return (options.user_set_Ttext()
2444 && options.Ttext() % target->abi_pagesize() != 0);
2447 // Relaxation loop body: If target has no relaxation, this runs only once
2448 // Otherwise, the target relaxation hook is called at the end of
2449 // each iteration. If the hook returns true, it means re-layout of
2450 // section is required.
2452 // The number of segments created by a linking script without a PHDRS
2453 // clause may be affected by section sizes and alignments. There is
2454 // a remote chance that relaxation causes different number of PT_LOAD
2455 // segments are created and sections are attached to different segments.
2456 // Therefore, we always throw away all segments created during section
2457 // layout. In order to be able to restart the section layout, we keep
2458 // a copy of the segment list right before the relaxation loop and use
2459 // that to restore the segments.
2461 // PASS is the current relaxation pass number.
2462 // SYMTAB is a symbol table.
2463 // PLOAD_SEG is the address of a pointer for the load segment.
2464 // PHDR_SEG is a pointer to the PHDR segment.
2465 // SEGMENT_HEADERS points to the output segment header.
2466 // FILE_HEADER points to the output file header.
2467 // PSHNDX is the address to store the output section index.
2470 Layout::relaxation_loop_body(
2473 Symbol_table* symtab,
2474 Output_segment** pload_seg,
2475 Output_segment* phdr_seg,
2476 Output_segment_headers* segment_headers,
2477 Output_file_header* file_header,
2478 unsigned int* pshndx)
2480 // If this is not the first iteration, we need to clean up after
2481 // relaxation so that we can lay out the sections again.
2483 this->clean_up_after_relaxation();
2485 // If there is a SECTIONS clause, put all the input sections into
2486 // the required order.
2487 Output_segment* load_seg;
2488 if (this->script_options_->saw_sections_clause())
2489 load_seg = this->set_section_addresses_from_script(symtab);
2490 else if (parameters->options().relocatable())
2493 load_seg = this->find_first_load_seg(target);
2495 if (parameters->options().oformat_enum()
2496 != General_options::OBJECT_FORMAT_ELF)
2499 if (load_seg_unusable_for_headers(target))
2505 gold_assert(phdr_seg == NULL
2507 || this->script_options_->saw_sections_clause());
2509 // If the address of the load segment we found has been set by
2510 // --section-start rather than by a script, then adjust the VMA and
2511 // LMA downward if possible to include the file and section headers.
2512 uint64_t header_gap = 0;
2513 if (load_seg != NULL
2514 && load_seg->are_addresses_set()
2515 && !this->script_options_->saw_sections_clause()
2516 && !parameters->options().relocatable())
2518 file_header->finalize_data_size();
2519 segment_headers->finalize_data_size();
2520 size_t sizeof_headers = (file_header->data_size()
2521 + segment_headers->data_size());
2522 const uint64_t abi_pagesize = target->abi_pagesize();
2523 uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers;
2524 hdr_paddr &= ~(abi_pagesize - 1);
2525 uint64_t subtract = load_seg->paddr() - hdr_paddr;
2526 if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract)
2530 load_seg->set_addresses(load_seg->vaddr() - subtract,
2531 load_seg->paddr() - subtract);
2532 header_gap = subtract - sizeof_headers;
2536 // Lay out the segment headers.
2537 if (!parameters->options().relocatable())
2539 gold_assert(segment_headers != NULL);
2540 if (header_gap != 0 && load_seg != NULL)
2542 Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1);
2543 load_seg->add_initial_output_data(z);
2545 if (load_seg != NULL)
2546 load_seg->add_initial_output_data(segment_headers);
2547 if (phdr_seg != NULL)
2548 phdr_seg->add_initial_output_data(segment_headers);
2551 // Lay out the file header.
2552 if (load_seg != NULL)
2553 load_seg->add_initial_output_data(file_header);
2555 if (this->script_options_->saw_phdrs_clause()
2556 && !parameters->options().relocatable())
2558 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2559 // clause in a linker script.
2560 Script_sections* ss = this->script_options_->script_sections();
2561 ss->put_headers_in_phdrs(file_header, segment_headers);
2564 // We set the output section indexes in set_segment_offsets and
2565 // set_section_indexes.
2568 // Set the file offsets of all the segments, and all the sections
2571 if (!parameters->options().relocatable())
2572 off = this->set_segment_offsets(target, load_seg, pshndx);
2574 off = this->set_relocatable_section_offsets(file_header, pshndx);
2576 // Verify that the dummy relaxation does not change anything.
2577 if (is_debugging_enabled(DEBUG_RELAXATION))
2580 this->relaxation_debug_check_->read_sections(this->section_list_);
2582 this->relaxation_debug_check_->verify_sections(this->section_list_);
2585 *pload_seg = load_seg;
2589 // Search the list of patterns and find the position of the given section
2590 // name in the output section. If the section name matches a glob
2591 // pattern and a non-glob name, then the non-glob position takes
2592 // precedence. Return 0 if no match is found.
2595 Layout::find_section_order_index(const std::string& section_name)
2597 Unordered_map<std::string, unsigned int>::iterator map_it;
2598 map_it = this->input_section_position_.find(section_name);
2599 if (map_it != this->input_section_position_.end())
2600 return map_it->second;
2602 // Absolute match failed. Linear search the glob patterns.
2603 std::vector<std::string>::iterator it;
2604 for (it = this->input_section_glob_.begin();
2605 it != this->input_section_glob_.end();
2608 if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0)
2610 map_it = this->input_section_position_.find(*it);
2611 gold_assert(map_it != this->input_section_position_.end());
2612 return map_it->second;
2618 // Read the sequence of input sections from the file specified with
2619 // option --section-ordering-file.
2622 Layout::read_layout_from_file()
2624 const char* filename = parameters->options().section_ordering_file();
2630 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2631 filename, strerror(errno));
2633 std::getline(in, line); // this chops off the trailing \n, if any
2634 unsigned int position = 1;
2635 this->set_section_ordering_specified();
2639 if (!line.empty() && line[line.length() - 1] == '\r') // Windows
2640 line.resize(line.length() - 1);
2641 // Ignore comments, beginning with '#'
2644 std::getline(in, line);
2647 this->input_section_position_[line] = position;
2648 // Store all glob patterns in a vector.
2649 if (is_wildcard_string(line.c_str()))
2650 this->input_section_glob_.push_back(line);
2652 std::getline(in, line);
2656 // Finalize the layout. When this is called, we have created all the
2657 // output sections and all the output segments which are based on
2658 // input sections. We have several things to do, and we have to do
2659 // them in the right order, so that we get the right results correctly
2662 // 1) Finalize the list of output segments and create the segment
2665 // 2) Finalize the dynamic symbol table and associated sections.
2667 // 3) Determine the final file offset of all the output segments.
2669 // 4) Determine the final file offset of all the SHF_ALLOC output
2672 // 5) Create the symbol table sections and the section name table
2675 // 6) Finalize the symbol table: set symbol values to their final
2676 // value and make a final determination of which symbols are going
2677 // into the output symbol table.
2679 // 7) Create the section table header.
2681 // 8) Determine the final file offset of all the output sections which
2682 // are not SHF_ALLOC, including the section table header.
2684 // 9) Finalize the ELF file header.
2686 // This function returns the size of the output file.
2689 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
2690 Target* target, const Task* task)
2692 target->finalize_sections(this, input_objects, symtab);
2694 this->count_local_symbols(task, input_objects);
2696 this->link_stabs_sections();
2698 Output_segment* phdr_seg = NULL;
2699 if (!parameters->options().relocatable() && !parameters->doing_static_link())
2701 // There was a dynamic object in the link. We need to create
2702 // some information for the dynamic linker.
2704 // Create the PT_PHDR segment which will hold the program
2706 if (!this->script_options_->saw_phdrs_clause())
2707 phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
2709 // Create the dynamic symbol table, including the hash table.
2710 Output_section* dynstr;
2711 std::vector<Symbol*> dynamic_symbols;
2712 unsigned int local_dynamic_count;
2713 Versions versions(*this->script_options()->version_script_info(),
2715 this->create_dynamic_symtab(input_objects, symtab, &dynstr,
2716 &local_dynamic_count, &dynamic_symbols,
2719 // Create the .interp section to hold the name of the
2720 // interpreter, and put it in a PT_INTERP segment. Don't do it
2721 // if we saw a .interp section in an input file.
2722 if ((!parameters->options().shared()
2723 || parameters->options().dynamic_linker() != NULL)
2724 && this->interp_segment_ == NULL)
2725 this->create_interp(target);
2727 // Finish the .dynamic section to hold the dynamic data, and put
2728 // it in a PT_DYNAMIC segment.
2729 this->finish_dynamic_section(input_objects, symtab);
2731 // We should have added everything we need to the dynamic string
2733 this->dynpool_.set_string_offsets();
2735 // Create the version sections. We can't do this until the
2736 // dynamic string table is complete.
2737 this->create_version_sections(&versions, symtab, local_dynamic_count,
2738 dynamic_symbols, dynstr);
2740 // Set the size of the _DYNAMIC symbol. We can't do this until
2741 // after we call create_version_sections.
2742 this->set_dynamic_symbol_size(symtab);
2745 // Create segment headers.
2746 Output_segment_headers* segment_headers =
2747 (parameters->options().relocatable()
2749 : new Output_segment_headers(this->segment_list_));
2751 // Lay out the file header.
2752 Output_file_header* file_header = new Output_file_header(target, symtab,
2755 this->special_output_list_.push_back(file_header);
2756 if (segment_headers != NULL)
2757 this->special_output_list_.push_back(segment_headers);
2759 // Find approriate places for orphan output sections if we are using
2761 if (this->script_options_->saw_sections_clause())
2762 this->place_orphan_sections_in_script();
2764 Output_segment* load_seg;
2769 // Take a snapshot of the section layout as needed.
2770 if (target->may_relax())
2771 this->prepare_for_relaxation();
2773 // Run the relaxation loop to lay out sections.
2776 off = this->relaxation_loop_body(pass, target, symtab, &load_seg,
2777 phdr_seg, segment_headers, file_header,
2781 while (target->may_relax()
2782 && target->relax(pass, input_objects, symtab, this, task));
2784 // If there is a load segment that contains the file and program headers,
2785 // provide a symbol __ehdr_start pointing there.
2786 // A program can use this to examine itself robustly.
2787 Symbol *ehdr_start = symtab->lookup("__ehdr_start");
2788 if (ehdr_start != NULL && ehdr_start->is_predefined())
2790 if (load_seg != NULL)
2791 ehdr_start->set_output_segment(load_seg, Symbol::SEGMENT_START);
2793 ehdr_start->set_undefined();
2796 // Set the file offsets of all the non-data sections we've seen so
2797 // far which don't have to wait for the input sections. We need
2798 // this in order to finalize local symbols in non-allocated
2800 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2802 // Set the section indexes of all unallocated sections seen so far,
2803 // in case any of them are somehow referenced by a symbol.
2804 shndx = this->set_section_indexes(shndx);
2806 // Create the symbol table sections.
2807 this->create_symtab_sections(input_objects, symtab, shndx, &off);
2808 if (!parameters->doing_static_link())
2809 this->assign_local_dynsym_offsets(input_objects);
2811 // Process any symbol assignments from a linker script. This must
2812 // be called after the symbol table has been finalized.
2813 this->script_options_->finalize_symbols(symtab, this);
2815 // Create the incremental inputs sections.
2816 if (this->incremental_inputs_)
2818 this->incremental_inputs_->finalize();
2819 this->create_incremental_info_sections(symtab);
2822 // Create the .shstrtab section.
2823 Output_section* shstrtab_section = this->create_shstrtab();
2825 // Set the file offsets of the rest of the non-data sections which
2826 // don't have to wait for the input sections.
2827 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2829 // Now that all sections have been created, set the section indexes
2830 // for any sections which haven't been done yet.
2831 shndx = this->set_section_indexes(shndx);
2833 // Create the section table header.
2834 this->create_shdrs(shstrtab_section, &off);
2836 // If there are no sections which require postprocessing, we can
2837 // handle the section names now, and avoid a resize later.
2838 if (!this->any_postprocessing_sections_)
2840 off = this->set_section_offsets(off,
2841 POSTPROCESSING_SECTIONS_PASS);
2843 this->set_section_offsets(off,
2844 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
2847 file_header->set_section_info(this->section_headers_, shstrtab_section);
2849 // Now we know exactly where everything goes in the output file
2850 // (except for non-allocated sections which require postprocessing).
2851 Output_data::layout_complete();
2853 this->output_file_size_ = off;
2858 // Create a note header following the format defined in the ELF ABI.
2859 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2860 // of the section to create, DESCSZ is the size of the descriptor.
2861 // ALLOCATE is true if the section should be allocated in memory.
2862 // This returns the new note section. It sets *TRAILING_PADDING to
2863 // the number of trailing zero bytes required.
2866 Layout::create_note(const char* name, int note_type,
2867 const char* section_name, size_t descsz,
2868 bool allocate, size_t* trailing_padding)
2870 // Authorities all agree that the values in a .note field should
2871 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2872 // they differ on what the alignment is for 64-bit binaries.
2873 // The GABI says unambiguously they take 8-byte alignment:
2874 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2875 // Other documentation says alignment should always be 4 bytes:
2876 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2877 // GNU ld and GNU readelf both support the latter (at least as of
2878 // version 2.16.91), and glibc always generates the latter for
2879 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2881 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2882 const int size = parameters->target().get_size();
2884 const int size = 32;
2887 // The contents of the .note section.
2888 size_t namesz = strlen(name) + 1;
2889 size_t aligned_namesz = align_address(namesz, size / 8);
2890 size_t aligned_descsz = align_address(descsz, size / 8);
2892 size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
2894 unsigned char* buffer = new unsigned char[notehdrsz];
2895 memset(buffer, 0, notehdrsz);
2897 bool is_big_endian = parameters->target().is_big_endian();
2903 elfcpp::Swap<32, false>::writeval(buffer, namesz);
2904 elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
2905 elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
2909 elfcpp::Swap<32, true>::writeval(buffer, namesz);
2910 elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
2911 elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
2914 else if (size == 64)
2918 elfcpp::Swap<64, false>::writeval(buffer, namesz);
2919 elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
2920 elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
2924 elfcpp::Swap<64, true>::writeval(buffer, namesz);
2925 elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
2926 elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
2932 memcpy(buffer + 3 * (size / 8), name, namesz);
2934 elfcpp::Elf_Xword flags = 0;
2935 Output_section_order order = ORDER_INVALID;
2938 flags = elfcpp::SHF_ALLOC;
2939 order = ORDER_RO_NOTE;
2941 Output_section* os = this->choose_output_section(NULL, section_name,
2943 flags, false, order, false,
2948 Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
2951 os->add_output_section_data(posd);
2953 *trailing_padding = aligned_descsz - descsz;
2958 // For an executable or shared library, create a note to record the
2959 // version of gold used to create the binary.
2962 Layout::create_gold_note()
2964 if (parameters->options().relocatable()
2965 || parameters->incremental_update())
2968 std::string desc = std::string("gold ") + gold::get_version_string();
2970 size_t trailing_padding;
2971 Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
2972 ".note.gnu.gold-version", desc.size(),
2973 false, &trailing_padding);
2977 Output_section_data* posd = new Output_data_const(desc, 4);
2978 os->add_output_section_data(posd);
2980 if (trailing_padding > 0)
2982 posd = new Output_data_zero_fill(trailing_padding, 0);
2983 os->add_output_section_data(posd);
2987 // Record whether the stack should be executable. This can be set
2988 // from the command line using the -z execstack or -z noexecstack
2989 // options. Otherwise, if any input file has a .note.GNU-stack
2990 // section with the SHF_EXECINSTR flag set, the stack should be
2991 // executable. Otherwise, if at least one input file a
2992 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2993 // section, we use the target default for whether the stack should be
2994 // executable. If -z stack-size was used to set a p_memsz value for
2995 // PT_GNU_STACK, we generate the segment regardless. Otherwise, we
2996 // don't generate a stack note. When generating a object file, we
2997 // create a .note.GNU-stack section with the appropriate marking.
2998 // When generating an executable or shared library, we create a
2999 // PT_GNU_STACK segment.
3002 Layout::create_stack_segment()
3004 bool is_stack_executable;
3005 if (parameters->options().is_execstack_set())
3007 is_stack_executable = parameters->options().is_stack_executable();
3008 if (!is_stack_executable
3009 && this->input_requires_executable_stack_
3010 && parameters->options().warn_execstack())
3011 gold_warning(_("one or more inputs require executable stack, "
3012 "but -z noexecstack was given"));
3014 else if (!this->input_with_gnu_stack_note_
3015 && (!parameters->options().user_set_stack_size()
3016 || parameters->options().relocatable()))
3020 if (this->input_requires_executable_stack_)
3021 is_stack_executable = true;
3022 else if (this->input_without_gnu_stack_note_)
3023 is_stack_executable =
3024 parameters->target().is_default_stack_executable();
3026 is_stack_executable = false;
3029 if (parameters->options().relocatable())
3031 const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
3032 elfcpp::Elf_Xword flags = 0;
3033 if (is_stack_executable)
3034 flags |= elfcpp::SHF_EXECINSTR;
3035 this->make_output_section(name, elfcpp::SHT_PROGBITS, flags,
3036 ORDER_INVALID, false);
3040 if (this->script_options_->saw_phdrs_clause())
3042 int flags = elfcpp::PF_R | elfcpp::PF_W;
3043 if (is_stack_executable)
3044 flags |= elfcpp::PF_X;
3045 Output_segment* seg =
3046 this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
3047 seg->set_size(parameters->options().stack_size());
3048 // BFD lets targets override this default alignment, but the only
3049 // targets that do so are ones that Gold does not support so far.
3050 seg->set_minimum_p_align(16);
3054 // If --build-id was used, set up the build ID note.
3057 Layout::create_build_id()
3059 if (!parameters->options().user_set_build_id())
3062 const char* style = parameters->options().build_id();
3063 if (strcmp(style, "none") == 0)
3066 // Set DESCSZ to the size of the note descriptor. When possible,
3067 // set DESC to the note descriptor contents.
3070 if (strcmp(style, "md5") == 0)
3072 else if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0))
3074 else if (strcmp(style, "uuid") == 0)
3077 const size_t uuidsz = 128 / 8;
3079 char buffer[uuidsz];
3080 memset(buffer, 0, uuidsz);
3082 int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
3084 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
3088 ssize_t got = ::read(descriptor, buffer, uuidsz);
3089 release_descriptor(descriptor, true);
3091 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
3092 else if (static_cast<size_t>(got) != uuidsz)
3093 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
3097 desc.assign(buffer, uuidsz);
3099 #else // __MINGW32__
3101 typedef RPC_STATUS (RPC_ENTRY *UuidCreateFn)(UUID *Uuid);
3103 HMODULE rpc_library = LoadLibrary("rpcrt4.dll");
3105 gold_error(_("--build-id=uuid failed: could not load rpcrt4.dll"));
3108 UuidCreateFn uuid_create = reinterpret_cast<UuidCreateFn>(
3109 GetProcAddress(rpc_library, "UuidCreate"));
3111 gold_error(_("--build-id=uuid failed: could not find UuidCreate"));
3112 else if (uuid_create(&uuid) != RPC_S_OK)
3113 gold_error(_("__build_id=uuid failed: call UuidCreate() failed"));
3114 FreeLibrary(rpc_library);
3116 desc.assign(reinterpret_cast<const char *>(&uuid), sizeof(UUID));
3117 descsz = sizeof(UUID);
3118 #endif // __MINGW32__
3120 else if (strncmp(style, "0x", 2) == 0)
3123 const char* p = style + 2;
3126 if (hex_p(p[0]) && hex_p(p[1]))
3128 char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
3132 else if (*p == '-' || *p == ':')
3135 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
3138 descsz = desc.size();
3141 gold_fatal(_("unrecognized --build-id argument '%s'"), style);
3144 size_t trailing_padding;
3145 Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
3146 ".note.gnu.build-id", descsz, true,
3153 // We know the value already, so we fill it in now.
3154 gold_assert(desc.size() == descsz);
3156 Output_section_data* posd = new Output_data_const(desc, 4);
3157 os->add_output_section_data(posd);
3159 if (trailing_padding != 0)
3161 posd = new Output_data_zero_fill(trailing_padding, 0);
3162 os->add_output_section_data(posd);
3167 // We need to compute a checksum after we have completed the
3169 gold_assert(trailing_padding == 0);
3170 this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
3171 os->add_output_section_data(this->build_id_note_);
3175 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3176 // field of the former should point to the latter. I'm not sure who
3177 // started this, but the GNU linker does it, and some tools depend
3181 Layout::link_stabs_sections()
3183 if (!this->have_stabstr_section_)
3186 for (Section_list::iterator p = this->section_list_.begin();
3187 p != this->section_list_.end();
3190 if ((*p)->type() != elfcpp::SHT_STRTAB)
3193 const char* name = (*p)->name();
3194 if (strncmp(name, ".stab", 5) != 0)
3197 size_t len = strlen(name);
3198 if (strcmp(name + len - 3, "str") != 0)
3201 std::string stab_name(name, len - 3);
3202 Output_section* stab_sec;
3203 stab_sec = this->find_output_section(stab_name.c_str());
3204 if (stab_sec != NULL)
3205 stab_sec->set_link_section(*p);
3209 // Create .gnu_incremental_inputs and related sections needed
3210 // for the next run of incremental linking to check what has changed.
3213 Layout::create_incremental_info_sections(Symbol_table* symtab)
3215 Incremental_inputs* incr = this->incremental_inputs_;
3217 gold_assert(incr != NULL);
3219 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3220 incr->create_data_sections(symtab);
3222 // Add the .gnu_incremental_inputs section.
3223 const char* incremental_inputs_name =
3224 this->namepool_.add(".gnu_incremental_inputs", false, NULL);
3225 Output_section* incremental_inputs_os =
3226 this->make_output_section(incremental_inputs_name,
3227 elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0,
3228 ORDER_INVALID, false);
3229 incremental_inputs_os->add_output_section_data(incr->inputs_section());
3231 // Add the .gnu_incremental_symtab section.
3232 const char* incremental_symtab_name =
3233 this->namepool_.add(".gnu_incremental_symtab", false, NULL);
3234 Output_section* incremental_symtab_os =
3235 this->make_output_section(incremental_symtab_name,
3236 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0,
3237 ORDER_INVALID, false);
3238 incremental_symtab_os->add_output_section_data(incr->symtab_section());
3239 incremental_symtab_os->set_entsize(4);
3241 // Add the .gnu_incremental_relocs section.
3242 const char* incremental_relocs_name =
3243 this->namepool_.add(".gnu_incremental_relocs", false, NULL);
3244 Output_section* incremental_relocs_os =
3245 this->make_output_section(incremental_relocs_name,
3246 elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0,
3247 ORDER_INVALID, false);
3248 incremental_relocs_os->add_output_section_data(incr->relocs_section());
3249 incremental_relocs_os->set_entsize(incr->relocs_entsize());
3251 // Add the .gnu_incremental_got_plt section.
3252 const char* incremental_got_plt_name =
3253 this->namepool_.add(".gnu_incremental_got_plt", false, NULL);
3254 Output_section* incremental_got_plt_os =
3255 this->make_output_section(incremental_got_plt_name,
3256 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0,
3257 ORDER_INVALID, false);
3258 incremental_got_plt_os->add_output_section_data(incr->got_plt_section());
3260 // Add the .gnu_incremental_strtab section.
3261 const char* incremental_strtab_name =
3262 this->namepool_.add(".gnu_incremental_strtab", false, NULL);
3263 Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name,
3264 elfcpp::SHT_STRTAB, 0,
3265 ORDER_INVALID, false);
3266 Output_data_strtab* strtab_data =
3267 new Output_data_strtab(incr->get_stringpool());
3268 incremental_strtab_os->add_output_section_data(strtab_data);
3270 incremental_inputs_os->set_after_input_sections();
3271 incremental_symtab_os->set_after_input_sections();
3272 incremental_relocs_os->set_after_input_sections();
3273 incremental_got_plt_os->set_after_input_sections();
3275 incremental_inputs_os->set_link_section(incremental_strtab_os);
3276 incremental_symtab_os->set_link_section(incremental_inputs_os);
3277 incremental_relocs_os->set_link_section(incremental_inputs_os);
3278 incremental_got_plt_os->set_link_section(incremental_inputs_os);
3281 // Return whether SEG1 should be before SEG2 in the output file. This
3282 // is based entirely on the segment type and flags. When this is
3283 // called the segment addresses have normally not yet been set.
3286 Layout::segment_precedes(const Output_segment* seg1,
3287 const Output_segment* seg2)
3289 elfcpp::Elf_Word type1 = seg1->type();
3290 elfcpp::Elf_Word type2 = seg2->type();
3292 // The single PT_PHDR segment is required to precede any loadable
3293 // segment. We simply make it always first.
3294 if (type1 == elfcpp::PT_PHDR)
3296 gold_assert(type2 != elfcpp::PT_PHDR);
3299 if (type2 == elfcpp::PT_PHDR)
3302 // The single PT_INTERP segment is required to precede any loadable
3303 // segment. We simply make it always second.
3304 if (type1 == elfcpp::PT_INTERP)
3306 gold_assert(type2 != elfcpp::PT_INTERP);
3309 if (type2 == elfcpp::PT_INTERP)
3312 // We then put PT_LOAD segments before any other segments.
3313 if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
3315 if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
3318 // We put the PT_TLS segment last except for the PT_GNU_RELRO
3319 // segment, because that is where the dynamic linker expects to find
3320 // it (this is just for efficiency; other positions would also work
3322 if (type1 == elfcpp::PT_TLS
3323 && type2 != elfcpp::PT_TLS
3324 && type2 != elfcpp::PT_GNU_RELRO)
3326 if (type2 == elfcpp::PT_TLS
3327 && type1 != elfcpp::PT_TLS
3328 && type1 != elfcpp::PT_GNU_RELRO)
3331 // We put the PT_GNU_RELRO segment last, because that is where the
3332 // dynamic linker expects to find it (as with PT_TLS, this is just
3334 if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
3336 if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
3339 const elfcpp::Elf_Word flags1 = seg1->flags();
3340 const elfcpp::Elf_Word flags2 = seg2->flags();
3342 // The order of non-PT_LOAD segments is unimportant. We simply sort
3343 // by the numeric segment type and flags values. There should not
3344 // be more than one segment with the same type and flags, except
3345 // when a linker script specifies such.
3346 if (type1 != elfcpp::PT_LOAD)
3349 return type1 < type2;
3350 gold_assert(flags1 != flags2
3351 || this->script_options_->saw_phdrs_clause());
3352 return flags1 < flags2;
3355 // If the addresses are set already, sort by load address.
3356 if (seg1->are_addresses_set())
3358 if (!seg2->are_addresses_set())
3361 unsigned int section_count1 = seg1->output_section_count();
3362 unsigned int section_count2 = seg2->output_section_count();
3363 if (section_count1 == 0 && section_count2 > 0)
3365 if (section_count1 > 0 && section_count2 == 0)
3368 uint64_t paddr1 = (seg1->are_addresses_set()
3370 : seg1->first_section_load_address());
3371 uint64_t paddr2 = (seg2->are_addresses_set()
3373 : seg2->first_section_load_address());
3375 if (paddr1 != paddr2)
3376 return paddr1 < paddr2;
3378 else if (seg2->are_addresses_set())
3381 // A segment which holds large data comes after a segment which does
3382 // not hold large data.
3383 if (seg1->is_large_data_segment())
3385 if (!seg2->is_large_data_segment())
3388 else if (seg2->is_large_data_segment())
3391 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
3392 // segments come before writable segments. Then writable segments
3393 // with data come before writable segments without data. Then
3394 // executable segments come before non-executable segments. Then
3395 // the unlikely case of a non-readable segment comes before the
3396 // normal case of a readable segment. If there are multiple
3397 // segments with the same type and flags, we require that the
3398 // address be set, and we sort by virtual address and then physical
3400 if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
3401 return (flags1 & elfcpp::PF_W) == 0;
3402 if ((flags1 & elfcpp::PF_W) != 0
3403 && seg1->has_any_data_sections() != seg2->has_any_data_sections())
3404 return seg1->has_any_data_sections();
3405 if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
3406 return (flags1 & elfcpp::PF_X) != 0;
3407 if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
3408 return (flags1 & elfcpp::PF_R) == 0;
3410 // We shouldn't get here--we shouldn't create segments which we
3411 // can't distinguish. Unless of course we are using a weird linker
3412 // script or overlapping --section-start options. We could also get
3413 // here if plugins want unique segments for subsets of sections.
3414 gold_assert(this->script_options_->saw_phdrs_clause()
3415 || parameters->options().any_section_start()
3416 || this->is_unique_segment_for_sections_specified());
3420 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3423 align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
3425 uint64_t unsigned_off = off;
3426 uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
3427 | (addr & (abi_pagesize - 1)));
3428 if (aligned_off < unsigned_off)
3429 aligned_off += abi_pagesize;
3433 // On targets where the text segment contains only executable code,
3434 // a non-executable segment is never the text segment.
3437 is_text_segment(const Target* target, const Output_segment* seg)
3439 elfcpp::Elf_Xword flags = seg->flags();
3440 if ((flags & elfcpp::PF_W) != 0)
3442 if ((flags & elfcpp::PF_X) == 0)
3443 return !target->isolate_execinstr();
3447 // Set the file offsets of all the segments, and all the sections they
3448 // contain. They have all been created. LOAD_SEG must be be laid out
3449 // first. Return the offset of the data to follow.
3452 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
3453 unsigned int* pshndx)
3455 // Sort them into the final order. We use a stable sort so that we
3456 // don't randomize the order of indistinguishable segments created
3457 // by linker scripts.
3458 std::stable_sort(this->segment_list_.begin(), this->segment_list_.end(),
3459 Layout::Compare_segments(this));
3461 // Find the PT_LOAD segments, and set their addresses and offsets
3462 // and their section's addresses and offsets.
3463 uint64_t start_addr;
3464 if (parameters->options().user_set_Ttext())
3465 start_addr = parameters->options().Ttext();
3466 else if (parameters->options().output_is_position_independent())
3469 start_addr = target->default_text_segment_address();
3471 uint64_t addr = start_addr;
3474 // If LOAD_SEG is NULL, then the file header and segment headers
3475 // will not be loadable. But they still need to be at offset 0 in
3476 // the file. Set their offsets now.
3477 if (load_seg == NULL)
3479 for (Data_list::iterator p = this->special_output_list_.begin();
3480 p != this->special_output_list_.end();
3483 off = align_address(off, (*p)->addralign());
3484 (*p)->set_address_and_file_offset(0, off);
3485 off += (*p)->data_size();
3489 unsigned int increase_relro = this->increase_relro_;
3490 if (this->script_options_->saw_sections_clause())
3493 const bool check_sections = parameters->options().check_sections();
3494 Output_segment* last_load_segment = NULL;
3496 unsigned int shndx_begin = *pshndx;
3497 unsigned int shndx_load_seg = *pshndx;
3499 for (Segment_list::iterator p = this->segment_list_.begin();
3500 p != this->segment_list_.end();
3503 if ((*p)->type() == elfcpp::PT_LOAD)
3505 if (target->isolate_execinstr())
3507 // When we hit the segment that should contain the
3508 // file headers, reset the file offset so we place
3509 // it and subsequent segments appropriately.
3510 // We'll fix up the preceding segments below.
3518 shndx_load_seg = *pshndx;
3524 // Verify that the file headers fall into the first segment.
3525 if (load_seg != NULL && load_seg != *p)
3530 bool are_addresses_set = (*p)->are_addresses_set();
3531 if (are_addresses_set)
3533 // When it comes to setting file offsets, we care about
3534 // the physical address.
3535 addr = (*p)->paddr();
3537 else if (parameters->options().user_set_Ttext()
3538 && (parameters->options().omagic()
3539 || is_text_segment(target, *p)))
3541 are_addresses_set = true;
3543 else if (parameters->options().user_set_Trodata_segment()
3544 && ((*p)->flags() & (elfcpp::PF_W | elfcpp::PF_X)) == 0)
3546 addr = parameters->options().Trodata_segment();
3547 are_addresses_set = true;
3549 else if (parameters->options().user_set_Tdata()
3550 && ((*p)->flags() & elfcpp::PF_W) != 0
3551 && (!parameters->options().user_set_Tbss()
3552 || (*p)->has_any_data_sections()))
3554 addr = parameters->options().Tdata();
3555 are_addresses_set = true;
3557 else if (parameters->options().user_set_Tbss()
3558 && ((*p)->flags() & elfcpp::PF_W) != 0
3559 && !(*p)->has_any_data_sections())
3561 addr = parameters->options().Tbss();
3562 are_addresses_set = true;
3565 uint64_t orig_addr = addr;
3566 uint64_t orig_off = off;
3568 uint64_t aligned_addr = 0;
3569 uint64_t abi_pagesize = target->abi_pagesize();
3570 uint64_t common_pagesize = target->common_pagesize();
3572 if (!parameters->options().nmagic()
3573 && !parameters->options().omagic())
3574 (*p)->set_minimum_p_align(abi_pagesize);
3576 if (!are_addresses_set)
3578 // Skip the address forward one page, maintaining the same
3579 // position within the page. This lets us store both segments
3580 // overlapping on a single page in the file, but the loader will
3581 // put them on different pages in memory. We will revisit this
3582 // decision once we know the size of the segment.
3584 uint64_t max_align = (*p)->maximum_alignment();
3585 if (max_align > abi_pagesize)
3586 addr = align_address(addr, max_align);
3587 aligned_addr = addr;
3591 // This is the segment that will contain the file
3592 // headers, so its offset will have to be exactly zero.
3593 gold_assert(orig_off == 0);
3595 // If the target wants a fixed minimum distance from the
3596 // text segment to the read-only segment, move up now.
3598 start_addr + (parameters->options().user_set_rosegment_gap()
3599 ? parameters->options().rosegment_gap()
3600 : target->rosegment_gap());
3601 if (addr < min_addr)
3604 // But this is not the first segment! To make its
3605 // address congruent with its offset, that address better
3606 // be aligned to the ABI-mandated page size.
3607 addr = align_address(addr, abi_pagesize);
3608 aligned_addr = addr;
3612 if ((addr & (abi_pagesize - 1)) != 0)
3613 addr = addr + abi_pagesize;
3615 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3619 if (!parameters->options().nmagic()
3620 && !parameters->options().omagic())
3622 // Here we are also taking care of the case when
3623 // the maximum segment alignment is larger than the page size.
3624 off = align_file_offset(off, addr,
3625 std::max(abi_pagesize,
3626 (*p)->maximum_alignment()));
3630 // This is -N or -n with a section script which prevents
3631 // us from using a load segment. We need to ensure that
3632 // the file offset is aligned to the alignment of the
3633 // segment. This is because the linker script
3634 // implicitly assumed a zero offset. If we don't align
3635 // here, then the alignment of the sections in the
3636 // linker script may not match the alignment of the
3637 // sections in the set_section_addresses call below,
3638 // causing an error about dot moving backward.
3639 off = align_address(off, (*p)->maximum_alignment());
3642 unsigned int shndx_hold = *pshndx;
3643 bool has_relro = false;
3644 uint64_t new_addr = (*p)->set_section_addresses(target, this,
3650 // Now that we know the size of this segment, we may be able
3651 // to save a page in memory, at the cost of wasting some
3652 // file space, by instead aligning to the start of a new
3653 // page. Here we use the real machine page size rather than
3654 // the ABI mandated page size. If the segment has been
3655 // aligned so that the relro data ends at a page boundary,
3656 // we do not try to realign it.
3658 if (!are_addresses_set
3660 && aligned_addr != addr
3661 && !parameters->incremental())
3663 uint64_t first_off = (common_pagesize
3665 & (common_pagesize - 1)));
3666 uint64_t last_off = new_addr & (common_pagesize - 1);
3669 && ((aligned_addr & ~ (common_pagesize - 1))
3670 != (new_addr & ~ (common_pagesize - 1)))
3671 && first_off + last_off <= common_pagesize)
3673 *pshndx = shndx_hold;
3674 addr = align_address(aligned_addr, common_pagesize);
3675 addr = align_address(addr, (*p)->maximum_alignment());
3676 if ((addr & (abi_pagesize - 1)) != 0)
3677 addr = addr + abi_pagesize;
3678 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3679 off = align_file_offset(off, addr, abi_pagesize);
3681 increase_relro = this->increase_relro_;
3682 if (this->script_options_->saw_sections_clause())
3686 new_addr = (*p)->set_section_addresses(target, this,
3696 // Implement --check-sections. We know that the segments
3697 // are sorted by LMA.
3698 if (check_sections && last_load_segment != NULL)
3700 gold_assert(last_load_segment->paddr() <= (*p)->paddr());
3701 if (last_load_segment->paddr() + last_load_segment->memsz()
3704 unsigned long long lb1 = last_load_segment->paddr();
3705 unsigned long long le1 = lb1 + last_load_segment->memsz();
3706 unsigned long long lb2 = (*p)->paddr();
3707 unsigned long long le2 = lb2 + (*p)->memsz();
3708 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3709 "[0x%llx -> 0x%llx]"),
3710 lb1, le1, lb2, le2);
3713 last_load_segment = *p;
3717 if (load_seg != NULL && target->isolate_execinstr())
3719 // Process the early segments again, setting their file offsets
3720 // so they land after the segments starting at LOAD_SEG.
3721 off = align_file_offset(off, 0, target->abi_pagesize());
3723 this->reset_relax_output();
3725 for (Segment_list::iterator p = this->segment_list_.begin();
3729 if ((*p)->type() == elfcpp::PT_LOAD)
3731 // We repeat the whole job of assigning addresses and
3732 // offsets, but we really only want to change the offsets and
3733 // must ensure that the addresses all come out the same as
3734 // they did the first time through.
3735 bool has_relro = false;
3736 const uint64_t old_addr = (*p)->vaddr();
3737 const uint64_t old_end = old_addr + (*p)->memsz();
3738 uint64_t new_addr = (*p)->set_section_addresses(target, this,
3744 gold_assert(new_addr == old_end);
3748 gold_assert(shndx_begin == shndx_load_seg);
3751 // Handle the non-PT_LOAD segments, setting their offsets from their
3752 // section's offsets.
3753 for (Segment_list::iterator p = this->segment_list_.begin();
3754 p != this->segment_list_.end();
3757 // PT_GNU_STACK was set up correctly when it was created.
3758 if ((*p)->type() != elfcpp::PT_LOAD
3759 && (*p)->type() != elfcpp::PT_GNU_STACK)
3760 (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO
3765 // Set the TLS offsets for each section in the PT_TLS segment.
3766 if (this->tls_segment_ != NULL)
3767 this->tls_segment_->set_tls_offsets();
3772 // Set the offsets of all the allocated sections when doing a
3773 // relocatable link. This does the same jobs as set_segment_offsets,
3774 // only for a relocatable link.
3777 Layout::set_relocatable_section_offsets(Output_data* file_header,
3778 unsigned int* pshndx)
3782 file_header->set_address_and_file_offset(0, 0);
3783 off += file_header->data_size();
3785 for (Section_list::iterator p = this->section_list_.begin();
3786 p != this->section_list_.end();
3789 // We skip unallocated sections here, except that group sections
3790 // have to come first.
3791 if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
3792 && (*p)->type() != elfcpp::SHT_GROUP)
3795 off = align_address(off, (*p)->addralign());
3797 // The linker script might have set the address.
3798 if (!(*p)->is_address_valid())
3799 (*p)->set_address(0);
3800 (*p)->set_file_offset(off);
3801 (*p)->finalize_data_size();
3802 if ((*p)->type() != elfcpp::SHT_NOBITS)
3803 off += (*p)->data_size();
3805 (*p)->set_out_shndx(*pshndx);
3812 // Set the file offset of all the sections not associated with a
3816 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
3818 off_t startoff = off;
3821 for (Section_list::iterator p = this->unattached_section_list_.begin();
3822 p != this->unattached_section_list_.end();
3825 // The symtab section is handled in create_symtab_sections.
3826 if (*p == this->symtab_section_)
3829 // If we've already set the data size, don't set it again.
3830 if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
3833 if (pass == BEFORE_INPUT_SECTIONS_PASS
3834 && (*p)->requires_postprocessing())
3836 (*p)->create_postprocessing_buffer();
3837 this->any_postprocessing_sections_ = true;
3840 if (pass == BEFORE_INPUT_SECTIONS_PASS
3841 && (*p)->after_input_sections())
3843 else if (pass == POSTPROCESSING_SECTIONS_PASS
3844 && (!(*p)->after_input_sections()
3845 || (*p)->type() == elfcpp::SHT_STRTAB))
3847 else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3848 && (!(*p)->after_input_sections()
3849 || (*p)->type() != elfcpp::SHT_STRTAB))
3852 if (!parameters->incremental_update())
3854 off = align_address(off, (*p)->addralign());
3855 (*p)->set_file_offset(off);
3856 (*p)->finalize_data_size();
3860 // Incremental update: allocate file space from free list.
3861 (*p)->pre_finalize_data_size();
3862 off_t current_size = (*p)->current_data_size();
3863 off = this->allocate(current_size, (*p)->addralign(), startoff);
3866 if (is_debugging_enabled(DEBUG_INCREMENTAL))
3867 this->free_list_.dump();
3868 gold_assert((*p)->output_section() != NULL);
3869 gold_fallback(_("out of patch space for section %s; "
3870 "relink with --incremental-full"),
3871 (*p)->output_section()->name());
3873 (*p)->set_file_offset(off);
3874 (*p)->finalize_data_size();
3875 if ((*p)->data_size() > current_size)
3877 gold_assert((*p)->output_section() != NULL);
3878 gold_fallback(_("%s: section changed size; "
3879 "relink with --incremental-full"),
3880 (*p)->output_section()->name());
3882 gold_debug(DEBUG_INCREMENTAL,
3883 "set_section_offsets: %08lx %08lx %s",
3884 static_cast<long>(off),
3885 static_cast<long>((*p)->data_size()),
3886 ((*p)->output_section() != NULL
3887 ? (*p)->output_section()->name() : "(special)"));
3890 off += (*p)->data_size();
3894 // At this point the name must be set.
3895 if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
3896 this->namepool_.add((*p)->name(), false, NULL);
3901 // Set the section indexes of all the sections not associated with a
3905 Layout::set_section_indexes(unsigned int shndx)
3907 for (Section_list::iterator p = this->unattached_section_list_.begin();
3908 p != this->unattached_section_list_.end();
3911 if (!(*p)->has_out_shndx())
3913 (*p)->set_out_shndx(shndx);
3920 // Set the section addresses according to the linker script. This is
3921 // only called when we see a SECTIONS clause. This returns the
3922 // program segment which should hold the file header and segment
3923 // headers, if any. It will return NULL if they should not be in a
3927 Layout::set_section_addresses_from_script(Symbol_table* symtab)
3929 Script_sections* ss = this->script_options_->script_sections();
3930 gold_assert(ss->saw_sections_clause());
3931 return this->script_options_->set_section_addresses(symtab, this);
3934 // Place the orphan sections in the linker script.
3937 Layout::place_orphan_sections_in_script()
3939 Script_sections* ss = this->script_options_->script_sections();
3940 gold_assert(ss->saw_sections_clause());
3942 // Place each orphaned output section in the script.
3943 for (Section_list::iterator p = this->section_list_.begin();
3944 p != this->section_list_.end();
3947 if (!(*p)->found_in_sections_clause())
3948 ss->place_orphan(*p);
3952 // Count the local symbols in the regular symbol table and the dynamic
3953 // symbol table, and build the respective string pools.
3956 Layout::count_local_symbols(const Task* task,
3957 const Input_objects* input_objects)
3959 // First, figure out an upper bound on the number of symbols we'll
3960 // be inserting into each pool. This helps us create the pools with
3961 // the right size, to avoid unnecessary hashtable resizing.
3962 unsigned int symbol_count = 0;
3963 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3964 p != input_objects->relobj_end();
3966 symbol_count += (*p)->local_symbol_count();
3968 // Go from "upper bound" to "estimate." We overcount for two
3969 // reasons: we double-count symbols that occur in more than one
3970 // object file, and we count symbols that are dropped from the
3971 // output. Add it all together and assume we overcount by 100%.
3974 // We assume all symbols will go into both the sympool and dynpool.
3975 this->sympool_.reserve(symbol_count);
3976 this->dynpool_.reserve(symbol_count);
3978 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3979 p != input_objects->relobj_end();
3982 Task_lock_obj<Object> tlo(task, *p);
3983 (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
3987 // Create the symbol table sections. Here we also set the final
3988 // values of the symbols. At this point all the loadable sections are
3989 // fully laid out. SHNUM is the number of sections so far.
3992 Layout::create_symtab_sections(const Input_objects* input_objects,
3993 Symbol_table* symtab,
3999 if (parameters->target().get_size() == 32)
4001 symsize = elfcpp::Elf_sizes<32>::sym_size;
4004 else if (parameters->target().get_size() == 64)
4006 symsize = elfcpp::Elf_sizes<64>::sym_size;
4012 // Compute file offsets relative to the start of the symtab section.
4015 // Save space for the dummy symbol at the start of the section. We
4016 // never bother to write this out--it will just be left as zero.
4018 unsigned int local_symbol_index = 1;
4020 // Add STT_SECTION symbols for each Output section which needs one.
4021 for (Section_list::iterator p = this->section_list_.begin();
4022 p != this->section_list_.end();
4025 if (!(*p)->needs_symtab_index())
4026 (*p)->set_symtab_index(-1U);
4029 (*p)->set_symtab_index(local_symbol_index);
4030 ++local_symbol_index;
4035 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4036 p != input_objects->relobj_end();
4039 unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
4041 off += (index - local_symbol_index) * symsize;
4042 local_symbol_index = index;
4045 unsigned int local_symcount = local_symbol_index;
4046 gold_assert(static_cast<off_t>(local_symcount * symsize) == off);
4049 size_t dyn_global_index;
4051 if (this->dynsym_section_ == NULL)
4054 dyn_global_index = 0;
4059 dyn_global_index = this->dynsym_section_->info();
4060 off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
4061 dynoff = this->dynsym_section_->offset() + locsize;
4062 dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
4063 gold_assert(static_cast<off_t>(dyncount * symsize)
4064 == this->dynsym_section_->data_size() - locsize);
4067 off_t global_off = off;
4068 off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
4069 &this->sympool_, &local_symcount);
4071 if (!parameters->options().strip_all())
4073 this->sympool_.set_string_offsets();
4075 const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
4076 Output_section* osymtab = this->make_output_section(symtab_name,
4080 this->symtab_section_ = osymtab;
4082 Output_section_data* pos = new Output_data_fixed_space(off, align,
4084 osymtab->add_output_section_data(pos);
4086 // We generate a .symtab_shndx section if we have more than
4087 // SHN_LORESERVE sections. Technically it is possible that we
4088 // don't need one, because it is possible that there are no
4089 // symbols in any of sections with indexes larger than
4090 // SHN_LORESERVE. That is probably unusual, though, and it is
4091 // easier to always create one than to compute section indexes
4092 // twice (once here, once when writing out the symbols).
4093 if (shnum >= elfcpp::SHN_LORESERVE)
4095 const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
4097 Output_section* osymtab_xindex =
4098 this->make_output_section(symtab_xindex_name,
4099 elfcpp::SHT_SYMTAB_SHNDX, 0,
4100 ORDER_INVALID, false);
4102 size_t symcount = off / symsize;
4103 this->symtab_xindex_ = new Output_symtab_xindex(symcount);
4105 osymtab_xindex->add_output_section_data(this->symtab_xindex_);
4107 osymtab_xindex->set_link_section(osymtab);
4108 osymtab_xindex->set_addralign(4);
4109 osymtab_xindex->set_entsize(4);
4111 osymtab_xindex->set_after_input_sections();
4113 // This tells the driver code to wait until the symbol table
4114 // has written out before writing out the postprocessing
4115 // sections, including the .symtab_shndx section.
4116 this->any_postprocessing_sections_ = true;
4119 const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
4120 Output_section* ostrtab = this->make_output_section(strtab_name,
4125 Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
4126 ostrtab->add_output_section_data(pstr);
4129 if (!parameters->incremental_update())
4130 symtab_off = align_address(*poff, align);
4133 symtab_off = this->allocate(off, align, *poff);
4135 gold_fallback(_("out of patch space for symbol table; "
4136 "relink with --incremental-full"));
4137 gold_debug(DEBUG_INCREMENTAL,
4138 "create_symtab_sections: %08lx %08lx .symtab",
4139 static_cast<long>(symtab_off),
4140 static_cast<long>(off));
4143 symtab->set_file_offset(symtab_off + global_off);
4144 osymtab->set_file_offset(symtab_off);
4145 osymtab->finalize_data_size();
4146 osymtab->set_link_section(ostrtab);
4147 osymtab->set_info(local_symcount);
4148 osymtab->set_entsize(symsize);
4150 if (symtab_off + off > *poff)
4151 *poff = symtab_off + off;
4155 // Create the .shstrtab section, which holds the names of the
4156 // sections. At the time this is called, we have created all the
4157 // output sections except .shstrtab itself.
4160 Layout::create_shstrtab()
4162 // FIXME: We don't need to create a .shstrtab section if we are
4163 // stripping everything.
4165 const char* name = this->namepool_.add(".shstrtab", false, NULL);
4167 Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0,
4168 ORDER_INVALID, false);
4170 if (strcmp(parameters->options().compress_debug_sections(), "none") != 0)
4172 // We can't write out this section until we've set all the
4173 // section names, and we don't set the names of compressed
4174 // output sections until relocations are complete. FIXME: With
4175 // the current names we use, this is unnecessary.
4176 os->set_after_input_sections();
4179 Output_section_data* posd = new Output_data_strtab(&this->namepool_);
4180 os->add_output_section_data(posd);
4185 // Create the section headers. SIZE is 32 or 64. OFF is the file
4189 Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
4191 Output_section_headers* oshdrs;
4192 oshdrs = new Output_section_headers(this,
4193 &this->segment_list_,
4194 &this->section_list_,
4195 &this->unattached_section_list_,
4199 if (!parameters->incremental_update())
4200 off = align_address(*poff, oshdrs->addralign());
4203 oshdrs->pre_finalize_data_size();
4204 off = this->allocate(oshdrs->data_size(), oshdrs->addralign(), *poff);
4206 gold_fallback(_("out of patch space for section header table; "
4207 "relink with --incremental-full"));
4208 gold_debug(DEBUG_INCREMENTAL,
4209 "create_shdrs: %08lx %08lx (section header table)",
4210 static_cast<long>(off),
4211 static_cast<long>(off + oshdrs->data_size()));
4213 oshdrs->set_address_and_file_offset(0, off);
4214 off += oshdrs->data_size();
4217 this->section_headers_ = oshdrs;
4220 // Count the allocated sections.
4223 Layout::allocated_output_section_count() const
4225 size_t section_count = 0;
4226 for (Segment_list::const_iterator p = this->segment_list_.begin();
4227 p != this->segment_list_.end();
4229 section_count += (*p)->output_section_count();
4230 return section_count;
4233 // Create the dynamic symbol table.
4236 Layout::create_dynamic_symtab(const Input_objects* input_objects,
4237 Symbol_table* symtab,
4238 Output_section** pdynstr,
4239 unsigned int* plocal_dynamic_count,
4240 std::vector<Symbol*>* pdynamic_symbols,
4241 Versions* pversions)
4243 // Count all the symbols in the dynamic symbol table, and set the
4244 // dynamic symbol indexes.
4246 // Skip symbol 0, which is always all zeroes.
4247 unsigned int index = 1;
4249 // Add STT_SECTION symbols for each Output section which needs one.
4250 for (Section_list::iterator p = this->section_list_.begin();
4251 p != this->section_list_.end();
4254 if (!(*p)->needs_dynsym_index())
4255 (*p)->set_dynsym_index(-1U);
4258 (*p)->set_dynsym_index(index);
4263 // Count the local symbols that need to go in the dynamic symbol table,
4264 // and set the dynamic symbol indexes.
4265 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4266 p != input_objects->relobj_end();
4269 unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
4273 unsigned int local_symcount = index;
4274 *plocal_dynamic_count = local_symcount;
4276 index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
4277 &this->dynpool_, pversions);
4281 const int size = parameters->target().get_size();
4284 symsize = elfcpp::Elf_sizes<32>::sym_size;
4287 else if (size == 64)
4289 symsize = elfcpp::Elf_sizes<64>::sym_size;
4295 // Create the dynamic symbol table section.
4297 Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
4301 ORDER_DYNAMIC_LINKER,
4304 // Check for NULL as a linker script may discard .dynsym.
4307 Output_section_data* odata = new Output_data_fixed_space(index * symsize,
4310 dynsym->add_output_section_data(odata);
4312 dynsym->set_info(local_symcount);
4313 dynsym->set_entsize(symsize);
4314 dynsym->set_addralign(align);
4316 this->dynsym_section_ = dynsym;
4319 Output_data_dynamic* const odyn = this->dynamic_data_;
4322 odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
4323 odyn->add_constant(elfcpp::DT_SYMENT, symsize);
4326 // If there are more than SHN_LORESERVE allocated sections, we
4327 // create a .dynsym_shndx section. It is possible that we don't
4328 // need one, because it is possible that there are no dynamic
4329 // symbols in any of the sections with indexes larger than
4330 // SHN_LORESERVE. This is probably unusual, though, and at this
4331 // time we don't know the actual section indexes so it is
4332 // inconvenient to check.
4333 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
4335 Output_section* dynsym_xindex =
4336 this->choose_output_section(NULL, ".dynsym_shndx",
4337 elfcpp::SHT_SYMTAB_SHNDX,
4339 false, ORDER_DYNAMIC_LINKER, false, false);
4341 if (dynsym_xindex != NULL)
4343 this->dynsym_xindex_ = new Output_symtab_xindex(index);
4345 dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
4347 dynsym_xindex->set_link_section(dynsym);
4348 dynsym_xindex->set_addralign(4);
4349 dynsym_xindex->set_entsize(4);
4351 dynsym_xindex->set_after_input_sections();
4353 // This tells the driver code to wait until the symbol table
4354 // has written out before writing out the postprocessing
4355 // sections, including the .dynsym_shndx section.
4356 this->any_postprocessing_sections_ = true;
4360 // Create the dynamic string table section.
4362 Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
4366 ORDER_DYNAMIC_LINKER,
4371 Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
4372 dynstr->add_output_section_data(strdata);
4375 dynsym->set_link_section(dynstr);
4376 if (this->dynamic_section_ != NULL)
4377 this->dynamic_section_->set_link_section(dynstr);
4381 odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
4382 odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
4386 // Create the hash tables. The Gnu-style hash table must be
4387 // built first, because it changes the order of the symbols
4388 // in the dynamic symbol table.
4390 if (strcmp(parameters->options().hash_style(), "gnu") == 0
4391 || strcmp(parameters->options().hash_style(), "both") == 0)
4393 unsigned char* phash;
4394 unsigned int hashlen;
4395 Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
4398 Output_section* hashsec =
4399 this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH,
4400 elfcpp::SHF_ALLOC, false,
4401 ORDER_DYNAMIC_LINKER, false, false);
4403 Output_section_data* hashdata = new Output_data_const_buffer(phash,
4407 if (hashsec != NULL && hashdata != NULL)
4408 hashsec->add_output_section_data(hashdata);
4410 if (hashsec != NULL)
4413 hashsec->set_link_section(dynsym);
4415 // For a 64-bit target, the entries in .gnu.hash do not have
4416 // a uniform size, so we only set the entry size for a
4418 if (parameters->target().get_size() == 32)
4419 hashsec->set_entsize(4);
4422 odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
4426 if (strcmp(parameters->options().hash_style(), "sysv") == 0
4427 || strcmp(parameters->options().hash_style(), "both") == 0)
4429 unsigned char* phash;
4430 unsigned int hashlen;
4431 Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
4434 Output_section* hashsec =
4435 this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH,
4436 elfcpp::SHF_ALLOC, false,
4437 ORDER_DYNAMIC_LINKER, false, false);
4439 Output_section_data* hashdata = new Output_data_const_buffer(phash,
4443 if (hashsec != NULL && hashdata != NULL)
4444 hashsec->add_output_section_data(hashdata);
4446 if (hashsec != NULL)
4449 hashsec->set_link_section(dynsym);
4450 hashsec->set_entsize(parameters->target().hash_entry_size() / 8);
4454 odyn->add_section_address(elfcpp::DT_HASH, hashsec);
4458 // Assign offsets to each local portion of the dynamic symbol table.
4461 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
4463 Output_section* dynsym = this->dynsym_section_;
4467 off_t off = dynsym->offset();
4469 // Skip the dummy symbol at the start of the section.
4470 off += dynsym->entsize();
4472 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4473 p != input_objects->relobj_end();
4476 unsigned int count = (*p)->set_local_dynsym_offset(off);
4477 off += count * dynsym->entsize();
4481 // Create the version sections.
4484 Layout::create_version_sections(const Versions* versions,
4485 const Symbol_table* symtab,
4486 unsigned int local_symcount,
4487 const std::vector<Symbol*>& dynamic_symbols,
4488 const Output_section* dynstr)
4490 if (!versions->any_defs() && !versions->any_needs())
4493 switch (parameters->size_and_endianness())
4495 #ifdef HAVE_TARGET_32_LITTLE
4496 case Parameters::TARGET_32_LITTLE:
4497 this->sized_create_version_sections<32, false>(versions, symtab,
4499 dynamic_symbols, dynstr);
4502 #ifdef HAVE_TARGET_32_BIG
4503 case Parameters::TARGET_32_BIG:
4504 this->sized_create_version_sections<32, true>(versions, symtab,
4506 dynamic_symbols, dynstr);
4509 #ifdef HAVE_TARGET_64_LITTLE
4510 case Parameters::TARGET_64_LITTLE:
4511 this->sized_create_version_sections<64, false>(versions, symtab,
4513 dynamic_symbols, dynstr);
4516 #ifdef HAVE_TARGET_64_BIG
4517 case Parameters::TARGET_64_BIG:
4518 this->sized_create_version_sections<64, true>(versions, symtab,
4520 dynamic_symbols, dynstr);
4528 // Create the version sections, sized version.
4530 template<int size, bool big_endian>
4532 Layout::sized_create_version_sections(
4533 const Versions* versions,
4534 const Symbol_table* symtab,
4535 unsigned int local_symcount,
4536 const std::vector<Symbol*>& dynamic_symbols,
4537 const Output_section* dynstr)
4539 Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
4540 elfcpp::SHT_GNU_versym,
4543 ORDER_DYNAMIC_LINKER,
4546 // Check for NULL since a linker script may discard this section.
4549 unsigned char* vbuf;
4551 versions->symbol_section_contents<size, big_endian>(symtab,
4557 Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
4560 vsec->add_output_section_data(vdata);
4561 vsec->set_entsize(2);
4562 vsec->set_link_section(this->dynsym_section_);
4565 Output_data_dynamic* const odyn = this->dynamic_data_;
4566 if (odyn != NULL && vsec != NULL)
4567 odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
4569 if (versions->any_defs())
4571 Output_section* vdsec;
4572 vdsec = this->choose_output_section(NULL, ".gnu.version_d",
4573 elfcpp::SHT_GNU_verdef,
4575 false, ORDER_DYNAMIC_LINKER, false,
4580 unsigned char* vdbuf;
4581 unsigned int vdsize;
4582 unsigned int vdentries;
4583 versions->def_section_contents<size, big_endian>(&this->dynpool_,
4587 Output_section_data* vddata =
4588 new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
4590 vdsec->add_output_section_data(vddata);
4591 vdsec->set_link_section(dynstr);
4592 vdsec->set_info(vdentries);
4596 odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
4597 odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
4602 if (versions->any_needs())
4604 Output_section* vnsec;
4605 vnsec = this->choose_output_section(NULL, ".gnu.version_r",
4606 elfcpp::SHT_GNU_verneed,
4608 false, ORDER_DYNAMIC_LINKER, false,
4613 unsigned char* vnbuf;
4614 unsigned int vnsize;
4615 unsigned int vnentries;
4616 versions->need_section_contents<size, big_endian>(&this->dynpool_,
4620 Output_section_data* vndata =
4621 new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
4623 vnsec->add_output_section_data(vndata);
4624 vnsec->set_link_section(dynstr);
4625 vnsec->set_info(vnentries);
4629 odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
4630 odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
4636 // Create the .interp section and PT_INTERP segment.
4639 Layout::create_interp(const Target* target)
4641 gold_assert(this->interp_segment_ == NULL);
4643 const char* interp = parameters->options().dynamic_linker();
4646 interp = target->dynamic_linker();
4647 gold_assert(interp != NULL);
4650 size_t len = strlen(interp) + 1;
4652 Output_section_data* odata = new Output_data_const(interp, len, 1);
4654 Output_section* osec = this->choose_output_section(NULL, ".interp",
4655 elfcpp::SHT_PROGBITS,
4657 false, ORDER_INTERP,
4660 osec->add_output_section_data(odata);
4663 // Add dynamic tags for the PLT and the dynamic relocs. This is
4664 // called by the target-specific code. This does nothing if not doing
4667 // USE_REL is true for REL relocs rather than RELA relocs.
4669 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
4671 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
4672 // and we also set DT_PLTREL. We use PLT_REL's output section, since
4673 // some targets have multiple reloc sections in PLT_REL.
4675 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
4676 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
4679 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
4683 Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
4684 const Output_data* plt_rel,
4685 const Output_data_reloc_generic* dyn_rel,
4686 bool add_debug, bool dynrel_includes_plt)
4688 Output_data_dynamic* odyn = this->dynamic_data_;
4692 if (plt_got != NULL && plt_got->output_section() != NULL)
4693 odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got);
4695 if (plt_rel != NULL && plt_rel->output_section() != NULL)
4697 odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section());
4698 odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section());
4699 odyn->add_constant(elfcpp::DT_PLTREL,
4700 use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA);
4703 if ((dyn_rel != NULL && dyn_rel->output_section() != NULL)
4704 || (dynrel_includes_plt
4706 && plt_rel->output_section() != NULL))
4708 bool have_dyn_rel = dyn_rel != NULL && dyn_rel->output_section() != NULL;
4709 bool have_plt_rel = plt_rel != NULL && plt_rel->output_section() != NULL;
4710 odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
4712 ? dyn_rel->output_section()
4713 : plt_rel->output_section()));
4714 elfcpp::DT size_tag = use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ;
4715 if (have_dyn_rel && have_plt_rel && dynrel_includes_plt)
4716 odyn->add_section_size(size_tag,
4717 dyn_rel->output_section(),
4718 plt_rel->output_section());
4719 else if (have_dyn_rel)
4720 odyn->add_section_size(size_tag, dyn_rel->output_section());
4722 odyn->add_section_size(size_tag, plt_rel->output_section());
4723 const int size = parameters->target().get_size();
4728 rel_tag = elfcpp::DT_RELENT;
4730 rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size;
4731 else if (size == 64)
4732 rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size;
4738 rel_tag = elfcpp::DT_RELAENT;
4740 rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size;
4741 else if (size == 64)
4742 rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size;
4746 odyn->add_constant(rel_tag, rel_size);
4748 if (parameters->options().combreloc() && have_dyn_rel)
4750 size_t c = dyn_rel->relative_reloc_count();
4752 odyn->add_constant((use_rel
4753 ? elfcpp::DT_RELCOUNT
4754 : elfcpp::DT_RELACOUNT),
4759 if (add_debug && !parameters->options().shared())
4761 // The value of the DT_DEBUG tag is filled in by the dynamic
4762 // linker at run time, and used by the debugger.
4763 odyn->add_constant(elfcpp::DT_DEBUG, 0);
4768 Layout::add_target_specific_dynamic_tag(elfcpp::DT tag, unsigned int val)
4770 Output_data_dynamic* odyn = this->dynamic_data_;
4773 odyn->add_constant(tag, val);
4776 // Finish the .dynamic section and PT_DYNAMIC segment.
4779 Layout::finish_dynamic_section(const Input_objects* input_objects,
4780 const Symbol_table* symtab)
4782 if (!this->script_options_->saw_phdrs_clause()
4783 && this->dynamic_section_ != NULL)
4785 Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
4788 oseg->add_output_section_to_nonload(this->dynamic_section_,
4789 elfcpp::PF_R | elfcpp::PF_W);
4792 Output_data_dynamic* const odyn = this->dynamic_data_;
4796 for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
4797 p != input_objects->dynobj_end();
4800 if (!(*p)->is_needed() && (*p)->as_needed())
4802 // This dynamic object was linked with --as-needed, but it
4807 odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
4810 if (parameters->options().shared())
4812 const char* soname = parameters->options().soname();
4814 odyn->add_string(elfcpp::DT_SONAME, soname);
4817 Symbol* sym = symtab->lookup(parameters->options().init());
4818 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4819 odyn->add_symbol(elfcpp::DT_INIT, sym);
4821 sym = symtab->lookup(parameters->options().fini());
4822 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4823 odyn->add_symbol(elfcpp::DT_FINI, sym);
4825 // Look for .init_array, .preinit_array and .fini_array by checking
4827 for(Layout::Section_list::const_iterator p = this->section_list_.begin();
4828 p != this->section_list_.end();
4830 switch((*p)->type())
4832 case elfcpp::SHT_FINI_ARRAY:
4833 odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p);
4834 odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p);
4836 case elfcpp::SHT_INIT_ARRAY:
4837 odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p);
4838 odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p);
4840 case elfcpp::SHT_PREINIT_ARRAY:
4841 odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p);
4842 odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p);
4848 // Add a DT_RPATH entry if needed.
4849 const General_options::Dir_list& rpath(parameters->options().rpath());
4852 std::string rpath_val;
4853 for (General_options::Dir_list::const_iterator p = rpath.begin();
4857 if (rpath_val.empty())
4858 rpath_val = p->name();
4861 // Eliminate duplicates.
4862 General_options::Dir_list::const_iterator q;
4863 for (q = rpath.begin(); q != p; ++q)
4864 if (q->name() == p->name())
4869 rpath_val += p->name();
4874 if (!parameters->options().enable_new_dtags())
4875 odyn->add_string(elfcpp::DT_RPATH, rpath_val);
4877 odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
4880 // Look for text segments that have dynamic relocations.
4881 bool have_textrel = false;
4882 if (!this->script_options_->saw_sections_clause())
4884 for (Segment_list::const_iterator p = this->segment_list_.begin();
4885 p != this->segment_list_.end();
4888 if ((*p)->type() == elfcpp::PT_LOAD
4889 && ((*p)->flags() & elfcpp::PF_W) == 0
4890 && (*p)->has_dynamic_reloc())
4892 have_textrel = true;
4899 // We don't know the section -> segment mapping, so we are
4900 // conservative and just look for readonly sections with
4901 // relocations. If those sections wind up in writable segments,
4902 // then we have created an unnecessary DT_TEXTREL entry.
4903 for (Section_list::const_iterator p = this->section_list_.begin();
4904 p != this->section_list_.end();
4907 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
4908 && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
4909 && (*p)->has_dynamic_reloc())
4911 have_textrel = true;
4917 if (parameters->options().filter() != NULL)
4918 odyn->add_string(elfcpp::DT_FILTER, parameters->options().filter());
4919 if (parameters->options().any_auxiliary())
4921 for (options::String_set::const_iterator p =
4922 parameters->options().auxiliary_begin();
4923 p != parameters->options().auxiliary_end();
4925 odyn->add_string(elfcpp::DT_AUXILIARY, *p);
4928 // Add a DT_FLAGS entry if necessary.
4929 unsigned int flags = 0;
4932 // Add a DT_TEXTREL for compatibility with older loaders.
4933 odyn->add_constant(elfcpp::DT_TEXTREL, 0);
4934 flags |= elfcpp::DF_TEXTREL;
4936 if (parameters->options().text())
4937 gold_error(_("read-only segment has dynamic relocations"));
4938 else if (parameters->options().warn_shared_textrel()
4939 && parameters->options().shared())
4940 gold_warning(_("shared library text segment is not shareable"));
4942 if (parameters->options().shared() && this->has_static_tls())
4943 flags |= elfcpp::DF_STATIC_TLS;
4944 if (parameters->options().origin())
4945 flags |= elfcpp::DF_ORIGIN;
4946 if (parameters->options().Bsymbolic()
4947 && !parameters->options().have_dynamic_list())
4949 flags |= elfcpp::DF_SYMBOLIC;
4950 // Add DT_SYMBOLIC for compatibility with older loaders.
4951 odyn->add_constant(elfcpp::DT_SYMBOLIC, 0);
4953 if (parameters->options().now())
4954 flags |= elfcpp::DF_BIND_NOW;
4956 odyn->add_constant(elfcpp::DT_FLAGS, flags);
4959 if (parameters->options().global())
4960 flags |= elfcpp::DF_1_GLOBAL;
4961 if (parameters->options().initfirst())
4962 flags |= elfcpp::DF_1_INITFIRST;
4963 if (parameters->options().interpose())
4964 flags |= elfcpp::DF_1_INTERPOSE;
4965 if (parameters->options().loadfltr())
4966 flags |= elfcpp::DF_1_LOADFLTR;
4967 if (parameters->options().nodefaultlib())
4968 flags |= elfcpp::DF_1_NODEFLIB;
4969 if (parameters->options().nodelete())
4970 flags |= elfcpp::DF_1_NODELETE;
4971 if (parameters->options().nodlopen())
4972 flags |= elfcpp::DF_1_NOOPEN;
4973 if (parameters->options().nodump())
4974 flags |= elfcpp::DF_1_NODUMP;
4975 if (!parameters->options().shared())
4976 flags &= ~(elfcpp::DF_1_INITFIRST
4977 | elfcpp::DF_1_NODELETE
4978 | elfcpp::DF_1_NOOPEN);
4979 if (parameters->options().origin())
4980 flags |= elfcpp::DF_1_ORIGIN;
4981 if (parameters->options().now())
4982 flags |= elfcpp::DF_1_NOW;
4983 if (parameters->options().Bgroup())
4984 flags |= elfcpp::DF_1_GROUP;
4986 odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
4989 // Set the size of the _DYNAMIC symbol table to be the size of the
4993 Layout::set_dynamic_symbol_size(const Symbol_table* symtab)
4995 Output_data_dynamic* const odyn = this->dynamic_data_;
4998 odyn->finalize_data_size();
4999 if (this->dynamic_symbol_ == NULL)
5001 off_t data_size = odyn->data_size();
5002 const int size = parameters->target().get_size();
5004 symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size);
5005 else if (size == 64)
5006 symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size);
5011 // The mapping of input section name prefixes to output section names.
5012 // In some cases one prefix is itself a prefix of another prefix; in
5013 // such a case the longer prefix must come first. These prefixes are
5014 // based on the GNU linker default ELF linker script.
5016 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
5017 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
5018 const Layout::Section_name_mapping Layout::section_name_mapping[] =
5020 MAPPING_INIT(".text.", ".text"),
5021 MAPPING_INIT(".rodata.", ".rodata"),
5022 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
5023 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
5024 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
5025 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
5026 MAPPING_INIT(".data.", ".data"),
5027 MAPPING_INIT(".bss.", ".bss"),
5028 MAPPING_INIT(".tdata.", ".tdata"),
5029 MAPPING_INIT(".tbss.", ".tbss"),
5030 MAPPING_INIT(".init_array.", ".init_array"),
5031 MAPPING_INIT(".fini_array.", ".fini_array"),
5032 MAPPING_INIT(".sdata.", ".sdata"),
5033 MAPPING_INIT(".sbss.", ".sbss"),
5034 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
5035 // differently depending on whether it is creating a shared library.
5036 MAPPING_INIT(".sdata2.", ".sdata"),
5037 MAPPING_INIT(".sbss2.", ".sbss"),
5038 MAPPING_INIT(".lrodata.", ".lrodata"),
5039 MAPPING_INIT(".ldata.", ".ldata"),
5040 MAPPING_INIT(".lbss.", ".lbss"),
5041 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
5042 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
5043 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
5044 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
5045 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
5046 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
5047 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
5048 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
5049 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
5050 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
5051 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
5052 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
5053 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
5054 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
5055 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
5056 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
5057 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
5058 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
5059 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
5060 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
5061 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
5064 #undef MAPPING_INIT_EXACT
5066 const int Layout::section_name_mapping_count =
5067 (sizeof(Layout::section_name_mapping)
5068 / sizeof(Layout::section_name_mapping[0]));
5070 // Choose the output section name to use given an input section name.
5071 // Set *PLEN to the length of the name. *PLEN is initialized to the
5075 Layout::output_section_name(const Relobj* relobj, const char* name,
5078 // gcc 4.3 generates the following sorts of section names when it
5079 // needs a section name specific to a function:
5085 // .data.rel.local.FN
5087 // .data.rel.ro.local.FN
5094 // The GNU linker maps all of those to the part before the .FN,
5095 // except that .data.rel.local.FN is mapped to .data, and
5096 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
5097 // beginning with .data.rel.ro.local are grouped together.
5099 // For an anonymous namespace, the string FN can contain a '.'.
5101 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
5102 // GNU linker maps to .rodata.
5104 // The .data.rel.ro sections are used with -z relro. The sections
5105 // are recognized by name. We use the same names that the GNU
5106 // linker does for these sections.
5108 // It is hard to handle this in a principled way, so we don't even
5109 // try. We use a table of mappings. If the input section name is
5110 // not found in the table, we simply use it as the output section
5113 const Section_name_mapping* psnm = section_name_mapping;
5114 for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
5116 if (psnm->fromlen > 0)
5118 if (strncmp(name, psnm->from, psnm->fromlen) == 0)
5120 *plen = psnm->tolen;
5126 if (strcmp(name, psnm->from) == 0)
5128 *plen = psnm->tolen;
5134 // As an additional complication, .ctors sections are output in
5135 // either .ctors or .init_array sections, and .dtors sections are
5136 // output in either .dtors or .fini_array sections.
5137 if (is_prefix_of(".ctors.", name) || is_prefix_of(".dtors.", name))
5139 if (parameters->options().ctors_in_init_array())
5142 return name[1] == 'c' ? ".init_array" : ".fini_array";
5147 return name[1] == 'c' ? ".ctors" : ".dtors";
5150 if (parameters->options().ctors_in_init_array()
5151 && (strcmp(name, ".ctors") == 0 || strcmp(name, ".dtors") == 0))
5153 // To make .init_array/.fini_array work with gcc we must exclude
5154 // .ctors and .dtors sections from the crtbegin and crtend
5157 || (!Layout::match_file_name(relobj, "crtbegin")
5158 && !Layout::match_file_name(relobj, "crtend")))
5161 return name[1] == 'c' ? ".init_array" : ".fini_array";
5168 // Return true if RELOBJ is an input file whose base name matches
5169 // FILE_NAME. The base name must have an extension of ".o", and must
5170 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
5171 // to match crtbegin.o as well as crtbeginS.o without getting confused
5172 // by other possibilities. Overall matching the file name this way is
5173 // a dreadful hack, but the GNU linker does it in order to better
5174 // support gcc, and we need to be compatible.
5177 Layout::match_file_name(const Relobj* relobj, const char* match)
5179 const std::string& file_name(relobj->name());
5180 const char* base_name = lbasename(file_name.c_str());
5181 size_t match_len = strlen(match);
5182 if (strncmp(base_name, match, match_len) != 0)
5184 size_t base_len = strlen(base_name);
5185 if (base_len != match_len + 2 && base_len != match_len + 3)
5187 return memcmp(base_name + base_len - 2, ".o", 2) == 0;
5190 // Check if a comdat group or .gnu.linkonce section with the given
5191 // NAME is selected for the link. If there is already a section,
5192 // *KEPT_SECTION is set to point to the existing section and the
5193 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
5194 // IS_GROUP_NAME are recorded for this NAME in the layout object,
5195 // *KEPT_SECTION is set to the internal copy and the function returns
5199 Layout::find_or_add_kept_section(const std::string& name,
5204 Kept_section** kept_section)
5206 // It's normal to see a couple of entries here, for the x86 thunk
5207 // sections. If we see more than a few, we're linking a C++
5208 // program, and we resize to get more space to minimize rehashing.
5209 if (this->signatures_.size() > 4
5210 && !this->resized_signatures_)
5212 reserve_unordered_map(&this->signatures_,
5213 this->number_of_input_files_ * 64);
5214 this->resized_signatures_ = true;
5217 Kept_section candidate;
5218 std::pair<Signatures::iterator, bool> ins =
5219 this->signatures_.insert(std::make_pair(name, candidate));
5221 if (kept_section != NULL)
5222 *kept_section = &ins.first->second;
5225 // This is the first time we've seen this signature.
5226 ins.first->second.set_object(object);
5227 ins.first->second.set_shndx(shndx);
5229 ins.first->second.set_is_comdat();
5231 ins.first->second.set_is_group_name();
5235 // We have already seen this signature.
5237 if (ins.first->second.is_group_name())
5239 // We've already seen a real section group with this signature.
5240 // If the kept group is from a plugin object, and we're in the
5241 // replacement phase, accept the new one as a replacement.
5242 if (ins.first->second.object() == NULL
5243 && parameters->options().plugins()->in_replacement_phase())
5245 ins.first->second.set_object(object);
5246 ins.first->second.set_shndx(shndx);
5251 else if (is_group_name)
5253 // This is a real section group, and we've already seen a
5254 // linkonce section with this signature. Record that we've seen
5255 // a section group, and don't include this section group.
5256 ins.first->second.set_is_group_name();
5261 // We've already seen a linkonce section and this is a linkonce
5262 // section. These don't block each other--this may be the same
5263 // symbol name with different section types.
5268 // Store the allocated sections into the section list.
5271 Layout::get_allocated_sections(Section_list* section_list) const
5273 for (Section_list::const_iterator p = this->section_list_.begin();
5274 p != this->section_list_.end();
5276 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
5277 section_list->push_back(*p);
5280 // Store the executable sections into the section list.
5283 Layout::get_executable_sections(Section_list* section_list) const
5285 for (Section_list::const_iterator p = this->section_list_.begin();
5286 p != this->section_list_.end();
5288 if (((*p)->flags() & (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR))
5289 == (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR))
5290 section_list->push_back(*p);
5293 // Create an output segment.
5296 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
5298 gold_assert(!parameters->options().relocatable());
5299 Output_segment* oseg = new Output_segment(type, flags);
5300 this->segment_list_.push_back(oseg);
5302 if (type == elfcpp::PT_TLS)
5303 this->tls_segment_ = oseg;
5304 else if (type == elfcpp::PT_GNU_RELRO)
5305 this->relro_segment_ = oseg;
5306 else if (type == elfcpp::PT_INTERP)
5307 this->interp_segment_ = oseg;
5312 // Return the file offset of the normal symbol table.
5315 Layout::symtab_section_offset() const
5317 if (this->symtab_section_ != NULL)
5318 return this->symtab_section_->offset();
5322 // Return the section index of the normal symbol table. It may have
5323 // been stripped by the -s/--strip-all option.
5326 Layout::symtab_section_shndx() const
5328 if (this->symtab_section_ != NULL)
5329 return this->symtab_section_->out_shndx();
5333 // Write out the Output_sections. Most won't have anything to write,
5334 // since most of the data will come from input sections which are
5335 // handled elsewhere. But some Output_sections do have Output_data.
5338 Layout::write_output_sections(Output_file* of) const
5340 for (Section_list::const_iterator p = this->section_list_.begin();
5341 p != this->section_list_.end();
5344 if (!(*p)->after_input_sections())
5349 // Write out data not associated with a section or the symbol table.
5352 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
5354 if (!parameters->options().strip_all())
5356 const Output_section* symtab_section = this->symtab_section_;
5357 for (Section_list::const_iterator p = this->section_list_.begin();
5358 p != this->section_list_.end();
5361 if ((*p)->needs_symtab_index())
5363 gold_assert(symtab_section != NULL);
5364 unsigned int index = (*p)->symtab_index();
5365 gold_assert(index > 0 && index != -1U);
5366 off_t off = (symtab_section->offset()
5367 + index * symtab_section->entsize());
5368 symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
5373 const Output_section* dynsym_section = this->dynsym_section_;
5374 for (Section_list::const_iterator p = this->section_list_.begin();
5375 p != this->section_list_.end();
5378 if ((*p)->needs_dynsym_index())
5380 gold_assert(dynsym_section != NULL);
5381 unsigned int index = (*p)->dynsym_index();
5382 gold_assert(index > 0 && index != -1U);
5383 off_t off = (dynsym_section->offset()
5384 + index * dynsym_section->entsize());
5385 symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
5389 // Write out the Output_data which are not in an Output_section.
5390 for (Data_list::const_iterator p = this->special_output_list_.begin();
5391 p != this->special_output_list_.end();
5395 // Write out the Output_data which are not in an Output_section
5396 // and are regenerated in each iteration of relaxation.
5397 for (Data_list::const_iterator p = this->relax_output_list_.begin();
5398 p != this->relax_output_list_.end();
5403 // Write out the Output_sections which can only be written after the
5404 // input sections are complete.
5407 Layout::write_sections_after_input_sections(Output_file* of)
5409 // Determine the final section offsets, and thus the final output
5410 // file size. Note we finalize the .shstrab last, to allow the
5411 // after_input_section sections to modify their section-names before
5413 if (this->any_postprocessing_sections_)
5415 off_t off = this->output_file_size_;
5416 off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
5418 // Now that we've finalized the names, we can finalize the shstrab.
5420 this->set_section_offsets(off,
5421 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
5423 if (off > this->output_file_size_)
5426 this->output_file_size_ = off;
5430 for (Section_list::const_iterator p = this->section_list_.begin();
5431 p != this->section_list_.end();
5434 if ((*p)->after_input_sections())
5438 this->section_headers_->write(of);
5441 // If a tree-style build ID was requested, the parallel part of that computation
5442 // is already done, and the final hash-of-hashes is computed here. For other
5443 // types of build IDs, all the work is done here.
5446 Layout::write_build_id(Output_file* of, unsigned char* array_of_hashes,
5447 size_t size_of_hashes) const
5449 if (this->build_id_note_ == NULL)
5452 unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
5453 this->build_id_note_->data_size());
5455 if (array_of_hashes == NULL)
5457 const size_t output_file_size = this->output_file_size();
5458 const unsigned char* iv = of->get_input_view(0, output_file_size);
5459 const char* style = parameters->options().build_id();
5461 // If we get here with style == "tree" then the output must be
5462 // too small for chunking, and we use SHA-1 in that case.
5463 if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0))
5464 sha1_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov);
5465 else if (strcmp(style, "md5") == 0)
5466 md5_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov);
5470 of->free_input_view(0, output_file_size, iv);
5474 // Non-overlapping substrings of the output file have been hashed.
5475 // Compute SHA-1 hash of the hashes.
5476 sha1_buffer(reinterpret_cast<const char*>(array_of_hashes),
5477 size_of_hashes, ov);
5478 delete[] array_of_hashes;
5481 of->write_output_view(this->build_id_note_->offset(),
5482 this->build_id_note_->data_size(),
5486 // Write out a binary file. This is called after the link is
5487 // complete. IN is the temporary output file we used to generate the
5488 // ELF code. We simply walk through the segments, read them from
5489 // their file offset in IN, and write them to their load address in
5490 // the output file. FIXME: with a bit more work, we could support
5491 // S-records and/or Intel hex format here.
5494 Layout::write_binary(Output_file* in) const
5496 gold_assert(parameters->options().oformat_enum()
5497 == General_options::OBJECT_FORMAT_BINARY);
5499 // Get the size of the binary file.
5500 uint64_t max_load_address = 0;
5501 for (Segment_list::const_iterator p = this->segment_list_.begin();
5502 p != this->segment_list_.end();
5505 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
5507 uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
5508 if (max_paddr > max_load_address)
5509 max_load_address = max_paddr;
5513 Output_file out(parameters->options().output_file_name());
5514 out.open(max_load_address);
5516 for (Segment_list::const_iterator p = this->segment_list_.begin();
5517 p != this->segment_list_.end();
5520 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
5522 const unsigned char* vin = in->get_input_view((*p)->offset(),
5524 unsigned char* vout = out.get_output_view((*p)->paddr(),
5526 memcpy(vout, vin, (*p)->filesz());
5527 out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
5528 in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
5535 // Print the output sections to the map file.
5538 Layout::print_to_mapfile(Mapfile* mapfile) const
5540 for (Segment_list::const_iterator p = this->segment_list_.begin();
5541 p != this->segment_list_.end();
5543 (*p)->print_sections_to_mapfile(mapfile);
5544 for (Section_list::const_iterator p = this->unattached_section_list_.begin();
5545 p != this->unattached_section_list_.end();
5547 (*p)->print_to_mapfile(mapfile);
5550 // Print statistical information to stderr. This is used for --stats.
5553 Layout::print_stats() const
5555 this->namepool_.print_stats("section name pool");
5556 this->sympool_.print_stats("output symbol name pool");
5557 this->dynpool_.print_stats("dynamic name pool");
5559 for (Section_list::const_iterator p = this->section_list_.begin();
5560 p != this->section_list_.end();
5562 (*p)->print_merge_stats();
5565 // Write_sections_task methods.
5567 // We can always run this task.
5570 Write_sections_task::is_runnable()
5575 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5579 Write_sections_task::locks(Task_locker* tl)
5581 tl->add(this, this->output_sections_blocker_);
5582 if (this->input_sections_blocker_ != NULL)
5583 tl->add(this, this->input_sections_blocker_);
5584 tl->add(this, this->final_blocker_);
5587 // Run the task--write out the data.
5590 Write_sections_task::run(Workqueue*)
5592 this->layout_->write_output_sections(this->of_);
5595 // Write_data_task methods.
5597 // We can always run this task.
5600 Write_data_task::is_runnable()
5605 // We need to unlock FINAL_BLOCKER when finished.
5608 Write_data_task::locks(Task_locker* tl)
5610 tl->add(this, this->final_blocker_);
5613 // Run the task--write out the data.
5616 Write_data_task::run(Workqueue*)
5618 this->layout_->write_data(this->symtab_, this->of_);
5621 // Write_symbols_task methods.
5623 // We can always run this task.
5626 Write_symbols_task::is_runnable()
5631 // We need to unlock FINAL_BLOCKER when finished.
5634 Write_symbols_task::locks(Task_locker* tl)
5636 tl->add(this, this->final_blocker_);
5639 // Run the task--write out the symbols.
5642 Write_symbols_task::run(Workqueue*)
5644 this->symtab_->write_globals(this->sympool_, this->dynpool_,
5645 this->layout_->symtab_xindex(),
5646 this->layout_->dynsym_xindex(), this->of_);
5649 // Write_after_input_sections_task methods.
5651 // We can only run this task after the input sections have completed.
5654 Write_after_input_sections_task::is_runnable()
5656 if (this->input_sections_blocker_->is_blocked())
5657 return this->input_sections_blocker_;
5661 // We need to unlock FINAL_BLOCKER when finished.
5664 Write_after_input_sections_task::locks(Task_locker* tl)
5666 tl->add(this, this->final_blocker_);
5672 Write_after_input_sections_task::run(Workqueue*)
5674 this->layout_->write_sections_after_input_sections(this->of_);
5677 // Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes,
5678 // or as a "tree" where each chunk of the string is hashed and then those
5679 // hashes are put into a (much smaller) string which is hashed with sha1.
5680 // We compute a checksum over the entire file because that is simplest.
5683 Build_id_task_runner::run(Workqueue* workqueue, const Task*)
5685 Task_token* post_hash_tasks_blocker = new Task_token(true);
5686 const Layout* layout = this->layout_;
5687 Output_file* of = this->of_;
5688 const size_t filesize = (layout->output_file_size() <= 0 ? 0
5689 : static_cast<size_t>(layout->output_file_size()));
5690 unsigned char* array_of_hashes = NULL;
5691 size_t size_of_hashes = 0;
5693 if (strcmp(this->options_->build_id(), "tree") == 0
5694 && this->options_->build_id_chunk_size_for_treehash() > 0
5696 && (filesize >= this->options_->build_id_min_file_size_for_treehash()))
5698 static const size_t MD5_OUTPUT_SIZE_IN_BYTES = 16;
5699 const size_t chunk_size =
5700 this->options_->build_id_chunk_size_for_treehash();
5701 const size_t num_hashes = ((filesize - 1) / chunk_size) + 1;
5702 post_hash_tasks_blocker->add_blockers(num_hashes);
5703 size_of_hashes = num_hashes * MD5_OUTPUT_SIZE_IN_BYTES;
5704 array_of_hashes = new unsigned char[size_of_hashes];
5705 unsigned char *dst = array_of_hashes;
5706 for (size_t i = 0, src_offset = 0; i < num_hashes;
5707 i++, dst += MD5_OUTPUT_SIZE_IN_BYTES, src_offset += chunk_size)
5709 size_t size = std::min(chunk_size, filesize - src_offset);
5710 workqueue->queue(new Hash_task(of,
5714 post_hash_tasks_blocker));
5718 // Queue the final task to write the build id and close the output file.
5719 workqueue->queue(new Task_function(new Close_task_runner(this->options_,
5724 post_hash_tasks_blocker,
5725 "Task_function Close_task_runner"));
5728 // Close_task_runner methods.
5730 // Finish up the build ID computation, if necessary, and write a binary file,
5731 // if necessary. Then close the output file.
5734 Close_task_runner::run(Workqueue*, const Task*)
5736 // At this point the multi-threaded part of the build ID computation,
5737 // if any, is done. See Build_id_task_runner.
5738 this->layout_->write_build_id(this->of_, this->array_of_hashes_,
5739 this->size_of_hashes_);
5741 // If we've been asked to create a binary file, we do so here.
5742 if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
5743 this->layout_->write_binary(this->of_);
5748 // Instantiate the templates we need. We could use the configure
5749 // script to restrict this to only the ones for implemented targets.
5751 #ifdef HAVE_TARGET_32_LITTLE
5754 Layout::init_fixed_output_section<32, false>(
5756 elfcpp::Shdr<32, false>& shdr);
5759 #ifdef HAVE_TARGET_32_BIG
5762 Layout::init_fixed_output_section<32, true>(
5764 elfcpp::Shdr<32, true>& shdr);
5767 #ifdef HAVE_TARGET_64_LITTLE
5770 Layout::init_fixed_output_section<64, false>(
5772 elfcpp::Shdr<64, false>& shdr);
5775 #ifdef HAVE_TARGET_64_BIG
5778 Layout::init_fixed_output_section<64, true>(
5780 elfcpp::Shdr<64, true>& shdr);
5783 #ifdef HAVE_TARGET_32_LITTLE
5786 Layout::layout<32, false>(Sized_relobj_file<32, false>* object,
5789 const elfcpp::Shdr<32, false>& shdr,
5790 unsigned int, unsigned int, off_t*);
5793 #ifdef HAVE_TARGET_32_BIG
5796 Layout::layout<32, true>(Sized_relobj_file<32, true>* object,
5799 const elfcpp::Shdr<32, true>& shdr,
5800 unsigned int, unsigned int, off_t*);
5803 #ifdef HAVE_TARGET_64_LITTLE
5806 Layout::layout<64, false>(Sized_relobj_file<64, false>* object,
5809 const elfcpp::Shdr<64, false>& shdr,
5810 unsigned int, unsigned int, off_t*);
5813 #ifdef HAVE_TARGET_64_BIG
5816 Layout::layout<64, true>(Sized_relobj_file<64, true>* object,
5819 const elfcpp::Shdr<64, true>& shdr,
5820 unsigned int, unsigned int, off_t*);
5823 #ifdef HAVE_TARGET_32_LITTLE
5826 Layout::layout_reloc<32, false>(Sized_relobj_file<32, false>* object,
5827 unsigned int reloc_shndx,
5828 const elfcpp::Shdr<32, false>& shdr,
5829 Output_section* data_section,
5830 Relocatable_relocs* rr);
5833 #ifdef HAVE_TARGET_32_BIG
5836 Layout::layout_reloc<32, true>(Sized_relobj_file<32, true>* object,
5837 unsigned int reloc_shndx,
5838 const elfcpp::Shdr<32, true>& shdr,
5839 Output_section* data_section,
5840 Relocatable_relocs* rr);
5843 #ifdef HAVE_TARGET_64_LITTLE
5846 Layout::layout_reloc<64, false>(Sized_relobj_file<64, false>* object,
5847 unsigned int reloc_shndx,
5848 const elfcpp::Shdr<64, false>& shdr,
5849 Output_section* data_section,
5850 Relocatable_relocs* rr);
5853 #ifdef HAVE_TARGET_64_BIG
5856 Layout::layout_reloc<64, true>(Sized_relobj_file<64, true>* object,
5857 unsigned int reloc_shndx,
5858 const elfcpp::Shdr<64, true>& shdr,
5859 Output_section* data_section,
5860 Relocatable_relocs* rr);
5863 #ifdef HAVE_TARGET_32_LITTLE
5866 Layout::layout_group<32, false>(Symbol_table* symtab,
5867 Sized_relobj_file<32, false>* object,
5869 const char* group_section_name,
5870 const char* signature,
5871 const elfcpp::Shdr<32, false>& shdr,
5872 elfcpp::Elf_Word flags,
5873 std::vector<unsigned int>* shndxes);
5876 #ifdef HAVE_TARGET_32_BIG
5879 Layout::layout_group<32, true>(Symbol_table* symtab,
5880 Sized_relobj_file<32, true>* object,
5882 const char* group_section_name,
5883 const char* signature,
5884 const elfcpp::Shdr<32, true>& shdr,
5885 elfcpp::Elf_Word flags,
5886 std::vector<unsigned int>* shndxes);
5889 #ifdef HAVE_TARGET_64_LITTLE
5892 Layout::layout_group<64, false>(Symbol_table* symtab,
5893 Sized_relobj_file<64, false>* object,
5895 const char* group_section_name,
5896 const char* signature,
5897 const elfcpp::Shdr<64, false>& shdr,
5898 elfcpp::Elf_Word flags,
5899 std::vector<unsigned int>* shndxes);
5902 #ifdef HAVE_TARGET_64_BIG
5905 Layout::layout_group<64, true>(Symbol_table* symtab,
5906 Sized_relobj_file<64, true>* object,
5908 const char* group_section_name,
5909 const char* signature,
5910 const elfcpp::Shdr<64, true>& shdr,
5911 elfcpp::Elf_Word flags,
5912 std::vector<unsigned int>* shndxes);
5915 #ifdef HAVE_TARGET_32_LITTLE
5918 Layout::layout_eh_frame<32, false>(Sized_relobj_file<32, false>* object,
5919 const unsigned char* symbols,
5921 const unsigned char* symbol_names,
5922 off_t symbol_names_size,
5924 const elfcpp::Shdr<32, false>& shdr,
5925 unsigned int reloc_shndx,
5926 unsigned int reloc_type,
5930 #ifdef HAVE_TARGET_32_BIG
5933 Layout::layout_eh_frame<32, true>(Sized_relobj_file<32, true>* object,
5934 const unsigned char* symbols,
5936 const unsigned char* symbol_names,
5937 off_t symbol_names_size,
5939 const elfcpp::Shdr<32, true>& shdr,
5940 unsigned int reloc_shndx,
5941 unsigned int reloc_type,
5945 #ifdef HAVE_TARGET_64_LITTLE
5948 Layout::layout_eh_frame<64, false>(Sized_relobj_file<64, false>* object,
5949 const unsigned char* symbols,
5951 const unsigned char* symbol_names,
5952 off_t symbol_names_size,
5954 const elfcpp::Shdr<64, false>& shdr,
5955 unsigned int reloc_shndx,
5956 unsigned int reloc_type,
5960 #ifdef HAVE_TARGET_64_BIG
5963 Layout::layout_eh_frame<64, true>(Sized_relobj_file<64, true>* object,
5964 const unsigned char* symbols,
5966 const unsigned char* symbol_names,
5967 off_t symbol_names_size,
5969 const elfcpp::Shdr<64, true>& shdr,
5970 unsigned int reloc_shndx,
5971 unsigned int reloc_type,
5975 #ifdef HAVE_TARGET_32_LITTLE
5978 Layout::add_to_gdb_index(bool is_type_unit,
5979 Sized_relobj<32, false>* object,
5980 const unsigned char* symbols,
5983 unsigned int reloc_shndx,
5984 unsigned int reloc_type);
5987 #ifdef HAVE_TARGET_32_BIG
5990 Layout::add_to_gdb_index(bool is_type_unit,
5991 Sized_relobj<32, true>* object,
5992 const unsigned char* symbols,
5995 unsigned int reloc_shndx,
5996 unsigned int reloc_type);
5999 #ifdef HAVE_TARGET_64_LITTLE
6002 Layout::add_to_gdb_index(bool is_type_unit,
6003 Sized_relobj<64, false>* object,
6004 const unsigned char* symbols,
6007 unsigned int reloc_shndx,
6008 unsigned int reloc_type);
6011 #ifdef HAVE_TARGET_64_BIG
6014 Layout::add_to_gdb_index(bool is_type_unit,
6015 Sized_relobj<64, true>* object,
6016 const unsigned char* symbols,
6019 unsigned int reloc_shndx,
6020 unsigned int reloc_type);
6023 } // End namespace gold.