1 // layout.cc -- lay out output file sections for gold
3 // Copyright (C) 2006-2015 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
34 #include "libiberty.h"
38 #include "parameters.h"
42 #include "script-sections.h"
47 #include "gdb-index.h"
48 #include "compressed_output.h"
49 #include "reduced_debug_output.h"
52 #include "descriptors.h"
54 #include "incremental.h"
62 // The total number of free lists used.
63 unsigned int Free_list::num_lists = 0;
64 // The total number of free list nodes used.
65 unsigned int Free_list::num_nodes = 0;
66 // The total number of calls to Free_list::remove.
67 unsigned int Free_list::num_removes = 0;
68 // The total number of nodes visited during calls to Free_list::remove.
69 unsigned int Free_list::num_remove_visits = 0;
70 // The total number of calls to Free_list::allocate.
71 unsigned int Free_list::num_allocates = 0;
72 // The total number of nodes visited during calls to Free_list::allocate.
73 unsigned int Free_list::num_allocate_visits = 0;
75 // Initialize the free list. Creates a single free list node that
76 // describes the entire region of length LEN. If EXTEND is true,
77 // allocate() is allowed to extend the region beyond its initial
81 Free_list::init(off_t len, bool extend)
83 this->list_.push_front(Free_list_node(0, len));
84 this->last_remove_ = this->list_.begin();
85 this->extend_ = extend;
87 ++Free_list::num_lists;
88 ++Free_list::num_nodes;
91 // Remove a chunk from the free list. Because we start with a single
92 // node that covers the entire section, and remove chunks from it one
93 // at a time, we do not need to coalesce chunks or handle cases that
94 // span more than one free node. We expect to remove chunks from the
95 // free list in order, and we expect to have only a few chunks of free
96 // space left (corresponding to files that have changed since the last
97 // incremental link), so a simple linear list should provide sufficient
101 Free_list::remove(off_t start, off_t end)
105 gold_assert(start < end);
107 ++Free_list::num_removes;
109 Iterator p = this->last_remove_;
110 if (p->start_ > start)
111 p = this->list_.begin();
113 for (; p != this->list_.end(); ++p)
115 ++Free_list::num_remove_visits;
116 // Find a node that wholly contains the indicated region.
117 if (p->start_ <= start && p->end_ >= end)
119 // Case 1: the indicated region spans the whole node.
120 // Add some fuzz to avoid creating tiny free chunks.
121 if (p->start_ + 3 >= start && p->end_ <= end + 3)
122 p = this->list_.erase(p);
123 // Case 2: remove a chunk from the start of the node.
124 else if (p->start_ + 3 >= start)
126 // Case 3: remove a chunk from the end of the node.
127 else if (p->end_ <= end + 3)
129 // Case 4: remove a chunk from the middle, and split
130 // the node into two.
133 Free_list_node newnode(p->start_, start);
135 this->list_.insert(p, newnode);
136 ++Free_list::num_nodes;
138 this->last_remove_ = p;
143 // Did not find a node containing the given chunk. This could happen
144 // because a small chunk was already removed due to the fuzz.
145 gold_debug(DEBUG_INCREMENTAL,
146 "Free_list::remove(%d,%d) not found",
147 static_cast<int>(start), static_cast<int>(end));
150 // Allocate a chunk of size LEN from the free list. Returns -1ULL
151 // if a sufficiently large chunk of free space is not found.
152 // We use a simple first-fit algorithm.
155 Free_list::allocate(off_t len, uint64_t align, off_t minoff)
157 gold_debug(DEBUG_INCREMENTAL,
158 "Free_list::allocate(%08lx, %d, %08lx)",
159 static_cast<long>(len), static_cast<int>(align),
160 static_cast<long>(minoff));
162 return align_address(minoff, align);
164 ++Free_list::num_allocates;
166 // We usually want to drop free chunks smaller than 4 bytes.
167 // If we need to guarantee a minimum hole size, though, we need
168 // to keep track of all free chunks.
169 const int fuzz = this->min_hole_ > 0 ? 0 : 3;
171 for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
173 ++Free_list::num_allocate_visits;
174 off_t start = p->start_ > minoff ? p->start_ : minoff;
175 start = align_address(start, align);
176 off_t end = start + len;
177 if (end > p->end_ && p->end_ == this->length_ && this->extend_)
182 if (end == p->end_ || (end <= p->end_ - this->min_hole_))
184 if (p->start_ + fuzz >= start && p->end_ <= end + fuzz)
185 this->list_.erase(p);
186 else if (p->start_ + fuzz >= start)
188 else if (p->end_ <= end + fuzz)
192 Free_list_node newnode(p->start_, start);
194 this->list_.insert(p, newnode);
195 ++Free_list::num_nodes;
202 off_t start = align_address(this->length_, align);
203 this->length_ = start + len;
209 // Dump the free list (for debugging).
213 gold_info("Free list:\n start end length\n");
214 for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
215 gold_info(" %08lx %08lx %08lx", static_cast<long>(p->start_),
216 static_cast<long>(p->end_),
217 static_cast<long>(p->end_ - p->start_));
220 // Print the statistics for the free lists.
222 Free_list::print_stats()
224 fprintf(stderr, _("%s: total free lists: %u\n"),
225 program_name, Free_list::num_lists);
226 fprintf(stderr, _("%s: total free list nodes: %u\n"),
227 program_name, Free_list::num_nodes);
228 fprintf(stderr, _("%s: calls to Free_list::remove: %u\n"),
229 program_name, Free_list::num_removes);
230 fprintf(stderr, _("%s: nodes visited: %u\n"),
231 program_name, Free_list::num_remove_visits);
232 fprintf(stderr, _("%s: calls to Free_list::allocate: %u\n"),
233 program_name, Free_list::num_allocates);
234 fprintf(stderr, _("%s: nodes visited: %u\n"),
235 program_name, Free_list::num_allocate_visits);
238 // A Hash_task computes the MD5 checksum of an array of char.
240 class Hash_task : public Task
243 Hash_task(Output_file* of,
247 Task_token* final_blocker)
248 : of_(of), offset_(offset), size_(size), dst_(dst),
249 final_blocker_(final_blocker)
255 const unsigned char* iv =
256 this->of_->get_input_view(this->offset_, this->size_);
257 md5_buffer(reinterpret_cast<const char*>(iv), this->size_, this->dst_);
258 this->of_->free_input_view(this->offset_, this->size_, iv);
265 // Unblock FINAL_BLOCKER_ when done.
267 locks(Task_locker* tl)
268 { tl->add(this, this->final_blocker_); }
272 { return "Hash_task"; }
276 const size_t offset_;
278 unsigned char* const dst_;
279 Task_token* const final_blocker_;
282 // Layout::Relaxation_debug_check methods.
284 // Check that sections and special data are in reset states.
285 // We do not save states for Output_sections and special Output_data.
286 // So we check that they have not assigned any addresses or offsets.
287 // clean_up_after_relaxation simply resets their addresses and offsets.
289 Layout::Relaxation_debug_check::check_output_data_for_reset_values(
290 const Layout::Section_list& sections,
291 const Layout::Data_list& special_outputs,
292 const Layout::Data_list& relax_outputs)
294 for(Layout::Section_list::const_iterator p = sections.begin();
297 gold_assert((*p)->address_and_file_offset_have_reset_values());
299 for(Layout::Data_list::const_iterator p = special_outputs.begin();
300 p != special_outputs.end();
302 gold_assert((*p)->address_and_file_offset_have_reset_values());
304 gold_assert(relax_outputs.empty());
307 // Save information of SECTIONS for checking later.
310 Layout::Relaxation_debug_check::read_sections(
311 const Layout::Section_list& sections)
313 for(Layout::Section_list::const_iterator p = sections.begin();
317 Output_section* os = *p;
319 info.output_section = os;
320 info.address = os->is_address_valid() ? os->address() : 0;
321 info.data_size = os->is_data_size_valid() ? os->data_size() : -1;
322 info.offset = os->is_offset_valid()? os->offset() : -1 ;
323 this->section_infos_.push_back(info);
327 // Verify SECTIONS using previously recorded information.
330 Layout::Relaxation_debug_check::verify_sections(
331 const Layout::Section_list& sections)
334 for(Layout::Section_list::const_iterator p = sections.begin();
338 Output_section* os = *p;
339 uint64_t address = os->is_address_valid() ? os->address() : 0;
340 off_t data_size = os->is_data_size_valid() ? os->data_size() : -1;
341 off_t offset = os->is_offset_valid()? os->offset() : -1 ;
343 if (i >= this->section_infos_.size())
345 gold_fatal("Section_info of %s missing.\n", os->name());
347 const Section_info& info = this->section_infos_[i];
348 if (os != info.output_section)
349 gold_fatal("Section order changed. Expecting %s but see %s\n",
350 info.output_section->name(), os->name());
351 if (address != info.address
352 || data_size != info.data_size
353 || offset != info.offset)
354 gold_fatal("Section %s changed.\n", os->name());
358 // Layout_task_runner methods.
360 // Lay out the sections. This is called after all the input objects
364 Layout_task_runner::run(Workqueue* workqueue, const Task* task)
366 // See if any of the input definitions violate the One Definition Rule.
367 // TODO: if this is too slow, do this as a task, rather than inline.
368 this->symtab_->detect_odr_violations(task, this->options_.output_file_name());
370 Layout* layout = this->layout_;
371 off_t file_size = layout->finalize(this->input_objects_,
376 // Now we know the final size of the output file and we know where
377 // each piece of information goes.
379 if (this->mapfile_ != NULL)
381 this->mapfile_->print_discarded_sections(this->input_objects_);
382 layout->print_to_mapfile(this->mapfile_);
386 if (layout->incremental_base() == NULL)
388 of = new Output_file(parameters->options().output_file_name());
389 if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
390 of->set_is_temporary();
395 of = layout->incremental_base()->output_file();
397 // Apply the incremental relocations for symbols whose values
398 // have changed. We do this before we resize the file and start
399 // writing anything else to it, so that we can read the old
400 // incremental information from the file before (possibly)
402 if (parameters->incremental_update())
403 layout->incremental_base()->apply_incremental_relocs(this->symtab_,
407 of->resize(file_size);
410 // Queue up the final set of tasks.
411 gold::queue_final_tasks(this->options_, this->input_objects_,
412 this->symtab_, layout, workqueue, of);
417 Layout::Layout(int number_of_input_files, Script_options* script_options)
418 : number_of_input_files_(number_of_input_files),
419 script_options_(script_options),
427 unattached_section_list_(),
428 special_output_list_(),
429 relax_output_list_(),
430 section_headers_(NULL),
432 relro_segment_(NULL),
433 interp_segment_(NULL),
435 symtab_section_(NULL),
436 symtab_xindex_(NULL),
437 dynsym_section_(NULL),
438 dynsym_xindex_(NULL),
439 dynamic_section_(NULL),
440 dynamic_symbol_(NULL),
442 eh_frame_section_(NULL),
443 eh_frame_data_(NULL),
444 added_eh_frame_data_(false),
445 eh_frame_hdr_section_(NULL),
446 gdb_index_data_(NULL),
447 build_id_note_(NULL),
451 output_file_size_(-1),
452 have_added_input_section_(false),
453 sections_are_attached_(false),
454 input_requires_executable_stack_(false),
455 input_with_gnu_stack_note_(false),
456 input_without_gnu_stack_note_(false),
457 has_static_tls_(false),
458 any_postprocessing_sections_(false),
459 resized_signatures_(false),
460 have_stabstr_section_(false),
461 section_ordering_specified_(false),
462 unique_segment_for_sections_specified_(false),
463 incremental_inputs_(NULL),
464 record_output_section_data_from_script_(false),
465 script_output_section_data_list_(),
466 segment_states_(NULL),
467 relaxation_debug_check_(NULL),
468 section_order_map_(),
469 section_segment_map_(),
470 input_section_position_(),
471 input_section_glob_(),
472 incremental_base_(NULL),
475 // Make space for more than enough segments for a typical file.
476 // This is just for efficiency--it's OK if we wind up needing more.
477 this->segment_list_.reserve(12);
479 // We expect two unattached Output_data objects: the file header and
480 // the segment headers.
481 this->special_output_list_.reserve(2);
483 // Initialize structure needed for an incremental build.
484 if (parameters->incremental())
485 this->incremental_inputs_ = new Incremental_inputs;
487 // The section name pool is worth optimizing in all cases, because
488 // it is small, but there are often overlaps due to .rel sections.
489 this->namepool_.set_optimize();
492 // For incremental links, record the base file to be modified.
495 Layout::set_incremental_base(Incremental_binary* base)
497 this->incremental_base_ = base;
498 this->free_list_.init(base->output_file()->filesize(), true);
501 // Hash a key we use to look up an output section mapping.
504 Layout::Hash_key::operator()(const Layout::Key& k) const
506 return k.first + k.second.first + k.second.second;
509 // These are the debug sections that are actually used by gdb.
510 // Currently, we've checked versions of gdb up to and including 7.4.
511 // We only check the part of the name that follows ".debug_" or
514 static const char* gdb_sections[] =
517 "addr", // Fission extension
518 // "aranges", // not used by gdb as of 7.4
527 // "pubnames", // not used by gdb as of 7.4
528 // "pubtypes", // not used by gdb as of 7.4
529 // "gnu_pubnames", // Fission extension
530 // "gnu_pubtypes", // Fission extension
536 // This is the minimum set of sections needed for line numbers.
538 static const char* lines_only_debug_sections[] =
541 // "addr", // Fission extension
542 // "aranges", // not used by gdb as of 7.4
551 // "pubnames", // not used by gdb as of 7.4
552 // "pubtypes", // not used by gdb as of 7.4
553 // "gnu_pubnames", // Fission extension
554 // "gnu_pubtypes", // Fission extension
557 "str_offsets", // Fission extension
560 // These sections are the DWARF fast-lookup tables, and are not needed
561 // when building a .gdb_index section.
563 static const char* gdb_fast_lookup_sections[] =
572 // Returns whether the given debug section is in the list of
573 // debug-sections-used-by-some-version-of-gdb. SUFFIX is the
574 // portion of the name following ".debug_" or ".zdebug_".
577 is_gdb_debug_section(const char* suffix)
579 // We can do this faster: binary search or a hashtable. But why bother?
580 for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
581 if (strcmp(suffix, gdb_sections[i]) == 0)
586 // Returns whether the given section is needed for lines-only debugging.
589 is_lines_only_debug_section(const char* suffix)
591 // We can do this faster: binary search or a hashtable. But why bother?
593 i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections);
595 if (strcmp(suffix, lines_only_debug_sections[i]) == 0)
600 // Returns whether the given section is a fast-lookup section that
601 // will not be needed when building a .gdb_index section.
604 is_gdb_fast_lookup_section(const char* suffix)
606 // We can do this faster: binary search or a hashtable. But why bother?
608 i < sizeof(gdb_fast_lookup_sections)/sizeof(*gdb_fast_lookup_sections);
610 if (strcmp(suffix, gdb_fast_lookup_sections[i]) == 0)
615 // Sometimes we compress sections. This is typically done for
616 // sections that are not part of normal program execution (such as
617 // .debug_* sections), and where the readers of these sections know
618 // how to deal with compressed sections. This routine doesn't say for
619 // certain whether we'll compress -- it depends on commandline options
620 // as well -- just whether this section is a candidate for compression.
621 // (The Output_compressed_section class decides whether to compress
622 // a given section, and picks the name of the compressed section.)
625 is_compressible_debug_section(const char* secname)
627 return (is_prefix_of(".debug", secname));
630 // We may see compressed debug sections in input files. Return TRUE
631 // if this is the name of a compressed debug section.
634 is_compressed_debug_section(const char* secname)
636 return (is_prefix_of(".zdebug", secname));
639 // Whether to include this section in the link.
641 template<int size, bool big_endian>
643 Layout::include_section(Sized_relobj_file<size, big_endian>*, const char* name,
644 const elfcpp::Shdr<size, big_endian>& shdr)
646 if (!parameters->options().relocatable()
647 && (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE))
650 elfcpp::Elf_Word sh_type = shdr.get_sh_type();
652 if ((sh_type >= elfcpp::SHT_LOOS && sh_type <= elfcpp::SHT_HIOS)
653 || (sh_type >= elfcpp::SHT_LOPROC && sh_type <= elfcpp::SHT_HIPROC))
654 return parameters->target().should_include_section(sh_type);
658 case elfcpp::SHT_NULL:
659 case elfcpp::SHT_SYMTAB:
660 case elfcpp::SHT_DYNSYM:
661 case elfcpp::SHT_HASH:
662 case elfcpp::SHT_DYNAMIC:
663 case elfcpp::SHT_SYMTAB_SHNDX:
666 case elfcpp::SHT_STRTAB:
667 // Discard the sections which have special meanings in the ELF
668 // ABI. Keep others (e.g., .stabstr). We could also do this by
669 // checking the sh_link fields of the appropriate sections.
670 return (strcmp(name, ".dynstr") != 0
671 && strcmp(name, ".strtab") != 0
672 && strcmp(name, ".shstrtab") != 0);
674 case elfcpp::SHT_RELA:
675 case elfcpp::SHT_REL:
676 case elfcpp::SHT_GROUP:
677 // If we are emitting relocations these should be handled
679 gold_assert(!parameters->options().relocatable());
682 case elfcpp::SHT_PROGBITS:
683 if (parameters->options().strip_debug()
684 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
686 if (is_debug_info_section(name))
689 if (parameters->options().strip_debug_non_line()
690 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
692 // Debugging sections can only be recognized by name.
693 if (is_prefix_of(".debug_", name)
694 && !is_lines_only_debug_section(name + 7))
696 if (is_prefix_of(".zdebug_", name)
697 && !is_lines_only_debug_section(name + 8))
700 if (parameters->options().strip_debug_gdb()
701 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
703 // Debugging sections can only be recognized by name.
704 if (is_prefix_of(".debug_", name)
705 && !is_gdb_debug_section(name + 7))
707 if (is_prefix_of(".zdebug_", name)
708 && !is_gdb_debug_section(name + 8))
711 if (parameters->options().gdb_index()
712 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
714 // When building .gdb_index, we can strip .debug_pubnames,
715 // .debug_pubtypes, and .debug_aranges sections.
716 if (is_prefix_of(".debug_", name)
717 && is_gdb_fast_lookup_section(name + 7))
719 if (is_prefix_of(".zdebug_", name)
720 && is_gdb_fast_lookup_section(name + 8))
723 if (parameters->options().strip_lto_sections()
724 && !parameters->options().relocatable()
725 && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
727 // Ignore LTO sections containing intermediate code.
728 if (is_prefix_of(".gnu.lto_", name))
731 // The GNU linker strips .gnu_debuglink sections, so we do too.
732 // This is a feature used to keep debugging information in
734 if (strcmp(name, ".gnu_debuglink") == 0)
743 // Return an output section named NAME, or NULL if there is none.
746 Layout::find_output_section(const char* name) const
748 for (Section_list::const_iterator p = this->section_list_.begin();
749 p != this->section_list_.end();
751 if (strcmp((*p)->name(), name) == 0)
756 // Return an output segment of type TYPE, with segment flags SET set
757 // and segment flags CLEAR clear. Return NULL if there is none.
760 Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
761 elfcpp::Elf_Word clear) const
763 for (Segment_list::const_iterator p = this->segment_list_.begin();
764 p != this->segment_list_.end();
766 if (static_cast<elfcpp::PT>((*p)->type()) == type
767 && ((*p)->flags() & set) == set
768 && ((*p)->flags() & clear) == 0)
773 // When we put a .ctors or .dtors section with more than one word into
774 // a .init_array or .fini_array section, we need to reverse the words
775 // in the .ctors/.dtors section. This is because .init_array executes
776 // constructors front to back, where .ctors executes them back to
777 // front, and vice-versa for .fini_array/.dtors. Although we do want
778 // to remap .ctors/.dtors into .init_array/.fini_array because it can
779 // be more efficient, we don't want to change the order in which
780 // constructors/destructors are run. This set just keeps track of
781 // these sections which need to be reversed. It is only changed by
782 // Layout::layout. It should be a private member of Layout, but that
783 // would require layout.h to #include object.h to get the definition
785 static Unordered_set<Section_id, Section_id_hash> ctors_sections_in_init_array;
787 // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a
788 // .init_array/.fini_array section.
791 Layout::is_ctors_in_init_array(Relobj* relobj, unsigned int shndx) const
793 return (ctors_sections_in_init_array.find(Section_id(relobj, shndx))
794 != ctors_sections_in_init_array.end());
797 // Return the output section to use for section NAME with type TYPE
798 // and section flags FLAGS. NAME must be canonicalized in the string
799 // pool, and NAME_KEY is the key. ORDER is where this should appear
800 // in the output sections. IS_RELRO is true for a relro section.
803 Layout::get_output_section(const char* name, Stringpool::Key name_key,
804 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
805 Output_section_order order, bool is_relro)
807 elfcpp::Elf_Word lookup_type = type;
809 // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and
810 // PREINIT_ARRAY like PROGBITS. This ensures that we combine
811 // .init_array, .fini_array, and .preinit_array sections by name
812 // whatever their type in the input file. We do this because the
813 // types are not always right in the input files.
814 if (lookup_type == elfcpp::SHT_INIT_ARRAY
815 || lookup_type == elfcpp::SHT_FINI_ARRAY
816 || lookup_type == elfcpp::SHT_PREINIT_ARRAY)
817 lookup_type = elfcpp::SHT_PROGBITS;
819 elfcpp::Elf_Xword lookup_flags = flags;
821 // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
822 // read-write with read-only sections. Some other ELF linkers do
823 // not do this. FIXME: Perhaps there should be an option
825 lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
827 const Key key(name_key, std::make_pair(lookup_type, lookup_flags));
828 const std::pair<Key, Output_section*> v(key, NULL);
829 std::pair<Section_name_map::iterator, bool> ins(
830 this->section_name_map_.insert(v));
833 return ins.first->second;
836 // This is the first time we've seen this name/type/flags
837 // combination. For compatibility with the GNU linker, we
838 // combine sections with contents and zero flags with sections
839 // with non-zero flags. This is a workaround for cases where
840 // assembler code forgets to set section flags. FIXME: Perhaps
841 // there should be an option to control this.
842 Output_section* os = NULL;
844 if (lookup_type == elfcpp::SHT_PROGBITS)
848 Output_section* same_name = this->find_output_section(name);
849 if (same_name != NULL
850 && (same_name->type() == elfcpp::SHT_PROGBITS
851 || same_name->type() == elfcpp::SHT_INIT_ARRAY
852 || same_name->type() == elfcpp::SHT_FINI_ARRAY
853 || same_name->type() == elfcpp::SHT_PREINIT_ARRAY)
854 && (same_name->flags() & elfcpp::SHF_TLS) == 0)
857 else if ((flags & elfcpp::SHF_TLS) == 0)
859 elfcpp::Elf_Xword zero_flags = 0;
860 const Key zero_key(name_key, std::make_pair(lookup_type,
862 Section_name_map::iterator p =
863 this->section_name_map_.find(zero_key);
864 if (p != this->section_name_map_.end())
870 os = this->make_output_section(name, type, flags, order, is_relro);
872 ins.first->second = os;
877 // Returns TRUE iff NAME (an input section from RELOBJ) will
878 // be mapped to an output section that should be KEPT.
881 Layout::keep_input_section(const Relobj* relobj, const char* name)
883 if (! this->script_options_->saw_sections_clause())
886 Script_sections* ss = this->script_options_->script_sections();
887 const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
888 Output_section** output_section_slot;
889 Script_sections::Section_type script_section_type;
892 name = ss->output_section_name(file_name, name, &output_section_slot,
893 &script_section_type, &keep);
894 return name != NULL && keep;
897 // Clear the input section flags that should not be copied to the
901 Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags)
903 // Some flags in the input section should not be automatically
904 // copied to the output section.
905 input_section_flags &= ~ (elfcpp::SHF_INFO_LINK
908 | elfcpp::SHF_STRINGS);
910 // We only clear the SHF_LINK_ORDER flag in for
911 // a non-relocatable link.
912 if (!parameters->options().relocatable())
913 input_section_flags &= ~elfcpp::SHF_LINK_ORDER;
915 return input_section_flags;
918 // Pick the output section to use for section NAME, in input file
919 // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
920 // linker created section. IS_INPUT_SECTION is true if we are
921 // choosing an output section for an input section found in a input
922 // file. ORDER is where this section should appear in the output
923 // sections. IS_RELRO is true for a relro section. This will return
924 // NULL if the input section should be discarded.
927 Layout::choose_output_section(const Relobj* relobj, const char* name,
928 elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
929 bool is_input_section, Output_section_order order,
932 // We should not see any input sections after we have attached
933 // sections to segments.
934 gold_assert(!is_input_section || !this->sections_are_attached_);
936 flags = this->get_output_section_flags(flags);
938 if (this->script_options_->saw_sections_clause())
940 // We are using a SECTIONS clause, so the output section is
941 // chosen based only on the name.
943 Script_sections* ss = this->script_options_->script_sections();
944 const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
945 Output_section** output_section_slot;
946 Script_sections::Section_type script_section_type;
947 const char* orig_name = name;
949 name = ss->output_section_name(file_name, name, &output_section_slot,
950 &script_section_type, &keep);
954 gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' "
955 "because it is not allowed by the "
956 "SECTIONS clause of the linker script"),
958 // The SECTIONS clause says to discard this input section.
962 // We can only handle script section types ST_NONE and ST_NOLOAD.
963 switch (script_section_type)
965 case Script_sections::ST_NONE:
967 case Script_sections::ST_NOLOAD:
968 flags &= elfcpp::SHF_ALLOC;
974 // If this is an orphan section--one not mentioned in the linker
975 // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
976 // default processing below.
978 if (output_section_slot != NULL)
980 if (*output_section_slot != NULL)
982 (*output_section_slot)->update_flags_for_input_section(flags);
983 return *output_section_slot;
986 // We don't put sections found in the linker script into
987 // SECTION_NAME_MAP_. That keeps us from getting confused
988 // if an orphan section is mapped to a section with the same
989 // name as one in the linker script.
991 name = this->namepool_.add(name, false, NULL);
993 Output_section* os = this->make_output_section(name, type, flags,
996 os->set_found_in_sections_clause();
998 // Special handling for NOLOAD sections.
999 if (script_section_type == Script_sections::ST_NOLOAD)
1001 os->set_is_noload();
1003 // The constructor of Output_section sets addresses of non-ALLOC
1004 // sections to 0 by default. We don't want that for NOLOAD
1005 // sections even if they have no SHF_ALLOC flag.
1006 if ((os->flags() & elfcpp::SHF_ALLOC) == 0
1007 && os->is_address_valid())
1009 gold_assert(os->address() == 0
1010 && !os->is_offset_valid()
1011 && !os->is_data_size_valid());
1012 os->reset_address_and_file_offset();
1016 *output_section_slot = os;
1021 // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
1023 size_t len = strlen(name);
1024 char* uncompressed_name = NULL;
1026 // Compressed debug sections should be mapped to the corresponding
1027 // uncompressed section.
1028 if (is_compressed_debug_section(name))
1030 uncompressed_name = new char[len];
1031 uncompressed_name[0] = '.';
1032 gold_assert(name[0] == '.' && name[1] == 'z');
1033 strncpy(&uncompressed_name[1], &name[2], len - 2);
1034 uncompressed_name[len - 1] = '\0';
1036 name = uncompressed_name;
1039 // Turn NAME from the name of the input section into the name of the
1041 if (is_input_section
1042 && !this->script_options_->saw_sections_clause()
1043 && !parameters->options().relocatable())
1045 const char *orig_name = name;
1046 name = parameters->target().output_section_name(relobj, name, &len);
1048 name = Layout::output_section_name(relobj, orig_name, &len);
1051 Stringpool::Key name_key;
1052 name = this->namepool_.add_with_length(name, len, true, &name_key);
1054 if (uncompressed_name != NULL)
1055 delete[] uncompressed_name;
1057 // Find or make the output section. The output section is selected
1058 // based on the section name, type, and flags.
1059 return this->get_output_section(name, name_key, type, flags, order, is_relro);
1062 // For incremental links, record the initial fixed layout of a section
1063 // from the base file, and return a pointer to the Output_section.
1065 template<int size, bool big_endian>
1067 Layout::init_fixed_output_section(const char* name,
1068 elfcpp::Shdr<size, big_endian>& shdr)
1070 unsigned int sh_type = shdr.get_sh_type();
1072 // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY,
1073 // PRE_INIT_ARRAY, and NOTE sections.
1074 // All others will be created from scratch and reallocated.
1075 if (!can_incremental_update(sh_type))
1078 // If we're generating a .gdb_index section, we need to regenerate
1080 if (parameters->options().gdb_index()
1081 && sh_type == elfcpp::SHT_PROGBITS
1082 && strcmp(name, ".gdb_index") == 0)
1085 typename elfcpp::Elf_types<size>::Elf_Addr sh_addr = shdr.get_sh_addr();
1086 typename elfcpp::Elf_types<size>::Elf_Off sh_offset = shdr.get_sh_offset();
1087 typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
1088 typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
1089 typename elfcpp::Elf_types<size>::Elf_WXword sh_addralign =
1090 shdr.get_sh_addralign();
1092 // Make the output section.
1093 Stringpool::Key name_key;
1094 name = this->namepool_.add(name, true, &name_key);
1095 Output_section* os = this->get_output_section(name, name_key, sh_type,
1096 sh_flags, ORDER_INVALID, false);
1097 os->set_fixed_layout(sh_addr, sh_offset, sh_size, sh_addralign);
1098 if (sh_type != elfcpp::SHT_NOBITS)
1099 this->free_list_.remove(sh_offset, sh_offset + sh_size);
1103 // Return the index by which an input section should be ordered. This
1104 // is used to sort some .text sections, for compatibility with GNU ld.
1107 Layout::special_ordering_of_input_section(const char* name)
1109 // The GNU linker has some special handling for some sections that
1110 // wind up in the .text section. Sections that start with these
1111 // prefixes must appear first, and must appear in the order listed
1113 static const char* const text_section_sort[] =
1122 i < sizeof(text_section_sort) / sizeof(text_section_sort[0]);
1124 if (is_prefix_of(text_section_sort[i], name))
1130 // Return the output section to use for input section SHNDX, with name
1131 // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
1132 // index of a relocation section which applies to this section, or 0
1133 // if none, or -1U if more than one. RELOC_TYPE is the type of the
1134 // relocation section if there is one. Set *OFF to the offset of this
1135 // input section without the output section. Return NULL if the
1136 // section should be discarded. Set *OFF to -1 if the section
1137 // contents should not be written directly to the output file, but
1138 // will instead receive special handling.
1140 template<int size, bool big_endian>
1142 Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx,
1143 const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
1144 unsigned int reloc_shndx, unsigned int, off_t* off)
1148 if (!this->include_section(object, name, shdr))
1151 elfcpp::Elf_Word sh_type = shdr.get_sh_type();
1153 // In a relocatable link a grouped section must not be combined with
1154 // any other sections.
1156 if (parameters->options().relocatable()
1157 && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
1159 name = this->namepool_.add(name, true, NULL);
1160 os = this->make_output_section(name, sh_type, shdr.get_sh_flags(),
1161 ORDER_INVALID, false);
1165 // Plugins can choose to place one or more subsets of sections in
1166 // unique segments and this is done by mapping these section subsets
1167 // to unique output sections. Check if this section needs to be
1168 // remapped to a unique output section.
1169 Section_segment_map::iterator it
1170 = this->section_segment_map_.find(Const_section_id(object, shndx));
1171 if (it == this->section_segment_map_.end())
1173 os = this->choose_output_section(object, name, sh_type,
1174 shdr.get_sh_flags(), true,
1175 ORDER_INVALID, false);
1179 // We know the name of the output section, directly call
1180 // get_output_section here by-passing choose_output_section.
1181 elfcpp::Elf_Xword flags
1182 = this->get_output_section_flags(shdr.get_sh_flags());
1184 const char* os_name = it->second->name;
1185 Stringpool::Key name_key;
1186 os_name = this->namepool_.add(os_name, true, &name_key);
1187 os = this->get_output_section(os_name, name_key, sh_type, flags,
1188 ORDER_INVALID, false);
1189 if (!os->is_unique_segment())
1191 os->set_is_unique_segment();
1192 os->set_extra_segment_flags(it->second->flags);
1193 os->set_segment_alignment(it->second->align);
1200 // By default the GNU linker sorts input sections whose names match
1201 // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The
1202 // sections are sorted by name. This is used to implement
1203 // constructor priority ordering. We are compatible. When we put
1204 // .ctor sections in .init_array and .dtor sections in .fini_array,
1205 // we must also sort plain .ctor and .dtor sections.
1206 if (!this->script_options_->saw_sections_clause()
1207 && !parameters->options().relocatable()
1208 && (is_prefix_of(".ctors.", name)
1209 || is_prefix_of(".dtors.", name)
1210 || is_prefix_of(".init_array.", name)
1211 || is_prefix_of(".fini_array.", name)
1212 || (parameters->options().ctors_in_init_array()
1213 && (strcmp(name, ".ctors") == 0
1214 || strcmp(name, ".dtors") == 0))))
1215 os->set_must_sort_attached_input_sections();
1217 // By default the GNU linker sorts some special text sections ahead
1218 // of others. We are compatible.
1219 if (parameters->options().text_reorder()
1220 && !this->script_options_->saw_sections_clause()
1221 && !this->is_section_ordering_specified()
1222 && !parameters->options().relocatable()
1223 && Layout::special_ordering_of_input_section(name) >= 0)
1224 os->set_must_sort_attached_input_sections();
1226 // If this is a .ctors or .ctors.* section being mapped to a
1227 // .init_array section, or a .dtors or .dtors.* section being mapped
1228 // to a .fini_array section, we will need to reverse the words if
1229 // there is more than one. Record this section for later. See
1230 // ctors_sections_in_init_array above.
1231 if (!this->script_options_->saw_sections_clause()
1232 && !parameters->options().relocatable()
1233 && shdr.get_sh_size() > size / 8
1234 && (((strcmp(name, ".ctors") == 0
1235 || is_prefix_of(".ctors.", name))
1236 && strcmp(os->name(), ".init_array") == 0)
1237 || ((strcmp(name, ".dtors") == 0
1238 || is_prefix_of(".dtors.", name))
1239 && strcmp(os->name(), ".fini_array") == 0)))
1240 ctors_sections_in_init_array.insert(Section_id(object, shndx));
1242 // FIXME: Handle SHF_LINK_ORDER somewhere.
1244 elfcpp::Elf_Xword orig_flags = os->flags();
1246 *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx,
1247 this->script_options_->saw_sections_clause());
1249 // If the flags changed, we may have to change the order.
1250 if ((orig_flags & elfcpp::SHF_ALLOC) != 0)
1252 orig_flags &= (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
1253 elfcpp::Elf_Xword new_flags =
1254 os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
1255 if (orig_flags != new_flags)
1256 os->set_order(this->default_section_order(os, false));
1259 this->have_added_input_section_ = true;
1264 // Maps section SECN to SEGMENT s.
1266 Layout::insert_section_segment_map(Const_section_id secn,
1267 Unique_segment_info *s)
1269 gold_assert(this->unique_segment_for_sections_specified_);
1270 this->section_segment_map_[secn] = s;
1273 // Handle a relocation section when doing a relocatable link.
1275 template<int size, bool big_endian>
1277 Layout::layout_reloc(Sized_relobj_file<size, big_endian>* object,
1279 const elfcpp::Shdr<size, big_endian>& shdr,
1280 Output_section* data_section,
1281 Relocatable_relocs* rr)
1283 gold_assert(parameters->options().relocatable()
1284 || parameters->options().emit_relocs());
1286 int sh_type = shdr.get_sh_type();
1289 if (sh_type == elfcpp::SHT_REL)
1291 else if (sh_type == elfcpp::SHT_RELA)
1295 name += data_section->name();
1297 // In a relocatable link relocs for a grouped section must not be
1298 // combined with other reloc sections.
1300 if (!parameters->options().relocatable()
1301 || (data_section->flags() & elfcpp::SHF_GROUP) == 0)
1302 os = this->choose_output_section(object, name.c_str(), sh_type,
1303 shdr.get_sh_flags(), false,
1304 ORDER_INVALID, false);
1307 const char* n = this->namepool_.add(name.c_str(), true, NULL);
1308 os = this->make_output_section(n, sh_type, shdr.get_sh_flags(),
1309 ORDER_INVALID, false);
1312 os->set_should_link_to_symtab();
1313 os->set_info_section(data_section);
1315 Output_section_data* posd;
1316 if (sh_type == elfcpp::SHT_REL)
1318 os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
1319 posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
1323 else if (sh_type == elfcpp::SHT_RELA)
1325 os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
1326 posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
1333 os->add_output_section_data(posd);
1334 rr->set_output_data(posd);
1339 // Handle a group section when doing a relocatable link.
1341 template<int size, bool big_endian>
1343 Layout::layout_group(Symbol_table* symtab,
1344 Sized_relobj_file<size, big_endian>* object,
1346 const char* group_section_name,
1347 const char* signature,
1348 const elfcpp::Shdr<size, big_endian>& shdr,
1349 elfcpp::Elf_Word flags,
1350 std::vector<unsigned int>* shndxes)
1352 gold_assert(parameters->options().relocatable());
1353 gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
1354 group_section_name = this->namepool_.add(group_section_name, true, NULL);
1355 Output_section* os = this->make_output_section(group_section_name,
1357 shdr.get_sh_flags(),
1358 ORDER_INVALID, false);
1360 // We need to find a symbol with the signature in the symbol table.
1361 // If we don't find one now, we need to look again later.
1362 Symbol* sym = symtab->lookup(signature, NULL);
1364 os->set_info_symndx(sym);
1367 // Reserve some space to minimize reallocations.
1368 if (this->group_signatures_.empty())
1369 this->group_signatures_.reserve(this->number_of_input_files_ * 16);
1371 // We will wind up using a symbol whose name is the signature.
1372 // So just put the signature in the symbol name pool to save it.
1373 signature = symtab->canonicalize_name(signature);
1374 this->group_signatures_.push_back(Group_signature(os, signature));
1377 os->set_should_link_to_symtab();
1380 section_size_type entry_count =
1381 convert_to_section_size_type(shdr.get_sh_size() / 4);
1382 Output_section_data* posd =
1383 new Output_data_group<size, big_endian>(object, entry_count, flags,
1385 os->add_output_section_data(posd);
1388 // Special GNU handling of sections name .eh_frame. They will
1389 // normally hold exception frame data as defined by the C++ ABI
1390 // (http://codesourcery.com/cxx-abi/).
1392 template<int size, bool big_endian>
1394 Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
1395 const unsigned char* symbols,
1397 const unsigned char* symbol_names,
1398 off_t symbol_names_size,
1400 const elfcpp::Shdr<size, big_endian>& shdr,
1401 unsigned int reloc_shndx, unsigned int reloc_type,
1404 gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS
1405 || shdr.get_sh_type() == elfcpp::SHT_X86_64_UNWIND);
1406 gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
1408 Output_section* os = this->make_eh_frame_section(object);
1412 gold_assert(this->eh_frame_section_ == os);
1414 elfcpp::Elf_Xword orig_flags = os->flags();
1416 Eh_frame::Eh_frame_section_disposition disp =
1417 Eh_frame::EH_UNRECOGNIZED_SECTION;
1418 if (!parameters->incremental())
1420 disp = this->eh_frame_data_->add_ehframe_input_section(object,
1430 if (disp == Eh_frame::EH_OPTIMIZABLE_SECTION)
1432 os->update_flags_for_input_section(shdr.get_sh_flags());
1434 // A writable .eh_frame section is a RELRO section.
1435 if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1436 != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1439 os->set_order(ORDER_RELRO);
1446 if (disp == Eh_frame::EH_END_MARKER_SECTION && !this->added_eh_frame_data_)
1448 // We found the end marker section, so now we can add the set of
1449 // optimized sections to the output section. We need to postpone
1450 // adding this until we've found a section we can optimize so that
1451 // the .eh_frame section in crtbeginT.o winds up at the start of
1452 // the output section.
1453 os->add_output_section_data(this->eh_frame_data_);
1454 this->added_eh_frame_data_ = true;
1457 // We couldn't handle this .eh_frame section for some reason.
1458 // Add it as a normal section.
1459 bool saw_sections_clause = this->script_options_->saw_sections_clause();
1460 *off = os->add_input_section(this, object, shndx, ".eh_frame", shdr,
1461 reloc_shndx, saw_sections_clause);
1462 this->have_added_input_section_ = true;
1464 if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
1465 != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
1466 os->set_order(this->default_section_order(os, false));
1472 Layout::finalize_eh_frame_section()
1474 // If we never found an end marker section, we need to add the
1475 // optimized eh sections to the output section now.
1476 if (!parameters->incremental()
1477 && this->eh_frame_section_ != NULL
1478 && !this->added_eh_frame_data_)
1480 this->eh_frame_section_->add_output_section_data(this->eh_frame_data_);
1481 this->added_eh_frame_data_ = true;
1485 // Create and return the magic .eh_frame section. Create
1486 // .eh_frame_hdr also if appropriate. OBJECT is the object with the
1487 // input .eh_frame section; it may be NULL.
1490 Layout::make_eh_frame_section(const Relobj* object)
1492 // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than
1494 Output_section* os = this->choose_output_section(object, ".eh_frame",
1495 elfcpp::SHT_PROGBITS,
1496 elfcpp::SHF_ALLOC, false,
1497 ORDER_EHFRAME, false);
1501 if (this->eh_frame_section_ == NULL)
1503 this->eh_frame_section_ = os;
1504 this->eh_frame_data_ = new Eh_frame();
1506 // For incremental linking, we do not optimize .eh_frame sections
1507 // or create a .eh_frame_hdr section.
1508 if (parameters->options().eh_frame_hdr() && !parameters->incremental())
1510 Output_section* hdr_os =
1511 this->choose_output_section(NULL, ".eh_frame_hdr",
1512 elfcpp::SHT_PROGBITS,
1513 elfcpp::SHF_ALLOC, false,
1514 ORDER_EHFRAME, false);
1518 Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
1519 this->eh_frame_data_);
1520 hdr_os->add_output_section_data(hdr_posd);
1522 hdr_os->set_after_input_sections();
1524 if (!this->script_options_->saw_phdrs_clause())
1526 Output_segment* hdr_oseg;
1527 hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
1529 hdr_oseg->add_output_section_to_nonload(hdr_os,
1533 this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
1541 // Add an exception frame for a PLT. This is called from target code.
1544 Layout::add_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data,
1545 size_t cie_length, const unsigned char* fde_data,
1548 if (parameters->incremental())
1550 // FIXME: Maybe this could work some day....
1553 Output_section* os = this->make_eh_frame_section(NULL);
1556 this->eh_frame_data_->add_ehframe_for_plt(plt, cie_data, cie_length,
1557 fde_data, fde_length);
1558 if (!this->added_eh_frame_data_)
1560 os->add_output_section_data(this->eh_frame_data_);
1561 this->added_eh_frame_data_ = true;
1565 // Scan a .debug_info or .debug_types section, and add summary
1566 // information to the .gdb_index section.
1568 template<int size, bool big_endian>
1570 Layout::add_to_gdb_index(bool is_type_unit,
1571 Sized_relobj<size, big_endian>* object,
1572 const unsigned char* symbols,
1575 unsigned int reloc_shndx,
1576 unsigned int reloc_type)
1578 if (this->gdb_index_data_ == NULL)
1580 Output_section* os = this->choose_output_section(NULL, ".gdb_index",
1581 elfcpp::SHT_PROGBITS, 0,
1582 false, ORDER_INVALID,
1587 this->gdb_index_data_ = new Gdb_index(os);
1588 os->add_output_section_data(this->gdb_index_data_);
1589 os->set_after_input_sections();
1592 this->gdb_index_data_->scan_debug_info(is_type_unit, object, symbols,
1593 symbols_size, shndx, reloc_shndx,
1597 // Add POSD to an output section using NAME, TYPE, and FLAGS. Return
1598 // the output section.
1601 Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
1602 elfcpp::Elf_Xword flags,
1603 Output_section_data* posd,
1604 Output_section_order order, bool is_relro)
1606 Output_section* os = this->choose_output_section(NULL, name, type, flags,
1607 false, order, is_relro);
1609 os->add_output_section_data(posd);
1613 // Map section flags to segment flags.
1616 Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
1618 elfcpp::Elf_Word ret = elfcpp::PF_R;
1619 if ((flags & elfcpp::SHF_WRITE) != 0)
1620 ret |= elfcpp::PF_W;
1621 if ((flags & elfcpp::SHF_EXECINSTR) != 0)
1622 ret |= elfcpp::PF_X;
1626 // Make a new Output_section, and attach it to segments as
1627 // appropriate. ORDER is the order in which this section should
1628 // appear in the output segment. IS_RELRO is true if this is a relro
1629 // (read-only after relocations) section.
1632 Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
1633 elfcpp::Elf_Xword flags,
1634 Output_section_order order, bool is_relro)
1637 if ((flags & elfcpp::SHF_ALLOC) == 0
1638 && strcmp(parameters->options().compress_debug_sections(), "none") != 0
1639 && is_compressible_debug_section(name))
1640 os = new Output_compressed_section(¶meters->options(), name, type,
1642 else if ((flags & elfcpp::SHF_ALLOC) == 0
1643 && parameters->options().strip_debug_non_line()
1644 && strcmp(".debug_abbrev", name) == 0)
1646 os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
1648 if (this->debug_info_)
1649 this->debug_info_->set_abbreviations(this->debug_abbrev_);
1651 else if ((flags & elfcpp::SHF_ALLOC) == 0
1652 && parameters->options().strip_debug_non_line()
1653 && strcmp(".debug_info", name) == 0)
1655 os = this->debug_info_ = new Output_reduced_debug_info_section(
1657 if (this->debug_abbrev_)
1658 this->debug_info_->set_abbreviations(this->debug_abbrev_);
1662 // Sometimes .init_array*, .preinit_array* and .fini_array* do
1663 // not have correct section types. Force them here.
1664 if (type == elfcpp::SHT_PROGBITS)
1666 if (is_prefix_of(".init_array", name))
1667 type = elfcpp::SHT_INIT_ARRAY;
1668 else if (is_prefix_of(".preinit_array", name))
1669 type = elfcpp::SHT_PREINIT_ARRAY;
1670 else if (is_prefix_of(".fini_array", name))
1671 type = elfcpp::SHT_FINI_ARRAY;
1674 // FIXME: const_cast is ugly.
1675 Target* target = const_cast<Target*>(¶meters->target());
1676 os = target->make_output_section(name, type, flags);
1679 // With -z relro, we have to recognize the special sections by name.
1680 // There is no other way.
1681 bool is_relro_local = false;
1682 if (!this->script_options_->saw_sections_clause()
1683 && parameters->options().relro()
1684 && (flags & elfcpp::SHF_ALLOC) != 0
1685 && (flags & elfcpp::SHF_WRITE) != 0)
1687 if (type == elfcpp::SHT_PROGBITS)
1689 if ((flags & elfcpp::SHF_TLS) != 0)
1691 else if (strcmp(name, ".data.rel.ro") == 0)
1693 else if (strcmp(name, ".data.rel.ro.local") == 0)
1696 is_relro_local = true;
1698 else if (strcmp(name, ".ctors") == 0
1699 || strcmp(name, ".dtors") == 0
1700 || strcmp(name, ".jcr") == 0)
1703 else if (type == elfcpp::SHT_INIT_ARRAY
1704 || type == elfcpp::SHT_FINI_ARRAY
1705 || type == elfcpp::SHT_PREINIT_ARRAY)
1712 if (order == ORDER_INVALID && (flags & elfcpp::SHF_ALLOC) != 0)
1713 order = this->default_section_order(os, is_relro_local);
1715 os->set_order(order);
1717 parameters->target().new_output_section(os);
1719 this->section_list_.push_back(os);
1721 // The GNU linker by default sorts some sections by priority, so we
1722 // do the same. We need to know that this might happen before we
1723 // attach any input sections.
1724 if (!this->script_options_->saw_sections_clause()
1725 && !parameters->options().relocatable()
1726 && (strcmp(name, ".init_array") == 0
1727 || strcmp(name, ".fini_array") == 0
1728 || (!parameters->options().ctors_in_init_array()
1729 && (strcmp(name, ".ctors") == 0
1730 || strcmp(name, ".dtors") == 0))))
1731 os->set_may_sort_attached_input_sections();
1733 // The GNU linker by default sorts .text.{unlikely,exit,startup,hot}
1734 // sections before other .text sections. We are compatible. We
1735 // need to know that this might happen before we attach any input
1737 if (parameters->options().text_reorder()
1738 && !this->script_options_->saw_sections_clause()
1739 && !this->is_section_ordering_specified()
1740 && !parameters->options().relocatable()
1741 && strcmp(name, ".text") == 0)
1742 os->set_may_sort_attached_input_sections();
1744 // GNU linker sorts section by name with --sort-section=name.
1745 if (strcmp(parameters->options().sort_section(), "name") == 0)
1746 os->set_must_sort_attached_input_sections();
1748 // Check for .stab*str sections, as .stab* sections need to link to
1750 if (type == elfcpp::SHT_STRTAB
1751 && !this->have_stabstr_section_
1752 && strncmp(name, ".stab", 5) == 0
1753 && strcmp(name + strlen(name) - 3, "str") == 0)
1754 this->have_stabstr_section_ = true;
1756 // During a full incremental link, we add patch space to most
1757 // PROGBITS and NOBITS sections. Flag those that may be
1758 // arbitrarily padded.
1759 if ((type == elfcpp::SHT_PROGBITS || type == elfcpp::SHT_NOBITS)
1760 && order != ORDER_INTERP
1761 && order != ORDER_INIT
1762 && order != ORDER_PLT
1763 && order != ORDER_FINI
1764 && order != ORDER_RELRO_LAST
1765 && order != ORDER_NON_RELRO_FIRST
1766 && strcmp(name, ".eh_frame") != 0
1767 && strcmp(name, ".ctors") != 0
1768 && strcmp(name, ".dtors") != 0
1769 && strcmp(name, ".jcr") != 0)
1771 os->set_is_patch_space_allowed();
1773 // Certain sections require "holes" to be filled with
1774 // specific fill patterns. These fill patterns may have
1775 // a minimum size, so we must prevent allocations from the
1776 // free list that leave a hole smaller than the minimum.
1777 if (strcmp(name, ".debug_info") == 0)
1778 os->set_free_space_fill(new Output_fill_debug_info(false));
1779 else if (strcmp(name, ".debug_types") == 0)
1780 os->set_free_space_fill(new Output_fill_debug_info(true));
1781 else if (strcmp(name, ".debug_line") == 0)
1782 os->set_free_space_fill(new Output_fill_debug_line());
1785 // If we have already attached the sections to segments, then we
1786 // need to attach this one now. This happens for sections created
1787 // directly by the linker.
1788 if (this->sections_are_attached_)
1789 this->attach_section_to_segment(¶meters->target(), os);
1794 // Return the default order in which a section should be placed in an
1795 // output segment. This function captures a lot of the ideas in
1796 // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a
1797 // linker created section is normally set when the section is created;
1798 // this function is used for input sections.
1800 Output_section_order
1801 Layout::default_section_order(Output_section* os, bool is_relro_local)
1803 gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0);
1804 bool is_write = (os->flags() & elfcpp::SHF_WRITE) != 0;
1805 bool is_execinstr = (os->flags() & elfcpp::SHF_EXECINSTR) != 0;
1806 bool is_bss = false;
1811 case elfcpp::SHT_PROGBITS:
1813 case elfcpp::SHT_NOBITS:
1816 case elfcpp::SHT_RELA:
1817 case elfcpp::SHT_REL:
1819 return ORDER_DYNAMIC_RELOCS;
1821 case elfcpp::SHT_HASH:
1822 case elfcpp::SHT_DYNAMIC:
1823 case elfcpp::SHT_SHLIB:
1824 case elfcpp::SHT_DYNSYM:
1825 case elfcpp::SHT_GNU_HASH:
1826 case elfcpp::SHT_GNU_verdef:
1827 case elfcpp::SHT_GNU_verneed:
1828 case elfcpp::SHT_GNU_versym:
1830 return ORDER_DYNAMIC_LINKER;
1832 case elfcpp::SHT_NOTE:
1833 return is_write ? ORDER_RW_NOTE : ORDER_RO_NOTE;
1836 if ((os->flags() & elfcpp::SHF_TLS) != 0)
1837 return is_bss ? ORDER_TLS_BSS : ORDER_TLS_DATA;
1839 if (!is_bss && !is_write)
1843 if (strcmp(os->name(), ".init") == 0)
1845 else if (strcmp(os->name(), ".fini") == 0)
1848 return is_execinstr ? ORDER_TEXT : ORDER_READONLY;
1852 return is_relro_local ? ORDER_RELRO_LOCAL : ORDER_RELRO;
1854 if (os->is_small_section())
1855 return is_bss ? ORDER_SMALL_BSS : ORDER_SMALL_DATA;
1856 if (os->is_large_section())
1857 return is_bss ? ORDER_LARGE_BSS : ORDER_LARGE_DATA;
1859 return is_bss ? ORDER_BSS : ORDER_DATA;
1862 // Attach output sections to segments. This is called after we have
1863 // seen all the input sections.
1866 Layout::attach_sections_to_segments(const Target* target)
1868 for (Section_list::iterator p = this->section_list_.begin();
1869 p != this->section_list_.end();
1871 this->attach_section_to_segment(target, *p);
1873 this->sections_are_attached_ = true;
1876 // Attach an output section to a segment.
1879 Layout::attach_section_to_segment(const Target* target, Output_section* os)
1881 if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
1882 this->unattached_section_list_.push_back(os);
1884 this->attach_allocated_section_to_segment(target, os);
1887 // Attach an allocated output section to a segment.
1890 Layout::attach_allocated_section_to_segment(const Target* target,
1893 elfcpp::Elf_Xword flags = os->flags();
1894 gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
1896 if (parameters->options().relocatable())
1899 // If we have a SECTIONS clause, we can't handle the attachment to
1900 // segments until after we've seen all the sections.
1901 if (this->script_options_->saw_sections_clause())
1904 gold_assert(!this->script_options_->saw_phdrs_clause());
1906 // This output section goes into a PT_LOAD segment.
1908 elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
1910 // If this output section's segment has extra flags that need to be set,
1911 // coming from a linker plugin, do that.
1912 seg_flags |= os->extra_segment_flags();
1914 // Check for --section-start.
1916 bool is_address_set = parameters->options().section_start(os->name(), &addr);
1918 // In general the only thing we really care about for PT_LOAD
1919 // segments is whether or not they are writable or executable,
1920 // so that is how we search for them.
1921 // Large data sections also go into their own PT_LOAD segment.
1922 // People who need segments sorted on some other basis will
1923 // have to use a linker script.
1925 Segment_list::const_iterator p;
1926 if (!os->is_unique_segment())
1928 for (p = this->segment_list_.begin();
1929 p != this->segment_list_.end();
1932 if ((*p)->type() != elfcpp::PT_LOAD)
1934 if ((*p)->is_unique_segment())
1936 if (!parameters->options().omagic()
1937 && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W))
1939 if ((target->isolate_execinstr() || parameters->options().rosegment())
1940 && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X))
1942 // If -Tbss was specified, we need to separate the data and BSS
1944 if (parameters->options().user_set_Tbss())
1946 if ((os->type() == elfcpp::SHT_NOBITS)
1947 == (*p)->has_any_data_sections())
1950 if (os->is_large_data_section() && !(*p)->is_large_data_segment())
1955 if ((*p)->are_addresses_set())
1958 (*p)->add_initial_output_data(os);
1959 (*p)->update_flags_for_output_section(seg_flags);
1960 (*p)->set_addresses(addr, addr);
1964 (*p)->add_output_section_to_load(this, os, seg_flags);
1969 if (p == this->segment_list_.end()
1970 || os->is_unique_segment())
1972 Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
1974 if (os->is_large_data_section())
1975 oseg->set_is_large_data_segment();
1976 oseg->add_output_section_to_load(this, os, seg_flags);
1978 oseg->set_addresses(addr, addr);
1979 // Check if segment should be marked unique. For segments marked
1980 // unique by linker plugins, set the new alignment if specified.
1981 if (os->is_unique_segment())
1983 oseg->set_is_unique_segment();
1984 if (os->segment_alignment() != 0)
1985 oseg->set_minimum_p_align(os->segment_alignment());
1989 // If we see a loadable SHT_NOTE section, we create a PT_NOTE
1991 if (os->type() == elfcpp::SHT_NOTE)
1993 // See if we already have an equivalent PT_NOTE segment.
1994 for (p = this->segment_list_.begin();
1995 p != segment_list_.end();
1998 if ((*p)->type() == elfcpp::PT_NOTE
1999 && (((*p)->flags() & elfcpp::PF_W)
2000 == (seg_flags & elfcpp::PF_W)))
2002 (*p)->add_output_section_to_nonload(os, seg_flags);
2007 if (p == this->segment_list_.end())
2009 Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
2011 oseg->add_output_section_to_nonload(os, seg_flags);
2015 // If we see a loadable SHF_TLS section, we create a PT_TLS
2016 // segment. There can only be one such segment.
2017 if ((flags & elfcpp::SHF_TLS) != 0)
2019 if (this->tls_segment_ == NULL)
2020 this->make_output_segment(elfcpp::PT_TLS, seg_flags);
2021 this->tls_segment_->add_output_section_to_nonload(os, seg_flags);
2024 // If -z relro is in effect, and we see a relro section, we create a
2025 // PT_GNU_RELRO segment. There can only be one such segment.
2026 if (os->is_relro() && parameters->options().relro())
2028 gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
2029 if (this->relro_segment_ == NULL)
2030 this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
2031 this->relro_segment_->add_output_section_to_nonload(os, seg_flags);
2034 // If we see a section named .interp, put it into a PT_INTERP
2035 // segment. This seems broken to me, but this is what GNU ld does,
2036 // and glibc expects it.
2037 if (strcmp(os->name(), ".interp") == 0
2038 && !this->script_options_->saw_phdrs_clause())
2040 if (this->interp_segment_ == NULL)
2041 this->make_output_segment(elfcpp::PT_INTERP, seg_flags);
2043 gold_warning(_("multiple '.interp' sections in input files "
2044 "may cause confusing PT_INTERP segment"));
2045 this->interp_segment_->add_output_section_to_nonload(os, seg_flags);
2049 // Make an output section for a script.
2052 Layout::make_output_section_for_script(
2054 Script_sections::Section_type section_type)
2056 name = this->namepool_.add(name, false, NULL);
2057 elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC;
2058 if (section_type == Script_sections::ST_NOLOAD)
2060 Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
2061 sh_flags, ORDER_INVALID,
2063 os->set_found_in_sections_clause();
2064 if (section_type == Script_sections::ST_NOLOAD)
2065 os->set_is_noload();
2069 // Return the number of segments we expect to see.
2072 Layout::expected_segment_count() const
2074 size_t ret = this->segment_list_.size();
2076 // If we didn't see a SECTIONS clause in a linker script, we should
2077 // already have the complete list of segments. Otherwise we ask the
2078 // SECTIONS clause how many segments it expects, and add in the ones
2079 // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
2081 if (!this->script_options_->saw_sections_clause())
2085 const Script_sections* ss = this->script_options_->script_sections();
2086 return ret + ss->expected_segment_count(this);
2090 // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
2091 // is whether we saw a .note.GNU-stack section in the object file.
2092 // GNU_STACK_FLAGS is the section flags. The flags give the
2093 // protection required for stack memory. We record this in an
2094 // executable as a PT_GNU_STACK segment. If an object file does not
2095 // have a .note.GNU-stack segment, we must assume that it is an old
2096 // object. On some targets that will force an executable stack.
2099 Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags,
2102 if (!seen_gnu_stack)
2104 this->input_without_gnu_stack_note_ = true;
2105 if (parameters->options().warn_execstack()
2106 && parameters->target().is_default_stack_executable())
2107 gold_warning(_("%s: missing .note.GNU-stack section"
2108 " implies executable stack"),
2109 obj->name().c_str());
2113 this->input_with_gnu_stack_note_ = true;
2114 if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
2116 this->input_requires_executable_stack_ = true;
2117 if (parameters->options().warn_execstack())
2118 gold_warning(_("%s: requires executable stack"),
2119 obj->name().c_str());
2124 // Create automatic note sections.
2127 Layout::create_notes()
2129 this->create_gold_note();
2130 this->create_executable_stack_info();
2131 this->create_build_id();
2134 // Create the dynamic sections which are needed before we read the
2138 Layout::create_initial_dynamic_sections(Symbol_table* symtab)
2140 if (parameters->doing_static_link())
2143 this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
2144 elfcpp::SHT_DYNAMIC,
2146 | elfcpp::SHF_WRITE),
2150 // A linker script may discard .dynamic, so check for NULL.
2151 if (this->dynamic_section_ != NULL)
2153 this->dynamic_symbol_ =
2154 symtab->define_in_output_data("_DYNAMIC", NULL,
2155 Symbol_table::PREDEFINED,
2156 this->dynamic_section_, 0, 0,
2157 elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
2158 elfcpp::STV_HIDDEN, 0, false, false);
2160 this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_);
2162 this->dynamic_section_->add_output_section_data(this->dynamic_data_);
2166 // For each output section whose name can be represented as C symbol,
2167 // define __start and __stop symbols for the section. This is a GNU
2171 Layout::define_section_symbols(Symbol_table* symtab)
2173 for (Section_list::const_iterator p = this->section_list_.begin();
2174 p != this->section_list_.end();
2177 const char* const name = (*p)->name();
2178 if (is_cident(name))
2180 const std::string name_string(name);
2181 const std::string start_name(cident_section_start_prefix
2183 const std::string stop_name(cident_section_stop_prefix
2186 symtab->define_in_output_data(start_name.c_str(),
2188 Symbol_table::PREDEFINED,
2194 elfcpp::STV_DEFAULT,
2196 false, // offset_is_from_end
2197 true); // only_if_ref
2199 symtab->define_in_output_data(stop_name.c_str(),
2201 Symbol_table::PREDEFINED,
2207 elfcpp::STV_DEFAULT,
2209 true, // offset_is_from_end
2210 true); // only_if_ref
2215 // Define symbols for group signatures.
2218 Layout::define_group_signatures(Symbol_table* symtab)
2220 for (Group_signatures::iterator p = this->group_signatures_.begin();
2221 p != this->group_signatures_.end();
2224 Symbol* sym = symtab->lookup(p->signature, NULL);
2226 p->section->set_info_symndx(sym);
2229 // Force the name of the group section to the group
2230 // signature, and use the group's section symbol as the
2231 // signature symbol.
2232 if (strcmp(p->section->name(), p->signature) != 0)
2234 const char* name = this->namepool_.add(p->signature,
2236 p->section->set_name(name);
2238 p->section->set_needs_symtab_index();
2239 p->section->set_info_section_symndx(p->section);
2243 this->group_signatures_.clear();
2246 // Find the first read-only PT_LOAD segment, creating one if
2250 Layout::find_first_load_seg(const Target* target)
2252 Output_segment* best = NULL;
2253 for (Segment_list::const_iterator p = this->segment_list_.begin();
2254 p != this->segment_list_.end();
2257 if ((*p)->type() == elfcpp::PT_LOAD
2258 && ((*p)->flags() & elfcpp::PF_R) != 0
2259 && (parameters->options().omagic()
2260 || ((*p)->flags() & elfcpp::PF_W) == 0)
2261 && (!target->isolate_execinstr()
2262 || ((*p)->flags() & elfcpp::PF_X) == 0))
2264 if (best == NULL || this->segment_precedes(*p, best))
2271 gold_assert(!this->script_options_->saw_phdrs_clause());
2273 Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
2278 // Save states of all current output segments. Store saved states
2279 // in SEGMENT_STATES.
2282 Layout::save_segments(Segment_states* segment_states)
2284 for (Segment_list::const_iterator p = this->segment_list_.begin();
2285 p != this->segment_list_.end();
2288 Output_segment* segment = *p;
2290 Output_segment* copy = new Output_segment(*segment);
2291 (*segment_states)[segment] = copy;
2295 // Restore states of output segments and delete any segment not found in
2299 Layout::restore_segments(const Segment_states* segment_states)
2301 // Go through the segment list and remove any segment added in the
2303 this->tls_segment_ = NULL;
2304 this->relro_segment_ = NULL;
2305 Segment_list::iterator list_iter = this->segment_list_.begin();
2306 while (list_iter != this->segment_list_.end())
2308 Output_segment* segment = *list_iter;
2309 Segment_states::const_iterator states_iter =
2310 segment_states->find(segment);
2311 if (states_iter != segment_states->end())
2313 const Output_segment* copy = states_iter->second;
2314 // Shallow copy to restore states.
2317 // Also fix up TLS and RELRO segment pointers as appropriate.
2318 if (segment->type() == elfcpp::PT_TLS)
2319 this->tls_segment_ = segment;
2320 else if (segment->type() == elfcpp::PT_GNU_RELRO)
2321 this->relro_segment_ = segment;
2327 list_iter = this->segment_list_.erase(list_iter);
2328 // This is a segment created during section layout. It should be
2329 // safe to remove it since we should have removed all pointers to it.
2335 // Clean up after relaxation so that sections can be laid out again.
2338 Layout::clean_up_after_relaxation()
2340 // Restore the segments to point state just prior to the relaxation loop.
2341 Script_sections* script_section = this->script_options_->script_sections();
2342 script_section->release_segments();
2343 this->restore_segments(this->segment_states_);
2345 // Reset section addresses and file offsets
2346 for (Section_list::iterator p = this->section_list_.begin();
2347 p != this->section_list_.end();
2350 (*p)->restore_states();
2352 // If an input section changes size because of relaxation,
2353 // we need to adjust the section offsets of all input sections.
2354 // after such a section.
2355 if ((*p)->section_offsets_need_adjustment())
2356 (*p)->adjust_section_offsets();
2358 (*p)->reset_address_and_file_offset();
2361 // Reset special output object address and file offsets.
2362 for (Data_list::iterator p = this->special_output_list_.begin();
2363 p != this->special_output_list_.end();
2365 (*p)->reset_address_and_file_offset();
2367 // A linker script may have created some output section data objects.
2368 // They are useless now.
2369 for (Output_section_data_list::const_iterator p =
2370 this->script_output_section_data_list_.begin();
2371 p != this->script_output_section_data_list_.end();
2374 this->script_output_section_data_list_.clear();
2376 // Special-case fill output objects are recreated each time through
2377 // the relaxation loop.
2378 this->reset_relax_output();
2382 Layout::reset_relax_output()
2384 for (Data_list::const_iterator p = this->relax_output_list_.begin();
2385 p != this->relax_output_list_.end();
2388 this->relax_output_list_.clear();
2391 // Prepare for relaxation.
2394 Layout::prepare_for_relaxation()
2396 // Create an relaxation debug check if in debugging mode.
2397 if (is_debugging_enabled(DEBUG_RELAXATION))
2398 this->relaxation_debug_check_ = new Relaxation_debug_check();
2400 // Save segment states.
2401 this->segment_states_ = new Segment_states();
2402 this->save_segments(this->segment_states_);
2404 for(Section_list::const_iterator p = this->section_list_.begin();
2405 p != this->section_list_.end();
2407 (*p)->save_states();
2409 if (is_debugging_enabled(DEBUG_RELAXATION))
2410 this->relaxation_debug_check_->check_output_data_for_reset_values(
2411 this->section_list_, this->special_output_list_,
2412 this->relax_output_list_);
2414 // Also enable recording of output section data from scripts.
2415 this->record_output_section_data_from_script_ = true;
2418 // If the user set the address of the text segment, that may not be
2419 // compatible with putting the segment headers and file headers into
2420 // that segment. For isolate_execinstr() targets, it's the rodata
2421 // segment rather than text where we might put the headers.
2423 load_seg_unusable_for_headers(const Target* target)
2425 const General_options& options = parameters->options();
2426 if (target->isolate_execinstr())
2427 return (options.user_set_Trodata_segment()
2428 && options.Trodata_segment() % target->abi_pagesize() != 0);
2430 return (options.user_set_Ttext()
2431 && options.Ttext() % target->abi_pagesize() != 0);
2434 // Relaxation loop body: If target has no relaxation, this runs only once
2435 // Otherwise, the target relaxation hook is called at the end of
2436 // each iteration. If the hook returns true, it means re-layout of
2437 // section is required.
2439 // The number of segments created by a linking script without a PHDRS
2440 // clause may be affected by section sizes and alignments. There is
2441 // a remote chance that relaxation causes different number of PT_LOAD
2442 // segments are created and sections are attached to different segments.
2443 // Therefore, we always throw away all segments created during section
2444 // layout. In order to be able to restart the section layout, we keep
2445 // a copy of the segment list right before the relaxation loop and use
2446 // that to restore the segments.
2448 // PASS is the current relaxation pass number.
2449 // SYMTAB is a symbol table.
2450 // PLOAD_SEG is the address of a pointer for the load segment.
2451 // PHDR_SEG is a pointer to the PHDR segment.
2452 // SEGMENT_HEADERS points to the output segment header.
2453 // FILE_HEADER points to the output file header.
2454 // PSHNDX is the address to store the output section index.
2457 Layout::relaxation_loop_body(
2460 Symbol_table* symtab,
2461 Output_segment** pload_seg,
2462 Output_segment* phdr_seg,
2463 Output_segment_headers* segment_headers,
2464 Output_file_header* file_header,
2465 unsigned int* pshndx)
2467 // If this is not the first iteration, we need to clean up after
2468 // relaxation so that we can lay out the sections again.
2470 this->clean_up_after_relaxation();
2472 // If there is a SECTIONS clause, put all the input sections into
2473 // the required order.
2474 Output_segment* load_seg;
2475 if (this->script_options_->saw_sections_clause())
2476 load_seg = this->set_section_addresses_from_script(symtab);
2477 else if (parameters->options().relocatable())
2480 load_seg = this->find_first_load_seg(target);
2482 if (parameters->options().oformat_enum()
2483 != General_options::OBJECT_FORMAT_ELF)
2486 if (load_seg_unusable_for_headers(target))
2492 gold_assert(phdr_seg == NULL
2494 || this->script_options_->saw_sections_clause());
2496 // If the address of the load segment we found has been set by
2497 // --section-start rather than by a script, then adjust the VMA and
2498 // LMA downward if possible to include the file and section headers.
2499 uint64_t header_gap = 0;
2500 if (load_seg != NULL
2501 && load_seg->are_addresses_set()
2502 && !this->script_options_->saw_sections_clause()
2503 && !parameters->options().relocatable())
2505 file_header->finalize_data_size();
2506 segment_headers->finalize_data_size();
2507 size_t sizeof_headers = (file_header->data_size()
2508 + segment_headers->data_size());
2509 const uint64_t abi_pagesize = target->abi_pagesize();
2510 uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers;
2511 hdr_paddr &= ~(abi_pagesize - 1);
2512 uint64_t subtract = load_seg->paddr() - hdr_paddr;
2513 if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract)
2517 load_seg->set_addresses(load_seg->vaddr() - subtract,
2518 load_seg->paddr() - subtract);
2519 header_gap = subtract - sizeof_headers;
2523 // Lay out the segment headers.
2524 if (!parameters->options().relocatable())
2526 gold_assert(segment_headers != NULL);
2527 if (header_gap != 0 && load_seg != NULL)
2529 Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1);
2530 load_seg->add_initial_output_data(z);
2532 if (load_seg != NULL)
2533 load_seg->add_initial_output_data(segment_headers);
2534 if (phdr_seg != NULL)
2535 phdr_seg->add_initial_output_data(segment_headers);
2538 // Lay out the file header.
2539 if (load_seg != NULL)
2540 load_seg->add_initial_output_data(file_header);
2542 if (this->script_options_->saw_phdrs_clause()
2543 && !parameters->options().relocatable())
2545 // Support use of FILEHDRS and PHDRS attachments in a PHDRS
2546 // clause in a linker script.
2547 Script_sections* ss = this->script_options_->script_sections();
2548 ss->put_headers_in_phdrs(file_header, segment_headers);
2551 // We set the output section indexes in set_segment_offsets and
2552 // set_section_indexes.
2555 // Set the file offsets of all the segments, and all the sections
2558 if (!parameters->options().relocatable())
2559 off = this->set_segment_offsets(target, load_seg, pshndx);
2561 off = this->set_relocatable_section_offsets(file_header, pshndx);
2563 // Verify that the dummy relaxation does not change anything.
2564 if (is_debugging_enabled(DEBUG_RELAXATION))
2567 this->relaxation_debug_check_->read_sections(this->section_list_);
2569 this->relaxation_debug_check_->verify_sections(this->section_list_);
2572 *pload_seg = load_seg;
2576 // Search the list of patterns and find the postion of the given section
2577 // name in the output section. If the section name matches a glob
2578 // pattern and a non-glob name, then the non-glob position takes
2579 // precedence. Return 0 if no match is found.
2582 Layout::find_section_order_index(const std::string& section_name)
2584 Unordered_map<std::string, unsigned int>::iterator map_it;
2585 map_it = this->input_section_position_.find(section_name);
2586 if (map_it != this->input_section_position_.end())
2587 return map_it->second;
2589 // Absolute match failed. Linear search the glob patterns.
2590 std::vector<std::string>::iterator it;
2591 for (it = this->input_section_glob_.begin();
2592 it != this->input_section_glob_.end();
2595 if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0)
2597 map_it = this->input_section_position_.find(*it);
2598 gold_assert(map_it != this->input_section_position_.end());
2599 return map_it->second;
2605 // Read the sequence of input sections from the file specified with
2606 // option --section-ordering-file.
2609 Layout::read_layout_from_file()
2611 const char* filename = parameters->options().section_ordering_file();
2617 gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
2618 filename, strerror(errno));
2620 std::getline(in, line); // this chops off the trailing \n, if any
2621 unsigned int position = 1;
2622 this->set_section_ordering_specified();
2626 if (!line.empty() && line[line.length() - 1] == '\r') // Windows
2627 line.resize(line.length() - 1);
2628 // Ignore comments, beginning with '#'
2631 std::getline(in, line);
2634 this->input_section_position_[line] = position;
2635 // Store all glob patterns in a vector.
2636 if (is_wildcard_string(line.c_str()))
2637 this->input_section_glob_.push_back(line);
2639 std::getline(in, line);
2643 // Finalize the layout. When this is called, we have created all the
2644 // output sections and all the output segments which are based on
2645 // input sections. We have several things to do, and we have to do
2646 // them in the right order, so that we get the right results correctly
2649 // 1) Finalize the list of output segments and create the segment
2652 // 2) Finalize the dynamic symbol table and associated sections.
2654 // 3) Determine the final file offset of all the output segments.
2656 // 4) Determine the final file offset of all the SHF_ALLOC output
2659 // 5) Create the symbol table sections and the section name table
2662 // 6) Finalize the symbol table: set symbol values to their final
2663 // value and make a final determination of which symbols are going
2664 // into the output symbol table.
2666 // 7) Create the section table header.
2668 // 8) Determine the final file offset of all the output sections which
2669 // are not SHF_ALLOC, including the section table header.
2671 // 9) Finalize the ELF file header.
2673 // This function returns the size of the output file.
2676 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
2677 Target* target, const Task* task)
2679 target->finalize_sections(this, input_objects, symtab);
2681 this->count_local_symbols(task, input_objects);
2683 this->link_stabs_sections();
2685 Output_segment* phdr_seg = NULL;
2686 if (!parameters->options().relocatable() && !parameters->doing_static_link())
2688 // There was a dynamic object in the link. We need to create
2689 // some information for the dynamic linker.
2691 // Create the PT_PHDR segment which will hold the program
2693 if (!this->script_options_->saw_phdrs_clause())
2694 phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
2696 // Create the dynamic symbol table, including the hash table.
2697 Output_section* dynstr;
2698 std::vector<Symbol*> dynamic_symbols;
2699 unsigned int local_dynamic_count;
2700 Versions versions(*this->script_options()->version_script_info(),
2702 this->create_dynamic_symtab(input_objects, symtab, &dynstr,
2703 &local_dynamic_count, &dynamic_symbols,
2706 // Create the .interp section to hold the name of the
2707 // interpreter, and put it in a PT_INTERP segment. Don't do it
2708 // if we saw a .interp section in an input file.
2709 if ((!parameters->options().shared()
2710 || parameters->options().dynamic_linker() != NULL)
2711 && this->interp_segment_ == NULL)
2712 this->create_interp(target);
2714 // Finish the .dynamic section to hold the dynamic data, and put
2715 // it in a PT_DYNAMIC segment.
2716 this->finish_dynamic_section(input_objects, symtab);
2718 // We should have added everything we need to the dynamic string
2720 this->dynpool_.set_string_offsets();
2722 // Create the version sections. We can't do this until the
2723 // dynamic string table is complete.
2724 this->create_version_sections(&versions, symtab, local_dynamic_count,
2725 dynamic_symbols, dynstr);
2727 // Set the size of the _DYNAMIC symbol. We can't do this until
2728 // after we call create_version_sections.
2729 this->set_dynamic_symbol_size(symtab);
2732 // Create segment headers.
2733 Output_segment_headers* segment_headers =
2734 (parameters->options().relocatable()
2736 : new Output_segment_headers(this->segment_list_));
2738 // Lay out the file header.
2739 Output_file_header* file_header = new Output_file_header(target, symtab,
2742 this->special_output_list_.push_back(file_header);
2743 if (segment_headers != NULL)
2744 this->special_output_list_.push_back(segment_headers);
2746 // Find approriate places for orphan output sections if we are using
2748 if (this->script_options_->saw_sections_clause())
2749 this->place_orphan_sections_in_script();
2751 Output_segment* load_seg;
2756 // Take a snapshot of the section layout as needed.
2757 if (target->may_relax())
2758 this->prepare_for_relaxation();
2760 // Run the relaxation loop to lay out sections.
2763 off = this->relaxation_loop_body(pass, target, symtab, &load_seg,
2764 phdr_seg, segment_headers, file_header,
2768 while (target->may_relax()
2769 && target->relax(pass, input_objects, symtab, this, task));
2771 // If there is a load segment that contains the file and program headers,
2772 // provide a symbol __ehdr_start pointing there.
2773 // A program can use this to examine itself robustly.
2774 Symbol *ehdr_start = symtab->lookup("__ehdr_start");
2775 if (ehdr_start != NULL && ehdr_start->is_predefined())
2777 if (load_seg != NULL)
2778 ehdr_start->set_output_segment(load_seg, Symbol::SEGMENT_START);
2780 ehdr_start->set_undefined();
2783 // Set the file offsets of all the non-data sections we've seen so
2784 // far which don't have to wait for the input sections. We need
2785 // this in order to finalize local symbols in non-allocated
2787 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2789 // Set the section indexes of all unallocated sections seen so far,
2790 // in case any of them are somehow referenced by a symbol.
2791 shndx = this->set_section_indexes(shndx);
2793 // Create the symbol table sections.
2794 this->create_symtab_sections(input_objects, symtab, shndx, &off);
2795 if (!parameters->doing_static_link())
2796 this->assign_local_dynsym_offsets(input_objects);
2798 // Process any symbol assignments from a linker script. This must
2799 // be called after the symbol table has been finalized.
2800 this->script_options_->finalize_symbols(symtab, this);
2802 // Create the incremental inputs sections.
2803 if (this->incremental_inputs_)
2805 this->incremental_inputs_->finalize();
2806 this->create_incremental_info_sections(symtab);
2809 // Create the .shstrtab section.
2810 Output_section* shstrtab_section = this->create_shstrtab();
2812 // Set the file offsets of the rest of the non-data sections which
2813 // don't have to wait for the input sections.
2814 off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
2816 // Now that all sections have been created, set the section indexes
2817 // for any sections which haven't been done yet.
2818 shndx = this->set_section_indexes(shndx);
2820 // Create the section table header.
2821 this->create_shdrs(shstrtab_section, &off);
2823 // If there are no sections which require postprocessing, we can
2824 // handle the section names now, and avoid a resize later.
2825 if (!this->any_postprocessing_sections_)
2827 off = this->set_section_offsets(off,
2828 POSTPROCESSING_SECTIONS_PASS);
2830 this->set_section_offsets(off,
2831 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
2834 file_header->set_section_info(this->section_headers_, shstrtab_section);
2836 // Now we know exactly where everything goes in the output file
2837 // (except for non-allocated sections which require postprocessing).
2838 Output_data::layout_complete();
2840 this->output_file_size_ = off;
2845 // Create a note header following the format defined in the ELF ABI.
2846 // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name
2847 // of the section to create, DESCSZ is the size of the descriptor.
2848 // ALLOCATE is true if the section should be allocated in memory.
2849 // This returns the new note section. It sets *TRAILING_PADDING to
2850 // the number of trailing zero bytes required.
2853 Layout::create_note(const char* name, int note_type,
2854 const char* section_name, size_t descsz,
2855 bool allocate, size_t* trailing_padding)
2857 // Authorities all agree that the values in a .note field should
2858 // be aligned on 4-byte boundaries for 32-bit binaries. However,
2859 // they differ on what the alignment is for 64-bit binaries.
2860 // The GABI says unambiguously they take 8-byte alignment:
2861 // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
2862 // Other documentation says alignment should always be 4 bytes:
2863 // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
2864 // GNU ld and GNU readelf both support the latter (at least as of
2865 // version 2.16.91), and glibc always generates the latter for
2866 // .note.ABI-tag (as of version 1.6), so that's the one we go with
2868 #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
2869 const int size = parameters->target().get_size();
2871 const int size = 32;
2874 // The contents of the .note section.
2875 size_t namesz = strlen(name) + 1;
2876 size_t aligned_namesz = align_address(namesz, size / 8);
2877 size_t aligned_descsz = align_address(descsz, size / 8);
2879 size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
2881 unsigned char* buffer = new unsigned char[notehdrsz];
2882 memset(buffer, 0, notehdrsz);
2884 bool is_big_endian = parameters->target().is_big_endian();
2890 elfcpp::Swap<32, false>::writeval(buffer, namesz);
2891 elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
2892 elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
2896 elfcpp::Swap<32, true>::writeval(buffer, namesz);
2897 elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
2898 elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
2901 else if (size == 64)
2905 elfcpp::Swap<64, false>::writeval(buffer, namesz);
2906 elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
2907 elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
2911 elfcpp::Swap<64, true>::writeval(buffer, namesz);
2912 elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
2913 elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
2919 memcpy(buffer + 3 * (size / 8), name, namesz);
2921 elfcpp::Elf_Xword flags = 0;
2922 Output_section_order order = ORDER_INVALID;
2925 flags = elfcpp::SHF_ALLOC;
2926 order = ORDER_RO_NOTE;
2928 Output_section* os = this->choose_output_section(NULL, section_name,
2930 flags, false, order, false);
2934 Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
2937 os->add_output_section_data(posd);
2939 *trailing_padding = aligned_descsz - descsz;
2944 // For an executable or shared library, create a note to record the
2945 // version of gold used to create the binary.
2948 Layout::create_gold_note()
2950 if (parameters->options().relocatable()
2951 || parameters->incremental_update())
2954 std::string desc = std::string("gold ") + gold::get_version_string();
2956 size_t trailing_padding;
2957 Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
2958 ".note.gnu.gold-version", desc.size(),
2959 false, &trailing_padding);
2963 Output_section_data* posd = new Output_data_const(desc, 4);
2964 os->add_output_section_data(posd);
2966 if (trailing_padding > 0)
2968 posd = new Output_data_zero_fill(trailing_padding, 0);
2969 os->add_output_section_data(posd);
2973 // Record whether the stack should be executable. This can be set
2974 // from the command line using the -z execstack or -z noexecstack
2975 // options. Otherwise, if any input file has a .note.GNU-stack
2976 // section with the SHF_EXECINSTR flag set, the stack should be
2977 // executable. Otherwise, if at least one input file a
2978 // .note.GNU-stack section, and some input file has no .note.GNU-stack
2979 // section, we use the target default for whether the stack should be
2980 // executable. Otherwise, we don't generate a stack note. When
2981 // generating a object file, we create a .note.GNU-stack section with
2982 // the appropriate marking. When generating an executable or shared
2983 // library, we create a PT_GNU_STACK segment.
2986 Layout::create_executable_stack_info()
2988 bool is_stack_executable;
2989 if (parameters->options().is_execstack_set())
2991 is_stack_executable = parameters->options().is_stack_executable();
2992 if (!is_stack_executable
2993 && this->input_requires_executable_stack_
2994 && parameters->options().warn_execstack())
2995 gold_warning(_("one or more inputs require executable stack, "
2996 "but -z noexecstack was given"));
2998 else if (!this->input_with_gnu_stack_note_)
3002 if (this->input_requires_executable_stack_)
3003 is_stack_executable = true;
3004 else if (this->input_without_gnu_stack_note_)
3005 is_stack_executable =
3006 parameters->target().is_default_stack_executable();
3008 is_stack_executable = false;
3011 if (parameters->options().relocatable())
3013 const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
3014 elfcpp::Elf_Xword flags = 0;
3015 if (is_stack_executable)
3016 flags |= elfcpp::SHF_EXECINSTR;
3017 this->make_output_section(name, elfcpp::SHT_PROGBITS, flags,
3018 ORDER_INVALID, false);
3022 if (this->script_options_->saw_phdrs_clause())
3024 int flags = elfcpp::PF_R | elfcpp::PF_W;
3025 if (is_stack_executable)
3026 flags |= elfcpp::PF_X;
3027 this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
3031 // If --build-id was used, set up the build ID note.
3034 Layout::create_build_id()
3036 if (!parameters->options().user_set_build_id())
3039 const char* style = parameters->options().build_id();
3040 if (strcmp(style, "none") == 0)
3043 // Set DESCSZ to the size of the note descriptor. When possible,
3044 // set DESC to the note descriptor contents.
3047 if (strcmp(style, "md5") == 0)
3049 else if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0))
3051 else if (strcmp(style, "uuid") == 0)
3053 const size_t uuidsz = 128 / 8;
3055 char buffer[uuidsz];
3056 memset(buffer, 0, uuidsz);
3058 int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
3060 gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
3064 ssize_t got = ::read(descriptor, buffer, uuidsz);
3065 release_descriptor(descriptor, true);
3067 gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
3068 else if (static_cast<size_t>(got) != uuidsz)
3069 gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
3073 desc.assign(buffer, uuidsz);
3076 else if (strncmp(style, "0x", 2) == 0)
3079 const char* p = style + 2;
3082 if (hex_p(p[0]) && hex_p(p[1]))
3084 char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
3088 else if (*p == '-' || *p == ':')
3091 gold_fatal(_("--build-id argument '%s' not a valid hex number"),
3094 descsz = desc.size();
3097 gold_fatal(_("unrecognized --build-id argument '%s'"), style);
3100 size_t trailing_padding;
3101 Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
3102 ".note.gnu.build-id", descsz, true,
3109 // We know the value already, so we fill it in now.
3110 gold_assert(desc.size() == descsz);
3112 Output_section_data* posd = new Output_data_const(desc, 4);
3113 os->add_output_section_data(posd);
3115 if (trailing_padding != 0)
3117 posd = new Output_data_zero_fill(trailing_padding, 0);
3118 os->add_output_section_data(posd);
3123 // We need to compute a checksum after we have completed the
3125 gold_assert(trailing_padding == 0);
3126 this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
3127 os->add_output_section_data(this->build_id_note_);
3131 // If we have both .stabXX and .stabXXstr sections, then the sh_link
3132 // field of the former should point to the latter. I'm not sure who
3133 // started this, but the GNU linker does it, and some tools depend
3137 Layout::link_stabs_sections()
3139 if (!this->have_stabstr_section_)
3142 for (Section_list::iterator p = this->section_list_.begin();
3143 p != this->section_list_.end();
3146 if ((*p)->type() != elfcpp::SHT_STRTAB)
3149 const char* name = (*p)->name();
3150 if (strncmp(name, ".stab", 5) != 0)
3153 size_t len = strlen(name);
3154 if (strcmp(name + len - 3, "str") != 0)
3157 std::string stab_name(name, len - 3);
3158 Output_section* stab_sec;
3159 stab_sec = this->find_output_section(stab_name.c_str());
3160 if (stab_sec != NULL)
3161 stab_sec->set_link_section(*p);
3165 // Create .gnu_incremental_inputs and related sections needed
3166 // for the next run of incremental linking to check what has changed.
3169 Layout::create_incremental_info_sections(Symbol_table* symtab)
3171 Incremental_inputs* incr = this->incremental_inputs_;
3173 gold_assert(incr != NULL);
3175 // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections.
3176 incr->create_data_sections(symtab);
3178 // Add the .gnu_incremental_inputs section.
3179 const char* incremental_inputs_name =
3180 this->namepool_.add(".gnu_incremental_inputs", false, NULL);
3181 Output_section* incremental_inputs_os =
3182 this->make_output_section(incremental_inputs_name,
3183 elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0,
3184 ORDER_INVALID, false);
3185 incremental_inputs_os->add_output_section_data(incr->inputs_section());
3187 // Add the .gnu_incremental_symtab section.
3188 const char* incremental_symtab_name =
3189 this->namepool_.add(".gnu_incremental_symtab", false, NULL);
3190 Output_section* incremental_symtab_os =
3191 this->make_output_section(incremental_symtab_name,
3192 elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0,
3193 ORDER_INVALID, false);
3194 incremental_symtab_os->add_output_section_data(incr->symtab_section());
3195 incremental_symtab_os->set_entsize(4);
3197 // Add the .gnu_incremental_relocs section.
3198 const char* incremental_relocs_name =
3199 this->namepool_.add(".gnu_incremental_relocs", false, NULL);
3200 Output_section* incremental_relocs_os =
3201 this->make_output_section(incremental_relocs_name,
3202 elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0,
3203 ORDER_INVALID, false);
3204 incremental_relocs_os->add_output_section_data(incr->relocs_section());
3205 incremental_relocs_os->set_entsize(incr->relocs_entsize());
3207 // Add the .gnu_incremental_got_plt section.
3208 const char* incremental_got_plt_name =
3209 this->namepool_.add(".gnu_incremental_got_plt", false, NULL);
3210 Output_section* incremental_got_plt_os =
3211 this->make_output_section(incremental_got_plt_name,
3212 elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0,
3213 ORDER_INVALID, false);
3214 incremental_got_plt_os->add_output_section_data(incr->got_plt_section());
3216 // Add the .gnu_incremental_strtab section.
3217 const char* incremental_strtab_name =
3218 this->namepool_.add(".gnu_incremental_strtab", false, NULL);
3219 Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name,
3220 elfcpp::SHT_STRTAB, 0,
3221 ORDER_INVALID, false);
3222 Output_data_strtab* strtab_data =
3223 new Output_data_strtab(incr->get_stringpool());
3224 incremental_strtab_os->add_output_section_data(strtab_data);
3226 incremental_inputs_os->set_after_input_sections();
3227 incremental_symtab_os->set_after_input_sections();
3228 incremental_relocs_os->set_after_input_sections();
3229 incremental_got_plt_os->set_after_input_sections();
3231 incremental_inputs_os->set_link_section(incremental_strtab_os);
3232 incremental_symtab_os->set_link_section(incremental_inputs_os);
3233 incremental_relocs_os->set_link_section(incremental_inputs_os);
3234 incremental_got_plt_os->set_link_section(incremental_inputs_os);
3237 // Return whether SEG1 should be before SEG2 in the output file. This
3238 // is based entirely on the segment type and flags. When this is
3239 // called the segment addresses have normally not yet been set.
3242 Layout::segment_precedes(const Output_segment* seg1,
3243 const Output_segment* seg2)
3245 elfcpp::Elf_Word type1 = seg1->type();
3246 elfcpp::Elf_Word type2 = seg2->type();
3248 // The single PT_PHDR segment is required to precede any loadable
3249 // segment. We simply make it always first.
3250 if (type1 == elfcpp::PT_PHDR)
3252 gold_assert(type2 != elfcpp::PT_PHDR);
3255 if (type2 == elfcpp::PT_PHDR)
3258 // The single PT_INTERP segment is required to precede any loadable
3259 // segment. We simply make it always second.
3260 if (type1 == elfcpp::PT_INTERP)
3262 gold_assert(type2 != elfcpp::PT_INTERP);
3265 if (type2 == elfcpp::PT_INTERP)
3268 // We then put PT_LOAD segments before any other segments.
3269 if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
3271 if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
3274 // We put the PT_TLS segment last except for the PT_GNU_RELRO
3275 // segment, because that is where the dynamic linker expects to find
3276 // it (this is just for efficiency; other positions would also work
3278 if (type1 == elfcpp::PT_TLS
3279 && type2 != elfcpp::PT_TLS
3280 && type2 != elfcpp::PT_GNU_RELRO)
3282 if (type2 == elfcpp::PT_TLS
3283 && type1 != elfcpp::PT_TLS
3284 && type1 != elfcpp::PT_GNU_RELRO)
3287 // We put the PT_GNU_RELRO segment last, because that is where the
3288 // dynamic linker expects to find it (as with PT_TLS, this is just
3290 if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
3292 if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
3295 const elfcpp::Elf_Word flags1 = seg1->flags();
3296 const elfcpp::Elf_Word flags2 = seg2->flags();
3298 // The order of non-PT_LOAD segments is unimportant. We simply sort
3299 // by the numeric segment type and flags values. There should not
3300 // be more than one segment with the same type and flags, except
3301 // when a linker script specifies such.
3302 if (type1 != elfcpp::PT_LOAD)
3305 return type1 < type2;
3306 gold_assert(flags1 != flags2
3307 || this->script_options_->saw_phdrs_clause());
3308 return flags1 < flags2;
3311 // If the addresses are set already, sort by load address.
3312 if (seg1->are_addresses_set())
3314 if (!seg2->are_addresses_set())
3317 unsigned int section_count1 = seg1->output_section_count();
3318 unsigned int section_count2 = seg2->output_section_count();
3319 if (section_count1 == 0 && section_count2 > 0)
3321 if (section_count1 > 0 && section_count2 == 0)
3324 uint64_t paddr1 = (seg1->are_addresses_set()
3326 : seg1->first_section_load_address());
3327 uint64_t paddr2 = (seg2->are_addresses_set()
3329 : seg2->first_section_load_address());
3331 if (paddr1 != paddr2)
3332 return paddr1 < paddr2;
3334 else if (seg2->are_addresses_set())
3337 // A segment which holds large data comes after a segment which does
3338 // not hold large data.
3339 if (seg1->is_large_data_segment())
3341 if (!seg2->is_large_data_segment())
3344 else if (seg2->is_large_data_segment())
3347 // Otherwise, we sort PT_LOAD segments based on the flags. Readonly
3348 // segments come before writable segments. Then writable segments
3349 // with data come before writable segments without data. Then
3350 // executable segments come before non-executable segments. Then
3351 // the unlikely case of a non-readable segment comes before the
3352 // normal case of a readable segment. If there are multiple
3353 // segments with the same type and flags, we require that the
3354 // address be set, and we sort by virtual address and then physical
3356 if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
3357 return (flags1 & elfcpp::PF_W) == 0;
3358 if ((flags1 & elfcpp::PF_W) != 0
3359 && seg1->has_any_data_sections() != seg2->has_any_data_sections())
3360 return seg1->has_any_data_sections();
3361 if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
3362 return (flags1 & elfcpp::PF_X) != 0;
3363 if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
3364 return (flags1 & elfcpp::PF_R) == 0;
3366 // We shouldn't get here--we shouldn't create segments which we
3367 // can't distinguish. Unless of course we are using a weird linker
3368 // script or overlapping --section-start options. We could also get
3369 // here if plugins want unique segments for subsets of sections.
3370 gold_assert(this->script_options_->saw_phdrs_clause()
3371 || parameters->options().any_section_start()
3372 || this->is_unique_segment_for_sections_specified());
3376 // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE.
3379 align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize)
3381 uint64_t unsigned_off = off;
3382 uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
3383 | (addr & (abi_pagesize - 1)));
3384 if (aligned_off < unsigned_off)
3385 aligned_off += abi_pagesize;
3389 // On targets where the text segment contains only executable code,
3390 // a non-executable segment is never the text segment.
3393 is_text_segment(const Target* target, const Output_segment* seg)
3395 elfcpp::Elf_Xword flags = seg->flags();
3396 if ((flags & elfcpp::PF_W) != 0)
3398 if ((flags & elfcpp::PF_X) == 0)
3399 return !target->isolate_execinstr();
3403 // Set the file offsets of all the segments, and all the sections they
3404 // contain. They have all been created. LOAD_SEG must be be laid out
3405 // first. Return the offset of the data to follow.
3408 Layout::set_segment_offsets(const Target* target, Output_segment* load_seg,
3409 unsigned int* pshndx)
3411 // Sort them into the final order. We use a stable sort so that we
3412 // don't randomize the order of indistinguishable segments created
3413 // by linker scripts.
3414 std::stable_sort(this->segment_list_.begin(), this->segment_list_.end(),
3415 Layout::Compare_segments(this));
3417 // Find the PT_LOAD segments, and set their addresses and offsets
3418 // and their section's addresses and offsets.
3419 uint64_t start_addr;
3420 if (parameters->options().user_set_Ttext())
3421 start_addr = parameters->options().Ttext();
3422 else if (parameters->options().output_is_position_independent())
3425 start_addr = target->default_text_segment_address();
3427 uint64_t addr = start_addr;
3430 // If LOAD_SEG is NULL, then the file header and segment headers
3431 // will not be loadable. But they still need to be at offset 0 in
3432 // the file. Set their offsets now.
3433 if (load_seg == NULL)
3435 for (Data_list::iterator p = this->special_output_list_.begin();
3436 p != this->special_output_list_.end();
3439 off = align_address(off, (*p)->addralign());
3440 (*p)->set_address_and_file_offset(0, off);
3441 off += (*p)->data_size();
3445 unsigned int increase_relro = this->increase_relro_;
3446 if (this->script_options_->saw_sections_clause())
3449 const bool check_sections = parameters->options().check_sections();
3450 Output_segment* last_load_segment = NULL;
3452 unsigned int shndx_begin = *pshndx;
3453 unsigned int shndx_load_seg = *pshndx;
3455 for (Segment_list::iterator p = this->segment_list_.begin();
3456 p != this->segment_list_.end();
3459 if ((*p)->type() == elfcpp::PT_LOAD)
3461 if (target->isolate_execinstr())
3463 // When we hit the segment that should contain the
3464 // file headers, reset the file offset so we place
3465 // it and subsequent segments appropriately.
3466 // We'll fix up the preceding segments below.
3474 shndx_load_seg = *pshndx;
3480 // Verify that the file headers fall into the first segment.
3481 if (load_seg != NULL && load_seg != *p)
3486 bool are_addresses_set = (*p)->are_addresses_set();
3487 if (are_addresses_set)
3489 // When it comes to setting file offsets, we care about
3490 // the physical address.
3491 addr = (*p)->paddr();
3493 else if (parameters->options().user_set_Ttext()
3494 && (parameters->options().omagic()
3495 || is_text_segment(target, *p)))
3497 are_addresses_set = true;
3499 else if (parameters->options().user_set_Trodata_segment()
3500 && ((*p)->flags() & (elfcpp::PF_W | elfcpp::PF_X)) == 0)
3502 addr = parameters->options().Trodata_segment();
3503 are_addresses_set = true;
3505 else if (parameters->options().user_set_Tdata()
3506 && ((*p)->flags() & elfcpp::PF_W) != 0
3507 && (!parameters->options().user_set_Tbss()
3508 || (*p)->has_any_data_sections()))
3510 addr = parameters->options().Tdata();
3511 are_addresses_set = true;
3513 else if (parameters->options().user_set_Tbss()
3514 && ((*p)->flags() & elfcpp::PF_W) != 0
3515 && !(*p)->has_any_data_sections())
3517 addr = parameters->options().Tbss();
3518 are_addresses_set = true;
3521 uint64_t orig_addr = addr;
3522 uint64_t orig_off = off;
3524 uint64_t aligned_addr = 0;
3525 uint64_t abi_pagesize = target->abi_pagesize();
3526 uint64_t common_pagesize = target->common_pagesize();
3528 if (!parameters->options().nmagic()
3529 && !parameters->options().omagic())
3530 (*p)->set_minimum_p_align(abi_pagesize);
3532 if (!are_addresses_set)
3534 // Skip the address forward one page, maintaining the same
3535 // position within the page. This lets us store both segments
3536 // overlapping on a single page in the file, but the loader will
3537 // put them on different pages in memory. We will revisit this
3538 // decision once we know the size of the segment.
3540 uint64_t max_align = (*p)->maximum_alignment();
3541 if (max_align > abi_pagesize)
3542 addr = align_address(addr, max_align);
3543 aligned_addr = addr;
3547 // This is the segment that will contain the file
3548 // headers, so its offset will have to be exactly zero.
3549 gold_assert(orig_off == 0);
3551 // If the target wants a fixed minimum distance from the
3552 // text segment to the read-only segment, move up now.
3554 start_addr + (parameters->options().user_set_rosegment_gap()
3555 ? parameters->options().rosegment_gap()
3556 : target->rosegment_gap());
3557 if (addr < min_addr)
3560 // But this is not the first segment! To make its
3561 // address congruent with its offset, that address better
3562 // be aligned to the ABI-mandated page size.
3563 addr = align_address(addr, abi_pagesize);
3564 aligned_addr = addr;
3568 if ((addr & (abi_pagesize - 1)) != 0)
3569 addr = addr + abi_pagesize;
3571 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3575 if (!parameters->options().nmagic()
3576 && !parameters->options().omagic())
3578 // Here we are also taking care of the case when
3579 // the maximum segment alignment is larger than the page size.
3580 off = align_file_offset(off, addr,
3581 std::max(abi_pagesize,
3582 (*p)->maximum_alignment()));
3586 // This is -N or -n with a section script which prevents
3587 // us from using a load segment. We need to ensure that
3588 // the file offset is aligned to the alignment of the
3589 // segment. This is because the linker script
3590 // implicitly assumed a zero offset. If we don't align
3591 // here, then the alignment of the sections in the
3592 // linker script may not match the alignment of the
3593 // sections in the set_section_addresses call below,
3594 // causing an error about dot moving backward.
3595 off = align_address(off, (*p)->maximum_alignment());
3598 unsigned int shndx_hold = *pshndx;
3599 bool has_relro = false;
3600 uint64_t new_addr = (*p)->set_section_addresses(target, this,
3606 // Now that we know the size of this segment, we may be able
3607 // to save a page in memory, at the cost of wasting some
3608 // file space, by instead aligning to the start of a new
3609 // page. Here we use the real machine page size rather than
3610 // the ABI mandated page size. If the segment has been
3611 // aligned so that the relro data ends at a page boundary,
3612 // we do not try to realign it.
3614 if (!are_addresses_set
3616 && aligned_addr != addr
3617 && !parameters->incremental())
3619 uint64_t first_off = (common_pagesize
3621 & (common_pagesize - 1)));
3622 uint64_t last_off = new_addr & (common_pagesize - 1);
3625 && ((aligned_addr & ~ (common_pagesize - 1))
3626 != (new_addr & ~ (common_pagesize - 1)))
3627 && first_off + last_off <= common_pagesize)
3629 *pshndx = shndx_hold;
3630 addr = align_address(aligned_addr, common_pagesize);
3631 addr = align_address(addr, (*p)->maximum_alignment());
3632 if ((addr & (abi_pagesize - 1)) != 0)
3633 addr = addr + abi_pagesize;
3634 off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
3635 off = align_file_offset(off, addr, abi_pagesize);
3637 increase_relro = this->increase_relro_;
3638 if (this->script_options_->saw_sections_clause())
3642 new_addr = (*p)->set_section_addresses(target, this,
3652 // Implement --check-sections. We know that the segments
3653 // are sorted by LMA.
3654 if (check_sections && last_load_segment != NULL)
3656 gold_assert(last_load_segment->paddr() <= (*p)->paddr());
3657 if (last_load_segment->paddr() + last_load_segment->memsz()
3660 unsigned long long lb1 = last_load_segment->paddr();
3661 unsigned long long le1 = lb1 + last_load_segment->memsz();
3662 unsigned long long lb2 = (*p)->paddr();
3663 unsigned long long le2 = lb2 + (*p)->memsz();
3664 gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
3665 "[0x%llx -> 0x%llx]"),
3666 lb1, le1, lb2, le2);
3669 last_load_segment = *p;
3673 if (load_seg != NULL && target->isolate_execinstr())
3675 // Process the early segments again, setting their file offsets
3676 // so they land after the segments starting at LOAD_SEG.
3677 off = align_file_offset(off, 0, target->abi_pagesize());
3679 this->reset_relax_output();
3681 for (Segment_list::iterator p = this->segment_list_.begin();
3685 if ((*p)->type() == elfcpp::PT_LOAD)
3687 // We repeat the whole job of assigning addresses and
3688 // offsets, but we really only want to change the offsets and
3689 // must ensure that the addresses all come out the same as
3690 // they did the first time through.
3691 bool has_relro = false;
3692 const uint64_t old_addr = (*p)->vaddr();
3693 const uint64_t old_end = old_addr + (*p)->memsz();
3694 uint64_t new_addr = (*p)->set_section_addresses(target, this,
3700 gold_assert(new_addr == old_end);
3704 gold_assert(shndx_begin == shndx_load_seg);
3707 // Handle the non-PT_LOAD segments, setting their offsets from their
3708 // section's offsets.
3709 for (Segment_list::iterator p = this->segment_list_.begin();
3710 p != this->segment_list_.end();
3713 if ((*p)->type() != elfcpp::PT_LOAD)
3714 (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO
3719 // Set the TLS offsets for each section in the PT_TLS segment.
3720 if (this->tls_segment_ != NULL)
3721 this->tls_segment_->set_tls_offsets();
3726 // Set the offsets of all the allocated sections when doing a
3727 // relocatable link. This does the same jobs as set_segment_offsets,
3728 // only for a relocatable link.
3731 Layout::set_relocatable_section_offsets(Output_data* file_header,
3732 unsigned int* pshndx)
3736 file_header->set_address_and_file_offset(0, 0);
3737 off += file_header->data_size();
3739 for (Section_list::iterator p = this->section_list_.begin();
3740 p != this->section_list_.end();
3743 // We skip unallocated sections here, except that group sections
3744 // have to come first.
3745 if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
3746 && (*p)->type() != elfcpp::SHT_GROUP)
3749 off = align_address(off, (*p)->addralign());
3751 // The linker script might have set the address.
3752 if (!(*p)->is_address_valid())
3753 (*p)->set_address(0);
3754 (*p)->set_file_offset(off);
3755 (*p)->finalize_data_size();
3756 if ((*p)->type() != elfcpp::SHT_NOBITS)
3757 off += (*p)->data_size();
3759 (*p)->set_out_shndx(*pshndx);
3766 // Set the file offset of all the sections not associated with a
3770 Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
3772 off_t startoff = off;
3775 for (Section_list::iterator p = this->unattached_section_list_.begin();
3776 p != this->unattached_section_list_.end();
3779 // The symtab section is handled in create_symtab_sections.
3780 if (*p == this->symtab_section_)
3783 // If we've already set the data size, don't set it again.
3784 if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
3787 if (pass == BEFORE_INPUT_SECTIONS_PASS
3788 && (*p)->requires_postprocessing())
3790 (*p)->create_postprocessing_buffer();
3791 this->any_postprocessing_sections_ = true;
3794 if (pass == BEFORE_INPUT_SECTIONS_PASS
3795 && (*p)->after_input_sections())
3797 else if (pass == POSTPROCESSING_SECTIONS_PASS
3798 && (!(*p)->after_input_sections()
3799 || (*p)->type() == elfcpp::SHT_STRTAB))
3801 else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
3802 && (!(*p)->after_input_sections()
3803 || (*p)->type() != elfcpp::SHT_STRTAB))
3806 if (!parameters->incremental_update())
3808 off = align_address(off, (*p)->addralign());
3809 (*p)->set_file_offset(off);
3810 (*p)->finalize_data_size();
3814 // Incremental update: allocate file space from free list.
3815 (*p)->pre_finalize_data_size();
3816 off_t current_size = (*p)->current_data_size();
3817 off = this->allocate(current_size, (*p)->addralign(), startoff);
3820 if (is_debugging_enabled(DEBUG_INCREMENTAL))
3821 this->free_list_.dump();
3822 gold_assert((*p)->output_section() != NULL);
3823 gold_fallback(_("out of patch space for section %s; "
3824 "relink with --incremental-full"),
3825 (*p)->output_section()->name());
3827 (*p)->set_file_offset(off);
3828 (*p)->finalize_data_size();
3829 if ((*p)->data_size() > current_size)
3831 gold_assert((*p)->output_section() != NULL);
3832 gold_fallback(_("%s: section changed size; "
3833 "relink with --incremental-full"),
3834 (*p)->output_section()->name());
3836 gold_debug(DEBUG_INCREMENTAL,
3837 "set_section_offsets: %08lx %08lx %s",
3838 static_cast<long>(off),
3839 static_cast<long>((*p)->data_size()),
3840 ((*p)->output_section() != NULL
3841 ? (*p)->output_section()->name() : "(special)"));
3844 off += (*p)->data_size();
3848 // At this point the name must be set.
3849 if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
3850 this->namepool_.add((*p)->name(), false, NULL);
3855 // Set the section indexes of all the sections not associated with a
3859 Layout::set_section_indexes(unsigned int shndx)
3861 for (Section_list::iterator p = this->unattached_section_list_.begin();
3862 p != this->unattached_section_list_.end();
3865 if (!(*p)->has_out_shndx())
3867 (*p)->set_out_shndx(shndx);
3874 // Set the section addresses according to the linker script. This is
3875 // only called when we see a SECTIONS clause. This returns the
3876 // program segment which should hold the file header and segment
3877 // headers, if any. It will return NULL if they should not be in a
3881 Layout::set_section_addresses_from_script(Symbol_table* symtab)
3883 Script_sections* ss = this->script_options_->script_sections();
3884 gold_assert(ss->saw_sections_clause());
3885 return this->script_options_->set_section_addresses(symtab, this);
3888 // Place the orphan sections in the linker script.
3891 Layout::place_orphan_sections_in_script()
3893 Script_sections* ss = this->script_options_->script_sections();
3894 gold_assert(ss->saw_sections_clause());
3896 // Place each orphaned output section in the script.
3897 for (Section_list::iterator p = this->section_list_.begin();
3898 p != this->section_list_.end();
3901 if (!(*p)->found_in_sections_clause())
3902 ss->place_orphan(*p);
3906 // Count the local symbols in the regular symbol table and the dynamic
3907 // symbol table, and build the respective string pools.
3910 Layout::count_local_symbols(const Task* task,
3911 const Input_objects* input_objects)
3913 // First, figure out an upper bound on the number of symbols we'll
3914 // be inserting into each pool. This helps us create the pools with
3915 // the right size, to avoid unnecessary hashtable resizing.
3916 unsigned int symbol_count = 0;
3917 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3918 p != input_objects->relobj_end();
3920 symbol_count += (*p)->local_symbol_count();
3922 // Go from "upper bound" to "estimate." We overcount for two
3923 // reasons: we double-count symbols that occur in more than one
3924 // object file, and we count symbols that are dropped from the
3925 // output. Add it all together and assume we overcount by 100%.
3928 // We assume all symbols will go into both the sympool and dynpool.
3929 this->sympool_.reserve(symbol_count);
3930 this->dynpool_.reserve(symbol_count);
3932 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3933 p != input_objects->relobj_end();
3936 Task_lock_obj<Object> tlo(task, *p);
3937 (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
3941 // Create the symbol table sections. Here we also set the final
3942 // values of the symbols. At this point all the loadable sections are
3943 // fully laid out. SHNUM is the number of sections so far.
3946 Layout::create_symtab_sections(const Input_objects* input_objects,
3947 Symbol_table* symtab,
3953 if (parameters->target().get_size() == 32)
3955 symsize = elfcpp::Elf_sizes<32>::sym_size;
3958 else if (parameters->target().get_size() == 64)
3960 symsize = elfcpp::Elf_sizes<64>::sym_size;
3966 // Compute file offsets relative to the start of the symtab section.
3969 // Save space for the dummy symbol at the start of the section. We
3970 // never bother to write this out--it will just be left as zero.
3972 unsigned int local_symbol_index = 1;
3974 // Add STT_SECTION symbols for each Output section which needs one.
3975 for (Section_list::iterator p = this->section_list_.begin();
3976 p != this->section_list_.end();
3979 if (!(*p)->needs_symtab_index())
3980 (*p)->set_symtab_index(-1U);
3983 (*p)->set_symtab_index(local_symbol_index);
3984 ++local_symbol_index;
3989 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
3990 p != input_objects->relobj_end();
3993 unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
3995 off += (index - local_symbol_index) * symsize;
3996 local_symbol_index = index;
3999 unsigned int local_symcount = local_symbol_index;
4000 gold_assert(static_cast<off_t>(local_symcount * symsize) == off);
4003 size_t dyn_global_index;
4005 if (this->dynsym_section_ == NULL)
4008 dyn_global_index = 0;
4013 dyn_global_index = this->dynsym_section_->info();
4014 off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
4015 dynoff = this->dynsym_section_->offset() + locsize;
4016 dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
4017 gold_assert(static_cast<off_t>(dyncount * symsize)
4018 == this->dynsym_section_->data_size() - locsize);
4021 off_t global_off = off;
4022 off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
4023 &this->sympool_, &local_symcount);
4025 if (!parameters->options().strip_all())
4027 this->sympool_.set_string_offsets();
4029 const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
4030 Output_section* osymtab = this->make_output_section(symtab_name,
4034 this->symtab_section_ = osymtab;
4036 Output_section_data* pos = new Output_data_fixed_space(off, align,
4038 osymtab->add_output_section_data(pos);
4040 // We generate a .symtab_shndx section if we have more than
4041 // SHN_LORESERVE sections. Technically it is possible that we
4042 // don't need one, because it is possible that there are no
4043 // symbols in any of sections with indexes larger than
4044 // SHN_LORESERVE. That is probably unusual, though, and it is
4045 // easier to always create one than to compute section indexes
4046 // twice (once here, once when writing out the symbols).
4047 if (shnum >= elfcpp::SHN_LORESERVE)
4049 const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
4051 Output_section* osymtab_xindex =
4052 this->make_output_section(symtab_xindex_name,
4053 elfcpp::SHT_SYMTAB_SHNDX, 0,
4054 ORDER_INVALID, false);
4056 size_t symcount = off / symsize;
4057 this->symtab_xindex_ = new Output_symtab_xindex(symcount);
4059 osymtab_xindex->add_output_section_data(this->symtab_xindex_);
4061 osymtab_xindex->set_link_section(osymtab);
4062 osymtab_xindex->set_addralign(4);
4063 osymtab_xindex->set_entsize(4);
4065 osymtab_xindex->set_after_input_sections();
4067 // This tells the driver code to wait until the symbol table
4068 // has written out before writing out the postprocessing
4069 // sections, including the .symtab_shndx section.
4070 this->any_postprocessing_sections_ = true;
4073 const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
4074 Output_section* ostrtab = this->make_output_section(strtab_name,
4079 Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
4080 ostrtab->add_output_section_data(pstr);
4083 if (!parameters->incremental_update())
4084 symtab_off = align_address(*poff, align);
4087 symtab_off = this->allocate(off, align, *poff);
4089 gold_fallback(_("out of patch space for symbol table; "
4090 "relink with --incremental-full"));
4091 gold_debug(DEBUG_INCREMENTAL,
4092 "create_symtab_sections: %08lx %08lx .symtab",
4093 static_cast<long>(symtab_off),
4094 static_cast<long>(off));
4097 symtab->set_file_offset(symtab_off + global_off);
4098 osymtab->set_file_offset(symtab_off);
4099 osymtab->finalize_data_size();
4100 osymtab->set_link_section(ostrtab);
4101 osymtab->set_info(local_symcount);
4102 osymtab->set_entsize(symsize);
4104 if (symtab_off + off > *poff)
4105 *poff = symtab_off + off;
4109 // Create the .shstrtab section, which holds the names of the
4110 // sections. At the time this is called, we have created all the
4111 // output sections except .shstrtab itself.
4114 Layout::create_shstrtab()
4116 // FIXME: We don't need to create a .shstrtab section if we are
4117 // stripping everything.
4119 const char* name = this->namepool_.add(".shstrtab", false, NULL);
4121 Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0,
4122 ORDER_INVALID, false);
4124 if (strcmp(parameters->options().compress_debug_sections(), "none") != 0)
4126 // We can't write out this section until we've set all the
4127 // section names, and we don't set the names of compressed
4128 // output sections until relocations are complete. FIXME: With
4129 // the current names we use, this is unnecessary.
4130 os->set_after_input_sections();
4133 Output_section_data* posd = new Output_data_strtab(&this->namepool_);
4134 os->add_output_section_data(posd);
4139 // Create the section headers. SIZE is 32 or 64. OFF is the file
4143 Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
4145 Output_section_headers* oshdrs;
4146 oshdrs = new Output_section_headers(this,
4147 &this->segment_list_,
4148 &this->section_list_,
4149 &this->unattached_section_list_,
4153 if (!parameters->incremental_update())
4154 off = align_address(*poff, oshdrs->addralign());
4157 oshdrs->pre_finalize_data_size();
4158 off = this->allocate(oshdrs->data_size(), oshdrs->addralign(), *poff);
4160 gold_fallback(_("out of patch space for section header table; "
4161 "relink with --incremental-full"));
4162 gold_debug(DEBUG_INCREMENTAL,
4163 "create_shdrs: %08lx %08lx (section header table)",
4164 static_cast<long>(off),
4165 static_cast<long>(off + oshdrs->data_size()));
4167 oshdrs->set_address_and_file_offset(0, off);
4168 off += oshdrs->data_size();
4171 this->section_headers_ = oshdrs;
4174 // Count the allocated sections.
4177 Layout::allocated_output_section_count() const
4179 size_t section_count = 0;
4180 for (Segment_list::const_iterator p = this->segment_list_.begin();
4181 p != this->segment_list_.end();
4183 section_count += (*p)->output_section_count();
4184 return section_count;
4187 // Create the dynamic symbol table.
4190 Layout::create_dynamic_symtab(const Input_objects* input_objects,
4191 Symbol_table* symtab,
4192 Output_section** pdynstr,
4193 unsigned int* plocal_dynamic_count,
4194 std::vector<Symbol*>* pdynamic_symbols,
4195 Versions* pversions)
4197 // Count all the symbols in the dynamic symbol table, and set the
4198 // dynamic symbol indexes.
4200 // Skip symbol 0, which is always all zeroes.
4201 unsigned int index = 1;
4203 // Add STT_SECTION symbols for each Output section which needs one.
4204 for (Section_list::iterator p = this->section_list_.begin();
4205 p != this->section_list_.end();
4208 if (!(*p)->needs_dynsym_index())
4209 (*p)->set_dynsym_index(-1U);
4212 (*p)->set_dynsym_index(index);
4217 // Count the local symbols that need to go in the dynamic symbol table,
4218 // and set the dynamic symbol indexes.
4219 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4220 p != input_objects->relobj_end();
4223 unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
4227 unsigned int local_symcount = index;
4228 *plocal_dynamic_count = local_symcount;
4230 index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
4231 &this->dynpool_, pversions);
4235 const int size = parameters->target().get_size();
4238 symsize = elfcpp::Elf_sizes<32>::sym_size;
4241 else if (size == 64)
4243 symsize = elfcpp::Elf_sizes<64>::sym_size;
4249 // Create the dynamic symbol table section.
4251 Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
4255 ORDER_DYNAMIC_LINKER,
4258 // Check for NULL as a linker script may discard .dynsym.
4261 Output_section_data* odata = new Output_data_fixed_space(index * symsize,
4264 dynsym->add_output_section_data(odata);
4266 dynsym->set_info(local_symcount);
4267 dynsym->set_entsize(symsize);
4268 dynsym->set_addralign(align);
4270 this->dynsym_section_ = dynsym;
4273 Output_data_dynamic* const odyn = this->dynamic_data_;
4276 odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
4277 odyn->add_constant(elfcpp::DT_SYMENT, symsize);
4280 // If there are more than SHN_LORESERVE allocated sections, we
4281 // create a .dynsym_shndx section. It is possible that we don't
4282 // need one, because it is possible that there are no dynamic
4283 // symbols in any of the sections with indexes larger than
4284 // SHN_LORESERVE. This is probably unusual, though, and at this
4285 // time we don't know the actual section indexes so it is
4286 // inconvenient to check.
4287 if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
4289 Output_section* dynsym_xindex =
4290 this->choose_output_section(NULL, ".dynsym_shndx",
4291 elfcpp::SHT_SYMTAB_SHNDX,
4293 false, ORDER_DYNAMIC_LINKER, false);
4295 if (dynsym_xindex != NULL)
4297 this->dynsym_xindex_ = new Output_symtab_xindex(index);
4299 dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
4301 dynsym_xindex->set_link_section(dynsym);
4302 dynsym_xindex->set_addralign(4);
4303 dynsym_xindex->set_entsize(4);
4305 dynsym_xindex->set_after_input_sections();
4307 // This tells the driver code to wait until the symbol table
4308 // has written out before writing out the postprocessing
4309 // sections, including the .dynsym_shndx section.
4310 this->any_postprocessing_sections_ = true;
4314 // Create the dynamic string table section.
4316 Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
4320 ORDER_DYNAMIC_LINKER,
4325 Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
4326 dynstr->add_output_section_data(strdata);
4329 dynsym->set_link_section(dynstr);
4330 if (this->dynamic_section_ != NULL)
4331 this->dynamic_section_->set_link_section(dynstr);
4335 odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
4336 odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
4340 // Create the hash tables. The Gnu-style hash table must be
4341 // built first, because it changes the order of the symbols
4342 // in the dynamic symbol table.
4344 if (strcmp(parameters->options().hash_style(), "gnu") == 0
4345 || strcmp(parameters->options().hash_style(), "both") == 0)
4347 unsigned char* phash;
4348 unsigned int hashlen;
4349 Dynobj::create_gnu_hash_table(*pdynamic_symbols, local_symcount,
4352 Output_section* hashsec =
4353 this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH,
4354 elfcpp::SHF_ALLOC, false,
4355 ORDER_DYNAMIC_LINKER, false);
4357 Output_section_data* hashdata = new Output_data_const_buffer(phash,
4361 if (hashsec != NULL && hashdata != NULL)
4362 hashsec->add_output_section_data(hashdata);
4364 if (hashsec != NULL)
4367 hashsec->set_link_section(dynsym);
4369 // For a 64-bit target, the entries in .gnu.hash do not have
4370 // a uniform size, so we only set the entry size for a
4372 if (parameters->target().get_size() == 32)
4373 hashsec->set_entsize(4);
4376 odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
4380 if (strcmp(parameters->options().hash_style(), "sysv") == 0
4381 || strcmp(parameters->options().hash_style(), "both") == 0)
4383 unsigned char* phash;
4384 unsigned int hashlen;
4385 Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
4388 Output_section* hashsec =
4389 this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH,
4390 elfcpp::SHF_ALLOC, false,
4391 ORDER_DYNAMIC_LINKER, false);
4393 Output_section_data* hashdata = new Output_data_const_buffer(phash,
4397 if (hashsec != NULL && hashdata != NULL)
4398 hashsec->add_output_section_data(hashdata);
4400 if (hashsec != NULL)
4403 hashsec->set_link_section(dynsym);
4404 hashsec->set_entsize(4);
4408 odyn->add_section_address(elfcpp::DT_HASH, hashsec);
4412 // Assign offsets to each local portion of the dynamic symbol table.
4415 Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
4417 Output_section* dynsym = this->dynsym_section_;
4421 off_t off = dynsym->offset();
4423 // Skip the dummy symbol at the start of the section.
4424 off += dynsym->entsize();
4426 for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
4427 p != input_objects->relobj_end();
4430 unsigned int count = (*p)->set_local_dynsym_offset(off);
4431 off += count * dynsym->entsize();
4435 // Create the version sections.
4438 Layout::create_version_sections(const Versions* versions,
4439 const Symbol_table* symtab,
4440 unsigned int local_symcount,
4441 const std::vector<Symbol*>& dynamic_symbols,
4442 const Output_section* dynstr)
4444 if (!versions->any_defs() && !versions->any_needs())
4447 switch (parameters->size_and_endianness())
4449 #ifdef HAVE_TARGET_32_LITTLE
4450 case Parameters::TARGET_32_LITTLE:
4451 this->sized_create_version_sections<32, false>(versions, symtab,
4453 dynamic_symbols, dynstr);
4456 #ifdef HAVE_TARGET_32_BIG
4457 case Parameters::TARGET_32_BIG:
4458 this->sized_create_version_sections<32, true>(versions, symtab,
4460 dynamic_symbols, dynstr);
4463 #ifdef HAVE_TARGET_64_LITTLE
4464 case Parameters::TARGET_64_LITTLE:
4465 this->sized_create_version_sections<64, false>(versions, symtab,
4467 dynamic_symbols, dynstr);
4470 #ifdef HAVE_TARGET_64_BIG
4471 case Parameters::TARGET_64_BIG:
4472 this->sized_create_version_sections<64, true>(versions, symtab,
4474 dynamic_symbols, dynstr);
4482 // Create the version sections, sized version.
4484 template<int size, bool big_endian>
4486 Layout::sized_create_version_sections(
4487 const Versions* versions,
4488 const Symbol_table* symtab,
4489 unsigned int local_symcount,
4490 const std::vector<Symbol*>& dynamic_symbols,
4491 const Output_section* dynstr)
4493 Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
4494 elfcpp::SHT_GNU_versym,
4497 ORDER_DYNAMIC_LINKER,
4500 // Check for NULL since a linker script may discard this section.
4503 unsigned char* vbuf;
4505 versions->symbol_section_contents<size, big_endian>(symtab,
4511 Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
4514 vsec->add_output_section_data(vdata);
4515 vsec->set_entsize(2);
4516 vsec->set_link_section(this->dynsym_section_);
4519 Output_data_dynamic* const odyn = this->dynamic_data_;
4520 if (odyn != NULL && vsec != NULL)
4521 odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
4523 if (versions->any_defs())
4525 Output_section* vdsec;
4526 vdsec = this->choose_output_section(NULL, ".gnu.version_d",
4527 elfcpp::SHT_GNU_verdef,
4529 false, ORDER_DYNAMIC_LINKER, false);
4533 unsigned char* vdbuf;
4534 unsigned int vdsize;
4535 unsigned int vdentries;
4536 versions->def_section_contents<size, big_endian>(&this->dynpool_,
4540 Output_section_data* vddata =
4541 new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
4543 vdsec->add_output_section_data(vddata);
4544 vdsec->set_link_section(dynstr);
4545 vdsec->set_info(vdentries);
4549 odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
4550 odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
4555 if (versions->any_needs())
4557 Output_section* vnsec;
4558 vnsec = this->choose_output_section(NULL, ".gnu.version_r",
4559 elfcpp::SHT_GNU_verneed,
4561 false, ORDER_DYNAMIC_LINKER, false);
4565 unsigned char* vnbuf;
4566 unsigned int vnsize;
4567 unsigned int vnentries;
4568 versions->need_section_contents<size, big_endian>(&this->dynpool_,
4572 Output_section_data* vndata =
4573 new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
4575 vnsec->add_output_section_data(vndata);
4576 vnsec->set_link_section(dynstr);
4577 vnsec->set_info(vnentries);
4581 odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
4582 odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
4588 // Create the .interp section and PT_INTERP segment.
4591 Layout::create_interp(const Target* target)
4593 gold_assert(this->interp_segment_ == NULL);
4595 const char* interp = parameters->options().dynamic_linker();
4598 interp = target->dynamic_linker();
4599 gold_assert(interp != NULL);
4602 size_t len = strlen(interp) + 1;
4604 Output_section_data* odata = new Output_data_const(interp, len, 1);
4606 Output_section* osec = this->choose_output_section(NULL, ".interp",
4607 elfcpp::SHT_PROGBITS,
4609 false, ORDER_INTERP,
4612 osec->add_output_section_data(odata);
4615 // Add dynamic tags for the PLT and the dynamic relocs. This is
4616 // called by the target-specific code. This does nothing if not doing
4619 // USE_REL is true for REL relocs rather than RELA relocs.
4621 // If PLT_GOT is not NULL, then DT_PLTGOT points to it.
4623 // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
4624 // and we also set DT_PLTREL. We use PLT_REL's output section, since
4625 // some targets have multiple reloc sections in PLT_REL.
4627 // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
4628 // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
4631 // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
4635 Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
4636 const Output_data* plt_rel,
4637 const Output_data_reloc_generic* dyn_rel,
4638 bool add_debug, bool dynrel_includes_plt)
4640 Output_data_dynamic* odyn = this->dynamic_data_;
4644 if (plt_got != NULL && plt_got->output_section() != NULL)
4645 odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got);
4647 if (plt_rel != NULL && plt_rel->output_section() != NULL)
4649 odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section());
4650 odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section());
4651 odyn->add_constant(elfcpp::DT_PLTREL,
4652 use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA);
4655 if ((dyn_rel != NULL && dyn_rel->output_section() != NULL)
4656 || (dynrel_includes_plt
4658 && plt_rel->output_section() != NULL))
4660 bool have_dyn_rel = dyn_rel != NULL && dyn_rel->output_section() != NULL;
4661 bool have_plt_rel = plt_rel != NULL && plt_rel->output_section() != NULL;
4662 odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
4664 ? dyn_rel->output_section()
4665 : plt_rel->output_section()));
4666 elfcpp::DT size_tag = use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ;
4667 if (have_dyn_rel && have_plt_rel && dynrel_includes_plt)
4668 odyn->add_section_size(size_tag,
4669 dyn_rel->output_section(),
4670 plt_rel->output_section());
4671 else if (have_dyn_rel)
4672 odyn->add_section_size(size_tag, dyn_rel->output_section());
4674 odyn->add_section_size(size_tag, plt_rel->output_section());
4675 const int size = parameters->target().get_size();
4680 rel_tag = elfcpp::DT_RELENT;
4682 rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size;
4683 else if (size == 64)
4684 rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size;
4690 rel_tag = elfcpp::DT_RELAENT;
4692 rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size;
4693 else if (size == 64)
4694 rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size;
4698 odyn->add_constant(rel_tag, rel_size);
4700 if (parameters->options().combreloc() && have_dyn_rel)
4702 size_t c = dyn_rel->relative_reloc_count();
4704 odyn->add_constant((use_rel
4705 ? elfcpp::DT_RELCOUNT
4706 : elfcpp::DT_RELACOUNT),
4711 if (add_debug && !parameters->options().shared())
4713 // The value of the DT_DEBUG tag is filled in by the dynamic
4714 // linker at run time, and used by the debugger.
4715 odyn->add_constant(elfcpp::DT_DEBUG, 0);
4719 // Finish the .dynamic section and PT_DYNAMIC segment.
4722 Layout::finish_dynamic_section(const Input_objects* input_objects,
4723 const Symbol_table* symtab)
4725 if (!this->script_options_->saw_phdrs_clause()
4726 && this->dynamic_section_ != NULL)
4728 Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
4731 oseg->add_output_section_to_nonload(this->dynamic_section_,
4732 elfcpp::PF_R | elfcpp::PF_W);
4735 Output_data_dynamic* const odyn = this->dynamic_data_;
4739 for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
4740 p != input_objects->dynobj_end();
4743 if (!(*p)->is_needed() && (*p)->as_needed())
4745 // This dynamic object was linked with --as-needed, but it
4750 odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
4753 if (parameters->options().shared())
4755 const char* soname = parameters->options().soname();
4757 odyn->add_string(elfcpp::DT_SONAME, soname);
4760 Symbol* sym = symtab->lookup(parameters->options().init());
4761 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4762 odyn->add_symbol(elfcpp::DT_INIT, sym);
4764 sym = symtab->lookup(parameters->options().fini());
4765 if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
4766 odyn->add_symbol(elfcpp::DT_FINI, sym);
4768 // Look for .init_array, .preinit_array and .fini_array by checking
4770 for(Layout::Section_list::const_iterator p = this->section_list_.begin();
4771 p != this->section_list_.end();
4773 switch((*p)->type())
4775 case elfcpp::SHT_FINI_ARRAY:
4776 odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p);
4777 odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p);
4779 case elfcpp::SHT_INIT_ARRAY:
4780 odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p);
4781 odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p);
4783 case elfcpp::SHT_PREINIT_ARRAY:
4784 odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p);
4785 odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p);
4791 // Add a DT_RPATH entry if needed.
4792 const General_options::Dir_list& rpath(parameters->options().rpath());
4795 std::string rpath_val;
4796 for (General_options::Dir_list::const_iterator p = rpath.begin();
4800 if (rpath_val.empty())
4801 rpath_val = p->name();
4804 // Eliminate duplicates.
4805 General_options::Dir_list::const_iterator q;
4806 for (q = rpath.begin(); q != p; ++q)
4807 if (q->name() == p->name())
4812 rpath_val += p->name();
4817 if (!parameters->options().enable_new_dtags())
4818 odyn->add_string(elfcpp::DT_RPATH, rpath_val);
4820 odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
4823 // Look for text segments that have dynamic relocations.
4824 bool have_textrel = false;
4825 if (!this->script_options_->saw_sections_clause())
4827 for (Segment_list::const_iterator p = this->segment_list_.begin();
4828 p != this->segment_list_.end();
4831 if ((*p)->type() == elfcpp::PT_LOAD
4832 && ((*p)->flags() & elfcpp::PF_W) == 0
4833 && (*p)->has_dynamic_reloc())
4835 have_textrel = true;
4842 // We don't know the section -> segment mapping, so we are
4843 // conservative and just look for readonly sections with
4844 // relocations. If those sections wind up in writable segments,
4845 // then we have created an unnecessary DT_TEXTREL entry.
4846 for (Section_list::const_iterator p = this->section_list_.begin();
4847 p != this->section_list_.end();
4850 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
4851 && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
4852 && (*p)->has_dynamic_reloc())
4854 have_textrel = true;
4860 if (parameters->options().filter() != NULL)
4861 odyn->add_string(elfcpp::DT_FILTER, parameters->options().filter());
4862 if (parameters->options().any_auxiliary())
4864 for (options::String_set::const_iterator p =
4865 parameters->options().auxiliary_begin();
4866 p != parameters->options().auxiliary_end();
4868 odyn->add_string(elfcpp::DT_AUXILIARY, *p);
4871 // Add a DT_FLAGS entry if necessary.
4872 unsigned int flags = 0;
4875 // Add a DT_TEXTREL for compatibility with older loaders.
4876 odyn->add_constant(elfcpp::DT_TEXTREL, 0);
4877 flags |= elfcpp::DF_TEXTREL;
4879 if (parameters->options().text())
4880 gold_error(_("read-only segment has dynamic relocations"));
4881 else if (parameters->options().warn_shared_textrel()
4882 && parameters->options().shared())
4883 gold_warning(_("shared library text segment is not shareable"));
4885 if (parameters->options().shared() && this->has_static_tls())
4886 flags |= elfcpp::DF_STATIC_TLS;
4887 if (parameters->options().origin())
4888 flags |= elfcpp::DF_ORIGIN;
4889 if (parameters->options().Bsymbolic()
4890 && !parameters->options().have_dynamic_list())
4892 flags |= elfcpp::DF_SYMBOLIC;
4893 // Add DT_SYMBOLIC for compatibility with older loaders.
4894 odyn->add_constant(elfcpp::DT_SYMBOLIC, 0);
4896 if (parameters->options().now())
4897 flags |= elfcpp::DF_BIND_NOW;
4899 odyn->add_constant(elfcpp::DT_FLAGS, flags);
4902 if (parameters->options().global())
4903 flags |= elfcpp::DF_1_GLOBAL;
4904 if (parameters->options().initfirst())
4905 flags |= elfcpp::DF_1_INITFIRST;
4906 if (parameters->options().interpose())
4907 flags |= elfcpp::DF_1_INTERPOSE;
4908 if (parameters->options().loadfltr())
4909 flags |= elfcpp::DF_1_LOADFLTR;
4910 if (parameters->options().nodefaultlib())
4911 flags |= elfcpp::DF_1_NODEFLIB;
4912 if (parameters->options().nodelete())
4913 flags |= elfcpp::DF_1_NODELETE;
4914 if (parameters->options().nodlopen())
4915 flags |= elfcpp::DF_1_NOOPEN;
4916 if (parameters->options().nodump())
4917 flags |= elfcpp::DF_1_NODUMP;
4918 if (!parameters->options().shared())
4919 flags &= ~(elfcpp::DF_1_INITFIRST
4920 | elfcpp::DF_1_NODELETE
4921 | elfcpp::DF_1_NOOPEN);
4922 if (parameters->options().origin())
4923 flags |= elfcpp::DF_1_ORIGIN;
4924 if (parameters->options().now())
4925 flags |= elfcpp::DF_1_NOW;
4926 if (parameters->options().Bgroup())
4927 flags |= elfcpp::DF_1_GROUP;
4929 odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
4932 // Set the size of the _DYNAMIC symbol table to be the size of the
4936 Layout::set_dynamic_symbol_size(const Symbol_table* symtab)
4938 Output_data_dynamic* const odyn = this->dynamic_data_;
4941 odyn->finalize_data_size();
4942 if (this->dynamic_symbol_ == NULL)
4944 off_t data_size = odyn->data_size();
4945 const int size = parameters->target().get_size();
4947 symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size);
4948 else if (size == 64)
4949 symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size);
4954 // The mapping of input section name prefixes to output section names.
4955 // In some cases one prefix is itself a prefix of another prefix; in
4956 // such a case the longer prefix must come first. These prefixes are
4957 // based on the GNU linker default ELF linker script.
4959 #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
4960 #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 }
4961 const Layout::Section_name_mapping Layout::section_name_mapping[] =
4963 MAPPING_INIT(".text.", ".text"),
4964 MAPPING_INIT(".rodata.", ".rodata"),
4965 MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"),
4966 MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"),
4967 MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"),
4968 MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"),
4969 MAPPING_INIT(".data.", ".data"),
4970 MAPPING_INIT(".bss.", ".bss"),
4971 MAPPING_INIT(".tdata.", ".tdata"),
4972 MAPPING_INIT(".tbss.", ".tbss"),
4973 MAPPING_INIT(".init_array.", ".init_array"),
4974 MAPPING_INIT(".fini_array.", ".fini_array"),
4975 MAPPING_INIT(".sdata.", ".sdata"),
4976 MAPPING_INIT(".sbss.", ".sbss"),
4977 // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled
4978 // differently depending on whether it is creating a shared library.
4979 MAPPING_INIT(".sdata2.", ".sdata"),
4980 MAPPING_INIT(".sbss2.", ".sbss"),
4981 MAPPING_INIT(".lrodata.", ".lrodata"),
4982 MAPPING_INIT(".ldata.", ".ldata"),
4983 MAPPING_INIT(".lbss.", ".lbss"),
4984 MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"),
4985 MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"),
4986 MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"),
4987 MAPPING_INIT(".gnu.linkonce.t.", ".text"),
4988 MAPPING_INIT(".gnu.linkonce.r.", ".rodata"),
4989 MAPPING_INIT(".gnu.linkonce.d.", ".data"),
4990 MAPPING_INIT(".gnu.linkonce.b.", ".bss"),
4991 MAPPING_INIT(".gnu.linkonce.s.", ".sdata"),
4992 MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"),
4993 MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"),
4994 MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"),
4995 MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"),
4996 MAPPING_INIT(".gnu.linkonce.td.", ".tdata"),
4997 MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"),
4998 MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"),
4999 MAPPING_INIT(".gnu.linkonce.l.", ".ldata"),
5000 MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"),
5001 MAPPING_INIT(".ARM.extab", ".ARM.extab"),
5002 MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
5003 MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
5004 MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
5007 #undef MAPPING_INIT_EXACT
5009 const int Layout::section_name_mapping_count =
5010 (sizeof(Layout::section_name_mapping)
5011 / sizeof(Layout::section_name_mapping[0]));
5013 // Choose the output section name to use given an input section name.
5014 // Set *PLEN to the length of the name. *PLEN is initialized to the
5018 Layout::output_section_name(const Relobj* relobj, const char* name,
5021 // gcc 4.3 generates the following sorts of section names when it
5022 // needs a section name specific to a function:
5028 // .data.rel.local.FN
5030 // .data.rel.ro.local.FN
5037 // The GNU linker maps all of those to the part before the .FN,
5038 // except that .data.rel.local.FN is mapped to .data, and
5039 // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
5040 // beginning with .data.rel.ro.local are grouped together.
5042 // For an anonymous namespace, the string FN can contain a '.'.
5044 // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
5045 // GNU linker maps to .rodata.
5047 // The .data.rel.ro sections are used with -z relro. The sections
5048 // are recognized by name. We use the same names that the GNU
5049 // linker does for these sections.
5051 // It is hard to handle this in a principled way, so we don't even
5052 // try. We use a table of mappings. If the input section name is
5053 // not found in the table, we simply use it as the output section
5056 const Section_name_mapping* psnm = section_name_mapping;
5057 for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
5059 if (psnm->fromlen > 0)
5061 if (strncmp(name, psnm->from, psnm->fromlen) == 0)
5063 *plen = psnm->tolen;
5069 if (strcmp(name, psnm->from) == 0)
5071 *plen = psnm->tolen;
5077 // As an additional complication, .ctors sections are output in
5078 // either .ctors or .init_array sections, and .dtors sections are
5079 // output in either .dtors or .fini_array sections.
5080 if (is_prefix_of(".ctors.", name) || is_prefix_of(".dtors.", name))
5082 if (parameters->options().ctors_in_init_array())
5085 return name[1] == 'c' ? ".init_array" : ".fini_array";
5090 return name[1] == 'c' ? ".ctors" : ".dtors";
5093 if (parameters->options().ctors_in_init_array()
5094 && (strcmp(name, ".ctors") == 0 || strcmp(name, ".dtors") == 0))
5096 // To make .init_array/.fini_array work with gcc we must exclude
5097 // .ctors and .dtors sections from the crtbegin and crtend
5100 || (!Layout::match_file_name(relobj, "crtbegin")
5101 && !Layout::match_file_name(relobj, "crtend")))
5104 return name[1] == 'c' ? ".init_array" : ".fini_array";
5111 // Return true if RELOBJ is an input file whose base name matches
5112 // FILE_NAME. The base name must have an extension of ".o", and must
5113 // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is
5114 // to match crtbegin.o as well as crtbeginS.o without getting confused
5115 // by other possibilities. Overall matching the file name this way is
5116 // a dreadful hack, but the GNU linker does it in order to better
5117 // support gcc, and we need to be compatible.
5120 Layout::match_file_name(const Relobj* relobj, const char* match)
5122 const std::string& file_name(relobj->name());
5123 const char* base_name = lbasename(file_name.c_str());
5124 size_t match_len = strlen(match);
5125 if (strncmp(base_name, match, match_len) != 0)
5127 size_t base_len = strlen(base_name);
5128 if (base_len != match_len + 2 && base_len != match_len + 3)
5130 return memcmp(base_name + base_len - 2, ".o", 2) == 0;
5133 // Check if a comdat group or .gnu.linkonce section with the given
5134 // NAME is selected for the link. If there is already a section,
5135 // *KEPT_SECTION is set to point to the existing section and the
5136 // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and
5137 // IS_GROUP_NAME are recorded for this NAME in the layout object,
5138 // *KEPT_SECTION is set to the internal copy and the function returns
5142 Layout::find_or_add_kept_section(const std::string& name,
5147 Kept_section** kept_section)
5149 // It's normal to see a couple of entries here, for the x86 thunk
5150 // sections. If we see more than a few, we're linking a C++
5151 // program, and we resize to get more space to minimize rehashing.
5152 if (this->signatures_.size() > 4
5153 && !this->resized_signatures_)
5155 reserve_unordered_map(&this->signatures_,
5156 this->number_of_input_files_ * 64);
5157 this->resized_signatures_ = true;
5160 Kept_section candidate;
5161 std::pair<Signatures::iterator, bool> ins =
5162 this->signatures_.insert(std::make_pair(name, candidate));
5164 if (kept_section != NULL)
5165 *kept_section = &ins.first->second;
5168 // This is the first time we've seen this signature.
5169 ins.first->second.set_object(object);
5170 ins.first->second.set_shndx(shndx);
5172 ins.first->second.set_is_comdat();
5174 ins.first->second.set_is_group_name();
5178 // We have already seen this signature.
5180 if (ins.first->second.is_group_name())
5182 // We've already seen a real section group with this signature.
5183 // If the kept group is from a plugin object, and we're in the
5184 // replacement phase, accept the new one as a replacement.
5185 if (ins.first->second.object() == NULL
5186 && parameters->options().plugins()->in_replacement_phase())
5188 ins.first->second.set_object(object);
5189 ins.first->second.set_shndx(shndx);
5194 else if (is_group_name)
5196 // This is a real section group, and we've already seen a
5197 // linkonce section with this signature. Record that we've seen
5198 // a section group, and don't include this section group.
5199 ins.first->second.set_is_group_name();
5204 // We've already seen a linkonce section and this is a linkonce
5205 // section. These don't block each other--this may be the same
5206 // symbol name with different section types.
5211 // Store the allocated sections into the section list.
5214 Layout::get_allocated_sections(Section_list* section_list) const
5216 for (Section_list::const_iterator p = this->section_list_.begin();
5217 p != this->section_list_.end();
5219 if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
5220 section_list->push_back(*p);
5223 // Store the executable sections into the section list.
5226 Layout::get_executable_sections(Section_list* section_list) const
5228 for (Section_list::const_iterator p = this->section_list_.begin();
5229 p != this->section_list_.end();
5231 if (((*p)->flags() & (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR))
5232 == (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR))
5233 section_list->push_back(*p);
5236 // Create an output segment.
5239 Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
5241 gold_assert(!parameters->options().relocatable());
5242 Output_segment* oseg = new Output_segment(type, flags);
5243 this->segment_list_.push_back(oseg);
5245 if (type == elfcpp::PT_TLS)
5246 this->tls_segment_ = oseg;
5247 else if (type == elfcpp::PT_GNU_RELRO)
5248 this->relro_segment_ = oseg;
5249 else if (type == elfcpp::PT_INTERP)
5250 this->interp_segment_ = oseg;
5255 // Return the file offset of the normal symbol table.
5258 Layout::symtab_section_offset() const
5260 if (this->symtab_section_ != NULL)
5261 return this->symtab_section_->offset();
5265 // Return the section index of the normal symbol table. It may have
5266 // been stripped by the -s/--strip-all option.
5269 Layout::symtab_section_shndx() const
5271 if (this->symtab_section_ != NULL)
5272 return this->symtab_section_->out_shndx();
5276 // Write out the Output_sections. Most won't have anything to write,
5277 // since most of the data will come from input sections which are
5278 // handled elsewhere. But some Output_sections do have Output_data.
5281 Layout::write_output_sections(Output_file* of) const
5283 for (Section_list::const_iterator p = this->section_list_.begin();
5284 p != this->section_list_.end();
5287 if (!(*p)->after_input_sections())
5292 // Write out data not associated with a section or the symbol table.
5295 Layout::write_data(const Symbol_table* symtab, Output_file* of) const
5297 if (!parameters->options().strip_all())
5299 const Output_section* symtab_section = this->symtab_section_;
5300 for (Section_list::const_iterator p = this->section_list_.begin();
5301 p != this->section_list_.end();
5304 if ((*p)->needs_symtab_index())
5306 gold_assert(symtab_section != NULL);
5307 unsigned int index = (*p)->symtab_index();
5308 gold_assert(index > 0 && index != -1U);
5309 off_t off = (symtab_section->offset()
5310 + index * symtab_section->entsize());
5311 symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
5316 const Output_section* dynsym_section = this->dynsym_section_;
5317 for (Section_list::const_iterator p = this->section_list_.begin();
5318 p != this->section_list_.end();
5321 if ((*p)->needs_dynsym_index())
5323 gold_assert(dynsym_section != NULL);
5324 unsigned int index = (*p)->dynsym_index();
5325 gold_assert(index > 0 && index != -1U);
5326 off_t off = (dynsym_section->offset()
5327 + index * dynsym_section->entsize());
5328 symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
5332 // Write out the Output_data which are not in an Output_section.
5333 for (Data_list::const_iterator p = this->special_output_list_.begin();
5334 p != this->special_output_list_.end();
5338 // Write out the Output_data which are not in an Output_section
5339 // and are regenerated in each iteration of relaxation.
5340 for (Data_list::const_iterator p = this->relax_output_list_.begin();
5341 p != this->relax_output_list_.end();
5346 // Write out the Output_sections which can only be written after the
5347 // input sections are complete.
5350 Layout::write_sections_after_input_sections(Output_file* of)
5352 // Determine the final section offsets, and thus the final output
5353 // file size. Note we finalize the .shstrab last, to allow the
5354 // after_input_section sections to modify their section-names before
5356 if (this->any_postprocessing_sections_)
5358 off_t off = this->output_file_size_;
5359 off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
5361 // Now that we've finalized the names, we can finalize the shstrab.
5363 this->set_section_offsets(off,
5364 STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
5366 if (off > this->output_file_size_)
5369 this->output_file_size_ = off;
5373 for (Section_list::const_iterator p = this->section_list_.begin();
5374 p != this->section_list_.end();
5377 if ((*p)->after_input_sections())
5381 this->section_headers_->write(of);
5384 // If a tree-style build ID was requested, the parallel part of that computation
5385 // is already done, and the final hash-of-hashes is computed here. For other
5386 // types of build IDs, all the work is done here.
5389 Layout::write_build_id(Output_file* of, unsigned char* array_of_hashes,
5390 size_t size_of_hashes) const
5392 if (this->build_id_note_ == NULL)
5395 unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
5396 this->build_id_note_->data_size());
5398 if (array_of_hashes == NULL)
5400 const size_t output_file_size = this->output_file_size();
5401 const unsigned char* iv = of->get_input_view(0, output_file_size);
5402 const char* style = parameters->options().build_id();
5404 // If we get here with style == "tree" then the output must be
5405 // too small for chunking, and we use SHA-1 in that case.
5406 if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0))
5407 sha1_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov);
5408 else if (strcmp(style, "md5") == 0)
5409 md5_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov);
5413 of->free_input_view(0, output_file_size, iv);
5417 // Non-overlapping substrings of the output file have been hashed.
5418 // Compute SHA-1 hash of the hashes.
5419 sha1_buffer(reinterpret_cast<const char*>(array_of_hashes),
5420 size_of_hashes, ov);
5421 delete[] array_of_hashes;
5424 of->write_output_view(this->build_id_note_->offset(),
5425 this->build_id_note_->data_size(),
5429 // Write out a binary file. This is called after the link is
5430 // complete. IN is the temporary output file we used to generate the
5431 // ELF code. We simply walk through the segments, read them from
5432 // their file offset in IN, and write them to their load address in
5433 // the output file. FIXME: with a bit more work, we could support
5434 // S-records and/or Intel hex format here.
5437 Layout::write_binary(Output_file* in) const
5439 gold_assert(parameters->options().oformat_enum()
5440 == General_options::OBJECT_FORMAT_BINARY);
5442 // Get the size of the binary file.
5443 uint64_t max_load_address = 0;
5444 for (Segment_list::const_iterator p = this->segment_list_.begin();
5445 p != this->segment_list_.end();
5448 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
5450 uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
5451 if (max_paddr > max_load_address)
5452 max_load_address = max_paddr;
5456 Output_file out(parameters->options().output_file_name());
5457 out.open(max_load_address);
5459 for (Segment_list::const_iterator p = this->segment_list_.begin();
5460 p != this->segment_list_.end();
5463 if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
5465 const unsigned char* vin = in->get_input_view((*p)->offset(),
5467 unsigned char* vout = out.get_output_view((*p)->paddr(),
5469 memcpy(vout, vin, (*p)->filesz());
5470 out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
5471 in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
5478 // Print the output sections to the map file.
5481 Layout::print_to_mapfile(Mapfile* mapfile) const
5483 for (Segment_list::const_iterator p = this->segment_list_.begin();
5484 p != this->segment_list_.end();
5486 (*p)->print_sections_to_mapfile(mapfile);
5487 for (Section_list::const_iterator p = this->unattached_section_list_.begin();
5488 p != this->unattached_section_list_.end();
5490 (*p)->print_to_mapfile(mapfile);
5493 // Print statistical information to stderr. This is used for --stats.
5496 Layout::print_stats() const
5498 this->namepool_.print_stats("section name pool");
5499 this->sympool_.print_stats("output symbol name pool");
5500 this->dynpool_.print_stats("dynamic name pool");
5502 for (Section_list::const_iterator p = this->section_list_.begin();
5503 p != this->section_list_.end();
5505 (*p)->print_merge_stats();
5508 // Write_sections_task methods.
5510 // We can always run this task.
5513 Write_sections_task::is_runnable()
5518 // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
5522 Write_sections_task::locks(Task_locker* tl)
5524 tl->add(this, this->output_sections_blocker_);
5525 if (this->input_sections_blocker_ != NULL)
5526 tl->add(this, this->input_sections_blocker_);
5527 tl->add(this, this->final_blocker_);
5530 // Run the task--write out the data.
5533 Write_sections_task::run(Workqueue*)
5535 this->layout_->write_output_sections(this->of_);
5538 // Write_data_task methods.
5540 // We can always run this task.
5543 Write_data_task::is_runnable()
5548 // We need to unlock FINAL_BLOCKER when finished.
5551 Write_data_task::locks(Task_locker* tl)
5553 tl->add(this, this->final_blocker_);
5556 // Run the task--write out the data.
5559 Write_data_task::run(Workqueue*)
5561 this->layout_->write_data(this->symtab_, this->of_);
5564 // Write_symbols_task methods.
5566 // We can always run this task.
5569 Write_symbols_task::is_runnable()
5574 // We need to unlock FINAL_BLOCKER when finished.
5577 Write_symbols_task::locks(Task_locker* tl)
5579 tl->add(this, this->final_blocker_);
5582 // Run the task--write out the symbols.
5585 Write_symbols_task::run(Workqueue*)
5587 this->symtab_->write_globals(this->sympool_, this->dynpool_,
5588 this->layout_->symtab_xindex(),
5589 this->layout_->dynsym_xindex(), this->of_);
5592 // Write_after_input_sections_task methods.
5594 // We can only run this task after the input sections have completed.
5597 Write_after_input_sections_task::is_runnable()
5599 if (this->input_sections_blocker_->is_blocked())
5600 return this->input_sections_blocker_;
5604 // We need to unlock FINAL_BLOCKER when finished.
5607 Write_after_input_sections_task::locks(Task_locker* tl)
5609 tl->add(this, this->final_blocker_);
5615 Write_after_input_sections_task::run(Workqueue*)
5617 this->layout_->write_sections_after_input_sections(this->of_);
5620 // Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes,
5621 // or as a "tree" where each chunk of the string is hashed and then those
5622 // hashes are put into a (much smaller) string which is hashed with sha1.
5623 // We compute a checksum over the entire file because that is simplest.
5626 Build_id_task_runner::run(Workqueue* workqueue, const Task*)
5628 Task_token* post_hash_tasks_blocker = new Task_token(true);
5629 const Layout* layout = this->layout_;
5630 Output_file* of = this->of_;
5631 const size_t filesize = (layout->output_file_size() <= 0 ? 0
5632 : static_cast<size_t>(layout->output_file_size()));
5633 unsigned char* array_of_hashes = NULL;
5634 size_t size_of_hashes = 0;
5636 if (strcmp(this->options_->build_id(), "tree") == 0
5637 && this->options_->build_id_chunk_size_for_treehash() > 0
5639 && (filesize >= this->options_->build_id_min_file_size_for_treehash()))
5641 static const size_t MD5_OUTPUT_SIZE_IN_BYTES = 16;
5642 const size_t chunk_size =
5643 this->options_->build_id_chunk_size_for_treehash();
5644 const size_t num_hashes = ((filesize - 1) / chunk_size) + 1;
5645 post_hash_tasks_blocker->add_blockers(num_hashes);
5646 size_of_hashes = num_hashes * MD5_OUTPUT_SIZE_IN_BYTES;
5647 array_of_hashes = new unsigned char[size_of_hashes];
5648 unsigned char *dst = array_of_hashes;
5649 for (size_t i = 0, src_offset = 0; i < num_hashes;
5650 i++, dst += MD5_OUTPUT_SIZE_IN_BYTES, src_offset += chunk_size)
5652 size_t size = std::min(chunk_size, filesize - src_offset);
5653 workqueue->queue(new Hash_task(of,
5657 post_hash_tasks_blocker));
5661 // Queue the final task to write the build id and close the output file.
5662 workqueue->queue(new Task_function(new Close_task_runner(this->options_,
5667 post_hash_tasks_blocker,
5668 "Task_function Close_task_runner"));
5671 // Close_task_runner methods.
5673 // Finish up the build ID computation, if necessary, and write a binary file,
5674 // if necessary. Then close the output file.
5677 Close_task_runner::run(Workqueue*, const Task*)
5679 // At this point the multi-threaded part of the build ID computation,
5680 // if any, is done. See Build_id_task_runner.
5681 this->layout_->write_build_id(this->of_, this->array_of_hashes_,
5682 this->size_of_hashes_);
5684 // If we've been asked to create a binary file, we do so here.
5685 if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
5686 this->layout_->write_binary(this->of_);
5691 // Instantiate the templates we need. We could use the configure
5692 // script to restrict this to only the ones for implemented targets.
5694 #ifdef HAVE_TARGET_32_LITTLE
5697 Layout::init_fixed_output_section<32, false>(
5699 elfcpp::Shdr<32, false>& shdr);
5702 #ifdef HAVE_TARGET_32_BIG
5705 Layout::init_fixed_output_section<32, true>(
5707 elfcpp::Shdr<32, true>& shdr);
5710 #ifdef HAVE_TARGET_64_LITTLE
5713 Layout::init_fixed_output_section<64, false>(
5715 elfcpp::Shdr<64, false>& shdr);
5718 #ifdef HAVE_TARGET_64_BIG
5721 Layout::init_fixed_output_section<64, true>(
5723 elfcpp::Shdr<64, true>& shdr);
5726 #ifdef HAVE_TARGET_32_LITTLE
5729 Layout::layout<32, false>(Sized_relobj_file<32, false>* object,
5732 const elfcpp::Shdr<32, false>& shdr,
5733 unsigned int, unsigned int, off_t*);
5736 #ifdef HAVE_TARGET_32_BIG
5739 Layout::layout<32, true>(Sized_relobj_file<32, true>* object,
5742 const elfcpp::Shdr<32, true>& shdr,
5743 unsigned int, unsigned int, off_t*);
5746 #ifdef HAVE_TARGET_64_LITTLE
5749 Layout::layout<64, false>(Sized_relobj_file<64, false>* object,
5752 const elfcpp::Shdr<64, false>& shdr,
5753 unsigned int, unsigned int, off_t*);
5756 #ifdef HAVE_TARGET_64_BIG
5759 Layout::layout<64, true>(Sized_relobj_file<64, true>* object,
5762 const elfcpp::Shdr<64, true>& shdr,
5763 unsigned int, unsigned int, off_t*);
5766 #ifdef HAVE_TARGET_32_LITTLE
5769 Layout::layout_reloc<32, false>(Sized_relobj_file<32, false>* object,
5770 unsigned int reloc_shndx,
5771 const elfcpp::Shdr<32, false>& shdr,
5772 Output_section* data_section,
5773 Relocatable_relocs* rr);
5776 #ifdef HAVE_TARGET_32_BIG
5779 Layout::layout_reloc<32, true>(Sized_relobj_file<32, true>* object,
5780 unsigned int reloc_shndx,
5781 const elfcpp::Shdr<32, true>& shdr,
5782 Output_section* data_section,
5783 Relocatable_relocs* rr);
5786 #ifdef HAVE_TARGET_64_LITTLE
5789 Layout::layout_reloc<64, false>(Sized_relobj_file<64, false>* object,
5790 unsigned int reloc_shndx,
5791 const elfcpp::Shdr<64, false>& shdr,
5792 Output_section* data_section,
5793 Relocatable_relocs* rr);
5796 #ifdef HAVE_TARGET_64_BIG
5799 Layout::layout_reloc<64, true>(Sized_relobj_file<64, true>* object,
5800 unsigned int reloc_shndx,
5801 const elfcpp::Shdr<64, true>& shdr,
5802 Output_section* data_section,
5803 Relocatable_relocs* rr);
5806 #ifdef HAVE_TARGET_32_LITTLE
5809 Layout::layout_group<32, false>(Symbol_table* symtab,
5810 Sized_relobj_file<32, false>* object,
5812 const char* group_section_name,
5813 const char* signature,
5814 const elfcpp::Shdr<32, false>& shdr,
5815 elfcpp::Elf_Word flags,
5816 std::vector<unsigned int>* shndxes);
5819 #ifdef HAVE_TARGET_32_BIG
5822 Layout::layout_group<32, true>(Symbol_table* symtab,
5823 Sized_relobj_file<32, true>* object,
5825 const char* group_section_name,
5826 const char* signature,
5827 const elfcpp::Shdr<32, true>& shdr,
5828 elfcpp::Elf_Word flags,
5829 std::vector<unsigned int>* shndxes);
5832 #ifdef HAVE_TARGET_64_LITTLE
5835 Layout::layout_group<64, false>(Symbol_table* symtab,
5836 Sized_relobj_file<64, false>* object,
5838 const char* group_section_name,
5839 const char* signature,
5840 const elfcpp::Shdr<64, false>& shdr,
5841 elfcpp::Elf_Word flags,
5842 std::vector<unsigned int>* shndxes);
5845 #ifdef HAVE_TARGET_64_BIG
5848 Layout::layout_group<64, true>(Symbol_table* symtab,
5849 Sized_relobj_file<64, true>* object,
5851 const char* group_section_name,
5852 const char* signature,
5853 const elfcpp::Shdr<64, true>& shdr,
5854 elfcpp::Elf_Word flags,
5855 std::vector<unsigned int>* shndxes);
5858 #ifdef HAVE_TARGET_32_LITTLE
5861 Layout::layout_eh_frame<32, false>(Sized_relobj_file<32, false>* object,
5862 const unsigned char* symbols,
5864 const unsigned char* symbol_names,
5865 off_t symbol_names_size,
5867 const elfcpp::Shdr<32, false>& shdr,
5868 unsigned int reloc_shndx,
5869 unsigned int reloc_type,
5873 #ifdef HAVE_TARGET_32_BIG
5876 Layout::layout_eh_frame<32, true>(Sized_relobj_file<32, true>* object,
5877 const unsigned char* symbols,
5879 const unsigned char* symbol_names,
5880 off_t symbol_names_size,
5882 const elfcpp::Shdr<32, true>& shdr,
5883 unsigned int reloc_shndx,
5884 unsigned int reloc_type,
5888 #ifdef HAVE_TARGET_64_LITTLE
5891 Layout::layout_eh_frame<64, false>(Sized_relobj_file<64, false>* object,
5892 const unsigned char* symbols,
5894 const unsigned char* symbol_names,
5895 off_t symbol_names_size,
5897 const elfcpp::Shdr<64, false>& shdr,
5898 unsigned int reloc_shndx,
5899 unsigned int reloc_type,
5903 #ifdef HAVE_TARGET_64_BIG
5906 Layout::layout_eh_frame<64, true>(Sized_relobj_file<64, true>* object,
5907 const unsigned char* symbols,
5909 const unsigned char* symbol_names,
5910 off_t symbol_names_size,
5912 const elfcpp::Shdr<64, true>& shdr,
5913 unsigned int reloc_shndx,
5914 unsigned int reloc_type,
5918 #ifdef HAVE_TARGET_32_LITTLE
5921 Layout::add_to_gdb_index(bool is_type_unit,
5922 Sized_relobj<32, false>* object,
5923 const unsigned char* symbols,
5926 unsigned int reloc_shndx,
5927 unsigned int reloc_type);
5930 #ifdef HAVE_TARGET_32_BIG
5933 Layout::add_to_gdb_index(bool is_type_unit,
5934 Sized_relobj<32, true>* object,
5935 const unsigned char* symbols,
5938 unsigned int reloc_shndx,
5939 unsigned int reloc_type);
5942 #ifdef HAVE_TARGET_64_LITTLE
5945 Layout::add_to_gdb_index(bool is_type_unit,
5946 Sized_relobj<64, false>* object,
5947 const unsigned char* symbols,
5950 unsigned int reloc_shndx,
5951 unsigned int reloc_type);
5954 #ifdef HAVE_TARGET_64_BIG
5957 Layout::add_to_gdb_index(bool is_type_unit,
5958 Sized_relobj<64, true>* object,
5959 const unsigned char* symbols,
5962 unsigned int reloc_shndx,
5963 unsigned int reloc_type);
5966 } // End namespace gold.